Organization, Consolidation and Presentation of Financial Statements [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Dow Jones [Member] Dow Jones [Member] Dow Jones CME Group net of non-controlling interest [Member] CME Group net of non-controlling interest [Member] CME Group net of non-controlling interest [Member] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] S&P/Dow Jones Indices LLC [Member] S&P/Dow Jones Indices LLC [Member] S&P/Dow Jones Indices LLC [Member] Index Services [Member] Index Services [Member] Business Acquisition [Line Items] Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Entity [Abstract] Entity [Abstract] Entities [Table] Entities [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Class B Common Stock, Class B1 [Member] Class B Common Stock, Class B1 [member] Class B Common Stock, Class B1 [Member] Class B Common Stock, Class B2 [Member] Class B Common Stock, Class B2 [member] Class B Common Stock, Class B2 [Member] Class B Common Stock, Class B3 [Member] Class B Common Stock, Class B3 [Member] Class B Common Stock, Class B3 [Member] Class B Common Stock, Class B4 [Member] Class B Common Stock, Class B4 [member] Class B Common Stock, Class B4 [Member] Class A Common Stock (Shares) [Member] Common Class A [Member] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Temporary Equity [Abstract] Noncontrolling Interest [Table] Noncontrolling Interest [Table] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Adjustments to Additional Paid in Capital, Deferred Tax Liabilities Adjustments to Additional Paid in Capital, Deferred Tax Liabilities Adjustments to Additional Paid in Capital, Deferred Tax Liabilities Gain on Purchase of NonControlling Interest Gain on Purchase of NonControlling Interest Gain on Purchase of NonControlling Interest Temporary Equity, Carrying Value of Purchased Interest Temporary Equity, Carrying Value of Purchased Interest Temporary Equity, Carrying Value of Purchased Interest Changes in Redeemable Non-controlling Interest [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Balance at January 1 Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest Allocation of stokc-based compensation Temporary Equity, Other Changes Total comprehensive income attributable to redeemable non-controlling interest Comprehensive Income (Loss), Net of Tax, Attributable to Redeemable Non-controlling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Redeemable Non-controlling Interest Balance at December 31 Valuation and Qualifying Accounts [Abstract] Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Commitments [Abstract] Commitments [Abstract] Schedule of future minimum payments under non-cancelable operating leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of other commitments Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block] Income Tax Disclosure [Abstract] Reconciliation of Unrecognized Tax Benefits [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance as of January 1 Unrecognized Tax Benefits Additions based on tax positions related to the current year Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions Additions for tax positions of prior years Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions Reductions for tax positions of prior years Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions Reductions resulting from the lapse of statutes of limitations Unrecognized Tax Benefits, Reductions Resulting from Lapse of Applicable Statute of Limitations Settlements with taxing authorities Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities Balance as of December 31 Intangible Assets and Goodwill [Abstract] Intangible Assets and Goodwill [Abstract] Intangible Assets and Goodwill Goodwill and Intangible Assets Disclosure [Text Block] Statement [Table] Statement [Table] Goodwill by Segment [Axis] Business Segments [Axis] Goodwill, Segment [Domain] Segment [Domain] CBOT holdings [Member] CBOT Holdings [Member] CBOT Holdings [Member] NYMEX holdings [Member] NYMEX Holdings [Member] NYMEX Holdings [Member] Index Services [Member] Other Affiliates [Member] Other Affiliates [Member] Statement [Line Items] Statement [Line Items] Total Goodwill, beginning balance Goodwill Business Combinations Goodwill, Acquired During Period Goodwill, Written off Related to Sale of Business Unit Goodwill, Written off Related to Sale of Business Unit Other Activity Goodwill, Translation and Purchase Accounting Adjustments Total Goodwill, ending balance Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Inputs, level 3 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair value of liability at period start Business Acquisition, Contingent Consideration, at Fair Value Contingent obligation arising from acquisition Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease) Included in operating expense Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Fair value of liability at period end Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Share-based Compensation [Abstract] Compensation expense for stock-based payments and total income tax benefit recognized Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Nonvested Share Activity [Table Text Block] Schedule of Nonvested Share Activity [Table Text Block] Statement of Financial Position [Abstract] Series A junior participating preferred stock [Member] Series A Preferred Stock [Member] Class B Common Stock (Shares) [Member] Common Class B [Member] Assets Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Marketable Securities, Current Accounts receivable, net of allowance of $1.2 and $0.8 Accounts Receivable, Net, Current Other current assets (includes $40.0 in restricted cash) Other Assets, Current Cash performance bonds and guaranty fund contributions Good Faith and Margin Deposits with Broker-Dealers Total current assets Assets, Current Property, net of accumulated depreciation and amortization Property, Plant and Equipment, Net Intangible assets-trading products Other Indefinite-lived Intangible Assets Intangible assets-other, net Intangible Assets, Net (Excluding Goodwill) Goodwill Other assets (includes $74.0 and $73.0 in restricted cash) Other Assets, Noncurrent Total Assets Assets Liabilities and Shareholders' Equity Liabilities and Equity [Abstract] Accounts payable Accounts Payable, Current Short-term debt Short-term Non-bank Loans and Notes Payable Other current liabilities Other Liabilities, Current Cash performance bonds and guaranty fund contributions Cash Performance Bonds and Security Deposit Liability The amount due to other broker-dealers in the form of a deposit paid by the counterparty to demonstrate an intention to complete a purchase (good faith deposit) and also the amount due to a customer in the form of collateral deposited by the counterparty to cover the credit risk assumed by the entity (margin deposit). Total current liabilities Liabilities, Current Long-term debt Unsecured Long-term Debt, Noncurrent Deferred tax liabilities, net Deferred Tax Assets, Net, Noncurrent Other liabilities Other Liabilities, Noncurrent Total Liabilities Liabilities Redeemable non-controlling interest Shareholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.01 par value, 10,000 shares authorized, none issued or outstanding Preferred Stock, Value, Issued Common stock Common Stock, Value, Outstanding Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total Shareholders' Equity Stockholders' Equity Attributable to Parent Non-controlling interest Stockholders' Equity Attributable to Noncontrolling Interest Total Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total Liabilities and Shareholders' Equity Liabilities and Equity Long-term Investments [Abstract] Long-term Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Statement of Stockholders' Equity Parentheticals [Abstract] Statement of Stockholders' Equity Parentheticals [Abstract] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Report Date [Axis] Report Date [Axis] Financial Statements Date [Domain] Financial Statements Date [Domain] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Domain] Adjustments for Change in Accounting Principle [Domain] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Common Stock, Dividends, Per Share, Declared Common Stock, Dividends, Per Share, Declared Debt [Abstract] Debt [Abstract] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Term Loan Due 2011, Interest Equal To 3-Month LIBOR Plus 1.00%, Reset Quarterly [Member] Term Loan Due 2011, Interest Equal To 3-Month LIBOR Plus 1.00%, Reset Quarterly [Member] Term Loan Due 2011, Interest Equal To 3-Month LIBOR Plus 1.00%, Reset Quarterly Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Four Point Three Zero Percent [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Four Point Three Zero Percent [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Four Point Three Zero Percent [Member] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Forward starting interest rate swap agreement fixed rate Forward starting interest rate swap agreement fixed rate Forward starting interest rate swap agreement, fixed rate Debt instrument, face amount Debt Instrument, Face Amount Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding in Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding in Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding in Shares [Roll Forward] Number of shares outstanding at December 31, 2010 (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Number of shares granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Number of shares exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Number of shares cancelled Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Number of shares outstanding at December 31, 2011 (shares) Number of shares exercisable at December 31, 2011 (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted average exercise price granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted average exercise price exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted average exercise price cancelled Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Weighted average exercise price outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted average exercise price exercisable at December 31, 2011 Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Weighted average remaining contractual life outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Aggregate intrinsic value outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Aggregate intrinsic value exercisable at December 31, 2011 Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Marketable Securities [Abstract] Available-for-sale securities Available-for-sale Securities [Table Text Block] Amortized cost and fair value of marketable securities by contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Short-term Debt Schedule of Short-term Debt [Table Text Block] Schedule of Long-term Debt Schedule of Long-term Debt Instruments [Table Text Block] Long-term debt maturities at par value Schedule of Maturities of Long-term Debt [Table Text Block] Fair value of fixed rate notes by maturity date Fair Value Of Fixed Rate Notes By Maturity Date [Text Block] Fair Value Of Fixed Rate Notes By Maturity Date [Text Block] Capital Stock [abstract] Capital Stock [Abstract] Capital Stock Capital Stock [Text Block] Capital Stock [Text Block] General Discussion of Pension and Other Postretirement Benefits [Abstract] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Pension Plans [Member] Pension Plans, Defined Benefit [Member] Components of Net Pension Expense: Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Recognized net actuarial loss Defined Benefit Plan, Amortization of Gains (Losses) Net Pension Expense Defined Benefit Plan, Net Periodic Benefit Cost Assumptions Used to Determine End-of-Year Benefit Obligation: Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Cash Balance Interest Crediting Rate Cash Balance Interest Crediting Rate Assumptions Used to Determine Net Pension Expense: Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Expected return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Cash Balance Interest Crediting Rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Cash Balance Interest Crediting Rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Cash Balance Interest Crediting Rate Capital stock Schedule of Stock by Class [Table Text Block] Redeemable Non-controlling Interest Temporary Equity [Table Text Block] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Performance Bonds and Guaranty Fund Contributions [Abstract] Performance Bonds And Security Deposits [Abstract] Performance bonds Performance Bond Letters Of Credit Performance Bond Letters Of Credit Guaranty Fund Letters of Credit Guaranty Fund Letters of Credit Guaranty Fund Letters of Credit Performance collateral for delivery Performance collateral for delivery Performance collateral for delivery Total Letters of Credit Letters of Credit Letters of Credit Class A Common Stock Common Stock, Shares Authorized Common Stock, Shares Authorized Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Defined Benefit Plan by Plan Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] US Equity [Member] US Equity [Member] US Equity [Member] Foreign Equity [Member] Foreign Equity Mutual Fund [Member] Foreign Equity Mutual Fund [Member] Fixed Income [Member] Fixed Income Funds [Member] Commodity [Member] Commodity [Member] Minimum Defined Benefit Plan, Target Plan Asset Allocations Range Minimum Maximum Defined Benefit Plan, Target Plan Asset Allocations Range Maximum Guarantees [Abstract] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] MFGlobal [Member] MFGlobal [Member] MFGlobal [Member] Family Farmer and Ranchers Protection Fund [Member] Family Farmer and Ranchers Protection Fund [Member] Family Farmer and Ranchers Protection Fund [Member] Credit Rating [Axis] Credit Rating [Axis] Credit Rating [Domain] Credit Rating [Domain] Underlying Asset Class [Axis] Underlying Asset Class [Axis] Underlying Asset Class [Domain] Underlying Asset Class [Domain] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Guarantor Obligations, Current Carrying Value Guarantor Obligations, Current Carrying Value PaymentPerParticipant PaymentPerParticipant PaymentPerParticipant Contingent liability to SGX, amount of irrevocable letters of credit Guarantor Obligations, Collateral Held Directly or by Third Parties PaymentPerCooperative PaymentPerCooperative PaymentPerCooperative FutureLosses FutureLosses FutureLosses Payments under Guarantee Payments under Guarantee Payments under Guarantee Guarantor Obligations, Maximum Exposure, Undiscounted Guarantor Obligations, Maximum Exposure, Undiscounted Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Domestic Tax Authority [Member] Domestic Tax Authority [Member] BM&F [Member] BM& FBOVESPA SA [Member] BM&FBOVESPA SA [Member] Operating Loss Carryforwards Operating Loss Carryforwards unrealized capital tax loss unrealized capital tax loss unrealized capital tax loss Deferred Tax Assets, Valuation Allowance, Noncurrent Deferred Tax Assets, Valuation Allowance, Noncurrent Deferred Tax Assets, Unrealized Currency Losses Deferred Tax Assets, Unrealized Currency Losses Long-term deferred tax asset Deferred Tax Assets, Gross, Noncurrent Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Allowance for doubtful accounts Allowance for Doubtful Accounts [Member] Allowance for deferred tax assets Valuation Allowance of Deferred Tax Assets [Member] Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Movement in Valuation Allowances and Reserves [Roll Forward] Movement in Valuation Allowances and Reserves [Roll Forward] Balance at beginning of year Valuation Allowances and Reserves, Balance Charged against goodwill Valuation Allowances and Reserves, Reserves of Businesses Acquired Charged (credited) to costs and expenses Valuation Allowances and Reserves, Charged to Cost and Expense Other Valuation Allowances and Reserves, Charged to Other Accounts Balance at end of year Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Clearing Firm, Market Data, and Other Customer Relationships [Member] Customer Relationships [Member] Lease Agreements [Member] Lease Agreements [Member] Technology-Related Intellectual Property [Member] Developed Technology Rights [Member] Other - Finite [Member] Other Intangible Assets [Member] Foreign Currency Translation Adjustments [Member] Foreign Currency Translation Adjustments [Member] Foreign Currency Translation Adjustments [Member] Total Amortizable Intangible Assets, Net [Member] Total Amortizable Intangible Assets, Net [Member] Total Amortizable Intangible Assets Net [Member] Indefinite-lived Intangible Assets by Major Class [Axis] Indefinite-lived Intangible Assets by Major Class [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Trade Names [Member] Trade Names [Member] Cost Finite-Lived Intangible Assets, Gross Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Net book value Finite-Lived Intangible Assets, Net Indefinite-lived Intangible Assets Indefinite-Lived Intangible Assets (Excluding Goodwill) Other Indefinite-lived Intangible Assets Quarterly Financial Data [Abstract] Total Revenues Revenues Operating Income Operating Income (Loss) Non-operating income (expense) Nonoperating Income (Expense) Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Net income attributable to CME Group Net Income (Loss) Attributable to Parent Earnings per Common Share Attributable to CME Group: Earnings Per Share [Abstract] Basic Earnings Per Share, Basic Diluted Earnings Per Share, Diluted Weighted Average Number of Common Shares: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic Weighted Average Number of Shares Outstanding, Basic Diluted Weighted Average Number of Shares Outstanding, Diluted Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Statement of Stockholders' Equity [Abstract] Common Stock and Additional Paid-in Capital [Member] Common Stock Including Additional Paid in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) [Member] Accumulated Other Comprehensive Income (Loss) [Member] Parent [Member] Parent [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Common Stock, Shares, Outstanding Comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Net Income (Loss) Attributable to Noncontrolling Interest Net Income (Loss) Attributable to Noncontrolling Interest Net income including portion attributable to nonredeemable non-controlling interest Net income including portion attributable to nonredeemable non-controlling interest Net income including portion attributable to nonredeemable non-controlling interest Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Total comprehensive income attributable to CME Group Comprehensive Income (Loss), Net of Tax, Attributable to Parent Cash dividend on common stock Dividends, Cash Repurchase of Class A common stock (in shares) Stock Repurchased During Period, Shares Stock Repurchased During Period, Value Stock Repurchased During Period, Value Adjustments to Additional Paid in Capital, Other Adjustments to Additional Paid in Capital, Other Exercise of stock options (in shares) Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Excess tax benefits from option exercises and restricted stock vesting Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Vesting of issued restricted Class A common stock (in shares) Vesting Of Issued Restricted Stock Number of shares issued during the period as a result of the vesting of restricted stock units. Vesting of issued restricted Class A common stock Vesting Of Issued Restricted Stock Value Vesting Of Issued Restricted Stock Shares issued to Board of Directors (in shares) Stock Issued To Related Parties During Period Shares Number of shares of stock issued during the period to related parties. Shares issued to Board of Directors Stock Issued To Related Parties During Period Value Value of stock issued during the period to related parties. Shares issued under Employee Stock Purchase Plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Shares issued under Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Stock-based compensation Stock Granted During Period, Value, Share-based Compensation, Net of Forfeitures Balance (in shares) Components of intangible assets Intangible Assets Disclosure [Text Block] Weighted average useful life for the amortizable intangible assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Future estimated amortization expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Goodwill activity Schedule of Goodwill [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Basic and diluted earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Major Property Class [Axis] Major Property Class [Axis] Major Property Class [Domain] Major Property Class [Domain] First Lease Renewal Option [Member] First Lease Renewal Option [Member] First Lease Renewal Option [Member] Second Lease Renewal Option [Member] Second Lease Renewal Option [Member] Second Lease Renewal Option [Member] Property Subject to or Available for Operating Lease [Axis] Property Subject to or Available for Operating Lease [Axis] Property Subject to or Available for Operating Lease [Domain] Property Subject to or Available for Operating Lease [Domain] NYMEX [Member] NYMEX [Member] NYMEX [Member] Chicago CBOT Building [Member] [Member] Chicago CBOT Building [Member] [Member] Chicago CBOT Building [Member] [Member] Chicago [Member] Chicago [Member] Chicago [Member] Additional Office Space Chicago [Member] Additional Office Space Chicago [Member] Additional Office Space Chicago [Member] Operating leases number of renewal options Operating Leases Number Of Renewal Options Operating leases number of renewal options Operating leases renewal option, period (in years) Operating Leases Renewal Option, Period Operating leases renewal option, period Operating leases, rent expense Operating Leases, Rent Expense Performance Bonds and Guaranty Fund Contributions Performance Bonds And Security Deposits [TextBlock] Performance Bonds And Security Deposits [TextBlock] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] CME Group Omnibus Stock Plan [Member] CME Group Omnibus Stock Plan [Member] CME Group Omnibus Stock Plan [Member] CBOT Holdings Long-Term Equity Plan [Member] CBOT Holdings Long-Term Equity Plan [Member] CBOT Holdings Long-Term Equity Plan [Member] NYMEX Holdings Omnibus Long-Term Incentive Plan [Member] NYMEX Holdings Omnibus Long-Term Incentive Plan [Member] NYMEX Holdings Omnibus Long-Term Incentive Plan [Member] Director Stock Plan; Class A Shares [Member] Director Stock Plan; Class A Shares [Member] Director Stock Plan; Class A Shares [Member] Employee Stock Purchase Plan; Class A Shares [Member] Employee Stock Purchase Plan; Class A Shares [Member] Employee Stock Purchase Plan; Class A Shares [Member] Share Repurchases; Class A Common Stock [Member] Share Repurchases Class A Common Stock [Member] Share Repurchases; Class A Common Stock [Member] Core Rights [Member] Core Rights [Member] Core Rights [Member] Other Voting Rights [Member] Other Voting Rights [Member] Other Voting Rights [Member] Class B Common Stock (Shares) Class B common stock, Class B1, B2, B3 [Member] Class B common stock, Class B1, B2, B3 [Member] Class B common stock, Class B1, B2, B3 [Member] Common Stock, Par or Stated Value Per Share Common Stock, Par or Stated Value Per Share Common stock, voting rights Common Stock, Voting Rights Number of directors Number of directors Number of directors Shares granted, outstanding and exercised Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Number of shares reserved for awards under the plan Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares authorized for future awards, frozen awards Shares Authorized For Future Awards Under The Plan Frozen Shares Authorized For Future Awards Under The Plan Frozen Class A shares awarded under Director Stock Plan Class A shares awarded under Director Stock Plan Class A shares awarded under Director Stock Plan Market value of the shares an Employee Stock Purchase Plan Market value of the shares an Employee Stock Purchase Plan Market value of the shares an Employee Stock Purchase Plan Class A shares Purchased under Employee Stock Purchase Plan Class A shares Purchased under Employee Stock Purchase Plan Class A shares Purchased under Employee Stock Purchase Plan Share Buyback Program Stock Repurchased And Retired Authorized Stock Repurchased And Retired Authorized Number of Shares Company Repurchased Stock Repurchased and Retired During Period, Shares Average Purchase Price Per Share Stock Repurchased And Retired Average Price Per Share Stock Repurchased And Retired Average Price Per Share Total Cost of Repurchased Shares Stock Repurchased and Retired During Period, Value Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Balance at January 1 Defined Benefit Plan, Benefit Obligation Actuarial (gain) loss Defined Benefit Plan, Actuarial Gain (Loss) Benefits paid Defined Benefit Plan, Benefits Paid Balance at December 31 Statutory U.S. federal tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate State taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes Effective Income Tax Rate Reconciliation, Deductions, Qualified Production Activities Effective Income Tax Rate Reconciliation, Deductions, Qualified Production Activities Increase (decrease) in domestic valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance Impact of revised state apportionment estimates Impact of Revised State Appointment Estimates Impact of Revised State Appointment Estimates Effective Income Tax Rate Reconciliation, Disposition of Business Effective Income Tax Rate Reconciliation, Disposition of Business Other, net Effective Income Tax Rate Reconciliation, Other Adjustments Effective Tax Rate Effective Income Tax Rate, Continuing Operations CONTINGENCIES [Abstract] CONTINGENCIES [Abstract] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Bankruptcy Claims, Amount of Claims Settled Bankruptcy Claims, Amount of Claims Settled Bankruptcy Settlement Returned to Customers Bankruptcy Settlement Returned to Customers Bankruptcy Settlement Returned to Customers Accrued liability related to all outstanding legal matters Estimated Litigation Liability 2014 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2015 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2017 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Loss Contingency [Abstract] Contingencies Schedule of Loss Contingencies by Contingency [Table Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Investment Securities [Member] Investment Securities [Member] Investment Securities [Member] Pension Plans, Defined Benefit [Member] Derivative Financial Instruments, Assets [Member] Derivative Financial Instruments, Assets [Member] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Stockholders' Equity Attributable to Parent Balance at beginning of period Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Reclassification of gain on sale of security Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax Net actuarial gain (loss) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax Balance at end of period Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Comprehensive Income Before Reclassification Adjustments Comprehensive Income Before Reclassification Adjustments Comprehensive Income Before Reclassification Adjustments Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax Comprehensive Income Reclassification Adjustments Comprehensive Income Reclassification Adjustments Comprehensive Income Reclassification Adjustments Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Other Comprehensive Income (Loss), Net of Tax Comprehensive Income, Tax Comprehensive Income, Tax Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Principles of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Investment, Policy [Policy Text Block] Investment, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Derivative Investments Derivatives, Policy [Policy Text Block] Accounts Receivable Receivables, Policy [Policy Text Block] Performance Bonds and Guaranty Fund Contributions Performance Bonds And Security Deposit [Text Block] Performance Bonds And Security Deposit [Text Block] Property, Equipment and Leasehold Improvements Property, Plant and Equipment, Policy [Policy Text Block] Operating Leases Revenue Recognition Leases, Operating [Policy Text Block] Goodwill and Other Intangible Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Business Combinations Business Combinations and Other Purchase of Business Transactions, Policy [Policy Text Block] Employee Benefit Plans Compensation Related Costs, Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Share-Based Payments Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Marketing Costs Advertising Costs, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Segment Reporting Segment Reporting Disclosure [Text Block] Schedule of Held-to-maturity Securities [Table] Schedule of Held-to-maturity Securities [Table] Schedule of Held-to-maturity Securities, Major Types of Debt and Equity Securities [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Schedule of Held-to-maturity Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Maturity of one year or less, Amortized Cost Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Maturity between one and five years, Amortized Cost Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Maturity between five and ten years, Amortized Cost Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Maturity greater than ten years, Amortized Cost Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Total, Amortized Cost Available-for-sale Securities, Debt Maturities, Amortized Cost Basis Maturity of one year or less, Fair Value Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Maturity between one and five years, Fair Value Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Maturity between five and ten years, Fair Value Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Maturity greater than ten years, Fair Value Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Total, Fair Value Available-for-sale Securities, Debt Securities $750.0 Million Fixed Rate Notes Due February 2014, Interest Equal To 5.75% [Member] Seven Hundred Fifty Million Dollar Fixed Rate Notes Due February Twenty Fourteen, Interest Equal To Five Point Seven Five Percent [Member] $750.0 Million Fixed Rate Notes Due August 2014, Interest Equal To 5.75% $612.5 Million Fixed Rate Notes Due March 2018, Interest Equal To 4.40% [Member] Six Hundred Twelve Point Five Million Fixed Rate Notes Due March Two Thousand Eighteen, Interest Equal To Four Point Four Zero Percent [Member] $612.5 Million Fixed Rate Notes Due March 2018, Interest Equal To 4.40% Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Three Point Zero Percent [Member] [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Three Point Zero Percent [Member] [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Three Point Zero Percent [Member] [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Forty Three, Interest Equal To Five Point Three Percent [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Forty Three, Interest Equal To Five Point Three Percent [Member] Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Forty Three, Interest Equal To Five Point Three Percent Debt instrument, fair value Debt Instrument, Fair Value Disclosure Debt Instrument, maturity date Debt Instrument, Maturity Date Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Inputs, Discount Rate Fair Value Inputs, Discount Rate Valulation Model Probability Low Range Valulation Model Probability Low Range Valulation Model Probability Low Range fair value inputs probability of payout Valuation Model Probability High Range Valuation Model Probability High Range Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Cash [Member] Cash [Member] Non-Cash Deposits and IEF Funds [Member] Securities and IEF Funds [Member] Securities and IEF Funds [Member] Performance bonds Performance bonds Performance bonds Guaranty Fund Contributions Guaranty Fund Contributions Guaranty Fund Contributions Cross-margin arrangements Cross-margin arrangements Cross-margin arrangements Total $750.0 Million Fixed Rate Notes Due August Two Thousand Thirteen, Interest Equal To Five Point Four Zero Percent [Member] Seven Hundred Fifty Million Fixed Rate Notes Due August Two Thousand Thirteen, Interest Equal To Five Point Four Zero Percent [Member] Fixed Rate Notes Due August 2013, Interest Equal To 5.40%, $750.0 Million Short-term Debt Short-term Debt [Abstract] Long-term Debt Long-term Debt, Current and Noncurrent [Abstract] KANSAS CITY BOARD OF TRADE [Member] KANSAS CITY BOARD OF TRADE [Member] CBOT Building [Member] CBOT Building [Member] CBOT Building [Member] CMA [Member] CMA [Member] CMA [Member] Net book value Disposal Group, Including Discontinued Operation, Intangible Assets, Net Disposal Group, Including Discontinued Operation, Intangible Assets, Net Acquired Finite-lived Intangible Asset, Amount Acquired Finite-lived Intangible Asset, Amount Amortization of purchased intangibles Amortization of Intangible Assets Bolsa Mexicana De Valores, S A B De C V [Member] Bolsa Mexicana De Valores, S A B De C V [Member] Bolsa Mexicana De Valores, S A B De C V Bursa Malaysia Derivatives Berhad [Member] Bursa Malaysia Derivatives Berhad [Member] Bursa Malaysia Derivatives Berhad [Member] DME Holdings [Member] DME Holdings [Member] DME Holdings [Member] S&P/DJI [Member] SandPDJI [Member] SandPDJI [Member] Fair value of investment Investment Owned, at Fair Value Cost-basis value of investment Investment Owned, at Cost Organization and Business Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Summary of the change in projected benefit obligation Schedule of Changes in Projected Benefit Obligations [Table Text Block] Change in plan assets Schedule of Changes in Fair Value of Plan Assets [Table Text Block] Fair value of plan assets Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Components of net pension expenses and the assumptions used to determine the end-of-year projected benefit obligation and net pension expense in aggregate Schedule of Net Benefit Costs [Table Text Block] Asset allocation for the plan Schedule of Allocation of Plan Assets [Table Text Block] Prior service costs and actuarial losses included in accumulated other comprehensive income (loss) Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Anticipated benefit payments from the plan in future years Schedule of Expected Benefit Payments [Table Text Block] Income Statement [Abstract] Revenues Revenues [Abstract] Clearing and transaction fees Clearing And Execution Servicing Fees earned by providing executing servicing and clearing, net of rebates. Market data and information services Market Data Revenue Access and communication fees Access and communication fees Revenue from providing access fees to customers for the use of electronic trading platform and revenue from telecommunication networks and communication services. Other Other Revenue, Net Total Revenues Expenses Costs and Expenses [Abstract] Compensation and benefits Labor and Related Expense Communications Communication Technology support services Information Technology and Data Processing Professional fees and outside services Professional Fees Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Occupancy and building operations Occupancy, Net Licensing and other fee agreements License Costs Other Other Cost and Expense, Operating Total Expenses Costs and Expenses Operating Income Non-Operating Income (Expense) Nonoperating Income (Expense) [Abstract] Investment income Investment Income, Nonoperating Gains (losses) on derivative investments Gain (Loss) on Derivative Instruments, Net, Pretax Interest and other borrowing costs Interest and Debt Expense Equity in net (gains) losses of unconsolidated subsidiaries Income (Loss) from Equity Method Investments Other income (expense) Other Nonoperating Income (Expense) Total Non-Operating Income tax provision Income Tax Expense (Benefit) Net Income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Less: net income attributable to redeemable non-controlling interest Net Income attributable to Redeemable non-controlling interest and non-controlling interest Net Income attributable to Redeemable non-controlling interest and non-controlling interest Net Income Attributable to CME Group General Discussion of Derivative Instruments and Hedging Activities [Abstract] Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Income Taxes Income Tax Disclosure [Text Block] Property, Plant and Equipment, Net [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Land and land improvements Land and Land Improvements [Member] Building and building improvements Building and Building Improvements [Member] Leasehold improvements Leasehold Improvements [Member] Furniture, fixtures and equipment Furniture and Fixtures [Member] Software and software development costs Software and Software Development Costs [Member] Property, Plant and Equipment [Line Items] Proceeds from sale of building property Proceeds from Sale of Property, Plant, and Equipment Gain (Loss) on Sale of Property Plant Equipment Gain (Loss) on Sale of Property Plant Equipment Property, gross Property, Plant and Equipment, Gross Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, net Estimated useful life, minimum Property, Plant and Equipment, Useful Life Deferred Gain on Sale of Property Deferred Gain on Sale of Property Guarantees Schedule of Guarantor Obligations [Table Text Block] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Net income Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Derivative, Net Hedge Ineffectiveness Gain (Loss) Derivative, Net Hedge Ineffectiveness Gain (Loss) Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Parent Summary of the Property Accounts Property, Plant and Equipment [Table Text Block] Stock-Based Payments Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Compensation expense Allocated Share-based Compensation Expense Income tax benefit recognized Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Statement of Cash Flows [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Stock-based compensation Share-based Compensation MF Global accounts receivable write-off Provision for Doubtful Accounts Gain on sale of Index Services assets Gain (Loss) on Sale of Other Assets Gain on contribution of Dow Jones Index asset group gain on contribution of assets gain on contribution of assets Loss on sale of Credit Market Analysis Ltd. Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Gain (Loss) on Sale of Property Plant Equipment Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Deferred income taxes Deferred Income Tax Expense (Benefit) Change in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Other current assets Increase (Decrease) in Prepaid Expense and Other Assets Other assets Increase (Decrease) in Other Operating Assets Accounts payable Increase (Decrease) in Accounts Payable Income tax payable Increase (Decrease) in Income Taxes Payable Other current liabilities Increase (Decrease) in Other Accrued Liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities Other Other Noncash Income (Expense) Net Cash Provided by Operating Activities Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from maturities of available-for-sale marketable securities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Purchases of available-for-sale marketable securities Payments to Acquire Available-for-sale Securities Purchases of property, net Payments to Acquire Property, Plant, and Equipment Consideration paid in business combinations, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Investments in business ventures Payments to Acquire Investments Proceeds from sale of Credit Market Analysis Ltd., net of cash sold with business ProceedsFromDivestitureOfBusinessNet ProceedsFromDivestitureOfBusinessNet Proceeds from sale of Index Services assets Proceeds from Sale of Other Assets Settlement of derivative related to debt issuance Payments for (Proceeds from) Derivative Instrument, Investing Activities Other Payments for (Proceeds from) Other Investing Activities Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from other borrowings, net of issuance costs Proceeds from Issuance of Long-term Debt Repayment of other borrowings Repayments of Other Debt Cash dividends Payments of Dividends Repurchase of Class A common stock, including costs Payments for Repurchase of Common Stock Proceeds from exercise of stock options Proceeds from Stock Options Exercised Distribution paid to non-controlling interest Payments to Noncontrolling Interests Excess tax benefits related to employee option exercises and restricted stock vesting Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities Contingent Consideration Settlement Contingent Consideration Settlement Contingent Consideration Settlement Other Proceeds from (Payments for) Other Financing Activities Net Cash Provided by (Used in) Financing Activities Net Cash Provided by (Used in) Financing Activities Net change in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and Cash Equivalents, End of Period Supplemental Disclosure of Cash Flow Information Supplemental Cash Flow Information [Abstract] Income taxes paid Income Taxes Paid Interest paid (excluding securities lending program) Interest Paid Non-cash investing activities: Cash Flow Noncash Investing Disclosure Abstract Cash Flow, Noncash Investing Disclosure [Abstract] Investment in S&P/Dow Jones Indices LLC Noncash or Part Noncash Acquisition, Investments Acquired Non-cash financing activities: Cash Flow Noncash Financing Activities Disclosure Abstract Cash Flow, Noncash Financing Activities Disclosure [Abstract] dividends declared dividends declared dividends declared Deferred Compensation Arrangement with Individual, Postretirement Benefits, by Type of Deferred Compensation [Axis] Postretirement Benefits, Type of Deferred Compensation [Axis] Type of Deferred Compensation [Domain] Type of Deferred Compensation, All Types [Domain] Savings Plans [Member] Defined Contribution Pension [Member] Non-Qualified Plans [Member] Non-Qualified Plans [Member] Non-Qualified Plans NYMEX Members' Retirement Plan and Benefits [Member] NYMEX Members' Retirement Plan and Benefits [Member] Retirement Plan and Benefits Age for participation eligibility in benefit plan Eligible Age To Participate In Benefit Plan Eligible age to participate in benefit plan Years of service for vesting eligibility Years Of Service For Vesting Eligibility Years of service for vesting eligibility Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Excess of pension plan assets over the projected benefit obligation Defined Benefit Plan, Funded Status of Plan Defined Benefit Plan Funding Goal Percentage Defined Benefit Plan Funding Goal Percentage Defined Benefit Plan Funding Goal Percentage Estimated liabilities exceeding the fair value of the plan assets Pension Plans Benefit Obligation Liabilities Exceeded Fair Value Of Plan Assets Pension Plans Benefit Obligation Liabilities Exceeded Fair Value Of Plan Assets Estimated contribution to meet projected excess of pension plan liabilities of pension plan assets Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year Amortization of actuarial loss from accumulated other comprehensive income (loss) into net periodic benefit costs Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year Percentage of employees base salary matched by employer, maximum Defined Contribution Plan, Employer Matching Contribution, Percent Aggregate expense from merging of saving plans Defined Contribution Plan, Cost Recognized Trading Securities Trading Securities Minimum annual contribution NYMEX Members' Retirement Plan and Benefits Minimum Annual Contribution NYMEX Members Retirement Plan And Benefits Minimum Annual Contribution NYMEX Members Retirement Plan And Benefits Total contribution Total Contribution To NYMEX Members Retirement Plan And Benefits Total Contribution To NYMEX Members Retirement Plan And Benefits Total obligation Total Obligation to NYMEX Members Retirement Plan and Benefits Total Obligation to NYMEX Members Retirement Plan and Benefits Fair value of assets Fair Value Of Assets Under NYMEX Members Retirement Plan And Benefits Fair Value Of Assets Under NYMEX Members Retirement Plan And Benefits Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Liabilities [Member] Other Liabilities [Member] ExpectedReclassificationAdjustment ExpectedReclassificationAdjustment ExpectedReclassificationAdjustment Derivative, Notional Amount Derivative, Notional Amount Fair value of the interest rate derivative instruments Interest Rate Cash Flow Hedge Derivative at Fair Value, Net Schedule of Trading Securities and Other Trading Assets, Major Types of Trading Securities and Assets [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Trading Securities and Assets [Domain] Major Types of Debt and Equity Securities [Domain] Asset-backed Securities [Member] Asset-backed Securities [Member] Fair value of asset-back securities Asset-Backed Securities, at Carrying Value Unrealized losses Available-for-sale Securities, Gross Unrealized Losses Trading securities fair value Guaranty Fund [Axis] Guaranty Fund [Axis] Guaranty Fund [Axis] Guaranty Fund [Domain] Guaranty Fund [Domain] [Domain] for Guaranty Fund [Axis] CME Base Guaranty Fund [Member] CME Base Guaranty Fund [Member] CME Base Guaranty Fund [Member] CME IRS Guaranty Fund [Member] [Member] CME IRS Guaranty Fund [Member] [Member] CME IRS Guaranty Fund [Member] [Member] CME CDS Guaranty Fund [Member] [Member] CME CDS Guaranty Fund [Member] [Member] CME CDS Guaranty Fund [Member] [Member] CMECE Commodity Fund [Member] CMECE Commodity Fund [Member] CMECE Commodity Fund [Member] CMECE Interest Rate Swap [Member] CMECE Interest Rate Swap [Member] CMECE Interest Rate Swap [Member] Line of Credit Facility [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] 364-day fully secured, committed line of credit Line of Credit Facility, Fully Secured Committed [Member] Line of Credit Facility, Fully Secured Committed [Member] Revolving senior credit facility Letter of Credit Facility, Revolving Senior Credit Facility [Member] Letter of Credit Facility, Revolving Senior Credit Facility [Member] Average daily clearing settlement Average Daily Clearing Settlement Average Daily Clearing Settlement Total principal in IEF programs Total principal in IEF programs Total principal in IEF programs Revolving line of credit Line of Credit, Current Management fees earned under the IEF programs I E F Revenue I E F Revenue Percentage share of cross-margining collateral Percentage Share of Cross-margining Collateral Percentage Share of Cross-margining Collateral Corporate Contribution Corporate Contribution Corporate Contribution Minimum Corporate Contribution Minimum Corporate Contribution Minimum Corporate Contribution Working capital designated for clearance of default in over the counter credit default swap, percent Working Capital Percent For Over the Counter Credit Default Swap, Percent Working Capital Percent For Over the Counter Credit Default Swap, Percent Working capital designated for clearance of default in over the counter interest rate swap Working Capital For Over the Counter Interest Rate Swap Working Capital For Over the Counter Interest Rate Swap Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Line of Credit, Guaranty Fund Collateral Available Line of Credit, Guaranty Fund Collateral Available Line of Credit, Guaranty Fund Collateral Available Option on increase in line of credit Line of Credit Facility, Option to Increase, Maximum Borrowing Capacity Line of Credit Facility, Option to Increase, Maximum Borrowing Capacity Days fully secured Committed Line Of Credit Number Of Days Fully Secured Committed Line Of Credit Number Of Days Fully Secured Intraday settlements of cash performance bonds Intraday settlements of cash performance bonds Intraday settlements of cash performance bonds Cash and securities held as performance bonds and guaranty fund contributions at fair value Cash And Securities Held As Performance Bonds And Security Deposits At Fair Value [TextBlock] Cash And Securities Held As Performance Bonds And Security Deposits At Fair Value [TextBlock] Letters of credit Schedule of Letters of Credit [Text Block] Schedule of Letters of Credit. Financial instruments measured at fair value on a recurring basis Fair Value, Measurement Inputs, Disclosure [Text Block] Reconciliation of assets and liabilities valued at fair value on a recurring basis using significant unobservable inputs (level 3) Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Accumulated Other Comprehensive Income [Abstract] Accumulated Other Comprehensive Income [Abstract] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Prior Service Cost Balance Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax Actuarila Loss Balance Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax Unrecognized loss Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Prior Service Cost Balance Fair Value, Inputs, level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, level 2 [Member] Fair Value, Inputs, Level 2 [Member] US Treasury Securities [Member] US Treasury Securities [Member] Mutual funds [Member] Mutual funds [Member] Mutual Funds [Member] Equity Securities [Member] Equity Securities [Member] Available-for-sale Securities at Fair Value Available-for-sale Securities, Fair Value Disclosure Trading Securities at Fair Value Trading Securities, Fair Value Disclosure Marketable Securities at Fair Value Investments, Fair Value Disclosure Investment Owned, at Fair Value Total Assets at Fair Value Assets, Fair Value Disclosure Interest Rate Swap Contracts at Fair Value Derivative Financial Instruments, Liabilities, Fair Value Disclosure Contingent consideration at Fair Value Total liabilities at fair value Liabilities, Fair Value Disclosure Quarterly Information Quarterly Financial Information [Text Block] Investment Type [Axis] Investment Type [Axis] Investment Type [Domain] Investment Type Categorization [Domain] Available-for-Sale Securities Amortized Cost Available-for-sale Securities, Amortized Cost Basis Available-for-Sale Securities Fair Value Available-for-sale Securities Number of shares outstanding at December 31, 2010 (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Number of shares granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Number of shares vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Number of shares cancelled Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Number of shares outstanding at December 31, 2011 (shares) Weighted average grant date fair value granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted average grant date fair value vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted average grant date fair value cancelled Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Weighted average grant date fair value outstanding Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Money Market Funds [Member] Money Market Funds [Member] Actual allocation of plan assets, Fixed income Defined Benefit Plan, Actual Plan Asset Allocations Derivative Instrument Risk [Axis] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] Derivative Contract Type [Domain] Derivative Instruments, Gain (Loss) by Income Statement Location [Axis] Income Statement Location [Axis] Income Statement and Other Comprehensive Income Location [Domain] Income Statement Location [Domain] Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax 2014 Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months 2015 Defined Benefit Plan, Expected Future Benefit Payments, Year Two 2016 Defined Benefit Plan, Expected Future Benefit Payments, Year Three 2017 Defined Benefit Plan, Expected Future Benefit Payments, Year Four 2018 Defined Benefit Plan, Expected Future Benefit Payments, Year Five 2019-2023 Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Effect of derivative instruments on the statements of Income and Shareholders' Equity Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Operating Leases, Future Minimum Payments Due [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2012 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2013 Operating Leases, Future Minimum Payments, Due in Two Years 2014 Operating Leases, Future Minimum Payments, Due in Three Years 2015 Operating Leases, Future Minimum Payments, Due in Four Years 2016 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Unrecorded Unconditional Purchase Obligation [Abstract] Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract] 2012 Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months 2013 Unrecorded Unconditional Purchase Obligation, Due within Two Years 2014 Unrecorded Unconditional Purchase Obligation, Due within Three Years 2015 Unrecorded Unconditional Purchase Obligation, Due within Four Years 2016 Unrecorded Unconditional Purchase Obligation, Due within Five Years Thereafter Unrecorded Unconditional Purchase Obligation, Due after Five Years Total Unrecorded Unconditional Purchase Obligation, Total Unrecorded Unconditional Purchase Obligation, Total Schedule of Finite-Lived Intangible Assets by Major Class [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Useful life, minimum Finite-Lived Intangible Asset, Useful Life Taxes on income Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Reconciliation of the statutory U.S. federal income tax rate to the effective tax rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Deferred tax assets (liabilities) Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Unrecognized tax benefits Summary of Income Tax Contingencies [Table Text Block] Reconciliation of unrecognized tax benefits Reconciliation Of Unrecognized Tax Benefits [Text Block] Reconciliation Of Unrecognized Tax Benefits Statement of Financial Position Parentheticals [Abstract] Statement of Financial Position Parentheticals [Abstract] Series B Preferred Stock [Member] SeriesAJuniorParticipatingPreferredStock [Member] SeriesAJuniorParticipatingPreferredStock [Member] Allowance for Doubtful Accounts Receivable Allowance for Doubtful Accounts Receivable Restricted Cash and Cash Equivalents, Current Restricted Cash and Cash Equivalents, Current Restricted Cash and Cash Equivalents, Noncurrent Restricted Cash and Cash Equivalents, Noncurrent Preferred Stock, Par or Stated Value Per Share Preferred Stock, Par or Stated Value Per Share Preferred Stock, Shares Authorized Preferred Stock, Shares Authorized Preferred Stock, Shares Issued Preferred Stock, Shares Issued Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding Common Stock, Shares, Issued Common Stock, Shares, Issued Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Share-based compensation arrangement by share-based payment award, number of shares reserved Share-based compensation arrangement by share-based payment award, number of shares authorized Vesting percentage after one year Vesting Percentage After One Year Vesting percentage after one year Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Employee service share-based compensation, unrecognized compensation costs on nonvested awards, Weighted Average Period of Recognition, years Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Stock options, granted, shares Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Share-based compensation arrangement by share-based payment award, options, exercises in period, total intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value Share-based compensation arrangement by share-based payment award, vesting period lower range Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period Lower Range Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period Lower Range Share-based compensation arrangement by share-based payment award, vesting period upper range Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period Upper Range Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period Upper Range Granted performance shares Share Based Compensation Arrangement by Share Based Payment Award Performance Shares Grants in Period Share Based Compensation Arrangement by Share Based Payment Award Performance Shares Grants in Period Granted performance shares, value Share Based Compensation Arrangement by Share Based Payment Award Performance Shares Grants in Period, Value Share Based Compensation Arrangement by Share Based Payment Award Performance Shares Grants in Period, Value Restricted Class A common stock, fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value Total expense for stock payments Share-based compensation arrangement by share-based payment award, discount from market price Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date Class A common stock issued to participating employees Class A Common Stock Issued To Participating Employees Class A common stock issued to participating employees Annual award of class A common stock value Annual Award Of Class A Common Stock Value Annual award of class A common stock value Annual stipend allowance in shares of stock Annual Stipend Allowance In Shares Of Stock Annual stipend allowance in shares of stock Annual stipend allowance in shares of stock (in shares) Annual Stipend Allowance In Shares Of Stock (In Shares) Annual stipend allowance in shares of stock (in shares) Share-based compensation arrangements expected life Share-based compensation arrangements expected life Share-based compensation arrangements expected life Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Line Items] Subsequent Event [Line Items] Comprehensive Income (Loss) Note [Text Block] Comprehensive Income (Loss) Note [Text Block] Debt Debt Disclosure [Text Block] current [Member] current [Member] current [Member] Noncurrent [Member] Noncurrent [Member] Noncurrent [Member] Net Current Deferred Tax Assets Deferred Tax Assets, Net of Valuation Allowance, Current Domestic unrealized loss on investment in BM&FBOVESPA Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Impairment Losses Deferred tax asset Domestic Losses Deferred tax asset Domestic Losses Deferred tax asset Domestic Losses Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Other Unrealized loss on securities Deferred Tax Assets, Unrealized Losses on Trading Securities Accrued expenses and other Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Subtotal Valuation allowance Total non-current deferred tax assets Deferred Tax Assets, Net of Valuation Allowance, Noncurrent Purchase intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets Property Deferred Tax Liabilities, Property, Plant and Equipment Total non-current deferred tax liabilities Deferred Tax Liabilities, Net, Noncurrent Net Non-Current Deferred Tax Liabilities Earnings Per Share Earnings Per Share [Text Block] Commitments Commitments Disclosure [Text Block] 2014 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2015 Long-term Debt, Maturities, Repayments of Principal in Year Two 2016 Long-term Debt, Maturities, Repayments of Principal in Year Three 2017 Long-term Debt, Maturities, Repayments of Principal in Year Four 2018 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Income before income taxes: Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Income before income taxes: Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Current income tax provision: Federal Current Federal Tax Expense (Benefit) Current income tax provision: State Current State and Local Tax Expense (Benefit) Current income tax provision: Foreign Current Foreign Tax Expense (Benefit) Current income tax provision: Total Current Income Tax Expense (Benefit) Deferred income tax provision: Federal Deferred Federal Income Tax Expense (Benefit) Deferred income tax provision: State Deferred State and Local Income Tax Expense (Benefit) Deferred income tax provision: Foreign Deferred Foreign Income Tax Expense (Benefit) Deferred income tax provision: Total Total Income Tax Provision Changes in redeemable non-controlling interest Redeemable Noncontrolling Interest [Table Text Block] Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock Options [Member] Stock Options [Member] Restricted Stock [Member] Restricted Stock [Member] Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Domain] Option Indexed to Issuer's Equity, Type [Domain] Dilutive Securities, Effect on EPS Dilutive Securities, Effect on EPS Dilutive Securities, Effect on EPS Diluted Earnings per common share, basic Earnings per common share, diluted Outstanding anti-dilutive options Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Interest Rate Cash Flow Hedge Derivative at Fair Value, Net Gross unrecognized tax benefits Unrecognized tax benefits, net of tax impacts in other jurisdictions Unrecognized Tax Benefits Net Of Tax Impacts In Other Jurisdictions Unrecognized Tax Benefits Net Of Tax Impacts In Other Jurisdictions Interest and penalties related to uncertain tax positions Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Interest and penalties recognized in the consolidated statements of income Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Concentration Risk by Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Clearing and transaction fees from Firm 1 Sales Revenue, Clearing and Transaction Fees, Firm One [Member] Sales Revenue, Clearing and Transaction Fees, Firm One [Member] Clearing and transaction fees from Firm 2 Sales Revenue, Clearing and Transaction Fees, Firm Two [Member] Sales Revenue, Clearing and Transaction Fees, Firm Two [Member] Market data and information services Sales Revenue, Market Data and Information Services [Member] Sales Revenue, Market Data and Information Services [Member] Concentration Risk, Customer Concentration Risk, Customer Estimated useful live of the assets minimum in years Concentration of revenue Concentration Risk, Percentage Fair Value Measurements Fair Value Disclosures [Text Block] Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis] Fair Value Plan Asset Measurement [Domain] Defined Benefit Plan, Fair Value of Plan Assets Defined Benefit Plan, Fair Value of Plan Assets Property Property, Plant and Equipment Disclosure [Text Block] Quarterly Information Schedule of Quarterly Financial Information [Table Text Block] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Balance at January 1 Actual return on plan assets Defined Benefit Plan, Actual Return on Plan Assets Employer contributions Defined Benefit Plan, Contributions by Employer Benefits paid Balance at December 31