Document and Entity Information [Abstract] Document and Entity Information [Abstract] Statement [Table] Class of Stock [Axis] Class of Stock [Domain] Class A Common Stock (Shares) Class A Common Stock (Shares) Class B Common Stock, Class B1 [Member] Class B Common Stock, Class B1 Class B Common Stock, Class B2 [Member] Class B Common Stock, Class B2 Class B Common Stock, Class B3 [Member] Class B Common Stock, Class B3 Class B Common Stock, Class B4 [Member] Class B Common Stock, Class B4 Statement [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Period Focus Document Fiscal Year Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Common Stock, Shares Outstanding Statement of Financial Position Preferred stock Series A junior participating preferred stock Class B Common Stock (Shares) Class B Common Stock (Shares) Assets Cash and cash equivalents Cash and Cash Equivalents, End of Period Cash and cash equivalents, beginning of period Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value, Total Marketable Securities, Current Marketable securities Marketable Securities, Current, Total Marketable securities Accounts receivable, net of allowance of $1.4 and $1.9 Accounts Receivable, Net, Current, Total Accounts receivable, net of allowance of $1.0 and $1.9 Other Assets, Current Other current assets Other current assets Total Good Faith and Margin Deposits with Broker-Dealers Cash performance bonds and security deposits Total current assets Total current assets Property, net Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Property, net Property, net Property, net of accumulated depreciation and amortization of $572.0 and $546.1 Intangible assets - trading products Intangible assets - other, net Intangible Assets, Net (Excluding Goodwill), Total Net book value Goodwill Total goodwill, ending balance Total goodwill, beginning balance Other Assets, Noncurrent Total Other Assets, Noncurrent, Total Other assets Total Assets Total Assets Liabilities and Shareholders' Equity Accounts Payable, Current Accounts Payable, Current, Total Accounts payable Short-term debt $300.0 million floating rate notes due August 2010, interest equal to 3-month LIBOR plus 0.65%, reset quarterly Other Liabilities Current Total Other Liabilities, Current, Total Other current liabilities 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). Cash Performance Bonds and Security Deposit Liability Cash performance bonds and security deposits Total current liabilities Total current liabilities Long-term debt Long-term debt Net Non-Current Deferred Tax Liabilities Deferred tax liabilities, net Deferred tax liabilities, net Other Liabilities Noncurrent Total Other Liabilities, Noncurrent, Total Other liabilities Total Liabilities Total Liabilities Redeemable non-controlling interest Shareholders' Equity: Preferred Stock, Value, Issued Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued, Beginning Balance Preferred stock, $0.01 par value, 9,860 shares authorized, none issued or outstanding Preferred Stock, Value, Issued, Total Preferred stock, $0.01 par value, 9,860 shares authorized, none issued or outstanding Series A junior participating preferred stock, $0.01 par value, 140 shares authorized, none issued or outstanding Series Junior Participating Preferred Stock Series A junior participating preferred stock, $0.01 par value, 140 shares authorized, none issued or outstanding Class A common Class A common Class A common stock, $0.01 par value, 1,000,000 shares authorized, 66,793 and 66,511 shares issued and outstanding as of September 30, 2010 and December 31, 2009 Class A common stock, $0.01 par value, 1,000,000 shares authorized, 66,511 and 66,417 shares issued and outstanding as of December 31, 2009 and 2008, respectively Class A common stock, $0.01 par value, 1,000,000 shares authorized, 0 and 66,511 shares issued and outstanding as of June 30, 2010 and December 31, 2009 Class B common stock, $0.01 par value, 3 shares authorized, issued and outstanding Additional paid-in capital Additional Paid in Capital, Common Stock, Ending Balance Additional Paid in Capital, Common Stock, Beginning Balance Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Total Retained earnings Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive income (loss) Total Shareholders' Equity Balance Balance Balance Total Shareholders' Equity Total Liabilities and Shareholders' Equity Total Liabilities and Shareholders' Equity Accounts receivable, allowance Allowance for Doubtful Accounts Receivable, Current, Ending Balance Allowance for Doubtful Accounts Receivable, Current, Beginning Balance Accounts receivable, allowance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance Property, accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Total Less accumulated depreciation and amortization Preferred stock, par value Preferred stock, shares authorized Preferred stock, issued Preferred stock, shares issued Preferred Stock, Shares Issued, Total Preferred stock, outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, shares outstanding Common stock, par value Common stock, shares authorized Shares authorized Common stock, shares issued Common Stock, Shares, Issued, Total Common stock, shares outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common Stock Income Statement Revenues Fees earned by providing executing servicing and clearing, net of rebates. Clearing And Execution Servicing Clearing and transaction fees Market Data And Information Services Market data and information services Revenue from providing access fees to customers for the use of electronic trading platform and revenue from telecommunication networks and communication services. Access and communication fees Other Sales Revenue, Net Other Total Revenues Total Revenues Expenses Compensation and benefits Labor and Related Expense, Total Communications Technology support services Professional fees and outside services Amortization of purchased intangibles Total amortization expense for intangible assets Amortization of Intangible Assets, Total Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction, Total Occupancy and building operations Licensing and other fee agreements Restructuring Charges Restructuring expense Restructuring Charges, Total Restructuring Other Cost and Expense, Operating Other Cost and Expense, Operating, Total Other Total Expenses Total Expenses Operating Income Operating Income Non-Operating Income (Expense) Investment income Investment Income, Nonoperating, Total Impairment of long-term investment Impairment of long-term investment Investment impairment charges Impairment loss on invested collateral due Gains (losses) on derivative investments Gains (losses) on derivative investments Gain (Loss) on Derivative Instruments, Net, Pretax, Total Net loss on derivative investments Securities lending interest income (interest earned on collateral received through the securities lending program). Securities lending interest income Securities lending interest expense (rebate expense paid back to security borrowers in the securities lending program derived from collateral investment). Securities Lending Interest Expense Securities lending interest and other costs SecuritiesLendingInterestExpense Securities lending interest and other costs Interest and other borrowing costs Interest and other borrowing costs Interest and Debt Expense, Total Equity in losses of unconsolidated subsidiaries Equity in losses of unconsolidated subsidiaries Income (Loss) from Equity Method Investments, Total Equity in losses of unconsolidated subsidiaries Other income (expense) Other Nonoperating Income (Expense), Total Total Non-Operating Total Non-Operating Non-operating income (expense) Sum of operating profit and nonoperating income (expense) before income taxes. Income Loss From Continuing Operations Before Income Taxes Income before Income Taxes Income before income taxes Total Income Tax Provision Income Tax Expense (Benefit), Total Income Tax Expense (Benefit), Total Income tax provision Net Income Loss Net income Net Income Net Income Less: net income attributable to redeemable non-controlling interest Net income (loss) for the period Net Income (Loss) Attributable to Noncontrolling Interest, Total Net income attributable to CME Group Net income Net Income Attributable to CME Group Net Income Attributable to CME Group Earnings per Common Share Attributable to CME Group: Earnings per Common Share Attributable to CME Group: Earnings Per Share, Basic Earnings per common share, basic Earnings Per Share, Basic, Total Basic Earnings Per Share, Diluted Earnings per common share, diluted Earnings Per Share, Diluted, Total Diluted Weighted Average Number of Common Shares: Weighted Average Number Of Shares Outstanding, Basic Weighted average number of common shares, basic Weighted Average Number of Shares Outstanding, Basic, Total Basic Weighted Average Number Of Shares Outstanding, Diluted Weighted average number of common shares, diluted Weighted Average Number of Shares Outstanding, Diluted, Total Diluted Statement of Stockholders' Equity Statement, Equity Components [Axis] Equity Component [Domain] Common Stock and Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Number of shares of stock held by shareholders. Shares, Outstanding Balance (in shares) Balance (in shares) Balance (in shares) Comprehensive income: Change in net unrealized loss on securities, net of tax Change in net unrealized loss on securities, net of tax $1.2, 16.4, 16.5 respectively in 2007, 2008 and 2009 Change in net unrealized loss on securities, net of tax Change in net actuarial loss on defined benefit plans, net of tax Change in net actuarial loss on defined benefit plans, net of tax of $1.6, 10.4, 0.9 respectively in 2007, 2008 and 2009 Other Comprehensive Income, Defined Benefit Plans Adjustment, Net of Tax, Total Change in net actuarial loss on defined benefit plans, net of tax Change in net unrealized loss on derivatives, net of tax Change in net unrealized loss on derivatives, net of tax of $13.5 and 4.7 respectively in 2008 and 2009 Change in net unrealized loss on derivatives, net of tax Change in net unrealized loss on derivatives, net of tax Change in foreign currency translation adjustment Change in foreign currency translation adjustment, net of tax of $0.3, 21.3, 1.7 respectively in 2007, 2008 and 2009 Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total Change in foreign currency translation adjustment, net of tax Total comprehensive income attributable to CME Group Total comprehensive income Total comprehensive income attributable to CME Group Cash dividend on common stock of $4.60 per share in 2009, $9.60 per share in 2008 and $3.44 per share in 2007 Cash dividend on common stock of $4.60 per share in 2009, $9.60 per share in 2008 and $3.44 per share in 2007 Cash dividend on common stock of $1.15 per share Cash dividends on common stock of $4.60 per share in 2009, $9.60 per share in 2008 and $3.44 per share in 2007 Dividends, Cash, Total Cash dividends on common stock of $3.45 per share Stock issued during period, shares to partner exchange Stock Issued During Period Shares To Partner Exchange Class A common stock issued to BM&FBOVESPA (in shares) Stock issued during period to partner exchange Stock Issued During PeriodTo Partner Exchange Class A common stock issued to BM&FBOVESPA Repurchase of Class A common stock (in shares) Number of Share Repurchased Repurchase of Class A common stock Repurchase of Class A common stock Total of Share Repurchased Exercise of stock options (in shares) Exercise of stock options Excess tax benefits from option exercises and restricted stock vesting Number of shares issued during the period as a result of the vesting of restricted stock units. Vesting Of Issued Restricted Stock Vesting of issued restricted Class A common stock (in shares) Vesting Of Issued Restricted Stock Vesting Of Issued Restricted Stock Value Vesting of issued restricted Class A common stock Number of shares of stock issued during the period to related parties. Stock Issued To Related Parties During Period Shares Shares issued to Board of Directors (in shares) Value of stock issued during the period to related parties. Stock Issued To Related Parties During Period Value Shares issued to Board of Directors Shares issued under Employee Stock Purchase Plan (in shares) Shares issued under Employee Stock Purchase Plan (in shares) Shares issued under Employee Stock Purchase Plan Shares issued under Employee Stock Purchase Plan Stock Granted During Period, Value, Share-based Compensation Stock-based compensation Change in net unrealized loss on securities, tax Change in net actuarial loss on defined benefit plans, tax Other Comprehensive Income, Defined Benefit Plans, Tax, Total Change in net unrealized loss on derivatives, tax Change in foreign currency translation adjustment, tax Other Comprehensive Income, Foreign Currency Translation Adjustment, Tax, Total Cash dividends on common stock, per share Statement of Cash Flows Cash Flows from Operating Activities Adjustments to reconcile net income to net cash provided by operating activities: Share-based Compensation Share-based Compensation, Total Stock-based compensation Credit Market Analysis Limited impairment Net accretion of discounts and amortization of debt financing costs Amortization of Financing Costs and Discounts, Total Deferred Income Tax Expense Benefit Deferred income taxes Deferred income tax provision: Total Change in assets and liabilities: Accounts receivable Accounts receivable Other current assets Other current assets Increase (Decrease) in Prepaid, Deferred Expense and Other Assets, Total Increase Decrease In Other Operating Assets Other assets Accounts payable Increase (Decrease) in Accounts Payable, Total Accounts payable Income tax payable Income taxes payable Other current liabilities Other current liabilities Other liabilities Other liabilities Adjustments Noncash Items To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities Other Other Net Cash Provided by Operating Activities Net Cash Provided by Operating Activities Cash Flows from Investing Activities Proceeds from maturities of available-for-sale marketable securities Purchases of available-for-sale marketable securities Purchases of available-for-sale marketable securities Payments to Acquire Available-for-sale Securities, Total Net change in NYMEX securities lending program investments Net change in NYMEX securities lending program investments Payments for (Proceeds from) Investments, Total Purchases of property, net Purchases of property, net Payments to Acquire Property, Plant, and Equipment, Total Cash acquired from Index Services Cash acquired in formation of Index Services Payments for (Proceeds from) Businesses and Interest in Affiliates, Total Proceeds From Exercise Right Privileges Proceeds From Exercise Right Priveleges Proceeds from Chicago Board Options Exchange exercise right privileges Payments to Acquire Equity Method Investments Purchase of Bolsa Mexicana de Valores, S.A.B. de C.V. shares Purchase of Bolsa Mexicana de Valores, S.A.B. de C.V. shares Capital contributions to FXMarketSpace Limited Capital contributions to FXMarketSpace Limited Payments to Acquire Interest in Subsidiaries and Affiliates, Total Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities Repayments of commercial paper, net of proceeds Proceeds from (Repayments of) Other Debt, Total Proceeds from other borrowings, net of issuance costs Repayment of other borrowings Repayment of other borrowings Net change in securities lending program liability. Net Change In Securities Lending Program Liability Net change in NYMEX securities lending program liabilities Cash dividends Cash dividends Payments of Dividends, Total Common stock issued to partner exchange Common Stock Issued To Partner Exchange Class A common stock issued to BM&FBOVESPA PaymentsForRepurchase Of Common Stock Repurchase of Class A common stock, including costs Treasury Stock, Shares Treasury Stock, Shares Treasury Stock, Value Proceeds from exercise of stock options Distribution paid to non-controlling interest Distribution paid to non-controlling interest Excess tax benefits related to employee option exercises and restricted stock vesting Other Other Net Cash Used in Financing Activities Net Cash Used in Financing Activities Net change in cash and cash equivalents Net change in cash and cash equivalents Supplemental Disclosure of Cash Flow Information Income taxes paid Interest paid (excluding securities lending program) Cash Flow, Noncash Investing Disclosure [Abstract] Cash Flow Noncash Investing Disclosure Abstract Non-cash investing activities: Change in net unrealized securities gains (losses) Other Comprehensive Income, Available-for-sale Securities Adjustment, before Tax, Total Change in net unrealized derivatives gains (losses) Basis of Presentation [Abstract] Basis of Presentation Organization Consolidation and Presentation of Financial Statements Disclosure [Text Block] Basis of Presentation Business Combinations [Abstract] Business Combinations Business Combination Disclosure [Text Block] Business Combinations Intangible Assets and Goodwill [Abstract] Intangible Assets and Goodwill Goodwill and Intangible Assets Disclosure [Text Block] INTANGIBLE ASSETS AND GOODWILL Intangible Assets and Goodwill Debt [Abstract] Debt Debt Disclosure [Text Block] Debt Contingencies Schedule of Loss Contingencies by Contingency [Text Block] Contingencies Guarantees [Abstract] Guarantees Schedule of Guarantee Obligations [Text Block] Guarantees Stock-Based Payments Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Stock-Based Payments Fair Value Measurements Fair Value Disclosures Text Block Fair Value Measurements Earnings Per Common Share [Abstract] Earnings Per Common Share Earnings Per Share [Text Block] Earnings Per Common Share Subsequent Events [Abstract] Subsequent Events Schedule of Subsequent Events [Text Block] Subsequent Events Changes in redeemable non-controlling interest Changes in redeemable non-controlling interest [Text Block] Changes in redeemable non-controlling interest Summarizes Total Comprehensive Income Attributable To Redeemable Non-controlling Interest Summarizes Total Comprehensive Income Attributable To Redeemable Non-controlling Interest Text Block Summarizes total comprehensive income attributable to redeemable non-controlling interest Intangible Assets Disclosure [Text Block] Components of intangible assets Future Estimated Amortization Expense [Text Block] Future Estimated Amortization Expense [Text Block] Future estimated amortization expense Schedule of Goodwill [Text Block] Goodwill activity Schedule Of Short Term And Long Term Debt [Text Block] Schedule Of Short Term And Long Term Debt [Text Block] Schedule of short-term and long-term debt Long Term Debt Maturities At Par Value [Text Block] Long Term Debt Maturities At Par Value [Text Block] Long-term debt maturities at par value Fair Value Of Fixed Rate Notes By Maturity Date [Text Block] Fair Value Of Fixed Rate Notes By Maturity Date [Text Block] Fair value of fixed rate notes by maturity date Fair Value Measurement Inputs Disclosure [Text Block] Financial instruments measured at fair value on a recurring basis Basic And Diluted Earnings Per Share [Text Block] Basic And Diluted Earnings Per Share [Text Block] Basic and diluted earnings per share Noncontrolling Interest, Ownership Percentage by Parent Ownership in Index Services Acquired Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Index services intangible assets total [Member] Index Services Intangible Assets Total [Member] Index Services Customer Relationships [Member] Trade Names [Member] Index services goodwill [Member] Index Services Goodwill [Member] Indefinite-lived Intangible Assets by Major Class [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Other - Indefinite [Member] Goodwill, Acquired During Period Business Combinations Acquired intangible asset amount total index services Aquired intangible asset amount total index services Acquired intangible asset amount total index services Acquired finite lived intangible asset amount - customer relationships Acquired Finite Lived Intangible Asset Amount - Customer Relationships Acquired finite lived intangible asset amount - customer relationships Acquired Finite Lived Intangible Asset Amount Trade Name Acquired Finite Lived Intangible Asset Amount Trade Name Fixed Rate Notes Fixed Rate Notes Fixed rate notes Fixed Rate Percentage On Notes Fixed Rate Percentage On Notes Fixed rate percentage on notes Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Redeemable Common Stock Carrying Amount Redeemable Common Stock Carrying Amount Balance at September 30, 2010 Balance at December 31, 2009 Contribution by redeemable noncontrolling interest Contribution by redeemable noncontrolling interest Contribution by Dow Jones Distribution to redeemable noncontrolling interest Distribution to redeemable noncontrolling interest Distribution to Dow Jones Net income loss attributable to redeemable noncontrolling interest Net income loss attributable to redeemable noncontrolling interest Net income (loss) for the period Other Comprehensive Income Unrealized Gain Loss On Derivatives Attributable To Redeemable Non Controlling Interest Other Comprehensive Income Unrealized Gain Loss On Derivatives Attributable To Redeemable Non Controlling Interest Net unrealized loss on derivative related to 4.40% fixed rate notes Comprehensive income net of tax attributable to redeemable noncontrolling interest Comprehensive income net of tax attributable to redeemable noncontrolling interest Total comprehensive income attributable to redeemable non-controlling interest Total comprehensive income attributable to redeemable non-controlling interest Finite-Lived Intangible Assets by Major Class [Axis] Clearing firm, market data, and other customer relationships [Member] Lease-related intangibles [Member] Dow Jones trading products [Member] Technology-related intellectual property [Member] Open Interest [Member] Open interest [Member] Other - Finite [Member] Other - Finite [Member] Total amortizable intangible assets [Member] Total amortizable intangible assets [Member] Total amortizable intangible assets, net [Member] Total Amortizable Intangible Assets, Net [Member] Indefinite-lived Trading Products (a) [Member] Indefinite-Lived Trading Products [Member] Indefinite-lived Trading Products (a) [Member] Foreign Currency Translation Adjustments [Member] Foreign currency translation adjustments [Member] Foreign currency translation adjustments indefinite [Member] Foreign currency translation adjustments indefinite [Member] Total Indefinite-Lived Intangible Assets [Member] Total Indefinite-Lived Intangible Assets [Member] Goodwill by Segment [Axis] Goodwill, Segment [Domain] CBOT Holdings [Member] CBOT holdings [Member] NYMEX Holdings [Member] NYMEX holdings [Member] CMA [Member] CMA [Member] Index Services [Member] Index Services [Member] Impairment of Intangible Assets (Excluding Goodwill) Impairment Charge Impairment of Intangible Assets (Excluding Goodwill), Total Goodwill, Impairment Loss Impairment Adjustments Finite-Lived Intangible Assets, Gross Cost Cost Finite-Lived Intangible Assets, Accumulated Amortization Accumulated amortization Accumulated amortization Finite-Lived Intangible Assets, Net Net book value Finite-Lived Intangible Assets, Net, Total Future Estimated Amortization Remainder Of Current Year Future Estimated Amortization Remainder Of Current Year Remainder of 2010 Future Amortization Expense, Year One 2011 Future Amortization Expense, Year Two 2012 Future Amortization Expense, Year Three 2013 Future Amortization Expense, Year Four 2014 Future Amortization Expense, Year Five 2015 Future Estimated Amortization Year Six And Thereafter Future Estimated Amortization Year Six And Thereafter Thereafter Goodwill, Translation and Purchase Accounting Adjustments Other activity Debt Instrument [Axis] Debt Instrument, Name [Domain] Floating Rate Notes Due August 2010 [Member] Floating rate notes due August 2010 [Member] Term Loan Due 2011 [Member] Term loan due 2011 [Member] Total Short-Term Debt [Member] Total Short-Term Debt [Member] Fixed Rate Notes Due August 2013 [Member] Fixed rate notes due August 2013 [Member] Fixed Rate Notes Due February 2014 [Member] Fixed rate notes due February 2014 [Member] Fixed Rate Notes Due March 2018 [Member] Fixed rate notes due March 2018 [Member] Long-term Debt, Percentage Bearing Fixed Interest Rate Short-term Debt, Percentage Bearing Variable Interest Rate Long-term Debt, Percentage Bearing Variable Interest Rate Debt Instrument, Face Amount Commercial Paper Maturity Date Range Start Commercial Paper Maturity Date Range Start Commercial paper maturity date range start Commercial Paper Maturity Date Range End Commercial Paper Maturity Date Range End Commercial paper maturity date range end Commercial Paper Weighted Average Discount Rates Commercial Paper Weighted Average Discount Rates Commercial paper weighted average discount rates Commercial Paper Weighted Average Balance At Par Value Commercial Paper Weighted Average Balance At Par Value Commercial paper weighted average balance at par value Interest swap rate agreement, fixed rate Interest swap rate agreement fixed rate Interest swap rate agreement 2008 fixed rate Forward starting interest rate swap agreement, fixed rate Forward starting interest rate swap agreement fixed rate Forward starting interest rate swap agreement 2010 fixed 4.46% Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash Equivalents [Member] Commercial paper [Member] Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term debt, maturities, repayments of principal in 2011 Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term debt, maturities, repayments of principal in 2012 Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term debt, maturities, repayments of principal in 2013 Long-term Debt, Maturities, Repayments of Principal in Year Five Long-term debt, maturities, repayments of principal in 2014 Amount of long-term debt maturing in year six following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates. Long Term Debt Maturities Repayments Of Principal In Year Six Long-term debt, maturities, repayments of principal in 2015 Long-term Debt, Maturities, Repayments of Principal after Year Five Thereafter Fair Value Of Fixed Rate Notes Due August 2013 [Member] Fair value of fixed rate notes due August 2013 [Member] Fair Value Of Fixed Rate Notes Due February 2014 [Member] Fair value of fixed rate notes due February 2014 [Member] Fair Value Of Fixed Rate Notes Due March 2018 [Member] Fair value of fixed rate notes due March 2018 [Member] Debt Instrument, Fair Value Debt instrument, fair value Performance Bonds And Security Deposits [Abstract] Performance Bonds And Security Deposits [Abstract] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency, Nature [Domain] Guarantee Obligations [Member] Financial Standby Letter of Credit [Member] Daily Transfer Between Clearing Firms Daily Transfer Between Clearing Firms Daily transfers between clearing firms Guarantor Obligations, Maximum Exposure, Undiscounted Contingent liability to SGX, amount of irrevocable letters of credit Percentage allocated to parent and external party of cross-margin arrangement of gains (losses) on liquidation of open position and cross-margin account Percentage Allocated To Parent And External Party Of Cross Margin Arrangement Of Gains Losses On Liquidation Of Open Position And Cross Margin Account Percentage allocated to CME and OCC of gains (losses) on liquidation of open position and cross margin account Guarantor Obligations, Current Carrying Value Guarantor obligations, current carrying value Legal Entity [Axis] Entity [Domain] Range Maximum Range Maximum [Member] Range Minimum Range Minimum [Member] Allocated Share-based Compensation Expense Total expense for stock payments Allocated Share-based Compensation Expense, Total Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Income tax benefit for stock-based payment arrangements Share Based Compensation Arrangement By Share-based Payment Award Options Grants In Period Number of shares awarded Number of shares granted Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Dating Stock options, term in years Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Grant Date Fair Value Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Grant Date Fair Value Share based compensation arrangement by share based payment award options grants in period grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Stock option valuation assumption, dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Stock option valuation assumption, expected volatility Stock option valuation assumption, risk-free interest rate Stock option valuation assumption, risk-free interest rate, Lower Range Limit Stock option valuation assumption, risk-free interest rate Stock option valuation assumption, risk-free interest rate, Upper Range Limit Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Stock option valuation assumption, expected life 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 Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Grant date weighted average fair value of options granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Grants of restricted Class A common stock, shares Share Based Compensation Arrangement By Share Based Payment Award Restricted Stock Units Grants In Period Share Based Compensation Arrangement By Share Based Payment Award Restricted Stock Units Grants In Period Grants of restricted stock units 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, award vesting period lower 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 Share based compensation arrangement by share based payment award, award vesting period upper range Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value Restricted Class A common stock, fair value Notes to Financial Statements [Abstract] Notes to Financial Statements [Abstract] Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis] Fair Value Plan Asset Measurement [Domain] Fair Value, Inputs, level 1 [Member] Fair Value, Inputs, level 2 [Member] Fair Value, Inputs, level 3 [Member] U.S. Treasury securities [Member] Schedule of Trading Securities and Other Trading Assets, Major Types of Trading Securities and Assets [Axis] Major Types of Trading Securities and Assets [Domain] Total marketable securities [Member] Debt Securities [Member] Corporate Debt Securities [Member] Corporate bonds [Member] Asset-backed securities [Member] U.S. Government agency securities [Member] Equity investments [Member] Parent [Member] Fair value, measured on recurring basis, investments Total Assets at Fair Value Fair value, liabilities measured on recurring basis, derivative financial instruments, liabilities Interest Rate Swaps Total Liabilities At Fair Value Total liabilities at fair value Fair Value Goodwill Impairment Test Fair Value Goodwill Impairment Test Fair Value Trade Name Impairment Test Fair Value Trade Name Impairment Test Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Restricted stock [Member] Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Domain] Employee stock option [Member] Restricted Stock Awards [Member] Restricted stock awards [Member] Antidilutive Securities Excluded From Computation Of Earnings Per Share, Amount Effect of restricted grants Incremental Common Shares Attributable To Share-Based Payment Arrangements Effect of restricted stock awards Incremental Common Shares Attributable to Share-based Payment Arrangements, Total Commitments and Contingencies Disclosure [Text Block] Loss Contingencies [Table] Mutual Funds [Member] Mutual funds [Member] Fixed Income Securities [Member] Municipal bonds [Member]