CME (CME) 10-Q 6 May 20 2020 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2020	Apr. 15, 2020
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-31553
Entity Registrant Name	CME GROUP INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-4459170
Entity Address, Street Address	20 South Wacker Drive
Entity Address, City	Chicago
Entity Address, State	IL
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	930-1000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of each class	Class A Common Stock
Trading symbol	CME
Name of each exchange on which registered	NASDAQ
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001156375
Amendment Flag	false
Class A Common Stock [Member]
Entity Common Stock, Shares Outstanding		358,585,174
Class B Common Stock, Class B-1 [Member]
Entity Common Stock, Shares Outstanding		625
Class B Common Stock, Class B-2 [Member]
Entity Common Stock, Shares Outstanding		813
Class B Common Stock, Class B-3 [Member]
Entity Common Stock, Shares Outstanding		1,287
Class B Common Stock, Class B-4 [Member]
Entity Common Stock, Shares Outstanding		413

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents		$ 851.7	$ 1,551.4
Marketable securities		77.5	83.2
Accounts receivable, net of allowance of $4.8 and $3.4		799.7	491.8
Other current assets (includes $4.3 and $4.3 in restricted cash)		315.9	364.4
Performance bonds and guaranty fund contributions		100,371.8	37,077
Total current assets		102,416.6	39,567.8
Property, net of accumulated depreciation and amortization of $885.6 and $867.5		538.4	544
Intangible assets, trading products	[1]	17,175.3	17,175.3
Intangible assets—Other, net		4,997.9	5,117.7
Goodwill		10,742.5	10,742.5
Other assets (includes $0.8 and $0.9 in restricted cash)		2,061.6	2,068
Total Assets		137,932.3	75,215.3
Liabilities and Equity
Accounts payable		74.3	61.9
Other current liabilities		607.9	1,384.8
Performance bonds and guaranty fund contributions		100,371.5	37,075.8
Total current liabilities		101,053.7	38,522.5
Long-term debt		3,539.8	3,743.2
Deferred income tax liabilities, net		5,622.1	5,635.2
Other liabilities		1,118	1,155.1
Total Liabilities		111,333.6	49,056
Shareholders' Equity:
Preferred stock, $0.01 par value, 10,000 shares authorized at March 31, 2020 and December 31, 2019; none issued		0	0
Additional paid-in capital		21,120.4	21,113.2
Retained earnings		5,469.9	5,008.7
Accumulated other comprehensive income (loss)		(26.2)	3.4
Total CME Group Shareholders’ Equity		26,567.7	26,128.9
Stockholders' Equity Attributable to Noncontrolling Interest		31	30.4
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		26,598.7	26,159.3
Total Liabilities and Equity		137,932.3	75,215.3
Class A Common Stock [Member]
Shareholders' Equity:
Common stock		3.6	3.6
Class B Common Stock [Member]
Shareholders' Equity:
Common stock		$ 0	$ 0
[1]	) Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the Commodity Futures Trading Commission (CFTC). Product authorizations from the CFTC have no term limits.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accounts receivable, allowance	$ 4.8	$ 3.4
Short-term restricted cash	4.3	4.3
Accumulated depreciation and amortization, property	885.6	867.5
Long-term restricted cash	$ 0.8	$ 0.9
Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000	10,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares issued (in shares)	357,677	357,469
Common stock, shares outstanding (in shares)	357,677	357,469
Class B Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	3	3
Common stock, shares issued (in shares)	3	3
Common stock, shares outstanding (in shares)	3	3

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues
Total Revenues	$ 1,522.1	$ 1,179.6
Expenses
Compensation and benefits	207.5	230.3
Technology	47.7	47.1
Professional fees and outside services	41.7	39.4
Amortization of purchased intangibles	77.3	80.7
Depreciation and amortization	35.3	32.9
Licensing and other fee agreements	73.9	40.5
Other	78.8	77.7
Total Expenses	562.2	548.6
Operating Income	959.9	631
Non-Operating Income (Expense)
Investment income	95.9	178.7
Interest and other borrowing costs	(40.9)	(48.1)
Equity in net earnings of unconsolidated subsidiaries	51.2	40.5
Other non-operating income (expense)	(76.8)	(161.9)
Total Non-Operating Income (Expense)	29.4	9.2
Income before Income Taxes	989.3	640.2
Income tax provision	222.5	144.3
Net Income	766.8	495.9
Net (Income) Loss Attributable to Noncontrolling Interest	(0.6)	1
Net Income (Loss) Attributable to CME Group	$ 766.2	$ 496.9
Earnings per Common Share Attributable to CME Group:
Basic (in dollars per share)	$ 2.14	$ 1.39
Diluted (in dollars per share)	$ 2.14	$ 1.39
Weighted Average Number of Common Shares:
Basic (in shares)	357,524	356,886
Diluted (in shares)	358,455	358,047
Clearing and transaction fees [Member]
Revenues	$ 1,278.8	$ 952.6
Market data and information services
Revenues	131.5	130.1
Other
Revenues	$ 111.8	$ 96.9

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 766.8	$ 495.9
Other comprehensive income (loss), net of tax:
Net unrealized holding gains (losses) arising during the period	(0.6)	0.8
Income tax benefit (expense)	0.2	(0.2)
Investment securities, net	(0.4)	0.6
Net change in defined benefit plans arising during the period	(2)	(2.7)
Amortization of net actuarial (gains) losses included in compensation and benefits expense	1.2	1.2
Income tax benefit (expense)	0.2	0.4
Defined benefit plans, net	(0.6)	(1.1)
Net unrealized holding gains (losses) during the period	0	0.3
Reclassification of net unrealized (gains) losses to interest expense and other non-operating income (expense)	(1.8)	(0.3)
Income tax benefit (expense)	0.4	0
Derivative investments, net	(1.4)	0
Foreign currency translation adjustments	(27.8)	(4)
Reclassification of net (gains) losses from foreign currency entities to other expenses	0.6	0
Income tax benefit (expense)	0	0
Foreign currency translation, net	(27.2)	(4)
Other comprehensive income (loss), net of tax	(29.6)	(4.5)
Comprehensive Income	737.2	491.4
Comprehensive (Income) Loss Attributable to Noncontrolling Interest	(0.6)	1
Comprehensive Income attributable to CME Group	$ 736.6	$ 492.4

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock And Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Noncontrolling Interest [Member]	Class A Common Stock [Member]	Class A Common Stock [Member]Common Stock And Additional Paid-In Capital [Member]	Class B Common Stock [Member]	Class B Common Stock [Member]Common Stock And Additional Paid-In Capital [Member]
Balance (in shares) at Dec. 31, 2018								356,824		3
Balance at Dec. 31, 2018	$ 25,965.3	$ 21,057.9	$ 4,855.3	$ 5.3	$ 25,918.5
Balance at Dec. 31, 2018						$ 46.8
Net (Income) Loss Attributable to Noncontrolling Interest	1					1
Net Income (Loss) Attributable to CME Group	496.9		496.9		496.9
Net Income	495.9
Other comprehensive income (loss), net of tax	(4.5)			(4.5)	(4.5)
Dividends on common stock	(268)		(268)		(268)
Cumulative Effect on Retained Earnings, Net of Tax	(6.9)		6.9		6.9
Changes in non-controlling interest due to measurement period adjustments	(16.9)				0	(16.9)
Exercise of stock options, shares								64
Exercise of stock options	3.3	3.3			3.3
Vesting of issued restricted Class A common stock, shares								125
Vesting of issued restricted Class A common stock	(13.8)	(13.8)			(13.8)
Stock-based compensation	18.3	18.3			18.3
Balance (in shares) at Mar. 31, 2019								357,013		3
Balance at Mar. 31, 2019	26,186.5	21,065.7	5,091.1	0.8	26,157.6
Balance at Mar. 31, 2019						28.9
Balance (in shares) at Dec. 31, 2019							357,469	357,469	3	3
Balance at Dec. 31, 2019	26,128.9	21,116.8	5,008.7	3.4	26,128.9
Balance at Dec. 31, 2019						30.4
Balance at Dec. 31, 2019	26,159.3
Net (Income) Loss Attributable to Noncontrolling Interest	(0.6)					0.6
Net Income (Loss) Attributable to CME Group	766.2		766.2		766.2
Net Income	766.8
Other comprehensive income (loss), net of tax	(29.6)			(29.6)	(29.6)
Dividends on common stock	(304.7)		(304.7)		(304.7)
Cumulative Effect on Retained Earnings, Net of Tax	(0.3)		(0.3)		(0.3)
Exercise of stock options, shares								55
Exercise of stock options	3.2	3.2			3.2
Vesting of issued restricted Class A common stock, shares								153
Vesting of issued restricted Class A common stock	(19.1)	(19.1)			(19.1)
Stock-based compensation	23.1	23.1			23.1
Balance (in shares) at Mar. 31, 2020							357,677	357,677	3	3
Balance at Mar. 31, 2020	26,567.7	$ 21,124	$ 5,469.9	$ (26.2)	$ 26,567.7
Balance at Mar. 31, 2020						$ 31
Balance at Mar. 31, 2020	$ 26,598.7

Consolidated Statements Of Sh_2

Consolidated Statements Of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Stockholders' Equity [Abstract]
Cash dividends on common stock, per share (in dollars per share)	$ 0.85	$ 0.75

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flows from Operating Activities
Net Income	$ 766.8	$ 495.9
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	23.1	18.3
Amortization of purchased intangibles	77.3	80.7
Depreciation and amortization	35.3	32.9
Net losses on impaired assets	23.1	0
Net loss on derivative contracts	(1.5)	14.4
Net realized and unrealized (gains) losses on investments	(2.9)	3.4
Undistributed net earnings of unconsolidated subsidiaries	(0.2)	(22.6)
Deferred income taxes	(9.7)	(0.6)
Change in:
Accounts receivable	(309.5)	(5.5)
Other current assets	(14.5)	45.4
Other assets	18.8	(9.8)
Accounts payable	12.4	(50.6)
Income taxes payable	186.1	141.3
Other current liabilities	(22.1)	(73.1)
Other liabilities	(29.5)	0.3
Other	4.1	(1.2)
Net Cash Provided by (Used in) Operating Activities	757.1	669.2
Cash Flows from Investing Activities
Proceeds from maturities of available-for-sale marketable securities	2.2	6.1
Purchases of available-for-sale marketable securities	(2.4)	(5.6)
Purchases of property, net	(42.8)	(49.1)
Net Cash Used in Investing Activities	(43)	(48.6)
Cash Flows from Financing Activities
Issuance of commercial paper, net of maturities	(204.6)	462.3
Repayments of debt	0	(569.2)
Cash dividends	(1,197.6)	(892.1)
Settlement of derivative contracts	0	16
Employee taxes paid on restricted stock vesting	(19.1)	(13.8)
Other	7.4	(0.9)
Net Cash Used in Financing Activities	(1,413.9)	(997.7)
Net change in cash, cash equivalents and restricted cash	(699.8)	(377.1)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, beginning balance	1,556.6	1,377.2
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, ending balance	856.8	1,000.1
Cash and cash equivalents	851.7	997.4
Short-term restricted cash	4.3	1.6
Long-term restricted cash	0.8	1.1
Income taxes paid	39	0
Interest paid	$ 42.4	$ 55.4

Basis Of Presentation

Basis Of Presentation	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis Of Presentation	Basis of Presentation The consolidated financial statements consist of CME Group Inc. (CME Group) and its subsidiaries (collectively, the company), including Chicago Mercantile Exchange Inc. (CME), Board of Trade of the City of Chicago, Inc. (CBOT), New York Mercantile Exchange, Inc. (NYMEX), Commodity Exchange, Inc. (COMEX) and NEX Group Limited (NEX). The clearing house is a division of CME. The accompanying interim consolidated financial statements have been prepared by CME Group without audit. Certain notes and other information normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States have been condensed or omitted. In the opinion of management, the accompanying consolidated financial statements include all normal recurring adjustments considered necessary to present fairly the financial position of the company at March 31, 2020 and December 31, 2019 and the results of operations and cash flows for the periods indicated. Quarterly results are not necessarily indicative of results for any subsequent period. The accompanying consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto in CME Group’s Annual Report on Form 10-K for the year ended December 31, 2019 , filed with the Securities and Exchange Commission (SEC) on February 28, 2020.

Accounting Policies (Notes)

Accounting Policies (Notes)	3 Months Ended
	Mar. 31, 2020
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Changes [Text Block]	Accounting Policies Newly Adopted Accounting Policies. The company adopted the following accounting policies during 2020: Credit Losses. In June 2016, the FASB issued guidance that changes how credit losses are measured for most financial assets measured at amortized cost and certain other instruments. The standard requires an entity to estimate its lifetime expected credit loss and record an allowance, that when deducted from the amortized cost basis of the financial asset, presents the net amount expected to be collected on the financial asset. This forward-looking expected loss model generally will result in the earlier recognition of allowances for losses. The standard also amends the impairment model for available for sale debt securities and requires entities to determine whether all or a portion of the unrealized loss on an available for sale debt security is a credit loss. Severity and duration of the unrealized loss are no longer permissible factors in concluding whether a credit loss exists. Entities will recognize improvements to estimated credit losses on available for sale debt securities immediately in earnings rather than as interest income over time. The company implemented this standard on January 1, 2020 by recognizing an immaterial cumulative-effect adjustment to the beginning balance of retained earnings. The company has not experienced significant levels of underpayment or nonpayment by customers and does not expect changes to this trend over the payment terms of our receivables. Exposure to losses on receivables for clearing and transaction fees and other amounts owed by clearing and trading firms is dependent on each firm's financial condition. With respect to clearing firms, the company's credit loss exposure is mitigated by the memberships that collateralize fees owed to the company. The allowance for credit losses on accounts receivable is calculated by evaluating the aging of the company's billings by revenue stream: clearing and transaction, market data, and other. This aging assessment, as well as contemplation of current and anticipated economic factors, including the interest rate environment and pricing levels are the primary considerations that most significantly impact the collectibility of accounts receivable. The allowance for accounts receivable is $4.8 million at March 31, 2020. Income Taxes. In December 2019, the FASB issued an accounting update that is intended to reduce cost and complexity related to accounting for income taxes. The update removes specific exceptions to the general principles for accounting for income taxes. Specifically, it eliminates the need for an entity to analyze whether the following exceptions apply in a given period: incremental approach for intraperiod tax allocation, accounting basis differences when there are ownership changes in foreign investments, and interim period income tax accounting for year-to-date losses that exceed anticipated losses. The update also simplifies the accounting for the following: franchise taxes that are partially based on income, transactions with a government that result in a step up in the tax basis of goodwill, separate financial statements of legal entities that are not subject to tax, and enacted changes in tax laws in interim periods. This update is effective for reporting periods beginning after December 15, 2020. The company has early adopted this standard on January 1, 2020. The impact of adoption of this standard was immaterial to the consolidated financial statements. Recently Issued Accounting Pronouncements. In August 2018, the FASB issued a standards update that modifies the disclosure requirements for employers that sponsor defined pension or other postretirement plans. The guidance clarifies certain existing disclosures and expands the requirements for others. Disclosures that are not considered cost beneficial are removed by the update. Also, there is a new disclosure requirement to include an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. This guidance is effective for reporting periods beginning in 2021. Early adoption is permitted. The company plans to update the disclosures for these changes upon adoption of the guidance in 2021.

Revenue Recognition (Notes)

Revenue Recognition (Notes)	3 Months Ended
	Mar. 31, 2020
Revenue Recognition [Abstract]
Revenue Recognition, Deferred Revenue [Policy Text Block]	Revenue Recognition The company generates revenue from customers from the following sources: Clearing and transaction fees. Clearing and transaction fees include electronic trading fees and brokerage commissions, surcharges for privately-negotiated transactions, portfolio reconciliation and compression services, risk mitigation and other volume-related charges for trade contracts. Clearing and transaction fees are assessed upfront at the time of trade execution. As such, the company recognizes the majority of the fee revenue upon successful execution of the trade. The minimal remaining portion of the fee revenue related to settlement activities performed after trade execution is recognized over the short-term period that the contract is outstanding, based on management’s estimates of the average contract lifecycle. These estimates are based on various assumptions to approximate the amount of fee revenue to be attributed to services performed through contract settlement, expiration, or termination. For cleared trades, these assumptions include the average number of days that a contract remains in open interest, contract turnover, average revenue per day, and revenue remaining in open interest at the end of each period. The nature of contracts gives rise to several types of variable consideration, including volume-based pricing tiers, customer incentives associated with market maker programs and other fee discounts. The company includes fee discounts and incentives in the estimated transaction price when there is a basis to reasonably estimate the amount of the fee reduction. These estimates are based on historical experience, anticipated performance, and best judgment at the time. Because of the company's certainty in estimating these amounts, they are included in the transaction price of contracts. Market data and information services. Market data and information services represent revenue from the dissemination of market data to subscribers, distributors, and other third-party licensees of market data. Pricing for market data is primarily based on the number of reportable devices used as well as the number of subscribers enrolled under the arrangement. Fees for these services are generally billed monthly. Market data services are satisfied over time and revenue is recognized on a monthly basis as the customers receive and consume the benefit of the market data services. However, the company also maintains certain annual license arrangements with one-time upfront fees. The fees for annual licenses are initially recorded as a contract liability and recognized as revenue monthly over the term of the annual period. Other. Other revenues include certain access and communication fees, fees for collateral management and fees for trade order routing through agreements from various strategic relationships. Access and communication fees are charges to customers that utilize various telecommunications networks and communications services. Fees for these services are generally billed monthly and the associated fee revenue is recognized as billed. Collateral management fees are charged to clearing firms that have collateral on deposit with the clearing house to meet their minimum performance bond and guaranty fund obligations on the exchange. These fees are calculated based on daily collateral balances and are billed monthly. This fee revenue is recognized monthly as billed as the customers receive and consume the benefits of the services. Pricing for strategic relationships may be driven by customer levels and activity. There are fee arrangements which provide for monthly as well as quarterly payments in arrears. Revenue is recognized monthly for strategic relationship arrangements as the customers receive and consume the benefits of the services. The following table represents a disaggregation of revenue from contracts with customers for the quarters ended March 31, 2020 and 2019 : Quarter Ended (in millions) 2020 2019 Interest rates $ 418.3 $ 302.8 Equity indexes 248.2 145.9 Foreign exchange 48.2 41.2 Agricultural commodities 117.7 105.0 Energy 221.8 165.0 Metals 78.8 51.0 Cash markets business 124.4 122.9 Interest rate swap 21.4 18.8 Total clearing and transaction fees 1,278.8 952.6 Market data and information services 131.5 130.1 Other 111.8 96.9 Total revenues $ 1,522.1 $ 1,179.6 Timing of Revenue Recognition Services transferred at a point in time $ 1,211.2 $ 892.9 Services transferred over time 307.5 277.7 One-time charges and miscellaneous revenues 3.4 9.0 Total revenues $ 1,522.1 $ 1,179.6 The timing of revenue recognition, billings and cash collections results in billed accounts receivable, and customer advances and deposits (contract liabilities) on the consolidated balance sheets. Certain fees for transactions, annual licenses, and other revenue arrangements are billed upfront before revenue is recognized, which results in the recognition of contract liabilities. These liabilities are recognized on the consolidated balance sheets on a contract-by-contract basis at the end of each reporting period. For annual licenses and upfront fee arrangements, the company generally bills customers upon contract execution. These payments are recognized as revenue over time as the obligations under the contracts are satisfied. Changes in the contract liability balances during the quarter ended March 31, 2020 were not materially impacted by any other factors. The balance of contract liabilities was $61.8 million and $42.6 million as of March 31, 2020 and December 31, 2019

Performance Bonds and Guaranty

Performance Bonds and Guaranty Fund Contributions (Notes)	3 Months Ended
	Mar. 31, 2020
Performance Bonds and Guaranty Fund Contributions [Abstract]
Performance Bonds and Guaranty Fund Contributions	Performance Bonds and Guaranty Fund Contributions Performance Bonds and Guaranty Fund Contributions. At March 31, 2020 , performance bonds and guaranty fund contribution assets on the consolidated balance sheets include cash as well as U.S. Treasury securities and U.S. government agency securities. U.S. Treasury securities and U.S. government agency securities are purchased by CME, at its discretion, using cash collateral. The benefits, including interest earned, and risks of ownership accrue to CME. Interest earned is included in investment income on the consolidated statements of income. These debt securities are classified as available-for-sale. At March 31, 2020 , the amortized cost and fair value of the U.S. Treasury securities were both $1.4 billion . At March 31, 2020 , the amortized cost and fair value of the U.S. government agency securities were both $1.8 billion . CME has been designated as a systemically important financial market utility by the Financial Stability Oversight Council and is authorized to establish and maintain a cash account at the Federal Reserve Bank of Chicago. At March 31, 2020 , CME maintained $84.9 billion within the cash account at the Federal Reserve Bank of Chicago. The cash deposit at the Federal Reserve Bank of Chicago is included within performance bonds and guaranty fund contributions on the consolidated balance sheets. Clearing House Contract Settlement. The clearing house marks-to-market open positions for all futures and options contracts twice a day (once a day for CME's cleared-only interest rate swap contracts). Based on values derived from the mark-to-market process, the clearing house requires payments from clearing firms whose positions have lost value and makes payments to clearing firms whose positions have gained value. Under the extremely unlikely scenario of simultaneous default by every clearing firm who has open positions with unrealized losses, the maximum exposure related to positions other than cleared-only interest rate swap contracts would be one half day of changes in fair value of all open positions, before considering the clearing house's ability to access defaulting clearing firms' collateral deposits. For CME's cleared-only interest rate swap contracts, the maximum exposure related to CME's guarantee would be one full day of changes in fair value of all open positions, before considering CME's ability to access defaulting clearing firms' collateral. During the first quarter of 2020, the clearing house transferred an average of approximately $6.8 billion a day through its clearing systems for settlement from clearing firms whose positions had lost value to clearing firms whose positions had gained value. The clearing house reduces its guarantee exposure through initial and maintenance performance bond requirements and mandatory guaranty fund contributions. The company believes that its guarantee liability is immaterial and therefore has not recorded any liability at March 31, 2020

Intangible Assets And Goodwill

Intangible Assets And Goodwill	3 Months Ended
	Mar. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets And Goodwill	Intangible Assets Intangible assets consisted of the following at March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 (in millions) Assigned Value Accumulated Amortization Net Book Value Assigned Value Accumulated Amortization Net Book Value Amortizable Intangible Assets: Clearing firm, market data and other customer relationships $ 5,756.6 $ (1,411.4 ) $ 4,345.2 $ 5,797.1 $ (1,346.0 ) $ 4,451.1 Technology-related intellectual property 170.1 (51.0 ) 119.1 174.3 (46.6 ) 127.7 Other 100.9 (17.3 ) 83.6 103.8 (14.9 ) 88.9 Total amortizable intangible assets $ 6,027.6 $ (1,479.7 ) 4,547.9 $ 6,075.2 $ (1,407.5 ) 4,667.7 Indefinite-Lived Intangible Assets: Trade names 450.0 450.0 Total intangible assets – other, net $ 4,997.9 $ 5,117.7 Trading products (1) $ 17,175.3 $ 17,175.3 (1) Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the Commodity Futures Trading Commission (CFTC). Product authorizations from the CFTC have no term limits. Total amortization expense for intangible assets was $77.3 million and $80.7 million for the quarters ended March 31, 2020 and 2019 , respectively. As of March 31, 2020 , the future estimated amortization expense related to amortizable intangible assets is expected to be as follows: (in millions) Amortization Expense Remainder of 2020 $ 231.7 2021 308.9 2022 308.5 2023 307.2 2024 300.5 2025 300.3 Thereafter 2,790.8

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt Long-term debt consisted of the following at March 31, 2020 and December 31, 2019 : (in millions) March 31, 2020 December 31, 2019 $750.0 million fixed rate notes due September 2022, stated rate of 3.00% (1) $ 747.9 $ 747.7 €15.0 million fixed rate notes due May 2023, stated rate of 4.30% 16.2 16.4 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (2) 746.5 746.3 $500.0 million fixed rate notes due June 2028, stated rate of 3.75% 496.5 496.4 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (3) 742.8 742.8 $700.0 million fixed rate notes due June 2048, stated rate of 4.15% 689.9 689.8 Commercial paper (4) 100.0 303.8 Total long-term debt $ 3,539.8 $ 3,743.2 (1) The company maintained a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 3.32% . (2) The company maintained a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 3.11% . (3) The company maintained a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 4.73% . (4) The commercial paper is backed by the five-year multi-currency revolving credit facility. Commercial paper with an aggregate par value of $1.1 billion and maturities ranging from 1 to 18 days was issued during the first quarter of 2020. The weighted average discount rate of commercial paper outstanding at March 31, 2020 was 1.68% . The weighted average balance of commercial paper outstanding during the first quarter of 2020 was $178.0 million . Long-term debt maturities, at par value (in U.S. dollar equivalent), were as follows at March 31, 2020 : (in millions) Par Value 2021 $ — 2022 850.0 2023 16.6 2024 — 2025 750.0 Thereafter 1,950.0 Commercial paper is considered to mature in 2022 because it is backed by the five-year multi-currency revolving credit facility, which expires in 2022.

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2020
Loss Contingency [Abstract]
Contingencies	Contingencies Legal and Regulatory Matters. In 2013, the CFTC filed suit against NYMEX and two former employees alleging disclosure of confidential customer information in violation of the Commodity Exchange Act. The case is set for trial in October 2020. Based on its investigation to date and advice from legal counsel, the company believes that it has strong factual and legal defenses to the claim. In 2003, the U.S. Futures Exchange, L.L.C. (Eurex U.S.) and U.S. Exchange Holdings, Inc. filed suit in federal court alleging that CBOT and CME violated the antitrust laws and tortuously interfered with the business relationship and contract between Eurex U.S. and The Clearing Corporation. On October 31, 2018, the district court granted CBOT's and CME's motion for summary judgment and dismissed the case in its entirety. On March 23, 2020, the Seventh Circuit affirmed the decision of the district court. In the normal course of business, the company discusses matters with its regulators raised during regulatory examinations or otherwise subject to their inquiry and oversight. These matters could result in censures, fines, penalties or other sanctions. Management believes the outcome of any resulting actions will not have a material impact on its consolidated financial position or results of operations. However, the company is unable to predict the outcome or the timing of the ultimate resolution of these matters, or the potential fines, penalties or injunctive or other equitable relief, if any, that may result from these matters. In addition, the company is a defendant in, and has potential for, various other legal proceedings arising from its regular business activities. While the ultimate results of such proceedings against the company cannot be predicted with certainty, the company believes that the resolution of any of these matters on an individual or aggregate basis will not have a material impact on its consolidated financial position or results of operations. No accrual was required for legal and regulatory matters as none were probable and estimable as of March 31, 2020 and December 31, 2019 . Intellectual Property Indemnifications . Certain agreements with customers and other third parties related to accessing the CME Group platforms, utilizing market data services and licensing CME SPAN software may contain indemnifications from intellectual property claims that may be made against them as a result of their use of the applicable products and/or services. The potential future claims relating to these indemnifications cannot be estimated and therefore no liability has been recorded.

Leases (Notes)

Leases (Notes)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Lessee, Leases [Policy Text Block]	Leases The company has operating leases for datacenters, corporate offices, and certain information technology equipment. The operating leases have remaining lease terms of up to 18 years, some of which include options to extend or renew the leases for up to an additional five years, and some of which include options to early terminate the leases in less than 12 months. Management evaluates the exercisability of these options at least quarterly in order to determine whether the contract term must be reassessed. For a small number of the leases, primarily the international locations, management's approach is to enter into short-term leases for a lease term of 12 months or less in order to provide for greater flexibility in the local environment. For certain office spaces, the company has entered into arrangements to sublease excess space to third parties, while the original lease contract remains in effect with the landlord. The company also has one finance lease, which is related to the sale of our datacenter in March 2016. In connection with the sale, the company leased back a portion of the property. The sale leaseback transaction was recognized under the financing method and not as a sale leaseback arrangement. The right-of-use lease asset is recorded within other assets, and the present value of the lease liability is recorded within other liabilities (segregated between short term and long term) on the consolidated balance sheets. The discount rate applied to the lease payments represents the company's incremental borrowing rate. The components of lease costs were as follows: Quarter Ended (in millions) 2020 2019 Operating lease expense: Operating lease cost $ 14.9 $ 18.4 Short-term lease cost 0.2 3.4 Total operating lease expense included in other expense $ 15.1 $ 21.8 Finance lease expense: Interest expense $ 0.9 $ 0.9 Depreciation expense 2.2 2.2 Total finance lease expense $ 3.1 $ 3.1 Sublease revenue included in other revenue $ 3.6 $ 3.3 Supplemental cash flow information related to leases was as follows: Quarter Ended (in millions) 2020 2019 Cash outflows for operating leases $ 15.9 $ 15.2 Cash outflows for finance leases 4.2 4.2 Supplemental balance sheet information related to leases was as follows: Operating leases (in millions) March 31, 2020 December 31, 2019 Operating lease right-of-use assets $ 406.7 $ 417.1 Operating lease liabilities: Other current liabilities $ 41.6 $ 42.3 Other liabilities 496.3 514.8 Total operating lease liabilities $ 537.9 $ 557.1 Weighted average remaining lease term (in months) 145 146 Weighted average discount rate 4.0 % 4.0 % Finance leases (in millions) March 31, 2020 December 31, 2019 Finance lease right-of-use assets $ 95.3 $ 97.5 Finance lease liabilities: Other current liabilities $ 7.5 $ 7.4 Other liabilities 89.6 91.5 Total finance lease liabilities $ 97.1 $ 98.9 Weighted average remaining lease term (in months) 132 135 Weighted average discount rate 3.5 % 3.5 % Future minimum lease payments were as follows as of March 31, 2020 for operating and finance leases: (in millions) Operating Leases Remainder of 2020 $ 47.9 2021 61.2 2022 64.2 2023 60.5 2024 55.1 2025 53.5 Thereafter 345.3 Total lease payments 687.7 Less: imputed interest (149.8 ) Present value of lease liability $ 537.9 (in millions) Finance Leases Remainder of 2020 $ 12.7 2021 17.0 2022 17.1 2023 17.2 2024 17.4 2025 17.5 Thereafter 94.3 Total lease payments 193.2 Less: imputed interest (96.1 ) Present value of lease liability $ 97.1

Guarantees

Guarantees	3 Months Ended
	Mar. 31, 2020
Guarantees [Abstract]
Guarantees	Guarantees Mutual Offset Agreement. CME and Singapore Exchange Limited (SGX) maintain a mutual offset agreement with a current term through October 2020. This agreement enables market participants to open a futures position on one exchange and liquidate it on the other. The term of the agreement will automatically renew for a one -year period unless either party provides advance notice of their intent to terminate. CME can maintain collateral in the form of U.S. Treasury securities or irrevocable, standby letters of credit. At March 31, 2020 , CME was contingently liable to SGX on letters of credit totaling $310.0 million . Regardless of the collateral, CME guarantees all cleared transactions submitted through SGX and would initiate procedures designed to satisfy these financial obligations in the event of a default, such as the use of performance bonds and guaranty fund contributions of the defaulting clearing firm. The company believes that its guarantee liability is immaterial and therefore has not recorded any liability at March 31, 2020 . Family Farmer and Rancher Protection Fund. In 2012, the company established the Family Farmer and Rancher Protection Fund (the Fund). The Fund is designed to provide payments, up to certain maximum levels, to family farmers, ranchers and other agricultural industry participants who use the company's agricultural commodity products and who suffer losses to their segregated account balances due to their CME clearing member becoming insolvent. Under the terms of the Fund, farmers and ranchers are eligible for up to $25,000 per participant. Farming and ranching cooperatives are eligible for up to $100,000 per cooperative. The Fund was established with a maximum of $100.0 million available for distribution to participants. Since its establishment, the Fund has made payments of approximately $2.0 million , which leaves $98.0 million available for future claims. If, at any time, payments due to participants were to exceed the amount remaining in the fund, payments would be pro-rated. Clearing members and customers must register with the company in advance and provide certain documentation in order to substantiate their eligibility. The company believes that its guarantee liability is immaterial and therefore has not recorded any liability at March 31, 2020

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Notes)	3 Months Ended
	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The following tables present changes in the accumulated balances for each component of other comprehensive income (loss), including current period other comprehensive income (loss) and reclassifications out of accumulated other comprehensive income (loss): (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2019 $ 0.8 $ (55.1 ) $ 69.0 $ (11.3 ) $ 3.4 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) (0.6 ) (2.0 ) — (27.8 ) (30.4 ) Amounts reclassified from accumulated other comprehensive income (loss) — 1.2 (1.8 ) 0.6 — Income tax benefit (expense) 0.2 0.2 0.4 — 0.8 Net current period other comprehensive income (loss) (0.4 ) (0.6 ) (1.4 ) (27.2 ) (29.6 ) Balance at March 31, 2020 $ 0.4 $ (55.7 ) $ 67.6 $ (38.5 ) $ (26.2 ) (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2018 $ 0.1 $ (53.8 ) $ 69.7 $ (10.7 ) $ 5.3 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) 0.8 (2.7 ) 0.3 (4.0 ) (5.6 ) Amounts reclassified from accumulated other comprehensive income (loss) — 1.2 (0.3 ) — 0.9 Income tax benefit (expense) (0.2 ) 0.4 — — 0.2 Net current period other comprehensive income (loss) 0.6 (1.1 ) — (4.0 ) (4.5 ) Balance at March 31, 2019 $ 0.7 $ (54.9 ) $ 69.7 $ (14.7 ) $ 0.8

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value by Fair Value Hierarchy Level Extensible List [Abstract]
Fair Value Measurements	Fair Value Measurements The company uses a three-level classification hierarchy of fair value measurements for disclosure purposes: • Level 1 inputs, which are considered the most reliable evidence of fair value, consist of quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2 inputs consist of observable market data, such as quoted prices for similar assets and liabilities in active markets, or inputs other than quoted prices that are directly observable. • Level 3 inputs consist of unobservable inputs which are derived and cannot be corroborated by market data or other entity-specific inputs. Level 1 assets generally include investments in publicly traded mutual funds, equity securities, corporate debt securities and U.S. government securities with quoted market prices. In general, the company uses quoted prices in active markets for identical assets to determine the fair value of marketable securities. Level 2 assets and liabilities generally consist of asset-backed securities and long-term debt notes. Asset-backed securities were measured at fair value based on matrix pricing using prices of similar securities with similar inputs such as maturity dates, interest rates and credit ratings. The fair values of the long-term debt notes were based on quoted market prices in an inactive market. Level 3 assets include certain fixed assets, intangible assets and investments that were impaired or written up in fair value. Recurring Fair Value Measurements. Financial assets and liabilities recorded at fair value on the consolidated balance sheet as of March 31, 2020 were classified in their entirety based on the lowest level of input that was significant to each asset and liability's fair value measurement. The following table presents financial instruments measured at fair value on a recurring basis: March 31, 2020 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 17.3 $ — $ — $ 17.3 Mutual funds 59.9 — — 59.9 Equity securities 0.1 — — 0.1 Asset-backed securities — 0.2 — 0.2 Total Marketable Securities 77.3 0.2 — 77.5 Performance bonds and guaranty fund contributions (1) : U.S. Treasury securities 1,369.9 — — 1,369.9 U.S. government agency securities 1,838.4 — — 1,838.4 Total Assets at Fair Value $ 3,285.6 $ 0.2 $ — $ 3,285.8 (1) Performance bonds and guaranty fund contributions on the consolidated balance sheet at March 31, 2020 include U.S. Treasury securities and U.S. government agency securities purchased with cash collateral. Non-Recurring Fair Value Measurements. During the first quarter of 2020, the company recognized impairment charges of $23.1 million related to certain intangible assets and fixed assets of a subsidiary. The combined fair values of net assets were estimated to be zero at March 31, 2020. The company also recognized unrealized gains on certain investments of $2.9 million . The combined fair value of these investments were estimated to be $18.3 million at March 31, 2020. These assessments were based on quantitative and qualitative indications of impairment. The fair value measurements of the intangible assets, fixed assets and investments are considered level 3 and non-recurring. Fair Values of Long-Term Debt Notes. The following presents the estimated fair values of long-term debt notes, which are carried at amortized cost on the consolidated balance sheets. The fair values below that are classified as level 2 under the fair value hierarchy were estimated using quoted market prices in inactive markets. The fair value of the debt facility that was classified as level 3 under the fair value hierarchy was estimated based on assumptions made by management regarding expectations of future settlement of the debt. At March 31, 2020 , the fair values (in U.S. dollar equivalent) were as follows: (in millions) Fair Value Level $750.0 million fixed rate notes due September 2022 $ 760.7 Level 2 €15.0 million fixed rate notes due May 2023 17.6 Level 2 $750.0 million fixed rate notes due March 2025 774.7 Level 2 $500.0 million fixed rate notes due June 2028 560.2 Level 2 $750.0 million fixed rate notes due September 2043 1,095.1 Level 2 $700.0 million fixed rate notes due June 2048 918.0 Level 2 Commercial paper 100.0 Level 3

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share is computed by dividing net income by the weighted average number of shares of all classes of CME Group common stock outstanding for each reporting period. Diluted earnings per share reflects the increase in shares using the treasury stock method to reflect the impact of an equivalent number of shares of common stock if stock options were exercised and restricted stock awards were converted into common stock. Anti-dilutive stock awards were as follows for the periods presented: Quarter Ended (in thousands) 2020 2019 Stock awards 68 76 Total 68 76 The following table presents the earnings per share calculation for the periods presented: Quarter Ended 2020 2019 Net Income Attributable to CME Group (in millions) $ 766.2 $ 496.9 Weighted Average Number of Common Shares (in thousands): Basic 357,524 356,886 Effect of stock options, restricted stock and performance shares 931 1,161 Diluted 358,455 358,047 Earnings per Common Share Attributable to CME Group: Basic $ 2.14 $ 1.39 Diluted 2.14 1.39

Subsequent Events (Notes)

Subsequent Events (Notes)	3 Months Ended
	Mar. 31, 2020
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent EventsThe company has evaluated subsequent events through the date the financial statements were issued. The company has determined that there were no subsequent events.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2020
Revenue Recognition [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table represents a disaggregation of revenue from contracts with customers for the quarters ended March 31, 2020 and 2019 : Quarter Ended (in millions) 2020 2019 Interest rates $ 418.3 $ 302.8 Equity indexes 248.2 145.9 Foreign exchange 48.2 41.2 Agricultural commodities 117.7 105.0 Energy 221.8 165.0 Metals 78.8 51.0 Cash markets business 124.4 122.9 Interest rate swap 21.4 18.8 Total clearing and transaction fees 1,278.8 952.6 Market data and information services 131.5 130.1 Other 111.8 96.9 Total revenues $ 1,522.1 $ 1,179.6 Timing of Revenue Recognition Services transferred at a point in time $ 1,211.2 $ 892.9 Services transferred over time 307.5 277.7 One-time charges and miscellaneous revenues 3.4 9.0 Total revenues $ 1,522.1 $ 1,179.6

Intangible Assets And Goodwill

Intangible Assets And Goodwill (Tables)	3 Months Ended
	Mar. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Components of intangible assets	Intangible assets consisted of the following at March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 (in millions) Assigned Value Accumulated Amortization Net Book Value Assigned Value Accumulated Amortization Net Book Value Amortizable Intangible Assets: Clearing firm, market data and other customer relationships $ 5,756.6 $ (1,411.4 ) $ 4,345.2 $ 5,797.1 $ (1,346.0 ) $ 4,451.1 Technology-related intellectual property 170.1 (51.0 ) 119.1 174.3 (46.6 ) 127.7 Other 100.9 (17.3 ) 83.6 103.8 (14.9 ) 88.9 Total amortizable intangible assets $ 6,027.6 $ (1,479.7 ) 4,547.9 $ 6,075.2 $ (1,407.5 ) 4,667.7 Indefinite-Lived Intangible Assets: Trade names 450.0 450.0 Total intangible assets – other, net $ 4,997.9 $ 5,117.7 Trading products (1) $ 17,175.3 $ 17,175.3 (1) Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the Commodity Futures Trading Commission (CFTC). Product authorizations from the CFTC have no term limits.
Future estimated amortization expense	As of March 31, 2020 , the future estimated amortization expense related to amortizable intangible assets is expected to be as follows: (in millions) Amortization Expense Remainder of 2020 $ 231.7 2021 308.9 2022 308.5 2023 307.2 2024 300.5 2025 300.3 Thereafter 2,790.8

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	Long-term debt consisted of the following at March 31, 2020 and December 31, 2019 : (in millions) March 31, 2020 December 31, 2019 $750.0 million fixed rate notes due September 2022, stated rate of 3.00% (1) $ 747.9 $ 747.7 €15.0 million fixed rate notes due May 2023, stated rate of 4.30% 16.2 16.4 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (2) 746.5 746.3 $500.0 million fixed rate notes due June 2028, stated rate of 3.75% 496.5 496.4 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (3) 742.8 742.8 $700.0 million fixed rate notes due June 2048, stated rate of 4.15% 689.9 689.8 Commercial paper (4) 100.0 303.8 Total long-term debt $ 3,539.8 $ 3,743.2 (1) The company maintained a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 3.32% . (2) The company maintained a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 3.11% . (3) The company maintained a forward-starting interest rate swap agreement that modified the interest obligation associated with these notes so that the interest payable on the notes effectively became fixed at a rate of 4.73% . (4) The commercial paper is backed by the five-year multi-currency revolving credit facility.
Schedule of Maturities of Long-term Debt [Table Text Block]	Long-term debt maturities, at par value (in U.S. dollar equivalent), were as follows at March 31, 2020 : (in millions) Par Value 2021 $ — 2022 850.0 2023 16.6 2024 — 2025 750.0 Thereafter 1,950.0

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Lease, Cost [Table Text Block]	The components of lease costs were as follows: Quarter Ended (in millions) 2020 2019 Operating lease expense: Operating lease cost $ 14.9 $ 18.4 Short-term lease cost 0.2 3.4 Total operating lease expense included in other expense $ 15.1 $ 21.8 Finance lease expense: Interest expense $ 0.9 $ 0.9 Depreciation expense 2.2 2.2 Total finance lease expense $ 3.1 $ 3.1 Sublease revenue included in other revenue $ 3.6 $ 3.3
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Supplemental cash flow information related to leases was as follows: Quarter Ended (in millions) 2020 2019 Cash outflows for operating leases $ 15.9 $ 15.2 Cash outflows for finance leases 4.2 4.2
Schedule of Amounts Recognized in Balance Sheet [Table Text Block]	Supplemental balance sheet information related to leases was as follows: Operating leases (in millions) March 31, 2020 December 31, 2019 Operating lease right-of-use assets $ 406.7 $ 417.1 Operating lease liabilities: Other current liabilities $ 41.6 $ 42.3 Other liabilities 496.3 514.8 Total operating lease liabilities $ 537.9 $ 557.1 Weighted average remaining lease term (in months) 145 146 Weighted average discount rate 4.0 % 4.0 % Finance leases (in millions) March 31, 2020 December 31, 2019 Finance lease right-of-use assets $ 95.3 $ 97.5 Finance lease liabilities: Other current liabilities $ 7.5 $ 7.4 Other liabilities 89.6 91.5 Total finance lease liabilities $ 97.1 $ 98.9 Weighted average remaining lease term (in months) 132 135 Weighted average discount rate 3.5 % 3.5 %
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future minimum lease payments were as follows as of March 31, 2020 for operating and finance leases: (in millions) Operating Leases Remainder of 2020 $ 47.9 2021 61.2 2022 64.2 2023 60.5 2024 55.1 2025 53.5 Thereafter 345.3 Total lease payments 687.7 Less: imputed interest (149.8 ) Present value of lease liability $ 537.9
Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]	(in millions) Finance Leases Remainder of 2020 $ 12.7 2021 17.0 2022 17.1 2023 17.2 2024 17.4 2025 17.5 Thereafter 94.3 Total lease payments 193.2 Less: imputed interest (96.1 ) Present value of lease liability $ 97.1

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables present changes in the accumulated balances for each component of other comprehensive income (loss), including current period other comprehensive income (loss) and reclassifications out of accumulated other comprehensive income (loss): (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2019 $ 0.8 $ (55.1 ) $ 69.0 $ (11.3 ) $ 3.4 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) (0.6 ) (2.0 ) — (27.8 ) (30.4 ) Amounts reclassified from accumulated other comprehensive income (loss) — 1.2 (1.8 ) 0.6 — Income tax benefit (expense) 0.2 0.2 0.4 — 0.8 Net current period other comprehensive income (loss) (0.4 ) (0.6 ) (1.4 ) (27.2 ) (29.6 ) Balance at March 31, 2020 $ 0.4 $ (55.7 ) $ 67.6 $ (38.5 ) $ (26.2 ) (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2018 $ 0.1 $ (53.8 ) $ 69.7 $ (10.7 ) $ 5.3 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) 0.8 (2.7 ) 0.3 (4.0 ) (5.6 ) Amounts reclassified from accumulated other comprehensive income (loss) — 1.2 (0.3 ) — 0.9 Income tax benefit (expense) (0.2 ) 0.4 — — 0.2 Net current period other comprehensive income (loss) 0.6 (1.1 ) — (4.0 ) (4.5 ) Balance at March 31, 2019 $ 0.7 $ (54.9 ) $ 69.7 $ (14.7 ) $ 0.8

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments measured at fair value on a recurring basis	The following table presents financial instruments measured at fair value on a recurring basis: March 31, 2020 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 17.3 $ — $ — $ 17.3 Mutual funds 59.9 — — 59.9 Equity securities 0.1 — — 0.1 Asset-backed securities — 0.2 — 0.2 Total Marketable Securities 77.3 0.2 — 77.5 Performance bonds and guaranty fund contributions (1) : U.S. Treasury securities 1,369.9 — — 1,369.9 U.S. government agency securities 1,838.4 — — 1,838.4 Total Assets at Fair Value $ 3,285.6 $ 0.2 $ — $ 3,285.8 (1) Performance bonds and guaranty fund contributions on the consolidated balance sheet at March 31, 2020 include U.S. Treasury securities and U.S. government agency securities purchased with cash collateral.
Fair value of Debt Instruments	At March 31, 2020 , the fair values (in U.S. dollar equivalent) were as follows: (in millions) Fair Value Level $750.0 million fixed rate notes due September 2022 $ 760.7 Level 2 €15.0 million fixed rate notes due May 2023 17.6 Level 2 $750.0 million fixed rate notes due March 2025 774.7 Level 2 $500.0 million fixed rate notes due June 2028 560.2 Level 2 $750.0 million fixed rate notes due September 2043 1,095.1 Level 2 $700.0 million fixed rate notes due June 2048 918.0 Level 2 Commercial paper 100.0 Level 3

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Anti-dilutive stock awards were as follows for the periods presented: Quarter Ended (in thousands) 2020 2019 Stock awards 68 76 Total 68 76
Basic And Diluted Earnings Per Share	The following table presents the earnings per share calculation for the periods presented: Quarter Ended 2020 2019 Net Income Attributable to CME Group (in millions) $ 766.2 $ 496.9 Weighted Average Number of Common Shares (in thousands): Basic 357,524 356,886 Effect of stock options, restricted stock and performance shares 931 1,161 Diluted 358,455 358,047 Earnings per Common Share Attributable to CME Group: Basic $ 2.14 $ 1.39 Diluted 2.14 1.39

Accounting Policies (Details)

Accounting Policies (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounts receivable, allowance	$ 4.8	$ 3.4

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Revenue Recognition [Abstract]
Deferred Revenue	$ 61.8	$ 42.6

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Total Revenues	$ 1,522.1	$ 1,179.6
Services transferred at a point in time [Member]
Revenues	1,211.2	892.9
Services transferred over time [Member]
Revenues	307.5	277.7
One-time charges and miscellaneous revenues [Member]
Revenues	3.4	9
Clearing and transaction fees [Member]
Revenues	1,278.8	952.6
Clearing and transaction fees [Member] | Interest rate [Member]
Revenues	418.3	302.8
Clearing and transaction fees [Member] | Equities [Member]
Revenues	248.2	145.9
Clearing and transaction fees [Member] | Foreign Exchange [Member]
Revenues	48.2	41.2
Clearing and transaction fees [Member] | Agricultural commodity [Member]
Revenues	117.7	105
Clearing and transaction fees [Member] | Energy [Member]
Revenues	221.8	165
Clearing and transaction fees [Member] | Metal [Member]
Revenues	78.8	51
Clearing and transaction fees [Member] | Cash Markets [Member]
Revenues	124.4	122.9
Clearing and transaction fees [Member] | Interest Rate Swap [Member]
Revenues	21.4	18.8
Market data and information services
Revenues	131.5	130.1
Other
Revenues	$ 111.8	$ 96.9

Performance Bonds and Guarant_2

Performance Bonds and Guaranty Fund Contributions (Details) $ in Billions	3 Months Ended
	Mar. 31, 2020USD ($)
Guarantor Obligations [Line Items]
Average Daily Clearing Settlement	$ 6.8
Federal Reserve Reinvestment [Member]
Guarantor Obligations [Line Items]
Cash Equivalents, at Carrying Value	84.9
U.S. Treasury Performance Bond [Member]
Guarantor Obligations [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1.4
Available-for-sale Securities at Fair Value	1.4
U.S. Government Agency Security Performance Bond [Member]
Guarantor Obligations [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1.8
Available-for-sale Securities at Fair Value	$ 1.8

Intangible Assets And Goodwil_2

Intangible Assets And Goodwill (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of purchased intangibles	$ 77.3	$ 80.7

Intangible Assets And Goodwil_3

Intangible Assets And Goodwill (Components Of Intangible Assets) (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Intangible Assets [Line Items]
Intangible assets—Other, net		$ 4,997.9	$ 5,117.7
Intangible assets, trading products	[1]	17,175.3	17,175.3
Trade Names [Member]
Intangible Assets [Line Items]
Total intangible assets - other, net		450	450
Clearing Firm, Market Data And Other Customer Relationships [Member]
Intangible Assets [Line Items]
Assigned Value		5,756.6	5,797.1
Accumulated amortization		(1,411.4)	(1,346)
Net book value		4,345.2	4,451.1
Technology-Related Intellectual Property [Member]
Intangible Assets [Line Items]
Assigned Value		170.1	174.3
Accumulated amortization		(51)	(46.6)
Net book value		119.1	127.7
Other [Member]
Intangible Assets [Line Items]
Assigned Value		100.9	103.8
Accumulated amortization		(17.3)	(14.9)
Net book value		83.6	88.9
Total Amortizable Intangible Assets [Member]
Intangible Assets [Line Items]
Assigned Value		6,027.6	6,075.2
Accumulated amortization		(1,479.7)	(1,407.5)
Net book value		$ 4,547.9	$ 4,667.7
[1]	) Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the Commodity Futures Trading Commission (CFTC). Product authorizations from the CFTC have no term limits.

Intangible Assets And Goodwil_4

Intangible Assets And Goodwill (Future Estimated Amortization Expense) (Details) $ in Millions	Mar. 31, 2020USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2020	$ 231.7
2021	308.9
2022	308.5
2023	307.2
2024	300.5
2025	300.3
Thereafter	$ 2,790.8

Debt (Schedule Of Short-Term An

Debt (Schedule Of Short-Term And Long-Term Debt) (Details) € in Millions, $ in Millions	1 Months Ended			3 Months Ended
	Mar. 31, 2015	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2020USD ($)	Mar. 31, 2020EUR (€)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Long-term debt				$ 3,539.8		$ 3,743.2
Forward starting interest rate swap agreement fixed rate	3.11%	4.73%	3.32%
$750.0 million Fixed Rate Notes Due September 2022, stated rate of 3.00% [Member]
Debt Instrument [Line Items]
Long-term debt				747.9		747.7
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date				Sep. 15, 2022
Debt Instrument, Interest Rate, Stated Percentage				3.00%	3.00%
€15.0 million fixed rate notes due May 2023 [Member]
Debt Instrument [Line Items]
Long-term debt				$ 16.2		16.4
Debt Instrument, Face Amount | €					€ 15
Debt Instrument, Maturity Date				May 1, 2023
Debt Instrument, Interest Rate, Stated Percentage				4.30%	4.30%
$750.0 Million Fixed Rate Notes Due March 2025, stated rate of 3.00% [Member]
Debt Instrument [Line Items]
Long-term debt				$ 746.5		746.3
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date				Mar. 15, 2025
Debt Instrument, Interest Rate, Stated Percentage				3.00%	3.00%
$500.0 Million Fixed Rate Notes Due June 2028, stated rate of 3.75% [Member] [Domain]
Debt Instrument [Line Items]
Long-term debt				$ 496.5		496.4
Debt Instrument, Face Amount				$ 500
Debt Instrument, Maturity Date				Jun. 15, 2028
Debt Instrument, Interest Rate, Stated Percentage				3.75%	3.75%
$750.0 million Fixed Rate Notes Due September 2043, stated rate of 5.30% [Member]
Debt Instrument [Line Items]
Long-term debt				$ 742.8		742.8
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date				Sep. 15, 2043
Debt Instrument, Interest Rate, Stated Percentage				5.30%	5.30%
$700.0 Million Fixed Rate Notes Due June 2048, stated rate of 4.15% [Member] [Domain] [Domain]
Debt Instrument [Line Items]
Long-term debt				$ 689.9		689.8
Debt Instrument, Face Amount				$ 700
Debt Instrument, Maturity Date				Jun. 15, 2048
Debt Instrument, Interest Rate, Stated Percentage				4.15%	4.15%
Commercial Paper [Member]
Debt Instrument [Line Items]
Long-term debt				$ 100		$ 303.8

Debt (Schedule Of Maturities Of

Debt (Schedule Of Maturities Of Long-Term Debt) (Details) $ in Millions	Mar. 31, 2020USD ($)
Debt Disclosure [Abstract]
2021	$ 0
2022	850
2023	16.6
2024	0
2025	750
Thereafter	$ 1,950

Debt Narrative (details) (Detai

Debt Narrative (details) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)days
Debt Instrument [Line Items]
debt weighted average balance | $	$ 178
Weighted Average Discount Rate, Percent	1.68%
Minimum [Member]
Debt Instrument [Line Items]
commercial paper days outstanding | days	1
Maximum [Member]
Debt Instrument [Line Items]
commercial paper days outstanding | days	18
Commercial Paper [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Debt | $	$ 1,100

Leases (Details)

Leases (Details)	Mar. 31, 2020
Leases [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	18
Lessee, Operating Lease, Renewal Term	5
Lessee, Operating Lease, Option to Terminate	12
Lessee, Operating Lease, Term of Contract	12

Leases Lease Costs (Details)

Leases Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Lease, Cost	$ 14.9	$ 18.4
Short-term Lease, Cost	0.2	3.4
Operating Lease, Expense	15.1	21.8
Finance Lease, Interest Expense	0.9	0.9
Finance Lease, Right-of-Use Asset, Amortization	2.2	2.2
Finance Lease, Expense	3.1	3.1
Sublease Income	$ 3.6	$ 3.3

Leases Supplemental Cash Flow I

Leases Supplemental Cash Flow Information-Leases (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Lease, Payments	$ 15.9	$ 15.2
Finance Lease, Principal Payments	$ 4.2	$ 4.2

Leases Supplemental Balance She

Leases Supplemental Balance Sheet Information-Leases (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Operating Lease, Right-of-Use Asset	$ 406.7	$ 417.1
Operating Lease, Liability, Current	41.6	42.3
Operating Lease, Liability, Noncurrent	496.3	514.8
Operating Lease, Liability	$ 537.9	$ 557.1
Operating Lease, Weighted Average Remaining Lease Term	145 months	146 months
Operating Lease, Weighted Average Discount Rate, Percent	4.00%	4.00%
Finance Lease, Right-of-Use Asset	$ 95.3	$ 97.5
Finance Lease, Liability, Current	7.5	7.4
Finance Lease, Liability, Noncurrent	89.6	91.5
Finance Lease, Liability	$ 97.1	$ 98.9
Finance Lease, Weighted Average Remaining Lease Term	132 months	135 months
Finance Lease, Weighted Average Discount Rate, Percent	3.50%	3.50%

Leases Operating Leases Future

Leases Operating Leases Future Minimum Payments (Details) $ in Millions	Mar. 31, 2020USD ($)
Operating Leases, Future Minimum Payments Due [Line Items]
Remainder of 2020	$ 47.9
2021	61.2
2022	64.2
2023	60.5
2024	55.1
2025	53.5
Thereafter	345.3
Total Operating Lease Payments	687.7
Operating Lease Payments, Less Imputed Interest	(149.8)
Present Value of Operating Lease Liability	$ 537.9

Leases Capital Leases, Future M

Leases Capital Leases, Future Minimum Payments Due (Details) $ in Millions	Mar. 31, 2020USD ($)
Finance Leases, Future Minimum Payments Due [Line Items]
Remainder of 2020	$ 12.7
2021	17
2022	17.1
2023	17.2
2024	17.4
2025	17.5
Thereafter	94.3
Total Finance Lease Payments	193.2
Finance Lease Payments, Less Imputed Interest	(96.1)
Present Value of Finance Lease Liability	$ 97.1

Guarantees (Details)

Guarantees (Details)	3 Months Ended
	Mar. 31, 2020USD ($)years
Guarantor Obligations [Line Items]
Agreement automatic renewal period (in years) | years	1
Contingent liability to SGX, amount of irrevocable letters of credit	$ 310,000,000
Family Farmer and Ranchers Protection Fund [Member]
Guarantor Obligations [Line Items]
Payment per participant	25,000
Payment per cooperative	100,000
FutureLosses	100,000,000
Payments under Guarantee	2,000,000
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 98,000,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Balance	$ 26,128.9	$ 25,965.3
Other comprehensive income (loss), net of tax	(29.6)	(4.5)
Balance	26,567.7	26,186.5
Investment Securities [Member]
Balance	0.8	0.1
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)	(0.6)	0.8
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Income tax benefit (expense)	0.2	(0.2)
Other comprehensive income (loss), net of tax	(0.4)	0.6
Balance	0.4	0.7
Defined Benefit Plans [Member]
Balance	(55.1)	(53.8)
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)	(2)	(2.7)
Amounts reclassified from accumulated other comprehensive income (loss)	1.2	1.2
Income tax benefit (expense)	0.2	0.4
Other comprehensive income (loss), net of tax	(0.6)	(1.1)
Balance	(55.7)	(54.9)
Derivative Investments [Member]
Balance	69	69.7
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)	0	0.3
Amounts reclassified from accumulated other comprehensive income (loss)	(1.8)	(0.3)
Income tax benefit (expense)	0.4	0
Other comprehensive income (loss), net of tax	(1.4)	0
Balance	67.6	69.7
Foreign Currency Translation [Member]
Balance	(11.3)	(10.7)
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)	(27.8)	(4)
Amounts reclassified from accumulated other comprehensive income (loss)	0.6	0
Income tax benefit (expense)	0	0
Other comprehensive income (loss), net of tax	(27.2)	(4)
Balance	(38.5)	(14.7)
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	3.4	5.3
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)	(30.4)	(5.6)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0.9
Income tax benefit (expense)	0.8	0.2
Other comprehensive income (loss), net of tax	(29.6)	(4.5)
Balance	$ (26.2)	$ 0.8

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other than Temporary Impairment Losses, Investments	$ 23.1
Net losses on impaired assets	23.1	$ 0
Other Assets, Fair Value Disclosure	0
Unrealized Gain (Loss) on Investments	2.9
Investments, Fair Value Disclosure	$ 18.3

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - Fair Value, Recurring [Member] $ in Millions	Mar. 31, 2020USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	$ 77.5
Total Assets at Fair Value	3,285.8
Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	17.3
Mutual Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading Securities at Fair Value	59.9
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0.1
Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0.2
U.S. Treasury Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	1,369.9
U.S. Government Agency Security Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	1,838.4
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	77.3
Total Assets at Fair Value	3,285.6
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	17.3
Fair Value, Inputs, Level 1 [Member] | Mutual Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading Securities at Fair Value	59.9
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0.1
Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 1 [Member] | U.S. Treasury Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	1,369.9
Fair Value, Inputs, Level 1 [Member] | U.S. Government Agency Security Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	1,838.4
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	0.2
Total Assets at Fair Value	0.2
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 2 [Member] | Mutual Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading Securities at Fair Value	0
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0.2
Fair Value, Inputs, Level 2 [Member] | U.S. Treasury Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 2 [Member] | U.S. Government Agency Security Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	0
Total Assets at Fair Value	0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 3 [Member] | Mutual Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading Securities at Fair Value	0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 3 [Member] | U.S. Treasury Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0
Fair Value, Inputs, Level 3 [Member] | U.S. Government Agency Security Performance Bond [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	$ 0

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Values of Long-Term Debt) (Details) - 3 months ended Mar. 31, 2020 € in Millions, $ in Millions	USD ($)	EUR (€)
$750.0 million Fixed Rate Notes Due September 2022, stated rate of 3.00% [Member]
Debt Instrument, Face Amount	$ 750
Debt Instrument, Maturity Date	Sep. 15, 2022
€15.0 million fixed rate notes due May 2023 [Member]
Debt Instrument, Face Amount | €		€ 15
Debt Instrument, Maturity Date	May 1, 2023
$750.0 Million Fixed Rate Notes Due March 2025, stated rate of 3.00% [Member]
Debt Instrument, Face Amount	$ 750
Debt Instrument, Maturity Date	Mar. 15, 2025
$500.0 Million Fixed Rate Notes Due June 2028, stated rate of 3.75% [Member] [Domain]
Debt Instrument, Face Amount	$ 500
Debt Instrument, Maturity Date	Jun. 15, 2028
$750.0 million Fixed Rate Notes Due September 2043, stated rate of 5.30% [Member]
Debt Instrument, Face Amount	$ 750
Debt Instrument, Maturity Date	Sep. 15, 2043
$700.0 Million Fixed Rate Notes Due June 2048, stated rate of 4.15% [Member] [Domain] [Domain]
Debt Instrument, Face Amount	$ 700
Debt Instrument, Maturity Date	Jun. 15, 2048
Fair Value, Inputs, Level 2 [Member] | $750.0 million Fixed Rate Notes Due September 2022, stated rate of 3.00% [Member]
Debt Instrument, Fair Value Disclosure	$ 760.7
Debt Instrument, Face Amount	$ 750
Debt Instrument, Maturity Date	Sep. 15, 2022
Fair Value, Inputs, Level 2 [Member] | €15.0 million fixed rate notes due May 2023 [Member]
Debt Instrument, Fair Value Disclosure	$ 17.6
Debt Instrument, Face Amount	$ 15
Debt Instrument, Maturity Date	May 31, 2023
Fair Value, Inputs, Level 2 [Member] | $750.0 Million Fixed Rate Notes Due March 2025, stated rate of 3.00% [Member]
Debt Instrument, Fair Value Disclosure	$ 774.7
Debt Instrument, Face Amount	$ 750
Debt Instrument, Maturity Date	Mar. 15, 2025
Fair Value, Inputs, Level 2 [Member] | $500.0 Million Fixed Rate Notes Due June 2028, stated rate of 3.75% [Member] [Domain]
Debt Instrument, Fair Value Disclosure	$ 560.2
Debt Instrument, Face Amount	$ 500
Debt Instrument, Maturity Date	Jun. 15, 2028
Fair Value, Inputs, Level 2 [Member] | $750.0 million Fixed Rate Notes Due September 2043, stated rate of 5.30% [Member]
Debt Instrument, Fair Value Disclosure	$ 1,095.1
Debt Instrument, Face Amount	$ 750
Debt Instrument, Maturity Date	Sep. 15, 2043
Fair Value, Inputs, Level 2 [Member] | $700.0 Million Fixed Rate Notes Due June 2048, stated rate of 4.15% [Member] [Domain] [Domain]
Debt Instrument, Fair Value Disclosure	$ 918
Debt Instrument, Face Amount	$ 700
Debt Instrument, Maturity Date	Jun. 15, 2048
Fair Value, Inputs, Level 3 [Member] | Commercial Paper [Member]
Debt Instrument, Fair Value Disclosure	$ 100

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	68	76
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	68	76

Earnings Per Share (Net Income

Earnings Per Share (Net Income Attributable To CME Group) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to CME Group	$ 766.2	$ 496.9
Basic (in shares)	357,524	356,886
Effect of stock options, restricted stock and performance shares	931	1,161
Diluted (in shares)	358,455	358,047
Earnings per common share, basic (in dollars per share)	$ 2.14	$ 1.39
Earnings per common share, diluted (in dollars per share)	$ 2.14	$ 1.39