CME (CME) 10-Q 7 Aug 19 2019 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Jun. 30, 2019	Jul. 10, 2019
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
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	Q2
Document Fiscal Year Focus	2019
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		358,092,467
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		Jun. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents		$ 937.7	$ 1,374.5
Marketable securities		81.8	72.9
Accounts receivable, net of allowance of $2.8 and $2.7		593.7	553.3
Other current assets (includes $4.1 and $1.5 in restricted cash)		359.7	430.5
Performance bonds and guaranty fund contributions		32,489.5	39,455.5
Total current assets		34,462.4	41,886.7
Property, net of accumulated depreciation and amortization of $843.6 and $761.1		500.4	448.7
Intangible assets—trading products	[1]	17,175.3	17,175.3
Intangible assets—other, net		5,308.7	5,500.1
Goodwill		10,795.3	10,805.3
Other assets (includes $1.1 and $1.2 in restricted cash)		2,107.4	1,659.6
Total Assets		70,349.5	77,475.7
Liabilities and Equity
Accounts payable		51.6	116
Short-term Debt		0	574.2
Other current liabilities		393.6	1,126.9
Performance bonds and guaranty fund contributions		32,489.5	39,455.5
Total current liabilities		32,934.7	41,272.6
Long-term debt		4,072.9	3,826.8
Deferred income tax liabilities, net		5,645.1	5,665.9
Other liabilities		1,211.9	745.1
Total Liabilities		43,864.6	51,510.4
Shareholders' Equity:
Preferred stock, $0.01 par value, 10,000 shares authorized at June 30, 2019 and December 31, 2018; none issued		0	0
Additional paid-in capital		21,109.2	21,054.3
Retained earnings		5,336.8	4,855.3
Accumulated other comprehensive income (loss)		5.6	5.3
Total CME Group Shareholders’ Equity		26,455.2	25,918.5
Total Liabilities and Equity		70,349.5	77,475.7
Stockholders' Equity Attributable to Noncontrolling Interest		29.7	46.8
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	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable, allowance	$ 2.8	$ 2.7
Short-term restricted cash	4.1	1.5
Accumulated depreciation and amortization, property	843.6	761.1
Long-term restricted cash	$ 1.1	$ 1.2
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)	357,143	356,824
Common stock, shares outstanding (in shares)	357,143	356,824
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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues
Total Revenues	$ 1,272.7	$ 1,059.6	$ 2,452.3	$ 2,168.6
Expenses
Compensation and benefits	227.3	150.8	457.6	303.5
Technology	48.6	25.2	95.7	50.7
Professional fees and outside services	41.7	31.9	81.1	74.5
Amortization of purchased intangibles	76.1	23.6	156.8	47.3
Depreciation and amortization	46.3	27.5	79.2	55.6
Licensing and other fee agreements	44.8	39.9	85.3	89.4
Other	89.3	93.8	167	139.8
Total Expenses	574.1	392.7	1,122.7	760.8
Operating Income	698.6	666.9	1,329.6	1,407.8
Non-Operating Income (Expense)
Investment income	139.3	241.9	318	398.3
Interest and other borrowing costs	(45.1)	(33.1)	(93.2)	(63.2)
Equity in net earnings of unconsolidated subsidiaries	43.8	36.4	84.3	76.5
Other non-operating income (expense)	(134.5)	(155.3)	(296.4)	(273.9)
Total Non-Operating Income (Expense)	3.5	89.9	12.7	137.7
Income before Income Taxes	702.1	756.8	1,342.3	1,545.5
Income tax provision	187.5	190.7	331.8	380.6
Net Income	514.6	566.1	1,010.5	1,164.9
Net (Income) Loss Attributable to Noncontrolling Interest	(0.8)	0	0.2	0
Net Income (Loss) Attributable to CME Group	$ 513.8	$ 566.1	$ 1,010.7	$ 1,164.9
Earnings per Common Share Attributable to CME Group:
Basic (in dollars per share)	$ 1.44	$ 1.67	$ 2.83	$ 3.43
Diluted (in dollars per share)	$ 1.43	$ 1.66	$ 2.82	$ 3.42
Weighted Average Number of Common Shares:
Basic (in shares)	357,060	339,465	356,973	339,386
Diluted (in shares)	358,155	340,872	358,103	340,838
Clearing and transaction fees [Member]
Revenues	$ 1,051.8	$ 906.1	$ 2,004.4	$ 1,879.7
Market data and information services
Revenues	128.3	113.8	258.4	208.7
Other
Revenues	$ 92.6	$ 39.7	$ 189.5	$ 80.2

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 514.6	$ 566.1	$ 1,010.5	$ 1,164.9
Other comprehensive income (loss), net of tax:
Net unrealized holding gains (losses) arising during the period	0.9	0	1.7	(0.9)
Reclassification of net (gains) losses on sales included in investment income	(0.1)	0	(0.1)	0
Income tax benefit (expense)	(0.2)	0	(0.4)	0.2
Investment securities, net	0.6	0	1.2	(0.7)
Net change in defined benefit plans arising during the period	0	0	(2.7)	1.7
Amortization of net actuarial (gains) losses included in compensation and benefits expense	1.2	0.6	2.4	1.3
Income tax benefit (expense)	(0.3)	(0.2)	0.1	(0.8)
Defined benefit plans, net	0.9	0.4	(0.2)	2.2
Net unrealized holding gains (losses) during the period	(0.5)	0	(0.2)	0
Amortization of effective portion of net (gains) losses on cash flow hedges included in interest expense	(0.3)	(0.3)	(0.6)	(0.6)
Income tax benefit (expense)	0.1	0.1	0.1	0.2
Derivative investments, net	(0.7)	(0.2)	(0.7)	(0.4)
Foreign currency translation adjustments	1	(1.5)	(3)	(0.6)
Income tax benefit (expense)	3	0	3	0
Foreign currency translation, net	4	(1.5)	0	(0.6)
Other comprehensive income (loss), net of tax	4.8	(1.3)	0.3	0.5
Comprehensive Income	519.4	564.8	1,010.8	1,165.4
Comprehensive (Income) Loss Attributable to Noncontrolling Interest	(0.8)	0	0.2	0
Comprehensive Income attributable to CME Group	$ 518.6	$ 564.8	$ 1,011	$ 1,165.4

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, 2017								339,235		3
Balance at Dec. 31, 2017	$ 22,411.8	$ 17,900.3	$ 4,497.2	$ 14.3
Net Income (Loss) Attributable to CME Group	1,164.9
Net (Income) Loss Attributable to Noncontrolling Interest	0
Net Income	1,164.9		1,164.9
Other comprehensive income (loss), net of tax	0.5			0.5
Dividends on common stock	(476.3)		(476.3)
Impact of adoption of standards update	(8.7)		(12.5)	3.8
Exercise of stock options, shares								116
Exercise of stock options	8.2	8.2
Vesting of issued restricted Class A common stock, shares								145
Vesting of issued restricted Class A common stock	(14.9)	(14.9)
Stock Issued To Related Parties During Period Shares								14
Stock Issued To Related Parties During Period Value	2.4	2.4
Stock Issued During Period, Shares, Employee Stock Purchase Plans								10
Stock Issued During Period, Value, Employee Stock Purchase Plan	1.8	1.8
Stock-based compensation	33.9	33.9
Balance (in shares) at Jun. 30, 2018								339,520		3
Balance at Jun. 30, 2018	23,123.6	17,931.7	5,173.3	18.6
Balance (in shares) at Mar. 31, 2018								339,435		3
Balance at Mar. 31, 2018	22,772.8	17,907.5	4,845.4	19.9
Net Income (Loss) Attributable to CME Group	566.1
Net (Income) Loss Attributable to Noncontrolling Interest	0
Net Income	566.1		566.1
Other comprehensive income (loss), net of tax	(1.3)			(1.3)
Dividends on common stock	(238.2)		(238.2)
Exercise of stock options, shares								57
Exercise of stock options	4	4
Vesting of issued restricted Class A common stock, shares								4
Vesting of issued restricted Class A common stock	(0.2)	(0.2)
Stock Issued To Related Parties During Period Shares								14
Stock Issued To Related Parties During Period Value	2.4	2.4
Stock Issued During Period, Shares, Employee Stock Purchase Plans								10
Stock Issued During Period, Value, Employee Stock Purchase Plan	1.8	1.8
Stock-based compensation	16.2	16.2
Balance (in shares) at Jun. 30, 2018								339,520		3
Balance at Jun. 30, 2018	23,123.6	17,931.7	5,173.3	18.6
Balance (in shares) at Dec. 31, 2018							356,824	356,824	3	3
Balance at Dec. 31, 2018	25,918.5	21,057.9	4,855.3	5.3	$ 25,918.5
Balance at Dec. 31, 2018						$ 46.8
Balance at Dec. 31, 2018	25,965.3
Net Income (Loss) Attributable to CME Group	1,010.7		1,010.7		1,010.7
Net (Income) Loss Attributable to Noncontrolling Interest	0.2					(0.2)
Net Income	1,010.5
Other comprehensive income (loss), net of tax	0.3			0.3	0.3
Dividends on common stock	(536.1)		(536.1)		(536.1)
Impact of adoption of standards update	6.9		6.9		6.9
Changes in non-controlling interest due to measurement period adjustments	(16.9)					(16.9)
Exercise of stock options, shares								162
Exercise of stock options	7	7			7
Vesting of issued restricted Class A common stock, shares								128
Vesting of issued restricted Class A common stock	(14.1)	(14.1)			(14.1)
Stock Issued To Related Parties During Period Shares								16
Stock Issued To Related Parties During Period Value	3.1	3.1			3.1
Stock Issued During Period, Shares, Employee Stock Purchase Plans								13
Stock Issued During Period, Value, Employee Stock Purchase Plan	2.5	2.5			2.5
Stock-based compensation	56.4	56.4			56.4
Balance (in shares) at Jun. 30, 2019							357,143	357,143	3	3
Balance at Jun. 30, 2019	26,455.2	21,112.8	5,336.8	5.6	26,455.2
Balance at Jun. 30, 2019						29.7
Balance at Jun. 30, 2019	26,484.9
Balance (in shares) at Mar. 31, 2019								357,013		3
Balance at Mar. 31, 2019		21,065.7	5,091.1	0.8	26,157.6
Balance at Mar. 31, 2019						28.9
Balance at Mar. 31, 2019	26,186.5
Net Income (Loss) Attributable to CME Group	513.8				513.8
Net (Income) Loss Attributable to Noncontrolling Interest	(0.8)					0.8
Net Income	514.6
Other comprehensive income (loss), net of tax	4.8			4.8	4.8
Dividends on common stock	(268.1)		(268.1)		(268.1)
Exercise of stock options, shares								98
Exercise of stock options	3.7	3.7			3.7
Vesting of issued restricted Class A common stock, shares								3
Vesting of issued restricted Class A common stock	(0.3)	(0.3)			(0.3)
Stock Issued To Related Parties During Period Shares								16
Stock Issued To Related Parties During Period Value	3.1	3.1			3.1
Stock Issued During Period, Shares, Employee Stock Purchase Plans								13
Stock Issued During Period, Value, Employee Stock Purchase Plan	2.5	2.5			2.5
Stock-based compensation	38.1	38.1			38.1
Balance (in shares) at Jun. 30, 2019							357,143	357,143	3	3
Balance at Jun. 30, 2019	26,455.2	$ 21,112.8	$ 5,336.8	$ 5.6	$ 26,455.2
Balance at Jun. 30, 2019						$ 29.7
Balance at Jun. 30, 2019	$ 26,484.9

Consolidated Statements Of Sh_2

Consolidated Statements Of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends on common stock, per share (in dollars per share)	$ 0.75	$ 0.70	$ 1.50	$ 1.40

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities
Net Income	$ 1,010.5	$ 1,164.9
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	56.4	33.9
Amortization of purchased intangibles	156.8	47.3
Depreciation and amortization	79.2	55.6
Unrealized loss on assets held for sale	21.6	0
Net loss on derivatives	16.7	36.9
Net realized and unrealized (gains) losses on privately-held equity investments	27.2	(88.2)
Undistributed net earnings of unconsolidated subsidiaries	(31.2)	(4.7)
Deferred income taxes	(13.1)	5
Change in:
Accounts receivable	(40.4)	(75)
Other current assets	126.1	36.5
Other assets	(13.4)	(0.8)
Accounts payable	(64.3)	(3.5)
Income taxes payable	(28.6)	171
Other current liabilities	(177.7)	(26.4)
Other liabilities	8.5	(5.9)
Other	8.6	1.2
Net Cash Provided by (Used in) Operating Activities	1,142.9	1,347.8
Cash Flows from Investing Activities
Proceeds from maturities of available-for-sale marketable securities	11.6	3.4
Purchases of available-for-sale marketable securities	(8.3)	(1.9)
Purchases of property, net	(121.6)	(29.6)
Proceeds from sales of privately-held equity investments	28.4	20.4
Net Cash Used in Investing Activities	(89.9)	(7.7)
Cash Flows from Financing Activities
Issuance of commercial paper, net of maturities	239.5	0
Proceeds from debt, net of issuance costs	0	1,187.2
Repayments of debt	569.2	0
Cash dividends	(1,159.9)	(1,662.5)
Premium payment for derivative contract	0	(30)
Settlement of derivative contracts	(16)	0
Employee taxes paid on restricted stock vesting	(14.1)	(14.9)
Other	0.4	9.9
Net Cash Used in Financing Activities	(1,487.3)	(510.3)
Net change in cash, cash equivalents and restricted cash	(434.3)	829.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, beginning balance	1,377.2	1,906
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, ending balance	942.9	2,735.8
Cash and cash equivalents	937.7	1,098.9
Short-term restricted cash	4.1	1,635.5
Long-term restricted cash	1.1	1.4
Income taxes paid	373.9	272.8
Interest paid	$ 80.1	$ 42.4

Basis Of Presentation

Basis Of Presentation	6 Months Ended
	Jun. 30, 2019
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. Effective November 2, 2018, CME Group completed its acquisition of NEX. NEX offers electronic trade execution platforms for the foreign exchange and fixed income over-the-counter markets as well as other services across the transaction lifecycle, including trade and portfolio management and portfolio compression. The financial statements and accompanying notes presented in this report include the financial results of NEX and its subsidiaries beginning on November 3, 2018. 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 June 30, 2019 and December 31, 2018 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, 2018 , filed with the Securities and Exchange Commission (SEC) on February 28, 2019.

Accounting Policies (Notes)

Accounting Policies (Notes)	6 Months Ended
	Jun. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Changes [Text Block]	Accounting Policies Newly Adopted Accounting Policies. In February 2016, the FASB issued a standards update that requires lessees to recognize on the balance sheet the assets and liabilities associated with the rights and obligations created by those leases. The guidance for lessors is largely unchanged from current accounting rules. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current accounting standards, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. The company implemented this standard as of January 1, 2019 using the modified retrospective approach with a cumulative effect of initially applying the guidance recognized on the date of initial adoption. Upon adoption of the new standard on January 1, 2019, the company recognized a lease liability of $568.0 million and right-of-use asset of $448.2 million . Recently Issued Accounting Pronouncements. 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 standard is effective for reporting periods beginning after December 15, 2019. The standard’s provisions must be applied as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. Early adoption is permitted for reporting periods beginning in 2019. The company does not believe that the adoption of this guidance in 2020 will have a material impact on the consolidated financial statements. 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)	6 Months Ended
	Jun. 30, 2019
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 access and communication fees, fees for collateral management, fees for trade order routing through agreements from various strategic relationships, as well as other post-trade services to customers and clearing firms. 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 CME 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 and six months ended June 30, 2019 and 2018: Quarter Ended Six Months Ended June 30, (in millions) 2019 2018 2019 2018 Interest rates $ 347.4 $ 288.9 $ 650.2 $ 627.3 Equity indexes 148.1 157.3 294.0 352.3 Foreign exchange 39.3 49.1 80.5 100.2 Agricultural commodities 141.5 141.4 246.5 262.5 Energy 179.3 192.0 344.3 383.6 Metals 58.1 60.5 109.1 119.9 Cash markets business 120.7 — 243.6 — Interest rate swap 17.4 16.9 36.2 33.9 Total clearing and transaction fees 1,051.8 906.1 2,004.4 1,879.7 Market data and information services 128.3 113.8 258.4 208.7 Other 92.6 39.7 189.5 80.2 Total revenues $ 1,272.7 $ 1,059.6 $ 2,452.3 $ 2,168.6 Timing of Revenue Recognition Services transferred at a point in time 988.1 890.6 $ 1,881.0 $ 1,848.4 Services transferred over time 281.9 166.7 559.6 315.5 One-time charges and miscellaneous revenues 2.7 2.3 11.7 4.7 Total revenues $ 1,272.7 $ 1,059.6 $ 2,452.3 $ 2,168.6 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 reported 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 six months ended June 30, 2019 were not materially impacted by any other factors. The balance of contract liabilities was $57.9 million and $44.4 million as of June 30, 2019 and December 31, 2018

Performance Bonds and Guaranty

Performance Bonds and Guaranty Fund Contributions (Notes)	6 Months Ended
	Jun. 30, 2019
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. 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 June 30, 2019 , CME maintained $16.7 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 six months of 2019, the clearing house transferred an average of approximately $3.1 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 June 30, 2019

Intangible Assets And Goodwill

Intangible Assets And Goodwill	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets And Goodwill	Intangible Assets Intangible assets consisted of the following at June 30, 2019 and December 31, 2018 : June 30, 2019 December 31, 2018 (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 $ 5,828.1 $ (1,206.2 ) $ 4,621.9 $ 5,862.5 $ (1,065.6 ) $ 4,796.9 Technology-related intellectual property 178.7 (36.2 ) 142.5 179.1 (25.6 ) 153.5 Other 103.3 (9.0 ) 94.3 102.8 (3.1 ) 99.7 Total amortizable intangible assets $ 6,110.1 $ (1,251.4 ) 4,858.7 $ 6,144.4 $ (1,094.3 ) 5,050.1 Indefinite-Lived Intangible Assets: Trade names 450.0 450.0 Total intangible assets – other, net $ 5,308.7 $ 5,500.1 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 $76.1 million and $23.6 million for the quarters ended June 30, 2019 and 2018 , respectively. Total amortization expense for intangible assets was $156.8 million and $47.3 million for the six months ended June 30, 2019 and 2018 , respectively. As of June 30, 2019 , the future estimated amortization expense related to amortizable intangible assets is expected to be as follows: (in millions) Amortization Expense Remainder of 2019 $ 157.8 2020 315.5 2021 315.4 2022 315.0 2023 313.6 2024 307.0 Thereafter 3,134.4 Goodwill activity consisted of the following at June 30, 2019 and December 31, 2018 : (in millions) Balance at December 31, 2018 Business Combinations Other Activity (1) Balance at June 30, 2019 CBOT Holdings $ 5,066.4 $ — $ — $ 5,066.4 NYMEX Holdings 2,462.2 — — 2,462.2 NEX 3,236.3 — (10.0 ) 3,226.3 Other 40.4 — — 40.4 Total Goodwill $ 10,805.3 $ — $ (10.0 ) $ 10,795.3 (in millions) Balance at December 31, 2017 Business Other Balance at December 31, 2018 CBOT Holdings $ 5,066.4 $ — $ — $ 5,066.4 NYMEX Holdings 2,462.2 — — 2,462.2 NEX — 3,236.3 — 3,236.3 Other 40.4 — — 40.4 Total Goodwill $ 7,569.0 $ 3,236.3 $ — $ 10,805.3

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt In March 2019, the company repaid both the €350.0 million fixed rates notes and the ¥19.1 billion term loan. Short-term debt outstanding consisted of the following at June 30, 2019 and December 31, 2018 (in U.S. dollar equivalent): (in millions) June 30, 2019 December 31, 2018 €350.0 million fixed rate notes due March 2019, stated rate of 3.13% $ — $ 400.7 ¥19.1 billion term loan due March 2019, stated rate of 0.81% — 173.5 Total short-term debt $ — $ 574.2 Long-term debt consisted of the following at June 30, 2019 and December 31, 2018 : (in millions) June 30, 2019 December 31, 2018 $750.0 million fixed rate notes due September 2022, stated rate of 3.00% (1) $ 747.3 $ 746.9 €15.0 million fixed rate notes due May 2023, stated rate of 4.30% 16.6 16.6 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (2) 745.9 745.6 $500.0 million fixed rate notes due June 2028, stated rate of 3.75% 496.1 495.9 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (3) 742.6 742.4 $700.0 million fixed rate notes due June 2048, stated rate of 4.15% 689.7 689.5 Commercial paper (4) 634.7 389.9 Total long-term debt $ 4,072.9 $ 3,826.8 (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 $6.9 billion and maturities ranging from 1 to 18 days was issued during the first six months of 2019. The weighted average discount rate of commercial paper outstanding at June 30, 2019 was 2.40% . The weighted average balance of commercial paper outstanding during the first six months of 2019 was $468.8 million . Long-term debt maturities, at par value (in U.S. dollar equivalent), were as follows at June 30, 2019 : (in millions) Par Value 2020 $ — 2021 — 2022 1,385.0 2023 17.1 2024 — Thereafter 2,700.0 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	6 Months Ended
	Jun. 30, 2019
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. NYMEX’s motion to dismiss was denied in 2014. 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 Court granted CBOT's and CME's motion for summary judgment and dismissed the case in its entirety. Eurex has appealed this decision. 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 June 30, 2019 and December 31, 2018 . Intellectual Property Indemnifications . Certain agreements with customers and other third parties related to accessing CME Group’s services may contain indemnifications from intellectual property claims that may be made against them as a result of their use of the applicable services. The potential future claims relating to these indemnifications cannot be estimated and therefore no liability has been recorded.

Leases (Notes)

Leases (Notes)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee, Leases [Policy Text Block]	Leases The company adopted the new leasing standard on January 1, 2019, using the modified retrospective approach. The standard requires lessees to recognize on the balance sheet the assets and liabilities associated with the rights and obligations created by those leases. Upon implementation of the standard, the company utilized the package of practical expedients which did not require reassessment of the following: (a) whether any expired or existing contracts are or contain leases, (b) the lease classification for any expired or existing leases, and (c) any initial direct costs for existing leases. In addition, the company has elected not to separately account for lease and non-lease components, resulting in a greater amount of capitalized lease costs on the balance sheet. Upon adoption of the new standard on January 1, 2019, the company recognized a lease liability of $568.0 million and right-of-use asset of $448.2 million . The company has operating leases for datacenters, corporate offices, and certain information technology equipment. The operating leases have remaining lease terms of up to 19 years, some of which include options to extend or renew the leases for up to an additional 5 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 three finance leases, one of 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. We have two other finance leases related to networking equipment and connectivity hardware. These leases qualify for classification as finance leases due to our exercise of an existing purchase option on this equipment. 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 company has elected to utilize the short term lease exception for purposes of adopting this standard, such that the company has not capitalized on the balance sheet a lease asset or lease liability associated with leases with terms of 12 months or less from the commencement date. The components of lease costs were as follows: (in millions) Quarter Ended June 30, 2019 Six Months Ended June 30, 2019 Operating lease expense: Operating lease cost $ 18.9 $ 37.3 Short-term lease cost 1.5 4.9 Total operating lease expense included in other expense $ 20.4 $ 42.2 Finance lease expense: Interest expense $ 0.9 $ 1.8 Depreciation expense 2.4 4.6 Total finance lease expense $ 3.3 $ 6.4 Sublease revenue included in other revenue $ 1.7 $ 5.3 Supplemental cash flow information related to leases was as follows: (in millions) Quarter Ended Six Months Ended Cash outflows for operating leases $ 16.9 $ 32.1 Cash outflows for finance leases 4.8 9.0 Supplemental balance sheet information related to leases was as follows: Operating leases (in millions) June 30, 2019 Operating lease right-of-use assets $ 433.5 Operating lease liabilities: Other current liabilities $ 41.3 Other liabilities 524.3 Total operating lease liabilities $ 565.6 Weighted average remaining lease term (in months) 151 Weighted average discount rate 4.0 % Finance leases (in millions) June 30, 2019 Finance lease right-of-use assets $ 102.9 Finance lease liabilities: Other current liabilities $ 8.9 Other liabilities 95.2 Total finance lease liabilities $ 104.1 Weighted average remaining lease term (in months) 140 Weighted average discount rate 3.5 % Future minimum lease payments were as follows as of June 30, 2019 for operating and finance leases: (in millions) Operating Leases Remainder of 2019 $ 31.5 2020 63.3 2021 60.1 2022 62.9 2023 59.0 2024 53.4 Thereafter 399.0 Total lease payments 729.2 Less: imputed interest (163.6 ) Present value of lease liability $ 565.6 (in millions) Finance Leases Remainder of 2019 $ 9.9 2020 16.9 2021 17.0 2022 17.1 2023 17.2 2024 17.4 Thereafter 111.8 Total lease payments 207.3 Less: imputed interest (103.2 ) Present value of lease liability $ 104.1

Guarantees

Guarantees	6 Months Ended
	Jun. 30, 2019
Guarantees [Abstract]
Guarantees	Guarantees Mutual Offset Agreement. CME and Singapore Exchange Limited (SGX) have a mutual offset agreement with a current term through October 2019. 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 June 30, 2019 , CME was contingently liable to SGX on letters of credit totaling $335.0 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 June 30, 2019 . 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 June 30, 2019

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Notes)	6 Months Ended
	Jun. 30, 2019
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, 2018 $ 0.1 $ (53.8 ) $ 69.7 $ (10.7 ) $ 5.3 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) 1.7 (2.7 ) (0.2 ) (3.0 ) (4.2 ) Amounts reclassified from accumulated other comprehensive income (loss) (0.1 ) 2.4 (0.6 ) — 1.7 Income tax benefit (expense) (0.4 ) 0.1 0.1 3.0 2.8 Net current period other comprehensive income (loss) 1.2 (0.2 ) (0.7 ) — 0.3 Balance at June 30, 2019 $ 1.3 $ (54.0 ) $ 69.0 $ (10.7 ) $ 5.6 (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2017 $ 0.6 $ (36.1 ) $ 58.0 $ (8.2 ) $ 14.3 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) (0.9 ) 1.7 — (0.6 ) 0.2 Amounts reclassified from accumulated other comprehensive income (loss) — 1.3 (0.6 ) — 0.7 Income tax benefit (expense) 0.2 (0.8 ) 0.2 — (0.4 ) Net current period other comprehensive income (loss) (0.7 ) 2.2 (0.4 ) (0.6 ) 0.5 Impact of adoption of standards update on tax effects related to accumulated other comprehensive income 0.1 (8.2 ) 11.9 — 3.8 Balance at June 30, 2018 $ — $ (42.1 ) $ 69.5 $ (8.8 ) $ 18.6

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
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 and corporate debt 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, derivatives 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 derivative contracts were measured at fair value using standard valuation models with market-based observable inputs. Gains and losses on these contracts are recognized in other non-operating income (expense) and accumulated comprehensive income. The fair values of the long-term debt notes were based on quoted market prices in an inactive market. Level 3 liabilities include contingent consideration. The contingent consideration liabilities are considered level 3 liabilities because management used significant unobservable inputs, including probability factors. Changes to the probability assumption do not have a material impact on the fair value of the liability. Level 3 assets also include fixed assets and privately-held equity investments that were impaired. Recurring Fair Value Measurements. Financial assets and liabilities recorded in the consolidated balance sheet as of June 30, 2019 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: June 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 18.4 $ — $ — $ 18.4 Mutual funds 63.0 — — 63.0 Equity securities 0.1 — — 0.1 Asset-backed securities — 0.3 — 0.3 Total Marketable Securities 81.5 0.3 — 81.8 Total Assets at Fair Value $ 81.5 $ 0.3 $ — $ 81.8 Liabilities at Fair Value: Derivative contracts $ — $ 2.4 $ — $ 2.4 Contingent consideration — — 0.5 0.5 Total Liabilities at Fair Value $ — $ 2.4 $ 0.5 $ 2.9 The following is a reconciliation of the level 3 liability valued at fair value on a recurring basis during the first six months of 2019: (in millions) Contingent Consideration Fair value of liability at December 31, 2018 $ 6.7 Unrealized gains (losses) included in operating expense 0.1 Goodwill measurement period adjustment (6.1 ) Settlements (0.2 ) Fair Value of Liability at June 30, 2019 $ 0.5 Non-Recurring Fair Value Measurements. During the first six months of 2019, the company recognized an impairment charge of $18.7 million related to three of its privately-held equity investments. The fair value of two of the investments was estimated to be zero at the impairment date and the fair value of the other investment was estimated to be $0.9 million at the impairment date. The company also recognized unrealized losses of $21.6 million related to assets held for sale and $12.3 million related to certain fixed assets. The fair value of the fixed assets was estimated to be zero at the impairment date. The fair value of the net assets held for sale were estimated to be $3.6 million at June 30, 2019. These assessments were based on quantitative and qualitative indications of impairment. The fair value measurements of the investment, fixed assets and assets held for sale 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 June 30, 2019 , 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 $ 769.7 Level 2 €15.0 million fixed rate notes due May 2023 19.2 Level 2 $750.0 million fixed rate notes due March 2025 780.2 Level 2 $500.0 million fixed rate notes due June 2028 543.6 Level 2 $750.0 million fixed rate notes due September 2043 960.4 Level 2 $700.0 million fixed rate notes due June 2048 787.1 Level 2 Commercial paper 634.7 Level 3

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
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 restricted stock and performance share awards were as follows for the periods presented: Quarter Ended Six Months Ended (in thousands) 2019 2018 2019 2018 Restricted stock and performance shares 55 7 55 9 Total 55 7 55 9 The following table presents the earnings per share calculation for the periods presented: Quarter Ended Six Months Ended 2019 2018 2019 2018 Net Income Attributable to CME Group (in millions) $ 513.8 $ 566.1 $ 1,010.7 $ 1,164.9 Weighted Average Number of Common Shares (in thousands): Basic 357,060 339,465 356,973 339,386 Effect of stock options, restricted stock and performance shares 1,095 1,407 1,130 1,452 Diluted 358,155 340,872 358,103 340,838 Earnings per Common Share Attributable to CME Group: Basic $ 1.44 $ 1.67 $ 2.83 $ 3.43 Diluted 1.43 1.66 2.82 3.42

Subsequent Events (Notes)

Subsequent Events (Notes)	6 Months Ended
	Jun. 30, 2019
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Events The 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)	6 Months Ended
	Jun. 30, 2019
Revenue Recognition [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table represents a disaggregation of revenue from contracts with customers for the quarters and six months ended June 30, 2019 and 2018: Quarter Ended Six Months Ended June 30, (in millions) 2019 2018 2019 2018 Interest rates $ 347.4 $ 288.9 $ 650.2 $ 627.3 Equity indexes 148.1 157.3 294.0 352.3 Foreign exchange 39.3 49.1 80.5 100.2 Agricultural commodities 141.5 141.4 246.5 262.5 Energy 179.3 192.0 344.3 383.6 Metals 58.1 60.5 109.1 119.9 Cash markets business 120.7 — 243.6 — Interest rate swap 17.4 16.9 36.2 33.9 Total clearing and transaction fees 1,051.8 906.1 2,004.4 1,879.7 Market data and information services 128.3 113.8 258.4 208.7 Other 92.6 39.7 189.5 80.2 Total revenues $ 1,272.7 $ 1,059.6 $ 2,452.3 $ 2,168.6 Timing of Revenue Recognition Services transferred at a point in time 988.1 890.6 $ 1,881.0 $ 1,848.4 Services transferred over time 281.9 166.7 559.6 315.5 One-time charges and miscellaneous revenues 2.7 2.3 11.7 4.7 Total revenues $ 1,272.7 $ 1,059.6 $ 2,452.3 $ 2,168.6

Intangible Assets And Goodwill

Intangible Assets And Goodwill (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Components of intangible assets	Intangible assets consisted of the following at June 30, 2019 and December 31, 2018 : June 30, 2019 December 31, 2018 (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 $ 5,828.1 $ (1,206.2 ) $ 4,621.9 $ 5,862.5 $ (1,065.6 ) $ 4,796.9 Technology-related intellectual property 178.7 (36.2 ) 142.5 179.1 (25.6 ) 153.5 Other 103.3 (9.0 ) 94.3 102.8 (3.1 ) 99.7 Total amortizable intangible assets $ 6,110.1 $ (1,251.4 ) 4,858.7 $ 6,144.4 $ (1,094.3 ) 5,050.1 Indefinite-Lived Intangible Assets: Trade names 450.0 450.0 Total intangible assets – other, net $ 5,308.7 $ 5,500.1 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 June 30, 2019 , the future estimated amortization expense related to amortizable intangible assets is expected to be as follows: (in millions) Amortization Expense Remainder of 2019 $ 157.8 2020 315.5 2021 315.4 2022 315.0 2023 313.6 2024 307.0 Thereafter 3,134.4
Goodwill [Line Items]
Goodwill Disclosure [Text Block]	Goodwill activity consisted of the following at June 30, 2019 and December 31, 2018 : (in millions) Balance at December 31, 2018 Business Combinations Other Activity (1) Balance at June 30, 2019 CBOT Holdings $ 5,066.4 $ — $ — $ 5,066.4 NYMEX Holdings 2,462.2 — — 2,462.2 NEX 3,236.3 — (10.0 ) 3,226.3 Other 40.4 — — 40.4 Total Goodwill $ 10,805.3 $ — $ (10.0 ) $ 10,795.3 (in millions) Balance at December 31, 2017 Business Other Balance at December 31, 2018 CBOT Holdings $ 5,066.4 $ — $ — $ 5,066.4 NYMEX Holdings 2,462.2 — — 2,462.2 NEX — 3,236.3 — 3,236.3 Other 40.4 — — 40.4 Total Goodwill $ 7,569.0 $ 3,236.3 $ — $ 10,805.3

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Short-term Debt [Line Items]
Schedule of Short-term Debt [Table Text Block]	Short-term debt outstanding consisted of the following at June 30, 2019 and December 31, 2018 (in U.S. dollar equivalent): (in millions) June 30, 2019 December 31, 2018 €350.0 million fixed rate notes due March 2019, stated rate of 3.13% $ — $ 400.7 ¥19.1 billion term loan due March 2019, stated rate of 0.81% — 173.5 Total short-term debt $ — $ 574.2
Schedule Of Short-Term And Long-Term Debt	Long-term debt consisted of the following at June 30, 2019 and December 31, 2018 : (in millions) June 30, 2019 December 31, 2018 $750.0 million fixed rate notes due September 2022, stated rate of 3.00% (1) $ 747.3 $ 746.9 €15.0 million fixed rate notes due May 2023, stated rate of 4.30% 16.6 16.6 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (2) 745.9 745.6 $500.0 million fixed rate notes due June 2028, stated rate of 3.75% 496.1 495.9 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (3) 742.6 742.4 $700.0 million fixed rate notes due June 2048, stated rate of 4.15% 689.7 689.5 Commercial paper (4) 634.7 389.9 Total long-term debt $ 4,072.9 $ 3,826.8 (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.
Long-term debt maturities at par value	Long-term debt maturities, at par value (in U.S. dollar equivalent), were as follows at June 30, 2019 : (in millions) Par Value 2020 $ — 2021 — 2022 1,385.0 2023 17.1 2024 — Thereafter 2,700.0

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Lease, Cost [Table Text Block]	The components of lease costs were as follows: (in millions) Quarter Ended June 30, 2019 Six Months Ended June 30, 2019 Operating lease expense: Operating lease cost $ 18.9 $ 37.3 Short-term lease cost 1.5 4.9 Total operating lease expense included in other expense $ 20.4 $ 42.2 Finance lease expense: Interest expense $ 0.9 $ 1.8 Depreciation expense 2.4 4.6 Total finance lease expense $ 3.3 $ 6.4 Sublease revenue included in other revenue $ 1.7 $ 5.3
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Supplemental cash flow information related to leases was as follows: (in millions) Quarter Ended Six Months Ended Cash outflows for operating leases $ 16.9 $ 32.1 Cash outflows for finance leases 4.8 9.0
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future minimum lease payments were as follows as of June 30, 2019 for operating and finance leases: (in millions) Operating Leases Remainder of 2019 $ 31.5 2020 63.3 2021 60.1 2022 62.9 2023 59.0 2024 53.4 Thereafter 399.0 Total lease payments 729.2 Less: imputed interest (163.6 ) Present value of lease liability $ 565.6
Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]	(in millions) Finance Leases Remainder of 2019 $ 9.9 2020 16.9 2021 17.0 2022 17.1 2023 17.2 2024 17.4 Thereafter 111.8 Total lease payments 207.3 Less: imputed interest (103.2 ) Present value of lease liability $ 104.1
Property Subject to Operating Lease [Member]
Lessee, Lease, Description [Line Items]
Schedule of Amounts Recognized in Balance Sheet [Table Text Block]	Supplemental balance sheet information related to leases was as follows: Operating leases (in millions) June 30, 2019 Operating lease right-of-use assets $ 433.5 Operating lease liabilities: Other current liabilities $ 41.3 Other liabilities 524.3 Total operating lease liabilities $ 565.6 Weighted average remaining lease term (in months) 151 Weighted average discount rate 4.0 %
Property Subject to Finance Lease [Member]
Lessee, Lease, Description [Line Items]
Schedule of Amounts Recognized in Balance Sheet [Table Text Block]	Finance leases (in millions) June 30, 2019 Finance lease right-of-use assets $ 102.9 Finance lease liabilities: Other current liabilities $ 8.9 Other liabilities 95.2 Total finance lease liabilities $ 104.1 Weighted average remaining lease term (in months) 140 Weighted average discount rate 3.5 %

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2019
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, 2018 $ 0.1 $ (53.8 ) $ 69.7 $ (10.7 ) $ 5.3 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) 1.7 (2.7 ) (0.2 ) (3.0 ) (4.2 ) Amounts reclassified from accumulated other comprehensive income (loss) (0.1 ) 2.4 (0.6 ) — 1.7 Income tax benefit (expense) (0.4 ) 0.1 0.1 3.0 2.8 Net current period other comprehensive income (loss) 1.2 (0.2 ) (0.7 ) — 0.3 Balance at June 30, 2019 $ 1.3 $ (54.0 ) $ 69.0 $ (10.7 ) $ 5.6 (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2017 $ 0.6 $ (36.1 ) $ 58.0 $ (8.2 ) $ 14.3 Other comprehensive income (loss) before reclassifications and income tax benefit (expense) (0.9 ) 1.7 — (0.6 ) 0.2 Amounts reclassified from accumulated other comprehensive income (loss) — 1.3 (0.6 ) — 0.7 Income tax benefit (expense) 0.2 (0.8 ) 0.2 — (0.4 ) Net current period other comprehensive income (loss) (0.7 ) 2.2 (0.4 ) (0.6 ) 0.5 Impact of adoption of standards update on tax effects related to accumulated other comprehensive income 0.1 (8.2 ) 11.9 — 3.8 Balance at June 30, 2018 $ — $ (42.1 ) $ 69.5 $ (8.8 ) $ 18.6

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 18.4 $ — $ — $ 18.4 Mutual funds 63.0 — — 63.0 Equity securities 0.1 — — 0.1 Asset-backed securities — 0.3 — 0.3 Total Marketable Securities 81.5 0.3 — 81.8 Total Assets at Fair Value $ 81.5 $ 0.3 $ — $ 81.8 Liabilities at Fair Value: Derivative contracts $ — $ 2.4 $ — $ 2.4 Contingent consideration — — 0.5 0.5 Total Liabilities at Fair Value $ — $ 2.4 $ 0.5 $ 2.9
Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis [Table Text Block]	The following is a reconciliation of the level 3 liability valued at fair value on a recurring basis during the first six months of 2019: (in millions) Contingent Consideration Fair value of liability at December 31, 2018 $ 6.7 Unrealized gains (losses) included in operating expense 0.1 Goodwill measurement period adjustment (6.1 ) Settlements (0.2 ) Fair Value of Liability at June 30, 2019 $ 0.5
Fair value of Debt Instruments	At June 30, 2019 , 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 $ 769.7 Level 2 €15.0 million fixed rate notes due May 2023 19.2 Level 2 $750.0 million fixed rate notes due March 2025 780.2 Level 2 $500.0 million fixed rate notes due June 2028 543.6 Level 2 $750.0 million fixed rate notes due September 2043 960.4 Level 2 $700.0 million fixed rate notes due June 2048 787.1 Level 2 Commercial paper 634.7 Level 3

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Anti-dilutive restricted stock and performance share awards were as follows for the periods presented: Quarter Ended Six Months Ended (in thousands) 2019 2018 2019 2018 Restricted stock and performance shares 55 7 55 9 Total 55 7 55 9
Basic And Diluted Earnings Per Share	The following table presents the earnings per share calculation for the periods presented: Quarter Ended Six Months Ended 2019 2018 2019 2018 Net Income Attributable to CME Group (in millions) $ 513.8 $ 566.1 $ 1,010.7 $ 1,164.9 Weighted Average Number of Common Shares (in thousands): Basic 357,060 339,465 356,973 339,386 Effect of stock options, restricted stock and performance shares 1,095 1,407 1,130 1,452 Diluted 358,155 340,872 358,103 340,838 Earnings per Common Share Attributable to CME Group: Basic $ 1.44 $ 1.67 $ 2.83 $ 3.43 Diluted 1.43 1.66 2.82 3.42

Accounting Policies (Details)

Accounting Policies (Details) $ in Millions	Jun. 30, 2019USD ($)	Jan. 01, 2019USD ($)
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Lease Term Recognition-Balance Sheet	12
Finance Lease, Liability	$ 104.1	$ 568
Finance Lease, Right-of-Use Asset	$ 102.9	$ 448.2

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Revenue Recognition [Abstract]
Deferred Revenue	$ 57.9	$ 44.4

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total Revenues	$ 1,272.7	$ 1,059.6	$ 2,452.3	$ 2,168.6
Services transferred at a point in time [Member]
Revenues	988.1	890.6	1,881	1,848.4
Services transferred over time [Member]
Revenues	281.9	166.7	559.6	315.5
One-time charges and miscellaneous revenues [Member]
Revenues	2.7	2.3	11.7	4.7
Clearing and transaction fees [Member]
Revenues	1,051.8	906.1	2,004.4	1,879.7
Clearing and transaction fees [Member] | Interest rate [Member]
Revenues	347.4	288.9	650.2	627.3
Clearing and transaction fees [Member] | Equities [Member]
Revenues	148.1	157.3	294	352.3
Clearing and transaction fees [Member] | Foreign Exchange [Member]
Revenues	39.3	49.1	80.5	100.2
Clearing and transaction fees [Member] | Agricultural commodity [Member]
Revenues	141.5	141.4	246.5	262.5
Clearing and transaction fees [Member] | Energy [Member]
Revenues	179.3	192	344.3	383.6
Clearing and transaction fees [Member] | Metal [Member]
Revenues	58.1	60.5	109.1	119.9
Clearing and transaction fees [Member] | Cash Markets [Member]
Revenues	120.7	0	243.6	0
Clearing and transaction fees [Member] | Interest rate swap [Member]
Revenues	17.4	16.9	36.2	33.9
Market data and information services
Revenues	128.3	113.8	258.4	208.7
Other
Revenues	$ 92.6	$ 39.7	$ 189.5	$ 80.2

Performance Bonds and Guarant_2

Performance Bonds and Guaranty Fund Contributions (Details) $ in Billions	6 Months Ended
	Jun. 30, 2019USD ($)
Guarantor Obligations [Line Items]
Average Daily Clearing Settlement	$ 3.1
Federal Reserve Reinvestment [Member]
Guarantor Obligations [Line Items]
Cash Equivalents, at Carrying Value	$ 16.7

Intangible Assets And Goodwil_2

Intangible Assets And Goodwill (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of purchased intangibles	$ 76.1	$ 23.6	$ 156.8	$ 47.3

Intangible Assets And Goodwil_3

Intangible Assets And Goodwill (Components Of Intangible Assets) (Details) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Intangible Assets [Line Items]
Total intangible assets - other, net		$ 5,308.7	$ 5,500.1
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		5,828.1	5,862.5
Accumulated amortization		(1,206.2)	(1,065.6)
Net book value		4,621.9	4,796.9
Technology-Related Intellectual Property [Member]
Intangible Assets [Line Items]
Assigned Value		178.7	179.1
Accumulated amortization		(36.2)	(25.6)
Net book value		142.5	153.5
Other [Member]
Intangible Assets [Line Items]
Assigned Value		103.3	102.8
Accumulated amortization		(9)	(3.1)
Net book value		94.3	99.7
Total Amortizable Intangible Assets [Member]
Intangible Assets [Line Items]
Assigned Value		6,110.1	6,144.4
Accumulated amortization		(1,251.4)	(1,094.3)
Net book value		$ 4,858.7	$ 5,050.1
[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	Jun. 30, 2019USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2019	$ 157.8
2020	315.5
2021	315.4
2022	315
2023	313.6
2024	307
Thereafter	$ 3,134.4

Intangible Assets And Goodwil_5

Intangible Assets And Goodwill Goodwill (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 10,795.3	$ 10,805.3
CBOT [Member]
Goodwill [Line Items]
Goodwill	5,066.4	5,066.4	$ 5,066.4
Goodwill, Acquired During Period	0	0
Goodwill, Other Increase (Decrease)	0	0
NYMEX [Member]
Goodwill [Line Items]
Goodwill	2,462.2	2,462.2	2,462.2
Goodwill, Acquired During Period	0	0
Goodwill, Other Increase (Decrease)	0	0
NEX [Member]
Goodwill [Line Items]
Goodwill	3,226.3	3,236.3	0
Goodwill, Acquired During Period	0	3,236.3
Goodwill, Other Increase (Decrease)	(10)	0
Consolidated Entities [Member]
Goodwill [Line Items]
Goodwill	40.4	40.4	40.4
Goodwill, Acquired During Period	0	0
Goodwill, Other Increase (Decrease)	0	0
Goodwill [Member]
Goodwill [Line Items]
Goodwill	10,795.3	10,805.3	$ 7,569
Goodwill, Acquired During Period	0	3,236.3
Goodwill, Other Increase (Decrease)	$ (10)	$ 0

Debt Short Term Debt (Details)

Debt Short Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Short-term Debt	$ 0	$ 574.2
€350.0 million fixed rate notes due March 2019 [Member]
Short-term Debt [Line Items]
Short-term Debt	0	400.7
¥19.1 billion term loan due March 2019 [Member]
Short-term Debt [Line Items]
Short-term Debt	$ 0	$ 173.5

Debt (Schedule Of Short-Term An

Debt (Schedule Of Short-Term And Long-Term Debt) (Details) € in Millions, ¥ in Millions, $ in Millions	1 Months Ended			6 Months Ended
	Mar. 31, 2015	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2019USD ($)	Jun. 30, 2019EUR (€)	Jun. 30, 2019JPY (¥)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Long-term debt				$ 4,072.9			$ 3,826.8
Forward starting interest rate swap agreement fixed rate	3.11%	4.73%	3.32%
€350.0 million fixed rate notes due March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount | €					€ 350
Debt Instrument, Maturity Date				Mar. 31, 2019
Debt Instrument, Interest Rate, Stated Percentage				3.13%	3.13%	3.13%
¥19.1 billion term loan due March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount | ¥						¥ 19,100
Debt Instrument, Maturity Date				Mar. 31, 2019
Debt Instrument, Interest Rate, Stated Percentage				0.81%	0.81%	0.81%
$750.0 million Fixed Rate Notes Due September 2022, stated rate of 3.00% [Member]
Debt Instrument [Line Items]
Long-term debt				$ 747.3			746.9
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date				Sep. 15, 2022
Debt Instrument, Interest Rate, Stated Percentage				3.00%	3.00%	3.00%
€15.0 million fixed rate notes due May 2023 [Member]
Debt Instrument [Line Items]
Long-term debt				$ 16.6			16.6
Debt Instrument, Face Amount | €					€ 15
Debt Instrument, Maturity Date				May 1, 2023
Debt Instrument, Interest Rate, Stated Percentage				4.30%	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				$ 745.9			745.6
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date				Mar. 15, 2025
Debt Instrument, Interest Rate, Stated Percentage				3.00%	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				$ 496.1			495.9
Debt Instrument, Face Amount				$ 500
Debt Instrument, Maturity Date				Jun. 15, 2028
Debt Instrument, Interest Rate, Stated Percentage				3.75%	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				$ 742.6			742.4
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date				Sep. 15, 2043
Debt Instrument, Interest Rate, Stated Percentage				5.30%	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				$ 689.7			689.5
Debt Instrument, Face Amount				$ 700
Debt Instrument, Maturity Date				Jun. 15, 2048
Debt Instrument, Interest Rate, Stated Percentage				4.15%	4.15%	4.15%
Commercial Paper [Member]
Debt Instrument [Line Items]
Long-term debt				$ 634.7			$ 389.9

Debt (Schedule Of Maturities Of

Debt (Schedule Of Maturities Of Long-Term Debt) (Details) $ in Millions	Jun. 30, 2019USD ($)
Debt Disclosure [Abstract]
2020	$ 0
2021	0
2022	1,385
2023	17.1
2024	0
Thereafter	$ 2,700

Debt Narrative (details) (Detai

Debt Narrative (details) (Details) € in Millions, ¥ in Millions, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019EUR (€)	Jun. 30, 2019USD ($)	Jun. 30, 2019JPY (¥)
Short-term Debt [Line Items]
debt weighted average balance		$ 468.8
Weighted Average Discount Rate, Percent	2.40%		2.40%
€350.0 million fixed rate notes due March 2019 [Member]
Short-term Debt [Line Items]
Debt Instrument, Face Amount | €	€ 350
¥19.1 billion term loan due March 2019 [Member]
Short-term Debt [Line Items]
Debt Instrument, Face Amount | ¥			¥ 19,100
Commercial Paper [Member]
Short-term Debt [Line Items]
Proceeds from Issuance of Debt		$ 6,900
Minimum [Member]
Short-term Debt [Line Items]
commercial paper days outstanding	1
Maximum [Member]
Short-term Debt [Line Items]
commercial paper days outstanding	18

Leases (Details)

Leases (Details) $ in Millions	Jun. 30, 2019USD ($)	Jan. 01, 2019USD ($)
Leases [Abstract]
Finance Lease, Liability	$ 104.1	$ 568
Finance Lease, Right-of-Use Asset	$ 102.9	$ 448.2
Operating Lease, Weighted Average Remaining Lease Term	19
Lessee, Operating Lease, Renewal Term	5
Lessee, Operating Lease, Option to Terminate	12
Lessee, Operating Lease, Term of Contract	12
Lease Term Recognition-Balance Sheet	12

Leases Leases (Details)

Leases Leases (Details)	Jun. 30, 2019
Leases [Abstract]
Lease Term Recognition-Balance Sheet	12

Leases Lease Costs (Details)

Leases Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Operating Lease, Cost	$ 18.9	$ 37.3
Short-term Lease, Cost	1.5	4.9
Operating Lease, Expense	20.4	42.2
Finance Lease, Interest Expense	0.9	1.8
Finance Lease, Right-of-Use Asset, Amortization	2.4	4.6
Finance Lease, Expense	3.3	6.4
Sublease Income	$ 1.7	$ 5.3

Leases Supplemental Cash Flow I

Leases Supplemental Cash Flow Information-Leases (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Operating Lease, Payments	$ 16.9	$ 32.1
Finance Lease, Principal Payments	$ 4.8	$ 9

Leases Supplemental Balance She

Leases Supplemental Balance Sheet Information-Leases (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
Finance Lease, Right-of-Use Asset	$ 102.9	$ 448.2
Operating Lease, Right-of-Use Asset	433.5
Operating Lease, Liability, Current	41.3
Operating Lease, Liability, Noncurrent	524.3
Operating Lease, Liability	$ 565.6
Operating Lease, Weighted Average Remaining Lease Term	151 months
Operating Lease, Weighted Average Discount Rate, Percent	4.00%
Finance Lease, Liability, Current	$ 8.9
Finance Lease, Liability, Noncurrent	95.2
Finance Lease, Liability	$ 104.1	$ 568
Finance Lease, Weighted Average Remaining Lease Term	140 months
Finance Lease, Weighted Average Discount Rate, Percent	3.50%

Leases Operating Leases Future

Leases Operating Leases Future Minimum Payments (Details) $ in Millions	Jun. 30, 2019USD ($)
Operating Leases, Future Minimum Payments Due [Line Items]
Remainder of 2019	$ 31.5
2020	63.3
2021	60.1
2022	62.9
2023	59
2024	53.4
Thereafter	399
Total Operating Lease Payments	729.2
Operating Lease Payments, Less Imputed Interest	(163.6)
Present Value of Operating Lease Liability	$ 565.6

Leases Capital Leases, Future M

Leases Capital Leases, Future Minimum Payments Due (Details) $ in Millions	Jun. 30, 2019USD ($)
Capital Leases, Future Minimum Payments Due [Line Items]
Remainder of 2019	$ 9.9
2020	16.9
2021	17
2022	17.1
2023	17.2
2024	17.4
Thereafter	111.8
Total Capital Lease Payments	207.3
Capital Lease Payments, Less Imputed Interest	(103.2)
Present Value of Capital Lease Liability	$ 104.1

Guarantees (Details)

Guarantees (Details)	6 Months Ended
	Jun. 30, 2019USD ($)years
Guarantor Obligations [Line Items]
Agreement automatic renewal period (in years) | years	1
Contingent liability to SGX, amount of irrevocable letters of credit	$ 335,000,000
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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Balance		$ 22,772.8	$ 25,918.5	$ 22,411.8
Other comprehensive income (loss), net of tax	$ 4.8	(1.3)	0.3	0.5
Impact of adoption of standards update			(6.9)	8.7
Balance	26,455.2	23,123.6	26,455.2	23,123.6
Investment Securities [Member]
Balance			0.1	0.6
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)			1.7	(0.9)
Amounts reclassified from accumulated other comprehensive income (loss)			(0.1)	0
Income tax benefit (expense)			(0.4)	0.2
Other comprehensive income (loss), net of tax			1.2	(0.7)
Impact of adoption of standards update				0.1
Balance	1.3	0	1.3	0
Defined Benefit Plans [Member]
Balance			(53.8)	(36.1)
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)			(2.7)	1.7
Amounts reclassified from accumulated other comprehensive income (loss)			2.4	1.3
Income tax benefit (expense)			0.1	(0.8)
Other comprehensive income (loss), net of tax			(0.2)	2.2
Impact of adoption of standards update				(8.2)
Balance	(54)	(42.1)	(54)	(42.1)
Derivative Investments [Member]
Balance			69.7	58
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)			(0.2)	0
Amounts reclassified from accumulated other comprehensive income (loss)			(0.6)	(0.6)
Income tax benefit (expense)			0.1	0.2
Other comprehensive income (loss), net of tax			(0.7)	(0.4)
Impact of adoption of standards update				11.9
Balance	69	69.5	69	69.5
Foreign Currency Translation [Member]
Balance			(10.7)	(8.2)
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)			(3)	(0.6)
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Income tax benefit (expense)			3	0
Other comprehensive income (loss), net of tax			0	(0.6)
Impact of adoption of standards update				0
Balance	(10.7)	(8.8)	(10.7)	(8.8)
Accumulated Other Comprehensive Income (Loss) [Member]
Balance			5.3	14.3
Other comprehensive income (loss) before reclassifications and income tax benefit (expense)			(4.2)	0.2
Amounts reclassified from accumulated other comprehensive income (loss)			1.7	0.7
Income tax benefit (expense)			2.8	(0.4)
Other comprehensive income (loss), net of tax			0.3	0.5
Impact of adoption of standards update				3.8
Balance	$ 5.6	$ 18.6	$ 5.6	$ 18.6

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other than Temporary Impairment Losses, Investments	$ 18,700,000
Investment Owned, at Fair Value	0
Other Investments Owned, at Fair Value	900,000
Business Combination, Contingent Consideration, Liability	500,000		$ 6,700,000
Unrealized loss on assets held for sale	21,600,000	$ 0
Tangible Asset Impairment Charges	12,300,000
Assets Held-for-sale, Long Lived, Fair Value Disclosure	$ 3,600,000

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Business Combination, Contingent Consideration, Liability	$ 0.5	$ 6.7
Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	81.8
Total Assets at Fair Value	81.8
Derivative Contract Liability	2.4
Business Combination, Contingent Consideration, Liability	0.5
Total Liabilities at Fair Value	2.9
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	18.4
Fair Value, Measurements, Recurring [Member] | Mutual Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading Securities at Fair Value	63
Fair Value, Measurements, Recurring [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, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities at Fair Value	0.3
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	81.5
Total Assets at Fair Value	81.5
Derivative Contract Liability	0
Business Combination, Contingent Consideration, Liability	0
Total Liabilities at Fair Value	0
Fair Value, Measurements, Recurring [Member] | 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	18.4
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mutual Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading Securities at Fair Value	63
Fair Value, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	0.3
Total Assets at Fair Value	0.3
Derivative Contract Liability	2.4
Business Combination, Contingent Consideration, Liability	0
Total Liabilities at Fair Value	2.4
Fair Value, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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	0.3
Fair Value, Measurements, Recurring [Member] | 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
Derivative Contract Liability	0
Business Combination, Contingent Consideration, Liability	0.5
Total Liabilities at Fair Value	0.5
Fair Value, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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, Measurements, Recurring [Member] | 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 Measurements Reconci

Fair Value Measurements Reconciliation of Level 3 Liabilities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration, Liability	$ 0.5	$ 6.7
Unrealized losses included in other non-operating (income) expense	0.1
Goodwill, Purchase Accounting Adjustments	(6.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	$ (0.2)

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Values of Long-Term Debt) (Details) - 6 months ended Jun. 30, 2019 € 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	$ 769.7
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	$ 19.2
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	$ 780.2
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	$ 543.6
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	$ 960.4
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	$ 787.1
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	$ 634.7

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	55	7	55	9
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	55	7	55	9

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to CME Group	$ 513.8	$ 566.1	$ 1,010.7	$ 1,164.9
Basic (in shares)	357,060	339,465	356,973	339,386
Effect of stock options, restricted stock and performance shares	1,095	1,407	1,130	1,452
Diluted (in shares)	358,155	340,872	358,103	340,838
Earnings per common share, basic (in dollars per share)	$ 1.44	$ 1.67	$ 2.83	$ 3.43
Earnings per common share, diluted (in dollars per share)	$ 1.43	$ 1.66	$ 2.82	$ 3.42