CME (CME) 10-K 28 Feb 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2023	Feb. 07, 2024	Jun. 30, 2023
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
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, Address Line One	20 South Wacker Drive
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60606
City Area Code	312
Local Phone Number	930-1000
Title of 12(b) Security	Class A Common Stock $0.01 par value
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 66.3
Documents Incorporated by Reference	Documents Form 10-K Reference Portions of CME Group Inc.’s Proxy Statement for the 2024 Annual Meeting of Shareholders Part III
Entity Central Index Key	0001156375
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	CME
Amendment Flag	false
Document Financial Statement Error Correction [Flag]	false
Class A Common Stock (Shares) [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		359,991,858
Class B Common Stock, Class B1 [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		625
Class B Common Stock, Class B2 [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		813
Class B Common Stock, Class B3 [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		1,287
Class B Common Stock, Class B4 [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		413

Auditor Information

Auditor Information	12 Months Ended
	Dec. 31, 2023
Cover [Abstract]
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Chicago, Illinois

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Assets
Cash and cash equivalents		$ 2,912	$ 2,720.1
Marketable securities		111.7	96
Accounts receivable, net of allowance		535.6	483.2
Other current assets		1,138.4	529.8
Performance bonds and guaranty fund contributions		90,192.5	135,249.2
Total current assets		94,890.2	139,078.3
Property, net of accumulated depreciation and amortization		409.5	455.5
Intangible assets-trading products	[1]	17,175.3	17,175.3
Intangible assets—other, net		3,050.2	3,269.7
Goodwill		10,495.3	10,482.5
Other assets		3,685.6	3,714.4
Total Assets		129,706.1	174,175.7
Liabilities and Shareholders' Equity
Accounts payable		90.6	121.4
Short-term debt		0	16
Other current liabilities		3,133.8	2,300.9
Performance bonds and guaranty fund contributions		90,192.5	135,249.2
Total current liabilities		93,416.9	137,687.5
Long-term debt		3,425.4	3,422.4
Deferred Income Tax Liabilities, Net		5,327.7	5,361.1
Other liabilities		798.2	826
Total Liabilities		102,968.2	147,297
Shareholders' Equity:
Preferred stock, $0.01 par value, 10,000 shares authorized, none issued or outstanding		0	0
Additional paid-in capital		22,334.7	22,261.6
Retained earnings		4,455.2	4,746.8
Accumulated other comprehensive income (loss)		(55.6)	(133.3)
Total CME Group Shareholders' Equity		26,737.9	26,878.7
Total Liabilities and Shareholders' Equity		129,706.1	174,175.7
Class A Common Stock (Shares) [Member]
Shareholders' Equity:
Common stock		3.6	3.6
Class B Common Stock (Shares) [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 CFTC. Product authorizations from the CFTC have no term limits.

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Total Revenues	$ 5,578.9	$ 5,019.4	$ 4,689.7
Expenses
Compensation and benefits	828.6	753.1	837
Technology	218.7	188.6	192.6
Professional fees and outside services	144.4	137.4	151.7
Amortization of purchased intangibles	226.6	227.7	237.6
Depreciation and amortization	126	134.9	147.8
Licensing and other fee agreements	322.8	320	236.9
Other	276.1	241.8	240.9
Total Expenses	2,143.2	2,003.5	2,044.5
Operating Income	3,435.7	3,015.9	2,645.2
Non-Operating Income (Expense)
Investment income	5,275.3	2,198.4	306.9
Interest and other borrowing costs	(159.4)	(162.7)	(166.9)
Equity in net earnings (losses) of unconsolidated subsidiaries	296.9	301.1	245.8
Other income (expense)	(4,694.9)	(1,862.4)	342.6
Total Non-Operating	717.9	474.4	728.4
Income before Income Taxes	4,153.6	3,490.3	3,373.6
Income tax provision	927.4	799.3	736.7
Net income	3,226.2	2,691	2,636.9
Net Income (Loss) Attributable to Noncontrolling Interest	0	0	0.5
Net income attributable to CME Group	3,226.2	2,691	2,636.4
Net Income Attributable to Common Shareholders of CME Group	$ 3,185.6	$ 2,657.2	$ 2,617.1
Earnings per Common Share Attributable to CME Group:
Basic	$ 8.87	$ 7.41	$ 7.30
Diluted	$ 8.86	$ 7.40	$ 7.29
Weighted Average Number of Common Shares:
Basic	359,023	358,713	358,340
Diluted	359,500	359,181	358,929
Clearing and Transaction Fees [Member]
Revenues
Total Revenues	$ 4,588.5	$ 4,142.7	$ 3,765.1
MarketData [Member]
Revenues
Total Revenues	663.7	610.9	576.9
OtherRevenue [Member]
Revenues
Total Revenues	$ 326.7	$ 265.8	$ 347.7

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net income	$ 3,226.2	$ 2,691	$ 2,636.9
Net unrealized holding gains (losses) arising during the period	0.6	(2.7)	(1)
Reclassification of gains(loss) on sale included in investment income	0	0	0.3
Income tax benefit (expense)	(0.1)	0.7	0.2
Investment securities, net	0.5	(2)	(0.5)
Net change in defined benefit plans arising during the period	(0.9)	14.9	25.5
Amortization of net actuarial (gains) losses and prior service costs included in compensation and benefits expense	0.1	1.2	4.4
Income tax benefit (expense)	0.2	(4.1)	(7.6)
Defined benefit plans, net	(0.6)	12	22.3
Amortization of effective portion of net (gains) losses on cash flow hedges included in interest expense	(3.6)	(1.9)	(1.2)
Income tax benefit (expense)	0.9	0.5	0.3
Derivative investments, net	(2.7)	(1.4)	(0.9)
Foreign currency translation adjustments	70.8	(195.4)	(62)
Reclassification adjustment for (gain) loss included in other expense	9.7	0	(40.3)
Foreign currency translation, net	80.5	(195.4)	(102.3)
Other comprehensive income/(loss)	77.7	(186.8)	(81.4)
Comprehensive income	3,303.9	2,504.2	2,555.5
Less: comprehensive (income) loss attributable to non-controlling interest	0	0	(0.5)
Comprehensive income attributable to CME Group	$ 3,303.9	$ 2,504.2	$ 2,555

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands	Total	Common Stock and Additional Paid-in Capital [Member]	Parent [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	Series A junior participating preferred stock [Member]	Class A Common Stock (Shares) [Member]	Class B Common Stock (Shares) [Member]	Convertible Preferred Stock
Total CME Group Shareholders' Equity, beginning at Dec. 31, 2020		$ 21,189,100,000	$ 26,319,900,000	$ 4,995,900,000	$ 134,900,000
Noncontrolling Interest, beginning balance at Dec. 31, 2020						$ 31,600,000
Total Equity at Dec. 31, 2020	$ 26,351,500,000
Beginning Balance (in shares) at Dec. 31, 2020								358,110	3	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to CME Group	2,636,400,000		2,636,400,000	2,636,400,000
Net income (loss) attributable to non-controlling interests						500,000
Net income	2,636,900,000
Other comprehensive income/(loss)	(81,400,000)		(81,400,000)		(81,400,000)
Dividends, Cash	(2,480,400,000)		(2,480,400,000)	(2,480,400,000)
Sale of Stock, Consideration Received on Transaction		965,000,000
Impact of accounting standards update adoption	965,000,000		965,000,000
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests		(20,500,000)	(20,500,000)
Exercise of stock options (in shares)								101
Exercise of stock options	5,500,000	5,500,000	5,500,000
Vesting of issued restricted Class A common stock, shares								336
Vesting of issued restricted Class A common stock, value	(31,700,000)	(31,700,000)	(31,700,000)
Shares issued to Board of Directors (in shares)								14
Stock Issued to Board of Directors, Value, Issued for Services	2,900,000	2,900,000	2,900,000
Shares issued under Employee Stock Purchase Plan (in shares)								38
Shares issued under Employee Stock Purchase Plan	8,400,000	8,400,000	8,400,000
Stock-based compensation	75,200,000	75,200,000	75,200,000
Total CME Group Shareholders' Equity, ending at Dec. 31, 2021		22,193,900,000	27,399,300,000	5,151,900,000	53,500,000
Noncontrolling Interest, ending balance at Dec. 31, 2021						0
Total Equity at Dec. 31, 2021	27,399,300,000
Ending Balance (in shares) at Dec. 31, 2021								358,599	3	4,584
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Changes in non-controlling interest due to measurement period adjustments	(52,600,000)					$ (32,100,000)
Net income attributable to CME Group	2,691,000,000		2,691,000,000	2,691,000,000
Net income	2,691,000,000
Other comprehensive income/(loss)	(186,800,000)		(186,800,000)		(186,800,000)
Dividends, Cash			(3,096,100,000)	(3,096,100,000)
Exercise of stock options (in shares)								1
Exercise of stock options		100,000	100,000
Vesting of issued restricted Class A common stock, shares								269
Vesting of issued restricted Class A common stock, value		(24,800,000)	(24,800,000)
Shares issued to Board of Directors (in shares)								19
Stock Issued to Board of Directors, Value, Issued for Services		4,000,000	4,000,000
Shares issued under Employee Stock Purchase Plan (in shares)								41
Shares issued under Employee Stock Purchase Plan		7,700,000	7,700,000
Stock-based compensation		84,300,000	84,300,000
Total CME Group Shareholders' Equity, ending at Dec. 31, 2022	26,878,700,000	22,265,200,000	26,878,700,000	4,746,800,000	(133,300,000)
Ending Balance (in shares) at Dec. 31, 2022								358,929	3	4,584
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock, Shares Issued							4,584
Net income attributable to CME Group	3,226,200,000		3,226,200,000	3,226,200,000
Net income	3,226,200,000
Other comprehensive income/(loss)	77,700,000		77,700,000		77,700,000
Dividends, Cash			(3,517,800,000)	(3,517,800,000)
Vesting of issued restricted Class A common stock, shares								241
Vesting of issued restricted Class A common stock, value		(21,400,000)	(21,400,000)
Shares issued to Board of Directors (in shares)								20
Stock Issued to Board of Directors, Value, Issued for Services		3,600,000	3,600,000
Shares issued under Employee Stock Purchase Plan (in shares)								41
Shares issued under Employee Stock Purchase Plan		8,000,000	8,000,000
Stock-based compensation		82,900,000	82,900,000
Total CME Group Shareholders' Equity, ending at Dec. 31, 2023	$ 26,737,900,000	$ 22,338,300,000	$ 26,737,900,000	$ 4,455,200,000	$ (55,600,000)
Ending Balance (in shares) at Dec. 31, 2023								359,231	3	4,584
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock, Shares Issued	4,600						4,584

CONSOLIDATED STATEMENTS OF SH_2

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY Equity Statement Parentheticals - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Stockholders' Equity Parentheticals [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 8.50	$ 6.85	$ 5.90
Preferred Stock, Dividends Per Share, Declared	$ 8.50	$ 4.15	$ 0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities
Net income	$ 3,226.2	$ 2,691	$ 2,636.9
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	82.9	84.3	75.2
Amortization of purchased intangibles	226.6	227.7	237.6
Depreciation and amortization	126	134.9	147.8
Gain on sale of building	0	0	30.4
Gain on joint venture	0	0	400.7
Net realized and unrealized (gains)/losses on investments	(72.1)	(4.8)	(117)
Deferred income taxes	(75)	(23.2)	34.8
Change in assets and liabilities:
Accounts receivable	(51.5)	(51.1)	(45.7)
Other current assets	(637.8)	(76.5)	(55.4)
Other assets	92	87	61.3
Accounts payable	(30.8)	72.5	(18.6)
Income tax payable	(77.1)	(147.8)	(120.5)
Other current liabilities	642.7	88.1	61.9
Other liabilities	(32.7)	(67.4)	(44.8)
Other	34.4	41.3	(20)
Net Cash Provided by Operating Activities	3,453.8	3,056	2,402.4
Cash Flows from Investing Activities
Proceeds from maturities and sales of available-for-sale marketable securities	5.9	6.3	9.4
Purchases of available-for-sale marketable securities	4.1	4.4	7.8
Purchases of property, net	(76.4)	(89.7)	(127.2)
Investments in business ventures	2.4	3.1	4.5
Proceeds from sale of business ventures	97.9	11.1	101.4
Payment for acquisition of subsidiary's interests from the non-controlling interest	0	0	52.9
Proceeds from the sale of building property	0	0	39.3
Net cash proceeds from OSTTRA joint venture transaction	0	0	100.7
Investment in S&P Dow Jones Indices LLC	0	410	0
Net Cash Used in Investing Activities	20.9	(489.8)	58.4
Cash Flows from Financing Activities
Proceeds from debt, net of issuance costs	0	741	0
Repayment of other borrowings, including call premiums	(16.4)	(756.2)	0
Proceeds from preferred stock offering	0	0	965
Cash dividends	(3,235.5)	(2,633.5)	(2,189.3)
Change in performance bond and guaranty fund contributions	(45,056.7)	(22,700.3)	71,167.8
Employee taxes paid on restricted stock vesting	(21.4)	(24.8)	(31.7)
Other	(9.3)	(7.9)	(3.1)
Net Cash Provided by (Used in) Financing Activities	(48,339.3)	(25,381.7)	69,908.7
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(44,864.6)	(22,815.5)	72,369.5
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning Balance	137,974.3	160,789.8	88,420.3
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	93,109.7	137,974.3	160,789.8
Supplemental Disclosure of Cash Flow Information
Cash and cash equivalents	2,912	2,720.1	2,834.9
Short-term restricted cash (within other current assets)	5.2	4.9	4.8
Long-term restricted cash (within other assets)	0	0.1	0.5
Restricted cash and restricted cash equivalents (performance bonds and guaranty fund contributions)	90,192.5	135,249.2	157,949.6
Income taxes paid	1,109.4	973.4	755
Interest paid	129.9	133.2	133.3
Dividends declared	$ 1,910	$ 1,635.7	$ 1,183.8

CONSOLIDATED BALANCE SHEETS Par

CONSOLIDATED BALANCE SHEETS Parentheticals - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Condensed Balance Sheet Statements, Captions [Line Items]
Allowance for Doubtful Accounts Receivable	$ 7.1	$ 8.1
Short-term restricted cash (within other current assets)	5.2	4.9
Long-term restricted cash (within other assets)	$ 0	$ 0.1
Preferred Stock, Shares Issued	4,600,000
Series A junior participating preferred stock [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	4,584,000	4,584,000
Preferred Stock, Shares Outstanding	4,584,000	4,584,000
Series B Preferred Stock [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Stock, Par or Stated Value Per Share	$ 0	$ 0
Preferred Stock, Shares Authorized	0	0
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Class A Common Stock (Shares) [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	359,231,000	358,929,000
Common Stock, Shares, Outstanding	359,231,000	358,929,000
Class B Common Stock (Shares) [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	3,000	3,000
Common Stock, Shares, Issued	3,000	3,000
Common Stock, Shares, Outstanding	3,000	3,000

Organization and Business

Organization and Business	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Business	ORGANIZATION AND BUSINESS CME Group Inc. (CME Group) exchanges offer the widest range of global benchmark products across all major asset classes based on interest rates, equity indexes, foreign exchange (FX), agricultural, energy and metal commodities. We offer futures and options across asset classes as well as cash, repo fixed income and OTC FX trading through the CME Globex platform. In addition, it operates one of the world’s leading central counterparty clearing houses. CME Group offers clearing, settlement and guarantees for all products cleared through the clearing house. Chicago Mercantile Exchange Inc. (CME), the Board of Trade of the City of Chicago, Inc. (CBOT), New York Mercantile Exchange, Inc. (NYMEX) and Commodity Exchange, Inc. (COMEX), wholly-owned subsidiaries of CME Group, are designated contract markets for the trading of futures and options contracts. In September 2021, the company and IHS Markit launched a new joint venture, OSTTRA, to combine their post-trade services. OSTTRA performs trade processing and risk mitigation services. The company contributed the net assets of its optimization business, which included Traiana, TriOptima and Reset, to the joint venture and deconsolidated the net assets of the optimization business. The financial statements and accompanying notes presented in this report exclude the assets, liabilities, revenues and expenses from the optimization business and include an investment in the joint venture and equity in net earnings from the joint venture after September 2021.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation. The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the U.S. and include the accounts of the company and its subsidiaries. All intercompany transactions and balances have been eliminated. Use of Estimates. The preparation of consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts and the disclosure of contingent amounts on the consolidated financial statements and accompanying notes. Estimates are based on historical experience, where applicable, and assumptions management believes are reasonable under the circumstances. Due to the inherent uncertainty involved with estimates, actual results may differ. Cash and Cash Equivalents. Cash and cash equivalents consist of cash and highly liquid investments with a maturity of three months or less at the time of purchase. Financial Investments. The company maintains short-term and long-term investments, classified as equity method investments, available-for-sale debt securities, equity investments in privately-held entities and trading securities. Available-for-sale debt securities are carried at fair value, with unrealized gains and losses, net of deferred income taxes, reported as a component of accumulated other comprehensive income. Trading securities held in connection with non-qualified deferred compensation plans are recorded at fair value, with net realized and unrealized gains and losses and dividend income reported as investment income. For equity investments in privately-held entities that do not have a readily determinable fair value, our accounting policy is to utilize the measurement alternative for valuation of these investments, which permits the company to estimate fair value at cost minus impairment, plus or minus changes resulting from observable price movements. Additionally, the company maintains long-term investments accounted for under the equity method, which requires that the company recognize its share of net income (loss) and other comprehensive income (loss) in the investee as an adjustment to the carrying amount of the investment each reporting period. The company reviews its investment portfolio at least quarterly, as well as whenever facts or circumstances exist which indicate that the carrying value of an investment is greater than its fair value. For investments not carried at fair value, the carrying value of the investment is reduced to its fair value and a corresponding impairment expense is charged to earnings, if events and circumstances indicate that a markdown to fair value is warranted. Declines in the fair value of available-for-sale debt securities that are deemed to represent indicators of impairment are charged to earnings as a realized loss. Fair Value of Financial Instruments. The company uses a three-level classification hierarchy of fair value measurements that establishes the quality of inputs used to measure fair value. The fair value of a financial instrument is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value of financial instruments is determined using various techniques that involve some level of estimation and judgment, the degree of which is dependent on the price transparency and the complexity of the instruments. Derivative Investments. The company occasionally uses derivative instruments to limit exposure to changes in interest rates and foreign currency exchange rates. Derivatives are recorded at fair value on the consolidated balance sheets. For those derivatives that meet the criteria for hedge accounting and are classified as effective cash flow hedges, changes in the fair value of derivative financial instruments are initially recorded in other comprehensive income and subsequently reclassified into earnings when the hedged item affects income. The company assesses, both at the inception of each hedge and on an ongoing basis, whether the derivative financial instruments that are designated as cash flow hedging transactions are highly effective in offsetting changes in cash flows of the hedged items. For any hedges no longer deemed effective or for which hedge accounting is not applied, changes in fair value of the derivative instruments are recognized in earnings within other non-operating income (expense). There were no outstanding derivative instruments at December 31, 2023. Accounts Receivable. Accounts receivable are comprised of trade receivables and unbilled revenue. All accounts receivable are stated at net realizable value. Exposure to losses on receivables for clearing and transaction fees and other amounts owed by clearing and trading firms is dependent on each firm's financial condition. With respect to clearing firms, our credit loss exposure is mitigated by the memberships that collateralize fees owed to the company. The company retains the right to liquidate exchange memberships to satisfy an outstanding receivable. The allowance for doubtful accounts is calculated based on management's assessment of future expected losses over the life of the receivable, historical trends and the current economic environment within which we operate. Performance Bonds and Guaranty Fund Contributions. Performance bonds and guaranty fund contributions held for clearing firms may be in the form of cash, securities or other non-cash deposits. Performance bonds and guaranty fund contributions received in the form of cash held by CME may be invested in U.S. government securities, U.S. government agency securities and certain foreign government securities acquired through and held by a bank or broker-dealer subsidiary of a bank, a cash account at the Federal Reserve Bank of Chicago, investments in highly rated government securities, money market funds or through CME's Interest Earning Facility (IEF) program. Any interest earned on these investments accrues to CME and is included in investment income on the consolidated statements of income. CME may distribute any interest earned on its investments to the clearing firms at its discretion. Because CME has control of the cash collateral and the benefits and market risks of ownership accrue to CME, cash performance bonds and guaranty fund contributions are reflected on the consolidated balance sheets. The cash performance bonds and guaranty fund contributions are considered restricted cash as the cash deposits cannot be used for the company's operations or to satisfy any operational liabilities. Securities and other non-cash deposits may include U.S. Treasury securities, U.S. government agency securities, Eurobonds, corporate bonds, other foreign government securities and gold bullion. Securities and other non-cash deposits are held in safekeeping by a custodian bank. Interest and gains or losses on securities deposited to satisfy performance bond and guaranty fund requirements accrue to the clearing firm. Because the benefits and risks of ownership accrue to the clearing firm, non-cash performance bonds and guaranty fund contributions are not reflected on the consolidated balance sheets. Property. Property is stated at cost, less accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method, generally over two to nineteen years. Property and equipment are depreciated over their estimated useful lives. Leasehold improvements are amortized over the shorter of the remaining term of the respective lease to which they relate or the remaining useful life of the leasehold improvement. Land is reported at cost. Internal and external costs incurred in developing, obtaining, or implementing computer software for internal use which meet the requirements for capitalization are amortized on a straight-line basis over the estimated useful life of the software, generally two to four years, but up to eight years for certain trading and clearing applications, depending upon expected useful lives. Leases. The company accounts for our leases of office space as operating leases. Landlord allowances are recorded as a direct reduction to the capitalized lease asset, which is reported in other assets and amortized to rent expense over the term of the lease. Both lease and direct non-lease costs are accounted for as a single lease component for purposes of capitalization on the consolidated balance sheets.The associated lease liability represents the present value of lease payments remaining in the lease term and is recorded within current and other liabilities depending upon the balance sheet classification of the payment obligations as short-term or long-term. For sale leaseback transactions, the company evaluates the sale and the lease arrangement based on the company's conclusion as to whether control of the underlying asset has been transferred and recognizes the sale leaseback as either a sale transaction or under the financing method, which requires the asset to remain on the consolidated balance sheets throughout the term of the lease and the proceeds to be recognized as a financing obligation. A portion of the lease payments is recognized as a reduction of the financing obligation and a portion is recognized as interest expense based on an imputed interest rate. Goodwill and Other Intangible Assets. Goodwill represents the excess of the purchase price over the fair value of the net assets acquired in a business combination. The company reviews goodwill for impairment at least quarterly and whenever events or circumstances indicate that the carrying value may not be recoverable. The company may test goodwill quantitatively for impairment by comparing the carrying value of a reporting unit to its estimated fair value. Estimating the fair value of a reporting unit involves significant judgments inherent in the analysis, including estimating the amount and timing of future cash flows and the selection of appropriate discount rates and long-term growth rate assumptions. Changes in these estimates and assumptions could materially affect the determination of fair value for the reporting unit. If the carrying amount exceeds fair value, an impairment loss is recorded. In certain circumstances, goodwill may be reviewed qualitatively for indications of impairment without utilizing valuation techniques to estimate fair value. The company performs an impairment assessment of indefinite-lived intangible assets at least quarterly or whenever events or circumstances indicate that their carrying values may not be recoverable. If the indefinite-lived intangible asset carrying value exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. Estimating the fair value of indefinite-lived intangible assets involves the use of valuation techniques that rely on significant estimates and assumptions, including forecasted revenue growth rates, forecasted allocations of expense and risk-adjusted discount rates. Changes in these estimates and assumptions could materially affect the determination of fair value for indefinite-lived intangible assets. In certain circumstances, indefinite-lived intangible assets may be reviewed qualitatively for indications of impairment without utilizing valuation techniques to estimate fair value. Intangible assets subject to amortization are also assessed for impairment at least quarterly or when indicated by a change in economic or operational circumstances. The impairment assessment of these assets requires management to first compare the carrying value of the amortizing asset to undiscounted net cash flows. If the carrying value exceeds the undiscounted net cash flows, management is then required to estimate the fair value of the assets and record an impairment loss for the excess of the carrying value over the fair value. In connection with this impairment assessment, management also challenges the useful lives of our amortizing intangible assets. Business Combinations. The company accounts for business combinations using the acquisition method. The method requires the acquirer to recognize the assets acquired, liabilities assumed, and any non-controlling interest in the acquiree at the acquisition date, measured at their fair values as of that date. The company may use independent valuation services to assist in determining the estimated fair values. Employee Benefit Plans. The company recognizes the funded status of defined benefit postretirement plans on its consolidated balance sheets. Changes in that funded status are recognized in the year of change in other comprehensive income (loss). Plan assets and obligations are measured at year end. The company recognizes future changes in actuarial gains and losses and prior service costs in the year in which the changes occur through accumulated other comprehensive income (loss). Foreign Currency Translation and Re-measurement . Foreign currency denominated monetary assets and liabilities are re-measured into the functional currency using period-end exchange rates. Gains and losses from foreign currency transactions and re-measurement of monetary assets and liabilities into the functional currency are included in other expense on the accompanying consolidated statements of income. When the functional currency differs from the reporting currency, revenues and expenses of foreign subsidiaries are translated from their functional currencies into U.S. dollars using weighted-average exchange rates while their assets and liabilities are translated into U.S. dollars using period-end exchange rates. Gains and losses resulting from foreign currency translations are included in accumulated other comprehensive income (loss) within shareholders' equity. Revenue Recognition. Revenue recognition policies for specific sources of revenue are discussed below. Clearing and Transaction Fees. Clearing and transaction fees include per-contract charges for trade execution, clearing, trading on the company's electronic trading platforms, portfolio reconciliation and compression services, risk mitigation, and other fees. Fees are charged at various rates based on the product traded, the method of trade, the exchange trading privileges of the customer making the trade and the type of contract. The majority of our clearing and transaction fees are recognized as revenue upon successful execution of the trade. Therefore, unfilled or canceled buy and sell orders have no impact on revenue. On occasion, the customer's exchange trading privileges may not be properly entered by the clearing firm and incorrect fees are charged for the transactions. When this information is corrected within the time period allowed by the company, a fee adjustment is provided to the clearing firm. A reserve is established for estimated fee adjustments to reflect corrections to customer exchange trading privileges. The reserve is based on the historical pattern of adjustments processed as well as management's estimate of future adjustment activity. The company believes the reserve is adequate to cover estimated adjustments as of December 31, 2023 and 2022. Market Data and Information Services. Market data and information services represent revenue earned for the dissemination of market information. Revenues are accrued each month based on the number of devices reported by vendors or over a straight line basis in accordance with the market data subscription contract term. The company conducts periodic examinations of the number of devices reported and assesses additional fees as necessary. On occasion, customers will pay for services in a lump sum payment; however, revenue is recognized as services are provided. Other Revenues. Other revenues include access and communication fees, fees for collateral management, equity membership subscription fees and fees for trade order routing through agreements from various strategic relationships as well as other services to customers. Revenue is recognized as services are provided. Concentration of Revenue. No clearing firms represented at least approximately 10% of the company's clearing and transaction fee revenue in 2023. One clearing firm represented at least approximately 10% of the company's clearing and transaction fee revenue in 2022 and 2021. Should a clearing firm withdraw from the company, management believes that the customer portion of that firm's trading activity would likely transfer to another clearing firm. Therefore, management does not believe that the company is exposed to significant risk from the ongoing loss of revenue received from a particular clearing firm. The two largest resellers of market data represented approximately 32% of market data and information services revenue in 2023, 33% in 2022, and 34% in 2021. Should one of these vendors no longer subscribe to the company's market data, management believes that the majority of that firm's customers would likely subscribe to the market data through another reseller. Therefore, management does not believe that the company is exposed to significant risk from a loss of revenue received from any particular market data reseller. Share-Based Payments. The company accounts for share-based payments at fair value, which is based on the grant date price of the equity awards issued. The company recognizes expense relating to stock-based compensation on an accelerated basis. As a result, the expense associated with each vesting date within a stock grant is recognized over the period of time that each portion of that grant vests. Forfeitures are recognized in the period in which they occur. Marketing Costs. Marketing costs are incurred for the production and communication of advertising as well as other marketing activities. These costs are expensed when incurred, except for costs related to the production of broadcast advertising, which are expensed when the first broadcast occurs. Income Taxes. Deferred income taxes arise from temporary differences between the tax basis and book basis of assets and liabilities. A valuation allowance is recognized if it is anticipated that some or all of a deferred tax asset may not be realized. The company accounts for uncertainty in income taxes recognized in its consolidated financial statements by using a more-likely-than-not recognition threshold based on the technical merits of the tax position taken or expected to be taken. The company recognizes interest and penalties related to uncertain tax positions in income tax expense. Segment Reporting. The company reports the results of its operations as one operating segment primarily comprised of the businesses of CME, CBOT, NYMEX, COMEX and our cash markets business. The individual operations of the company do not meet the thresholds for reporting separate segment information. Recent Accounting Pronouncements. The following accounting pronouncements were issued during 2023: In November 2023, the FASB issued an accounting update that requires public entities to provide in interim periods all disclosures about a reportable segment's profit or loss and assets that are currently required annually. Entities are permitted to disclose more than one measure of a segment's profit or loss if such measures are used by the chief operating decision-maker to allocate resources and assess performance, as long as at least one of those measures is determined in a way that is most consistent with the measurement principles used to measure the corresponding amounts in the consolidated financial statements. The guidance is effective beginning with our annual report on Form 10-K for the fiscal year ended December 31, 2024 and for interim periods thereafter. The disclosures must be applied retrospectively to all periods presented in the financial statements and early adoption is permitted. The company does not believe that adoption of this guidance will have a material impact on the consolidated financial statements. In December 2023, the FASB issued an accounting update that requires public business entities to disclose in their rate reconciliation table additional categories of information about federal, state and foreign income taxes and to provide more details about the reconciling items in certain categories if they meet a quantitative threshold. It is also noted that this guidance requires all entities to disclose annually income taxes paid (net of refunds received) disaggregated by federal, state and foreign taxes and to disaggregate the information by jurisdiction based on a quantitative threshold. The guidance is effective for annual periods beginning in 2025 and may be applied prospectively or retrospectively. The company is in the process of evaluating the impact of this update on our consolidated financial statements.

Revenue Recognition Revenue Rec

Revenue Recognition Revenue Recognition (Notes)	12 Months Ended
	Dec. 31, 2023
Revenue Recognition and Deferred Revenue [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUE RECOGNITION The company generates revenue from customers from the following sources: Clearing and transaction fees. Clearing and transaction fees include electronic trading fees and brokerage commissions, surcharges for privately-negotiated transactions, portfolio reconciliation and compression services, risk mitigation and other volume-related charges for trade contracts. Clearing and transaction fees are assessed upfront at the time of trade execution. As such, the company recognizes the majority of the fee revenue upon successful execution of the trade. The minimal remaining portion of the fee revenue related to settlement activities performed after trade execution is recognized over the short-term period that the contract is outstanding, based on management’s estimates of the average contract lifecycle. These estimates are based on various assumptions to approximate the amount of fee revenue to be attributed to services performed through contract settlement, expiration, or termination. For cleared trades, these assumptions include the average number of days that a contract remains in open interest, contract turnover, average revenue per day, and revenue remaining in open interest at the end of each period. The nature of contracts gives rise to several types of variable consideration, including volume-based pricing tiers, customer incentives associated with market maker programs and other fee discounts. The company includes fee discounts and incentives in the estimated transaction price when there is a basis to reasonably estimate the amount of the fee reduction. These estimates are based on historical experience, anticipated performance, and best judgment at the time. Because of the company's certainty in estimating these amounts, they are included in the transaction price of contracts. Market data and information services. Market data and information services represent revenue from the dissemination of market data to subscribers, distributors, and other third-party licensees of market data. Pricing for market data is primarily based on the number of reportable devices used as well as the number of subscribers enrolled under the arrangement. Fees for these services are generally billed monthly. Market data services are satisfied over time and revenue is recognized on a monthly basis as the customers receive and consume the benefit of the market data services. However, the company also maintains certain annual license arrangements with one-time upfront fees. The fees for annual licenses are initially recorded as a contract liability and recognized as revenue monthly over the term of the annual period. Other. Other revenues include certain access and communication fees, fees for collateral management, equity membership subscription fees, and fees for trade order routing through agreements from various strategic relationships. Access and communication fees are charged to customers that utilize various telecommunications networks and communications services. Fees for these services are generally billed monthly and the associated fee revenue is recognized as billed. Collateral management fees are charged to clearing firms that have collateral on deposit with the clearing house to meet their minimum performance bond and guaranty fund obligations on the exchange. These fees are calculated based on daily collateral balances and are billed monthly. This fee revenue is recognized monthly as billed as the customers receive and consume the benefits of the services. The company also has an equity membership program which provides equity members the option to substitute a monthly subscription fee for their existing requirement to hold CME Group Class A common stock. Choosing to pay this fee in lieu of holding Class A shares is entirely voluntary and the client's choice. Fee revenue under this program is earned monthly as billed over the contractual term. 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 years ended December 31, 2023, 2022 and 2021: (in millions) 2023 2022 2021 Interest rates $ 1,558.4 $ 1,326.8 $ 1,121.9 Equity indexes 1,036.4 1,016.3 752.1 Foreign exchange 190.0 188.3 159.2 Agricultural commodities 508.5 444.7 457.8 Energy 702.8 585.5 616.5 Metals 224.7 196.9 198.8 BrokerTec fixed income 152.1 164.7 172.0 EBS foreign exchange 132.6 154.1 164.3 Interest Rate Swap 83.0 65.4 62.6 Optimization — — 59.9 Total clearing and transaction fees 4,588.5 4,142.7 3,765.1 Market data 663.7 610.9 576.9 Other 326.7 265.8 347.7 Total revenues $ 5,578.9 $ 5,019.4 $ 4,689.7 Timing of Revenue Recognition Services transferred at a point in time 4,491.1 4,044.3 3,656.6 Services transferred over time 1,069.7 955.3 1,021.5 One-time charges and miscellaneous revenues 18.1 19.8 11.6 Total revenues $ 5,578.9 $ 5,019.4 $ 4,689.7 The timing of revenue recognition, billings and cash collections results in billed accounts receivable, and customer advances and deposits (contract liabilities) on the consolidated balance sheets. Certain fees for transactions, annual licenses, and other revenue arrangements are billed upfront before revenue is recognized, which results in the recognition of contract liabilities. These liabilities are recognized on the consolidated balance sheets on a contract-by-contract basis upon commencement of services under the customer contract. These upfront customer payments are recognized as revenue over time as the obligations under the contracts are satisfied. Changes in the contract liability balances during 2023 were not materially impacted by any other factors. The balance of contract liabilities was $13.2 million and $12.7 million as of December 31, 2023 and 2022, respectively.

Performance Bonds and Guaranty

Performance Bonds and Guaranty Fund Contributions	12 Months Ended
	Dec. 31, 2023
Performance Bonds and Guaranty Fund Contributions [Abstract]
Performance Bonds and Guaranty Fund Contributions	PERFORMANCE BONDS AND GUARANTY FUND CONTRIBUTIONS The clearing house clears and guarantees the settlement of contracts traded in the futures and options and interest rate swap markets. In its guarantor role, the clearing house has precisely equal and offsetting claims to and from clearing firms on opposite sides of each contract, standing as an intermediary on every contract cleared. In the U.S., clearing firm funds are held according to Commodity and Futures Trading Commission (CFTC) regulatory account segregation standards. To the extent that funds are not otherwise available to satisfy an obligation under the applicable contract, the clearing house bears counterparty credit risk in the event that future market movements create conditions that could lead to clearing firms failing to meet their obligations to the clearing house. The clearing house reduces the exposure through risk management programs that include initial and ongoing financial standards for designation as a clearing firm, performance bond requirements, daily mark-to-market, mandatory guaranty fund contributions and intra-day monitoring. Each clearing firm is required to deposit and maintain balances in the form of cash, U.S. government securities, certain foreign government securities, bank letters of credit or other approved collateral to satisfy performance bond and guaranty fund requirements. All non-cash deposits and certain cash deposits with foreign currency exposure are marked-to-market and haircut on a daily basis. Securities deposited by the clearing firms are not reflected on the consolidated financial statements and the clearing house does not earn any interest on these deposits. These balances may fluctuate significantly over time due to investment choices available to clearing firms and changes in the amount of contributions required. The clearing house marks-to-market open positions at least once a day (twice a day for futures and options contracts), and requires payment from clearing firms whose positions have lost value and makes payments to clearing firms whose positions have gained value. The clearing house has the capability to mark-to-market more frequently as market conditions warrant. Under the extremely unlikely scenario of simultaneous default by every clearing firm who has open positions with unrealized losses, the maximum exposure at the time of default related to positions other than 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 cleared interest rate swap contracts, the maximum exposure at the time of default related to the clearing house's guarantee would be one full day of changes in fair value of all open positions, before considering the clearing house's ability to access defaulting clearing firms' collateral. During 2023, the clearing house transferred an average of approximately $5.9 billion a day through the clearing system for settlement from clearing firms whose positions had lost value to clearing firms whose positions had gained value. The clearing house reduces its exposure through maintenance performance bond requirements and guaranty fund contributions. For futures and options products, the clearing firms' collateral requirements are sized to cover at least one day of anticipated price movements. For cleared swap products, the clearing firms' collateral requirements are sized to cover at least five days of anticipated price movements. Management has assessed the fair value of the company's settlement guarantee liability by taking the following factors into consideration: the design and operations of the clearing risk management process, the financial safeguard packages in place, historical evidence of default by a clearing member and the estimated probability of potential payouts by the clearing house. Based on the assessment performed, management estimates the guarantee liability to be nominal and therefore has not recorded any liability at December 31, 2023. CME has been designated as a systemically important financial market utility by the Financial Stability Oversight Council and is authorized to maintain cash accounts at the Federal Reserve Bank of Chicago. At December 31, 2023 and 2022, the clearing house maintained $79.3 billion and $124.9 billion, respectively, within the cash accounts at the Federal Reserve Bank of Chicago. The cash deposited at the Federal Reserve Bank of Chicago is included within performance bonds and guaranty fund contributions on the consolidated balance sheets. CME and The Options Clearing Corporation (OCC) have a perpetual cross-margin arrangement, whereby a clearing firm may maintain a cross-margin account in which a clearing firm's positions in certain equity index futures and options are combined with certain positions cleared by OCC for purposes of calculating performance bond requirements. The performance bond deposits are held jointly by CME and OCC. Cross-margin cash, securities and letters of credit jointly held with OCC under the cross-margin agreement are reflected at 50% of the total, or CME's proportionate share per that agreement. If a participating firm defaults, the gain or loss on the liquidation of the firm's open position and the proceeds from the liquidation of the cross margin account would be allocated equally between CME and OCC. In the event of a remaining loss, CME would first apply assets of the defaulting clearing firm to satisfy its payment obligation. These assets include the defaulting firm's guaranty fund contributions, performance bonds and any other available assets, such as assets required for clearing membership and any associated trading rights. Thereafter, if the payment default remains unsatisfied, the clearing house would use its corporate contributions designated for the respective financial safeguard package. The clearing house would then use guaranty fund contributions of other clearing firms within the respective financial safeguard package and funds collected through an assessment against solvent clearing firms within the respective financial safeguard package to satisfy the deficit. In addition, CME has a cross-margin arrangement with Fixed Income Clearing Corporation (FICC) whereby certain of the clearing firms' offsetting positions with CME and FICC are subject to reduced performance bond requirements. Clearing firms maintain separate performance bond deposits with each clearing house, but based on the net offsetting positions between CME and FICC, each clearing house may reduce that firm's performance bond requirements. If a participating firm defaults, the gain or loss on the liquidation of the firm’s open positions and the proceeds from the liquidation of the cross margin account would be allocated between CME and FICC pursuant to a publicly-available cross-margining agreement. In the event of a remaining loss, CME would first apply assets of the defaulting clearing firm to satisfy its payment obligation. These assets include the defaulting firm's guaranty fund contributions, performance bonds and any other available assets, such as assets required for clearing membership and any associated trading rights. Thereafter, if the payment default remains unsatisfied, the clearing house would use its corporate contributions designated for the respective financial safeguard package. The clearing house would then use guaranty fund contributions of other clearing firms within the respective financial safeguard package and funds collected through an assessment against solvent clearing firms within the respective financial safeguard package to satisfy the deficit. Each clearing firm for futures and options is required to deposit and maintain specified guaranty fund contributions in the form of cash or U.S. Treasury securities (base guaranty fund). In the event that performance bonds, guaranty fund contributions and other assets required to support clearing membership of a defaulting clearing firm are inadequate to fulfill that clearing firm's outstanding financial obligation, the base guaranty fund for contracts other than interest rate swaps is available to cover potential losses after first utilizing $100.0 million of corporate contributions designated by CME to be used in the event of a default of a clearing firm for the base guaranty fund. The clearing house maintains a separate guaranty fund to support the clearing firms that clear interest rate swap products (cleared interest rate swaps contract guaranty fund). The funds for interest rate swaps are independent of the base guaranty fund and are isolated to clearing firms for products in the respective asset class. Each clearing firm for cleared interest rate swaps is required to deposit and maintain specified guaranty fund contributions in the form of cash or U.S. Treasury securities. In the event that performance bonds, guaranty fund contributions and other assets required to support clearing membership of a defaulting clearing firm for cleared interest rate swap contracts are inadequate to fulfill that clearing firm's outstanding financial obligation, the interest rate swaps contracts guaranty fund is available to cover potential losses after first utilizing $150.0 million of corporate contributions designated by CME to be used in the event of a default of a cleared interest rate swap clearing firm. CME maintains a 364-day multi-currency line of credit with a consortium of domestic and international banks to be used in certain situations by the clearing house. CME may use the proceeds to provide temporary liquidity in the unlikely event of a clearing firm default, in the event of a liquidity constraint or default by a depositary (custodian of the collateral), or in the event of a temporary disruption with the domestic payments system that would delay payment of settlement variation between CME and its clearing firms. Clearing firm guaranty fund contributions received in the form of cash or U.S. Treasury securities as well as the performance bond assets of a defaulting firm can be used to collateralize the facility. The line of credit provides for borrowings of up to $7.0 billion. At December 31, 2023, guaranty fund contributions available to collateralize the facility were $8.6 billion. CME has the option to request an increase in the line from $7.0 billion to $10.0 billion, subject to the approval of participating banks. In addition to the 364-day fully secured, committed multi-currency line of credit, the company also has the option to use the $2.3 billion multi-currency revolving senior credit facility to provide liquidity for the clearing house in the unlikely event of default. The clearing house is required under the Commodity Exchange Act in the U.S. to segregate cash and securities deposited by clearing firms from its clearing member customers. In addition, the clearing house requires segregation of all funds deposited by its clearing firms from operating funds. Cash and non-cash deposits held as performance bonds and guaranty fund contributions at fair value at December 31, 2023 and 2022 were as follows: 2023 2022 (in millions) Cash Non-Cash Deposits and IEF Funds (1) Cash Non-Cash Deposits and IEF Funds (1) Performance bonds $ 87,285.5 $ 180,866.3 $ 132,653.7 $ 94,127.2 Guaranty fund contributions 2,379.6 6,849.6 2,450.3 5,026.0 Cross-margin arrangements 183.1 1,374.5 142.6 561.1 Other (2) 344.3 2.1 2.6 2.1 Total $ 90,192.5 $ 189,092.5 $ 135,249.2 $ 99,716.4 _______________ (1) IEF funds include customer-directed investments in IEF funds that are not included on the consolidated balance sheets. (2) Other includes collateral for delivery and accrued interest earned on collateral reinvestment due to the clearing firms. Cross-margin arrangements include collateral for the cross-margin accounts with OCC and FICC. Cash performance bonds may include intraday settlement, if any, that is owed to the clearing firms and paid the following business day. The balance of intraday settlements was $237.5 million and $436.7 million at December 31, 2023 and 2022, respectively. Intraday settlements may be invested on an overnight basis and are offset by an equal liability owed to clearing firms. In addition to cash, securities and other non-cash deposits, irrevocable letters of credit may be used as performance bond deposits for clearing firms. At December 31, 2023 and 2022, these letters of credit, which are not included in the accompanying consolidated balance sheets, were as follows: (in millions) 2023 2022 Performance bonds $ 3,916.7 $ 4,674.3 Performance bond collateral for delivery 4,631.4 3,445.0 Total Letters of Credit $ 8,548.1 $ 8,119.3 All cash, securities and letters of credit posted as performance bonds are only available to meet the financial obligations of that clearing firm to the clearing house.

Property

Property	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment, Net [Abstract]
Property	PROPERTY A summary of the property accounts at December 31, 2023 and 2022 is presented below: (in millions) 2023 2022 Estimated Useful Life Building and building improvements $ 130.7 $ 132.2 1 - 10 years Leasehold improvements 143.7 224.8 3 - 19 years Furniture, fixtures and equipment 413.3 551.3 2 - 7 years Software and software development costs 654.9 692.4 2 - 4 years Total property 1,342.6 1,600.7 Less accumulated depreciation and amortization (933.1) (1,145.2) Property, net $ 409.5 $ 455.5

Intangible Assets and Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	INTANGIBLE ASSETS AND GOODWILL Intangible assets consisted of the following at December 31, 2023 and 2022: 2023 2022 (in millions) Assigned Value Accumulated Net Book Assigned Value Accumulated Net Book Amortizable Intangible Assets: Clearing firm, market data and other customer relationships $ 4,694.4 $ (2,124.9) $ 2,569.5 $ 4,685.8 $ (1,909.7) $ 2,776.1 Technology-related intellectual property 62.5 (62.2) 0.3 62.5 (55.8) 6.7 Other 71.6 (41.2) 30.4 69.5 (32.6) 36.9 Total Amortizable Intangible Assets $ 4,828.5 $ (2,228.3) $ 2,600.2 $ 4,817.8 $ (1,998.1) $ 2,819.7 Indefinite-Lived Intangible Assets: Trade names 450.0 450.0 Total Intangible Assets—Other, Net $ 3,050.2 $ 3,269.7 Trading products (1) $ 17,175.3 $ 17,175.3 _______________ (1) Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the CFTC. Product authorizations from the CFTC have no term limits. The originally assigned useful lives for the amortizable intangible assets as of December 31, 2023 are as follows: Clearing firm, market data and other customer relationships 5 - 30 years Technology-related intellectual property 5 - 9 years Other 3 - 24.5 years Total amortization expense for intangible assets was $226.6 million, $227.7 million and $237.6 million for the years ended December 31, 2023, 2022 and 2021, respectively. As of December 31, 2023, the future estimated amortization expense related to amortizable intangible assets is expected to be as follows: (in millions) 2024 $ 222.2 2025 222.2 2026 222.2 2027 220.9 2028 214.5 Thereafter 1,498.2 Goodwill activity consisted of the following for the years ended December 31, 2023 and 2022 : (in millions) Balance at December 31, 2022 Other Activity (1) Balance at December 31, 2023 CBOT Holdings $ 5,066.4 $ — $ 5,066.4 NYMEX Holdings 2,462.2 — 2,462.2 NEX 2,913.5 17.3 2,930.8 Other 40.4 (4.5) 35.9 Total Goodwill $ 10,482.5 $ 12.8 $ 10,495.3 (in millions) Balance at December 31, 2021 Other Activity (1) Balance at December 31, 2022 CBOT Holdings $ 5,066.4 $ — $ 5,066.4 NYMEX Holdings 2,462.2 — 2,462.2 NEX 2,959.0 (45.5) 2,913.5 Other 40.4 — 40.4 Total Goodwill $ 10,528.0 $ (45.5) $ 10,482.5 _______________ 1) Other activity includes currency translation adjustments.

Long-term Investments

Long-term Investments	12 Months Ended
	Dec. 31, 2023
Long-Term Investments [Abstract]
Long-term Investments	LONG-TERM INVESTMENTS The company maintains various long-term investments as described below. The investments are recorded in other assets on the consolidated balance sheets. DME Holdings Limited. The company owns a 50% interest in DME Holdings Limited (DME Holdings), and accounts for its investment in DME Holdings using the equity method of accounting. The carrying amount of the company's investment in DME Holdings was $13.8 million at December 31, 2023. The company and DME Holdings maintain an agreement for Dubai Mercantile Exchange futures contracts to be exclusively traded on the CME Globex platform. OSTTRA. In January 2021, the company announced that it agreed with IHS Markit to combine their post-trade services into a new joint venture. The joint venture, OSTTRA, was launched in September 2021. OSTTRA performs trade processing and risk mitigation services. The company contributed the net assets of its optimization business, which included Traiana, TriOptima and Reset, to the new joint venture in exchange for $112.5 million in cash and a 50% equity interest in OSTTRA. In September 2021, the company deconsolidated its optimization business. The company recognized a net gain of $400.7 million on the transaction in other non-operating income on the consolidated statements of net income during 2021. The company accounts for its investment using the equity method of accounting. The carrying amount of the company's investment in OSTTRA was $1.3 billion at December 31, 2023. S&P Dow Jones Indices LLC. In June 2022, the company invested $410.0 million in S&P Dow Jones Indices LLC, which S&P Dow Jones Indices LLC used as part of the consideration for its acquisition of the IHS Markit index business. The company continues to own a 27% interest in S&P Dow Jones Indices LLC and accounts for its investment in S&P Dow Jones Indices LLC using the equity method of accounting. The carrying amount of the company's investment in S&P Dow Jones Indices LLC was $1.4 billion at December 31, 2023. The company has long-term exclusive licensing agreements with S&P Dow Jones Indices LLC to list products based on the Standard & Poor's Indices and Dow Jones Indices. Shanghai CFETS-NEX International Money Broking Co., Ltd. The company owns a 33% interest in Shanghai CFETS-NEX International Money Broking Co., Ltd. (CFETS) and accounts for its investment in CFETS using the equity method of accounting. The carrying amount of the company's investment in CFETS was $51.3 million

Debt

Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	DEBT In May 2023, the company repaid the €15.0 million fixed rate notes. Short-term debt consisted of the following at December 31, 2023 and 2022 (in U.S. dollar equivalents): (in millions) 2023 2022 €15.0 million fixed rate notes due May 2023, stated rate of 4.30% $ — $ 16.0 Total short-term debt $ — $ 16.0 Long-term debt outstanding consisted of the following at December 31, 2023 and 2022 (in U.S. dollar equivalents): (in millions) 2023 2022 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (1) $ 749.1 $ 748.4 $500.0 million fixed rate notes due June 2028, stated rate of 3.75% 498.1 497.7 $750.0 million fixed rate notes due March 2032, stated rate of 2.65% 742.9 741.7 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (2) 744.0 743.7 $700.0 million fixed rate notes due June 2048, stated rate of 4.15% 691.3 690.9 Total long-term debt $ 3,425.4 $ 3,422.4 _______________ (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 3.11%. (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 4.73%. Short term and long-term debt maturities, at par value (in U.S. dollar equivalents), were as follows as of December 31, 2023: (in millions) Par Value 2024 $ — 2025 750.0 2026 — 2027 — 2028 500.0 Thereafter 2,200.0

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The company is subject to regulation under a wide variety of U.S., federal, state and foreign tax laws and regulations. Income before income taxes and the income tax provision consisted of the following for the years ended December 31, 2023 and 2022 and 2021: (in millions) 2023 2022 2021 Income before income taxes: Domestic $ 3,900.5 $ 3,291.7 $ 2,728.5 Foreign 253.1 198.6 645.1 Total $ 4,153.6 $ 3,490.3 $ 3,373.6 Income tax provision: Current: Federal $ 751.7 $ 620.5 $ 509.2 State 205.8 177.1 173.7 Foreign 44.9 24.9 19.0 Total 1,002.4 822.5 701.9 Deferred: Federal 21.9 (16.3) (4.6) State (33.8) (7.3) 10.6 Foreign (63.1) 0.4 28.8 Total (75.0) (23.2) 34.8 Total Income Tax Provision $ 927.4 $ 799.3 $ 736.7 Reconciliation of the U.S. federal income tax rate (statutory tax rate) to the effective tax rate is as follows: 2023 2022 2021 Statutory tax rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 3.3 3.9 4.3 Gain on formation of OSTTRA — — (2.5) Statutory rate change — — 1.1 Foreign-derived intangible income deduction (1.5) (1.5) (1.6) Other, net (0.5) (0.5) (0.5) Effective Tax Expense Benefit Rate 22.3 % 22.9 % 21.8 % In 2023 and 2022, the effective tax rates were higher than the statutory tax rate. The increases to the effective tax rate for the state taxes were partially offset by the foreign-derived intangible income (FDII) deduction. In 2021, the effective tax rate was higher than the statutory tax rate. The increase to the effective tax rate for the state taxes and the impact of the statutory rate change in the United Kingdom was partially offset by the non-taxable gain on the formation of OSTTRA and the FDII deduction. At December 31, 2023 and 2022, deferred income tax assets (liabilities) consisted of the following: (in millions) 2023 2022 Deferred Income Tax Assets: Net operating losses $ 3.4 $ 3.7 Accrued expenses, compensation, leases and other 131.4 135.2 Subtotal 134.8 138.9 Valuation allowance (0.4) (0.4) Total deferred income tax assets 134.4 138.5 Deferred Income Tax Liabilities: Purchased intangible assets (5,298.2) (5,358.8) Other (115.4) (106.3) Property (1.3) (30.4) Total deferred income tax liabilities (5,414.9) (5,495.5) Net Deferred Income Tax Liabilities $ (5,280.5) $ (5,357.0) Reported as: Net non-current deferred tax assets $ 47.2 $ 4.1 Net non-current deferred tax liabilities (5,327.7) (5,361.1) Net Deferred Income Tax Liabilities $ (5,280.5) $ (5,357.0) A valuation allowance is recorded when it is more-likely-than-not that some portion or all of the deferred income tax assets may not be realized. The ultimate realization of the deferred income tax assets depends on the ability to generate sufficient taxable income of the appropriate character in the future and in the appropriate taxing jurisdictions. At December 31, 2023 and 2022, the company had domestic and foreign income tax loss carry forwards of $16.0 million and $17.6 million, respectively. These amounts primarily related to losses from the acquisition of NEX Group plc, the acquisition of Pivot, Inc., and losses incurred in the operation of various foreign entities. At December 31, 2023 and 2022, the company determined that it was not more-likely-than-not that certain foreign deferred income tax assets will be fully realized. As a result, valuation allowances of $0.4 million was recorded at December 31, 2023 and 2022. The following is a summary of the company’s unrecognized tax benefits at December 31, 2023, 2022 and 2021: (in millions) 2023 2022 2021 Gross unrecognized tax benefits $ 264.1 $ 280.3 $ 316.4 Unrecognized tax benefits, net of tax impacts in other jurisdictions 251.9 264.4 293.1 Interest and penalties related to uncertain tax positions 16.6 28.0 42.8 Interest and penalties recognized on the consolidated statements of income (4.0) (3.8) 5.3 The company does not believe it is reasonably possible that within the next twelve months, unrecognized tax benefits will change by a significant amount. A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits is as follows: (in millions) 2023 2022 2021 Balance at January 1 $ 280.3 $ 316.4 $ 328.2 Additions based on tax positions related to the current year 10.0 8.5 10.2 Additions for tax positions of prior years 4.3 2.7 9.6 Reductions for tax positions of prior years (8.0) (9.5) (5.1) Reductions resulting from the lapse of statutes of limitations (5.2) (5.5) (0.3) Settlements with taxing authorities (17.3) (32.3) (26.2) Balance at December 31 $ 264.1 $ 280.3 $ 316.4

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2023
Retirement Benefits, Description [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS Pension Plans. CME maintains a non-contributory defined benefit cash balance pension plan for eligible employees. CME's plan provides for a pay-based credit added to the cash balance account based on age and earnings and includes salary and cash bonuses in the definition of earnings. Employees who have completed a continuous 12-month period of employment and have reached the age of 21 are eligible to participate. Participant cash balance accounts receive an interest credit equal to the greater of the one-year constant maturity yield for U.S. Treasury notes or 4.0%. Participants become vested in their accounts after three years of service. The measurement date used for the plan is December 31. The following is a summary of the change in projected benefit obligation: (in millions) 2023 2022 Balance at January 1 $ 316.4 $ 386.0 Service cost 21.1 25.7 Interest cost 18.5 12.0 Actuarial (gain) loss 18.3 (86.7) Benefits paid (22.8) (20.6) Balance at December 31 $ 351.5 $ 316.4 The aggregate accumulated benefit obligation was $323.2 million and $294.4 million at December 31, 2023 and 2022, respectively. The following is a summary of the change in fair value of plan assets: (in millions) 2023 2022 2021 Balance at January 1 $ 331.7 $ 402.3 $ 388.2 Actual return on plan assets 38.9 (50.0) 34.0 Employer contributions 3.0 — — Benefits paid (22.8) (20.6) (19.9) Balance at December 31 $ 350.8 $ 331.7 $ 402.3 The plan assets are classified into a fair value hierarchy in their entirety based on the lowest level of input that is significant to each asset or liability’s fair value measurement. Valuation techniques for level 2 assets use significant observable inputs such as quoted prices for similar assets, quoted market prices in inactive markets and other inputs that are observable or can be supported by observable market data. The fair value of each major category of plan assets as of December 31, 2023 and 2022 is indicated below: (in millions) 2023 2022 Level 2: Money market funds $ 6.2 $ 16.6 Mutual funds: Fixed income 165.3 131.6 U.S. equity 131.6 129.8 Foreign equity 47.7 53.7 Total $ 350.8 $ 331.7 At December 31, 2023, the fair value of pension plan assets had a shortfall of the projected benefit obligation by $0.7 million and the shortfall was recorded as a non-current pension liability in other liabilities. At December 31, 2022, the fair value of pension plan assets exceeded the pension benefit obligation by $15.3 million and the excess was recorded as a non-current pension asset in other assets. CME's funding goal is to have its pension plan 100% funded at each year-end on a projected benefit obligation basis, while also satisfying any minimum required contribution and obtaining the maximum tax deduction. Year-end 2023 assumptions have been used to project the assets and liabilities from December 31, 2023 to December 31, 2024. The company anticipates based on this projection that an additional contribution of $16.9 million in 2024 will be necessary for it to meet its funding goal. However, the amount of the actual contribution is contingent on various factors, including the actual rate of return on the plan assets during 2024 and the December 31, 2024 discount rate. The components of net pension expense and the assumptions used to determine the end-of-year projected benefit obligation and net pension expense in aggregate at December 31, 2023 and 2022 and 2021 are indicated below: (in millions) 2023 2022 2021 Components of Net Pension Expense: Service cost $ 21.1 $ 25.7 $ 27.8 Interest cost 18.5 12.0 10.7 Expected return on plan assets (21.6) (22.3) (21.7) Recognized net actuarial loss 0.3 1.4 4.5 Net Pension Expense $ 18.3 $ 16.8 $ 21.3 Assumptions Used to Determine End-of-Year Benefit Obligation: Discount rate 5.20 % 5.60 % 3.00 % Rate of compensation increase 4.00 4.00 4.00 Cash balance interest crediting rate 5.14 4.75 4.00 Assumptions Used to Determine Net Pension Expense: Discount rate 5.60 % 3.00 % 2.70 % Rate of compensation increase 4.00 4.00 4.00 Expected return on plan assets 6.75 5.75 5.75 Interest crediting rate 4.75 4.00 4.00 The discount rate for the plan was determined based on the market value of a theoretical settlement bond portfolio. This portfolio consisted of U.S. dollar denominated Aa-rated corporate bonds across the full maturity spectrum. A single equivalent discount rate was determined to align the present value of the required cash flow with that settlement value. The resulting discount rate was reflective of both the current interest rate environment and the plan's distinct liability characteristics. The basis for determining the expected rate of return on plan assets for the plan is comprised of three components: historical returns, industry peers and forecasted return. The plan's total return is expected to equal the composite performance of the security markets over the long term. The security markets are represented by the returns on various domestic and international stock, bond and commodity indexes. These returns are weighted according to the allocation of plan assets to each market and measured individually. The overall objective of the plan is to achieve required long-term rates of return in order to meet future benefit payments. The component of the investment policy for the plan that has the most significant impact on returns is the asset mix. The asset mix has a minimum and maximum range depending on asset class. The plan assets are diversified to minimize the risk of large losses by any one or more individual assets. Such diversification is accomplished, in part, through the selection of asset mix and investment management. The asset allocation for the plan, by asset category, at December 31, 2023 and 2022 was as follows: 2023 2022 Fixed income 47.1 % 39.7 % Money market funds 1.8 5.0 U.S. equity 37.5 39.1 Foreign equity 13.6 16.2 For 2024, management expects the fixed income asset class to be approximately 50% of the portfolio. The target allocation for the equity asset classes is expected to be approximately 50% of the portfolio. At times, the company may determine that it is necessary to place some assets in cash equivalent investments in order to pay expected plan liabilities. Given this, the actual asset allocation for the plan may not fall within the target allocation ranges from time to time. According to the plan's investment policy, the plan is not allowed to invest in securities that compromise independence, short sales of securities directly owned by the plan, securities purchased on margin or other uses of borrowed funds, derivatives not used for hedging purposes, restricted stock or illiquid securities or any other transaction prohibited by employment laws. If the plan directly invests in short-term and long-term debt obligations, the investments are limited to obligations rated at the highest rating category by Standard & Poor's or Moody's. The pre-tax balance and activity of actuarial losses for the pension plan, which are included in other comprehensive income (loss), for 2023 are as follows: (in millions) Actuarial Balance at January 1 $ 32.2 Unrecognized net loss 1.1 Recognized as a component of net pension expense (0.3) Balance at December 31 $ 33.0 At December 31, 2023, anticipated benefit payments from the plan in future years are as follows: (in millions) 2024 $ 32.1 2025 32.5 2026 33.8 2027 34.5 2028 35.2 2029-2033 182.6 Savings Plans. CME maintains a defined contribution savings plan pursuant to Section 401(k) of the Internal Revenue Code, whereby all U.S. employees are participants and have the option to contribute to this plan. CME matches employee contributions up to 3% of the employee's base salary and may make additional discretionary contributions. In addition to the plan for U.S. employees, the company maintains defined contribution savings plans for employees in international locations. Aggregate expense for all of the defined contribution savings plans amounted to $19.7 million , $18.3 million and $24.7 million in 2023, 2022 and 2021, respectively. CME Non-Qualified Plans. CME maintains non-qualified plans, under which participants may make assumed investment choices with respect to amounts contributed on their behalf. Although not required to do so, CME invests such contributions in assets that mirror the assumed investment choices. The balances in these plans are subject to the claims of general creditors of the company and totaled $101.3 million and $84.5 million at December 31, 2023 and 2022, respectively. Although the value of the plans is recorded as an asset in marketable securities on the consolidated balance sheets, there is an equal and offsetting liability. The investment results of these plans have no impact on net income as the investment results are recorded in equal amounts to both investment income and compensation and benefits expense. The non-qualified plans include the following: Supplemental Savings Plan. CME maintains a supplemental plan to provide benefits for employees who have been impacted by statutory limits under the provisions of the qualified pension and savings plan. Employees in this plan are subject to the vesting requirements of the underlying qualified plans. Deferred Compensation Plan. A deferred compensation plan is maintained by CME, under which eligible employees and members of the board of directors may contribute a percentage of their compensation and defer income taxes thereon until the time of distribution. COMEX Members' Retirement Plan and Benefits. COMEX maintains a non-qualified retirement and benefit plan under the COMEX Members' Retirement Plan and Benefits plan (MRRP). This plan provides benefits to certain members of the COMEX division based on long-term membership, and participation is limited to individuals who were COMEX division members prior to NYMEX's acquisition of COMEX in 1994. No new participants were permitted into the plan after the date of this acquisition. All benefits to be paid under the MRRP are based on reasonable actuarial assumptions, which are based upon the amounts that are available and are expected to be available to pay benefits. There w ere no co ntributions to the plan in 2023, 2022 and 2021. At December 31, 2023 and 2022, the obligation for the MRRP totaled $8.7 million and $10.3 million, respectively . Assets with a fair value of $10.8 million and $12.0 million have been allocated to this plan at December 31, 2023 and 2022, respectively, and are included in marketable securities and cash and cash equivalents on the consolidated balance sheets. The balances in this plan are subject to the claims of general creditors of COMEX.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2023
Other Commitments [Abstract]
Leases, Operating and Finance	LEASES Leases. The company has operating leases for datacenters and corporate offices. The operating leases have remaining lease terms of up to 14 years, some of which include options to extend or renew the leases for up to an additional five years, and some of which include options to early terminate the leases in less than 12 months. Management evaluates the exercisability of these options at least quarterly in order to determine whether the contract term must be reassessed. For a small number of the leases, primarily the international locations, management's approach is to enter into short-term leases for a lease term of 12 months or less in order to provide for greater flexibility in the local environment. For certain office spaces, the company has entered into arrangements to sublease excess space to third parties, while the original lease contract remains in effect with the landlord. The company also has one finance lease, which is related to the sale of our datacenter in March 2016. In connection with the sale, the company leased back a portion of the property. The sale leaseback transaction was recognized under the financing method and not as a sale leaseback arrangement. The right-of-use lease asset is recorded within other assets, and the present value of the lease liability is recorded within other liabilities (segregated between short-term and long-term) on the consolidated balance sheets. The discount rate applied to the lease payments represents the company's incremental borrowing rate. The company has elected to utilize the short-term lease exception as prescribed in the leasing standard, such that the company has not capitalized on the balance sheet a lease asset or lease liability for leasing arrangements with a contractual term of 12 months or less from the lease commencement date. The components of lease costs were as follows for the years ended December 31, 2023 and 2022: (in millions) 2023 2022 Operating lease expense: Operating lease cost $ 55.1 $ 56.9 Short-term lease cost 0.4 0.4 Total operating lease expense included in other expense $ 55.5 $ 57.3 Finance lease expense: Interest expense $ 2.5 $ 2.8 Depreciation expense 8.7 8.7 Total finance lease expense $ 11.2 $ 11.5 Sublease revenue included in other revenue $ 9.8 $ 10.6 Supplemental cash flow information related to leases was as follows for years ended December 31, 2023 and 2022: (in millions) 2023 2022 Cash outflows for operating leases $ 66.2 $ 65.4 Cash outflows for finance leases 17.2 17.1 Supplemental balance sheet information related to leases was as follows as of December 31, 2023 and 2022: Operating leases (in millions) 2023 2022 Operating lease right-of-use assets $ 272.0 $ 310.6 Operating lease liabilities: Other current liabilities $ 46.7 $ 49.9 Other liabilities 344.0 383.5 Total operating lease liabilities $ 390.7 $ 433.4 Weighted average remaining lease term (in months) 114 121 Weighted average discount rate 3.8 % 3.8 % Finance leases (in millions) 2023 2022 Finance lease right-of-use assets $ 62.8 $ 71.5 Finance lease liabilities: Other current liabilities $ 8.4 $ 8.2 Other liabilities 59.4 67.8 Total finance lease liabilities $ 67.8 $ 76.0 Weighted average remaining lease term (in months) 87 99 Weighted average discount rate 3.5 % 3.5 % Future minimum lease payments were as follows as of December 31, 2023 for operating and finance leases: (in millions) Operating Leases 2024 $ 60.5 2025 57.4 2026 52.8 2027 50.3 2028 49.6 Thereafter 192.5 Total lease payments 463.1 Less: imputed interest (72.4) Present value of lease liability $ 390.7 (in millions) Finance Lease 2024 $ 17.4 2025 17.5 2026 17.6 2027 17.8 2028 17.9 Thereafter 41.0 Total lease payments 129.2 Less: imputed interest (61.4) Present value of lease liability $ 67.8

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Contingencies	CONTINGENCIES Legal and Regulatory Matters. 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 the company's 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. A putative class action complaint was filed January 15, 2014 in the Circuit Court of Cook County, Chancery Division, against CME Group Inc. and the Board of Trade of the City of Chicago, Inc. The plaintiffs, certain Class B shareholders of CME Group and Class B members of CBOT, allege breach of contract and breach of the implied covenant of good faith and fair dealing for violations of their core rights granted in the defendants’ respective Certificates of Incorporation. On December 2, 2021, the court granted the plaintiffs’ motion for certification of a damages-only class. No trial date has been set. Given the uncertainty of factors that may potentially affect the resolution of the matter, at this time the company is unable to estimate the reasonably possible loss or range of reasonably possible losses in the unlikely event it were found to be liable at trial. Based on its investigation to date, the company believes that it has strong factual and legal defenses to the claims. 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 contingent legal and regulatory matters as none were probable and estimable as of December 31, 2023 and 2022. Intellect ual Property Indemnifications. Certain agreements with customers and other third parties related to accessing the CME Group platforms, utilizing market data services and licensing CME SPAN software may contain indemnifications from intellectual property claims that may be made against them as a result of their use of the applicable products and/or services. The potential future claims relating to these indemnifications cannot be estimated and therefore no liability has been recorded.

Guarantees

Guarantees	12 Months Ended
	Dec. 31, 2023
Guarantees [Abstract]
Guarantees	GUARANTEES Mutual Offset Agreement. CME and Singapore Exchange Limited (SGX) maintain a mutual offset agreement with a current term through May 2024. 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 after May 2024 unless either party provides advance notice of its intent to terminate. CME can maintain collateral in the form of irrevocable standby letters of credit. At December 31, 2023, CME was contingently liable to SGX on irrevocable letters of credit totaling $285.0 million . CME also maintains a $350.0 million line of credit to meet its obligations under this agreement. 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. Management has assessed the fair value of the company's guarantee liability under this mutual offset agreement by taking the following factors into consideration: the design and operations of the clearing risk management process, the financial safeguard packages in place, historical evidence of default by a clearing member and the estimated probability of potential payouts by the clearing house. Based on the assessment performed, management estimates the guarantee liability to be nominal and therefore has not recorded any liability at December 31, 2023. 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 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 has an aggregate maximum payment amount of $100.0 million. Since its establishment, the Fund has made payments of approximately $2.0 million, which leaves $98.0 million available for future claims. If payments to participants were to exceed this amount, payments would be pro-rated. Clearing members and customers must register in advance with the company and provide certain documentation in order to substantiate their eligibility . The company believes that its guarantee liability is nominal and therefore has not recorded any liability at December 31, 2023.

Capital Stock

Capital Stock	12 Months Ended
	Dec. 31, 2023
Capital Stock [abstract]
Capital Stock	CAPITAL STOCK Shares Outstanding. The following table presents information regarding capital stock: December 31, (in thousands) 2023 2022 Preferred stock authorized 10,000 10,000 Preferred stock issued and outstanding 4,584 4,584 Class A common stock authorized 1,000,000 1,000,000 Class A common stock issued and outstanding 359,231 358,929 Class B-1 common stock authorized, issued and outstanding 0.6 0.6 Class B-2 common stock authorized, issued and outstanding 0.8 0.8 Class B-3 common stock authorized, issued and outstanding 1.3 1.3 Class B-4 common stock authorized, issued and outstanding 0.4 0.4 Preferred Stock. CME Group has approximately 4.6 million shares of Series G Non-Voting Convertible Preferred Stock (Series G preferred stock) outstanding. The Series G preferred stock is non-voting and is convertible into Class A common stock at a specified conversion rate, which is initially 1:1. The Series G preferred stock ranks on a parity basis with the Class A common stock with respect to dividend and liquidation rights and therefore participates in the earnings and losses of CME Group on the same basis as Class A common stock. Associated Trading Rights. Members of CME, CBOT, NYMEX and COMEX own or lease trading rights which entitle them access to open outcry trading, discounts on trading fees and the right to vote on certain matters as provided for by the rules of the particular exchange and CME Group's or the subsidiary's organizational documents. Each class of CME Group Class B common stock is associated with a membership in a specific division for trading at CME. A CME trading right is a separate asset that is not part of or evidenced by the associated share of Class B common stock of CME Group. The Class B common stock of CME Group is intended only to ensure that the Class B shareholders of CME Group retain rights with respect to the election of six members to the board of directors and approval rights with respect to the core rights described below. Trading rights at CBOT are evidenced by Class B memberships in CBOT, at NYMEX by Class A memberships in NYMEX and at COMEX by COMEX Division Memberships. Members of CBOT, NYMEX and COMEX do not have any rights to elect members of the board of directors and are not entitled to receive dividends or other distributions on their memberships or trading permits. Core Rights. Holders of CME Group Class B common shares have the right to approve changes in specified rights relating to the trading privileges at CME associated with those shares. These core rights relate primarily to trading right protections, certain trading fee protections and certain membership benefit protections. Votes on changes to these core rights are weighted by class. Each class of Class B common stock has the following number of votes on matters relating to core rights: Class B-1, six votes per share; Class B-2, two votes per share; Class B-3, one vote per share; and Class B-4, 1/6th of one vote per share. The approval of a majority of the votes cast by the holders of shares of Class B common stock is required in order to approve any changes to core rights. Holders of shares of Class A common stock do not have the right to vote on changes to core rights. Voting Rights. With the exception of the matters reserved to holders of CME Group Class B common stock, holders of CME Group common stock vote together on all matters for which a vote of common shareholders is required. In these votes, each holder of shares of Class A or Class B common stock of CME Group has one vote per share. The holder of Series G preferred stock does not have any voting rights. Transfer Restrictions. Each class of CME Group Class B common stock is subject to transfer restrictions contained in the Certificate of Incorporation of CME Group. These transfer restrictions prohibit the sale or transfer of any shares of Class B common stock separate from the sale of the associated trading rights. Election of Directors. The CME Group board of directors is currently comprised of 23 members. Holders of Class B-1, Class B-2 and Class B-3 common stock have the right to elect six directors, of which three are elected by Class B-1 shareholders, two are elected by Class B-2 shareholders and one is elected by Class B-3 shareholders. The remaining directors are elected by the Class A and Class B shareholders voting as a single class. Dividends. Holders of Class A and Class B common stock and Series G preferred stock of CME Group are entitled to receive proportionately such dividends, if any, as may be declared by the CME Group board of directors. CME Group Omnibus Stock Plan. CME Group has adopted an Omnibus Stock Plan under which stock-based awards may be made to employees. A total of 40.2 million Class A common stock shares have been reserved for awards under the plan. Awards totaling 25.6 million shares have been granted and are outstanding or have been exercised under this plan at December 31, 2023 (See note 15 for further discussion). Director Stock Plan. CME Group has adopted a Director Stock Plan under which awards are made to non-executive directors as part of their annual compensation. Effective May 4, 2022, the number of Class A available shares reserved under the plan was increased from 625,000 to 725,000, and approximately 469,322 shares have been awarded through December 31, 2023. Employee Stock Purchase Plan.

Stock-Based Payments

Stock-Based Payments	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Stock-Based Payments	STOCK-BASED PAYMENTS CME Group adopted an Omnibus Stock Plan under which stock-based awards may be made to employees. A total of 40.2 million Class A shares have been reserved for awards under the plan. Awards totaling 25.6 million shares have been granted and are outstanding or have been exercised under the plan as of December 31, 2023. Awards granted generally vest over a four-year period, with 25% vesting one year after the grant date and on that same date in each of the following three years. Total compensation expense for all stock-related awards (including ESPP) and total income tax benefit recognized on the consolidated statements of income for these awards at December 31, 2023 and 2022 and 2021 were as follows: (in millions) 2023 2022 2021 Compensation expense $ 83.7 $ 84.8 $ 76.4 Income tax benefit recognized 14.2 13.2 20.6 At December 31, 2023, there was $131.1 million of total unrecognized compensation expense related to employee stock-based compensation arrangements that had not yet vested. The total unrecognized expense is expected to be recognized over a weighted average period of 2.2 years. In 2023, the company granted 370,024 shares of restricted Class A common stock and restricted stock units with respect to 10,774 shares of Class A common stock. Restricted common stock and restricted stock units generally have a vesting period of two to four years. The fair value related to these grants was $78.4 million, which is recognized as compensation expense on an accelerated basis over the vesting period. Dividends are accrued on restricted Class A common stock and restricted stock units and are paid once the restricted stock vests. In 2023, the company also granted 84,397 performance shares. The fair value related to these grants was $19.0 million, which is recognized as compensation expense on a straight-lined basis over the vesting period. The vesting of these shares is contingent on meeting stated performance or market conditions, generally measured over a three-year period. The following table summarizes restricted stock, restricted stock units and performance shares activity for 2023: Number of Shares Weighted Outstanding at December 31, 2022 1,117,459 $ 204 Granted 468,675 206 Vested (240,707) 190 Cancelled (245,547) 209 Outstanding at December 31, 2023 1,099,880 204 The total fair value of restricted stock, restricted stock units and performance shares that vested during 2023, 2022 and 2021 was $49.6 million, $52.2 million and $65.7 million, respectively. Under the ESPP, eligible employees may acquire shares of Class A common stock using after-tax payroll deductions made during consecutive offering periods of approximately six months in duration. Shares are purchased at the end of each offering period at a price of 90% of the closing price of the Class A common stock as reported on the Nasdaq Global Select Market. Compensation expense is recognized on the dates of purchase for the discount from the closing price. In 2023, 2022 and 2021, a total of 40,960, 41,722 and 37,861 shares, respectively, of Class A common stock were issued to participating employees. These shares are subject to a six-month holding period. Annual expense of $0.8 million for the purchase discount was recognized in 2023, 2022 and 2021.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Comprehensive Income (Loss) Note [Text Block]	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 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, 2022 $ (0.9) $ (22.8) $ 64.7 $ (174.3) $ (133.3) Other comprehensive income before reclassifications and income tax benefit (expense) 0.6 (0.9) — 70.8 70.5 Reclassification adjustment for loss included in net income — — — 9.7 9.7 Amounts reclassified from accumulated other comprehensive income — 0.1 (3.6) — (3.5) Income tax benefit (expense) (0.1) 0.2 0.9 — 1.0 Net current period other comprehensive income 0.5 (0.6) (2.7) 80.5 77.7 Balance at December 31, 2023 $ (0.4) $ (23.4) $ 62.0 $ (93.8) $ (55.6) (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2021 $ 1.1 $ (34.8) $ 66.1 $ 21.1 $ 53.5 Other comprehensive income before reclassifications and income tax benefit (expense) (2.7) 14.9 — (195.4) (183.2) Amounts reclassified from accumulated other comprehensive income — 1.2 (1.9) — (0.7) Income tax benefit (expense) 0.7 (4.1) 0.5 — (2.9) Net current period other comprehensive income (2.0) 12.0 (1.4) (195.4) (186.8) Balance at December 31, 2022 $ (0.9) $ (22.8) $ 64.7 $ (174.3) $ (133.3) (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2020 $ 1.6 $ (57.1) $ 67.0 $ 123.4 $ 134.9 Other comprehensive income before reclassifications and income tax benefit (expense) (1.0) 25.5 — (62.0) (37.5) Amounts reclassified from accumulated other comprehensive income 0.3 4.4 (1.2) (40.3) (36.8) Income tax benefit (expense) 0.2 (7.6) 0.3 — (7.1) Net current period other comprehensive income (0.5) 22.3 (0.9) (102.3) (81.4) Balance at December 31, 2021 $ 1.1 $ (34.8) $ 66.1 $ 21.1 $ 53.5

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [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. The company’s 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. The company’s level 2 assets and liabilities generally consist of long-term debt notes. The fair values of the long-term debt notes were based on quoted market prices in an inactive market. The company’s level 3 assets and liabilities include certain investments that were adjusted to fair value. Recurring Fair Value Measurements. Financial assets recorded at fair value on the consolidated balance sheets as of December 31, 2023 and 2022 were classified in their entirety based on the lowest level of input that was significant to each asset's fair value measurement. Financial Instruments Measured at Fair Value on a Recurring Basis: December 31, 2023 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 10.2 $ — $ — $ 10.2 Mutual funds 101.3 — — 101.3 Equity securities 0.2 — — 0.2 Total Marketable Securities 111.7 — — 111.7 Total Assets at Fair Value $ 111.7 $ — $ — $ 111.7 December 31, 2022 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 11.3 $ — $ — $ 11.3 Mutual funds 84.5 — — 84.5 Equity securities 0.2 — — 0.2 Total Marketable Securities 96.0 — — 96.0 Total Assets at Fair Value $ 96.0 $ — $ — $ 96.0 Non-Recurring Fair Value Measurements. During 2023, t he company recognized net unrealized losses of $1.4 million on equity investments without readily determinable fair value. The fair value of these investments were estimated to be $8.6 million at December 31, 2023. This fair value assessments were based on quantitative factors, including observable price changes. The fair value measurements of these investments are considered level 3 and non-recurring. Fair Values of Debt Notes. The follo wing 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 are classified as level 2 under the fair value hierarchy and were estimated using quoted market prices in inactive markets. At December 31, 2023, the fair values (in U.S. dollar equivalents) were as follows: (in millions) Fair Value Level $750.0 million fixed rate notes due March 2025 733.8 Level 2 $500.0 million fixed rate notes due June 2028 489.3 Level 2 $750.0 million fixed rate notes due March 2032 669.0 Level 2 $750.0 million fixed rate notes due September 2043 802.2 Level 2 $700.0 million fixed rate notes due June 2048 641.0 Level 2

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The company uses the two-class method to calculate basic and diluted earnings per common share because its Series G preferred stock are participating securities. Under the two-class method, undistributed earnings are allocated to common stock and participating securities according to their respective rights in undistributed earnings, as if all of the earnings for the period had been distributed. Basic earnings per common share is computed by dividing the net income attributable to common shareholders by the weighted average number of common shares outstanding during the period. Net income attributable to common shareholders is reduced for preferred stock dividends earned during the period. Series G preferred stock also receives a proportionate allocation of undistributed or overdistributed earnings for the period because Series G preferred stock has a contractual obligation to share in profits and losses of the company. Diluted earnings per share is computed by dividing the net income attributable to common shareholders by the weighted average number of common shares outstanding plus potentially dilutive common shares. Anti-dilutive stock awards were as follows for the years presented: (in thousands) 2023 2022 2021 Stock awards 455 158 86 Total 455 158 86 The following table presents the earnings per share calculation for the years presented: 2023 2022 2021 Net Income Attributable to CME Group (in millions) $ 3,226.2 $ 2,691.0 $ 2,636.4 Less: Preferred stock dividends (44.2) (38.9) (19.0) Less: (Undistributed earnings) overdistributed earnings allocated to preferred stock 3.6 5.1 (0.3) Net Income Attributable to Common Shareholders of CME Group $ 3,185.6 $ 2,657.2 $ 2,617.1 Weighted Average Common Shares Outstanding (in thousands): Basic 359,023 358,713 358,340 Effect of stock options and stock awards 477 468 589 Diluted 359,500 359,181 358,929 Earnings per Common Share Attributable to Common Shareholders of CME Group: Basic $ 8.87 $ 7.41 $ 7.30 Diluted 8.86 7.40 7.29

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	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 that require disclosure.

Schedule II_Valuation and Quali

Schedule II—Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2023
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]	CME Group Inc. and Subsidiaries Schedule II—Valuation and Qualifying Accounts For the Years Ended December 31, 2023, 2022 and 2021 (dollars in millions) Balance at Charged Other (1) Balance Year Ended December 31, 2023 Allowance for doubtful accounts $ 8.1 $ 0.6 $ (1.6) $ 7.1 Allowance for deferred tax assets 0.4 — — 0.4 Year Ended December 31, 2022 Allowance for doubtful accounts $ 5.6 $ 3.9 $ (1.4) $ 8.1 Allowance for deferred tax assets 0.6 — (0.2) 0.4 Year Ended December 31, 2021 Allowance for doubtful accounts $ 5.4 $ 1.9 $ (1.7) $ 5.6 Allowance for deferred tax assets 11.3 — (10.7) 0.6 _______________ (1) Includes write-offs of doubtful accounts, foreign currency and write-offs of fully reserved deferred tax assets. Other activity for the allowance for doubtful accounts also includes the impact of the adoption of new guidance on credit losses in 2020. All other schedules have been omitted because the information required to be set forth in those schedules is not applicable or is shown on the consolidated financial statements or notes thereto.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Principles of Consolidation	Basis of Presentation.
Use of Estimates	Use of Estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents.
Investment, Policy [Policy Text Block]	Financial Investments. The company maintains short-term and long-term investments, classified as equity method investments, available-for-sale debt securities, equity investments in privately-held entities and trading securities. Available-for-sale debt securities are carried at fair value, with unrealized gains and losses, net of deferred income taxes, reported as a component of accumulated other comprehensive income. Trading securities held in connection with non-qualified deferred compensation plans are recorded at fair value, with net realized and unrealized gains and losses and dividend income reported as investment income. For equity investments in privately-held entities that do not have a readily determinable fair value, our accounting policy is to utilize the measurement alternative for valuation of these investments, which permits the company to estimate fair value at cost minus impairment, plus or minus changes resulting from observable price movements. Additionally, the company maintains long-term investments accounted for under the equity method, which requires that the company recognize its share of net income (loss) and other comprehensive income (loss) in the investee as an adjustment to the carrying amount of the investment each reporting period. The company reviews its investment portfolio at least quarterly, as well as whenever facts or circumstances exist which indicate that the carrying value of an investment is greater than its fair value. For investments not carried at fair value, the carrying value of the investment is reduced to its fair value and a corresponding impairment expense is charged to earnings, if events and circumstances indicate that a markdown to fair value is warranted. Declines in the fair value of available-for-sale debt securities that are deemed to represent indicators of impairment are charged to earnings as a realized loss.
Fair Value of Financial Instruments	Fair Value of Financial Instruments.
Derivative Investments	Derivative Investments. The company occasionally uses derivative instruments to limit exposure to changes in interest rates and foreign currency exchange rates. Derivatives are recorded at fair value on the consolidated balance sheets. For those derivatives that meet the criteria for hedge accounting and are classified as effective cash flow hedges, changes in the fair value of derivative financial instruments are initially recorded in other comprehensive income and subsequently reclassified into earnings when the hedged item affects income. The company assesses, both at the inception of each hedge and on an ongoing basis, whether the derivative financial instruments that are designated as cash flow hedging transactions are highly effective in offsetting changes in cash flows of the hedged items. For any hedges no longer deemed effective or for which hedge accounting is not applied, changes in fair value of the derivative instruments are recognized in earnings within other non-operating income (expense). There were no outstanding derivative instruments at December 31, 2023.
Accounts Receivable	Accounts Receivable.
Performance Bonds and Guaranty Fund Contributions	Performance Bonds and Guaranty Fund Contributions. Performance bonds and guaranty fund contributions held for clearing firms may be in the form of cash, securities or other non-cash deposits. Performance bonds and guaranty fund contributions received in the form of cash held by CME may be invested in U.S. government securities, U.S. government agency securities and certain foreign government securities acquired through and held by a bank or broker-dealer subsidiary of a bank, a cash account at the Federal Reserve Bank of Chicago, investments in highly rated government securities, money market funds or through CME's Interest Earning Facility (IEF) program. Any interest earned on these investments accrues to CME and is included in investment income on the consolidated statements of income. CME may distribute any interest earned on its investments to the clearing firms at its discretion. Because CME has control of the cash collateral and the benefits and market risks of ownership accrue to CME, cash performance bonds and guaranty fund contributions are reflected on the consolidated balance sheets. The cash performance bonds and guaranty fund contributions are considered restricted cash as the cash deposits cannot be used for the company's operations or to satisfy any operational liabilities.
Property, Equipment and Leasehold Improvements	Property.
Operating Leases	Leases.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets. Goodwill represents the excess of the purchase price over the fair value of the net assets acquired in a business combination. The company reviews goodwill for impairment at least quarterly and whenever events or circumstances indicate that the carrying value may not be recoverable. The company may test goodwill quantitatively for impairment by comparing the carrying value of a reporting unit to its estimated fair value. Estimating the fair value of a reporting unit involves significant judgments inherent in the analysis, including estimating the amount and timing of future cash flows and the selection of appropriate discount rates and long-term growth rate assumptions. Changes in these estimates and assumptions could materially affect the determination of fair value for the reporting unit. If the carrying amount exceeds fair value, an impairment loss is recorded. In certain circumstances, goodwill may be reviewed qualitatively for indications of impairment without utilizing valuation techniques to estimate fair value. The company performs an impairment assessment of indefinite-lived intangible assets at least quarterly or whenever events or circumstances indicate that their carrying values may not be recoverable. If the indefinite-lived intangible asset carrying value exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. Estimating the fair value of indefinite-lived intangible assets involves the use of valuation techniques that rely on significant estimates and assumptions, including forecasted revenue growth rates, forecasted allocations of expense and risk-adjusted discount rates. Changes in these estimates and assumptions could materially affect the determination of fair value for indefinite-lived intangible assets. In certain circumstances, indefinite-lived intangible assets may be reviewed qualitatively for indications of impairment without utilizing valuation techniques to estimate fair value.
Business Combinations	Business Combinations.
Employee Benefit Plans	Employee Benefit Plans.
Foreign Currency Translation	Foreign Currency Translation and Re-measurement
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition. Revenue recognition policies for specific sources of revenue are discussed below. Clearing and Transaction Fees. Clearing and transaction fees include per-contract charges for trade execution, clearing, trading on the company's electronic trading platforms, portfolio reconciliation and compression services, risk mitigation, and other fees. Fees are charged at various rates based on the product traded, the method of trade, the exchange trading privileges of the customer making the trade and the type of contract. The majority of our clearing and transaction fees are recognized as revenue upon successful execution of the trade. Therefore, unfilled or canceled buy and sell orders have no impact on revenue. On occasion, the customer's exchange trading privileges may not be properly entered by the clearing firm and incorrect fees are charged for the transactions. When this information is corrected within the time period allowed by the company, a fee adjustment is provided to the clearing firm. A reserve is established for estimated fee adjustments to reflect corrections to customer exchange trading privileges. The reserve is based on the historical pattern of adjustments processed as well as management's estimate of future adjustment activity. The company believes the reserve is adequate to cover estimated adjustments as of December 31, 2023 and 2022. Market Data and Information Services. Market data and information services represent revenue earned for the dissemination of market information. Revenues are accrued each month based on the number of devices reported by vendors or over a straight line basis in accordance with the market data subscription contract term. The company conducts periodic examinations of the number of devices reported and assesses additional fees as necessary. On occasion, customers will pay for services in a lump sum payment; however, revenue is recognized as services are provided. Other Revenues. Other revenues include access and communication fees, fees for collateral management, equity membership subscription fees and fees for trade order routing through agreements from various strategic relationships as well as other services to customers. Revenue is recognized as services are provided. Concentration of Revenue. No clearing firms represented at least approximately 10% of the company's clearing and transaction fee revenue in 2023. One clearing firm represented at least approximately 10% of the company's clearing and transaction fee revenue in 2022 and 2021. Should a clearing firm withdraw from the company, management believes that the customer portion of that firm's trading activity would likely transfer to another clearing firm. Therefore, management does not believe that the company is exposed to significant risk from the ongoing loss of revenue received from a particular clearing firm.
Share-Based Payments	Share-Based Payments.
Marketing Costs	Marketing Costs.
Income Taxes	Income Taxes.
Segment Reporting	Segment Reporting.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue Recognition and Deferred Revenue [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table represents a disaggregation of revenue from contracts with customers for the years ended December 31, 2023, 2022 and 2021: (in millions) 2023 2022 2021 Interest rates $ 1,558.4 $ 1,326.8 $ 1,121.9 Equity indexes 1,036.4 1,016.3 752.1 Foreign exchange 190.0 188.3 159.2 Agricultural commodities 508.5 444.7 457.8 Energy 702.8 585.5 616.5 Metals 224.7 196.9 198.8 BrokerTec fixed income 152.1 164.7 172.0 EBS foreign exchange 132.6 154.1 164.3 Interest Rate Swap 83.0 65.4 62.6 Optimization — — 59.9 Total clearing and transaction fees 4,588.5 4,142.7 3,765.1 Market data 663.7 610.9 576.9 Other 326.7 265.8 347.7 Total revenues $ 5,578.9 $ 5,019.4 $ 4,689.7 Timing of Revenue Recognition Services transferred at a point in time 4,491.1 4,044.3 3,656.6 Services transferred over time 1,069.7 955.3 1,021.5 One-time charges and miscellaneous revenues 18.1 19.8 11.6 Total revenues $ 5,578.9 $ 5,019.4 $ 4,689.7

Performance Bonds and Guarant_2

Performance Bonds and Guaranty Fund Contributions (Tables)	12 Months Ended
	Dec. 31, 2023
Performance Bonds and Guaranty Fund Contributions [Abstract]
Cash and securities held as performance bonds and guaranty fund contributions at fair value	Cash and non-cash deposits held as performance bonds and guaranty fund contributions at fair value at December 31, 2023 and 2022 were as follows: 2023 2022 (in millions) Cash Non-Cash Deposits and IEF Funds (1) Cash Non-Cash Deposits and IEF Funds (1) Performance bonds $ 87,285.5 $ 180,866.3 $ 132,653.7 $ 94,127.2 Guaranty fund contributions 2,379.6 6,849.6 2,450.3 5,026.0 Cross-margin arrangements 183.1 1,374.5 142.6 561.1 Other (2) 344.3 2.1 2.6 2.1 Total $ 90,192.5 $ 189,092.5 $ 135,249.2 $ 99,716.4
Letters of credit	At December 31, 2023 and 2022, these letters of credit, which are not included in the accompanying consolidated balance sheets, were as follows: (in millions) 2023 2022 Performance bonds $ 3,916.7 $ 4,674.3 Performance bond collateral for delivery 4,631.4 3,445.0 Total Letters of Credit $ 8,548.1 $ 8,119.3

Property (Tables)

Property (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment, Net [Abstract]
Summary of the Property Accounts	A summary of the property accounts at December 31, 2023 and 2022 is presented below: (in millions) 2023 2022 Estimated Useful Life Building and building improvements $ 130.7 $ 132.2 1 - 10 years Leasehold improvements 143.7 224.8 3 - 19 years Furniture, fixtures and equipment 413.3 551.3 2 - 7 years Software and software development costs 654.9 692.4 2 - 4 years Total property 1,342.6 1,600.7 Less accumulated depreciation and amortization (933.1) (1,145.2) Property, net $ 409.5 $ 455.5

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Components of intangible assets	Intangible assets consisted of the following at December 31, 2023 and 2022: 2023 2022 (in millions) Assigned Value Accumulated Net Book Assigned Value Accumulated Net Book Amortizable Intangible Assets: Clearing firm, market data and other customer relationships $ 4,694.4 $ (2,124.9) $ 2,569.5 $ 4,685.8 $ (1,909.7) $ 2,776.1 Technology-related intellectual property 62.5 (62.2) 0.3 62.5 (55.8) 6.7 Other 71.6 (41.2) 30.4 69.5 (32.6) 36.9 Total Amortizable Intangible Assets $ 4,828.5 $ (2,228.3) $ 2,600.2 $ 4,817.8 $ (1,998.1) $ 2,819.7 Indefinite-Lived Intangible Assets: Trade names 450.0 450.0 Total Intangible Assets—Other, Net $ 3,050.2 $ 3,269.7 Trading products (1) $ 17,175.3 $ 17,175.3 _______________ (1) Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the CFTC. Product authorizations from the CFTC have no term limits.
Weighted average useful life for the amortizable intangible assets	The originally assigned useful lives for the amortizable intangible assets as of December 31, 2023 are as follows: Clearing firm, market data and other customer relationships 5 - 30 years Technology-related intellectual property 5 - 9 years Other 3 - 24.5 years
Future estimated amortization expense	As of December 31, 2023, the future estimated amortization expense related to amortizable intangible assets is expected to be as follows: (in millions) 2024 $ 222.2 2025 222.2 2026 222.2 2027 220.9 2028 214.5 Thereafter 1,498.2

Intangible Assets and Goodwil_2

Intangible Assets and Goodwill Goodwill (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill [Line Items]
Goodwill Disclosure [Text Block]	Goodwill activity consisted of the following for the years ended December 31, 2023 and 2022 : (in millions) Balance at December 31, 2022 Other Activity (1) Balance at December 31, 2023 CBOT Holdings $ 5,066.4 $ — $ 5,066.4 NYMEX Holdings 2,462.2 — 2,462.2 NEX 2,913.5 17.3 2,930.8 Other 40.4 (4.5) 35.9 Total Goodwill $ 10,482.5 $ 12.8 $ 10,495.3 (in millions) Balance at December 31, 2021 Other Activity (1) Balance at December 31, 2022 CBOT Holdings $ 5,066.4 $ — $ 5,066.4 NYMEX Holdings 2,462.2 — 2,462.2 NEX 2,959.0 (45.5) 2,913.5 Other 40.4 — 40.4 Total Goodwill $ 10,528.0 $ (45.5) $ 10,482.5 _______________

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Long-term Debt [Line Items]
Schedule of Long-term Debt	Long-term debt outstanding consisted of the following at December 31, 2023 and 2022 (in U.S. dollar equivalents): (in millions) 2023 2022 $750.0 million fixed rate notes due March 2025, stated rate of 3.00% (1) $ 749.1 $ 748.4 $500.0 million fixed rate notes due June 2028, stated rate of 3.75% 498.1 497.7 $750.0 million fixed rate notes due March 2032, stated rate of 2.65% 742.9 741.7 $750.0 million fixed rate notes due September 2043, stated rate of 5.30% (2) 744.0 743.7 $700.0 million fixed rate notes due June 2048, stated rate of 4.15% 691.3 690.9 Total long-term debt $ 3,425.4 $ 3,422.4 _______________ (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 3.11%. (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 4.73%.
Long-term debt maturities at par value	Short term and long-term debt maturities, at par value (in U.S. dollar equivalents), were as follows as of December 31, 2023: (in millions) Par Value 2024 $ — 2025 750.0 2026 — 2027 — 2028 500.0 Thereafter 2,200.0
Schedule of Short-term Debt [Table Text Block]	Short-term debt consisted of the following at December 31, 2023 and 2022 (in U.S. dollar equivalents): (in millions) 2023 2022 €15.0 million fixed rate notes due May 2023, stated rate of 4.30% $ — $ 16.0 Total short-term debt $ — $ 16.0

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Taxes on income	Income before income taxes and the income tax provision consisted of the following for the years ended December 31, 2023 and 2022 and 2021: (in millions) 2023 2022 2021 Income before income taxes: Domestic $ 3,900.5 $ 3,291.7 $ 2,728.5 Foreign 253.1 198.6 645.1 Total $ 4,153.6 $ 3,490.3 $ 3,373.6 Income tax provision: Current: Federal $ 751.7 $ 620.5 $ 509.2 State 205.8 177.1 173.7 Foreign 44.9 24.9 19.0 Total 1,002.4 822.5 701.9 Deferred: Federal 21.9 (16.3) (4.6) State (33.8) (7.3) 10.6 Foreign (63.1) 0.4 28.8 Total (75.0) (23.2) 34.8 Total Income Tax Provision $ 927.4 $ 799.3 $ 736.7
Reconciliation of the statutory U.S. federal income tax rate to the effective tax rate	Reconciliation of the U.S. federal income tax rate (statutory tax rate) to the effective tax rate is as follows: 2023 2022 2021 Statutory tax rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 3.3 3.9 4.3 Gain on formation of OSTTRA — — (2.5) Statutory rate change — — 1.1 Foreign-derived intangible income deduction (1.5) (1.5) (1.6) Other, net (0.5) (0.5) (0.5) Effective Tax Expense Benefit Rate 22.3 % 22.9 % 21.8 %
Deferred tax assets (liabilities)	At December 31, 2023 and 2022, deferred income tax assets (liabilities) consisted of the following: (in millions) 2023 2022 Deferred Income Tax Assets: Net operating losses $ 3.4 $ 3.7 Accrued expenses, compensation, leases and other 131.4 135.2 Subtotal 134.8 138.9 Valuation allowance (0.4) (0.4) Total deferred income tax assets 134.4 138.5 Deferred Income Tax Liabilities: Purchased intangible assets (5,298.2) (5,358.8) Other (115.4) (106.3) Property (1.3) (30.4) Total deferred income tax liabilities (5,414.9) (5,495.5) Net Deferred Income Tax Liabilities $ (5,280.5) $ (5,357.0) Reported as: Net non-current deferred tax assets $ 47.2 $ 4.1 Net non-current deferred tax liabilities (5,327.7) (5,361.1) Net Deferred Income Tax Liabilities $ (5,280.5) $ (5,357.0)
Unrecognized tax benefits	The following is a summary of the company’s unrecognized tax benefits at December 31, 2023, 2022 and 2021: (in millions) 2023 2022 2021 Gross unrecognized tax benefits $ 264.1 $ 280.3 $ 316.4 Unrecognized tax benefits, net of tax impacts in other jurisdictions 251.9 264.4 293.1 Interest and penalties related to uncertain tax positions 16.6 28.0 42.8 Interest and penalties recognized on the consolidated statements of income (4.0) (3.8) 5.3
Reconciliation of unrecognized tax benefits	A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits is as follows: (in millions) 2023 2022 2021 Balance at January 1 $ 280.3 $ 316.4 $ 328.2 Additions based on tax positions related to the current year 10.0 8.5 10.2 Additions for tax positions of prior years 4.3 2.7 9.6 Reductions for tax positions of prior years (8.0) (9.5) (5.1) Reductions resulting from the lapse of statutes of limitations (5.2) (5.5) (0.3) Settlements with taxing authorities (17.3) (32.3) (26.2) Balance at December 31 $ 264.1 $ 280.3 $ 316.4

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2023
Retirement Benefits, Description [Abstract]
Summary of the change in projected benefit obligation	The following is a summary of the change in projected benefit obligation: (in millions) 2023 2022 Balance at January 1 $ 316.4 $ 386.0 Service cost 21.1 25.7 Interest cost 18.5 12.0 Actuarial (gain) loss 18.3 (86.7) Benefits paid (22.8) (20.6) Balance at December 31 $ 351.5 $ 316.4
Change in plan assets	The following is a summary of the change in fair value of plan assets: (in millions) 2023 2022 2021 Balance at January 1 $ 331.7 $ 402.3 $ 388.2 Actual return on plan assets 38.9 (50.0) 34.0 Employer contributions 3.0 — — Benefits paid (22.8) (20.6) (19.9) Balance at December 31 $ 350.8 $ 331.7 $ 402.3
Fair value of plan assets	The fair value of each major category of plan assets as of December 31, 2023 and 2022 is indicated below: (in millions) 2023 2022 Level 2: Money market funds $ 6.2 $ 16.6 Mutual funds: Fixed income 165.3 131.6 U.S. equity 131.6 129.8 Foreign equity 47.7 53.7 Total $ 350.8 $ 331.7
Components of net pension expenses and the assumptions used to determine the end-of-year projected benefit obligation and net pension expense in aggregate	The components of net pension expense and the assumptions used to determine the end-of-year projected benefit obligation and net pension expense in aggregate at December 31, 2023 and 2022 and 2021 are indicated below: (in millions) 2023 2022 2021 Components of Net Pension Expense: Service cost $ 21.1 $ 25.7 $ 27.8 Interest cost 18.5 12.0 10.7 Expected return on plan assets (21.6) (22.3) (21.7) Recognized net actuarial loss 0.3 1.4 4.5 Net Pension Expense $ 18.3 $ 16.8 $ 21.3 Assumptions Used to Determine End-of-Year Benefit Obligation: Discount rate 5.20 % 5.60 % 3.00 % Rate of compensation increase 4.00 4.00 4.00 Cash balance interest crediting rate 5.14 4.75 4.00 Assumptions Used to Determine Net Pension Expense: Discount rate 5.60 % 3.00 % 2.70 % Rate of compensation increase 4.00 4.00 4.00 Expected return on plan assets 6.75 5.75 5.75 Interest crediting rate 4.75 4.00 4.00
Asset allocation for the plan	The asset allocation for the plan, by asset category, at December 31, 2023 and 2022 was as follows: 2023 2022 Fixed income 47.1 % 39.7 % Money market funds 1.8 5.0 U.S. equity 37.5 39.1 Foreign equity 13.6 16.2
Prior service costs and actuarial losses included in accumulated other comprehensive income (loss)	The pre-tax balance and activity of actuarial losses for the pension plan, which are included in other comprehensive income (loss), for 2023 are as follows: (in millions) Actuarial Balance at January 1 $ 32.2 Unrecognized net loss 1.1 Recognized as a component of net pension expense (0.3) Balance at December 31 $ 33.0
Anticipated benefit payments from the plan in future years	At December 31, 2023, anticipated benefit payments from the plan in future years are as follows: (in millions) 2024 $ 32.1 2025 32.5 2026 33.8 2027 34.5 2028 35.2 2029-2033 182.6

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Supplemental cash flow information related to leases was as follows for years ended December 31, 2023 and 2022: (in millions) 2023 2022 Cash outflows for operating leases $ 66.2 $ 65.4 Cash outflows for finance leases 17.2 17.1
Lease, Cost [Table Text Block]	The components of lease costs were as follows for the years ended December 31, 2023 and 2022: (in millions) 2023 2022 Operating lease expense: Operating lease cost $ 55.1 $ 56.9 Short-term lease cost 0.4 0.4 Total operating lease expense included in other expense $ 55.5 $ 57.3 Finance lease expense: Interest expense $ 2.5 $ 2.8 Depreciation expense 8.7 8.7 Total finance lease expense $ 11.2 $ 11.5 Sublease revenue included in other revenue $ 9.8 $ 10.6
Lessee, Operating Lease, Liability, Maturity	Future minimum lease payments were as follows as of December 31, 2023 for operating and finance leases: (in millions) Operating Leases 2024 $ 60.5 2025 57.4 2026 52.8 2027 50.3 2028 49.6 Thereafter 192.5 Total lease payments 463.1 Less: imputed interest (72.4) Present value of lease liability $ 390.7
Finance Lease, Liability, Fiscal Year Maturity	(in millions) Finance Lease 2024 $ 17.4 2025 17.5 2026 17.6 2027 17.8 2028 17.9 Thereafter 41.0 Total lease payments 129.2 Less: imputed interest (61.4) Present value of lease liability $ 67.8
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 as of December 31, 2023 and 2022: Operating leases (in millions) 2023 2022 Operating lease right-of-use assets $ 272.0 $ 310.6 Operating lease liabilities: Other current liabilities $ 46.7 $ 49.9 Other liabilities 344.0 383.5 Total operating lease liabilities $ 390.7 $ 433.4 Weighted average remaining lease term (in months) 114 121 Weighted average discount rate 3.8 % 3.8 %
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) 2023 2022 Finance lease right-of-use assets $ 62.8 $ 71.5 Finance lease liabilities: Other current liabilities $ 8.4 $ 8.2 Other liabilities 59.4 67.8 Total finance lease liabilities $ 67.8 $ 76.0 Weighted average remaining lease term (in months) 87 99 Weighted average discount rate 3.5 % 3.5 %

Capital Stock (Tables)

Capital Stock (Tables)	12 Months Ended
	Dec. 31, 2023
Capital Stock [abstract]
Capital stock	The following table presents information regarding capital stock: December 31, (in thousands) 2023 2022 Preferred stock authorized 10,000 10,000 Preferred stock issued and outstanding 4,584 4,584 Class A common stock authorized 1,000,000 1,000,000 Class A common stock issued and outstanding 359,231 358,929 Class B-1 common stock authorized, issued and outstanding 0.6 0.6 Class B-2 common stock authorized, issued and outstanding 0.8 0.8 Class B-3 common stock authorized, issued and outstanding 1.3 1.3 Class B-4 common stock authorized, issued and outstanding 0.4 0.4

Stock-Based Payments (Tables)

Stock-Based Payments (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Compensation expense for stock-based payments and total income tax benefit recognized	Total compensation expense for all stock-related awards (including ESPP) and total income tax benefit recognized on the consolidated statements of income for these awards at December 31, 2023 and 2022 and 2021 were as follows: (in millions) 2023 2022 2021 Compensation expense $ 83.7 $ 84.8 $ 76.4 Income tax benefit recognized 14.2 13.2 20.6
Schedule of Nonvested Share Activity [Table Text Block]	The following table summarizes restricted stock, restricted stock units and performance shares activity for 2023: Number of Shares Weighted Outstanding at December 31, 2022 1,117,459 $ 204 Granted 468,675 206 Vested (240,707) 190 Cancelled (245,547) 209 Outstanding at December 31, 2023 1,099,880 204

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	(in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2022 $ (0.9) $ (22.8) $ 64.7 $ (174.3) $ (133.3) Other comprehensive income before reclassifications and income tax benefit (expense) 0.6 (0.9) — 70.8 70.5 Reclassification adjustment for loss included in net income — — — 9.7 9.7 Amounts reclassified from accumulated other comprehensive income — 0.1 (3.6) — (3.5) Income tax benefit (expense) (0.1) 0.2 0.9 — 1.0 Net current period other comprehensive income 0.5 (0.6) (2.7) 80.5 77.7 Balance at December 31, 2023 $ (0.4) $ (23.4) $ 62.0 $ (93.8) $ (55.6) (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2021 $ 1.1 $ (34.8) $ 66.1 $ 21.1 $ 53.5 Other comprehensive income before reclassifications and income tax benefit (expense) (2.7) 14.9 — (195.4) (183.2) Amounts reclassified from accumulated other comprehensive income — 1.2 (1.9) — (0.7) Income tax benefit (expense) 0.7 (4.1) 0.5 — (2.9) Net current period other comprehensive income (2.0) 12.0 (1.4) (195.4) (186.8) Balance at December 31, 2022 $ (0.9) $ (22.8) $ 64.7 $ (174.3) $ (133.3) (in millions) Investment Securities Defined Benefit Plans Derivative Investments Foreign Currency Translation Total Balance at December 31, 2020 $ 1.6 $ (57.1) $ 67.0 $ 123.4 $ 134.9 Other comprehensive income before reclassifications and income tax benefit (expense) (1.0) 25.5 — (62.0) (37.5) Amounts reclassified from accumulated other comprehensive income 0.3 4.4 (1.2) (40.3) (36.8) Income tax benefit (expense) 0.2 (7.6) 0.3 — (7.1) Net current period other comprehensive income (0.5) 22.3 (0.9) (102.3) (81.4) Balance at December 31, 2021 $ 1.1 $ (34.8) $ 66.1 $ 21.1 $ 53.5

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Financial instruments measured at fair value on a recurring basis	December 31, 2023 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 10.2 $ — $ — $ 10.2 Mutual funds 101.3 — — 101.3 Equity securities 0.2 — — 0.2 Total Marketable Securities 111.7 — — 111.7 Total Assets at Fair Value $ 111.7 $ — $ — $ 111.7 December 31, 2022 (in millions) Level 1 Level 2 Level 3 Total Assets at Fair Value: Marketable securities: Corporate debt securities $ 11.3 $ — $ — $ 11.3 Mutual funds 84.5 — — 84.5 Equity securities 0.2 — — 0.2 Total Marketable Securities 96.0 — — 96.0 Total Assets at Fair Value $ 96.0 $ — $ — $ 96.0
Fair value of Debt Instruments [Table Text Block]	At December 31, 2023, the fair values (in U.S. dollar equivalents) were as follows: (in millions) Fair Value Level $750.0 million fixed rate notes due March 2025 733.8 Level 2 $500.0 million fixed rate notes due June 2028 489.3 Level 2 $750.0 million fixed rate notes due March 2032 669.0 Level 2 $750.0 million fixed rate notes due September 2043 802.2 Level 2 $700.0 million fixed rate notes due June 2048 641.0 Level 2

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Anti-dilutive stock awards were as follows for the years presented: (in thousands) 2023 2022 2021 Stock awards 455 158 86 Total 455 158 86
Basic and diluted earnings per share	The following table presents the earnings per share calculation for the years presented: 2023 2022 2021 Net Income Attributable to CME Group (in millions) $ 3,226.2 $ 2,691.0 $ 2,636.4 Less: Preferred stock dividends (44.2) (38.9) (19.0) Less: (Undistributed earnings) overdistributed earnings allocated to preferred stock 3.6 5.1 (0.3) Net Income Attributable to Common Shareholders of CME Group $ 3,185.6 $ 2,657.2 $ 2,617.1 Weighted Average Common Shares Outstanding (in thousands): Basic 359,023 358,713 358,340 Effect of stock options and stock awards 477 468 589 Diluted 359,500 359,181 358,929 Earnings per Common Share Attributable to Common Shareholders of CME Group: Basic $ 8.87 $ 7.41 $ 7.30 Diluted 8.86 7.40 7.29

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Clearing and Transaction Fees [Member] | Clearing and Transaction Fees [Member] | Clearing and Transaction Fees [Member]
Concentration of revenue	10%
Sales Revenue, Market Data and Information Services [Member] | Sales Revenue, Market Data and Information Services [Member] | Sales Revenue, Market Data and Information Services [Member]
Concentration of revenue	32%	33%	34%
Minimum [Member]
Estimated useful live of the assets minimum in years	2 years
Minimum [Member] | Software and software development costs
Estimated useful live of the assets minimum in years	2 years
Maximum [Member]
Estimated useful live of the assets minimum in years	20 years
Maximum [Member] | Software and software development costs
Estimated useful live of the assets minimum in years	4 years

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Total Revenues	$ 5,578.9	$ 5,019.4	$ 4,689.7
Clearing and Transaction Fees [Member]
Revenue	4,588.5	4,142.7	3,765.1
Total Revenues	4,588.5	4,142.7	3,765.1
MarketData [Member]
Revenue	663.7	610.9	576.9
Total Revenues	663.7	610.9	576.9
OtherRevenue [Member]
Revenue	326.7	265.8	347.7
Total Revenues	326.7	265.8	347.7
Interest Rate [Member] | Clearing and Transaction Fees [Member]
Revenue	1,558.4	1,326.8	1,121.9
Equities [Member] | Clearing and Transaction Fees [Member]
Revenue	1,036.4	1,016.3	752.1
Foreign Exchange [Member] | Clearing and Transaction Fees [Member]
Revenue	190	188.3	159.2
Agricultural commodity [Member] | Clearing and Transaction Fees [Member]
Revenue	508.5	444.7	457.8
Energy [Member] | Clearing and Transaction Fees [Member]
Revenue	702.8	585.5	616.5
Metal [Member] | Clearing and Transaction Fees [Member]
Revenue	224.7	196.9	198.8
Over the Counter [Member] | Clearing and Transaction Fees [Member]
Revenue	83	65.4	62.6
BrokerTec Fixed Income | Clearing and Transaction Fees [Member]
Revenue	152.1	164.7	172
EBS Foreign Exchange | Clearing and Transaction Fees [Member]
Revenue	132.6	154.1	164.3
Optimization | Clearing and Transaction Fees [Member]
Revenue	0	0	59.9
Transferred at Point in Time [Member]
Revenue	4,491.1	4,044.3	3,656.6
Transferred over Time [Member]
Revenue	1,069.7	955.3	1,021.5
One-time charges and miscellaneous revenues [Member]
Revenue	$ 18.1	$ 19.8	$ 11.6

Performance Bonds and Guarant_3

Performance Bonds and Guaranty Fund Contributions (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) days	Dec. 31, 2022 USD ($)
Percentage share of cross-margining collateral	50%
Line of Credit, Guaranty Fund Collateral Available	$ 8,600
Days fully secured | days	364
Intraday settlements of cash performance bonds	$ 237.5	$ 436.7
Average daily clearing settlement	5,900
364-day fully secured, committed line of credit
Line of Credit Facility, Maximum Borrowing Capacity	7,000
Option on increase in line of credit	10,000
Revolving senior credit facility
Line of Credit Facility, Maximum Borrowing Capacity	2,300
CME Base Guaranty Fund [Member]
Corporate Contribution	100
CME IRS Guaranty Fund [Member] [Member]
Corporate Contribution	150
Federal Reserve Reinvestment [Member]
Cash Equivalents, at Carrying Value	$ 79,300	$ 124,900

Performance Bonds and Guarant_4

Performance Bonds and Guaranty Fund Contributions (Cash and Securities Held as Performance Bonds and Guaranty Fund Contributions at Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Total	$ 90,192.5	$ 135,249.2	$ 157,949.6
Cash [Member]
Performance bonds	87,285.5	132,653.7
Guaranty Fund Contributions	2,379.6	2,450.3
Cross-margin arrangements	183.1	142.6
Performance collateral for delivery	344.3	2.6
Total	90,192.5	135,249.2
Non-Cash Deposits and IEF Funds [Member]
Performance bonds	180,866.3	94,127.2
Guaranty Fund Contributions	6,849.6	5,026
Cross-margin arrangements	1,374.5	561.1
Performance collateral for delivery	2.1	2.1
Total	$ 189,092.5	$ 99,716.4

Performance Bonds and Guarant_5

Performance Bonds and Guaranty Fund Contributions (Performance Bond Deposits and Security Deposits) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Letters of Credit Outstanding, Amount	$ 8,548.1	$ 8,119.3
Performance Bond [Member]
Letters of Credit Outstanding, Amount	3,916.7	4,674.3
Delivery [Member]
Letters of Credit Outstanding, Amount	$ 4,631.4	$ 3,445

Property (Details)

Property (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, gross	$ 1,342.6	$ 1,600.7
Less accumulated depreciation and amortization	(933.1)	(1,145.2)
Property, net	409.5	455.5
Software and software development costs
Property, Plant and Equipment [Line Items]
Property, gross	654.9	692.4
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property, gross	413.3	551.3
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, gross	143.7	224.8
Building and building improvements
Property, Plant and Equipment [Line Items]
Property, gross	$ 130.7	$ 132.2
Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	2 years
Minimum [Member] | Software and software development costs
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	2 years
Minimum [Member] | Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	2 years
Minimum [Member] | Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	3 years
Minimum [Member] | Building and building improvements
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	1 year
Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	20 years
Maximum [Member] | Software and software development costs
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	4 years
Maximum [Member] | Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	7 years
Maximum [Member] | Leasehold improvements
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	19 years
Maximum [Member] | Building and building improvements
Property, Plant and Equipment [Line Items]
Estimated useful life, minimum	10 years

Intangible Assets and Goodwil_3

Intangible Assets and Goodwill (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Intangible assets—other, net	$ 3,050.2	$ 3,269.7
Amortization of purchased intangibles	$ 226.6	$ 227.7	$ 237.6

Intangible Assets and Goodwil_4

Intangible Assets and Goodwill (Components of Intangible Assets) (Details) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Net book value		$ 3,050.2	$ 3,269.7
Other Indefinite-lived Intangible Assets	[1]	17,175.3	17,175.3
Trade Names [Member]
Net book value		450	450
Clearing Firm, Market Data, and Other Customer Relationships [Member]
Cost		4,694.4	4,685.8
Accumulated amortization		(2,124.9)	(1,909.7)
Net book value		2,569.5	2,776.1
Technology-Related Intellectual Property [Member]
Cost		62.5	62.5
Accumulated amortization		(62.2)	(55.8)
Net book value		0.3	6.7
Other Intangible Assets [Member]
Cost		71.6	69.5
Accumulated amortization		(41.2)	(32.6)
Net book value		30.4	36.9
Finite-Lived Intangible Assets [Member]
Cost		4,828.5	4,817.8
Accumulated amortization		(2,228.3)	(1,998.1)
Net book value		$ 2,600.2	$ 2,819.7
[1] Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the CFTC. Product authorizations from the CFTC have no term limits.

Intangible Assets and Goodwil_5

Intangible Assets and Goodwill Intangible Assets and Goodwill (Useful Lives of Intangible Assets) (Details)	Dec. 31, 2023
Minimum [Member] | Clearing Firm, Market Data, and Other Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, minimum	5 years
Minimum [Member] | Technology-Related Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, minimum	5 years
Minimum [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, minimum	3 years
Maximum [Member] | Clearing Firm, Market Data, and Other Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, minimum	30 years
Maximum [Member] | Technology-Related Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, minimum	9 years
Maximum [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, minimum	24 years 6 months

Intangible Assets and Goodwil_6

Intangible Assets and Goodwill (Future Estimated Amortization Expense) (Details) $ in Millions	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2021	$ 222.2
2022	222.2
2023	222.2
2024	220.9
2025	214.5
Thereafter	$ 1,498.2

Intangible Assets and Goodwil_7

Intangible Assets and Goodwill Intangible Assets and Goodwill (Components of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 10,495.3	$ 10,482.5
CBOT [Member]
Goodwill [Line Items]
Goodwill	5,066.4	5,066.4	$ 5,066.4
Goodwill, Other Increase (Decrease)	0	0
NYMEX [Member]
Goodwill [Line Items]
Goodwill	2,462.2	2,462.2	2,462.2
Goodwill, Other Increase (Decrease)	0	0
NEX [Member]
Goodwill [Line Items]
Goodwill	2,930.8	2,913.5	2,959
Goodwill, Other Increase (Decrease)	17.3	(45.5)
Other CME Segments
Goodwill [Line Items]
Goodwill	35.9	40.4	40.4
Goodwill, Other Increase (Decrease)	(4.5)	0
CME Group Inc.
Goodwill [Line Items]
Goodwill	10,495.3	10,482.5	$ 10,528
Goodwill, Other Increase (Decrease)	$ 12.8	$ (45.5)

Long-Term Investments (Details)

Long-Term Investments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Gain (Loss) on Investments	$ 72,100,000	$ 4,800,000	$ 117,000,000
Net cash proceeds from OSTTRA joint venture transaction	0	0	100,700,000
Gain on joint venture	$ 0	$ 0	$ 400,700,000
DME Holdings [Member]
Equity Method Investment, Ownership Percentage	50%
Equity Method Investments	$ 13,800,000
OSSTRA
Equity Method Investment, Ownership Percentage	50%
Equity Method Investments	$ 1,300,000,000
Net cash proceeds from OSTTRA joint venture transaction	112,500,000
Gain on joint venture	$ 400,700,000
S&P/DJI [Member]
Equity Method Investment, Ownership Percentage	27%
Equity Method Investments	$ 1,400,000,000
Payments to Acquire Investments	$ 410,000,000
CFETS
Equity Method Investment, Ownership Percentage	33%
Equity Method Investments	$ 51,300,000

Debt (Schedule of Short-Term an

Debt (Schedule of Short-Term and Long-Term Debt) (Details) € in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022 USD ($)
Long-term Debt
Long-term debt		$ 3,425.4		$ 3,422.4
Short-term debt		0		16
$750.0 million Fixed Rate Notes Due September 2022 Interest Equal To 3.00% [Member]
Long-term Debt
Debt instrument, face amount		$ 750
Debt Instrument, maturity date		Sep. 01, 2022
Debt Instrument, Interest Rate, Stated Percentage		3%	3%
€15.0 million fixed rate notes due May 2023 [Member]
Long-term Debt
Debt instrument, face amount | €			€ 15
Debt Instrument, maturity date		May 31, 2023
Debt Instrument, Interest Rate, Stated Percentage		4.30%	4.30%
Short-term debt		$ 0		16
$750.0 Million Fixed Rate Notes Due March 2025, Interest Equal To 3.00% [Member]
Long-term Debt
Long-term debt	[1]	749.1		748.4
Debt instrument, face amount		$ 750
Debt Instrument, maturity date		Mar. 01, 2025
Debt Instrument, Interest Rate, Stated Percentage		3%	3%
Debt Instrument, Interest Rate During Period		3.11%
$500.0 Million Fixed Rate Notes Due June 2028, Interest Equal To 3.75% [Member] [Domain]
Long-term Debt
Long-term debt		$ 498.1		497.7
Debt instrument, face amount		$ 500
Debt Instrument, maturity date		Jun. 15, 2028
Debt Instrument, Interest Rate, Stated Percentage		3.75%	3.75%
$750.0 million Fixed Rate Notes Due September 2043 Interest Equal To 5.3% [Member]
Long-term Debt
Long-term debt	[2]	$ 744		743.7
Debt instrument, face amount		$ 750
Debt Instrument, maturity date		Sep. 01, 2043
Debt Instrument, Interest Rate, Stated Percentage		5.30%	5.30%
Debt Instrument, Interest Rate During Period		4.73%
$700.0 Million Fixed Rate Notes Due June 2048, Interest Equal To 4.15% [Member] [Domain] [Domain]
Long-term Debt
Long-term debt		$ 691.3		690.9
Debt instrument, face amount		$ 700
Debt Instrument, maturity date		Jun. 15, 2048
Debt Instrument, Interest Rate, Stated Percentage		4.15%	4.15%
$750.0 Million Fixed Rate Notes Due March 2032, Interest Equal To 2.65%
Long-term Debt
Long-term debt		$ 742.9		$ 741.7
Debt instrument, face amount		$ 750
Debt Instrument, maturity date		Mar. 31, 2032
Debt Instrument, Interest Rate, Stated Percentage		2.65%	2.65%
[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 3.11%.

Debt (Long-Term Debt Maturities

Debt (Long-Term Debt Maturities at Par Value) (Details) $ in Millions	Dec. 31, 2023 USD ($)
Debt Disclosure [Abstract]
2021	$ 0
2022	750
2023	0
2024	0
2025	500
Thereafter	$ 2,200

Income Taxes (Income Tax Provis

Income Taxes (Income Tax Provision) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income before income taxes: Domestic	$ 3,900.5	$ 3,291.7	$ 2,728.5
Income before income taxes: Foreign	253.1	198.6	645.1
Income from before income taxes	4,153.6	3,490.3	3,373.6
Current income tax provision: Federal	751.7	620.5	509.2
Current income tax provision: State	205.8	177.1	173.7
Current income tax provision: Foreign	44.9	24.9	19
Current income tax provision: Total	1,002.4	822.5	701.9
Deferred income tax provision: Federal	21.9	(16.3)	(4.6)
Deferred income tax provision: State	(33.8)	(7.3)	10.6
Deferred income tax provision: Foreign	(63.1)	0.4	28.8
Deferred income tax provision: Total	(75)	(23.2)	34.8
Total Income Tax Provision	$ 927.4	$ 799.3	$ 736.7

Income Taxes (Federal Income Ta

Income Taxes (Federal Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Statutory U.S. federal tax rate	21%	21%	21%
State taxes, net of federal benefit	3.30%	3.90%	4.30%
Effective Income Tax Rate Reconciliation, Disposition of Business, Percent	0%	0%	(2.50%)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	0%	0%	1.10%
Effective Tax Rate Reconciliation, Foreign Derived Intangible Income Deduction	1.50%	1.50%	1.60%
Other, net	(0.50%)	(0.50%)	(0.50%)
Effective Tax Rate	22.30%	22.90%	21.80%

Income Taxes (Deferred Tax Asse

Income Taxes (Deferred Tax Assets (Liabilities) ) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Net operating losses	$ 3.4	$ 3.7
Accrued expenses, compensation, leases and other	131.4	135.2
Subtotal	134.8	138.9
Valuation allowance	(0.4)	(0.4)
Total deferred tax assets	134.4	138.5
Purchase intangible assets	(5,298.2)	(5,358.8)
Other	(115.4)	(106.3)
Property	(1.3)	(30.4)
Total deferred income tax liabilities	(5,414.9)	(5,495.5)
Deferred income tax liabilities, net	5,280.5	5,357
Net non-current deferred tax assets	$ 47.2	$ 4.1

Income Taxes (Summary Of Unreco

Income Taxes (Summary Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits	$ 264.1	$ 280.3	$ 316.4	$ 328.2
Unrecognized tax benefits, net of tax impacts in other jurisdictions	251.9	264.4	293.1
Interest and penalties related to uncertain tax positions	16.6	28	42.8
Interest and penalties recognized in the consolidated statements of income	$ (4)	$ (3.8)	$ 5.3

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance as of January 1	$ 280.3	$ 316.4	$ 328.2
Additions based on tax positions related to the current year	10	8.5	10.2
Additions for tax positions of prior years	4.3	2.7	9.6
Reductions for tax positions of prior years	(8)	(9.5)	(5.1)
Reductions resulting from the lapse of statutes of limitations	(5.2)	(5.5)	(0.3)
Settlements with taxing authorities	(17.3)	(32.3)	(26.2)
Balance as of December 31	$ 264.1	$ 280.3	$ 316.4

Income Taxes Income Taxes (Narr

Income Taxes Income Taxes (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards	$ 16	$ 17.6
Deferred Tax Assets, Valuation Allowance	0.4	0.4
Net non-current deferred tax assets	$ 47.2	$ 4.1

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Defined Contribution Plan, Cost	$ 19,700,000	$ 18,300,000	$ 24,700,000
Trading securities fair value	101,300,000	$ 84,500,000
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 16,900,000
Pension Plan [Member]
Age for participation eligibility in benefit plan	21
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Cash Balance Interest Crediting Rate	4.75%	4%	4%
Years of service for vesting eligibility	3 years
Accumulated benefit obligation	$ 323,200,000	$ 294,400,000
Excess of pension plan assets over the projected benefit obligation	$ 700,000	(15,300,000)
Percentage of employees base salary matched by employer, maximum	3%
Defined Benefit Plan Funding Goal Percentage	100%
Defined Benefit Plan Funding Goal Percentage	100%
Pension Plan [Member] | Fixed Income Funds [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50%
Pension Plan [Member] | US Equity [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	50%
Other Postretirement Benefits Plan [Member]
Fair value of assets	$ 10,800,000	12,000,000
Total obligation	$ 8,700,000	$ 10,300,000

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary of the change in projected benefit obligation) (Details) - Pension Plans [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at January 1	$ 316.4	$ 386
Service cost	21.1	25.7	$ 27.8
Interest cost	18.5	12	10.7
Actuarial (gain) loss	18.3	(86.7)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(22.8)	(20.6)
Balance at December 31	351.5	316.4	386
Employer contributions	$ 3	$ 0	$ 0

Employee Benefit Plans (Change

Employee Benefit Plans (Change in Plan Assets) (Details) - Pension Plans [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance at January 1	$ 331.7	$ 402.3	$ 388.2
Actual return on plan assets	38.9	(50)	34
Defined Benefit Plan, Plan Assets, Benefits Paid	(22.8)	(20.6)	(19.9)
Balance at December 31	$ 350.8	$ 331.7	$ 402.3

Employee Benefit Plans (Fair Va

Employee Benefit Plans (Fair Value of Plan Assets) (Details) - Pension Plans [Member] - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Plan Assets, Amount	$ 350.8	$ 331.7	$ 402.3	$ 388.2
Defined Benefit Plan, Cash [Member]
Actual allocation of plan assets, Fixed income	1.80%	5%
Fixed Income Funds [Member]
Actual allocation of plan assets, Fixed income	47.10%	39.70%
US Equity [Member]
Actual allocation of plan assets, Fixed income	37.50%	39.10%
Foreign equity [Member]
Actual allocation of plan assets, Fixed income	13.60%	16.20%
Fair Value, Inputs, level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount	$ 350.8	$ 331.7
Fair Value, Inputs, level 2 [Member] | Defined Benefit Plan, Cash [Member]
Defined Benefit Plan, Plan Assets, Amount	6.2	16.6
Fair Value, Inputs, level 2 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan, Plan Assets, Amount	165.3	131.6
Fair Value, Inputs, level 2 [Member] | US Equity [Member]
Defined Benefit Plan, Plan Assets, Amount	131.6	129.8
Fair Value, Inputs, level 2 [Member] | Foreign equity [Member]
Defined Benefit Plan, Plan Assets, Amount	$ 47.7	$ 53.7

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Pension Expense) (Details) - Pension Plans [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of Net Pension Expense:
Service cost	$ 21.1	$ 25.7	$ 27.8
Interest cost	18.5	12	10.7
Expected return on plan assets	(21.6)	(22.3)	(21.7)
Recognized net actuarial loss	0.3	1.4	4.5
Net Pension Expense	$ 18.3	$ 16.8	$ 21.3
Assumptions Used to Determine End-of-Year Benefit Obligation:
Discount rate	5.20%	5.60%	3%
Rate of compensation increase	4%	4%	4%
Cash balance interest crediting rate	5.14%	4.75%	4%
Assumptions Used to Determine Net Pension Expense:
Discount rate	5.60%	3%	2.70%
Rate of compensation increase	4%	4%	4%
Expected return on plan assets	6.75%	5.75%	5.75%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Cash Balance Interest Crediting Rate	4.75%	4%	4%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Weighted-Average Interest Crediting Rate	4%

Employee Benefit Plans (Accumul

Employee Benefit Plans (Accumulated Other Comprehensive Income (Loss), of the Prior Service Costs and Actuarial Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Actuarial Losses [Roll Forward]
Net change in defined benefit plans arising during the period	$ (0.9)	$ 14.9	$ 25.5
Amortization of net actuarial (gains) losses and prior service costs included in compensation and benefits expense	0.1	1.2	$ 4.4
Pension Plans [Member]
Actuarial Losses [Roll Forward]
Actuarial Loss Beginning Balance	32.2
Net change in defined benefit plans arising during the period	1.1
Amortization of net actuarial (gains) losses and prior service costs included in compensation and benefits expense	(0.3)
Actuarial Loss Ending Balance	$ 33	$ 32.2

Employee Benefit Plans (Anticip

Employee Benefit Plans (Anticipated Benefit Payments from the Plan in Future Years) (Details) - Pension Plans [Member] $ in Millions	Dec. 31, 2023 USD ($)
2021	$ 32.1
2022	32.5
2023	33.8
2024	34.5
2025	35.2
2026-2030	$ 182.6

Leases and Other Commitments (N

Leases and Other Commitments (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Operating Lease, Cost	$ 55.1	$ 56.9
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
Short-term Lease, Cost	$ 0.4	0.4
Operating Lease, Expense	55.5	57.3
Finance Lease, Interest Expense	2.5	2.8
Finance Lease, Right-of-Use Asset, Amortization	8.7	8.7
Finance Lease, Expense	11.2	11.5
Sublease Income	$ 9.8	$ 10.6

Leases and Other Commitments Le

Leases and Other Commitments Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease Costs [Abstract]
Operating Lease, Cost	$ 55.1	$ 56.9
Short-term Lease, Cost	0.4	0.4
Operating Lease, Expense	55.5	57.3
Finance Lease, Interest Expense	2.5	2.8
Finance Lease, Right-of-Use Asset, Amortization	8.7	8.7
Finance Lease, Expense	11.2	11.5
Sublease Income	$ 9.8	$ 10.6

Leases and Other Commitments Su

Leases and Other Commitments Supplemental Cash Flow Information-Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease Costs [Abstract]
Operating Lease, Payments	$ 66.2	$ 65.4
Finance Lease, Principal Payments	$ 17.2	$ 17.1

Leases and Other Commitments _2

Leases and Other Commitments Supplemental Balance Sheet Information-Leases (Details)	Dec. 31, 2023	Dec. 31, 2022
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Operating Lease, Weighted Average Remaining Lease Term	114 months	121 months
Operating Lease, Weighted Average Discount Rate, Percent	3.80%	3.80%
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Finance Lease, Weighted Average Remaining Lease Term	87 months	99 months
Finance Lease, Weighted Average Discount Rate, Percent	3.50%	3.50%
Other Current Liabilities
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities
Other Noncurrent Liabilities
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities	Other Liabilities
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities	Other Liabilities
Liability
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Liabilities	Liabilities
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities	Liabilities

Leases and Other Commitments Op

Leases and Other Commitments Operating Leases Future Minimum Payments Due (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
2024	$ 60.5
2025	57.4
2026	52.8
2027	50.3
2028	49.6
Thereafter	192.5
Liability
Total Operating Lease Payments	463.1
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	$ (72.4)
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Liabilities	Liabilities

Leases and Other Commitments Ca

Leases and Other Commitments Capital Lease Future Minimum Payments (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
2024	$ 17.4
2025	17.5
2026	17.6
2027	17.8
2028	17.9
Thereafter	41
Liability
Total Capital Lease Payments	129.2
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	72.4
Finance Lease, Liability, Undiscounted Excess Amount	$ (61.4)
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities	Liabilities

Guarantees (Details)

Guarantees (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)
Guarantor Obligations [Line Items]
PaymentPerParticipant	$ 25,000
Contingent liability to SGX, amount of irrevocable letters of credit	285,000,000
PaymentPerCooperative	100,000
Guarantor Obligations, Maximum Exposure, Undiscounted	100,000,000
Line of Credit Facility, Commitment Fee Amount	350,000,000
Family Farmer and Ranchers Protection Fund [Member]
Guarantor Obligations [Line Items]
Payments under Guarantee	2,000,000
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 98,000,000

Capital Stock (Narrative) (Deta

Capital Stock (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023 directors $ / shares shares	Dec. 31, 2022 $ / shares
Number of directors | directors	23
Preferred Stock, Shares Issued	4,600,000
Class A Common Stock (Shares) [Member]
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Class B Common Stock (Shares)
Common Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Class B Common Stock, Class B1 [Member]
Number of directors	3
Class B Common Stock, Class B2 [Member]
Number of directors	2
Class B Common Stock, Class B3 [Member]
Number of directors	1
Class B common stock, Class B1, B2, B3 [Member]
Number of directors	6
CME Group Omnibus Stock Plan [Member]
Number of shares reserved for awards under the plan	40,200,000
Director Stock Plan; Class A Shares [Member]
Number of shares reserved for awards under the plan	725,000
Employee Stock Purchase Plan; Class A Shares [Member]
Number of shares reserved for awards under the plan	800,000
Market value of the shares an Employee Stock Purchase Plan	90%
Class A shares Purchased under Employee Stock Purchase Plan	473,101

Capital Stock (Capital stock) (

Capital Stock (Capital stock) (Details) - shares	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,099,880	1,117,459
Class A Common Stock
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Outstanding	359,231,000	358,929,000	358,599,000	358,110,000
Class B Common Stock, Class B1 [Member]
Common Stock, Shares, Outstanding	600	600
Class B Common Stock, Class B2 [Member]
Common Stock, Shares, Outstanding	800	800
Class B Common Stock, Class B3 [Member]
Common Stock, Shares, Outstanding	1,300	1,300
Class B Common Stock, Class B4 [Member]
Common Stock, Shares, Outstanding	400	400
Convertible Preferred Stock
Common Stock, Shares, Outstanding	4,584,000	4,584,000	4,584,000	0
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Outstanding	4,584,000	4,584,000
CME Group Omnibus Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	25,600,000
Director Stock Plan; Class A Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	469,322

Stock-Based Payments (Narrative

Stock-Based Payments (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number		1,099,880	1,117,459
Vesting percentage after one year		25%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized		$ 131,100,000
Employee service share-based compensation, unrecognized compensation costs on nonvested awards, Weighted Average Period of Recognition, years		2 years 2 months 12 days
Granted performance shares		468,675
Restricted Class A common stock, fair value		$ 49,600,000	$ 52,200,000	$ 65,700,000
Total expense for stock payments		$ 83,700,000	$ 84,800,000	$ 76,400,000
Share-based compensation arrangement by share-based payment award, discount from market price		90%
Class A common stock issued to participating employees		40,960	41,722	37,861
Director Stock Plan; Class A Shares [Member]
Total expense for stock payments		$ 3,600,000	$ 3,600,000	$ 2,900,000
Annual award of class A common stock value	$ 145,000
Annual stipend allowance in shares of stock	$ 95,000
Annual stipend allowance in shares of stock (in shares)		19,966	18,836	13,769
Employee Stock Purchase Plan; Class A Shares [Member]
Total expense for stock payments		$ 800,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		2 years
Class A Common Stock (Shares) [Member]
Stock options, granted, shares		370,024
Restricted Class A common stock, fair value		$ 78,400,000
Performance Shares [Member]
Granted performance shares		84,397
Restricted Class A common stock, fair value		$ 19,000,000
Restricted Stock Units (RSUs) [Member]
Stock options, granted, shares		10,774
CME Group Omnibus Stock Plan [Member]
Share-based compensation arrangement by share-based payment award, number of shares reserved		40,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number		25,600,000

Stock-Based Payments (Compensat

Stock-Based Payments (Compensation Expense And Income Tax Benefit Recognized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 83.7	$ 84.8	$ 76.4
Income tax benefit recognized	$ 14.2	$ 13.2	$ 20.6

Stock-Based Payments (Restricte

Stock-Based Payments (Restricted Stock Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares outstanding at December 31 (shares)	1,117,459
Number of shares granted	468,675
Number of shares vested	(240,707)
Number of shares cancelled	(245,547)
Number of shares outstanding at December 31 (shares)	1,099,880
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Weighted average grant date fair value outstanding	$ 204	$ 204
Weighted average grant date fair value granted	206
Weighted average grant date fair value vested	190
Weighted average grant date fair value cancelled	$ 209

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	$ 26,878.7
Other comprehensive income/(loss)	77.7	$ (186.8)	$ (81.4)
Total CME Group Shareholders' Equity, ending	26,737.9	26,878.7
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	(133.3)	53.5	134.9
Other comprehensive income/(loss)	77.7	(186.8)	(81.4)
Total CME Group Shareholders' Equity, ending	(55.6)	(133.3)	53.5
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	(133.3)	53.5	134.9
Comprehensive Income Before Reclassification Adjustments	70.5	(183.2)	(37.5)
Comprehensive Income Reclassification Adjustments	(3.5)	(0.7)	(36.8)
Income tax benefit (expense)	1	(2.9)	(7.1)
Other comprehensive income/(loss)	77.7	(186.8)	(81.4)
Total CME Group Shareholders' Equity, ending	(55.6)	(133.3)	53.5
Foreign Currency Gain (Loss) [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	(174.3)	21.1	123.4
Comprehensive Income Before Reclassification Adjustments	70.8	(195.4)	(62)
Comprehensive Income Reclassification Adjustments	0	0	(40.3)
Income tax benefit (expense)	0	0	0
Other comprehensive income/(loss)	80.5	(195.4)	(102.3)
Total CME Group Shareholders' Equity, ending	(93.8)	(174.3)	21.1
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	64.7	66.1	67
Comprehensive Income Before Reclassification Adjustments	0	0	0
Comprehensive Income Reclassification Adjustments	(3.6)	(1.9)	(1.2)
Income tax benefit (expense)	0.9	0.5	0.3
Other comprehensive income/(loss)	(2.7)	(1.4)	(0.9)
Total CME Group Shareholders' Equity, ending	62	64.7	66.1
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	(22.8)	(34.8)	(57.1)
Comprehensive Income Before Reclassification Adjustments	(0.9)	14.9	25.5
Comprehensive Income Reclassification Adjustments	0.1	1.2	4.4
Income tax benefit (expense)	0.2	(4.1)	(7.6)
Other comprehensive income/(loss)	(0.6)	12	22.3
Total CME Group Shareholders' Equity, ending	(23.4)	(22.8)	(34.8)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Total CME Group Shareholders' Equity, beginning	(0.9)	1.1	1.6
Comprehensive Income Before Reclassification Adjustments	0.6	(2.7)	(1)
Comprehensive Income Reclassification Adjustments	0	0	0.3
Income tax benefit (expense)	(0.1)	0.7	0.2
Other comprehensive income/(loss)	0.5	(2)	(0.5)
Total CME Group Shareholders' Equity, ending	$ (0.4)	$ (0.9)	$ 1.1

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading Securities at Fair Value	$ 101.3	$ 84.5
Investments, Fair Value Disclosure	8.6
Fair Value, Measurements, Recurring [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	111.7	96
Total Assets at Fair Value	111.7	96
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 1 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	111.7	96
Total Assets at Fair Value	111.7	96
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 2 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0	0
Total Assets at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0	0
Total Assets at Fair Value	0	0
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	10.2	11.3
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 1 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	10.2	11.3
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 2 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	0	0
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	0	0
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading Securities at Fair Value	101.3	84.5
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 1 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading Securities at Fair Value	101.3	84.5
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 2 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading Securities at Fair Value	0	0
Mutual Fund [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading Securities at Fair Value	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	0.2	0.2
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 1 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	0.2	0.2
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 2 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	0	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable Securities	$ 0	$ 0

Fair Value Measurements (Debt I

Fair Value Measurements (Debt Instruments) (Details) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Long-term debt		$ 3,425.4	$ 3,422.4
$750.0 Million Fixed Rate Notes Due March 2025, Interest Equal To 3.00% [Member]
Long-term debt	[1]	749.1	748.4
$500.0 Million Fixed Rate Notes Due June 2028, Interest Equal To 3.75% [Member] [Domain]
Long-term debt		498.1	497.7
$750.0 million Fixed Rate Notes Due September 2043 Interest Equal To 5.3% [Member]
Long-term debt	[2]	744	743.7
$700.0 Million Fixed Rate Notes Due June 2048, Interest Equal To 4.15% [Member] [Domain] [Domain]
Long-term debt		691.3	690.9
$750.0 Million Fixed Rate Notes Due March 2032, Interest Equal To 2.65%
Long-term debt		742.9	$ 741.7
Fair Value, Inputs, level 2 [Member] | $750.0 Million Fixed Rate Notes Due March 2025, Interest Equal To 3.00% [Member]
Debt Instrument, Fair Value Disclosure		733.8
Fair Value, Inputs, level 2 [Member] | $500.0 Million Fixed Rate Notes Due June 2028, Interest Equal To 3.75% [Member] [Domain]
Debt Instrument, Fair Value Disclosure		489.3
Fair Value, Inputs, level 2 [Member] | $750.0 million Fixed Rate Notes Due September 2043 Interest Equal To 5.3% [Member]
Debt Instrument, Fair Value Disclosure		802.2
Fair Value, Inputs, level 2 [Member] | $700.0 Million Fixed Rate Notes Due June 2048, Interest Equal To 4.15% [Member] [Domain] [Domain]
Debt Instrument, Fair Value Disclosure		641
Fair Value, Inputs, level 2 [Member] | $750.0 Million Fixed Rate Notes Due March 2032, Interest Equal To 2.65%
Debt Instrument, Fair Value Disclosure		$ 669
[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 3.11%.

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unrealized Gain (Loss) on Investments	$ 1.4
Investments, Fair Value Disclosure	$ 8.6

Earnings Per Share (Basic and D

Earnings Per Share (Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net income attributable to CME Group	$ 3,226.2	$ 2,691	$ 2,636.4
Preferred Stock Dividends, Income Statement Impact	(44.2)	(38.9)	(19)
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	3.6	5.1	(0.3)
Net income	$ 3,226.2	$ 2,691	$ 2,636.9
Basic	359,023	358,713	358,340
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	477	468	589
Diluted	359,500	359,181	358,929
Earnings per common share, basic	$ 8.87	$ 7.41	$ 7.30
Earnings per common share, diluted	$ 8.86	$ 7.40	$ 7.29
Outstanding anti-dilutive options	455	158	86
Net Income Attributable to Common Shareholders of CME Group	$ 3,185.6	$ 2,657.2	$ 2,617.1
Restricted Stock [Member]
Outstanding anti-dilutive options	455	158	86
Retained Earnings [Member]
Net income attributable to CME Group	$ 3,226.2	$ 2,691	$ 2,636.4

Schedule II_Valuation and Qua_2

Schedule II—Valuation and Qualifying Accounts Schedule II—Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 8.1	$ 5.6	$ 5.4
Charged (credited) to costs and expenses	0.6	3.9	1.9
Other	(1.6)	(1.4)	(1.7)
Balance at end of year	7.1	8.1	5.6
Allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	0.4	0.6	11.3
Charged (credited) to costs and expenses	0	0	0
Other	0	0.2	10.7
Balance at end of year	$ 0.4	$ 0.4	$ 0.6