Segment Reporting (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) segment	Sep. 30, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2
Number of operating segments | segment			2
Revenues:
Total revenues	$ 1,930	$ 1,663	$ 6,011	$ 4,880
Transaction-based expenses	519	327	1,646	976
Total revenues, less transaction-based expenses	1,411	1,336	4,365	3,904
Operating expenses	784	630	2,112	1,853
Operating Income (Loss)	627	706	2,253	2,051
Trading and Clearing Segment
Revenues:
Total revenues	1,230	996	3,950	2,892
Total revenues, less transaction-based expenses	711	669	2,304	1,916
Operating expenses	406	255	998	732
Operating Income (Loss)	305	414	1,306	1,184
Data and Listings Segment
Revenues:
Total revenues	700	667	2,061	1,988
Transaction-based expenses	0	0	0	0
Total revenues, less transaction-based expenses	700	667	2,061	1,988
Operating expenses	378	375	1,114	1,121
Operating Income (Loss)	322	292	947	867
Sales Revenue, Net | Trading and Clearing Segment | Two clearing members
Revenues:
Total revenues	$ 76		$ 276
Concentration risk, percentage	11.00%		12.00%
Sales Revenue, Net | Trading and Clearing Segment | One clearing member
Revenues:
Total revenues		$ 92		$ 286
Concentration risk, percentage		14.00%		15.00%
Energy futures and options contracts
Revenues:
Total revenues	$ 229	$ 265	$ 858	$ 749
Energy futures and options contracts | Trading and Clearing Segment
Revenues:
Total revenues	229	265	858	749
Energy futures and options contracts | Data and Listings Segment
Revenues:
Total revenues	0	0	0	0
Agricultural and metals futures and options contracts
Revenues:
Total revenues	54	60	197	194
Agricultural and metals futures and options contracts | Trading and Clearing Segment
Revenues:
Total revenues	54	60	197	194
Agricultural and metals futures and options contracts | Data and Listings Segment
Revenues:
Total revenues	0	0	0	0
Financial futures and options contracts
Revenues:
Total revenues	76	91	275	252
Financial futures and options contracts | Trading and Clearing Segment
Revenues:
Total revenues	76	91	275	252
Financial futures and options contracts | Data and Listings Segment
Revenues:
Total revenues	0	0	0	0
Cash equities and equity options
Revenues:
Total revenues	593	401	1,934	1,201
Cash equities and equity options | Trading and Clearing Segment
Revenues:
Total revenues	593	401	1,934	1,201
Cash equities and equity options | Data and Listings Segment
Revenues:
Total revenues	0	0	0	0
Fixed income and credit
Revenues:
Total revenues	191	101	424	268
Fixed income and credit | Trading and Clearing Segment
Revenues:
Total revenues	191	101	424	268
Fixed income and credit | Data and Listings Segment
Revenues:
Total revenues	0	0	0	0
OTC and other transactions
Revenues:
Total revenues	12	11	38	34
OTC and other transactions | Trading and Clearing Segment
Revenues:
Total revenues	12	11	38	34
OTC and other transactions | Data and Listings Segment
Revenues:
Total revenues	0	0	0	0
Pricing and analytics
Revenues:
Total revenues	287	273	845	809
Pricing and analytics | Trading and Clearing Segment
Revenues:
Total revenues	0	0	0	0
Pricing and analytics | Data and Listings Segment
Revenues:
Total revenues	287	273	845	809
Exchange data and feeds
Revenues:
Total revenues	189	172	552	528
Exchange data and feeds | Trading and Clearing Segment
Revenues:
Total revenues	0	0	0	0
Exchange data and feeds | Data and Listings Segment
Revenues:
Total revenues	189	172	552	528
Desktops and connectivity
Revenues:
Total revenues	113	108	330	315
Desktops and connectivity | Trading and Clearing Segment
Revenues:
Total revenues	0	0	0	0
Desktops and connectivity | Data and Listings Segment
Revenues:
Total revenues	113	108	330	315
Listings
Revenues:
Total revenues	111	114	334	336
Listings | Trading and Clearing Segment
Revenues:
Total revenues	0	0	0	0
Listings | Data and Listings Segment
Revenues:
Total revenues	111	114	334	336
Other revenues
Revenues:
Total revenues	75	67	224	194
Other revenues | Trading and Clearing Segment
Revenues:
Total revenues	75	67	224	194
Other revenues | Data and Listings Segment
Revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0