Revenue Recognition - Schedule of Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenues									$ 6,547	$ 6,276	$ 5,843
Transaction-based expenses									1,345	1,297	1,205
Total revenues, less transaction-based expenses	$ 1,298	$ 1,336	$ 1,298	$ 1,270	$ 1,308	$ 1,200	$ 1,246	$ 1,225	5,202	4,979	4,638
Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues									3,887	3,717	3,333
Transaction-based expenses									1,345	1,297	1,205
Total revenues, less transaction-based expenses									2,542	2,420	2,128
Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues									2,660	2,559	2,510
Transaction-based expenses									0	0	0
Total revenues, less transaction-based expenses									2,660	2,559	2,510
Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenues, less transaction-based expenses									2,194	2,074	1,813
Services transferred at a point in time | Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues, less transaction-based expenses									2,194	2,074	1,813
Services transferred at a point in time | Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues, less transaction-based expenses									0	0	0
Services transferred over time
Disaggregation of Revenue [Line Items]
Total revenues, less transaction-based expenses									3,008	2,905	2,825
Services transferred over time | Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues, less transaction-based expenses									348	346	315
Services transferred over time | Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues, less transaction-based expenses									2,660	2,559	2,510
Transaction and clearing, net
Disaggregation of Revenue [Line Items]
Total revenues									3,627	3,483	3,131
Transaction and clearing, net | Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues									3,627	3,483	3,131
Transaction and clearing, net | Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Data services
Disaggregation of Revenue [Line Items]
Total revenues									2,211	2,115	2,084
Data services | Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Data services | Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues									2,211	2,115	2,084
Listings
Disaggregation of Revenue [Line Items]
Total revenues									449	444	426
Listings | Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues									0	0	0
Listings | Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues									449	444	426
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues									260	234	202
Other revenues | Trading & Clearing Segment
Disaggregation of Revenue [Line Items]
Total revenues									260	234	202
Other revenues | Data & Listings Segment
Disaggregation of Revenue [Line Items]
Total revenues									$ 0	$ 0	$ 0