Segments (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment									1
Number of reportable segments | segment									1
Segment Reporting Information [Line Items]
Total net revenues	$ 2,613	$ 2,501	$ 2,668	$ 2,638	$ 2,478	$ 2,258	$ 2,337	$ 1,821	$ 10,420	$ 8,894	$ 7,429
Total long-lived tangible assets	1,525				1,722				1,525	1,722
U.S.
Segment Reporting Information [Line Items]
Total net revenues									5,048	4,151	3,303
Total long-lived tangible assets	1,400				1,575				1,400	1,575
United Kingdom
Segment Reporting Information [Line Items]
Total net revenues									1,913	1,678	1,323
Germany
Segment Reporting Information [Line Items]
Total net revenues									1,249	1,106	1,034
Rest of world
Segment Reporting Information [Line Items]
Total net revenues									2,210	1,959	1,769
International
Segment Reporting Information [Line Items]
Total long-lived tangible assets	$ 125				$ 147				125	147
Net transaction revenues
Segment Reporting Information [Line Items]
Total net revenues									9,772	8,243	6,581
Marketing services and other revenues
Segment Reporting Information [Line Items]
Total net revenues									$ 648	$ 651	$ 848