Segments (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 [Abstract]
Number of reportable segments | segment			1
Net Revenues by Type
Total consolidated net revenue	$ 2,606	$ 2,083	$ 7,403	$ 6,400
U.S.
Net Revenues by Type
Total consolidated net revenue	1,078	804	2,986	2,466
United Kingdom
Net Revenues by Type
Total consolidated net revenue	425	313	1,196	981
South Korea
Net Revenues by Type
Total consolidated net revenue	350	288	996	885
Germany
Net Revenues by Type
Total consolidated net revenue	265	248	795	796
Rest of world
Net Revenues by Type
Total consolidated net revenue	488	430	1,430	1,272
Operating Segments
Net Revenues by Type
Total consolidated net revenue	2,606	2,083	7,403	6,400
Net transaction revenues | Operating Segments
Net Revenues by Type
Total consolidated net revenue	2,355	1,829	6,702	5,601
Marketing services and other revenues | Operating Segments
Net Revenues by Type
Total consolidated net revenue	$ 251	$ 254	$ 701	$ 799