Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 1,753	$ 1,739
Accumulated Amortization	(475)	(175)
Net Carrying Value	1,278	1,564
Rider and Merchant relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	1,054	1,007
Accumulated Amortization	(222)	(81)
Net Carrying Value	$ 832	$ 926
Weighted Average Remaining Useful Life - Years	7 years	8 years
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 495	$ 529
Accumulated Amortization	(206)	(69)
Net Carrying Value	$ 289	$ 460
Weighted Average Remaining Useful Life - Years	2 years	2 years
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 184	$ 183
Accumulated Amortization	(37)	(16)
Net Carrying Value	$ 147	$ 167
Weighted Average Remaining Useful Life - Years	7 years	7 years
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 15	$ 15
Accumulated Amortization	(7)	(6)
Net Carrying Value	$ 8	$ 9
Weighted Average Remaining Useful Life - Years	7 years	8 years
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 5	$ 5
Accumulated Amortization	(3)	(3)
Net Carrying Value	$ 2	$ 2
Weighted Average Remaining Useful Life - Years	0 years	0 years