Goodwill and Intangible Assets - Schedule of Components of Identifiable Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,289	$ 2,133
Accumulated Amortization	(1,511)	(1,308)
Net Carrying Amount	778	825
Customer lists and user base
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,114	1,134
Accumulated Amortization	(700)	(623)
Net Carrying Amount	$ 414	$ 511
Weighted Average Useful Life (Years)	7 years	7 years
Marketing related
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 294	$ 301
Accumulated Amortization	(239)	(207)
Net Carrying Amount	$ 55	$ 94
Weighted Average Useful Life (Years)	3 years	3 years
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 445	$ 453
Accumulated Amortization	(343)	(269)
Net Carrying Amount	$ 102	$ 184
Weighted Average Useful Life (Years)	3 years	3 years
All other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 436	$ 245
Accumulated Amortization	(229)	(209)
Net Carrying Amount	$ 207	$ 36
Weighted Average Useful Life (Years)	7 years	5 years