Other Assets (Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (78)	$ (59)
Total intangible assets, gross	207	109
Net intangible assets	129	50
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2022	31
2023	25
2024	18
2025	14
2026	14
Technology
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	83	12
Accumulated amortization	(9)	(6)
Net carrying value	74	6
Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	58	58
Accumulated amortization	(42)	(31)
Net carrying value	16	27
Purchased credit card relationships
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	25	0
Accumulated amortization	0	0
Net carrying value	25	0
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	2	0
Accumulated amortization	0	0
Net carrying value	2	0
Other
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	39	39
Accumulated amortization	(27)	(22)
Net carrying value	$ 12	$ 17