Derivative Instruments and Hedging Activities (Statement of Gains and Losses on Derivative Instruments Reported in Statement of Comprehensive Income) (Details) - Not designated as hedging instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	$ (29)	$ (41)	$ (14)
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(4)	(29)	(10)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(1)	(7)	(4)
Other credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(24)	(5)	0
(Loss) gain on mortgage and automotive loans, net | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(12)	(10)	1
Other income, net of losses | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	8	(19)	(11)
Other income, net of losses | Other credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(24)	(1)	0
Other operating expenses | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(1)	(7)	(4)
Interest and fees on finance receivables and loans | Other credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	$ 0	$ (4)	$ 0