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	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	$ (3)	$ (17)
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	1	(7)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(3)	(2)
Other credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(1)	(8)
Loss on mortgage and automotive loans, net | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(2)	(7)
Other income, net of losses | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	3	0
Other income, net of losses | Other credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	(1)	(8)
Other operating expenses | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments recognized in earnings	$ (3)	$ (2)