Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Available-for-sale debt and other securities:
Realized gains	$ 4	$ 9	$ 34	$ 12
Realized losses	0	(9)	(30)	(9)
Impairment losses	(4)	0	(4)	0
Net realized gains on available-for-sale debt and other securities	0	0	0	3
Trading debt securities:
Net realized losses	0	0	0	(1)
Net unrealized gains	2	0	2	11
Net trading debt securities gains	2	0	2	10
Equity securities:
Net realized gains	1	0	2	1
Net unrealized gains (losses)	4	(32)	7	(62)
Net equity securities gains (losses)	5	(32)	9	(61)
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	7	(32)	11	(48)
Commercial Banking Revenue and Wealth and Asset Management Revenue
Equity securities:
Securities gains (losses)	$ (1)	$ (1)	$ 0	$ (4)