Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Available-for-sale debt and other securities:
Realized gains	$ 29	$ 3
Realized losses	(29)	0
Net realized gains on available-for-sale debt and other securities	0	3
Trading debt securities:
Net realized losses	0	(1)
Net unrealized gains	0	11
Net trading debt securities gains	0	10
Equity securities:
Net realized gains	0	1
Net unrealized gains (losses)	4	(29)
Net equity securities gains (losses)	4	(28)
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	4	(15)
Commercial Banking Revenue and Wealth and Asset Management Revenue
Equity securities:
Securities gains (losses)	$ 1	$ (3)