Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Available-for-sale debt and other securities:
Realized gains	$ 0	$ 1	$ 4	$ 34
Realized losses	0	0	0	(30)
Impairment losses	(11)	(1)	(21)	(5)
Net losses on available-for-sale debt and other securities	(11)	0	(17)	(1)
Trading debt securities:
Net realized gains	1	0	0	0
Net unrealized gains	0	0	0	2
Net trading debt securities gains	1	0	0	2
Equity securities:
Net realized gains	4	2	15	3
Net unrealized gains (losses)	16	(9)	25	(1)
Net equity securities gains (losses)	20	(7)	40	2
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	10	(7)	23	3
Commercial Banking Revenue and Wealth and Asset Management Revenue
Equity securities:
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	$ 7	$ 2	$ 9	$ 3