Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale debt and other securities:
Realized gains	$ 34	$ 47	$ 60
Realized losses	(19)	(2)	(50)
Impairment losses(a)	(19)	0	(1)
Net realized (losses) gains on available-for-sale debt and other securities	(4)	45	9
Trading debt securities:
Net realized (losses) gains	(2)	2	3
Net unrealized losses	(3)	0	0
Net trading debt securities (losses) gains	(5)	2	3
Equity securities:
Net realized gains	7	10	5
Net unrealized (losses) gains	(7)	7	26
Net equity securities gains	0	17	31
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	(9)	64	43
Commercial Banking Revenue and Wealth and Asset Management Revenue
Investment Holdings [Line Items]
Securities gains (losses)	$ (7)	$ 5	$ 7

Total available for sale and trading securities gains losses.

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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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