Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Available-for-sale debt and other securities:
Realized gains	$ 9	$ 7		$ 12	$ 8
Realized losses	(9)	0		(9)	(10)
Impairment losses	0	0	$ (7)	0	(7)
Net realized gains (losses) on available-for-sale debt and other securities	0	7		3	(9)
Trading debt securities:
Net realized (losses) gains	0	1		(1)	(1)
Net unrealized gains (losses)	0	(8)		11	1
Net trading debt securities gains (losses)	0	(7)		10	0
Equity securities:
Net realized gains	0	1		1	4
Net unrealized (losses) gains	(32)	10		(62)	17
Net equity securities (losses) gains	(32)	11		(61)	21
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	(32)	11		(48)	12
Commercial Banking Revenue and Wealth and Asset Management Revenue
Investment Holdings [Line Items]
Securities gains (losses)	$ (1)	$ (1)		$ (4)	$ (3)

Total available for sale and trading securities gains losses.

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Amount of unrealized and realized gain (loss) 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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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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Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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