Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Available-for-sale debt and other securities:
Realized gains	$ 3	$ 2
Realized losses	0	(10)
Impairment losses	0	(7)
Net realized gains (losses) on available-for-sale debt and other securities	3	(15)
Trading debt securities:
Net realized losses	(1)	(2)
Net unrealized gains	11	9
Net trading debt securities gains	10	7
Equity securities:
Net realized gains	1	2
Net unrealized (losses) gains	(29)	7
Net equity securities (losses) gains	(28)	9
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	(15)	1
Commercial Banking Revenue and Wealth and Asset Management Revenue
Investment Holdings [Line Items]
Securities gains (losses)	$ (3)	$ (2)

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 realized 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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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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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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