Investment Securities - Gains and Losses Recognized in Income from Securities (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Available-for-sale debt and other securities:
Realized gains	$ 3	$ 0	$ 9	$ 4
Realized losses	(3)	0	(9)	0
Impairment losses	0	(11)	0	(21)
Net losses on available-for-sale debt and other securities	0	(11)	0	(17)
Net realized gains	0	1	0	0
Net unrealized gains	0	0	0	0
Net trading debt securities gains	0	1	0	0
Equity securities:
Net realized (losses) gains	3	4	(2)	15
Net unrealized gains	7	16	19	25
Net equity securities gains	10	20	17	40
Total (losses) gains recognized in income from available-for-sale debt and other securities, trading debt securities and equity securities	10	10	17	23
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	$ 5	$ 7	$ 11	$ 9

Impairment Loss, Debt Securities, Portion Recognized in Earnings

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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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