Debt Securities (Amortized Cost, Unrealized Gains And Losses, And Fair Value Of Investment Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	$ 11,262	$ 11,376
Available-for-sale securities, unrealized gains	63	116
Available-for-sale securities, unrealized losses	(410)	(380)
Available for sale, at fair value	10,915	11,112
Investment securities held to maturity	18	18
Held-to-maturity securities, unrealized gains	0	1
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	18	19
U.S. Treasury and agencies
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	1,227	1,332
Available-for-sale securities, unrealized gains	3	6
Available-for-sale securities, unrealized losses	(40)	(38)
Available for sale, at fair value	1,190	1,300
Obligations of states and political subdivisions
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	1,577	1,597
Available-for-sale securities, unrealized gains	26	47
Available-for-sale securities, unrealized losses	(20)	(15)
Available for sale, at fair value	1,583	1,629
Mortgage-backed securities and collateralized mortgage obligations
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	8,458	8,447
Available-for-sale securities, unrealized gains	34	63
Available-for-sale securities, unrealized losses	(350)	(327)
Available for sale, at fair value	8,142	8,183
Corporate and other securities
Debt and Equity Securities, FV-NI [Line Items]
Investment securities held to maturity	18	18
Held-to-maturity securities, unrealized gains	0	1
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	$ 18	$ 19

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) 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, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) 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, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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