Debt Securities (Schedule Of Fair Value And Unrealized Losses Of Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 2,732	$ 4,123
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(29)	(90)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,780	2,850
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(381)	(501)
Debt Securities, Available-for-sale, Unrealized Loss Position	5,512	6,973
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(410)	(591)
U.S. Treasury and agencies
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	50	185
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	774	795
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(43)	(71)
Debt Securities, Available-for-sale, Unrealized Loss Position	824	980
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(43)	(74)
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	110	539
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	(8)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	222	225
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(17)	(24)
Debt Securities, Available-for-sale, Unrealized Loss Position	332	764
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(18)	(32)
Mortgage-backed securities and collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,572	3,399
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(28)	(79)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,784	1,830
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(321)	(406)
Debt Securities, Available-for-sale, Unrealized Loss Position	4,356	5,229
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (349)	$ (485)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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