Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 7,315	$ 9,881
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(136)	(256)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12,730	14,303
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,266)	(1,729)
Debt Securities, Available-for-sale, Unrealized Loss Position	20,045	24,184
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,402)	(1,985)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	0	0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	5,063	4,226
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,007)	(944)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	5,063	4,226
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(1,007)	(944)
U.S. Treasury securities
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	539	612
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(12)	(14)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,020	1,033
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(62)	(73)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,559	1,645
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(74)	(87)
Federal agency securities
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	76	155
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	(3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	183	195
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(11)	(14)
Debt Securities, Available-for-sale, Unrealized Loss Position	259	350
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(12)	(17)
Residential agency
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	5,798	8,012
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(102)	(203)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	8,421	9,605
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(974)	(1,354)
Debt Securities, Available-for-sale, Unrealized Loss Position	14,219	17,617
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,076)	(1,557)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	0	0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	4,571	3,734
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(994)	(929)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	4,571	3,734
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(994)	(929)
Commercial agency
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	902	1,043
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(21)	(35)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,718	2,991
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(200)	(265)
Debt Securities, Available-for-sale, Unrealized Loss Position	3,620	4,034
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(221)	(300)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	0	0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	492	492
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(13)	(15)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	492	492
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(13)	(15)
Commercial non-agency
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	83	82
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(9)	(10)
Debt Securities, Available-for-sale, Unrealized Loss Position	83	82
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(9)	(10)
Corporate and other debt securities
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	59
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	305	397
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(10)	(13)
Debt Securities, Available-for-sale, Unrealized Loss Position	305	456
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (10)	$ (14)

Unrealized Loss And Fair Value Available For Sale Securities [Line Items]

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