Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 9,881	$ 1,119
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(256)	(15)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	14,303	24,555
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,729)	(2,807)
Debt Securities, Available-for-sale, Unrealized Loss Position	24,184	25,674
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,985)	(2,822)
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	4,226	716
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(944)	(46)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	4,226	716
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(944)	(46)
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	612	6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(14)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,033	1,201
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(73)	(99)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,645	1,207
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(87)	(99)
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	155	237
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3)	(5)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	195	666
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(14)	(41)
Debt Securities, Available-for-sale, Unrealized Loss Position	350	903
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(17)	(46)
Residential agency
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	8,012	241
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(203)	(3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	9,605	15,144
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,354)	(2,127)
Debt Securities, Available-for-sale, Unrealized Loss Position	17,617	15,385
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(1,557)	(2,130)
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	3,734	223
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(929)	(23)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	3,734	223
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(929)	(23)
Commercial agency
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,043	612
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(35)	(7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,991	6,583
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(265)	(495)
Debt Securities, Available-for-sale, Unrealized Loss Position	4,034	7,195
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(300)	(502)
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	493
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(15)	(23)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	492	493
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(15)	(23)
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	82	82
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(10)	(10)
Debt Securities, Available-for-sale, Unrealized Loss Position	82	82
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(10)	(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	59	23
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	397	879
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(13)	(35)
Debt Securities, Available-for-sale, Unrealized Loss Position	456	902
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (14)	$ (35)

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