Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($) $ in Millions	Sep. 30, 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	$ 1,978	$ 9,881
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(21)	(256)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12,009	14,303
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(977)	(1,729)
Debt Securities, Available-for-sale, Unrealized Loss Position	13,987	24,184
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(998)	(1,985)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	197	0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	5,519	4,226
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(945)	(944)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	5,716	4,226
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(946)	(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	551	612
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(7)	(14)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,031	1,033
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(52)	(73)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,582	1,645
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(59)	(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	234	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	138	195
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(8)	(14)
Debt Securities, Available-for-sale, Unrealized Loss Position	372	350
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(9)	(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	1,193	8,012
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	(203)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	8,144	9,605
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(752)	(1,354)
Debt Securities, Available-for-sale, Unrealized Loss Position	9,337	17,617
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(765)	(1,557)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	197	0
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	5,118	3,734
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(937)	(929)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	5,315	3,734
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(938)	(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	0	1,043
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(35)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,430	2,991
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(152)	(265)
Debt Securities, Available-for-sale, Unrealized Loss Position	2,430	4,034
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(152)	(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	401	492
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(8)	(15)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	401	492
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(8)	(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	84	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	84	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	182	397
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4)	(13)
Debt Securities, Available-for-sale, Unrealized Loss Position	182	456
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (4)	$ (14)

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

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