Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 17,379	$ 12,378
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,507)	(216)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	10,436	1,446
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,928)	(59)
Debt Securities, Available-for-sale, Unrealized Loss Position	27,815	13,824
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(3,435)	(275)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	720
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(55)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	31
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(5)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	751
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(60)
Residential Agency [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	9,350	9,528
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,005)	(171)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7,578	686
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,518)	(27)
Debt Securities, Available-for-sale, Unrealized Loss Position	16,928	10,214
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(2,523)	(198)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	251
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(29)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	7
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	258
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(30)
Commercial Agency [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	6,110	1,333
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(400)	(29)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,503	760
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(249)	(32)
Debt Securities, Available-for-sale, Unrealized Loss Position	7,613	2,093
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(649)	(61)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Estimated Fair Value	469
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(26)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Estimated Fair Value	24
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	493
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(30)
Corporate and other debt securities [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		444
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Debt Securities, Available-for-sale, Unrealized Loss Position		444
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		(6)
US Treasury Securities [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	276	1,010
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8)	(7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	903	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(115)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	1,179	1,010
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(123)	(7)
Federal agency securities [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	766	63
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(50)	(3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	53	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(12)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	819	63
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(62)	$ (3)
Corporate and other debt securities [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	736
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(36)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	354
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(30)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,090
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(66)
Commercial Non Agency [Member]
Unrealized Loss And Fair Value On Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	141
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	45
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4)
Debt Securities, Available-for-sale, Unrealized Loss Position	186
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (12)

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

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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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