Debt Securities (Schedule Of Gross Unrealized Losses And Estimated Fair Value Of Securities Available For Sale) (Details) - USD ($) $ in Millions	Jun. 30, 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	$ 4,201	$ 1,119
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(50)	(15)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	21,926	24,555
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(3,052)	(2,807)
Debt Securities, Available-for-sale, Unrealized Loss Position	26,127	25,674
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(3,102)	(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	690	716
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(51)	(46)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	690	716
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(51)	(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	137	6
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	1,095	1,201
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(97)	(99)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,232	1,207
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(97)	(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	117	237
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	(5)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	296	666
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(19)	(41)
Debt Securities, Available-for-sale, Unrealized Loss Position	413	903
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(20)	(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	3,703	241
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(46)	(3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	14,133	15,144
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2,406)	(2,127)
Debt Securities, Available-for-sale, Unrealized Loss Position	17,836	15,385
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(2,452)	(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	200	223
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(27)	(23)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	200	223
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(27)	(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	139	612
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2)	(7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,632	6,583
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(488)	(495)
Debt Securities, Available-for-sale, Unrealized Loss Position	5,771	7,195
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(490)	(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	490	493
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(24)	(23)
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value	490	493
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss	(24)	(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	81	82
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(11)	(10)
Debt Securities, Available-for-sale, Unrealized Loss Position	81	82
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(11)	(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	105	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	689	879
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(31)	(35)
Debt Securities, Available-for-sale, Unrealized Loss Position	794	902
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (32)	$ (35)

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

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