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Debt Securities (Schedule Of Amortized Cost, Gross Unrealized Gains And Losses, And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity) (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
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Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | $ 30,864 | $ 31,367
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 62 | 1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (2,822) | (3,435)
Available-for-sale debt securities, net carrying value | 28,104 | 27,933
Debt securities available for sale | 28,104 | 27,933
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 763 | 812
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (9) | (11)
Debt Securities held to maturity | 754 | 801
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (38) | (50)
Debt Securities held to maturity, estimated fair value | 716 | 751
US Treasury Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 1,322 | 1,310
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (99) | (123)
Available-for-sale debt securities, net carrying value | 1,223 | 1,187
Debt securities available for sale | 1,223 | 1,187
Federal agency securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 1,085 | 898
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 4 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (46) | (62)
Available-for-sale debt securities, net carrying value | 1,043 | 836
Debt securities available for sale | 1,043 | 836
US States and Political Subdivisions Debt Securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 2 | 2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | 0 | 0
Available-for-sale debt securities, net carrying value | 2 | 2
Debt securities available for sale | 2 | 2
Residential Agency [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 19,450 | 19,477
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 52 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (2,130) | (2,523)
Available-for-sale debt securities, net carrying value | 17,372 | 16,954
Debt securities available for sale | 17,372 | 16,954
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 247 | 289
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (8) | (10)
Debt Securities held to maturity | 239 | 279
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (16) | (21)
Debt Securities held to maturity, estimated fair value | 223 | 258
Residential Non-Agency [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost |  | 1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax |  | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax |  | 0
Available-for-sale debt securities, net carrying value |  | 1
Debt securities available for sale |  | 1
Commercial Agency [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 7,807 | 8,262
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 2 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (502) | (649)
Available-for-sale debt securities, net carrying value | 7,307 | 7,613
Debt securities available for sale | 7,307 | 7,613
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 516 | 523
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (1) | (1)
Debt Securities held to maturity | 515 | 522
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (22) | (29)
Debt Securities held to maturity, estimated fair value | 493 | 493
Commercial Non Agency [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 93 | 198
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (10) | (12)
Available-for-sale debt securities, net carrying value | 83 | 186
Debt securities available for sale | 83 | 186
Corporate and other debt securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 1,105 | 1,219
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 4 | 1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (35) | (66)
Available-for-sale debt securities, net carrying value | 1,074 | 1,154
Debt securities available for sale | $ 1,074 | $ 1,154

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