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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 | Sep. 30, 2024 | Dec. 31, 2023
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Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | $ 30,090 | $ 30,864
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 234 | 62
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (1,626) | (2,822)
Available-for-sale debt securities, net carrying value | 28,698 | 28,104
Debt securities available for sale | 28,698 | 28,104
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 3,230 | 763
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (443) | (9)
Debt Securities held to maturity | 2,787 | 754
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (28) | (38)
Debt Securities held to maturity, estimated fair value | 2,759 | 716
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 2,102 | 1,322
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 13 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (69) | (99)
Available-for-sale debt securities, net carrying value | 2,046 | 1,223
Debt securities available for sale | 2,046 | 1,223
Federal agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 461 | 1,085
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 6 | 4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (10) | (46)
Available-for-sale debt securities, net carrying value | 457 | 1,043
Debt securities available for sale | 457 | 1,043
Obligations of states and political subdivisions |  |
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 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 21,564 | 19,450
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 199 | 52
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (1,304) | (2,130)
Available-for-sale debt securities, net carrying value | 20,459 | 17,372
Debt securities available for sale | 20,459 | 17,372
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 2,718 | 247
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (442) | (8)
Debt Securities held to maturity | 2,276 | 239
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (16) | (16)
Debt Securities held to maturity, estimated fair value | 2,260 | 223
Commercial agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 5,135 | 7,807
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 10 | 2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (223) | (502)
Available-for-sale debt securities, net carrying value | 4,922 | 7,307
Debt securities available for sale | 4,922 | 7,307
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 512 | 516
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 | 511 | 515
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (12) | (22)
Debt Securities held to maturity, estimated fair value | 499 | 493
Commercial non-agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 92 | 93
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 0 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (7) | (10)
Available-for-sale debt securities, net carrying value | 85 | 83
Debt securities available for sale | 85 | 83
Corporate and other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 734 | 1,105
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 6 | 4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (13) | (35)
Available-for-sale debt securities, net carrying value | 727 | 1,074
Debt securities available for sale | $ 727 | $ 1,074

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