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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 | Jun. 30, 2024 | Dec. 31, 2023
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Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | $ 31,612 | $ 30,864
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 27 | 62
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (3,102) | (2,822)
Available-for-sale debt securities, net carrying value | 28,537 | 28,104
Debt securities available for sale | 28,537 | 28,104
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 741 | 763
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (8) | (9)
Debt Securities held to maturity | 733 | 754
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (43) | (38)
Debt Securities held to maturity, estimated fair value | 690 | 716
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 1,486 | 1,322
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 1 | 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (97) | (99)
Available-for-sale debt securities, net carrying value | 1,390 | 1,223
Debt securities available for sale | 1,390 | 1,223
Federal agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 530 | 1,085
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 2 | 4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (20) | (46)
Available-for-sale debt securities, net carrying value | 512 | 1,043
Debt securities available for sale | 512 | 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 | 22,263 | 19,450
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 21 | 52
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (2,452) | (2,130)
Available-for-sale debt securities, net carrying value | 19,832 | 17,372
Debt securities available for sale | 19,832 | 17,372
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 228 | 247
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | (8) | (8)
Debt Securities held to maturity | 220 | 239
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (20) | (16)
Debt Securities held to maturity, estimated fair value | 200 | 223
Commercial agency |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 6,289 | 7,807
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 1 | 2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (490) | (502)
Available-for-sale debt securities, net carrying value | 5,800 | 7,307
Debt securities available for sale | 5,800 | 7,307
Schedule of Held-to-maturity Securities [Line Items] |  |
Debt Securities held to maturity, amortized cost | 513 | 516
Held To Maturity Debt Securities Gross Unrealized Gains | 0 | 0
Held To Maturity Debt Securities Gross Unrealized Losses | 0 | (1)
Debt Securities held to maturity | 513 | 515
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain | 0 | 0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss | (23) | (22)
Debt Securities held to maturity, estimated fair value | 490 | 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 | (11) | (10)
Available-for-sale debt securities, net carrying value | 81 | 83
Debt securities available for sale | 81 | 83
Corporate and other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Amortized Cost | 950 | 1,105
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 2 | 4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | (32) | (35)
Available-for-sale debt securities, net carrying value | 920 | 1,074
Debt securities available for sale | $ 920 | $ 1,074

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