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Investment Securities - Schedule of Amortized Cost and Fair Value of Investment Securities (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Investment securities available for sale |  |
Amortized Cost | $ 20,688 | $ 9,967
Gross Unrealized Gains | 115 | 1
Gross Unrealized Losses | (867) | (973)
Investment securities available for sale | 19,936 | 8,995
Investment in marketable equity securities |  |
Amortized Cost | 75 | 75
Gross Unrealized Gains | 17 | 21
Gross Unrealized Losses | (8) | (1)
Fair Value | 84 | 95
Investment securities held to maturity |  |
Amortized Cost | 9,979 | 10,279
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (1,476) | (1,484)
Fair Value | 8,503 | 8,795
Total investment securities |  |
Amortized Cost | 30,742 | 20,321
Gross Unrealized Gains | 132 | 22
Gross Unrealized Losses | (2,351) | (2,458)
Fair Value | 28,523 | 17,885
U.S. Treasury |  |
Investment securities available for sale |  |
Amortized Cost | 10,554 | 2,035
Gross Unrealized Gains | 34 | 0
Gross Unrealized Losses | (80) | (137)
Investment securities available for sale | 10,508 | 1,898
Investment securities held to maturity |  |
Amortized Cost | 479 | 474
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (40) | (50)
Fair Value | 439 | 424
Government agency |  |
Investment securities available for sale |  |
Amortized Cost | 120 | 164
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (3) | (2)
Investment securities available for sale | 117 | 162
Investment securities held to maturity |  |
Amortized Cost | 1,506 | 1,548
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (143) | (186)
Fair Value | 1,363 | 1,362
Residential mortgage-backed securities |  |
Investment securities available for sale |  |
Amortized Cost | 7,154 | 5,424
Gross Unrealized Gains | 72 | 1
Gross Unrealized Losses | (540) | (630)
Investment securities available for sale | 6,686 | 4,795
Investment securities held to maturity |  |
Amortized Cost | 4,205 | 4,605
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (644) | (723)
Fair Value | 3,561 | 3,882
Commercial mortgage-backed securities |  |
Investment securities available for sale |  |
Amortized Cost | 2,319 | 1,774
Gross Unrealized Gains | 9 | 0
Gross Unrealized Losses | (197) | (170)
Investment securities available for sale | 2,131 | 1,604
Investment securities held to maturity |  |
Amortized Cost | 3,489 | 3,355
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (614) | (484)
Fair Value | 2,875 | 2,871
Corporate bonds |  |
Investment securities available for sale |  |
Amortized Cost | 529 | 570
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (47) | (34)
Investment securities available for sale | 482 | 536
Municipal bonds |  |
Investment securities available for sale |  |
Amortized Cost | 12 |
Gross Unrealized Gains | 0 |
Gross Unrealized Losses | 0 |
Investment securities available for sale | 12 |
Supranational securities |  |
Investment securities held to maturity |  |
Amortized Cost | 298 | 295
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (35) | (41)
Fair Value | 263 | 254
Other |  |
Investment securities held to maturity |  |
Amortized Cost | 2 | 2
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | $ 2 | $ 2

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