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Securities - Schedule of Available-for-sale and Held-to-maturity Securities (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
AFS debt securities: |  |
Amortized Cost | $ 6,916,491 | $ 6,879,225
Gross Unrealized Gains | 783 | 498
Gross Unrealized Losses | (728,937) | (844,730)
Fair Value | 6,188,337 | 6,034,993
HTM debt securities |  |
Amortized Cost | 2,956,040 | 3,001,868
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (502,069) | (546,697)
Fair Value | 2,453,971 | 2,455,171
Total debt securities |  |
Amortized Cost | 9,872,531 | 9,881,093
Gross Unrealized Gains | 783 | 498
Gross Unrealized Losses | (1,231,006) | (1,391,427)
Fair Value | 8,642,308 | 8,490,164
U.S. Treasury securities |  |
AFS debt securities: |  |
Amortized Cost | 1,112,587 | 676,306
Gross Unrealized Gains | 101 | 0
Gross Unrealized Losses | (52,313) | (70,103)
Fair Value | 1,060,375 | 606,203
HTM debt securities |  |
Amortized Cost | 529,548 | 524,081
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (40,997) | (52,612)
Fair Value | 488,551 | 471,469
U.S. government agency and U.S. government-sponsored enterprise debt securities |  |
AFS debt securities: |  |
Amortized Cost | 412,086 | 517,806
Gross Unrealized Gains | 0 | 67
Gross Unrealized Losses | (47,640) | (56,266)
Fair Value | 364,446 | 461,607
HTM debt securities |  |
Amortized Cost | 1,001,836 | 998,972
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (186,904) | (209,560)
Fair Value | 814,932 | 789,412
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 531,377 | 577,392
Gross Unrealized Gains | 158 | 0
Gross Unrealized Losses | (63,276) | (77,123)
Fair Value | 468,259 | 500,269
HTM debt securities |  |
Amortized Cost | 493,348 | 506,965
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (88,968) | (98,566)
Fair Value | 404,380 | 408,399
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 1,956,927 | 2,011,054
Gross Unrealized Gains | 380 | 41
Gross Unrealized Losses | (229,713) | (248,900)
Fair Value | 1,727,594 | 1,762,195
HTM debt securities |  |
Amortized Cost | 742,436 | 782,141
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (142,119) | (148,230)
Fair Value | 600,317 | 633,911
Municipal securities: |  |
AFS debt securities: |  |
Amortized Cost | 297,283 | 303,884
Gross Unrealized Gains | 75 | 3
Gross Unrealized Losses | (36,342) | (46,788)
Fair Value | 261,016 | 257,099
HTM debt securities |  |
Amortized Cost | 188,872 | 189,709
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (43,081) | (37,729)
Fair Value | 145,791 | 151,980
Non-agency commercial mortgage-backed Securities |  |
AFS debt securities: |  |
Amortized Cost | 409,578 | 447,512
Gross Unrealized Gains | 0 | 213
Gross Unrealized Losses | (42,062) | (49,396)
Fair Value | 367,516 | 398,329
Non-agency residential mortgage-backed Securities |  |
AFS debt securities: |  |
Amortized Cost | 643,335 | 762,202
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (89,664) | (112,978)
Fair Value | 553,671 | 649,224
Corporate debt securities |  |
AFS debt securities: |  |
Amortized Cost | 653,501 | 673,502
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (151,076) | (147,228)
Fair Value | 502,425 | 526,274
Foreign government bonds |  |
AFS debt securities: |  |
Amortized Cost | 239,333 | 241,165
Gross Unrealized Gains | 69 | 174
Gross Unrealized Losses | (11,528) | (14,286)
Fair Value | 227,874 | 227,053
Asset-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 43,234 | 51,152
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (934) | (2,076)
Fair Value | 42,300 | 49,076
CLOs |  |
AFS debt securities: |  |
Amortized Cost | 617,250 | 617,250
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (4,389) | (19,586)
Fair Value | $ 612,861 | $ 597,664

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