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Securities - Schedule of Debt Securities (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
AFS debt securities: |  |
Amortized Cost | $ 10,667,293 | $ 6,916,491
Gross Unrealized Gains | 37,644 | 783
Gross Unrealized Losses | (571,060) | (728,937)
Fair Value | 10,133,877 | 6,188,337
HTM debt securities: |  |
Amortized Cost | 2,928,399 | 2,956,040
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (418,047) | (502,069)
Fair Value | 2,510,352 | 2,453,971
Total debt securities |  |
Amortized Cost | 13,595,692 | 9,872,531
Gross Unrealized Gains | 37,644 | 783
Gross Unrealized Losses | (989,107) | (1,231,006)
Fair Value | 12,644,229 | 8,642,308
AFS and HTM, accrued interest | 40,000 | 44,000
Government National Mortgage Association (GNMA) |  |
AFS debt securities: |  |
Amortized Cost | 6,400,000 | 1,300,000
Fair Value | 6,300,000 | 1,200,000
HTM debt securities: |  |
Amortized Cost | 88,000 | 92,000
Fair Value | 72,000 | 75,000
U.S. Treasury securities |  |
AFS debt securities: |  |
Amortized Cost | 676,294 | 1,112,587
Gross Unrealized Gains | 0 | 101
Gross Unrealized Losses | (34,721) | (52,313)
Fair Value | 641,573 | 1,060,375
HTM debt securities: |  |
Amortized Cost | 533,683 | 529,548
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (28,539) | (40,997)
Fair Value | 505,144 | 488,551
U.S. government agency and U.S. government-sponsored enterprise debt securities |  |
AFS debt securities: |  |
Amortized Cost | 309,277 | 412,086
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (36,829) | (47,640)
Fair Value | 272,448 | 364,446
HTM debt securities: |  |
Amortized Cost | 1,003,947 | 1,001,836
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (155,147) | (186,904)
Fair Value | 848,800 | 814,932
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 482,291 | 531,377
Gross Unrealized Gains | 770 | 158
Gross Unrealized Losses | (38,184) | (63,276)
Fair Value | 444,877 | 468,259
HTM debt securities: |  |
Amortized Cost | 489,133 | 493,348
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (69,765) | (88,968)
Fair Value | 419,368 | 404,380
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 7,028,428 | 1,956,927
Gross Unrealized Gains | 35,106 | 380
Gross Unrealized Losses | (195,610) | (229,713)
Fair Value | 6,867,924 | 1,727,594
HTM debt securities: |  |
Amortized Cost | 713,634 | 742,436
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (124,829) | (142,119)
Fair Value | 588,805 | 600,317
Municipal securities |  |
AFS debt securities: |  |
Amortized Cost | 292,041 | 297,283
Gross Unrealized Gains | 97 | 75
Gross Unrealized Losses | (31,840) | (36,342)
Fair Value | 260,298 | 261,016
HTM debt securities: |  |
Amortized Cost | 188,002 | 188,872
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (39,767) | (43,081)
Fair Value | 148,235 | 145,791
Non-agency commercial mortgage-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 348,749 | 409,578
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (32,236) | (42,062)
Fair Value | 316,513 | 367,516
Non-agency residential mortgage-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 548,110 | 643,335
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (68,783) | (89,664)
Fair Value | 479,327 | 553,671
Corporate debt securities |  |
AFS debt securities: |  |
Amortized Cost | 653,501 | 653,501
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (121,682) | (151,076)
Fair Value | 531,819 | 502,425
Foreign government bonds |  |
AFS debt securities: |  |
Amortized Cost | 247,907 | 239,333
Gross Unrealized Gains | 1,671 | 69
Gross Unrealized Losses | (10,709) | (11,528)
Fair Value | 238,869 | 227,874
Asset-backed securities |  |
AFS debt securities: |  |
Amortized Cost | 36,195 | 43,234
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (460) | (934)
Fair Value | 35,735 | 42,300
Collateralized loan obligations (“CLOs”) |  |
AFS debt securities: |  |
Amortized Cost | 44,500 | 617,250
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (6) | (4,389)
Fair Value | $ 44,494 | $ 612,861

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