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Comprehensive Income - Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income (Detail) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2024 | Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning balance, before tax | $ (616) | $ (1,066)
Unrealized holding gains (losses), net, before tax | (13) | 89
Foreign currency translation adjustment, before tax | (2) | 2
Unrealized losses on cash flow hedges | (243) | 51
Total other comprehensive income (loss) before reclassifications, before tax | (258) | 142
Losses realized in net income | 1 |
Net yield adjustment from cash flow hedges currently in effect, before tax | 87 | 59
Amortization of actuarial losses, before tax | (1) | (2)
Total other comprehensive income (loss), before tax | (171) | 199
Ending balance, before tax | (787) | (867)
Beginning balance, tax | 157 | 276
Unrealized holding gains (losses), net, tax | 2 | (24)
Foreign currency translation adjustment, tax |  | (1)
Unrealized losses on cash flow hedges, tax | 60 | (13)
Total other comprehensive income (loss) before reclassifications, tax | 62 | (38)
Net yield adjustment from cash flow hedges currently in effect, tax | (21) | (16)
Total other comprehensive income (loss), tax | 41 | (54)
Ending balance, tax | 198 | 222
Beginning balance, net of tax | (459) | (790)
Unrealized holding gains (losses), net of tax | (11) | 65
Foreign currency translation adjustments, net of tax | (2) | 1
Unrealized losses on cash flow hedges, net of tax | (183) | 38
Total other comprehensive income (loss) before reclassifications, net of tax | (196) | 104
Losses realized in net income, net of tax | 1 |
Net yield adjustment from cash flow hedges currently in effect, net of tax | 66 | 43
Amortization of actuarial losses, net of tax | (1) | (2)
Total other comprehensive income (loss) | (130) | 145
Ending balance, net of tax | (589) | (645)
Cash Flow Hedges [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning balance, before tax | (203) | (336)
Unrealized losses on cash flow hedges | (243) | 51
Total other comprehensive income (loss) before reclassifications, before tax | (243) | 51
Net yield adjustment from cash flow hedges currently in effect, before tax | 87 | 59
Total other comprehensive income (loss), before tax | (156) | 110
Ending balance, before tax | (359) | (226)
Total other comprehensive income (loss) | (117) |
Defined Benefit Plans [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning balance, before tax | (155) | (273)
Amortization of actuarial losses, before tax | (1) | (2)
Total other comprehensive income (loss), before tax | (1) | (2)
Ending balance, before tax | (156) | (275)
Total other comprehensive income (loss) | (1) |
Other [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning balance, before tax | (7) | (13)
Foreign currency translation adjustment, before tax | (2) | 2
Total other comprehensive income (loss) before reclassifications, before tax | (2) | 2
Total other comprehensive income (loss), before tax | (2) | 2
Ending balance, before tax | (9) | (11)
Investment Securities [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Beginning balance, before tax | (251) | (444)
Unrealized holding gains (losses), net, before tax | (13) | 89
Total other comprehensive income (loss) before reclassifications, before tax | (13) | 89
Losses realized in net income | 1 |
Total other comprehensive income (loss), before tax | (12) | 89
Ending balance, before tax | (263) | $ (355)
Total other comprehensive income (loss) | $ (10) |

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