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Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss) (Tables) | 9 Months Ended
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Sep. 30, 2025
Other Comprehensive Income And Accumulated Other Comprehensive Income Disclosure [Abstract] |
Changes in accumulated other comprehensive income (loss) (AOCI) [Table Text Block] | The following tables present the changes in the Company’s accumulated other comprehensive income (loss) (AOCI) for the three and nine months ended September 30, 2025.
|  | Changes in Net Unrealized Gains (Losses) on Investment Securities |  |  |  |  |  |
(in millions) |  | Having No Credit Losses Recognized in the Consolidated Statement of Income |  | Having Credit Losses Recognized in the Consolidated Statement of Income |  | Net Benefit Plan Assets and Obligations Recognized in Shareholders’ Equity |  | Net Unrealized Foreign Currency Translation |  | Total Accumulated Other Comprehensive Income (Loss)
Balance, June 30, 2025 |  | $ | (3,216) |  |  | $ | 185 |  |  | $ | (224) |  |  | $ | (830) |  |  | $ | (4,085) |
Other comprehensive income (loss) (OCI) before reclassifications, net of tax |  | 1,059 |  |  | — |  |  | — |  |  | (70) |  |  | 989 |
Amounts reclassified from AOCI, net of tax |  | 2 |  |  | — |  |  | — |  |  | — |  |  | 2 |
Net OCI, current period |  | 1,061 |  |  | — |  |  | — |  |  | (70) |  |  | 991 |
Balance, September 30, 2025 |  | $ | (2,155) |  |  | $ | 185 |  |  | $ | (224) |  |  | $ | (900) |  |  | $ | (3,094) |
|  | Changes in Net Unrealized Gains (Losses) on Investment Securities |  |  |  |  |  |
(in millions) |  | Having No Credit Losses Recognized in the Consolidated Statement of Income |  | Having Credit Losses Recognized in the Consolidated Statement of Income |  | Net Benefit Plan Assets and Obligations Recognized in Shareholders’ Equity |  | Net Unrealized Foreign Currency Translation |  | Total Accumulated Other Comprehensive Income (Loss)
Balance, December 31, 2024 |  | $ | (3,824) |  |  | $ | 184 |  |  | $ | (224) |  |  | $ | (1,103) |  |  | $ | (4,967) |
Other comprehensive income (loss) (OCI) before reclassifications, net of tax |  | 1,629 |  |  | 1 |  |  | — |  |  | 203 |  |  | 1,833 |
Amounts reclassified from AOCI, net of tax |  | 40 |  |  | — |  |  | — |  |  | — |  |  | 40 |
Net OCI, current period |  | 1,669 |  |  | 1 |  |  | — |  |  | 203 |  |  | 1,873 |
Balance, September 30, 2025 |  | $ | (2,155) |  |  | $ | 185 |  |  | $ | (224) |  |  | $ | (900) |  |  | $ | (3,094) |
Pre-tax components of other comprehensive income (loss) and the related income tax expense (benefit) for each component [Table Text Block] | The following table presents the pre-tax components of the Company’s other comprehensive income (loss) and the related income tax expense (benefit).
|  | Three Months Ended September 30, |  | Nine Months Ended September 30,
(in millions) |  | 2025 |  | 2024 |  | 2025 |  | 2024
Changes in net unrealized gains (losses) on investment securities: |  |  |  |  |  |  |  |
Having no credit losses recognized in the consolidated statement of income |  | $ | 1,347 |  |  | $ | 2,370 |  |  | $ | 2,124 |  |  | $ | 1,294 |
Income tax expense |  | 286 |  |  | 506 |  |  | 455 |  |  | 279 |
Net of taxes |  | 1,061 |  |  | 1,864 |  |  | 1,669 |  |  | 1,015 |
Having credit losses recognized in the consolidated statement of income |  | — |  |  | 1 |  |  | 1 |  |  | 4 |
Income tax expense |  | — |  |  | — |  |  | — |  |  | 1 |
Net of taxes |  | — |  |  | 1 |  |  | 1 |  |  | 3 |
Net changes in benefit plan assets and obligations |  | — |  |  | (1) |  |  | — |  |  | (4) |
Income tax benefit |  | — |  |  | — |  |  | — |  |  | (1) |
Net of taxes |  | — |  |  | (1) |  |  | — |  |  | (3) |
Net changes in unrealized foreign currency translation |  | (72) |  |  | 120 |  |  | 217 |  |  | 24 |
Income tax expense (benefit) |  | (2) |  |  | 7 |  |  | 14 |  |  | 1 |
Net of taxes |  | (70) |  |  | 113 |  |  | 203 |  |  | 23 |
Total other comprehensive income |  | 1,275 |  |  | 2,490 |  |  | 2,342 |  |  | 1,318 |
Total income tax expense |  | 284 |  |  | 513 |  |  | 469 |  |  | 280 |
Total other comprehensive income, net of taxes |  | $ | 991 |  |  | $ | 1,977 |  |  | $ | 1,873 |  |  | $ | 1,038 |
Pre-tax and related income tax (expense) benefit components of the amounts reclassified from AOCI to the consolidated statement of income [Table Text Block] | The following table presents the pre-tax and related income tax (expense) benefit components of the amounts reclassified from the Company’s AOCI to the Company’s consolidated statement of income.
|  | Three Months Ended September 30, |  | Nine Months Ended September 30,
(in millions) |  | 2025 |  | 2024 |  | 2025 |  | 2024
Reclassification adjustments related to unrealized gains (losses) on investment securities: |  |  |  |  |  |  |  |
Having no credit losses recognized in the consolidated statement of income (1) |  | $ | 2 |  |  | $ | 17 |  |  | $ | 50 |  |  | $ | 92 |
Income tax benefit (2) |  | — |  |  | 3 |  |  | 10 |  |  | 19 |
Net of taxes |  | 2 |  |  | 14 |  |  | 40 |  |  | 73 |
Having credit losses recognized in the consolidated statement of income (1) |  | — |  |  | — |  |  | — |  |  | — |
Income tax benefit (2) |  | — |  |  | — |  |  | — |  |  | — |
Net of taxes |  | — |  |  | — |  |  | — |  |  | — |
Reclassification adjustment related to benefit plan assets and obligations: |  |  |  |  |  |  |  |
Claims and claim adjustment expenses (benefit) (3) |  | — |  |  | — |  |  | — |  |  | (1) |
General and administrative expenses (benefit) (3) |  | — |  |  | (1) |  |  | — |  |  | (3) |
Total |  | — |  |  | (1) |  |  | — |  |  | (4) |
Income tax expense (2) |  | — |  |  | (1) |  |  | — |  |  | (1) |
Net of taxes |  | — |  |  | — |  |  | — |  |  | (3) |
Reclassification adjustment related to foreign currency translation (1) |  | — |  |  | — |  |  | — |  |  | — |
Income tax benefit (2) |  | — |  |  | — |  |  | — |  |  | — |
Net of taxes |  | — |  |  | — |  |  | — |  |  | — |
Total reclassifications |  | 2 |  |  | 16 |  |  | 50 |  |  | 88 |
Total income tax benefit |  | — |  |  | 2 |  |  | 10 |  |  | 18 |
Total reclassifications, net of taxes |  | $ | 2 |  |  | $ | 14 |  |  | $ | 40 |  |  | $ | 70 |
_________________________________________________________ (1)(Increases) decreases net realized investment gains (losses) on the consolidated statement of income. (2)(Increases) decreases income tax expense on the consolidated statement of income. (3)Increases (decreases) expenses on the consolidated statement of income.

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