Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Taxes
Effective tax rate of income (loss) before income taxes	21.70%	23.90%	20.50%	21.30%
Tax credits and adjustments	$ 43	$ 37	$ 89	$ 74
Low income housing investments [Member]
Income Taxes
Investment proportional amortization tax impact	25	37	45	37
Income tax benefit from low-income housing investments	35	22	62	50
Variable interest entities interest expense	$ 8	$ 5	$ 17	$ 11

Amount, before amortization expense, of income tax credit and other tax benefit generated by investment under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under tax credit program not meeting condition for accounting under proportional amortization method.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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A credit or adjustment for government or taxing authority authorized decrease in taxes owed as a result of meeting certain tax policy conditions.

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Interest expense on beneficial interests issued by consolidated variable interest entities.

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Amount of income tax credit generated by investment under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under tax credit program not meeting condition for accounting under proportional amortization method.

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Income Taxes [Line Items]

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