Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Taxes
Effective tax rate of income (loss) before income taxes	23.90%	24.20%	21.30%	23.90%
Tax credits and adjustments	$ 37	$ 2	$ 74	$ 4
Investment proportional amortization	37		37
Income tax benefit from low-income housing investments	22	26	50	48
Variable interest entities interest expense	5	3	11	7
Equity in net losses of unconsolidated entities	$ (22)	12	$ (3)	23
Low income housing investments [Member]
Income Taxes
Equity in net losses of unconsolidated entities		$ 12		$ 25