Income Taxes - Reconciliation of Unrecognized Tax Benefits (Excluding Interest and Penalties) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 5	$ 5	$ 4
Additions for tax positions of prior years	0	0	2
Reductions for tax positions of prior years	(1)	0	0
Expiration of the statute of limitations	0	0	(1)
Balance at end of year	$ 4	$ 5	$ 5