Income Taxes - Components of Income Tax Expense Attributable to Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current expense:
Federal and state	$ 0	$ 11	$ 17
Foreign	244	248	233
Total	244	259	250
Deferred (benefit) expense:
Federal and state	(161)	(109)	(170)
Foreign	(11)	(34)	(21)
Total	(172)	(143)	(191)
Income tax expense (benefit)	$ 72	$ 116	$ 59