Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended	48 Months Ended	51 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Mar. 31, 2018
Income Tax Disclosure [Line Items]
Income Tax Expense (Benefit)	$ 126	$ 97
Tronox Litigation [Member] | Judicial Ruling [Member]
Income Tax Disclosure [Line Items]
Income Tax Expense (Benefit)				$ (346)	$ (346)
Unrecognized tax benefits	$ 1,200			$ 1,200	$ 1,200
Income tax refunds			$ 881