Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Income tax benefit	$ (209)	$ (125)	$ (375)	$ (251)
Judicial Ruling [Member] | Tronox Litigation [Member]
Income Tax Disclosure [Line Items]
Income tax benefit			346		$ 346
Unrecognized tax benefits	$ 1,200		$ 1,200		$ 1,200
Income tax refunds						$ 881