Equity Method Investments - Translation Gains and Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Translation (loss) gain	$ (40)	$ 58	$ (53)
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Translation (loss) gain	$ (31)	$ 40	$ (30)