Equity Method Investments - Translation Gains or Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Equity Method Investments [Line Items]
Translation gain	$ 12	$ 40
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Translation gain	$ 3	$ 24