Equity Method Investments (Details 1) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Equity Method Investments [Line Items]
Changes in AOCI - foreign currency translation	$ (52)	$ (39)	$ (91)	$ (28)
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Changes in AOCI - foreign currency translation	$ (35)	$ (24)	$ (54)	$ (13)