Equity Method Investments (Details 1) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of Equity Method Investments [Line Items]
Changes in AOCI - foreign currency translation	$ (5)	$ 15	$ (39)	$ 11
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Changes in AOCI - foreign currency translation	$ (3)	$ 10	$ (19)	$ 11