Equity Method Investments (Details 2) - 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]
USG share of income from investment accounted for using the equity method	$ 14	$ 5	$ 22	$ 8
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Gross profit	70	80	131	102	[1]
Net income from continuing operations	28	10	46	17	[1]
Net income	28	10	46	17	[1]
Net income attributable to USG Boral Building Products	26	9	42	15	[1]
USG share of income from investment accounted for using the equity method	13	4	21	7	[1]
Other equity method investments
Schedule of Equity Method Investments [Line Items]
USG share of income from investment accounted for using the equity method	1	1	1	1
USG Boral Building Products | USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Net sales	264	280	492	369	[1]
Operating profit	$ 34	$ 16	$ 57	$ 26	[1]

[1] Operating results are presented for UBBP for the four months ended June 30, 2014.