Equity Method Investments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Schedule of Equity Method Investments [Line Items]
USG share of income from investment accounted for using the equity method	$ 12		$ 1		$ 20		$ 2
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Net sales	286				655	[1]
Gross profit	77				179	[1]
Operating profit	31				57	[1]
Net income	25				42	[1]
Net income attributable to USG Boral Building Products	24				39	[1]
USG share of income from investment accounted for using the equity method	12				19	[1]
Other equity method investments
Schedule of Equity Method Investments [Line Items]
USG share of income from investment accounted for using the equity method	$ 0	[2]	$ 1	[2]	$ 1	[2]	$ 2	[2]

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

[2] Amounts represent our share of income or loss from all equity method investments, other than UBBP. For the nine months ended September 30, 2014, the amount reflected includes two months of our share of equity method earnings from the joint ventures which we had accounted for as equity method investments prior to being contributed to UBBP on February 27, 2014.