Earnings (Loss) Per Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations Attributable to Parent									$ (183)
Loss from continuing operations	(64)	(30)	(59)	(29)	(100)	(117)	(72)	(107)	(182)	(396)	(410)
Income (loss) from discontinued operations, net of tax	(3)	1	2	2	0	2	2	2	2	6	5
Gain on sale of discontinued operations, net of tax	55								55	0	0
Net loss attributable to USG	$ (13)	$ (29)	$ (57)	$ (27)	$ (100)	$ (115)	$ (70)	$ (105)	$ (126)	$ (390)	$ (405)
Shares, Basic									106,382,934	103,902,038	100,471,635
Shares, Diluted									106,382,934	103,902,038	100,471,635
Loss from continuing operations per basic share	$ (0.59)	$ (0.29)	$ (0.55)	$ (0.28)	$ (0.95)	$ (1.11)	$ (0.70)	$ (1.03)	$ (1.72)	$ (3.81)	$ (4.08)
Income from discontinued operations per basic share									$ 0.53	$ 0.05	$ 0.05
Basic loss per common share									$ (1.19)	$ (3.76)	$ (4.03)
Loss from continuing operations per diluted share	$ (0.59)	$ (0.29)	$ (0.55)	$ (0.28)	$ (0.95)	$ (1.11)	$ (0.70)	$ (1.03)	$ (1.72)	$ (3.81)	$ (4.08)
Income from discontinued operations per diluted share									$ 0.53	$ 0.05	$ 0.05
Diluted loss per common share									$ (1.19)	$ (3.76)	$ (4.03)