Stockholder Rights Plan (Details)	12 Months Ended
Dec. 31, 2014
Equity [Abstract]
Beneficial owner of common stock percentage	4.90%
Beneficial owner of common stock percentage in future	15.00%
Beneficial ownership percentage post standstill period	50.00%
Period of review of shareholder rights plan	3 years

Minimum percentage ownership that if acquired will allow current stockholders other than the triggering beneficial stockholder the right to purchase common stock at half the market price.

No definition available.

Name:	usg_BeneficialOwnerOfCommonStockPercentage
Namespace Prefix:	usg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant