Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Cash held by subsidiaries contributed to joint venture	$ 23
10% convertible senior notes due 2018
Converted debt aggregate principal amount	$ 75	$ 325

Cash held by subsidiaries contributed to joint venture, considered part of consideration paid for investment in joint venture

No definition available.

Name:	usg_Cashheldbysubsidiariescontributedtojointventure
Namespace Prefix:	usg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration