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Equity Method Investments (Schedule of Investments) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Feb. 27, 2014
Schedule of Equity Method Investments [Line Items]      
Equity method investments $ 735us-gaap_EquityMethodInvestments $ 73us-gaap_EquityMethodInvestments  
Minimum      
Schedule of Equity Method Investments [Line Items]      
Ownership percentage interest 20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_RangeAxis
= us-gaap_MinimumMember		    
Maximum      
Schedule of Equity Method Investments [Line Items]      
Ownership percentage interest 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_RangeAxis
= us-gaap_MaximumMember		    
USG Boral Building Products      
Schedule of Equity Method Investments [Line Items]      
Equity method investments 689us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= usg_USGBoralBuildingProductsMember		   676us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= usg_USGBoralBuildingProductsMember
Ownership percentage interest 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= usg_USGBoralBuildingProductsMember		    
Other equity method investments      
Schedule of Equity Method Investments [Line Items]      
Equity method investments $ 46us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= us-gaap_EquityMethodInvestmentsMember		 $ 73us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= us-gaap_EquityMethodInvestmentsMember		  
Other equity method investments | Minimum      
Schedule of Equity Method Investments [Line Items]      
Ownership percentage interest 33.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= us-gaap_EquityMethodInvestmentsMember		 33.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= us-gaap_EquityMethodInvestmentsMember		  
Other equity method investments | Maximum      
Schedule of Equity Method Investments [Line Items]      
Ownership percentage interest 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= us-gaap_EquityMethodInvestmentsMember		 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= us-gaap_EquityMethodInvestmentsMember