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Significant Accounting Policies (Details 1) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Debt Instrument [Line Items]    
Disposal Group, Including Discontinued Operation, Assets, Current $ 5us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent $ 1us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent
10% convertible senior notes due 2018    
Debt Instrument [Line Items]    
Interest rate of convertible senior notes 10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= usg_TenPercentConvertibleSeniorNotesDueTwoThousandEighteenMember
10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= usg_TenPercentConvertibleSeniorNotesDueTwoThousandEighteenMember