2.2.0.7 false Preparation of Financial Statements 0201 - Disclosure - Preparation of Financial Statements true false false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 Preparation of Financial Statements [Abstract] 0 us-gaap_GeneralPoliciesAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 3 Preparation of Financial Statements 1 us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock us-gaap true na duration No definition available. false false false false false false false false false false false verboselabel false 1 false false false false 0 0     <div style="font-family: 'Times New Roman',Times,serif"> <div align="left" style="font-size: 10pt; margin-top: 0pt"><b></b> </div> <div align="left"> </div> <div align="left" style="font-size: 10pt; margin-top: 0pt"><b> </b> </div> <div align="left" style="font-size: 10pt; margin-top: 0pt"><i> </i> </div> <div align="left" style="font-size: 10pt; margin-top: 12pt"><b>1. Preparation of Financial Statements</b> </div> <div align="left" style="font-size: 10pt; margin-top: 6pt">We prepared the accompanying unaudited condensed consolidated financial statements of USG Corporation in accordance with applicable United States Securities and Exchange Commission, or SEC, guidelines pertaining to interim financial information. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. Actual results could differ from those estimates. In the opinion of our management, the financial statements reflect all adjustments, which are of a normal recurring nature except as noted, necessary for a fair presentation of our financial results for the interim periods. The results of operations for the three months and nine months ended September 30, 2010 are not necessarily indicative of the results of operations to be expected for the entire year. These financial statements and notes are to be read in conjunction with the financial statements and notes included in USG’s Annual Report on Form 10-K for the fiscal year ended December 31, 2009 which we filed with the SEC on February 12, 2010. </div> </div>  <!-- Begin Block Tagged Note false false false us-types:textBlockItemType textblock Description containing the entire organization, consolidation and basis of presentation of financial statements disclosure. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS140-4 and FIN46(R)-8 -Paragraph 8, C1, C7 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 2-6 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-6 -Paragraph 10 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Interpretation (FIN) -Number 46R -Paragraph 4, 14, 15 false 1 2 false UnKnown UnKnown UnKnown false true