Organization, Consolidation and Presentation of Financial Statements	9 Months Ended
Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements	Organization, Consolidation and Presentation of Financial Statements PREPARATION OF FINANCIAL STATEMENTS We prepared the accompanying unaudited 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, or U.S. GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. Actual results could differ materially from those estimates. In the opinion of our management, the financial statements reflect all adjustments, which are of a normal recurring nature, necessary for a fair presentation of our financial results for the interim periods. The results of operations for the three and nine months ended September 30, 2015 are not necessarily indicative of the results of operations to be expected for the entire year. Our investments with Boral Limited in the 50/50 joint ventures, USG Boral Building Products or UBBP, commenced on February 27, 2014, and as a result, seven months of results of UBBP were recorded in our accompanying consolidated statement of operations for the nine months ended September 30, 2014. See Note 2 for further description of our investment in UBBP. Our segments are structured around our key products and business units: Gypsum, Ceilings, Distribution and UBBP. Our Gypsum reportable segment is an aggregation of the operating segments of the gypsum businesses in the United States, Canada, Mexico, and Latin America, our mining operation in Little Narrows, Nova Scotia, Canada, and our shipping company, which we have exited. Gypsum manufactures products throughout the United States, Canada, and Mexico. These products include USG Sheetrock^® brand gypsum wallboard and related products including Sheetrock^®brand joint compound, Durock^® brand cement board, Levelrock^® brand gypsum underlayment, Fiberock^® brand gypsum fiber panels, and Securock^®brand glass mat sheathing used for building exteriors and gypsum fiber and glass mat panels used as roof cover board. Our Ceilings reportable segment is an aggregation of the operating segments of the ceilings businesses in the United States, Canada, Mexico, Latin America and, through February 27, 2014, the businesses in the Asia-Pacific region. Ceilings manufactures ceiling tile in the United States and ceiling grid in the United States, Canada and, through February 27, 2014, the Asia-Pacific region. Distribution delivers gypsum wallboard, drywall metal, ceilings products, joint compound and other building products throughout the United States. UBBP manufactures, distributes and sells certain building products, mines raw gypsum and sells natural and synthetic gypsum throughout Asia, Australasia and the Middle East. 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, 2014, which we filed with the SEC on February 12, 2015. RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS In July 2015, the Financial Accounting Standards Board, or FASB, issued Accounting Standard Update, or ASU, 2015-11, "Simplifying the Measurement of Inventory", which changes the measurement principle for inventory from the lower of cost or market to the lower of cost or net realizable value for entities that measure inventory using the first-in, first-out (FIFO) or average cost method. The ASU defines net realizable value as estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The standard will be effective for us in the first quarter of 2017, with early adoption permitted. We are evaluating the effect of adopting this standard, but we do not expect the adoption of ASU 2015-11 will have a significant impact to our consolidated financial statements or disclosures. In May 2015, the FASB issued ASU 2015-07, "Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent)," which updates the disclosure requirements for investments that are measured at net asset value using the practical expedient. These investments are to be removed from the fair value hierarchy and shown as a reconciling item. The standard will be effective for us in the first quarter of 2016, with early adoption permitted. We do not expect that the adoption of ASU 2015-07 will have a significant impact to our consolidated financial statements or disclosures. In April 2015, the FASB issued ASU 2015-03, "Simplifying the Presentation of Debt Issuance Costs", which requires costs related to a recognized debt liability to be presented on the balance sheet as a direct deduction from the debt liability rather than as an asset. In August 2015, the FASB issued ASU 2015-15, "Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements", which clarifies that the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset, regardless of whether there are any outstanding borrowings on the line-of-credit. The standards will be effective for us in the first quarter of 2016, with early adoption permitted. We plan to early adopt the standards as of December 31, 2015. Upon adoption, we would reclassify our deferred debt issuance costs associated with our long-term debt other than our line-of-credit from other assets to long term debt. If adopted as of September 30, 2015, we would have recorded a reduction in both other assets and long-term debt of $14 million and would have provided additional disclosure. In August 2014, the FASB issued ASU 2014-15, "Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern," which requires management to assess, at each annual and interim reporting period, the entity's ability to continue as a going concern within one year of date of the financial statements are issued and provide related disclosures. The new standard will be effective for us for the year ended December 31, 2016, with early adoption permitted. We do not expect that the adoption of ASU 2014-15 will have a significant impact to our consolidated financial statements or disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605),” and requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. There are two transition methods available under the new standard, either cumulative effect or retrospective. In August 2015, the FASB issued ASU 2015-14 which defers the mandatory effective date by one year. The standard will be effective for us in the first quarter of 2018, with early adoption permitted, but not before the original effective date. We will adopt the new standard using the modified retrospective approach, which requires the standard be applied only to the most current period presented, with the cumulative effect of initially applying the standard recognized at the date of initial application. We do not expect that the adoption of ASU 2014-09 will have a significant impact to our consolidated financial statements or disclosures.

Organization, Consolidation and Presentation of Financial Statements

PREPARATION OF FINANCIAL STATEMENTS

We prepared the accompanying unaudited 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, or U.S. GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. Actual results could differ materially from those estimates. In the opinion of our management, the financial statements reflect all adjustments, which are of a normal recurring nature, necessary for a fair presentation of our financial results for the interim periods. The results of operations for the three and nine months ended September 30, 2015 are not necessarily indicative of the results of operations to be expected for the entire year.

Our investments with Boral Limited in the 50/50 joint ventures, USG Boral Building Products or UBBP, commenced on February 27, 2014, and as a result, seven months of results of UBBP were recorded in our accompanying consolidated statement of operations for the nine months ended September 30, 2014. See Note 2 for further description of our investment in UBBP.

Our segments are structured around our key products and business units: Gypsum, Ceilings, Distribution and UBBP.

Our Gypsum reportable segment is an aggregation of the operating segments of the gypsum businesses in the United States, Canada, Mexico, and Latin America, our mining operation in Little Narrows, Nova Scotia, Canada, and our shipping company, which we have exited. Gypsum manufactures products throughout the United States, Canada, and Mexico. These products include USG Sheetrock^® brand gypsum wallboard and related products including Sheetrock^®brand joint compound, Durock^® brand cement board, Levelrock^® brand gypsum underlayment, Fiberock^® brand gypsum fiber panels, and Securock^®brand glass mat sheathing used for building exteriors and gypsum fiber and glass mat panels used as roof cover board.

Our Ceilings reportable segment is an aggregation of the operating segments of the ceilings businesses in the United States, Canada, Mexico, Latin America and, through February 27, 2014, the businesses in the Asia-Pacific region. Ceilings manufactures ceiling tile in the United States and ceiling grid in the United States, Canada and, through February 27, 2014, the Asia-Pacific region.

Distribution delivers gypsum wallboard, drywall metal, ceilings products, joint compound and other building products throughout the United States.

UBBP manufactures, distributes and sells certain building products, mines raw gypsum and sells natural and synthetic gypsum throughout Asia, Australasia and the Middle East.

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, 2014, which we filed with the SEC on February 12, 2015.

RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS

In July 2015, the Financial Accounting Standards Board, or FASB, issued Accounting Standard Update, or ASU, 2015-11, "Simplifying the Measurement of Inventory", which changes the measurement principle for inventory from the lower of cost or market to the lower of cost or net realizable value for entities that measure inventory using the first-in, first-out (FIFO) or average cost method. The ASU defines net realizable value as estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The standard will be effective for us in the first quarter of 2017, with early adoption permitted. We are evaluating the effect of adopting this standard, but we do not expect the adoption of ASU 2015-11 will have a significant impact to our consolidated financial statements or disclosures.

In May 2015, the FASB issued ASU 2015-07, "Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent)," which updates the disclosure requirements for investments that are measured at net asset value using the practical expedient. These investments are to be removed from the fair value hierarchy and shown as a reconciling item. The standard will be effective for us in the first quarter of 2016, with early adoption permitted. We do not expect that the adoption of ASU 2015-07 will have a significant impact to our consolidated financial statements or disclosures.

In April 2015, the FASB issued ASU 2015-03, "Simplifying the Presentation of Debt Issuance Costs", which requires costs related to a recognized debt liability to be presented on the balance sheet as a direct deduction from the debt liability rather than as an asset. In August 2015, the FASB issued ASU 2015-15, "Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements", which clarifies that the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset, regardless of whether there are any outstanding borrowings on the line-of-credit. The standards will be effective for us in the first quarter of 2016, with early adoption permitted. We plan to early adopt the standards as of December 31, 2015. Upon adoption, we would reclassify our deferred debt issuance costs associated with our long-term debt other than our line-of-credit from other assets to long term debt. If adopted as of September 30, 2015, we would have recorded a reduction in both other assets and long-term debt of $14 million and would have provided additional disclosure.

In August 2014, the FASB issued ASU 2014-15, "Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern," which requires management to assess, at each annual and interim reporting period, the entity's ability to continue as a going concern within one year of date of the financial statements are issued and provide related disclosures. The new standard will be effective for us for the year ended December 31, 2016, with early adoption permitted. We do not expect that the adoption of ASU 2014-15 will have a significant impact to our consolidated financial statements or disclosures.

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605),” and requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. There are two transition methods available under the new standard, either cumulative effect or retrospective. In August 2015, the FASB issued ASU 2015-14 which defers the mandatory effective date by one year. The standard will be effective for us in the first quarter of 2018, with early adoption permitted, but not before the original effective date. We will adopt the new standard using the modified retrospective approach, which requires the standard be applied only to the most current period presented, with the cumulative effect of initially applying the standard recognized at the date of initial application. We do not expect that the adoption of ASU 2014-09 will have a significant impact to our consolidated financial statements or disclosures.