Litigation	9 Months Ended
Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]
Litigation	Litigation CHINESE-MANUFACTURED DRYWALL LAWSUITS L&W Supply Corporation is one of many defendants in lawsuits relating to Chinese-made wallboard installed in homes primarily in the southeastern United States during 2006 and 2007. The plaintiffs in these lawsuits, most of whom are homeowners, seek damages associated with the removal and replacement of the Chinese-made wallboard which they claim emits elevated levels of sulfur gases causing a bad smell and corrosion of metal surfaces. Most of the lawsuits against L&W Supply Corporation are part of the multi-district class action litigation titled In re Chinese-Manufactured Drywall Products Liability Litigation, MDL No. 2047, pending in New Orleans, Louisiana. The vast majority of the claims against L&W Supply Corporation relate to wallboard we delivered that was manufactured by Knauf Plasterboard (Tianjin) Co., or Knauf Tianjin, an affiliate of a multi-national manufacturer of building materials that also beneficially owns approximately 14% of USG's outstanding shares of common stock. We have reached settlement agreements with Knauf and the plaintiffs in the multi-district class action litigation that cap our responsibility for all claims against us for homes to which we delivered Knauf Tianjin wallboard. As of September 30, 2013, we have an accrual of $6 million for our estimated cost of resolving all Chinese wallboard property damage claims pending against us and expected to be asserted in the future, and, based on the terms of our settlement with Knauf, we have a related receivable of $2 million recorded as an offset to the accrual. Our accrual does not take into account litigation costs, which are expensed as incurred, or any set-off for potential insurance recoveries. Based on the information available to us to date regarding the number and type of pending claims, estimates of likely future claims, and the estimated costs of resolving those claims, we believe that we have appropriately accrued for our exposure related to the Chinese wallboard claims, and we believe that these claims and other similar claims that might be asserted will not have a material effect on our results of operations, financial position or cash flows. WALLBOARD PRICING CLASS ACTION LAWSUITS Beginning December 2012, USG Corporation and United States Gypsum Company were named as defendants in putative class action lawsuits alleging that since at least September 2011, U.S. wallboard manufacturers conspired to fix and raise the price of gypsum wallboard sold in the United States and to effectuate the alleged conspiracy by ending the practice of providing job quotes on wallboard. These lawsuits are consolidated for pretrial proceedings in multi-district litigation in the United States District Court for the Eastern District of Pennsylvania, under the title In re: Domestic Drywall Antitrust Litigation, MDL No. 2437. Two consolidated complaints have been filed. One group of plaintiffs purports to represent a class of entities that purchased gypsum wallboard in the United States directly from any of the defendants or their affiliates from January 1, 2012 to the present. On behalf of this alleged direct purchaser class, the plaintiffs seek unspecified monetary damages, tripled under the antitrust laws, as well as pre-judgment interest, post-judgment interest and attorneys' fees. The second group of plaintiffs purports to bring their claims and seek damages on behalf of indirect purchasers of gypsum wallboard. These indirect purchaser plaintiffs seek to certify a separate class of persons or entities who from January 1, 2012 through the present indirectly purchased wallboard in the United States from the defendants or their affiliates for end use and not for resale. Recently, similar lawsuits were filed in Quebec and Ontario courts on behalf of purchasers of wallboard in Canada. These Canadian lawsuits also name as a defendant CGC Inc., a wholly owned subsidiary of USG Corporation, as well as other Canadian and U.S. wallboard manufacturers. These wallboard pricing class action lawsuits are still in a preliminary stage. However, based on the information known to us, we believe these lawsuits will not have a material effect on our results of operations, financial position or cash flows. ENVIRONMENTAL LITIGATION We have been notified by state and federal environmental protection agencies of possible involvement as one of numerous “potentially responsible parties” in a number of Superfund sites in the United States. As a potentially responsible party, we may be responsible to pay for some part of the cleanup of hazardous waste at those sites. In most of these sites, our involvement is expected to be minimal. In addition, we are involved in environmental cleanups of other property that we own or owned. As of September 30, 2013, we have an accrual of $18 million for our probable and reasonably estimable liability in connection with these matters. Our accruals take into account all known or estimated undiscounted costs associated with these sites, including site investigations and feasibility costs, site cleanup and remediation, certain legal costs, and fines and penalties, if any. However, we continue to review these accruals as additional information becomes available and revise them as appropriate. Based on the information known to us, we believe these environmental matters will not have a material effect on our results of operations, financial position or cash flows. OTHER LITIGATION We are named as defendants in other claims and lawsuits arising from our operations, including claims and lawsuits arising from the operation of our vehicles, product warranties, personal injury and commercial disputes. We believe that we have properly accrued for our probable liability in connection with these claims and suits, taking into account the probability of liability, whether our exposure can be reasonably estimated and, if so, our estimate of our liability or the range of our liability. We do not expect these or any other litigation matters involving USG to have a material effect on our results of operations, financial position or cash flows.

Litigation

CHINESE-MANUFACTURED DRYWALL LAWSUITS

L&W Supply Corporation is one of many defendants in lawsuits relating to Chinese-made wallboard installed in homes primarily in the southeastern United States during 2006 and 2007. The plaintiffs in these lawsuits, most of whom are homeowners, seek damages associated with the removal and replacement of the Chinese-made wallboard which they claim emits elevated levels of sulfur gases causing a bad smell and corrosion of metal surfaces. Most of the lawsuits against L&W Supply Corporation are part of the multi-district class action litigation titled In re Chinese-Manufactured Drywall Products Liability Litigation, MDL No. 2047, pending in New Orleans, Louisiana.

The vast majority of the claims against L&W Supply Corporation relate to wallboard we delivered that was manufactured by Knauf Plasterboard (Tianjin) Co., or Knauf Tianjin, an affiliate of a multi-national manufacturer of building materials that also beneficially owns approximately 14% of USG's outstanding shares of common stock. We have reached settlement agreements with Knauf and the plaintiffs in the multi-district class action litigation that cap our responsibility for all claims against us for homes to which we delivered Knauf Tianjin wallboard.

As of September 30, 2013, we have an accrual of $6 million for our estimated cost of resolving all Chinese wallboard property damage claims pending against us and expected to be asserted in the future, and, based on the terms of our settlement with Knauf, we have a related receivable of $2 million recorded as an offset to the accrual. Our accrual does not take into account litigation costs, which are expensed as incurred, or any set-off for potential insurance recoveries. Based on the information available to us to date regarding the number and type of pending claims, estimates of likely future claims, and the estimated costs of resolving those claims, we believe that we have appropriately accrued for our exposure related to the Chinese wallboard claims, and we believe that these claims and other similar claims that might be asserted will not have a material effect on our results of operations, financial position or cash flows.

WALLBOARD PRICING CLASS ACTION LAWSUITS

Beginning December 2012, USG Corporation and United States Gypsum Company were named as defendants in putative class action lawsuits alleging that since at least September 2011, U.S. wallboard manufacturers conspired to fix and raise the price of gypsum wallboard sold in the United States and to effectuate the alleged conspiracy by ending the practice of providing job quotes on wallboard. These lawsuits are consolidated for pretrial proceedings in multi-district litigation in the United States District Court for the Eastern District of Pennsylvania, under the title In re: Domestic Drywall Antitrust Litigation, MDL No. 2437. Two consolidated complaints have been filed. One group of plaintiffs purports to represent a class of entities that purchased gypsum wallboard in the United States directly from any of the defendants or their affiliates from January 1, 2012 to the present. On behalf of this alleged direct purchaser class, the plaintiffs seek unspecified monetary damages, tripled under the antitrust laws, as well as pre-judgment interest, post-judgment interest and attorneys' fees. The second group of plaintiffs purports to bring their claims and seek damages on behalf of indirect purchasers of gypsum wallboard. These indirect purchaser plaintiffs seek to certify a separate class of persons or entities who from January 1, 2012 through the present indirectly purchased wallboard in the United States from the defendants or their affiliates for end use and not for resale. Recently, similar lawsuits were filed in Quebec and Ontario courts on behalf of purchasers of wallboard in Canada. These Canadian lawsuits also name as a defendant CGC Inc., a wholly owned subsidiary of USG Corporation, as well as other Canadian and U.S. wallboard manufacturers. These wallboard pricing class action lawsuits are still in a preliminary stage. However, based on the information known to us, we believe these lawsuits will not have a material effect on our results of operations, financial position or cash flows.

ENVIRONMENTAL LITIGATION

We have been notified by state and federal environmental protection agencies of possible involvement as one of numerous “potentially responsible parties” in a number of Superfund sites in the United States. As a potentially responsible party, we may be responsible to pay for some part of the cleanup of hazardous waste at those sites. In most of these sites, our involvement is expected to be minimal. In addition, we are involved in environmental cleanups of other property that we own or owned. As of September 30, 2013, we have an accrual of $18 million for our probable and reasonably estimable liability in connection with these matters. Our accruals take into account all known or estimated undiscounted costs associated with these sites, including site investigations and feasibility costs, site cleanup and remediation, certain legal costs, and fines and penalties, if any. However, we continue to review these accruals as additional information becomes available and revise them as appropriate. Based on the information known to us, we believe these environmental matters will not have a material effect on our results of operations, financial position or cash flows.

OTHER LITIGATION

We are named as defendants in other claims and lawsuits arising from our operations, including claims and lawsuits arising from the operation of our vehicles, product warranties, personal injury and commercial disputes. We believe that we have properly accrued for our probable liability in connection with these claims and suits, taking into account the probability of liability, whether our exposure can be reasonably estimated and, if so, our estimate of our liability or the range of our liability. We do not expect these or any other litigation matters involving USG to have a material effect on our results of operations, financial position or cash flows.