Debt (Details) In Millions, except Share data, unless otherwise specified	6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended
	Jun. 30, 2011 USD ($)	Dec. 31, 2010 USD ($)	Jun. 30, 2011 6.3% senior notes due 2016 [Member] USD ($)	Dec. 31, 2010 6.3% senior notes due 2016 [Member] USD ($)	Jun. 30, 2011 7.75% senior notes due 2018, net of discount [Member] USD ($)	Dec. 31, 2010 7.75% senior notes due 2018, net of discount [Member] USD ($)	Jun. 30, 2011 8.375% senior notes due 2018 [Member] USD ($)	Dec. 31, 2010 8.375% senior notes due 2018 [Member] USD ($)	Jun. 30, 2011 9.75% senior notes due 2014, net of discount [Member] USD ($)	Dec. 31, 2010 9.75% senior notes due 2014, net of discount [Member] USD ($)	Jun. 30, 2011 10% convertible senior notes due 2018, net of discount [Member] USD ($)	Dec. 31, 2010 10% convertible senior notes due 2018, net of discount [Member] USD ($)	Jun. 30, 2011 Ship mortgage facility (includes $7 million of current portion of long-term debt) [Member] USD ($)	Dec. 31, 2010 Ship mortgage facility (includes $7 million of current portion of long-term debt) [Member] USD ($)	Jun. 30, 2011 Industrial revenue bonds (due 2028 through 2034) [Member] USD ($)	Dec. 31, 2010 Industrial revenue bonds (due 2028 through 2034) [Member] USD ($)	Jun. 30, 2011 CGC Credit Facility CAD [Member] CAD
Total debt, including the current portion of long-term debt
Total debt	$ 2,306	$ 2,308	$ 500	$ 500	$ 499	$ 499	$ 350	$ 350	$ 296	$ 296	$ 382	$ 382	$ 40	$ 42	$ 239	$ 239
Debt (Textuals) [Abstract]
Interest rate of senior notes	10.00%		6.30%	6.30%	7.75%	7.75%	8.375%	8.375%	9.75%	9.75%	10.00%	10.00%
Variable interest rate, LIBOR plus													1.65%
Aggregate principal amount	400		500		500		350		300		400						30
Debt discount					1				4		18
Maximum interest rate on notes subject to change in debt ratings assigned					2.00%
Current Interest rate					9.75%
Premium on repurchase of notes			101% of their principal amount (plus accrued and unpaid interest) in the event of a change in control and a related downgrade of the rating on the notes to below investment grade by both Moody’s Investors Service and Standard & Poor’s Financial Services LLC		101% of their principal amount (plus accrued and unpaid interest) in the event of a change in control and a related downgrade of the rating on the notes to below investment grade by both Moody’s Investors Service and Standard & Poor’s Financial Services LLC		101% of their principal amount (plus accrued and unpaid interest) in the event of a change in control		101% of their principal amount (plus accrued and unpaid interest) in the event of a change in control		105% of their principal amount (plus accrued and unpaid interest) in the event of a change in control or the termination of trading of our common stock on a national securities exchange
Long-term Debt, Maturities, Repayment Terms							we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest.
Maturity date			2016		2018		2018		2014		2018
Cash Interest rate until maturity, redemption or conversion											10.00%
Convertible ratio, shares per $1,000 principal amount of notes											87.7193
Base principal amount of convertible notes											1,000
Initial conversion price per share											$ 11.40
Total shares to be issued on conversion of notes											35,100,000
Current portion of long term debt	7	7											7
Interest rate													2.09%
Liquidity condition under guaranteed obligation of GTL													at least $175 million
Advance payment terms	The 9.75%, 7.75% and 6.3% senior notes contain a provision that allows USG to redeem the notes in whole at any time, or in part from time to time, at our option, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes being redeemed and (2) the sum of the present value of the remaining scheduled payments of principal and interest on the notes being redeemed discounted to the redemption date on a semi-annual basis at the applicable U.S. Treasury rate plus a spread (as outlined in the respective indentures), plus, in each case, any accrued and unpaid interest on the principal amount being redeemed to the redemption date. The 8.375% senior notes contain a similar provision that allows us to redeem those notes, in whole or in part from time to time, at our option, beginning on October 15, 2014 at stated redemption prices, plus any accrued and unpaid interest. In addition, we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest. The 9.75%, 7.75% and 6.3% senior notes contain a provision that allows USG to redeem the notes in whole at any time, or in part from time to time, at our option, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes being redeemed and (2) the sum of the present value of the remaining scheduled payments of principal and interest on the notes being redeemed discounted to the redemption date on a semi-annual basis at the applicable U.S. Treasury rate plus a spread (as outlined in the respective indentures), plus, in each case, any accrued and unpaid interest on the principal amount being redeemed to the redemption date. The 8.375% senior notes contain a similar provision that allows us to redeem those notes, in whole or in part from time to time, at our option, beginning on October 15, 2014 at stated redemption prices, plus any accrued and unpaid interest. In addition, we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest. The 9.75%, 7.75% and 6.3% senior notes contain a provision that allows USG to redeem the notes in whole at any time, or in part from time to time, at our option, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes being redeemed and (2) the sum of the present value of the remaining scheduled payments of principal and interest on the notes being redeemed discounted to the redemption date on a semi-annual basis at the applicable U.S. Treasury rate plus a spread (as outlined in the respective indentures), plus, in each case, any accrued and unpaid interest on the principal amount being redeemed to the redemption date. The 8.375% senior notes contain a similar provision that allows us to redeem those notes, in whole or in part from time to time, at our option, beginning on October 15, 2014 at stated redemption prices, plus any accrued and unpaid interest. In addition, we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest. The 9.75%, 7.75% and 6.3% senior notes contain a provision that allows USG to redeem the notes in whole at any time, or in part from time to time, at our option, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes being redeemed and (2) the sum of the present value of the remaining scheduled payments of principal and interest on the notes being redeemed discounted to the redemption date on a semi-annual basis at the applicable U.S. Treasury rate plus a spread (as outlined in the respective indentures), plus, in each case, any accrued and unpaid interest on the principal amount being redeemed to the redemption date. The 8.375% senior notes contain a similar provision that allows us to redeem those notes, in whole or in part from time to time, at our option, beginning on October 15, 2014 at stated redemption prices, plus any accrued and unpaid interest. In addition, we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest. The 9.75%, 7.75% and 6.3% senior notes contain a provision that allows USG to redeem the notes in whole at any time, or in part from time to time, at our option, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes being redeemed and (2) the sum of the present value of the remaining scheduled payments of principal and interest on the notes being redeemed discounted to the redemption date on a semi-annual basis at the applicable U.S. Treasury rate plus a spread (as outlined in the respective indentures), plus, in each case, any accrued and unpaid interest on the principal amount being redeemed to the redemption date. The 8.375% senior notes contain a similar provision that allows us to redeem those notes, in whole or in part from time to time, at our option, beginning on October 15, 2014 at stated redemption prices, plus any accrued and unpaid interest. In addition, we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest. The 9.75%, 7.75% and 6.3% senior notes contain a provision that allows USG to redeem the notes in whole at any time, or in part from time to time, at our option, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes being redeemed and (2) the sum of the present value of the remaining scheduled payments of principal and interest on the notes being redeemed discounted to the redemption date on a semi-annual basis at the applicable U.S. Treasury rate plus a spread (as outlined in the respective indentures), plus, in each case, any accrued and unpaid interest on the principal amount being redeemed to the redemption date. The 8.375% senior notes contain a similar provision that allows us to redeem those notes, in whole or in part from time to time, at our option, beginning on October 15, 2014 at stated redemption prices, plus any accrued and unpaid interest. In addition, we may redeem the 8.375% senior notes in whole or in part from time to time, at our option, prior to October 15, 2014 at a redemption price equal to 100% of the principal amount of the notes redeemed plus a premium (as specified in the supplemental indenture with respect to those notes), plus any accrued and unpaid interest.												eight years after the date it was advanced, or October 31, 2016 and May 22, 2017 in quarterly installments
Fixed interest rate, Minimum															5.50%
Fixed interest rate, Maximum															6.40%
Weighted average rate of interest															5.87%
Average maturity of industrial revenue bonds															2028 through 2034
Fair value of debt	$ 2,504	$ 2,564