Borrowing availability that must be maintained under the credit facility as determined by USG's fixed coverage ratio.

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Namespace Prefix:	usg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A textual description providing detail about the type of debt and related terms.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

Maximum borrowing capacity for letters of credit under the line of credit facility.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The expiration date for the U.S. line of credit facility and description of conditions for acceleration of the expiration date.

+ Details

Name:	usg_LineOfCreditFacilityExpirationDateAndDescriptionOfConditionsForAcceleratedExpirationDate
Namespace Prefix:	usg
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the conditions for borrowing under the credit facility including the nature of any restrictions.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
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- Definition

Line Of Credit Facility Maximum Borrowing Capacity after giving effect to increase.

+ Details

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Namespace Prefix:	usg
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum liquidity required to extend maturity of senior notes.

+ Details

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Namespace Prefix:	usg
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 9
-Section 03
-Paragraph 15
-Subparagraph 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15(a))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 7
-Section 03
-Paragraph 15
-Subparagraph a

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the credit facility's borrowing capacity including discussion of how the borrowing capacity is determined (for example, borrowing capacity based on the amount of current assets).

+ References

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Identification of whether the entity has been in compliance with any credit facility debt covenants during the period.

+ References

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects when the credit facility terminates, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

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Namespace Prefix:	us-gaap
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Debt (Details Textual) In Millions, unless otherwise specified			6 Months Ended
	Jun. 30, 2011 USD ($)	Dec. 31, 2010 USD ($)	Jun. 30, 2011 Credit Facility [Member] USD ($)	Jun. 30, 2011 CGC Credit Facility [Member] CAD	Jun. 30, 2011 CGC Credit Facility USD [Member] USD ($)	Jun. 30, 2011 CGC Credit Facility CAD [Member] CAD
Debt (Textuals) [Abstract]
Maximum Borrowing Capacity for letters of credit			$ 250	3
Borrowing capacity description under credit facility			Aggregate principal amount not to exceed the lesser of (a) $400 million or (b) a borrowing base determined by reference to the trade receivables and inventory of USG and its significant domestic subsidiaries
Maximum allowable borrowings after giving effect to the increase			600
Annual facility fees			0.75%
Maturity date of credit facility				June 1, 2012
Line of Credit Facility, Expiration Date and Description of Conditions for Accelerated Expiration Date			The credit facility matures on December 21, 2015 unless terminated earlier in accordance with its terms, including if by May 2, 2014 our 9.75% senior notes due in 2014 are not repaid, their payment is not provided for or their maturity has not been extended until at least 2016 unless we then have liquidity of at least $500 million
Minimum liquidity required to extend maturity of 9.75% senior notes	500
Credit agreement covenant terms			Minimum fixed charge coverage ratio of 1.1-to-1.0 if and for so long as the excess of the borrowing base over the outstanding borrowings under the credit agreement is less than the greater of (a) $40 million and (b) 15% of the lesser of (i) the aggregate revolving commitments at such time and (ii) the borrowing base at such time
Credit agreement current covenant compliance			fixed charge coverage ratio was (0.19)-to-1
Borrowing availability that must be maintained under the credit facility			44
Outstanding letter of credit			80.0			0.4
Borrowing available under credit facility			167		31
Applicable interest rate for credit facility			3.20%		4.30%
Interest rate at a floating rate based on an alternate base rate			Adjusted LIBOR plus 3.00%		Base rate plus 1.50% or the LIBOR rate plus 3.00%, at the option of CGC	Prime rate plus 1.5% or the Bankers’ Acceptance Discount Rate plus 3.00%, at the option of CGC
Interest accured	$ 52	$ 49