Weighted-average Assumptions Used to Determine Domestic Benefit Obligations (Detail)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Pension
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.05%	5.90%	6.00%
Rate of compensation increase	4.00%	4.00%	4.00%
Post-retirement
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.05%	5.90%	6.00%

Expected rate of compensation increases (for pay-related plans).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph j

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(2)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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