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Asset Retirement Obligations - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended |
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Dec. 31, 2013 Structure | Dec. 31, 2012
Asset Retirement Obligation Disclosure [Abstract] |  |
Estimated CARO ranges per structure, minimum | $ 1 |
Estimated CARO ranges per structure, maximum | 52 |
Number of structures required to demolish | 131 |
Current liability | $ 85 | $ 75

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- Definition Estimated CARO ranges per structure maximum. + References No definition available. + Details
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- Definition Estimated CARO ranges per structure minimum. + References No definition available. + Details
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- Definition Number of structures required to demolish. + References No definition available. + Details
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Balance Type: | na
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- Definition Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
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- Details
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