Estimated Fair Value of Assets Acquired and Liabilities Assumed in Acquisitions (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014
Business Combinations [Abstract]
Property and equipment	$ 131
Other assets	3
Total assets	134
Other liabilities	(1)
Net assets acquired	$ 133

Amount of assets acquired at the acquisition date.

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- Definition

Amount of other assets expected to be realized or consumed before one year or the normal operating cycle, if longer, acquired at the acquisition date.

+ References

+ Details

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- Definition

Amount of liabilities assumed at the acquisition date.

+ References

+ Details

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- Definition

Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 55

-Paragraph 37

-URI http://asc.fasb.org/extlink&oid=35744172&loc=d3e2207-128464

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- Definition

The amount of property, plant, and equipment recognized as of the acquisition date.

+ References

+ Details

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- Details

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