Disposals - Additional Information (Detail) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended	1 Months Ended
Sep. 30, 2014 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2013 Conrad Istanbul [member] USD ($)	Dec. 31, 2011 India Joint Venture [member] USD ($)	Dec. 31, 2011 India Joint Venture [member] GBP (£)	Jan. 31, 2011 Beverly Hills Office Building [member] USD ($)
Significant Acquisitions and Disposals [Line Items]
Equity method investment, ownership percentage			25.00%	26.00%	26.00%
Proceeds from sale of equity method investments			$ 17	$ 23	£ 15
Reclassification from accumulated other comprehensive income, before tax			14	8
Gain (loss) on sale of equity investments			(1)	(10)
Proceeds from asset dispositions	40	65				65
Gain (loss) on asset dispositions	$ 13					$ 16

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=6516133

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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