Business Segments - Goodwill (Detail) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Goodwill, gross	$ 1,016	$ 948
Accumulated impairment losses	(54)	(54)
Goodwill	962	894
Additions	17
Adjustments	51
North American Full-Service Segment \| Total segment
Segment Reporting Information [Line Items]
Goodwill, gross	409	392
Accumulated impairment losses	0	0
Goodwill	409	392
Additions	17
Adjustments	0
North American Limited-Service Segment \| Total segment
Segment Reporting Information [Line Items]
Goodwill, gross	125	125
Accumulated impairment losses	(54)	(54)
Goodwill	71	71
Additions	0
Adjustments	0
International \| Total segment
Segment Reporting Information [Line Items]
Goodwill, gross	482	431
Accumulated impairment losses	0	0
Goodwill	482	$ 431
Additions	0
Adjustments	$ 51

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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

-Publisher FASB

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

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Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

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