Business Segments - Schedule of Goodwill (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Goodwill, gross		$ 8,636	$ 7,652
Accumulated impairment losses		(54)	(54)
Goodwill	$ 7,598	8,582	7,598
Goodwill [Roll Forward]
Goodwill	7,598
Adjustments	870
Foreign currency translation	114
Goodwill	8,582
North American Full-Service
Segment Reporting Information [Line Items]
Goodwill, gross		3,283	2,905
Accumulated impairment losses		0	0
Goodwill	2,905	3,283	2,905
Goodwill [Roll Forward]
Goodwill	2,905
Adjustments	370
Foreign currency translation	8
Goodwill	3,283
North American Limited-Service
Segment Reporting Information [Line Items]
Goodwill, gross		1,723	1,558
Accumulated impairment losses		(54)	(54)
Goodwill	1,504	1,669	1,504
Goodwill [Roll Forward]
Goodwill	1,504
Adjustments	162
Foreign currency translation	3
Goodwill	1,669
Asia Pacific
Segment Reporting Information [Line Items]
Goodwill, gross		1,825	1,572
Accumulated impairment losses		0	0
Goodwill	1,572	1,825	1,572
Goodwill [Roll Forward]
Goodwill	1,572
Adjustments	213
Foreign currency translation	40
Goodwill	1,825
Other International
Segment Reporting Information [Line Items]
Goodwill, gross		1,805	1,617
Accumulated impairment losses		0	0
Goodwill	1,617	$ 1,805	$ 1,617
Goodwill [Roll Forward]
Goodwill	1,617
Adjustments	125
Foreign currency translation	63
Goodwill	$ 1,805

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
-Subparagraph (a)
-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
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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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.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the 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
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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