Goodwill and Other Intangible Assets - goodwill rollforward (Details) $ in Millions	3 Months Ended
Mar. 31, 2017 USD ($)
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 16,617
Foreign exchange translation	74
Other	10
Goodwill, Ending Balance	16,701
Expedia
Goodwill [Line Items]
Goodwill, Beginning Balance	16,560
Foreign exchange translation	74
Other	10
Goodwill, Ending Balance	16,644
Corporate and Other
Goodwill [Line Items]
Goodwill, Beginning Balance	57
Goodwill, Ending Balance	$ 57

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=64834752&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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+ References

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Amount of increase (decrease), classified as other, of an asset representing the future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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