Land-use rights

No definition available.

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- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for advertising of the entity's goods and services. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6911-107765

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 11
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6935-107765

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Value of deferred revenue or cost to provide products or services, which is expected to be recognized in income or incurred within one year or the normal operating cycle, if longer, resulting from customer loyalty program. Excludes liability associated with frequent flier programs. Includes liability associated with customer loyalty programs for other businesses, for example, but is not limited to, hotels, supermarkets, credit card companies, automobile rental companies, and book sellers.

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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-Topic 835
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-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 USD ($)	Mar. 10, 2017 EUR (€)	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 USD ($)	Nov. 25, 2015 EUR (€)	Mar. 03, 2015 EUR (€)	Sep. 23, 2014 EUR (€)
Accounting Policies [Line Items]
Accrued compensation liabilities					$ 288.1			$ 242.6
Accrued online advertising liabilities					284.1			267.5
Customer loyalty program liability, current					104.7			84.4
Land-use rights					$ 50.5			$ 45.3
Software Development [Member]
Accounting Policies [Line Items]
Additions to Capitalized Website Development	$ 80.4	$ 54.2	$ 44.2
0.8% Senior Notes Due March 2022
Accounting Policies [Line Items]
Senior notes face amount \| €				€ 1,000		€ 1,000
2.15% Senior Notes Due November 2022
Accounting Policies [Line Items]
Senior notes face amount \| €				750			€ 750		€ 750
1.8% Senior Notes Due March 2027
Accounting Policies [Line Items]
Senior notes face amount \| €				1,000			1,000			€ 1,000
2.375% Senior Notes Due September 2024
Accounting Policies [Line Items]
Senior notes face amount \| €				€ 1,000			€ 1,000				€ 1,000