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Goodwill, Acquisitions Of Controlling Interests

No definition available.

Name:	omc_GoodwillAcquisitionsOfControllingInterests
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Noncontrolling interests' share of goodwill of acquired businesses.

No definition available.

Name:	omc_GoodwillAcquisitionsOfNoncontrollingInterests
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Goodwill, Contingent Purchase Price of Acquired Businesses

No definition available.

Name:	omc_GoodwillContingentPurchasePriceofAcquiredBusinesses
Namespace Prefix:	omc_
Data Type:	xbrli:monetaryItemType
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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Name:	us-gaap_FiniteLivedIntangibleAssetsGross
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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Data Type:	xbrli:monetaryItemType
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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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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.

Name:	us-gaap_GoodwillGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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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.

No definition available.