Goodwill at Acquisition Date

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- Definition

Percent of Goodwill Allocated to a Business Segment

+ References

No definition available.

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- Definition

Total Acquiree Assets Purchased

+ References

No definition available.

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- Definition

Total Acquiree Liabilities Purchased

+ References

No definition available.

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- Definition

Name of the acquired entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

+ Details

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

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- References

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- Definition

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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Segment Information Segments - Additional Information (Detail) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) Integer	Dec. 31, 2016 USD ($) Rate	Dec. 31, 2015 USD ($) Rate	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 GBP (£) Rate
Segment Reporting [Abstract]
Number of Operating Segments \| Integer	3
Supplementary Insurance Information, by Segment
Percentage Ownership of Acquired Business \| Rate		100.00%	100.00%		100.00%
Name of Acquired Businesses		H&J Capital, L.L.C., parent of Starmount Life Insurance Company and AlwaysCare Benefits (Starmount)	National Dental Plan Limited and associated companies (National Dental)	National Dental Plan Limited and associated companies (National Dental)
Total Cash Purchase Price to Acquire Business		$ 140.3	$ 54.3	£ 35.9
Business Combination, Contingent Consideration, Liability, Noncurrent		10.0
Assets of Acquiree at Acquisition Date		93.1	28.1		£ 18.6
Liabilities of Acquiree at Acquisition Date		55.7	7.5		5.0
Goodwill	$ 338.6	335.1
Payable due 18 Months After Acquisition
Supplementary Insurance Information, by Segment
Business Combination, Contingent Consideration, Liability, Noncurrent		5.0
Payable due 24 Months After Acquisition
Supplementary Insurance Information, by Segment
Business Combination, Contingent Consideration, Liability, Noncurrent		5.0
Unum US and Colonial
Supplementary Insurance Information, by Segment
Goodwill		$ 111.2
Unum US
Supplementary Insurance Information, by Segment
Percent of Goodwill Allocated to a Business Segment \| Rate		75.00%
Goodwill	271.1	$ 271.1
Colonial Life
Supplementary Insurance Information, by Segment
Percent of Goodwill Allocated to a Business Segment \| Rate		25.00%
Goodwill	27.7	$ 27.7
Unum UK
Supplementary Insurance Information, by Segment
Goodwill at Acquisition Date			$ 33.7		£ 22.3
Goodwill	$ 39.8	$ 36.3