Statutory Financial Information - Additional Details (Detail) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013 UnumProvidentInternationalLimited [Domain] USD ($)	Dec. 31, 2013 UnumLimited [Domain] GBP (£)	Dec. 31, 2013 United States Traditional Insurance Subsidiaries [Member] USD ($)	Dec. 31, 2012 United States Traditional Insurance Subsidiaries [Member] USD ($)	Dec. 31, 2011 United States Traditional Insurance Subsidiaries [Member] USD ($)
Statutory Accounting Practices [Line Items]
CapitalandSurplusIncreaseFromRedomestication	$ 176
Statutory Net Income		94.6	584.5	624.5	642.9
Statutory Combined Capital and Surplus		438.1	3,450.5	3,426.5
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments		187.8	591.0
Cash and Securities Segregated under Federal and Other Regulations			$ 280.5	$ 277.5

CapitalandSurplusIncreaseFromRedomestication

No definition available.

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- Definition

Amount of cash subject to withdrawal restrictions, restricted deposits held as compensating balances, and cash and securities segregated in compliance with regulations (such as cash deposited in a special reserve account for the exclusive benefit of customers).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 305

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6478312&loc=d3e61473-112792

+ Details

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- Definition

Amount of dividends available for payment after computation of statutory restrictions on capital surplus.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(e))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph e

-Article 4

+ Details

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- Definition

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.23(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 24

-Subparagraph c

-Article 7

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- Definition

Amount of net income for the period determined using accounting principles prescribed or permitted by insurance regulators.

+ References

+ Details

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