XML 74 R72.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Timing of Anticipated Settlements of Interest Rate Swaps Outstanding (Detail) (USD $) In Millions, unless otherwise specified | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009 | Dec. 31, 2008
--- | --- | --- | --- | ---
Derivative [Line Items] |  |  |  |
Notional Value | $ 1,413.0 | $ 1,681.9 | $ 1,620.7 | $ 2,532.1
2012 |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Value | 185.0 |  |  |
Weighted Average Receive Rate | 6.49% |  |  |
Weighted Average pay rate | 0.58% |  |  |
2013 |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Value | 150.0 |  |  |
Weighted Average Receive Rate | 6.34% |  |  |
Weighted Average pay rate | 0.58% |  |  |
Receive Fixed/Pay Variable |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Value | $ 335.0 |  |  |
Weighted Average Receive Rate | 6.42% |  |  |
Weighted Average pay rate | 0.58% |  |  |

X
- Definition Derivative, Weighted Average Pay Rate + References No definition available. + Details
Name: | unm_DerivativeWeightedAveragePayRate
Namespace Prefix: | unm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Derivative, Weighted Average Receive Rate + References No definition available. + Details
Name: | unm_DerivativeWeightedAverageReceiveRate
Namespace Prefix: | unm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate notional amount of all derivatives. The notional amount relates to a number of currency units, shares, bushels, pounds, or other units specified in a derivative instrument. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Notional Amount -URI http://asc.fasb.org/extlink&oid=6519104 + Details
Name: | us-gaap_NotionalAmountOfDerivatives
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant