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SCHEDULE I SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2012 | Dec. 31, 2011
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Summary of investments other than investments in related parties |  |  |  |
Cost | $ 7,359.3 | [1] |  |
Carrying Value | 7,616.2 | [1] |  |
Fair Value | 7,616.2 | [1] |  |
Investments reclassified to assets held for sale | 338.1 | [2] | 111.8 | [2]
Fixed maturity investments |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 5,454.6 | [1] |  |
Carrying Value | 5,534.3 | [1] |  |
Fair Value | 5,534.3 | [1] |  |
US Government and agency obligations |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 440.4 |  |  |
Carrying Value | 440.1 | [1] |  |
Fair Value | 440.1 |  |  |
Debt securities issued by industrial corporations |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 2,321.4 |  |  |
Carrying Value | 2,385.1 | [1] |  |
Fair Value | 2,385.1 |  |  |
Mortgage-backed and asset-backed securities |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 2,081.0 |  |  |
Carrying Value | 2,095.6 | [1] |  |
Fair Value | 2,095.6 |  |  |
Municipal obligations |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 5.3 |  |  |
Carrying Value | 5.2 | [1] |  |
Fair Value | 5.2 |  |  |
Foreign government, agency and provincial obligations |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 526.6 |  |  |
Carrying Value | 521.9 | [1] |  |
Fair Value | 521.9 |  |  |
Redeemable preferred stocks |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 79.9 |  |  |
Carrying Value | 86.4 | [1] |  |
Fair Value | 86.4 |  |  |
Short-term investments |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 630.6 |  |  |
Carrying Value | 630.6 | [1] |  |
Fair Value | 630.6 |  |  |
Common equity securities |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 895.2 |  |  |
Carrying Value | 1,029.7 | [1] |  |
Fair Value | 1,029.7 |  |  |
Banks, trust and insurance companies |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 268.6 |  |  |
Carrying Value | 324.5 | [1] |  |
Fair Value | 324.5 |  |  |
Public utilities |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 39.1 |  |  |
Carrying Value | 43.6 | [1] |  |
Fair Value | 43.6 |  |  |
Industrial, miscellaneous and other |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 587.5 |  |  |
Carrying Value | 661.6 | [1] |  |
Fair Value | 661.6 |  |  |
Convertible fixed maturity investments |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 121.7 |  |  |
Carrying Value | 127.4 | [1] |  |
Fair Value | 127.4 |  |  |
Other long-term investments |  |  |  |
Summary of investments other than investments in related parties |  |  |  |
Cost | 257.2 |  |  |
Carrying Value | 294.2 | [1] |  |
Fair Value | $ 294.2 |  |  |
[1] | Carrying value and fair value includes $338.1 that is classified as assets held for sale relating to discontinued operations.
[2] | Assets held for sale related to discontinued operations. See Note 20.

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- Definition This element represents the carrying (reported) amount of the entity's investments as of the balance sheet date. This amount may represent the individual investment's or group of similar investments' original cost, fair value, or such other amount at which the investment is shown in the entity's balance sheet. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 15 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 7 -Subparagraph (SX 210.12-15) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611379-123010 + Details
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- Definition This item represents the original cost of the entity's investments including investments in equity securities and, as to fixed maturities, original cost reduced by repayments and adjusted for amortization of premiums or accrual of discounts. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 15 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 7 -Subparagraph (SX 210.12-15) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611379-123010 + Details
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- Definition This item represents the reported amount of the entity's investments measured at fair value. Fair value is the price that would be received to sell an investment in an orderly transaction between market participants at the balance sheet [measurement] date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 15 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 7 -Subparagraph (SX 210.12-15) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611379-123010 + Details
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