SCHEDULE I SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
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.