Investment Securities (Details 4) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Investment securities
Cost or amortized cost	$ 5,275.6	$ 5,755.9
Gross unrealized gains	129.6	133.6
Gross unrealized losses	(28.2)	(44.2)
Net foreign currency gains (losses)	13.6	(59.2)
Fixed maturity investments, at fair value	5,287.7	5,786.1
Fixed maturity investments, at fair value	5,390.6
Carrying value, common equity securities	669.8	667.0
Carrying value, other long-term investments	328.8	372.1
Carrying value, convertible fixed securities	140.5	143.0
AutoOne investments that are reclassified to assets held for sale	102.9
U.S. Government and agency obligations
Investment securities
Cost or amortized cost	347.1	385.9
Gross unrealized gains	5.8	13.6
Gross unrealized losses	(0.2)	(0.8)
Net foreign currency gains (losses)	0.4
Fixed maturity investments, at fair value	353.1	398.7
Debt securities issued by corporations
Investment securities
Cost or amortized cost	1,990.0	2,149.2
Gross unrealized gains	76.6	87.9
Gross unrealized losses	(11.9)	(21.1)
Net foreign currency gains (losses)	(0.8)	(37.9)
Fixed maturity investments, at fair value	2,053.9	2,178.1
Municipal obligations
Investment securities
Cost or amortized cost	2.4	3.3
Gross unrealized gains		0.1
Gross unrealized losses		(0.1)
Fixed maturity investments, at fair value	2.4	3.3
Mortgage-backed and asset-backed securities
Investment securities
Cost or amortized cost	2,200.8	2,082.0
Gross unrealized gains	29.8	18.2
Gross unrealized losses	(4.9)	(15.6)
Net foreign currency gains (losses)	14.9	(12.9)
Fixed maturity investments, at fair value	2,240.6	2,071.7
Foreign government, agency and provincial obligations
Investment securities
Cost or amortized cost	653.0	1,053.6
Gross unrealized gains	14.1	7.7
Gross unrealized losses	(0.2)	(6.6)
Net foreign currency gains (losses)	(0.9)	(8.3)
Fixed maturity investments, at fair value	666.0	1,046.4
Non-cumulative perpetual preference shares
Investment securities
Cost or amortized cost	82.3	81.9
Gross unrealized gains	3.3	6.1
Gross unrealized losses	(11.0)
Net foreign currency gains (losses)		(0.1)
Fixed maturity investments, at fair value	74.6	87.9
Equity security investments
Investment securities
Cost or amortized cost	661.0	561.2
Gross unrealized gains	35.4	105.5
Gross unrealized losses	(26.6)	(1.5)
Net foreign currency gains (losses)		1.8
Carrying value, common equity securities	669.8	667.0
Convertible fixed maturity investments
Investment securities
Cost or amortized cost	143.7	126.9
Gross unrealized gains	4.4	16.2
Gross unrealized losses	(7.6)	(0.1)
Carrying value, convertible fixed securities	140.5	143.0
Other long-term investments
Investment securities
Cost or amortized cost	290.2	329.5
Gross unrealized gains	56.2	62.4
Gross unrealized losses	(15.2)	(13.0)
Net foreign currency gains (losses)	(2.4)	(6.8)
Carrying value, other long-term investments	$ 328.8	$ 372.1

Other long-term investments not otherwise specified in the taxonomy, not including investments in marketable securities.

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