Investment Securities (Details 3) (Level 3 Inputs, USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	$ (34.2)	$ 14.3	$ (38.4)	$ 26.9
Fixed maturity investments
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	(13.5)	3.3	(14.9)	9.5
Common Equity Securities
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	(17.5)	2.5	(17.0)	(20.0)
Other long-term investments.
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	$ (3.2)	$ 8.5	$ (6.5)	$ 37.4