Investment Securities (Details 3) (Level 3 Inputs, USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	$ (4.2)	$ (30.0)	$ (11.8)	$ 12.6
Fixed maturity investments
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	(3.3)	(3.4)	(1.4)	6.2
Common Equity Securities
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	1.3	(19.1)	(0.5)	(22.5)
Other long-term investments.
Investment securities
Total pre-tax gains (losses) included in earnings attributable to unrealized investment gains (losses) for Level 3 investments	$ (2.2)	$ (7.5)	$ (9.9)	$ 28.9