8. Investing Activities (Details 7) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Total other-than-temporary debt impairment losses	$ (6.9)		$ (28.8)
Portion of loss recognized in OCI	(0.2)	21.2	11.3	26.1
Net debt impairment losses recognized in earnings	(7.1)		(17.5)
Debt security impairments:
U.S. government and agency
State and political subdivision
Foreign government
Corporate			(0.6)
CMBS	(3.3)		(4.5)
RMBS	(2.6)		(10.4)
CDO/CLO	(0.7)		(0.7)
Other asset-backed	(0.5)		(1.3)
Net debt security impairments	(7.1)		(17.5)
Equity security impairments			(1.5)
Limited partnerships and other investment impairments	(0.3)		(0.3)
Impairment losses	(7.4)		(19.3)
Debt security transaction gains	33.4		41.4
Debt security transaction losses	(1.3)		(4.9)
Equity security transaction gains	5.0		5.0
Equity security transaction losses	(0.2)		(0.3)
Limited partnerships and other investment gains	5.5		6.8
Limited partnerships and other investment losses	(1.5)		(2.5)
Net transaction gains	40.9		45.5
Derivative instruments	(14.2)		(33.4)
Embedded derivatives	7.1		6.9
Fair value investments	1.1		1.9
Net realized investment gains (losses), excluding impairment losses	34.9	(0.4)	20.9	0.5
Net realized investment gains (losses), including impairment losses	27.5		1.6
As restated and amended [Member]
Total other-than-temporary debt impairment losses		(30.9)		(44.6)
Portion of loss recognized in OCI		21.2		26.1
Net debt impairment losses recognized in earnings		(9.7)		(18.5)
Debt security impairments:
U.S. government and agency
State and political subdivision
Foreign government
Corporate		(3.2)		(7.5)
CMBS		(2.5)		(2.5)
RMBS		(2.5)		(7.0)
CDO/CLO		(1.2)		(1.2)
Other asset-backed		(0.3)		(0.3)
Net debt security impairments		(9.7)		(18.5)
Equity security impairments
Limited partnerships and other investment impairments
Impairment losses		(9.7)		(18.5)
Debt security transaction gains		1.8		13.1
Debt security transaction losses		(1.0)		(3.9)
Equity security transaction gains				0.1
Equity security transaction losses		(0.1)		(0.1)
Limited partnerships and other investment gains		0.2		2.6
Limited partnerships and other investment losses		(0.4)		(2.4)
Net transaction gains		0.5		9.4
Derivative instruments		52.3		35.7
Embedded derivatives		(50.5)		(42.9)
Fair value investments		(2.7)		(1.7)
Net realized investment gains (losses), excluding impairment losses		(0.4)		0.5
Net realized investment gains (losses), including impairment losses		$ (10.1)		$ (18.0)