8. Separate Accounts Death Benefits and Other Insurance Benefit Features and Embedded Product Derivatives (Details 2) (USD $) In Millions, unless otherwise specified			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011 As restated and amended [Member]	Sep. 30, 2012 Return of premium	Dec. 31, 2011 Return of premium As restated and amended [Member]	Sep. 30, 2012 Step up	Dec. 31, 2011 Step up As restated and amended [Member]	Sep. 30, 2012 Earnings enhancement benefit ("EEB")	Dec. 31, 2011 Earnings enhancement benefit ("EEB") As restated and amended [Member]	Sep. 30, 2012 Greater of annual step up and roll up	Dec. 31, 2011 Greater of annual step up and roll up As restated and amended [Member]
Account Value	$ 2,286.9	$ 2,313.0	$ 776.0	$ 795.6	$ 1,444.5	$ 1,450.6	$ 38.9	$ 39.7	$ 27.5	$ 27.1
Net Amount at Risk After Reinsurance	40.7	121.1	7.1	20.7	26.0	91.2	0.1	0.4	7.5	8.8
Average Attained Age Of Annuitant			62 years	61 years	62 years	62 years	63 years	62 years	66 years	66 years
Less: General account value with GMDB	318.2	336.9
Subtotal separate account liabilities with GMDB	1,968.7	1,976.1
Separate account liabilities without GMDB	142.0	570.7
Total separate account liabilities	2,110.7	2,546.8
GMIB(1) ending balance	$ 413.4	$ 428.1