DAC and VOBA - Deferred Policy Acquisition Costs (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended						36 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2012 Minimum	Dec. 31, 2012 Maximum
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning balance	$ 334.9		$ 307.6		$ 355.7
Deferrals of commissions and expenses	79.1		79.8		74.7
Amortization:
Amortization	(72.1)		(71.5)		(40.5)
Interest accrued	31.1	[1]	31.9	[1]	29.9	[1]
Net amortization included in the Consolidated Statements of Operations	(41.0)		(39.6)		(10.6)
Change in unrealized capital gains/losses on availabe-for-sale securities	(76.5)		(12.9)		(112.2)
Ending balance	$ 296.5		$ 334.9		$ 307.6
Deferred Policy Acquisition Costs, Interest Accrued Percentage							5.00%	7.00%

[1] Interest accrued at 5.0% to 7.0% during 2012, 2011 and 2010.