Sales Inducements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Changes in Deferred Sales Inducement Activity:
Deferred asset, beginning of period	$ 64.3	$ 50.8	$ 60.9	$ 49.7
Sales inducements deferred	2.7	4.8	5.5	9.6
Amortization charged to income	(2.8)	(0.3)	(3.5)	(3.9)
Offsets to net unrealized investment gains or losses included in AOCI	8.4	(8.0)	9.7	(8.1)
Deferred asset, end of period	$ 72.6	$ 47.3	$ 72.6	$ 47.3