Sales Inducements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Changes in Deferred Sales Inducement Activity:
Balance, beginning of period	$ 73.9	$ 64.3	$ 75.7	$ 60.9
Sales inducements deferred	5.4	2.7	7.5	5.5
Amortization charged to income	(1.9)	(2.8)	(2.6)	(3.5)
Offsets to net unrealized investment gains or losses included in AOCI	(2.9)	8.4	(6.1)	9.7
Balance, end of period	$ 74.5	$ 72.6	$ 74.5	$ 72.6