Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 283.5	$ 325.4	$ 320.3
Other comprehensive income (loss), before tax:
Unrealized gains/losses on securities	(907.4)	408.7	483.8
Other-than-temporary impairments	2.7	10.6	21.3
Pension and other post-employment benefits liability	(2.2)	(2.2)	7.6
Other comprehensive income (loss), before tax	(906.9)	417.1	512.7
Income tax expense (benefit) related to items of other comprehensive income (loss)	(379.3)	141.6	155.7
Other comprehensive income (loss), after tax	(527.6)	275.5	357.0
Comprehensive income (loss)	$ (244.1)	$ 600.9	$ 677.3