Income Taxes (Net Deferred Tax Liability) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes Disclosure [Abstract]
Policyholder liabilities	$ 9.6	$ 1.2	$ 1.8
Compensation and benefit plans	49.9	12.6	44.0
Loss carryforwards	46.6	49.7	51.7
Investments	30.4	45.6	35.8
Other	1.3	3.5	2.2
Total deferred tax assets	137.8	112.6	135.5
Less: valuation allowances	(9.5)	(9.5)	(3.1)
Net deferred tax assets	128.3	103.1	132.4
Net unrealized capital gains	116.8	95.7	210.0
Capitalized software	5.6	6.8	8.3
Deferred policy acquisition costs	67.0	63.5	59.7
Intangible assets	0	0.9	2.0
Other	2.0	0.9	0.5
Total deferred tax liabilities	191.4	167.8	280.5
Net deferred tax liability	$ (63.1)	$ (64.7)	$ (148.1)