CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net Income	$ 867.1	$ 402.1	$ 847.0
Other Comprehensive Income (Loss)
Change in Net Unrealized Gain on Securities Before Adjustment (net of tax expense (benefit) of $(892.5); $725.8; $(1,102.8))	(1,720.9)	1,439.3	(2,101.2)
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance (net of tax expense (benefit) of $856.6; $(665.1); $743.3)	1,634.9	(1,284.7)	1,363.4
Change in Net Gain on Cash Flow Hedges (net of tax benefit of $4.3; $2.0; $1.3)	(13.0)	(5.3)	(5.3)
Change in Foreign Currency Translation Adjustment (net of tax benefit of $0.1; $-; $-)	(60.2)	(66.3)	25.5
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense (benefit) of $3.2; $(92.4); $185.2)	8.9	(171.6)	344.6
Total Other Comprehensive Loss	(150.3)	(88.6)	(373.0)
Comprehensive Income	$ 716.8	$ 313.5	$ 474.0