CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ (284.7)	$ 252.3	$ 274.3	$ 727.3
Other Comprehensive Income (Loss)
Change in Net Unrealized Gain (Loss) on Securities Before Adjustment (net of tax expense (benefit) of $(80.6); $39.2; $(525.0); $334.7)	(305.0)	66.1	(1,982.1)	616.3
Change in Adjustment to Deferred Acquisition Costs and Reserves for Future Policy and Contract Benefits, Net of Reinsurance (net of tax expense (benefit) of $(69.8); $(31.8); $276.1; $(261.7))	(260.2)	(66.9)	1,051.1	(499.5)
Change in Net Gain on Hedges (net of tax benefit of $4.4; $7.4; $8.3; $19.7)	(16.8)	(13.8)	(32.3)	(36.8)
Change in Foreign Currency Translation Adjustment (net of tax benefit of $-; $-; $0.3; $-)	(15.2)	31.8	(29.5)	88.7
Change in Unrecognized Pension and Postretirement Benefit Costs (net of tax expense of $1.3; $1.5; $4.0; $4.3)	4.9	2.2	14.3	6.6
Total Other Comprehensive Income (Loss)	(592.3)	19.4	(978.5)	175.3
Comprehensive Income (Loss)	$ (877.0)	$ 271.7	$ (704.2)	$ 902.6