CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Change in Net Unrealized Gain on Securities Not Other-Than-Temporarily Impaired, tax expense	$ 303.1	$ 599.6	$ 496.5	$ 754.9
Change in Net Unrealized Gain on Securities Other-Than-Temporarily Impaired, tax benefit	0	0	0	1.1
Total Change in Net Unrealized Gain on Securities Before Reclassification Adjustment, tax expense	303.1	599.6	496.5	753.8
Reclassification Adjustment for Net Realized Investment Gain, tax expense	1.4	3.4	2.0	4.6
Change in Net Gain on Cash Flow Hedges, tax expense (benefit)	(6.0)	34.7	(5.3)	32.0
Change in Adjustment to Reserves for Future Policy and Contract Benefits Net of Reinsurance and Other, tax benefit	213.5	377.6	344.0	498.8
Change in Unrecognized Pension and Postretirement Benefit Costs, tax expense	$ 3.5	$ 2.8	$ 11.0	$ 6.9