CONSOLIDATED STATEMENTS OF INCOME (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue
Premium Income	$ 7,716.1	$ 7,514.2	$ 7,431.4
Net Investment Income	2,515.2	2,519.6	2,495.5
Realized Investment Gain (Loss)
Total Other-Than-Temporary Impairment Loss on Fixed Maturity Securities	0	(19.9)	(15.9)
Other Net Realized Investment Gain	56.2	15.0	40.6
Net Realized Investment Gain (Loss)	56.2	(4.9)	24.7
Other Income	227.9	249.1	241.6
Total Revenue	10,515.4	10,278.0	10,193.2
Benefits and Expenses
Benefits and Change in Reserves for Future Benefits	6,722.2	7,209.5	6,354.1
Commissions	917.2	879.2	855.4
Interest and Debt Expense	145.4	143.3	141.8
Deferral of Acquisition Costs	(467.3)	(442.5)	(422.5)
Amortization of Deferred Acquisition Costs	378.7	365.7	373.3
Impairment of Deferred Acquisition Costs	0	196.0	0
Compensation Expense	786.8	808.0	776.3
Other Expenses	782.9	785.5	794.9
Total Benefits and Expenses	9,265.9	9,944.7	8,873.3
Income Before Income Tax	1,249.5	333.3	1,319.9
Income Tax (Benefit)
Current	206.6	230.5	301.0
Deferred	148.5	(181.4)	140.2
Total Income Tax	355.1	49.1	441.2
Net Income	$ 894.4	$ 284.2	$ 878.7
Net Income Per Common Share
Basic	$ 3.18	$ 0.94	$ 2.70
Diluted	$ 3.17	$ 0.94	$ 2.69