CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows from Operating Activities
Net Income	$ 894.4	$ 284.2	$ 878.7
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Change in Receivables	40.4	37.0	1.7
Change in Deferred Acquisition Costs	(88.6)	(76.8)	(49.2)
Impairment of Deferred Acquisition Costs	0	196.0	0
Change in Insurance Reserves and Liabilities	508.4	1,113.9	537.8
Change in Income Taxes	168.0	(274.4)	160.3
Change in Other Accrued Liabilities	18.6	68.4	(95.5)
Non-cash Adjustments to Net Investment Income	(221.3)	(240.6)	(276.2)
Net Realized Investment (Gain) Loss	(56.2)	4.9	(24.7)
Depreciation	84.3	81.1	75.4
Other, Net	31.6	0	(11.5)
Net Cash Provided by Operating Activities	1,379.6	1,193.7	1,196.8
Cash Flows from Investing Activities
Proceeds from Sales of Fixed Maturity Securities	595.9	1,181.9	1,122.8
Proceeds from Maturities of Fixed Maturity Securities	2,160.5	1,692.7	2,192.8
Proceeds from Sales and Maturities of Other Investments	182.2	131.9	140.3
Purchase of Fixed Maturity Securities	(3,512.8)	(2,760.1)	(3,798.6)
Purchase of Other Investments	(353.8)	(304.1)	(332.8)
Net Purchases of Short-term Investments	(80.1)	(254.6)	(288.1)
Other, Net	(105.3)	(98.0)	(110.1)
Net Cash Used by Investing Activities	(1,113.4)	(410.3)	(1,073.7)
Cash Flows from Financing Activities
Net Short-term Debt Borrowings	143.5	87.2	0
Issuance of Long-term Debt	246.4	0	396.9
Long-term Debt Repayments	(70.0)	(84.4)	(78.3)
Issuance of Common Stock	4.9	14.8	10.0
Repurchase of Common Stock	(496.7)	(619.9)	(356.0)
Dividends Paid to Stockholders	(133.8)	(121.0)	(114.8)
Other, Net	0.2	2.9	1.1
Net Cash Used by Financing Activities	(305.5)	(720.4)	(141.1)
Net Increase (Decrease) in Cash and Bank Deposits	(39.3)	63.0	(18.0)
Cash and Bank Deposits at Beginning of Year	116.6	53.6	71.6
Cash and Bank Deposits at End of Year	$ 77.3	$ 116.6	$ 53.6