CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows from Operating Activities
Net Income	$ 273.5	$ 229.9
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Change in Receivables	(29.4)	(18.2)
Change in Deferred Acquisition Costs	(17.8)	(20.6)
Change in Insurance Reserves and Liabilities	183.8	128.7
Change in Income Taxes	56.4	92.5
Change in Other Accrued Liabilities	(110.4)	(18.3)
Non-cash Components of Net Investment Income	(95.2)	(103.7)
Net Realized Investment (Gain) Loss	2.2	(11.0)
Depreciation	24.6	26.5
Other, Net	12.2	4.4
Net Cash Provided by Operating Activities	299.9	310.2
Cash Flows from Investing Activities
Proceeds from Sales of Fixed Maturity Securities	84.8	154.3
Proceeds from Maturities of Fixed Maturity Securities	469.8	568.3
Proceeds from Sales and Maturities of Other Investments	82.3	46.5
Purchases of Fixed Maturity Securities	(835.4)	(774.7)
Purchases of Other Investments	(90.0)	(95.7)
Net Sales of Short-term Investments	450.9	10.4
Net Decrease in Payables for Collateral on Investments	(14.0)	(8.4)
Net Purchases of Property and Equipment	(29.1)	(27.3)
Net Cash Provided (Used) by Investing Activities	119.3	(126.6)
Cash Flows from Financing Activities
Long-term Debt Repayments	(15.0)	(15.2)
Issuance of Common Stock	1.3	1.0
Repurchase of Common Stock	(105.7)	(106.9)
Dividends Paid to Stockholders	(52.4)	(46.5)
Other, Net	(15.9)	(9.4)
Net Cash Used by Financing Activities	(187.7)	(177.0)
Net Increase in Cash and Bank Deposits	231.5	6.6
Cash and Bank Deposits at Beginning of Year	77.4	100.4
Cash and Bank Deposits at End of Period	$ 308.9	$ 107.0