CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash Flows from Operating Activities
Net Income	$ 229.9	$ 210.6
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Change in Receivables	(18.2)	(27.3)
Change in Deferred Acquisition Costs	(20.6)	(20.3)
Change in Insurance Reserves and Liabilities	128.7	113.0
Change in Income Taxes	92.5	83.0
Change in Other Accrued Liabilities	(18.3)	(30.8)
Non-cash Components of Net Investment Income	(103.7)	(86.9)
Net Realized Investment (Gain) Loss	(11.0)	20.5
Depreciation	26.5	25.4
Other, Net	2.2	6.1
Net Cash Provided by Operating Activities	308.0	293.3
Cash Flows from Investing Activities
Proceeds from Sales of Fixed Maturity Securities	154.3	364.8
Proceeds from Maturities of Fixed Maturity Securities	568.3	348.7
Proceeds from Sales and Maturities of Other Investments	48.7	78.5
Purchases of Fixed Maturity Securities	(774.7)	(882.7)
Purchases of Other Investments	(95.7)	(84.0)
Net Sales of Short-term Investments	10.4	70.9
Net Increase (Decrease) in Payables for Collateral on Investments	(8.4)	10.5
Net Purchases of Property and Equipment	(27.3)	(17.2)
Net Cash Used by Investing Activities	(124.4)	(110.5)
Cash Flows from Financing Activities
Long-term Debt Repayments	(15.2)	(13.2)
Issuance of Common Stock	1.0	1.7
Repurchase of Common Stock	(106.9)	(108.8)
Dividends Paid to Stockholders	(46.5)	(45.2)
Other, Net	(9.4)	(9.5)
Net Cash Used by Financing Activities	(177.0)	(175.0)
Net Increase in Cash and Bank Deposits	6.6	7.8
Cash and Bank Deposits at Beginning of Year	100.4	112.9
Cash and Bank Deposits at End of Period	$ 107.0	$ 120.7