Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash Flows From Operating Activities
Net income	$ 167.0	$ 123.6
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized and unrealized investment losses (gains)	19.4	(7.8)
Net amortization and depreciation	14.1	15.4
Stock-based compensation expense	7.6	7.3
Amortization of defined benefit plan costs	4.8	7.0
Deferred income tax (benefit) expense	(4.0)	7.6
Change in deferred acquisition costs	(14.3)	(29.6)
Change in premiums receivable, net of reinsurance premiums payable	(100.6)	(73.8)
Change in loss, loss adjustment expense and unearned premium reserves	249.3	384.7
Change in reinsurance recoverable	(53.3)	(72.7)
Change in expenses and taxes payable	(62.4)	(74.1)
Other, net	(48.1)	(37.8)
Net cash provided by operating activities	179.5	249.8
Cash Flows From Investing Activities
Proceeds from disposals and maturities of fixed maturities	637.8	578.8
Proceeds from disposals of equity securities and other investments	51.2	65.8
Purchase of fixed maturities	(822.6)	(668.4)
Purchase of equity securities and other investments	(92.8)	(113.5)
Capital expenditures	(7.8)	(8.6)
Net cash used in investing activities	(234.2)	(145.9)
Cash Flows From Financing Activities
Proceeds from exercise of employee stock options	11.1	10.3
Change in cash collateral related to securities lending program	(12.7)	(3.4)
Dividends paid to shareholders	(45.9)	(42.6)
Repurchases of common stock	(25.3)	(28.0)
Other financing activities	(3.2)	(2.8)
Net cash used in financing activities	(76.0)	(66.5)
Effect of exchange rate changes on cash	(0.8)	1.6
Net change in cash and cash equivalents	(131.5)	39.0
Net change in cash related to discontinued operations		(3.8)
Cash and cash equivalents, beginning of period	376.4	282.6
Cash and cash equivalents, end of period	$ 244.9	$ 317.8