Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows From Operating Activities
Net income	$ 168.6	$ 253.9
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on disposal of U.K. motor business	(1.3)	(37.7)
Net loss from repayment of debt	86.1	24.1
Net realized investment gains	(5.1)	(29.6)
Net amortization and depreciation	24.6	22.8
Stock-based compensation expense	8.5	9.4
Amortization of defined benefit plan costs	7.5	10.0
Deferred income tax expense	10.1	40.3
Change in deferred acquisition costs	(27.8)	(21.6)
Change in premiums receivable, net of reinsurance premiums payable	(84.7)	(114.6)
Change in loss, loss adjustment expense and unearned premium reserves	512.5	323.8
Change in reinsurance recoverable	(102.9)	(123.0)
Change in expenses and taxes payable	(31.2)	(5.1)
Other, net	(6.8)	1.7
Net cash provided by operating activities	558.1	354.4
Cash Flows From Investing Activities
Proceeds from disposals and maturities of fixed maturities	1,190.3	1,272.9
Proceeds from disposals of equity securities and other investments	226.1	243.1
Purchase of fixed maturities	(1,443.1)	(1,376.3)
Purchase of equity securities and other investments	(292.2)	(285.8)
Cash received from disposal of U.K. motor business, net of cash transferred		44.3
Capital expenditures	(12.2)	(14.5)
Other investing activities	12.1	4.5
Net cash used in investing activities	(319.0)	(111.8)
Cash Flows From Financing Activities
Proceeds from exercise of employee stock options	14.8	14.3
Proceeds from debt borrowings, net	370.5
Change in cash collateral related to securities lending program	(9.6)	14.1
Dividends paid to shareholders	(59.2)	(54.3)
Repayment of debt	(461.3)	(114.3)
Repurchases of common stock	(105.2)	(85.3)
Other financing activities	(9.8)	(3.7)
Net cash used in financing activities	(259.8)	(229.2)
Effect of exchange rate changes on cash	(2.2)	(1.6)
Net change in cash and cash equivalents	(22.9)	11.8
Cash and cash equivalents, beginning of period	338.8	373.3
Cash and cash equivalents, end of period	$ 315.9	$ 385.1