Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash Flows From Operating Activities
Net income	$ 137.2	$ 119.6
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on repurchase of debt		11.3
Net realized investment gains	(26.6)	(21.8)
Net amortization and depreciation	16.9	17.4
Stock-based compensation expense	7.3	5.7
Amortization of defined benefit plan costs	5.2	9.2
Deferred income taxes expense	34.9	31.8
Change in deferred acquisition costs	(34.6)	(20.2)
Change in premiums receivable, net of reinsurance premiums payable	(122.8)	(115.7)
Change in loss, loss adjustment expense and unearned premium reserves	352.2	80.8
Change in reinsurance recoverable	(69.9)	45.3
Change in expenses and taxes payable	(101.8)	(111.4)
Other, net	(30.6)	(18.7)
Net cash provided by operating activities	167.4	33.3
Cash Flows From Investing Activities
Proceeds from disposals and maturities of fixed maturities	669.0	869.5
Proceeds from disposals of equity securities and other investments	95.3	85.1
Purchase of fixed maturities	(583.4)	(603.8)
Purchase of equity securities and other investments	(196.4)	(206.9)
Capital expenditures	(7.4)	(10.7)
Net cash (used in) provided by investing activities	(22.9)	133.2
Cash Flows From Financing Activities
Proceeds from exercise of employee stock options	6.7	15.1
Proceeds from debt borrowings, net		169.5
Change in cash collateral related to securities lending program	2.0	(17.7)
Dividends paid to shareholders	(32.6)	(29.3)
Repurchases of debt	(0.1)	(96.8)
Repurchases of common stock	(6.7)	(72.3)
Other financing activities	(2.3)	(3.3)
Net cash used in financing activities	(33.0)	(34.8)
Effect of exchange rate changes on cash	8.5	(6.2)
Net change in cash and cash equivalents	120.0	125.5
Net change in cash related to discontinued operations		0.1
Cash and cash equivalents, beginning of period	486.2	564.8
Cash and cash equivalents, end of period	$ 606.2	$ 690.4