Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities:
Net Income	$ 91.4	$ 36.3
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Amortization of Intangible Assets Acquired	1.8	2.6
Equity in Earnings of Equity Method Limited Liability Investments	(8.5)	(10.8)
Distribution of Accumulated Earnings of Equity Method Limited Liability Investments	5.0	11.1
Decrease (Increase) in Value of Fair Value Option Investments Reported in Investment Income	0.0	(0.5)
Decrease (Increase) in Value of Equity Securities at Fair Value	(1.1)	0.0
Amortization of Investment Securities and Depreciation of Investment Real Estate	2.9	8.7
Net Realized Gains on Sales of Investments	(6.4)	(36.9)
Net Impairment Losses Recognized in Earnings	0.5	7.6
Depreciation of Property and Equipment	8.2	6.2
Increase in Receivables	(38.7)	(9.2)
Increase in Deferred Policy Acquisition Costs	(23.5)	(16.5)
Increase in Insurance Reserves	65.8	59.8
Increase in Unearned Premiums	69.9	31.8
Change in Income Taxes	18.8	9.4
Change in Accrued Expenses and Other Liabilities	0.3	6.5
Other, Net	5.0	(2.1)
Net Cash Provided by Operating Activities	191.4	104.0
Investing Activities:
Sales, Paydowns and Maturities of Fixed Maturities	607.5	205.4
Purchases of Fixed Maturities	(633.7)	(264.4)
Sales of Equity Securities	122.9	191.1
Purchases of Equity Securities	(61.9)	(197.4)
Return of Investment of Equity Method Limited Liability Investments	6.2	32.2
Acquisitions of Equity Method Limited Liability Investments	(12.6)	(9.3)
Sales of Fair Value Option Investments	0.0	34.9
Decrease (Increase) in Short-term Investments	67.6	144.2
Improvements of Investment Real Estate	(0.4)	(1.0)
Sales of Investment Real Estate	0.0	14.7
Increase (Decrease) in Other Investments	2.1	(0.9)
Acquisition and Development of Software	(32.8)	(21.3)
Other, Net	3.3	(3.6)
Net Cash Provided by Investing Activities	68.2	124.6
Financing Activities:
Net Proceeds from Issuance of Long-term Debt	249.4	200.2
Repayment of Long-term Debt	0.0	(360.0)
Dividends and Dividend Equivalents Paid	(24.9)	(24.7)
Proceeds from Short-term Debt, Maturing in More than Three Months	120.0
Cash Exercise of Stock Options	0.6	0.9
Other, Net	(0.5)	0.2
Net Cash Provided (Used) by Financing Activities	344.6	(183.4)
Increase in Cash	604.2	45.2
Cash, Beginning of Year	45.7	115.7
Cash, End of Period	$ 649.9	$ 160.9