Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net Income	$ 277.4	$ 91.4
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Increase in Deferred Policy Acquisition Costs	(51.1)	(23.5)
Amortization of Intangible Assets Acquired	16.7	1.8
Equity in Earnings of Equity Method Limited Liability Investments	(1.0)	(8.5)
Distribution of Accumulated Earnings of Equity Method Limited Liability Investments	6.3	5.0
Increase in Value of Equity and Convertible Securities at Fair Value	(89.9)	(1.1)
Amortization of Investment Securities and Depreciation of Investment Real Estate	5.9	2.9
Net Realized Gains on Sales of Investments	(37.4)	(6.4)
Net Impairment Losses Recognized in Earnings	10.3	0.5
Depreciation and Amortization of Property, Equipment and Software	14.8	8.2
Increase in Receivables	(95.0)	(38.7)
Increase in Insurance Reserves	56.2	65.8
Increase in Unearned Premiums	121.3	69.9
Change in Income Taxes	23.2	18.8
Change in Accrued Expenses and Other Liabilities	(22.5)	0.3
Other, Net	1.3	5.0
Net Cash Provided by Operating Activities	236.5	191.4
Investing Activities:
Sales, Paydowns and Maturities of Fixed Maturities	959.0	607.5
Purchases of Fixed Maturities	(721.5)	(633.7)
Sales of Equity and Convertible Securities	82.7	122.9
Purchases of Equity and Convertible Securities	(231.7)	(61.9)
Acquisition and Improvements of Investment Real Estate	(0.6)	(0.4)
Sale of and Return of Investment of Equity Method Limited Liability Investments	13.7	6.2
Acquisitions of Equity Method Limited Liability Investments	(51.6)	(12.6)
Decrease (Increase) in Short-term Investments	(353.4)	67.6
Increase (Decrease) in Other Investments	(29.2)	2.1
Purchases of Corporate-owned Life Insurance	(50.0)	0.0
Acquisition of Software and Long-lived Assets	30.7	32.8
Other, Net	(0.3)	3.3
Net Cash Provided (Used) by Investing Activities	(413.6)	68.2
Financing Activities:
Net Proceeds from Issuance of Long-term Debt	0.0	249.4
Repayment of Long-term Debt	(35.0)	0.0
Proceeds from Advances from FHLB	0.0	110.0
Proceeds from Collateralized Investment Borrowings	259.0	10.0
Repayment of Collateralized Investment Borrowings	(113.9)	0.0
Proceeds from Issuance of Common Stock, Net of Transaction Costs	127.5	0.0
Dividends and Dividend Equivalents Paid	(32.8)	(24.9)
Cash Exercise of Stock Options	2.0	0.6
Other, Net	(0.4)	(0.5)
Net Cash Provided by Financing Activities	206.4	344.6
Increase in Cash	29.3	604.2
Cash, Beginning of Year	75.1	45.7
Cash, End of Period	$ 104.4	$ 649.9