Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net Income	$ 406.4	$ 183.6
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Increase in Deferred Policy Acquisition Costs	(66.5)	(82.1)
Amortization of Intangible Assets Acquired	24.3	106.1
Equity in Earnings of Equity Method Limited Liability Investments	0.5	(8.1)
Contribution to Defined Benefit Pension Plan	(55.3)	(5.1)
Distribution of Accumulated Earnings of Equity Method Limited Liability Investments	9.2	9.2
Increase in Value of Equity and Convertible Securities at Fair Value	(99.7)	(12.1)
Amortization of Investment Securities and Depreciation of Investment Real Estate	1.2	6.9
Net Realized Gains on Sales of Investments	(39.1)	(10.0)
Net Impairment Losses Recognized in Earnings	12.1	2.3
Loss from Early Extinguishment of Debt	5.8	0.0
Depreciation and Amortization of Property, Equipment and Software	21.7	12.2
Increase in Receivables	(104.4)	(102.3)
Increase in Insurance Reserves	71.5	131.8
Increase in Unearned Premiums	150.7	102.3
Change in Income Taxes	46.1	4.6
Change in Accrued Expenses and Other Liabilities	(22.8)	(5.4)
Other, Net	4.8	11.4
Net Cash Provided by Operating Activities	366.5	345.3
Investing Activities:
Sales, Paydowns and Maturities of Fixed Maturities	1,067.9	2,133.7
Purchases of Fixed Maturities	(1,013.7)	(1,520.7)
Sales of Equity and Convertible Securities	99.7	186.6
Purchases of Equity and Convertible Securities	(248.2)	(344.3)
Acquisition and Improvements of Investment Real Estate	1.2	1.0
Sale of and Return of Investment of Equity Method Limited Liability Investments	25.7	7.3
Acquisitions of Equity Method Limited Liability Investments	(61.8)	(17.4)
Increase in Short-term Investments	(111.5)	(351.6)
Acquisition of Business, Net of Cash Acquired	0.0	(560.6)
Decrease (Increase) in Other Investments	(32.3)	0.6
Purchases of Corporate-owned Life Insurance	(50.0)	0.0
Acquisition of Software and Long-lived Assets	(53.8)	(53.9)
Other, Net	(2.0)	4.6
Net Cash Used by Investing Activities	(381.2)	(516.7)
Financing Activities:
Net Proceeds from Issuance of Long-term Debt	49.9	249.0
Repayment of Long-term Debt	(185.0)	0.0
Proceeds from Collateralized Investment Borrowings	385.6	10.0
Repayment of Collateralized Investment Borrowings	(258.0)	0.0
Proceeds from Issuance of Common Stock, Net of Transaction Costs	127.5	0.0
Dividends and Dividend Equivalents Paid	(49.1)	(40.7)
Proceeds from Shares Issued under Employee Stock Purchase Plan	1.0	0.0
Cash Exercise of Stock Options	2.2	0.7
Other, Net	(0.9)	(0.5)
Net Cash Provided by Financing Activities	73.2	218.5
Increase in Cash	58.5	47.1
Cash, Beginning of Year	75.1	45.7
Cash, End of Period	$ 133.6	$ 92.8