Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash Flows from Operating Activities:
Net Income	$ 60.6	$ 190.1
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Net Realized Investment (Gains) Losses	(33.1)	(28.2)
Impairment Losses	7.2	19.0
Depreciation and Amortization of Property, Equipment and Software	22.2	16.8
Amortization of Intangibles Assets Acquired	30.6	9.5
(Increase) Decrease in Value of Equity and Convertible Securities	(93.0)	46.2
Receivables from Policyholders	(136.4)	(48.2)
Reinsurance Recoverables	21.2	7.1
Deferred Policy Acquisition Costs	(63.5)	(23.1)
Insurance Reserves	248.8	(96.7)
Unearned Premiums	175.2	97.1
Income Taxes	(67.3)	46.4
Other Assets and Liabilities	81.0	16.9
Net Cash Provided by Operating Activities	237.7	263.8
Cash Flows from Investing Activities:
Proceeds from Sales, Calls and Maturities of Fixed Maturities	726.1	482.5
Proceeds from the Sales or Paydowns of Investments:
Equity Securities	81.6	382.6
Real Estate Investments	2.3	5.4
Mortgage Loans	30.3	13.1
Other Investments	57.9	12.0
Purchases of Investments:
Fixed Maturities	(967.1)	(832.2)
Equity Securities	(38.4)	(309.2)
Real Estate Investments	(1.3)	(0.1)
Corporate-owned Life Insurance	(100.0)	(100.0)
Mortgage Loans	(65.5)	(10.5)
Other Investments	(72.8)	(12.4)
Net Sales (Purchases) of Short-term Investments	605.7	326.7
Payments to Acquire Businesses, Net of Cash Acquired	(316.5)	0.0
Acquisition of Software and Long-lived Assets	(25.5)	(39.4)
Other	5.3	4.7
Net Cash Provided by (Used in) Investing Activities	(77.9)	(76.8)
Cash Flows from Financing Activities:
Repayment of Long-term Debt	(50.0)	0.0
Proceeds from Policyholder Obligations	132.7	322.9
Repayment of Policyholder Obligations	(156.8)	(112.8)
Proceeds from Shares Issued under Employee Stock Purchase Plan	2.5	1.9
Common Stock Repurchases	(151.7)	(110.4)
Dividends and Dividend Equivalents Paid	(41.2)	(39.7)
Other	3.7	3.6
Net Cash (Used in) Provided by Financing Activities	(260.8)	65.5
Increase (Decrease) in Cash	(101.0)	252.5
Cash, Beginning of Year	206.1	136.8
Cash, End of Period	105.1	389.3
Equity Method Limited Liability Investments
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Income (Loss) from Equity Method Investments	38.9	(10.9)
Alternative Energy Partnership Investments
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Income (Loss) from Equity Method Investments	$ (23.1)	$ 0.0