Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash Flows from Operating Activities:
Net Income (Loss)	$ (94.8)	$ 123.2
Adjustments to Reconcile Net Income (Loss) to Net Cash Provided by (Used in) Operating Activities:
Net Realized Investment (Gains) Losses	(1.5)	(13.8)
Impairment Losses	8.9	4.0
Depreciation and Amortization of Property, Equipment and Software	13.4	11.1
Amortization of Intangibles Acquired	6.2	3.2
Loss from Early Extinguishment of Debt	3.7	0.0
Change in Accumulated Undistributed Earnings of Equity Method Limited Liability Investments	(5.8)	(18.1)
(Increase) Decrease in Value of Equity and Convertible Securities	28.2	(52.2)
Receivables from Policyholders	14.2	(66.7)
Reinsurance Recoverables	(0.3)	5.0
Deferred Policy Acquisition Costs	(2.4)	(21.3)
Insurance Reserves	2.9	29.8
Unearned Premiums	(8.2)	97.9
Income Taxes	(30.5)	(37.3)
Other Assets and Liabilities	31.1	60.4
Net Cash Provided by (Used in) Operating Activities	(18.2)	140.6
Cash Flows from Investing Activities:
Proceeds from Sales, Calls and Maturities of Fixed Maturities	128.6	291.2
Proceeds from the Sales or Paydowns of Investments:
Other Investments	249.7	27.3
Mortgage Loans	22.8	12.8
Other Investments	20.5	7.0
Purchases of Investments:
Fixed Maturities	(527.2)	(503.2)
Equity Securities	(21.3)	(12.5)
Real Estate Investments	0.0	(0.2)
Company-Owned Life Insurance	(100.0)	(100.0)
Mortgage Loans	(21.3)	(33.7)
Other Investments	1.9	50.1
Net Sales (Purchases) of Short-term Investments	40.3	677.4
Acquisition of Software and Long-lived Assets	(16.0)	(9.2)
Other	0.7	4.9
Net Cash Provided by (Used in) Investing Activities	(225.1)	311.7
Cash Flows from Financing Activities:
Repayment of Long-term Debt	(280.0)	(50.0)
Proceeds from Issuance of Senior Long-term Debt	396.3	0.0
Proceeds from Issuance of Subordinated Long-term Debt	145.6	0.0
Proceeds from Policyholder Obligations	208.6	60.7
Repayment of Policyholder Obligations	(57.8)	(61.5)
Proceeds from Shares Issued under Employee Stock Purchase Plan	1.3	1.2
Common Stock Repurchases	0.0	(42.1)
Dividends and Dividend Equivalents Paid	(19.8)	(21.0)
Other	0.3	1.7
Net Cash Provided by (Used in) Financing Activities	392.4	(111.0)
Increase (Decrease) in Cash	149.1	341.3
Cash, Beginning of Year	148.2	206.1
Cash, End of Period	297.3	547.4
Senior Notes, 3.800 Percent Due February 23, 2033
Cash Flows from Financing Activities:
Payments of Debt Issuance Costs	(1.2)
5.875% Fixed-Rate Reset Junior Subordinated Debentures due 2062
Cash Flows from Financing Activities:
Payments of Debt Issuance Costs	(0.9)
Alternative Energy Partnership Investments
Adjustments to Reconcile Net Income (Loss) to Net Cash Provided by (Used in) Operating Activities:
Income (Loss) from Equity Method Investments	$ (16.7)	$ (15.4)