CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities
Net Income	$ 824.2	$ 793.0	$ 1,100.3
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Change in Receivables	678.0	242.9	37.5
Change in Deferred Acquisition Costs	78.0	29.9	(48.7)
Change in Insurance Reserves and Liabilities	74.2	1,481.8	241.1
Change in Income Taxes	295.3	(31.3)	248.2
Change in Other Accrued Liabilities	11.3	160.1	51.3
Non-cash Components of Net Investment Income	(254.7)	(120.5)	(237.9)
Net Investment (Gain) Loss	(76.7)	(1,199.1)	23.2
Depreciation	119.8	113.6	110.1
Cash Related to Reinsurance Transaction	(456.8)	(1,087.2)	0.0
Amortization of the Cost of Reinsurance	79.1	2.6	0.0
Other, Net	15.8	83.5	81.5
Net Cash Provided by Operating Activities	1,387.5	469.3	1,606.6
Cash Flows from Investing Activities
Proceeds from Sales of Fixed Maturity Securities	442.5	990.8	955.2
Proceeds from Maturities of Fixed Maturity Securities	2,611.4	2,052.4	2,401.0
Proceeds from Sales and Maturities of Other Investments	403.1	237.0	363.5
Purchase of Fixed Maturity Securities	(4,106.3)	(3,169.6)	(4,022.4)
Purchase of Other Investments	(606.8)	(440.6)	(568.5)
Net Sales (Purchases) of Short-term Investments	76.5	(133.1)	(267.6)
Net Increase (Decrease) in Payables for Collateral on Investments	(50.7)	314.5	(104.1)
Net Purchases of Property and Equipment	(110.3)	(119.1)	(150.9)
Other, Net	0.0	0.0	(0.3)
Net Cash Used by Investing Activities	(1,340.6)	(267.7)	(1,393.5)
Cash Flows from Financing Activities
Short-term Debt Repayment	0.0	(400.0)	0.0
Issuance of Long-term Debt	588.1	494.1	841.9
Long-term Debt Repayment	(500.0)	(80.0)	(493.1)
Cost Related to Early Retirement of Debt	62.8	0.0	25.9
Issuance of Common Stock	3.4	4.4	6.1
Repurchase of Common Stock	(50.0)	0.0	(400.3)
Dividends Paid to Stockholders	(239.4)	(231.9)	(229.2)
Proceeds from Policyholder Account Deposits	128.1	138.4	149.4
Payments for Policyholder Account Withdrawals	(80.7)	(74.3)	(68.2)
Cash Received Related to Active Life Volatility Cover Agreement	40.4	62.1	0.0
Other, Net	4.0	(1.5)	(3.7)
Net Cash Used by Financing Activities	(168.9)	(88.7)	(223.0)
Net Increase (Decrease) in Cash and Bank Deposits	(122.0)	112.9	(9.9)
Cash and Bank Deposits at Beginning of Year	197.0	84.1	94.0
Cash and Bank Deposits at End of Year	$ 75.0	$ 197.0	$ 84.1