Investments - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Net Investment Income
Total net investment income	$ 97.9	$ 95.5
Investment Portfolio
Net Investment Income
Investment expenses	(2.6)	(2.1)
Total net investment income	73.0	71.1
Deposit asset on reinsurance
Net Investment Income
Total net investment income	24.9	24.4
Fixed maturity securities \| Investment Portfolio
Net Investment Income
Net investment income	58.6	58.0
Equity securities \| Investment Portfolio
Net Investment Income
Net investment income	1.3	1.1
Limited partnership interests \| Investment Portfolio
Net Investment Income
Net investment income	13.0	11.3
Short-term and other investments \| Investment Portfolio
Net Investment Income
Net investment income	$ 2.7	$ 2.8

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

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