Investments - Summary of Amortized Cost and Fair Values of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Cost	$ 30.8	$ 31.0
Gross unrealized gains	0.1
Gross unrealized losses	(1.8)	(2.2)
Fair value	29.1	28.8
U.S. Treasury securities, obligations of U.S. Government agencies and municipalities
Debt Securities, Available-for-sale [Line Items]
Cost	23.7	22.8
Gross unrealized gains	0.1
Gross unrealized losses	(1.5)	(1.8)
Fair value	22.3	21.0
Corporate debt
Debt Securities, Available-for-sale [Line Items]
Cost	7.1	8.2
Gross unrealized losses	(0.3)	(0.4)
Fair value	$ 6.8	$ 7.8

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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