Investments (Narratives) (Details) - USD ($) $ in Millions	6 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2022
Insurance Regulatory Authorites:
Assets held by insurance regulators	$ 22.4		$ 27.1
Available for sale securities:
Fair value of sold available for sale securites	105.5	$ 352.3
Available for sale securities, realized gains	0.8	$ 9.5
Available for sale securities, gross realized losses	$ 1.9

Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

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