Leases - Summary of right-of-use assets and lease liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022
Operating lease assets:
Other assets	$ 40.2	$ 42.9
Operating lease liabilities:
Accrued liabilities	9.5	9.9
Other liabilities	40.2	42.7
Total operating lease liabilities	$ 49.7	$ 52.6