Additional Financial Information - Schedule of Composition of Other Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Mar. 31, 2024
Other current assets
Prepaid expenses and other	$ 38.0	$ 34.8
Restricted cash	42.8	43.7
Contract assets	72.5	59.9
Interest rate swap assets	0.0	35.6
Tax credits receivable	140.7	199.1
Other current assets	294.0	373.1
Other non-current assets
Prepaid expenses and other	16.9	18.3
Restricted cash	10.8	13.7
Accounts receivable	48.0	111.7
Contract assets	10.3	3.2
Tax credits receivable	440.6	361.7
Operating lease right-of-use assets	300.1	344.3
Interest rate swap assets	0.7	0.0
Other non-current assets	$ 827.4	$ 852.9