Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2026	Mar. 31, 2025
Deferred tax assets:
Accrued expenses	$ 51.8	$ 51.8
Capital loss carryforward	10.1	9.8
Disallowed expense carryforwards	377.5	242.8
Income tax credits	260.9	266.8
Intangible assets	1,081.1	1,192.1
Inventory valuation	144.5	130.4
Property, plant and equipment	15.4	0.0
Lease liabilities	33.4	33.2
Net operating loss carryforward	62.4	59.3
Share-based compensation	67.0	53.5
Other	20.5	25.6
Gross deferred tax assets	2,124.6	2,065.3
Valuation allowances	(291.6)	(287.4)
Deferred tax assets, net of valuation allowances	1,833.0	1,777.9
Deferred tax liabilities:
Intangible assets	(33.9)	(50.3)
ROU assets	(31.7)	(31.7)
Property, plant and equipment	0.0	(1.6)
Deferred tax liabilities	(65.6)	(83.6)
Net deferred tax asset	1,767.4	1,694.3
Reported as:
Non-current deferred tax assets	1,792.5	1,728.1
Non-current deferred tax liability	(25.1)	(33.8)
Net deferred tax asset	$ 1,767.4	$ 1,694.3

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