Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2024	Mar. 31, 2024
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	$ 6,167.9	$ 5,999.8
Carrying Amount | Term Loan Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	749.5	749.3
Carrying Amount | Commercial Paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	286.9	1,355.1
Carrying Amount | 0.983% 2024 Notes | Senior Indebtedness
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	999.7	999.4
Carrying Amount | 4.250% 2025 Notes | Senior Indebtedness
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,195.9	1,195.0
Carrying Amount | 5.050% 2029 Notes | Senior Indebtedness
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	992.9	992.6
Carrying Amount | 2015 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	6.7	6.7
Carrying Amount | 2017 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	37.9	37.9
Carrying Amount | 2020 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	664.5	663.8
Carrying Amount | 2024 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,233.9	0.0
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	6,298.5	6,106.7
Fair Value | Term Loan Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	750.0	750.0
Fair Value | Commercial Paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	288.0	1,359.0
Fair Value | 0.983% 2024 Notes | Senior Indebtedness
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	991.5	979.6
Fair Value | 4.250% 2025 Notes | Senior Indebtedness
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,181.9	1,181.8
Fair Value | 5.050% 2029 Notes | Senior Indebtedness
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	993.1	1,000.6
Fair Value | 2015 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	25.6	25.6
Fair Value | 2017 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	102.4	101.3
Fair Value | 2020 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	700.7	708.8
Fair Value | 2024 Senior Convertible Debt | Senior Subordinated Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	$ 1,265.3	$ 0.0