Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2022	Mar. 31, 2022
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	$ 7,303.5	$ 7,687.4
Carrying Amount | Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	962.7	1,388.5
Carrying Amount | 4.333% 2023 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	997.6	995.8
Carrying Amount | 2.670% 2023 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	998.6	997.9
Carrying Amount | 0.972% 2024 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,397.3	1,396.2
Carrying Amount | 0.983% 2024 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	997.1	996.4
Carrying Amount | 4.250% 2025 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,190.1	1,188.5
Carrying Amount | 2015 Senior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	12.3	30.6
Carrying Amount | 2017 Senior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	81.7	104.1
Carrying Amount | 2020 Senior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	659.7	584.0
Carrying Amount | 2017 Junior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	6.4	5.4
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	7,207.8	8,105.9
Fair Value | Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	972.1	1,399.1
Fair Value | 4.333% 2023 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	998.0	1,017.1
Fair Value | 2.670% 2023 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	982.1	997.7
Fair Value | 0.972% 2024 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,319.9	1,343.9
Fair Value | 0.983% 2024 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	921.2	946.3
Fair Value | 4.250% 2025 Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	1,152.0	1,213.6
Fair Value | 2015 Senior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	34.7	115.4
Fair Value | 2017 Senior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	142.8	285.6
Fair Value | 2020 Senior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	672.2	765.5
Fair Value | 2017 Junior Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for debt obligations	$ 12.8	$ 21.7