v3.26.1
Debt - Debt Obligations (Details) - USD ($)
Jun. 30, 2026
Mar. 31, 2026
Debt Instrument [Line Items]    
Long-term debt $ 5,398,900,000 $ 5,536,900,000
Less: Debt discount (8,400,000) (9,300,000)
Less: Debt issuance costs (29,200,000) (31,200,000)
Net long-term debt including current maturities 5,361,300,000 5,496,400,000
Less: Current maturities 0 0
Net long-term debt 5,361,300,000 5,496,400,000
Senior Indebtedness    
Debt Instrument [Line Items]    
Long-term debt 3,211,000,000 3,349,000,000
Commercial paper    
Debt Instrument [Line Items]    
Long-term debt 211,000,000.0 349,000,000.0
Less: Debt discount $ (400,000) (500,000)
Senior indebtedness | 4.900% 2028 Notes    
Debt Instrument [Line Items]    
Coupon Interest Rate 4.90%  
Effective Interest Rate 5.10%  
Long-term debt $ 1,000,000,000 1,000,000,000
Less: Debt discount (1,900,000) (2,200,000)
Less: Debt issuance costs $ (1,000,000.0) (1,100,000)
Senior indebtedness | 5.050% 2029 Notes    
Debt Instrument [Line Items]    
Coupon Interest Rate 5.05%  
Effective Interest Rate 5.20%  
Long-term debt $ 1,000,000,000 1,000,000,000
Less: Debt discount (3,000,000.0) (3,300,000)
Less: Debt issuance costs $ (1,200,000) (1,200,000)
Senior indebtedness | 5.050% 2030 Notes    
Debt Instrument [Line Items]    
Coupon Interest Rate 5.05%  
Effective Interest Rate 5.20%  
Long-term debt $ 1,000,000,000 1,000,000,000
Less: Debt discount (3,100,000) (3,300,000)
Less: Debt issuance costs (1,300,000) (1,400,000)
Convertible debt    
Debt Instrument [Line Items]    
Long-term debt $ 2,187,900,000 2,187,900,000
Senior subordinated convertible debt | 2017 Senior Convertible Debt    
Debt Instrument [Line Items]    
Coupon Interest Rate 1.625%  
Effective Interest Rate 1.80%  
Long-term debt $ 37,900,000 37,900,000
Senior subordinated convertible debt | 2024 Senior Convertible Debt    
Debt Instrument [Line Items]    
Coupon Interest Rate 0.75%  
Effective Interest Rate 1.00%  
Long-term debt $ 1,250,000,000 1,250,000,000
Less: Debt issuance costs $ (10,700,000) (11,400,000)
Senior subordinated convertible debt | 2026 Senior Convertible Debt    
Debt Instrument [Line Items]    
Coupon Interest Rate 0.00%  
Effective Interest Rate 0.50%  
Long-term debt $ 900,000,000.0 900,000,000.0
Less: Debt issuance costs (15,000,000.0) (16,100,000)
Line of credit | Amended and Restated Credit Agreement | Revolving Credit Facility    
Debt Instrument [Line Items]    
Long-term debt $ 0 $ 0