v3.26.1
Income Taxes - Schedule of 2026 Tax at Statutory Rates (Details) - USD ($)
$ in Millions
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Amount      
Irish Statutory Tax Rate $ 25.8 $ 117.9 $ 135.1
Foreign tax on domestic income 35.3 50.8 60.2
State income taxes, net of federal income tax benefit 2.5 15.2 14.0
Statutory tax rate   17.2 17.7
Share-based payment awards 6.5 2.4 7.6
Nondeductible acquisition costs 10.9    
Unremitted earnings benefit (4.8)    
Other   4.8 2.3
Effect of changes in tax law or rates enacted in the current period (7.9)    
Nontaxable or nondeductible items 4.3 14.2 3.6
Changes in unrecognized tax benefits 19.4    
Total income tax expense $ 102.7 $ 221.4 $ 244.6
Percent      
Irish Statutory Tax Rate 12.50%    
Foreign tax on domestic income 17.10%    
State income taxes, net of federal income tax benefit 1.20%    
Share-based payment awards 3.10%    
Nondeductible acquisition costs 5.30%    
Unremitted earnings benefit (2.30%)    
Effect of changes in tax law or rates enacted in the current period (3.80%)    
Nontaxable or nondeductible items 2.10%    
Changes in unrecognized tax benefits 9.30%    
Effective tax rate 49.70% 34.30% 32.40%
United States      
Amount      
Statutory tax rate $ (16.8)    
Other $ (1.6)    
Percent      
Statutory tax rate (8.10%)    
Other (0.80%)    
Australia      
Amount      
Statutory tax rate $ 17.6    
Other $ 1.0    
Percent      
Statutory tax rate 8.50%    
Other 0.50%    
Germany      
Amount      
Statutory tax rate $ 1.4    
Percent      
Statutory tax rate 0.70%    
Other foreign jurisdictions      
Amount      
Statutory tax rate $ 6.3    
Percent      
Statutory tax rate 3.00%    
Ireland      
Amount      
Other $ 2.8    
Percent      
Other 1.40%