v3.26.1
Income Taxes (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Income Tax Disclosure [Abstract]        
Unrecognized tax benefits $ 718.7   $ 718.7  
Unrecognized tax benefits, net of federal benefit 655.7   655.7  
Tax benefits that would reduce income tax expense and effective tax rate 618.7   618.7  
Unrecognized tax benefits - interest and penalties $ 81.2   81.2  
Unrecognized tax benefits increase     $ 78.2  
Effective tax rate (as a percent) 22.10% 23.00% 21.60% 22.30%