v3.26.1
Debt - Schedule of Debt Instruments (Details)
Jun. 30, 2026
USD ($)
Jun. 30, 2026
EUR (€)
Feb. 28, 2026
USD ($)
Sep. 30, 2025
USD ($)
Debt Instrument [Line Items]        
Long-term debt $ 11,723,241,000     $ 7,660,773,000
Long-term debt 11,444,086,000     7,542,988,000
Multi-currency revolving credit facility due in 2030        
Debt Instrument [Line Items]        
Long-term debt 17,611,000     0
Less current portion 17,611,000     0
Receivables securitization facility due in 2028        
Debt Instrument [Line Items]        
Long-term debt 0     0
Term loan due in 2027        
Debt Instrument [Line Items]        
Long-term debt 399,423,000     799,043,000
Term loan due in 2029        
Debt Instrument [Line Items]        
Long-term debt 999,156,000     0
Money market facility due in 2027        
Debt Instrument [Line Items]        
Long-term debt 0     0
Working capital credit facility due in 2027        
Debt Instrument [Line Items]        
Long-term debt 0     0
$750,000, 3.450% senior notes due 2027        
Debt Instrument [Line Items]        
Principal amount $ 750,000,000      
Interest rate (as a percent) 3.45% 3.45%    
Long-term debt $ 748,781,000     748,150,000
$500,000, 4.625% senior notes due 2027        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000      
Interest rate (as a percent) 4.625% 4.625%    
Long-term debt $ 498,227,000     497,309,000
€500,000, 2.875% senior notes due 2028        
Debt Instrument [Line Items]        
Principal amount | €   € 500,000    
Interest rate (as a percent) 2.875% 2.875%    
Long-term debt $ 567,484,000     583,903,000
$500,000, 3.950% senior notes due 2029        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000   $ 500,000,000  
Interest rate (as a percent) 3.95% 3.95% 3.95%  
Long-term debt $ 497,247,000     0
$600,000, 4.850% senior notes due 2029        
Debt Instrument [Line Items]        
Principal amount $ 600,000,000      
Interest rate (as a percent) 4.85% 4.85%    
Long-term debt $ 597,208,000     596,603,000
$500,000, 2.800% senior notes due 2030        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000      
Interest rate (as a percent) 2.80% 2.80%    
Long-term debt $ 497,633,000     497,174,000
$500,000, 4.250% senior notes due 2030        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000   $ 500,000,000  
Interest rate (as a percent) 4.25% 4.25% 4.25%  
Long-term debt $ 496,319,000     0
$1,000,000, 2.700% senior notes due 2031        
Debt Instrument [Line Items]        
Principal amount $ 1,000,000,000      
Interest rate (as a percent) 2.70% 2.70%    
Long-term debt $ 994,678,000     993,838,000
€500,000, 3.625% senior notes due 2032        
Debt Instrument [Line Items]        
Principal amount | €   € 500,000    
Interest rate (as a percent) 3.625% 3.625%    
Long-term debt $ 565,036,000     581,685,000
$500,000, 4.600% senior notes due 2033        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000   $ 500,000,000  
Interest rate (as a percent) 4.60% 4.60% 4.60%  
Long-term debt $ 496,629,000     0
$500,000, 5.125% senior notes due 2034        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000      
Interest rate (as a percent) 5.125% 5.125%    
Long-term debt $ 495,545,000     495,104,000
$700,000, 5.150% senior notes due 2035        
Debt Instrument [Line Items]        
Principal amount $ 700,000,000      
Interest rate (as a percent) 5.15% 5.15%    
Long-term debt $ 695,324,000     694,909,000
$1,000,000, 4.900% senior notes due 2036        
Debt Instrument [Line Items]        
Principal amount $ 1,000,000,000   $ 1,000,000,000  
Interest rate (as a percent) 4.90% 4.90% 4.90%  
Long-term debt $ 989,938,000     0
$500,000, 4.250% senior notes due 2045        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000      
Interest rate (as a percent) 4.25% 4.25%    
Long-term debt $ 495,955,000     495,792,000
$500,000, 4.300% senior notes due 2047        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000      
Interest rate (as a percent) 4.30% 4.30%    
Long-term debt $ 494,287,000     494,088,000
$500,000, 5.650% senior notes due 2056        
Debt Instrument [Line Items]        
Principal amount $ 500,000,000   $ 500,000,000  
Interest rate (as a percent) 5.65% 5.65% 5.65%  
Long-term debt $ 491,713,000     0
Alliance Healthcare debt        
Debt Instrument [Line Items]        
Long-term debt 87,990,000     1,424,000
Less current portion 87,990,000     1,424,000
OneOncology physician notes        
Debt Instrument [Line Items]        
Long-term debt 365,163,000     0
Less current portion 58,200,000     0
Nonrecourse debt        
Debt Instrument [Line Items]        
Long-term debt 231,894,000     181,751,000
Less current portion $ 115,354,000     $ 116,361,000