Business Segment Information - Schedule of Reportable Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Total segment cost of goods sold	$ 309,854,280	$ 284,048,570	$ 253,213,918
Total segment operating expenses	6,991,889	6,092,788	5,722,842
Total segment operating income	2,628,601	2,175,249	2,340,731
Total depreciation and amortization	1,051,075	1,091,974	963,904
Total capital expenditures	667,981	487,173	458,359
U.S. Healthcare Solutions
Segment Reporting Information [Line Items]
Total capital expenditures	399,518	273,715	268,069
International Healthcare Solutions
Segment Reporting Information [Line Items]
Total capital expenditures	268,463	213,458	190,290
Operating segments
Segment Reporting Information [Line Items]
Total segment cost of goods sold	310,117,957	284,217,555	253,161,448
Total segment operating income	4,222,973	3,648,256	3,289,121
Operating segments | U.S. Healthcare Solutions
Segment Reporting Information [Line Items]
Total segment cost of goods sold	283,076,597	258,916,313	228,938,102
Total segment operating expenses	4,330,727	3,488,237	3,224,557
Total segment operating income	3,574,699	2,934,877	2,596,559
Total depreciation and amortization	352,602	298,683	292,814
Operating segments | International Healthcare Solutions
Segment Reporting Information [Line Items]
Total segment cost of goods sold	27,050,982	25,306,564	24,227,832
Total segment operating expenses	2,667,067	2,607,599	2,498,285
Total segment operating income	648,274	713,379	692,562
Total depreciation and amortization	145,445	132,999	120,044
Segment reconciling items
Segment Reporting Information [Line Items]
Acquisition-related intangibles amortization	553,028	660,292	551,046
Intersegment eliminations
Segment Reporting Information [Line Items]
Total segment cost of goods sold	(9,622)	(5,322)	(4,486)
Total segment operating expenses	$ (5,905)	$ (3,048)	$ 0