Goodwill and Other Intangible Assets - Schedule of Change in the Carrying Value of Goodwill by Reportable Segment (Details) $ in Thousands	9 Months Ended
Jun. 30, 2026 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 13,676,520
Reallocated goodwill	0
Goodwill recognized in connection with acquisitions	4,298,517
Purchase accounting adjustments	3,793
Goodwill impairment	(165,665)
Goodwill reclassified to assets held for sale (Note 3)	(1,255,231)
Foreign currency translation	(42,477)
Goodwill, ending balance	16,515,457
Other
Goodwill [Roll Forward]
Goodwill, beginning balance	0
Reallocated goodwill	1,421,428
Goodwill recognized in connection with acquisitions	0
Purchase accounting adjustments	0
Goodwill impairment	(165,665)
Goodwill reclassified to assets held for sale (Note 3)	(1,255,231)
Foreign currency translation	(532)
Goodwill, ending balance	0
U.S. Healthcare Solutions \| Operating Segments
Goodwill [Roll Forward]
Goodwill, beginning balance	11,104,990
Reallocated goodwill	(1,421,428)
Goodwill recognized in connection with acquisitions	4,229,009
Purchase accounting adjustments	3,793
Goodwill impairment	0
Goodwill reclassified to assets held for sale (Note 3)	0
Foreign currency translation	0
Goodwill, ending balance	13,916,364
International Healthcare Solutions \| Operating Segments
Goodwill [Roll Forward]
Goodwill, beginning balance	2,571,530
Reallocated goodwill	0
Goodwill recognized in connection with acquisitions	69,508
Purchase accounting adjustments	0
Goodwill impairment	0
Goodwill reclassified to assets held for sale (Note 3)	0
Foreign currency translation	(41,945)
Goodwill, ending balance	$ 2,599,093

Goodwill, Reclassified To Assets Held For Sale

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