Restructuring and Related Costs - Schedule of Restructuring Reserve by Type of Cost (Details) $ in Millions	12 Months Ended
	Sep. 30, 2025 USD ($)
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 164
Utilized—cash	(87)
Utilized—noncash	(40)
Other	7
Restructuring reserve, ending balance	44
Employee Severance and Termination Benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	100
Utilized—cash	(69)
Utilized—noncash	0
Other	8
Restructuring reserve, ending balance	39
Long-Lived Asset Impairments
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	40
Utilized—cash	0
Utilized—noncash	(40)
Other	0
Restructuring reserve, ending balance	0
Other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	24
Utilized—cash	(18)
Utilized—noncash	0
Other	(1)
Restructuring reserve, ending balance	$ 5