Business Segment Information - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) segment	Jun. 30, 2025 USD ($)
Segment Reporting [Line Items]
Sales | $	$ 2,313	$ 2,144	$ 6,657	$ 6,026
Number of operating segments | segment			3
Number of reportable segments | segment			3
Systems And Services | Revenue from Contract with Customer Benchmark | Customer Concentration Risk
Segment Reporting [Line Items]
Total sales (as a percent)	20.00%	20.00%	20.00%	20.00%
UNITED STATES
Segment Reporting [Line Items]
Sales | $	$ 1,377	$ 1,190	$ 3,918	$ 2,242