Other Financial Data (Accrued Expenses) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Customer advances (contract liabilities)	$ 730	$ 583
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued expenses	Accrued expenses
Other Current Liabilities [Member]
Customer advances (contract liabilities)	$ 730	$ 583
Employee compensation	690	577
Operating lease liabilities (current)	155	148
Product warranty	$ 146	$ 148