Other Deductions, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Other deductions, net [Line Items]
Amortization of intangibles (intellectual property and customer relationships)	$ 300	$ 239	$ 238
Restructuring costs	150	284	95
Other	(132)	9	(8)
Other deductions, net	318	532	325
Amortization of intangible assets	470	369	$ 359
Gain (loss) from an investment	21
Gain (loss) from acquiring the remaining interest of an equity investment	17
Equity Method Investment, Realized Gain (Loss) on Disposal	31
Special advisory fees		$ 13
Order or Production Backlog [Member] | Open Systems International, Inc. [Member]
Other deductions, net [Line Items]
Amortization of intangible assets	$ 30