Revenue Recognition - Narrative (Details) - USD ($) $ in Millions			3 Months Ended		6 Months Ended
	Oct. 01, 2019	Oct. 01, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Capitalized Contract Cost to Obtain a Contract, Amortization				$ 24		$ 46
Capitalized Contract Cost to Fulfill, Amortization			$ 6	6	$ 20	20
Revenue recognized that was previously recorded as a contract liability	$ 405	$ 396
Revenue, Remaining Performance Obligation, Amount			2,500		2,500
Selling, General and Administrative Expenses
Disaggregation of Revenue [Line Items]
Capitalized Contract Cost to Obtain a Contract, Amortization			$ 34	23	$ 66	43
Cost of Sales [Member]
Disaggregation of Revenue [Line Items]
Capitalized Contract Cost to Obtain a Contract, Amortization				$ 1		$ 3