Accounts Payable, Accrued Liabilities and Other Liabilities - Components of Other Long-Term Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Payables And Accruals [Abstract]
Employee benefit plan liabilities	$ 92	$ 91
Operating lease liabilities	89
Non-current tax liabilities	9	12
Other accrued liabilities	96	103
Total	$ 286	$ 206