Other Assets - Summary of Other Assets (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Other Assets, Noncurrent [Abstract]
Prepaid pension costs	$ 201	$ 191
Deferred income tax assets	42	42
Investments in non-consolidated joint ventures	142	132
Other	259	263
Other assets	$ 644	$ 628