Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Related Party Transactions [Abstract]
Net sales to related parties	$ 92	$ 99
Purchases from related parties	173	$ 137
Accounts receivable due from related parties	108		$ 91
Accounts payable due to related parties	$ 107		$ 102