Basis of Presentation and Summary of Significant Accounting Policies - Net Periodic Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales	$ 4,031	$ 4,314	$ 8,009	$ 8,317
Gross profit	197	282	377	483
Earnings (loss) before interest and income taxes	(22)	(141)	32	(40)
Other pension expense (income)	$ 0	(7)	$ (2)	(8)
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other pension expense (income)		6		6
Restatement Adjustment | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales		2		3
Gross profit		(2)		(3)
Earnings (loss) before interest and income taxes		(7)		(8)
Other pension expense (income)		7		8
EMEA | Restatement Adjustment | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjusted EBITDA		$ 1		$ 2