Divestitures - Summary of Assets and Liabilities Held for Sale (Details) - USD ($) $ in Millions		Mar. 31, 2019	Sep. 30, 2018
Divestitures [Abstract]
Accounts receivable, net	[1]	$ 173	$ 159
Inventories		67	67
Net property, plant and equipment		254
Goodwill		143
Intangibles		38
Deferred income taxes		7
Other assets		57	14
Current assets held for sale		739	240
Net property, plant and equipment			254
Goodwill			144
Intangibles			40
Deferred income taxes			7
Other assets			32
Noncurrent assets held for sale			477
Trade and other payables		112	152
Employee benefit obligations		22
Accrued expenses and other liabilities		10	11
Other liabilities		3
Current liabilities held for sale		$ 147	163
Employee benefit obligations			23
Other liabilities			3
Noncurrent liabilities held for sale			$ 26

[1] Accounts receivable included an allowance for doubtful accounts of $3 million at both March 31, 2019 and September 30, 2018.