Schedule II Valuation and Qualifying Accounts Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2015
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 55		$ 48		$ 58
Additions Charged to Expense		7		9		8
Additions Charged to Other Accounts		39		13		18
Other Changes	[1]	(7)		(15)		(36)
Balance at End of Period		94		55		48
Allowance for Deferred Tax Assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		165	[2],[3]	112	[3]	106
Additions Charged to Expense		6	[2]	1	[3]	0
Additions Charged to Other Accounts		7	[2]	52	[3]	9
Other Changes	[1]	(70)	[2]	0	[3]	(3)
Balance at End of Period		$ 108	[2]	$ 165	[2],[3]	$ 112	[3]

[1] (A) Other changes related to allowance for doubtful accounts primarily includes write-offs of uncollectible trade receivables, net of recoveries. Other Changes also includes the impact of foreign currency translation adjustments.

[2] (B) The decrease in the valuation allowance was primarily due to the utilization of federal and state loss carryforwards as a result of recognizing the gain on the sale of our PMD business. This benefit was recorded in discontinued operations. See Note 3, Discontinued Operations, for additional information.

[3] (C) The increase in the valuation allowance was primarily due to the loss recorded on the exit from the Energy-from-Waste business. These costs were recorded in discontinued operations. See Note 3, Discontinued Operations, for additional information.