Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018		Sep. 30, 2017
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 91	$ 94		$ 55
Additions Charged to Expense		12	17		7
Additions Charged to Other Accounts		37	7		39
Other Changes	[1]	(52)	(27)		(7)
Balance at End of Period		88	91		94
Allowance for Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		105	108	[2]	165	[2]
Additions Charged to Expense		5	3		6	[2]
Additions Charged to Other Accounts		2	4		7	[2]
Other Changes	[1]	(20)	(10)		(70)	[2]
Balance at End of Period		$ 92	$ 105		$ 108	[2]

[1] 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] 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 4, Discontinued Operations, for additional information.