Restructuring Activities - Schedule of Restructuring Activity (Details) - Employee Severance - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Restructuring Reserve [Roll Forward]
Balance at September 30, 2019	$ 9	$ 0
Expenses recognized during the period	1	13
Payments for Restructuring	(8)	(3)
Payments	(8)	(3)
Changes in estimates	(1)	(1)
Balance at September 30, 2020	$ 1	$ 9

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

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- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

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- Definition

Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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