Commitments and Contingencies - Transactions with Nokia (Details) $ in Millions	6 Months Ended
Mar. 31, 2020 USD ($)
Indemnification Agreement
Loss Contingencies [Line Items]
Threshold amount of contribution and distribution agreement	$ 50

The Contribution And Distribution Agreement provides that each party to the agreement will share specified portions of contingent liabilities based upon agreed upon percentages related to the business of the other party that exceed this amount.

No definition available.

Name:	avya_ThresholdAmountContributionAndDistributionAgreement
Namespace Prefix:	avya_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration