Business Restructuring Reserves and Programs (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 12,000,000	$ 5,000,000	$ 22,000,000	$ 17,000,000
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning balance			44,000,000
Cash payments			(18,000,000)
Impact of foreign currency fluctuations			(3,000,000)
Restructuring Reserve, ending balance	30,000,000		30,000,000
Fiscal 2020 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			0
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning balance			14,000,000
Cash payments			(3,000,000)
Impact of foreign currency fluctuations			(1,000,000)
Restructuring Reserve, ending balance	10,000,000		10,000,000
Fiscal 2019 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			7,000,000
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning balance			0
Cash payments			(5,000,000)
Impact of foreign currency fluctuations			0
Restructuring Reserve, ending balance	2,000,000		2,000,000
Fiscal 2008-2018 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			0
Restructuring Reserve [Roll Forward]
Restructuring Reserve, beginning balance			30,000,000
Cash payments			(10,000,000)
Impact of foreign currency fluctuations			(2,000,000)
Restructuring Reserve, ending balance	18,000,000		18,000,000
Employee Separation Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	3,000,000	4,000,000	7,000,000	6,000,000
Facility Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 9,000,000	$ 1,000,000	15,000,000	$ 11,000,000
Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 7,000,000

Avaya Holdings Corp. 10-Q