Avaya (AVYA) 10-Q 2 Mar 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Dec. 31, 2017	Mar. 02, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Avaya Holdings Corp.
Entity Central Index Key	1,418,100
Current Fiscal Year End Date	--09-30
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		109,794,137

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
REVENUE
Products	$ 71
Services	77
TOTAL REVENUES	148
Products:
Costs	33
Amortization of technology intangible assets	7
Services	30
TOTAL COST OF REVENUE	70
GROSS PROFIT	78
OPERATING EXPENSES
Selling, general and administrative	50
Research and development	9
Amortization of intangible assets	7
Restructuring charges, net	10
TOTAL OPERATING EXPENSES	76
OPERATING INCOME	2
Interest expense	(9)
Other (expense) income, net	(2)
Reorganization items, net	0
(LOSS) INCOME BEFORE INCOME TAXES	(9)
Benefit from (provision for) income taxes	246
NET INCOME (LOSS)	$ 237
Net income (loss) per share:
Basic (USD per share)	$ 2.16
Diluted (USD per share)	$ 2.15
Weighted average shares outstanding:
Basic (shares)	109.8
Diluted (shares)	110.3
Predecessor
REVENUE
Products		$ 253	$ 401
Services		351	474
TOTAL REVENUES		604	875
Products:
Costs		84	145
Amortization of technology intangible assets		3	5
Services		155	190
TOTAL COST OF REVENUE		242	340
GROSS PROFIT		362	535
OPERATING EXPENSES
Selling, general and administrative		264	336
Research and development		38	62
Amortization of intangible assets		10	57
Restructuring charges, net		14	10
TOTAL OPERATING EXPENSES		326	465
OPERATING INCOME		36	70
Interest expense		(14)	(174)
Other (expense) income, net		(2)	4
Reorganization items, net		3,416	0
(LOSS) INCOME BEFORE INCOME TAXES		3,436	(100)
Benefit from (provision for) income taxes		(459)	(3)
NET INCOME (LOSS)		$ 2,977	$ (103)
Net income (loss) per share:
Basic (USD per share)		$ 5.19	$ (0.22)
Diluted (USD per share)		$ 5.19	$ (0.22)
Weighted average shares outstanding:
Basic (shares)		497.3	497
Diluted (shares)		497.3	497

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Net income (loss)	$ 237
Other comprehensive (loss) income:
Pension, post-retirement and postemployment benefit-related items, net of income taxes of $58 for the period from October 1, 2017 through December 15, 2017 and $6 for the three months ended December 31, 2016	0
Cumulative translation adjustment, net of income taxes of $(4) for the three months ended December 31, 2016	(13)
Other comprehensive (loss) income	(13)
Cancellation of Predecessor equity	0
Total comprehensive income (loss)	$ 224
Predecessor
Net income (loss)		$ 2,977	$ (103)
Other comprehensive (loss) income:
Pension, post-retirement and postemployment benefit-related items, net of income taxes of $58 for the period from October 1, 2017 through December 15, 2017 and $6 for the three months ended December 31, 2016		655	14
Cumulative translation adjustment, net of income taxes of $(4) for the three months ended December 31, 2016		3	23
Other comprehensive (loss) income		658	37
Cancellation of Predecessor equity		790	0
Total comprehensive income (loss)		$ 4,425	$ (66)

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - Phantom - Predecessor - USD ($) $ in Millions	2 Months Ended	3 Months Ended
	Dec. 15, 2017	Dec. 31, 2016
Pension, post-retirement and postemployment benefit-related items, net of income taxes	$ 58	$ 6
Cumulative translation adjustment, net of income taxes		$ (4)

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 417
Accounts receivable, net	413
Inventory	124
Other current assets	230
TOTAL CURRENT ASSETS	1,184
Property, plant and equipment, net	306
Deferred income taxes, net	31
Intangible assets, net	3,421
Goodwill	2,632
Other assets	53
TOTAL ASSETS	7,627
Current liabilities:
Debt maturing within one year	0
Long-term debt, current portion	29
Accounts payable	304
Payroll and benefit obligations	124
Deferred revenue	384
Business restructuring reserve	36
Other current liabilities	153
TOTAL CURRENT LIABILITIES	1,030
Non-current liabilities:
Long-term debt, net of current portion	2,867
Pension obligations	793
Other post-retirement obligations	215
Deferred income taxes, net	444
Business restructuring reserve	34
Other liabilities	377
TOTAL NON-CURRENT LIABILITIES	4,730
LIABILITIES SUBJECT TO COMPROMISE	0
TOTAL LIABILITIES	5,760
Commitments and contingencies (Note 20)
Preferred stock
STOCKHOLDERS' EQUITY (DEFICIT)
Common stock	1
Additional paid-in capital	1,642
Retained earnings (Accumulated deficit)	237
Accumulated other comprehensive loss	(13)
TOTAL STOCKHOLDERS' EQUITY (DEFICIT)	1,867
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)	$ 7,627
Predecessor
Current assets:
Cash and cash equivalents		$ 876
Accounts receivable, net		536
Inventory		96
Other current assets		269
TOTAL CURRENT ASSETS		1,777
Property, plant and equipment, net		200
Deferred income taxes, net		0
Intangible assets, net		311
Goodwill		3,542
Other assets		68
TOTAL ASSETS		5,898
Current liabilities:
Debt maturing within one year		725
Long-term debt, current portion		0
Accounts payable		282
Payroll and benefit obligations		127
Deferred revenue		614
Business restructuring reserve		35
Other current liabilities		90
TOTAL CURRENT LIABILITIES		1,873
Non-current liabilities:
Long-term debt, net of current portion		0
Pension obligations		513
Other post-retirement obligations		0
Deferred income taxes, net		32
Business restructuring reserve		34
Other liabilities		170
TOTAL NON-CURRENT LIABILITIES		749
LIABILITIES SUBJECT TO COMPROMISE		7,705
TOTAL LIABILITIES		10,327
Commitments and contingencies (Note 20)
Predecessor equity awards on redeemable shares		7
STOCKHOLDERS' EQUITY (DEFICIT)
Common stock		0
Additional paid-in capital		2,389
Retained earnings (Accumulated deficit)		(5,954)
Accumulated other comprehensive loss		(1,448)
TOTAL STOCKHOLDERS' EQUITY (DEFICIT)		(5,013)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)		5,898
Predecessor | Convertible Series B preferred stock
Non-current liabilities:
Preferred stock		393
Predecessor | Series A preferred stock
Non-current liabilities:
Preferred stock		$ 184

Condensed Consolidated Balance6

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Dec. 31, 2017	Sep. 30, 2017
Preferred stock, par value (in usd per share)	$ 0.01
Preferred stock, shares authorized	55,000,000
Convertible preferred stock, shares issued	0
Convertible preferred stock, shares outstanding	0
Common stock, par value (in usd per share)	$ 0.01
Common stock, shares authorized	550,000,000
Common stock, shares issued	110,000,000
Common stock, share outstanding	109,794,137
Predecessor
Preferred stock, par value (in usd per share)		$ 0.001
Preferred stock, shares authorized		250,000
Common stock, par value (in usd per share)		$ 0.01
Common stock, shares authorized		750,000,000
Common stock, shares issued		494,768,243
Common stock, share outstanding		494,768,243
Convertible Series B preferred stock | Predecessor
Convertible preferred stock, shares issued		48,922
Convertible preferred stock, shares outstanding		48,922
Series A preferred stock | Predecessor
Convertible preferred stock, shares issued		125,000
Convertible preferred stock, shares outstanding		125,000

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity (Deficit) (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Series A preferred stock	Series B preferred stock	Common Stock	Additional Paid-in Capital	Additional Paid-in CapitalSeries A preferred stock	Additional Paid-in CapitalSeries B preferred stock	(Accumulated Deficit) Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Beginning balance (Predecessor) at Sep. 30, 2016									$ (1,661)
Increase (Decrease) in Stockholders' Equity
Net income (loss) | Predecessor	$ (103)
Other comprehensive (loss) income | Predecessor	37
Cancellation of Predecessor equity | Predecessor	0
Ending balance (Predecessor) at Dec. 31, 2016									(1,624)
Beginning balance (in shares) (Predecessor) at Sep. 30, 2017				494.8
Beginning balance (Predecessor) at Sep. 30, 2017	(5,013)			$ 0	$ 2,389			$ (5,954)	(1,448)
Increase (Decrease) in Stockholders' Equity
Amortization of share-based compensation | Predecessor	3				3
Accrued dividends | Predecessor		$ (2)	$ (4)			$ (2)	$ (4)
Reclassifications to equity awards on redeemable shares | Predecessor	1				1
Net income (loss) | Predecessor	2,977							2,977
Other comprehensive (loss) income | Predecessor	658								658
Cancellation of Predecessor equity | Predecessor	790
Ending balance (in shares) (Predecessor) at Dec. 15, 2017				110
Ending balance (in shares) at Dec. 15, 2017				110
Ending balance (Predecessor) at Dec. 15, 2017	1,642			$ 1	1,641			0	0
Ending balance at Dec. 15, 2017	1,642			$ 1	1,641			0	0
Increase (Decrease) in Stockholders' Equity
Common stock issued for debt (in shares) | Predecessor				103.7
Common stock issued for Predecessor debt | Predecessor	1,549			$ 1	1,548
Common stock issued for PBGC (in shares) | Predecessor				6.1
Common stock issued for Pension Benefit Guaranty Corporation | Predecessor	$ 90				90
Common stock issued for GUC (in shares) | Predecessor				0.2
Common stock issued for GUC (in shares)	0.2
Common stock issued for general unsecured creditors or Predecessor debt | Predecessor	$ 3				3
Balance as of December 15, 2017 (Predecessor) (in shares) | Predecessor				494.8
Balance as of December 15, 2017 (Predecessor) | Predecessor	(1,380)				2,387			(2,977)	(790)
Issuance of Successor common stock	0
Amortization of share-based compensation	1				1
Net income (loss)	237
Other comprehensive (loss) income	(13)								(13)
Cancellation of Predecessor equity	0
Ending balance (in shares) at Dec. 31, 2017				110
Ending balance (Predecessor) at Dec. 31, 2017									(13)
Ending balance at Dec. 31, 2017	$ 1,867			$ 1	$ 1,642			$ 237	$ (13)

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
OPERATING ACTIVITIES:
Net income (loss)	$ 237
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation and amortization	22
Share-based compensation	1
Amortization of debt issuance costs	0
Accretion of debt discount	0
Provision for uncollectible receivables	1
Deferred income taxes, net	(245)
Post-retirement curtailment	0
Loss on disposal of long-lived assets	0
Unrealized gain on foreign currency exchange	(4)
Reorganization items:
Net gain on settlement of Liabilities subject to compromise	0
Payment to PBGC	0
Payment to pension trust	0
Payment of unsecured claims	0
Fresh start adjustments, net	0
Non-cash and financing related reorganization items, net	0
Changes in operating assets and liabilities:
Accounts receivable	5
Inventory	3
Accounts payable	27
Payroll and benefit obligations	(22)
Business restructuring reserve	(3)
Deferred revenue	44
Other assets and liabilities	0
NET CASH PROVIDED BY (USED FOR) OPERATING ACTIVITIES	66
INVESTING ACTIVITIES:
Capital expenditures	(2)
Acquisition of businesses, net of cash acquired	0
Restricted cash	10
Other investing activities, net	0
NET CASH PROVIDED BY (USED FOR) INVESTING ACTIVITIES	8
FINANCING ACTIVITIES:
Proceeds from Term Loan Credit Agreement	0
Repayment of DIP financing	0
Debt issuance costs	0
Repayments of borrowings under sale-leaseback transaction	0
Other financing activities, net	0
NET CASH PROVIDED BY (USED FOR) FINANCING ACTIVITIES	0
Effect of exchange rate changes on cash and cash equivalents	3
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	77
Cash and cash equivalents at beginning of period	340
Cash and cash equivalents at end of period	417	$ 340
First lien debt
FINANCING ACTIVITIES:
Repayment of long-term debt	0
Foreign ABL
FINANCING ACTIVITIES:
Repayments of lines of credit	0
Domestic ABL
FINANCING ACTIVITIES:
Repayments of lines of credit	0
Long-term debt, including adequate protection payments
FINANCING ACTIVITIES:
Repayment of long-term debt	0
Senior Secured Credit Agreement
FINANCING ACTIVITIES:
Repayments of lines of credit	0
Predecessor
OPERATING ACTIVITIES:
Net income (loss)		2,977	$ (103)
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation and amortization		31	90
Share-based compensation		0	2
Amortization of debt issuance costs		0	36
Accretion of debt discount		0	25
Provision for uncollectible receivables		(1)	1
Deferred income taxes, net		455	(1)
Post-retirement curtailment		0	(4)
Loss on disposal of long-lived assets		1	0
Unrealized gain on foreign currency exchange		0	(8)
Reorganization items:
Net gain on settlement of Liabilities subject to compromise		(1,804)	0
Payment to PBGC		(340)	0
Payment to pension trust		(49)	0
Payment of unsecured claims		(58)	0
Fresh start adjustments, net		(1,671)	0
Non-cash and financing related reorganization items, net		26	0
Changes in operating assets and liabilities:
Accounts receivable		14	54
Inventory		(2)	1
Accounts payable		(40)	(22)
Payroll and benefit obligations		16	(56)
Business restructuring reserve		(7)	(18)
Deferred revenue		28	1
Other assets and liabilities		(16)	(42)
NET CASH PROVIDED BY (USED FOR) OPERATING ACTIVITIES		(440)	(44)
INVESTING ACTIVITIES:
Capital expenditures		(13)	(14)
Acquisition of businesses, net of cash acquired		0	(4)
Restricted cash		21	0
Other investing activities, net		0	3
NET CASH PROVIDED BY (USED FOR) INVESTING ACTIVITIES		8	(15)
FINANCING ACTIVITIES:
Proceeds from Term Loan Credit Agreement		2,896	0
Repayment of DIP financing		(725)	0
Debt issuance costs		(97)	0
Repayments of borrowings under sale-leaseback transaction		(4)	(5)
Other financing activities, net		0	(1)
NET CASH PROVIDED BY (USED FOR) FINANCING ACTIVITIES		(102)	(57)
Effect of exchange rate changes on cash and cash equivalents		(2)	(11)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS		(536)	(127)
Cash and cash equivalents at beginning of period	$ 340	876	336
Cash and cash equivalents at end of period		340	209
Predecessor | First lien debt
FINANCING ACTIVITIES:
Repayment of long-term debt		(2,061)	0
Predecessor | Foreign ABL
FINANCING ACTIVITIES:
Repayments of lines of credit		0	(5)
Predecessor | Domestic ABL
FINANCING ACTIVITIES:
Repayments of lines of credit		0	(22)
Predecessor | Long-term debt, including adequate protection payments
FINANCING ACTIVITIES:
Repayment of long-term debt		(111)	(6)
Predecessor | Senior Secured Credit Agreement
FINANCING ACTIVITIES:
Repayments of lines of credit		$ 0	$ (18)

Background and Basis Of Present

Background and Basis Of Presentation	3 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis Of Presentation	Background and Basis of Presentation Background Avaya Holdings Corp. (the "Parent" or "Avaya Holdings"), together with its consolidated subsidiaries (collectively, the “Company” or “Avaya”), is a leading global provider of software and associated hardware and services for contact center and unified communications, offered on-premises, in the cloud, or as a hybrid solution. Avaya provides the mission-critical, real-time communication applications for small businesses to large multinational enterprises and government organizations. Currently, the Company manages its business operations in two segments, Global Communications Solutions ("GCS") representing the Company's products portfolio, and Avaya Global Services ("AGS") representing the Company's services portfolio. The Company sells directly through its worldwide sales force and indirectly through its global network of channel partners, including distributors, service providers, dealers, value-added resellers, system integrators and business partners that provide sales and services support. Basis of Presentation Avaya Holdings has no material assets or standalone operations other than its ownership in Avaya Inc. and its subsidiaries. The accompanying unaudited interim Condensed Consolidated Financial Statements as of December 31, 2017 and for the period from December 16, 2017 through December 31, 2017 , the period from October 1, 2017 through December 15, 2017 and the three months ended December 31, 2016 , reflect the operating results of Avaya Holdings and its consolidated subsidiaries, and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial statements, and should be read in conjunction with the Consolidated Financial Statements and other financial information for the fiscal year ended September 30, 2017 , included in Amendment No. 3 to the Company’s Form 10 filed with the SEC on January 10, 2018. In management’s opinion, these unaudited interim Condensed Consolidated Financial Statements reflect all adjustments, consisting of normal and recurring adjustments, necessary to present fairly the results of operations, financial position and cash flows for the periods indicated. The condensed consolidated results of operations for the interim periods reported are not necessarily indicative of our results for the entire fiscal year. Management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and revenue and expenses during the periods reported. These estimates include assessing the collectability of accounts receivable, sales returns and allowances, the use and recoverability of inventory, the realization of deferred tax assets, business restructuring reserves, pension and post-retirement benefit costs, the fair value of equity compensation, the fair value of assets and liabilities in connection with fresh start accounting as well as those acquired in business combinations, the recoverability of long-lived assets, useful lives and impairment of tangible and intangible assets including goodwill, the amount of exposure from potential loss contingencies, and fair value measurements, among others. The markets for the Company’s products are characterized by intense competition, rapid technological development and frequent new product introductions, all of which could affect the future recoverability of the Company’s assets. Estimates and assumptions are reviewed periodically and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Actual results could differ from these estimates. On January 19, 2017 (the “Petition Date”), Avaya Holdings, together with certain of its affiliates, namely Avaya CALA Inc., Avaya EMEA Ltd., Avaya Federal Solutions, Inc., Avaya Holdings LLC, Avaya Holdings Two, LLC, Avaya Inc., Avaya Integrated Cabinet Solutions Inc., Avaya Management Services Inc., Avaya Services Inc., Avaya World Services Inc., Octel Communications LLC, Sierra Asia Pacific Inc., Sierra Communication International LLC, Technology Corporation of America, Inc., Ubiquity Software Corporation, VPNet Technologies, Inc., and Zang, Inc. (the “Debtors”), filed voluntary petitions for relief (the “Bankruptcy Filing”) under Chapter 11 of the United States Bankruptcy Code (the “Bankruptcy Code’) in the United States Bankruptcy Court for the Southern District of New York (the “Bankruptcy Court’). The cases were jointly administered as Case No. 17-10089 (SMB). The Debtors operated their businesses as "debtors-in-possession" under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of Chapter 11 of the Bankruptcy Code and the orders of the Bankruptcy Court until their emergence from bankruptcy on December 15, 2017. Subsequent to the Petition Date, all expenses, gains and losses directly associated with the reorganization proceedings were reported as Reorganization items, net in the accompanying Condensed Consolidated Statements of Operations. In addition, Liabilities subject to compromise during Chapter 11 proceedings were distinguished from liabilities of the non-debtors and from post-petition liabilities in the accompanying Condensed Consolidated Balance Sheets. The Company's other subsidiaries that were not part of the Bankruptcy Filing ("non-debtors") continued to operate in the ordinary course of business. Upon emergence from bankruptcy on December 15, 2017 (the "Emergence Date"), the Company applied fresh start accounting, which resulted in a new basis of accounting and the Company becoming a new entity for financial reporting purposes. As a result of the application of fresh start accounting and the effects of the implementation of the Second Amended Joint Plan of Reorganization filed by the Debtors on October 24, 2017 and approved by the Bankruptcy Court on November 28, 2017 (the "Plan of Reorganization"), the consolidated financial statements after the Emergence Date, are not comparable with the consolidated financial statements on or before that date. Refer to Note 5, "Fresh Start Accounting," for additional information. The accompanying Condensed Consolidated Financial Statements of the Company have been prepared on a basis that assumes that the Company will continue as a going concern and contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. During the Chapter 11 proceedings, the Company's ability to continue as a going concern was contingent upon its ability to comply with the financial and other covenants contained in its debtor-in-possession credit agreement, the Bankruptcy Court's approval of the Company's Plan of Reorganization and the Company's ability to successfully implement the Plan of Reorganization, among other factors. As a result of the execution of the Plan of Reorganization, there is no longer substantial doubt about the Company's ability to continue as a going concern. References to "Successor" or "Successor Company" relate to the financial position and results of operations of the reorganized Avaya Holdings after the Emergence Date. References to "Predecessor" or "Predecessor Company" refer to the financial position and results of operations of Avaya Holdings on or before the Emergence Date.

Accounting Policy Changes

Accounting Policy Changes	3 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Accounting Policy Changes	Accounting Policy Changes The Company emerged from bankruptcy on December 15, 2017 , and qualified for fresh start accounting. Fresh start accounting allows a company to set new accounting policies for the successor company independent of those followed by the predecessor company. As such, the following are the accounting policy changes the Successor Company has adopted. Fair Value of Equity Awards Successor Accounting Policy: The Black-Scholes-Merton option pricing model ("Black-Scholes") replaced the Cox-Ross-Rubinstein ("CRR") binomial option pricing model in calculating the fair value of equity awards, including the fair value of warrants to purchase common stock. In addition to the change in option pricing models, the Company now accounts for forfeitures as incurred. Predecessor Accounting Policy: The CRR binomial option pricing model was utilized to determine the grant date fair values of the equity awards, including the fair value of the Preferred Series A and B Stock warrants. Forfeitures was an input assumption in the valuation model. Uncollected Deferred Revenue Successor Accounting Policy: The Company does not recognize deferred revenue relating to any sales transactions that have been billed, but for which the related account receivable has not yet been collected. The aggregate amount of unrecognized accounts receivable and deferred revenue was $100 million at December 31, 2017 . Predecessor Accounting Policy: The Company recorded the deferred revenue and related collectible accounts receivable in its consolidated balance sheets. Foreign Currency Successor Accounting Policy: Income and expense of non-U.S. dollar functional currency subsidiaries are translated into U.S. dollars using an average rate for the period. Predecessor Accounting Policy: Income and expense of non-U.S. dollar functional currency subsidiaries are translated into U.S. dollars at the spot rate for the transaction.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-09, "Improvements to Employee Share-Based Payment Accounting." This standard simplifies the accounting for share-based payments and their presentation in the statements of cash flows as well as the income tax effects of share-based payments. The Company adopted this standard as of October 1, 2017 on a prospective basis. The adoption of this standard did not have a material impact on its Condensed Consolidated Financial Statements. In March 2017, the FASB issued ASU No. 2017-07, "Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost." This standard changes how employers that sponsor defined benefit pension and other post-retirement benefit plans present net periodic benefit cost in the income statement. This amendment requires that the service cost component be disaggregated from the other components of pension and post-retirement benefit costs on the income statement. The service cost component is reported in the same line items as other compensation costs and the other components of pension and post-retirement benefit costs (including interest cost, expected return on plan assets, amortization and curtailments and settlements) are reported in Other income (expense), net in the Company's Condensed Consolidated Financial Statements. The Company early adopted this accounting standard as of October 1, 2017. Changes to the Condensed Consolidated Financial Statements have been applied retrospectively. As a result, the Company reclassified $(6) million of other pension and post-retirement benefit costs to other income (expense), net for the three months ended December 31, 2016 (Predecessor). For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company recorded $1 million and $(8) million , respectively, of other pension and post-retirement benefit costs in other income (expense), net. Recent Standards Not Yet Effective In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers.” This standard supersedes most of the current revenue recognition guidance under GAAP and is intended to improve and converge with international standards the financial reporting requirements for revenue recognition. The core principle of the new guidance is that an entity should recognize revenue to depict the transfer of control of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. New disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers are also required. Subsequently, the FASB issued several standards that clarified certain aspects of the standard but did not change the original standard. This new guidance is effective for the Company beginning in the first quarter of fiscal 2019. The ASU may be applied retrospectively (a) to each reporting period presented or (b) with the cumulative effect in retained earnings at the beginning of the adoption period. We currently anticipate adoption of the new standard effective October 1, 2018 using the modified retrospective method whereby the cumulative effect is recorded to retained earnings at the beginning of the adoption period. Adoption of the standard is dependent on completion of a detailed accounting assessment, the success of the design and implementation phase for changes to the Company's processes, internal controls and system functionality and the completion of our analysis of information necessary to assess the overall impact of adoption of this guidance on our consolidated financial statements. We continue to make progress on the accounting assessment and implementation phases to identify and implement the required changes to accounting policies and disclosures in our consolidated financial statements. We have reached preliminary conclusions on certain accounting assessments and we will continue to monitor and assess the impact of changes to the standard and interpretations as they become available. We expect revenue recognition related to our stand-alone product shipments and maintenance services to remain substantially unchanged. However, we continue to evaluate our preliminary conclusion and assess the impact on our other sources of revenue recognition.

Emergence from Voluntary Reorga

Emergence from Voluntary Reorganization under Chapter 11 Proceedings	3 Months Ended
	Dec. 31, 2017
Reorganizations [Abstract]
Emergence From Voluntary Reorganization Under Chapter 11 Proceedings	Emergence from Voluntary Reorganization under Chapter 11 Proceedings Plan of Reorganization On November 28, 2017 , the Bankruptcy Court entered an order confirming the Plan of Reorganization. On the Emergence Date, the Plan of Reorganization became effective and the Debtors emerged from bankruptcy. On or following the Emergence Date and pursuant to the terms of the Plan of Reorganization, the following occurred: • Debtor-in-Possession Credit Agreement. The Company paid in full the debtor-in-possession credit agreement (the "DIP Credit Agreement") in the amount of $725 million ; • Predecessor Equity and Indebtedness. The Debtors' obligations under stock certificates, equity interests, and / or any other instrument or document directly or indirectly evidencing or creating any indebtedness or obligation of, or ownership interest in, the Debtors or giving rise to any claim or equity interest were cancelled, except as provided under the Plan of Reorganization; • Successor Equity. The Company's certificate of incorporation was amended and restated to authorize the issuance of 605.0 million shares of Successor Company stock, consisting of 55.0 million shares of preferred stock, par value $0.01 per share, and 550.0 million shares of common stock, par value $0.01 per share, of which 110.0 million shares of common stock were issued (as discussed below); • Exit Financing. The Successor Company entered into (1) a term loan credit agreement ("the Term Loan Credit Agreement") for a principal amount of $2,925 million maturing on December 15, 2024 , and (2) a $300 million asset-based revolving credit facility (the "ABL Credit Agreement") maturing on December 15, 2022 ; • First Lien Debt Claims. All of the Predecessor Company's outstanding obligations under the variable rate term B-3, B-4, B-6, and B-7 loans and the 7% and 9% senior secured notes (collectively, the "Predecessor first lien obligations") were cancelled, and the holders of claims under the Predecessor first lien obligations received 99.3 million shares of Successor Company common stock. In addition, the holders of the Predecessor first lien obligations received cash in the amount of $2,061 million ; • Second Lien Debt Claims. All the Predecessor Company's outstanding obligations under the 10.50% senior secured notes (the "Predecessor second lien obligations") were cancelled, and the holders of claims under the Predecessor second lien obligations received 4.4 million shares of Successor Company common stock. In addition, holders of the Predecessor second lien obligations received warrants to purchase 5.6 million shares of Successor Company common stock at an exercise price of $25.55 per warrant (the "Warrants"); • Claims of Pension Benefit Guaranty Corporation ("PBGC"). The Predecessor Company's outstanding obligations under the Avaya Inc. Pension Plan for Salaried Employees ("APPSE") were terminated and transferred to the PBGC. The PBGC received 6.1 million shares of Successor Company common stock and $340 million in cash; and • General Unsecured Claims. Holders of the Predecessor Company's general unsecured claims will receive their pro rata share of the general unsecured recovery pool. A liquidating trust was established in the amount of $58 million for the benefit of the general unsecured claims. Included in the 110.0 million Successor Company common stock issued are 0.2 million additional shares of common stock that have been issued (but are not outstanding) for the benefit of the general unsecured creditors. The general unsecured creditors will receive a total of $58 million in cash and common stock. Any excess cash and / or common stock not distributed to the general unsecured creditors will be distributed to the holders of the Predecessor first lien obligations. Section 363 Asset Sales In July 2017, the Company sold its networking business ("Networking" or the "Networking business") to Extreme Networks, Inc. ("Extreme"). The Networking business was comprised primarily of certain assets of the Company's Networking segment (which prior to the sale was a separate operating segment), along with the maintenance and professional services of the Networking business, which were part of the AGS segment. Under a Transition Services Agreement ("TSA"), the Company provides administrative services to Extreme for process support, maintenance services and product logistics on a fee basis. While the TSA can expire sooner, the agreement terminates after 2 years . Fresh Start Accounting In connection with the Company's emergence from bankruptcy and in accordance with FASB Accounting Standards Codification ("ASC") 852, "Reorganizations" ("ASC 852"), the Company applied the provisions of fresh start accounting to its Condensed Consolidated Financial Statements on the Emergence Date. The Company was required to use fresh start accounting since (i) the holders of existing voting shares of the Predecessor Company received less than 50% of the voting shares of the emerging entity and (ii) the reorganization value of the Company's assets immediately prior to confirmation of the Plan of Reorganization was less than the post-petition liabilities and allowed claims. ASC 852 prescribes that with the application of fresh start accounting, the Company allocated its reorganization value to its individual assets based on their estimated fair values in conformity with ASC 805, "Business Combinations". The reorganization value represents the fair value of the Successor Company's assets before considering liabilities. The excess reorganization value over the fair value of identified tangible and intangible assets is reported as goodwill. As a result of the application of fresh start accounting and the effects of the implementation of the Plan of Reorganization, the consolidated financial statements after December 15, 2017 are not comparable with the consolidated financial statements as of or prior to that date. Reorganization Value As set forth in the Plan of Reorganization, the agreed upon enterprise value of the Company was $5,721 million . This value is within the initial range calculated by the Company of approximately $5,100 million to approximately $7,100 million using an income approach. The $5,721 million enterprise value was selected as it was the transaction price agreed to in the global settlement agreement with the Company’s creditor constituencies, including the PBGC. The reorganization value was then determined by adding back liabilities other than interest bearing debt, pension obligations and the deferred tax impact of the reorganization and fresh start adjustments. The following table reconciles the enterprise value to the estimated fair value of the Successor stockholders' equity as of the Emergence Date: (In millions, except per share amount) Enterprise value $ 5,721 Plus: Cash and cash equivalents 340 Less: Minimum cash required for operations (120 ) Fair value of Term Loan Credit Agreement (1) (2,896 ) Fair value of capitalized leases (20 ) Fair value of pension and other post-retirement obligations, net of tax (2) (856 ) Change in net deferred tax liabilities from reorganization (510 ) Fair value of Successor warrants (3) (17 ) Fair value of Successor common stock $ 1,642 Shares issued at December 15, 2017 110.0 Per share value $ 14.93 (1) The fair value of the Term Loan Credit Agreement was determined based on a market approach utilizing market-clearing data on the valuation date in addition to bid/ask prices and was estimated to be 99% of par value. (2) The following assumptions were used when measuring the fair value of the U.S. pension, non-U.S. pension, and post-retirement benefit plans: weighted-average return on assets of 7.75% , 3.80% and 5.90% , and weighted-average discount rate to measure plan obligations of 3.70% , 1.52% and 3.77% , respectively. (3) The fair value of the Warrants was estimated using the Black-Scholes pricing model. The following table reconciles the enterprise value to the estimated reorganization value as of the Emergence Date: (In millions) Enterprise value $ 5,721 Plus: Non-debt current liabilities 955 Non-debt non-current liabilities 2,090 Excess cash and cash equivalents 220 Less: Pension and other post-retirement obligations, net of deferred taxes (856 ) Capital lease obligations (20 ) Change in net deferred tax liabilities from reorganization (510 ) Warrants issued upon emergence (17 ) Reorganization value of Successor assets $ 7,583 Consolidated Balance Sheet The adjustments set forth in the following consolidated balance sheet as of December 15, 2017 reflect the effect of the consummation of the transactions contemplated by the Plan of Reorganization (reflected in the column "Reorganization Adjustments") as well as fair value adjustments as a result of applying fresh start accounting (reflected in the column "Fresh Start Adjustments"). The explanatory notes highlight methods used to determine fair values or other amounts of the assets and liabilities, as well as significant assumptions or inputs. (In millions) Predecessor Company Reorganization Adjustments Fresh Start Adjustments Successor Company December 15, 2017 ASSETS Current assets: Cash and cash equivalents $ 744 $ (404 ) (1) $ — $ 340 Accounts receivable, net 523 — (106 ) (21,29) 417 Inventory 98 — 29 (22) 127 Other current assets 366 (58 ) (2) (66 ) (23) 242 TOTAL CURRENT ASSETS 1,731 (462 ) (143 ) 1,126 Property, plant and equipment, net 194 — 116 (24) 310 Deferred income taxes, net — 48 (3) (17 ) (25) 31 Intangible assets, net 298 — 3,137 (26) 3,435 Goodwill 3,541 — (909 ) (27) 2,632 Other assets 70 6 (4) (27 ) (28) 49 TOTAL ASSETS $ 5,834 $ (408 ) $ 2,157 $ 7,583 LIABILITIES Current liabilities: Debt maturing within one year $ 725 $ (696 ) (5) $ — $ 29 Accounts payable 325 (49 ) (6) — 276 Payroll and benefit obligations 123 23 (7) — 146 Deferred revenue 627 50 (8) (341 ) (29) 336 Business restructuring reserve 35 3 (9) — 38 Other current liabilities 97 65 (6,10) (3 ) (30) 159 TOTAL CURRENT LIABILITIES 1,932 (604 ) (344 ) 984 Non-current liabilities: Long-term debt, net of current portion — 2,771 (11) 96 (31) 2,867 Pension obligations 539 246 (12) — 785 Other post-retirement obligations — 212 (13) — 212 Deferred income taxes, net 28 113 (14) 548 (32) 689 Business restructuring reserve 26 4 (9) 4 (33) 34 Other liabilities 180 233 (8,15) (43 ) (29,34) 370 TOTAL NON-CURRENT LIABILITIES 773 3,579 605 4,957 LIABILITIES SUBJECT TO COMPROMISE 7,585 (7,585 ) (16) — — TOTAL LIABILITIES 10,290 (4,610 ) 261 5,941 Commitments and contingencies Equity awards on redeemable shares 6 (6 ) (17) — — Preferred stock: Series B 397 (397 ) (17) — — Series A 186 (186 ) (17) — — STOCKHOLDERS' (DEFICIT) EQUITY Common stock (Successor) — 1 (18) — 1 Additional paid-in capital (Successor) — 1,641 (18) — 1,641 Common stock (Predecessor) — — — — Additional paid-in capital (Predecessor) 2,387 (2,387 ) (17) — — (Accumulated deficit) retained earnings (5,978 ) 4,872 (19) 1,106 (36) — Accumulated other comprehensive (loss) income (1,454 ) 664 (20) 790 (35) — TOTAL STOCKHOLDERS' (DEFICIT) EQUITY (5,045 ) 4,791 1,896 1,642 TOTAL LIABILITIES AND STOCKHOLDERS' (DEFICIT) EQUITY $ 5,834 $ (408 ) $ 2,157 $ 7,583 Reorganization Adjustments In accordance with the Plan of Reorganization, the following adjustments were made: 1. Sources and Uses of Cash. The following reflects the net cash payments recorded as of the Emergence Date as a result of implementing the Plan of Reorganization: (In millions) Sources: Proceeds from Term Loan Credit Agreement, net of original issue discount $ 2,896 Release of restricted cash 76 Total sources of cash 2,972 Uses: Repayment of DIP Credit Agreement (725 ) Payment of DIP accrued interest (1 ) Cash paid to Predecessor first lien debt-holders (2,061 ) Cash paid to PBGC (340 ) Payment for professional fees escrow account (56 ) Funding payment for Avaya represented employee pension plan (49 ) Payment of accrued professional & administrative fees (27 ) Costs incurred for Term Loan Credit Agreement and ABL Credit Agreement (59 ) Payment for general unsecured claims (58 ) Total uses of cash (3,376 ) Net uses of cash $ (404 ) 2. Other Current Assets. (In millions) Release of restricted cash $ (76 ) Reclassification of prepaid debt issuance costs related to the Term Loan Credit Agreement (42 ) Payment of fees related to the ABL Credit Agreement 5 Restricted cash for bankruptcy related professional fees 55 Total other current assets $ (58 ) 3. Deferred Income Taxes. The adjustment represents the release of the valuation allowance on deferred tax assets for certain non-U.S. subsidiaries which management believes more likely than not will be realized as a result of the bankruptcy reorganization. 4. Other Assets. The adjustment represents the re-establishment of a foreign prepaid tax. 5. Debt Maturing Within One Year. The adjustment represents the net effect of the Company’s repayment of $725 million for the DIP Credit Agreement and Term Loan Credit Agreement principal payments of $29 million due over the next year. 6. Accounts Payable . The net decrease of $49 million includes $50 million for professional fees that were reclassified to Other current liabilities for accrued bankruptcy related professional fees that will be paid from an escrow account and the payment of $3 million of bankruptcy related professional fees, partially offset by reinstatement of $4 million contact cure costs from liabilities subject to compromise. 7. Payroll and Benefi t Obligations. The Company reinstated $23 million of liabilities subject to compromise related to the post-employment and post-retirement benefit obligations. 8. Deferred Revenue. The reinstatement of liabilities subject to compromise was $79 million of which $50 million is included in deferred revenue and $29 million in other liabilities. 9. Business Restructuring Reserve. The reinstatement of liabilities subject to compromise was $7 million , of which $3 million is current and $4 million is non-current. 10. Other Current Liabilities. (In millions) Reclassification of accrued bankruptcy related professional fees $ 50 Reinstatement of other current liabilities 16 Payment of accrued interest on the DIP Credit Agreement (1 ) Total other current liabilities $ 65 11. Exit Financing. In accordance with the Plan of Reorganization, the Company entered into the Term Loan Credit Agreement with a principal amount of $2,925 million maturing seven years from the date of issuance, and the ABL Credit Agreement, which allows borrowings up to an aggregate principal amount of $300 million , subject to borrowing base availability, maturing five years from the date of issuance. (In millions) Term Loan Credit Agreement $ 2,925 Less: Discount (29 ) Upfront and underwriting fees (54 ) Cash received upon emergence from bankruptcy 2,842 Reclassification of debt issuance cost incurred prior to emergence from bankruptcy (42 ) Current portion of Long-term debt (29 ) Long-term debt, net of current portion $ 2,771 12. Pension Obligations. In accordance with the Plan of Reorganization, the Company reinstated from liabilities subject to compromise $295 million related to the Avaya Pension Plan for represented employees and also contributed $49 million to the related pension trust. 13. Other Post-retirement Obligations. Other post-retirement benefit obligations of $212 million were reinstated from liabilities subject to compromise. 14. Deferred Income Taxes . The adjustment represents the reinstatement of the deferred tax liability that was included in liabilities subject to compromise. 15. Other Liabilities . The increase of $233 million primarily relates to the reinstatement of employee benefits, tax liabilities and deferred revenue from liabilities subject to compromise. Also included is the value of the Warrants issued to the holders of the Predecessor second lien obligations on the Emergence Date. 16. Liabilities Subject to Compromise. Liabilities subject to compromise were reinstated or settled as follows in accordance with the Plan of Reorganization: (In millions) Liabilities subject to compromise $ 7,585 Less amounts settled per the Plan of Reorganization Pre-petition first lien debt (4,281 ) Pre-petition second lien debt (1,440 ) Avaya Pension Plan for Salaried Employees (620 ) Amounts reinstated: Accounts payable (4 ) Payroll and benefit obligations (23 ) Deferred revenue (50 ) Business restructuring reserves (7 ) Other current liabilities (16 ) Pension obligations (295 ) Other post-retirement obligations (212 ) Deferred income taxes, net (118 ) Other liabilities (216 ) Total liabilities reinstated at emergence (941 ) General unsecured credit claims (1) (303 ) Liabilities subject to compromise $ — (1) In settlement of allowed general unsecured claims, each claimant will receive a pro-rata distribution of $58 million of the general unsecured claims account. The following table displays the detail on the gain on settlement of liabilities subject to compromise: (In millions) Pre-petition first lien debt $ 734 Pre-petition second lien debt 1,357 Avaya pension plan for salaried employees (514 ) General unsecured creditors' claims 227 Net gain on settlement of Liabilities subject to compromise $ 1,804 17. Cancellation of Predecessor Preferred and Common Stock. All common stock, Series A and B preferred stock and all other equity awards of the Predecessor Company were cancelled on the Emergence Date without any recovery on account thereof. 18. Issuance of Successor Common Stock and Warrants. In settlement of the Company's $5,721 million Predecessor first lien obligations and Predecessor second lien obligations, the holders of the Predecessor first lien obligations received a total of 99.3 million shares of common stock (fair value of $1,486 million ) and $2,061 million in cash and the holders of the Predecessor second lien obligations received a total of 4.4 million shares of common stock (fair value of $66 million ) and 5.6 million of Warrants to purchase additional common shares (fair value of $17 million ). In addition, as part of the Plan of Reorganization, the Company completed a distressed termination of the APPSE in accordance with the Stipulation Settlement with the PBGC, the PBGC received $340 million in cash and 6.1 million shares of common stock (fair value of $90 million ). 19. Accumulated Deficit. (In millions) Accumulated deficit: Net gain on settlement of liabilities subject to compromise $ 1,804 Expense for certain professional fees (26 ) Benefit from income taxes 118 Cancellation of Predecessor equity awards 6 Cancellation of Predecessor Preferred stock Series B 397 Cancellation of Predecessor Preferred stock Series A 186 Cancellation of Predecessor Common stock 2,387 Total $ 4,872 20. Accumulated Comprehensive Loss. The changes to Accumulated comprehensive loss relate to the settlement of the APPSE and the Avaya Supplemental Pension Plan ("ASPP") and the associated taxes. Fresh Start Adjustments At the Emergence Date, the Company met the requirements under ASC 852 for fresh start accounting as (i) the holders of existing voting shares of the Predecessor Company received less than 50% of the voting shares of the emerging entity and (ii) the reorganization value of the Company's assets immediately prior to confirmation was less than the post-petition liabilities and allowed claims. These adjustments reflect actual amounts recorded as of the Emergence Date. 21. Accounts Receivable. This adjustment relates to a change in accounting policy for the way the Company will present uncollected deferred revenue upon emergence from bankruptcy. The Company will offset such deferred revenue against the related account receivable. 22. Inventory . This adjustment relates to the write-up of inventory to fair value based on estimated selling prices, less costs of disposal. 23. Other Current Assets . This adjustment reflects the write-off of certain prepaid commissions, deferred installation costs and debt issuance costs that do not meet the definition of an asset upon emergence. 24. Property, Plant and Equipment . An adjustment of $116 million was recorded to increase the net book value of property, plant and equipment to its estimated fair value based on estimated current acquisition price, plus costs to make the property fully operational. The following table reflects the components of property, plant and equipment, net as of December 15, 2017 : (In millions) Buildings and improvements $ 82 Machinery and equipment 38 Rental equipment 85 Assets under construction 13 Internal use software 92 Total property, plant and equipment 310 Less: accumulated depreciation and amortization — Property, plant and equipment, net $ 310 25. Deferred Income Tax. T he adjustment represents the release of the valuation allowance on deferred tax assets for certain non-U.S. subsidiaries which management believes more likely than not will be realized as a result of future taxable income from the reversal of deferred tax liabilities that were established as part of fresh start accounting. 26. Intangible Assets. The Company recorded an adjustment to intangible assets for $3,137 million as follows: (In millions) Successor Predecessor December 15, 2017 Post-emergence December 15, 2017 Pre-emergence Difference Customer relationships and other intangible assets $ 2,155 $ 96 $ 2,059 Technology and patents 905 12 893 Trademarks and trade names 375 190 185 Total $ 3,435 $ 298 $ 3,137 The fair value of customer relationships was determined using the excess earnings method, a derivation of the income approach that calculates residual profit attributable to an asset after proper returns are paid to complementary or contributory assets. The fair value of technology and patents and trademarks and trade names determined using the royalty savings method, a derivation of the income approach that estimates the royalties saved through ownership of the assets. 27. Goodwill. Predecessor goodwill of $3,541 million was eliminated and Successor goodwill of $2,632 million was established based on the calculated reorganization value. (In millions) Reorganization value of Successor Company $ 7,583 Less: Fair value of Successor Company assets (4,951 ) Reorganization value of Successor Company assets in excess of fair value - goodwill $ 2,632 28. Other Assets. The $27 million decrease to other assets is related to prepaid commissions that do not meet the definition of an asset upon emergence as there is no future benefit to the Successor Company. 29. Deferred Revenue. The fair value of deferred revenue, which principally relates to payments on annual maintenance contracts, was determined by deducting selling costs and associated profit from the Predecessor deferred revenue balance to arrive at the costs and profit associated with fulfilling the liability. Additionally, the decrease includes the impact of an accounting policy change whereby the Successor Company no longer presents uncollected deferred revenue. 30. Other Current Liabilities. The decrease of $3 million to other current liabilities is related to the fair value of real estate leases determined to be above or below market using the income approach based on the difference between the contractual rental rate and the estimated market rental rate, discounted utilizing a risk-related discount rate. 31. Long-term Debt . The fair value of the Term Loan Credit Agreement was determined based on a market approach utilizing market-clearing data on the valuation date in addition to bid/ask prices. 32. Deferred Income Taxes. The adjustment represents the establishment of deferred tax liabilities related to book/tax differences created by fresh start accounting adjustments. The amount is net of the release of the valuation allowance on deferred tax assets, which management believes more likely than not will be realized as a result of future taxable income from the reversal of such deferred tax liabilities. 33. Business Restructuring Reserve. The Company recorded an increase to its non-current business restructuring reserves based on estimated future cash flows applied to a current discount rate at emergence. 34. Other Liabilities. A decrease in other liabilities of $43 million relates to deferred revenue and real estate leases as previously discussed. 35. Accumulated Other Comprehensive Loss. The remaining balance in Accumulated comprehensive loss was reversed to Reorganization expenses, net. 36. Fresh Start Adjustments. The following table reflects the cumulative impact of the fresh start adjustments as discussed above, the elimination of the Predecessor Company's accumulated other comprehensive loss and the adjustments required to eliminate accumulated deficit. (In millions) Eliminate Predecessor Intangible assets $ (298 ) Eliminate Predecessor Goodwill (3,541 ) Establish Successor Intangible assets 3,435 Establish Successor Goodwill 2,632 Fair value adjustment to Inventory 29 Fair value adjustment to Other current assets (66 ) Fair value adjustment to Property, plant and equipment 116 Fair value adjustment to Other assets (27 ) Fair value adjustment to Deferred revenue 235 Fair value adjustment to Business restructuring reserves (4 ) Fair value adjustment to Other current liabilities 3 Fair value adjustment to Long-term debt (96 ) Fair value adjustment to Other liabilities 43 Release Predecessor Accumulated comprehensive loss (790 ) Fresh start adjustments included in Reorganization items, net $ 1,671 Tax impact of fresh start adjustments (565 ) Gain on fresh start accounting $ 1,106

Fresh Start Accounting

Fresh Start Accounting	3 Months Ended
	Dec. 31, 2017
Reorganizations [Abstract]
Fresh Start Accounting	Emergence from Voluntary Reorganization under Chapter 11 Proceedings Plan of Reorganization On November 28, 2017 , the Bankruptcy Court entered an order confirming the Plan of Reorganization. On the Emergence Date, the Plan of Reorganization became effective and the Debtors emerged from bankruptcy. On or following the Emergence Date and pursuant to the terms of the Plan of Reorganization, the following occurred: • Debtor-in-Possession Credit Agreement. The Company paid in full the debtor-in-possession credit agreement (the "DIP Credit Agreement") in the amount of $725 million ; • Predecessor Equity and Indebtedness. The Debtors' obligations under stock certificates, equity interests, and / or any other instrument or document directly or indirectly evidencing or creating any indebtedness or obligation of, or ownership interest in, the Debtors or giving rise to any claim or equity interest were cancelled, except as provided under the Plan of Reorganization; • Successor Equity. The Company's certificate of incorporation was amended and restated to authorize the issuance of 605.0 million shares of Successor Company stock, consisting of 55.0 million shares of preferred stock, par value $0.01 per share, and 550.0 million shares of common stock, par value $0.01 per share, of which 110.0 million shares of common stock were issued (as discussed below); • Exit Financing. The Successor Company entered into (1) a term loan credit agreement ("the Term Loan Credit Agreement") for a principal amount of $2,925 million maturing on December 15, 2024 , and (2) a $300 million asset-based revolving credit facility (the "ABL Credit Agreement") maturing on December 15, 2022 ; • First Lien Debt Claims. All of the Predecessor Company's outstanding obligations under the variable rate term B-3, B-4, B-6, and B-7 loans and the 7% and 9% senior secured notes (collectively, the "Predecessor first lien obligations") were cancelled, and the holders of claims under the Predecessor first lien obligations received 99.3 million shares of Successor Company common stock. In addition, the holders of the Predecessor first lien obligations received cash in the amount of $2,061 million ; • Second Lien Debt Claims. All the Predecessor Company's outstanding obligations under the 10.50% senior secured notes (the "Predecessor second lien obligations") were cancelled, and the holders of claims under the Predecessor second lien obligations received 4.4 million shares of Successor Company common stock. In addition, holders of the Predecessor second lien obligations received warrants to purchase 5.6 million shares of Successor Company common stock at an exercise price of $25.55 per warrant (the "Warrants"); • Claims of Pension Benefit Guaranty Corporation ("PBGC"). The Predecessor Company's outstanding obligations under the Avaya Inc. Pension Plan for Salaried Employees ("APPSE") were terminated and transferred to the PBGC. The PBGC received 6.1 million shares of Successor Company common stock and $340 million in cash; and • General Unsecured Claims. Holders of the Predecessor Company's general unsecured claims will receive their pro rata share of the general unsecured recovery pool. A liquidating trust was established in the amount of $58 million for the benefit of the general unsecured claims. Included in the 110.0 million Successor Company common stock issued are 0.2 million additional shares of common stock that have been issued (but are not outstanding) for the benefit of the general unsecured creditors. The general unsecured creditors will receive a total of $58 million in cash and common stock. Any excess cash and / or common stock not distributed to the general unsecured creditors will be distributed to the holders of the Predecessor first lien obligations. Section 363 Asset Sales In July 2017, the Company sold its networking business ("Networking" or the "Networking business") to Extreme Networks, Inc. ("Extreme"). The Networking business was comprised primarily of certain assets of the Company's Networking segment (which prior to the sale was a separate operating segment), along with the maintenance and professional services of the Networking business, which were part of the AGS segment. Under a Transition Services Agreement ("TSA"), the Company provides administrative services to Extreme for process support, maintenance services and product logistics on a fee basis. While the TSA can expire sooner, the agreement terminates after 2 years . Fresh Start Accounting In connection with the Company's emergence from bankruptcy and in accordance with FASB Accounting Standards Codification ("ASC") 852, "Reorganizations" ("ASC 852"), the Company applied the provisions of fresh start accounting to its Condensed Consolidated Financial Statements on the Emergence Date. The Company was required to use fresh start accounting since (i) the holders of existing voting shares of the Predecessor Company received less than 50% of the voting shares of the emerging entity and (ii) the reorganization value of the Company's assets immediately prior to confirmation of the Plan of Reorganization was less than the post-petition liabilities and allowed claims. ASC 852 prescribes that with the application of fresh start accounting, the Company allocated its reorganization value to its individual assets based on their estimated fair values in conformity with ASC 805, "Business Combinations". The reorganization value represents the fair value of the Successor Company's assets before considering liabilities. The excess reorganization value over the fair value of identified tangible and intangible assets is reported as goodwill. As a result of the application of fresh start accounting and the effects of the implementation of the Plan of Reorganization, the consolidated financial statements after December 15, 2017 are not comparable with the consolidated financial statements as of or prior to that date. Reorganization Value As set forth in the Plan of Reorganization, the agreed upon enterprise value of the Company was $5,721 million . This value is within the initial range calculated by the Company of approximately $5,100 million to approximately $7,100 million using an income approach. The $5,721 million enterprise value was selected as it was the transaction price agreed to in the global settlement agreement with the Company’s creditor constituencies, including the PBGC. The reorganization value was then determined by adding back liabilities other than interest bearing debt, pension obligations and the deferred tax impact of the reorganization and fresh start adjustments. The following table reconciles the enterprise value to the estimated fair value of the Successor stockholders' equity as of the Emergence Date: (In millions, except per share amount) Enterprise value $ 5,721 Plus: Cash and cash equivalents 340 Less: Minimum cash required for operations (120 ) Fair value of Term Loan Credit Agreement (1) (2,896 ) Fair value of capitalized leases (20 ) Fair value of pension and other post-retirement obligations, net of tax (2) (856 ) Change in net deferred tax liabilities from reorganization (510 ) Fair value of Successor warrants (3) (17 ) Fair value of Successor common stock $ 1,642 Shares issued at December 15, 2017 110.0 Per share value $ 14.93 (1) The fair value of the Term Loan Credit Agreement was determined based on a market approach utilizing market-clearing data on the valuation date in addition to bid/ask prices and was estimated to be 99% of par value. (2) The following assumptions were used when measuring the fair value of the U.S. pension, non-U.S. pension, and post-retirement benefit plans: weighted-average return on assets of 7.75% , 3.80% and 5.90% , and weighted-average discount rate to measure plan obligations of 3.70% , 1.52% and 3.77% , respectively. (3) The fair value of the Warrants was estimated using the Black-Scholes pricing model. The following table reconciles the enterprise value to the estimated reorganization value as of the Emergence Date: (In millions) Enterprise value $ 5,721 Plus: Non-debt current liabilities 955 Non-debt non-current liabilities 2,090 Excess cash and cash equivalents 220 Less: Pension and other post-retirement obligations, net of deferred taxes (856 ) Capital lease obligations (20 ) Change in net deferred tax liabilities from reorganization (510 ) Warrants issued upon emergence (17 ) Reorganization value of Successor assets $ 7,583 Consolidated Balance Sheet The adjustments set forth in the following consolidated balance sheet as of December 15, 2017 reflect the effect of the consummation of the transactions contemplated by the Plan of Reorganization (reflected in the column "Reorganization Adjustments") as well as fair value adjustments as a result of applying fresh start accounting (reflected in the column "Fresh Start Adjustments"). The explanatory notes highlight methods used to determine fair values or other amounts of the assets and liabilities, as well as significant assumptions or inputs. (In millions) Predecessor Company Reorganization Adjustments Fresh Start Adjustments Successor Company December 15, 2017 ASSETS Current assets: Cash and cash equivalents $ 744 $ (404 ) (1) $ — $ 340 Accounts receivable, net 523 — (106 ) (21,29) 417 Inventory 98 — 29 (22) 127 Other current assets 366 (58 ) (2) (66 ) (23) 242 TOTAL CURRENT ASSETS 1,731 (462 ) (143 ) 1,126 Property, plant and equipment, net 194 — 116 (24) 310 Deferred income taxes, net — 48 (3) (17 ) (25) 31 Intangible assets, net 298 — 3,137 (26) 3,435 Goodwill 3,541 — (909 ) (27) 2,632 Other assets 70 6 (4) (27 ) (28) 49 TOTAL ASSETS $ 5,834 $ (408 ) $ 2,157 $ 7,583 LIABILITIES Current liabilities: Debt maturing within one year $ 725 $ (696 ) (5) $ — $ 29 Accounts payable 325 (49 ) (6) — 276 Payroll and benefit obligations 123 23 (7) — 146 Deferred revenue 627 50 (8) (341 ) (29) 336 Business restructuring reserve 35 3 (9) — 38 Other current liabilities 97 65 (6,10) (3 ) (30) 159 TOTAL CURRENT LIABILITIES 1,932 (604 ) (344 ) 984 Non-current liabilities: Long-term debt, net of current portion — 2,771 (11) 96 (31) 2,867 Pension obligations 539 246 (12) — 785 Other post-retirement obligations — 212 (13) — 212 Deferred income taxes, net 28 113 (14) 548 (32) 689 Business restructuring reserve 26 4 (9) 4 (33) 34 Other liabilities 180 233 (8,15) (43 ) (29,34) 370 TOTAL NON-CURRENT LIABILITIES 773 3,579 605 4,957 LIABILITIES SUBJECT TO COMPROMISE 7,585 (7,585 ) (16) — — TOTAL LIABILITIES 10,290 (4,610 ) 261 5,941 Commitments and contingencies Equity awards on redeemable shares 6 (6 ) (17) — — Preferred stock: Series B 397 (397 ) (17) — — Series A 186 (186 ) (17) — — STOCKHOLDERS' (DEFICIT) EQUITY Common stock (Successor) — 1 (18) — 1 Additional paid-in capital (Successor) — 1,641 (18) — 1,641 Common stock (Predecessor) — — — — Additional paid-in capital (Predecessor) 2,387 (2,387 ) (17) — — (Accumulated deficit) retained earnings (5,978 ) 4,872 (19) 1,106 (36) — Accumulated other comprehensive (loss) income (1,454 ) 664 (20) 790 (35) — TOTAL STOCKHOLDERS' (DEFICIT) EQUITY (5,045 ) 4,791 1,896 1,642 TOTAL LIABILITIES AND STOCKHOLDERS' (DEFICIT) EQUITY $ 5,834 $ (408 ) $ 2,157 $ 7,583 Reorganization Adjustments In accordance with the Plan of Reorganization, the following adjustments were made: 1. Sources and Uses of Cash. The following reflects the net cash payments recorded as of the Emergence Date as a result of implementing the Plan of Reorganization: (In millions) Sources: Proceeds from Term Loan Credit Agreement, net of original issue discount $ 2,896 Release of restricted cash 76 Total sources of cash 2,972 Uses: Repayment of DIP Credit Agreement (725 ) Payment of DIP accrued interest (1 ) Cash paid to Predecessor first lien debt-holders (2,061 ) Cash paid to PBGC (340 ) Payment for professional fees escrow account (56 ) Funding payment for Avaya represented employee pension plan (49 ) Payment of accrued professional & administrative fees (27 ) Costs incurred for Term Loan Credit Agreement and ABL Credit Agreement (59 ) Payment for general unsecured claims (58 ) Total uses of cash (3,376 ) Net uses of cash $ (404 ) 2. Other Current Assets. (In millions) Release of restricted cash $ (76 ) Reclassification of prepaid debt issuance costs related to the Term Loan Credit Agreement (42 ) Payment of fees related to the ABL Credit Agreement 5 Restricted cash for bankruptcy related professional fees 55 Total other current assets $ (58 ) 3. Deferred Income Taxes. The adjustment represents the release of the valuation allowance on deferred tax assets for certain non-U.S. subsidiaries which management believes more likely than not will be realized as a result of the bankruptcy reorganization. 4. Other Assets. The adjustment represents the re-establishment of a foreign prepaid tax. 5. Debt Maturing Within One Year. The adjustment represents the net effect of the Company’s repayment of $725 million for the DIP Credit Agreement and Term Loan Credit Agreement principal payments of $29 million due over the next year. 6. Accounts Payable . The net decrease of $49 million includes $50 million for professional fees that were reclassified to Other current liabilities for accrued bankruptcy related professional fees that will be paid from an escrow account and the payment of $3 million of bankruptcy related professional fees, partially offset by reinstatement of $4 million contact cure costs from liabilities subject to compromise. 7. Payroll and Benefi t Obligations. The Company reinstated $23 million of liabilities subject to compromise related to the post-employment and post-retirement benefit obligations. 8. Deferred Revenue. The reinstatement of liabilities subject to compromise was $79 million of which $50 million is included in deferred revenue and $29 million in other liabilities. 9. Business Restructuring Reserve. The reinstatement of liabilities subject to compromise was $7 million , of which $3 million is current and $4 million is non-current. 10. Other Current Liabilities. (In millions) Reclassification of accrued bankruptcy related professional fees $ 50 Reinstatement of other current liabilities 16 Payment of accrued interest on the DIP Credit Agreement (1 ) Total other current liabilities $ 65 11. Exit Financing. In accordance with the Plan of Reorganization, the Company entered into the Term Loan Credit Agreement with a principal amount of $2,925 million maturing seven years from the date of issuance, and the ABL Credit Agreement, which allows borrowings up to an aggregate principal amount of $300 million , subject to borrowing base availability, maturing five years from the date of issuance. (In millions) Term Loan Credit Agreement $ 2,925 Less: Discount (29 ) Upfront and underwriting fees (54 ) Cash received upon emergence from bankruptcy 2,842 Reclassification of debt issuance cost incurred prior to emergence from bankruptcy (42 ) Current portion of Long-term debt (29 ) Long-term debt, net of current portion $ 2,771 12. Pension Obligations. In accordance with the Plan of Reorganization, the Company reinstated from liabilities subject to compromise $295 million related to the Avaya Pension Plan for represented employees and also contributed $49 million to the related pension trust. 13. Other Post-retirement Obligations. Other post-retirement benefit obligations of $212 million were reinstated from liabilities subject to compromise. 14. Deferred Income Taxes . The adjustment represents the reinstatement of the deferred tax liability that was included in liabilities subject to compromise. 15. Other Liabilities . The increase of $233 million primarily relates to the reinstatement of employee benefits, tax liabilities and deferred revenue from liabilities subject to compromise. Also included is the value of the Warrants issued to the holders of the Predecessor second lien obligations on the Emergence Date. 16. Liabilities Subject to Compromise. Liabilities subject to compromise were reinstated or settled as follows in accordance with the Plan of Reorganization: (In millions) Liabilities subject to compromise $ 7,585 Less amounts settled per the Plan of Reorganization Pre-petition first lien debt (4,281 ) Pre-petition second lien debt (1,440 ) Avaya Pension Plan for Salaried Employees (620 ) Amounts reinstated: Accounts payable (4 ) Payroll and benefit obligations (23 ) Deferred revenue (50 ) Business restructuring reserves (7 ) Other current liabilities (16 ) Pension obligations (295 ) Other post-retirement obligations (212 ) Deferred income taxes, net (118 ) Other liabilities (216 ) Total liabilities reinstated at emergence (941 ) General unsecured credit claims (1) (303 ) Liabilities subject to compromise $ — (1) In settlement of allowed general unsecured claims, each claimant will receive a pro-rata distribution of $58 million of the general unsecured claims account. The following table displays the detail on the gain on settlement of liabilities subject to compromise: (In millions) Pre-petition first lien debt $ 734 Pre-petition second lien debt 1,357 Avaya pension plan for salaried employees (514 ) General unsecured creditors' claims 227 Net gain on settlement of Liabilities subject to compromise $ 1,804 17. Cancellation of Predecessor Preferred and Common Stock. All common stock, Series A and B preferred stock and all other equity awards of the Predecessor Company were cancelled on the Emergence Date without any recovery on account thereof. 18. Issuance of Successor Common Stock and Warrants. In settlement of the Company's $5,721 million Predecessor first lien obligations and Predecessor second lien obligations, the holders of the Predecessor first lien obligations received a total of 99.3 million shares of common stock (fair value of $1,486 million ) and $2,061 million in cash and the holders of the Predecessor second lien obligations received a total of 4.4 million shares of common stock (fair value of $66 million ) and 5.6 million of Warrants to purchase additional common shares (fair value of $17 million ). In addition, as part of the Plan of Reorganization, the Company completed a distressed termination of the APPSE in accordance with the Stipulation Settlement with the PBGC, the PBGC received $340 million in cash and 6.1 million shares of common stock (fair value of $90 million ). 19. Accumulated Deficit. (In millions) Accumulated deficit: Net gain on settlement of liabilities subject to compromise $ 1,804 Expense for certain professional fees (26 ) Benefit from income taxes 118 Cancellation of Predecessor equity awards 6 Cancellation of Predecessor Preferred stock Series B 397 Cancellation of Predecessor Preferred stock Series A 186 Cancellation of Predecessor Common stock 2,387 Total $ 4,872 20. Accumulated Comprehensive Loss. The changes to Accumulated comprehensive loss relate to the settlement of the APPSE and the Avaya Supplemental Pension Plan ("ASPP") and the associated taxes. Fresh Start Adjustments At the Emergence Date, the Company met the requirements under ASC 852 for fresh start accounting as (i) the holders of existing voting shares of the Predecessor Company received less than 50% of the voting shares of the emerging entity and (ii) the reorganization value of the Company's assets immediately prior to confirmation was less than the post-petition liabilities and allowed claims. These adjustments reflect actual amounts recorded as of the Emergence Date. 21. Accounts Receivable. This adjustment relates to a change in accounting policy for the way the Company will present uncollected deferred revenue upon emergence from bankruptcy. The Company will offset such deferred revenue against the related account receivable. 22. Inventory . This adjustment relates to the write-up of inventory to fair value based on estimated selling prices, less costs of disposal. 23. Other Current Assets . This adjustment reflects the write-off of certain prepaid commissions, deferred installation costs and debt issuance costs that do not meet the definition of an asset upon emergence. 24. Property, Plant and Equipment . An adjustment of $116 million was recorded to increase the net book value of property, plant and equipment to its estimated fair value based on estimated current acquisition price, plus costs to make the property fully operational. The following table reflects the components of property, plant and equipment, net as of December 15, 2017 : (In millions) Buildings and improvements $ 82 Machinery and equipment 38 Rental equipment 85 Assets under construction 13 Internal use software 92 Total property, plant and equipment 310 Less: accumulated depreciation and amortization — Property, plant and equipment, net $ 310 25. Deferred Income Tax. T he adjustment represents the release of the valuation allowance on deferred tax assets for certain non-U.S. subsidiaries which management believes more likely than not will be realized as a result of future taxable income from the reversal of deferred tax liabilities that were established as part of fresh start accounting. 26. Intangible Assets. The Company recorded an adjustment to intangible assets for $3,137 million as follows: (In millions) Successor Predecessor December 15, 2017 Post-emergence December 15, 2017 Pre-emergence Difference Customer relationships and other intangible assets $ 2,155 $ 96 $ 2,059 Technology and patents 905 12 893 Trademarks and trade names 375 190 185 Total $ 3,435 $ 298 $ 3,137 The fair value of customer relationships was determined using the excess earnings method, a derivation of the income approach that calculates residual profit attributable to an asset after proper returns are paid to complementary or contributory assets. The fair value of technology and patents and trademarks and trade names determined using the royalty savings method, a derivation of the income approach that estimates the royalties saved through ownership of the assets. 27. Goodwill. Predecessor goodwill of $3,541 million was eliminated and Successor goodwill of $2,632 million was established based on the calculated reorganization value. (In millions) Reorganization value of Successor Company $ 7,583 Less: Fair value of Successor Company assets (4,951 ) Reorganization value of Successor Company assets in excess of fair value - goodwill $ 2,632 28. Other Assets. The $27 million decrease to other assets is related to prepaid commissions that do not meet the definition of an asset upon emergence as there is no future benefit to the Successor Company. 29. Deferred Revenue. The fair value of deferred revenue, which principally relates to payments on annual maintenance contracts, was determined by deducting selling costs and associated profit from the Predecessor deferred revenue balance to arrive at the costs and profit associated with fulfilling the liability. Additionally, the decrease includes the impact of an accounting policy change whereby the Successor Company no longer presents uncollected deferred revenue. 30. Other Current Liabilities. The decrease of $3 million to other current liabilities is related to the fair value of real estate leases determined to be above or below market using the income approach based on the difference between the contractual rental rate and the estimated market rental rate, discounted utilizing a risk-related discount rate. 31. Long-term Debt . The fair value of the Term Loan Credit Agreement was determined based on a market approach utilizing market-clearing data on the valuation date in addition to bid/ask prices. 32. Deferred Income Taxes. The adjustment represents the establishment of deferred tax liabilities related to book/tax differences created by fresh start accounting adjustments. The amount is net of the release of the valuation allowance on deferred tax assets, which management believes more likely than not will be realized as a result of future taxable income from the reversal of such deferred tax liabilities. 33. Business Restructuring Reserve. The Company recorded an increase to its non-current business restructuring reserves based on estimated future cash flows applied to a current discount rate at emergence. 34. Other Liabilities. A decrease in other liabilities of $43 million relates to deferred revenue and real estate leases as previously discussed. 35. Accumulated Other Comprehensive Loss. The remaining balance in Accumulated comprehensive loss was reversed to Reorganization expenses, net. 36. Fresh Start Adjustments. The following table reflects the cumulative impact of the fresh start adjustments as discussed above, the elimination of the Predecessor Company's accumulated other comprehensive loss and the adjustments required to eliminate accumulated deficit. (In millions) Eliminate Predecessor Intangible assets $ (298 ) Eliminate Predecessor Goodwill (3,541 ) Establish Successor Intangible assets 3,435 Establish Successor Goodwill 2,632 Fair value adjustment to Inventory 29 Fair value adjustment to Other current assets (66 ) Fair value adjustment to Property, plant and equipment 116 Fair value adjustment to Other assets (27 ) Fair value adjustment to Deferred revenue 235 Fair value adjustment to Business restructuring reserves (4 ) Fair value adjustment to Other current liabilities 3 Fair value adjustment to Long-term debt (96 ) Fair value adjustment to Other liabilities 43 Release Predecessor Accumulated comprehensive loss (790 ) Fresh start adjustments included in Reorganization items, net $ 1,671 Tax impact of fresh start adjustments (565 ) Gain on fresh start accounting $ 1,106

Goodwill And Intangible Assets

Goodwill And Intangible Assets	3 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill Goodwill is not amortized but is subject to periodic testing for impairment in accordance with GAAP at the reporting unit level, which is one level below the Company’s operating segments. The Company performs impairment testing annually or more frequently if events occur or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Company determined that no events occurred or circumstances changed during the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor) that would more likely than not reduce the fair value of any of the Company's reporting units below their respective carrying amounts. However, if conditions deteriorate or there is a change in the business, it may be necessary to record impairment charges in the future. The Company adjusted the carrying value of goodwill upon application of fresh start accounting. The carrying value of goodwill by operating segments for the periods indicated was as follows: (In millions) Global Communications Solutions Avaya Global Services Total September 30, 2017 (Predecessor) $ 1,093 $ 2,449 $ 3,542 Adjustments (1 ) — (1 ) Impact of fresh start accounting 68 (977 ) (909 ) December 15, 2017 (Predecessor) $ 1,160 $ 1,472 $ 2,632 December 31, 2017 (Successor) $ 1,160 $ 1,472 $ 2,632 Intangible Assets Intangible assets include technology, customer relationships, trademarks and trade-names and other intangibles. Intangible assets with finite lives are amortized using the straight-line method over the estimated economic lives of the assets, which range from three years to twenty years . Long-lived assets, including intangible assets with finite lives, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Intangible assets determined to have indefinite useful lives are not amortized. The Company performs impairment testing annually or more frequently if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. The Avaya trade name is expected to generate cash flow indefinitely. Consequently, this asset is classified as an indefinite-lived intangible. The Company determined that no events had occurred or circumstances changed during the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor) that would indicate that its long-lived assets, including intangible assets with finite lives, may not be recoverable or that it is more likely than not that its intangible assets with indefinite lives are impaired. However, if conditions deteriorate or there is a change in the business, it may be necessary to record impairment charges in the future. The Company adjusted the carrying value of intangible assets upon application of fresh start accounting. The gross carrying amount and accumulated amortization by major intangible asset category as of December 31, 2017 (Successor) and September 30, 2017 (Predecessor) were as follows: Successor As of December 31, 2017 (In millions) Technology and patents Customer relationships and other intangibles Trademarks Total Gross Carrying Amount $ 905 $ 2,155 $ 375 $ 3,435 Accumulated Amortization (7 ) (7 ) — (14 ) Net $ 898 $ 2,148 $ 375 $ 3,421 Predecessor As of September 30, 2017 (In millions) Technology and patents Customer relationships and other intangibles Trademarks Total Gross Carrying Amount $ 1,427 $ 2,196 $ 545 $ 4,168 Accumulated Amortization (1,411 ) (2,091 ) — (3,502 ) Accumulated Impairment — — (355 ) (355 ) Net $ 16 $ 105 $ 190 $ 311 Amortization expense related to intangible assets was $14 million , $13 million and $62 million for the period from December 16, 2017 through December 31, 2017 (Successor), the period from October 1, 2017 through December 15, 2017 (Predecessor) and the three months ended December 31, 2016 (Predecessor), respectively. The technology and patents have useful lives that range between 3 years and 10 years with a weighted average remaining useful life of 5.7 years . Customer relationships have useful lives that range between 7 years and 20 years with a weighted average useful life of 14.5 years . Amortizable product trade names have useful lives of 10 years . The Avaya trade name is expected to generate cash flows indefinitely and, consequently, this asset is classified as an indefinite-lived intangible. Future amortization expense related to intangible assets as of December 31, 2017 are as follows: (In millions) Remainder of fiscal 2018 $ 247 2019 326 2020 326 2021 325 2022 298 2023 and thereafter 1,566 Total $ 3,088

Supplementary Financial Informa

Supplementary Financial Information	3 Months Ended
	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Supplementary Financial Information	Supplementary Financial Information Supplemental Operations Information A summary of other (expense) income, net for the periods indicated is presented in the following table: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 OTHER (EXPENSE) INCOME, NET Interest income $ — $ 2 $ — Foreign currency gains, net 2 — 11 Income from transition services agreement, net — 3 — Other pension and post-retirement benefit costs 1 (8 ) (6 ) Change in fair value of the warrant liability (5 ) — — Other, net — 1 (1 ) Total other (expense) income, net $ (2 ) $ (2 ) $ 4 A summary of reorganization items, net for the periods indicated is presented in the following table: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 REORGANIZATION ITEMS, NET Bankruptcy-related professional fees $ — $ (56 ) $ — Net gain on settlement of liabilities subject to compromise — 1,804 — Net gain on fresh start adjustments — 1,671 — Other items, net — (3 ) — Reorganization items, net $ — $ 3,416 $ — Cash payments for reorganization items $ 1 $ 2,524 $ — Costs directly attributable to the implementation of the Plan of Reorganization were reported as reorganization items, net. The cash payments for reorganization items for the period from October 1, 2017 through December 15, 2017 (Predecessor) included $2,468 million of claims paid related to liabilities subject to compromise and $56 million for bankruptcy-related professional fees, including emergence and success fees paid on the Emergence Date.

Business Restructuring Reserves

Business Restructuring Reserves And Programs	3 Months Ended
	Dec. 31, 2017
Restructuring Reserve [Abstract]
Business Restructuring Reserves and Programs	Business Restructuring Reserves and Programs For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company recognized restructuring charges of $10 million and $14 million , respectively, including adjustments to the restructuring programs of prior fiscal years primarily consisting of the termination/buyout of leases. As the Company continues to evaluate opportunities to streamline its operations, it may identify cost savings globally and take additional restructuring actions in the future and the costs of those actions could be material. Fiscal 2018 Restructuring Program During the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), recognized restructuring charges for the fiscal 2018 restructuring program were for employee separation costs associated with employee severance actions primarily in the U.S. and Europe, Middle East and Africa ("EMEA"), primarily the U.K. and for which the related payments are expected to be completed by the beginning of fiscal 2020 . These actions include workforce reductions of 206 employees including 120 in the U.S. and 25 in EMEA. The separation charges include, but are not limited to, pension fund payments and health care and unemployment insurance costs to be paid to or on behalf of the affected employees. The following table summarizes the components of the fiscal 2018 restructuring program for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor): (In millions) Employee Separation Costs Lease Obligations Total 2018 restructuring charges $ 12 $ — $ 12 Cash payments (3 ) — (3 ) Balance as of December 15, 2017 (Predecessor) $ 9 $ — $ 9 2018 restructuring charges (1) $ — $ 10 $ 10 Cash payments (2 ) (10 ) (12 ) Balance as of December 31, 2017 (Successor) $ 7 $ — $ 7 (1) Charges incurred in connection with the termination of the Santa Clara lease. Fiscal 2017 Restructuring Program During fiscal 2017 , the Company identified opportunities to streamline operations and generate costs savings, which included eliminating employee positions. These obligations are primarily for employee separation costs associated with fiscal 2017 employee severance actions in the U.S. and EMEA, for which the related payments are expected to be completed in fiscal 2023 . The separation charges include, but are not limited to, pension fund payments and health care and unemployment insurance costs to be paid to or on behalf of the affected employees. The following table summarizes the components of the fiscal 2017 restructuring program for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor): (In millions) Employee Separation Costs Lease Obligations Total Balance as of September 30, 2017 (Predecessor) $ 4 $ 1 $ 5 Cash payments (1 ) (1 ) (2 ) Balance as of December 15, 2017 (Predecessor) $ 3 $ — $ 3 Balance as of December 31, 2017 (Successor) $ 3 $ — $ 3 Fiscal 2008 through 2016 Restructuring Programs During fiscal years 2008 through 2016 , the Company identified opportunities to streamline operations and generate cost savings, which included eliminating employee positions and exiting facilities. The remaining obligations related to these restructuring programs are for employee severance costs are primarily associated with EMEA plans expected to be completed by fiscal 2023 . The following table aggregates the components of the fiscal 2008 through 2016 restructuring programs for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor): (In millions) Employee Separation Costs Lease Obligations Total Balance as of September 30, 2017 (Predecessor) $ 51 $ 24 $ 75 Cash payments (3 ) (17 ) (20 ) Expense 1 1 2 Adjustments - fresh start and reorganization items $ 4 $ (1 ) $ 3 Balance as of December 15, 2017 (Predecessor) $ 53 $ 7 $ 60 Cash Payments (2 ) — (2 ) Impact of foreign currency fluctuations 2 — 2 Balance as of December 31, 2017 (Successor) $ 53 $ 7 $ 60

Financing Arrangements

Financing Arrangements	3 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Financing Arrangements	Financing Arrangements The following table reflects principal amounts of debt and debt net of discounts and issuance costs as of December 31, 2017 (Successor) and principal amounts of debt and debt net of discounts and issuance costs as of September 30, 2017 (Predecessor) , which includes the impact of adequate protection payments and accrued interest as of January 19, 2017: Successor Predecessor December 31, 2017 September 30, 2017 (In millions) Principal amount Net of discounts and issuance costs Principal amount Net of discounts and issuance costs Term Loan Credit Agreement $ 2,925 $ 2,896 $ — $ — DIP Credit Agreement due January 19, 2018 — — 725 725 First lien debt: Senior secured term B-3 loans — — 594 594 Senior secured term B-4 loans — — 1 1 Senior secured term B-6 loans — — 519 519 Senior secured term B-7 loans — — 2,012 2,012 7% senior secured notes — — 982 982 9% senior secured notes — — 284 284 Second lien debt: 10.50% senior secured notes — — 1,440 1,440 Total debt $ 2,925 2,896 $ 6,557 6,557 Debt maturing within one year (29 ) (725 ) Long-term debt, net of current portion (1) $ 2,867 $ 5,832 (1) Pre-petition long-term debt as of September 30, 2017 (Predecessor) was included in liabilities subject to compromise. On the Emergence Date: 1. the Successor Company entered into the Term Loan Credit Agreement and the ABL Credit Agreement; 2. the DIP Credit Agreement was paid in full; 3. the holders of the Predecessor first lien obligations received cash and Successor Company common stock (aggregate fair value of $3,547 million ) and the Company cancelled $4,281 million of the Predecessor Company first lien obligations; and 4. the holders of the Predecessor second lien obligations received Successor Company common stock and Warrants to purchase common stock (aggregate fair value of $83 million ) and the Company cancelled $1,440 million of the Predecessor Company second lien obligations. Successor Financing On the Emergence Date, Avaya Inc. entered into (i) the Term Loan Credit Agreement among Avaya Inc., as borrower, Avaya Holdings, the lending institutions from time to time party thereto, and Goldman Sachs Bank USA, as administrative agent and collateral agent, which provided a $2,925 million term loan facility maturing on December 15, 2024 and (ii) the ABL Credit Agreement maturing on December 15, 2022 , among Avaya Inc., as borrower, Avaya Holdings, the several other borrowers party thereto, the several lenders from time to time party thereto, and Citibank, N.A., as administrative agent and collateral agent, which provided a revolving credit facility consisting of a U.S. tranche and a foreign tranche allowing for borrowings of up to an aggregate principal amount of $300 million from time to time, subject to borrowing base availability (the ABL Credit Agreement together with the Term Loan Credit Agreement, the “Credit Agreements”). The Term Loan Credit Agreement, in the case of ABR Loans, bears interest at a rate per annum equal to 3.75% plus the highest of (i) the Federal Funds Rate plus 0.50% , (ii) the U.S. prime rate as publicly announced in the Wall Street Journal and (iii) the LIBOR Rate for an interest period of one month and in the case of LIBOR Loans, bears interest at a rate per annum equal to 4.75% plus the applicable LIBOR Rate, subject to a 1% floor. The ABL Credit Agreement bears interest: 1. In the case of Base Rate Loans denominated in U.S. dollars, at a rate per annum equal to 0.75% (subject to a 0.25% step-up or step-down based on availability) plus the highest of (i) the Federal Funds Rate plus 0.50% , (ii) the U.S. prime rate as publicly announced by Citibank, N.A. and (iii) the LIBOR Rate for an interest period of one month; 2. In the case of LIBOR Rate Loans denominated in U.S. dollars, at a rate per annum equal to 1.75% (subject to a 0.25% step-up or step-down based on availability) plus the applicable LIBOR Rate; 3. In the case of Canadian Prime Rate Loans denominated in Canadian dollars, at a rate per annum equal to 0.75% (subject to a 0.25% step-up or step-down based on availability) plus the highest of (i) the “Base Rate” as publicly announced by Citibank, N.A., Canadian branch and (ii) the CDOR Rate for an interest period of 30 days; 4. In the case of CDOR Rate Loans denominated in Canadian dollars, at a rate per annum equal to 1.75% (subject to a 0.25% step-up or step-down based on availability) plus the applicable CDOR Rate; 5. In the case of LIBOR Rate Loans denominated in Sterling, at a rate per annum equal to 1.75% (subject to a 0.25% step-up or step-down based on availability) plus the applicable LIBOR Rate; 6. In the case of EURIBOR Rate Loans denominated in Euro, at a rate per annum equal to 1.75% (subject to a 0.25% step-up or step-down based on availability) plus the applicable LIBOR Rate; and 7. In the case of Overnight LIBOR Rate Loans, at a rate per annum equal to 1.75% (subject to a 0.25% step-up or step-down based on availability) plus the applicable Overnight LIBOR Rate. The Credit Agreements limit, among other things, Avaya Inc.’s ability to (i) incur indebtedness, (ii) incur liens, (iii) dispose of assets, (iv) make investments, (v) make dividends, or conduct redemptions and repurchases of capital stock, (vi) prepay junior indebtedness or amend junior indebtedness documents, (vii) enter into restricted agreements, (viii) enter into transactions with affiliates and (ix) modify the terms of any of its organizational documents. The Term Loan Credit Agreement does not contain any financial covenants. The ABL Credit Agreement does not contain any financial covenants other than a requirement to maintain a minimum fixed charge coverage ratio of 1 :1 that becomes applicable only in the event that the net borrowing availability under the ABL Credit Agreement is less than the greater of $25 million and 10% of the lesser of the total borrowing base and the ABL commitments (commonly known as the "line cap"). As of December 31, 2017 , the Company was not in default under any of its debt agreements. Under the terms of the ABL Credit Agreement, the Company can issue letters of credit up to $150 million . At December 31, 2017 , the Company had issued and outstanding letters of credit and guarantees of $74 million . The aggregate additional principal amount that may be borrowed under the ABL Credit Agreement, based on the borrowing base less $74 million of outstanding letters of credit and guarantees, was $139 million at December 31, 2017 . The weighted average contractual interest rate of the Company’s outstanding debt as of December 31, 2017 was 6.2% . Predecessor Financing Debt Covenants and Default. The indentures governing the Predecessor senior secured notes contained a number of covenants that, among other things and subject to certain exceptions, restricted the ability of the Predecessor and certain of its subsidiaries to (a) incur or guarantee additional debt and issue or sell certain preferred stock, (b) pay dividends on, redeem or repurchase capital stock, (c) make certain acquisitions or investments, (d) incur or assume certain liens, (e) enter into transactions with affiliates, (f) merge or consolidate with another company, (g) transfer or otherwise dispose of assets, (h) redeem subordinated debt, (i) incur obligations that restricted the ability of the Company’s subsidiaries to pay dividends or make other payments to the Company, and (j) create or designate unrestricted subsidiaries. They also contained customary affirmative covenants and events of default. The Bankruptcy Filing constituted an event of default that accelerated the Predecessor’s payment obligations under the senior secured credit agreements and the senior secured notes. As a result of the Bankruptcy Filing, the principal and interest due under the Predecessor’s debt agreements became due and payable. However, any efforts to enforce such payment obligations were automatically stayed as a result of the Bankruptcy Filing, and the creditors’ rights of enforcement were subject to the applicable provisions of the Bankruptcy Code and orders of the Bankruptcy Court. Consequently, all debt outstanding was classified as liabilities subject to compromise and all unamortized debt issuance costs and unaccreted debt discounts were expensed. DIP Credit Agreement. In connection with the Bankruptcy Filing, on the Petition Date, the Predecessor entered into the DIP Credit Agreement, which provided a $725 million term loan facility due January 2018, and a cash collateralized letter of credit facility in an aggregate amount equal to $150 million . All letters of credit were cash collateralized in an amount equal to 101.5% of the face amount of such letters of credit denominated in U.S. dollars and 103% of the face amount of letters of credit denominated in alternative currencies. The DIP Credit Agreement, in the case of the Base Rate Loans, bore interest at a rate per annum equal to 6.5% plus the highest of (i) Citibank, N.A.’s prime rate, (ii) the Federal Funds Rate plus 0.5% and (iii) the Eurocurrency Rate for an interest period of one month, subject to a 2% floor, and in the case of the Eurocurrency Loans, bore interest at a rate per annum equal to 7.5% plus the applicable Eurocurrency Rate, subject to a 1% floor. Capital Lease Obligations Included in other liabilities is $22 million and $14 million of capital lease obligations, net of imputed interest as of December 31, 2017 (Successor) and September 30, 2017 (Predecessor), respectively, and excluded amounts included in liabilities subject to compromise of $12 million as of September 30, 2017. The Company entered into an agreement to outsource certain delivery services associated with the Avaya Private Cloud Services business. That agreement also included the sale of specified assets owned by the Company, which are being leased-back by the Company and accounted for as a capital lease. As of December 31, 2017 (Successor) and September 30, 2017 (Predecessor), capital lease obligations associated with this agreement were $21 million and $24 million , respectively, and include $10 million within liabilities subject to compromise as of September 30, 2017.

Derivative Warrant Liability

Derivative Warrant Liability	3 Months Ended
	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Warrants	Derivative Warrant Liability In accordance with the Plan of Reorganization, on the Emergence Date the Company issued Warrants to purchase 5,645,200 shares of Successor common stock to the holders of the Predecessor second lien obligations pursuant to a warrant agreement (“Warrant Agreement”). Each Warrant has an exercise price of $25.55 per share and expires five years from the date of issuance. We account for derivative financial instruments in accordance with FASB ASC 815, "Derivatives and Hedging." The Warrants contain certain derivative features that require the Warrants to be classified as a liability and for changes in fair value of the liability to be recognized in earnings each reporting period. The Successor Company had no other derivative instruments at December 31, 2017 . The fair value of the Warrants was determined using a probability weighted Black-Scholes option pricing model. This model requires certain input assumptions including risk-free interest rates, volatility, expected life and dividend rates. Selection of these inputs involves significant judgment. The fair value of the Warrants, on the Emergence Date and at December 31, 2017 , was determined by using the Black-Scholes option pricing model with the input assumptions summarized below. Accordingly, we recorded a loss of $5 million for the period from December 16, 2017 through December 31, 2017 (Successor) related to the change in fair value of the warrant liability . The fair value loss was recognized in Other (expense) income, net in the Condensed Consolidated Statements of Operations. December 31, 2017 December 15, 2017 Expected volatility 52.38 % 54.57 % Risk free interest rates 2.20 % 2.20 % Expected life (in years) 4.96 5.00 Price per share of common stock $17.55 $14.93 Fair value of warrant liability $22 million $17 million

Fair Value Measures

Fair Value Measures	3 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measures	Fair Value Measures Pursuant to the accounting guidance for fair value measurements, fair value is the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and it considers assumptions that market participants would use when pricing the asset or liability. Fair Value Hierarchy The accounting guidance for fair value measurements also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The inputs are prioritized into three levels that may be used to measure fair value: Level 1: Inputs that reflect quoted prices for identical assets or liabilities in active markets that are observable. Level 2: Inputs that reflect quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; or model-derived valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data. Level 3: Inputs that are unobservable to the extent that observable inputs are not available for the asset or liability at the measurement date. Asset and Liabilities Measured at Fair Value on a Recurring Basis Assets and liabilities measured at fair value on a recurring basis as of December 31, 2017 (Successor) and September 30, 2017 (Predecessor) were as follows: Successor December 31, 2017 Fair Value Measurements Using (In millions) Total Level 1 Level 2 Level 3 Other Non-Current Assets: Investments $ 1 $ 1 $ — $ — Other Non-Current Liabilities: Warrants $ 22 $ — $ — $ 22 Predecessor September 30, 2017 Fair Value Measurements Using (In millions) Total Level 1 Level 2 Level 3 Other Non-Current Assets: Investments $ 1 $ 1 $ — $ — Investments Investments classified as Level 1 assets are priced using quoted market prices for identical assets in active markets that are observable. Warrants Warrants classified as Level 3 liabilities are priced using the Black-Scholes option pricing model. The change in fair value of the Warrants is recognized in Other (expense) income, net in the Condensed Consolidated Statements of Operations. Fair Value of Financial Instruments The estimated fair values of amounts borrowed under the Company’s financing arrangements at December 31, 2017 (Successor) and September 30, 2017 (Predecessor) were estimated based on a Level 2 input based on a market approach utilizing market-clearing data on the valuation date in addition to bid/ask prices. The estimated fair values of the amounts borrowed under the Company’s financing agreements at December 31, 2017 (Successor) and September 30, 2017 (Predecessor) are as follows: Successor Predecessor December 31, 2017 September 30, 2017 (In millions) Principal Amount Fair Value Principal Amount Fair Value Term Loan Credit Agreement due December 15, 2024 $ 2,925 $ 2,896 $ — $ — DIP Credit Agreement due January 19, 2018 — — 725 732 Variable rate Term B-3 Loans due October 26, 2017 — — 594 503 Variable rate Term B-4 Loans due October 26, 2017 — — 1 1 Variable rate Term B-6 Loans due March 31, 2018 — — 519 440 Variable rate Term B-7 Loans due May 29, 2020 — — 2,012 1,709 7% senior secured notes due April 1, 2019 — — 982 832 9% senior secured notes due April 1, 2019 — — 284 241 10.50% senior secured notes due March 1, 2021 — — 1,440 67 Total $ 2,925 $ 2,896 $ 6,557 $ 4,525 The Company adjusted the carrying value of debt to fair value upon application of fresh start accounting.

Income Taxes

Income Taxes	3 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the Predecessor period ended December 15, 2017, the difference between the Company’s recorded provision and the provision that would result from applying the U.S. statutory rate of 35% is primarily attributable to: (1) income and losses taxed at different foreign tax rates, (2) losses generated within certain foreign jurisdictions for which no benefit was recorded because it is more likely than not that the tax benefits would not be realized, (3) non-U.S. withholding taxes on foreign earnings, (4) current period changes to unrecognized tax positions, (5) U.S. state and local income taxes, and (6) the impact of reorganization and fresh start adjustments. For the Successor period ended December 31, 2017, the difference between the Company’s recorded benefit and the benefit that would result from applying the new U.S. statutory rate of 24.5%, is primarily attributable to: (1) income and losses taxed at different foreign tax rates, (2) losses generated within certain foreign jurisdictions for which no benefit was recorded because it is more likely than not that the tax benefits would not be realized, (3) non-U.S. withholding taxes on foreign earnings, (4) current period changes to unrecognized tax positions, (5) U.S. state and local income taxes, and (6) the impact of the Tax Cuts and Jobs Act (“the Act”), as more fully described below. For the three months ended December 31, 2016, the difference between the Company’s recorded provision and the benefit that would result from applying the U.S. statutory rate of 35% is primarily attributable to: (1) income and losses taxed at different foreign tax rates, (2) changes in the valuation allowance established against the Company’s deferred tax assets, and (3) current period changes to unrecognized tax positions. Under the Plan of Reorganization a substantial amount of the Company’s debt was extinguished. Absent an exception, a debtor recognizes cancellation of indebtedness income (“CODI”) upon discharge of its outstanding indebtedness for an amount of consideration that is less than its adjusted issue price. The Internal Revenue Code of 1986, as amended, provides that a debtor in a bankruptcy case may exclude CODI from taxable income but must reduce certain of its tax attributes by the amount of any CODI recognized as a result of the consummation of a plan of reorganization. The amount of CODI recognized by a taxpayer is the adjusted issue price of any indebtedness discharged less the sum of (i) the amount of cash paid, (ii) the issue price of any new indebtedness issued and (iii) the fair market value of any other consideration, including equity, issued. The reduction in tax attributes does not occur until the first day of the Company’s first tax year subsequent to the date of emergence, which is October 1, 2018. The Company estimates that the U.S. federal net operating loss (“NOL”) and tax credits disclosed in its September 30, 2017 Condensed Consolidated Financial Statements and the tax loss generated during the September 30, 2018 tax year will be entirely eliminated on October 1, 2018. The Company estimates that $196 million of the tax loss generated during the Predecessor period ended December 15, 2017 will be absorbed by taxable income generated during the Successor period ending September 30, 2018. These estimates are subject to revision and any changes in the estimates will affect income or loss from continuing operations in the Successor period ending September 30, 2018. Prior to September 30, 2017, a full valuation allowance was established in any jurisdiction that had a net deferred tax asset. A portion of the U.S. valuation allowance in the amount of $787 million was reversed as part of the reorganization adjustments as it was previously established against (i) the NOL and tax credits which will be eliminated as a result of the CODI rules and (ii) other deferred tax assets that were previously established for liabilities that were discharged in the Plan of Reorganization and eliminated as part of the reorganization adjustments. The valuation allowance in the amount of $47 million was reversed in certain non U.S. jurisdictions as part of the reorganization adjustments as management concluded it is more likely than not that the related deferred tax assets will be realized. The remaining U.S. valuation allowance in the amount of $461 million was reversed as part of the fresh start adjustments because management concluded it is more likely than not that the deferred tax assets will be realized primarily due to future sources of taxable income that will be generated by the reversal of deferred tax liabilities established in the fresh start adjustments. On December 22, 2017, the Act was signed into law. The Act lowered the U.S. federal corporate tax rate from 35% to 21% effective January 1, 2018. Corporations with a fiscal year-end that is not a calendar year but includes January 1, 2018 are subject to a blended tax rate based on the number of days in the fiscal year before and after January 1, 2018. The Company has a September 30 th tax year-end and therefore the U.S. federal tax rate for the year ending September 30, 2018 is 24.5% . The SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”) on December 22, 2017 which provided guidance to registrants on the accounting for tax related impacts under the Act. The guidance provides a measurement period of up to one year after the enactment date for companies to complete the tax accounting implications of the Act. As of the first quarter, the Company has provided a provisional estimate related to the revaluation of its deferred taxes and the deemed repatriation of unremitted foreign earnings. We will continue to refine our estimate, which could result in a material adjustment, given additional guidance under the Act, interpretations, available information and assumptions made by the Company. As a fiscal year-end tax filer, we are subject to various provisions under the Act for fiscal year 2018, including the change to the U.S. federal statutory tax rate and the mandatory deemed repatriation of unremitted foreign earnings. Beginning in our 2019 fiscal year, various other newly enacted provisions will become effective, including provisions that may result in the current U.S. taxation of certain income earned by the Company’s foreign subsidiaries. The FASB has published guidance (Topic 740, No. 5), regarding how to account for the Global Intangible Low-Taxed Income (“GILTI”) provisions included in the Act. The guidance states that a company may make a policy decision with respect to the accounting for taxes related to GILTI and whether deferred taxes should be established. The Company estimates that it will generate income that may be taxed as GILTI beginning in fiscal 2019. On a provisional basis, no deferred taxes have been established for GILTI as of December 31, 2018. The Company does not expect to incur a cash tax liability with respect to the one-time tax on foreign earnings due to historical foreign deficits. The Company previously established a deferred tax liability for non-U.S. withholding taxes to be incurred upon the remittance of foreign earnings. The Condensed Consolidated Financial Statements for the Predecessor and Successor periods include an adjustment for such withholding taxes attributable to current period earnings. In prior periods, the Company established a U.S. deferred income tax liability for certain foreign earnings under the assumption that such earnings would be remitted to the U.S. This deferred tax liability has been adjusted in the Successor period based on the taxation of such earnings under the Act. A net deferred tax liability was established at the U.S. federal tax rates in effect on December 15, 2017 as part of fresh start accounting for U.S. book-to-tax differences. These deferred taxes are primarily related to differences arising from recording intangible and other assets at fair market value. As of the December 22, 2017 enactment date of the Act, deferred taxes were adjusted to reflect the new tax rates in effect as of the date the deferred tax amounts are expected to be realized. The provisional amount of the reduction to the net deferred tax liability as a result of the ACT is $245 million and has been recorded as an income tax benefit from continuing operations in the Successor period.

Benefit Obligations

Benefit Obligations	3 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Benefit Obligations	Benefit Obligations The Company sponsors non-contributory defined benefit pension plans covering a portion of its U.S. employees and retirees, and post-retirement benefit plans covering a portion of its U.S. retirees that include healthcare benefits and life insurance coverage. Certain non-U.S. operations have various retirement benefit programs covering substantially all of their employees. Some of these programs are considered to be defined benefit pension plans for accounting purposes. Effective January 25, 2018, the Company and the Communications Workers of America (“CWA”) and the International Brotherhood of Electrical Workers (“IBEW”), agreed to extend the 2009 Collective Bargaining Agreement (“CBA”), previously extended through June 14, 2018, until September 21, 2019. The contract extensions did not affect the Company’s obligation for pension and post-retirement benefits available to U.S. employees of the Company who are represented by the CWA or IBEW (“represented employees”). In September 2015, the Company amended the post-retirement medical plan for represented retirees effective January 1, 2017, to replace medical coverage through the Company’s group plan for represented retirees who are retired as of October 15, 2015 and their eligible dependents, with medical coverage through the private and public insurance marketplace. The change allows the existing retirees to choose insurance from the marketplace and receive financial support from the Company toward the cost of coverage through a Health Reimbursement Arrangement ("HRA"). The components of the pension and post-retirement net periodic benefit cost (credit) for the periods indicated are provided in the tables below: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Pension Benefits - U.S. Components of Net Periodic Benefit Cost Service cost $ — $ 1 $ 1 Interest cost 1 22 24 Expected return on plan assets (2 ) (38 ) (45 ) Amortization of previously unrecognized net actuarial loss — 20 26 Settlement loss (1) — — — Net periodic benefit cost $ (1 ) $ 5 $ 6 (1) Excludes Plan of Reorganization related settlements discussed below that were recorded in Reorganization items, net in the Condensed Consolidated Statements of Operations. Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Pension Benefits - Non-U.S. Components of Net Periodic Benefit Cost Service cost $ — $ 2 $ 2 Interest cost — 3 2 Amortization of previously unrecognized net actuarial loss — 1 3 Net periodic benefit cost $ — $ 6 $ 7 Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Post-retirement Benefits - U.S. Components of Net Periodic Benefit Cost Interest cost $ — $ 3 $ 3 Expected return on plan assets — (2 ) (2 ) Amortization of unrecognized prior service cost — (3 ) (4 ) Amortization of previously unrecognized net actuarial loss — 2 3 Curtailment — — (4 ) Net periodic benefit cost $ — $ — $ (4 ) On December 15, 2017 , the APPSE, a qualified pension plan, was settled with the PBGC. At that time, the Company and the PBGC executed a termination and trusteeship agreement to terminate the APPSE and to appoint the PBGC as the statutory trustee of the plan. The Company also paid settlement consideration to the PBGC consisting of $340 million in cash and 6.1 million shares of Successor Company common stock (fair value of $90 million ). With this payment, any accrued but unpaid minimum funding contributions due were deemed to have been paid in full. As a result of the plan termination on December 15, 2017 , the Company's projected benefit obligation and pension trust assets were reduced by $2,192 million and $1,573 million , respectively. Including the settlement consideration and $703 million of Accumulated other comprehensive loss recorded in the Condensed Consolidated Balance Sheet, a settlement loss of $514 million was recorded in Reorganization items, net in the Condensed Consolidated Statement of Operations. On December 15, 2017 , the unfunded ASPP, a non-qualified excess benefit pension plan, was also terminated and settled. Benefit liabilities for ASPP participants were included as allowed claims in the general unsecured recovery pool. Settlement consideration of $17 million in the form of allowed claims payable to ASPP participants was estimated based upon claims data as of the Emergence Date as amounts due to individual general unsecured creditors had not been finalized and paid. As a result of the termination, the Company's projected benefit obligation was reduced by $88 million . Including the settlement consideration and $18 million of Accumulated other comprehensive loss recorded in the Condensed Consolidated Balance Sheet, a settlement gain of $53 million was recorded in Reorganization items, net in the Condensed Consolidated Statements of Operations. The Company's general funding policy with respect to its U.S. qualified pension plans is to contribute amounts at least sufficient to satisfy the minimum amount required by applicable laws and regulations, or to directly pay benefits where appropriate. As a result of the Bankruptcy Filing in January 2017, there was an automatic stay on the Company's contributions to the U.S. pension plans during fiscal 2017 . Therefore, the minimum funding requirements for the U.S. pension plans were not met during fiscal 2017 . The Plan of Reorganization included contributions to or settlements of all U.S. pension plans, which are the Avaya Pension Plan for Represented Employees ("APP"), the APPSE and the ASPP. On December 15, 2017 , the Company paid the aggregate unpaid required minimum funding for the APP, a qualified plan, of $49 million . Remeasurement as a result of fresh start accounting increased the APP and other post-retirement benefit plan obligations by $3 million on December 15, 2017 . The Company made no contributions to satisfy minimum statutory funding requirements for its U.S. funded defined benefit pension plans for the period from December 16, 2017 through December 31, 2017 (Successor) and for the period from October 1, 2017 through December 15, 2017 (Predecessor), exclusive of the payments discussed above as part of the Plan of Reorganization for the APP and settlement consideration to the PBGC for the APPSE. Estimated payments to satisfy minimum statutory funding requirements for the remainder of fiscal 2018 are $43 million . The Company provided pension benefits for U.S. employees, which were not pre-funded. Consequently, the Company made payments as the benefits were disbursed or claims were paid. For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company made payments for the U.S. pension benefits in each of the periods of amounts totaling less than $1 million . The Company provides for certain pension benefits for non-U.S. employees, the majority of which are not pre-funded. The Company made payments for these non-U.S. pension benefits for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor) totaling $1 million and $3 million , respectively. Estimated payments for these non-U.S. pension benefits for the remainder of fiscal 2018 are $24 million . During the period from December 16, 2017 through December 31, 2017 (Successor), the Company was reimbursed $3 million from the represented employees’ post-retirement health trust for claims paid that exceeded the Company's obligations. During the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company contributed $2 million to the represented employees’ post-retirement health trust to fund current benefit claims and costs of administration in compliance with the terms of the CBA, as extended through September 21, 2019. Estimated payments under the terms of the 2009 agreement as extended are $12 million for the remainder of fiscal 2018 . The Company also provides certain retiree medical benefits for U.S. employees through an HRA, which are not pre-funded. Consequently, the Company makes payments as these benefits are disbursed. For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company made payments in each of the periods totaling less than $1 million for these retiree medical benefits. Estimated payments for these retiree medical benefits for the remainder of fiscal 2018 are less than $1 million .

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Share-based Compensation	Share-based Compensation The Predecessor Company's common and preferred stock were cancelled and new common stock was issued on the Emergence Date. Accordingly, the Predecessor Company's then existing share-based compensation awards were also cancelled, which resulted in the recognition of any previously unamortized expense on the date of cancellation. Share-based compensation for the Successor and Predecessor periods are not comparable. Successor Pursuant to terms of the Plan of Reorganization, the Avaya Holdings Corp. 2017 Equity Incentive Plan ("2017 Equity Incentive Plan") became effective on the Emergence Date. The Successor Company's Board of Directors or any committee duly authorized thereby, will administer the 2017 Equity Incentive Plan. The administrator has broad authority to, among other things: (i) select participants; (ii) determine the types of awards that participants are to receive and the number of shares that are to be granted under such awards; and (iii) establish the terms and conditions of awards, including the price to be paid for the shares or the award. Persons eligible to receive awards under the 2017 Equity Incentive Plan include non-employee directors, employees of the Successor Company or any of its affiliates, and certain consultants and advisors to the Successor Company or any of its affiliates. The types of awards that may be granted under the 2017 Equity Incentive Plan include stock options, restricted stock, restricted stock units, performance awards and other forms of awards granted or denominated in shares of Successor common stock, as well as certain cash-based awards. The maximum number of shares of common stock that may be issued or granted under the 2017 Equity Incentive Plan is 7.4 million shares. If any option or other stock-based award granted under the 2017 Equity Incentive Plan expires, terminates or is cancelled for any reason without having been exercised in full, the number of shares of common stock underlying any unexercised award will again be available for the purpose of awards under the 2017 Equity Incentive Plan. If any shares of restricted stock, performance awards or other stock-based awards denominated in shares of common stock awarded under the 2017 Equity Incentive Plan to a participant are forfeited for any reason, the number of forfeited shares of restricted stock, performance awards or other stock-based awards denominated in shares of common stock will again be available for purposes of awards under the 2017 Equity Incentive Plan. Any award under the 2017 Equity Incentive Plan settled in cash will not be counted against the foregoing maximum share limitations. Shares withheld by the Company in satisfaction of the applicable exercise price or withholding taxes upon the issuance, vesting or settlement of awards, in each case, shall not be available for future issuance under the 2017 Equity Incentive Plan. The aggregate grant date fair value of all awards granted to any non-employee director during any calendar year (excluding awards made pursuant to deferred compensation arrangements made in lieu of all or a portion of cash retainers and any dividends payable in respect of outstanding awards) may not exceed $750,000 . On the Emergence Date, the Company granted 3.4 million restricted stock units and 1.2 million stock options to executives and other employees. The awards are subject to time based vesting. There are 2.8 million shares remaining under the 2017 Equity Incentive Plan available to be granted. The fair value of the premium-priced stock options granted on the Emergence Date was determined using a lattice option pricing model with the following assumptions: Exercise price $ 19.46 Expected term (in years) (1) 8.54 Volatility (2) 65.37 % Risk-free rate (3) 2.35 % Dividend yield (4) — % ( 1) Expected term based on the vesting terms of the option and a contractual life of ten years . (2) Volatility based on peer group companies adjusted for the Company's leverage. (3) Risk-free rate based on U.S. Treasury yields with a term equal to the expected option term. (4) Dividend yield was assumed to be zero as the Company does not anticipate paying dividends. At December 31, 2017, all share-based awards granted by the Successor Company were unvested and the related share-based compensation expense recorded for the period from December 16, 2017 through December 31, 2017 (Successor) was $1 million . Predecessor Prior to the Emergence Date, the Predecessor Company had granted share-based awards that were cancelled upon emergence from bankruptcy. In conjunction with the cancellation, the Predecessor Company accelerated the unrecognized share-based compensation expense and recorded $3 million of compensation expense in the period from October 1, 2017 through December 15, 2017 .

Capital Stock

Capital Stock	3 Months Ended
	Dec. 31, 2017
Stockholders' Equity Attributable to Parent [Abstract]
Capital Stock	Successor Preferred Stock. The Successor Company's certificate of incorporation authorizes it to issue up to 55.0 million shares of preferred stock with a par value of $0.01 per share. As of December 31, 2017 , there were no preferred shares issued or outstanding. Common Stock. The Successor Company's certificate of incorporation authorizes it to issue up to 550.0 million shares of common stock with a par value of $0.01 per share. As of December 31, 2017 , there were 110.0 million shares issued and 109.8 million outstanding. The outstanding shares were issued to (1) holders of Predecessor first lien obligations ( 99.3 million shares); (2) holders of Predecessor second lien obligations ( 4.4 million shares); and (3) PBGC ( 6.1 million shares). Issued but not outstanding are the shares held on behalf of the general unsecured creditor reserve or the holders of Predecessor first lien debt obligations ( 0.2 million shares). Predecessor In connection with the Company's Plan of Reorganization and emergence from bankruptcy, all equity interests in the Predecessor Company were cancelled, including preferred and common stock, warrants and equity-based awards.

Earnings (Loss) Per Common Shar

Earnings (Loss) Per Common Share	3 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings (Loss) Per Common Share	Earnings (Loss) Per Common Share All outstanding shares of common stock and common stock equivalents of the Predecessor Company were cancelled pursuant to the Plan of Reorganization. Upon emergence, the Successor Company authorized and issued 110.0 million shares of common stock of which 109.8 million shares were outstanding at December 31, 2017 and used as the basis for determining earnings per share. Basic earnings per share are calculated by dividing net income attributable to common stockholders by the weighted average number of common shares outstanding. Diluted earnings per share reflect the potential dilution that would occur if equity awards granted under the various share-based compensation plans were vested or exercised resulting in the issuance of common shares that would participate in the earnings of the Company. The following table sets forth the calculation of net income attributable to common shareholders and the computation of basic and diluted earnings (loss) per share for the periods indicated: Successor Predecessor (In millions, except per share amounts) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Net income (loss) per share: Numerator Net income (loss) $ 237 $ 2,977 $ (103 ) Dividends to preferred stockholders — (6 ) (8 ) Undistributed earnings 237 2,971 (111 ) Percentage allocated to common stockholders (1) 100.0 % 86.9 % 100.0 % Numerator for basic and diluted earnings per common share $ 237 $ 2,582 $ (111 ) Denominator Denominator for basic earnings per weighted average common shares 109.8 497.3 497.0 Effect of dilutive securities Restricted stock units 0.5 — — Stock options — — — Warrants — — — Denominator for diluted earnings per weighted average common shares 110.3 497.3 497.0 Per common share net income (loss) Basic $ 2.16 $ 5.19 $ (0.22 ) Diluted $ 2.15 $ 5.19 $ (0.22 ) (1) Basic weighted average common stock outstanding 109.8 497.3 497.0 Basic weighted average common stock and common stock equivalents (preferred shares) 109.8 572.4 497.0 Percentage allocated to common stockholders 100.0 % 86.9 % 100.0 % There were 0.5 million dilutive securities for the period from December 16, 2017 through December 31, 2017 (Successor).

Operating Segments

Operating Segments	3 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Reportable Segments	Segments On July 14, 2017, the Company sold its Networking business to Extreme. Prior to the sale, the Company had three separate operating segments. After the sale, the Company has two operating segments, GCS representing the Company's products portfolio and AGS representing the Company's services portfolio. Both GCS and Networking made up the Company’s Enterprise Collaboration Solutions ("ECS") products portfolio. The GCS segment primarily develops, markets, and sells unified communications and contact center solutions, offered on premises, in the cloud, or as a hybrid solution. These integrate multiple forms of communications, including telephony, e-mail, instant messaging and video. The AGS segment develops, markets and sells comprehensive end-to-end global service offerings that enable customers to evaluate, plan, design, implement, monitor, manage and optimize even complex enterprise communications networks. The Networking segment portfolio of software and hardware products offered integrated networking products. The Company’s chief operating decision maker makes financial decisions and allocates resources based on segment profit information obtained from the Company’s internal management systems. Management does not include in its segment measures of profitability selling, general, and administrative expenses, research and development expenses, amortization of intangible assets, and certain discrete items, such as charges relating to restructuring actions, impairment charges, and merger-related costs as these costs are not core to the measurement of segment performance, but rather are controlled at the corporate level. Summarized financial information relating to the Company’s operating segments is shown in the following table for the periods indicated: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 REVENUE Global Communications Solutions $ 71 $ 253 $ 343 Avaya Networking (1) — — 58 Enterprise Collaboration Solutions 71 253 401 Avaya Global Services 77 351 474 $ 148 $ 604 $ 875 GROSS PROFIT Global Communications Solutions $ 41 $ 169 $ 231 Avaya Networking (1) — — 25 Enterprise Collaboration Solutions 41 169 256 Avaya Global Services 50 196 284 Unallocated Amounts (2) (13 ) (3 ) (5 ) 78 362 535 OPERATING EXPENSES Selling, general and administrative 50 264 336 Research and development 9 38 62 Amortization of intangible assets 7 10 57 Restructuring charges, net 10 14 10 76 326 465 OPERATING INCOME 2 36 70 INTEREST EXPENSE, OTHER (EXPENSE) INCOME, NET AND REORGANIZATION ITEMS, NET (11 ) 3,400 (170 ) (LOSS) INCOME BEFORE INCOME TAXES $ (9 ) $ 3,436 $ (100 ) (1) The Networking business was sold on July 14, 2017. (2) Unallocated Amounts in Gross Profit include the effect of the amortization of technology intangibles and costs that are not core to the measurement of segment management’s performance, but rather are controlled at the corporate level.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Loss The components of accumulated other comprehensive income (loss) for the periods indicated are summarized as follows: (In millions) Change in unamortized pension, post-retirement and postemployment benefit-related items Foreign Currency Translation Other Accumulated Other Comprehensive Income (Loss) Beginning balance September 30, 2016 (Predecessor) $ (1,627 ) $ (33 ) $ (1 ) $ (1,661 ) Other comprehensive income before reclassifications — 19 — 19 Amounts reclassified to earnings 20 — — 20 (Provision for) benefit from income taxes (6 ) 4 — (2 ) Ending balance December 31, 2016 (Predecessor) $ (1,613 ) $ (10 ) $ (1 ) $ (1,624 ) (In millions) Change in unamortized pension, post-retirement and postemployment benefit-related items Foreign Currency Translation Other Accumulated Other Comprehensive Income (Loss) Beginning balance October 1, 2017 (Predecessor) $ (1,375 ) $ (72 ) $ (1 ) $ (1,448 ) Other comprehensive (loss) income before reclassifications (24 ) 3 — (21 ) Amounts reclassified to earnings 16 — — 16 Pension settlement 721 — — 721 Provision for income taxes (58 ) — — (58 ) Ending balance December 15, 2017 (Predecessor) (720 ) (69 ) (1 ) (790 ) Elimination of Predecessor Company accumulated other comprehensive loss 720 69 1 790 Ending balance December 15, 2017 (Predecessor) $ — $ — $ — $ — Beginning balance December 15, 2017 (Successor) $ — $ — $ — $ — Other comprehensive loss before reclassifications — (13 ) — (13 ) Ending balance December 31, 2017 (Successor) $ — $ (13 ) $ — $ (13 ) The amounts reclassified out of accumulated other comprehensive loss are reclassified to Other (expense) income, net in the Condensed Consolidated Statements of Operations prior to the impact of income taxes.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Pursuant to the Plan of Reorganization confirmed by the Bankruptcy Court, the Successor Company's Board of Directors is comprised of seven directors, including the Successor Company's Chief Executive Officer, James M. Chirico, Jr., and six non-employee directors, William D. Watkins, Ronald A. Rittenmeyer, Stephan Scholl, Susan L. Spradley, Stanley J. Sutula, III and Scott D. Vogel. Specific Arrangements Involving the Company’s Directors and Executive Officers Laurent Philonenko is a Senior Vice President of Avaya Holdings and became an Advisor to Koopid, Inc., a software development company specializing in mobile applications, in February 2017. For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company purchased goods and services from Koopid, Inc. for each of the periods for less than $1 million . Ronald A. Rittenmeyer is a Director of Avaya Holdings. Mr. Rittenmeyer serves on the board of directors of Tenet Healthcare Corporation (“Tenet Healthcare”), a healthcare services company, and serves on the board of directors of American International Group, Inc. (“AIG”), a global insurance organization. For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), sales of the Company’s products and services to Tenet Healthcare for each of the periods were less than $1 million . For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), sales of the Company’s products and services to AIG were less than $1 million and $2 million , respectively. Stanley J. Sutula III is a director of Avaya Holdings and he is Executive Vice President and Chief Financial Officer of Pitney Bowes Inc., a business-to-business provider of equipment, software and services. For the period from December 16, 2017 through December 31, 2017 (Successor), there were no sales of the Company's products and services to Pitney Bowes Inc. For the period from October 1, 2017 through December 15, 2017 (Predecessor) and for fiscal 2017 (Predecessor), sales of the Company’s products and services to Pitney Bowes Inc. for each of the periods were less than $1 million . William D. Watkins is a director and Chair of the Board of Directors of Avaya Holdings. Mr. Watkins currently serves on the board of directors of Flex Ltd., an electronics design manufacturer. For the period from December 16, 2017 through December 31, 2017 (Successor), the period from October 1, 2017 through December 15, 2017 (Predecessor) and for fiscal 2017 , the Company purchased goods and services from subsidiaries of Flex Ltd. of $2 million , $6 million and $38 million , respectively. Specific Arrangements Among the Predecessor Company, Silver Lake Partners and TPG Capital and their Affiliates In connection with the Plan of Reorganization, all agreements between the Predecessor Company and Silver Lake Partners, TPG Capital and their affiliates (collectively, the "Predecessor Sponsors") were terminated on the Emergence Date, including the stockholders' agreement, registration rights agreement and management services agreement. In addition, all Predecessor Company equity held by the Predecessor Sponsors was cancelled. Predecessor Sponsor fees paid were less than $1 million for the period from October 1, 2017 through December 15, 2017 (Predecessor).

Commitments And Contingencies

Commitments And Contingencies	3 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings General The Company records accruals for legal contingencies to the extent that it has concluded it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. No estimate of the possible loss or range of loss in excess of amounts accrued, if any, can be made at this time regarding the matters specifically described below because the inherently unpredictable nature of legal proceedings may be exacerbated by various factors, including: (i) the damages sought in the proceedings are unsubstantiated or indeterminate; (ii) discovery is not complete; (iii) the proceeding is in its early stages; (iv) the matters present legal uncertainties; (v) there are significant facts in dispute; (vi) there are a large number of parties (including where it is uncertain how liability, if any, will be shared among multiple defendants); or (vii) there is a wide range of potential outcomes. In the ordinary course of business, the Company is involved in litigation, claims, government inquiries, investigations and proceedings, including, but not limited to, those identified below, relating to intellectual property, commercial, employment, environmental and regulatory matters. The Company believes that it has meritorious defenses in connection with its current lawsuits and material claims and disputes, and intends to vigorously contest each of them. Based on the Company's experience, management believes that the damages amounts claimed in a case are not a meaningful indicator of the potential liability. Claims, suits, investigations and proceedings are inherently uncertain and it is not possible to predict the ultimate outcome of cases. Other than as described below, in the opinion of the Company's management based upon information currently available to the Company, while the outcome of these lawsuits, claims and disputes is uncertain, the likely results of these lawsuits, claims and disputes are not expected, either individually or in the aggregate, to have a material adverse effect on the Company's financial position, results of operations or cash flows, although the effect could be material to the Company's consolidated results of operations or consolidated cash flows for any interim reporting period. During the period December 16, 2017 through December 31, 2017 (Successor), October 1, 2017 through December 15, 2017 (Predecessor) and the three months ended December 31, 2016 (Predecessor), costs incurred in connection with certain legal matters was $0 million , $37 million and $0 million , respectively. Antitrust Litigation In 2006, the Company instituted an action in the U.S. District Court, District of New Jersey, against defendants Telecom Labs, Inc., TeamTLI.com Corp. and Continuant Technologies, Inc. (“TLI/Continuant”) and subsequently amended its complaint to include certain individual officers of these companies as defendants. Defendants purportedly provide maintenance services to customers who have purchased or leased the Company's communications equipment. The Company asserted in its amended complaint that, among other things, defendants, or each of them, engaged in tortious conduct by improperly accessing and utilizing the Company's proprietary software, including passwords, logins and maintenance service permissions, to perform certain maintenance services on the Company's customers' equipment. TLI/Continuant filed counterclaims against the Company alleging that the Company has violated the Sherman Act's prohibitions against anticompetitive conduct through the manner in which the Company sells its products and services. TLI/Continuant sought to recover the profits they claim they would have earned from maintaining Avaya's products, and asked for injunctive relief prohibiting the conduct they claim is anticompetitive. The trial commenced on September 9, 2013. On January 7, 2014, the Court issued an order dismissing the Company's affirmative claims. With respect to TLI/Continuant’s counterclaims, on March 27, 2014, a jury found against the Company on two of eight claims and awarded damages of $20 million . Under the federal antitrust laws, the jury’s award is subject to automatic trebling, or $60 million . Following the jury verdict, TLI/Continuant sought an injunction regarding the Company’s ongoing business operations. On June 30, 2014, a federal judge rejected the demands of TLI/Continuant’s proposed injunction and stated that “only a narrow injunction is appropriate.” Instead, the judge issued an order relating to customers who purchased an Avaya PBX system between January 1, 1990 and April 30, 2008 only. Those customers and their agents will have free access to the on demand maintenance commands that were installed on their systems at the time of the purchase transaction. The court specified that this right “does not extend to access on a system purchased after April 30, 2008.” Consequently, the injunction affected only systems sold prior to April 30, 2008. The judge denied all other requests TLI/Continuant made in its injunction filing. The Company complied with the injunction although it has now been vacated by the September 30, 2016 decision discussed below. The Company and TLI/Continuant filed post-trial motions seeking to overturn the jury’s verdict, which motions were denied. In September 2014, the Court entered judgment in the amount of $63 million , which included the jury's award of $20 million , subject to automatic trebling, or $60 million , plus prejudgment interest in the amount of $3 million . On October 10, 2014, the Company filed a Notice of Appeal, and on October 23, 2014, TLI/Continuant filed a Notice of Conditional Cross-Appeal. On October 23, 2014, the Company filed its supersedeas bond with the Court in the amount of $63 million . The Company secured posting of the bond through the issuance of a letter of credit under its then existing credit facilities. On November 10, 2014, TLI/Continuant made an application for attorney's fees, expenses and costs, which the Company contested. TLI/Continuant’s application for attorneys’ fees, expenses and costs was approximately $71 million and represented activity through February 28, 2015. On February 22, 2016, the Company posted a bond in the amount of $8 million in connection with TLC/Continuant's attorneys' fees application. In September 2016, a Special Master appointed by the trial court to assist in evaluating TLI/Continuant's application rendered a Recommendation, finding that TLI/Continuant should receive approximately $61 million in attorneys' fees, expenses and costs. Subsequently, the parties submitted letters to the Special Master seeking an Amended Recommendation. However, in light of the Third Circuit's favorable opinion, outlined below, the trial court proceedings relating to TLI/Continuant's application have not proceeded. TLI/Continuant is no longer entitled to attorneys' fees, expenses and costs, because it no longer is a prevailing party, subject to further proceedings on appeal or retrial. On September 30, 2016, the Third Circuit issued a favorable ruling for the Company, which included: (1) reversing the mid-trial decision to dismiss four of the Company’s affirmative claims and reinstated them; (2) vacating the jury verdict on the two claims decided in TLI/Continuant’s favor; (3) entering judgment in the Company’s favor on a portion of TLI/Continuant’s claim relating to attempted monopolization; (4) dismissing TLI/Continuant’s PDS patches claim as a matter of law; (5) vacating the damages award to TLI/Continuant; (6) vacating the award of prejudgment interest to TLI/Continuant; and (7) vacating the injunction. On October 28, 2016, TLI/Continuant sought panel rehearing or rehearing en banc review of the opinion, which was denied on November 16, 2016. On November 22, 2016, TLI/Continuant filed a Motion for Stay of Mandate, which was denied. On December 5, 2016, the Third Circuit issued a certified judgment in lieu of a formal mandate, returning jurisdiction to the trial court. As a result of the Third Circuit’s opinion, on November 23, 2016, the Company filed a Notice of Motion to Release the Supersedeas Bonds, which the court granted on December 23, 2016. On December 12, 2016, the Court issued an Order Upon Mandate and For Status Conference, which i) vacated the Court’s January 7, 2014 order dismissing Avaya’s claims against TLI/Continuant and the order of judgment entered on September 17, 2014 and ii) scheduled a status conference for January 6, 2017 to discuss the Joint Plan for Retrial. On January 13, 2017, the Court entered an Order staying the matter pending mediation. On January 20, 2017, the Company filed a Notice of Suggestion on Pendency of Bankruptcy For Avaya Inc., et. al. and Automatic Stay of Proceedings. TLI/Continuant filed a proof of claim in the Bankruptcy Court. On November 30, 2017, the Company filed a motion in the Bankruptcy Court seeking to estimate TLI/Continuant’s claim. A loss reserve has been provided for this matter. The Company continues to believe that TLI/Continuant’s claims are without merit and unsupported by the facts and law, and the Company continues to defend this matter. At this time an outcome cannot be predicted and, as a result, the Company cannot be assured that this case will not have a material adverse effect on the manner in which it does business, its financial position, results of operations, or cash flows. Patent Infringement In July 2016, BlackBerry Limited (“BlackBerry”) filed a complaint for patent infringement against the Company in the Northern District of Texas, alleging infringement of multiple patents with respect to a variety of technologies including user interface design, encoding/decoding and call routing. In September 2016, the Company filed a motion to dismiss these claims and in October 2016, the Company also filed a motion to transfer this matter to the Northern District of California. In January 2017, the Company filed a notice of Suggestion of Pendency of Bankruptcy, which initially stayed the proceedings. The stay was partially lifted to allow the court in Texas to rule on the two pending motions. The Company’s motion to transfer the case from Texas to California has been denied. The Company’s motion to dismiss BlackBerry’s indirect infringement and willfulness claims was granted, although BlackBerry was provided an opportunity to file an Amended Complaint to cure the deficiencies, which it did on October 19, 2017. BlackBerry filed a proof of claim in the Bankruptcy Court. On February 20, 2018, the Company and BlackBerry entered into a settlement agreement resolving this dispute, and the Company shortly expects the Court in the Northern District of Texas to enter an order dismissing the lawsuit, with prejudice. A loss reserve has been established for this matter. The Company considers this matter closed, except for distribution of the pre-petition allowed claim in accordance with the general unsecured claims procedure pursuant to the Company's Plan of Reorganization. In September 2011, Network-1 Security Solutions, Inc. (“Network-1”) filed a complaint for patent infringement against the Company and other corporations in the Eastern District of Texas (Tyler Division), alleging infringement of its patent with respect to power over Ethernet technology. Network-1 seeks to recover for alleged reasonable royalties, enhanced damages and attorneys’ fees. In January 2017, the Company filed a Notice of Suggestion of Pendency of Bankruptcy, which informed the Court of the Company’s voluntary bankruptcy petition filing and stay of proceedings. On October 16, 2017, the Bankruptcy Court entered an order approving a settlement agreement with Network-1 and on November 7, 2017 the Tyler Division district court entered an order dismissing the lawsuit, with prejudice. The Company considers this matter closed, except for distribution of the pre-petition allowed claim in accordance with the general unsecured claims procedure in the Company's Plan of Reorganization. Intellectual Property and Commercial Disputes In January 2010, SAE Power Incorporated and SAE Power Company (“SAE”) filed a complaint in the New Jersey Superior Court asserting various claims including breach of contract, unjust enrichment, promissory estoppel, and breach of the covenant of good faith and fair dealing arising out of Avaya’s relationship with SAE as a supplier of various power supply products. SAE has since asserted additional claims against Avaya for fraud, negligent misrepresentation, misappropriation of trade secrets, and civil conspiracy. SAE seeks to recover for alleged losses stemming from Avaya’s termination of its power supply purchases from SAE, including for Avaya’s alleged disclosure of SAE’s alleged trade secret and/or confidential information to another power supply vendor. On July 19, 2016, the Court entered an order granting Avaya’s motion for partial summary judgment, dismissing certain of SAE’s claims regarding the alleged disclosure of trade secrets. In January 2017, the Company filed a Notice of Suggestion of Pendency of Bankruptcy, which informed the Court of the Company’s voluntary bankruptcy petition filing and stay of proceedings. SAE filed a proof of claim in the Bankruptcy Court. On September 28, 2017, the Company filed a motion in the Bankruptcy Court seeking to estimate SAE’s claim, and the estimation hearing took place on February 15, 2018. The Bankruptcy Court has not yet decided the estimation motion. A loss reserve has been established for this matter. At this time an outcome cannot be predicted and, as a result, the Company cannot be assured that this case will not have a material adverse effect on the manner in which it does business, its financial position, results of operations or cash flows. In the ordinary course of business, the Company is involved in litigation alleging it has infringed upon third parties’ intellectual property rights, including patents and copyrights; some litigation may involve claims for infringement against customers, distributors and resellers by third parties relating to the use of Avaya’s products, as to which the Company may provide indemnifications of varying scope to certain parties. The Company is also involved in litigation pertaining to general commercial disputes with customers, suppliers, vendors and other third parties including royalty disputes. Much of the pending litigation against the Debtors has been stayed as result of the Chapter 11 filing and will be subject to resolution in accordance with the Bankruptcy Code and the orders of the Bankruptcy Court. Based on discussions with parties that have filed claims against the Debtors, the Company provided loss provisions for certain matters. However, these matters are on-going and the outcomes are subject to inherent uncertainties. As a result, the Company cannot be assured that any such matter will not have a material adverse effect on its financial position, results of operations or cash flows. Product Warranties The Company recognizes a liability for the estimated costs that may be incurred to remedy certain deficiencies of quality or performance of the Company’s products. These product warranties extend over a specified period of time generally ranging up to two years from the date of sale depending upon the product subject to the warranty. The Company accrues a provision for estimated future warranty costs based upon the historical relationship of warranty claims to sales. The Company periodically reviews the adequacy of its product warranties and adjusts, if necessary, the warranty percentage and accrued warranty reserve, which is included in other current and non-current liabilities in the Condensed Consolidated Balance Sheets, for actual experience. (In millions) Accrued warranty obligations as of September 30, 2017 (Predecessor) $ 2 Reductions for payments and costs to satisfy claims (1 ) Accruals for warranties issued during the period 1 Accrued warranty obligations as of December 15, 2017 (Predecessor) $ 2 Reductions for payments and costs to satisfy claims $ (1 ) Accruals for warranties issued during the period 1 Accrued warranty obligations as of December 31, 2017 (Successor) $ 2 Guarantees of Indebtedness and Other Off-Balance Sheet Arrangements Letters of Credit and Guarantees The Company provides guarantees, letters of credit and surety bonds to various parties as required for certain transactions initiated during the ordinary course of business to guarantee the Company's performance in accordance with contractual or legal obligations. As of December 31, 2017 (Successor), the maximum potential payment obligation with regards to letters of credit, guarantees and surety bonds was $61 million . The outstanding letters of credit are collateralized by restricted cash of $4 million included in other assets on the Condensed Consolidated Balance Sheets as of December 31, 2017 (Successor). Purchase Commitments and Termination Fees The Company purchases components from a variety of suppliers and uses several contract manufacturers to provide manufacturing services for its products. During the normal course of business, in order to manage manufacturing lead times and to help assure adequate component supply, the Company enters into agreements with contract manufacturers and suppliers that allow them to produce and procure inventory based upon forecasted requirements provided by the Company. If the Company does not meet these specified purchase commitments, it could be required to purchase the inventory, or in the case of certain agreements, pay an early termination fee. Historically, the Company has not been required to pay a charge for not meeting its designated purchase commitments with these suppliers, but has been obligated to purchase certain excess inventory levels from its outsourced manufacturers due to actual sales of product varying from forecast and due to transition of manufacturing from one vendor to another. The Company’s outsourcing agreements with its most significant contract manufacturers automatically renew in July and September for successive periods of twelve months each, subject to specific termination rights for the Company and the contract manufacturers. All manufacturing of the Company’s products is performed in accordance with either detailed requirements or specifications and product designs furnished by the Company, and is subject to rigorous quality control standards. Long-Term Incentive Cash Bonus Plan The Predecessor Company had established a long-term incentive cash bonus plan (“LTIP”). Under the LTIP, the Predecessor Company would pay cash awards and recognize compensation expense to certain key employees upon specific triggering events. As of the Emergence Date, no triggering event had occurred, therefore no cash awards were paid and no compensation expense recognized. Upon emergence from bankruptcy, all awards to persons deemed "insiders" for purposes of Chapter 11 proceedings were cancelled. Credit Facility Indemnification In connection with the Successor Company's obligations under its post-emergence credit facilities, the Company has agreed to indemnify the third-party lending institutions for costs incurred by the institutions related to non-compliance with environmental law and other liabilities that may arise with respect to the execution, delivery, enforcement, performance and administration of the financing documentation. As of December 31, 2017 (Successor), no amounts were paid or accrued pursuant to this indemnity. Transactions with Nokia Pursuant to the Contribution and Distribution Agreement effective October 1, 2000, Lucent Technologies, Inc. (now Nokia) contributed to the Company substantially all of the assets, liabilities and operations associated with its enterprise networking businesses (the “Company’s Businesses”) and distributed the Company’s stock pro-rata to the shareholders of Lucent (“distribution”). The Contribution and Distribution Agreement, among other things, provides that, in general, the Company will indemnify Nokia for all liabilities including certain pre-distribution tax obligations of Nokia relating to the Company’s Businesses and all contingent liabilities primarily relating to the Company’s Businesses or otherwise assigned to the Company. In addition, the Contribution and Distribution Agreement provides that certain contingent liabilities not allocated to one of the parties will be shared by Nokia and the Company in prescribed percentages. The Contribution and Distribution Agreement also provides that each party will share specified portions of contingent liabilities based upon agreed percentages related to the business of the other party that exceed $50 million . The Company is unable to determine the maximum potential amount of other future payments, if any, that it could be required to make under this agreement. In addition, in connection with the distribution, the Company and Lucent entered into a Tax Sharing Agreement that governs Nokia’s and the Company’s respective rights, responsibilities and obligations after the distribution with respect to taxes for the periods ending on or before the distribution. Generally, pre-distribution taxes or benefits that are clearly attributable to the business of one party will be borne solely by that party and other pre-distribution taxes or benefits will be shared by the parties based on a formula set forth in the Tax Sharing Agreement. The Company may be subject to additional taxes or benefits pursuant to the Tax Sharing Agreement related to future settlements of audits by state and local and foreign taxing authorities for the periods prior to the Company’s separation from Nokia.

Condensed Financial Information

Condensed Financial Information of Parent Company	3 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company	Condensed Financial Information of Parent Company Avaya Holdings has no material assets or stand-alone operations other than its ownership in Avaya Inc. and its subsidiaries. These condensed financial statements have been presented on a "Parent Company only" basis. Under a Parent Company only presentation, the Company's investments in its consolidated subsidiaries are presented using the equity method of accounting. These Parent Company only condensed financial statements should be read in conjunction with the Company's Condensed Consolidated Financial Statements. The following present: (1) the Successor Company, Parent Company only, statements of financial position as of December 31, 2017 , and the statements of operations, comprehensive income (loss) and cash flows for the period from December 16, 2017 through December 31, 2017 , and; (2) the Predecessor Company, Parent Company only, statements of financial position as of September 30, 2017 , and the statements of operations, comprehensive income (loss) and cash flows for the period from October 1, 2017 through December 15, 2017 and for the three months ended December 31, 2016 . Avaya Holdings Corp. Parent Company Only Condensed Balance Sheets (unaudited) (In millions) Successor Predecessor December 31, 2017 September 30, 2017 ASSETS Investment in Avaya Inc. $ 1,867 $ — TOTAL ASSETS $ 1,867 $ — LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT) LIABILITIES Deficit in excess of investment in Avaya Inc. $ — $ 4,429 TOTAL LIABILITIES — 4,429 Commitments and contingencies Predecessor equity awards on redeemable shares — 7 Preferred stock, Series B — 393 Preferred stock, Series A — 184 TOTAL STOCKHOLDERS' EQUITY (DEFICIT) 1,867 (5,013 ) TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT) $ 1,867 $ — Avaya Holdings Corp. Parent Company Only Condensed Statements of Operations (unaudited) (In millions, except per share amounts) Successor Predecessor Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Equity in net income (loss) of Avaya Inc. $ 237 $ 2,977 $ (103 ) NET INCOME (LOSS) $ 237 $ 2,977 $ (103 ) NET INCOME (LOSS) PER SHARE AVAILABLE TO COMMON STOCKHOLDERS Basic $ 2.16 $ 5.19 $ (0.22 ) Diluted $ 2.15 $ 5.19 $ (0.22 ) Weighted average shares outstanding Basic 109.8 497.3 497.0 Diluted 110.3 497.3 497.0 Avaya Holdings Corp. Parent Company Only Condensed Statements of Comprehensive Income (Loss) (unaudited) (In millions) Successor Predecessor Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Net income (loss) $ 237 $ 2,977 $ (103 ) Equity in other comprehensive (loss) income of Avaya Inc. (13 ) 658 37 Elimination of Predecessor Company accumulated other comprehensive loss — 790 — Comprehensive income (loss) $ 224 $ 4,425 $ (66 ) Avaya Holdings Corp. Parent Company Only Condensed Statements of Cash Flows (unaudited) (In millions) Successor Predecessor Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three Months Ended December 31, 2016 Net income (loss) $ 237 $ 2,977 $ (103 ) Adjustments to reconcile net loss to net cash used for operating activities: Equity in net income (loss) of Avaya Inc. (237 ) (2,977 ) 103 Net cash provided by (used for) operating activities — — — Net cash provided by (used for) investing activities — — — Net cash provided by (used for) financing activities — — — Net increase (decrease) in cash and cash equivalents — — — Cash and cash equivalents at beginning of period — — — Cash and cash equivalents at end of period $ — $ — $ —

Subsequent Events

Subsequent Events	3 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On January 29, 2018, the Company entered into a definitive agreement to acquire Intellisist, Inc., doing business as Spoken Communications, a Contact Center as a Service (CCaaS) solutions company. The acquisition is expected to close within the next two months and be funded by cash on hand, however the ultimate purchase price and certain other terms are subject to further negotiation.

Accounting Policy Changes (Poli

Accounting Policy Changes (Policies)	3 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Avaya Holdings has no material assets or standalone operations other than its ownership in Avaya Inc. and its subsidiaries. The accompanying unaudited interim Condensed Consolidated Financial Statements as of December 31, 2017 and for the period from December 16, 2017 through December 31, 2017 , the period from October 1, 2017 through December 15, 2017 and the three months ended December 31, 2016 , reflect the operating results of Avaya Holdings and its consolidated subsidiaries, and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial statements, and should be read in conjunction with the Consolidated Financial Statements and other financial information for the fiscal year ended September 30, 2017 , included in Amendment No. 3 to the Company’s Form 10 filed with the SEC on January 10, 2018. In management’s opinion, these unaudited interim Condensed Consolidated Financial Statements reflect all adjustments, consisting of normal and recurring adjustments, necessary to present fairly the results of operations, financial position and cash flows for the periods indicated. The condensed consolidated results of operations for the interim periods reported are not necessarily indicative of our results for the entire fiscal year. Management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and revenue and expenses during the periods reported. These estimates include assessing the collectability of accounts receivable, sales returns and allowances, the use and recoverability of inventory, the realization of deferred tax assets, business restructuring reserves, pension and post-retirement benefit costs, the fair value of equity compensation, the fair value of assets and liabilities in connection with fresh start accounting as well as those acquired in business combinations, the recoverability of long-lived assets, useful lives and impairment of tangible and intangible assets including goodwill, the amount of exposure from potential loss contingencies, and fair value measurements, among others. The markets for the Company’s products are characterized by intense competition, rapid technological development and frequent new product introductions, all of which could affect the future recoverability of the Company’s assets. Estimates and assumptions are reviewed periodically and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Actual results could differ from these estimates. On January 19, 2017 (the “Petition Date”), Avaya Holdings, together with certain of its affiliates, namely Avaya CALA Inc., Avaya EMEA Ltd., Avaya Federal Solutions, Inc., Avaya Holdings LLC, Avaya Holdings Two, LLC, Avaya Inc., Avaya Integrated Cabinet Solutions Inc., Avaya Management Services Inc., Avaya Services Inc., Avaya World Services Inc., Octel Communications LLC, Sierra Asia Pacific Inc., Sierra Communication International LLC, Technology Corporation of America, Inc., Ubiquity Software Corporation, VPNet Technologies, Inc., and Zang, Inc. (the “Debtors”), filed voluntary petitions for relief (the “Bankruptcy Filing”) under Chapter 11 of the United States Bankruptcy Code (the “Bankruptcy Code’) in the United States Bankruptcy Court for the Southern District of New York (the “Bankruptcy Court’). The cases were jointly administered as Case No. 17-10089 (SMB). The Debtors operated their businesses as "debtors-in-possession" under the jurisdiction of the Bankruptcy Court and in accordance with the applicable provisions of Chapter 11 of the Bankruptcy Code and the orders of the Bankruptcy Court until their emergence from bankruptcy on December 15, 2017. Subsequent to the Petition Date, all expenses, gains and losses directly associated with the reorganization proceedings were reported as Reorganization items, net in the accompanying Condensed Consolidated Statements of Operations. In addition, Liabilities subject to compromise during Chapter 11 proceedings were distinguished from liabilities of the non-debtors and from post-petition liabilities in the accompanying Condensed Consolidated Balance Sheets. The Company's other subsidiaries that were not part of the Bankruptcy Filing ("non-debtors") continued to operate in the ordinary course of business. Upon emergence from bankruptcy on December 15, 2017 (the "Emergence Date"), the Company applied fresh start accounting, which resulted in a new basis of accounting and the Company becoming a new entity for financial reporting purposes. As a result of the application of fresh start accounting and the effects of the implementation of the Second Amended Joint Plan of Reorganization filed by the Debtors on October 24, 2017 and approved by the Bankruptcy Court on November 28, 2017 (the "Plan of Reorganization"), the consolidated financial statements after the Emergence Date, are not comparable with the consolidated financial statements on or before that date. Refer to Note 5, "Fresh Start Accounting," for additional information. The accompanying Condensed Consolidated Financial Statements of the Company have been prepared on a basis that assumes that the Company will continue as a going concern and contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. During the Chapter 11 proceedings, the Company's ability to continue as a going concern was contingent upon its ability to comply with the financial and other covenants contained in its debtor-in-possession credit agreement, the Bankruptcy Court's approval of the Company's Plan of Reorganization and the Company's ability to successfully implement the Plan of Reorganization, among other factors. As a result of the execution of the Plan of Reorganization, there is no longer substantial doubt about the Company's ability to continue as a going concern. References to "Successor" or "Successor Company" relate to the financial position and results of operations of the reorganized Avaya Holdings after the Emergence Date. References to "Predecessor" or "Predecessor Company" refer to the financial position and results of operations of Avaya Holdings on or before the Emergence Date.
Fair Value of Equity Awards	Fair Value of Equity Awards Successor Accounting Policy: The Black-Scholes-Merton option pricing model ("Black-Scholes") replaced the Cox-Ross-Rubinstein ("CRR") binomial option pricing model in calculating the fair value of equity awards, including the fair value of warrants to purchase common stock. In addition to the change in option pricing models, the Company now accounts for forfeitures as incurred. Predecessor Accounting Policy: The CRR binomial option pricing model was utilized to determine the grant date fair values of the equity awards, including the fair value of the Preferred Series A and B Stock warrants. Forfeitures was an input assumption in the valuation model.
Uncollected Deferred Revenue	Uncollected Deferred Revenue Successor Accounting Policy: The Company does not recognize deferred revenue relating to any sales transactions that have been billed, but for which the related account receivable has not yet been collected. The aggregate amount of unrecognized accounts receivable and deferred revenue was $100 million at December 31, 2017 . Predecessor Accounting Policy: The Company recorded the deferred revenue and related collectible accounts receivable in its consolidated balance sheets.
Foreign Currency	Foreign Currency Successor Accounting Policy: Income and expense of non-U.S. dollar functional currency subsidiaries are translated into U.S. dollars using an average rate for the period. Predecessor Accounting Policy: Income and expense of non-U.S. dollar functional currency subsidiaries are translated into U.S. dollars at the spot rate for the transaction.
Recently Adopted Accounting Policies	Recently Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-09, "Improvements to Employee Share-Based Payment Accounting." This standard simplifies the accounting for share-based payments and their presentation in the statements of cash flows as well as the income tax effects of share-based payments. The Company adopted this standard as of October 1, 2017 on a prospective basis. The adoption of this standard did not have a material impact on its Condensed Consolidated Financial Statements. In March 2017, the FASB issued ASU No. 2017-07, "Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost." This standard changes how employers that sponsor defined benefit pension and other post-retirement benefit plans present net periodic benefit cost in the income statement. This amendment requires that the service cost component be disaggregated from the other components of pension and post-retirement benefit costs on the income statement. The service cost component is reported in the same line items as other compensation costs and the other components of pension and post-retirement benefit costs (including interest cost, expected return on plan assets, amortization and curtailments and settlements) are reported in Other income (expense), net in the Company's Condensed Consolidated Financial Statements. The Company early adopted this accounting standard as of October 1, 2017. Changes to the Condensed Consolidated Financial Statements have been applied retrospectively. As a result, the Company reclassified $(6) million of other pension and post-retirement benefit costs to other income (expense), net for the three months ended December 31, 2016 (Predecessor). For the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor), the Company recorded $1 million and $(8) million , respectively, of other pension and post-retirement benefit costs in other income (expense), net. Recent Standards Not Yet Effective In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers.” This standard supersedes most of the current revenue recognition guidance under GAAP and is intended to improve and converge with international standards the financial reporting requirements for revenue recognition. The core principle of the new guidance is that an entity should recognize revenue to depict the transfer of control of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. New disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers are also required. Subsequently, the FASB issued several standards that clarified certain aspects of the standard but did not change the original standard. This new guidance is effective for the Company beginning in the first quarter of fiscal 2019. The ASU may be applied retrospectively (a) to each reporting period presented or (b) with the cumulative effect in retained earnings at the beginning of the adoption period. We currently anticipate adoption of the new standard effective October 1, 2018 using the modified retrospective method whereby the cumulative effect is recorded to retained earnings at the beginning of the adoption period. Adoption of the standard is dependent on completion of a detailed accounting assessment, the success of the design and implementation phase for changes to the Company's processes, internal controls and system functionality and the completion of our analysis of information necessary to assess the overall impact of adoption of this guidance on our consolidated financial statements. We continue to make progress on the accounting assessment and implementation phases to identify and implement the required changes to accounting policies and disclosures in our consolidated financial statements. We have reached preliminary conclusions on certain accounting assessments and we will continue to monitor and assess the impact of changes to the standard and interpretations as they become available. We expect revenue recognition related to our stand-alone product shipments and maintenance services to remain substantially unchanged. However, we continue to evaluate our preliminary conclusion and assess the impact on our other sources of revenue recognition.

Fresh Start Accounting (Tables)

Fresh Start Accounting (Tables)	3 Months Ended
	Dec. 31, 2017
Reorganizations [Abstract]
Schedule of Fresh-Start Adjustments	The adjustments set forth in the following consolidated balance sheet as of December 15, 2017 reflect the effect of the consummation of the transactions contemplated by the Plan of Reorganization (reflected in the column "Reorganization Adjustments") as well as fair value adjustments as a result of applying fresh start accounting (reflected in the column "Fresh Start Adjustments"). The explanatory notes highlight methods used to determine fair values or other amounts of the assets and liabilities, as well as significant assumptions or inputs. (In millions) Predecessor Company Reorganization Adjustments Fresh Start Adjustments Successor Company December 15, 2017 ASSETS Current assets: Cash and cash equivalents $ 744 $ (404 ) (1) $ — $ 340 Accounts receivable, net 523 — (106 ) (21,29) 417 Inventory 98 — 29 (22) 127 Other current assets 366 (58 ) (2) (66 ) (23) 242 TOTAL CURRENT ASSETS 1,731 (462 ) (143 ) 1,126 Property, plant and equipment, net 194 — 116 (24) 310 Deferred income taxes, net — 48 (3) (17 ) (25) 31 Intangible assets, net 298 — 3,137 (26) 3,435 Goodwill 3,541 — (909 ) (27) 2,632 Other assets 70 6 (4) (27 ) (28) 49 TOTAL ASSETS $ 5,834 $ (408 ) $ 2,157 $ 7,583 LIABILITIES Current liabilities: Debt maturing within one year $ 725 $ (696 ) (5) $ — $ 29 Accounts payable 325 (49 ) (6) — 276 Payroll and benefit obligations 123 23 (7) — 146 Deferred revenue 627 50 (8) (341 ) (29) 336 Business restructuring reserve 35 3 (9) — 38 Other current liabilities 97 65 (6,10) (3 ) (30) 159 TOTAL CURRENT LIABILITIES 1,932 (604 ) (344 ) 984 Non-current liabilities: Long-term debt, net of current portion — 2,771 (11) 96 (31) 2,867 Pension obligations 539 246 (12) — 785 Other post-retirement obligations — 212 (13) — 212 Deferred income taxes, net 28 113 (14) 548 (32) 689 Business restructuring reserve 26 4 (9) 4 (33) 34 Other liabilities 180 233 (8,15) (43 ) (29,34) 370 TOTAL NON-CURRENT LIABILITIES 773 3,579 605 4,957 LIABILITIES SUBJECT TO COMPROMISE 7,585 (7,585 ) (16) — — TOTAL LIABILITIES 10,290 (4,610 ) 261 5,941 Commitments and contingencies Equity awards on redeemable shares 6 (6 ) (17) — — Preferred stock: Series B 397 (397 ) (17) — — Series A 186 (186 ) (17) — — STOCKHOLDERS' (DEFICIT) EQUITY Common stock (Successor) — 1 (18) — 1 Additional paid-in capital (Successor) — 1,641 (18) — 1,641 Common stock (Predecessor) — — — — Additional paid-in capital (Predecessor) 2,387 (2,387 ) (17) — — (Accumulated deficit) retained earnings (5,978 ) 4,872 (19) 1,106 (36) — Accumulated other comprehensive (loss) income (1,454 ) 664 (20) 790 (35) — TOTAL STOCKHOLDERS' (DEFICIT) EQUITY (5,045 ) 4,791 1,896 1,642 TOTAL LIABILITIES AND STOCKHOLDERS' (DEFICIT) EQUITY $ 5,834 $ (408 ) $ 2,157 $ 7,583 Reorganization Adjustments In accordance with the Plan of Reorganization, the following adjustments were made: 1. Sources and Uses of Cash. The following reflects the net cash payments recorded as of the Emergence Date as a result of implementing the Plan of Reorganization: (In millions) Sources: Proceeds from Term Loan Credit Agreement, net of original issue discount $ 2,896 Release of restricted cash 76 Total sources of cash 2,972 Uses: Repayment of DIP Credit Agreement (725 ) Payment of DIP accrued interest (1 ) Cash paid to Predecessor first lien debt-holders (2,061 ) Cash paid to PBGC (340 ) Payment for professional fees escrow account (56 ) Funding payment for Avaya represented employee pension plan (49 ) Payment of accrued professional & administrative fees (27 ) Costs incurred for Term Loan Credit Agreement and ABL Credit Agreement (59 ) Payment for general unsecured claims (58 ) Total uses of cash (3,376 ) Net uses of cash $ (404 ) 2. Other Current Assets. (In millions) Release of restricted cash $ (76 ) Reclassification of prepaid debt issuance costs related to the Term Loan Credit Agreement (42 ) Payment of fees related to the ABL Credit Agreement 5 Restricted cash for bankruptcy related professional fees 55 Total other current assets $ (58 ) 3. Deferred Income Taxes. The adjustment represents the release of the valuation allowance on deferred tax assets for certain non-U.S. subsidiaries which management believes more likely than not will be realized as a result of the bankruptcy reorganization. 4. Other Assets. The adjustment represents the re-establishment of a foreign prepaid tax. 5. Debt Maturing Within One Year. The adjustment represents the net effect of the Company’s repayment of $725 million for the DIP Credit Agreement and Term Loan Credit Agreement principal payments of $29 million due over the next year. 6. Accounts Payable . The net decrease of $49 million includes $50 million for professional fees that were reclassified to Other current liabilities for accrued bankruptcy related professional fees that will be paid from an escrow account and the payment of $3 million of bankruptcy related professional fees, partially offset by reinstatement of $4 million contact cure costs from liabilities subject to compromise. 7. Payroll and Benefi t Obligations. The Company reinstated $23 million of liabilities subject to compromise related to the post-employment and post-retirement benefit obligations. 8. Deferred Revenue. The reinstatement of liabilities subject to compromise was $79 million of which $50 million is included in deferred revenue and $29 million in other liabilities. 9. Business Restructuring Reserve. The reinstatement of liabilities subject to compromise was $7 million , of which $3 million is current and $4 million is non-current. 10. Other Current Liabilities. (In millions) Reclassification of accrued bankruptcy related professional fees $ 50 Reinstatement of other current liabilities 16 Payment of accrued interest on the DIP Credit Agreement (1 ) Total other current liabilities $ 65 11. Exit Financing. In accordance with the Plan of Reorganization, the Company entered into the Term Loan Credit Agreement with a principal amount of $2,925 million maturing seven years from the date of issuance, and the ABL Credit Agreement, which allows borrowings up to an aggregate principal amount of $300 million , subject to borrowing base availability, maturing five years from the date of issuance. (In millions) Term Loan Credit Agreement $ 2,925 Less: Discount (29 ) Upfront and underwriting fees (54 ) Cash received upon emergence from bankruptcy 2,842 Reclassification of debt issuance cost incurred prior to emergence from bankruptcy (42 ) Current portion of Long-term debt (29 ) Long-term debt, net of current portion $ 2,771 12. Pension Obligations. In accordance with the Plan of Reorganization, the Company reinstated from liabilities subject to compromise $295 million related to the Avaya Pension Plan for represented employees and also contributed $49 million to the related pension trust. 13. Other Post-retirement Obligations. Other post-retirement benefit obligations of $212 million were reinstated from liabilities subject to compromise. 14. Deferred Income Taxes . The adjustment represents the reinstatement of the deferred tax liability that was included in liabilities subject to compromise. 15. Other Liabilities . The increase of $233 million primarily relates to the reinstatement of employee benefits, tax liabilities and deferred revenue from liabilities subject to compromise. Also included is the value of the Warrants issued to the holders of the Predecessor second lien obligations on the Emergence Date. 16. Liabilities Subject to Compromise. Liabilities subject to compromise were reinstated or settled as follows in accordance with the Plan of Reorganization: (In millions) Liabilities subject to compromise $ 7,585 Less amounts settled per the Plan of Reorganization Pre-petition first lien debt (4,281 ) Pre-petition second lien debt (1,440 ) Avaya Pension Plan for Salaried Employees (620 ) Amounts reinstated: Accounts payable (4 ) Payroll and benefit obligations (23 ) Deferred revenue (50 ) Business restructuring reserves (7 ) Other current liabilities (16 ) Pension obligations (295 ) Other post-retirement obligations (212 ) Deferred income taxes, net (118 ) Other liabilities (216 ) Total liabilities reinstated at emergence (941 ) General unsecured credit claims (1) (303 ) Liabilities subject to compromise $ — (1) In settlement of allowed general unsecured claims, each claimant will receive a pro-rata distribution of $58 million of the general unsecured claims account. The following table displays the detail on the gain on settlement of liabilities subject to compromise: (In millions) Pre-petition first lien debt $ 734 Pre-petition second lien debt 1,357 Avaya pension plan for salaried employees (514 ) General unsecured creditors' claims 227 Net gain on settlement of Liabilities subject to compromise $ 1,804 17. Cancellation of Predecessor Preferred and Common Stock. All common stock, Series A and B preferred stock and all other equity awards of the Predecessor Company were cancelled on the Emergence Date without any recovery on account thereof. 18. Issuance of Successor Common Stock and Warrants. In settlement of the Company's $5,721 million Predecessor first lien obligations and Predecessor second lien obligations, the holders of the Predecessor first lien obligations received a total of 99.3 million shares of common stock (fair value of $1,486 million ) and $2,061 million in cash and the holders of the Predecessor second lien obligations received a total of 4.4 million shares of common stock (fair value of $66 million ) and 5.6 million of Warrants to purchase additional common shares (fair value of $17 million ). In addition, as part of the Plan of Reorganization, the Company completed a distressed termination of the APPSE in accordance with the Stipulation Settlement with the PBGC, the PBGC received $340 million in cash and 6.1 million shares of common stock (fair value of $90 million ). 19. Accumulated Deficit. (In millions) Accumulated deficit: Net gain on settlement of liabilities subject to compromise $ 1,804 Expense for certain professional fees (26 ) Benefit from income taxes 118 Cancellation of Predecessor equity awards 6 Cancellation of Predecessor Preferred stock Series B 397 Cancellation of Predecessor Preferred stock Series A 186 Cancellation of Predecessor Common stock 2,387 Total $ 4,872 20. Accumulated Comprehensive Loss. The changes to Accumulated comprehensive loss relate to the settlement of the APPSE and the Avaya Supplemental Pension Plan ("ASPP") and the associated taxes. Fresh Start Adjustments At the Emergence Date, the Company met the requirements under ASC 852 for fresh start accounting as (i) the holders of existing voting shares of the Predecessor Company received less than 50% of the voting shares of the emerging entity and (ii) the reorganization value of the Company's assets immediately prior to confirmation was less than the post-petition liabilities and allowed claims. These adjustments reflect actual amounts recorded as of the Emergence Date. 21. Accounts Receivable. This adjustment relates to a change in accounting policy for the way the Company will present uncollected deferred revenue upon emergence from bankruptcy. The Company will offset such deferred revenue against the related account receivable. 22. Inventory . This adjustment relates to the write-up of inventory to fair value based on estimated selling prices, less costs of disposal. 23. Other Current Assets . This adjustment reflects the write-off of certain prepaid commissions, deferred installation costs and debt issuance costs that do not meet the definition of an asset upon emergence. 24. Property, Plant and Equipment . An adjustment of $116 million was recorded to increase the net book value of property, plant and equipment to its estimated fair value based on estimated current acquisition price, plus costs to make the property fully operational. The following table reflects the components of property, plant and equipment, net as of December 15, 2017 : (In millions) Buildings and improvements $ 82 Machinery and equipment 38 Rental equipment 85 Assets under construction 13 Internal use software 92 Total property, plant and equipment 310 Less: accumulated depreciation and amortization — Property, plant and equipment, net $ 310 25. Deferred Income Tax. T he adjustment represents the release of the valuation allowance on deferred tax assets for certain non-U.S. subsidiaries which management believes more likely than not will be realized as a result of future taxable income from the reversal of deferred tax liabilities that were established as part of fresh start accounting. 26. Intangible Assets. The Company recorded an adjustment to intangible assets for $3,137 million as follows: (In millions) Successor Predecessor December 15, 2017 Post-emergence December 15, 2017 Pre-emergence Difference Customer relationships and other intangible assets $ 2,155 $ 96 $ 2,059 Technology and patents 905 12 893 Trademarks and trade names 375 190 185 Total $ 3,435 $ 298 $ 3,137 The fair value of customer relationships was determined using the excess earnings method, a derivation of the income approach that calculates residual profit attributable to an asset after proper returns are paid to complementary or contributory assets. The fair value of technology and patents and trademarks and trade names determined using the royalty savings method, a derivation of the income approach that estimates the royalties saved through ownership of the assets. 27. Goodwill. Predecessor goodwill of $3,541 million was eliminated and Successor goodwill of $2,632 million was established based on the calculated reorganization value. (In millions) Reorganization value of Successor Company $ 7,583 Less: Fair value of Successor Company assets (4,951 ) Reorganization value of Successor Company assets in excess of fair value - goodwill $ 2,632 28. Other Assets. The $27 million decrease to other assets is related to prepaid commissions that do not meet the definition of an asset upon emergence as there is no future benefit to the Successor Company. 29. Deferred Revenue. The fair value of deferred revenue, which principally relates to payments on annual maintenance contracts, was determined by deducting selling costs and associated profit from the Predecessor deferred revenue balance to arrive at the costs and profit associated with fulfilling the liability. Additionally, the decrease includes the impact of an accounting policy change whereby the Successor Company no longer presents uncollected deferred revenue. 30. Other Current Liabilities. The decrease of $3 million to other current liabilities is related to the fair value of real estate leases determined to be above or below market using the income approach based on the difference between the contractual rental rate and the estimated market rental rate, discounted utilizing a risk-related discount rate. 31. Long-term Debt . The fair value of the Term Loan Credit Agreement was determined based on a market approach utilizing market-clearing data on the valuation date in addition to bid/ask prices. 32. Deferred Income Taxes. The adjustment represents the establishment of deferred tax liabilities related to book/tax differences created by fresh start accounting adjustments. The amount is net of the release of the valuation allowance on deferred tax assets, which management believes more likely than not will be realized as a result of future taxable income from the reversal of such deferred tax liabilities. 33. Business Restructuring Reserve. The Company recorded an increase to its non-current business restructuring reserves based on estimated future cash flows applied to a current discount rate at emergence. 34. Other Liabilities. A decrease in other liabilities of $43 million relates to deferred revenue and real estate leases as previously discussed. 35. Accumulated Other Comprehensive Loss. The remaining balance in Accumulated comprehensive loss was reversed to Reorganization expenses, net. 36. Fresh Start Adjustments. The following table reflects the cumulative impact of the fresh start adjustments as discussed above, the elimination of the Predecessor Company's accumulated other comprehensive loss and the adjustments required to eliminate accumulated deficit. (In millions) Eliminate Predecessor Intangible assets $ (298 ) Eliminate Predecessor Goodwill (3,541 ) Establish Successor Intangible assets 3,435 Establish Successor Goodwill 2,632 Fair value adjustment to Inventory 29 Fair value adjustment to Other current assets (66 ) Fair value adjustment to Property, plant and equipment 116 Fair value adjustment to Other assets (27 ) Fair value adjustment to Deferred revenue 235 Fair value adjustment to Business restructuring reserves (4 ) Fair value adjustment to Other current liabilities 3 Fair value adjustment to Long-term debt (96 ) Fair value adjustment to Other liabilities 43 Release Predecessor Accumulated comprehensive loss (790 ) Fresh start adjustments included in Reorganization items, net $ 1,671 Tax impact of fresh start adjustments (565 ) Gain on fresh start accounting $ 1,106

Goodwill And Intangible Assets

Goodwill And Intangible Assets (Tables)	3 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The carrying value of goodwill by operating segments for the periods indicated was as follows: (In millions) Global Communications Solutions Avaya Global Services Total September 30, 2017 (Predecessor) $ 1,093 $ 2,449 $ 3,542 Adjustments (1 ) — (1 ) Impact of fresh start accounting 68 (977 ) (909 ) December 15, 2017 (Predecessor) $ 1,160 $ 1,472 $ 2,632 December 31, 2017 (Successor) $ 1,160 $ 1,472 $ 2,632
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets by Major Class	The gross carrying amount and accumulated amortization by major intangible asset category as of December 31, 2017 (Successor) and September 30, 2017 (Predecessor) were as follows: Successor As of December 31, 2017 (In millions) Technology and patents Customer relationships and other intangibles Trademarks Total Gross Carrying Amount $ 905 $ 2,155 $ 375 $ 3,435 Accumulated Amortization (7 ) (7 ) — (14 ) Net $ 898 $ 2,148 $ 375 $ 3,421 Predecessor As of September 30, 2017 (In millions) Technology and patents Customer relationships and other intangibles Trademarks Total Gross Carrying Amount $ 1,427 $ 2,196 $ 545 $ 4,168 Accumulated Amortization (1,411 ) (2,091 ) — (3,502 ) Accumulated Impairment — — (355 ) (355 ) Net $ 16 $ 105 $ 190 $ 311
Schedule of Future Amortization Expense	Future amortization expense related to intangible assets as of December 31, 2017 are as follows: (In millions) Remainder of fiscal 2018 $ 247 2019 326 2020 326 2021 325 2022 298 2023 and thereafter 1,566 Total $ 3,088

Supplementary Financial Infor34

Supplementary Financial Information (Tables)	3 Months Ended
	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Schedule of Additional Financial Information	A summary of other (expense) income, net for the periods indicated is presented in the following table: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 OTHER (EXPENSE) INCOME, NET Interest income $ — $ 2 $ — Foreign currency gains, net 2 — 11 Income from transition services agreement, net — 3 — Other pension and post-retirement benefit costs 1 (8 ) (6 ) Change in fair value of the warrant liability (5 ) — — Other, net — 1 (1 ) Total other (expense) income, net $ (2 ) $ (2 ) $ 4 A summary of reorganization items, net for the periods indicated is presented in the following table: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 REORGANIZATION ITEMS, NET Bankruptcy-related professional fees $ — $ (56 ) $ — Net gain on settlement of liabilities subject to compromise — 1,804 — Net gain on fresh start adjustments — 1,671 — Other items, net — (3 ) — Reorganization items, net $ — $ 3,416 $ — Cash payments for reorganization items $ 1 $ 2,524 $ —

Business Restructuring Reserv35

Business Restructuring Reserves And Programs (Tables)	3 Months Ended
	Dec. 31, 2017
Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Schedule of Restructuring and Related Costs	The following table summarizes the components of the fiscal 2018 restructuring program for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor): (In millions) Employee Separation Costs Lease Obligations Total 2018 restructuring charges $ 12 $ — $ 12 Cash payments (3 ) — (3 ) Balance as of December 15, 2017 (Predecessor) $ 9 $ — $ 9 2018 restructuring charges (1) $ — $ 10 $ 10 Cash payments (2 ) (10 ) (12 ) Balance as of December 31, 2017 (Successor) $ 7 $ — $ 7 (1) Charges incurred in connection with the termination of the Santa Clara lease.
Fiscal 2017 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Schedule of Restructuring and Related Costs	The following table summarizes the components of the fiscal 2017 restructuring program for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor): (In millions) Employee Separation Costs Lease Obligations Total Balance as of September 30, 2017 (Predecessor) $ 4 $ 1 $ 5 Cash payments (1 ) (1 ) (2 ) Balance as of December 15, 2017 (Predecessor) $ 3 $ — $ 3 Balance as of December 31, 2017 (Successor) $ 3 $ — $ 3
Fiscal 2008-2016 Restructuring Programs
Restructuring Cost and Reserve [Line Items]
Schedule of Restructuring and Related Costs	The following table aggregates the components of the fiscal 2008 through 2016 restructuring programs for the period from December 16, 2017 through December 31, 2017 (Successor) and the period from October 1, 2017 through December 15, 2017 (Predecessor): (In millions) Employee Separation Costs Lease Obligations Total Balance as of September 30, 2017 (Predecessor) $ 51 $ 24 $ 75 Cash payments (3 ) (17 ) (20 ) Expense 1 1 2 Adjustments - fresh start and reorganization items $ 4 $ (1 ) $ 3 Balance as of December 15, 2017 (Predecessor) $ 53 $ 7 $ 60 Cash Payments (2 ) — (2 ) Impact of foreign currency fluctuations 2 — 2 Balance as of December 31, 2017 (Successor) $ 53 $ 7 $ 60

Financing Arrangements (Tables)

Financing Arrangements (Tables)	3 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table reflects principal amounts of debt and debt net of discounts and issuance costs as of December 31, 2017 (Successor) and principal amounts of debt and debt net of discounts and issuance costs as of September 30, 2017 (Predecessor) , which includes the impact of adequate protection payments and accrued interest as of January 19, 2017: Successor Predecessor December 31, 2017 September 30, 2017 (In millions) Principal amount Net of discounts and issuance costs Principal amount Net of discounts and issuance costs Term Loan Credit Agreement $ 2,925 $ 2,896 $ — $ — DIP Credit Agreement due January 19, 2018 — — 725 725 First lien debt: Senior secured term B-3 loans — — 594 594 Senior secured term B-4 loans — — 1 1 Senior secured term B-6 loans — — 519 519 Senior secured term B-7 loans — — 2,012 2,012 7% senior secured notes — — 982 982 9% senior secured notes — — 284 284 Second lien debt: 10.50% senior secured notes — — 1,440 1,440 Total debt $ 2,925 2,896 $ 6,557 6,557 Debt maturing within one year (29 ) (725 ) Long-term debt, net of current portion (1) $ 2,867 $ 5,832 (1) Pre-petition long-term debt as of September 30, 2017 (Predecessor) was included in liabilities subject to compromise.

Derivative Warrant Liability (T

Derivative Warrant Liability (Tables)	3 Months Ended
	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Schedule of Assumptions Used	December 31, 2017 December 15, 2017 Expected volatility 52.38 % 54.57 % Risk free interest rates 2.20 % 2.20 % Expected life (in years) 4.96 5.00 Price per share of common stock $17.55 $14.93 Fair value of warrant liability $22 million $17 million

Fair Value Measures (Tables)

Fair Value Measures (Tables)	3 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis as of December 31, 2017 (Successor) and September 30, 2017 (Predecessor) were as follows: Successor December 31, 2017 Fair Value Measurements Using (In millions) Total Level 1 Level 2 Level 3 Other Non-Current Assets: Investments $ 1 $ 1 $ — $ — Other Non-Current Liabilities: Warrants $ 22 $ — $ — $ 22 Predecessor September 30, 2017 Fair Value Measurements Using (In millions) Total Level 1 Level 2 Level 3 Other Non-Current Assets: Investments $ 1 $ 1 $ — $ —
Carry Values and Estimated Fair Value of Debt Instruments	The estimated fair values of the amounts borrowed under the Company’s financing agreements at December 31, 2017 (Successor) and September 30, 2017 (Predecessor) are as follows: Successor Predecessor December 31, 2017 September 30, 2017 (In millions) Principal Amount Fair Value Principal Amount Fair Value Term Loan Credit Agreement due December 15, 2024 $ 2,925 $ 2,896 $ — $ — DIP Credit Agreement due January 19, 2018 — — 725 732 Variable rate Term B-3 Loans due October 26, 2017 — — 594 503 Variable rate Term B-4 Loans due October 26, 2017 — — 1 1 Variable rate Term B-6 Loans due March 31, 2018 — — 519 440 Variable rate Term B-7 Loans due May 29, 2020 — — 2,012 1,709 7% senior secured notes due April 1, 2019 — — 982 832 9% senior secured notes due April 1, 2019 — — 284 241 10.50% senior secured notes due March 1, 2021 — — 1,440 67 Total $ 2,925 $ 2,896 $ 6,557 $ 4,525

Benefit Obligations (Tables)

Benefit Obligations (Tables)	3 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of Net Benefit Costs	The components of the pension and post-retirement net periodic benefit cost (credit) for the periods indicated are provided in the tables below: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Pension Benefits - U.S. Components of Net Periodic Benefit Cost Service cost $ — $ 1 $ 1 Interest cost 1 22 24 Expected return on plan assets (2 ) (38 ) (45 ) Amortization of previously unrecognized net actuarial loss — 20 26 Settlement loss (1) — — — Net periodic benefit cost $ (1 ) $ 5 $ 6 (1) Excludes Plan of Reorganization related settlements discussed below that were recorded in Reorganization items, net in the Condensed Consolidated Statements of Operations. Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Pension Benefits - Non-U.S. Components of Net Periodic Benefit Cost Service cost $ — $ 2 $ 2 Interest cost — 3 2 Amortization of previously unrecognized net actuarial loss — 1 3 Net periodic benefit cost $ — $ 6 $ 7 Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Post-retirement Benefits - U.S. Components of Net Periodic Benefit Cost Interest cost $ — $ 3 $ 3 Expected return on plan assets — (2 ) (2 ) Amortization of unrecognized prior service cost — (3 ) (4 ) Amortization of previously unrecognized net actuarial loss — 2 3 Curtailment — — (4 ) Net periodic benefit cost $ — $ — $ (4 )

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The fair value of the premium-priced stock options granted on the Emergence Date was determined using a lattice option pricing model with the following assumptions: Exercise price $ 19.46 Expected term (in years) (1) 8.54 Volatility (2) 65.37 % Risk-free rate (3) 2.35 % Dividend yield (4) — % ( 1) Expected term based on the vesting terms of the option and a contractual life of ten years . (2) Volatility based on peer group companies adjusted for the Company's leverage. (3) Risk-free rate based on U.S. Treasury yields with a term equal to the expected option term. (4) Dividend yield was assumed to be zero as the Company does not anticipate paying dividends.

Earnings (Loss) Per Common Sh41

Earnings (Loss) Per Common Share (Tables)	3 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	The following table sets forth the calculation of net income attributable to common shareholders and the computation of basic and diluted earnings (loss) per share for the periods indicated: Successor Predecessor (In millions, except per share amounts) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Net income (loss) per share: Numerator Net income (loss) $ 237 $ 2,977 $ (103 ) Dividends to preferred stockholders — (6 ) (8 ) Undistributed earnings 237 2,971 (111 ) Percentage allocated to common stockholders (1) 100.0 % 86.9 % 100.0 % Numerator for basic and diluted earnings per common share $ 237 $ 2,582 $ (111 ) Denominator Denominator for basic earnings per weighted average common shares 109.8 497.3 497.0 Effect of dilutive securities Restricted stock units 0.5 — — Stock options — — — Warrants — — — Denominator for diluted earnings per weighted average common shares 110.3 497.3 497.0 Per common share net income (loss) Basic $ 2.16 $ 5.19 $ (0.22 ) Diluted $ 2.15 $ 5.19 $ (0.22 ) (1) Basic weighted average common stock outstanding 109.8 497.3 497.0 Basic weighted average common stock and common stock equivalents (preferred shares) 109.8 572.4 497.0 Percentage allocated to common stockholders 100.0 % 86.9 % 100.0 %

Operating Segments (Tables)

Operating Segments (Tables)	3 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Summarized financial information relating to the Company’s operating segments is shown in the following table for the periods indicated: Successor Predecessor (In millions) Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 REVENUE Global Communications Solutions $ 71 $ 253 $ 343 Avaya Networking (1) — — 58 Enterprise Collaboration Solutions 71 253 401 Avaya Global Services 77 351 474 $ 148 $ 604 $ 875 GROSS PROFIT Global Communications Solutions $ 41 $ 169 $ 231 Avaya Networking (1) — — 25 Enterprise Collaboration Solutions 41 169 256 Avaya Global Services 50 196 284 Unallocated Amounts (2) (13 ) (3 ) (5 ) 78 362 535 OPERATING EXPENSES Selling, general and administrative 50 264 336 Research and development 9 38 62 Amortization of intangible assets 7 10 57 Restructuring charges, net 10 14 10 76 326 465 OPERATING INCOME 2 36 70 INTEREST EXPENSE, OTHER (EXPENSE) INCOME, NET AND REORGANIZATION ITEMS, NET (11 ) 3,400 (170 ) (LOSS) INCOME BEFORE INCOME TAXES $ (9 ) $ 3,436 $ (100 ) (1) The Networking business was sold on July 14, 2017. (2) Unallocated Amounts in Gross Profit include the effect of the amortization of technology intangibles and costs that are not core to the measurement of segment management’s performance, but rather are controlled at the corporate level.

Accumulated Other Comprehensi43

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Components of Accumulated Other Comprehensive Income (Loss)	The components of accumulated other comprehensive income (loss) for the periods indicated are summarized as follows: (In millions) Change in unamortized pension, post-retirement and postemployment benefit-related items Foreign Currency Translation Other Accumulated Other Comprehensive Income (Loss) Beginning balance September 30, 2016 (Predecessor) $ (1,627 ) $ (33 ) $ (1 ) $ (1,661 ) Other comprehensive income before reclassifications — 19 — 19 Amounts reclassified to earnings 20 — — 20 (Provision for) benefit from income taxes (6 ) 4 — (2 ) Ending balance December 31, 2016 (Predecessor) $ (1,613 ) $ (10 ) $ (1 ) $ (1,624 ) (In millions) Change in unamortized pension, post-retirement and postemployment benefit-related items Foreign Currency Translation Other Accumulated Other Comprehensive Income (Loss) Beginning balance October 1, 2017 (Predecessor) $ (1,375 ) $ (72 ) $ (1 ) $ (1,448 ) Other comprehensive (loss) income before reclassifications (24 ) 3 — (21 ) Amounts reclassified to earnings 16 — — 16 Pension settlement 721 — — 721 Provision for income taxes (58 ) — — (58 ) Ending balance December 15, 2017 (Predecessor) (720 ) (69 ) (1 ) (790 ) Elimination of Predecessor Company accumulated other comprehensive loss 720 69 1 790 Ending balance December 15, 2017 (Predecessor) $ — $ — $ — $ — Beginning balance December 15, 2017 (Successor) $ — $ — $ — $ — Other comprehensive loss before reclassifications — (13 ) — (13 ) Ending balance December 31, 2017 (Successor) $ — $ (13 ) $ — $ (13 )

Commitments And Contingencies (

Commitments And Contingencies (Tables)	3 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Product Warranty Liability	The Company periodically reviews the adequacy of its product warranties and adjusts, if necessary, the warranty percentage and accrued warranty reserve, which is included in other current and non-current liabilities in the Condensed Consolidated Balance Sheets, for actual experience. (In millions) Accrued warranty obligations as of September 30, 2017 (Predecessor) $ 2 Reductions for payments and costs to satisfy claims (1 ) Accruals for warranties issued during the period 1 Accrued warranty obligations as of December 15, 2017 (Predecessor) $ 2 Reductions for payments and costs to satisfy claims $ (1 ) Accruals for warranties issued during the period 1 Accrued warranty obligations as of December 31, 2017 (Successor) $ 2

Condensed Financial Informati45

Condensed Financial Information of Parent Company (Tables)	3 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Balance Sheet	Avaya Holdings Corp. Parent Company Only Condensed Balance Sheets (unaudited) (In millions) Successor Predecessor December 31, 2017 September 30, 2017 ASSETS Investment in Avaya Inc. $ 1,867 $ — TOTAL ASSETS $ 1,867 $ — LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT) LIABILITIES Deficit in excess of investment in Avaya Inc. $ — $ 4,429 TOTAL LIABILITIES — 4,429 Commitments and contingencies Predecessor equity awards on redeemable shares — 7 Preferred stock, Series B — 393 Preferred stock, Series A — 184 TOTAL STOCKHOLDERS' EQUITY (DEFICIT) 1,867 (5,013 ) TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT) $ 1,867 $ —
Condensed Income Statement	Avaya Holdings Corp. Parent Company Only Condensed Statements of Operations (unaudited) (In millions, except per share amounts) Successor Predecessor Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Equity in net income (loss) of Avaya Inc. $ 237 $ 2,977 $ (103 ) NET INCOME (LOSS) $ 237 $ 2,977 $ (103 ) NET INCOME (LOSS) PER SHARE AVAILABLE TO COMMON STOCKHOLDERS Basic $ 2.16 $ 5.19 $ (0.22 ) Diluted $ 2.15 $ 5.19 $ (0.22 ) Weighted average shares outstanding Basic 109.8 497.3 497.0 Diluted 110.3 497.3 497.0
Condensed Statement of Comprehensive Income	Avaya Holdings Corp. Parent Company Only Condensed Statements of Comprehensive Income (Loss) (unaudited) (In millions) Successor Predecessor Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three months ended December 31, 2016 Net income (loss) $ 237 $ 2,977 $ (103 ) Equity in other comprehensive (loss) income of Avaya Inc. (13 ) 658 37 Elimination of Predecessor Company accumulated other comprehensive loss — 790 — Comprehensive income (loss) $ 224 $ 4,425 $ (66 )
Condensed Cash Flow Statement	Avaya Holdings Corp. Parent Company Only Condensed Statements of Cash Flows (unaudited) (In millions) Successor Predecessor Period from December 16, 2017 through December 31, 2017 Period from October 1, 2017 through December 15, 2017 Three Months Ended December 31, 2016 Net income (loss) $ 237 $ 2,977 $ (103 ) Adjustments to reconcile net loss to net cash used for operating activities: Equity in net income (loss) of Avaya Inc. (237 ) (2,977 ) 103 Net cash provided by (used for) operating activities — — — Net cash provided by (used for) investing activities — — — Net cash provided by (used for) financing activities — — — Net increase (decrease) in cash and cash equivalents — — — Cash and cash equivalents at beginning of period — — — Cash and cash equivalents at end of period $ — $ — $ —

Background and Basis Of Prese46

Background and Basis Of Presentation (Details)	Jul. 14, 2017segment	Jul. 13, 2017Segments	Dec. 31, 2017segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	2	3	2

Accounting Policy Changes (Deta

Accounting Policy Changes (Details) $ in Millions	Dec. 31, 2017USD ($)
Accounting Policies [Abstract]
Deferred revenue	$ 100

Recent Accounting Pronounceme48

Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other pension and post-retirement benefit costs	$ 1
Predecessor
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other pension and post-retirement benefit costs		$ (8)	$ (6)
other income (expense)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other pension and post-retirement benefit costs	$ 1
other income (expense) | Predecessor
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other pension and post-retirement benefit costs		$ (8)
Accounting Standards Update 2017-07 | other income (expense) | Predecessor
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other pension and post-retirement benefit costs			$ (6)

Emergence from Voluntary Reor49

Emergence from Voluntary Reorganization under Chapter 11 Proceedings (Details) - USD ($)	Dec. 15, 2017	Dec. 31, 2017	Jul. 31, 2017
Fresh-Start Adjustment [Line Items]
Repayment of DIP financing	$ 725,000,000	$ 0
Shares authorized (in shares)	605,000,000
Preferred stock, shares authorized	55,000,000	55,000,000
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	550,000,000	550,000,000
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares issued		110,000,000
Debt face amount		$ 2,925,000,000
Class of warrant or right, number of securities called by each warrant or right (in Shares)	5,600,000
Class of warrant or right, exercise price of warrants or rights (USD per share)	$ 25.55
Payment to PBGC		0
Common stock issued for GUC (in shares)	200,000
Payment of unsecured claims		0
Transition services agreement			2 years
General Unsecured Creditor Reserve
Fresh-Start Adjustment [Line Items]
Payment of unsecured claims	$ 58,000,000
Term Loan
Fresh-Start Adjustment [Line Items]
Debt face amount		2,925,000,000
First Lien Debt
Fresh-Start Adjustment [Line Items]
Common stock issued for debt (in shares)	99,300,000
Repayments of long-term Debt	$ 2,061,000,000
Second Lien Debt
Fresh-Start Adjustment [Line Items]
Common stock issued for debt (in shares)	4,400,000
Term Loan Credit Agreement | Term Loan
Fresh-Start Adjustment [Line Items]
Debt face amount	$ 2,925,000,000
7% senior secured notes | First Lien Debt
Fresh-Start Adjustment [Line Items]
Debt face amount		$ 0
Interest rate, stated percentage		7.00%
9% senior secured notes | First Lien Debt
Fresh-Start Adjustment [Line Items]
Debt face amount		$ 0
Interest rate, stated percentage		9.00%
10.50% senior secured notes | Second Lien Debt
Fresh-Start Adjustment [Line Items]
Debt face amount		$ 0
Interest rate, stated percentage		10.50%
Revolving Credit Facility | ABL Credit Agreement | Line of Credit
Fresh-Start Adjustment [Line Items]
Line of credit facility, current borrowing capacity	$ 300,000,000
Avaya Inc. Pension Plan for Salaried Employees
Fresh-Start Adjustment [Line Items]
Common stock issued for PBGC (in shares)	6,100,000
Payment to PBGC	$ 340,000,000

Fresh Start Accounting - Narrat

Fresh Start Accounting - Narrative (Details) - USD ($) shares in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 5,721,000,000		$ 5,721,000,000
Repayment of DIP financing	725,000,000	$ 0
Debt maturing within one year	(29,000,000)	(29,000,000)	$ (29,000,000)	$ (29,000,000)
Debt face amount		2,925,000,000		2,925,000,000
Funding payment for Avaya represented employee pension plan		0
Debt cancelled due to bankruptcy	$ 5,721,000,000
Class of warrant or right, number of securities called by each warrant or right (in Shares)	5.6		5.6
Payment to PBGC		0
Establish Successor Goodwill	$ 2,632,000,000		$ 2,632,000,000
Discharge of Debt
Fresh-Start Adjustment [Line Items]
Adjustments, accounts payable	(49,000,000)		(49,000,000)
Adjustments, accounts payable, reclassification of accrued bankruptcy related professional fees	(50,000,000)		(50,000,000)
Adjustments, accounts payable, payment of bankruptcy professional fees	(3,000,000)		(3,000,000)
Adjustments, accounts payable, reinstatement of contract cure costs	4,000,000		4,000,000
Adjustments, payroll and benefit obligations	23,000,000		23,000,000
Fair value adjustment to Deferred revenue	79,000,000		79,000,000
Adjustments, deferred revenue	50,000,000		50,000,000
Adjustments, other liabilities, deferred revenue	29,000,000		29,000,000
Adjustments, restructuring reserve	7,000,000		7,000,000
Adjustments, business restructuring reserve	3,000,000		3,000,000
Adjustments, business restructuring reserve	4,000,000		4,000,000
Adjustments, liabilities subject to compromise, pension obligation	(295,000,000)		(295,000,000)
Funding payment for Avaya represented employee pension plan	(49,000,000)
Adjustments, other post-retirement obligation	212,000,000		212,000,000
Adjustments, other liabilities	233,000,000		233,000,000
Payment to PBGC	340,000,000
Adjustments, other assets	6,000,000		6,000,000
Adjustments, other current liabilities	65,000,000		65,000,000
Revaluation of Assets
Fresh-Start Adjustment [Line Items]
Adjustments, property, plant and equipment	116,000,000		116,000,000
Adjustments, intangible assets, net	3,137,000,000		3,137,000,000
Adjustments, other assets	(27,000,000)		(27,000,000)
Revaluation of Liabilities
Fresh-Start Adjustment [Line Items]
Fair value adjustment to Deferred revenue	(235,000,000)		(235,000,000)
Adjustments, deferred revenue	(341,000,000)		(341,000,000)
Adjustments, business restructuring reserve	4,000,000		4,000,000
Adjustments, other liabilities	(43,000,000)		(43,000,000)
Adjustments, other current liabilities	(3,000,000)		(3,000,000)
Minimum
Fresh-Start Adjustment [Line Items]
Enterprise value	5,100,000,000		5,100,000,000
Maximum
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 7,100,000,000		7,100,000,000
Term Loan
Fresh-Start Adjustment [Line Items]
Debt face amount		2,925,000,000		2,925,000,000
First Lien Debt
Fresh-Start Adjustment [Line Items]
Debt cancelled due to bankruptcy				4,281,000,000
Common stock issued for debt (in shares)	99.3
Common stock issued for Predecessor debt	$ 1,486,000,000
Repayment of long-term debt	$ 2,061,000,000
Second Lien Debt
Fresh-Start Adjustment [Line Items]
Debt cancelled due to bankruptcy				1,440,000,000
Common stock issued for debt (in shares)	4.4
Common stock issued for Predecessor debt	$ 66,000,000
Term Loan Credit Agreement | Term Loan
Fresh-Start Adjustment [Line Items]
Debt face amount	$ 2,925,000,000		2,925,000,000
Debt term	7 years
Revolving Credit Facility | ABL Credit Agreement | Line of Credit
Fresh-Start Adjustment [Line Items]
Debt term	5 years
Line of credit facility, current borrowing capacity	$ 300,000,000		$ 300,000,000
Letter of Credit | ABL Credit Agreement | Line of Credit
Fresh-Start Adjustment [Line Items]
Letters of credit outstanding		74,000,000		74,000,000
Avaya Inc. Pension Plan for Salaried Employees
Fresh-Start Adjustment [Line Items]
Payment to PBGC	$ 340,000,000
Common stock issued for PBGC (in shares)	6.1		6.1
Common stock issued for Pension Benefit Guaranty Corporation	$ 90,000,000		$ 90,000,000
Predecessor
Fresh-Start Adjustment [Line Items]
Repayment of DIP financing			725,000,000		$ 0
Debt maturing within one year						$ (725,000,000)
Debt face amount						6,557,000,000
Funding payment for Avaya represented employee pension plan			(49,000,000)		0
Payment to PBGC			340,000,000		$ 0
Common stock issued for Pension Benefit Guaranty Corporation	90,000,000		90,000,000
Goodwill	3,541,000,000		3,541,000,000
Predecessor | Term Loan
Fresh-Start Adjustment [Line Items]
Debt face amount						$ 0
Warrants
Fresh-Start Adjustment [Line Items]
Fair value of warrant liability	$ 17,000,000	$ 22,000,000	$ 17,000,000	$ 22,000,000

Fresh Start Accounting - Enterp

Fresh Start Accounting - Enterprise Value To The Estimated Fair Value Of The Successor Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2017	Dec. 15, 2017
Fresh-Start Adjustment [Line Items]
Enterprise value		$ 5,721
Cash and cash equivalents		340
Minimum cash required for operations		(120)
Fair value of Term Loan Credit Agreement		(2,896)
Fair value of capitalized leases		(20)
Fair value of pension and other post-retirement obligations, net of tax		(856)
Change in net deferred tax liabilities from reorganization		(510)
Fair value of Successor warrants		(17)
Fair value of Successor common stock		$ 1,642
Shares issued at December 15, 2017 (in shares)	110,000,000
Per share value (usd per share)		$ 14.93
Debt, fair value, percent of par		99.00%
Other Postretirement Benefits Plan
Fresh-Start Adjustment [Line Items]
Rate of return on plan assets		5.90%
Discount rate		3.77%
UNITED STATES | Pension Plan
Fresh-Start Adjustment [Line Items]
Rate of return on plan assets		7.75%
Discount rate		3.70%
Foreign Plan | Pension Plan
Fresh-Start Adjustment [Line Items]
Rate of return on plan assets		3.80%
Discount rate		1.52%

Fresh Start Accounting - Ente52

Fresh Start Accounting - Enterprise Value To The Estimated Reorganization Value (Details) $ in Millions	Dec. 15, 2017USD ($)
Reorganizations [Abstract]
Enterprise value	$ 5,721
Plus:
Non-debt current liabilities	955
Non-debt non-current liabilities	2,090
Excess cash and cash equivalents	220
Less:
Fair value of pension and other post-retirement obligations, net of tax	(856)
Fair value of capitalized leases	(20)
Change in net deferred tax liabilities from reorganization	(510)
Fair value of Successor warrants	(17)
Reorganization value of Successor assets	$ 7,583

Fresh Start Accounting - Fresh

Fresh Start Accounting - Fresh Start Accounting - Balance Sheet (Details) $ in Millions	Dec. 15, 2017USD ($)
Postconfirmation, Current Assets [Abstract]
Cash and cash equivalents	$ 340
Accounts receivable, net	417
Inventory	127
Other current assets	242
TOTAL CURRENT ASSETS	1,126
Property, plant and equipment, net	310
Deferred income taxes, net	31
Intangible assets, net	3,435
Establish Successor Goodwill	2,632
Other assets	49
Reorganization value of Successor Company	7,583
Postconfirmation, Current Liabilities [Abstract]
Debt maturing within one year	29
Postconfirmation, Accounts Payable	276
Payroll and benefit obligations	146
Deferred revenue	336
Business restructuring reserve	38
Other current liabilities	159
TOTAL CURRENT LIABILITIES	984
Long-term debt, net of current portion	2,867
Pension obligations	785
Other post-retirement obligations	212
Deferred income taxes, net	689
Business restructuring reserve	34
Other liabilities	370
TOTAL NON-CURRENT LIABILITIES	4,957
TOTAL LIABILITIES	5,941
Postconfirmation, Stockholders' Equity [Abstract]
Common stock (Successor)	1
Additional paid-in capital (Successor)	1,641
TOTAL STOCKHOLDERS' (DEFICIT) EQUITY	1,642
TOTAL LIABILITIES AND STOCKHOLDERS' (DEFICIT) EQUITY	7,583
Discharge of Debt
Fresh-Start Adjustment, Increase (Decrease), Current Assets [Abstract]
Adjustments, cash and cash equivalents	(404)
Adjustments, other current assets	(58)
Adjustments, Total Current Assets	(462)
Adjustments, deferred income taxes, net	48
Adjustments, other assets	6
Adjustments, Total Assets	(408)
Fresh-Start Adjustment, Increase (Decrease), Current Liabilities [Abstract]
Adjustments, debt maturing within one year	(696)
Adjustments, accounts payable	(49)
Adjustments, payroll and benefit obligations	23
Adjustments, deferred revenue	50
Adjustments, business restructuring reserve	3
Adjustments, other current liabilities	65
Adjustments, Total Current Liabilities	(604)
Adjustments, long-term debt, net of current portion	2,771
Adjustments, pension obligations	246
Adjustments, other post-retirement obligation	212
Adjustments, deferred revenue	113
Adjustments, business restructuring reserve	4
Adjustments, other liabilities	233
Adjustments, Total Non-Current Liabilities	3,579
Adjustments, Liabilities Subject To Compromise	(7,585)
Adjustments, Total Liabilities	(4,610)
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity [Abstract]
Adjustments, equity awards on redeemable shares	(6)
Adjustments, common stock	1
Adjustments, additional paid-in capital	1,641
Adjustments, (Accumulated deficit) retained earnings	4,872
Adjustments, accumulated other comprehensive (loss) income	664
Adjustments, Total Stockholders' Equity	4,791
Adjustments, Total Liabilities and Stockholders' (Deficit) Equity	(408)
Revaluation of Assets
Fresh-Start Adjustment, Increase (Decrease), Current Assets [Abstract]
Adjustments, accounts receivable, net	(106)
Adjustments, inventory	29
Adjustments, other current assets	(66)
Adjustments, Total Current Assets	(143)
Adjustments, property, plant and equipment	116
Adjustments, deferred income taxes, net	(17)
Adjustments, intangible assets, net	3,137
Adjustments, goodwill	(909)
Adjustments, other assets	(27)
Adjustments, Total Assets	2,157
Revaluation of Liabilities
Fresh-Start Adjustment, Increase (Decrease), Current Liabilities [Abstract]
Adjustments, deferred revenue	(341)
Adjustments, other current liabilities	(3)
Adjustments, Total Current Liabilities	(344)
Adjustments, long-term debt, net of current portion	96
Adjustments, deferred revenue	548
Adjustments, business restructuring reserve	4
Adjustments, other liabilities	(43)
Adjustments, Total Non-Current Liabilities	605
Adjustments, Total Liabilities	261
Exchange of Stock for Stock
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity [Abstract]
Adjustments, (Accumulated deficit) retained earnings	1,106
Adjustments, accumulated other comprehensive (loss) income	790
Adjustments, Total Stockholders' Equity	1,896
Adjustments, Total Liabilities and Stockholders' (Deficit) Equity	2,157
Predecessor
Preconfirmation, Current Assets [Abstract]
Cash and cash equivalents	744
Accounts receivable, net	523
Inventory	98
Other current assets	366
TOTAL CURRENT ASSETS	1,731
Property, plant and equipment, net	194
Deferred income taxes, net	0
Intangible assets, net	298
Goodwill	3,541
Other assets	70
TOTAL ASSETS	5,834
Preconfirmation, Current Liabilities [Abstract]
Debt maturing within one year	725
Accounts payable	325
Payroll and benefit obligations	123
Deferred revenue	627
Business restructuring reserve	35
Other current liabilities	97
TOTAL CURRENT LIABILITIES	1,932
Pension obligations	539
Other post-retirement obligations	0
Deferred income taxes, net	28
Business restructuring reserve	26
Other liabilities	180
TOTAL NON-CURRENT LIABILITIES	773
LIABILITIES SUBJECT TO COMPROMISE	7,585
TOTAL LIABILITIES	10,290
Equity awards on redeemable shares	6
Preconfirmation, Stockholders' Equity [Abstract]
Additional paid-in capital (Predecessor)	2,387
(Accumulated deficit) retained earnings	(5,978)
Accumulated other comprehensive (loss) income	(1,454)
TOTAL STOCKHOLDERS' (DEFICIT) EQUITY	(5,045)
TOTAL LIABILITIES AND STOCKHOLDERS' (DEFICIT) EQUITY	5,834
Fresh-Start Adjustment, Increase (Decrease), Current Assets [Abstract]
Adjustments, goodwill	(909)
Predecessor | Discharge of Debt
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity [Abstract]
Adjustments, additional paid-in capital	(2,387)
Series B preferred stock | Discharge of Debt
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity [Abstract]
Adjustments, preferred stock	(397)
Series B preferred stock | Predecessor
Preconfirmation, Current Liabilities [Abstract]
Preferred stock	397
Series A preferred stock | Discharge of Debt
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity [Abstract]
Adjustments, preferred stock	(186)
Series A preferred stock | Predecessor
Preconfirmation, Current Liabilities [Abstract]
Preferred stock	$ 186

Fresh Start Accounting - Source

Fresh Start Accounting - Sources And Uses Of Cash (Details) - USD ($) $ in Millions	Dec. 15, 2017	Dec. 31, 2017
Uses:
Cash paid to PBGC		$ 0
Funding payment for Avaya represented employee pension plan		0
Payment for general unsecured claims		$ 0
Discharge of Debt
Sources:
Proceeds from Term Loan Credit Agreement, net of original issue discount	$ 2,896
Release of restricted cash	76
Total sources of cash	2,972
Uses:
Repayment of DIP Credit Agreement	(725)
Payment of DIP accrued interest	(1)
Cash paid to Predecessor first lien debt-holders	(2,061)
Cash paid to PBGC	(340)
Payment for professional fees escrow account	(56)
Funding payment for Avaya represented employee pension plan	(49)
Payment of accrued professional & administrative fees	(27)
Costs incurred for Term Loan Credit Agreement and ABL Credit Agreement	(59)
Payment for general unsecured claims	(58)
Total uses of cash	(3,376)
Net uses of cash	$ (404)

Fresh Start Accounting - Other

Fresh Start Accounting - Other Current Assets (Details) - Discharge of Debt $ in Millions	Dec. 15, 2017USD ($)
Fresh-Start Adjustment [Line Items]
Restricted cash	$ (76)
Reclassification of prepaid debt issuance costs related to the Term Loan Credit Agreement	(42)
Payment of fees related to the ABL Credit Agreement	5
Restricted cash for bankruptcy related professional fees	55
Total other current assets	$ (58)

Fresh Start Accounting - Othe56

Fresh Start Accounting - Other Current Liabilities (Details) - Discharge of Debt $ in Millions	Dec. 15, 2017USD ($)
Fresh-Start Adjustment [Line Items]
Reclassification of accrued bankruptcy related professional fees	$ 50
Reinstatement of other current liabilities	16
Payment of accrued interest on the DIP Credit Agreement	(1)
Total other current liabilities	$ 65

Fresh Start Accounting - Exit F

Fresh Start Accounting - Exit Financing (Details) - USD ($)	Dec. 31, 2017	Dec. 15, 2017
Fresh-Start Adjustment [Line Items]
Debt face amount	$ 2,925,000,000
Debt, Current	(29,000,000)	$ (29,000,000)
Discharge of Debt
Fresh-Start Adjustment [Line Items]
Discount		(29,000,000)
Upfront and underwriting fees		(54,000,000)
Cash received upon emergence from bankruptcy		2,842,000,000
Reclassification of debt issuance cost incurred prior to emergence from bankruptcy		(42,000,000)
Long-term debt, net of current portion		2,771,000,000
Term Loan
Fresh-Start Adjustment [Line Items]
Debt face amount	$ 2,925,000,000
Term Loan | Term Loan Credit Agreement
Fresh-Start Adjustment [Line Items]
Debt face amount		$ 2,925,000,000

Fresh Start Accounting - Liabil

Fresh Start Accounting - Liabilities Subject to Compromise (Details) - USD ($) $ in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Amounts reinstated:
Liabilities subject to compromise	$ 0		$ 0
Payment of unsecured claims		$ 0
Gain On Settlement of Liabilities Subject To Compromise [Abstract]
Net gain on settlement of liabilities subject to compromise		$ 0
Discharge of Debt
Less amounts settled per the Plan of Reorganization
Pre-petition first lien debt	(4,281)		(4,281)
Pre-petition second lien debt	(1,440)		(1,440)
Avaya Pension Plan for Salaried Employees	(620)		(620)
Amounts reinstated:
Accounts payable	(4)		(4)
Payroll and benefit obligations	(23)		(23)
Deferred revenue	(50)		(50)
Business restructuring reserves	(7)		(7)
Other current liabilities	(16)		(16)
Pension obligations	(295)		(295)
Other post-retirement obligations	(212)		(212)
Deferred income taxes, net	(118)		(118)
Other liabilities	(216)		(216)
Total liabilities reinstated at emergence	(941)		(941)
General unsecured credit claims	(303)		(303)
Payment of unsecured claims	58
Predecessor
Fresh-Start Adjustment [Line Items]
Liabilities subject to compromise	7,585		7,585
Amounts reinstated:
Payment of unsecured claims			58	$ 0
Gain On Settlement of Liabilities Subject To Compromise [Abstract]
Pre-petition first lien debt			734
Pre-petition second lien debt			1,357
Avaya pension plan for salaried employees			(514)
General unsecured creditors' claims			227
Net gain on settlement of liabilities subject to compromise			$ 1,804	$ 0
General Unsecured Creditor Reserve
Amounts reinstated:
Payment of unsecured claims	$ 58

Fresh Start Accounting - Accumu

Fresh Start Accounting - Accumulated Deficit (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Fresh-Start Adjustment [Line Items]
Net gain on settlement of liabilities subject to compromise	$ 0
Discharge of Debt
Fresh-Start Adjustment [Line Items]
Expense for certain professional fees		$ (26)
Benefit from income taxes		118
Cancellation of Predecessor equity awards		6
Cancellation of Predecessor Common stock		2,387
Total		4,872
Series B preferred stock | Discharge of Debt
Fresh-Start Adjustment [Line Items]
Cancellation of Predecessor Preferred stock		397
Series A preferred stock | Discharge of Debt
Fresh-Start Adjustment [Line Items]
Cancellation of Predecessor Preferred stock		186
Predecessor
Fresh-Start Adjustment [Line Items]
Net gain on settlement of liabilities subject to compromise		$ 1,804	$ 0

Fresh Start Accounting - Proper

Fresh Start Accounting - Property, Plant and Equipment (Details) $ in Millions	Dec. 15, 2017USD ($)
Fresh-Start Adjustment [Line Items]
Total property, plant and equipment	$ 310
Less: accumulated depreciation and amortization	0
Property, plant and equipment, net	310
Buildings and improvements
Fresh-Start Adjustment [Line Items]
Total property, plant and equipment	82
Machinery and equipment
Fresh-Start Adjustment [Line Items]
Total property, plant and equipment	38
Rental equipment
Fresh-Start Adjustment [Line Items]
Total property, plant and equipment	85
Assets under construction
Fresh-Start Adjustment [Line Items]
Total property, plant and equipment	13
Internal use software
Fresh-Start Adjustment [Line Items]
Total property, plant and equipment	$ 92

Fresh Start Accounting - Intang

Fresh Start Accounting - Intangible Assets (Details) $ in Millions	Dec. 15, 2017USD ($)
Fresh-Start Adjustment [Line Items]
Establish Successor Intangible assets	$ 3,435
Revaluation of Assets
Fresh-Start Adjustment [Line Items]
Adjustments, intangible assets, net	3,137
Predecessor
Fresh-Start Adjustment [Line Items]
Intangible assets, net	298
Customer relationships and other intangibles
Fresh-Start Adjustment [Line Items]
Establish Successor Intangible assets	2,155
Customer relationships and other intangibles | Revaluation of Assets
Fresh-Start Adjustment [Line Items]
Adjustments, intangible assets, net	2,059
Customer relationships and other intangibles | Predecessor
Fresh-Start Adjustment [Line Items]
Intangible assets, net	96
Technology and patents
Fresh-Start Adjustment [Line Items]
Establish Successor Intangible assets	905
Technology and patents | Revaluation of Assets
Fresh-Start Adjustment [Line Items]
Adjustments, intangible assets, net	893
Technology and patents | Predecessor
Fresh-Start Adjustment [Line Items]
Intangible assets, net	12
Trademarks and trade names | Trademarks and trade names
Fresh-Start Adjustment [Line Items]
Establish Successor Intangible assets	375
Trademarks and trade names | Trademarks and trade names | Revaluation of Assets
Fresh-Start Adjustment [Line Items]
Adjustments, intangible assets, net	185
Trademarks and trade names | Trademarks and trade names | Predecessor
Fresh-Start Adjustment [Line Items]
Intangible assets, net	$ 190

Fresh Start Accounting - Goodwi

Fresh Start Accounting - Goodwill (Details) $ in Millions	Dec. 15, 2017USD ($)
Reorganizations [Abstract]
Reorganization value of Successor Company	$ 7,583
Less: Fair value of Successor Company assets	(4,951)
Reorganization value of Successor Company assets in excess of fair value - goodwill	$ 2,632

Fresh Start Accounting - Fres63

Fresh Start Accounting - Fresh Start Adjustments (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Fresh-Start Adjustment [Line Items]
Establish Successor Intangible assets		$ 3,435
Establish Successor Goodwill		2,632
Fresh start adjustments included in Reorganization items, net	$ 0
Revaluation of Assets
Fresh-Start Adjustment [Line Items]
Fair value adjustment to Inventory		29
Fair value adjustment to Other current assets		(66)
Fair value adjustment to Property, plant and equipment		116
Fair value adjustment to Other assets		(27)
Revaluation of Liabilities
Fresh-Start Adjustment [Line Items]
Fair value adjustment to Deferred revenue		235
Fair value adjustment to Business restructuring reserves		(4)
Fair value adjustment to Other current liabilities		3
Fair value adjustment to Long-term debt		(96)
Fair value adjustment to Other liabilities		43
Exchange of Stock for Stock
Fresh-Start Adjustment [Line Items]
Release Predecessor Accumulated comprehensive loss		(790)
Predecessor
Fresh-Start Adjustment [Line Items]
Eliminate Predecessor Intangible assets		(298)
Eliminate Predecessor Goodwill		(3,541)
Fresh start adjustments included in Reorganization items, net		1,671	$ 0
Tax impact of fresh start adjustments		(565)
Gain on fresh start accounting		$ 1,106

Goodwill And Intangible Asset64

Goodwill And Intangible Assets - Goodwill (Details) - USD ($) $ in Millions	2 Months Ended
	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017
Goodwill [Roll Forward]
Goodwill, end		$ 2,632
Global Communications Solutions
Goodwill [Roll Forward]
Goodwill, end		1,160
Avaya Global Services
Goodwill [Roll Forward]
Goodwill, end		$ 1,472
Predecessor
Goodwill [Roll Forward]
Goodwill, start	$ 3,542
Adjustments	(1)
Impact of fresh start accounting			$ (909)
Goodwill, end	2,632
Goodwill, end	3,542		2,632
Predecessor | Global Communications Solutions
Goodwill [Roll Forward]
Goodwill, start	1,093
Adjustments	(1)
Impact of fresh start accounting			68
Goodwill, end	1,160
Goodwill, end	1,093		1,160
Predecessor | Avaya Global Services
Goodwill [Roll Forward]
Goodwill, start	2,449
Adjustments	0
Impact of fresh start accounting			(977)
Goodwill, end	1,472
Goodwill, end	$ 2,449		$ 1,472

Goodwill And Intangible Asset65

Goodwill And Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount	$ 3,435		$ 3,435
Accumulated Amortization	(14)		(14)
Net	3,421		3,421
Amortization of intangible assets	14
Technology and patents
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount	905		905
Accumulated Amortization	(7)		(7)
Net	898		$ 898
Finite-lived intangible asset, useful life			5 years 8 months 12 days
Customer relationships and other intangibles
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount	2,155		$ 2,155
Accumulated Amortization	(7)		(7)
Net	2,148		$ 2,148
Finite-lived intangible asset, useful life			14 years 6 months
Trademarks and trade names | Trademarks and trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount	375		$ 375
Accumulated Amortization	0		0
Net	$ 375		$ 375
Minimum
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			3 years
Minimum | Technology and patents
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			3 years
Minimum | Customer relationships and other intangibles
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			7 years
Maximum
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			20 years
Maximum | Technology and patents
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			10 years
Maximum | Customer relationships and other intangibles
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			20 years
Maximum | Trademarks and trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Finite-lived intangible asset, useful life			10 years
Predecessor
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount					$ 4,168
Accumulated Amortization					(3,502)
Accumulated Impairment					(355)
Net					311
Amortization of intangible assets		$ 13		$ 62
Predecessor | Technology and patents
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount					1,427
Accumulated Amortization					(1,411)
Accumulated Impairment					0
Net					16
Predecessor | Customer relationships and other intangibles
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount					2,196
Accumulated Amortization					(2,091)
Accumulated Impairment					0
Net					105
Predecessor | Trademarks and trade names | Trademarks and trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Roll Forward]
Gross Carrying Amount					545
Accumulated Amortization					0
Accumulated Impairment					(355)
Net					$ 190

Goodwill And Intangible Asset66

Goodwill And Intangible Assets - Amortization Expense (Details) $ in Millions	Dec. 31, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of fiscal 2018	$ 247
2,019	326
2,020	326
2,021	325
2,022	298
2023 and thereafter	1,566
Total	$ 3,088

Supplementary Financial Infor67

Supplementary Financial Information (Other (Expense) Income, Net) (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
OTHER INCOME (EXPENSE), NET
Interest income	$ 0
Foreign currency gains, net	2
Income from transition services agreement, net	0
Other pension and post-retirement benefit costs	1
Change in fair value of the warrant liability	(5.2)
Other, net	0
Total other (expense) income, net	$ (2)
Predecessor
OTHER INCOME (EXPENSE), NET
Interest income		$ 2	$ 0
Foreign currency gains, net		0	11
Income from transition services agreement, net		3	0
Other pension and post-retirement benefit costs		(8)	(6)
Change in fair value of the warrant liability		0	0
Other, net		1	(1)
Total other (expense) income, net		$ (2)	$ 4

Supplementary Financial Infor68

Supplementary Financial Information (Reorganization Items) (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Supplementary Financial Information [Line Items]
Bankruptcy-related professional fees	$ 0
Net gain on settlement of liabilities subject to compromise	0
Net gain on fresh start adjustments	0
Other items, net	0
Reorganization items, net	0
Cash payments for reorganization items	$ 1
Predecessor
Supplementary Financial Information [Line Items]
Bankruptcy-related professional fees		$ (56)	$ 0
Net gain on settlement of liabilities subject to compromise		1,804	0
Net gain on fresh start adjustments		1,671	0
Other items, net		(3)	0
Reorganization items, net		3,416	0
Cash payments for reorganization items		$ 2,524	$ 0

Supplementary Financial Infor69

Supplementary Financial Information (Narrative) (Details) - Predecessor $ in Millions	2 Months Ended
	Dec. 15, 2017USD ($)
Supplementary Financial Information [Line Items]
Payments for liabilities subject to compromise	$ 2,468
Payments for emergence and success fees	$ 56

Business Restructuring Reserv70

Business Restructuring Reserves And Programs - Restructuring Reserve (Details) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017USD ($)	Dec. 15, 2017USD ($)	Dec. 31, 2017USD ($)employee	Dec. 31, 2016USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 10
Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges	10
Workforce reduction | employee			206
Restructuring Reserve [Roll Forward]
Cash payments	(12)
Ending balance	7		$ 7
Fiscal 2017 Restructuring Program
Restructuring Reserve [Roll Forward]
Ending balance	3		3
Fiscal 2008-2016 Restructuring Programs
Restructuring Reserve [Roll Forward]
Cash payments	(2)
Impact of foreign currency fluctuations	2
Ending balance	60		60
Employee Separation Costs | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0
Restructuring Reserve [Roll Forward]
Cash payments	(2)
Ending balance	7		7
Employee Separation Costs | Fiscal 2017 Restructuring Program
Restructuring Reserve [Roll Forward]
Ending balance	3		3
Employee Separation Costs | Fiscal 2008-2016 Restructuring Programs
Restructuring Reserve [Roll Forward]
Cash payments	(2)
Impact of foreign currency fluctuations	2
Ending balance	53		53
Lease Obligations | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges	10
Restructuring Reserve [Roll Forward]
Cash payments	(10)
Ending balance	0		0
Lease Obligations | Fiscal 2017 Restructuring Program
Restructuring Reserve [Roll Forward]
Ending balance	0		0
Lease Obligations | Fiscal 2008-2016 Restructuring Programs
Restructuring Reserve [Roll Forward]
Cash payments	0
Impact of foreign currency fluctuations	0
Ending balance	7		7
Predecessor
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 14		$ 10
Predecessor | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges		12
Restructuring Reserve [Roll Forward]
Beginning balance	9
Cash payments		(3)
Ending balance		9
Predecessor | Fiscal 2017 Restructuring Program
Restructuring Reserve [Roll Forward]
Beginning balance	3	5	5
Cash payments		(2)
Ending balance		3
Predecessor | Fiscal 2008-2016 Restructuring Programs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		2
Restructuring Reserve [Roll Forward]
Beginning balance	60	75	75
Cash payments		(20)
Ending balance		60
Predecessor | Employee Separation Costs | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges		12
Restructuring Reserve [Roll Forward]
Beginning balance	9
Cash payments		(3)
Ending balance		9
Predecessor | Employee Separation Costs | Fiscal 2017 Restructuring Program
Restructuring Reserve [Roll Forward]
Beginning balance	3	4	4
Cash payments		(1)
Ending balance		3
Predecessor | Employee Separation Costs | Fiscal 2008-2016 Restructuring Programs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1
Restructuring Reserve [Roll Forward]
Beginning balance	53	51	51
Cash payments		(3)
Ending balance		53
Predecessor | Lease Obligations | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0
Restructuring Reserve [Roll Forward]
Beginning balance	0
Cash payments		0
Ending balance		0
Predecessor | Lease Obligations | Fiscal 2017 Restructuring Program
Restructuring Reserve [Roll Forward]
Beginning balance	0	1	1
Cash payments		(1)
Ending balance		0
Predecessor | Lease Obligations | Fiscal 2008-2016 Restructuring Programs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1
Restructuring Reserve [Roll Forward]
Beginning balance	7	24	$ 24
Cash payments		(17)
Ending balance		$ 7
Successor | Fiscal 2008-2016 Restructuring Programs
Restructuring Reserve [Roll Forward]
Adjustments - fresh start and reorganization items	3
Successor | Employee Separation Costs | Fiscal 2008-2016 Restructuring Programs
Restructuring Reserve [Roll Forward]
Adjustments - fresh start and reorganization items	4
Successor | Lease Obligations | Fiscal 2008-2016 Restructuring Programs
Restructuring Reserve [Roll Forward]
Adjustments - fresh start and reorganization items	$ (1)
UNITED STATES | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Workforce reduction | employee			120
EMEA [Member] | Fiscal 2018 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Workforce reduction | employee			25

Financing Arrangements - Schedu

Financing Arrangements - Schedule of Debt (Details) - USD ($)	Dec. 31, 2017	Dec. 15, 2017	Sep. 30, 2017
Debt Instrument [Line Items]
Principal amount	$ 2,925,000,000
Net of discounts and issuance costs	2,896,000,000
Debt maturing within one year	(29,000,000)	$ (29,000,000)
Long-term debt, net of current portion	2,867,000,000
Term Loan
Debt Instrument [Line Items]
Principal amount	2,925,000,000
Net of discounts and issuance costs	2,896,000,000
DIP Credit Agreement
Debt Instrument [Line Items]
Principal amount	0
Net of discounts and issuance costs	0
First Lien Debt | Senior secured term B-3 loans
Debt Instrument [Line Items]
Principal amount	0
Net of discounts and issuance costs	0
First Lien Debt | Senior secured term B-4 loans
Debt Instrument [Line Items]
Principal amount	0
Net of discounts and issuance costs	0
First Lien Debt | Senior secured term B-6 loans
Debt Instrument [Line Items]
Principal amount	0
Net of discounts and issuance costs	0
First Lien Debt | Senior secured term B-7 loans
Debt Instrument [Line Items]
Principal amount	0
Net of discounts and issuance costs	$ 0
First Lien Debt | 7% senior secured notes
Debt Instrument [Line Items]
Interest rate, stated percentage	7.00%
Principal amount	$ 0
Net of discounts and issuance costs	$ 0
First Lien Debt | 9% senior secured notes
Debt Instrument [Line Items]
Interest rate, stated percentage	9.00%
Principal amount	$ 0
Net of discounts and issuance costs	$ 0
Second Lien Debt | 10.50% senior secured notes
Debt Instrument [Line Items]
Interest rate, stated percentage	10.50%
Principal amount	$ 0
Net of discounts and issuance costs	$ 0
Predecessor
Debt Instrument [Line Items]
Principal amount			$ 6,557,000,000
Net of discounts and issuance costs			6,557,000,000
Debt maturing within one year			(725,000,000)
Long-term debt, net of current portion			0
Predecessor | Senior secured term B-3 loans
Debt Instrument [Line Items]
Principal amount			594,000,000
Net of discounts and issuance costs			594,000,000
Predecessor | Senior secured term B-4 loans
Debt Instrument [Line Items]
Principal amount			1,000,000
Net of discounts and issuance costs			1,000,000
Predecessor | Senior secured term B-6 loans
Debt Instrument [Line Items]
Principal amount			519,000,000
Net of discounts and issuance costs			519,000,000
Predecessor | Senior secured term B-7 loans
Debt Instrument [Line Items]
Principal amount			2,012,000,000
Net of discounts and issuance costs			2,012,000,000
Predecessor | 7% senior secured notes
Debt Instrument [Line Items]
Principal amount			982,000,000
Net of discounts and issuance costs			982,000,000
Predecessor | 9% senior secured notes
Debt Instrument [Line Items]
Principal amount			284,000,000
Net of discounts and issuance costs			284,000,000
Predecessor | 10.50% senior secured notes
Debt Instrument [Line Items]
Principal amount			1,440,000,000
Net of discounts and issuance costs			1,440,000,000
Predecessor | Term Loan
Debt Instrument [Line Items]
Principal amount			0
Net of discounts and issuance costs			0
Predecessor | DIP Credit Agreement
Debt Instrument [Line Items]
Principal amount			725,000,000
Net of discounts and issuance costs			725,000,000
Liabilities Subject To Compromise | Predecessor
Debt Instrument [Line Items]
Long-term debt, net of current portion			$ 5,832,000,000

Financing Arrangements - Narrat

Financing Arrangements - Narrative (Details)	Dec. 15, 2017USD ($)	Jan. 19, 2017USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)
Debt Instrument [Line Items]
Debt cancelled due to bankruptcy	$ 5,721,000,000
Debt face amount			$ 2,925,000,000
Weighted average contractual interest rate of debt			6.20%
Capital lease obligations			$ 22,000,000
Affiliated Entity
Debt Instrument [Line Items]
Capital lease obligations			21,000,000
Predecessor
Debt Instrument [Line Items]
Debt face amount				$ 6,557,000,000
Capital lease obligations				14,000,000
Liabilities subject to compromise, capital lease obligations and accrued interest				12,000,000
Predecessor | Affiliated Entity
Debt Instrument [Line Items]
Capital lease obligations				24,000,000
Liabilities subject to compromise, capital lease obligations and accrued interest				10,000,000
First Lien Debt
Debt Instrument [Line Items]
Fair value of assets received by debt holders	3,547,000,000
Debt cancelled due to bankruptcy			4,281,000,000
Second Lien Debt
Debt Instrument [Line Items]
Fair value of assets received by debt holders	83,000,000
Debt cancelled due to bankruptcy			1,440,000,000
Term Loan
Debt Instrument [Line Items]
Debt face amount			2,925,000,000
Term Loan | Predecessor
Debt Instrument [Line Items]
Debt face amount				0
Term Loan | Term Loan Credit Agreement
Debt Instrument [Line Items]
Debt face amount	$ 2,925,000,000
Term Loan | Revolving Credit Facility | ABR Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	3.75%
Term Loan | Revolving Credit Facility | ABR Loans | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Term Loan | Revolving Credit Facility | LIBOR Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	4.75%
Term Loan | Revolving Credit Facility | LIBOR Loans | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Line of Credit | Revolving Credit Facility | ABL Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity	$ 300,000,000
Minimum fixed charge coverage ratio	1
Minimum net borrowing availability	$ 25,000,000
Percent of total borrowing base	10.00%
Line of Credit | Revolving Credit Facility | Base Rate Loans
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | Base Rate Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	0.75%
Line of Credit | Revolving Credit Facility | Base Rate Loans | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Line of Credit | Revolving Credit Facility | LIBOR Loans Denominated In US Dollars
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | LIBOR Loans Denominated In US Dollars | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	1.75%
Line of Credit | Revolving Credit Facility | Canadian Prime Rate Loans
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | Canadian Prime Rate Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	0.75%
Line of Credit | Revolving Credit Facility | CDOR Loans
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | CDOR Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	1.75%
Line of Credit | Revolving Credit Facility | LIBOR Loans Denominated In Sterling
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | LIBOR Loans Denominated In Sterling | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	1.75%
Line of Credit | Revolving Credit Facility | EURIBOR Loans Denominated In Euro
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | EURIBOR Loans Denominated In Euro | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	1.75%
Line of Credit | Revolving Credit Facility | Overnight LIBOR Loans
Debt Instrument [Line Items]
Step up or step down percentage	0.25%
Line of Credit | Revolving Credit Facility | Overnight LIBOR Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage	1.75%
Line of Credit | Letter of Credit | ABL Credit Agreement
Debt Instrument [Line Items]
Letters of credit, maximum amount	$ 150,000,000
Letters of credit outstanding			74,000,000
Letter of credit, remaining borrowing capacity			139,000,000
DIP Credit Agreement
Debt Instrument [Line Items]
Debt face amount			$ 0
DIP Credit Agreement | Predecessor
Debt Instrument [Line Items]
Debt face amount				$ 725,000,000
DIP Credit Agreement | Base Rate Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		6.50%
DIP Credit Agreement | Base Rate Loans | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%
DIP Credit Agreement | Base Rate Loans | Eurocurrency Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		2.00%
DIP Credit Agreement | DIP Credit Agreement | Predecessor
Debt Instrument [Line Items]
Principal amount		$ 725,000,000
Letters of credit outstanding		$ 150,000,000
Cash collateralization percent, US dollar		101.50%
Cash collateralization percent, alternative currencies		103.00%
DIP Credit Agreement | Eurocurrency Loans | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		7.50%
DIP Credit Agreement | Eurocurrency Loans | Eurocurrency Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%

Derivative Warrant Liability -

Derivative Warrant Liability - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Dec. 15, 2017	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Class of warrant or right, number of securities called by each warrant or right (in Shares)	5.6
Class of warrant or right, exercise price of warrants or rights (USD per share)	$ 25.55
Fair value adjustment of warrants		$ 5.2
Warrants
Class of Warrant or Right [Line Items]
Expected life (in years)	5 years	4 years 11 months 16 days

Derivative Warrant Liability 74

Derivative Warrant Liability - Assumptions Used (Details) - Warrants - USD ($) $ / shares in Units, $ in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017
Class of Warrant or Right [Line Items]
Volatility		52.38%	54.57%
Risk-free rate		2.20%	2.20%
Expected life (in years)	5 years	4 years 11 months 16 days
Stock price (USD per share)	$ 14.93	$ 17.55	$ 14.93
Fair value of warrant liability	$ 17	$ 22	$ 17

Fair Value Measures (Assets and

Fair Value Measures (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - Recurring - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 1
Warrants	22
Quoted prices in active markets for identical instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1
Warrants	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0
Warrants	0
Unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0
Warrants	$ 22
Predecessor
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		$ 1
Predecessor | Quoted prices in active markets for identical instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		1
Predecessor | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
Predecessor | Unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		$ 0

Fair Value Measures (Fair Value

Fair Value Measures (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017
Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 2,925
Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	2,896
Term Loan | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	2,925
Term Loan | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	2,896
DIP Credit Agreement | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
DIP Credit Agreement | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-3 Loans due October 26, 2017 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-3 Loans due October 26, 2017 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-4 Loans due October 26, 2017 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-4 Loans due October 26, 2017 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-6 Loans due March 31, 2018 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-6 Loans due March 31, 2018 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-7 Loans due May 29, 2020 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	0
First Lien Debt | Variable rate Term B-7 Loans due May 29, 2020 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
First Lien Debt | 7% senior secured notes due April 1, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate, stated percentage	7.00%
First Lien Debt | 7% senior secured notes due April 1, 2019 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
First Lien Debt | 7% senior secured notes due April 1, 2019 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
First Lien Debt | 9% senior secured notes due April 1, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate, stated percentage	9.00%
First Lien Debt | 9% senior secured notes due April 1, 2019 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
First Lien Debt | 9% senior secured notes due April 1, 2019 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
Second Lien Debt | 10.50% senior secured notes due March 1, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate, stated percentage	10.50%
Second Lien Debt | 10.50% senior secured notes due March 1, 2021 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
Second Lien Debt | 10.50% senior secured notes due March 1, 2021 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 0
Predecessor | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		$ 6,557
Predecessor | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		4,525
Predecessor | Variable rate Term B-3 Loans due October 26, 2017 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		594
Predecessor | Variable rate Term B-4 Loans due October 26, 2017 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		1
Predecessor | Variable rate Term B-6 Loans due March 31, 2018 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		519
Predecessor | Variable rate Term B-7 Loans due May 29, 2020 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		2,012
Predecessor | 7% senior secured notes due April 1, 2019 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		982
Predecessor | 9% senior secured notes due April 1, 2019 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		284
Predecessor | 10.50% senior secured notes due March 1, 2021 | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		1,440
Predecessor | Term Loan | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		0
Predecessor | Term Loan | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		0
Predecessor | DIP Credit Agreement | Principal Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		725
Predecessor | DIP Credit Agreement | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		732
Predecessor | First Lien Debt | Variable rate Term B-3 Loans due October 26, 2017 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		503
Predecessor | First Lien Debt | Variable rate Term B-4 Loans due October 26, 2017 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		1
Predecessor | First Lien Debt | Variable rate Term B-6 Loans due March 31, 2018 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		440
Predecessor | First Lien Debt | Variable rate Term B-7 Loans due May 29, 2020 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		1,709
Predecessor | First Lien Debt | 7% senior secured notes due April 1, 2019 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		832
Predecessor | First Lien Debt | 9% senior secured notes due April 1, 2019 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		241
Predecessor | Second Lien Debt | 10.50% senior secured notes due March 1, 2021 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value		$ 67

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Sep. 30, 2018
Income Tax [Line Items]
Operating loss carryforward, estimated utilization in remainder of fiscal year	$ 196	$ 196
Tax cuts and jobs act, change in tax rate, DTL, income tax benefit	$ 245
Net Operating Loss And Tax Carryforwards And Other
Income Tax [Line Items]
Valuation allowance increase (decrease)		(787)
Deferred Tax Asset For Non-US Jurisdictions
Income Tax [Line Items]
Valuation allowance increase (decrease)		(47)
Fresh Start Accounting Adjustments
Income Tax [Line Items]
Valuation allowance increase (decrease)		$ (461)
Scenario, Forecast
Income Tax [Line Items]
Statutory tax rate			24.50%

Benefit Obligations - Schedule

Benefit Obligations - Schedule of Net Benefit Costs (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Components of Net Periodic Benefit Cost
Curtailment	$ 0
Predecessor
Components of Net Periodic Benefit Cost
Curtailment		$ 0	$ (4)
Other Postretirement Benefits Plan
Components of Net Periodic Benefit Cost
Interest cost	0
Expected return on plan assets	0
Amortization of unrecognized prior service cost	0
Amortization of previously unrecognized net actuarial loss	0
Curtailment	0
Net periodic benefit cost	0
Other Postretirement Benefits Plan | Predecessor
Components of Net Periodic Benefit Cost
Interest cost		3	3
Expected return on plan assets		(2)	(2)
Amortization of unrecognized prior service cost		(3)	(4)
Amortization of previously unrecognized net actuarial loss		2	3
Curtailment		0	(4)
Net periodic benefit cost		0	(4)
UNITED STATES | Pension Plan
Components of Net Periodic Benefit Cost
Service cost	0
Interest cost	1
Expected return on plan assets	(2)
Amortization of previously unrecognized net actuarial loss	0
Settlement loss(1)	0
Net periodic benefit cost	(1)
UNITED STATES | Pension Plan | Predecessor
Components of Net Periodic Benefit Cost
Service cost		1	1
Interest cost		22	24
Expected return on plan assets		(38)	(45)
Amortization of previously unrecognized net actuarial loss		20	26
Settlement loss(1)		0	0
Net periodic benefit cost		5	6
Foreign Plan | Pension Plan
Components of Net Periodic Benefit Cost
Service cost	0
Interest cost	0
Amortization of previously unrecognized net actuarial loss	0
Net periodic benefit cost	$ 0
Foreign Plan | Pension Plan | Predecessor
Components of Net Periodic Benefit Cost
Service cost		2	2
Interest cost		3	2
Amortization of previously unrecognized net actuarial loss		1	3
Net periodic benefit cost		$ 6	$ 7

Benefit Obligations - Narrative

Benefit Obligations - Narrative (Details) - USD ($) shares in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Payment to PBGC		$ 0
Gain on settlement		0
Expected future contributions to satisfy funding requirements, remainder of fiscal year		43,000,000
Avaya Inc. Pension Plan for Salaried Employees
Defined Benefit Plan Disclosure [Line Items]
Payment to PBGC	$ 340,000,000
Common stock issued for PBGC (in shares)	6.1		6.1
Common stock issued for Pension Benefit Guaranty Corporation	$ 90,000,000		$ 90,000,000
Plan termination increase (decrease) in benefit obligation	(2,192,000,000)
Plan termination increase (decrease) in plan assets	(1,573,000,000)
Loss on settlement recorded in Reorganization items, net	514,000,000
ASPP Plan
Defined Benefit Plan Disclosure [Line Items]
Plan termination increase (decrease) in benefit obligation	(88,000,000)
Gain on settlement	53,000,000
Settlement consideration	17,000,000
APP And Other
Defined Benefit Plan Disclosure [Line Items]
Plan termination increase (decrease) in benefit obligation	3,000,000
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)	49,000,000
Postemployment Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, remainder of fiscal year (less than $1 million)		12,000,000
Reimbursement for excess claims paid		(3,000,000)
HRA
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)		1,000,000
Domestic Plan [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions to satisfy minimum funding requirements		0
UNITED STATES | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)		1,000,000
Foreign Plan | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)		1,000,000
Expected future employer contributions, remainder of fiscal year (less than $1 million)		24,000,000
Predecessor
Defined Benefit Plan Disclosure [Line Items]
Payment to PBGC			340,000,000	$ 0
Common stock issued for Pension Benefit Guaranty Corporation	90,000,000		90,000,000
Loss on settlement recorded in Reorganization items, net			514,000,000
Pension settlement			721,000,000
Gain on settlement			1,804,000,000	$ 0
Predecessor | Postemployment Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)			2,000,000
Predecessor | HRA
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)			1,000,000
Predecessor | Domestic Plan [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions to satisfy minimum funding requirements			0
Predecessor | UNITED STATES | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)			1,000,000
Predecessor | Foreign Plan | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)			3,000,000
Maximum
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, remainder of fiscal year (less than $1 million)		$ 1,000,000
Maximum | Predecessor | Domestic Plan [Member] | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer (less than $1 million)			1,000,000
Change in unamortized pension, postretirement and postemployment benefit-related items | Avaya Inc. Pension Plan for Salaried Employees
Defined Benefit Plan Disclosure [Line Items]
Pension settlement	703,000,000
Change in unamortized pension, postretirement and postemployment benefit-related items | ASPP Plan
Defined Benefit Plan Disclosure [Line Items]
Pension settlement	$ 18,000,000
Change in unamortized pension, postretirement and postemployment benefit-related items | Predecessor
Defined Benefit Plan Disclosure [Line Items]
Pension settlement			$ 721,000,000

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) - USD ($) shares in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 1,000,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period				10 years
Predecessor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated compensation cost			$ 3,000,000
2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized (shares)		7.4		7.4
Number of shares available for grant (shares)		2.8		2.8
2017 Equity Incentive Plan | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted (shares)	3.4
Options granted (shares)	1.2
Director | 2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum award		$ 750,000		$ 750,000

Share-Based Compensation - Assu

Share-Based Compensation - Assumptions (Details)	1 Months Ended
	Dec. 31, 2017$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (USD per share)	$ 19.46
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	8 years 6 months 16 days
Volatility	65.37%
Risk-free rate	2.35%
Dividend yield	0.00%

Capital Stock (Details)

Capital Stock (Details) - $ / shares	Dec. 31, 2017	Dec. 15, 2017
Class of Stock [Line Items]
Preferred stock, shares authorized	55,000,000	55,000,000
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, shares issued	0
Preferred stock, shares outstanding	0
Common stock, shares authorized	550,000,000	550,000,000
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares issued	110,000,000
Common stock, share outstanding	109,794,137
First Lien Debt Holders
Class of Stock [Line Items]
Common stock, share outstanding	99,300,000
Second Lien Debt Holders
Class of Stock [Line Items]
Common stock, share outstanding	4,400,000
PBGC (Pension Benefit Guaranty Corporation)
Class of Stock [Line Items]
Common stock, share outstanding	6,100,000
General Unsecured Creditor Reserve
Class of Stock [Line Items]
Common stock, shares, issued but not outstanding	200,000

Earnings (Loss) Per Common Sh83

Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016	Sep. 30, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Common stock, shares issued	110,000,000
Common stock, share outstanding	109,794,137
Numerator
Net income (loss)	$ 237
Dividends to preferred stockholders	0
Undistributed earnings	$ 237
Percentage allocated to common stockholders	100.00%
Numerator for basic and diluted earnings per common share	$ 237
Denominator
Denominator for basic earnings per weighted average common shares (shares)	109,800,000
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Warrants (shares)	0
Denominator for diluted earnings per weighted average common shares (shares)	110,300,000
Per common share net income (loss)
Basic (USD per share)	$ 2.16
Diluted (USD per share)	$ 2.15
Basic (shares)	109,800,000
Basic weighted average common stock and common stock equivalents (preferred shares)	109,800,000
Predecessor
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Common stock, shares issued				494,768,243
Common stock, share outstanding				494,768,243
Numerator
Net income (loss)		$ 2,977	$ (103)
Dividends to preferred stockholders		(6)	(8)
Undistributed earnings		$ 2,971	$ (111)
Percentage allocated to common stockholders		86.90%	100.00%
Numerator for basic and diluted earnings per common share		$ 2,582	$ (111)
Denominator
Denominator for basic earnings per weighted average common shares (shares)		497,300,000	497,000,000
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Warrants (shares)		0	0
Denominator for diluted earnings per weighted average common shares (shares)		497,300,000	497,000,000
Per common share net income (loss)
Basic (USD per share)		$ 5.19	$ (0.22)
Diluted (USD per share)		$ 5.19	$ (0.22)
Basic (shares)		497,300,000	497,000,000
Basic weighted average common stock and common stock equivalents (preferred shares)		572,400,000	497,000,000
Restricted stock units
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Share-based payment arrangements (shares)	500,000
Restricted stock units | Predecessor
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Share-based payment arrangements (shares)		0	0
Stock options
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Share-based payment arrangements (shares)	0
Stock options | Predecessor
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Share-based payment arrangements (shares)		0	0

Operating Segments (Details)

Operating Segments (Details) $ in Millions	Jul. 14, 2017segment	Jul. 13, 2017Segments	Dec. 31, 2017USD ($)	Dec. 15, 2017USD ($)	Dec. 31, 2017segment	Dec. 31, 2016USD ($)
Segment Reporting [Abstract]
Number of operating segments	2	3			2
Segment Reporting Information [Line Items]
REVENUE			$ 148
GROSS PROFIT			78
Selling, general and administrative			50
Research and development			9
Amortization of intangible assets			7
Restructuring charges, net			10
TOTAL OPERATING EXPENSES			76
OPERATING INCOME			2
INTEREST EXPENSE, OTHER (EXPENSE) INCOME, NET AND REORGANIZATION ITEMS, NET			(11)
(LOSS) INCOME BEFORE INCOME TAXES			(9)
Global Communications Solutions
Segment Reporting Information [Line Items]
REVENUE			71
Networking
Segment Reporting Information [Line Items]
REVENUE			0
Enterprise Collaboration Solutions
Segment Reporting Information [Line Items]
REVENUE			71
Avaya Global Services
Segment Reporting Information [Line Items]
REVENUE			77
Predecessor
Segment Reporting Information [Line Items]
REVENUE				$ 604		$ 875
GROSS PROFIT				362		535
Selling, general and administrative				264		336
Research and development				38		62
Amortization of intangible assets				10		57
Restructuring charges, net				14		10
TOTAL OPERATING EXPENSES				326		465
OPERATING INCOME				36		70
INTEREST EXPENSE, OTHER (EXPENSE) INCOME, NET AND REORGANIZATION ITEMS, NET				3,400		(170)
(LOSS) INCOME BEFORE INCOME TAXES				3,436		(100)
Predecessor | Global Communications Solutions
Segment Reporting Information [Line Items]
REVENUE				253		343
Predecessor | Networking
Segment Reporting Information [Line Items]
REVENUE				0		58
Predecessor | Enterprise Collaboration Solutions
Segment Reporting Information [Line Items]
REVENUE				253		401
Predecessor | Avaya Global Services
Segment Reporting Information [Line Items]
REVENUE				351		474
Operating Segments | Global Communications Solutions
Segment Reporting Information [Line Items]
GROSS PROFIT			41
Operating Segments | Networking
Segment Reporting Information [Line Items]
GROSS PROFIT			0
Operating Segments | Enterprise Collaboration Solutions
Segment Reporting Information [Line Items]
GROSS PROFIT			41
Operating Segments | Avaya Global Services
Segment Reporting Information [Line Items]
GROSS PROFIT			50
Operating Segments | Predecessor | Global Communications Solutions
Segment Reporting Information [Line Items]
GROSS PROFIT				169		231
Operating Segments | Predecessor | Networking
Segment Reporting Information [Line Items]
GROSS PROFIT				0		25
Operating Segments | Predecessor | Enterprise Collaboration Solutions
Segment Reporting Information [Line Items]
GROSS PROFIT				169		256
Operating Segments | Predecessor | Avaya Global Services
Segment Reporting Information [Line Items]
GROSS PROFIT				196		284
Unallocated Amounts
Segment Reporting Information [Line Items]
GROSS PROFIT			$ (13)
Unallocated Amounts | Predecessor
Segment Reporting Information [Line Items]
GROSS PROFIT				$ (3)		$ (5)

Accumulated Other Comprehensi85

Accumulated Other Comprehensive Income (Loss) - Schedule of Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
AOCI Attributable to Parent, Net of Tax
Beginning balance		$ 1,642
Elimination of Predecessor Company accumulated other comprehensive loss		0
Ending balance	$ 1,642	1,867	$ 1,642
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax
Beginning balance		0
Ending balance	0	(13)	0
Predecessor
AOCI Attributable to Parent, Net of Tax
Beginning balance		1,642	(5,013)
Other comprehensive income (loss) before reclassifications		(13)	(21)	$ 19
Amounts reclassified to earnings			16	20
Pension settlement			721
(Provision for) benefit from income taxes			(58)	2
Balance as of December 15, 2017 (Predecessor)	(1,380)		(1,380)
Elimination of Predecessor Company accumulated other comprehensive loss	1,380		790	0
Ending balance	1,642		1,642
Predecessor | Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax
Beginning balance		0	(1,448)	(1,661)
Balance as of December 15, 2017 (Predecessor)	(790)		(790)
Elimination of Predecessor Company accumulated other comprehensive loss	790
Ending balance	0	(13)	0	(1,624)
Predecessor | Change in unamortized pension, postretirement and postemployment benefit-related items
AOCI Attributable to Parent, Net of Tax
Beginning balance			(1,375)	(1,627)
Other comprehensive income (loss) before reclassifications		0	(24)	0
Amounts reclassified to earnings			16	20
Pension settlement			721
(Provision for) benefit from income taxes			(58)	6
Balance as of December 15, 2017 (Predecessor)	(720)		(720)
Elimination of Predecessor Company accumulated other comprehensive loss	720
Ending balance		0		(1,613)
Predecessor | Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax
Beginning balance			(72)	(33)
Other comprehensive income (loss) before reclassifications		(13)	3	19
Amounts reclassified to earnings			0	0
Pension settlement			0
(Provision for) benefit from income taxes			0	(4)
Balance as of December 15, 2017 (Predecessor)	(69)		(69)
Elimination of Predecessor Company accumulated other comprehensive loss	69
Ending balance		(13)		(10)
Predecessor | Other
AOCI Attributable to Parent, Net of Tax
Beginning balance			(1)	(1)
Other comprehensive income (loss) before reclassifications		0	0	0
Amounts reclassified to earnings			0	0
Pension settlement			0
(Provision for) benefit from income taxes			0	0
Balance as of December 15, 2017 (Predecessor)	(1)		$ (1)
Elimination of Predecessor Company accumulated other comprehensive loss	$ 1
Ending balance		$ 0		$ (1)

Related Party Transactions (Det

Related Party Transactions (Details)	1 Months Ended	2 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 15, 2017USD ($)	Dec. 31, 2017director	Sep. 30, 2017USD ($)
Related Party Transaction [Line Items]
Number of directors on the Successor Company's Board of Directors | director			7
Number of non-employee directors on the Successor Company's Board of Directors | director			6
Senior Vice President | Purchased goods and services from Koopid, Inc.
Related Party Transaction [Line Items]
Purchases from related party (less than)	$ 1,000,000
Director | Sales of products and services to Tenet Healthcare
Related Party Transaction [Line Items]
Sales to related party (less than)	1,000,000
Director | Sales of products and services to AIG
Related Party Transaction [Line Items]
Sales to related party (less than)	1,000,000
Director | Sales of products and services to Pitney Bowes Inc.
Related Party Transaction [Line Items]
Sales to related party (less than)	0
Chair of the Board of Directors | Purchased goods and services from Flex Ltd.
Related Party Transaction [Line Items]
Purchases from related party (less than)	$ 2,000,000
Predecessor | Senior Vice President | Purchased goods and services from Koopid, Inc.
Related Party Transaction [Line Items]
Purchases from related party (less than)		$ 1,000,000
Predecessor | Director | Sales of products and services to Tenet Healthcare
Related Party Transaction [Line Items]
Sales to related party (less than)		1,000,000
Predecessor | Director | Sales of products and services to AIG
Related Party Transaction [Line Items]
Sales to related party (less than)		2,000,000
Predecessor | Director | Sales of products and services to Pitney Bowes Inc.
Related Party Transaction [Line Items]
Sales to related party (less than)		1,000,000		$ 1,000,000
Predecessor | Chair of the Board of Directors | Purchased goods and services from Flex Ltd.
Related Party Transaction [Line Items]
Purchases from related party (less than)		6,000,000		$ 38,000,000
Predecessor | Affiliated Entity | Stockholders' agreement, registration rights agreement and management services agreement
Related Party Transaction [Line Items]
Expenses from transactions with related party (less than)		$ 1,000,000

Commitments And Contingencies -

Commitments And Contingencies - Narrative (Details)

Sep. 30, 2016claim

Nov. 10, 2014USD ($)

Sep. 30, 2014USD ($)

Mar. 27, 2014USD ($)claim

Dec. 31, 2017USD ($)

Sep. 30, 2016USD ($)

Dec. 15, 2017USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Jan. 31, 2017claim

Feb. 22, 2016USD ($)

Oct. 23, 2014USD ($)

Loss Contingencies [Line Items]

Legal fees

$ 0

Product warranty maximum duration

2 years

Maximum potential payment obligation with regards to letters of credit, guarantees and surety bonds

61,000,000

$ 61,000,000

Cash awards

0

Compensation expense

0

Lending institutions | Indemnification agreement

Loss Contingencies [Line Items]

Loss contingency accrual, payments

0

Loss contingency accrual

0

0

Nokia | Indemnification agreement

Loss Contingencies [Line Items]

Estimate of possible loss

50,000,000

50,000,000

Letter of Credit

Loss Contingencies [Line Items]

Cash collateral

$ 4,000,000

$ 4,000,000

Antitrust Litigation

Loss Contingencies [Line Items]

Number of claims settled | claim

2

Number of pending claims | claim

8

Damages awarded, value

$ 20,000,000

Damages awarded, value trebled

60,000,000

Amount awarded to other party

$ 71,000,000

$ 63,000,000

Prejudgment interest

$ 3,000,000

Bond posted

$ 8,000,000

$ 63,000,000

Damages sought, value

$ 61,000,000

Number of reinstated claims | claim

4

Number of vacated claim | claim

2

Patent Infringement Case Filed By BlackBerry Limited

Loss Contingencies [Line Items]

Number of pending claims | claim

2

Predecessor

Loss Contingencies [Line Items]

Legal fees

$ 37,000,000

$ 0

Commitments And Contingencies88

Commitments And Contingencies - Movement in Product Warranty Liability (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended
	Dec. 31, 2017	Dec. 15, 2017
Movement in product warranty liability:
Reductions for payments and costs to satisfy claims	$ (1)
Accruals for warranties issued during the period	1
Accrued warranty obligations, end	2
Predecessor
Movement in product warranty liability:
Accrued warranty obligations, start	$ 2	$ 2
Reductions for payments and costs to satisfy claims		(1)
Accruals for warranties issued during the period		1
Accrued warranty obligations, end		$ 2

Condensed Financial Informati89

Condensed Financial Information of Parent Company - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 15, 2017	Sep. 30, 2017
ASSETS
TOTAL ASSETS	$ 7,627
LIABILITIES
TOTAL LIABILITIES	5,760
Commitments and contingencies
Preferred stock
TOTAL STOCKHOLDERS' EQUITY (DEFICIT)	1,867	$ 1,642
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)	7,627
Predecessor
ASSETS
TOTAL ASSETS			$ 5,898
LIABILITIES
TOTAL LIABILITIES			10,327
Commitments and contingencies
Predecessor equity awards on redeemable shares			7
TOTAL STOCKHOLDERS' EQUITY (DEFICIT)		$ 1,642	(5,013)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)			5,898
Predecessor | Series A preferred stock
LIABILITIES
Preferred stock			184
Parent Company
ASSETS
Investment in Avaya Inc.	1,867
TOTAL ASSETS	1,867
LIABILITIES
Deficit in excess of investment in Avaya Inc.	0
TOTAL LIABILITIES	0
Commitments and contingencies
TOTAL STOCKHOLDERS' EQUITY (DEFICIT)	1,867
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)	1,867
Parent Company | Series B preferred stock
LIABILITIES
Preferred stock	0
Parent Company | Series A preferred stock
LIABILITIES
Preferred stock	$ 0
Parent Company | Predecessor
ASSETS
Investment in Avaya Inc.			0
TOTAL ASSETS			0
LIABILITIES
Deficit in excess of investment in Avaya Inc.			4,429
TOTAL LIABILITIES			4,429
Commitments and contingencies
Predecessor equity awards on redeemable shares			7
TOTAL STOCKHOLDERS' EQUITY (DEFICIT)			(5,013)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)			0
Parent Company | Predecessor | Series B preferred stock
LIABILITIES
Preferred stock			393
Parent Company | Predecessor | Series A preferred stock
LIABILITIES
Preferred stock			$ 184

Condensed Financial Informati90

Condensed Financial Information of Parent Company - Condensed Statements of Operations (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Condensed Income Statements, Captions [Line Items]
NET INCOME (LOSS)	$ 237
NET INCOME (LOSS) PER SHARE AVAILABLE TO COMMON STOCKHOLDERS
Basic (USD per share)	$ 2.16
Diluted (USD per share)	$ 2.15
Weighted average shares outstanding
Basic (shares)	109.8
Diluted (shares)	110.3
Predecessor
Condensed Income Statements, Captions [Line Items]
NET INCOME (LOSS)		$ 2,977	$ (103)
NET INCOME (LOSS) PER SHARE AVAILABLE TO COMMON STOCKHOLDERS
Basic (USD per share)		$ 5.19	$ (0.22)
Diluted (USD per share)		$ 5.19	$ (0.22)
Weighted average shares outstanding
Basic (shares)		497.3	497
Diluted (shares)		497.3	497
Parent Company
Condensed Income Statements, Captions [Line Items]
Equity in net income (loss) of Avaya Inc.	$ 237
NET INCOME (LOSS)	$ 237
NET INCOME (LOSS) PER SHARE AVAILABLE TO COMMON STOCKHOLDERS
Basic (USD per share)	$ 2.16
Diluted (USD per share)	$ 2.15
Weighted average shares outstanding
Basic (shares)	109.8
Diluted (shares)	110.3
Parent Company | Predecessor
Condensed Income Statements, Captions [Line Items]
Equity in net income (loss) of Avaya Inc.		$ 2,977	$ (103)
NET INCOME (LOSS)		$ 2,977	$ (103)
NET INCOME (LOSS) PER SHARE AVAILABLE TO COMMON STOCKHOLDERS
Basic (USD per share)		$ 5.19	$ (0.22)
Diluted (USD per share)		$ 5.19	$ (0.22)
Weighted average shares outstanding
Basic (shares)		497.3	497
Diluted (shares)		497.3	497

Condensed Financial Informati91

Condensed Financial Information of Parent Company - Condensed Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	Dec. 15, 2017	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Condensed Statement of Income Captions [Line Items]
Net income (loss)		$ 237
Other comprehensive (loss) income		(13)
Elimination of Predecessor Company accumulated other comprehensive loss		0
Total comprehensive income (loss)		224
Predecessor
Condensed Statement of Income Captions [Line Items]
Net income (loss)			$ 2,977	$ (103)
Other comprehensive (loss) income			658	37
Elimination of Predecessor Company accumulated other comprehensive loss	$ 1,380		790	0
Total comprehensive income (loss)			4,425	(66)
Parent Company
Condensed Statement of Income Captions [Line Items]
Net income (loss)		237
Other comprehensive (loss) income		(13)
Elimination of Predecessor Company accumulated other comprehensive loss		0
Total comprehensive income (loss)		$ 224
Parent Company | Predecessor
Condensed Statement of Income Captions [Line Items]
Net income (loss)			2,977	(103)
Other comprehensive (loss) income			658	37
Elimination of Predecessor Company accumulated other comprehensive loss			790	0
Total comprehensive income (loss)			$ 4,425	$ (66)

Condensed Financial Informati92

Condensed Financial Information of Parent Company - Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 31, 2017	Dec. 15, 2017	Dec. 31, 2016
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
NET CASH PROVIDED BY (USED FOR) OPERATING ACTIVITIES	$ 66
Net cash provided by (used for) investing activities	8
Net cash provided by (used for) financing activities	0
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	77
Cash and cash equivalents at beginning of period	340
Cash and cash equivalents at end of period	417	$ 340
Predecessor
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
NET CASH PROVIDED BY (USED FOR) OPERATING ACTIVITIES		(440)	$ (44)
Net cash provided by (used for) investing activities		8	(15)
Net cash provided by (used for) financing activities		(102)	(57)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS		(536)	(127)
Cash and cash equivalents at beginning of period	340	876	336
Cash and cash equivalents at end of period		340	209
Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
Net income (loss)	237
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Equity in net income (loss) of Avaya Inc.	(237)
NET CASH PROVIDED BY (USED FOR) OPERATING ACTIVITIES	0
Net cash provided by (used for) investing activities	0
Net cash provided by (used for) financing activities	0
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	0
Cash and cash equivalents at beginning of period	0
Cash and cash equivalents at end of period	0	0
Parent Company | Predecessor
Condensed Cash Flow Statements, Captions [Line Items]
Net income (loss)		2,977	(103)
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Equity in net income (loss) of Avaya Inc.		(2,977)	103
NET CASH PROVIDED BY (USED FOR) OPERATING ACTIVITIES		0	0
Net cash provided by (used for) investing activities		0	0
Net cash provided by (used for) financing activities		0	0
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS		0	0
Cash and cash equivalents at beginning of period	$ 0	0	0
Cash and cash equivalents at end of period		$ 0	$ 0

Subsequent Events (Details)

Subsequent Events (Details)	Jan. 29, 2018
Intellisist, Inc. | Subsequent Event
Business Acquisition [Line Items]
Expected closing period	2 months

Uncategorized Items - cik000111

Label	Element	Value
Common Stock [Member] | Predecessor [Member]
Cancellation Of Predecessor Equity, Shares	cik0001116521_CancellationOfPredecessorEquityShares	494,800,000
Retained Earnings [Member] | Predecessor [Member]
Cancellation Of Predecessor Equity	cik0001116521_CancellationOfPredecessorEquity	$ (2,977,000,000)
Additional Paid-in Capital [Member] | Predecessor [Member]
Cancellation Of Predecessor Equity	cik0001116521_CancellationOfPredecessorEquity	$ 2,387,000,000