Basis of Presentation	6 Months Ended
Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Unless the context requires otherwise, "NII Holdings, Inc.," "NII Holdings," "we," "our," "us" and "the Company" refer to the combined businesses of NII Holdings, Inc. and its consolidated subsidiaries. Our unaudited condensed consolidated financial statements have been prepared under the rules and regulations of the Securities and Exchange Commission, or the SEC. While these financial statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements, they reflect all adjustments that, in the opinion of management, are necessary for a fair presentation of the results for interim periods. In addition, the year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States. We refer to our wholly-owned Brazilian operating company, Nextel Telecomunicações Ltda., as Nextel Brazil. You should read these condensed consolidated financial statements in conjunction with the consolidated financial statements and notes contained in our annual report on Form 10-K for the year ended December 31, 2015 and the condensed consolidated financial statements contained in our quarterly report on Form 10-Q for the three months ended March 31, 2016. You should not expect results of operations for interim periods to be an indication of the results for a full year. Our consolidated results from continuing operations in this quarterly report on Form 10-Q include the results of operations of Nextel Brazil and our corporate headquarters. Revision of Prior Period Financial Statements. In connection with the preparation of our condensed consolidated financial statements for the three months ended March 31, 2016, we determined that an error existed in our previously issued financial statements. Specifically, selling, general and administrative expenses for the six months ended December 31, 2015 were understated by $6.9 million as the result of a failure to properly accrue expenses for services Nextel Brazil received under a management consulting services arrangement. We evaluated this error under the SEC's authoritative guidance on materiality and the quantification of the effect of prior period misstatements on financial statements, and we determined that the impact of this error on our prior period consolidated financial statements is immaterial. However, since the correction of this error in the first quarter of 2016 would have been material to our results of operations for the three months ended March 31, 2016 and may be material to our results of operations for the year ending December 31, 2016, we revised our prior period financial statements to correct this error. As a result of the correction of this error, as of December 31, 2015, accrued expenses and other increased by $6.8 million, accumulated deficit increased by $6.9 million and accumulated other comprehensive loss decreased by $0.1 million. Although not presented herein, for the six months ended December 31, 2015, this error resulted in a $6.9 million increase to selling, general and administrative expenses, operating loss, loss from continuing operations before reorganization items and income tax benefit, net loss from continuing operations and net loss. In addition, for the six months ended December 31, 2015, the correction of this error resulted in a $0.07 increase in both net loss from continuing operations per basic and diluted common share and net loss per basic and diluted common share. This error did not relate to any periods prior to the six months ended December 31, 2015. Sale of Nextel Argentina. On September 11, 2015, two of our indirect subsidiaries entered into a binding agreement with Grupo Clarin S.A., or Grupo Clarin, relating to the sale of all of the outstanding equity interests of Nextel Communications Argentina, S.R.L., or Nextel Argentina, which was completed on January 27, 2016. See Note 4 for more information on this sale. In connection with this transaction, we have presented Nextel Argentina's results for all periods as discontinued operations in this quarterly report on Form 10-Q. Reorganization Accounting. In accordance with the requirements of reorganization accounting, NII Holdings adopted the provisions of fresh start accounting as of June 30, 2015 and became a new entity for financial reporting purposes. References to the "Successor Company" relate to NII Holdings on or subsequent to June 30, 2015. References to the "Predecessor Company" relate to NII Holdings prior to June 30, 2015. See Note 2 for more information regarding the implementation of fresh start accounting. Going Concern. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. These condensed consolidated financial statements do not include any adjustments that might result from the occurrence of the uncertainties described below. In connection with the agreements governing Nextel Brazil's local bank loans, we are required to meet a net debt financial covenant semiannually. In August 2016, Nextel Brazil secured waivers from the lenders of its local bank loans related to this financial covenant for the June 30, 2016 measurement date. The next measurement date for this financial covenant will be December 31, 2016. Based on our current outlook, which reflects significant uncertainty about the economic and competitive conditions in Brazil that are currently impacting our ability to increase our revenues and generate profitability, we believe it is unlikely that we will satisfy the applicable financial covenant included in both of Nextel Brazil's local bank loan agreements as of the December 31, 2016 measurement date. If we are unable to develop or implement changes to our business that allow us to meet this covenant, we will need to refinance or negotiate amendments to these loan arrangements or secure additional waivers from the lenders in order to avoid a potential default under the loan agreements. If a default under these local bank loans occurs, the lenders could require us to repay the amounts outstanding under these arrangements, and if they were to do so, the lender of Nextel Brazil's equipment financing facility could accelerate the amount outstanding under that obligation as well. As of June 30, 2016, we had $280.7 million principal amount outstanding under Nextel Brazil's local bank loans and $318.0 million principal amount outstanding under Nextel Brazil’s equipment financing facility. See Note 6 for more information. Because it is unlikely that we will satisfy the applicable financial covenant included in both of Nextel Brazil's local bank loans as of the December 31, 2016 measurement date, and because of the cross-default provisions included in Nextel Brazil's equipment financing facility as described above, we concluded that the circumstances described above continue to raise substantial doubt about our ability to continue as a going concern as of June 30, 2016. Reclassifications. We have reclassified some prior period amounts in our condensed consolidated financial statements to conform to our current year presentation. New Accounting Pronouncements. There were no new accounting standards issued during the three months ended June 30, 2016 that materially impacted our condensed consolidated financial statements or could materially impact our financial statements or related disclosures in a future period.

Basis of Presentation

Unless the context requires otherwise, "NII Holdings, Inc.," "NII Holdings," "we," "our," "us" and "the Company" refer to the combined businesses of NII Holdings, Inc. and its consolidated subsidiaries. Our unaudited condensed consolidated financial statements have been prepared under the rules and regulations of the Securities and Exchange Commission, or the SEC. While these financial statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements, they reflect all adjustments that, in the opinion of management, are necessary for a fair presentation of the results for interim periods. In addition, the year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States. We refer to our wholly-owned Brazilian operating company, Nextel Telecomunicações Ltda., as Nextel Brazil.

You should read these condensed consolidated financial statements in conjunction with the consolidated financial statements and notes contained in our annual report on Form 10-K for the year ended December 31, 2015 and the condensed consolidated financial statements contained in our quarterly report on Form 10-Q for the three months ended March 31, 2016. You should not expect results of operations for interim periods to be an indication of the results for a full year. Our consolidated results from continuing operations in this quarterly report on Form 10-Q include the results of operations of Nextel Brazil and our corporate headquarters.

Revision of Prior Period Financial Statements. In connection with the preparation of our condensed consolidated financial statements for the three months ended March 31, 2016, we determined that an error existed in our previously issued financial statements. Specifically, selling, general and administrative expenses for the six months ended December 31, 2015 were understated by $6.9 million as the result of a failure to properly accrue expenses for services Nextel Brazil received under a management consulting services arrangement. We evaluated this error under the SEC's authoritative guidance on materiality and the quantification of the effect of prior period misstatements on financial statements, and we determined that the impact of this error on our prior period consolidated financial statements is immaterial. However, since the correction of this error in the first quarter of 2016 would have been material to our results of operations for the three months ended March 31, 2016 and may be material to our results of operations for the year ending December 31, 2016, we revised our prior period financial statements to correct this error.

As a result of the correction of this error, as of December 31, 2015, accrued expenses and other increased by $6.8 million, accumulated deficit increased by $6.9 million and accumulated other comprehensive loss decreased by $0.1 million. Although not presented herein, for the six months ended December 31, 2015, this error resulted in a $6.9 million increase to selling, general and administrative expenses, operating loss, loss from continuing operations before reorganization items and income tax benefit, net loss from continuing operations and net loss. In addition, for the six months ended December 31, 2015, the correction of this error resulted in a $0.07 increase in both net loss from continuing operations per basic and diluted common share and net loss per basic and diluted common share. This error did not relate to any periods prior to the six months ended December 31, 2015.

Sale of Nextel Argentina. On September 11, 2015, two of our indirect subsidiaries entered into a binding agreement with Grupo Clarin S.A., or Grupo Clarin, relating to the sale of all of the outstanding equity interests of Nextel Communications Argentina, S.R.L., or Nextel Argentina, which was completed on January 27, 2016. See Note 4 for more information on this sale. In connection with this transaction, we have presented Nextel Argentina's results for all periods as discontinued operations in this quarterly report on Form 10-Q.

Reorganization Accounting. In accordance with the requirements of reorganization accounting, NII Holdings adopted the provisions of fresh start accounting as of June 30, 2015 and became a new entity for financial reporting purposes. References to the "Successor Company" relate to NII Holdings on or subsequent to June 30, 2015. References to the "Predecessor Company" relate to NII Holdings prior to June 30, 2015. See Note 2 for more information regarding the implementation of fresh start accounting.

Going Concern. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. These condensed consolidated financial statements do not include any adjustments that might result from the occurrence of the uncertainties described below.

In connection with the agreements governing Nextel Brazil's local bank loans, we are required to meet a net debt financial covenant semiannually. In August 2016, Nextel Brazil secured waivers from the lenders of its local bank loans related to this financial covenant for the June 30, 2016 measurement date. The next measurement date for this financial covenant will be December 31, 2016. Based on our current outlook, which reflects significant uncertainty about the economic and competitive conditions in Brazil that are currently impacting our ability to increase our revenues and generate profitability, we believe it is unlikely that we will satisfy the applicable financial covenant included in both of Nextel Brazil's local bank loan agreements as of the December 31, 2016 measurement date. If we are unable to develop or implement changes to our business that allow us to meet this covenant, we will need to refinance or negotiate amendments to these loan arrangements or secure additional waivers from the lenders in order to avoid a potential default under the loan agreements. If a default under these local bank loans occurs, the lenders could require us to repay the amounts outstanding under these arrangements, and if they were to do so, the lender of Nextel Brazil's equipment financing facility could accelerate the amount outstanding under that obligation as well. As of June 30, 2016, we had $280.7 million principal amount outstanding under Nextel Brazil's local bank loans and $318.0 million principal amount outstanding under Nextel Brazil’s equipment financing facility. See Note 6 for more information.

Because it is unlikely that we will satisfy the applicable financial covenant included in both of Nextel Brazil's local bank loans as of the December 31, 2016 measurement date, and because of the cross-default provisions included in Nextel Brazil's equipment financing facility as described above, we concluded that the circumstances described above continue to raise substantial doubt about our ability to continue as a going concern as of June 30, 2016.

Reclassifications. We have reclassified some prior period amounts in our condensed consolidated financial statements to conform to our current year presentation.

New Accounting Pronouncements. There were no new accounting standards issued during the three months ended June 30, 2016 that materially impacted our condensed consolidated financial statements or could materially impact our financial statements or related disclosures in a future period.