Document and Entity Information (USD $)
12 Months Ended
Dec. 31, 2014
Feb. 28, 2015
Jun. 30, 2014
Dec. 31, 2013
Common stock, shares authorized 600,000,000     600,000,000
Document Type 10-K      
Amendment Flag false      
Document Period End Date Dec. 31, 2014      
Document Fiscal Year Focus 2014      
Document Fiscal Period Focus FY      
Entity Public Float     $ 94,798,954  
Entity Registrant Name NII HOLDINGS INC      
Entity Central Index Key 0001037016      
Entity Tax Identification Number 911671412      
Current Fiscal Year End Date --12-31      
Entity Current Reporting Status Yes      
Entity Filer Category Accelerated Filer      
Entity Common Stock, Shares Outstanding   172,363,259    
Entity Well-known Seasoned Issuer No      
Entity Voluntary Filers No