v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2017
Nov. 02, 2017
Dec. 31, 2016
Entity Information [Line Items]      
Common Stock, Shares, Outstanding 406,274,802   360,536,659
Entity Voluntary Filers No    
Entity Registrant Name CROWN CASTLE INTERNATIONAL CORP    
Entity Central Index Key 0001051470    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Document Type 10-Q    
Document Period End Date Sep. 30, 2017    
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus Q3    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   406,275,091  
Entity Current Reporting Status Yes