v3.10.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2018
Nov. 02, 2018
Dec. 31, 2017
Entity Information [Line Items]      
Common Stock, Shares, Outstanding 415,000,000   406,000,000
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, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus Q3    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   414,850,442  
Entity Current Reporting Status Yes    
Entity Emerging Growth Company false    
Entity Small Business false