| Cover Page DEI Document | Aug. 17, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 17, 2021 |
| Entity Registrant Name | Crown Castle International Corp |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-16441 |
| Entity Tax Identification Number | 76-0470458 |
| Entity Address, Address Line One | 8020 Katy Freeway |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77024-1908 |
| City Area Code | 713 |
| Local Phone Number | 570-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001051470 |
| Amendment Flag | false |
| New York Stock Exchange | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | CCI |
| Security Exchange Name | NYSE |
