Document and Entity Information - shares	3 Months Ended
	Sep. 30, 2020	Oct. 23, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-16441
Entity Registrant Name	CROWN CASTLE INTERNATIONAL CORP.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	76-0470458
Entity Address, Address Line One	1220 Augusta Drive
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77057-2261
City Area Code	713
Local Phone Number	570-3000
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	CCI
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		431,297,846
Entity Central Index Key	0001051470
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false