Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 11, 2022	Jun. 30, 2021
Document and Entity Information [Abstract]
Title of 12(b) Security	Class A Common Stock, par value $0.01 per share
Entity Interactive Data Current	Yes
Entity File Number	001-38126
Document Transition Report	false
Document Quarterly Report	true
Document Type	10-K
Entity Central Index Key	0001702780
Entity Registrant Name	Altice USA, Inc.
Document Fiscal Year Focus	2020
Entity Filer Category	Large Accelerated Filer
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Period End Date	Dec. 31, 2021
Entity Common Stock, Shares Outstanding		454,654,354
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 7,528,969,035
Documents Incorporated by Reference	Altice USA, Inc. intends to file with the Securities and Exchange Commission, not later than 120 days after the close of its fiscal year, a definitive proxy statement or an amendment to this report filed under cover of Form 10-K/A containing the information required to be disclosed under Part III of Form 10-K.
Entity Small Business	false
Current Fiscal Year End Date	--12-31
Entity Tax Identification Number	38-3980194
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	1 Court Square West
Entity Address, City or Town	Long Island City,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	11101
City Area Code	(516)
Local Phone Number	803-2300
Trading Symbol	ATUS
Security Exchange Name	NYSE
ICFR Auditor Attestation Flag	true
Auditor Name	KPMG LLP
Auditor Location	New York, New York
Auditor Firm ID	185