DESCRIPTION OF BUSINESS AND RELATED MATTERS (Details)	1 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($) shares	Dec. 31, 2021 USD ($) segment $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 21, 2020 USD ($) shares	Nov. 23, 2020 USD ($)	Nov. 20, 2020 USD ($)	Jul. 31, 2019 USD ($)	Dec. 31, 2018 shares	Jun. 08, 2018 USD ($)
Business Acquisition [Line Items]
Number of segments | segment		1
Implied enterprise value of subsidiary			$ 3,200,000,000
Proceeds from Sale of Interest in Partnership Unit			2,355,000,000
Gross Cash Proceeds from Sale of Interest in Partnership Unit			890,000,000
Cash from debt incurred in connection with the Sale of Interest in Partnership Unit			1,465,000,000
Gain on sale of minority interest in subsidiary			650,270,000
Tax effect on net proceeds received over the book value of the interest sold in Partnership Unit		$ 228,489,000	$ 228,489,000
Share repurchase authorized							$ 2,000,000,000			$ 2,000,000,000
Maximum Amount Offered on Commencement of Tender Offer						$ 2,500,000,000
Maximum price for Tender Offer						36.00
Minimum price for Tender Offer						$ 32.25
Shares purchased in connection with Tender Offer | shares					64,613,479
Accepted price paid for tendered shares					$ 36.00
Cost of shares paid in connection with Tender Offer					$ 2,326,949,000
Shares repurchased (in shares) | shares		23,593,728	161,216,653	72,668,712
Value of shares repurchased		$ 804,928,000	$ 4,816,895,000	$ 1,686,873,000
Availability remaining under its stock repurchase program		1,191,302,000
Principal Amount		$ 26,671,018,000	$ 26,940,911,000
Cash dividends declared per common share | $ / shares		$ 0	$ 0	$ 0
Goodwill	$ 8,142,309,000	$ 8,205,863,000	$ 8,160,566,000	$ 8,142,309,000
Total shares authorized for repurchase
Business Acquisition [Line Items]
Share repurchase authorized		$ 9,000,000
Cablevision Lightpath LLC [Member] | Cablevision Lightpath LLC [Member]
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			49.99%
Ownership percentage of noncontrolling interest			50.01%
Common Class A
Business Acquisition [Line Items]
Common stock, shares outstanding (in shares) | shares	446,749,307	270,320,798	290,573,672	446,749,307					496,064,027
Common Class B
Business Acquisition [Line Items]
Shares repurchased (in shares) | shares		0	0	0
Common stock, shares outstanding (in shares) | shares	186,245,832	184,333,342	185,895,903	186,245,832					212,976,259
Common stock conversion ratio		1
Neptune Holdings LP Acquisition [Member] | Common Class A
Business Acquisition [Line Items]
Number of shares issued (in shares) | shares	6,290,292
2019 Share Repurchase Authorization [Member]
Business Acquisition [Line Items]
Share repurchase authorized								$ 5,000,000,000
10.875% Notes due October 15, 2025 | Senior Notes
Business Acquisition [Line Items]
Principal Amount			$ 1,684,221,000
Stated interest rate		10.875%
10.125% Notes due January 15, 2023 | Senior Notes
Business Acquisition [Line Items]
Stated interest rate		10.125%
6.625% Notes due October 15, 2025 | Secured Debt [Member]
Business Acquisition [Line Items]
Principal Amount			1,000,000,000
Stated interest rate		6.625%
CSC Holdings
Business Acquisition [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net			(3,000)
Gain on sale of minority interest in subsidiary			(650,444,000)
Proceeds from (Payments for) Other Financing Activities		$ 24,961,000	40,972,000	$ 25,083,000
Distribution Made to Limited Liability Company (LLC) Member, Non-cash Distributions Paid		19,500,000
Goodwill		8,205,863,000	8,160,566,000
Retained Earnings [Member]
Business Acquisition [Line Items]
Value of shares repurchased		(804,692,000)	(1,812,590,000)
Additional Paid-in Capital [Member]
Business Acquisition [Line Items]
Gain on sale of minority interest in subsidiary			741,471,000
Stock Issued During Period Relating to Acquisition				163,862,000
Value of shares repurchased		0	3,002,693,000	1,686,146,000
Additional Paid-in Capital [Member] | CSC Holdings
Business Acquisition [Line Items]
Gain on sale of minority interest in subsidiary			$ (741,645,000)
Distribution Made to Limited Liability Company (LLC) Member, Non-cash Distributions Paid		$ 19,500,000
Treasury Stock [Member]
Business Acquisition [Line Items]
Stock Issued During Period Relating to Acquisition				$ 163,862,000