DEBT - Senior Guaranteed Notes, Senior Secured Notes, and Senior Notes and Debentures (Details) - USD ($)	1 Months Ended		12 Months Ended
	Sep. 30, 2020	Oct. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 21, 2016
Debt Instrument [Line Items]
Principal amount			$ 26,671,018,000	$ 26,940,911,000
Loss on extinguishment of debt and write-off of deferred financing costs			51,712,000	250,489,000	$ 243,806,000
Issuance of common shares pursuant to employee long term incentive plan			13,900,000	15,752,000	(7,122,000)
Collateralized Agreements			89,898,000
Cablevision 5.125% Notes due December 15, 2021
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs					500,000
CSC Holdings Revolving Credit Facility, Portion Due October 9, 2020 | Revolving Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				200,000
CSC Holdings 5.125% Notes due December 15, 2021
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs					$ 65,151,000
CSC Holdings Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Principal amount			900,000,000	625,000,000
Line of Credit Facility, Maximum Borrowing Capacity			2,475,000,000			$ 2,475,000,000
Cablevision Lightpath Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Principal amount			0	0
Line of Credit Facility, Maximum Borrowing Capacity			100,000,000
Incremental Term Loan B-3 | Secured Debt [Member]
Debt Instrument [Line Items]
Principal amount			1,239,938,000	1,252,688,000
10.875% Notes due October 15, 2025
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs				136,249,000
6.625% Notes due October 15, 2025
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs				52,144,000
Cablevision Lightpath Term B Loan | Secured Debt [Member]
Debt Instrument [Line Items]
Principal amount			594,000,000	600,000,000
Line of credit facility periodic payment, percentage of principal	0.25%
Line of Credit Facility, Periodic Payment	$ 1,500,000
Cablevision Lightpath Term B Loan | Secured Debt [Member] | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Cablevision Lightpath Term B Loan | Secured Debt [Member] | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate	3.25%
Incremental Term Loan B-5 | Secured Debt [Member]
Debt Instrument [Line Items]
Principal amount			2,947,500,000	2,977,500,000
Line of Credit Facility, Maximum Borrowing Capacity			3,000,000,000
Incremental Term Loan B-5 | Secured Debt [Member] | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate		1.50%
Incremental Term Loan B-5 | Secured Debt [Member] | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate		2.50%
CSC Holdings 7.750% Notes due July 15, 2025
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs				35,375,000
Senior Notes | CSC Holdings 5.750% Notes due January 15, 2030
Debt Instrument [Line Items]
Principal amount			$ 2,250,000,000	2,250,000,000
Stated interest rate			5.75%
Debt Instrument, Redemption Price, Percentage			104.00%
Senior Notes | 10.125% Notes due January 15, 2023
Debt Instrument [Line Items]
Stated interest rate			10.125%
Debt Instrument, Redemption Price, Percentage			107.594%
Senior Notes | CSC Holdings 5.750% Notes due January 15, 2030 Tranche 1 [Member]
Debt Instrument [Line Items]
Principal amount			$ 1,000,000,000
Senior Notes | CSC Holdings 5.750% Notes due January 15, 2030 Tranche 2 [Member]
Debt Instrument [Line Items]
Principal amount			$ 1,250,000,000
Senior Notes | CSC Holdings 5.125% Notes due December 15, 2021
Debt Instrument [Line Items]
Principal amount				1,240,762,000
Stated interest rate			5.125%
Senior Notes | CSC Holdings 4.625% Notes due December 1, 2030
Debt Instrument [Line Items]
Principal amount			$ 2,325,000,000	2,325,000,000
Stated interest rate			4.625%
Debt instrument, percent of premium issued			103.25%
Senior Notes | CSC Holdings 5.375% Senior Guaranteed Notes due July 15, 2023
Debt Instrument [Line Items]
Stated interest rate			5.375%
Senior Notes | Cablevision 7.750% Notes due July 15, 2025
Debt Instrument [Line Items]
Principal amount				1,740,000
Stated interest rate			7.75%
Senior Notes | CSC Holdings 4.625% Notes due December 1, 2030 - August 2020 [Member]
Debt Instrument [Line Items]
Principal amount			$ 1,700,000,000
Stated interest rate			4.625%
Senior Notes | 10.875% Notes due October 15, 2025
Debt Instrument [Line Items]
Principal amount				1,684,221,000
Stated interest rate			10.875%
Senior Notes | Cablevision Lightpath LLC 5.625% Notes due September 15, 2028
Debt Instrument [Line Items]
Principal amount			$ 415,000,000	415,000,000
Stated interest rate			5.625%
Senior Notes | 5.875% Notes due September 15, 2022
Debt Instrument [Line Items]
Principal amount			$ 649,024,000	649,024,000
Stated interest rate			5.875%
Senior Notes | CSC Holdings 7.750% Notes due July 15, 2025
Debt Instrument [Line Items]
Principal amount				617,881,000
Stated interest rate			7.75%
Senior Notes | Cablevision 7.500% Notes due April 1, 2028
Debt Instrument [Line Items]
Principal amount			$ 4,118,000	4,118,000
Stated interest rate			7.50%
Senior Notes | CSC Holdings 5.000% Notes due November 15, 2031
Debt Instrument [Line Items]
Principal amount			$ 500,000,000
Stated interest rate			5.00%
Secured Debt [Member] | 5.5% Notes due April 15, 2027
Debt Instrument [Line Items]
Principal amount			$ 1,310,000,000	1,310,000,000
Stated interest rate			5.50%
Secured Debt [Member] | CSC Holdings 6.500% Notes due February 1, 2029 Tranche 2 [Member]
Debt Instrument [Line Items]
Principal amount			$ 250,000,000
Redemption of debt amount			$ 905,300,000
Premium on notes			101.75%
Secured Debt [Member] | CSC Holdings 6.500% Notes due February 1, 2029 Tranche 1 [Member]
Debt Instrument [Line Items]
Principal amount			$ 1,500,000,000
Secured Debt [Member] | CSC Holdings 4.125% Notes due December 1, 2030
Debt Instrument [Line Items]
Principal amount			$ 1,100,000,000	1,100,000,000
Stated interest rate			4.125%
Secured Debt [Member] | CSC Holdings 4.625% Notes due December 1, 2030
Debt Instrument [Line Items]
Principal amount			$ 625,000,000
Stated interest rate			4.625%
Secured Debt [Member] | CSC Holdings 5.375% Senior Guaranteed Notes due July 15, 2023
Debt Instrument [Line Items]
Principal amount				1,095,825,000
Secured Debt [Member] | CSC Holdings 3.375% Notes due February 15, 2031
Debt Instrument [Line Items]
Principal amount			$ 1,000,000,000	1,000,000,000
Stated interest rate			3.375%
Secured Debt [Member] | 6.625% Notes due October 15, 2025
Debt Instrument [Line Items]
Principal amount				1,000,000,000
Stated interest rate			6.625%
Secured Debt [Member] | Cablevision Lightpath LLC 3.875% Notes due September 15, 2027
Debt Instrument [Line Items]
Principal amount			$ 450,000,000	450,000,000
Stated interest rate			3.875%
Secured Debt [Member] | CSC Holdings 5.500% Notes due May 15, 2026
Debt Instrument [Line Items]
Principal amount			$ 0	1,498,806,000
Stated interest rate			5.50%
Loss on extinguishment of debt and write-off of deferred financing costs			$ (51,712,000)
Secured Debt [Member] | CSC Holdings 4.500% Senior Guaranteed Notes due November 15, 2031
Debt Instrument [Line Items]
Principal amount			$ 1,500,000,000
Stated interest rate			4.50%
Long-term Debt
Debt Instrument [Line Items]
Principal amount			$ 25,739,991,000	$ 25,685,115,000