DEBT - Schedule of Debt (Details) - USD ($)	1 Months Ended
	Jul. 31, 2019	Jun. 30, 2019	Feb. 28, 2019	Jan. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal amount		$ 24,066,171,000				$ 23,296,581,000
Carrying amount		23,640,509,000				22,812,600,000
Finance lease obligation		27,096,000				25,190,000
Current portion of finance lease obligations		(6,464,000)			$ (5,928,000)	(5,928,000)
Supply chain financing agreement		39,856,000
Collateralized indebtedness
Debt Instrument [Line Items]
Principal amount		1,459,638,000				1,459,638,000
Collateralized indebtedness outstanding		1,417,647,000				1,406,182,000
Loans Payable
Debt Instrument [Line Items]
Principal amount		102,622,000				106,108,000
Carrying amount		102,622,000				106,108,000
Long-term Debt
Debt Instrument [Line Items]
Principal amount		23,402,474,000				23,137,956,000
Long-term debt, net of current maturities		22,980,286,000				22,653,975,000
CSC Holdings | Senior Notes | CSC Holdings 8.625% Notes due February 15, 2019
Debt Instrument [Line Items]
Principal amount		0				526,000,000
Carrying amount		$ 0				527,749,000
Interest rate		8.625%
CSC Holdings | Senior Notes | CSC Holdings 6.75% Notes due November 15, 2021
Debt Instrument [Line Items]
Principal amount		$ 1,000,000,000				1,000,000,000
Carrying amount		$ 974,093,000				969,285,000
Interest rate		6.75%
CSC Holdings | Senior Notes | CSC Holdings 5.25% Notes due June 1, 2024
Debt Instrument [Line Items]
Principal amount		$ 750,000,000				750,000,000
Carrying amount		$ 677,720,000				671,829,000
Interest rate		5.25%
CSC Holdings | Senior Notes | CSC Holdings 10.125% Notes due January 15, 2023
Debt Instrument [Line Items]
Principal amount		$ 0				1,800,000,000
Carrying amount		$ 0				1,781,424,000
Interest rate		10.125%
CSC Holdings | Senior Notes | 10.875% Notes due October 15, 2025
Debt Instrument [Line Items]
Principal amount		$ 1,684,221,000				1,684,221,000
Carrying amount		$ 1,664,092,000				1,663,027,000
Interest rate		10.875%
CSC Holdings | Senior Notes | CSC Holdings 5.125% Notes due December 15, 2021
Debt Instrument [Line Items]
Principal amount		$ 1,240,762,000				1,240,762,000
Carrying amount		$ 1,168,267,000				1,155,264,000
Interest rate		5.125%
CSC Holdings | Senior Notes | CSC Holdings Senior Notes due 2025, 7.75%
Debt Instrument [Line Items]
Principal amount		$ 617,881,000				617,881,000
Carrying amount		$ 604,712,000				603,889,000
Interest rate		7.75%
CSC Holdings | Senior Notes | CSC Holdings 7.500% Notes due April 1, 2028
Debt Instrument [Line Items]
Principal amount		$ 1,045,882,000				1,045,882,000
Carrying amount		$ 1,044,209,000				1,044,143,000
Interest rate		7.50%
CSC Holdings | Collateralized indebtedness | CSC Holdings 6.625% Notes due October 15, 2025
Debt Instrument [Line Items]
Principal amount		$ 1,000,000,000				1,000,000,000
Carrying amount		$ 988,750,000				988,052,000
Interest rate		6.625%
CSC Holdings | Collateralized indebtedness | CSC Holdings 5.5% Notes due April 15, 2027
Debt Instrument [Line Items]
Principal amount		$ 1,310,000,000				1,310,000,000
Carrying amount		$ 1,305,177,000				1,304,936,000
Interest rate		5.50%
CSC Holdings | Collateralized indebtedness | 5.375% Senior Guaranteed Notes Due February 1, 2028
Debt Instrument [Line Items]
Principal amount		$ 1,000,000,000				1,000,000,000
Carrying amount		$ 992,403,000				992,064,000
Interest rate		5.375%
CSC Holdings | Collateralized indebtedness | CSC Holdings 5.375% Senior Guaranteed Notes due July 15, 2023
Debt Instrument [Line Items]
Principal amount		$ 1,095,825,000				1,095,825,000
Carrying amount		$ 1,080,114,000				1,078,428,000
Interest rate		5.375%
CSC Holdings | Collateralized indebtedness | CSC Holdings 5.500% Notes due May 15, 2026
Debt Instrument [Line Items]
Principal amount		$ 1,498,806,000				1,498,806,000
Carrying amount		$ 1,485,076,000				1,484,278,000
Interest rate		5.50%
CSC Holdings | Collateralized indebtedness | CSC Holdings 6.500% Notes due February 1, 2019
Debt Instrument [Line Items]
Principal amount		$ 1,750,000,000				0
Carrying amount		$ 1,746,881,000				0
Interest rate		6.50%
CSC Holdings | Collateralized indebtedness | Incremental Term Loan B-4
Debt Instrument [Line Items]
Principal amount			$ 1,000,000,000
Cablevision Systems Corp. | Senior Notes
Debt Instrument [Line Items]
Principal amount		$ 15,157,145,000				15,733,145,000
Carrying amount		14,835,813,000				15,359,561,000
Cablevision Systems Corp. | Senior Notes | Cablevision 8.0% Notes due April 15, 2020
Debt Instrument [Line Items]
Principal amount		500,000,000				500,000,000
Carrying amount		$ 497,045,000				495,302,000
Interest rate		8.00%
Cablevision Systems Corp. | Senior Notes | Cablevision 5.875% Notes due September 15, 2022
Debt Instrument [Line Items]
Principal amount		$ 649,024,000				649,024,000
Carrying amount		$ 593,104,000				585,817,000
Interest rate		5.875%
Cablevision Systems Corp. | Senior Notes | Cablevision 5.125% Notes due December 15, 2021
Debt Instrument [Line Items]
Principal amount		$ 8,886,000				8,886,000
Carrying amount		$ 8,367,000				8,274,000
Interest rate		5.125%
Cablevision Systems Corp. | Senior Notes | Cablevision 7.750% Notes due July 15, 2025
Debt Instrument [Line Items]
Principal amount		$ 1,740,000				1,740,000
Carrying amount		$ 1,692,000				1,690,000
Interest rate		7.75%
Cablevision Systems Corp. | Senior Notes | Cablevision 7.500% Notes due April 1, 2028
Debt Instrument [Line Items]
Principal amount		$ 4,118,000				4,118,000
Carrying amount		$ 4,111,000				4,110,000
Interest rate		7.50%
Revolving Credit Facility | CSC Holdings Revolving Credit Facility
Debt Instrument [Line Items]
Letters of credit outstanding		$ 178,014,000
Facility undrawn and available		1,674,129,000
Revolving Credit Facility | CSC Holdings Revolving Credit Facility Due November 30, 2021
Debt Instrument [Line Items]
Maximum borrowing capacity		200,000,000
Revolving Credit Facility | CSC Holdings
Debt Instrument [Line Items]
Carrying amount		$ 950,000,000
Interest rate		4.73%
Maximum borrowing capacity		$ 622,857,000		$ 2,475,000,000		250,000,000
Debt outstanding		609,754,000				231,425,000
Line of Credit | CSC Holdings
Debt Instrument [Line Items]
Maximum borrowing capacity		7,319,670,000				5,972,500,000
Debt outstanding		$ 7,257,331,000				5,915,559,000
Line of Credit | CSC Holdings | Term B Loan Facility
Debt Instrument [Line Items]
Interest rate		4.644%
Maximum borrowing capacity		$ 2,940,000,000				2,955,000,000
Debt outstanding		$ 2,925,564,000				2,939,425,000
Line of Credit | CSC Holdings | Incremental Term Loan B-2
Debt Instrument [Line Items]
Interest rate		4.894%
Maximum borrowing capacity		$ 1,485,000,000				1,492,500,000
Debt outstanding		$ 1,469,340,000				1,475,778,000
Line of Credit | CSC Holdings | Incremental Term Loan B-3
Debt Instrument [Line Items]
Interest rate		4.644%
Maximum borrowing capacity		$ 1,271,813,000				1,275,000,000
Debt outstanding		$ 1,266,155,000				1,268,931,000
Line of Credit | CSC Holdings | Incremental Term Loan B-4
Debt Instrument [Line Items]
Interest rate		5.394%
Maximum borrowing capacity		$ 1,000,000,000				0
Debt outstanding		986,518,000				0
Senior Notes
Debt Instrument [Line Items]
Principal amount		508,886,000				0
Current portion of long-term debt		(505,412,000)				0
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		67,750,000				54,563,000
Current portion of long-term debt		(67,750,000)				(54,563,000)
Loans Payable
Debt Instrument [Line Items]
Principal amount		80,597,000				98,134,000
Current portion of long-term debt		(80,597,000)				(98,134,000)
Short-term Debt
Debt Instrument [Line Items]
Principal amount		663,697,000				158,625,000
Current portion of long-term debt		$ (660,223,000)				$ (158,625,000)
Subsequent Event | Senior Notes | Cablevision 5.125% Notes due December 15, 2021
Debt Instrument [Line Items]
Redeemed debt	$ 8,886,000
Subsequent Event | Senior Notes | Senior Notes Due January 2030
Debt Instrument [Line Items]
Principal amount	$ 1,000,000,000
Interest rate	5.75%