DEBT - CSC Holdings Credit Facilities (Details) - USD ($)		1 Months Ended					3 Months Ended	12 Months Ended
	Mar. 15, 2017	Oct. 31, 2019	Jul. 31, 2019	Feb. 28, 2019	Jan. 31, 2018	Apr. 30, 2017	Jun. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 21, 2016
Debt Instrument [Line Items]
Principal amount								$ 24,817,366,000	$ 23,296,581,000
Redeemed debt								8,886,000
Redemption of debt amount								4,225,786,000	2,628,962,000	$ 1,729,400,000
Loss on extinguishment of debt and write-off of deferred financing costs	$ 18,976,000							243,806,000	48,804,000	600,240,000
Cash distributions to shareholders							$ 839,700,000		1,499,935,000	840,035,000	$ 445,176,000
Proceeds from credit facility debt, net of discounts								5,040,000,000	3,489,313,000	5,593,675,000
Repayments of line of credit								3,832,062,000	2,221,175,000	4,411,581,000
Loss on extinguishment of debt and write-off of deferred financing costs (including $513,723 related to affiliates and related parties in 2017) (See Note 16)	(18,976,000)							(243,806,000)	(48,804,000)	(600,240,000)
CSC Holdings
Debt Instrument [Line Items]
Redemption of debt amount								3,703,454,000	805,206,000	350,120,000
Loss on extinguishment of debt and write-off of deferred financing costs								228,130,000	7,883,000	53,988,000
Cash distributions to shareholders									3,058,747,000	2,777,498,000
Proceeds from credit facility debt, net of discounts								5,040,000,000	3,489,313,000	5,593,675,000
Repayments of line of credit								3,832,062,000	2,221,175,000	4,411,581,000
Loss on extinguishment of debt and write-off of deferred financing costs (including $513,723 related to affiliates and related parties in 2017) (See Note 16)								(228,130,000)	(7,883,000)	(53,988,000)
Retained Earnings (Accumulated Deficit) | CSC Holdings
Debt Instrument [Line Items]
Cash distributions to shareholders									1,672,031,000
CSC Holdings Term Loan Facility
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs								8,313,000
Loss on extinguishment of debt and write-off of deferred financing costs (including $513,723 related to affiliates and related parties in 2017) (See Note 16)								(8,313,000)
5.5% Notes due April 15, 2027 | Secured Debt [Member]
Debt Instrument [Line Items]
Principal amount								$ 1,310,000,000	$ 1,310,000,000
Stated interest rate								5.50%
CSC Holdings 8.625% Notes due September 15, 2017 | Senior Notes
Debt Instrument [Line Items]
Redeemed debt						$ 500,000,000
8.625% Notes due September 15, 2017
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs										6,300,000
Loss on extinguishment of debt and write-off of deferred financing costs (including $513,723 related to affiliates and related parties in 2017) (See Note 16)										$ (6,300,000)
8.625% Notes due September 15, 2017 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate						8.625%
CSC Credit Facilities
Debt Instrument [Line Items]
Percentage of proceeds from asset sales required to pay down term loans								100.00%
Percentage of excess cash flow required when minimum leverage ratio is not met									50.00%
Percentage of excess cash flow required to pay down term loans when minimum leverage ratio is fulfilled								0.00%
Minimum debt leverage ratio required for zero percent of excess cash flow obligation to prepay debt								4.5
Line of credit facility, covenant, leverage ratio								5.0
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
Loss on extinguishment of debt and write-off of deferred financing costs (including $513,723 related to affiliates and related parties in 2017) (See Note 16)								(500,000)
Cablevision 5.125% Notes due December 15, 2021 | Senior Notes
Debt Instrument [Line Items]
Principal amount								$ 0	$ 8,886,000
Stated interest rate								5.125%
Redeemed debt								$ 8,886,000
Term Loan B-2 and Term Loan B-4 [Member]
Debt Instrument [Line Items]
Redeemed debt								2,500,000
Cash distributions to shareholders								500,000,000
8.0% Notes due April 15, 2020
Debt Instrument [Line Items]
Loss on extinguishment of debt and write-off of deferred financing costs								15,176,000
Loss on extinguishment of debt and write-off of deferred financing costs (including $513,723 related to affiliates and related parties in 2017) (See Note 16)								(15,176,000)
8.0% Notes due April 15, 2020 | Senior Notes
Debt Instrument [Line Items]
Principal amount								$ 0	500,000,000
Stated interest rate								8.00%
Secured Debt [Member] | CSC Holdings Term Loan Facility
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity									3,000,000,000
Principal amount	3,000,000,000								2,925,000,000
Deferred financing costs	4,390,000
Issue discount	15,000,000
Line of credit facility, increase in borrowing capacity	$ 500,000,000
Repayments of lines of credit						$ 2,493,750,000
Line of credit facility periodic payment, percentage of principal	0.25%
Line of credit facility, periodic payment amount	$ 7,500,000
Secured Debt [Member] | CSC Holdings Term Loan Facility | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%
Secured Debt [Member] | CSC Holdings Term Loan Facility | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Secured Debt [Member] | CSC Holdings Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Secured Debt [Member] | Incremental Term Loan B-2
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 1,500,000,000
Principal amount								$ 0	1,492,500,000
Price percent					99.50%
Line of credit facility periodic payment, percentage of principal					0.25%
Line of credit facility, periodic payment amount					$ 3,750,000
Secured Debt [Member] | Incremental Term Loan B-2 | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate					1.50%
Secured Debt [Member] | Incremental Term Loan B-2 | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate					2.50%
Secured Debt [Member] | Incremental Term Loan B-3
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity									1,275,000,000
Principal amount								1,265,438,000	1,275,000,000
Line of credit facility periodic payment, percentage of principal	0.25%
Line of credit facility, periodic payment amount	$ 3,188,000
Secured Debt [Member] | Incremental Term Loan B-4
Debt Instrument [Line Items]
Principal amount								1,000,000,000
Debt discount rate				1.00%
Secured Debt [Member] | Incremental Term Loan B-4 | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate				3.00%
Secured Debt [Member] | Incremental Term Loan B-5
Debt Instrument [Line Items]
Principal amount								3,000,000,000	0
Line of credit facility, periodic payment amount	$ 7,500
Debt Instrument, Premium Percentage		1.00%
Secured Debt [Member] | Incremental Term Loan B-5 | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate		1.50%
Secured Debt [Member] | Incremental Term Loan B-5 | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate		2.50%
Revolving Credit Facility | CSC Holdings Revolving Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity								2,275,000,000				$ 2,475,000,000
Principal amount								0	$ 250,000,000
Proceeds from credit facility debt, net of discounts								1,050,000,000
Repayments of line of credit			$ 622,857,000					$ 1,300,000