FAIR VALUE MEASUREMENT - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	$ 24,355,941	$ 24,350,865
Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	25,202,473	25,892,634
CSC Holdings | Credit facility debt | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	7,139,133	7,148,287
CSC Holdings | Credit facility debt | Estimated Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	7,179,750	7,190,438
CSC Holdings | Collateralized indebtedness | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	1,593,073	1,585,088
CSC Holdings | Collateralized indebtedness | Estimated Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	1,689,819	1,611,095
CSC Holdings | Senior guaranteed notes | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	7,604,509	7,602,456
CSC Holdings | Senior guaranteed notes | Estimated Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	7,943,752	8,220,518
CSC Holdings | Senior notes | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	7,884,080	7,874,040
CSC Holdings | Senior notes | Estimated Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	8,253,080	8,728,870
CSC Holdings | Notes payable and supply chain financing | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	135,146	140,994
CSC Holdings | Notes payable and supply chain financing | Estimated Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	$ 136,072	$ 141,713