FAIR VALUE MEASUREMENT - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Carrying Amount
Liabilities:
Debt, fair value	$ 26,564,475	$ 26,562,705
Estimated Fair Value
Liabilities:
Debt, fair value	26,859,426	27,811,011
Fair Value, Inputs, Level 2 [Member] \| Carrying Amount \| Credit facility debt \| CSC Holdings
Liabilities:
Debt, fair value	7,762,412	8,288,000
Fair Value, Inputs, Level 2 [Member] \| Carrying Amount \| Secured Debt [Member] \| CSC Holdings
Liabilities:
Debt, fair value	1,697,235	1,617,506
Fair Value, Inputs, Level 2 [Member] \| Carrying Amount \| Senior guaranteed notes and senior secured notes \| CSC Holdings
Liabilities:
Debt, fair value	8,076,365	8,066,796
Fair Value, Inputs, Level 2 [Member] \| Carrying Amount \| Senior notes \| CSC Holdings
Liabilities:
Debt, fair value	8,941,847	8,415,602
Fair Value, Inputs, Level 2 [Member] \| Carrying Amount \| Notes payable and supply chain financing \| CSC Holdings
Liabilities:
Debt, fair value	86,616	174,801
Fair Value, Inputs, Level 2 [Member] \| Estimated Fair Value \| Credit facility debt \| CSC Holdings
Liabilities:
Debt, fair value	7,816,125	8,350,188
Fair Value, Inputs, Level 2 [Member] \| Estimated Fair Value \| Secured Debt [Member] \| CSC Holdings
Liabilities:
Debt, fair value	1,751,341	1,692,724
Fair Value, Inputs, Level 2 [Member] \| Estimated Fair Value \| Senior guaranteed notes and senior secured notes \| CSC Holdings
Liabilities:
Debt, fair value	8,214,982	8,567,858
Fair Value, Inputs, Level 2 [Member] \| Estimated Fair Value \| Senior notes \| CSC Holdings
Liabilities:
Debt, fair value	8,990,552	9,024,990
Fair Value, Inputs, Level 2 [Member] \| Estimated Fair Value \| Notes payable and supply chain financing \| CSC Holdings
Liabilities:
Debt, fair value	86,426	175,251
Fair Value Measured on a Recurring Basis \| Fair Value, Inputs, Level 1 [Member]
Assets:
Investment securities		2,250,854
Prepaid forward contracts \| Fair Value Measured on a Recurring Basis \| Fair Value, Inputs, Level 2 [Member]
Assets:
Derivative asset	0	45,653
Liabilities:
Derivative liability	356,873	293,506
Interest rate swap contracts \| Fair Value Measured on a Recurring Basis \| Fair Value, Inputs, Level 2 [Member]
Assets:
Derivative asset	3,555	9,906
Liabilities:
Derivative liability	168,129	275,297
Money market funds \| Fair Value Measured on a Recurring Basis \| Fair Value, Inputs, Level 1 [Member]
Assets:
Money market funds	$ 159,001	$ 50,236

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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