Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

Name:	us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for a long-term debt where the holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=atus_CSCHoldings7.625NotesdueJuly152018Member
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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Namespace Prefix:
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SUBSEQUENT EVENT (Details) - USD ($)		1 Months Ended	6 Months Ended
SUBSEQUENT EVENT (Details) - USD ($)	Jul. 15, 2018	Apr. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Subsequent Event [Line Items]
Repayments of Senior Debt			$ 2,123,756,000	$ 979,280,000
Debt face amount			5,722,350,000		$ 4,693,675,000
Senior Notes
Subsequent Event [Line Items]
Debt face amount			16,239,245,000		16,289,245,000
CSC Holdings 7.625% Notes due July 15, 2018 [Member] \| Senior Notes
Subsequent Event [Line Items]
Debt face amount			$ 500,000,000		500,000,000
Stated interest rate			7.625%
CSC Holdings 7.625% Notes due July 15, 2018 [Member] \| Senior Notes \| Subsequent Event
Subsequent Event [Line Items]
Repayments of Senior Debt	$ 500,000,000
Cequel and Cequel Capital 6.375% Senior Notes due September 15, 2020 [Member] \| Senior Notes
Subsequent Event [Line Items]
Debt face amount			$ 0		$ 1,050,000,000
Stated interest rate			6.375%
Extinguishment of debt		$ 16,737,000