COMMITMENTS AND CONTINGENCIES - Other Commitments - Delivery, operating leases (Details) $ in Millions	12 Months Ended
Dec. 31, 2015 USD ($) MMcf
Natural Gas Sales Contracts [Member]
Delivery Commitments
Volume of gas deliverable (in Bcf) \| MMcf	56,000
Delivery term	3 years
Financial commitment upon nondelivery	$ 116.7
Gas Gathering And Processing Agreements [Member]
Delivery Commitments
Delivery term	10 years
Financial commitment upon nondelivery	$ 203.0
Minimum Volume Agreement [Member]
Delivery Commitments
Financial commitment upon nondelivery	12.4
Accrued liabilities	9.7
Other Transportation, Delivery And Facilities Commitments [Member]
Delivery Commitments
Other commitments	$ 36.3

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Total amount of product committed to be supplied under existing contracts or agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1207
-Paragraph (a)
-Subparagraph (2)

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- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

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- Definition

Total financial obligation resulting from inability to meet short-term or long-term contractual delivery obligations.

+ References

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- Definition

This element represents the period for delivery of oil and gas under terms of contracts and agreements in effect at balance sheet date.

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