COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Capital Lease
2019	$ 4.5
2020	4.5
2021	4.5
2022	4.5
2023	4.5
Thereafter	21.6
Total	44.1
Firm Transportation and Storage Contracts [Abstract]
2019	63.7
2020	51.6
2021	35.7
2022	22.4
2023	17.3
Thereafter	11.7
Total	$ 202.4
Other Significant Noncash Transaction, Description	(a) - At December 31, 2018, $28 million in principal represents noncash financing activities.

No definition available.

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The remaining amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation to be paid after five years from the balance sheet date.

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No definition available.

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The remaining amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation to be paid within one year of the balance sheet date.

+ References

No definition available.

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The remaining amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation to be paid in more than three and within four years from the balance sheet date.

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No definition available.

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The remaining amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation to be paid in more than two and within three years from the balance sheet date.

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No definition available.

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The remaining amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation to be paid in more than one and within two years from the balance sheet date.

+ References

No definition available.

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The amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation as of the balance sheet date.

+ References

No definition available.

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The remaining amount of the fixed and determinable portion of an unrecorded firm transportation and storage contract purchase obligation to be paid in more than four and within five years from the balance sheet date.

+ References

No definition available.

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Amount of minimum lease payments for capital leases.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
-Paragraph 1
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Amount of minimum lease payments for capital leases due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of minimum lease payments for capital leases due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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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.

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A textual description of other significant noncash (or part noncash) investing and financing activities required to be supplementally disclosed to enable users of the financial information to fully understand the period cash flows of the Entity in relation to the statements of financial position, income statement, and statement of changes in shareholders' equity. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of a transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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