PENSION AND POST-RETIREMENT PLANS - ASSET ALLOCATION (Details) - plan	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Employee benefit plans
Number of single-employer defined benefit pension funded plans	2
Pension Benefits
Employee benefit plans
Target allocation (as a percent)	100.00%
Asset allocations (as a percent)	100.00%	100.00%
One year returns (losses) on plan assets (as a percent)	14.60%
Three year returns (losses) on plan assets (as a percent)	6.70%
Five year returns (losses) on plan assets (as a percent)	9.30%
Long-term average return on plan assets since inception (as a percent)	8.50%
Pension Benefits \| Domestic equity securities
Employee benefit plans
Target allocation (as a percent)	53.00%
Asset allocations (as a percent)	59.00%	62.00%
Pension Benefits \| International equity securities
Employee benefit plans
Target allocation (as a percent)	15.00%
Asset allocations (as a percent)	17.00%	13.00%
Pension Benefits \| Debt securities
Employee benefit plans
Target allocation (as a percent)	22.00%
Asset allocations (as a percent)	17.00%	17.00%
Pension Benefits \| Real estate
Employee benefit plans
Target allocation (as a percent)	5.00%
Asset allocations (as a percent)	6.00%	6.00%
Pension Benefits \| Other and cash
Employee benefit plans
Target allocation (as a percent)	5.00%
Asset allocations (as a percent)	1.00%	2.00%

The percentage of five-year returns (losses) on pension plan assets.

No definition available.

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- Definition

The percentage of long-term average return on pension plan assets.

+ References

No definition available.

+ Details

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- Definition

The percentage of one-year returns (losses) on pension plan assets.

+ References

No definition available.

+ Details

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- Definition

The percentage of three-year returns (losses) on pension plan assets.

+ References

No definition available.

+ Details

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- Definition

Represents the number of single employer defined benefit pension funded plans.

+ References

No definition available.

+ Details

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- Definition

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

No definition available.

+ Details

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(i)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2446-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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