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EMPLOYEE RETIREMENT PLANS - Qualified Defined-benefit Pension Plan Weighted Average Asset Allocation (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Plan Assets
Unfunded commitments	$ 2
Qualified
Plan Assets
Weighted average asset allocation (as a percent)	100.00%	100.00%
Qualified | Equity securities
Plan Assets
Weighted average asset allocation (as a percent)	55.00%	49.00%
Qualified | Debt securities
Plan Assets
Weighted average asset allocation (as a percent)	28.00%	32.00%
Qualified | Other
Plan Assets
Weighted average asset allocation (as a percent)	17.00%	19.00%

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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=65897934&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=65897934&loc=d3e1928-114920

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The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=SL6742756-110258

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