SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES REVENUE AND CUSTOMER RECEIVABLES (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Customer Concentration Risk customer
Revenue from External Customers
Unbilled revenues	$ 79.0	$ 70.5
Customers that account for more than 10% of revenues			0
Threshold percentage of revenues from major customers or industries			10.00%
Percentage of revenues from an industry that exceeds 10% of revenues			12.00%
Percentage price variance from rate case-approved fuel and purchased power costs before deferral is required	2.00%

For an unclassified balance sheet, the amount of fees and other revenue, excluding investment income receivable, earned but not yet received, which were recognized in conformity with revenue recognition criteria based on estimates or specific contractual terms.

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 210.5-02.3)

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13537-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13531-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

+ Details

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- Details

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- Definition

The number of customers that accounted for more than 10% of the entity's revenues.

+ References

No definition available.

+ Details

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- Definition

Percentage of revenue generated from a single industry that accounts for 10 percent or more of an entity's revenues.

+ References

No definition available.

+ Details

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- Definition

Represents the threshold percentage from which actual fuel and purchased power costs can vary from costs charged to customers before deferral is required.

+ References

No definition available.

+ Details

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