STATEMENTS OF CAPITALIZATION (Parenthetical) (USD $)	12 Months Ended
Dec. 31, 2014
Common Stockholder's Equity
Common stock, shares authorized (in shares)	200us-gaap_CommonStockSharesAuthorized
Common stock, par value (in dollars per share)	1.00
Common stock, shares outstanding (in shares)	100us-gaap_CommonStockSharesOutstanding
First Mortgage Bonds \| Series Due June 15, 2024
Long-Term Debt
Debt instrument, Interest Rate, Stated Percentage	3.30%
Debt Instrument, Maturity Date	Jun. 15, 2024
First Mortgage Bonds \| Series Due Aug. 15, 2041
Long-Term Debt
Debt instrument, Interest Rate, Stated Percentage	4.50%
Debt Instrument, Maturity Date	Aug. 15, 2041
Unsecured Senior Notes \| Senior E Due Oct. 1, 2016
Long-Term Debt
Debt instrument, Interest Rate, Stated Percentage	5.60%
Debt Instrument, Maturity Date	Oct. 01, 2016
Unsecured Senior Notes \| Senior G Due Dec. 1, 2018
Long-Term Debt
Debt instrument, Interest Rate, Stated Percentage	8.75%
Debt Instrument, Maturity Date	Dec. 01, 2018
Unsecured Senior Notes \| Senior C and D Due Oct. 1, 2033
Long-Term Debt
Debt instrument, Interest Rate, Stated Percentage	6.00%
Debt Instrument, Maturity Date	Oct. 01, 2033
Unsecured Senior Notes \| Senior F Due Oct. 1, 2036
Long-Term Debt
Debt instrument, Interest Rate, Stated Percentage	6.00%
Debt Instrument, Maturity Date	Oct. 01, 2036

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Face amount or stated value per share of common stock.

+ References

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 210.5-02.29)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

+ Details

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

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-Name Accounting Standards Codification

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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

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-Name Accounting Standards Codification

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-Subparagraph (SX 210.5-02.22(a)(1))

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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

-Publisher SEC

-Name Regulation S-X (SX)

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