The 2013 reversal of previously recorded regulatory disallowances.

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2016 revenues related to advanced metering costs as proposed in stipulation agreement.

+ References

No definition available.

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- Definition

Additional requested annual increase.

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- Definition

Amount of interim rates implemented in January 2015, subject to refund, as approved by the LPSC in partial settlement agreement.

+ References

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Base rate increase per the settlement agreement.

+ References

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- Definition

Fourteen months of revenue beginning November 2014 related to advanced metering costs as proposed in stipulation agreement.

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No definition available.

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- Definition

Fuel rate decrease per the settlement agreement.

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- Definition

Louisiana jurisdictional share of the Turk Plant.

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- Definition

Net increase in Louisiana total rates per the settlement agreement.

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- Definition

Projected capital costs of property, plant and equipment.

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- Definition

Proposed increase in depreciation rates included in requested base rate increase.

+ References

No definition available.

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- Definition

Reduction to the requested revenue increase as approved by the LPSC in the stipulation agreement.

+ References

No definition available.

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- Definition

Requested annual increase.

+ References

No definition available.

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- Definition

Requested base rate increase.

+ References

No definition available.

+ Details

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- Definition

Requested return on equity.

+ References

No definition available.

+ Details

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- Definition

Requested total annual increase.

+ References

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- Definition

The resulting annual base rate increase subsequent to recent rulings by the PUCT.

+ References

No definition available.

+ Details

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- Definition

Return on common equity for AFUDC and Factoring as Proposed in Stipulation Agreement.

+ References

No definition available.

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- Definition

Return on common equity per the settlement agreement.

+ References

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- Definition

Year one revenues related to proposed recovery of advanced metering costs.

+ References

No definition available.

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- Definition

Year three revenues related to proposed recovery of advanced metering costs.

+ References

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- Definition

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

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Period end amount of total net PPE.

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No definition available.

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- Definition

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

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

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-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 6

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Rate Matters - West Companies (Details) (USD $)	3 Months Ended	1 Months Ended
Rate Matters - West Companies (Details) (USD $)	Mar. 31, 2015	Apr. 23, 2015	Dec. 31, 2014
Public Utilities, General Disclosures [Line Items]
Construction Work in Progress	$ 3,710,000,000us-gaap_ConstructionInProgressGross		$ 3,218,000,000us-gaap_ConstructionInProgressGross
Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Construction Work in Progress	218,241,000		204,753,000
Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Construction Work in Progress	519,678,000		471,980,000
Louisiana 2012 Formula Rate Filing [Member]
Public Utilities, General Disclosures [Line Items]
Louisiana Jurisdictional Share of the Turk Plant	29.00%
Net Increase in Louisiana Total Rates per the Settlement Agreement	2,000,000
Base Rate Increase per the Settlement Agreement	85,000,000
Fuel Rate Decrease per the Settlement Agreement	83,000,000
Return on Common Equity per the Settlement Agreement	10.00%
Reduction To Requested Revenue Increase As Approved In Stipulation Agreement	3,000,000
Louisiana 2012 Formula Rate Filing [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Louisiana Jurisdictional Share of the Turk Plant	29.00%
Net Increase in Louisiana Total Rates per the Settlement Agreement	2,000,000
Base Rate Increase per the Settlement Agreement	85,000,000
Fuel Rate Decrease per the Settlement Agreement	83,000,000
Return on Common Equity per the Settlement Agreement	10.00%
Reduction To Requested Revenue Increase As Approved In Stipulation Agreement	3,000,000
Louisiana 2014 Formula Rate Filing [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase	5,000,000
Additional Requested Annual Increase	15,000,000
Requested Total Annual Increase	20,000,000
Amount Of Interim Rates Implemented In January 2015 As Approved In Partial Settlement Agreement	15,000,000
Louisiana 2014 Formula Rate Filing [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase	5,000,000
Additional Requested Annual Increase	15,000,000
Requested Total Annual Increase	20,000,000
Amount Of Interim Rates Implemented In January 2015 As Approved In Partial Settlement Agreement	15,000,000
Oklahoma Base Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
Requested Base Rate Increase	38,000,000
Requested Return on Equity	10.50%
Proposed Depreciation Increase Included in Requested Rate Increase	29,000,000
Year One Revenues Related to Proposed Recovery of Advanced Metering Costs	7,000,000
Year Three Revenues Related to Proposed Recovery of Advanced Metering Costs	28,000,000
Fourteen Months Of Revenues Beginning November 2014 Related To Advanced Metering Costs As Proposed In Stipulation Agreement	24,000,000
2016 Revenues Related to Advanced Metering Costs as Proposed in Stipulation Agreement	27,000,000
Return on Common Equity for AFUDC and Factoring as Proposed in Stipulation Agreement	9.85%
Oklahoma Base Rate Case [Member] \| Public Service Co Of Oklahoma [Member]
Public Utilities, General Disclosures [Line Items]
Requested Base Rate Increase	38,000,000
Requested Return on Equity	10.50%
Proposed Depreciation Increase Included in Requested Rate Increase	29,000,000
Year One Revenues Related to Proposed Recovery of Advanced Metering Costs	7,000,000
Year Three Revenues Related to Proposed Recovery of Advanced Metering Costs	28,000,000
Fourteen Months Of Revenues Beginning November 2014 Related To Advanced Metering Costs As Proposed In Stipulation Agreement	24,000,000
2016 Revenues Related to Advanced Metering Costs as Proposed in Stipulation Agreement	27,000,000
Return on Common Equity for AFUDC and Factoring as Proposed in Stipulation Agreement	9.85%
Texas Base Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
2013 Reversal of Previously Recorded Regulatory Disallowances	114,000,000
Resulting Approved Base Rate Increase	52,000,000
Texas Base Rate Case [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
2013 Reversal of Previously Recorded Regulatory Disallowances	114,000,000
Resulting Approved Base Rate Increase	52,000,000
Texas Base Rate Case [Member] \| Welsh Plant, Unit 2 [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	84,000,000
Texas Base Rate Case [Member] \| Welsh Plant, Unit 2 [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	84,000,000
Welsh Plant, Units 1 and 3 - Environmental Projects [Member]
Public Utilities, General Disclosures [Line Items]
Projected Capital Costs	600,000,000
Construction Work in Progress	211,000,000
Remaining Contractual Construction Obligations	84,000,000
Welsh Plant, Units 1 and 3 - Environmental Projects [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Projected Capital Costs	600,000,000
Construction Work in Progress	211,000,000
Remaining Contractual Construction Obligations	84,000,000
Welsh Plant, Units 1 and 3 - Environmental Projects [Member] \| Welsh Plant, Units 1 and 3 [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	431,000,000
Welsh Plant, Units 1 and 3 - Environmental Projects [Member] \| Welsh Plant, Units 1 and 3 [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Property, Plant and Equipment, Net	431,000,000
Subsequent Event [Member] \| Louisiana 2015 Formula Rate Filing [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase		14,000,000
Subsequent Event [Member] \| Louisiana 2015 Formula Rate Filing [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Requested Annual Increase		14,000,000
Mercury and Air Toxic Standards [Member] \| Welsh Plant, Units 1 and 3 - Environmental Projects [Member]
Public Utilities, General Disclosures [Line Items]
Projected Capital Costs	410,000,000
Mercury and Air Toxic Standards [Member] \| Welsh Plant, Units 1 and 3 - Environmental Projects [Member] \| Southwestern Electric Power Co [Member]
Public Utilities, General Disclosures [Line Items]
Projected Capital Costs	$ 410,000,000