Rate Matters - West Companies (Details) (USD $)							9 Months Ended										9 Months Ended						9 Months Ended								1 Months Ended		9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Public Service Co Of Oklahoma [Member]	Dec. 31, 2013 Public Service Co Of Oklahoma [Member]	Sep. 30, 2014 Southwestern Electric Power Co [Member]	Dec. 31, 2013 Southwestern Electric Power Co [Member]	Sep. 30, 2014 Louisiana 2012 Formula Rate Filing [Member]	Sep. 30, 2014 Louisiana 2012 Formula Rate Filing [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Louisiana 2014 Formula Rate Filing [Member]	Sep. 30, 2014 Louisiana 2014 Formula Rate Filing [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Oklahoma Base Rate Case [Member]	Sep. 30, 2014 Oklahoma Base Rate Case [Member] Public Service Co Of Oklahoma [Member]	Sep. 30, 2014 Texas Base Rate Case [Member]	Sep. 30, 2014 Texas Base Rate Case [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Texas Base Rate Case [Member] Welsh Plant, Unit 2 [Member]	Sep. 30, 2014 Texas Base Rate Case [Member] Welsh Plant, Unit 2 [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Texas Transmission Cost Recovery Factor Filing [Member]	Sep. 30, 2014 Texas Transmission Cost Recovery Factor Filing [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Welsh Plant, Units 1 and 3 - Environmental Projects [Member]	Sep. 30, 2014 Welsh Plant, Units 1 and 3 - Environmental Projects [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Welsh Plant, Units 1 and 3 - Environmental Projects [Member] Welsh Plant, Units 1 and 3 [Member]	Sep. 30, 2014 Welsh Plant, Units 1 and 3 - Environmental Projects [Member] Welsh Plant, Units 1 and 3 [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Minimum [Member] Oklahoma Base Rate Case [Member]	Sep. 30, 2014 Minimum [Member] Oklahoma Base Rate Case [Member] Public Service Co Of Oklahoma [Member]	Sep. 30, 2014 Minimum [Member] Texas Transmission Cost Recovery Factor Filing [Member]	Sep. 30, 2014 Minimum [Member] Texas Transmission Cost Recovery Factor Filing [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Maximum [Member] Oklahoma Base Rate Case [Member]	Sep. 30, 2014 Maximum [Member] Oklahoma Base Rate Case [Member] Public Service Co Of Oklahoma [Member]	Sep. 30, 2014 Maximum [Member] Texas Transmission Cost Recovery Factor Filing [Member]	Sep. 30, 2014 Maximum [Member] Texas Transmission Cost Recovery Factor Filing [Member] Southwestern Electric Power Co [Member]	Oct. 23, 2014 Subsequent Event [Member] Texas Transmission Cost Recovery Factor Filing [Member]	Oct. 23, 2014 Subsequent Event [Member] Texas Transmission Cost Recovery Factor Filing [Member] Southwestern Electric Power Co [Member]	Sep. 30, 2014 Mercury and Air Toxic Standards [Member] Welsh Plant, Units 1 and 3 - Environmental Projects [Member]	Sep. 30, 2014 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]
Property, Plant and Equipment, Net															$ 85,000,000	$ 85,000,000					$ 335,000,000	$ 335,000,000
2013 Reversal of Previously Recorded Regulatory Disallowances													114,000,000	114,000,000
Resulting Approved Base Rate Increase													52,000,000	52,000,000
Requested Transmission Cost Recovery Factor Revenue																	15,000,000	15,000,000
Intervenor Recommended Increase To Annual Revenue																									1,000,000	1,000,000			10,000,000	10,000,000
Annual Increase in Revenue as Recommended by Administrative Law Judge																															14,000,000	14,000,000
Louisiana Jurisdictional Share of the Turk Plant							29.00%	29.00%
Net Increase in Louisiana Total Rates per the Settlement Agreement							2,000,000	2,000,000
Base Rate Increase per the Settlement Agreement							85,000,000	85,000,000
Fuel Rate Decrease per the Settlement Agreement							83,000,000	83,000,000
Return on Common Equity per the Settlement Agreement							10.00%	10.00%
Requested Annual Increase									5,000,000	5,000,000
Additional Requested Annual Increase									15,000,000	15,000,000
Requested Total Annual Increase									20,000,000	20,000,000
Projected Capital Costs																			600,000,000	600,000,000													410,000,000	410,000,000
Construction Work in Progress	3,283,000,000	2,471,000,000	158,716,000	175,890,000	395,740,000	281,849,000													112,000,000	112,000,000
Contractual Construction Obligations																			84,000,000	84,000,000
Requested Base Rate Increase											38,000,000	38,000,000
Requested Return on Equity											10.50%	10.50%
Proposed Depreciation Increase Included in Requested Rate Increase											29,000,000	29,000,000
Year One Revenues Related to Proposed Recovery of Advanced Metering Costs											7,000,000	7,000,000
Year Three Revenues Related to Proposed Recovery of Advanced Metering Costs											28,000,000	28,000,000
Intervenor Recommended Reduction to the Requested Increase in Annual Base Rate											16,000,000	16,000,000
Intervenor Recommended Reduction in Annual Base Rates											22,000,000	22,000,000
Intervenor Recommended Return on Common Equity Range																							9.18%	9.18%			9.50%	9.50%
Revised Requested Base Rate Increase											42,000,000	42,000,000
2014 Revenues Related to Advanced Metering Costs as Proposed in Stipulation Agreement											7,000,000	7,000,000
2016 Revenues Related to Advanced Metering Costs as Proposed in Stipulation Agreement											$ 27,000,000	$ 27,000,000
Return on Common Equity for AFUDC and Factoring as Proposed in Stipulation Agreement											9.85%	9.85%