REGULATORY, General Rate Cases (Details) (GRC [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
SPPC Electric
Summary of General Rate Case [Line Items]
Anticipated Effective Date of Rate Filing	January 1, 2014
Requested Increase Decrease In General Rates	$ (4.7)
Percentage Overall Increase Decrease In General Rates	(0.70%)
Requested Rate Of Return	7.74%
Requested Return On Equity	10.40%
General Rate Case Hearing Date	October 2013
SPPC Gas
Summary of General Rate Case [Line Items]
Anticipated Effective Date of Rate Filing	January 1, 2014
Requested Increase Decrease In General Rates	$ 6.0
Percentage Overall Increase Decrease In General Rates	6.10%
Requested Rate Of Return	7.72%
Requested Return On Equity	10.35%
General Rate Case Hearing Date	October 2013