Borrowings and Other Financing Instruments,Other Short-Term Borrowings (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Short-term Debt [Line Items]
Notes payable to affiliates	$ 470	$ 550
Notes Payable, Other Payables
Short-term Debt [Line Items]
Notes payable to affiliates	$ 500	$ 600
Weighted average interest rate at period end (in hundredths)	0.24%	0.33%