Long-Term Debt (Details Textuals) (Electric [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Thirty Years [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	$ 150
Future Debt Instrument, Interest Rate, Stated Percentage	4.60%
Twelve Years [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount, Future Issuance	100
Future Debt Instrument, Interest Rate, Stated Percentage	3.77%
Final Maturity of 2024 [Member]
Debt Instrument [Line Items]
Future Extinguishment of Debt, Amount	31
Debt Instrument, Interest Rate, Stated Percentage	2.35%
Final Maturity of 2028 [Member]
Debt Instrument [Line Items]
Future Extinguishment of Debt, Amount	$ 32
Debt Instrument, Interest Rate, Stated Percentage	4.65%