Commitments And Contingencies (Third-Party Power Purchases) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Long-term Purchase Commitment [Line Items]
Total	$ 780	$ 53,300
Maximum [Member]
Long-term Purchase Commitment [Line Items]
Long-term agreements range, years	25