Segment Information (Inter-segment billing) (Details) (Intersegment Eliminations [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Inter-Segment Revenue [Line Items]
Revenue, Net	$ 868	$ 848	$ 301
Electric [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	26	29	33
Gas [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	4	4	2
Gas Storage and Pipelines [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	3	6	8
Power and Industrial Projects [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	816	801	238
Energy Trading [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	43	43	70
Corporate and Other [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	(24)	(37)	(50)
Discontinued Operations [Member]
Inter-Segment Revenue [Line Items]
Revenue, Net	$ 0	$ 2	$ 0