Organization, Basis Of Presentation And Summary Of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Operating Revenues	$ 2,773	$ 2,641	$ 2,249	$ 3,223	$ 2,318	$ 2,554	$ 2,310	$ 2,786	$ 10,886	$ 9,968	$ 9,781
Basis Adjustment	986								986
Net Income									1,518	1,243	1,275
Total Assets	35,333				32,522				35,333	32,522
Power [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Operating Revenues	1,610	1,138	986	1,700	1,245	1,174	1,193	1,451	5,434	5,063	4,873
Basis Adjustment	(986)				(986)				(986)	(986)
Net Income									760	644	666
Total Assets	$ 12,046				$ 12,002				$ 12,046	$ 12,002
Power [Member] | Nuclear Production [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									60 years
Power [Member] | Pumped Storage Facilities [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									76 years
Power [Member] | Solar Assets [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									25 years
Power [Member] | Minimum [Member] | General Plant Assets [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									3 years
Power [Member] | Minimum [Member] | Fossil Production [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									19 years
Power [Member] | Maximum [Member] | General Plant Assets [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									20 years
Power [Member] | Maximum [Member] | Fossil Production [Member]
Organization Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives									79 years