Consolidated Statements of Operations (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Operating Revenues	$ 1,357	$ 1,457	$ 4,048	$ 3,941
Operating Expenses
Fuel and purchased power	430	487	1,328	1,294
Operation and maintenance	351	335	1,022	1,009
Depreciation and amortization	238	233	695	666
Taxes other than income	66	67	202	200
Asset (gains) losses and reserves, net	0	(3)	(1)	(3)
Total Operating Expenses	1,085	1,119	3,246	3,166
Operating Income	272	338	802	775
Other (Income) and Deductions
Interest expense	65	68	189	202
Other income	(15)	(14)	(45)	(38)
Other expenses	11	7	26	19
Total Other (Income) and Deductions	61	61	170	183
Income Before Income Taxes	211	277	632	592
Income Tax Expense	75	97	229	206
Net Income	$ 136	$ 180	$ 403	$ 386