Consolidated Statements of Operations (Unaudited) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Income Statement [Abstract]
Operating Revenues	$ 1,517	$ 1,444	$ 3,949	$ 3,798
Operating Expenses
Fuel and purchased power	553	484	1,348	1,217
Operation and maintenance	352	325	1,012	960
Depreciation and amortization	215	230	619	644
Taxes other than income	63	54	182	180
Asset (gains) and losses, net	(1)	0	13	(1)
Total operating expenses	1,182	1,093	3,174	3,000
Operating Income	335	351	775	798
Other (Income) and Deductions
Interest expense	74	83	218	241
Interest income	0	(1)	0	(1)
Other income	(9)	(10)	(30)	(27)
Other expenses	14	6	26	23
Total Other (Income) and Deductions	79	78	214	236
Income Before Income Taxes	256	273	561	562
Income Tax Expense	98	108	214	219
Net Income	$ 158	$ 165	$ 347	$ 343