Consolidated Statements of Operations (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Revenues	$ 5,291	$ 5,152	$ 4,993
Operating Expenses
Fuel, purchased power and gas	1,758	1,716	1,580
Operation and maintenance	1,429	1,369	1,305
Depreciation, depletion and amortization	822	813	849
Taxes other than income	256	240	237
Asset (gains) losses and reserves, net	(2)	12	(6)
Total operating expenses	4,263	4,150	3,965
Operating Income	1,028	1,002	1,028
Other (Income) and Deductions
Interest expense	272	289	313
Interest income	(1)	0	(1)
Other income	(53)	(47)	(39)
Other expenses	42	56	44
Total Other (Income) and Deductions	260	298	317
Income Before Income Taxes	768	704	711
Income Tax Expense	282	267	270
Net Income	$ 486	$ 437	$ 441