Consolidated Statements of Operations (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating revenue	$ 5,252	$ 5,147	$ 4,882
Operating costs and expenses:
Energy costs	1,997	1,924	1,818
Operations and maintenance	1,057	1,114	1,242
Depreciation and amortization	726	675	640
Taxes, other than income taxes	172	170	161
Total operating costs and expenses	3,952	3,883	3,861
Operating income	1,300	1,264	1,021
Other income (expense):
Interest expense	(379)	(379)	(380)
Allowance for borrowed funds	25	29	29
Allowance for equity funds	51	57	58
Other, net	10	8	6
Total other income (expense)	(293)	(285)	(287)
Income before income tax expense	1,007	979	734
Income tax expense	309	297	197
Net income	$ 698	$ 682	$ 537