Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 80	$ 47
Accounts receivable, net	671	653
Income taxes receivable	0	70
Inventories:
Materials and supplies	202	196
Fuel	266	237
Deferred income taxes	112	129
Regulatory assets	62	74
Other current assets	75	77
Total current assets	1,468	1,483
Property, plant and equipment, net	18,057	17,374
Regulatory assets	1,773	1,810
Other assets	430	439
Total assets	21,728	21,106
Current liabilities:
Accounts payable	467	582
Income taxes payable	48	0
Accrued employee expenses	77	72
Accrued interest	113	105
Accrued property and other taxes	54	66
Derivative contracts	49	90
Short-term debt	0	688
Current portion of long-term debt and capital lease obligations	267	19
Regulatory liabilities	62	67
Other current liabilities	147	125
Total current liabilities	1,284	1,814
Regulatory liabilities	851	826
Long-term debt and capital lease obligations	6,594	6,194
Deferred income taxes	4,168	3,863
Other long-term liabilities	1,187	1,097
Total liabilities	14,084	13,794
Commitments and contingencies (Note 13)
Shareholders' equity:
Preferred stock	41	41
Common stock - 750 shares authorized, no par value, 357 shares issued and outstanding	0	0
Additional paid-in capital	4,479	4,479
Retained earnings	3,136	2,801
Accumulated other comprehensive loss, net	(12)	(9)
Total shareholders' equity	7,644	7,312
Total liabilities and shareholders' equity	$ 21,728	$ 21,106