Other Income and Expenses (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other income:
Equity Available Funds Used During Construction	$ 96	$ 100	$ 116
Increase in cash surrender value of life insurance policies	26	25	23
Energy settlement	2	5	9
Other	11	11	12
Total utility other income	135	141	160
Competitive power generation and other income	21	7	11
Total other income	156	148	171
Other expenses:
Civic, political and related activities and donations	30	28	28
Marketing services	7	7	11
Other	18	16	10
Total utility other expenses	55	51	49
Competitive power generation and other expenses	0	0	8
Total other expenses	55	51	57
Non-cash accounting benefit on transfer of assets by Mountainview Power Company, LLC			46
Equity AFUDC recognized for Mountainview Power Plant Transfer			$ 50