Other Income and Expenses (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Other income:
Equity AFUDC	$ 27	$ 25	$ 56	$ 54
Increase in cash surrender value of life insurance policies	7	6	13	12
Other	5	4	8	4
Total utility other income	39	35	77	70
Competitive power generation and other income	3	1	6
Total other income	42	36	83	70
Other expenses:
Civic, political and related activities and donations	9	9	15	15
Other	4	6	10	11
Total utility other expenses	13	15	25	26
Competitive power generation and other expenses		1		2
Total other expenses	$ 13	$ 16	$ 25	$ 28