XML 113 R37.htm IDEA: XBRL DOCUMENT v2.3.0.15
Organization (Details) (USD $)
In Millions
3 Months Ended9 Months Ended
Sep. 30, 2011
Sep. 30, 2010
Sep. 30, 2011
Sep. 30, 2010
Operating income$ 195$ 212$ 546$ 536
Proceeds from sale of power generation business   1,635
Subsidiary of Common Parent [Member] | Retail Energy Service Business [Member]
    
Operating revenue2173777531,275
Operating income5152145
Letters of credit1 1 
Posted cash collateral$ 116 $ 116