Other Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2009 Synthetic fuels matters	Jun. 30, 2012 Spent nuclear fuel matters	Jun. 30, 2012 Spent nuclear fuel matters PEC	Jun. 30, 2012 Spent nuclear fuel matters PEF
Gain Contingencies [Line Items]
Gain contingency, asserted damage		$ 113	$ 113	$ 113
Loss Contingencies [Line Items]
Judgment award	78
Prejudgment interest	55
Total judgment	133
After-tax loss contingency, loss in period	74
Judgment payment	$ 154