Other Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2009 Synthetic Fuels Matters [Member]	Sep. 30, 2012 Spent Nuclear Fuel Matters [Member]	Sep. 30, 2012 Spent Nuclear Fuel Matters [Member] PEC [Member]	Sep. 30, 2012 Spent Nuclear Fuel Matters [Member] PEF [Member]
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