Commitments And Contingent Liabilities (Minimum Fuel Purchase Requirements) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2011
Long-term Purchase Commitment [Line Items]
Total minimum purchase requirements	$ 896
Power [Member] | Commitments Through 2015 [Member] | Nuclear Fuel Uranium [Member]
Long-term Purchase Commitment [Line Items]
Total minimum purchase requirements	493
Power [Member] | Commitments Through 2015 [Member] | Nuclear Fuel Enrichment [Member]
Long-term Purchase Commitment [Line Items]
Total minimum purchase requirements	383
Power [Member] | Commitments Through 2015 [Member] | Nuclear Fuel Fabrication [Member]
Long-term Purchase Commitment [Line Items]
Total minimum purchase requirements	130
Power [Member] | Commitments Through 2015 [Member] | Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Total minimum purchase requirements	903
Power [Member] | Commitments Through 2015 [Member] | Coal/Oil [Member]
Long-term Purchase Commitment [Line Items]
Total minimum purchase requirements	896
Power [Member]
Long-term Purchase Commitment [Line Items]
Coverage percentage of nuclear fuel commitments of uranium, enrichment, and fabrication requirements	100.00%
Amount of coal / oil commitments Power can cancel at no cost	$ 647