Available-For-Sale Securities (Narrative) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended			3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Nuclear Decommissioning Trust (NDT) Fund [Member]	Mar. 31, 2012 Nuclear Decommissioning Trust (NDT) Fund [Member] Power [Member] Debt Securities [Member]	Mar. 31, 2012 Rabbi Trust Fund [Member]	Mar. 31, 2012 Rabbi Trust Fund [Member] Power [Member] Debt Securities [Member]
Schedule of Available-for-Sale Securities [Line Items]
After tax amount of net unrealized gains recognized in AOCI				$ 104		$ 3
Amount of other-than-temporary impairments			5
Accounts receivable	47	27			1
Accounts payable	$ 49	$ 22			$ 51