Nuclear Decommissioning Trust Fund Investments (Fair Values Of Investments In Debt And Equity Securities In Nuclear Decommissioning Trust Fund) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Nuclear Decommissioning Trust Fund Investments [Line Items]
Cost	$ 297,000,000	$ 281,000,000
Gross unrealized gains	203,000,000	138,000,000
Gross unrealized loss	6,000,000	11,000,000
Fair Value	494,000,000	408,000,000
Debt Securities
Nuclear Decommissioning Trust Fund Investments [Line Items]
Cost	157,000,000	133,000,000
Gross unrealized gains	4,000,000	8,000,000
Gross unrealized loss	2,000,000
Fair Value	159,000,000	141,000,000
Equity Securities
Nuclear Decommissioning Trust Fund Investments [Line Items]
Cost	137,000,000	145,000,000
Gross unrealized gains	199,000,000	130,000,000
Gross unrealized loss	4,000,000	11,000,000
Fair Value	332,000,000	264,000,000
Cash
Nuclear Decommissioning Trust Fund Investments [Line Items]
Cost	3,000,000	1,000,000
Fair Value	3,000,000	1,000,000
Other Debt And Equity Securities
Nuclear Decommissioning Trust Fund Investments [Line Items]
Cost		2,000,000	[1]
Fair Value		$ 2,000,000	[1]

[1] Represents payables relating to pending security purchases, net of receivables related to pending security sales and interest receivables.