Nuclear Decommissioning Trust Fund Investments (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Of Securities In Nuclear Decommissioning Trust Fund

Security Type	Cost			Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
2011:
Debt securities	$	114		$	7	$	(a	)	$	121
Equity securities		145			101		12			234
Cash		3			—		—			3
Other(b)		(1	)		—		—			(1	)
Total	$	261		$	108	$	12		$	357
2010:
Debt securities	$	104		$	4	$	1		$	107
Equity securities		141			95		8			228
Cash		1			—		—			1
Other(b)		1			—		—			1
Total	$	247		$	99	$	9		$	337

(a) Amount less than $1 million.

(b) Represents payables relating to pending security purchases, net of receivables related to pending securities sales and interest receivables.

Schedule Of Unrealized Losses On Available-For-Sale Investments Included In Nuclear Decommissioning Trust Fund

	Less than 12 Months					12 Months or Greater						Total
	Fair Value		Gross Unrealized Losses			Fair Value			Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Debt securities	$	7	$	(a	)	$	(a	)	$	(a	)	$	7	$	(a	)
Equity securities		18		4			8			8			26		12
Total	$	25	$	4		$	8		$	8		$	33	$	12

(a) Amount less than $1 million.

Regulatory Asset [Member]

Proceeds From Sale Of Investments In Nuclear Decommissioning Trust Fund And Gross Realized Gains And Losses

	2011		2010		2009
Proceeds from sales	$	199	$	256	$	380
Gross realized gains		5		5		5
Gross realized losses		4		4		10

Fair Value Of Securities In Nuclear Decommissioning Trust Fund According To Their Contractual Maturities

	Cost		Fair Value
Less than 5 years	$	57	$	59
5 years to 10 years		34		36
Due after 10 years		23		26
Total	$	114	$	121