SONGS NDT 1 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 649								$ 627
Gross Unrealized Gains	444								417
Gross Unrealized Loss	(6)								(10)
Estimated Fair Value	1,087								1,034
Proceeds from sales	148	[1]	181	[1]	498	[1]	507	[1]
Gross realized gains	5		2		9		13
Gross realized losses	(3)		(8)		(8)		(15)
Total Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	411								381
Gross Unrealized Gains	17								8
Gross Unrealized Loss	(4)								(8)
Estimated Fair Value	424								381
Debt Securities Issued By The U.S. Treasury And Other U.S. Government Corporations And Agencies
Schedule of Available-for-sale Securities [Line Items]
Cost	99	[2]							116
Gross Unrealized Gains	4	[2]							3
Gross Unrealized Loss	0	[2]							(2)
Estimated Fair Value	103	[2]							117
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	114	[3]							110
Gross Unrealized Gains	7	[3]							2
Gross Unrealized Loss	0	[3]							(1)
Estimated Fair Value	121	[3]							111
Other Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	198	[4]							155
Gross Unrealized Gains	6	[4]							3
Gross Unrealized Loss	(4)	[4]							(5)
Estimated Fair Value	200	[4]							153
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	212								207
Gross Unrealized Gains	427								409
Gross Unrealized Loss	(2)								(2)
Estimated Fair Value	637								614
Cash And Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Cost	26								39
Gross Unrealized Gains	0								0
Gross Unrealized Loss	0								0
Estimated Fair Value	$ 26								$ 39

[1] (1) Excludes securities that are held to maturity.

[2] Maturity dates are 2016-2060

[3] Maturity dates are 2014-2062

[4] Maturity dates are 2014-2096