Compensation and Benefit Plans (Other Postretirement Plan Assets - Fair Value Levels) (Details) - Postretirement Benefits Other Than Pensions - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets		$ 2,036	$ 2,086	$ 2,065
Undervalued Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation percentage of US equity securities		17.00%
Collateralized mortgage obligations and other asset backed securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Receivables and payables, net		$ 27	31
Municipal Notes
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		$ 97	111
Russell 200 and Russell 1000 indexes | Corporate stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Performance percentage benchmark, percentage		47.00%
Russell 1000 index | Common or collective equity funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Performance percentage benchmark, percentage		38.00%
Morgan Stanley Capital International Europe Australasia And Far East Index | Equity index fund
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Performance percentage benchmark, percentage		41.00%
MSCI All Country World Index | Corporate stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Performance percentage benchmark, percentage		53.00%
Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets		$ 74	$ 105	164
Level 3 | Asset backed securities including distressed mortgages
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual plan asset allocations, percentage		29.00%	50.00%
Level 3 | Private Equity Funds Including Branded Consumer Products, Clean Technology and California Geographic Focus Companies
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual plan asset allocations, percentage		71.00%	50.00%
Southern California Edison
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		$ 2,060	$ 2,159
Receivables and payables, net		(24)	(73)
Fair Value of Plan Assets		2,036	2,086	$ 2,065
Southern California Edison | Common/collective funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[1]	424	431
Southern California Edison | Corporate stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[2]	222	250
Southern California Edison | Corporate notes and bonds securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[3]	867	883
Southern California Edison | Partnerships/joint ventures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[4]	93	124
Southern California Edison | U.S. government and agency securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[5]	242	243
Southern California Edison | Registered investment companies
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[6]	63	69
Southern California Edison | Interest bearing cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		31	29
Southern California Edison | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[7]	118	130
Southern California Edison | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		518	555
Southern California Edison | Level 1 | Common/collective funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[1]	0	0
Southern California Edison | Level 1 | Corporate stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[2]	222	250
Southern California Edison | Level 1 | Corporate notes and bonds securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[3]	0	0
Southern California Edison | Level 1 | Partnerships/joint ventures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[4]	0	0
Southern California Edison | Level 1 | U.S. government and agency securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[5]	200	207
Southern California Edison | Level 1 | Registered investment companies
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[6]	60	64
Southern California Edison | Level 1 | Interest bearing cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		31	29
Southern California Edison | Level 1 | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[7]	5	5
Southern California Edison | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		1,469	1,499
Southern California Edison | Level 2 | Common/collective funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[1]	424	431
Southern California Edison | Level 2 | Corporate stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[2]	0	0
Southern California Edison | Level 2 | Corporate notes and bonds securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[3]	867	883
Southern California Edison | Level 2 | Partnerships/joint ventures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[4]	20	19
Southern California Edison | Level 2 | U.S. government and agency securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[5]	42	36
Southern California Edison | Level 2 | Registered investment companies
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[6]	3	5
Southern California Edison | Level 2 | Interest bearing cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		0	0
Southern California Edison | Level 2 | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[7]	113	125
Southern California Edison | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		73	105
Southern California Edison | Level 3 | Common/collective funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[1]	0	0
Southern California Edison | Level 3 | Corporate stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[2]	0	0
Southern California Edison | Level 3 | Corporate notes and bonds securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[3]	0	0
Southern California Edison | Level 3 | Partnerships/joint ventures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[4]	73	105
Southern California Edison | Level 3 | U.S. government and agency securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[5]	0	0
Southern California Edison | Level 3 | Registered investment companies
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[6]	0	0
Southern California Edison | Level 3 | Interest bearing cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross		0	0
Southern California Edison | Level 3 | Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets, Gross	[7]	$ 0	$ 0

[1] At both December 31, 2015 and 2014, 38% of the common/collective assets are invested in a large cap index fund which seeks to track performance of the Russell 1000 index. 41% of the assets in this category are in index funds which seek to track performance in the MSCI All Country World Index Investable Market Index and MSCI Europe, Australasia and Far East (EAFE) Index. 17% in a non-index U.S. equity fund which is actively managed.

[2] Corporate stock performance for actively managed separate accounts is primarily benchmarked against the Russell Indexes (47%) and the MSCI All Country World Index (53%) for both 2015 and 2014.

[3] Corporate notes and bonds are diversified and include approximately $27 million and $31 million for commercial collateralized mortgage obligations and other asset backed securities at December 31, 2015 and 2014, respectively.

[4] At December 31, 2015 and 2014, respectively, 29% and 50% of the Level 3 partnerships category is invested in (1) asset backed securities including distressed mortgages, (2) distressed companies and (3) commercial and residential loans and debt and equity of banks. At December 31, 2015 and 2014, respectively, 71% and 50% of the Level 3 partnerships are invested in private equity and venture capital funds. Investment strategies for these funds include branded consumer products, clean and information technology and healthcare.

[5] Level 1 U.S. government and agency securities are U.S. treasury bonds and notes. Level 2 primarily relates to the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association.

[6] Level 1 registered investment companies consist of a money market fund.

[7] Other includes $97 million and $111 million of municipal securities at December 31, 2015 and 2014, respectively.