Fair Value Measurements (Fair Value by Level) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Assets at Fair Value
Nuclear decommissioning trusts	$ 4,494		$ 4,048
Liabilities at Fair Value
Money market funds	68		107
Level 1
Liabilities at Fair Value
Money market funds	68		107
Southern California Edison
Assets at Fair Value
Nuclear decommissioning trusts	4,494		4,048		3,592	3,480
Liabilities at Fair Value
Percentage of equity investments located in the United States (as a percent)	70.00%		66.00%
Collateralized mortgage obligations and other asset backed securities	47		56
Receivables (payables) net related to investments	12		(1)
Money market funds	8		5
Southern California Edison | Stocks
Assets at Fair Value
Nuclear decommissioning trusts	2,208		2,271
Southern California Edison | Fair Value, Measurements, Recurring | Level 1
Assets at Fair Value
Derivative contracts	0		0
Other	39		13
Nuclear decommissioning trusts	3,380	[1]	2,869	[1]
Total assets	3,419		2,882
Liabilities at Fair Value
Derivative contracts	0		0
Total liabilities	0		0
Net assets (liabilities)	3,419		2,882
Southern California Edison | Fair Value, Measurements, Recurring | Level 1 | Stocks
Assets at Fair Value
Nuclear decommissioning trusts	2,208	[2]	2,271	[2]
Southern California Edison | Fair Value, Measurements, Recurring | Level 1 | Fixed Income Securities [Member]
Assets at Fair Value
Nuclear decommissioning trusts	841	[3]	477	[3]
Southern California Edison | Fair Value, Measurements, Recurring | Level 1 | Short-term investments, primarily cash equivalents
Assets at Fair Value
Nuclear decommissioning trusts	331		121	[1]
Southern California Edison | Fair Value, Measurements, Recurring | Level 2
Assets at Fair Value
Derivative contracts	11		8
Other	0		0
Nuclear decommissioning trusts	1,102	[1]	1,180	[1]
Total assets	1,113		1,188
Liabilities at Fair Value
Derivative contracts	37		115
Total liabilities	37		115
Net assets (liabilities)	1,076		1,073
Southern California Edison | Fair Value, Measurements, Recurring | Level 2 | Stocks
Assets at Fair Value
Nuclear decommissioning trusts	0	[2]	0	[2]
Southern California Edison | Fair Value, Measurements, Recurring | Level 2 | Fixed Income Securities [Member]
Assets at Fair Value
Nuclear decommissioning trusts	1,102	[3]	1,180	[3]
Southern California Edison | Fair Value, Measurements, Recurring | Level 2 | Short-term investments, primarily cash equivalents
Assets at Fair Value
Nuclear decommissioning trusts	0		0	[1]
Southern California Edison | Fair Value, Measurements, Recurring | Level 3
Assets at Fair Value
Derivative contracts	372		221
Other	0		0
Nuclear decommissioning trusts	0	[1]	0	[1]
Total assets	372		221
Liabilities at Fair Value
Derivative contracts	1,177		1,012
Total liabilities	1,177		1,012
Net assets (liabilities)	(805)		(791)
Southern California Edison | Fair Value, Measurements, Recurring | Level 3 | Stocks
Assets at Fair Value
Nuclear decommissioning trusts	0	[2]	0	[2]
Southern California Edison | Fair Value, Measurements, Recurring | Level 3 | Fixed Income Securities [Member]
Assets at Fair Value
Nuclear decommissioning trusts	0	[3]	0	[3]
Southern California Edison | Fair Value, Measurements, Recurring | Level 3 | Short-term investments, primarily cash equivalents
Assets at Fair Value
Nuclear decommissioning trusts	0		0	[1]
Southern California Edison | Fair Value, Measurements, Recurring | Netting and Collateral
Assets at Fair Value
Derivative contracts	(10)	[4]	(15)	[4]
Other	0		0
Nuclear decommissioning trusts	0	[1],[4]	0	[1],[4]
Total assets	(10)	[4]	(15)	[4]
Liabilities at Fair Value
Derivative contracts	(20)	[4]	(62)	[4]
Total liabilities	(20)	[4]	(62)	[4]
Net assets (liabilities)	10	[4]	47	[4]
Southern California Edison | Fair Value, Measurements, Recurring | Netting and Collateral | Stocks
Assets at Fair Value
Nuclear decommissioning trusts	0	[2],[4]	0	[2],[4]
Southern California Edison | Fair Value, Measurements, Recurring | Netting and Collateral | Fixed Income Securities [Member]
Assets at Fair Value
Nuclear decommissioning trusts	0	[3]	0	[3]
Southern California Edison | Fair Value, Measurements, Recurring | Netting and Collateral | Short-term investments, primarily cash equivalents
Assets at Fair Value
Nuclear decommissioning trusts	0	[4]	0	[1],[4]
Southern California Edison | Fair Value, Measurements, Recurring | Total
Assets at Fair Value
Derivative contracts	373		214
Other	39		13
Nuclear decommissioning trusts	4,482	[1]	4,049	[1]
Total assets	4,894		4,276
Liabilities at Fair Value
Derivative contracts	1,194		1,065
Total liabilities	1,194		1,065
Net assets (liabilities)	3,700		3,211
Southern California Edison | Fair Value, Measurements, Recurring | Total | Stocks
Assets at Fair Value
Nuclear decommissioning trusts	2,208	[2]	2,271	[2]
Southern California Edison | Fair Value, Measurements, Recurring | Total | Fixed Income Securities [Member]
Assets at Fair Value
Nuclear decommissioning trusts	1,943	[3]	1,657	[3]
Southern California Edison | Fair Value, Measurements, Recurring | Total | Short-term investments, primarily cash equivalents
Assets at Fair Value
Nuclear decommissioning trusts	$ 331		$ 121	[1]

[1] Excludes net receivables of $12 million at December 31, 2013 and net payables of $1 million at December 31, 2012, which consist of interest and dividend receivables as well as receivables and payables related to SCE's pending securities sales and purchases.

[2] Approximately 70% and 66% of SCE's equity investments were located in the United States at December 31, 2013 and 2012, respectively.

[3] corporate bonds, which were diversified and included collateralized mortgage obligations and other asset backed securities of $47 million and $56 million at December 31, 2013 and 2012, respectively.

[4] Represents the netting of assets and liabilities under master netting agreements and cash collateral across the levels of the fair value hierarchy. Netting among positions classified within the same level is included in that level.