Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Increase (Decrease) in Accumulated Other Comprehensive Loss
Balance at the beginning of period	$ (87)
Net current-period other comprehensive loss	0		21
Balance at the end of period	(87)
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Abstract]
Tax expense	(98)		(91)
Total reclassification, net of tax	298		112
Southern California Edison
Increase (Decrease) in Accumulated Other Comprehensive Loss
Balance at the beginning of period	(29)
Net current-period other comprehensive loss	(3)		3
Balance at the end of period	(32)
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Abstract]
Tax expense	(112)		(99)
Total reclassification, net of tax	283		201
Accumulated Defined Benefit Plans Adjustment
Increase (Decrease) in Accumulated Other Comprehensive Loss
Balance at the beginning of period	(87)
Other comprehensive loss before reclassifications	(2)
Amounts reclassified from accumulated other comprehensive loss	2	[1]
Net current-period other comprehensive loss	0
Balance at the end of period	(87)
Accumulated Defined Benefit Plans Adjustment | Southern California Edison
Increase (Decrease) in Accumulated Other Comprehensive Loss
Balance at the beginning of period	(29)
Other comprehensive loss before reclassifications	(4)
Amounts reclassified from accumulated other comprehensive loss	1	[1]
Net current-period other comprehensive loss	(3)
Balance at the end of period	(32)
Accumulated Defined Benefit Plans Adjustment | Reclassification out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Abstract]
Amortization of net loss included in net income	3
Tax expense	1
Total reclassification, net of tax	2
Accumulated Defined Benefit Plans Adjustment | Reclassification out of Accumulated Other Comprehensive Loss | Southern California Edison
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Abstract]
Amortization of net loss included in net income	2
Tax expense	1
Total reclassification, net of tax	$ 1

[1] These items are included in the computation of net periodic pension and PBOP expense. See Note 8 for additional information.