Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ (9,000)	$ (8,548)
Total utility property, plant and equipment	36,806	34,945
SCE
Property, Plant and Equipment [Line Items]
Distribution	22,332	20,871
Transmission	12,549	11,592
Generation	3,376	3,138
General plant and other	4,633	4,543
Accumulated depreciation	(9,000)	(8,548)
Total utility property, plant and equipment, Gross	33,890	31,596
Construction work in progress	2,790	3,218
Nuclear fuel, at amortized cost	126	131
Total utility property, plant and equipment	$ 36,806	$ 34,945