Leases (Supplemental Balance Sheet Information) (Details) $ in Millions	3 Months Ended
	Sep. 30, 2020 USD ($) contract	Dec. 31, 2019 USD ($)
Operating leases:
Operating lease right-of-use assets	$ 1,112	$ 693
Current portion of operating lease liabilities	210	80
Operating lease liabilities	902	613
Southern California Edison
Operating leases:
Operating lease right-of-use assets	1,109	689
Current portion of operating lease liabilities	210	79
Operating lease liabilities	899	610
Total operating lease liabilities	1,109	689
Finance leases included in:
Utility property, plant and equipment, gross	10	14
Accumulated depreciation	(1)	(5)
Utility property, plant and equipment, net	9	9
Other current liabilities	1	1
Other long-term liabilities	8	8
Total finance lease liabilities	$ 9	$ 9
Number of power contracts amended | contract	1
Reduction in ROU assets	$ (463)
Reduction in lease liabilities	$ (463)