Leases (Supplemental Balance Sheet Information) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) contract	Dec. 31, 2019 USD ($)
Operating leases:
Operating lease right-of-use ("ROU") assets	$ 1,088	$ 693
Current portion of operating lease liabilities	215	80
Operating lease liabilities	$ 873	$ 613
Finance leases included in:
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet	us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
SCE
Operating leases:
Operating lease right-of-use ("ROU") assets	$ 1,085	$ 689
Current portion of operating lease liabilities	214	79
Operating lease liabilities	871	610
Total operating lease liabilities1	1,085	689
Finance leases included in:
Utility property, plant and equipment, gross	4	14
Accumulated depreciation	0	(5)
Utility property, plant and equipment, net	4	9
Other current liabilities	0	1
Other long-term liabilities	4	8
Total finance lease liabilities	$ 4	9
Number of power contracts amended | contract	1
PPA operating leases	$ 463	$ 0