Leases (Balance Sheet) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating leases:
Operating lease right-of-use assets	$ 1,532		$ 1,088
Current portion of operating lease liabilities	355		215
Operating lease liabilities	$ 1,177		$ 873
Finance leases included in:
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Public Utilities, Property, Plant and Equipment, Net		Public Utilities, Property, Plant and Equipment, Net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other Liabilities, Current		Other Liabilities, Current
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other Liabilities, Noncurrent		Other Liabilities, Noncurrent
SCE
Operating leases:
Operating lease right-of-use assets	$ 1,525		$ 1,085
Current portion of operating lease liabilities	355		214
Operating lease liabilities	1,170		871
Total operating lease liabilities	1,525		1,085
Finance leases included in:
Utility property, plant and equipment, gross	4		4
Accumulated depreciation	(1)
Utility property, plant and equipment, net	3		4
Other long-term liabilities	3		4
Total finance lease liabilities	3		$ 4
SCE | PPA Operating Leases
Operating leases:
Total operating lease liabilities	1,336
Finance leases included in:
ROU assets obtained in exchange for lease obligations	610	$ 463
SCE | Other Operating Leases
Operating leases:
Total operating lease liabilities	189
Finance leases included in:
ROU assets obtained in exchange for lease obligations	$ 38	$ 42