Commitments and Contingencies (Schedule of Settlement Agreement) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Total pre-tax charge			$ 78	$ 738	$ 21
SCE
Loss Contingencies [Line Items]
Total pre-tax charge			$ (12)	716	$ 0
Total after-tax charge	$ 448			448
SCE | Utility Shareholder Agreement
Loss Contingencies [Line Items]
Total pre-tax charge				143
SCE | Revised San Onofre settlement agreement
Loss Contingencies [Line Items]
Total pre-tax charge		$ 716
SCE | DOE litigation regulatory liability
Loss Contingencies [Line Items]
Total pre-tax charge				(72)
SCE | Arbitration with Mitsubishi Heavy Industries
Loss Contingencies [Line Items]
Total pre-tax charge				(47)
SCE | GHG Reduction Program
Loss Contingencies [Line Items]
Total pre-tax charge				(10)
SCE | San Onofre base regulatory asset
Loss Contingencies [Line Items]
Total pre-tax charge				696
SCE | Other
Loss Contingencies [Line Items]
Total pre-tax charge				$ 6
Settled litigation | The Utilities | Revised San Onofre settlement agreement
Loss Contingencies [Line Items]
Funding obligation	$ 10