Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits
Balance at January 1,	$ 432	$ 471	$ 529
Tax positions taken during the current year, Increases	41	51	36
Tax positions taken during a prior year, Increases	0	0	2
Tax positions taken during a prior year, Decreases	(108)	(7)	(96)
Tax positions taken during a prior year, Decreases for settlements during the period	(27)	(83)	0
Balance at December 31,	338	432	471
SCE
Reconciliation of Unrecognized Tax Benefits
Balance at January 1,	331	371	353
Tax positions taken during the current year, Increases	42	51	36
Tax positions taken during a prior year, Increases	0	0	0
Tax positions taken during a prior year, Decreases	(121)	(13)	(18)
Tax positions taken during a prior year, Decreases for settlements during the period	(3)	(78)	0
Balance at December 31,	$ 249	$ 331	$ 371