Income Taxes (Components of Income Tax Expense (Benefit) by Location) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (221)	$ (46)	$ 18
State	4	33	19
Total current	(217)	(13)	37
Deferred:
Federal	570	176	340
State	(72)	14	109
Total deferred	498	190	449
Total continuing operations	281	177	486
Discontinued operations	0	(11)	(21)
Total	281	166	465
SCE
Current:
Federal	(253)	75	72
State	(81)	93	127
Total current	(334)	168	199
Deferred:
Federal	265	112	298
State	39	(24)	10
Total deferred	304	88	308
Total continuing operations	(30)	256	507
Discontinued operations	0	0	0
Total	$ (30)	$ 256	$ 507