Consolidated Statements of Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			$ 13,866	$ 14,187
Net income			543	702
Net income	$ 298	$ 309	540	701
Other comprehensive income			4
Other comprehensive income	2	1	(1)	5
Cumulative effect of accounting changes			5
Contributions from tax equity investor			24
Dividends declared on common stock			(394)	(354)
Dividends to noncontrolling interests			(60)	(62)
Stock-based compensation			(12)	(151)
Noncash stock-based compensation			11	10
Deconsolidation of SoCore Energy			(15)
Issuance of preference stock				463
Balance, at the end of the period	$ 13,972	$ 14,800	$ 13,972	$ 14,800
Dividends declared per common share (in dollars per share)	$ 0.6050	$ 0.5425	$ 1.2100	$ 1.0850
Common Stock Including Additional Paid in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			$ 2,526	$ 2,505
Net income			0	0
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			0
Dividends declared on common stock			0	0
Dividends to noncontrolling interests			0	0
Stock-based compensation			0	0
Noncash stock-based compensation			11	10
Deconsolidation of SoCore Energy			0
Issuance of preference stock				0
Balance, at the end of the period	$ 2,537	$ 2,515	2,537	2,515
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			(43)	(53)
Net income			0	0
Other comprehensive income			4
Other comprehensive income				5
Cumulative effect of accounting changes			(5)
Dividends declared on common stock			0	0
Dividends to noncontrolling interests			0	0
Stock-based compensation			0	0
Noncash stock-based compensation			0	0
Deconsolidation of SoCore Energy			0
Issuance of preference stock				0
Balance, at the end of the period	(44)	(48)	(44)	(48)
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			9,188	9,544
Net income			494	640
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			10
Dividends declared on common stock			(394)	(354)
Dividends to noncontrolling interests			0	0
Stock-based compensation			(12)	(151)
Noncash stock-based compensation			0	0
Deconsolidation of SoCore Energy			0
Issuance of preference stock				0
Balance, at the end of the period	9,286	9,679	9,286	9,679
Subtotal
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			11,671	11,996
Net income			494	640
Other comprehensive income			4
Other comprehensive income				5
Cumulative effect of accounting changes			5
Dividends declared on common stock			(394)	(354)
Dividends to noncontrolling interests			0	0
Stock-based compensation			(12)	(151)
Noncash stock-based compensation			11	10
Deconsolidation of SoCore Energy			0
Issuance of preference stock				0
Balance, at the end of the period	11,779	12,146	11,779	12,146
Noncontrolling Interests, Other
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2
Net income			(11)
Other comprehensive income			0
Cumulative effect of accounting changes			0
Contributions from tax equity investor			24
Dividends declared on common stock			0
Dividends to noncontrolling interests			0
Stock-based compensation			0
Noncash stock-based compensation			0
Deconsolidation of SoCore Energy			(15)
Balance, at the end of the period	0		0
Noncontrolling Interests, Preferred and Preference Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2,193	2,191
Net income			60	62
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			0
Dividends declared on common stock			0	0
Dividends to noncontrolling interests			(60)	(62)
Stock-based compensation			0	0
Noncash stock-based compensation			0	0
Deconsolidation of SoCore Energy			0
Issuance of preference stock				463
Balance, at the end of the period	2,193	2,654	2,193	2,654
Southern California Edison
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			14,672	14,483
Net income	327	338	643	718
Other comprehensive income			3
Other comprehensive income	1	0	(2)	2
Cumulative effect of accounting changes			0
Dividends declared on common stock			(312)	(382)
Dividends declared on preferred and preference stock			(60)	(62)
Stock-based compensation			(5)	(33)
Noncash stock-based compensation			5	6
Issuance of preference stock				463
Balance, at the end of the period	14,946	15,195	14,946	15,195
Southern California Edison | Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2,168	2,168
Net income			0	0
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			0
Dividends declared on common stock			0	0
Dividends declared on preferred and preference stock			0	0
Stock-based compensation			0	0
Noncash stock-based compensation			0	0
Issuance of preference stock				0
Balance, at the end of the period	2,168	2,168	2,168	2,168
Southern California Edison | Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			671	657
Net income			0	0
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			0
Dividends declared on common stock			0	0
Dividends declared on preferred and preference stock			0	0
Stock-based compensation			0	0
Noncash stock-based compensation			5	6
Issuance of preference stock				(12)
Balance, at the end of the period	676	651	676	651
Southern California Edison | Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			(19)	(20)
Net income			0	0
Other comprehensive income			3
Other comprehensive income				2
Cumulative effect of accounting changes			(5)
Dividends declared on common stock			0	0
Dividends declared on preferred and preference stock			0	0
Stock-based compensation			0	0
Noncash stock-based compensation			0	0
Issuance of preference stock				0
Balance, at the end of the period	(21)	(18)	(21)	(18)
Southern California Edison | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			9,607	9,433
Net income			643	718
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			5
Dividends declared on common stock			(312)	(382)
Dividends declared on preferred and preference stock			(60)	(62)
Stock-based compensation			(5)	(33)
Noncash stock-based compensation			0	0
Issuance of preference stock				0
Balance, at the end of the period	9,878	9,674	9,878	9,674
Southern California Edison | Preferred and Preference Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2,245	2,245
Net income			0	0
Other comprehensive income			0
Other comprehensive income				0
Cumulative effect of accounting changes			0
Dividends declared on common stock			0	0
Dividends declared on preferred and preference stock			0	0
Stock-based compensation			0	0
Noncash stock-based compensation			0	0
Issuance of preference stock				475
Balance, at the end of the period	$ 2,245	$ 2,720	$ 2,245	$ 2,720