Consolidated Statements of Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period	$ 13,866	$ 14,187
Net income	245	393
Net income	242	392
Other comprehensive income	2
Other comprehensive income	(3)	4
Cumulative effect of accounting changes	5
Dividends declared on common stock	(197)	(177)
Dividends to noncontrolling interests	(30)	(31)
Stock-based compensation	(8)	(139)
Noncash stock-based compensation	5	5
Other	1
Balance, at the end of the period	$ 13,889	$ 14,242
Dividends declared per common share (in dollars per share)	$ 0.6050	$ 0.5425
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	5	5
Other	0
Balance, at the end of the period	2,531	2,510
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	2
Other comprehensive income		4
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
Other	0
Balance, at the end of the period	(46)	(49)
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period	9,188	9,544
Net income	218	362
Other comprehensive income	0
Other comprehensive income		0
Cumulative effect of accounting changes	10
Dividends declared on common stock	(197)	(177)
Dividends to noncontrolling interests	0	0
Stock-based compensation	(8)	(139)
Noncash stock-based compensation	0	0
Other	0
Balance, at the end of the period	9,211	9,590
Subtotal
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period	11,671	11,996
Net income	218	362
Other comprehensive income	2
Other comprehensive income		4
Cumulative effect of accounting changes	5
Dividends declared on common stock	(197)	(177)
Dividends to noncontrolling interests	0	0
Stock-based compensation	(8)	(139)
Noncash stock-based compensation	5	5
Other	0
Balance, at the end of the period	11,696	12,051
Noncontrolling Interests, Other
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period	2
Net income	(3)
Other comprehensive income	0
Cumulative effect of accounting changes	0
Dividends declared on common stock	0
Dividends to noncontrolling interests	0
Stock-based compensation	0
Noncash stock-based compensation	0
Other	1
Balance, at the end of the period	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	30	31
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	(30)	(31)
Stock-based compensation	0	0
Noncash stock-based compensation	0	0
Other	0
Balance, at the end of the period	2,193	2,191
Southern California Edison
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period	14,672	14,483
Net income	316	380
Other comprehensive income	2
Other comprehensive income	(3)	2
Cumulative effect of accounting changes	0
Dividends declared on common stock	(212)	(191)
Dividends declared on preferred and preference stock	(30)	(31)
Stock-based compensation	(2)	(23)
Noncash stock-based compensation	2
Redemption of preference stock		(3)
Balance, at the end of the period	14,748	14,623
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
Redemption of preference stock		0
Balance, at the end of the period	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	2
Redemption of preference stock		(3)
Balance, at the end of the period	673	660
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	2
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
Redemption of preference stock		0
Balance, at the end of the period	(22)	(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	316	380
Other comprehensive income	0
Other comprehensive income		0
Cumulative effect of accounting changes	5
Dividends declared on common stock	(212)	(191)
Dividends declared on preferred and preference stock	(30)	(31)
Stock-based compensation	(2)	(23)
Noncash stock-based compensation	0
Redemption of preference stock		0
Balance, at the end of the period	9,684	9,568
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
Redemption of preference stock		0
Balance, at the end of the period	$ 2,245	$ 2,245