Consolidated Statements of Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			$ 14,187	$ 13,388
Net income			1,204	1,074
Net income	$ 501	$ 451	1,202	1,065
Other comprehensive income (loss)	0	2	5	5
Dividends declared on common stock			(530)	(469)
Dividends to noncontrolling interests			(94)	(92)
Stock-based compensation			(165)	(31)
Non-cash stock-based compensation			15	18
Issuance of preference stock			463	294
Redemption of preference stock			(475)	(125)
Balance, at the end of the period	$ 14,610	$ 14,062	$ 14,610	$ 14,062
Dividends declared per common share (in dollars per share)	$ 0.5425	$ 0.4800	$ 1.6275	$ 1.4400
Accounting for Share-Based Payments
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income				$ 965
Stock-based compensation				(72)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			$ 2,505	2,484
Stock-based compensation				(1)
Non-cash stock-based compensation			15	18
Balance, at the end of the period	$ 2,520	$ 2,501	2,520	2,501
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			(53)	(56)
Other comprehensive income (loss)			5	5
Balance, at the end of the period	(48)	(51)	(48)	(51)
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			9,544	8,940
Net income			1,110	982
Dividends declared on common stock			(530)	(469)
Stock-based compensation			(165)	(30)
Redemption of preference stock			(15)	(2)
Balance, at the end of the period	9,944	9,421	9,944	9,421
Subtotal
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			11,996	11,368
Net income			1,110	982
Other comprehensive income (loss)			5	5
Dividends declared on common stock			(530)	(469)
Stock-based compensation			(165)	(31)
Non-cash stock-based compensation			15	18
Redemption of preference stock			(15)	(2)
Balance, at the end of the period	12,416	11,871	12,416	11,871
Preferred and Preference Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2,191	2,020
Net income			94	92
Dividends to noncontrolling interests			(94)	(92)
Issuance of preference stock			463	294
Redemption of preference stock			(460)	(123)
Balance, at the end of the period	2,194	2,191	2,194	2,191
Southern California Edison
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			14,483	13,672
Net income	497	466	1,215	1,140
Other comprehensive income (loss)	0	1	2	3
Dividends declared on common stock			(573)	(510)
Dividends declared on preferred and preference stock			(94)	(92)
Stock-based compensation			(36)	(43)
Non-cash stock-based compensation			8	8
Issuance of preference stock			463	294
Redemption of preference stock			(475)	(125)
Balance, at the end of the period	14,993	14,347	14,993	14,347
Southern California Edison | Accounting for Share-Based Payments
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income				1,130
Stock-based compensation				(49)
Southern California Edison | Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2,168	2,168
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			657	652
Non-cash stock-based compensation			8	8
Issuance of preference stock			(12)	(6)
Redemption of preference stock			15	2
Balance, at the end of the period	668	656	668	656
Southern California Edison | Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			(20)	(22)
Other comprehensive income (loss)			2	3
Balance, at the end of the period	(18)	(19)	(18)	(19)
Southern California Edison | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			9,433	8,804
Net income			1,215	1,140
Dividends declared on common stock			(573)	(510)
Dividends declared on preferred and preference stock			(94)	(92)
Stock-based compensation			(36)	(43)
Redemption of preference stock			(15)	(2)
Balance, at the end of the period	9,930	9,297	9,930	9,297
Southern California Edison | Preferred and Preference Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, at the beginning of the period			2,245	2,070
Issuance of preference stock			475	300
Redemption of preference stock			(475)	(125)
Balance, at the end of the period	$ 2,245	$ 2,245	$ 2,245	$ 2,245