SAN ONOFRE NUCLEAR GENERATING STATION - NUCLEAR DECOMMISSIONING TRUSTS (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Cost	$ 731		$ 735
Gross unrealized gains	240		282
Gross unrealized losses	(25)		(5)
Estimated fair value	946		1,012
Proceeds from sales	242	$ 288
Gross realized gains	11	21
Gross realized losses	(4)	$ (2)
Total debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	624		620
Gross unrealized gains	6		20
Gross unrealized losses	(21)		(3)
Estimated fair value	609		637
U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Cost	51		56
Gross unrealized gains	1		0
Gross unrealized losses	(1)		0
Estimated fair value	51		56
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Cost	309		309
Gross unrealized gains	3		13
Gross unrealized losses	(8)		(1)
Estimated fair value	304		321
Other securities
Debt Securities, Available-for-sale [Line Items]
Cost	264		255
Gross unrealized gains	2		7
Gross unrealized losses	(12)		(2)
Estimated fair value	254		260
Equity securities
Debt Securities, Available-for-sale [Line Items]
Cost	99		104
Gross unrealized gains	234		262
Gross unrealized losses	(4)		(2)
Estimated fair value	329		364
Short-term investments, primarily cash equivalents
Debt Securities, Available-for-sale [Line Items]
Cost	3		3
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Estimated fair value	3		3
Receivables (payables), net
Debt Securities, Available-for-sale [Line Items]
Cost	5		8
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Estimated fair value	$ 5		$ 8