REGULATORY ASSETS, LIABILITIES, AND BALANCING ACCOUNTS (Long-Term Regulatory Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	$ 11,999	$ 10,424
Proceeds received from sale of transmission tower wireless licenses, refunded to customers	446
Federal Energy Regulatory Commission
Regulatory Liabilities [Line Items]
Proceeds received from sale of transmission tower wireless licenses, refunded to customers	311
California Public Utilities Commission
Regulatory Liabilities [Line Items]
Proceeds received from sale of transmission tower wireless licenses, refunded to customers	135
Cost of removal obligations
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	7,306	6,905
Recoveries in excess of AROs
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	388	458
Public purpose programs
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	946	948
Employee benefit plans
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	1,229	995
Transmission tower wireless licenses
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	446	0
SFGO sale
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	343	0
Other
Regulatory Liabilities [Line Items]
Total long-term regulatory liabilities	$ 1,341	$ 1,118