REGULATORY ASSETS, LIABILITIES, AND BALANCING ACCOUNTS (Long-Term Regulatory Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Total long-term regulatory assets	$ 9,167	$ 9,207
Utility retained generation asset costs	1,200
Pension benefits
Regulatory Assets [Line Items]
Total long-term regulatory assets	645	708
Environmental compliance costs
Regulatory Assets [Line Items]
Total long-term regulatory assets	1,007	1,089
Utility retained generation
Regulatory Assets [Line Items]
Total long-term regulatory assets	121	133
Price risk management
Regulatory Assets [Line Items]
Total long-term regulatory assets	213	216
Catastrophic event memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	983	1,119
Catastrophic event memorandum account | COVID-19
Regulatory Assets [Line Items]
Total long-term regulatory assets	51	49
Wildfire expense memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	350	347
Fire hazard prevention memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	75	75
Fire risk mitigation memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	50	44
Wildfire mitigation plan memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	461	424
Deferred income taxes
Regulatory Assets [Line Items]
Total long-term regulatory assets	2,036	1,849
Insurance premium costs
Regulatory Assets [Line Items]
Total long-term regulatory assets	186	207
Wildfire mitigation balancing account
Regulatory Assets [Line Items]
Total long-term regulatory assets	$ 273	273
Wildfire mitigation balancing account | Minimum
Regulatory Assets [Line Items]
Cost percentage threshold requiring approval	115.00%
Vegetation management balancing account
Regulatory Assets [Line Items]
Total long-term regulatory assets	$ 1,412	1,411
Vegetation management balancing account | Minimum
Regulatory Assets [Line Items]
Cost percentage threshold requiring approval	120.00%
COVID-19 Pandemic protection memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	$ 48	49
COVID-19 pandemic protection memorandum account, undercollection bad debt
Regulatory Assets [Line Items]
Total long-term regulatory assets	28	30
COVID-19 pandemic protection memorandum account, program and accounts receivable financing costs
Regulatory Assets [Line Items]
Total long-term regulatory assets	20	19
Microgrid memorandum account
Regulatory Assets [Line Items]
Total long-term regulatory assets	164	163
Financing costs
Regulatory Assets [Line Items]
Total long-term regulatory assets	172	175
Other
Regulatory Assets [Line Items]
Total long-term regulatory assets	$ 971	$ 925