SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revenues Disaggregated by Type of Customer) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Abstract]
Total operating revenues	$ 5,798	$ 4,716
Electric
Disaggregation of Revenue [Abstract]
Total operating revenues	4,158	3,395
Natural gas
Disaggregation of Revenue [Abstract]
Total operating revenues	1,640	1,321
Pacific Gas & Electric Co (Utility)
Disaggregation of Revenue [Abstract]
Total operating revenues	5,798	4,716
Pacific Gas & Electric Co (Utility) | Electric
Disaggregation of Revenue [Abstract]
Total operating revenues	3,237	2,909
Regulatory balancing accounts	921	486
Total operating revenues	4,158	3,395
Pacific Gas & Electric Co (Utility) | Electric | Residential
Disaggregation of Revenue [Abstract]
Total operating revenues	1,494	1,464
Pacific Gas & Electric Co (Utility) | Electric | Commercial
Disaggregation of Revenue [Abstract]
Total operating revenues	1,173	1,013
Pacific Gas & Electric Co (Utility) | Electric | Industrial
Disaggregation of Revenue [Abstract]
Total operating revenues	350	327
Pacific Gas & Electric Co (Utility) | Electric | Agricultural
Disaggregation of Revenue [Abstract]
Total operating revenues	216	152
Pacific Gas & Electric Co (Utility) | Electric | Public street and highway lighting
Disaggregation of Revenue [Abstract]
Total operating revenues	18	17
Pacific Gas & Electric Co (Utility) | Electric | Other
Disaggregation of Revenue [Abstract]
Total operating revenues	(14)	(64)
Pacific Gas & Electric Co (Utility) | Natural gas
Disaggregation of Revenue [Abstract]
Total operating revenues	2,027	1,732
Regulatory balancing accounts	(387)	(411)
Total operating revenues	1,640	1,321
Pacific Gas & Electric Co (Utility) | Natural gas | Residential
Disaggregation of Revenue [Abstract]
Total operating revenues	1,464	1,208
Pacific Gas & Electric Co (Utility) | Natural gas | Commercial
Disaggregation of Revenue [Abstract]
Total operating revenues	344	245
Pacific Gas & Electric Co (Utility) | Natural gas | Transportation service only
Disaggregation of Revenue [Abstract]
Total operating revenues	399	326
Pacific Gas & Electric Co (Utility) | Natural gas | Other
Disaggregation of Revenue [Abstract]
Total operating revenues	$ (180)	$ (47)