SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revenues Disaggregated by Type of Customer) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Abstract]
Total operating revenues	$ 20,642	$ 18,469	$ 17,129
Electric
Disaggregation of Revenue [Abstract]
Total operating revenues	15,131	13,858	12,740
Natural gas
Disaggregation of Revenue [Abstract]
Total operating revenues	5,511	4,611	4,389
Pacific Gas & Electric Co (Utility)
Disaggregation of Revenue [Abstract]
Total operating revenues	20,642	18,469	17,129
Pacific Gas & Electric Co (Utility) | Electric
Disaggregation of Revenue [Abstract]
Total operating revenues	14,178	13,185
Regulatory balancing accounts	953	673
Total operating revenues	15,131	13,858	12,740
Pacific Gas & Electric Co (Utility) | Electric | Residential
Disaggregation of Revenue [Abstract]
Total operating revenues	6,089	5,523
Pacific Gas & Electric Co (Utility) | Electric | Commercial
Disaggregation of Revenue [Abstract]
Total operating revenues	5,042	4,722
Pacific Gas & Electric Co (Utility) | Electric | Industrial
Disaggregation of Revenue [Abstract]
Total operating revenues	1,493	1,530
Pacific Gas & Electric Co (Utility) | Electric | Agricultural
Disaggregation of Revenue [Abstract]
Total operating revenues	1,565	1,471
Pacific Gas & Electric Co (Utility) | Electric | Public street and highway lighting
Disaggregation of Revenue [Abstract]
Total operating revenues	73	69
Pacific Gas & Electric Co (Utility) | Electric | Other
Disaggregation of Revenue [Abstract]
Total operating revenues	(84)	(130)
Pacific Gas & Electric Co (Utility) | Natural gas
Disaggregation of Revenue [Abstract]
Total operating revenues	4,958	4,386
Regulatory balancing accounts	553	225
Total operating revenues	5,511	4,611	$ 4,389
Pacific Gas & Electric Co (Utility) | Natural gas | Residential
Disaggregation of Revenue [Abstract]
Total operating revenues	2,759	2,517
Pacific Gas & Electric Co (Utility) | Natural gas | Commercial
Disaggregation of Revenue [Abstract]
Total operating revenues	713	597
Pacific Gas & Electric Co (Utility) | Natural gas | Transportation service only
Disaggregation of Revenue [Abstract]
Total operating revenues	1,346	1,211
Pacific Gas & Electric Co (Utility) | Natural gas | Other
Disaggregation of Revenue [Abstract]
Total operating revenues	$ 140	$ 61