SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revenues Disaggregated by Type of Customer) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounting Policies [Abstract]
Period for probable revenue recovery	24 months
Pacific Gas & Electric Co
Revenue from contracts with customers
Total operating revenues	$ 4,306	$ 4,011
Pacific Gas & Electric Co | Electric
Revenue from contracts with customers
Total revenue from contracts with customers	2,664	2,328
Regulatory balancing accounts	376	464
Total operating revenues	3,040	2,792
Pacific Gas & Electric Co | Electric | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	1,242	1,288
Pacific Gas & Electric Co | Electric | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	1,007	953
Pacific Gas & Electric Co | Electric | Industrial
Revenue from contracts with customers
Total revenue from contracts with customers	341	293
Pacific Gas & Electric Co | Electric | Agricultural
Revenue from contracts with customers
Total revenue from contracts with customers	123	86
Pacific Gas & Electric Co | Electric | Public street and highway lighting
Revenue from contracts with customers
Total revenue from contracts with customers	17	17
Pacific Gas & Electric Co | Electric | Other
Revenue from contracts with customers
Total revenue from contracts with customers	(66)	(309)
Pacific Gas & Electric Co | Natural gas
Revenue from contracts with customers
Total revenue from contracts with customers	1,626	1,718
Regulatory balancing accounts	(360)	(499)
Total operating revenues	1,266	1,219
Pacific Gas & Electric Co | Natural gas | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	1,066	1,171
Pacific Gas & Electric Co | Natural gas | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	234	240
Pacific Gas & Electric Co | Natural gas | Transportation service only
Revenue from contracts with customers
Total revenue from contracts with customers	348	382
Pacific Gas & Electric Co | Natural gas | Other
Revenue from contracts with customers
Total revenue from contracts with customers	$ (22)	$ (75)