SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revenues Disaggregated by Type of Customer) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounting Policies [Abstract]
Period for probable revenue recovery			24 months
Pacific Gas & Electric Co (Utility)
Revenue from contracts with customers
Total operating revenues	$ 5,215	$ 4,533	$ 9,931	$ 8,839
Pacific Gas & Electric Co (Utility) | Electric
Revenue from contracts with customers
Total revenue from contracts with customers	3,574	3,058	6,483	5,722
Regulatory balancing accounts	377	377	863	753
Total operating revenues	3,951	3,435	7,346	6,475
Pacific Gas & Electric Co (Utility) | Electric | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	1,352	987	2,815	2,230
Pacific Gas & Electric Co (Utility) | Electric | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	1,183	1,075	2,196	2,082
Pacific Gas & Electric Co (Utility) | Electric | Industrial
Revenue from contracts with customers
Total revenue from contracts with customers	305	342	632	682
Pacific Gas & Electric Co (Utility) | Electric | Agricultural
Revenue from contracts with customers
Total revenue from contracts with customers	431	368	583	491
Pacific Gas & Electric Co (Utility) | Electric | Public street and highway lighting
Revenue from contracts with customers
Total revenue from contracts with customers	18	17	35	34
Pacific Gas & Electric Co (Utility) | Electric | Other
Revenue from contracts with customers
Total revenue from contracts with customers	285	269	222	203
Pacific Gas & Electric Co (Utility) | Natural gas
Revenue from contracts with customers
Total revenue from contracts with customers	766	673	2,498	2,299
Regulatory balancing accounts	498	425	87	65
Total operating revenues	1,264	1,098	2,585	2,364
Pacific Gas & Electric Co (Utility) | Natural gas | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	418	426	1,626	1,492
Pacific Gas & Electric Co (Utility) | Natural gas | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	139	110	384	344
Pacific Gas & Electric Co (Utility) | Natural gas | Transportation service only
Revenue from contracts with customers
Total revenue from contracts with customers	346	296	672	643
Pacific Gas & Electric Co (Utility) | Natural gas | Other
Revenue from contracts with customers
Total revenue from contracts with customers	$ (137)	$ (159)	$ (184)	$ (180)