SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revenues Disaggregated by Type of Customer) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounting Policies [Abstract]
Period for probable revenue recovery			24 months
Pacific Gas & Electric Co
Revenue from contracts with customers
Total operating revenues	$ 4,882	$ 4,432	$ 13,721	$ 12,386
Pacific Gas & Electric Co | Electric
Revenue from contracts with customers
Total revenue from contracts with customers	4,296	3,935	10,018	8,995
Regulatory balancing accounts	(486)	(381)	267	297
Total operating revenues	3,810	3,554	10,285	9,292
Pacific Gas & Electric Co | Electric | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	1,862	1,557	4,092	3,839
Pacific Gas & Electric Co | Electric | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	1,455	1,481	3,537	3,568
Pacific Gas & Electric Co | Electric | Industrial
Revenue from contracts with customers
Total revenue from contracts with customers	453	466	1,135	1,085
Pacific Gas & Electric Co | Electric | Agricultural
Revenue from contracts with customers
Total revenue from contracts with customers	657	496	1,149	844
Pacific Gas & Electric Co | Electric | Public street and highway lighting
Revenue from contracts with customers
Total revenue from contracts with customers	17	17	51	50
Pacific Gas & Electric Co | Electric | Other
Revenue from contracts with customers
Total revenue from contracts with customers	(148)	(82)	54	(391)
Pacific Gas & Electric Co | Natural gas
Revenue from contracts with customers
Total revenue from contracts with customers	679	507	2,978	2,872
Regulatory balancing accounts	393	371	458	222
Total operating revenues	1,072	878	3,436	3,094
Pacific Gas & Electric Co | Natural gas | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	303	249	1,795	1,764
Pacific Gas & Electric Co | Natural gas | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	90	92	434	461
Pacific Gas & Electric Co | Natural gas | Transportation service only
Revenue from contracts with customers
Total revenue from contracts with customers	259	264	902	950
Pacific Gas & Electric Co | Natural gas | Other
Revenue from contracts with customers
Total revenue from contracts with customers	$ 27	$ (98)	$ (153)	$ (303)