SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Revenues Disaggregated by Type of Customer) (Details) - Pacific Gas & Electric Co $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Revenue from contracts with customers
Total operating revenues	$ 16,760
Electric
Revenue from contracts with customers
Total revenue from contracts with customers	12,077
Regulatory balancing accounts	636
Total operating revenues	12,713
Electric | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	5,051
Electric | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	4,908
Electric | Industrial
Revenue from contracts with customers
Total revenue from contracts with customers	1,532
Electric | Agricultural
Revenue from contracts with customers
Total revenue from contracts with customers	1,234
Electric | Public street and highway lighting
Revenue from contracts with customers
Total revenue from contracts with customers	72
Electric | Other
Revenue from contracts with customers
Total revenue from contracts with customers	(720)
Natural gas
Revenue from contracts with customers
Total revenue from contracts with customers	3,805
Regulatory balancing accounts	242
Total operating revenues	4,047
Natural gas | Residential
Revenue from contracts with customers
Total revenue from contracts with customers	2,042
Natural gas | Commercial
Revenue from contracts with customers
Total revenue from contracts with customers	537
Natural gas | Transportation service only
Revenue from contracts with customers
Total revenue from contracts with customers	1,151
Natural gas | Other
Revenue from contracts with customers
Total revenue from contracts with customers	$ 75