DERIVATIVES (Outstanding Derivative Balances) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivatives And Hedging Activities [Line Items]
Derivative asset, netting	$ (88)	$ (6)
Derivative liability, netting	10	25
Commodity Contract | Pacific Gas & Electric Co
Derivatives And Hedging Activities [Line Items]
Gross Derivative Assets	90	20
Derivative asset, netting	0	0
Cash Collateral	98	31
Total Derivative Balance, Assets	188	51
Commodity Contract | Pacific Gas & Electric Co | Current assets – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Assets	44	30
Derivative asset, netting	(1)	(3)
Cash Collateral	89	10
Total Derivative Balance, Assets	132	37
Commodity Contract | Pacific Gas & Electric Co | Other noncurrent assets – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Assets	165	103
Derivative asset, netting	0	(1)
Cash Collateral	0	0
Total Derivative Balance, Assets	165	102
Commodity Contract | Pacific Gas & Electric Co | Current liabilities – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Liabilities	(29)	(47)
Derivative liability, netting	1	3
Cash Collateral	7	13
Total Derivative Balance, Liabilities	(21)	(31)
Commodity Contract | Pacific Gas & Electric Co | Noncurrent liabilities – other
Derivatives And Hedging Activities [Line Items]
Gross Derivative Liabilities	(90)	(66)
Derivative liability, netting	0	1
Cash Collateral	2	8
Total Derivative Balance, Liabilities	$ (88)	$ (57)