SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) numberOfFatality	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 30, 2020 USD ($)	Oct. 05, 2020 USD ($)	Jul. 12, 2019 USD ($)
Public Utility, Property, Plant and Equipment [Line Items]
Period for probable revenue recovery	24 months
Expected wildfire fund allocation metric, initial contribution						$ 4,800,000,000
Expected wildfire fund allocation metric, annual contributions						$ 193,000,000
Expected wildfire fund allocation metric, annual contributions, second				$ 193,000,000
Litigation liability, current	$ 193,000,000
Wildfire fund asset	464,000,000	$ 0
Litigation contribution, net	5,800,000,000
Amortization and accretion	$ 413,000,000	0	$ 0
Monte carlo simulation, historical data, period	12 years
Amortization period	6 years
Percentage assumption change	10.00%
Greater effectiveness, amortization period	17 years
Less effectiveness, amortization period	12 years
Operating lease, payments	$ 2,500,000,000	$ 2,400,000,000
Weighted average remaining lease term	5 years 8 months 12 days	5 years 10 months 24 days
Weighted average discount rate	6.20%	6.20%
Allowance for credit loss	$ 150,000,000
Regulatory assets, probable recovery	76,000,000
Regulatory assets, deferred amount	$ 10,000,000
Five Year Historical Period
Public Utility, Property, Plant and Equipment [Line Items]
Historical data period	5 years
Average annual statewide claims or settlements	$ 6,500,000,000
Twelve Year Historical Period
Public Utility, Property, Plant and Equipment [Line Items]
Historical data period	12 years
Average annual statewide claims or settlements	$ 2,900,000,000
Wildfire Fund Asset
Public Utility, Property, Plant and Equipment [Line Items]
Finite-lived intangible asset, useful life	15 years
Noncurrent liabilities – other
Public Utility, Property, Plant and Equipment [Line Items]
Wildfire fund, noncurrent	$ 1,300,000,000
Pacific Gas & Electric Co (Utility)
Public Utility, Property, Plant and Equipment [Line Items]
Composite depreciation rate	3.76%	3.80%	3.82%
AFUDC debt recorded	$ 35,000,000	$ 55,000,000	$ 53,000,000
AFUDC equity recorded	140,000,000	79,000,000	129,000,000
Nuclear decommissioning obligation accrued	5,100,000,000	4,900,000,000
Estimated cost recovery on spent nuclear fuel storage proceeding every year	10,600,000,000	10,600,000,000
Wildfire fund asset	464,000,000	0
Amortization and accretion	413,000,000	$ 0	$ 0
Pacific Gas & Electric Co (Utility) | Receivables Securitization Program
Public Utility, Property, Plant and Equipment [Line Items]
Aggregate maximum amount of loans made by lenders	1,000,000,000.0				$ 1,000,000,000.0
Long-term debt, gross	$ 1,000,000,000.0
Pacific Gas & Electric Co (Utility) | Diablo Canyon
Public Utility, Property, Plant and Equipment [Line Items]
Number of generation facilities | numberOfFatality	2
Pacific Gas & Electric Co (Utility) | Humboldt Bay
Public Utility, Property, Plant and Equipment [Line Items]
Number of generation facilities | numberOfFatality	1
PG&E AR Facility, LLC (SPV) | Receivables Securitization Program
Public Utility, Property, Plant and Equipment [Line Items]
Accounts receivable, net	$ 2,600,000,000