SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Sale of Transmission Tower Wireless Licenses) (Details) $ in Millions	Feb. 16, 2021 USD ($) transmissionTower
Public Utility, Property, Plant and Equipment [Line Items]
Proceeds from contract liability	$ 106
Pacific Gas & Electric Co (Utility) | SBA Communications Corporation | Wireless Licenses
Public Utility, Property, Plant and Equipment [Line Items]
Duration of contract	100 years
Other tower, duration of contract	15 years
Proceeds from sale of transmission tower license	$ 973
Proceeds from sale of transmission tower license, closing	946
Proceeds from financing obligation	365
Proceeds from regulatory liabilities, current	475
Proceeds from regulatory liabilities, noncurrent	$ 471
Pacific Gas & Electric Co (Utility) | SBA Communications Corporation | Minimum | Effective Date Towers | Wireless Licenses
Public Utility, Property, Plant and Equipment [Line Items]
Number of electric transmission towers | transmissionTower	700
Number of other electric transmission towers | transmissionTower	28,000