SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Sale of Transmission Tower Wireless Licenses) (Details) $ in Millions	Aug. 15, 2021 USD ($)	Feb. 16, 2021 USD ($) 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		$ 946
Proceeds from sale of transmission tower license, final purchase price	947
Proceeds from financing obligation	$ 370
Proceeds from regulatory liabilities, current		471
Proceeds from regulatory liabilities, noncurrent		$ 455
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