SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Leases (Details) ft² in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($) ft²	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2025 USD ($)	Jul. 11, 2024 USD ($)	Jul. 11, 2023 USD ($)	Oct. 23, 2020 USD ($) ft²
Lessee, Lease, Description [Line Items]
Cash payments for financing lease		$ 315	$ 142
Financing lease, right of use asset, net		807	787
Accumulated amortization		282	108
Leasehold improvements		136	218
Leasehold incentives		51	134
Financing lease liabilities		577	259
Financing lease liabilities		$ 4	$ 554
Weighted average remaining lease term, finance lease		6 months	1 year 7 months 6 days
Weighted average discount rate, finance lease		6.20%	6.50%
Lease payments		$ 1,600	$ 1,900	$ 2,300
Weighted average remaining lease term. operating lease		7 years 6 months	8 years 2 months 12 days
Weighted average discount rate, operating lease		6.50%	6.40%
Pacific Gas & Electric Co (Utility)
Lessee, Lease, Description [Line Items]
Financing lease liabilities		$ 577	$ 259
Financing lease liabilities		$ 4	$ 554
Pacific Gas & Electric Co (Utility) | Forecast
Lessee, Lease, Description [Line Items]
Cash payments for financing lease	$ 591
Oakland Headquarters Lease | Pacific Gas & Electric Co (Utility)
Lessee, Lease, Description [Line Items]
Rentable square feet | ft²		715						910
Lease, option payment letter of credit								$ 75
Lease, security letter of credit								$ 75
Purchase price							$ 906
Purchase price, deposits						$ 250	$ 150
Oakland Headquarters Lease | Pacific Gas & Electric Co (Utility) | Forecast
Lessee, Lease, Description [Line Items]
Purchase price, deposits					$ 506
Purchase price, deposits credit					$ 172
All But Vehicle Lease Agreements
Lessee, Lease, Description [Line Items]
Financing lease liabilities		$ 575