SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Leases (Details) ft² in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($)	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	$ 142
Financing lease, right of use asset, net	787
Accumulated amortization	108
Leasehold improvements	218
Leasehold incentives	134
Financing lease liabilities	259	$ 0
Financing lease liabilities	$ 554	0
Weighted average remaining lease term, finance lease	1 year 7 months 6 days
Weighted average discount rate, finance lease	6.50%
Lease payments	$ 1,900	$ 2,300
Weighted average remaining lease term. operating lease	8 years 2 months 12 days	19 years 7 months 6 days
Weighted average discount rate, operating lease	6.40%	6.50%
Pacific Gas & Electric Co (Utility)
Lessee, Lease, Description [Line Items]
Financing lease liabilities	$ 259	$ 0
Financing lease liabilities	$ 554	$ 0
Oakland Headquarters Lease | Pacific Gas & Electric Co (Utility)
Lessee, Lease, Description [Line Items]
Rentable square feet | ft²	659					910
Lease, option payment letter of credit						$ 75
Lease, security letter of credit						$ 75
Purchase price					$ 906
Purchase price, deposits					$ 150
Oakland Headquarters Lease | Pacific Gas & Electric Co (Utility) | Forecast
Lessee, Lease, Description [Line Items]
Purchase price, deposits			$ 506	$ 250
Purchase price, deposits credit			$ 172