Employee Benefit Plans - SPPC (Details) - SPPC - U.S. - NV Energy, Inc. - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other assets | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Other non-current assets	$ 54	$ 53
Other assets | Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Other non-current assets	0	1
Other current liabilities | Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	(1)	(1)
Other Noncurrent Liabilities | Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Other long-term liabilities	$ (5)	$ (5)