Employee Benefit Plans - NPC (Details) - NPC - 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	$ 38	$ 38
Other assets | Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Other non-current assets	10	10
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	$ (6)	$ (6)