Employee Benefit Plans - NPC (Details) - NPC - U.S. - NV Energy - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Other Assets | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Other non-current assets	$ 26	$ 27
Other Assets | Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Other non-current assets	7	7
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)