Related Party Transactions - NPC (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 30, 2022
Related Party Transaction [Line Items]
Other current liabilities	$ 1,551,000,000	$ 1,677,000,000
Revenues	25,602,000,000	26,337,000,000	$ 25,150,000,000
Accounts payable	3,175,000,000	2,679,000,000
NPC
Related Party Transaction [Line Items]
Other current liabilities	48,000,000	49,000,000
Revenues	3,088,000,000	2,630,000,000	2,139,000,000
Trade receivables, net	374,000,000	388,000,000
Accounts payable	466,000,000	422,000,000
Income tax receivable (payable), related parties current	(31,000,000)	12,000,000
Related party, cash received (paid) income taxes	52,000,000	29,000,000	(63,000,000)
NPC | SPPC
Related Party Transaction [Line Items]
Related party amounts of transaction	19,000,000	16,000,000	15,000,000
Expense reimbursement	28,000,000	25,000,000	25,000,000
NPC | NV Energy
Related Party Transaction [Line Items]
Related party amounts of transaction	9,000,000	9,000,000	9,000,000
Expense reimbursement	4,000,000	3,000,000	1,000,000
NPC | Intercompany administrative services agreement
Related Party Transaction [Line Items]
Related party amounts of transaction	55,000,000	46,000,000	30,000,000
NPC | Natural gas transportation and other services
Related Party Transaction [Line Items]
Related party amounts of transaction	50,000,000	49,000,000	52,000,000
NPC | Electricity services | SPPC
Related Party Transaction [Line Items]
Purchases from related party	70,000,000	86,000,000	43,000,000
NPC | Related party
Related Party Transaction [Line Items]
Other current liabilities	4,000,000	3,000,000
NPC | Related party | PAC
Related Party Transaction [Line Items]
Revenues	1,000,000	4,000,000	3,000,000
Trade receivables, net	0	0
NPC | Related party | SPPC
Related Party Transaction [Line Items]
Trade receivables, net	0	33,000,000
Accounts payable	20,000,000	0
NPC | Related party | NV Energy
Related Party Transaction [Line Items]
Other current liabilities	82,000,000	51,000,000
Trade receivables, net	0	0
Notes receivable from affiliates	0	100,000,000		$ 100,000,000
NPC | Related party | Electricity services | SPPC
Related Party Transaction [Line Items]
Revenues	230,000,000	362,000,000	$ 179,000,000
Trade receivables, net	10,000,000	41,000,000
Accounts payable	$ 1,000,000	$ 5,000,000