Related Party Transactions - NPC (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Other current liabilities	$ 2,109,000,000	$ 1,551,000,000
Revenues	25,920,000,000	25,602,000,000	$ 26,337,000,000
Accounts payable	2,928,000,000	3,175,000,000
NPC
Related Party Transaction [Line Items]
Other current liabilities	50,000,000	48,000,000
Revenues	2,873,000,000	3,088,000,000	2,630,000,000
Trade receivables, net	314,000,000	374,000,000
Accounts payable	343,000,000	466,000,000
Income tax receivable (payable), related parties current	(82,000,000)	31,000,000
Related party, cash received (paid) income taxes	(177,000,000)	52,000,000	29,000,000
NPC | SPPC
Related Party Transaction [Line Items]
Related party amounts of transaction	19,000,000	19,000,000	16,000,000
Expense reimbursement	31,000,000	28,000,000	25,000,000
NPC | NV Energy
Related Party Transaction [Line Items]
Related party amounts of transaction	8,000,000	9,000,000	9,000,000
Expense reimbursement	8,000,000	4,000,000	3,000,000
NPC | Intercompany administrative services agreement
Related Party Transaction [Line Items]
Related party amounts of transaction	82,000,000	55,000,000	46,000,000
NPC | Natural gas transportation and other services
Related Party Transaction [Line Items]
Related party amounts of transaction	51,000,000	50,000,000	49,000,000
NPC | Electricity services | SPPC
Related Party Transaction [Line Items]
Purchases from related party	29,000,000	70,000,000	86,000,000
NPC | Related party
Related Party Transaction [Line Items]
Other current liabilities	4,000,000	4,000,000
NPC | Related party | PAC
Related Party Transaction [Line Items]
Revenues	2,000,000	1,000,000	4,000,000
Trade receivables, net	0	0
NPC | Related party | SPPC
Related Party Transaction [Line Items]
Trade receivables, net	0	0
Accounts payable	65,000,000	20,000,000
NPC | Related party | NV Energy
Related Party Transaction [Line Items]
Other current liabilities	51,000,000	82,000,000
Trade receivables, net	0	0
NPC | Related party | Electricity services | SPPC
Related Party Transaction [Line Items]
Revenues	188,000,000	230,000,000	$ 362,000,000
Trade receivables, net	7,000,000	10,000,000
Accounts payable	$ 1,000,000	$ 1,000,000