Subsidiary Debt - NV Energy (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Par value	$ 51,702
Subsidiary debt
Debt Instrument [Line Items]
Par value	37,501
Subsidiary debt	37,539	$ 36,659
NV Energy | Subsidiary debt
Debt Instrument [Line Items]
Par value	4,386
Subsidiary debt	4,354	3,675
Debt, net of fair value adjustments	4,354	3,675
NPC
Debt Instrument [Line Items]
Eligible property subject to lien of mortgages	9,800
NPC | Subsidiary debt
Debt Instrument [Line Items]
Par value	3,234
Subsidiary debt	3,195	2,499
Fair value adjustments	10	11
Debt, net of fair value adjustments	$ 3,205	2,510
NPC | Subsidiary debt | 3.700% Series CC, due 2029
Debt Instrument [Line Items]
Stated rate	3.70%
Par value	$ 500
Subsidiary debt	$ 497	497
NPC | Subsidiary debt | 2.400% Series DD, due 2030
Debt Instrument [Line Items]
Stated rate	2.40%
Par value	$ 425
Subsidiary debt	$ 422	422
NPC | Subsidiary debt | 6.650% Series N, due 2036
Debt Instrument [Line Items]
Stated rate	6.65%
Par value	$ 367
Subsidiary debt	$ 360	359
NPC | Subsidiary debt | 6.750% Series R, due 2037
Debt Instrument [Line Items]
Stated rate	6.75%
Par value	$ 349
Subsidiary debt	$ 346	346
NPC | Subsidiary debt | 5.375% Series X, due 2040
Debt Instrument [Line Items]
Stated rate	5.375%
Par value	$ 250
Subsidiary debt	$ 248	248
NPC | Subsidiary debt | 5.450% Series Y, due 2041
Debt Instrument [Line Items]
Stated rate	5.45%
Par value	$ 250
Subsidiary debt	$ 239	239
NPC | Subsidiary debt | 3.125% Series EE, due 2050
Debt Instrument [Line Items]
Stated rate	3.125%
Par value	$ 300
Subsidiary debt	$ 298	297
NPC | Subsidiary debt | 5.900% Series GG, due 2053
Debt Instrument [Line Items]
Stated rate	5.90%
Par value	$ 400
Subsidiary debt	$ 394	0
NPC | Subsidiary debt | 1.875% Pollution Control Bonds Series 2017A, due 2032
Debt Instrument [Line Items]
Stated rate	1.875%
Par value	$ 40
Subsidiary debt	$ 39	39
NPC | Subsidiary debt | 1.650% Pollution Control Bonds Series 2017, due 2036
Debt Instrument [Line Items]
Stated rate	1.65%
Par value	$ 40
Subsidiary debt	$ 39	39
NPC | Subsidiary debt | 1.650% Pollution Control Bonds Series 2017B, due 2039
Debt Instrument [Line Items]
Stated rate	1.65%
Par value	$ 13
Subsidiary debt	$ 13	13
NPC | Subsidiary debt | Variable-rate 4.821% Term Loan, due 2024
Debt Instrument [Line Items]
Stated rate	4.821%
Par value	$ 300
Subsidiary debt	300	0
SPPC
Debt Instrument [Line Items]
Eligible property subject to lien of mortgages	4,900
SPPC | Subsidiary debt
Debt Instrument [Line Items]
Par value	1,152
Subsidiary debt	1,148	1,164
Fair value adjustments	1	1
Debt, net of fair value adjustments	$ 1,149	1,165
SPPC | Subsidiary debt | 3.375% Series T, due 2023
Debt Instrument [Line Items]
Stated rate	3.375%
Par value	$ 250
Subsidiary debt	$ 249	249
SPPC | Subsidiary debt | 2.600% Series U, due 2026
Debt Instrument [Line Items]
Stated rate	2.60%
Par value	$ 400
Subsidiary debt	$ 397	397
SPPC | Subsidiary debt | 6.750% Series P, due 2037
Debt Instrument [Line Items]
Stated rate	6.75%
Par value	$ 252
Subsidiary debt	$ 254	253
SPPC | Subsidiary debt | 4.710% Series W, due 2052
Debt Instrument [Line Items]
Stated rate	4.71%
Par value	$ 250
Subsidiary debt	$ 248	0
SPPC | Subsidiary debt | 1.850% Pollution Control Series 2016B, due 2029
Debt Instrument [Line Items]
Stated rate	1.85%
Par value	$ 0
Subsidiary debt	$ 0	30
SPPC | Subsidiary debt | 3.000% Gas and Water Series 2016B, due 2036
Debt Instrument [Line Items]
Stated rate	3.00%
Par value	$ 0
Subsidiary debt	$ 0	60
SPPC | Subsidiary debt | 0.625% Water Facilities Series 2016C, due 2036
Debt Instrument [Line Items]
Stated rate	0.625%
Par value	$ 0
Subsidiary debt	$ 0	30
SPPC | Subsidiary debt | 2.050% Water Facilities Series 2016D, due 2036
Debt Instrument [Line Items]
Stated rate	2.05%
Par value	$ 0
Subsidiary debt	$ 0	25
SPPC | Subsidiary debt | 2.050% Water Facilities Series 2016E, due 2036
Debt Instrument [Line Items]
Stated rate	2.05%
Par value	$ 0
Subsidiary debt	$ 0	25
SPPC | Subsidiary debt | 2.050% Water Facilities Series 2016F, due 2036
Debt Instrument [Line Items]
Stated rate	2.05%
Par value	$ 0
Subsidiary debt	$ 0	75
SPPC | Subsidiary debt | 1.850% Water Facilities Series 2016G, due 2036
Debt Instrument [Line Items]
Stated rate	1.85%
Par value	$ 0
Subsidiary debt	$ 0	$ 20