Subsidiary Debt - NV Energy (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Par value	$ 36,295
Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	27,476
Other long-term debt	27,354	$ 27,214
NV Energy [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	4,569
Other long-term debt	4,582	4,860
NV Energy, Inc. [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Senior Notes, 6.250%, due 2020 [Member]
Debt Instrument [Line Items]
Par value	315
Other long-term debt	$ 363	$ 373
Debt Instrument, Interest Rate, Stated Percentage	6.25%	6.25%
Nevada Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 3,100
Eligible Property Subject To Lien Of Mortgages	$ 8,900
Nevada Power Company [Member] | Mortgage Securities, 5.950%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.95%	5.95%
Nevada Power Company [Member] | Mortgage Securities, 6.500%, Series O due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.50%	6.50%
Nevada Power Company [Member] | Mortgage Securities, 6.500%, Series S due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.50%	6.50%
Nevada Power Company [Member] | Mortgage Securities, 7.125%, Series V due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.125%	7.125%
Nevada Power Company [Member] | Mortgage Securities, 6.650%, Series N due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.65%	6.65%
Nevada Power Company [Member] | Mortgage Securities, 6.750%, Series R due 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.75%	6.75%
Nevada Power Company [Member] | Mortgage Securities, 5.375%, Series X due 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.375%	5.375%
Nevada Power Company [Member] | Mortgage Securities, 5.450%, Series Y due 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.45%	5.45%
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 5.950%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Par value	$ 0
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 6.500%, Series O due 2018 [Member]
Debt Instrument [Line Items]
Par value	324
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 6.500%, Series S due 2018 [Member]
Debt Instrument [Line Items]
Par value	499
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 7.125%, Series V due 2019 [Member]
Debt Instrument [Line Items]
Par value	500
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 6.650%, Series N due 2036 [Member]
Debt Instrument [Line Items]
Par value	367
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 6.750%, Series R due 2037 [Member]
Debt Instrument [Line Items]
Par value	349
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 5.375%, Series X due 2040 [Member]
Debt Instrument [Line Items]
Par value	250
Nevada Power Company [Member] | NV Energy [Member] | Mortgage Securities, 5.450%, Series Y due 2041 [Member]
Debt Instrument [Line Items]
Par value	250
Nevada Power Company [Member] | NV Energy [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Par value	38
Nevada Power Company [Member] | NV Energy [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Par value	38
Nevada Power Company [Member] | NV Energy [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Par value	485
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	3,100
Other long-term debt	3,066	$ 3,285
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 5.950%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 0	$ 210
Debt Instrument, Interest Rate, Stated Percentage	5.95%	5.95%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 6.500%, Series O due 2018 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 324	$ 323
Debt Instrument, Interest Rate, Stated Percentage	6.50%	6.50%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 6.500%, Series S due 2018 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 498	$ 498
Debt Instrument, Interest Rate, Stated Percentage	6.50%	6.50%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 7.125%, Series V due 2019 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 499	$ 499
Debt Instrument, Interest Rate, Stated Percentage	7.125%	7.125%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 6.650%, Series N due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 357	$ 356
Debt Instrument, Interest Rate, Stated Percentage	6.65%	6.65%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 6.750%, Series R due 2037 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 345	$ 345
Debt Instrument, Interest Rate, Stated Percentage	6.75%	6.75%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 5.375%, Series X due 2040 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 247	$ 247
Debt Instrument, Interest Rate, Stated Percentage	5.375%	5.375%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage Securities, 5.450%, Series Y due 2041 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 236	$ 235
Debt Instrument, Interest Rate, Stated Percentage	5.45%	5.45%
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 38	$ 38
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	37	37
Nevada Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 485	$ 497
Nevada Power Company [Member] | Minimum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.89%	0.672%
Nevada Power Company [Member] | Minimum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.89%	0.672%
Nevada Power Company [Member] | Minimum [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	2.75%	2.75%
Nevada Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.89%	0.672%
Nevada Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.89%	0.672%
Nevada Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	2.75%	2.75%
Nevada Power Company [Member] | Maximum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.928%	1.055%
Nevada Power Company [Member] | Maximum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.928%	1.055%
Nevada Power Company [Member] | Maximum [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	11.60%	11.60%
Nevada Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.928%	1.055%
Nevada Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.928%	1.055%
Nevada Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	11.60%	11.60%
Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 1,154
Eligible Property Subject To Lien Of Mortgages	$ 3,800
Sierra Pacific Power Company [Member] | Mortgage securities, 6.000%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%	6.00%
Sierra Pacific Power Company [Member] | Mortgage securities, 3.375%, Series T due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.375%	3.375%
Sierra Pacific Power Company [Member] | Mortgage securities, 2.600%, Series U due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.60%
Sierra Pacific Power Company [Member] | Mortgage securities, 6.750%, Series P due 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.75%	6.75%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Mortgage securities, 6.000%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Par value	$ 0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Mortgage securities, 3.375%, Series T due 2023 [Member]
Debt Instrument [Line Items]
Par value	250
Sierra Pacific Power Company [Member] | NV Energy [Member] | Mortgage securities, 2.600%, Series U due 2026 [Member]
Debt Instrument [Line Items]
Par value	400
Sierra Pacific Power Company [Member] | NV Energy [Member] | Mortgage securities, 6.750%, Series P due 2037 [Member]
Debt Instrument [Line Items]
Par value	252
Sierra Pacific Power Company [Member] | NV Energy [Member] | Pollution Control Refunding Revenue Bonds, 1.250%, Series 2016A, due 2029 [Member]
Debt Instrument [Line Items]
Par value	20
Sierra Pacific Power Company [Member] | NV Energy [Member] | Gas facilities refunding revenue bonds, 1.500%, series 2016A, due 2031 [Member]
Debt Instrument [Line Items]
Par value	58
Sierra Pacific Power Company [Member] | NV Energy [Member] | Gas and water facilities refunding revenue bonds, 3.000% series 2016B, due 2036 [Member]
Debt Instrument [Line Items]
Par value	60
Sierra Pacific Power Company [Member] | NV Energy [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006A due 2031 [Member]
Debt Instrument [Line Items]
Par value	0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006B due 2036 [Member]
Debt Instrument [Line Items]
Par value	0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006C due 2036 [Member]
Debt Instrument [Line Items]
Par value	0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Water facilities refunding revenue bonds, series 2016C, due 2036 [Member]
Debt Instrument [Line Items]
Par value	30
Sierra Pacific Power Company [Member] | NV Energy [Member] | Water facilities refunding revenue bonds, series 2016D, due 2036 [Member]
Debt Instrument [Line Items]
Par value	25
Sierra Pacific Power Company [Member] | NV Energy [Member] | Water facilities refunding revenue bonds, series 2016E, due 2036 [Member]
Debt Instrument [Line Items]
Par value	25
Sierra Pacific Power Company [Member] | NV Energy [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member]
Debt Instrument [Line Items]
Par value	34
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	1,154
Other long-term debt	1,153	$ 1,202
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage securities, 6.000%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 0	$ 450
Debt Instrument, Interest Rate, Stated Percentage	6.00%	6.00%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage securities, 3.375%, Series T due 2023 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 248	$ 248
Debt Instrument, Interest Rate, Stated Percentage	3.375%	3.375%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage securities, 2.600%, Series U due 2026 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 395	$ 0
Debt Instrument, Interest Rate, Stated Percentage		2.60%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Mortgage securities, 6.750%, Series P due 2037 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 255	$ 255
Debt Instrument, Interest Rate, Stated Percentage	6.75%	6.75%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Refunding Revenue Bonds, 1.250%, Series 2016A, due 2029 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 20	$ 0
Debt Instrument, Interest Rate, Stated Percentage	1.25%	1.25%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Gas facilities refunding revenue bonds, 1.500%, series 2016A, due 2031 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 58	$ 0
Debt Instrument, Interest Rate, Stated Percentage	1.50%	1.50%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Gas and water facilities refunding revenue bonds, 3.000% series 2016B, due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 64	$ 0
Debt Instrument, Interest Rate, Stated Percentage	3.00%	3.00%
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006A due 2031 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 0	$ 58
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006B due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	0	74
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006C due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	0	80
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016C, due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	29	0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016D, due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	25	0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016E, due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt	25	0
Sierra Pacific Power Company [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 34	$ 37
Sierra Pacific Power Company [Member] | Minimum [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	2.70%	2.70%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006A due 2031 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.788%	0.733%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006B due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.788%	0.733%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006C due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.788%	0.733%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016C, due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.788%	0.733%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016D, due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.788%	0.733%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016E, due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.788%	0.733%
Sierra Pacific Power Company [Member] | Minimum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	2.70%	2.70%
Sierra Pacific Power Company [Member] | Maximum [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	10.13%	8.548%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006A due 2031 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.80%	1.054%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006B due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.80%	1.054%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Pollution Control Revenue Bonds, 0.464% to 0.466%, Series 2006C due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.80%	1.054%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016C, due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.80%	1.054%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016D, due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.80%	1.054%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Water facilities refunding revenue bonds, series 2016E, due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.80%	1.054%
Sierra Pacific Power Company [Member] | Maximum [Member] | NV Energy [Member] | Subsidiary Debt [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	10.13%	8.548%