Subsidiary Debt Subsidiary Debt - SPPC - Capital and Financial Lease Obligations (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
Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	1,154
Total Long-term Debt and Capital and Financial Lease Obligations	1,153	1,202
Long-term Debt and Capital and Financial Lease Obligations, Current	1	453
Long-term Debt and Capital and Financial Lease Obligations	1,152	749
Long-term Debt and Capital and Financial Lease Obligations, Including Current Maturities	1,153	1,202
NV Energy [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	4,569
Other long-term debt	4,582	4,860
NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value	1,154
Other long-term debt	$ 1,153	$ 1,202
Mortgage securities, 6.000%, Series M due 2016 [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%	6.00%
Mortgage securities, 6.000%, Series M due 2016 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 0
Mortgage securities, 6.000%, Series M due 2016 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 0	$ 450
Debt Instrument, Interest Rate, Stated Percentage	6.00%	6.00%
Mortgage securities, 3.375%, Series T due 2023 [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.375%	3.375%
Mortgage securities, 3.375%, Series T due 2023 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 250
Mortgage securities, 3.375%, Series T due 2023 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 248	$ 248
Debt Instrument, Interest Rate, Stated Percentage	3.375%	3.375%
Mortgage securities, 2.600%, Series U due 2026 [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.60%
Mortgage securities, 2.600%, Series U due 2026 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 400
Mortgage securities, 2.600%, Series U due 2026 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 395	$ 0
Debt Instrument, Interest Rate, Stated Percentage		2.60%
Mortgage securities, 6.750%, Series P due 2037 [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.75%	6.75%
Mortgage securities, 6.750%, Series P due 2037 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 252
Mortgage securities, 6.750%, Series P due 2037 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 255	$ 255
Debt Instrument, Interest Rate, Stated Percentage	6.75%	6.75%
Pollution Control Refunding Revenue Bonds, 1.250%, Series 2016A, due 2029 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 20
Pollution Control Refunding Revenue Bonds, 1.250%, Series 2016A, due 2029 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 20	$ 0
Debt Instrument, Interest Rate, Stated Percentage	1.25%	1.25%
Gas facilities refunding revenue bonds, 1.500%, series 2016A, due 2031 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 58
Gas facilities refunding revenue bonds, 1.500%, series 2016A, due 2031 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 58	$ 0
Debt Instrument, Interest Rate, Stated Percentage	1.50%	1.50%
Gas and water facilities refunding revenue bonds, 3.000% series 2016B, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 60
Gas and water facilities refunding revenue bonds, 3.000% series 2016B, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 64	$ 0
Debt Instrument, Interest Rate, Stated Percentage	3.00%	3.00%
Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2031 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	$ 0
Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2031 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	0	$ 58
Pollution Control Revenue Bonds, Variable-Rate, Series 2006B due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	0
Pollution Control Revenue Bonds, Variable-Rate, Series 2006B due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	0	74
Pollution Control Revenue Bonds, Variable-Rate, Series 2006C due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	0
Pollution Control Revenue Bonds, Variable-Rate, Series 2006C due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	0	80
Water facilities refunding revenue bonds, series 2016C, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	30
Water facilities refunding revenue bonds, series 2016C, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	29	0
Water facilities refunding revenue bonds, series 2016D, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	25
Water facilities refunding revenue bonds, series 2016D, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	25	0
Water facilities refunding revenue bonds, series 2016E, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	25
Water facilities refunding revenue bonds, series 2016E, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	25	0
Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Par value	34
Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Other long-term debt	$ 34	$ 37
Minimum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2031 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.788%	0.733%
Minimum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006B due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.788%	0.733%
Minimum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006C due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.788%	0.733%
Minimum [Member] | Water facilities refunding revenue bonds, series 2016C, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.788%	0.733%
Minimum [Member] | Water facilities refunding revenue bonds, series 2016D, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.788%	0.733%
Minimum [Member] | Water facilities refunding revenue bonds, series 2016E, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.788%	0.733%
Minimum [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Variable interest rate	2.70%	2.70%
Minimum [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	2.70%	2.70%
Maximum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2031 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.80%	1.054%
Maximum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006B due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.80%	1.054%
Maximum [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006C due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.80%	1.054%
Maximum [Member] | Water facilities refunding revenue bonds, series 2016C, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.80%	1.054%
Maximum [Member] | Water facilities refunding revenue bonds, series 2016D, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.80%	1.054%
Maximum [Member] | Water facilities refunding revenue bonds, series 2016E, due 2036 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	0.80%	1.054%
Maximum [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Variable interest rate	10.13%	8.548%
Maximum [Member] | Capital and financial lease obligations, 2.700% to 8.548%, due through 2054 [Member] | NV Energy [Member] | Sierra Pacific Power Company [Member] | Subsidiary Debt [Member]
Debt Instrument [Line Items]
Variable interest rate	10.13%	8.548%
Equipment [Member] | Sierra Pacific Power Company [Member]
Debt Instrument [Line Items]
Capital Leased Assets, Gross	$ 3	$ 3