Subsidiary Debt Subsidiary Debt - NPC - Capital and Financial Lease Obligations (Details) - USD ($) $ in Millions	Jan. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Par value		$ 36,295
Nevada Power Company [Member]
Debt Instrument [Line Items]
Par value		3,100
Total Long-term Debt and Capital and Financial Lease Obligations		3,066	$ 3,285
Long-term Debt and Capital and Financial Lease Obligations, Current		17	225
Long-term Debt and Capital and Financial Lease Obligations		$ 3,049	$ 3,060
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%
Minimum [Member] | Nevada Power Company [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%
Minimum [Member] | Nevada Power Company [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%
Minimum [Member] | Nevada Power Company [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%
Maximum [Member] | Nevada Power Company [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%
Maximum [Member] | Nevada Power Company [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%
Maximum [Member] | Nevada Power Company [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%
Subsidiary Debt [Member]
Debt Instrument [Line Items]
Par value		$ 27,476
Other long-term debt		27,354	$ 27,214
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 5.950%, Series M due 2016 [Member]
Debt Instrument [Line Items]
Par value		0
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 6.500%, Series O due 2018 [Member]
Debt Instrument [Line Items]
Par value		324
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 6.500%, Series S due 2018 [Member]
Debt Instrument [Line Items]
Par value		499
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 7.125%, Series V due 2019 [Member]
Debt Instrument [Line Items]
Par value		500
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 6.650%, Series N due 2036 [Member]
Debt Instrument [Line Items]
Par value		367
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 6.750%, Series R due 2037 [Member]
Debt Instrument [Line Items]
Par value		349
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 5.375%, Series X due 2040 [Member]
Debt Instrument [Line Items]
Par value		250
NV Energy [Member] | Nevada Power Company [Member] | Mortgage Securities, 5.450%, Series Y due 2041 [Member]
Debt Instrument [Line Items]
Par value		250
NV Energy [Member] | Nevada Power Company [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Par value		38
NV Energy [Member] | Nevada Power Company [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Par value		38
NV Energy [Member] | Nevada Power Company [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Par value		485
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] | Subsidiary Debt [Member] | Nevada Power Company [Member]
Debt Instrument [Line Items]
Par value		3,100
Other long-term debt		3,066	3,285
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Other long-term debt		$ 38	$ 38
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Other long-term debt		37	37
NV Energy [Member] | Subsidiary Debt [Member] | Nevada Power Company [Member] | Capital lease obligations, 2.75% to 11.60%, due through 2054 [Member]
Debt Instrument [Line Items]
Other long-term debt		$ 485	$ 497
NV Energy [Member] | Subsidiary Debt [Member] | Minimum [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Minimum [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Minimum [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Maximum [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Maximum [Member] | Nevada Power Company [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%
NV Energy [Member] | Subsidiary Debt [Member] | Maximum [Member] | Nevada Power Company [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%
Equipment [Member] | Nevada Power Company [Member]
Debt Instrument [Line Items]
Capital Leased Assets, Gross			$ 1
Subsequent Event [Member] | NV Energy [Member] | Nevada Power Company [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006A due 2032 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount	$ 38
Subsequent Event [Member] | NV Energy [Member] | Nevada Power Company [Member] | Pollution Control Revenue Bonds, Variable-Rate, Series 2006 due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount	$ 38