Leases Leases - SPPC - Maturity Table (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months		$ 147
Lessee, Operating Lease, Liability, Payments, Due Year Two		126
Lessee, Operating Lease, Liability, Payments, Due Year Three		102
Lessee, Operating Lease, Liability, Payments, Due Year Four		73
Lessee, Operating Lease, Liability, Payments, Due Year Five		50
Lessee, Operating Lease, Liability, Payments, Due after Year Five		202
Lessee, Operating Lease, Liability, Payments, Due		700
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(123)
Operating Lease, Liability		577
Finance Lease, Liability, Payment, Due [Abstract]
Finance Lease, Liability, Payments, Due Next Twelve Months		71
Finance Lease, Liability, Payments, Due Year Two		77
Finance Lease, Liability, Payments, Due Year Three		70
Finance Lease, Liability, Payments, Due Year Four		59
Finance Lease, Liability, Payments, Due Year Five		59
Finance Lease, Liability, Payments, Due after Year Five		725
Finance Lease, Liability, Payment, Due		1,061
Finance Lease, Liability, Undiscounted Excess Amount		(542)
Finance Lease, Liability		519
Lease, Liability, Payments, Due Next Twelve Months		218	$ 216	[1]
Lease, Liability, Payments, Due Year Two		203	196	[1]
Lease, Liability, Payments, Due Year Three		172	183	[1]
Lease, Liability, Payments, Due Year Four		132	154	[1]
Lease, Liability, Payments, Due Year Five		109	117	[1]
Lease, Liability, Payments, Due after Year Five		927	931	[1]
Lease, Liability, Payments, Due		1,761	1,797	[1]
Lease, Liability, Undiscounted Excess Amount		(665)
Total Lease Liabilities		1,096
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	[1]		147
Operating Leases, Future Minimum Payments, Due in Two Years	[1]		128
Operating Leases, Future Minimum Payments, Due in Three Years	[1]		110
Operating Leases, Future Minimum Payments, Due in Four Years	[1]		87
Operating Leases, Future Minimum Payments, Due in Five Years	[1]		61
Operating Leases, Future Minimum Payments, Due Thereafter	[1]		159
Operating Leases, Future Minimum Payments Due	[1]		692
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Capital Leases, Future Minimum Payments Due, Next Twelve Months	[1]		69
Capital Leases, Future Minimum Payments Due in Two Years	[1]		68
Capital Leases, Future Minimum Payments Due in Three Years	[1]		73
Capital Leases, Future Minimum Payments Due in Four Years	[1]		67
Capital Leases, Future Minimum Payments Due in Five Years	[1]		56
Capital Leases, Future Minimum Payments Due Thereafter	[1]		772
Capital Leases, Future Minimum Payments Due	[1]		1,105
Sierra Pacific Power Company [Member]
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months		2
Lessee, Operating Lease, Liability, Payments, Due Year Two		2
Lessee, Operating Lease, Liability, Payments, Due Year Three		1
Lessee, Operating Lease, Liability, Payments, Due Year Four		1
Lessee, Operating Lease, Liability, Payments, Due Year Five		1
Lessee, Operating Lease, Liability, Payments, Due after Year Five		26
Lessee, Operating Lease, Liability, Payments, Due		33
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(16)
Operating Lease, Liability		17
Finance Lease, Liability, Payment, Due [Abstract]
Finance Lease, Liability, Payments, Due Next Twelve Months		6
Finance Lease, Liability, Payments, Due Year Two		6
Finance Lease, Liability, Payments, Due Year Three		6
Finance Lease, Liability, Payments, Due Year Four		6
Finance Lease, Liability, Payments, Due Year Five		5
Finance Lease, Liability, Payments, Due after Year Five		46
Finance Lease, Liability, Payment, Due		75
Finance Lease, Liability, Undiscounted Excess Amount		(30)
Finance Lease, Liability		45
Lease, Liability, Payments, Due Next Twelve Months		8	8	[2]
Lease, Liability, Payments, Due Year Two		8	6	[2]
Lease, Liability, Payments, Due Year Three		7	7	[2]
Lease, Liability, Payments, Due Year Four		7	5	[2]
Lease, Liability, Payments, Due Year Five		6	5	[2]
Lease, Liability, Payments, Due after Year Five		72	75	[2]
Lease, Liability, Payments, Due		108	106	[2]
Lease, Liability, Undiscounted Excess Amount		(46)
Total Lease Liabilities		$ 62
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	[2]		2
Operating Leases, Future Minimum Payments, Due in Two Years	[2]		2
Operating Leases, Future Minimum Payments, Due in Three Years	[2]		2
Operating Leases, Future Minimum Payments, Due in Four Years	[2]		1
Operating Leases, Future Minimum Payments, Due in Five Years	[2]		1
Operating Leases, Future Minimum Payments, Due Thereafter	[2]		28
Operating Leases, Future Minimum Payments Due	[2]		36
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Capital Leases, Future Minimum Payments Due, Next Twelve Months	[2]		6
Capital Leases, Future Minimum Payments Due in Two Years	[2]		4
Capital Leases, Future Minimum Payments Due in Three Years	[2]		5
Capital Leases, Future Minimum Payments Due in Four Years	[2]		4
Capital Leases, Future Minimum Payments Due in Five Years	[2]		4
Capital Leases, Future Minimum Payments Due Thereafter	[2]		47
Capital Leases, Future Minimum Payments Due	[2]		$ 70

[1] Amounts included for comparability and accounted for in accordance with ASC Topic 840, "Leases".

[2] (1) Amounts included for comparability and accounted for in accordance with ASC Topic 840, "Leases".