Leases Leases - NPC - 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
Nevada Power Company [Member]
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months		3
Lessee, Operating Lease, Liability, Payments, Due Year Two		3
Lessee, Operating Lease, Liability, Payments, Due Year Three		3
Lessee, Operating Lease, Liability, Payments, Due Year Four		2
Lessee, Operating Lease, Liability, Payments, Due Year Five		2
Lessee, Operating Lease, Liability, Payments, Due after Year Five		7
Lessee, Operating Lease, Liability, Payments, Due		20
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(3)
Operating Lease, Liability		17
Finance Lease, Liability, Payment, Due [Abstract]
Finance Lease, Liability, Payments, Due Next Twelve Months		60
Finance Lease, Liability, Payments, Due Year Two		64
Finance Lease, Liability, Payments, Due Year Three		62
Finance Lease, Liability, Payments, Due Year Four		51
Finance Lease, Liability, Payments, Due Year Five		52
Finance Lease, Liability, Payments, Due after Year Five		664
Finance Lease, Liability, Payment, Due		953
Finance Lease, Liability, Undiscounted Excess Amount		(499)
Finance Lease, Liability		454
Lease, Liability, Payments, Due Next Twelve Months		63	62	[1]
Lease, Liability, Payments, Due Year Two		67	62	[1]
Lease, Liability, Payments, Due Year Three		65	64	[1]
Lease, Liability, Payments, Due Year Four		53	63	[1]
Lease, Liability, Payments, Due Year Five		54	52	[1]
Lease, Liability, Payments, Due after Year Five		671	719	[1]
Lease, Liability, Payments, Due		973	1,022	[1]
Lease, Liability, Undiscounted Excess Amount		(502)
Total Lease Liabilities		$ 471
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	[1]		3
Operating Leases, Future Minimum Payments, Due in Two Years	[1]		3
Operating Leases, Future Minimum Payments, Due in Three Years	[1]		3
Operating Leases, Future Minimum Payments, Due in Four Years	[1]		3
Operating Leases, Future Minimum Payments, Due in Five Years	[1]		2
Operating Leases, Future Minimum Payments, Due Thereafter	[1]		10
Operating Leases, Future Minimum Payments Due	[1]		24
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Capital Leases, Future Minimum Payments Due, Next Twelve Months	[1]		59
Capital Leases, Future Minimum Payments Due in Two Years	[1]		59
Capital Leases, Future Minimum Payments Due in Three Years	[1]		61
Capital Leases, Future Minimum Payments Due in Four Years	[1]		60
Capital Leases, Future Minimum Payments Due in Five Years	[1]		50
Capital Leases, Future Minimum Payments Due Thereafter	[1]		709
Capital Leases, Future Minimum Payments Due	[1]		$ 998

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