Leases Leases - NPC - Lease Costs (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Variable Lease, Cost	$ 623
Operating Lease, Cost	170
Finance Lease, Right-of-Use Asset, Amortization	16
Finance Lease, Interest Expense	41
Lease, Cost	$ 857
Operating Lease, Weighted Average Remaining Lease Term	7 years 7 months 21 days
Finance Lease, Weighted Average Remaining Lease Term	28 years 10 months 2 days
Operating Lease, Weighted Average Discount Rate, Percent	5.20%
Finance Lease, Weighted Average Discount Rate, Percent	8.60%
Nevada Power Company [Member]
Lessee, Lease, Description [Line Items]
Variable Lease, Cost	$ 434
Operating Lease, Cost	3
Finance Lease, Right-of-Use Asset, Amortization	13
Finance Lease, Interest Expense	37
Lease, Cost	$ 487
Operating Lease, Weighted Average Remaining Lease Term	7 years 5 months 30 days
Finance Lease, Weighted Average Remaining Lease Term	30 years 6 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	4.50%
Finance Lease, Weighted Average Discount Rate, Percent	8.70%