Leases (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Finance Lease, Right-of-Use Asset, Amortization		$ 2	$ 3
Finance Lease, Interest Expense		4	5
Finance Lease, Cost		6	8
Operating Lease, Cost	[1]	66	54
Lessee, Operating Lease, Liability, to be Paid		1,793
Finance Lease, Liability, Payment, Due	[2]	253
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(285)
Finance Lease, Liability, Undiscounted Excess Amount	[2]	(178)
Operating Lease, Liability		1,508
Finance Lease, Liability	[2]	75
Operating Lease, Liability, Current		(221)		$ (214)
Finance Lease, Liability, Current	[2]	(4)
Operating lease liabilities		1,287		$ 1,344
Finance Lease, Liability, Noncurrent	[2]	71
Short-term Lease, Cost		1	1
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		58	46
Lessee, Operating Lease, Liability, to be Paid		1,592
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(248)
Operating Lease, Liability		1,344
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[3]	8	$ 8
Lessee, Operating Lease, Liability, to be Paid		201
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(37)
Operating Lease, Liability		$ 164

[1] PPA capacity payments are included in electric fuel and purchased power on the consolidated statements of income. Expense for other operating leases is included in O&M expense and electric fuel and purchased power.

[2] Excludes certain amounts related to Xcel Energy’s 50% ownership interest in WYCO.

[3] Includes short-term lease expense of $1 million and $1 million for 2021 and 2020, respectively.