Commitment and Contingencies (Tables)

3 Months Ended

Mar. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Schedule of Components of Lease Expense

Components of lease expense:

	Three Months Ended March 31
(Millions of Dollars)	2021		2020
Operating leases
PPA capacity payments	$	26	$	25
Other operating leases (a)	4		3
Total operating lease expense (b)	$	30	$	28
Finance leases
Amortization of ROU assets	$	2	$	3
Interest expense on lease liability	4		5
Total finance lease expense	$	6	$	8

(a)Includes immaterial short-term lease expense for 2021 and 2020.

(b)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.

Schedule of Future Commitments under Operating Leases

Commitments under operating and finance leases as of March 31, 2021:

(Millions of Dollars)	PPA Operating Leases		Other Operating Lease		Total Operating Leases		Finance Leases
Total minimum obligation	$	518	$	64	$	582	$	478
Interest component of obligation	(70)		(7)		(77)		(348)
Present value of minimum obligation	$	448	$	57	505		130
Less current portion					(100)		(6)
Noncurrent operating and finance lease liabilities					$	405	$	124