Management records a right-of-use asset and lease liability for several types of operating leases, including land and buildings, alumina refinery process control technology, plant equipment, vehicles, and computer equipment. The leases have remaining terms of less than one to 37 years. The discount rate applied to these leases is the Company’s incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments, unless there is a rate implicit in the lease agreement. The Company does not have material financing leases.

	First quarter ended March 31,
	2021		2020
Costs from operating leases	$	21	$	18
Variable lease payments	$	1	$	4
Short-term rental expense	$	—	$	1

The weighted average lease term and weighted average discount rate as of March 31, 2021 and December 31, 2020 were as follows:

	March 31, 2021		December 31, 2020
Weighted average lease term for operating leases (years)		4.7		4.4
Weighted average discount rate for operating leases	5.2%		5.2%

The following represents the aggregate right-of use assets and related lease obligations recognized in the Consolidated Balance Sheet at:

	March 31, 2021		December 31, 2020
Properties, plants and equipment, net	$	131	$	137
Other current liabilities	$	54	$	60
Other noncurrent liabilities and deferred credits		80		82
Total operating lease liabilities	$	134	$	142

Right-of-use assets and lease liabilities related to the Warrick Rolling Mill were excluded from the December 31, 2020 balances in the above table due to the sale of the rolling mill and were reclassified to Assets held for sale (see Note C).

New leases of $8 were added during the first quarter of 2021.

The future cash flows related to the operating lease obligations as of March 31, 2021 were as follows:

2021 (excluding the three months ended March 31)	$	47
2022		35
2023		23
2024		14
2025		9
Thereafter		24
Total lease payments (undiscounted)		152
Less: discount to net present value		(18	)
Total	$	134