We have entered into various operating and finance lease agreements for certain of our offices, manufacturing and warehouse facilities, retail and service locations, equipment, vehicles, and solar energy systems, worldwide. We determine if an arrangement is a lease, or contains a lease, at inception and record the leases in our financial statements upon lease commencement, which is the date when the underlying asset is made available for use by the lessor.

We have lease agreements with lease and non-lease components, and have elected to utilize the practical expedient to account for lease and non-lease components together as a single combined lease component, from both a lessee and lessor perspective with the exception of direct sales-type leases and production equipment classes embedded in supply agreements. From a lessor perspective, the timing and pattern of transfer are the same for the non-lease components and associated lease component and, the lease component, if accounted for separately, would be classified as an operating lease.

We have elected not to present short-term leases on the consolidated balance sheet as these leases have a lease term of 12 months or less at lease inception and do not contain purchase options or renewal terms that we are reasonably certain to exercise. All other lease assets and lease liabilities are recognized based on the present value of lease payments over the lease term at commencement date. Because most of our leases do not provide an implicit rate of return, we used our incremental borrowing rate based on the information available at lease commencement date in determining the present value of lease payments.

Our leases, where we are the lessee, often include options to extend the lease term for up to 10 years. Some of our leases also include options to terminate the lease prior to the end of the agreed upon lease term. For purposes of calculating lease liabilities, lease terms include options to extend or terminate the lease when it is reasonably certain that we will exercise such options.

Lease expense for operating leases is recognized on a straight-line basis over the lease term as cost of revenues or operating expenses depending on the nature of the leased asset. Certain operating leases provide for annual increases to lease payments based on an index or rate. We calculate the present value of future lease payments based on the index or rate at the lease commencement date for new leases commencing after January 1, 2019. For historical leases, we used the index or rate as of January 1, 2019. Differences between the calculated lease payment and actual payment are expensed as incurred. Amortization of finance lease assets is recognized over the lease term as cost of revenues or operating expenses depending on the nature of the leased asset. Interest expense on finance lease liabilities is recognized over the lease term in interest expense.

The balances for the operating and finance leases where we are the lessee are presented as follows (in millions) within our consolidated balance sheet:

	December 31, 2020		December 31, 2019
Operating leases:
Operating lease right-of-use assets	$	1,558	$	1,218

Accrued liabilities and other	$	286	$	228
Other long-term liabilities		1,254		956
Total operating lease liabilities	$	1,540	$	1,184

Finance leases:
Solar energy systems, net	$	29	$	30
Property, plant and equipment, net		1,465		1,600
Total finance lease assets	$	1,494	$	1,630

Current portion of long-term debt and finance leases	$	374	$	386
Long-term debt and finance leases, net of current portion		1,094		1,232
Total finance lease liabilities	$	1,468	$	1,618

The components of lease expense are as follows (in millions) within our consolidated statements of operations:

	Year Ended
	December 31, 2020		December 31, 2019
Operating lease expense:
Operating lease expense (1)	$	451	$	426

Finance lease expense:
Amortization of leased assets	$	348	$	299
Interest on lease liabilities		100		104
Total finance lease expense	$	448	$	403

Total lease expense	$	899	$	829

	December 31, 2020			December 31, 2019
Weighted-average remaining lease term:
Operating leases	6.2 years			6.2 years
Finance leases	4.9 years			3.9 years

Weighted-average discount rate:
Operating leases		5.8	%		6.5	%
Finance leases		6.5	%		6.5	%

Supplemental cash flow information related to leases where we are the lessee is as follows (in millions):

	Year Ended
	December 31, 2020		December 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows from operating leases	$	456	$	396
Operating cash outflows from finance leases (interest payments)	$	100	$	104
Financing cash outflows from finance leases	$	338	$	321
Leased assets obtained in exchange for finance lease liabilities	$	188	$	616
Leased assets obtained in exchange for operating lease liabilities	$	553	$	202

As of December 31, 2020, the maturities of our operating and finance lease liabilities (excluding short-term leases) are as follows (in millions):

	Operating		Finance
	Leases		Leases
2021	$	366	$	462
2022		327		446
2023		279		412
2024		245		299
2025		204		9
Thereafter		425		7
Total minimum lease payments		1,846		1,635
Less: Interest		306		167
Present value of lease obligations		1,540		1,468
Less: Current portion		286		374
Long-term portion of lease obligations	$	1,254	$	1,094

We are the lessor of certain vehicle and solar energy system arrangements as described in Note 2, Summary of Significant Accounting Policies. As of December 31, 2020, maturities of our operating lease and sales-type lease receivables from customers for each of the next five years and thereafter were as follows (in millions):

	Operating		Sales-type
	Leases		Leases
2021	$	774	$	21
2022		594		21
2023		351		21
2024		206		30
2025		191		5
Thereafter		2,102		4
Gross lease receivables	$	4,218	$	102

The above table does not include vehicle sales to customers or leasing partners with a resale value guarantee as the cash payments were received upfront. For our solar PPA arrangements, customers are charged solely based on actual power produced by the installed solar energy system at a predefined rate per kilowatt-hour of power produced. The future payments from such arrangements are not included in the above table as they are a function of the power generated by the related solar energy systems in the future.

Net investment in sales-type leases, which is the sum of the present value of the future contractual lease payments, is presented on the consolidated balance sheet as a component of prepaid expenses and other current assets for the current portion and as other assets for the long-term portion. We introduced sales-type leasing programs in volume during the third quarter of 2020 and therefore have no associated balances as of December 31, 2019. Lease receivables relating to sales-type leases are presented on the consolidated balance sheet as follows (in millions):

	December 31,
	2020
Gross lease receivables	$	102
Unearned interest income		(11	)
Net investment in sales-type leases	$	91

Reported as:
Prepaid expenses and other current assets	$	17
Other assets		74
Net investment in sales-type leases	$	91