Eastman's obligations are summarized in the following table.



(Dollars in millions)	Payments Due for
Period	Debt Securities		Credit Facilities and Other		Interest Payable		Purchase Obligations		Operating Leases		Other Liabilities		Total
2018	$	—	$	393	$	228	$	230	$	67	$	234	$	1,152
2019	250		1		229		222		55		85		842
2020	797		—		207		184		44		90		1,322
2021	185		200		190		92		34		91		792
2022	738		—		178		160		23		92		1,191
2023 and beyond	3,976		—		1,619		2,032		47		1,056		8,730
Total	$	5,946	$	594	$	2,651	$	2,920	$	270	$	1,648	$	14,029

Estimated future payments of debt securities assumes the repayment of principal upon stated maturity, and actual amounts and the timing of such payments may differ materially due to repayment or other changes in the terms of such debt prior to maturity.

Eastman had various purchase obligations at December 31, 2017 totaling approximately $2.9 billion over a period of approximately 30 years for materials, supplies, and energy incident to the ordinary conduct of business. The Company also had various lease commitments for property and equipment under cancelable, noncancelable, and month-to-month operating leases totaling approximately $270 million over a period of approximately 40 years. Of the total lease commitments, approximately 50 percent relate to real property, including office space, storage facilities, and land; approximately 40 percent relate to railcars; and approximately 10 percent relate to machinery and equipment, including computer and communications equipment and production equipment. Rental expense, net of sublease income, was $94 million, $90 million, and $79 million in 2017, 2016, and 2015, respectively.

Amounts in other liabilities represent the current estimated cash payments required to be made by the Company primarily for pension and other postretirement benefits, environmental loss contingency reserves, accrued compensation benefits, uncertain tax liabilities, one-time transition tax on deferred foreign income under the 2017 Tax Cuts and Jobs Act, and commodity and foreign exchange hedging in the periods indicated. Due to uncertainties in the timing of the effective settlement of tax positions with respect to taxing authorities, management is unable to determine the timing of payments related to uncertain tax liabilities and these amounts are included in the "2023 and beyond" line item.