LEASES

The Company leases certain land, buildings and equipment under noncancellable operating leases that expire at various dates through 2036. Capital leases as of December 31, 2015, are not considered material. Many of the building leases obligate the Company to pay real estate taxes, insurance and certain maintenance costs, and contain multiple renewal provisions, exercisable at the Company's option. Leases that contain predetermined fixed escalations of the minimum rentals are recognized in rental expense on a straight-line basis over the lease term. Cash or rent abatements received upon entering into certain operating leases are also recognized on a straight-line basis over the lease term.

At December 31, 2015, the approximate future minimum lease payments for all operating leases were as follows (in thousands of dollars):



Year	Future Minimum Lease Payments
2016	$	66,864
2017	42,255
2018	27,801
2019	18,327
2020	6,143
Thereafter	13,328
Total minimum payments required	174,718
Less amounts representing sublease income	(3,021		)
	$	171,697

Rent expense, including items under lease and items rented on a month-to-month basis, was $77 million for 2015 and 2014, and $68 million for 2013. These amounts are net of sublease income of $2 million for 2015 and 2014, and $1 million for 2013.