Leases (Tables)

12 Months Ended

Dec. 31, 2017

Leases [Abstract]

Schedule of Future Minimum Lease Payments

Future minimum lease payments at December 31, 2017, for operating and capital lease obligations were:

	Millions of Dollars
	Capital Lease Obligations		Operating Lease Obligations*
2018	$	22	533
2019	22		420
2020	18		306
2021	18		141
2022	15		100
Remaining years	148		326
Total	243		1,826
Less: income from subleases	—		71
Net minimum lease payments	$	243	1,755
Less: amount representing interest	51
Capital lease obligations	$	192
* Includes the remaining residual value deficiency on our railcar leases. See Note 13—Guarantees, for additional information.

Schedule of Operating Lease Rental Expense

Operating lease rental expense for the years ended December 31 was:

	Millions of Dollars
	2017		2016	2015
Minimum rentals*	$	680	669	641
Contingent rentals	6		6	6
Less: sublease rental income	73		95	136
	$	613	580	511
* Includes expenses related to the residual value deficiency on our railcar leases. See Note 13—Guarantees, for additional information.