Inventories

12 Months Ended

Dec. 31, 2019

Inventory Disclosure [Abstract]

Inventories

Inventories

Inventories at December 31 consisted of the following:

	Millions of Dollars
	2019		2018
Crude oil and petroleum products	$	3,452	3,238
Materials and supplies	324		305
	$	3,776	3,543

Inventories valued on the LIFO basis totaled $3,331 million and $3,123 million at December 31, 2019 and 2018, respectively. The estimated excess of current replacement cost over LIFO cost of inventories amounted to approximately $4.3 billion and $2.9 billion at December 31, 2019 and 2018, respectively.

LIFO inventory liquidations did not have a material impact on net income for the years ended December 31, 2019, 2018 and 2017.