Inventories (Tables)

12 Months Ended

Dec. 31, 2021

Inventories [Abstract]

Schedule of Inventories

Inventories at December 31 were:

Millions of Dollars

2021

2020

Crude oil and natural gas

$

647

461

Materials and supplies

561

541

Total inventories

$

1,208

1,002

Inventories valued on the LIFO basis

$

395

282