Inventories

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories

Crude oil and natural gas are recorded at weighted average cost and carried at the lower of cost or net realizable value. Supplies and other items consist principally of tubular goods and equipment which are valued at weighted average cost and reviewed periodically for obsolescence or impairment when market conditions indicate.

	December 31,
(In millions)	2018		2017
Crude oil and natural gas	$	11	$	9
Supplies and other items	85		117
Inventories	$	96	$	126