Inventories (Notes)

9 Months Ended

Sep. 30, 2017

Inventory Disclosure [Abstract]

Inventories [Text Block]

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.

	September 30,		December 31,
(In millions)	2017		2016
Crude oil and natural gas	$	9	$	6
Supplies and other items	123		130
Inventories	$	132	$	136