Impairments (Tables)

3 Months Ended

Mar. 31, 2019

Impairment Expense [Abstract]

Fair Value Measurements, Nonrecurring

The following table summarizes impairment charges of proved properties. Additionally, it presents the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition.

	Three Months Ended March 31,
	2019				2018
(In millions)	Fair Value		Impairment		Fair Value		Impairment
Long-lived assets held for use	$	37	$	6	$	50	$	8

Exploration Expenses

The following table summarizes impairment charges of unproved properties included as a component of exploration expense:

	Three Months Ended March 31,
(In millions)	2019		2018
Exploration Expenses
Unproved property impairments	$	44	$	40
Dry well costs	5		2
Geological and geophysical	6		6
Other	4		4
Total exploration expenses	$	59	$	52