Impairments and Exploration Expense (Tables)

9 Months Ended

Sep. 30, 2017

Impairments and Exploration Expense [Abstract]

Details of Impairment of Long-Lived Assets Held and Used by Asset [Table Text Block]

The following table summarizes impairment charges of proved properties from continuing operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in millions)	2017		2016		2017		2016
Total impairments	$	201	$	47	$	205	$	48

Exploration Expenses [Table Text Block]

The following table summarizes the components of exploration expenses:

	Three Months Ended September 30,				Nine Months Ended September 30,
(In millions)	2017		2016		2017		2016
Exploration Expenses
Unproved property impairments	$	172	$	28	$	217	$	172
Dry well costs	77		9		77		24
Geological and geophysical	2		1		3		1
Other	43		45		55		92
Total exploration expenses	$	294	$	83	$	352	$	289