Impairments (Tables)

9 Months Ended

Sep. 30, 2016

Asset Impairment Charges [Abstract]

Schedule of Impairment Expense

The following summarizes impairments of long-lived assets and the related post-impairment fair values by segment:

	Three Months Ended				Nine Months Ended
millions	Impairment		Fair Value (1)		Impairment		Fair Value (1)
September 30, 2016
Oil and gas exploration and production
Long-lived assets held for use
U.S. onshore properties	$	23	$	32	$	27	$	617
Gulf of Mexico properties	—		—		2		—
Cost-method investment (2)	—		—		2		32
Midstream
Long-lived assets held for use	3		—		24		5
Other
Long-lived assets held for use	1		—		6		—
Total	$	27	$	32	$	61	$	654
September 30, 2015
Oil and gas exploration and production
Long-lived assets held for use
U.S. onshore properties	$	641	$	634	$	2,944	$	1,904
Gulf of Mexico properties	101		94		126		94
Cost-method investment (2)	1		32		2		32
Midstream
Long-lived assets held for use	15		7		499		209
Total	$	758	$	767	$	3,571	$	2,239

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⁽¹⁾  Measured as of the impairment date using the income approach and Level 3 inputs.

⁽²⁾  Represents the after-tax net investment.