Impairments (Tables)

3 Months Ended

Mar. 31, 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
millions	Impairment		Fair Value (1)
March 31, 2016
Oil and gas exploration and production
Long-lived assets held for use
U.S. onshore properties	$	4	$	585
Gulf of Mexico properties	1		—
Cost-method investment (2)	1		32
Midstream
Long-lived assets held for use	10		3
Total	$	16	$	620
March 31, 2015
Oil and gas exploration and production
Long-lived assets held for use
U.S. onshore properties	$	2,307	$	1,299
Midstream
Long-lived assets held for use	476		206
Total	$	2,783	$	1,505

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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.