Impairments (Tables)

9 Months Ended

Sep. 30, 2017

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:

	Nine Months Ended
millions	Impairment		Fair Value (1)
September 30, 2017
Exploration and Production
U.S. onshore properties	$	2	$	3
Gulf of Mexico properties	211		231
Midstream	169		58
Other	1		—
Total	$	383	$	292

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⁽¹⁾  Measured as of the impairment date using the income approach and Level 3 inputs. The primary assumptions used to estimate undiscounted future net cash flows include anticipated future production, commodity prices, and capital and operating costs.