Impairments (Tables)

12 Months Ended

Dec. 31, 2018

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 at December 31:

	2018						2017						2016
millions	Impairment			Fair Value (1)			Impairment			Fair Value (1)			Impairment			Fair Value (1)
Exploration and Production
U.S. onshore properties		$	397		$	172		$	2		$	3		$	28		$	617
Gulf of Mexico properties		27			—			227			216			27			61
Cost-method investment		—			—			—			—			59			—
WES Midstream		231			30			178			58			18			3
Other		145			15			1			—			95			29
Total impairments		$	800		$	217		$	408		$	277		$	227		$	710

⁽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.