Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Schedule of Non-cash Impairments of Proved and Unproved Property and Equipment

The following table represents non-cash impairments of the carrying value of the Company’s proved and unproved property and equipment for the second quarters and first six months of 2017 and 2016:

	Quarter Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
	(In millions)
Oil and Gas Property:
Proved	$	—	$	68	$	—	$	68
Unproved	39		66		54		108