Supplementary information

6 Months Ended

Jun. 30, 2017

Oil and Gas Exploration and Production Industries Disclosures [Abstract]

Supplementary information

Note 15.Supplementary information

Capitalized costs

			June 30,		December 31,
(in millions)			2017		2016
Oil and natural gas properties:
	Proved		$	17,364	$	16,620
	Unproved			2,346		1,856
	Less: accumulated depletion			(7,904)		(7,390)
		Net capitalized costs for oil and natural gas properties	$	11,806	$	11,086

Costs incurred for oil and natural gas producing activities

		Three Months Ended				Six Months Ended
		June 30,				June 30,
(in millions)		2017		2016		2017		2016
Property acquisition costs:
	Proved	$	12	$	4	$	139	$	256
	Unproved		87		19		393		158
Exploration			238		165		473		336
Development			145		107		303		190
	Total costs incurred for oil and natural gas properties	$	482	$	295	$	1,308	$	940