Supplementary information

9 Months Ended

Sep. 30, 2017

Oil and Gas Exploration and Production Industries Disclosures [Abstract]

Supplementary information

Note 15.Supplementary information

Capitalized costs

			September 30,		December 31,
(in millions)			2017		2016
Oil and natural gas properties:
	Proved		$	17,950	$	16,620
	Unproved			2,804		1,856
	Less: accumulated depletion			(8,167)		(7,390)
		Net capitalized costs for oil and natural gas properties	$	12,587	$	11,086

Costs incurred for oil and natural gas producing activities

		Three Months Ended				Nine Months Ended
		September 30,				September 30,
(in millions)		2017		2016		2017		2016
Property acquisition costs:
	Proved	$	162	$	1	$	301	$	257
	Unproved		472		14		865		172
Exploration			252		177		725		513
Development			175		97		478		287
	Total costs incurred for oil and natural gas properties	$	1,061	$	289	$	2,369	$	1,229