14. SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited)

Oil and Gas Operations

The following table sets forth revenue and direct cost information relating to the Company’s oil and gas exploration and production activities. Apache has no long-term agreements to purchase oil or gas production from foreign governments or authorities. In the second quarter of 2015, Apache completed the sale of its Australian LNG business and oil and gas assets, and as such the results of Australia oil and gas assets have been classified as discontinued operations.


	United States		Canada		Egypt⁽³⁾		North Sea		Other International		Total⁽³⁾⁽⁴⁾
	(In millions, except per boe)
2015
Oil and gas production revenues	$	2,637	$	498	$	1,968	$	1,280	$	-	$	6,383

Operating cost:
Depreciation, depletion, and amortization
Recurring⁽¹⁾		1,419		262		1,128		722		-		3,531
Additional		19,537		3,667		281		2,032		-		25,517
Asset retirement obligation accretion		28		43		-		74		-		145
Lease operating expenses		739		244		522		349		-		1,854
Gathering and transportation		68		89		45		9		-		211
Production taxes⁽²⁾		178		23		-		58		-		259
Income tax		(6,863)		(1,000)		(4)		(982)		-		(8,849)

		15,106		3,328		1,972		2,262		-		22,668

Results of operation	$	(12,469)	$	(2,830)	$	(4)	$	(982)	$	-	$	(16,285)

Amortization rate per boe	$	15.49	$	10.61	$	21.29	$	27.77	$	-	$	18.08


2014
Oil and gas production revenues	$	5,744	$	1,092	$	3,539	$	2,316	$	-	$	12,691

Operating cost:
Depreciation, depletion, and amortization
Recurring⁽¹⁾		2,056		343		1,014		975		-		4,388
Additional		4,412		-		-		589		-		5,001
Asset retirement obligation accretion		43		39		-		72		-		154
Lease operating expenses		921		384		499		434		-		2,238
Gathering and transportation		93		123		40		17		-		273
Production taxes⁽²⁾		342		27		-		177		-		546
Income tax		(754)		44		914		32		-		236

		7,113		960		2,467		2,296		-		12,836

Results of operation	$	(1,369)	$	132	$	1,072	$	20	$	-	$	(145)

Amortization rate per boe	$	19.35	$	12.11	$	18.48	$	37.41	$	-	$	20.36


	United States		Canada		Egypt⁽³⁾		North Sea		Other International		Total⁽³⁾⁽⁴⁾
	(In millions, except per boe)

2013
Oil and gas production revenues	$	6,902	$	1,224	$	3,917	$	2,728	$	-	$	14,771

Operating cost:
Depreciation, depletion, and amortization
Recurring⁽¹⁾		2,227		426		881		999		-		4,533
Additional		552		-		-		367		76		995
Asset retirement obligation accretion		94		49		-		68		-		211
Lease operating expenses		1,320		459		471		400		-		2,650
Gathering and transportation		84		155		42		7		-		288
Production taxes⁽²⁾		324		40		-		382		-		746
Income tax		817		24		1,161		313		-		2,315

		5,418		1,153		2,555		2,536		76		11,738

Results of operation	$	1,484	$	71	$	1,362	$	192	$	(76)	$	3,033

Amortization rate per boe	$	18.39	$	10.89	$	16.21	$	37.25	$	-	$	18.77

⁽¹⁾

This amount only reflects DD&A of capitalized costs of oil and gas proved properties and, therefore, does not agree with DD&A reflected on Note 13—Business Segment Information.

⁽²⁾

Only reflects amounts directly related to oil and gas producing properties and, therefore, does not agree with taxes other than income reflected on Note 13—Business Segment Information.

⁽³⁾

Includes noncontrolling interest in Egypt.

⁽⁴⁾

Prior year amounts have been recast to exclude discontinued operations.

Costs Incurred in Oil and Gas Property Acquisitions, Exploration, and Development Activities


	United States		Canada		Egypt⁽²⁾		Australia		North Sea		Argentina		Other International		Total⁽²⁾
	(In millions)
2015
Acquisitions:
Proved	$	1	$	8	$	25	$	1	$	-	$	-	$	-	$	35
Unproved		313		23		4		-		-		-		-		340
Exploration		131		41		110		31		111		-		29		453
Development		1,957		193		764		101		623		-		-		3,638

Costs incurred⁽¹⁾	$	2,402	$	265	$	903	$	133	$	734	$	-	$	29	$	4,466

⁽¹⁾ Includes capitalized interest and asset retirement costs as follows:
Capitalized interest	$	169	$	25	$	17	$	9	$	16	$	-	$	-	$	236
Asset retirement costs		123		8		-		-		(66)		-		-		65

2014
Acquisitions:
Proved	$	102	$	-	$	1	$	1	$	-	$	-	$	-	$	104
Unproved		1,221		141		10		16		-		-		-		1,388
Exploration		467		82		193		137		84		9		1		973
Development		5,301		846		1,142		914		971		6		-		9,180

Costs incurred⁽¹⁾	$	7,091	$	1,069	$	1,346	$	1,068	$	1,055	$	15	$	1	$	11,645

⁽¹⁾ Includes capitalized interest and asset retirement costs as follows:
Capitalized interest	$	209	$	38	$	15	$	20	$	25	$	3	$	-	$	310
Asset retirement costs		43		175		-		55		34		-		-		307

2013
Acquisitions:
Proved	$	17	$	-	$	35	$	-	$	125	$	-	$	-	$	177
Unproved		195		151		15		(10)		17		11		-		379
Exploration		562		36		559		179		278		42		22		1,678
Development		5,435		722		618		996		635		142		-		8,548

Costs incurred⁽¹⁾	$	6,209	$	909	$	1,227	$	1,165	$	1,055	$	195	$	22	$	10,782

⁽¹⁾ Includes capitalized interest and asset retirement costs as follows:
Capitalized interest	$	239	$	35	$	15	$	16	$	25	$	10	$	-	$	340
Asset retirement costs		480		17		-		(30)		67		3		-		537

⁽²⁾ Includes a noncontrolling interest in Egypt.

Capitalized Costs

The following table sets forth the capitalized costs and associated accumulated depreciation, depletion, and amortization, including impairments, relating to the Company’s oil and gas production, exploration, and development activities:


	United States			Canada			Egypt⁽¹⁾			Australia			North Sea			Other International			Total⁽¹⁾
	(In millions)
2015
Proved properties	$	51,693		$	14,613		$	11,296		$	-		$	11,266		$	201		$	89,069
Unproved properties		1,824			234			30			-			471			52			2,611

		53,517			14,847			11,326			-			11,737			253			91,680
Accumulated DD&A		(48,161	)		(13,582	)		(7,779	)		-			(9,129	)		(201	)		(78,852	)

	$	5,356		$	1,265		$	3,547		$	-		$	2,608		$	52		$	12,828


2014
Proved properties	$	47,001		$	14,003		$	9,895		$	8,289		$	10,463		$	201		$	89,852
Unproved properties		4,151			1,090			529			549			672			23			7,014

		51,152			15,093			10,424			8,838			11,135			224			96,866
Accumulated DD&A		(27,205	)		(9,653	)		(6,369	)		(3,198	)		(6,375	)		(201	)		(53,001	)

	$	23,947		$	5,440		$	4,055		$	5,640		$	4,760		$	23		$	43,865

⁽¹⁾ Includes a noncontrolling interest in Egypt.

Costs Not Being Amortized

The following table sets forth a summary of oil and gas property costs not being amortized at December 31, 2015, by the year in which such costs were incurred. There are no individually significant properties or significant development projects included in costs not being amortized. The majority of the evaluation activities are expected to be completed within five to ten years.


	Total		2015		2014		2013		2012 and Prior
	(In millions)
Property acquisition costs	$	1,960	$	316	$	1,311	$	210	$	123
Exploration and development		586		569		15		1		1
Capitalized interest		65		16		13		4		32

Total	$	2,611	$	901	$	1,339	$	215	$	156

Oil and Gas Reserve Information

Proved oil and gas reserves are the estimated quantities of natural gas, crude oil, condensate, and natural gas liquids (NGLs) that geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing conditions, operating conditions, and government regulations. Estimated proved developed oil and gas reserves can be expected to be recovered through existing wells with existing equipment and operating methods. The Company reports all estimated proved reserves held under production-sharing arrangements utilizing the “economic interest” method, which excludes the host country’s share of reserves.

Estimated reserves that can be produced economically through application of improved recovery techniques are included in the “proved” classification when successful testing by a pilot project or the operation of an active, improved recovery program using reliable technology establishes the reasonable certainty for the engineering analysis on which the project or program is based. Economically producible means a resource which generates revenue that exceeds, or is reasonably expected to exceed, the costs of the operation. Reasonable certainty means a high degree of confidence that the quantities will be recovered. Reliable technology is a grouping of one or more technologies (including computational methods) that has been field-tested and has been demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation. In estimating its proved reserves, Apache uses several different traditional methods that can be classified in three general categories: 1) performance-based methods; 2) volumetric-based methods; and 3) analogy with similar properties. Apache will, at times, utilize additional technical analysis such as computer reservoir models, petrophysical techniques, and proprietary 3-D seismic interpretation methods to provide additional support for more complex reservoirs. Information from this additional analysis is combined with traditional methods outlined above to enhance the certainty of our reserve estimates.

There are numerous uncertainties inherent in estimating quantities of proved reserves and projecting future rates of production and timing of development expenditures. The reserve data in the following tables only represent estimates and should not be construed as being exact.


	Crude Oil and Condensate
	(Thousands of barrels)
	United States		Canada		Egypt⁽¹⁾		Australia		North Sea		Argentina		Total⁽¹⁾
Proved developed reserves:
December 31, 2012		474,837		79,695		106,746		29,053		119,635		15,845		825,811
December 31, 2013		457,981		80,526		119,242		22,524		100,327		14,195		794,795
December 31, 2014		444,440		75,876		128,712		29,996		105,746		-		784,770
December 31, 2015		348,797		67,847		144,164		-		104,255		-		665,063
Proved undeveloped reserves:
December 31, 2012		203,068		70,650		17,288		34,808		28,019		2,981		356,814
December 31, 2013		195,835		56,366		16,302		36,703		29,253		2,231		336,690
December 31, 2014		170,125		59,923		14,617		25,775		19,059		-		289,499
December 31, 2015		60,505		38,326		17,856		-		11,309		-		127,996
Total proved reserves:
Balance December 31, 2012		677,905		150,345		124,034		63,861		147,654		18,826		1,182,625
Extensions, discoveries and other additions		133,227		10,177		43,738		2,539		1,543		998		192,222
Purchase of minerals in-place		85		-		5		-		3,623		-		3,713
Revisions of previous estimates		1,683		(531)		457		(118)		18		24		1,533
Production		(53,621)		(6,469)		(32,690)		(7,055)		(23,258)		(3,422)		(126,515)
Sale of properties		(105,463)		(16,630)		-		-		-		-		(122,093)

Balance December 31, 2013		653,816		136,892		135,544		59,227		129,580		16,426		1,131,485
Extensions, discoveries and other additions		57,011		9,657		38,074		4,254		17,386		5		126,387
Purchase of minerals in-place		15,240		-		-		-		-		-		15,240
Revisions of previous estimates		3,083		(812)		1,801		(216)		(7)		-		3,849
Production		(48,789)		(6,421)		(32,090)		(7,494)		(22,154)		(620)		(117,568)
Sale of properties		(65,796)		(3,517)		-		-		-		(15,811)		(85,124)

Balance December 31, 2014		614,565		135,799		143,329		55,771		124,805		-		1,074,269
Extensions, discoveries and other additions		13,903		4,550		24,524		-		16,579		-		59,556
Purchase of minerals in-place		-		1,763		-		-		-		-		1,763
Revisions of previous estimates		(173,907)		(27,966)		25,407		11,189		(2,255)		-		(167,532)
Production		(45,138)		(5,755)		(31,240)		(2,778)		(21,657)		-		(106,568)
Sale of properties		(121)		(2,218)		-		(64,182)		(1,908)		-		(68,429)

Balance December 31, 2015		409,302		106,173		162,020		-		115,564		-		793,059

⁽¹⁾ 2015, 2014, and 2013 includes proved reserves of 54 MMbbls, 48 MMbbls, and 45 MMbbls, respectively, attributable to a noncontrolling interest in Egypt.


	Natural Gas Liquids
	(Thousands of barrels)
	United States		Canada		Egypt⁽¹⁾		Australia		North Sea		Argentina		Total⁽¹⁾
Proved developed reserves:
December 31, 2012		154,508		21,996		-		-		2,438		5,007		183,949
December 31, 2013		184,485		26,099		-		-		2,435		4,110		217,129
December 31, 2014		183,565		17,947		1,346		-		1,770		-		204,628
December 31, 2015		150,265		15,246		1,491		-		1,784		-		168,786
Proved undeveloped reserves:
December 31, 2012		60,889		12,258		-		-		380		876		74,403
December 31, 2013		63,538		9,970		-		-		215		1,009		74,732
December 31, 2014		69,828		7,168		212		-		371		-		77,579
December 31, 2015		24,939		4,839		78		-		295		-		30,151
Total proved reserves:
Balance December 31, 2012		215,397		34,254		-		-		2,818		5,883		258,352
Extensions, discoveries and other additions		69,231		4,014		-		-		-		-		73,245
Purchase of minerals in-place		45		-		-		-		295		-		340
Revisions of previous estimates		1,591		546		-		-		1		3		2,141
Production		(19,922)		(2,442)		-		-		(464)		(767)		(23,595)
Sale of properties		(18,319)		(303)		-		-		-		-		(18,622)

Balance December 31, 2013		248,023		36,069		-		-		2,650		5,119		291,861
Extensions, discoveries and other additions		47,516		1,163		1,820		-		1		-		50,500
Purchase of minerals in-place		2,916		-		-		-		-		-		2,916
Revisions of previous estimates		2,594		116		(17)		-		(2)		-		2,691
Production		(21,464)		(2,256)		(245)		-		(508)		(116)		(24,589)
Sale of properties		(26,192)		(9,977)		-		-		-		(5,003)		(41,172)

Balance December 31, 2014		253,393		25,115		1,558		-		2,141		-		282,207
Extensions, discoveries and other additions		5,768		1,473		144		-		689		-		8,074
Purchase of minerals in-place		-		976		-		-		-		-		976
Revisions of previous estimates		(64,226)		(4,886)		255		-		(321)		-		(69,178)
Production		(19,684)		(2,236)		(388)		-		(413)		-		(22,721)
Sale of properties		(47)		(357)		-		-		(17)		-		(421)

Balance December 31, 2015		175,204		20,085		1,569		-		2,079		-		198,937

⁽¹⁾ 2015 and 2014 includes proved reserves of 523 Mbbls and 519 Mbbls, respectively, attributable to a noncontrolling interest in Egypt.


	Natural Gas
	(Millions of cubic feet)
	United States		Canada		Egypt⁽¹⁾		Australia		North Sea		Argentina		Total⁽¹⁾
Proved developed reserves:
December 31, 2012		2,353,587		1,734,657		690,436		596,052		93,319		365,054		5,833,105
December 31, 2013		2,005,966		1,294,420		621,825		626,543		88,177		289,133		4,926,064
December 31, 2014		1,616,504		990,145		637,187		640,265		87,259		-		3,971,360
December 31, 2015		1,364,174		759,321		776,263		-		85,532		-		2,985,290
Proved undeveloped reserves:
December 31, 2012		832,320		403,227		205,055		1,074,018		18,985		97,496		2,631,101
December 31, 2013		667,160		439,037		190,355		975,224		18,988		121,584		2,412,348
December 31, 2014		580,299		527,623		171,696		964,554		23,228		-		2,267,400
December 31, 2015		208,594		162,809		53,969		-		19,760		-		445,132
Total proved reserves:
Balance December 31, 2012		3,185,907		2,137,884		895,491		1,670,070		112,304		462,550		8,464,206
Extensions, discoveries and other additions		306,721		359,493		44,382		13,351		2,750		16,515		743,212
Purchase of minerals in-place		855		-		-		-		10,680		-		11,535
Revisions of previous estimates		61,247		109,551		2,413		(101)		32		49		173,191
Production		(285,187)		(181,593)		(130,106)		(81,553)		(18,601)		(68,397)		(765,437)

Sale of properties		(596,417)		(691,878)		-		-		-		-		(1,288,295)

Balance December 31, 2013		2,673,126		1,733,457		812,180		1,601,767		107,165		410,717		7,338,412
Extensions, discoveries and other additions		203,318		383,077		125,899		81,156		23,803		-		817,253
Purchase of minerals in-place		21,337		-		-		-		-		-		21,337
Revisions of previous estimates		35,910		(12,626)		5,949		-		(54)		-		29,179
Production		(215,829)		(117,816)		(135,145)		(78,104)		(20,427)		(12,722)		(580,043)
Sale of properties		(521,059)		(468,324)		-		-		-		(397,995)		(1,387,378)

Balance December 31, 2014		2,196,803		1,517,768		808,883		1,604,819		110,487		-		6,238,760
Extensions, discoveries and other additions		40,901		121,216		94,777		-		41,755		-		298,649
Purchase of minerals in-place		-		24,727		-		-		-		-		24,727
Revisions of previous estimates		(503,939)		(325,375)		54,811		8,162		(22,373)		-		(788,714)
Production		(160,614)		(100,289)		(128,239)		(34,352)		(23,647)		-		(447,141)

Sale of properties		(383)		(315,917)		-		(1,578,629)		(930)		-		(1,895,859)

Balance December 31, 2015		1,572,768		922,130		830,232		-		105,292		-		3,430,422

⁽¹⁾ 2015, 2014, and 2013 include proved reserves of 277 Bcf, 270 Bcf, and 271 Bcf, respectively, attributable to a noncontrolling interest in Egypt.


	Total Equivalent Reserves
	(Thousands barrels of oil equivalent)
	United States		Canada		Egypt⁽¹⁾		Australia		North Sea		Argentina		Total⁽¹⁾
Proved developed reserves:
December 31, 2012		1,021,610		390,800		221,819		128,395		137,626		81,695		1,981,945
December 31, 2013		976,795		322,362		222,880		126,948		117,457		66,494		1,832,936
December 31, 2014		897,422		258,848		236,256		136,707		122,058		-		1,651,291
December 31, 2015		726,424		209,647		275,033		-		120,293		-		1,331,397
Proved undeveloped reserves:
December 31, 2012		402,677		150,113		51,464		213,811		31,563		20,106		869,734
December 31, 2013		370,566		139,509		48,028		199,240		32,633		23,504		813,480
December 31, 2014		336,670		155,028		43,446		186,534		23,301		-		744,979
December 31, 2015		120,210		70,300		26,929		-		14,897		-		232,336
Total proved reserves:
Balance December 31, 2012		1,424,287		540,913		273,283		342,206		169,189		101,801		2,851,679
Extensions, discoveries and other additions		253,578		74,107		51,135		4,764		2,001		3,751		389,336
Purchase of minerals in-place		273		-		5		-		5,698		-		5,976
Revisions of previous estimates		13,482		18,274		859		(135)		24		35		32,539
Production		(121,074)		(39,177)		(54,374)		(20,647)		(26,822)		(15,589)		(277,683)
Sale of properties		(223,185)		(132,246)		-		-		-		-		(355,431)

Balance December 31, 2013		1,347,361		461,871		270,908		326,188		150,090		89,998		2,646,416
Extensions, discoveries and other additions		138,413		74,666		60,877		17,780		21,354		5		313,095
Purchase of minerals in-place		21,712		-		-		-		-		-		21,712
Revisions of previous estimates		11,662		(2,800)		2,776		(216)		(18)		-		11,404
Production		(106,225)		(28,313)		(54,859)		(20,511)		(26,067)		(2,856)		(238,831)
Sale of properties		(178,831)		(91,548)		-		-		-		(87,147)		(357,526)

Balance December 31, 2014		1,234,092		413,876		279,702		323,241		145,359		-		2,396,270
Extensions, discoveries and other additions		26,488		26,226		40,464		-		24,227		-		117,405
Purchase of minerals in-place		-		6,860		-		-		-		-		6,860
Revisions of previous estimates		(322,123)		(87,081)		34,797		12,549		(6,305)		-		(368,163)
Production		(91,591)		(24,706)		(53,001)		(8,503)		(26,011)		-		(203,812)
Sale of properties		(232)		(55,228)		-		(327,287)		(2,080)		-		(384,827)

Balance December 31, 2015		846,634		279,947		301,962		-		135,190		-		1,563,733

⁽¹⁾ 2015, 2014, and 2013 include total proved reserves of 101 MMboe, 93 MMboe, and 90 MMboe, respectively, attributable to a noncontrolling interest in Egypt.

During 2015, Apache sold a combined 385 MMboe through several divestiture transactions: 55 MMboe in Canada, 328 MMboe in Australia, and 2 MMboe in the North Sea. The Company added 7 MMboe of estimated proved reserves through purchases of minerals in-place and 117 MMboe from extensions, discoveries, and other additions. The Company recorded 53 MMboe in North America, primarily associated with our drilling programs in the Canadian liquid-rich gas targets of Duvernay and Montney formations and Permian Basin drilling for Wolfcamp, Yeso, Lower Spraberry, and Bone Spring formations. The Company also had additional drilling success in the Woodford, Canyon Lime, Marmaton, and Eagle Ford formations in the MidContinent/Gulf Coast region.

The international regions contributed 64 MMboe of exploration and development adds with Egypt contributing 40 MMboe from onshore exploration and appraisal activity in the West Kalabsha, Shushan, and Khalda concessions. Egypt also continued development of the Ptah, Berenice, and Razzak fields during 2015. The North Sea offshore region contributed 24 MMboe from exploration success in the Callater discovery and continued development in the Beryl, Forties, and Nevis fields.

During 2015, Apache also had combined downward revisions of previously estimated reserves of 368 MMboe. Changes in product prices accounted for 339 MMboe, lease ownership changes accounted for 16 MMboe, and engineering and performance revisions totaled 13 MMboe.

Approximately 9 percent of Apache’s year-end 2015 estimated proved developed reserves are classified as proved not producing. These reserves relate to zones that are either behind pipe, or that have been completed but not yet produced, or zones that have been produced in the past, but are not now producing because of mechanical reasons. These reserves are considered to be a lower tier of reserves than producing reserves because they are frequently based on volumetric calculations rather than performance data. Future production associated with behind pipe reserves is scheduled to follow depletion of the currently producing zones in the same wellbores. Additional capital may have to be spent to access these reserves. The capital and economic impact of production timing are reflected in this Note 14, under “Future Net Cash Flows.”

Future Net Cash Flows

Future cash inflows as of December 31, 2015 and 2014 were calculated using an unweighted arithmetic average of oil and gas prices in effect on the first day of each month in the respective year, except where prices are defined by contractual arrangements. Operating costs, production and ad valorem taxes and future development costs are based on current costs with no escalation.

The following table sets forth unaudited information concerning future net cash flows for proved oil and gas reserves, net of income tax expense. Income tax expense has been computed using expected future tax rates and giving effect to tax deductions and credits available, under current laws, and which relate to oil and gas producing activities. This information does not purport to present the fair market value of the Company’s oil and gas assets, but does present a standardized disclosure concerning possible future net cash flows that would result under the assumptions used.


	United States		Canada		Egypt⁽²⁾		Australia		North Sea		Total⁽²⁾
	(In millions)
2015
Cash inflows	$	26,610	$	7,345	$	11,124	$	-	$	6,994	$	52,073
Production costs		(12,178)		(3,841)		(2,185)		-		(3,209)		(21,413)
Development costs		(2,255)		(1,939)		(1,515)		-		(2,346)		(8,055)
Income tax expense		(63)		-		(2,326)		-		(691)		(3,080)

Net cash flows		12,114		1,565		5,098		-		748		19,525
10 percent discount rate		(6,876)		(868)		(1,330)		-		143		(8,931)

Discounted future net cash flows⁽¹⁾	$	5,238	$	697	$	3,768	$	-	$	891	$	10,594


2014
Cash inflows	$	73,859	$	18,966	$	16,802	$	19,391	$	13,916	$	142,934
Production costs		(25,875)		(7,537)		(2,924)		(4,105)		(7,121)		(47,562)
Development costs		(4,422)		(2,453)		(1,683)		(1,173)		(2,776)		(12,507)
Income tax expense		(10,657)		(1,070)		(4,091)		(3,202)		(2,445)		(21,465)

Net cash flows		32,905		7,906		8,104		10,911		1,574		61,400
10 percent discount rate		(17,639)		(3,983)		(2,099)		(5,875)		(146)		(29,742)

Discounted future net cash flows⁽¹⁾	$	15,266	$	3,923	$	6,005	$	5,036	$	1,428	$	31,658

⁽¹⁾

Estimated future net cash flows before income tax expense, discounted at 10 percent per annum, totaled approximately $13.1 billion and $43.0 billion as of December 31, 2015 and 2014, respectively.

⁽²⁾

Includes discounted future net cash flows of approximately $1.3 billion and $2.0 billion in 2015 and 2014, respectively, attributable to a noncontrolling interest in Egypt.

The following table sets forth the principal sources of change in the discounted future net cash flows:


	For the Year Ended December 31,
	2015		2014		2013
	(In millions)
Sales, net of production costs	$	(4,056)	$	(10,350)	$	(12,271)
Net change in prices and production costs		(21,710)		(1,029)		1,438
Discoveries and improved recovery, net of related costs		1,953		6,297		6,892
Change in future development costs		705		(1,136)		(2,017)
Previously estimated development costs incurred during the period		1,991		4,462		4,654
Revision of quantities		(2,292)		256		500
Purchases of minerals in-place		22		508		227
Accretion of discount		3,642		4,442		4,823
Change in income taxes		7,264		836		855
Sales of properties		(5,240)		(4,780)		(6,232)
Change in production rates and other		(3,343)		(442)		(828)

	$	(21,064)	$	(936)	$	(1,959)