Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit)

The following summarizes components of income tax expense (benefit) for the years ended December 31:

millions	2017			2016			2015
Current
Federal	$	236		$	(140	)	$	(177	)
State	48			(1		)	(18		)
Foreign	414			378			495
	698			237			300
Deferred
Federal	(2,082		)	(1,020		)	(2,929		)
State	(17		)	(148		)	(145		)
Foreign	(76		)	(90		)	(103		)
	(2,175		)	(1,258		)	(3,177		)
Total income tax expense (benefit)	$	(1,477	)	$	(1,021	)	$	(2,877	)

Schedule of Effective Income Tax Rate Reconciliation

The following summarizes the sources of these differences for the years ended December 31:

millions except percentages	2017			2016			2015
Income (loss) before income taxes
Domestic	$	(1,322	)	$	(3,728	)	$	(9,155	)
Foreign	(366		)	(101		)	(534		)
Total	$	(1,688	)	$	(3,829	)	$	(9,689	)
U.S. federal statutory tax rate	35		%	35		%	35		%
Tax computed at the U.S. federal statutory rate	$	(591	)	$	(1,340	)	$	(3,391	)
(Income) loss attributable to noncontrolling interests	(85		)	(92		)	42
Adjustments resulting from
State income taxes (net of federal income tax benefit)	25			(108		)	(81		)
U.S. federal tax reform	(1,168		)	—			—
Tax impact from foreign operations	166			80			299
Non-deductible Algerian exceptional profits tax	110			106			102
Net changes in uncertain tax positions	90			90			54
Dispositions of non-deductible goodwill	6			205			62
Other, net	(30		)	38			36
Total income tax expense (benefit)	$	(1,477	)	$	(1,021	)	$	(2,877	)
Effective tax rate	88		%	27		%	30		%

Deferred Tax Assets (Liabilities) Table

The following summarizes components of total deferred taxes at December 31:

millions	2017			2016
Federal	$	(1,758	)	$	(3,805	)
State, net of federal	(200		)	(173		)
Foreign	(255		)	(332		)
Total deferred taxes	$	(2,213	)	$	(4,310	)

The following summarizes tax effects of temporary differences that give rise to significant portions of the deferred tax assets (liabilities) at December 31:

millions	2017			2016
Deferred tax liabilities
Oil and gas exploration and development operations	$	(2,599	)	$	(5,025	)
Midstream and other depreciable properties	(543		)	(870		)
Mineral operations	(312		)	(550		)
Other	(54		)	(147		)
Gross long-term deferred tax liabilities	(3,508		)	(6,592		)
Deferred tax assets
Oil and gas exploration and development costs	309			250
Foreign and state net operating loss carryforwards	562			648
U.S. foreign tax credit carryforwards	2,685			1,834
Compensation and benefit plans	365			672
Mark to market on derivatives	232			324
Other	166			309
Gross long-term deferred tax assets	4,319			4,037
Valuation allowances on deferred tax assets not expected to be realized	(3,024		)	(1,755		)
Net long-term deferred tax assets	1,295			2,282
Total deferred taxes	$	(2,213	)	$	(4,310	)

Valuation Allowances on Deferred Tax Assets Rollforward

The following summarizes changes in the balance of valuation allowances on deferred tax assets:

millions	2017			2016			2015
Balance at January 1	$	(1,755	)	$	(1,403	)	$	(864	)
Changes due to U.S. foreign tax credits	(1,287		)	(477		)	(384		)
Changes due to foreign and state net operating loss carryforwards	75			13			10
Changes due to foreign capitalized costs	(57		)	112			(165		)
Balance at December 31	$	(3,024	)	$	(1,755	)	$	(1,403	)

Schedule of Operating Loss Carryforwards

Tax carryforwards available for use on future income tax returns, prior to valuation allowance, at December 31, 2017, were as follows:

millions	Domestic		Foreign		Expiration
Net operating loss—foreign	$	—	$	1,184	2018 - Indefinite
Net operating loss—state	$	4,452	$	—	2018-2037

Schedule of Tax Credit Carryforwards

Tax carryforwards available for use on future income tax returns, prior to valuation allowance, at December 31, 2017, were as follows:

millions	Domestic		Foreign		Expiration
Foreign tax credits	$	2,685	$	—	2023-2028
Texas margins tax credit	$	30	$	—	2026

Taxes Receivable (Payable) Table

The following summarizes taxes receivable (payable) related to income tax expense (benefit) at December 31:

millions
Balance Sheet Classification	2017			2016
Income taxes receivable
Accounts receivable—other	$	53		$	180
Other assets	101			67
	154			247
Income taxes (payable)
Other current liabilities	(71		)	(6		)
Total net income taxes receivable (payable)	$	83		$	241

Unrecognized Tax Benefits Rollforward

Changes in the balance of unrecognized tax benefits, excluding interest and penalties on uncertain tax positions, were as follows:

	Assets (Liabilities)
millions	2017			2016			2015
Balance at January 1	$	(1,456	)	$	(1,780	)	$	(1,687	)
Increases related to prior-year tax positions	(15		)	(86		)	(99		)
Decreases related to prior-year tax positions	214			436			89
Increases related to current-year tax positions	(72		)	(26		)	(263		)
Settlements	12			—			180
Balance at December 31	$	(1,317	)	$	(1,456	)	$	(1,780	)

Tax Years Subject to Examination by Major Tax Jurisdiction Table

The following lists the tax years subject to examination by major tax jurisdiction:

	Tax Years
United States	2012-2017
Algeria	2014-2017
Ghana	2014-2017