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The amount of the change in the period in the valuation allowance for foreign deferred tax assets.

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No definition available.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer.

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Amount after allocation of valuation allowances of noncurrent deferred tax asset attributable to deductible temporary differences and carryforwards. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

+ References

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign tax credit carryforwards.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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Amount of deferred tax liability attributable to taxable temporary differences, net of deferred tax asset attributable to deductible temporary differences and carryforwards net of valuation allowances expected to be realized or consumed within one year or operating cycle, if longer.

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Total of the adjustments in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability.

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Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, charged to costs and expenses.

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Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax carryforwards [Abstract]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 3,550
Operating Loss Carryforwards [Line Items]
Valuation Allowance Deferred Tax Asset Change In Amount Foreign	222
Assets
Other current assets	29us-gaap_DeferredTaxAssetsNetCurrent	53us-gaap_DeferredTaxAssetsNetCurrent
Other noncurrent assets	525us-gaap_DeferredTaxAssetsNetNoncurrent	847us-gaap_DeferredTaxAssetsNetNoncurrent
Liabilities
Other current liabilities	3us-gaap_DeferredTaxLiabilitiesCurrent	1us-gaap_DeferredTaxLiabilitiesCurrent
Noncurrent deferred tax liabilities	2,486	2,492
Net deferred tax liabilities	1,935us-gaap_DeferredTaxLiabilities	1,593us-gaap_DeferredTaxLiabilities
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	1,293
EQUATORIAL GUINEA
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	41
Foreign Country Kurdistan [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	180
CANADA
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	570
Foreign Tax Authority [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Charged to Cost and Expense			16
Valuation Allowances and Reserves, Adjustments	41	61
Internal Revenue Service (IRS) [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Charged to Cost and Expense		$ 930	$ 1,277