Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Tax carryforwards [Abstract]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 3,560
Assets
Other current assets	53	57
Other noncurrent assets	847	849
Liabilities
Other current liabilities	1	4
Noncurrent deferred tax liabilities	2,492	2,432
Net deferred tax liabilities	1,593	1,530
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	1,503
Foreign Country Kurdistan [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	128
CANADA
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	744
Foreign Tax Authority [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Charged to Cost and Expense	(61)	16	52
Internal Revenue Service (IRS) [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Charged to Cost and Expense	$ 930	$ 1,277	$ 585