Income Taxes Uncertain Tax Positions (Details) (USD $)	1 Months Ended	12 Months Ended			1 Months Ended				3 Months Ended
	Jan. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2011 Brazil [Member]	Dec. 31, 2012 Brazil [Member]	Dec. 31, 2012 Mexico 2004 [Member]	Dec. 31, 2012 Mexico [Member]	Dec. 31, 2010 Canada [Member]
Income Tax Examination [Line Items]
Unrecognized Tax Benefit that Would Favorably Affect Effective Tax Rate in Future		$ 1,210,000,000	$ 326,000,000
Liability for Uncertain Tax Positions Netted Against Deferred Tax Assets in Same Jurisdiction		1,550,000,000	1,285,000,000
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits - Beginning Balance	2,745,000,000	2,370,000,000	5,169,000,000	5,410,000,000
Additions to Current Year Tax Positions		112,000,000	129,000,000	195,000,000
Additions to Prior Year Tax Positions		512,000,000	562,000,000	803,000,000
Reductions to Prior Year Tax Positions		(141,000,000)	(1,002,000,000)	(475,000,000)
Reductions in Tax Positions due to Lapse of Statutory Limitations		(34,000,000)	(64,000,000)	(18,000,000)
Settlements		(112,000,000)	(2,399,000,000)	(761,000,000)
Other		38,000,000	(25,000,000)	15,000,000
Unrecognized Tax Benefits - Ending Balance		2,745,000,000	2,370,000,000	5,169,000,000
Interest Income		12,000,000	7,000,000	13,000,000
Interest Expense (Benefit)		52,000,000	(113,000,000)	20,000,000
Penalties		4,000,000	(25,000,000)	1,000,000
Accrued Interest Payable		117,000,000	103,000,000
Accrued Penalties		105,000,000	89,000,000
Tax Benefit from Prior Year Research Credits	160,000,000
Foreign Tax Assessment						181,000,000	136,000,000	309,000,000
Resolution Of Uncertain Tax Positions In Full Valuation Allowance Jurisdictions			2,700,000,000
Brazilian Income Tax Settlement					241,000,000
Canadian Tax Resolution									$ 140,000,000