Income Taxes (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Income Tax Disclosure [Line Items]
Unrecognized tax benefits	$ 6,221	$ 6,139
Portion that, if recognized, would reduce tax expense and effective tax rate	4,077	4,114
Accrued interest on unrecognized tax benefits	1,187	1,200
Accrued penalties on unrecognized tax benefits	127	109
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months lower limit	0	0
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months upper limit	1,800	1,600
Lower Limit [Member]
Income Tax Disclosure [Line Items]
Portion that, if recognized, would reduce tax expense and effective tax rate	0	0
Upper Limit [Member]
Income Tax Disclosure [Line Items]
Portion that, if recognized, would reduce tax expense and effective tax rate	$ 600	$ 650