Income Taxes (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Additional Income Taxes (Textual)
Gross deferred assets before application of valuation allowance	$ 1,204,000,000
Income Taxes (Textual) [Abstract]
Alternative minimum tax credit carryforwards	140,000,000
other business credit carryforwards	1,000,000
Foreign tax credit carryforwards	255,000,000
Unrecognized tax benefits that would impact effective income tax rate	331,000,000
Number of months impacting effective income tax rate if unrecognized tax benefits are recognized	12 months
The low end of the range of potential unrecognized tax benefits reasonably possible to be reduced by settlements or lapses of statutes of limitation	30,000,000
The High end of the range of potential unrecognized tax benefits reasonably possible to be reduced by settlements or lapses of statutes of limitation	40,000,000
Old supplementary tax rate on petroleum operations (in percentage)	20.00%
New supplementary tax rate on petroleum operations (in percentage)	32.00%
Undistributed earnings from foreign subsidiaries expected to be indefinitely reinvested in foreign operations	5,200,000,000
Approximate amount of deferred tax liability that would be recognized if foreign operations earnings are not indefinitely reinvested	1,800,000,000
Income tax paid ( net of refunds)	1,384,000,000	1,450,000,000	1,177,000,000
Approximate accrued interest and penalties	42,000,000	16,000,000
Year in which foreign tax credit carryforwards begin to expire	2016
United States federal [Member]
Additional Income Taxes (Textual)
Gross deferred assets before application of valuation allowance	90,000,000
Year in which operating losses begin to expire	2020
Foreign Jurisdictions [Member]
Additional Income Taxes (Textual)
Gross deferred assets before application of valuation allowance	920,000,000
Year in which operating losses begin to expire	2020
Various States [Member]
Additional Income Taxes (Textual)
Gross deferred assets before application of valuation allowance	$ 194,000,000
Year in which operating losses begin to expire	2012