Income Taxes (Details 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Qualified and Non-qualified Pension Benefits
Benefit Plan Information
Company contributions	$ 517	$ 556	$ 1,259
United States Qualified and Non-qualified Pension Benefits
Benefit Plan Information
Company contributions	237	290
Company contributions made in shares of common stock			600
International Qualified and Non-qualified Pension Benefits
Benefit Plan Information
Company contributions	280	266
Postretirement Benefits
Benefit Plan Information
Company contributions	$ 65	$ 62	$ 133