Capital Stock (Details) (USD $) In Millions, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Basic:
Income attributable to common stock	$ 1,240	$ 860	$ 2,355	$ 1,565
Income attributable to common stock, shares	384	338	383	337
Income attributable to common stock, per share	$ 3.23	$ 2.55	$ 6.14	$ 4.64
Effect of Dilutive Securities:
Mandatory Convertible Preferred Stock	12		12
Mandatory Convertible Preferred Stock, Income	19		38
Stock options and other	1	1	2	2
Diluted:
Income attributable to common stock, including assumed conversions, Amount	$ 1,259	$ 860	$ 2,393	$ 1,565
Income attributable to common stock, including assumed conversions, Shares	397	339	397	339
Income attributable to common stock, including assumed conversions, per share	$ 3.17	$ 2.53	$ 6.03	$ 4.61