Fair Value Disclosure (Details) (Fair Value Measurements valued on recurring basis, USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Level 2 Input | Carrying Amount
Fair value disclosure
Long-term debt, excluding capital lease obligations	$ 21,029	$ 7,328
Level 2 Input | Fair Value
Fair value disclosure
Long-term debt, excluding capital lease obligations	21,516	8,007
Level 3 Input | Carrying Amount
Fair value disclosure
Assets-Investment securities	78
Level 3 Input | Fair Value
Fair value disclosure
Assets-Investment securities	$ 78