Fair Value Measurements (Details 4) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Fair Value Measurements (Textuals) [Abstract]
Approximate amount of level 3 liability transfers from unsecured short-term borrowings to unsecured long-term borrowings			$ 230
Cash Instruments [Member]
Fair Value Measurements (Textuals) [Abstract]
Net Unrealized Gains / (Losses) Relating to Instruments Still Held at the Reporting Date	651	82	1,846	795
Derivatives Net [Member]
Fair Value Measurements (Textuals) [Abstract]
Net Unrealized Gains / (Losses) Relating to Instruments Still Held at the Reporting Date	$ 456	$ 1,386	$ 93	$ 2,852