Derivative Financial Instruments (Details 4) (Other income [Member], Interest rate contracts [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other income [Member] | Interest rate contracts [Member]
Gains and losses on derivative instruments designated and qualifying as hedging instruments in cash flow hedges
Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	$ (68)	$ (40)	$ (10)	$ (48)
Loss Reclassified from AOCI into Income (Effective Portion)	(4)	(2)	(8)	(5)
Loss Recognized in Income on the Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)