Derivatives and Hedging Activities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ 140	$ (27)	$ 45	$ 33
Interest Expense [Member] | Foreign exchange contracts [Member] | Short-term Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	2	0	3
Interest Expense [Member] | Foreign exchange contracts [Member] | Long-term Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	31	0	61
Other Expense [Member] | Interest rate contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	0	(1)	2
Other Expense [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	139	(62)	44	(38)
Interest Income [Member] | Foreign exchange contracts [Member] | Investment Securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	3	0	5
Other Income [Member] | Equity-linked contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ 1	$ (1)	$ 2	$ 0