Derivatives and Hedging Activities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ (14)	$ (14)	$ 31	$ 8
Interest Expense [Member] | Foreign exchange contracts [Member] | Short-term Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	0	0	3
Interest Expense [Member] | Foreign exchange contracts [Member] | Long-term Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	33	0	94
Other Expense [Member] | Interest rate contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	(1)	0	(2)	2
Other Expense [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	(13)	(48)	31	(97)
Interest Income [Member] | Foreign exchange contracts [Member] | Securities Investment [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	2	0	7
Other Income [Member] | Equity-linked contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ 0	$ (1)	$ 2	$ (1)