Derivatives and Hedging Activities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ 172	$ (102)
Other Expense [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	0	(1)
Other Expense [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	170	(102)
Other Income [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	1	0
Other Income [Member] | Equity-linked contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ 1	$ 1