Derivatives and Hedging Activities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ (88)	$ 140	$ 82	$ 45
Other Expense [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	1	0	0	(1)
Other Expense [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	(90)	139	80	44
Other Income [Member] | Equity-linked contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gains (losses)	$ 1	$ 1	$ 2	$ 2