Derivative Instruments and Hedging Activities (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Offsetting Assets [Abstract]
Derivative Assets, Gross Amount Recognized	$ 1,045	$ 749
Derivative Assets, Gross Amounts Offset	963	663
Derivative Assets, Net Amounts Presented	82	86
Derivative Assets, Gross Amounts Not Offset	46	64
Derivative Assets, Net Amount	36	22
Offsetting Liabilities [Abstract]
Derivative Liabilities, Gross Amount Recognized	1,049	812
Derivative Liabilities, Gross Amounts Offset	963	663
Derivative Liabilities	86	149
Derivative Liabilities, Gross Amount Not Offset	1	5
Derivative Liabilities, Net Amount	$ 85	$ 144