Loans - Purchased Credit-Impaired Accretable Yields (Details) (Consumer, excluding credit card, Purchased Credit-Impaired, USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Consumer, excluding credit card | Purchased Credit-Impaired
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Beginning Balance	$ 18,606	$ 19,567	$ 18,457	$ 19,072
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion	(535)	(606)	(1,673)	(1,902)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Changes in Interest Rates on Variable Rate Loans	(102)	(91)	(212)	(264)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications to Nonaccretable Difference	(259)	28	1,138	1,992
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Ending Balance	$ 17,710	$ 18,898	$ 17,710	$ 18,898
Accretable Yield Percentage	4.24%	4.30%	4.32%	4.41%