Securitizations and Variable Interest Entities, Principal Balances of Off-Balance Sheet Securitized Loans (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	$ 1,381,918		$ 1,437,817
Delinquent loans and foreclosed assets	32,184		36,663
Net charge-offs	624	$ 1,423
Total Commercial [Member]
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	109,856		114,081
Delinquent loans and foreclosed assets	7,204		7,949
Net charge-offs	196	706
Real estate mortgage [Member]
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	109,856		114,081
Delinquent loans and foreclosed assets	7,204		7,949
Net charge-offs	196	706
Total Consumer [Member]
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	1,272,062		1,323,736
Delinquent loans and foreclosed assets	24,980		28,714
Net charge-offs	428	717
Real estate 1-4 family first mortgage [Member]
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	1,270,556		1,322,136
Delinquent loans and foreclosed assets	24,912		28,639
Net charge-offs	428	717
Real estate 1-4 family junior lien mortgage [Member]
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	1		1
Delinquent loans and foreclosed assets	0		0
Net charge-offs	0	0
Other revolving credit and installment [Member]
Principal Balances - Off-Balance Sheet Securitized Loans [Abstract]
Total loans	1,505		1,599
Delinquent loans and foreclosed assets	68		$ 75
Net charge-offs	$ 0	$ 0