Loans and ACL (Summary of Loans Collectively Evaluated for Impairment) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Recorded Investment, Collectively evaluated for impairment	$ 117,040	$ 113,405
Related ALLL, Collectively evaluated for impairment	1,280	1,365
Commercial and Industrial, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	39,897	38,042
Related ALLL, Collectively evaluated for impairment	377	382
CRE Income Producing Properties, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	10,273	10,033
Related ALLL, Collectively evaluated for impairment	108	128
CRE Construction And Development, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	2,553	2,289
Related ALLL, Collectively evaluated for impairment	48	60
Commercial Other Lending Subsidiaries, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	4,725	4,501
Related ALLL, Collectively evaluated for impairment	16	15
Direct Retail Lending, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	7,693	15,648
Related ALLL, Collectively evaluated for impairment	99	166
Retail Revolving Credit, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	2,345	2,355
Related ALLL, Collectively evaluated for impairment	94	96
Retail Residential Mortgage-Nonguaranteed, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	30,652	22,557
Related ALLL, Collectively evaluated for impairment	211	160
Retail Residential Mortgage-Government Guaranteed, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	658	759
Related ALLL, Collectively evaluated for impairment	5	7
Retail Sales Finance, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	10,385	9,363
Related ALLL, Collectively evaluated for impairment	40	41
Retail Other Lending Subsidiaries, Excluding Covered [Member]
Recorded Investment, Collectively evaluated for impairment	6,206	5,823
Related ALLL, Collectively evaluated for impairment	191	196
Covered [Member]
Recorded Investment, Collectively evaluated for impairment	1,653	2,035
Related ALLL, Collectively evaluated for impairment	$ 91	$ 114