Loans and ACL (Schedule of Retail Credit Exposure, Credit Risk Profile Based on Payment Activity) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Loans and leases	$ 118,689	$ 115,917
Direct Retail Lending, Excluding Covered [Member]
Loans and leases	8,042	15,869
Direct Retail Lending, Excluding Covered [Member] | Performing [Member]
Loans and leases	7,992	15,760
Direct Retail Lending, Excluding Covered [Member] | Nonperforming [Member]
Loans and leases	50	109
Retail Revolving Credit, Excluding Covered [Member]
Loans and leases	2,414	2,403
Retail Revolving Credit, Excluding Covered [Member] | Performing [Member]
Loans and leases	2,414	2,403
Retail Revolving Credit, Excluding Covered [Member] | Nonperforming [Member]
Loans and leases	0	0
Retail Residential Mortgage-Nonguaranteed, Excluding Covered [Member]
Loans and leases	31,813	24,648
Retail Residential Mortgage-Nonguaranteed, Excluding Covered [Member] | Performing [Member]
Loans and leases	31,515	24,405
Retail Residential Mortgage-Nonguaranteed, Excluding Covered [Member] | Nonperforming [Member]
Loans and leases	298	243
Retail Sales Finance, Excluding Covered [Member]
Loans and leases	10,269	9,382
Retail Sales Finance, Excluding Covered [Member] | Performing [Member]
Loans and leases	10,264	9,377
Retail Sales Finance, Excluding Covered [Member] | Nonperforming [Member]
Loans and leases	5	5
Retail Other Lending Subsidiaries, Excluding Covered [Member]
Loans and leases	6,020	5,960
Retail Other Lending Subsidiaries, Excluding Covered [Member] | Performing [Member]
Loans and leases	5,975	5,910
Retail Other Lending Subsidiaries, Excluding Covered [Member] | Nonperforming [Member]
Loans and leases	$ 45	$ 50