Loans and ACL (Schedule of Consumer Credit Exposure, Credit Risk Profile Based on Payment Activity) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Loans and leases	$ 115,794	$ 114,603
Direct Retail Lending [Member]
Loans and leases	16,069	15,817
Direct Retail Lending [Member] | Performing Financing Receivable [Member]
Loans and leases	15,950	15,685
Direct Retail Lending [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	119	132
Retail Revolving Credit [Member]
Loans and leases	2,325	2,330
Retail Revolving Credit [Member] | Performing Financing Receivable [Member]
Loans and leases	2,325	2,330
Retail Revolving Credit [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	0	0
Retail Residential Mortgage [Member]
Loans and leases	23,795	24,272
Retail Residential Mortgage [Member] | Performing Financing Receivable [Member]
Loans and leases	23,541	24,003
Retail Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	254	269
Retail Sales Finance [Member]
Loans and leases	8,821	7,736
Retail Sales Finance [Member] | Performing Financing Receivable [Member]
Loans and leases	8,816	7,729
Retail Sales Finance [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	5	7
Retail Other Lending Subsidiaries [Member]
Loans and leases	6,445	5,999
Retail Other Lending Subsidiaries [Member] | Performing Financing Receivable [Member]
Loans and leases	6,379	5,916
Retail Other Lending Subsidiaries [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	$ 66	$ 83