Allowance for Credit Losses (Schedule of Consumer Credit Exposure, Credit Risk Profile Based on Payment Activity) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Loans and leases	$ 108,161	$ 107,469
Direct Retail Lending [Member]
Loans and leases	14,862	14,467
Direct Retail Lending [Member] | Performing Financing Receivable [Member]
Loans and leases	14,723	14,325
Direct Retail Lending [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	139	142
Retail Revolving Credit [Member]
Loans and leases	2,159	2,212
Retail Revolving Credit [Member] | Performing Financing Receivable [Member]
Loans and leases	2,159	2,212
Retail Revolving Credit [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	0	0
Retail Residential Mortgage [Member]
Loans and leases	21,513	20,581
Retail Residential Mortgage [Member] | Performing Financing Receivable [Member]
Loans and leases	21,193	20,273
Retail Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	320	308
Retail Sales Finance [Member]
Loans and leases	7,587	7,401
Retail Sales Finance [Member] | Performing Financing Receivable [Member]
Loans and leases	7,572	7,394
Retail Sales Finance [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	15	7
Retail Other Lending Subsidiaries [Member]
Loans and leases	5,235	5,111
Retail Other Lending Subsidiaries [Member] | Performing Financing Receivable [Member]
Loans and leases	5,191	5,056
Retail Other Lending Subsidiaries [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	$ 44	$ 55