Allowance for Credit Losses (Schedule of Consumer Credit Exposure, Credit Risk Profile Based on Payment Activity) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Loans and leases	$ 114,140	$ 107,469
Direct Retail Lending [Member]
Loans and leases	15,710	14,506
Direct Retail Lending [Member] | Performing Financing Receivable [Member]
Loans and leases	15,576	14,364
Direct Retail Lending [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	134	142
Retail Revolving Credit [Member]
Loans and leases	2,291	2,212
Retail Revolving Credit [Member] | Performing Financing Receivable [Member]
Loans and leases	2,291	2,212
Retail Revolving Credit [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	0	0
Retail Residential Mortgage [Member]
Loans and leases	24,293	20,581
Retail Residential Mortgage [Member] | Performing Financing Receivable [Member]
Loans and leases	24,027	20,273
Retail Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	266	308
Retail Sales Finance [Member]
Loans and leases	7,723	7,401
Retail Sales Finance [Member] | Performing Financing Receivable [Member]
Loans and leases	7,716	7,394
Retail Sales Finance [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	7	7
Retail Other Lending Subsidiaries [Member]
Loans and leases	5,941	5,111
Retail Other Lending Subsidiaries [Member] | Performing Financing Receivable [Member]
Loans and leases	5,872	5,056
Retail Other Lending Subsidiaries [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	$ 69	$ 55