Allowance for Credit Losses (Schedule of Consumer Credit Exposure, Credit Risk Profile Based on Payment Activity) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Loans and leases	$ 111,075	$ 107,469
Direct Retail Lending [Member]
Loans and leases	15,155	14,467
Direct Retail Lending [Member] | Performing Financing Receivable [Member]
Loans and leases	15,022	14,325
Direct Retail Lending [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	133	142
Retail Revolving Credit [Member]
Loans and leases	2,206	2,212
Retail Revolving Credit [Member] | Performing Financing Receivable [Member]
Loans and leases	2,206	2,212
Retail Revolving Credit [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	0	0
Retail Residential Mortgage [Member]
Loans and leases	23,117	20,581
Retail Residential Mortgage [Member] | Performing Financing Receivable [Member]
Loans and leases	22,854	20,273
Retail Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	263	308
Retail Sales Finance [Member]
Loans and leases	7,794	7,401
Retail Sales Finance [Member] | Performing Financing Receivable [Member]
Loans and leases	7,781	7,394
Retail Sales Finance [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	13	7
Retail Other Lending Subsidiaries [Member]
Loans and leases	5,684	5,111
Retail Other Lending Subsidiaries [Member] | Performing Financing Receivable [Member]
Loans and leases	5,615	5,056
Retail Other Lending Subsidiaries [Member] | Nonperforming Financing Receivable [Member]
Loans and leases	$ 69	$ 55