Loans and Commitments to Extend Credit (Net Unfunded Credit Commitments) (Details) (Commitments to Extend Credit [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	$ 124,142	$ 120,592
Commercial And Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	82,790	78,703
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	19,325	19,814
Credit Card [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	17,101	17,381
Other Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	$ 4,926	$ 4,694