Loans and Commitments to Extend Credit (Net Unfunded Credit Commitments) (Details) (Commitments to Extend Credit [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	$ 118,285	[1]	$ 103,271	[1]
Commercial And Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	75,790		64,955
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	20,075		18,317
Credit Card [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	17,692		16,216
Other Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Net Unfunded Credit Commitments	$ 4,728		$ 3,783

[1] Excludes standby letters of credit. See Note 18 Commitments and Guarantees for additional information on standby letters of credit.