Credit Quality and the Allowance for Loan and Lease Losses - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Financing Receivable, Impaired [Line Items]
Larger commercial loans, subject to impairment review	$ 3,013	[1]	$ 2,931	[2]
Interest income recognized on impaired loans	83		74		54
Average impaired loans	$ 2,968		$ 3,200		$ 2,900

[1] Includes $390, $1,117 and $495, respectively, of commercial, residential mortgage and consumer TDRs on accrual status; $160, $141 and $79, respectively, of commercial, residential mortgage and consumer TDRs on nonaccrual status.

[2] Includes $228, $1,066 and $492, respectively, of commercial, residential mortgage and consumer TDRs on accrual status; $141, $116 and $90, respectively, of commercial, residential mortgage and consumer TDRs on nonaccrual status.