Credit Quality and the Allowance for Loan and Lease Losses - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Financing Receivable, Impaired [Line Items]
Larger commercial loans, subject to impairment review	$ 2,985	[1]	$ 2,957	[2]	$ 3,013	[3]
Interest income recognized on impaired loans	24		48
Average impaired loans	$ 2,993		$ 2,959

[1] Includes $481, $1,125 and $499, respectively, of commercial, residential mortgage and consumer TDRs on accrual status; $157, $130 and $71, respectively, of commercial, residential mortgage and consumer TDRs on nonaccrual status.

[2] Includes $243, $1,083, and $515, respectively, of commercial, residential mortgage and consumer TDRs on accrual status; $149, $121 and $148, respectively, of commercial, residential mortgage and consumer TDRs on nonaccrual status.

[3] 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.