Summary of Loans Modified in a TDR (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 number
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	16,912
Recorded Investment in Loans Modified in a TDR During the Period	$ 810
Increase (Decrease) to ALLL Upon Modification	9
Charge-offs Recognized Upon Modification	9
Commercial Portfolio Segment | CommercialAndIndustrialLoansMember [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	52
Recorded Investment in Loans Modified in a TDR During the Period	83
Increase (Decrease) to ALLL Upon Modification	(4)
Charge-offs Recognized Upon Modification	3
Commercial Portfolio Segment | Commercial Mortgage Loans Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	32
Recorded Investment in Loans Modified in a TDR During the Period	55
Increase (Decrease) to ALLL Upon Modification	(6)
Charge-offs Recognized Upon Modification	2
Commercial Portfolio Segment | Commercial Mortgage Loans Non Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	39
Recorded Investment in Loans Modified in a TDR During the Period	90
Increase (Decrease) to ALLL Upon Modification	(21)
Charge-offs Recognized Upon Modification	3
Commercial Portfolio Segment | Commercial Construction
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	26
Recorded Investment in Loans Modified in a TDR During the Period	59
Increase (Decrease) to ALLL Upon Modification	(9)
Charge-offs Recognized Upon Modification	1
Commercial Portfolio Segment | Commercial Leases [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	2
Consumer Portfolio Segment | Home Equity
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	1,317
Recorded Investment in Loans Modified in a TDR During the Period	80
Increase (Decrease) to ALLL Upon Modification	1
Consumer Portfolio Segment | Automobile Loans
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	1,482
Recorded Investment in Loans Modified in a TDR During the Period	26
Increase (Decrease) to ALLL Upon Modification	3
Consumer Portfolio Segment | Credit Card
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	12,234
Recorded Investment in Loans Modified in a TDR During the Period	79
Increase (Decrease) to ALLL Upon Modification	11
Residential Mortgage Loans
Financing Receivable, Modifications [Line Items]
Number of Loans Modified in a TDR During the Period	1,728
Recorded Investment in Loans Modified in a TDR During the Period	338
Increase (Decrease) to ALLL Upon Modification	$ 34