Summary of Subsequent Defaults (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended				3 Months Ended				9 Months Ended		3 Months Ended		9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014 Quarter to date		Sep. 30, 2013 Quarter to date		Sep. 30, 2014 Commercial Portfolio Segment Commercial and Industrial Loans		Sep. 30, 2013 Commercial Portfolio Segment Commercial and Industrial Loans		Sep. 30, 2013 Commercial Portfolio Segment Commercial and Industrial Loans Quarter to date		Sep. 30, 2014 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied		Sep. 30, 2013 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied		Sep. 30, 2014 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied Quarter to date		Sep. 30, 2013 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied Quarter to date		Sep. 30, 2014 Commercial Portfolio Segment Commercial Mortgage Loans, Non Owner Occupied		Sep. 30, 2014 Commercial Portfolio Segment Commercial Mortgage Loans, Non Owner Occupied Quarter to date		Sep. 30, 2014 Consumer Portfolio Segment Home Equity		Sep. 30, 2013 Consumer Portfolio Segment Home Equity		Sep. 30, 2014 Consumer Portfolio Segment Home Equity Quarter to date		Sep. 30, 2013 Consumer Portfolio Segment Home Equity Quarter to date		Sep. 30, 2014 Consumer Portfolio Segment Automobile Loans		Sep. 30, 2013 Consumer Portfolio Segment Automobile Loans		Sep. 30, 2014 Consumer Portfolio Segment Automobile Loans Quarter to date		Sep. 30, 2014 Consumer Portfolio Segment Credit Card		Sep. 30, 2013 Consumer Portfolio Segment Credit Card		Sep. 30, 2014 Consumer Portfolio Segment Credit Card Quarter to date		Sep. 30, 2013 Consumer Portfolio Segment Credit Card Quarter to date		Sep. 30, 2014 Residential Mortgage Loans		Sep. 30, 2013 Residential Mortgage Loans		Sep. 30, 2014 Residential Mortgage Loans Quarter to date		Sep. 30, 2013 Residential Mortgage Loans Quarter to date
Financing Receivable, Modifications [Line Items]
Number of contracts	1,480	[1]	1,677	[1]	494	[2]	482	[2]	9	[1]	3	[1]	1	[2]	3	[1]	6	[1]	1	[2]	2	[2]	2	[1]	2	[2]	24	[1]	55	[1]	4	[2]	21	[2]	6	[1]	3	[1]	2	[2]	1,255	[1]	1,306	[1]	385	[2]	380	[2]	181	[1]	304	[1]	100	[2]	78	[2]
Recorded Investment in Loans Modified in a TDR During the Period	$ 58	[1]	$ 65	[1]	$ 16	[2]	$ 19	[2]	$ 20	[1]	$ 6	[1]	$ 5	[2]	$ 4	[1]	$ 1	[1]	$ 1	[2]			$ 1	[1]	$ 1	[2]	$ 1	[1]	$ 3	[1]			$ 1	[2]							$ 8	[1]	$ 8	[1]	$ 2	[2]	$ 2	[2]	$ 24	[1]	$ 47	[1]	$ 12	[2]	$ 11	[2]

[1] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality.

[2]  Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality.