Summary of Subsequent Defaults (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended		6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended		6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014 Quarter to date		Jun. 30, 2013 Quarter to date		Jun. 30, 2014 Commercial Portfolio Segment Commercial and Industrial Loans		Jun. 30, 2013 Commercial Portfolio Segment Commercial and Industrial Loans		Jun. 30, 2014 Commercial Portfolio Segment Commercial and Industrial Loans Quarter to date		Jun. 30, 2013 Commercial Portfolio Segment Commercial and Industrial Loans Quarter to date		Jun. 30, 2014 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied		Jun. 30, 2013 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied		Jun. 30, 2013 Commercial Portfolio Segment Commercial Mortgage Loans, Owner Occupied Quarter to date		Jun. 30, 2014 Consumer Portfolio Segment Home Equity		Jun. 30, 2013 Consumer Portfolio Segment Home Equity		Jun. 30, 2014 Consumer Portfolio Segment Home Equity Quarter to date		Jun. 30, 2013 Consumer Portfolio Segment Home Equity Quarter to date		Jun. 30, 2014 Consumer Portfolio Segment Automobile Loans		Jun. 30, 2013 Consumer Portfolio Segment Automobile Loans		Jun. 30, 2014 Consumer Portfolio Segment Automobile Loans Quarter to date		Jun. 30, 2014 Consumer Portfolio Segment Credit Card		Jun. 30, 2013 Consumer Portfolio Segment Credit Card		Jun. 30, 2014 Consumer Portfolio Segment Credit Card Quarter to date		Jun. 30, 2013 Consumer Portfolio Segment Credit Card Quarter to date		Jun. 30, 2014 Residential Mortgage Loans		Jun. 30, 2013 Residential Mortgage Loans		Jun. 30, 2014 Residential Mortgage Loans Quarter to date		Jun. 30, 2013 Residential Mortgage Loans Quarter to date
Financing Receivable, Modifications
Number of contracts	986	[1]	1,195	[1]	418	[2]	491	[2]	9	[1]	2	[1]	3	[2]	1	[2]	2	[1]	4	[1]	4	[2]	20	[1]	34	[1]	10	[2]	20	[2]	4	[1]	3	[1]	2	[2]	870	[1]	926	[1]	363	[2]	411	[2]	81	[1]	226	[1]	40	[2]	55	[2]
Recorded Investment in Loans Modified in a TDR During the Period	$ 42	[1]	$ 46	[1]	$ 16	[2]	$ 12	[2]	$ 20	[1]			$ 6	[2]			$ 3	[1]	$ 1	[1]	$ 1	[2]	$ 1	[1]	$ 2	[1]	$ 1	[2]	$ 1	[2]							$ 6	[1]	$ 6	[1]	$ 3	[2]	$ 2	[2]	$ 12	[1]	$ 37	[1]	$ 6	[2]	$ 8	[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.