Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Goodwill, Intersegment Transfers	$ 0
change in amount of loans serviced for third parties	(2.00%)
Mortgage servicing related income	81,000,000	72,000,000
Mortgage Servicing Rights
Mortgage servicing related income	84,000,000	92,000,000
Total unpaid principal amount of mortgaged loans serviced	155,400,000,000		157,800,000,000
Included in these amounts of loans serviced for third parties	121,400,000,000		124,100,000,000
Residential mortgage loans sold	600,000,000
Retail Banking [Member]
Goodwill, Intersegment Transfers	(4,854,000,000)
Retail Banking [Member] | Consumer Banking and Private Wealth Management Segment [Member]
Goodwill, Intersegment Transfers	3,596,000,000
Retail Banking [Member] | Wholesale Banking [Member]
Goodwill, Intersegment Transfers	1,259,000,000
Wealth and Investment Management Segment [Member]
Goodwill, Intersegment Transfers	(382,000,000)
Wealth and Investment Management Segment [Member] | Consumer Banking and Private Wealth Management Segment [Member]
Goodwill, Intersegment Transfers	335,000,000
Diversified Commercial Banking Reporting Unit [Member] | Wholesale Banking [Member]
Goodwill, Intersegment Transfers	928,000,000
Corporate and Investment Banking Segment [Member]
Goodwill, Intersegment Transfers	(180,000,000)
Corporate and Investment Banking Segment [Member] | Wholesale Banking [Member]
Goodwill, Intersegment Transfers	180,000,000
Wealth and Investment Management [Member] | Wholesale Banking [Member]
Goodwill, Intersegment Transfers	$ 47,000,000