Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Goodwill, Intersegment Transfers			$ 0
change in amount of loans serviced for third parties			(4.00%)
Mortgage servicing related income	70,000,000	72,000,000	151,000,000	144,000,000
Mortgage Servicing Rights
Mortgage servicing related income	80,000,000	94,000,000	163,000,000	186,000,000
Total unpaid principal amount of mortgaged loans serviced	153,400,000,000		153,400,000,000		157,800,000,000
Included in these amounts of loans serviced for third parties	118,900,000,000		118,900,000,000		124,100,000,000
Residential mortgage loans sold			1,400,000,000
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