Allowance for Credit Losses Activity (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 497		$ 498		$ 571
Charge-offs	(10)		(25)		(19)
Recoveries	2		1		2
Net (charge-offs) recoveries	(8)		(24)		(17)
Provision	5		23
Ending balance	494		497		554
Allowance for loans losses	386		394		467
Allowance for unfunded commitments	108		103		87
Individually evaluated for impairment, loan balance	159		128		129
Individually evaluated for impairment, allowance for loan losses	38		32		22
Collectively evaluated for impairment, loan balance	42,869		43,851		39,883
Collectively evaluated for impairment, allowance for loan losses	348		362		445
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	91		98		93
Recoveries					1
Net (charge-offs) recoveries					1
Provision	6		(7)		6
Ending balance	97		91		100
Allowance for loans losses	36		33		49
Allowance for unfunded commitments	61		58		51
Individually evaluated for impairment, loan balance	66		26		30
Individually evaluated for impairment, allowance for loan losses	17		9		10
Collectively evaluated for impairment, loan balance	697		726		1,091
Collectively evaluated for impairment, allowance for loan losses	19		24		39
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	34		31		40
Charge-offs			(1)		(3)
Net (charge-offs) recoveries			(1)		(3)
Provision	(1)		4		(3)
Ending balance	33		34		34
Allowance for loans losses	22		24		24
Allowance for unfunded commitments	11		10		10
Individually evaluated for impairment, loan balance	38		38		36
Individually evaluated for impairment, allowance for loan losses	6		7		5
Collectively evaluated for impairment, loan balance	1,403		1,411		1,542
Collectively evaluated for impairment, allowance for loan losses	16		17		19
Financial Institutions
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	63		30		11
Charge-offs			(7)
Recoveries					1
Net (charge-offs) recoveries			(7)		1
Provision	(10)		40		5
Ending balance	53		63		17
Allowance for loans losses	30		41		3
Allowance for unfunded commitments	23		22		14
Individually evaluated for impairment, loan balance	14		24		4
Individually evaluated for impairment, allowance for loan losses	5		7
Collectively evaluated for impairment, loan balance	4,881		4,582		4,425
Collectively evaluated for impairment, allowance for loan losses	25		34		3
Lease Financings
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	66		91		90
Provision	(4)		(25)		3
Ending balance	62		66		93
Allowance for loans losses	62		66		93
Collectively evaluated for impairment, loan balance	1,518		1,558		1,579
Collectively evaluated for impairment, allowance for loan losses	62		66		93
Wealth Management Loans and Mortgages
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	29		31		41
Provision	5		(2)		(12)
Ending balance	34		29		29
Allowance for loans losses	29		23		23
Allowance for unfunded commitments	5		6		6
Individually evaluated for impairment, loan balance	31		30		52
Individually evaluated for impairment, allowance for loan losses	7		5		5
Collectively evaluated for impairment, loan balance	7,281		7,312		6,609
Collectively evaluated for impairment, allowance for loan losses	22		18		18
Other Residential Mortgages
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	156		162		235
Charge-offs	(10)		(15)		(16)
Recoveries	2		1
Net (charge-offs) recoveries	(8)		(14)		(16)
Provision	17		8		(6)
Ending balance	165		156		213
Allowance for loans losses	165		156		213
Collectively evaluated for impairment, loan balance	1,854		1,923		2,128
Collectively evaluated for impairment, allowance for loan losses	165		156		213
All Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance					1	[1]
Provision					1	[1]
Ending balance					2	[1]
Allowance for loans losses					2	[1]
Collectively evaluated for impairment, loan balance	15,964	[2]	16,341	[3]	13,202	[1]
Collectively evaluated for impairment, allowance for loan losses					2	[1]
Foreign
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	58		55		60
Charge-offs			(2)
Net (charge-offs) recoveries			(2)
Provision	(8)		5		6
Ending balance	50		58		66
Allowance for loans losses	42		51		60
Allowance for unfunded commitments	8		7		6
Individually evaluated for impairment, loan balance	10		10		7
Individually evaluated for impairment, allowance for loan losses	3		4		2
Collectively evaluated for impairment, loan balance	9,271		9,998		9,307
Collectively evaluated for impairment, allowance for loan losses	$ 39		$ 47		$ 58

[1] Includes $3,381 million of domestic overdrafts, $9,369 million of margin loans and $452 million of other loans at March 31, 2011.

[2] Includes $1,971 million of domestic overdrafts, $13,144 million of margin loans and $849 million of other loans at March 31, 2012.

[3] Includes $2,958 million of domestic overdrafts, $12,760 million of margin loans and $623 million of other loans at Dec. 31, 2011.