Guarantee Arrangements and Pledged Assets and Collateral - Summary of Credit Ratings of Credit Risk Related Guarantees (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	$ 172,635
Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	164,325
Single name CDS [Member]
Credit Derivatives [Line Items]
Average Life in years	2 years 4 months 24 days	[1]
Single name CDS [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	122,318	[1]
Structured CDS [Member]
Credit Derivatives [Line Items]
Average Life in years	1 year 8 months 12 days	[1]
Structured CDS [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	18,718	[1]
Index credit derivatives [Member]
Credit Derivatives [Line Items]
Average Life in years	3 years	[1]
Index credit derivatives [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	19,668	[1]
Total return swaps [Member]
Credit Derivatives [Line Items]
Average Life in years	3 years 10 months 12 days	[1]
Total return swaps [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	3,621	[1]
Standby Letters of Credit [Member]
Credit Derivatives [Line Items]
Average Life in years	1 year 1 month 6 days	[2]
Credit Ratings of the Obligors or the Transactions	8,310	[2]
External Credit Rating, Investment Grade [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	147,949
External Credit Rating, Investment Grade [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	141,499
External Credit Rating, Investment Grade [Member] | Single name CDS [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	102,297	[1]
External Credit Rating, Investment Grade [Member] | Structured CDS [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	16,548	[1]
External Credit Rating, Investment Grade [Member] | Index credit derivatives [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	19,465	[1]
External Credit Rating, Investment Grade [Member] | Total return swaps [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	3,189	[1]
External Credit Rating, Investment Grade [Member] | Standby Letters of Credit [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	6,450	[2]
External Credit Rating, Non Investment Grade [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	24,686
External Credit Rating, Non Investment Grade [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	22,826
External Credit Rating, Non Investment Grade [Member] | Single name CDS [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	20,021	[1]
External Credit Rating, Non Investment Grade [Member] | Structured CDS [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	2,170	[1]
External Credit Rating, Non Investment Grade [Member] | Index credit derivatives [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	203	[1]
External Credit Rating, Non Investment Grade [Member] | Total return swaps [Member] | Sell-protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	432	[1]
External Credit Rating, Non Investment Grade [Member] | Standby Letters of Credit [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	$ 1,860	[2]

[1] The credit ratings in the table represent external credit ratings for classification as investment grade and non-investment grade.

[2] External ratings for most of the obligors are not available. Presented above are the internal credit ratings which are developed using similar methodologies and rating scale equivalent to external credit ratings for purposes of classification as investment grade and non-investment grade.