Guarantee Arrangements and Pledged Assets and Collateral - Summary of Credit Ratings of Credit Risk Related Guarantees (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	$ 128,894		$ 191,349
Credit Ratings of the Obligors or the Transactions, Total	126,209
Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	117,768
Single name credit default swap [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Average Life in years	2 years 7 months 22 days	[1]
Credit Ratings of the Obligors or the Transactions	92,654	[1]
Structured CDS [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Average Life in years	1 year 11 months 24 days	[1]
Credit Ratings of the Obligors or the Transactions	7,027	[1]
Index credit derivatives [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Average Life in years	2 years 5 months 13 days	[1]
Credit Ratings of the Obligors or the Transactions	14,258	[1]
Total return swaps [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Average Life in years	2 years 10 months 3 days	[1]
Credit Ratings of the Obligors or the Transactions	3,829	[1]
Standby Letters of Credit [Member]
Credit Derivatives [Line Items]
Average Life in years	1 year 1 month 25 days	[2]
Credit Ratings of the Obligors or the Transactions	8,441	[2]
External Credit Rating, Investment Grade [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions, Total	100,508
External Credit Rating, Investment Grade [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	94,203
External Credit Rating, Investment Grade [Member] | Single name credit default swap [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	78,019	[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	6,340	[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	6,422	[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	3,422	[1]
External Credit Rating, Investment Grade [Member] | Standby Letters of Credit [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	6,305	[2]
External Credit Rating, Non Investment Grade [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions, Total	25,701
External Credit Rating, Non Investment Grade [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	23,565
External Credit Rating, Non Investment Grade [Member] | Single name credit default swap [Member] | Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Ratings of the Obligors or the Transactions	14,635	[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	687	[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	7,836	[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	407	[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	$ 2,136	[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.