Guarantee Arrangements and Pledged Assets and Collateral - Summary of Credit Ratings of Credit Risk Related Guarantees (Detail) (USD $) In Millions, unless otherwise specified				9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Sell Protection Credit Derivatives [Member]	Sep. 30, 2014 Single name credit default swap [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 Structured CDS [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 Index credit derivatives [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 Total return swaps [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 Standby Letters of Credit [Member]		Sep. 30, 2014 External Credit Rating, Investment Grade [Member]	Sep. 30, 2014 External Credit Rating, Investment Grade [Member] Sell Protection Credit Derivatives [Member]	Sep. 30, 2014 External Credit Rating, Investment Grade [Member] Single name credit default swap [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Investment Grade [Member] Structured CDS [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Investment Grade [Member] Index credit derivatives [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Investment Grade [Member] Total return swaps [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Investment Grade [Member] Standby Letters of Credit [Member]		Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member]	Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member] Sell Protection Credit Derivatives [Member]	Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member] Single name credit default swap [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member] Structured CDS [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member] Index credit derivatives [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member] Total return swaps [Member] Sell Protection Credit Derivatives [Member]		Sep. 30, 2014 External Credit Rating, Non Investment Grade [Member] Standby Letters of Credit [Member]
Credit Derivatives [Line Items]
Average Life in years				2 years 4 months 26 days	[1]	1 year 11 months 12 days	[1]	2 years 6 months 10 days	[1]	3 years 15 days	[1]	1 year 13 days	[2]
Credit Ratings of the Obligors or the Transactions	$ 182,070	$ 191,349	$ 171,067	$ 127,129	[1]	$ 17,197	[1]	$ 22,809	[1]	$ 3,932	[1]	$ 8,649	[2]		$ 139,717	$ 105,388	[1]	$ 14,811	[1]	$ 15,997	[1]	$ 3,521	[1]	$ 6,419	[2]		$ 31,350	$ 21,741	[1]	$ 2,386	[1]	$ 6,812	[1]	$ 411	[1]	$ 2,230	[2]
Credit Ratings of the Obligors or the Transactions, Total	$ 179,716													$ 146,136												$ 33,580

[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.