Trading Assets and Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Fair value of derivatives reduced by cash collateral received	$ 9,054	[1]	$ 11,359	[1]
Increase decrease in fair value of derivative included in trading liabilities	8,689	[1]	10,315	[1]
Trading Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of derivatives reduced by cash collateral received	5,300		5,100
Trading Liabilities [Member]
Schedule of Available-for-sale Securities [Line Items]
Increase decrease in fair value of derivative included in trading liabilities	$ 1,400		$ 1,300

[1] The gross amounts of recognized assets includes $86.2 billion of trading related derivatives which are included in trading assets in our consolidated balance sheet and $1.6 billion of derivatives designated in hedging activities that are included in other assets in our consolidated balance sheet at March 31, 2013.The gross amounts of recognized assets includes $93.9 billion of trading related derivatives which are included in trading assets in our consolidated balance sheet and $1.5 billion of derivatives designated in hedging activities that are included in other assets in our consolidated balance sheet at December 31, 2012.