Derivative Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Derivative Instruments and Hedging Activities Disclosure [Line Items]
This amount represents additional cash collateral received from derivative counterparties not offset against derivative assets and liabilities	$ 36,700,000		$ 36,700,000		$ 9,900,000
This amount represents additional cash collateral deposited with derivative counterparties not offset against derivative assets and liabilities	49,000,000		49,000,000		500,000
Aggregate fair value of all derivative instruments with credit-risk-related contingent features that are in a liability position	2,100,000,000		2,100,000,000		3,300,000,000
Collateral deposited with derivative counterparties for derivatives instruments with credit-risk-related contigent features that are in a liability position	1,600,000,000		1,600,000,000		2,900,000,000
Termination payments that could have been required for derivative instruments with credit-risk-related contingent features	673,800,000		673,800,000		387,100,000
Sterling denominated debt designated as hedges of foreign exchange risk	243,100,000		243,100,000		241,800,000
Maximum length of time being hedged for exposure to variability in future cash flows of forecasted foreign currency denominated transactions			Twenty-three months is the maximum length of time over which the exposure to variability in future cash flows of forecasted foreign currency denominated transactions is being hedged.
Estimated net gain (loss) to be reclassified into earnings within the next twelve months relating to cash flow hedges			8,900,000
Derivative Financial Instruments, Assets
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative assets recorded on the consolidated balance sheet, reduced as a result of master netting agreements	1,400,000,000		1,400,000,000		1,800,000,000
Reduction in derivative assets (liabilities) due to cash collateral received from (deposited with) derivative counterparties	1,300,000,000		1,300,000,000		3,000,000,000
Derivative Financial Instruments, Liabilities
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative liabilities recorded on the consolidated balance sheet, reduced as a result of master netting agreements	1,400,000,000		1,400,000,000		1,800,000,000
Reduction in derivative assets (liabilities) due to cash collateral received from (deposited with) derivative counterparties	(1,600,000,000)		(1,600,000,000)		(2,300,000,000)
Client Related and Trading
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Percentage of derivatives outstanding related to client-related and trading activities	97.00%		97.00%		97.00%
Changes recorded in the fair value of the hedged items in a fair value hedge	0	0	300,000	0
The net gain/loss recognized in earnings during the period representing the amount of hedge ineffectiveness for fair value hedges of available for sale investment securities, senior notes, or subordinated debt	$ 0	$ 0	$ 300,000	$ 0