Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended							12 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2009 Charges Relating To Cost Reduction Measures	Dec. 31, 2011 Margin requirements	Dec. 31, 2011 Collateral Requirements	Aug. 28, 2008 Total Bond Market Fund Litigation	Dec. 31, 2011 optionsXpress Merger Litigation LegalMatter	Jul. 29, 2011 optionsXpress Merger Litigation Maximum	Dec. 31, 2011 optionsXpress Merger Litigation Circuit Court of Cook County, Illinois LegalMatter	Dec. 31, 2011 optionsXpress Merger Litigation Court of Chancery of the State of Delaware LegalMatter	Dec. 31, 2010 YieldPlus Fund Litigation
Commitments and Contingencies Disclosure [Line Items]
Rent expense	$ 187,000,000	$ 168,000,000	$ 213,000,000	$ 37,000,000
Aggregate face amount of letter of credit agreements					350,000,000	78,000,000
Alleged minimum percentage of fund assets invested in CMOs and mortgage-backed securities without obtaining shareholder vote							25.00%
Number of class action lawsuits filed Between March 21, 2011 and April 6, 2011								10		7	3
Number of consolidated amended complaints										1	1
Fee application by plaintiff's counsel									650,000
Class action litigation charges	(7,000,000)	(320,000,000)										199,000,000
Insurance Proceeds												$ 39,000,000