Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Cash and investments segregated and on deposit for regulatory purposes, resale agreements	$ 17,899	$ 12,697
Securities held to maturity, fair value	$ 15,539	$ 17,848
Preferred stock, shares authorized	9,940,000	9,940,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, issued	0	0
Common stock, shares authorized	3,000,000,000	3,000,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares issued	1,487,543,446	1,428,604,522
Treasury stock, shares	216,378,623	226,222,313