v2.4.0.8
Significant Accounting Policies (Details) (USD $)
6 Months Ended
Jun. 30, 2014
Dec. 31, 2013
May 03, 2007
Significant Accounting Policies [Abstract]      
SIP expense - Year of grant     50.00%
SIP expense - Remaining vesting period     50.00%
SIP expense - Employees over 59 in year of grant     100.00%
Percent of shares forfeited post employment     50.00%
Over 59 percent of shares eligible     100.00%
U.S. Treasury Bills $ 3,430,000,000 $ 1,300,000,000  
Securities Purchased Under Agreement to Resell Segregated for Regulatory Purposes 5,910,000,000 6,730,000,000  
Equity method investments 24,700,000 27,500,000  
Cost method investments $ 27,500,000 $ 27,600,000  
Property and equipment useful lives Computer equipment is depreciated over three to five years and office furniture and equipment are depreciated over five to seven years. Qualifying costs for internally developed software are capitalized and amortized over the expected useful life of the developed software, not to exceed three years.