XML 59 R44.htm IDEA: XBRL DOCUMENT v3.8.0.1
Financial Assets And Financial Liabilities (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Transfers of financial instruments owned from level 1 to level 3 $ 1  
Securities purchased under agreement to resell segregated for regulatory purposes 9,200 $ 11,000
Fair Value Assets Level 2 To Level 3 Amount   1
Total financial instruments owned, at fair value 3,154 4,037
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 4 $ 1
Level 3 | Convertible Debt Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value $ 2