v3.8.0.1
Significant Accounting Policies - Additional Information (Detail) - USD ($)
$ in Millions
Mar. 31, 2018
Jan. 01, 2018
Dec. 31, 2017
Significant Accounting Policies [Line Items]      
Other assets $ 2,157   $ 1,636
Other liabilities 2,130   1,626
Fair value of loaned securities 24,800   22,300
Fair value of collateral held for loan securities $ 27,247   24,190
Minimum [Member]      
Significant Accounting Policies [Line Items]      
Collateral cash and securities received in exchange of value of securities lent in order to reduce counterparty risk 102.00%    
Maximum [Member]      
Significant Accounting Policies [Line Items]      
Collateral cash and securities received in exchange of value of securities lent in order to reduce counterparty risk 112.00%    
Consolidated VIEs [Member]      
Significant Accounting Policies [Line Items]      
Deferred carried interest, contract liability $ 224   $ 219
Accounting Standards Update 2014-09 [Member] | Adoption of the New Revenue Standard Adjustment [Member]      
Significant Accounting Policies [Line Items]      
Other assets   $ 19  
Other liabilities   25  
Net decrease in retained earnings   $ 6