v3.19.3.a.u2
Related Party Transactions - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Related Party Transaction [Line Items]      
Due from related parties $ 119 $ 179  
Due to related parties 12 11  
BlackRock Mutual Funds and iShares ETFs [Member]      
Related Party Transaction [Line Items]      
Accounts receivable from related parties 995 878  
General and Administration Expense [Member]      
Related Party Transaction [Line Items]      
Expense with related parties $ 2 $ 2 $ 10
PNC [Member]      
Related Party Transaction [Line Items]      
Percentage of common stock of parent owned 22.00%    
Percentage of capital stock of parent owned 22.40%