v3.19.2
Revenue - Schedule of Estimated Investment Advisory, Administration Fees Expected to be Recognized in Future, Related to Unsatisfied Portion of Performance Obligations (Detail) - Investment Advisory, Administration Fees and Securities Lending Revenue [Member] - USD ($)
$ in Millions
Jun. 30, 2019
Jun. 30, 2018
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation $ 280 $ 286
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-07-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period   6 months
Revenue, Remaining Performance Obligation   $ 43
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period   1 year
Revenue, Remaining Performance Obligation   $ 75
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-07-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 6 months  
Revenue, Remaining Performance Obligation $ 41  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 1 year 1 year
Revenue, Remaining Performance Obligation $ 74 $ 64
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 1 year 1 year
Revenue, Remaining Performance Obligation $ 62 $ 52
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 1 year
Revenue, Remaining Performance Obligation $ 53 $ 52
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01    
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period  
Revenue, Remaining Performance Obligation $ 50