v3.19.3.a.u2
Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue (Collectively "Base Fees") by Type (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Disaggregation Of Revenue [Line Items]      
Total revenue $ 14,539 $ 14,198 $ 13,600
Investment Advisory, Administration Fees and Securities Lending Revenue [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 11,777 11,553 10,868
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity Active Product [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,554 1,654 1,654
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity iShares ETFs [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 3,495 3,549 3,220
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity Non-ETF Index [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 667 685 680
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 5,716 5,888 5,554
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income Active [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,918 1,840 1,717
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income iShares ETFs [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 963 825 808
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income Non-ETF Index [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 405 387 344
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 3,286 3,052 2,869
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Multi-asset [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,148 1,176 1,157
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,009 830 730
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member] | Illiquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 488 348 281
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member] | Liquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 413 384 358
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member] | Currency and Commodities [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 108 98 91
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Cash Management [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 618 607 558
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Long-term [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 11,159 10,946 10,310
Investment Advisory Performance Fees [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 450 412 594
Investment Advisory Performance Fees [Member] | Equity [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 36 91 152
Investment Advisory Performance Fees [Member] | Fixed Income [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 10 8 34
Investment Advisory Performance Fees [Member] | Multi-asset [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 19 19 33
Investment Advisory Performance Fees [Member] | Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 385 294 375
Investment Advisory Performance Fees [Member] | Alternatives [Member] | Illiquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 136 70 62
Investment Advisory Performance Fees [Member] | Alternatives [Member] | Liquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 249 224 313
Technology Services Revenue [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 974 785 657
Distribution Fees [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,069 1,155 1,183
Distribution Fees [Member] | Retrocessions [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 658 709 675
Distribution Fees [Member] | 12b-1 Fees (US Mutual Fund Distribution Fees) [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 358 406 466
Distribution Fees [Member] | Other Distribution Fees [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 53 40 42
Advisory and Other Revenue [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 269 293 298
Advisory and Other Revenue [Member] | Advisory [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 99 113 128
Advisory and Other Revenue [Member] | Other [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue $ 170 $ 180 $ 170