v3.20.4
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, 2020
Dec. 31, 2019
Dec. 31, 2018
Disaggregation Of Revenue [Line Items]      
Total revenue $ 16,205 $ 14,539 $ 14,198
Investment Advisory, Administration Fees and Securities Lending Revenue [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 12,639 11,777 11,553
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity Active Product [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,737 1,554 1,654
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity iShares ETFs [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 3,499 3,495 3,549
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity Non-ETF Index [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 664 667 685
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Equity [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 5,900 5,716 5,888
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income Active [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,957 1,918 1,840
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income iShares ETFs [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,119 963 825
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income Non-ETF Index [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 463 405 387
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Fixed Income [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 3,539 3,286 3,052
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Multi-asset [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,163 1,148 1,176
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,247 1,009 830
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member] | Illiquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 577 488 348
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member] | Liquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 502 413 384
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Alternatives [Member] | Currency and Commodities [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 168 108 98
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Cash Management [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 790 618 607
Investment Advisory, Administration Fees and Securities Lending Revenue [Member] | Long-term [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 11,849 11,159 10,946
Investment Advisory Performance Fees [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,104 450 412
Investment Advisory Performance Fees [Member] | Equity [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 91 36 91
Investment Advisory Performance Fees [Member] | Fixed Income [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 35 10 8
Investment Advisory Performance Fees [Member] | Multi-asset [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 35 19 19
Investment Advisory Performance Fees [Member] | Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 943 385 294
Investment Advisory Performance Fees [Member] | Alternatives [Member] | Illiquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 83 136 70
Investment Advisory Performance Fees [Member] | Alternatives [Member] | Liquid Alternatives [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 860 249 224
Technology Services Revenue [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,139 974 785
Distribution Fees [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 1,131 1,069 1,155
Distribution Fees [Member] | Retrocessions [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 736 658 709
Distribution Fees [Member] | 12b-1 Fees (US Mutual Fund Distribution Fees) [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 337 358 406
Distribution Fees [Member] | Other Distribution Fees [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 58 53 40
Advisory and Other Revenue [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 192 269 293
Advisory and Other Revenue [Member] | Advisory [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue 68 99 113
Advisory and Other Revenue [Member] | Other [Member]      
Disaggregation Of Revenue [Line Items]      
Total revenue $ 124 $ 170 $ 180