Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue by Client Type and Investment Style (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation Of Revenue [Line Items]
Total revenue	$ 7,752	$ 6,509	$ 21,534	$ 17,208
Revenue by Client Type [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	6,036	5,046	17,200	13,901
Revenue by Client Type [Member] \| Retail [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,396	1,177	3,982	3,291
Revenue by Client Type [Member] \| Equity ETFs [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2,762	2,130	7,763	5,798
Revenue by Client Type [Member] \| Institutional Active [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,231	1,149	3,581	3,146
Revenue by Client Type [Member] \| Institutional Index [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	293	272	837	751
Revenue by Client Type [Member] \| Institutional [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	1,524	1,421	4,418	3,897
Revenue by Client Type [Member] \| Cash Management [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	354	318	1,037	915
Revenue by Client Type [Member] \| Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
Disaggregation Of Revenue [Line Items]
Total revenue	5,682	4,728	16,163	12,986
Revenue by Investment Style [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	6,036	5,046	17,200	13,901
Revenue by Investment Style [Member] \| Equity ETFs [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2,762	2,130	7,763	5,798
Revenue by Investment Style [Member] \| Equity Non ETFs [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	399	353	1,126	973
Revenue by Investment Style [Member] \| Active [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	2,521	2,245	7,274	6,215
Revenue by Investment Style [Member] \| Cash Management [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	354	318	1,037	915
Revenue by Investment Style [Member] \| Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
Disaggregation Of Revenue [Line Items]
Total revenue	$ 5,682	$ 4,728	$ 16,163	$ 12,986