Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue by Client Type and Investment Style (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Disaggregation Of Revenue [Line Items]
Total revenue		$ 5,276	$ 4,728
Revenue by Client Type [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	4,401	3,778
Revenue by Client Type [Member] | Retail [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	1,061	1,041
Revenue by Client Type [Member] | Equity ETFs [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	1,793	1,562
Revenue by Client Type [Member] | Institutional Active [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	1,016	697
Revenue by Client Type [Member] | Institutional Index [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	238	233
Revenue by Client Type [Member] | Institutional [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	1,254	930
Revenue by Client Type [Member] | Cash Management [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	293	245
Revenue by Client Type [Member] | Long-term [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	4,108	3,533
Revenue by Investment Style [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	4,401	3,778
Revenue by Investment Style [Member] | Equity ETFs [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	1,793	1,562
Revenue by Investment Style [Member] | Equity Non ETFs [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	307	288
Revenue by Investment Style [Member] | Active [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	2,008	1,683
Revenue by Investment Style [Member] | Cash Management [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	293	245
Revenue by Investment Style [Member] | Long-term [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	$ 4,108	$ 3,533

[1] Beginning in the first quarter of 2025, BlackRock reclassified the presentation of the Company's investment advisory, administration fees and securities lending revenue line items to align with the updated presentation of the Company's AUM line items. Such line items have been reclassified for 2024 to conform to this new presentation. See page 11 of Exhibit 99.2 to the Current Report on Form 8-K furnished on April 11, 2025 for the reclassified presentation of the 2024 investment advisory, administration fees and securities lending revenue line items.