Earnings Per Share - Computation of Basic and Diluted Earnings per Share ("EPS") under Treasury Stock Method (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Earnings Per Share Basic And Diluted [Line Items]
Net Income (Loss)	$ 1,659	$ 1,323	$ 5,785	$ 4,426
Diluted net income attributable to BlackRock, Inc.	$ 1,739	$ 1,393	$ 6,066	$ 4,496
Basic weighted-average shares outstanding	154.8	154.9	155.1	154.9
Total diluted weighted-average shares outstanding	164.5	165.2	164.7	159.4
Basic earnings per share	$ 10.72	$ 8.54	$ 37.3	$ 28.57
Diluted earnings per share	$ 10.57	$ 8.43	$ 36.82	$ 28.21
Subco Units [Member]
Earnings Per Share Basic And Diluted [Line Items]
Add: Incremental net income from dilutive securities - NCI - Subco	$ 80	$ 70	$ 281	$ 70
Dilutive effect of	7.6	8.3	7.6	2.8
Restricted Stock Units (RSUs) [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect of	1.7	1.5	1.6	1.2
Employee Stock Option
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect of	0.4	0.5	0.4	0.5

Earnings per share basic and diluted.

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Increase (decrease) in net income from dilutive securities

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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