Earnings Per Share - Computation of Basic and Diluted EPS under Treasury Stock Method (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to BlackRock, Inc.	$ 5,901	$ 4,932	$ 4,476
Basic weighted-average shares outstanding	152,236,047	153,489,422	156,014,343
Total diluted weighted-average shares outstanding	154,404,357	154,840,582	157,459,546
Basic earnings per share	$ 38.76	$ 32.13	$ 28.69
Diluted earnings per share	$ 38.22	$ 31.85	$ 28.43
Restricted Stock Units (RSUs) [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect of	1,507,859	1,275,733	1,445,203
Stock Options [Member]
Earnings Per Share Basic And Diluted [Line Items]
Dilutive effect of	660,451	75,427

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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- Definition

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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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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