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Share based compensation arrangement by share based payment award performance measurement period.

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Share based compensation arrangement by share based payment award award vesting rights of grant period.

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Share-based compensation arrangement by share-based payment award vesting rights percentage of grant date stock price.

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The number of additional grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Share based compensation arrangement by share based payment award equity instruments other than options granted in period fair value.

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Share based compensation arrangement by share based payment award equity instruments other than options that cliff vest.

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Share based compensation arrangement by share based payment award requisite service year.

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Vested option exercised period.

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Share-based compensation arrangement by share-based payment award vesting number of installments.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Date the equity-based award expires, in YYYY-MM-DD format.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Price of a single share of a number of saleable stocks of a company.

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Percentage of vesting of award under share-based payment arrangement.

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Intrinsic value of outstanding award under share-based payment arrangement. Excludes share and unit options.

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Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2022 shares	Mar. 31, 2022 USD ($) installment $ / shares shares	Dec. 31, 2021 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, Granted \| shares		714,261
Fair value of RSUs/restricted stock granted to employees \| $		$ 595
RSUs/Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, Granted \| shares	498,633
Award vesting period, years	3 years
Awards to employees cliff vesting \| shares	197,817
RSUs to employees that cliff vest, percentage	100.00%
RSUs to employees that cliff vest, date	Jan. 31, 2025
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of outstanding RSUs \| $		$ 1,600
Stock price \| $ / shares		$ 764.17
Unrecognized stock-based compensation expense \| $		$ 906
Remaining weighted-average period		1 year 7 months 6 days
Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, Granted \| shares		143,846
Award vesting period, years	3 years
Awards to employees cliff vesting \| shares	143,846
RSUs to employees that cliff vest, percentage	100.00%
RSUs to employees that cliff vest, date	Jan. 31, 2025
Intrinsic value of outstanding RSUs \| $		$ 412
Stock price \| $ / shares		$ 764.17
Unrecognized stock-based compensation expense \| $		$ 240
Remaining weighted-average period		1 year 8 months 12 days
Restricted Stock and RSUs, Additional shares granted due to attainment of performance measures \| shares	111,991	111,991
Fair value of RSUs/restricted stock granted to employees \| $		$ 164
Performance Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining weighted-average period		1 year 8 months 12 days
Outstanding, shares under option \| shares		1,817,923	1,817,923
Weighted average exercise price \| $ / shares		$ 513.50	$ 513.50
Award vesting percentage of BlackRock's grant-date stock price		125.00%
Award vesting period of BlackRock's grant-date stock price		5 years
Award performance measurement period		4 years
Award vesting, number of equal installments \| installment		3
Unrecognized stock-based compensation expense \| $		$ 39
Weighted average remaining life of awards		4 years 8 months 12 days
Performance Based Stock Options \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested option exercised period		9 years
Performance Based Stock Options \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service year of awards		2022
Performance Based Stock Options \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service year of awards		2023
Performance Based Stock Options \| Share-based Payment Arrangement, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service year of awards		2024