Earnings Per Share - Computation of Basic and Diluted EPS under Treasury Stock Method (Detail) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2019 |
Sep. 30, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Earnings Per Share [Abstract] | |||||||||||
| Net income attributable to BlackRock | $ 1,301 | $ 1,119 | $ 1,003 | $ 1,053 | $ 927 | $ 1,216 | $ 1,073 | $ 1,089 | $ 4,476 | $ 4,305 | $ 4,952 |
| Basic weighted-average shares outstanding | 155,195,733 | 155,280,877 | 155,354,552 | 158,268,034 | 158,859,998 | 160,141,506 | 160,980,960 | 161,250,018 | 156,014,343 | 160,301,116 | 162,160,601 |
| Dilutive effect of nonparticipating RSUs and stock options | 1,445,203 | 1,647,616 | 2,254,434 | ||||||||
| Total diluted weighted-average shares outstanding | 156,894,201 | 156,447,387 | 156,360,741 | 159,348,431 | 160,450,266 | 161,378,217 | 162,161,937 | 162,918,961 | 157,459,546 | 161,948,732 | 164,415,035 |
| Basic earnings per share | $ 8.38 | $ 7.21 | $ 6.46 | $ 6.65 | $ 5.84 | $ 7.59 | $ 6.67 | $ 6.75 | $ 28.69 | $ 26.86 | $ 30.54 |
| Diluted earnings per share | $ 8.29 | $ 7.15 | $ 6.41 | $ 6.61 | $ 5.78 | $ 7.54 | $ 6.62 | $ 6.68 | $ 28.43 | $ 26.58 | $ 30.12 |
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- References No definition available.
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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