Selected Quarterly Financial Data - Schedule of Selected Quarterly Financial Data (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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| Quarterly Financial Information Disclosure [Abstract] | |||||||||||
| Revenue | $ 3,977 | $ 3,692 | $ 3,524 | $ 3,346 | $ 3,434 | $ 3,576 | $ 3,605 | $ 3,583 | $ 14,539 | $ 14,198 | $ 13,600 |
| Operating income | 1,538 | 1,502 | 1,278 | 1,233 | 1,246 | 1,396 | 1,440 | 1,375 | 5,551 | 5,457 | 5,254 |
| Net income | 1,334 | 1,119 | 1,013 | 1,060 | 927 | 1,203 | 1,078 | 1,094 | 4,526 | 4,302 | 4,989 |
| Net income attributable to BlackRock, Inc. | $ 1,301 | $ 1,119 | $ 1,003 | $ 1,053 | $ 927 | $ 1,216 | $ 1,073 | $ 1,089 | $ 4,476 | $ 4,305 | $ 4,952 |
| Earnings per share attributable to BlackRock, Inc. common stockholders: Basic | $ 8.38 | $ 7.21 | $ 6.46 | $ 6.65 | $ 5.84 | $ 7.59 | $ 6.67 | $ 6.75 | $ 28.69 | $ 26.86 | $ 30.54 |
| Earnings per share attributable to Black Rock, Inc. common stockholders: Diluted | $ 8.29 | $ 7.15 | $ 6.41 | $ 6.61 | $ 5.78 | $ 7.54 | $ 6.62 | $ 6.68 | $ 28.43 | $ 26.58 | $ 30.12 |
| Weighted-average common shares outstanding: Basic | 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 |
| Weighted-average common shares outstanding: Diluted | 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 |
| Dividend declared per share | $ 3.30 | $ 3.30 | $ 3.30 | $ 3.30 | $ 3.13 | $ 3.13 | $ 2.88 | $ 2.88 | |||
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- Definition Aggregate dividends paid during the period for each share of common stock outstanding. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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 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 net result for the period of deducting operating expenses from operating revenues. No definition available.
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- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Revenues from operations, excluding interest and dividend income. Includes revenues from the following sources: investment banking (underwriting and financial advisory), principal transactions (sales and trading, and investment gains and losses), commissions, asset management, and investment advisory and other services. No definition available.
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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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