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Borrowings - Additional Information (Detail) € in Millions, £ in Millions |  | 1 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
May 06, 2015 EUR (€) | Apr. 30, 2025 EUR (€) | Apr. 30, 2020 USD ($) | Jan. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Apr. 30, 2019 USD ($) | Apr. 30, 2017 USD ($) | Mar. 31, 2017 USD ($) | Dec. 31, 2025 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) | Dec. 31, 2025 GBP (£) | Apr. 30, 2025 USD ($) | Apr. 30, 2025 EUR (€) | May 30, 2023 USD ($) | Dec. 31, 2021 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, covenant terms |  |  |  |  |  |  |  |  |  | The 2025 Credit Facility requires the Company not to exceed a maximum consolidated leverage ratio (ratio of net debt to earnings before interest, taxes, depreciation and amortization, where net debt equals total debt less unrestricted cash) of 3.5 to 1, |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 12,875,000,000 |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  |  | 12,768,000,000 |  | $ 12,314,000,000 |  |  |  |  |  |
Fair Value |  |  |  |  |  |  |  |  |  | 12,546,000,000 |  | 11,700,000,000 |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | 12,875,000,000 |  |  |  |  |  |  |  |
Repayments of long-term borrowings |  |  |  |  |  |  |  |  |  | 796,000,000 |  | 1,000,000,000 | $ 0 |  |  |  |  |
Gain (loss) from net investment hedging, net of tax |  |  |  |  |  |  |  |  |  | (96,000,000) |  | 37,000,000 | (20,000,000) |  |  |  |  |
3.75% Senior Unsecured and Unsubordinated Notes due 2035 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | 1,200,000,000 |  |  |  |  |  | € 1,000 |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 1,200,000,000 |  |  |  |  |  | € 1,000 |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.75% | 3.75% |  |
Debt instrument, maturity date |  |  | Jul. 18, 2035 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, redemption period, end date |  |  | Apr. 18, 2035 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, redemption price, percentage of principal amount redeemed |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured Debt 2027 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  | $ 700,000,000 |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  | $ 700,000,000 |  |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  | 3.20% |  |  |  |  |  |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Mar. 15, 2027 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  | $ 22,000,000 |  |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest is payable semi-annually on March 15 and September 15 of each year |  |  |  |  |  |  |  |
Unsecured Debt 2024 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | New BlackRock Guarantee. On October 1, 2024, in connection with the closing of the GIP Transaction, BlackRock, Inc. also entered into a guarantee (the “New BlackRock Guarantee”) pursuant to which BlackRock, Inc. fully and unconditionally guaranteed, on a senior unsecured basis, the obligations of Old BlackRock with respect to the Old BlackRock Notes. The New BlackRock Guarantee ranks equally in right of payment with all of BlackRock, Inc.'s other unsubordinated indebtedness. The New BlackRock Guarantee will be automatically and unconditionally released and discharged, and BlackRock, Inc. will be released from all obligations under the New BlackRock Guarantee, in certain circumstances as described in the New BlackRock Guarantee. |  |  |  |  |  |  |  |
Commercial Paper [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount available under facility |  |  |  |  |  |  |  |  |  | $ 5,000,000,000 |  |  |  |  |  |  |  |
Amount outstanding under credit facility |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |
2025 Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unsecured revolving credit facility |  |  |  |  |  |  |  |  |  | $ 5,900,000,000 |  |  |  |  | $ 500,000,000 |  |  |
Maximum leverage ratio required by credit facility |  |  |  |  |  |  |  |  |  | 3.5 to 1 |  |  |  |  |  |  |  |
Additional amount available, subject to lender credit approval |  |  |  |  |  |  |  |  |  | $ 1,400,000,000 |  |  |  |  |  |  |  |
Maximum amount available under facility |  |  |  |  |  |  |  |  |  | 7,300,000,000 |  |  |  |  |  |  |  |
Amount outstanding under credit facility |  |  |  |  |  |  |  |  |  | $ 0 |  |  |  |  |  |  |  |
Line of credit facility, covenant compliance |  |  |  |  |  |  |  |  |  | less than 1 to 1 |  |  |  |  |  |  |  |
2025 Subsidiary Credit Facility [Member] | Subsidiaries [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum amount available under facility |  |  |  |  |  |  |  |  |  | $ 34,000,000 |  |  |  | £ 25 |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |
Notes due 2025 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  | € 38 |  |  |  |  |  |  | 44,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  | annually on July 18 of each year |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) from net investment hedging, net of tax |  |  |  |  |  |  |  |  |  | (96,000,000) |  | 37,000,000 | (20,000,000) |  |  |  |  |
Gain (loss) from net investment hedging, tax expense (benefit) |  |  |  |  |  |  |  |  |  | (30,000,000) |  | $ 12,000,000 | $ (6,000,000) |  |  |  |  |
March 2024 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | 3,000,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | 3,000,000,000 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 152,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest on the March 2024 Notes of approximately $152 million per year is payable semi-annually on March 14 and September 14 of each year, which commenced on September 14, 2024. |  |  |  |  |  |  |  |
July 2024 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 2,500,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | 2,500,000,000 |  |  |  |  |  |  |  |
July 2027 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 37,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest on the July 2027 Notes of approximately $37 million per year is payable semi-annually on January 26 and July 26 of each year, beginning January 26, 2025. |  |  |  |  |  |  |  |
July 2035 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 25,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest on the 2035 Notes and 2055 Notes of approximately $25 million and $64 million per year, respectively, is payable semi-annually on January 8 and July 8 of each year, beginning January 8, 2025. |  |  |  |  |  |  |  |
July 2055 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 64,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest on the 2035 Notes and 2055 Notes of approximately $25 million and $64 million per year, respectively, is payable semi-annually on January 8 and July 8 of each year, beginning January 8, 2025. |  |  |  |  |  |  |  |
4.70% Notes due March 2029 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 500,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 500,000,000 |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  | 4.70% |  |  |  | 4.70% |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Mar. 14, 2029 |  |  |  |  |  |  |  |
5.00% Notes due 2034 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 1,000,000,000 |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  |  | 994,000,000 |  |  |  |  |  |  |  |
Fair Value |  |  |  |  |  |  |  |  |  | 1,032,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 1,000,000,000 |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  | 5.00% |  |  |  | 5.00% |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Mar. 14, 2034 |  |  |  |  |  |  |  |
5.25% Notes due 2054 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 1,500,000,000 |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  |  | 1,470,000,000 |  |  |  |  |  |  |  |
Fair Value |  |  |  |  |  |  |  |  |  | 1,436,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 1,500,000,000 |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  | 5.25% |  |  |  | 5.25% |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Mar. 14, 2054 |  |  |  |  |  |  |  |
4.60% Notes due July 2027 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 800,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 800,000,000 |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  | 4.60% |  |  |  | 4.60% |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Jul. 26, 2027 |  |  |  |  |  |  |  |
4.90% Notes due 2035 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 500,000,000 |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  |  | 495,000,000 |  |  |  |  |  |  |  |
Fair Value |  |  |  |  |  |  |  |  |  | 510,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 500,000,000 |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  | 4.90% |  |  |  | 4.90% |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Jan. 08, 2035 |  |  |  |  |  |  |  |
5.35% Notes due 2055 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 1,200,000,000 |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  |  | 1,186,000,000 |  |  |  |  |  |  |  |
Fair Value |  |  |  |  |  |  |  |  |  | 1,168,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 1,200,000,000 |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  | 5.35% |  |  |  | 5.35% |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Jan. 08, 2055 |  |  |  |  |  |  |  |
4.75% Notes due 2033 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 1,250,000,000 | [1] |  |  |  |  |  | $ 1,250,000,000 |
Borrowings | [1] |  |  |  |  |  |  |  |  | 1,235,000,000 |  |  |  |  |  |  |  |
Fair Value | [1] |  |  |  |  |  |  |  |  | 1,277,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 1,250,000,000 | [1] |  |  |  |  |  | $ 1,250,000,000 |
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.75% |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | May 25, 2033 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 59,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest of approximately $59 million per year is payable semi-annually on May 25 and November 25 of each year, commencing on November 25, 2023 |  |  |  |  |  |  |  |
Debt instrument, redemption period, end date |  |  |  |  |  |  |  |  |  | Feb. 25, 2033 |  |  |  |  |  |  |  |
Debt Instrument, redemption price, percentage of principal amount redeemed |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
1.90% Notes due 2031 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  | $ 1,250,000,000 |  |  |  |  |  | $ 1,250,000,000 | [1] |  |  |  |  |  |  |
Borrowings | [1] |  |  |  |  |  |  |  |  | 1,244,000,000 |  |  |  |  |  |  |  |
Fair Value | [1] |  |  |  |  |  |  |  |  | 1,123,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  | $ 1,250,000,000 |  |  |  |  |  | $ 1,250,000,000 | [1] |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  | 1.90% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Jan. 28, 2031 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  | $ 24,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest of approximately $24 million per year is payable semi-annually on January 28 and July 28 of each year, which commenced on July 28, 2020. |  |  |  |  |  |  |  |
Debt instrument, redemption period, end date |  |  |  |  |  |  |  |  |  | Oct. 28, 2030 |  |  |  |  |  |  |  |
Debt Instrument, redemption price, percentage of principal amount redeemed |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
2.10% Notes due 2032 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  | $ 1,000,000,000 | [1] |  |  |  |  |  |  | $ 1,000,000,000
Borrowings | [1] |  |  |  |  |  |  |  |  | 991,000,000 |  |  |  |  |  |  |  |
Fair Value | [1] |  |  |  |  |  |  |  |  | 883,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  | $ 1,000,000,000 | [1] |  |  |  |  |  |  | $ 1,000,000,000
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.10%
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Feb. 25, 2032 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 21,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest of approximately $21 million per year is payable semi-annually on February 25 and August 25 of each year, which commenced on February 25, 2022. |  |  |  |  |  |  |  |
Debt instrument, redemption period, end date |  |  |  |  |  |  |  |  |  | Nov. 25, 2031 |  |  |  |  |  |  |  |
Debt Instrument, redemption price, percentage of principal amount redeemed |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
3.375% Notes due June 2022 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 750,000,000
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 750,000,000
Debt instrument, interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.375%
2.40% Notes due 2030 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  | $ 1,000,000,000 |  |  |  |  | $ 1,000,000,000 | [1] |  |  |  |  |  |  |
Borrowings | [1] |  |  |  |  |  |  |  |  | 997,000,000 |  |  |  |  |  |  |  |
Fair Value | [1] |  |  |  |  |  |  |  |  | 935,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  | $ 1,000,000,000 |  |  |  |  | $ 1,000,000,000 | [1] |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  | 2.40% |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Apr. 30, 2030 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  | $ 24,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest of approximately $24 million per year is payable semi-annually on April 30 and October 30 of each year, which commenced on April 30, 2020. |  |  |  |  |  |  |  |
Debt instrument, redemption period, end date |  |  |  |  |  |  |  |  |  | Jan. 30, 2030 |  |  |  |  |  |  |  |
Debt Instrument, redemption price, percentage of principal amount redeemed |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
3.25% Notes due 2029 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding |  |  |  |  |  |  | $ 1,000,000,000 |  |  | $ 1,000,000,000 | [1] |  |  |  |  |  |  |
Borrowings | [1] |  |  |  |  |  |  |  |  | 995,000,000 |  |  |  |  |  |  |  |
Fair Value | [1] |  |  |  |  |  |  |  |  | 978,000,000 |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  | $ 1,000,000,000 |  |  | $ 1,000,000,000 | [1] |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  | 3.25% |  |  |  |  |  |  |  |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  | Apr. 30, 2029 |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  | $ 33,000,000 |  |  |  |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | Interest is payable semi-annually on April 30 and October 30 of each year, which commenced on October 30, 2019 |  |  |  |  |  |  |  |
Debt instrument, redemption period, end date |  |  |  |  |  |  |  |  |  | Jan. 30, 2029 |  |  |  |  |  |  |  |
5.00% Notes due 2019 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  | 5.00% |  |  |  |  |  |  |  |  |  |  |  |
Repayments of long-term borrowings |  |  |  |  |  | $ 1,000,000,000 |  |  |  |  |  |  |  |  |  |  |  |
6.25% Notes due 2017 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate |  |  |  |  |  |  |  | 6.25% |  |  |  |  |  |  |  |  |  |
Repayments of long-term borrowings |  |  |  |  |  |  |  | $ 700,000,000 |  |  |  |  |  |  |  |  |  |
Long-term debt, maturity date |  |  |  |  |  |  |  | 2017-09 |  |  |  |  |  |  |  |  |  |
1.25% Notes due 2025 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amounts outstanding | € |  | € 700 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount | € |  | € 700 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate |  | 1.25% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, maturity date |  | May 30, 2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, Approximate annual interest expense |  |  |  |  |  |  |  |  |  | $ 11,000,000 |  |  |  |  |  |  |  |
Debt instrument, payment terms |  |  |  |  |  |  |  |  |  | annually on May 6 of each year |  |  |  |  |  |  |  |
[1] | Issued by Old BlackRock and guaranteed by BlackRock, Inc.

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