BlackRock (BLK) 10-Q 9 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	BLK
Entity Registrant Name	BlackRock Inc.
Entity Central Index Key	1,364,742
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		160,169,656

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 5,978	$ 6,894
Accounts receivable	2,677	2,699
Investments	2,050	1,981
Separate account assets	142,871	149,937
Separate account collateral held under securities lending agreements	27,247	24,190
Property and equipment (net of accumulated depreciation of $698 and $658 at March 31,2018 and December 31, 2017, respectively)	589	592
Intangible assets (net of accumulated amortization of $210 and $219 at March 31, 2018 and December 31, 2017, respectively)	17,378	17,389
Goodwill	13,217	13,220
Other assets	2,157	1,636
Total assets	216,017	220,241
Liabilities
Accrued compensation and benefits	788	2,153
Accounts payable and accrued liabilities	1,421	1,161
Liabilities of consolidated variable interest entities	425	369
Borrowings	5,036	5,014
Separate account liabilities	142,871	149,937
Separate account collateral liabilities under securities lending agreements	27,247	24,190
Deferred income tax liabilities	3,516	3,527
Other liabilities	2,130	1,626
Total liabilities	183,434	187,977
Commitments and contingencies (Note 12)
Temporary equity
Redeemable noncontrolling interests	561	416
Permanent Equity
Shares authorized: 500,000,000 at March 31, 2018 and December 31, 2017; Shares issued: 171,252,185 at March 31, 2018 and December 31, 2017; Shares outstanding: 160,308,362 and 159,977,115 at March 31, 2018 and December 31, 2017, respectively	2	2
Preferred stock (Note 17)	0	0
Additional paid-in capital	18,856	19,256
Retained earnings	17,529	16,939
Accumulated other comprehensive loss	(301)	(432)
Treasury stock, common, at cost (10,943,823 and 11,275,070 shares held at March 31, 2018 and December 31, 2017, respectively)	(4,108)	(3,967)
Total BlackRock, Inc. stockholders’ equity	31,978	31,798
Nonredeemable noncontrolling interests	44	50
Total permanent equity	32,022	31,848
Total liabilities, temporary equity and permanent equity	216,017	220,241
Consolidated Variable Interest Entities [Member]
Assets
Cash and cash equivalents	103	144
Investments	1,637	1,493
Other assets	113	66
Liabilities
Total liabilities	425	369
Permanent Equity
Nonredeemable noncontrolling interests	$ 518	$ 375

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Property and equipment, accumulated depreciation	$ 698	$ 658
Intangible assets, accumulated amortization	$ 210	$ 219
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	171,252,185	171,252,185
Common stock, shares outstanding	160,308,362	159,977,115
Treasury stock, common shares	10,943,823	11,275,070

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue
Total investment advisory, administration fees and securities lending revenue	$ 2,947	$ 2,523
Investment advisory performance fees	70	70
Technology and risk management revenue	184	154
Distribution fees	311	287
Advisory and other revenue	71	58
Total revenue	3,583	3,092
Expense
Employee compensation and benefits	1,121	1,021
Distribution and servicing costs	432	401
Direct fund expense	261	206
General and administration	383	296
Amortization of intangible assets	11	25
Total expense	2,208	1,949
Operating income	1,375	1,143
Nonoperating income (expense)
Net gain (loss) on investments	15	51
Interest and dividend income	15	7
Interest expense	(46)	(65)
Total nonoperating income (expense)	(16)	(7)
Income before income taxes	1,359	1,136
Income tax expense	265	268
Net income	1,094	868
Net income (loss) attributable to noncontrolling interests	5	9
Net income attributable to BlackRock, Inc.	$ 1,089	$ 859
Earnings per share attributable to BlackRock, Inc. common stockholders:
Basic	$ 6.75	$ 5.27
Diluted	6.68	5.21
Cash dividends declared and paid per share	$ 2.88	$ 2.50
Weighted-average common shares outstanding:
Basic	161,250,018	163,016,599
Diluted	162,918,961	164,856,183
Related Parties [Member]
Revenue
Total investment advisory, administration fees and securities lending revenue	$ 2,112	$ 1,768
Other Third Parties [Member]
Revenue
Total investment advisory, administration fees and securities lending revenue	$ 835	$ 755

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 1,094	$ 868
Other comprehensive income:
Foreign currency translation adjustments	[1]	137	40
Other			(1)
Other comprehensive income (loss)		137	39
Comprehensive income		1,231	907
Less: Comprehensive income (loss) attributable to noncontrolling interests		5	9
Comprehensive income attributable to BlackRock, Inc.		$ 1,226	$ 898
[1]	Amounts for the three months ended March 31, 2018 and 2017 include a loss from a net investment hedge of $16 million (net of a tax benefit of $5 million) and $7 million (net of a tax benefit of $4 million), respectively.

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Gains (loss) from net investment hedging, net of tax	$ (16)	$ (7)
Gain (loss) from net investment hedging, tax	$ (5)	$ (4)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Additional Paid-in Capital [Member]		Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock Common [Member]	Total BlackRock Stockholders' Equity [Member]	Nonredeemable Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests / Temporary Equity [Member]
Balance at Dec. 31, 2016	$ 29,140	$ 19,339	[1]	$ 13,650	$ (716)	$ (3,185)	$ 29,088	$ 52	$ 194
Net income	860			859			859	1	8
Dividends paid	(447)			(447)			(447)
Stock-based compensation	162	162	[1]				162
PNC preferred stock capital contribution	193	193	[1]				193
Retirement of preferred stock	(193)	(193)	[1]				(193)
Issuance of common shares related to employee stock transactions	3	(573)	[1]			576	3
Employee tax withholdings related to employee stock transactions	(287)					(287)	(287)
Shares repurchased	(275)					(275)	(275)
Subscriptions (redemptions/distributions) — noncontrolling interest holders	(3)							(3)	135
Net consolidations (deconsolidations) of sponsored investment funds									(28)
Other comprehensive income (loss)	39				39		39
Adoption of new accounting pronouncements	1	3	[1]	(2)			1
Balance at Mar. 31, 2017	29,193	18,931	[1]	14,060	(677)	(3,171)	29,143	50	309
Balance at Dec. 31, 2017	31,848	19,258	[2]	16,939	(432)	(3,967)	31,798	50	416
Net income	1,088			1,089			1,089	(1)	6
Dividends paid	(505)			(505)			(505)
Stock-based compensation	175	175	[2]				175
PNC preferred stock capital contribution	58	58	[2]				58
Retirement of preferred stock	(58)	(58)	[2]				(58)
Issuance of common shares related to employee stock transactions	3	(575)	[2]			578	3
Employee tax withholdings related to employee stock transactions	(384)					(384)	(384)
Shares repurchased	(335)					(335)	(335)
Subscriptions (redemptions/distributions) — noncontrolling interest holders	(5)							(5)	352
Net consolidations (deconsolidations) of sponsored investment funds									(213)
Other comprehensive income (loss)	137				137		137
Adoption of new accounting pronouncements				6	(6)
Balance at Mar. 31, 2018	$ 32,022	$ 18,858	[2]	$ 17,529	$ (301)	$ (4,108)	$ 31,978	$ 44	$ 561
[1]	Amounts include $2 million of common stock at both March 31, 2017 and December 31, 2016.
[2]	Amounts include $2 million of common stock at both March 31, 2018 and December 31, 2017.

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Additional Paid-in Capital, value of stock	$ 32,022	$ 31,848	$ 29,193	$ 29,140
Common Stock [Member]
Additional Paid-in Capital, value of stock	$ 2	$ 2	$ 2	$ 2

Condensed Consolidated Stateme9

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net income	$ 1,094	$ 868
Adjustments to reconcile net income to cash flows from operating activities:
Depreciation and amortization	53	63
Stock-based compensation	175	162
Deferred income tax expense (benefit)	10	198
Net (gains) losses within consolidated VIEs	(2)	(33)
Net (purchases) proceeds within consolidated VIEs	(342)	(96)
(Earnings) losses from equity method investees	(33)	(32)
Distributions of earnings from equity method investees	10	5
Changes in operating assets and liabilities:
Accounts receivable	35	5
Investments, trading	(21)	(188)
Other assets	(474)	(975)
Accrued compensation and benefits	(1,362)	(1,110)
Accounts payable and accrued liabilities	268	59
Other liabilities	448	910
Cash flows from operating activities	(141)	(164)
Cash flows from investing activities
Purchases of investments	(94)	(61)
Proceeds from sales and maturities of investments	122	21
Distributions of capital from equity method investees	5	10
Net consolidations (deconsolidations) of sponsored investment funds (VIEs/VREs)	(53)
Purchases of property and equipment	(33)	(19)
Cash flows from investing activities	(53)	(49)
Cash flows from financing activities
Proceeds from long-term borrowings		697
Cash dividends paid	(505)	(447)
Repurchases of common stock	(719)	(562)
Net (redemptions/distributions paid)/subscriptions received from noncontrolling interest holders	347	132
Other financing activities	3
Cash flows from financing activities	(874)	(180)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	115	32
Net increase (decrease) in cash, cash equivalents and restricted cash	(953)	(361)
Cash, cash equivalents and restricted cash, beginning of period	7,096	6,192
Cash, cash equivalents and restricted cash, end of period	6,143	5,831
Supplemental disclosure of cash flow information:
Interest	29	40
Income taxes (net of refunds)	74	82
Supplemental schedule of noncash investing and financing transactions:
Issuance of common stock	575	573
PNC preferred stock capital contribution	58	193
Increase (decrease) in noncontrolling interests due to net consolidation (deconsolidation) of sponsored investment funds	$ (213)	$ (28)

Business Overview

Business Overview	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business Overview	1. Business Overview BlackRock, Inc. (together, with its subsidiaries, unless the context otherwise indicates, “BlackRock” or the “Company”) is a leading publicly traded investment management firm providing a broad range of investment and risk management services to institutional and retail clients worldwide. BlackRock’s diverse platform of alpha-seeking active, index and cash management investment strategies across asset classes enables the Company to tailor investment outcomes and asset allocation solutions for clients. Product offerings include single- and multi-asset portfolios investing in equities, fixed income, alternatives and money market instruments. Products are offered directly and through intermediaries in a variety of vehicles, including open-end and closed-end mutual funds, iShares ® Aladdin ® At March 31, 2018, The PNC Financial Services Group, Inc. (“PNC”) held 21.2% of the Company’s voting common stock and 21.7% of the Company’s capital stock, which includes outstanding common and nonvoting preferred stock.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation . These condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and include the accounts of the Company and its controlled subsidiaries. Noncontrolling interests on the condensed consolidated statements of financial condition represents the portion of consolidated sponsored investment funds in which the Company does not have direct equity ownership. Accounts and transactions between consolidated entities have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expense during the reporting periods. Actual results could differ from those estimates. Certain financial information that normally is included in annual financial statements, including certain financial statement footnotes, is not required for interim reporting purposes and has been condensed or omitted herein. These condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements and notes related thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, which was filed with the Securities and Exchange Commission (“SEC”) on February 28, 2018 (“2017 Form 10-K”). The interim financial information at March 31, 2018 and for the three months ended March 31, 2018 and 2017 is unaudited. However, in the opinion of management, the interim information includes all normal recurring adjustments necessary for the fair presentation of the Company’s results for the periods presented. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year. Certain prior period presentations and disclosures, while not required to be recast, were reclassified to ensure comparability with current period classifications. Accounting Pronouncements Adopted in the Three Months Ended March 31, 2018. Revenue from Contracts with Customers. The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2 014-09, , and several amendments (collectively, “ASU 2014-09”). ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most previous revenue recognition guidance, including industry-specific guidance. The guidance also changes the accounting for certain contract costs and revises the criteria for determining if an entity is acting as a principal or agent in certain arrangements. The Company adopted ASU 2014-09 effective January 1, 2018 on a full retrospective basis, which required the Company to recast 2016 and 2017 previously reported amounts. The key impact of the standard relates to the Company’s presentation of certain revenue contracts and associated contract costs. The most significant of these changes relates to the presentation of certain distribution costs, which were previously presented net against revenue (contra-revenue) and are now presented as an expense on a gross basis. Revenue recognition related to investment advisory, administration fees and securities lending revenue as well as performance fees remained unchanged, which represents a substantial portion of the Company’s revenue. However, under ASU 2014-09, the Company may recognize certain performance fees, including carried interest, earlier than under the prior revenue recognition guidance. The impact to the condensed consolidated statement of financial condition upon adoption was related to a change in timing of recognition for certain technology and risk management revenue and related costs that resulted in an increase to other assets and other liabilities of $19 million and $25 million, respectively. The cumulative adjustment to retained earnings as of January 1, 2016 was a net decrease of $6 million. The following table presents the impact of the adoption to the condensed consolidated statement of income for the three months ended March 31, 2017. Three Months Ended March 31, 2017 (in millions, except shares and per share data) Previously Reported Adoption of the New Revenue Standard Adjustment Recast Total revenue $ 2,824 $ 268 $ 3,092 Total expense 1,677 272 1,949 Operating income $ 1,147 $ (4 ) $ 1,143 Income tax expense $ 269 $ (1 ) $ 268 Net income $ 871 $ (3 ) $ 868 Net income attributable to BlackRock, Inc. $ 862 $ (3 ) $ 859 Earnings per share attributable to BlackRock, Inc. common stockholders: Basic $ 5.29 $ (0.02 ) $ 5.27 Diluted $ 5.23 $ (0.02 ) $ 5.21 Recognition and Measurement of Financial Instruments . In January 2016, the FASB issued ASU 2016-01, (“ASU 2016-01”). ASU 2016-01 amends guidance on the classification and measurement of financial instruments, including requiring an entity to measure substantially all equity securities (other than those accounted for under the equity method of accounting) at fair value through earnings. ASU 2016-01 also amends certain disclosure requirements associated with the fair value of financial instruments. The Company adopted ASU 2016-01 using a modified retrospective approach on January 1, 2018. The reclassification of unrealized gains (losses) on equity securities within accumulated other comprehensive income to retained earnings was not material upon adoption. Cash Flow Classification. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), which amends and clarifies the current guidance to reduce diversity in practice of the classification of certain cash receipts and payments in the consolidated statement of cash flows. The Company adopted ASU 2016-15 on January 1, 2018 retrospectively to all periods presented . The adoption of ASU 2016-15 did not have a material impact on the condensed consolidated statement of cash flows. Restricted Cash. In November 2016, the FASB issued 2016-18, , which clarifies the classification and presentation of restricted cash in the statement of cash flows (“ASU 2016-18”). The Company adopted ASU 2016-18 on January 1, 2018 retrospectively to all periods presented. The adoption of ASU 2016-18 did not have a material impact on the condensed consolidated statement of cash flows. See Note 3, , for additional disclosure requirements related to restricted cash. Reclassifications from Accumulated Other Comprehensive Income. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (“ASU 2018-02”). ASU 2018-02 allows reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. The Company adopted ASU 2018-02 prospectively on January 1, 2018. The adoption of ASU 2018-02 did not have a material impact on the condensed consolidated statement of financial condition. Revenue Recognition. Revenue is recognized upon transfer of control of promised services to customers in an amount that reflects consideration to which the Company expects to be entitled in exchange for those services (the “transaction price”). The Company enters into contracts that can include multiple services, which are accounted for separately if they are determined to be distinct. Consideration for the Company’s services is generally in the form of variable consideration because the amount of fees is subject to market conditions that are outside of the Company’s influence. The Company includes variable consideration as part of its transaction price when it is no longer probable of significant reversal, i.e. when the associated uncertainty is resolved. For some contracts with customers, the Company has discretion to involve a third party in providing services to the customer. Generally, the Company is deemed to be the principal in these arrangements because the Company controls the promised services before they are transferred to customers, and accordingly presents the revenue gross of related costs. Investment Advisory, Administration Fees and Securities Lending Revenue. Investment advisory and administration fees are recognized as the services are performed over time. Such fees are primarily based on agreed-upon percentages of net asset value, assets under management (“AUM”) or committed capital. These fees are affected by changes in AUM, including market appreciation or depreciation, foreign exchange translation and net inflows or outflows. Investment advisory and administration fees for investment funds are shown net of fees waived pursuant to contractual expense limitations of the funds or voluntary waivers. In addition, the Company may contract with third parties to provide sub-advisory services on its behalf. The Company presents the investment advisory fees and associated costs to such advisors on a gross basis in the condensed consolidated statements of income where it is deemed to be the principal. The Company earns revenue by lending securities on behalf of clients, primarily to highly rated banks and broker-dealers. Revenue is recognized over time as services are performed. Generally, the securities lending fees are shared between the Company and the funds or other third-party accounts managed by the Company from which the securities are borrowed. Investment Advisory Performance Fees / Carried Interest. The Company receives investment advisory performance fees, including incentive allocations (carried interest) from certain actively managed investment funds and certain separately managed accounts. These performance fees are dependent upon exceeding specified relative or absolute investment return thresholds, which may vary by product or account, and include monthly, quarterly, annually or longer measurement periods. A portion of the fees the Company recognizes may be partially related to the services performed in prior periods that meet the recognition criteria in the current period. The Company is allocated carried interest from certain alternative investment products upon exceeding performance thresholds. BlackRock may be required to reverse/return all, or part, of such carried interest allocations depending upon future performance of these funds. Therefore, carried interest subject to such clawback provisions is recorded in investments/investments of consolidated VIEs or cash/cash of consolidated VIEs to the extent that it is distributed, on its condensed consolidated statements of financial condition. Performance fees, including carried interest, are recognized when it is determined that they are no longer probable of significant reversal (such as upon the sale of a fund’s investment or when the amount of AUM becomes known as of the end of a specified measurement period). Significant judgement is involved in making such determination. At each reporting date, the Company considers various factors in estimating performance fees to be recognized, including carried interest. These factors include but are not limited to whether: (1) the fees are dependent on the market and thus are highly susceptible to factors outside the Company’s influence; (2) the fees have a large number and a broad range of possible amounts; and (3) the funds or separately managed accounts have the ability to invest or reinvest its sales proceeds. The Company records a contract liability for deferred carried interest to the extent it receives cash or capital allocations related to carried interest prior to meeting the revenue recognition criteria. At March 31, 2018 and December 31, 2017, the Company had $224 million and $219 million, respectively, of deferred carried interest recorded in other liabilities/other liabilities of consolidated VIEs on the condensed consolidated statements of financial condition. A portion of the deferred carried interest may also be paid to certain employees. The ultimate timing of the recognition of performance fee revenue and related compensation expense, if any, for these products is unknown. Technology and risk management revenue. BlackRock offers investment management technology systems, risk management services, wealth management and digital distribution tools on a fee basis. Clients include banks, insurance companies, official institutions, pension funds, asset managers, retail distributors and other investors. Fees earned for technology and risk management revenue are recorded as services are performed and are generally determined using the value of positions on the Aladdin platform or on a fixed-rate basis. Distribution Fees. The Company accounts for fund distribution services and shareholder servicing as distinct services, separate from fund management services, because customers can benefit from each of the services on their own and because the services are separately identifiable (that is, the nature of the promised services is to transfer each service individually). The Company records upfront and ongoing sales commissions as distribution fee revenue for serving as the principal underwriter and/or distributor for certain mutual funds that it manages. The Company recognizes the upfront fees for front-end load funds on a trade date basis when the services are performed and the amount the Company is entitled to is known. The on-going distribution fees are generally based on net asset values and are recognized when the amount is known. Distribution services are satisfied at a point in time. Consequently, a portion of the on-going distribution fees the Company recognized may be related to the services performed in prior periods that met the recognition criteria in the current period. The Company recognizes ongoing shareholder servicing fee revenue when and as shareholder services are performed over time. The Company contracts with third parties for various fund distribution services and shareholder servicing of certain funds to be performed on its behalf. These arrangements are generally priced as a portion of the fee paid to the Company by the fund or as an agreed-upon percentage of net asset value. The Company presents its distribution fees and distribution and servicing costs incurred on a gross basis in the condensed consolidated statements of income as it is deemed to be the principal in such transactions. Advisory and other revenue. Advisory and other revenue primarily includes fees earned for advisory services, fees earned for transition management services primarily comprised of commissions recognized in connection with buying and selling securities on behalf of customers, and equity method investment earnings related to certain strategic investments. Advisory services fees are determined using fixed-rate fees and are recognized over time as the related services are performed. Commissions related to transition management services are recorded on a trade-date basis as securities transactions occur. Investments. Investments in Debt Securities. BlackRock classifies debt investments as available-for-sale, held-to-maturity or trading based on the Company’s intent to sell the security or, its intent and ability to hold the debt security to maturity. Available-for-sale debt securities are those securities that are not classified as trading or held-to-maturity. Available-for-sale debt securities include certain investments in collateralized loan obligations (“CLOs”) and are carried at fair value on the condensed consolidated statements of financial condition with changes in fair value recorded in the accumulated other comprehensive income (loss) component of stockholders’ equity in the period of the change. Upon the disposition of an available-for-sale security, the Company reclassifies the gain or loss on the security from accumulated other comprehensive income (loss) to nonoperating income (expense) on the condensed consolidated statements of income. Held-to-maturity debt securities are purchased with the positive intent and ability to be held to maturity and are recorded at amortized cost on the condensed consolidated statements of financial condition. Trading securities are those investments that are purchased principally for the purpose of selling them in the near term. Trading securities are carried at fair value on the condensed consolidated statements of financial condition with changes in fair value recorded in nonoperating income (expense) on the condensed consolidated statements of income in the period of the change. Trading securities include certain investments in CLOs for which the fair value option is elected in order to reduce operational complexity of bifurcating embedded derivatives. Investments in Equity Securities. Equity securities are generally carried at fair value on the condensed consolidated statements of financial condition with changes in the fair value recorded through net income (“FVTNI”) within nonoperating income (expense) in the period of change. For nonmarketable equity securities, the Company generally elected to apply the practicality exception to apply fair value measurement, under which such securities will be measured at cost, less impairment, plus or minus observable price changes for identical or similar securities of the same issuer with such changes recorded in the condensed consolidated statements of income in the period of the change. Dividends received from the investment are recorded as dividend income within nonoperating income (expense). Equity Method. For equity investments where BlackRock does not control the investee, and where it is not the primary beneficiary (“PB”) of a VIE, but can exert significant influence over the financial and operating policies of the investee, the Company follows the equity method of accounting. BlackRock’s share of the investee’s underlying net income or loss is recorded as net gain (loss) on investments within nonoperating income (expense) and as other revenue for certain strategic investments since such companies are considered to be an extension of BlackRock’s core business. BlackRock’s share of net income of the investee is recorded based upon the most current information available at the time, which may precede the date of the condensed consolidated statement of financial condition. Distributions received from the investment reduce the Company’s carrying value of the investee and the cost basis if deemed to be a return of capital. Impairments of Investments. Management periodically assesses equity method, available-for-sale and held-to-maturity investments for other-than-temporary impairment (“OTTI”). If an OTTI exists, an impairment charge would be recorded in the condensed consolidated statements of income. For equity method investments and held-to-maturity investments, if circumstances indicate that an OTTI may exist, the investments are evaluated using market values, where available, or the expected future cash flows of the investment. If the Company determines an OTTI exists, an impairment charge is recognized for the excess of the carrying amount of the investment over its estimated fair value. For the Company’s investments in CLOs, the Company reviews cash flow estimates over the life of each CLO investment. On a quarterly basis, if the present value of the estimated future cash flows is lower than the carrying value of the investment and there is an adverse change in estimated cash flows, an impairment is considered to be other-than-temporary. An impairment charge is recognized for the excess of the carrying amount of the investment over its estimated fair value. In addition, for nonmarketable equity securities that are accounted for under the measurement alternative to fair value, the Company applies the simplified impairment model that does not require the Company to consider whether the impairment is other than temporary. Fair Value Measurements. Hierarchy of Fair Value Inputs . The Company uses a fair value hierarchy that prioritizes inputs to valuation approaches used to measure fair value. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. Assets and liabilities measured and reported at fair value are classified and disclosed in one of the following categories: Level 1 Inputs: Quoted prices (unadjusted) in active markets for identical assets or liabilities at the reporting date. • Level 1 assets may include listed mutual funds, ETFs, listed equities and certain exchange-traded derivatives. Level 2 Inputs: Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities that are not active; quotes from pricing services or brokers for which the Company can determine that orderly transactions took place at the quoted price or that the inputs used to arrive at the price are observable; and inputs other than quoted prices that are observable, such as models or other valuation methodologies. • Level 2 assets may include debt securities, investments in CLOs, short-term floating-rate notes, asset-backed securities, securities held within consolidated hedge funds, restricted public securities valued at a discount, as well as over-the-counter derivatives, including interest and inflation rate swaps and foreign currency exchange contracts that have inputs to the valuations that generally can be corroborated by observable market data. Level 3 Inputs: Unobservable inputs for the valuation of the asset or liability, which may include nonbinding broker quotes. Level 3 assets include investments for which there is little, if any, market activity. These inputs require significant management judgment or estimation. • Level 3 assets may include direct private equity investments held within consolidated funds and investments in CLOs. • Level 3 liabilities include contingent liabilities related to acquisitions valued based upon discounted cash flow analyses using unobservable market data. Significance of Inputs. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the financial instrument. Valuation Approaches. The fair values of certain Level 3 assets and liabilities were determined using various valuation approaches as appropriate, including third-party pricing vendors, broker quotes and market and income approaches. Such quotes and modeled prices are evaluated for reasonableness through various procedures, including due diligence reviews of third-party pricing vendors, variance analyses, consideration of the current market environment and other analytical procedures. A significant number of inputs used to value equity, debt securities and investments in CLOs is sourced from third-party pricing vendors. Generally, prices obtained from pricing vendors are categorized as Level 1 inputs for identical securities traded in active markets and as Level 2 for other similar securities if the vendor uses observable inputs in determining the price. Annually, BlackRock’s internal valuation committee or other designated groups review both the valuation approaches, including the general assumptions and methods used to value various asset classes, and operational processes with these vendors. On a quarterly basis, meetings are held with key vendors to identify any significant changes to the vendors’ processes. In addition, quotes obtained from brokers generally are nonbinding and categorized as Level 3 inputs. However, if the Company is able to determine that market participants have transacted for the asset in an orderly manner near the quoted price or if the Company can determine that the inputs used by the broker are observable, the quote is classified as a Level 2 input. Investments Measured at Net Asset Values. As a practical expedient, the Company uses net asset value (“NAV”) as the fair value for certain investments. The inputs to value these investments may include BlackRock capital accounts for its partnership interests in various alternative investments, including hedge funds, real assets and private equity funds, which may be adjusted by using the returns of certain market indices. The various partnerships generally are investment companies, which record their underlying investments at fair value based on fair value policies established by management of the underlying fund. Fair value policies at the underlying fund generally require the fund to utilize pricing/valuation information from third-party sources, including independent appraisals. However, in some instances, current valuation information for illiquid securities or securities in markets that are not active may not be available from any third-party source or fund management may conclude that the valuations that are available from third-party sources are not reliable. In these instances, fund management may perform model-based analytical valuations that could be used as an input to value these investments. Derivative Instruments and Hedging Activities . The Company does not use derivative financial instruments for trading or speculative purposes. The Company uses derivative financial instruments primarily for purposes of hedging exposures to fluctuations in foreign currency exchange rates of certain assets and liabilities, and market exposures for certain seed investments. However, certain consolidated sponsored investment funds may also utilize derivatives as a part of their investment strategy. Changes in the fair value of the Company’s derivative financial instruments are recognized in earnings and, where applicable, are offset by the corresponding gain or loss on the related foreign-denominated assets or liabilities or hedged investments, on the condensed consolidated statements of income. The Company may also use financial instruments designated as net investment hedges for accounting purposes to hedge net investments in international subsidiaries whose functional currency is not U.S. dollars. The gain or loss from revaluing accounting hedges of net investments in foreign operations at the spot rate is deferred and reported within accumulated other comprehensive income on the condensed consolidated statements of financial condition. The Company reassesses the effectiveness of its net investment hedge on a quarterly basis. Money Market Fee Waivers . The Company may voluntarily waive a portion of its management fees on certain money market funds to ensure that they maintain a targeted level of daily net investment income (the “Yield Support waivers”). During the three months ended March 31, 2018 and 2017, waivers that resulted in a reduction of management fees were immaterial. BlackRock may increase or decrease the level of Yield Support waivers in future periods. Separate Account Assets and Liabilities . Separate account assets are maintained by BlackRock Life Limited, a wholly owned subsidiary of the Company, which is a registered life insurance company in the United Kingdom, and represent segregated assets held for purposes of funding individual and group pension contracts. The life insurance company does not underwrite any insurance contracts that involve any insurance risk transfer from the insured to the life insurance company. The separate account assets primarily include equity securities, debt securities, money market funds and derivatives. The separate account assets are not subject to general claims of the creditors of BlackRock. These separate account assets and the related equal and offsetting liabilities are recorded as separate account assets and separate account liabilities on the condensed consolidated statements of financial condition. The net investment income attributable to separate account assets supporting individual and group pension contracts accrues directly to the contract owner and is not reported on the condensed consolidated statements of income. While BlackRock has no economic interest in these separate account assets and liabilities, BlackRock earns policy administration and management fees associated with these products, which are included in investment advisory, administration fees and securities lending revenue on the condensed consolidated statements of income. Separate Account Collateral Assets Held and Liabilities Under Securities Lending Agreements. The Company facilitates securities lending arrangements whereby securities held by separate accounts maintained by BlackRock Life Limited are lent to third parties under global master securities lending agreements. In exchange, the Company receives legal title to the collateral with minimum values generally ranging from approximately 102% to 112% of the value of the securities lent in order to reduce counterparty risk. The required collateral value is calculated on a daily basis. The global master securities lending agreements provide the Company the right to request additional collateral or, in the event of borrower default, the right to liquidate collateral. The securities lending transactions entered into by the Company are accompanied by an agreement that entitles the Company to request the borrower to return the securities at any time; therefore, these transactions are not reported as sales. The Company records on the condensed consolidated statements of financial condition the cash and noncash collateral received under these BlackRock Life Limited securities lending arrangements as its own asset in addition to an equal and offsetting collateral liability for the obligation to return the collateral. The securities lending revenue earned from lending securities held by the separate accounts is included in investment advisory, administration fees and securities lending revenue on the condensed consolidated statements of income. During the three months ended March 31, 2018 and 2017, the Company had not resold or repledged any of the collateral received under these arrangements. At March 31, 2018 and December 31, 2017, the fair value of loaned securities held by separate accounts was approximately $24.8 billion and $22.3 billion, respectively, and the fair value of the collateral held under these securities lending agreements was approximately $27.2 billion and $24.2 billion, respectively. Recent Accounting Pronouncements Not Yet Adopted. Leases. In February 2016, the FASB issued ASU 2016-02, (“ASU 2016-02”), which requires lessees to recognize assets and liabilities arising from most operating leases on the condensed consolidated statements of financial condition. The Company expects to record assets and liabilities for its current operating leases upon adoption of ASU 2016-02 and does not expect the adoption to have a material impact on its results of operations or cash flows. ASU 2016-02 is effective for the Company on January 1, 2019, and the Company intends to apply the practical expedients allowed by the standard upon transition. See Note 13 of the 2017 Form 10-K for information on the Company’s operating lease commitments.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	3 Months Ended
	Mar. 31, 2018
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	3. Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash and cash equivalents reported within the condensed consolidated statements of financial condition to the cash, cash equivalents, and restricted cash reported within the condensed consolidated statements of cash flows. March 31, December 31, (in millions) 2018 2017 Cash and cash equivalents $ 5,978 $ 6,894 Cash and cash equivalents of consolidated VIEs 103 144 Restricted cash included in Other assets 62 58 Total cash, cash equivalents and restricted cash $ 6,143 $ 7,096

Investments

Investments	3 Months Ended
	Mar. 31, 2018
Investments Debt And Equity Securities [Abstract]
Investments	4. Investments A summary of the carrying value of total investments is as follows: March 31, (in millions) 2018 (1) Debt securities: Available-for-sale investments $ 151 Held-to-maturity investments 132 Trading securities ($266 debt securities of consolidated sponsored investment funds) 293 Total debt securities 576 Equity securities at FVTNI ($284 equity securities of consolidated sponsored investment funds) 648 Equity method investments (2) 703 Federal Reserve Bank stock (3) 91 Carried interest (4) 32 Total investments $ 2,050 (in millions) December 31, 2017 (1) Available-for-sale investments $ 103 Held-to-maturity investments 102 Trading investments: Consolidated sponsored investment funds: Debt securities 267 Equity securities 245 Other equity and debt securities 267 Deferred compensation plan mutual funds 56 Total trading investments 835 Equity method investments (2) 816 Cost method investments (3) 93 Carried interest (4) 32 Total investments $ 1,981 (1) Amounts at March 31, 2018 reflect the adoption of ASU 2016-01. See Note 2, Significant Accounting Policies (2) Equity method investments primarily include BlackRock’s direct investments in certain BlackRock sponsored investment funds. (3) Amounts include Federal Reserve Bank stock, which is held for regulatory purposes and is restricted from sale. At December 31, 2017, amount also includes other nonmarketable securities, which were immaterial. At March 31, 2018 and December 31, 2017, there were no indicators of impairment on these investments. (4) Carried interest of consolidated sponsor investment funds accounted for as voting rights entities (“VREs”) represents allocations to BlackRock’s general partner capital accounts from certain funds. These balances are subject to change upon cash distributions, additional allocations or reallocations back to limited partners within the respective funds. Available-for-Sale Investments At both March 31, 2018 and December 31, 2017, available-for-sale investments primarily included certain investments in CLOs. The cost of these investments approximated carrying value. Held-to-Maturity Investments The carrying value of held-to-maturity investments was $132 million and $102 million at March 31, 2018 and December 31, 2017, respectively. Held-to-maturity investments included foreign government debt held primarily for regulatory purposes and certain investments in CLOs. The amortized cost (carrying value) of these investments approximated fair value. At March 31, 2018, $12 million of these investments mature between five to Equity and Trading Debt Securities A summary of the cost and carrying value of equity and trading debt securities is as follows: March 31, 2018 (1) (in millions) Cost Carrying Value Trading debt securities: Corporate debt $ 166 $ 169 Government debt 62 62 Asset/mortgage-backed debt 62 62 Equity securities at FVTNI: Equity securities/multi-asset mutual funds 577 614 Deferred compensation plan mutual funds 21 34 Total equity and trading debt securities $ 888 $ 941 December 31, 2017 (1) (in millions) Cost Carrying Value Trading investments: Deferred compensation plan mutual funds $ 34 $ 56 Equity securities/multi-asset mutual funds 446 493 Debt securities Corporate debt 152 157 Government debt 72 73 Asset/mortgage backed debt 56 56 Total trading investments $ 760 $ 835 (1) Amounts at March 31, 2018 reflect the adoption of ASU 2016-01. See Note 2, Significant Accounting Policies Other In addition, the Company accounts for its interest in PennyMac Financial Services, Inc. (“PennyMac”) as an equity method investment. At March 31, 2018 and December 31, 2017 the Company’s investment in PennyMac was excluded from investments in the table above and included in other assets on the condensed consolidated statements of financial condition. The carrying value and fair value of the Company’s interest (approximately 20% or 16 million shares and units) was approximately $363 million and $352 million, respectively, at March 31, 2018 and approximately $342 million and $348 million, respectively, at December 31, 2017. The fair value of the Company’s interest reflected the PennyMac stock price at March 31, 2018 and December 31, 2017, respectively (a Level 1 input). The fair value of the Company’s interest in the non-public units held of PennyMac is based on the stock price of the PennyMac public securities at March 31, 2018 and December 31, 2017.

Consolidated Voting Rights Enti

Consolidated Voting Rights Entities	3 Months Ended
	Mar. 31, 2018
Text Block [Abstract]
Consolidated Voting Rights Entities	5. Consolidated Voting Rights Entities The Company consolidates certain sponsored investment funds accounted for as VREs because it is deemed to control such funds. The following table presents the balances related to these consolidated VREs that were recorded on the condensed consolidated statements of financial condition, including BlackRock’s net interest in these funds: March 31, December 31, (in millions) 2018 2017 Cash and cash equivalents $ 44 $ 63 Investments: Trading debt securities 266 267 Equity securities at FVTNI 284 245 Total investments 550 512 Other assets 15 13 Other liabilities (42 ) (37 ) Noncontrolling interests ("NCI") (87 ) (91 ) BlackRock’s net interests in consolidated VREs $ 480 $ 460 BlackRock’s total exposure to consolidated VREs represents the value of its economic ownership interest in these sponsored investment funds. Valuation changes associated with investments held at fair value by these consolidated VREs are reflected in nonoperating income (expense) and partially offset in net income (loss) attributable to noncontrolling interests for the portion not attributable to BlackRock. The Company cannot readily access cash and cash equivalents held by consolidated VREs to use in its operating activities.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Variable Interest Entities	6. Variable Interest Entities In the normal course of business, the Company is the manager of various types of sponsored investment vehicles, which may be considered variable interest entities (“VIEs”). The Company may from time to time own equity or debt securities or enter into derivatives with the vehicles, each of which are considered variable interests. The Company’s involvement in financing the operations of the VIEs is generally limited to its investments in the entity. The Company consolidates entities when it is determined to be the PB. Consolidated VIEs. The Company’s consolidated VIEs include certain sponsored investment funds in which BlackRock has an investment and as the investment manager is deemed to have both the power to direct the most significant activities of the funds and the right to receive benefits (or the obligation to absorb losses) that could potentially be significant to these sponsored investment funds. The assets of these VIEs are not available to creditors of the Company. In addition, the investors in these VIEs have no recourse to the credit of the Company. Consolidated VIE assets and liabilities are presented after intercompany eliminations in the following table: March 31, December 31, (in millions) 2018 2017 Assets of consolidated VIEs: Cash and cash equivalents $ 103 $ 144 Investments: Trading debt securities 769 475 Equity securities at FVTNI 295 440 Other investments 300 312 Carried interest 273 266 Other assets 113 66 Total investments and other assets 1,750 1,559 Liabilities of consolidated VIEs (425 ) (369 ) Noncontrolling interests (518 ) (375 ) BlackRock's net interests in consolidated VIEs $ 910 $ 959 Net gain (loss) related to consolidated VIEs is presented in the following table: Three Months Ended March 31, (in millions) 2018 2017 Nonoperating net gain (loss) on consolidated VIEs $ 2 $ 33 Net income (loss) attributable to NCI on consolidated VIEs $ 5 $ 8 Non-Consolidated VIEs . At March 31, 2018 and December 31, 2017, the Company’s carrying value of assets and liabilities included on the condensed consolidated statements of financial condition pertaining to nonconsolidated VIEs and its maximum risk of loss related to VIEs for which it held a variable interest, but for which it was not the PB, was as follows: (in millions) At March 31, 2018 Investments Advisory Fee Receivables Other Net Assets (Liabilities) Maximum Risk of Loss (1) Sponsored investment products $ 342 $ 30 $ (7 ) $ 389 At December 31, 2017 Sponsored investment products $ 263 $ 15 $ (7 ) $ 295 (1) At both March 31, 2018 and December 31, 2017, BlackRock’s maximum risk of loss associated with these VIEs primarily related to BlackRock’s investments and the collection of advisory fee receivables. The net assets of sponsored investment products that are nonconsolidated VIEs approximated $6 billion and $5 billion at March 31, 2018 and December 31, 2017, respectively.

Fair Value Disclosures

Fair Value Disclosures	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Disclosures	7. Fair Value Disclosures Fair Value Hierarchy Assets and liabilities measured at fair value on a recurring basis and other assets not held at fair value March 31, 2018 (1) (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV (2) Other Assets Not Held at Fair Value (3) March 31, 2018 Assets: Investments: Equity securities at FVTNI: Deferred compensation plan mutual funds $ 34 $ — $ — $ — $ — $ 34 Equity securities/Multi-asset mutual funds 614 — — — — 614 Total equity securities 648 — — — — 648 Debt securities: Available-for-sale — 125 26 — — 151 Trading securities — 288 5 — — 293 Held-to-maturity securities — — — — 132 132 Total debt securities — 413 31 — 132 576 Equity method: Equity and fixed income mutual funds 116 — — 15 — 131 Other — — — 569 3 572 Total equity method 116 — — 584 3 703 Federal Reserve Bank Stock — — — — 91 91 Carried interest — — — — 32 32 Total investments 764 413 31 584 258 2,050 Investments of consolidated VIEs: Equity securities 295 — — — — 295 Trading debt securities — 769 — — — 769 Private / public equity (4) 3 3 116 56 72 250 Other — — — 50 — 50 Carried interest — — — — 273 273 Total investments of consolidated VIEs 298 772 116 106 345 1,637 Other assets (5) — 35 — — — 35 Separate account assets 107,095 35,063 — — 712 142,871 Separate account collateral held under securities lending agreements: Equity securities 18,543 — — — — 18,543 Debt securities — 8,704 — — — 8,704 Total separate account collateral held under securities lending agreements 18,543 8,704 — — — 27,247 Total $ 126,700 $ 44,987 $ 147 $ 690 $ 1,315 $ 173,840 Liabilities: Separate account collateral liabilities under securities lending agreements $ 18,543 $ 8,704 $ — $ — $ — $ 27,247 Other liabilities (6) — 7 242 — — 249 Total $ 18,543 $ 8,711 $ 242 $ — $ — $ 27,496 (1) Significant Accounting Policies (2) Amounts are comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. (3) Amounts are comprised of investments held at cost or amortized cost, carried interest and certain equity method investments, which include sponsored investment funds and other assets, which are not accounted for under a fair value measure. In accordance with GAAP, certain equity method investees do not account for both their financial assets and liabilities under fair value measures; therefore, the Company’s investment in such equity method investees may not represent fair value. (4) Level 3 amounts primarily include direct investments in private equity companies held by private equity funds. (5) Amounts include fair value of forward foreign currency exchange contracts (see Note 8, Derivatives and Hedging (6) Amounts primarily include contingent liabilities related to certain acquisitions (see Note 12, Commitments and Contingencies Assets and liabilities measured at fair value on a recurring basis and other assets not held at fair value December 31, 2017 (1) (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV (2) Other Assets Not Held at Fair Value (3) December 31, 2017 Assets: Investments Available-for-sale $ 7 $ 96 $ — $ — $ — $ 103 Held-to-maturity debt securities — — — — 102 102 Trading: Deferred compensation plan mutual funds 56 — — — — 56 Equity/Multi-asset mutual funds 493 — — — — 493 Debt securities / fixed income mutual funds 2 284 — — — 286 Total trading 551 284 — — — 835 Equity method: Equity and fixed income mutual funds 183 — — 12 — 195 Other — — — 609 12 621 Total equity method 183 — — 621 12 816 Cost method investments — — — — 93 93 Carried interest — — — — 32 32 Total investments 741 380 — 621 239 1,981 Separate account assets 114,422 34,582 — — 933 149,937 Separate account collateral held under securities lending agreements: Equity securities 18,778 — — — — 18,778 Debt securities — 5,412 — — — 5,412 Total separate account collateral held under securities lending agreements 18,778 5,412 — — — 24,190 Investments of consolidated VIEs: Trading: Equity securities 440 — — — — 440 Debt securities — 475 — — — 475 Private / public equity (4) 6 2 116 59 76 259 Other — — — 53 — 53 Carried interest — — — — 266 266 Total investments of consolidated VIEs 446 477 116 112 342 1,493 Total $ 134,387 $ 40,851 $ 116 $ 733 $ 1,514 $ 177,601 Liabilities: Separate account collateral liabilities under securities lending agreements $ 18,778 $ 5,412 $ — $ — $ — $ 24,190 Other liabilities (5) — 7 236 — — 243 Total $ 18,778 $ 5,419 $ 236 $ — $ — $ 24,433 (1) Amounts at December 31, 2017 reflect accounting guidance prior to ASU 2016-01. (2) Amounts are comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. (3) Amounts are comprised of investments held at cost or amortized cost, carried interest and certain equity method investments, which include sponsored investment funds and other assets, which are not accounted for under a fair value measure. In accordance with GAAP, certain equity method investees do not account for both their financial assets and liabilities under fair value measures; therefore, the Company’s investment in such equity method investees may not represent fair value. (4) Level 3 amounts include direct investments in private equity companies held by private equity funds. (5) Amounts primarily include contingent liabilities related to certain acquisitions (see Note 12, Commitments and Contingencies Level 3 Assets. Level 3 investments of consolidated VIEs of $116 million at both March 31, 2018 and December 31, 2017, related to direct investments in private equity companies held by consolidated private equity funds. Direct investments in private equity companies may be valued using the market approach or the income approach, or a combination thereof, and were valued based on an assessment of each underlying investment, incorporating evaluation of additional significant third-party financing, changes in valuations of comparable peer companies, the business environment of the companies, market indices, assumptions relating to appropriate risk adjustments for nonperformance and legal restrictions on disposition, among other factors. The fair value derived from the methods used is evaluated and weighted, as appropriate, considering the reasonableness of the range of values indicated. Under the market approach, fair value may be determined by reference to multiples of market-comparable companies or transactions, including earnings before interest, taxes, depreciation and amortization (“EBITDA”) multiples. Under the income approach, fair value may be determined by discounting the expected cash flows to a single present value amount using current expectations about those future amounts. Unobservable inputs used in a discounted cash flow model may include projections of operating performance generally covering a five-year period and a terminal value of the private equity direct investment. For investments utilizing the discounted cash flow valuation technique, a significant increase (decrease) in the discount rate, risk premium or discount for lack of marketability in isolation could result in a significantly lower (higher) fair value measurement. For investments utilizing the market-comparable valuation technique, a significant increase (decrease) in the EBITDA multiple in isolation could result in a significantly higher (lower) fair value measurement. Level 3 assets may include investments in CLOs valued based on single-broker nonbinding quotes and direct private equity investments valued using the market approach or the income approach as described above. Level 3 Liabilities. Level 3 other liabilities primarily include recorded contingent liabilities related to certain acquisitions, which were valued based upon discounted cash flow analyses using unobservable market data inputs. Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis for the Three Months Ended March 31, 2018 (in millions) December 31, 2017 Realized and Unrealized Gains (Losses) in Earnings and OCI Purchases Sales and Maturities Issuances and other Settlements Transfers into Level 3 Transfers out of Level 3 March 31, 2018 (1) Total Net Unrealized Gains (Losses) Included in Earnings (2) Assets: Investments: Debt securities: Available-for-sale securities (3) $ — $ — $ 26 $ — $ — $ — $ — $ 26 Trading securities — — 5 — — — — 5 Total investments — — 31 — — — — 31 Assets of consolidated VIEs - Private equity 116 — — — — — — 116 Total Level 3 assets $ 116 $ — $ 31 $ — $ — $ — $ — $ 147 Liabilities: Other liabilities (4) $ 236 (6 ) $ — $ — $ — $ — $ — $ 242 $ (6 ) (1) Amounts at March 31, 2018 reflect the adoption of ASU 2016-01. See Note 2, Significant Accounting Policies (2) Earnings attributable to the change in unrealized gains (losses) relating to assets and liabilities still held at the reporting date. (3) Amounts include investments in CLOs. (4) Other liabilities amount includes contingent liabilities in connection with certain acquisitions. Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis for the Three Months Ended March 31, 2017 (1) (in millions) December 31, 2016 Realized and Unrealized Gains (Losses) in Earnings and OCI Purchases Sales and Maturities Issuances and other Settlements Transfers into Level 3 Transfers out of Level 3 (2) March 31, 2017 Total Net Unrealized Gains (Losses) Included in Earnings (3) Assets: Investments: Available-for-sale securities (4) $ 24 $ — $ — $ — $ — $ — $ (24 ) $ — Trading 7 — — — — — (7 ) — Total investments 31 — — — — — (31 ) — Assets of consolidated VIEs - Private equity 112 1 — — — — — 113 $ 1 Total Level 3 assets $ 143 $ 1 $ — $ — $ — $ — $ (31 ) $ 113 Liabilities: Other liabilities (5) $ 115 $ 2 $ — $ — $ — $ — $ — $ 113 $ 2 (1) Amounts at March 31, 2017 reflect accounting guidance prior to ASU 2016-01. (2) Amounts include transfers out of Level 3 due to availability of observable market inputs from pricing vendors. (3) Earnings attributable to the change in unrealized gains (losses) relating to assets and liabilities still held at the reporting date. (4) Amounts include investments in CLOs. (5) Other liabilities amount includes contingent liabilities in connection with certain acquisitions. Realized and Unrealized Gains (Losses) for Level 3 Assets and Liabilities. Realized and unrealized gains (losses) recorded for Level 3 assets and liabilities are reported in nonoperating income (expense) on the condensed consolidated statements of income. A portion of net income (loss) for consolidated sponsored investment funds is allocated to noncontrolling interests to reflect net income (loss) not attributable to the Company. Transfers in and/or out of Levels. Transfers in and/or out of levels are reflected when significant inputs, including market inputs or performance attributes, used for the fair value measurement become observable/unobservable, or when the carrying value of certain equity method investments no longer represents fair value as determined under valuation methodologies. Disclosures of Fair Value for Financial Instruments Not Held at Fair Value . At March 31, 2018 and December 31, 2017, the fair value of the Company’s financial instruments not held at fair value are categorized in the table below: March 31, 2018 December 31, 2017 (in millions) Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Fair Value Hierarchy Financial Assets: Cash and cash equivalents $ 5,978 $ 5,978 $ 6,894 $ 6,894 Level 1 (1) (2) Cash and cash equivalents of consolidated VIEs 103 103 144 144 Level 1 (1) (2) Other assets 62 62 70 70 Level 1 (1) (3) Financial Liability: Long-term borrowings 5,036 5,134 5,014 5,225 Level 2 (4) (1) Cash and cash equivalents are carried at either cost or amortized cost, which approximates fair value due to their short-term maturities. (2) At March 31, 2018 and December 31, 2017, approximately $204 million and $163 million, respectively, of money market funds were recorded within cash and cash equivalents on the condensed consolidated statements of financial condition. In addition, at March 31, 2018 and December 31, 2017, approximately $13 million and $14 million, respectively, of money market funds were recorded within cash and cash equivalents of consolidated VIEs. Money market funds are valued based on quoted market prices, or $1.00 per share, which generally is the NAV of the fund. (3) Other assets primarily include restricted cash. (4) Long-term borrowings are recorded at amortized cost net of debt issuance costs. The fair value of the long-term borrowings, including the current portion of long-term borrowings, is estimated using market prices at the end of March 2018 and December 2017, respectively. See Note 11, Borrowings Investments in Certain Entities that Calculate Net Asset Value Per Share As a practical expedient to value certain investments that do not have a readily determinable fair value and have attributes of an investment company, the Company uses NAV as the fair value. The following tables list information regarding all investments that use a fair value measurement to account for both their financial assets and financial liabilities in their calculation of a NAV per share (or equivalent). March 31, 2018 (in millions) Ref Fair Value Total Unfunded Commitments Redemption Frequency Redemption Notice Period Equity method: (1) Hedge funds/funds of hedge funds (a) $ 168 $ 64 Daily/Monthly (30%) Quarterly (29%) N/R (41%) 1 – 90 days Private equity funds (b) 99 85 N/R N/R Real assets funds (c) 302 79 Quarterly (78%) N/R (22%) 60 days Other 15 15 Daily/Monthly (79%) N/R (21%) 3 – 5 days Consolidated VIEs: Private equity funds of funds (d) 56 18 N/R N/R Hedge fund (a) 14 — Quarterly 90 days Real assets funds (c) 36 48 N/R N/R Total $ 690 $ 309 December 31, 2017 (in millions) Ref Fair Value Total Unfunded Commitments Redemption Frequency Redemption Notice Period Equity method: (1) Hedge funds/funds of hedge funds (a) $ 230 $ 48 Daily/Monthly (21%) Quarterly (49%) N/R (30%) 1 – 90 days Private equity funds (b) 94 86 N/R N/R Real assets funds (c) 282 69 Quarterly (83%) N/R (17%) 60 days Other 15 14 Daily (80%) N/R (20%) 5 days Consolidated VIEs: Private equity funds of funds (d) 59 20 N/R N/R Hedge fund (a) 19 — Quarterly 90 days Real assets funds (c) 34 49 N/R N/R Total $ 733 $ 286 N/R – not redeemable (1) Comprised of equity method investments, which include investment companies, which account for their financial assets and most financial liabilities under fair value measures; therefore, the Company’s investment in such equity method investees approximates fair value. (a) This category includes hedge funds and funds of hedge funds that invest primarily in equities, fixed income securities, distressed credit, opportunistic and mortgage instruments and other third-party hedge funds. The fair values of the investments have been estimated using the NAV of the Company’s ownership interest in partners’ capital. It was estimated that the investments in the funds that are not subject to redemption will be liquidated over a weighted-average period of seven years at both March 31, 2018 and December 31, 2017. (b) This category includes several private equity funds that initially invest in nonmarketable securities of private companies, which ultimately may become public in the future. The fair values of these investments have been estimated using capital accounts representing the Company’s ownership interest in the funds as well as other performance inputs. The Company’s investment in each fund is not subject to redemption and is normally returned through distributions as a result of the liquidation of the underlying assets of the private equity funds. It was estimated that the investments in these funds will be liquidated over a weighted-average period of approximately six years at both March 31, 2018 and December 31, 2017. (c) This category includes several real assets funds that invest directly and indirectly in real estate and infrastructure. The fair values of the investments have been estimated using capital accounts representing the Company’s ownership interest in the funds. The Company’s investments that are not subject to redemption or are not currently redeemable are normally returned through distributions and realizations of the underlying assets of the funds. It is estimated that the investments in these funds not subject to redemptions will be liquidated over a weighted-average period of approximately eight years at both March 31, 2018 and December 31, 2017. The total remaining unfunded commitments to real assets funds were $128 million and $117 million at March 31, 2018 and December 31, 2017, respectively. The Company had contractual obligations to the real assets funds of $108 million at March 31, 2018 and $98 million at December 31, 2017. (d)

Derivatives and Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	8. Derivatives and Hedging The Company maintains a program to enter into swaps to hedge against market price and interest rate exposures with respect to certain seed investments in sponsored investment products. At March 31, 2018, the Company had outstanding total return swaps with an aggregate notional value of approximately $546 million. At December 31, 2017, the Company had outstanding total return swaps with an aggregate notional value of approximately $587 million. Gains (losses) on total return swaps recorded in nonoperating income (expense) were not material for the three months ended March 31, 2018 and were $(35) million for the three months ended March 31, 2017. Gains (losses) on interest rate swaps are recorded in nonoperating income (expense) and were not material for the three months ended March 31, 2018 and 2017. At both March 31, 2018 and December 31, 2017, the Company had a derivative providing credit protection of approximately $17 million to a counterparty, representing the Company’s maximum risk of loss with respect to the provision of credit protection. The Company carries the derivative at fair value based on the expected discounted future cash outflows under the arrangement. The Company executes forward foreign currency exchange contracts to mitigate the risk of certain foreign exchange movements. At both March 31, 2018 and December 31, 2017, the Company had outstanding forward foreign currency exchange contracts with aggregate notional values of approximately $1.5 billion. The fair value of the outstanding forward foreign currency exchange contracts was $35 million at March 31, 2018 and was not material at December 31, 2017. Gains (losses) on the forward foreign currency exchange contracts are recorded in other general and administration expense and were $30 million for the three months ended March 31, 2018. Gains (losses) on the forward foreign currency exchange contracts were not material for the three months ended March 31, 2017. The Company consolidates certain sponsored investment funds, which may utilize derivative instruments as a part of the funds’ investment strategies. The change in fair value of such derivatives, which is recorded in nonoperating income (expense), was not material for the three months ended March 31, 2018 and 2017. The fair values of the outstanding total return swaps and the credit default swap were not material to the condensed consolidated statement of financial condition at March 31, 2018. The fair value of the outstanding derivatives mentioned above was not material to the condensed consolidated statement of financial condition at December 31, 2017. See Note 12, Borrowings

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	9. Goodwill Goodwill activity during the three months ended March 31, 2018 was as follows: (in millions) December 31, 2017 $ 13,220 Goodwill adjustments related to Quellos (1) (3 ) March 31, 2018 $ 13,217 (1) The decrease in goodwill during the three months ended March 31, 2018 resulted from a decline related to tax benefits realized from tax-deductible goodwill in excess of book goodwill from the acquisition of the fund-of-funds business of Quellos Group, LLC in October 2007 (the “Quellos Transaction”). Goodwill related to the Quellos Transaction will continue to be reduced in future periods by the amount of tax benefits realized from tax-deductible goodwill in excess of book goodwill from the Quellos Transaction. The balance of the Quellos tax-deductible goodwill in excess of book goodwill was approximately $161 million and $168 million at March 31, 2018 and December 31, 2017, respectively.

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	10. Intangible Assets The carrying amounts of identifiable intangible assets are summarized as follows: (in millions) Indefinite-lived Finite-lived Total December 31, 2017 $ 17,178 $ 211 $ 17,389 Amortization expense — (11 ) (11 ) March 31, 2018 $ 17,178 $ 200 $ 17,378

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Borrowings	11. Borrowings Short-Term Borrowings 2018 Revolving Credit Facility. The Company’s credit facility has an aggregate commitment amount of $4.0 billion and was amended in April 2018 to extend the maturity date to March 2023 (the “2018 credit facility”). The 2018 credit facility permits the Company to request up to an additional $1.0 billion of borrowing capacity, subject to lender credit approval, increasing the overall size of the 2018 credit facility to an aggregate principal amount not to exceed $5.0 billion. Interest on borrowings outstanding accrues at a rate based on the applicable London Interbank Offered Rate plus a spread. The 2018 credit facility requires the Company not to exceed a maximum 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 to 1, which was satisfied with a ratio of less than 1 to 1 at March 31, 2018. The 2018 credit facility provides back-up liquidity to fund ongoing working capital for general corporate purposes and various investment opportunities. At March 31, 2018, the Company had no amount outstanding under the credit facility. Commercial Paper Program. The Company can issue unsecured commercial paper notes (the “CP Notes”) on a private-placement basis up to a maximum aggregate amount outstanding at any time of $4.0 billion. The commercial paper program is currently supported by the 2018 credit facility. At March 31, 2018, BlackRock had no CP Notes outstanding. Long-Term Borrowings The carrying value and fair value of long-term borrowings estimated using market prices and foreign exchange rates at March 31, 2018 included the following: (in millions) Maturity Amount Unamortized Discount and Debt Issuance Costs Carrying Value Fair Value 5.00% Notes due 2019 $ 1,000 $ — $ 1,000 $ 1,039 4.25% Notes due 2021 750 (2 ) 748 774 3.375% Notes due 2022 750 (4 ) 746 759 3.50% Notes due 2024 1,000 (6 ) 994 1,006 1.25% Notes due 2025 861 (6 ) 855 877 3.20% Notes due 2027 700 (7 ) 693 679 Total Long-term Borrowings $ 5,061 $ (25 ) $ 5,036 $ 5,134 See Note 12, Borrowings

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Investment Commitments. At March 31, 2018, the Company had $304 million of various capital commitments to fund sponsored investment funds, including consolidated VIEs. These funds include private equity funds, real assets funds and opportunistic funds. This amount excludes additional commitments made by consolidated funds of funds to underlying third-party funds as third-party noncontrolling interest holders have the legal obligation to fund the respective commitments of such funds of funds. Generally, the timing of the funding of these commitments is unknown and the commitments are callable on demand at any time prior to the expiration of the commitment. These unfunded commitments are not recorded on the condensed consolidated statements of financial condition. These commitments do not include potential future commitments approved by the Company that are not yet legally binding. The Company intends to make additional capital commitments from time to time to fund additional investment products for, and with, its clients. Lease Commitment. In May 2017, the Company entered into an agreement with 50 HYMC Owner LLC, for the lease of approximately 847,000 square feet of office space located at 50 Hudson Yards, New York, New York. The term of the lease is twenty years from the date that rental payments begin, expected to occur in May 2023, with the option to renew for a specified term. The lease requires annual base rental payments of approximately $51 million per year during the first five years of the lease term, increasing every five years to $58 million, $66 million and $74 million per year (or approximately $1.2 billion in base rent over its twenty-year term). Contingencies Contingent Payments Related to Business Acquisitions . In connection with certain acquisitions, BlackRock is required to make contingent payments, subject to achieving specified performance targets, which may include revenue related to acquired contracts or new capital commitments for certain products. The fair value of the remaining aggregate contingent payments at March 31, 2018 totaled $242 million, and is included in other liabilities on the condensed consolidated statements of financial condition. Other Contingent Payments. The Company acts as the portfolio manager in a derivative transaction and has a maximum potential exposure of $17 million between the Company and counterparty. See Note 8, , for further discussion. Legal Proceedings. From time to time, BlackRock receives subpoenas or other requests for information from various U.S. federal, state governmental and regulatory authorities and international regulatory authorities in connection with industry-wide or other investigations or proceedings. It is BlackRock’s policy to cooperate fully with such inquiries. The Company and certain of its subsidiaries have been named as defendants in various legal actions, including arbitrations and other litigation arising in connection with BlackRock’s activities. Additionally, BlackRock-advised investment portfolios may be subject to lawsuits, any of which potentially could harm the investment returns of the applicable portfolio or result in the Company being liable to the portfolios for any resulting damages. On May 27, 2014, certain investors in the BlackRock Global Allocation Fund, Inc. and the BlackRock Equity Dividend Fund (collectively, the “Funds”) filed a consolidated complaint (the “Consolidated Complaint”) in the U.S. District Court for the District of New Jersey against BlackRock Advisors, LLC, BlackRock Investment Management, LLC and BlackRock International Limited under the caption In re BlackRock Mutual Funds Advisory Fee Litigation In November 2015, BlackRock, Inc., BlackRock Realty Advisors, Inc. (“BRA”), BlackRock US Core Property Fund, Inc. (formerly known as BlackRock Granite Property Fund, Inc.) (“Granite Fund”), and certain other Granite Fund related entities (collectively, the “BlackRock Parties”) were named as defendants in thirteen lawsuits filed in the Superior Court of the State of California for the County of Alameda arising out of the June 16, 2015 collapse of a balcony at the Library Gardens apartment complex in Berkeley, California (the “Property”). The Property is indirectly owned by the Granite Fund, which is managed by BRA. The plaintiffs also named as defendants in the lawsuits Greystar, which manages the Property, and certain other non-BlackRock related entities, including the developer of the Property, building contractors and building materials suppliers. The plaintiffs alleged, among other things, that the BlackRock Parties were negligent in their ownership, control and maintenance of the Property’s balcony, and sought monetary, including punitive, damages. Additionally, on March 16, 2016, three former tenants of the Library Gardens apartment unit who were not physically injured but experienced the balcony collapse sued the BlackRock Parties for emotional damages. In November 2017, the BlackRock Parties settled all of the lawsuits relating to Library Gardens and the cases were formally dismissed in March and April 2018. On June 16, 2016, iShares iShares iShares On April 5, 2017, BlackRock, Inc., BlackRock Institutional Trust Company, N.A. (“BTC”), the BlackRock, Inc. Retirement Committee and various sub-committees, and a BlackRock employee were named as defendants in a purported class action lawsuit brought in the U.S. District Court for the Northern District of California by a former employee on behalf of all BlackRock employee 401(k) Plan (the “Plan”) participants and beneficiaries in the Plan from April 5, 2011, to the present. The lawsuit generally alleges that the defendants breached their duties towards Plan participants in violation of the Employee Retirement Income Security Act of 1974 by, among other things, offering investment options that were overly expensive, underperformed peer funds, focused disproportionately on active versus passive strategies, and were unduly concentrated with investment options managed by BlackRock. While the complaint does not contain any specific amount in alleged damages, it claims that the purported underperformance and hidden fees cost Plan participants more than $60 million. On October 10, 2017, the plaintiffs filed an Amended Complaint, which, among other things, adds as defendants certain current and former members of the BlackRock Retirement and Investment Committees. The Amended Complaint also includes a new purported class claim on behalf of investors in certain Collective Trust Funds (“CTFs”) managed by BTC. Specifically, the plaintiffs allege that BTC, as fiduciary to the CTFs, engaged in self-dealing by, most significantly, selecting itself as the lending agent on terms that plaintiffs claim were excessive. The defendants believe the claims in this lawsuit are without merit and are vigorously defending the action. BlackRock moved to dismiss the Amended Complaint on November 8, 2017. Management, after consultation with legal counsel, currently does not anticipate that the aggregate liability arising out of regulatory matters or lawsuits will have a material effect on BlackRock’s results of operations, financial position, or cash flows. However, there is no assurance as to whether any such pending or threatened matters will have a material effect on BlackRock’s results of operations, financial position or cash flows in any future reporting period. Due to uncertainties surrounding the outcome of these matters, management cannot reasonably estimate the possible loss or range of loss that may arise from these matters. Indemnifications. In the ordinary course of business or in connection with certain acquisition agreements, BlackRock enters into contracts pursuant to which it may agree to indemnify third parties in certain circumstances. The terms of these indemnities vary from contract to contract and the amount of indemnification liability, if any, cannot be determined or the likelihood of any liability is considered remote. Consequently, no liability has been recorded on the condensed consolidated statements of financial condition. In connection with securities lending transactions, BlackRock has issued certain indemnifications to certain securities lending clients against potential loss resulting from a borrower’s failure to fulfill its obligations under the securities lending agreement should the value of the collateral pledged by the borrower at the time of default be insufficient to cover the borrower’s obligation under the securities lending agreement. At March 31, 2018, the Company indemnified certain of its clients for their securities lending loan balances of approximately $219 billion. The Company held, as agent, cash and securities totaling $232 billion as collateral for indemnified securities on loan at March 31, 2018. The fair value of these indemnifications was not material at March 31, 2018.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2018
Revenue From Contract With Customer [Abstract]
Revenue	13. Revenue The table below presents the Company’s revenue for the three months ended March 31, 2018 and 2017, respectively, and disaggregates investment advisory, administration fees and securities lending revenue and performance fees by product type and investment style. See Note 2, Significant Accounting Policies Three Months Ended March 31, (in millions) 2018 2017 Investment advisory, administration fees and securities lending revenue: Equity: Active $ 438 $ 400 iShares ETFs 926 721 Non-ETF index 176 160 Equity subtotal 1,540 1,281 Fixed income: Active 456 407 iShares ETFs 208 185 Non-ETF index 93 85 Fixed income subtotal 757 677 Multi-asset 296 272 Alternatives: Core 178 144 Currency and commodities 25 22 Alternatives subtotal 203 166 Long-term 2,796 2,396 Cash management 151 127 Total base fees 2,947 2,523 Investment advisory performance fees: Equity 18 15 Fixed income 3 10 Multi-asset 5 5 Alternatives 44 40 Total performance fees 70 70 Technology and risk management revenue 184 154 Distribution fees: Retrocessions 192 155 12b-1 fees (U.S. mutual funds distribution fees) 108 122 Other 11 10 Total distribution fees 311 287 Advisory and other revenue Advisory 21 24 Other 50 34 Advisory and other revenue 71 58 Total revenue $ 3,583 $ 3,092 The table below presents the investment advisory, administration fees and securities lending revenue by client type, investment style and product type, respectively: For the Three Months Ended March 31, (in millions) 2018 2017 Investment advisory, administration fees and securities lending revenue by client type: Retail $ 855 $ 776 iShares ETFs 1,158 925 Institutional: Active 527 458 Index 256 237 Total institutional 783 695 Long-term 2,796 2,396 Cash management 151 127 Total $ 2,947 $ 2,523 Investment advisory, administration fees and securities lending revenue by investment style: Active $ 1,365 $ 1,220 Index and iShares 1,431 1,176 Long-term 2,796 2,396 Cash management 151 127 Total $ 2,947 $ 2,523 Investment advisory, administration fees and securities lending revenue by product type: Equity $ 1,540 $ 1,281 Fixed income 757 677 Multi-asset 296 272 Alternatives 203 166 Long-term 2,796 2,396 Cash management 151 127 Total $ 2,947 $ 2,523 Investment advisory and administration fees The table below presents estimated investment advisory and administration fees expected to be recognized in the future related to the unsatisfied portion of the performance obligations at March 31, 2018: Remainder of (in millions) 2018 2019 2020 2021 Thereafter Total Investment advisory and administration fees: Alternatives (1)(2) $ 61 $ 70 $ 58 $ 48 $ 48 $ 285 (1) Investment advisory and administration fees include management fees related to certain alternative products, which are based on contractual committed capital outstanding at March 31, 2018. Actual management fees could be higher to the extent additional committed capital is raised. These fees are generally billed on a quarterly basis in arrears. The Company excludes fees that are probable of significant reversal in future periods. (2) The Company elected the following practical expedients and does not include amounts related to (1) performance obligations with an original duration of one year or less, (2) variable consideration related to future service periods, and (3) the comparative prior period as of March 31, 2017. Investment advisory performance fees / Carried interest The table below presents changes in the deferred carried interest liability (including the portion related to consolidated VIEs) for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, (in millions) 2018 2017 Beginning balance $ 219 $ 152 Net increase (decrease) in unrealized allocations 5 9 Performance fee revenue recognized that was included in the deferred carried interest liability balance at the beginning of the period — (10 ) Ending balance $ 224 $ 151 Technology and risk management revenue The table below presents estimated technology and risk management revenue expected to be recognized in the future related to the unsatisfied portion of the performance obligations at March 31, 2018: Remainder of (in millions) 2018 2019 2020 2021 Thereafter Total Technology and risk management revenue (1)(2) $ 25 $ 24 $ 20 $ 15 $ 10 $ 94 (1) Technology and risk management revenue primarily includes upfront payments from customers, which the Company generally recognizes as services are performed. The Company excludes fees that are probable of significant reversal in future periods. (2) The Company elected the following practical expedients and does not include amounts related to (1) performance obligations with an original duration of one year or less, (2) variable consideration related to future service periods, and (3) the comparative prior period as of March 31, 2017. In addition to amounts disclosed in the table above, certain technology and risk management contracts require fixed minimum fees, which are billed on a monthly or quarterly basis in arrears. The Company recognizes such revenue as services are performed. As of March 31, 2018, the estimated fixed minimum fees for the remainder of 2018 for currently outstanding contracts approximated $348 million. The term for these contracts, which are either in their initial or renewal period, ranges from one to five years. The table below presents changes in the technology and risk management deferred revenue liability for the three months ended March 31, 2018 and 2017, which is included in other liabilities on the condensed consolidated statements of financial condition: Three Months Ended March 31, (in millions) 2018 2017 Beginning balance $ 62 $ 42 Additions 12 8 Amount recognized included in the deferred revenue liability beginning balance (8 ) (4 ) Ending balance $ 66 $ 46

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	14. Stock-Based Compensation Restricted Stock and RSUs. Restricted stock and restricted stock units (“RSUs”) activity for the three months ended March 31, 2018 is summarized below. Outstanding at Restricted Stock and RSUs Weighted- Average Grant Date Fair Value December 31, 2017 2,608,668 $ 342.79 Granted 753,901 $ 565.83 Converted (1,071,338 ) $ 336.95 Forfeited (6,721 ) $ 408.89 March 31, 2018 (1) 2,284,510 $ 418.94 (1) At March 31, 2018, approximately 2.1 million awards are expected to vest and 0.2 million awards have vested but have not been converted. In January 2018, the Company granted 527,337 RSUs or shares of restricted stock to employees as part of 2017 annual incentive compensation that vest ratably over three years from the date of grant and 209,201 RSUs or shares of restricted stock to employees that cliff vest 100% on January 31, 2021. The Company values restricted stock and RSUs at their grant-date fair value as measured by BlackRock’s common stock price. The total fair market value of RSUs/restricted stock granted to employees during the three months ended March 31, 2018 was $427 million. At March 31, 2018, the intrinsic value of outstanding RSUs was $1.2 billion, reflecting a closing stock price of $541.72. At March 31, 2018, total unrecognized stock-based compensation expense related to unvested RSUs was $575 million. The unrecognized compensation cost is expected to be recognized over the remaining weighted-average period of 1.5 years. Performance-Based RSUs. Performance-based RSU activity for the three months ended March 31, 2018 is summarized below. Outstanding at Performance- Based RSUs Weighted- Average Grant Date Fair Value December 31, 2017 903,525 $ 335.12 Granted 199,068 $ 566.44 Additional shares granted due to attainment of performance measures 23,376 $ 343.86 Converted (269,648 ) $ 343.86 March 31, 2018 856,321 $ 386.38 In January 2018, the Company granted 199,068 performance-based RSUs to certain employees that cliff vest 100% on January 31, 2021. These awards are amortized over a service period of three years. The number of shares distributed at vesting could be higher or lower than the original grant based on the level of attainment of predetermined Company performance measures. In January 2018, the Company granted 23,376 performance-based RSUs to certain employees based on the attainment of Company performance measures during the performance period. The Company initially values performance-based RSUs at their grant-date fair value as measured by BlackRock’s common stock price. The total grant-date fair market value of performance-based RSUs granted to employees during the three months ended March 31, 2018 was $121 million. At March 31, 2018, the intrinsic value of outstanding performance-based RSUs was $464 million, reflecting a closing stock price of $541.72. At March 31, 2018, total unrecognized stock-based compensation expense related to unvested performance-based awards was $203 million. The unrecognized compensation cost is expected to be recognized over the remaining weighted-average period of 1.7 years. See Note 14, Stock-Based Compensation, Market Performance-based RSUs. Market performance-based RSUs activity for the three months ended March 31, 2018 is summarized below. Outstanding at Market Performance- Based RSUs Weighted- Average Grant Date Fair Value December 31, 2017 286,336 $ 195.33 Converted (286,336 ) $ 195.33 March 31, 2018 — $ — See Note 14, Stock-Based Compensation, Long-Term Incentive Plans Funded by PNC. Under a share surrender agreement, PNC committed to provide up to 4 million shares of BlackRock stock, held by PNC, to fund certain BlackRock long-term incentive plans (“LTIP”), including performance-based and market performance-based RSUs. The current share surrender agreement commits PNC to provide BlackRock Series C nonvoting participating preferred stock to fund the remaining committed shares. As of March 31, 2018, 3.9 million shares had been surrendered by PNC, including 103,064 shares during the three months ended March 31, 2018. At March 31, 2018, the remaining shares committed by PNC of 0.1 million were available to fund certain future long-term incentive awards. Performance-based Stock Options. Stock option activity for the three months ended March 31, 2018 is summarized below. Outstanding at Shares Under Option Weighted Average Exercise Price December 31, 2017 2,147,562 $ 513.50 Granted — $ — March 31, 2018 2,147,562 $ 513.50 At March 31, 2018, total unrecognized stock-based compensation expense related to unvested performance-based stock options was $191 million. The unrecognized compensation cost is expected to be recognized over the remaining weighted-average period of 5.7 years. See Note 14, Stock-Based Compensation,

Net Capital Requirements

Net Capital Requirements	3 Months Ended
	Mar. 31, 2018
Regulatory Capital Requirements [Abstract]
Net Capital Requirements	15. Net Capital Requirements The Company is required to maintain net capital in certain regulated subsidiaries within a number of jurisdictions, which is partially maintained by retaining cash and cash equivalent investments in those subsidiaries or jurisdictions. As a result, such subsidiaries of the Company may be restricted in their ability to transfer cash between different jurisdictions and to their parents. Additionally, transfers of cash between international jurisdictions may have adverse tax consequences that could discourage such transfers. At March 31, 2018, the Company was required to maintain approximately $2.1 billion in net capital in certain regulated subsidiaries, including BlackRock Institutional Trust Company, N.A. (a wholly owned subsidiary of the Company that is chartered as a national bank whose powers are limited to trust and other fiduciary activities and which is subject to regulatory capital requirements administered by the Office of the Comptroller of the Currency), entities regulated by the Financial Conduct Authority and Prudential Regulation Authority in the United Kingdom, and the Company’s broker-dealers. The Company was in compliance with all applicable regulatory net capital requirements.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	16. Accumulated Other Comprehensive Income (Loss) The following tables present changes in accumulated other comprehensive income (loss) (“AOCI”) by component for the three months ended March 31, 2018 and 2017: (in millions) Foreign currency translation adjustments (1) Other (2) Total For the Three Months Ended March 31, 2018 December 31, 2017 $ (436 ) $ 4 $ (432 ) Net other comprehensive income (loss) for the three months ended March 31, 2018 137 — 137 Reclassification as a result of adoption of ASU 2018-02 (6 ) — (6 ) March 31, 2018 $ (305 ) $ 4 $ (301 ) (1) Amount for the three months ended March 31, 2018 includes a loss from a net investment hedge of $16 million (net of a tax benefit of $5 million) and reclassification as a result of adoption of ASU 2018-02. (2) (in millions) Foreign currency translation adjustments (1) Other (2) Total For the Three Months Ended March 31, 2017 December 31, 2016 $ (721 ) $ 5 $ (716 ) Net other comprehensive income (loss) for the three months ended March 31, 2017 40 (1 ) 39 March 31, 2017 $ (681 ) $ 4 $ (677 ) ( 1) (2)

Capital Stock

Capital Stock	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Capital Stock	17. Capital Stock Nonvoting Participating Preferred Stock . The Company’s preferred shares authorized, issued and outstanding consisted of the following: March 31, December 31, 2018 2017 Series A Shares authorized, $0.01 par value 20,000,000 20,000,000 Shares issued and outstanding — — Series B Shares authorized, $0.01 par value 150,000,000 150,000,000 Shares issued and outstanding (1) 823,188 823,188 Series C Shares authorized, $0.01 par value 6,000,000 6,000,000 Shares issued and outstanding (1) 143,458 246,522 Series D Shares authorized, $0.01 par value 20,000,000 20,000,000 Shares issued and outstanding — — (1) Shares held by PNC. Share Repurchases . The Company repurchased 0.6 million common shares in open market transactions under the share repurchase program for approximately $335 million during the three months ended March 31, 2018. At March 31, 2018, there were 5.8 million shares still authorized to be repurchased. PNC Capital Contribution . During the three months ended March 31, 2018, PNC surrendered to BlackRock 103,064 shares of BlackRock Series C Preferred to fund certain LTIP awards.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	18. Income Taxes On December 22, 2017, The Tax Cuts and Jobs Act (the “2017 Tax Act”) was enacted. The 2017 Tax Act significantly revises the U.S. tax code, including, but not limited to, (1) reducing the U.S. federal corporate tax rate from 35 percent to 21 percent, (2) requiring companies to pay a one-time tax on certain unrepatriated earnings of foreign subsidiaries, (3) generally eliminating U.S. federal income taxes on dividends from foreign subsidiaries, (4) creating new taxes on certain earnings of controlled foreign corporations, and (5) creating a new limitation on deductible net interest expense. BlackRock’s results in 2017 included a $1.2 billion net tax benefit related to the 2017 Tax Act. The Company has not made any additional measurement-period adjustments during the three months ended March 31, 2018. The Company may record adjustments to the provisional amounts during the measurement period as additional guidance from the U.S. Department of the Treasury is provided, as changes in the Company’s assumptions occur, and as further information and interpretations become available. For further information on the 2017 Tax Act, see Note 21, Income Taxes The first quarter 2018 income tax expense reflected a reduced tax rate associated with the 2017 Tax Act and included a $56 million discrete tax benefit related to stock-based compensation awards that vested in the first quarter of 2018. The first quarter 2017 income tax expense included an $81 million discrete tax benefit related to stock-based compensation awards that vested in the first quarter of 2017.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	19. Earnings Per Share Due to the similarities in terms between BlackRock nonvoting participating preferred stock and the Company’s common stock, the Company considers its participating preferred stock to be a common stock equivalent for purposes of earnings per share (“EPS”) calculations. As such, the Company has included the outstanding nonvoting participating preferred stock in the calculation of average basic and diluted shares outstanding. The following table sets forth the computation of basic and diluted EPS for the three months ended March 31, 2018 and 2017 under the treasury stock method: Three Months Ended March 31, (in millions, except shares and per share data) 2018 2017 Net income attributable to BlackRock $ 1,089 $ 859 Basic weighted-average shares outstanding 161,250,018 163,016,599 Dilutive effect of nonparticipating RSUs and stock options 1,668,943 1,839,584 Total diluted weighted-average shares outstanding 162,918,961 164,856,183 Basic earnings per share $ 6.75 $ 5.27 Diluted earnings per share $ 6.68 $ 5.21

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	20. Segment Information The Company’s management directs BlackRock’s operations as one business, the asset management business. The Company utilizes a consolidated approach to assess performance and allocate resources. As such, the Company operates in one business segment as defined in ASC 280-10. The following table illustrates total revenue for the three months ended March 31, 2018 and 2017 by geographic region. These amounts are aggregated on a legal entity basis and do not necessarily reflect where the customer resides or affiliated services are provided. Three Months Ended (in millions) March 31, Revenue 2018 2017 Americas $ 2,324 $ 2,043 Europe 1,093 906 Asia-Pacific 166 143 Total revenue $ 3,583 $ 3,092 The following table illustrates long-lived assets that consist of goodwill and property and equipment at March 31, 2018 and December 31, 2017 by geographic region. These amounts are aggregated on a legal entity basis and do not necessarily reflect where the asset is physically located. See Note 13, Revenue (in millions) March 31, December 31, Long-lived Assets 2018 2017 Americas $ 13,551 $ 13,560 Europe 172 168 Asia-Pacific 83 84 Total long-lived assets $ 13,806 $ 13,812 Americas primarily is comprised of the United States and Canada, while Europe primarily is comprised of the United Kingdom and Luxembourg. Asia-Pacific primarily is comprised of Hong Kong, Australia, Japan and Singapore.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	21. Subsequent Events In April 2018, the Company announced that it entered into an agreement to acquire Tennenbaum Capital Partners, LLC, a leading manager focused on middle market performing credit and special situation credit opportunities. The transaction is expected to be completed in the third quarter of 2018, subject to customary regulatory approvals and closing conditions. This transaction is not expected to be material to the Company’s condensed consolidated statements of financial condition or results of operations. In May 2018, the Company announced that it entered into an agreement to sell its minority interest in DSP BlackRock Investment Managers Pvt. Ltd. to The DSP Group. The Company currently has a 40% stake in the joint venture, which manages and markets a range of co-branded mutual funds in India. This transaction is expected to complete, subject to regulatory approval, once naming transfers and investment scheme unitholder communications are finalized. This transaction is not expected to be material to the Company’s condensed consolidated statements of financial condition or results of operations. The Company conducted a review for additional subsequent events and determined that no subsequent events had occurred that would require accrual or additional disclosures.

Significant Accounting Polici31

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation . These condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and include the accounts of the Company and its controlled subsidiaries. Noncontrolling interests on the condensed consolidated statements of financial condition represents the portion of consolidated sponsored investment funds in which the Company does not have direct equity ownership. Accounts and transactions between consolidated entities have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expense during the reporting periods. Actual results could differ from those estimates. Certain financial information that normally is included in annual financial statements, including certain financial statement footnotes, is not required for interim reporting purposes and has been condensed or omitted herein. These condensed consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements and notes related thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, which was filed with the Securities and Exchange Commission (“SEC”) on February 28, 2018 (“2017 Form 10-K”). The interim financial information at March 31, 2018 and for the three months ended March 31, 2018 and 2017 is unaudited. However, in the opinion of management, the interim information includes all normal recurring adjustments necessary for the fair presentation of the Company’s results for the periods presented. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year. Certain prior period presentations and disclosures, while not required to be recast, were reclassified to ensure comparability with current period classifications.
Accounting Pronouncements Adopted in the Three Months Ended March 31, 2018	Accounting Pronouncements Adopted in the Three Months Ended March 31, 2018. Revenue from Contracts with Customers. The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2 014-09, , and several amendments (collectively, “ASU 2014-09”). ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most previous revenue recognition guidance, including industry-specific guidance. The guidance also changes the accounting for certain contract costs and revises the criteria for determining if an entity is acting as a principal or agent in certain arrangements. The Company adopted ASU 2014-09 effective January 1, 2018 on a full retrospective basis, which required the Company to recast 2016 and 2017 previously reported amounts. The key impact of the standard relates to the Company’s presentation of certain revenue contracts and associated contract costs. The most significant of these changes relates to the presentation of certain distribution costs, which were previously presented net against revenue (contra-revenue) and are now presented as an expense on a gross basis. Revenue recognition related to investment advisory, administration fees and securities lending revenue as well as performance fees remained unchanged, which represents a substantial portion of the Company’s revenue. However, under ASU 2014-09, the Company may recognize certain performance fees, including carried interest, earlier than under the prior revenue recognition guidance. The impact to the condensed consolidated statement of financial condition upon adoption was related to a change in timing of recognition for certain technology and risk management revenue and related costs that resulted in an increase to other assets and other liabilities of $19 million and $25 million, respectively. The cumulative adjustment to retained earnings as of January 1, 2016 was a net decrease of $6 million. The following table presents the impact of the adoption to the condensed consolidated statement of income for the three months ended March 31, 2017. Three Months Ended March 31, 2017 (in millions, except shares and per share data) Previously Reported Adoption of the New Revenue Standard Adjustment Recast Total revenue $ 2,824 $ 268 $ 3,092 Total expense 1,677 272 1,949 Operating income $ 1,147 $ (4 ) $ 1,143 Income tax expense $ 269 $ (1 ) $ 268 Net income $ 871 $ (3 ) $ 868 Net income attributable to BlackRock, Inc. $ 862 $ (3 ) $ 859 Earnings per share attributable to BlackRock, Inc. common stockholders: Basic $ 5.29 $ (0.02 ) $ 5.27 Diluted $ 5.23 $ (0.02 ) $ 5.21 Recognition and Measurement of Financial Instruments . In January 2016, the FASB issued ASU 2016-01, (“ASU 2016-01”). ASU 2016-01 amends guidance on the classification and measurement of financial instruments, including requiring an entity to measure substantially all equity securities (other than those accounted for under the equity method of accounting) at fair value through earnings. ASU 2016-01 also amends certain disclosure requirements associated with the fair value of financial instruments. The Company adopted ASU 2016-01 using a modified retrospective approach on January 1, 2018. The reclassification of unrealized gains (losses) on equity securities within accumulated other comprehensive income to retained earnings was not material upon adoption. Cash Flow Classification. In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), which amends and clarifies the current guidance to reduce diversity in practice of the classification of certain cash receipts and payments in the consolidated statement of cash flows. The Company adopted ASU 2016-15 on January 1, 2018 retrospectively to all periods presented . The adoption of ASU 2016-15 did not have a material impact on the condensed consolidated statement of cash flows. Restricted Cash. In November 2016, the FASB issued 2016-18, , which clarifies the classification and presentation of restricted cash in the statement of cash flows (“ASU 2016-18”). The Company adopted ASU 2016-18 on January 1, 2018 retrospectively to all periods presented. The adoption of ASU 2016-18 did not have a material impact on the condensed consolidated statement of cash flows. See Note 3, , for additional disclosure requirements related to restricted cash. Reclassifications from Accumulated Other Comprehensive Income. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (“ASU 2018-02”). ASU 2018-02 allows reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. The Company adopted ASU 2018-02 prospectively on January 1, 2018. The adoption of ASU 2018-02 did not have a material impact on the condensed consolidated statement of financial condition.
Revenue Recognition	Revenue Recognition. Revenue is recognized upon transfer of control of promised services to customers in an amount that reflects consideration to which the Company expects to be entitled in exchange for those services (the “transaction price”). The Company enters into contracts that can include multiple services, which are accounted for separately if they are determined to be distinct. Consideration for the Company’s services is generally in the form of variable consideration because the amount of fees is subject to market conditions that are outside of the Company’s influence. The Company includes variable consideration as part of its transaction price when it is no longer probable of significant reversal, i.e. when the associated uncertainty is resolved. For some contracts with customers, the Company has discretion to involve a third party in providing services to the customer. Generally, the Company is deemed to be the principal in these arrangements because the Company controls the promised services before they are transferred to customers, and accordingly presents the revenue gross of related costs. Investment Advisory, Administration Fees and Securities Lending Revenue. Investment advisory and administration fees are recognized as the services are performed over time. Such fees are primarily based on agreed-upon percentages of net asset value, assets under management (“AUM”) or committed capital. These fees are affected by changes in AUM, including market appreciation or depreciation, foreign exchange translation and net inflows or outflows. Investment advisory and administration fees for investment funds are shown net of fees waived pursuant to contractual expense limitations of the funds or voluntary waivers. In addition, the Company may contract with third parties to provide sub-advisory services on its behalf. The Company presents the investment advisory fees and associated costs to such advisors on a gross basis in the condensed consolidated statements of income where it is deemed to be the principal. The Company earns revenue by lending securities on behalf of clients, primarily to highly rated banks and broker-dealers. Revenue is recognized over time as services are performed. Generally, the securities lending fees are shared between the Company and the funds or other third-party accounts managed by the Company from which the securities are borrowed. Investment Advisory Performance Fees / Carried Interest. The Company receives investment advisory performance fees, including incentive allocations (carried interest) from certain actively managed investment funds and certain separately managed accounts. These performance fees are dependent upon exceeding specified relative or absolute investment return thresholds, which may vary by product or account, and include monthly, quarterly, annually or longer measurement periods. A portion of the fees the Company recognizes may be partially related to the services performed in prior periods that meet the recognition criteria in the current period. The Company is allocated carried interest from certain alternative investment products upon exceeding performance thresholds. BlackRock may be required to reverse/return all, or part, of such carried interest allocations depending upon future performance of these funds. Therefore, carried interest subject to such clawback provisions is recorded in investments/investments of consolidated VIEs or cash/cash of consolidated VIEs to the extent that it is distributed, on its condensed consolidated statements of financial condition. Performance fees, including carried interest, are recognized when it is determined that they are no longer probable of significant reversal (such as upon the sale of a fund’s investment or when the amount of AUM becomes known as of the end of a specified measurement period). Significant judgement is involved in making such determination. At each reporting date, the Company considers various factors in estimating performance fees to be recognized, including carried interest. These factors include but are not limited to whether: (1) the fees are dependent on the market and thus are highly susceptible to factors outside the Company’s influence; (2) the fees have a large number and a broad range of possible amounts; and (3) the funds or separately managed accounts have the ability to invest or reinvest its sales proceeds. The Company records a contract liability for deferred carried interest to the extent it receives cash or capital allocations related to carried interest prior to meeting the revenue recognition criteria. At March 31, 2018 and December 31, 2017, the Company had $224 million and $219 million, respectively, of deferred carried interest recorded in other liabilities/other liabilities of consolidated VIEs on the condensed consolidated statements of financial condition. A portion of the deferred carried interest may also be paid to certain employees. The ultimate timing of the recognition of performance fee revenue and related compensation expense, if any, for these products is unknown. Technology and risk management revenue. BlackRock offers investment management technology systems, risk management services, wealth management and digital distribution tools on a fee basis. Clients include banks, insurance companies, official institutions, pension funds, asset managers, retail distributors and other investors. Fees earned for technology and risk management revenue are recorded as services are performed and are generally determined using the value of positions on the Aladdin platform or on a fixed-rate basis. Distribution Fees. The Company accounts for fund distribution services and shareholder servicing as distinct services, separate from fund management services, because customers can benefit from each of the services on their own and because the services are separately identifiable (that is, the nature of the promised services is to transfer each service individually). The Company records upfront and ongoing sales commissions as distribution fee revenue for serving as the principal underwriter and/or distributor for certain mutual funds that it manages. The Company recognizes the upfront fees for front-end load funds on a trade date basis when the services are performed and the amount the Company is entitled to is known. The on-going distribution fees are generally based on net asset values and are recognized when the amount is known. Distribution services are satisfied at a point in time. Consequently, a portion of the on-going distribution fees the Company recognized may be related to the services performed in prior periods that met the recognition criteria in the current period. The Company recognizes ongoing shareholder servicing fee revenue when and as shareholder services are performed over time. The Company contracts with third parties for various fund distribution services and shareholder servicing of certain funds to be performed on its behalf. These arrangements are generally priced as a portion of the fee paid to the Company by the fund or as an agreed-upon percentage of net asset value. The Company presents its distribution fees and distribution and servicing costs incurred on a gross basis in the condensed consolidated statements of income as it is deemed to be the principal in such transactions. Advisory and other revenue. Advisory and other revenue primarily includes fees earned for advisory services, fees earned for transition management services primarily comprised of commissions recognized in connection with buying and selling securities on behalf of customers, and equity method investment earnings related to certain strategic investments. Advisory services fees are determined using fixed-rate fees and are recognized over time as the related services are performed. Commissions related to transition management services are recorded on a trade-date basis as securities transactions occur.
Investments	Investments. Investments in Debt Securities. BlackRock classifies debt investments as available-for-sale, held-to-maturity or trading based on the Company’s intent to sell the security or, its intent and ability to hold the debt security to maturity. Available-for-sale debt securities are those securities that are not classified as trading or held-to-maturity. Available-for-sale debt securities include certain investments in collateralized loan obligations (“CLOs”) and are carried at fair value on the condensed consolidated statements of financial condition with changes in fair value recorded in the accumulated other comprehensive income (loss) component of stockholders’ equity in the period of the change. Upon the disposition of an available-for-sale security, the Company reclassifies the gain or loss on the security from accumulated other comprehensive income (loss) to nonoperating income (expense) on the condensed consolidated statements of income. Held-to-maturity debt securities are purchased with the positive intent and ability to be held to maturity and are recorded at amortized cost on the condensed consolidated statements of financial condition. Trading securities are those investments that are purchased principally for the purpose of selling them in the near term. Trading securities are carried at fair value on the condensed consolidated statements of financial condition with changes in fair value recorded in nonoperating income (expense) on the condensed consolidated statements of income in the period of the change. Trading securities include certain investments in CLOs for which the fair value option is elected in order to reduce operational complexity of bifurcating embedded derivatives. Investments in Equity Securities. Equity securities are generally carried at fair value on the condensed consolidated statements of financial condition with changes in the fair value recorded through net income (“FVTNI”) within nonoperating income (expense) in the period of change. For nonmarketable equity securities, the Company generally elected to apply the practicality exception to apply fair value measurement, under which such securities will be measured at cost, less impairment, plus or minus observable price changes for identical or similar securities of the same issuer with such changes recorded in the condensed consolidated statements of income in the period of the change. Dividends received from the investment are recorded as dividend income within nonoperating income (expense). Equity Method. For equity investments where BlackRock does not control the investee, and where it is not the primary beneficiary (“PB”) of a VIE, but can exert significant influence over the financial and operating policies of the investee, the Company follows the equity method of accounting. BlackRock’s share of the investee’s underlying net income or loss is recorded as net gain (loss) on investments within nonoperating income (expense) and as other revenue for certain strategic investments since such companies are considered to be an extension of BlackRock’s core business. BlackRock’s share of net income of the investee is recorded based upon the most current information available at the time, which may precede the date of the condensed consolidated statement of financial condition. Distributions received from the investment reduce the Company’s carrying value of the investee and the cost basis if deemed to be a return of capital. Impairments of Investments. Management periodically assesses equity method, available-for-sale and held-to-maturity investments for other-than-temporary impairment (“OTTI”). If an OTTI exists, an impairment charge would be recorded in the condensed consolidated statements of income. For equity method investments and held-to-maturity investments, if circumstances indicate that an OTTI may exist, the investments are evaluated using market values, where available, or the expected future cash flows of the investment. If the Company determines an OTTI exists, an impairment charge is recognized for the excess of the carrying amount of the investment over its estimated fair value. For the Company’s investments in CLOs, the Company reviews cash flow estimates over the life of each CLO investment. On a quarterly basis, if the present value of the estimated future cash flows is lower than the carrying value of the investment and there is an adverse change in estimated cash flows, an impairment is considered to be other-than-temporary. An impairment charge is recognized for the excess of the carrying amount of the investment over its estimated fair value. In addition, for nonmarketable equity securities that are accounted for under the measurement alternative to fair value, the Company applies the simplified impairment model that does not require the Company to consider whether the impairment is other than temporary.
Fair Value Measurements	Fair Value Measurements. Hierarchy of Fair Value Inputs . The Company uses a fair value hierarchy that prioritizes inputs to valuation approaches used to measure fair value. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. Assets and liabilities measured and reported at fair value are classified and disclosed in one of the following categories: Level 1 Inputs: Quoted prices (unadjusted) in active markets for identical assets or liabilities at the reporting date. • Level 1 assets may include listed mutual funds, ETFs, listed equities and certain exchange-traded derivatives. Level 2 Inputs: Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities that are not active; quotes from pricing services or brokers for which the Company can determine that orderly transactions took place at the quoted price or that the inputs used to arrive at the price are observable; and inputs other than quoted prices that are observable, such as models or other valuation methodologies. • Level 2 assets may include debt securities, investments in CLOs, short-term floating-rate notes, asset-backed securities, securities held within consolidated hedge funds, restricted public securities valued at a discount, as well as over-the-counter derivatives, including interest and inflation rate swaps and foreign currency exchange contracts that have inputs to the valuations that generally can be corroborated by observable market data. Level 3 Inputs: Unobservable inputs for the valuation of the asset or liability, which may include nonbinding broker quotes. Level 3 assets include investments for which there is little, if any, market activity. These inputs require significant management judgment or estimation. • Level 3 assets may include direct private equity investments held within consolidated funds and investments in CLOs. • Level 3 liabilities include contingent liabilities related to acquisitions valued based upon discounted cash flow analyses using unobservable market data. Significance of Inputs. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the financial instrument. Valuation Approaches. The fair values of certain Level 3 assets and liabilities were determined using various valuation approaches as appropriate, including third-party pricing vendors, broker quotes and market and income approaches. Such quotes and modeled prices are evaluated for reasonableness through various procedures, including due diligence reviews of third-party pricing vendors, variance analyses, consideration of the current market environment and other analytical procedures. A significant number of inputs used to value equity, debt securities and investments in CLOs is sourced from third-party pricing vendors. Generally, prices obtained from pricing vendors are categorized as Level 1 inputs for identical securities traded in active markets and as Level 2 for other similar securities if the vendor uses observable inputs in determining the price. Annually, BlackRock’s internal valuation committee or other designated groups review both the valuation approaches, including the general assumptions and methods used to value various asset classes, and operational processes with these vendors. On a quarterly basis, meetings are held with key vendors to identify any significant changes to the vendors’ processes. In addition, quotes obtained from brokers generally are nonbinding and categorized as Level 3 inputs. However, if the Company is able to determine that market participants have transacted for the asset in an orderly manner near the quoted price or if the Company can determine that the inputs used by the broker are observable, the quote is classified as a Level 2 input. Investments Measured at Net Asset Values. As a practical expedient, the Company uses net asset value (“NAV”) as the fair value for certain investments. The inputs to value these investments may include BlackRock capital accounts for its partnership interests in various alternative investments, including hedge funds, real assets and private equity funds, which may be adjusted by using the returns of certain market indices. The various partnerships generally are investment companies, which record their underlying investments at fair value based on fair value policies established by management of the underlying fund. Fair value policies at the underlying fund generally require the fund to utilize pricing/valuation information from third-party sources, including independent appraisals. However, in some instances, current valuation information for illiquid securities or securities in markets that are not active may not be available from any third-party source or fund management may conclude that the valuations that are available from third-party sources are not reliable. In these instances, fund management may perform model-based analytical valuations that could be used as an input to value these investments.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities . The Company does not use derivative financial instruments for trading or speculative purposes. The Company uses derivative financial instruments primarily for purposes of hedging exposures to fluctuations in foreign currency exchange rates of certain assets and liabilities, and market exposures for certain seed investments. However, certain consolidated sponsored investment funds may also utilize derivatives as a part of their investment strategy. Changes in the fair value of the Company’s derivative financial instruments are recognized in earnings and, where applicable, are offset by the corresponding gain or loss on the related foreign-denominated assets or liabilities or hedged investments, on the condensed consolidated statements of income. The Company may also use financial instruments designated as net investment hedges for accounting purposes to hedge net investments in international subsidiaries whose functional currency is not U.S. dollars. The gain or loss from revaluing accounting hedges of net investments in foreign operations at the spot rate is deferred and reported within accumulated other comprehensive income on the condensed consolidated statements of financial condition. The Company reassesses the effectiveness of its net investment hedge on a quarterly basis.
Money Market Fee Waivers	Money Market Fee Waivers . The Company may voluntarily waive a portion of its management fees on certain money market funds to ensure that they maintain a targeted level of daily net investment income (the “Yield Support waivers”). During the three months ended March 31, 2018 and 2017, waivers that resulted in a reduction of management fees were immaterial. BlackRock may increase or decrease the level of Yield Support waivers in future periods.
Separate Account Assets and Liabilities	Separate Account Assets and Liabilities . Separate account assets are maintained by BlackRock Life Limited, a wholly owned subsidiary of the Company, which is a registered life insurance company in the United Kingdom, and represent segregated assets held for purposes of funding individual and group pension contracts. The life insurance company does not underwrite any insurance contracts that involve any insurance risk transfer from the insured to the life insurance company. The separate account assets primarily include equity securities, debt securities, money market funds and derivatives. The separate account assets are not subject to general claims of the creditors of BlackRock. These separate account assets and the related equal and offsetting liabilities are recorded as separate account assets and separate account liabilities on the condensed consolidated statements of financial condition. The net investment income attributable to separate account assets supporting individual and group pension contracts accrues directly to the contract owner and is not reported on the condensed consolidated statements of income. While BlackRock has no economic interest in these separate account assets and liabilities, BlackRock earns policy administration and management fees associated with these products, which are included in investment advisory, administration fees and securities lending revenue on the condensed consolidated statements of income.
Separate Account Collateral Assets Held and Liabilities Under Securities Lending Agreements	Separate Account Collateral Assets Held and Liabilities Under Securities Lending Agreements. The Company facilitates securities lending arrangements whereby securities held by separate accounts maintained by BlackRock Life Limited are lent to third parties under global master securities lending agreements. In exchange, the Company receives legal title to the collateral with minimum values generally ranging from approximately 102% to 112% of the value of the securities lent in order to reduce counterparty risk. The required collateral value is calculated on a daily basis. The global master securities lending agreements provide the Company the right to request additional collateral or, in the event of borrower default, the right to liquidate collateral. The securities lending transactions entered into by the Company are accompanied by an agreement that entitles the Company to request the borrower to return the securities at any time; therefore, these transactions are not reported as sales. The Company records on the condensed consolidated statements of financial condition the cash and noncash collateral received under these BlackRock Life Limited securities lending arrangements as its own asset in addition to an equal and offsetting collateral liability for the obligation to return the collateral. The securities lending revenue earned from lending securities held by the separate accounts is included in investment advisory, administration fees and securities lending revenue on the condensed consolidated statements of income. During the three months ended March 31, 2018 and 2017, the Company had not resold or repledged any of the collateral received under these arrangements. At March 31, 2018 and December 31, 2017, the fair value of loaned securities held by separate accounts was approximately $24.8 billion and $22.3 billion, respectively, and the fair value of the collateral held under these securities lending agreements was approximately $27.2 billion and $24.2 billion, respectively.
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted. Leases. In February 2016, the FASB issued ASU 2016-02, (“ASU 2016-02”), which requires lessees to recognize assets and liabilities arising from most operating leases on the condensed consolidated statements of financial condition. The Company expects to record assets and liabilities for its current operating leases upon adoption of ASU 2016-02 and does not expect the adoption to have a material impact on its results of operations or cash flows. ASU 2016-02 is effective for the Company on January 1, 2019, and the Company intends to apply the practical expedients allowed by the standard upon transition. See Note 13 of the 2017 Form 10-K for information on the Company’s operating lease commitments.

Significant Accounting Polici32

Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Standards Update 2014-09 [Member]
Impact of ASU 2014-09 Adoption to Condensed Consolidated Statement of Income	The following table presents the impact of the adoption to the condensed consolidated statement of income for the three months ended March 31, 2017. Three Months Ended March 31, 2017 (in millions, except shares and per share data) Previously Reported Adoption of the New Revenue Standard Adjustment Recast Total revenue $ 2,824 $ 268 $ 3,092 Total expense 1,677 272 1,949 Operating income $ 1,147 $ (4 ) $ 1,143 Income tax expense $ 269 $ (1 ) $ 268 Net income $ 871 $ (3 ) $ 868 Net income attributable to BlackRock, Inc. $ 862 $ (3 ) $ 859 Earnings per share attributable to BlackRock, Inc. common stockholders: Basic $ 5.29 $ (0.02 ) $ 5.27 Diluted $ 5.23 $ (0.02 ) $ 5.21

Cash, Cash Equivalents and Re33

Cash, Cash Equivalents and Restricted Cash (Tables)	3 Months Ended
	Mar. 31, 2018
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash and cash equivalents reported within the condensed consolidated statements of financial condition to the cash, cash equivalents, and restricted cash reported within the condensed consolidated statements of cash flows. March 31, December 31, (in millions) 2018 2017 Cash and cash equivalents $ 5,978 $ 6,894 Cash and cash equivalents of consolidated VIEs 103 144 Restricted cash included in Other assets 62 58 Total cash, cash equivalents and restricted cash $ 6,143 $ 7,096

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Investments Debt And Equity Securities [Abstract]
Summary of Carrying Value of Total Investments	A summary of the carrying value of total investments is as follows: March 31, (in millions) 2018 (1) Debt securities: Available-for-sale investments $ 151 Held-to-maturity investments 132 Trading securities ($266 debt securities of consolidated sponsored investment funds) 293 Total debt securities 576 Equity securities at FVTNI ($284 equity securities of consolidated sponsored investment funds) 648 Equity method investments (2) 703 Federal Reserve Bank stock (3) 91 Carried interest (4) 32 Total investments $ 2,050 (in millions) December 31, 2017 (1) Available-for-sale investments $ 103 Held-to-maturity investments 102 Trading investments: Consolidated sponsored investment funds: Debt securities 267 Equity securities 245 Other equity and debt securities 267 Deferred compensation plan mutual funds 56 Total trading investments 835 Equity method investments (2) 816 Cost method investments (3) 93 Carried interest (4) 32 Total investments $ 1,981 (1) Amounts at March 31, 2018 reflect the adoption of ASU 2016-01. See Note 2, Significant Accounting Policies (2) Equity method investments primarily include BlackRock’s direct investments in certain BlackRock sponsored investment funds. (3) Amounts include Federal Reserve Bank stock, which is held for regulatory purposes and is restricted from sale. At December 31, 2017, amount also includes other nonmarketable securities, which were immaterial. At March 31, 2018 and December 31, 2017, there were no indicators of impairment on these investments. (4) Carried interest of consolidated sponsor investment funds accounted for as voting rights entities (“VREs”) represents allocations to BlackRock’s general partner capital accounts from certain funds. These balances are subject to change upon cash distributions, additional allocations or reallocations back to limited partners within the respective funds.
Summary of Cost and Carrying Value of Equity and Trading Debt Securities	A summary of the cost and carrying value of equity and trading debt securities is as follows: March 31, 2018 (1) (in millions) Cost Carrying Value Trading debt securities: Corporate debt $ 166 $ 169 Government debt 62 62 Asset/mortgage-backed debt 62 62 Equity securities at FVTNI: Equity securities/multi-asset mutual funds 577 614 Deferred compensation plan mutual funds 21 34 Total equity and trading debt securities $ 888 $ 941 December 31, 2017 (1) (in millions) Cost Carrying Value Trading investments: Deferred compensation plan mutual funds $ 34 $ 56 Equity securities/multi-asset mutual funds 446 493 Debt securities Corporate debt 152 157 Government debt 72 73 Asset/mortgage backed debt 56 56 Total trading investments $ 760 $ 835 (1) Amounts at March 31, 2018 reflect the adoption of ASU 2016-01. See Note 2, Significant Accounting Policies

Consolidated Voting Rights En35

Consolidated Voting Rights Entities (Tables)	3 Months Ended
	Mar. 31, 2018
Text Block [Abstract]
Consolidated VREs Included in Condensed Consolidated Statements of Financial Condition	The following table presents the balances related to these consolidated VREs that were recorded on the condensed consolidated statements of financial condition, including BlackRock’s net interest in these funds: March 31, December 31, (in millions) 2018 2017 Cash and cash equivalents $ 44 $ 63 Investments: Trading debt securities 266 267 Equity securities at FVTNI 284 245 Total investments 550 512 Other assets 15 13 Other liabilities (42 ) (37 ) Noncontrolling interests ("NCI") (87 ) (91 ) BlackRock’s net interests in consolidated VREs $ 480 $ 460

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2018
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Schedule of VIE Assets and Liabilities	Consolidated VIE assets and liabilities are presented after intercompany eliminations in the following table: March 31, December 31, (in millions) 2018 2017 Assets of consolidated VIEs: Cash and cash equivalents $ 103 $ 144 Investments: Trading debt securities 769 475 Equity securities at FVTNI 295 440 Other investments 300 312 Carried interest 273 266 Other assets 113 66 Total investments and other assets 1,750 1,559 Liabilities of consolidated VIEs (425 ) (369 ) Noncontrolling interests (518 ) (375 ) BlackRock's net interests in consolidated VIEs $ 910 $ 959
Schedule of Net Gain (Loss) Related to Consolidated VIEs	Net gain (loss) related to consolidated VIEs is presented in the following table: Three Months Ended March 31, (in millions) 2018 2017 Nonoperating net gain (loss) on consolidated VIEs $ 2 $ 33 Net income (loss) attributable to NCI on consolidated VIEs $ 5 $ 8
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Schedule of VIE Assets and Liabilities	At March 31, 2018 and December 31, 2017, the Company’s carrying value of assets and liabilities included on the condensed consolidated statements of financial condition pertaining to nonconsolidated VIEs and its maximum risk of loss related to VIEs for which it held a variable interest, but for which it was not the PB, was as follows: (in millions) At March 31, 2018 Investments Advisory Fee Receivables Other Net Assets (Liabilities) Maximum Risk of Loss (1) Sponsored investment products $ 342 $ 30 $ (7 ) $ 389 At December 31, 2017 Sponsored investment products $ 263 $ 15 $ (7 ) $ 295 (1) At both March 31, 2018 and December 31, 2017, BlackRock’s maximum risk of loss associated with these VIEs primarily related to BlackRock’s investments and the collection of advisory fee receivables.

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis and other assets not held at fair value March 31, 2018 (1) (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV (2) Other Assets Not Held at Fair Value (3) March 31, 2018 Assets: Investments: Equity securities at FVTNI: Deferred compensation plan mutual funds $ 34 $ — $ — $ — $ — $ 34 Equity securities/Multi-asset mutual funds 614 — — — — 614 Total equity securities 648 — — — — 648 Debt securities: Available-for-sale — 125 26 — — 151 Trading securities — 288 5 — — 293 Held-to-maturity securities — — — — 132 132 Total debt securities — 413 31 — 132 576 Equity method: Equity and fixed income mutual funds 116 — — 15 — 131 Other — — — 569 3 572 Total equity method 116 — — 584 3 703 Federal Reserve Bank Stock — — — — 91 91 Carried interest — — — — 32 32 Total investments 764 413 31 584 258 2,050 Investments of consolidated VIEs: Equity securities 295 — — — — 295 Trading debt securities — 769 — — — 769 Private / public equity (4) 3 3 116 56 72 250 Other — — — 50 — 50 Carried interest — — — — 273 273 Total investments of consolidated VIEs 298 772 116 106 345 1,637 Other assets (5) — 35 — — — 35 Separate account assets 107,095 35,063 — — 712 142,871 Separate account collateral held under securities lending agreements: Equity securities 18,543 — — — — 18,543 Debt securities — 8,704 — — — 8,704 Total separate account collateral held under securities lending agreements 18,543 8,704 — — — 27,247 Total $ 126,700 $ 44,987 $ 147 $ 690 $ 1,315 $ 173,840 Liabilities: Separate account collateral liabilities under securities lending agreements $ 18,543 $ 8,704 $ — $ — $ — $ 27,247 Other liabilities (6) — 7 242 — — 249 Total $ 18,543 $ 8,711 $ 242 $ — $ — $ 27,496 (1) Significant Accounting Policies (2) Amounts are comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. (3) Amounts are comprised of investments held at cost or amortized cost, carried interest and certain equity method investments, which include sponsored investment funds and other assets, which are not accounted for under a fair value measure. In accordance with GAAP, certain equity method investees do not account for both their financial assets and liabilities under fair value measures; therefore, the Company’s investment in such equity method investees may not represent fair value. (4) Level 3 amounts primarily include direct investments in private equity companies held by private equity funds. (5) Amounts include fair value of forward foreign currency exchange contracts (see Note 8, Derivatives and Hedging (6) Amounts primarily include contingent liabilities related to certain acquisitions (see Note 12, Commitments and Contingencies Assets and liabilities measured at fair value on a recurring basis and other assets not held at fair value December 31, 2017 (1) (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investments Measured at NAV (2) Other Assets Not Held at Fair Value (3) December 31, 2017 Assets: Investments Available-for-sale $ 7 $ 96 $ — $ — $ — $ 103 Held-to-maturity debt securities — — — — 102 102 Trading: Deferred compensation plan mutual funds 56 — — — — 56 Equity/Multi-asset mutual funds 493 — — — — 493 Debt securities / fixed income mutual funds 2 284 — — — 286 Total trading 551 284 — — — 835 Equity method: Equity and fixed income mutual funds 183 — — 12 — 195 Other — — — 609 12 621 Total equity method 183 — — 621 12 816 Cost method investments — — — — 93 93 Carried interest — — — — 32 32 Total investments 741 380 — 621 239 1,981 Separate account assets 114,422 34,582 — — 933 149,937 Separate account collateral held under securities lending agreements: Equity securities 18,778 — — — — 18,778 Debt securities — 5,412 — — — 5,412 Total separate account collateral held under securities lending agreements 18,778 5,412 — — — 24,190 Investments of consolidated VIEs: Trading: Equity securities 440 — — — — 440 Debt securities — 475 — — — 475 Private / public equity (4) 6 2 116 59 76 259 Other — — — 53 — 53 Carried interest — — — — 266 266 Total investments of consolidated VIEs 446 477 116 112 342 1,493 Total $ 134,387 $ 40,851 $ 116 $ 733 $ 1,514 $ 177,601 Liabilities: Separate account collateral liabilities under securities lending agreements $ 18,778 $ 5,412 $ — $ — $ — $ 24,190 Other liabilities (5) — 7 236 — — 243 Total $ 18,778 $ 5,419 $ 236 $ — $ — $ 24,433 (1) Amounts at December 31, 2017 reflect accounting guidance prior to ASU 2016-01. (2) Amounts are comprised of certain investments measured at fair value using NAV (or its equivalent) as a practical expedient. (3) Amounts are comprised of investments held at cost or amortized cost, carried interest and certain equity method investments, which include sponsored investment funds and other assets, which are not accounted for under a fair value measure. In accordance with GAAP, certain equity method investees do not account for both their financial assets and liabilities under fair value measures; therefore, the Company’s investment in such equity method investees may not represent fair value. (4) Level 3 amounts include direct investments in private equity companies held by private equity funds. (5) Amounts primarily include contingent liabilities related to certain acquisitions (see Note 12, Commitments and Contingencies
Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis	Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis for the Three Months Ended March 31, 2018 (in millions) December 31, 2017 Realized and Unrealized Gains (Losses) in Earnings and OCI Purchases Sales and Maturities Issuances and other Settlements Transfers into Level 3 Transfers out of Level 3 March 31, 2018 (1) Total Net Unrealized Gains (Losses) Included in Earnings (2) Assets: Investments: Debt securities: Available-for-sale securities (3) $ — $ — $ 26 $ — $ — $ — $ — $ 26 Trading securities — — 5 — — — — 5 Total investments — — 31 — — — — 31 Assets of consolidated VIEs - Private equity 116 — — — — — — 116 Total Level 3 assets $ 116 $ — $ 31 $ — $ — $ — $ — $ 147 Liabilities: Other liabilities (4) $ 236 (6 ) $ — $ — $ — $ — $ — $ 242 $ (6 ) (1) Amounts at March 31, 2018 reflect the adoption of ASU 2016-01. See Note 2, Significant Accounting Policies (2) Earnings attributable to the change in unrealized gains (losses) relating to assets and liabilities still held at the reporting date. (3) Amounts include investments in CLOs. (4) Other liabilities amount includes contingent liabilities in connection with certain acquisitions. Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis for the Three Months Ended March 31, 2017 (1) (in millions) December 31, 2016 Realized and Unrealized Gains (Losses) in Earnings and OCI Purchases Sales and Maturities Issuances and other Settlements Transfers into Level 3 Transfers out of Level 3 (2) March 31, 2017 Total Net Unrealized Gains (Losses) Included in Earnings (3) Assets: Investments: Available-for-sale securities (4) $ 24 $ — $ — $ — $ — $ — $ (24 ) $ — Trading 7 — — — — — (7 ) — Total investments 31 — — — — — (31 ) — Assets of consolidated VIEs - Private equity 112 1 — — — — — 113 $ 1 Total Level 3 assets $ 143 $ 1 $ — $ — $ — $ — $ (31 ) $ 113 Liabilities: Other liabilities (5) $ 115 $ 2 $ — $ — $ — $ — $ — $ 113 $ 2 (1) Amounts at March 31, 2017 reflect accounting guidance prior to ASU 2016-01. (2) Amounts include transfers out of Level 3 due to availability of observable market inputs from pricing vendors. (3) Earnings attributable to the change in unrealized gains (losses) relating to assets and liabilities still held at the reporting date. (4) Amounts include investments in CLOs. (5) Other liabilities amount includes contingent liabilities in connection with certain acquisitions.
Fair Value of Financial Assets and Financial Liabilities	Disclosures of Fair Value for Financial Instruments Not Held at Fair Value . At March 31, 2018 and December 31, 2017, the fair value of the Company’s financial instruments not held at fair value are categorized in the table below: March 31, 2018 December 31, 2017 (in millions) Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Fair Value Hierarchy Financial Assets: Cash and cash equivalents $ 5,978 $ 5,978 $ 6,894 $ 6,894 Level 1 (1) (2) Cash and cash equivalents of consolidated VIEs 103 103 144 144 Level 1 (1) (2) Other assets 62 62 70 70 Level 1 (1) (3) Financial Liability: Long-term borrowings 5,036 5,134 5,014 5,225 Level 2 (4) (1) Cash and cash equivalents are carried at either cost or amortized cost, which approximates fair value due to their short-term maturities. (2) At March 31, 2018 and December 31, 2017, approximately $204 million and $163 million, respectively, of money market funds were recorded within cash and cash equivalents on the condensed consolidated statements of financial condition. In addition, at March 31, 2018 and December 31, 2017, approximately $13 million and $14 million, respectively, of money market funds were recorded within cash and cash equivalents of consolidated VIEs. Money market funds are valued based on quoted market prices, or $1.00 per share, which generally is the NAV of the fund. (3) Other assets primarily include restricted cash. (4) Long-term borrowings are recorded at amortized cost net of debt issuance costs. The fair value of the long-term borrowings, including the current portion of long-term borrowings, is estimated using market prices at the end of March 2018 and December 2017, respectively. See Note 11, Borrowings
Investments in Certain Entities that Calculate Net Asset Value per Share	The following tables list information regarding all investments that use a fair value measurement to account for both their financial assets and financial liabilities in their calculation of a NAV per share (or equivalent). March 31, 2018 (in millions) Ref Fair Value Total Unfunded Commitments Redemption Frequency Redemption Notice Period Equity method: (1) Hedge funds/funds of hedge funds (a) $ 168 $ 64 Daily/Monthly (30%) Quarterly (29%) N/R (41%) 1 – 90 days Private equity funds (b) 99 85 N/R N/R Real assets funds (c) 302 79 Quarterly (78%) N/R (22%) 60 days Other 15 15 Daily/Monthly (79%) N/R (21%) 3 – 5 days Consolidated VIEs: Private equity funds of funds (d) 56 18 N/R N/R Hedge fund (a) 14 — Quarterly 90 days Real assets funds (c) 36 48 N/R N/R Total $ 690 $ 309 December 31, 2017 (in millions) Ref Fair Value Total Unfunded Commitments Redemption Frequency Redemption Notice Period Equity method: (1) Hedge funds/funds of hedge funds (a) $ 230 $ 48 Daily/Monthly (21%) Quarterly (49%) N/R (30%) 1 – 90 days Private equity funds (b) 94 86 N/R N/R Real assets funds (c) 282 69 Quarterly (83%) N/R (17%) 60 days Other 15 14 Daily (80%) N/R (20%) 5 days Consolidated VIEs: Private equity funds of funds (d) 59 20 N/R N/R Hedge fund (a) 19 — Quarterly 90 days Real assets funds (c) 34 49 N/R N/R Total $ 733 $ 286 N/R – not redeemable (1) Comprised of equity method investments, which include investment companies, which account for their financial assets and most financial liabilities under fair value measures; therefore, the Company’s investment in such equity method investees approximates fair value. (a) This category includes hedge funds and funds of hedge funds that invest primarily in equities, fixed income securities, distressed credit, opportunistic and mortgage instruments and other third-party hedge funds. The fair values of the investments have been estimated using the NAV of the Company’s ownership interest in partners’ capital. It was estimated that the investments in the funds that are not subject to redemption will be liquidated over a weighted-average period of seven years at both March 31, 2018 and December 31, 2017. (b) This category includes several private equity funds that initially invest in nonmarketable securities of private companies, which ultimately may become public in the future. The fair values of these investments have been estimated using capital accounts representing the Company’s ownership interest in the funds as well as other performance inputs. The Company’s investment in each fund is not subject to redemption and is normally returned through distributions as a result of the liquidation of the underlying assets of the private equity funds. It was estimated that the investments in these funds will be liquidated over a weighted-average period of approximately six years at both March 31, 2018 and December 31, 2017. (c) This category includes several real assets funds that invest directly and indirectly in real estate and infrastructure. The fair values of the investments have been estimated using capital accounts representing the Company’s ownership interest in the funds. The Company’s investments that are not subject to redemption or are not currently redeemable are normally returned through distributions and realizations of the underlying assets of the funds. It is estimated that the investments in these funds not subject to redemptions will be liquidated over a weighted-average period of approximately eight years at both March 31, 2018 and December 31, 2017. The total remaining unfunded commitments to real assets funds were $128 million and $117 million at March 31, 2018 and December 31, 2017, respectively. The Company had contractual obligations to the real assets funds of $108 million at March 31, 2018 and $98 million at December 31, 2017. (d)

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill Activity	Goodwill activity during the three months ended March 31, 2018 was as follows: (in millions) December 31, 2017 $ 13,220 Goodwill adjustments related to Quellos (1) (3 ) March 31, 2018 $ 13,217 (1) The decrease in goodwill during the three months ended March 31, 2018 resulted from a decline related to tax benefits realized from tax-deductible goodwill in excess of book goodwill from the acquisition of the fund-of-funds business of Quellos Group, LLC in October 2007 (the “Quellos Transaction”). Goodwill related to the Quellos Transaction will continue to be reduced in future periods by the amount of tax benefits realized from tax-deductible goodwill in excess of book goodwill from the Quellos Transaction. The balance of the Quellos tax-deductible goodwill in excess of book goodwill was approximately $161 million and $168 million at March 31, 2018 and December 31, 2017, respectively.

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Carrying Amounts of Identifiable Intangible Assets	The carrying amounts of identifiable intangible assets are summarized as follows: (in millions) Indefinite-lived Finite-lived Total December 31, 2017 $ 17,178 $ 211 $ 17,389 Amortization expense — (11 ) (11 ) March 31, 2018 $ 17,178 $ 200 $ 17,378

Borrowings (Tables)

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Carrying Value and Fair Value of Long-Term Borrowings	The carrying value and fair value of long-term borrowings estimated using market prices and foreign exchange rates at March 31, 2018 included the following: (in millions) Maturity Amount Unamortized Discount and Debt Issuance Costs Carrying Value Fair Value 5.00% Notes due 2019 $ 1,000 $ — $ 1,000 $ 1,039 4.25% Notes due 2021 750 (2 ) 748 774 3.375% Notes due 2022 750 (4 ) 746 759 3.50% Notes due 2024 1,000 (6 ) 994 1,006 1.25% Notes due 2025 861 (6 ) 855 877 3.20% Notes due 2027 700 (7 ) 693 679 Total Long-term Borrowings $ 5,061 $ (25 ) $ 5,036 $ 5,134

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue From Contract With Customer [Abstract]
Summary of Investment Advisory, Administration Fees and Securities Lending Revenue and Performance Fees by Type	The table below presents the Company’s revenue for the three months ended March 31, 2018 and 2017, respectively, and disaggregates investment advisory, administration fees and securities lending revenue and performance fees by product type and investment style. See Note 2, Significant Accounting Policies Three Months Ended March 31, (in millions) 2018 2017 Investment advisory, administration fees and securities lending revenue: Equity: Active $ 438 $ 400 iShares ETFs 926 721 Non-ETF index 176 160 Equity subtotal 1,540 1,281 Fixed income: Active 456 407 iShares ETFs 208 185 Non-ETF index 93 85 Fixed income subtotal 757 677 Multi-asset 296 272 Alternatives: Core 178 144 Currency and commodities 25 22 Alternatives subtotal 203 166 Long-term 2,796 2,396 Cash management 151 127 Total base fees 2,947 2,523 Investment advisory performance fees: Equity 18 15 Fixed income 3 10 Multi-asset 5 5 Alternatives 44 40 Total performance fees 70 70 Technology and risk management revenue 184 154 Distribution fees: Retrocessions 192 155 12b-1 fees (U.S. mutual funds distribution fees) 108 122 Other 11 10 Total distribution fees 311 287 Advisory and other revenue Advisory 21 24 Other 50 34 Advisory and other revenue 71 58 Total revenue $ 3,583 $ 3,092 The table below presents the investment advisory, administration fees and securities lending revenue by client type, investment style and product type, respectively: For the Three Months Ended March 31, (in millions) 2018 2017 Investment advisory, administration fees and securities lending revenue by client type: Retail $ 855 $ 776 iShares ETFs 1,158 925 Institutional: Active 527 458 Index 256 237 Total institutional 783 695 Long-term 2,796 2,396 Cash management 151 127 Total $ 2,947 $ 2,523 Investment advisory, administration fees and securities lending revenue by investment style: Active $ 1,365 $ 1,220 Index and iShares 1,431 1,176 Long-term 2,796 2,396 Cash management 151 127 Total $ 2,947 $ 2,523 Investment advisory, administration fees and securities lending revenue by product type: Equity $ 1,540 $ 1,281 Fixed income 757 677 Multi-asset 296 272 Alternatives 203 166 Long-term 2,796 2,396 Cash management 151 127 Total $ 2,947 $ 2,523
Schedule of Estimated Investment Advisory, Administration Fees Expected to be Recognized in Future, Related to Unsatisfied Portion of Performance Obligations	The table below presents estimated investment advisory and administration fees expected to be recognized in the future related to the unsatisfied portion of the performance obligations at March 31, 2018: Remainder of (in millions) 2018 2019 2020 2021 Thereafter Total Investment advisory and administration fees: Alternatives (1)(2) $ 61 $ 70 $ 58 $ 48 $ 48 $ 285 (1) Investment advisory and administration fees include management fees related to certain alternative products, which are based on contractual committed capital outstanding at March 31, 2018. Actual management fees could be higher to the extent additional committed capital is raised. These fees are generally billed on a quarterly basis in arrears. The Company excludes fees that are probable of significant reversal in future periods. (2) The Company elected the following practical expedients and does not include amounts related to (1) performance obligations with an original duration of one year or less, (2) variable consideration related to future service periods, and (3) the comparative prior period as of March 31, 2017.
Schedule of Changes in Deferred Carried Interest Liability	The table below presents changes in the deferred carried interest liability (including the portion related to consolidated VIEs) for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, (in millions) 2018 2017 Beginning balance $ 219 $ 152 Net increase (decrease) in unrealized allocations 5 9 Performance fee revenue recognized that was included in the deferred carried interest liability balance at the beginning of the period — (10 ) Ending balance $ 224 $ 151
Schedule of Estimated Technology and Risk Management Revenue Expected to Be Recognized in Future, Related to Unsatisfied Portion of Performance Obligations	The table below presents estimated technology and risk management revenue expected to be recognized in the future related to the unsatisfied portion of the performance obligations at March 31, 2018: Remainder of (in millions) 2018 2019 2020 2021 Thereafter Total Technology and risk management revenue (1)(2) $ 25 $ 24 $ 20 $ 15 $ 10 $ 94 (1) Technology and risk management revenue primarily includes upfront payments from customers, which the Company generally recognizes as services are performed. The Company excludes fees that are probable of significant reversal in future periods. (2) The Company elected the following practical expedients and does not include amounts related to (1) performance obligations with an original duration of one year or less, (2) variable consideration related to future service periods, and (3) the comparative prior period as of March 31, 2017.
Schedule of Changes in Technology and Risk Management Deferred Revenue Liability	The table below presents changes in the technology and risk management deferred revenue liability for the three months ended March 31, 2018 and 2017, which is included in other liabilities on the condensed consolidated statements of financial condition: Three Months Ended March 31, (in millions) 2018 2017 Beginning balance $ 62 $ 42 Additions 12 8 Amount recognized included in the deferred revenue liability beginning balance (8 ) (4 ) Ending balance $ 66 $ 46

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Restricted Stock and RSU Activity	Restricted stock and restricted stock units (“RSUs”) activity for the three months ended March 31, 2018 is summarized below. Outstanding at Restricted Stock and RSUs Weighted- Average Grant Date Fair Value December 31, 2017 2,608,668 $ 342.79 Granted 753,901 $ 565.83 Converted (1,071,338 ) $ 336.95 Forfeited (6,721 ) $ 408.89 March 31, 2018 (1) 2,284,510 $ 418.94 (1) At March 31, 2018, approximately 2.1 million awards are expected to vest and 0.2 million awards have vested but have not been converted.
Performance-Based RSUs [Member]
Restricted Stock and RSU Activity	Performance-based RSU activity for the three months ended March 31, 2018 is summarized below. Outstanding at Performance- Based RSUs Weighted- Average Grant Date Fair Value December 31, 2017 903,525 $ 335.12 Granted 199,068 $ 566.44 Additional shares granted due to attainment of performance measures 23,376 $ 343.86 Converted (269,648 ) $ 343.86 March 31, 2018 856,321 $ 386.38
Market Performance-Based RSUs [Member]
Restricted Stock and RSU Activity	Market performance-based RSUs activity for the three months ended March 31, 2018 is summarized below. Outstanding at Market Performance- Based RSUs Weighted- Average Grant Date Fair Value December 31, 2017 286,336 $ 195.33 Converted (286,336 ) $ 195.33 March 31, 2018 — $ —
Performance-Based Stock Options [Member]
Stock Option Activity	Stock option activity for the three months ended March 31, 2018 is summarized below Outstanding at Shares Under Option Weighted Average Exercise Price December 31, 2017 2,147,562 $ 513.50 Granted — $ — March 31, 2018 2,147,562 $ 513.50

Accumulated Other Comprehensi43

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income (Loss)	The following tables present changes in accumulated other comprehensive income (loss) (“AOCI”) by component for the three months ended March 31, 2018 and 2017: (in millions) Foreign currency translation adjustments (1) Other (2) Total For the Three Months Ended March 31, 2018 December 31, 2017 $ (436 ) $ 4 $ (432 ) Net other comprehensive income (loss) for the three months ended March 31, 2018 137 — 137 Reclassification as a result of adoption of ASU 2018-02 (6 ) — (6 ) March 31, 2018 $ (305 ) $ 4 $ (301 ) (1) Amount for the three months ended March 31, 2018 includes a loss from a net investment hedge of $16 million (net of a tax benefit of $5 million) and reclassification as a result of adoption of ASU 2018-02. (2) (in millions) Foreign currency translation adjustments (1) Other (2) Total For the Three Months Ended March 31, 2017 December 31, 2016 $ (721 ) $ 5 $ (716 ) Net other comprehensive income (loss) for the three months ended March 31, 2017 40 (1 ) 39 March 31, 2017 $ (681 ) $ 4 $ (677 ) ( 1) (2)

Capital Stock (Tables)

Capital Stock (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Preferred Shares Authorized, Issued and Outstanding	Nonvoting Participating Preferred Stock . The Company’s preferred shares authorized, issued and outstanding consisted of the following: March 31, December 31, 2018 2017 Series A Shares authorized, $0.01 par value 20,000,000 20,000,000 Shares issued and outstanding — — Series B Shares authorized, $0.01 par value 150,000,000 150,000,000 Shares issued and outstanding (1) 823,188 823,188 Series C Shares authorized, $0.01 par value 6,000,000 6,000,000 Shares issued and outstanding (1) 143,458 246,522 Series D Shares authorized, $0.01 par value 20,000,000 20,000,000 Shares issued and outstanding — — (1) Shares held by PNC.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted EPS under Treasury Stock Method	The following table sets forth the computation of basic and diluted EPS for the three months ended March 31, 2018 and 2017 under the treasury stock method: Three Months Ended March 31, (in millions, except shares and per share data) 2018 2017 Net income attributable to BlackRock $ 1,089 $ 859 Basic weighted-average shares outstanding 161,250,018 163,016,599 Dilutive effect of nonparticipating RSUs and stock options 1,668,943 1,839,584 Total diluted weighted-average shares outstanding 162,918,961 164,856,183 Basic earnings per share $ 6.75 $ 5.27 Diluted earnings per share $ 6.68 $ 5.21

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Total Revenue by Geographic Region	The following table illustrates total revenue for the three months ended March 31, 2018 and 2017 by geographic region. These amounts are aggregated on a legal entity basis and do not necessarily reflect where the customer resides or affiliated services are provided. Three Months Ended (in millions) March 31, Revenue 2018 2017 Americas $ 2,324 $ 2,043 Europe 1,093 906 Asia-Pacific 166 143 Total revenue $ 3,583 $ 3,092
Schedule of Long-Lived Assets by Geographic Region	The following table illustrates long-lived assets that consist of goodwill and property and equipment at March 31, 2018 and December 31, 2017 by geographic region. These amounts are aggregated on a legal entity basis and do not necessarily reflect where the asset is physically located. See Note 13, Revenue (in millions) March 31, December 31, Long-lived Assets 2018 2017 Americas $ 13,551 $ 13,560 Europe 172 168 Asia-Pacific 83 84 Total long-lived assets $ 13,806 $ 13,812

Business Overview - Additional

Business Overview - Additional Information (Detail) - PNC [Member]	Mar. 31, 2018
Related Party Transaction [Line Items]
Percentage of common stock of parent owned	21.20%
Percentage of capital stock of parent owned	21.70%

Significant Accounting Polici48

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Other assets	$ 2,157		$ 1,636
Other liabilities	2,130		1,626
Fair value of loaned securities	24,800		22,300
Fair value of collateral held for loan securities	$ 27,247		24,190
Minimum [Member]
Significant Accounting Policies [Line Items]
Collateral cash and securities received in exchange of value of securities lent in order to reduce counterparty risk	102.00%
Maximum [Member]
Significant Accounting Policies [Line Items]
Collateral cash and securities received in exchange of value of securities lent in order to reduce counterparty risk	112.00%
Consolidated VIEs [Member]
Significant Accounting Policies [Line Items]
Deferred carried interest, contract liability	$ 224		$ 219
Accounting Standards Update 2014-09 [Member] | Adoption of the New Revenue Standard Adjustment [Member]
Significant Accounting Policies [Line Items]
Other assets		$ 19
Other liabilities		25
Net decrease in retained earnings		$ 6

Significant Accounting Polici49

Significant Accounting Policies - Impact of ASU 2014-09 Adoption to Condensed Consolidated Statement of Income (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Significant Accounting Policies [Line Items]
Total revenue	$ 3,583	$ 3,092
Total expense	2,208	1,949
Operating income	1,375	1,143
Income tax expense	265	268
Net income	1,094	868
Net income attributable to BlackRock, Inc.	$ 1,089	$ 859
Earnings per share attributable to BlackRock, Inc. common stockholders:
Basic	$ 6.75	$ 5.27
Diluted	$ 6.68	$ 5.21
Accounting Standards Update 2014-09 [Member] | Previously Reported [Member]
Significant Accounting Policies [Line Items]
Total revenue		$ 2,824
Total expense		1,677
Operating income		1,147
Income tax expense		269
Net income		871
Net income attributable to BlackRock, Inc.		$ 862
Earnings per share attributable to BlackRock, Inc. common stockholders:
Basic		$ 5.29
Diluted		$ 5.23
Accounting Standards Update 2014-09 [Member] | Adoption of the New Revenue Standard Adjustment [Member]
Significant Accounting Policies [Line Items]
Total revenue		$ 268
Total expense		272
Operating income		(4)
Income tax expense		(1)
Net income		(3)
Net income attributable to BlackRock, Inc.		$ (3)
Earnings per share attributable to BlackRock, Inc. common stockholders:
Basic		$ (0.02)
Diluted		$ (0.02)

Cash, Cash Equivalents and Re50

Cash, Cash Equivalents and Restricted Cash - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Restricted Cash And Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 5,978	$ 6,894
Total cash, cash equivalents and restricted cash	6,143	7,096	$ 5,831	$ 6,192
Consolidated Variable Interest Entities [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Cash and cash equivalents	103	144
Other Assets [Member]
Restricted Cash And Cash Equivalents Items [Line Items]
Restricted cash included in Other assets	$ 62	$ 58

Investments - Summary of Carryi

Investments - Summary of Carrying Value of Total Investments (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Available-for-sale investments, Debt securities	$ 151
Available-for-sale investments		$ 103
Held-to-maturity investments	132	102
Trading securities ($266 debt securities of consolidated sponsored investment funds)	293
Total trading investments		835
Total debt securities	576
Equity securities at FVTNI ($284 equity securities of consolidated sponsored investment funds)	648
Total investments	2,050	1,981
Other Equity and Debt Securities [Member]
Investment [Line Items]
Total trading investments		267
Deferred Compensation Plan Fund [Member]
Investment [Line Items]
Total trading investments		56
Consolidated Sponsored Investment Funds [Member] | Debt securities [Member]
Investment [Line Items]
Total trading investments	266	267
Consolidated Sponsored Investment Funds [Member] | Equity securities [Member]
Investment [Line Items]
Total trading investments		245
Equity securities at FVTNI ($284 equity securities of consolidated sponsored investment funds)	284
Equity Method Investments [Member]
Investment [Line Items]
Total investments	703	816
Cost Method Investments [Member]
Investment [Line Items]
Total investments		93
Federal Reserve Bank Stock [Member]
Investment [Line Items]
Total investments	91
Consolidated Entities [Member] | Carried Interest [Member]
Investment [Line Items]
Total investments	$ 32	$ 32

Investments - Summary of Carr52

Investments - Summary of Carrying Value of Total Investments (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Total trading investments		$ 835
Equity securities	$ 648
Consolidated Sponsored Investment Funds [Member] | Debt securities [Member]
Investment [Line Items]
Total trading investments	266	267
Consolidated Sponsored Investment Funds [Member] | Equity securities [Member]
Investment [Line Items]
Total trading investments		$ 245
Equity securities	$ 284

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Held-to-maturity investments	$ 132	$ 102
Foreign government debt, after five years through ten years	12
Foreign government debt, after ten years	$ 120
PennyMac [Member]
Investment [Line Items]
Ownership percentage	20.00%	20.00%
Shares and units	16	16
Carrying value - equity method investment	$ 363	$ 342
Fair value of equity method investments	$ 352	$ 348

Investments - Summary of Cost a

Investments - Summary of Cost and Carrying Value of Equity and Trading Debt Securities (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Total trading investments, Cost		$ 760
Total equity and trading debt securities, Cost	$ 888
Total trading investments, Carrying Value		835
Total equity and trading debt securities, Carrying Value	941
Corporate Debt [Member]
Schedule of Investments [Line Items]
Total trading investments, Cost	166	152
Total trading investments, Carrying Value	169	157
Government Debt [Member]
Schedule of Investments [Line Items]
Total trading investments, Cost	62	72
Total trading investments, Carrying Value	62	73
Asset/Mortgage-Backed Debt [Member]
Schedule of Investments [Line Items]
Total trading investments, Cost	62	56
Total trading investments, Carrying Value	62	56
Deferred Compensation Plan Fund [Member]
Schedule of Investments [Line Items]
Total trading investments, Cost		34
Equity securities at FVTNI, Cost	21
Total trading investments, Carrying Value		56
Equity securities at FVTNI, Carrying Value	34
Equity Securities/Multi-Asset Mutual Funds [Member]
Schedule of Investments [Line Items]
Total trading investments, Cost		446
Equity securities at FVTNI, Cost	577
Total trading investments, Carrying Value		$ 493
Equity securities at FVTNI, Carrying Value	$ 614

Consolidated VREs Recorded in C

Consolidated VREs Recorded in Condensed Consolidated Statements of Financial Condition (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Consolidated Sponsored Investment Funds [Line Items]
Cash and cash equivalents	$ 5,978	$ 6,894
Investments:
Total trading investments		835
Equity securities	648
Total investments	2,050	1,981
Other assets	2,157	1,636
Other liabilities	(2,130)	(1,626)
Noncontrolling interests ("NCI")	(44)	(50)
Equity Securities/Multi-Asset Mutual Funds [Member]
Investments:
Total trading investments		493
Consolidated Voting Rights Entities [Member]
Consolidated Sponsored Investment Funds [Line Items]
Cash and cash equivalents	44	63
Investments:
Total trading investments	266	267
Total investments	550	512
Other assets	15	13
Other liabilities	(42)	(37)
Noncontrolling interests ("NCI")	(87)	(91)
BlackRock’s net interests in consolidated VREs	480	460
Consolidated Voting Rights Entities [Member] | Equity Securities/Multi-Asset Mutual Funds [Member]
Investments:
Equity securities	$ 284	$ 245

Variable Interest Entities Refl

Variable Interest Entities Reflects adoption of ASU 2015-12 - Schedule of VIE Assets and Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 5,978	$ 6,894
Investments:
Trading securities ($266 debt securities of consolidated sponsored investment funds)	293
Equity securities	648
Other assets	2,157	1,636
Liabilities of consolidated VIEs	(183,434)	(187,977)
Noncontrolling interests	(44)	(50)
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	103	144
Investments:
Trading securities ($266 debt securities of consolidated sponsored investment funds)	769	475
Equity securities	295	440
Other investments	300	312
Carried interest	273	266
Other assets	113	66
Total investments and other assets	1,750	1,559
Liabilities of consolidated VIEs	(425)	(369)
Noncontrolling interests	(518)	(375)
BlackRock's net interests in consolidated VIEs	$ 910	$ 959

Variable Interest Entities Re57

Variable Interest Entities Reflects adoption of ASU 2015-12 - Schedule of Net Gain (Loss) Related to Consolidated VIEs (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Variable Interest Entity [Line Items]
Nonoperating net gain (loss) on consolidated VIEs	$ 15	$ 51
Net income (loss) attributable to noncontrolling interests	5	9
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Nonoperating net gain (loss) on consolidated VIEs	2	33
Net income (loss) attributable to noncontrolling interests	$ 5	$ 8

Variable Interest Entities Re58

Variable Interest Entities Reflects adoption of ASU 2015-12 - Balances Relating to Variable Interest Entities in which BlackRock is Not Primary Beneficiary (Detail) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Investments [Member]
Variable Interest Entity [Line Items]
Sponsored investment products	$ 342,000,000	$ 263,000,000
Advisory Fee Receivables [Member]
Variable Interest Entity [Line Items]
Sponsored investment products	30,000,000	15,000,000
Other Net Assets (Liabilities) [Member]
Variable Interest Entity [Line Items]
Sponsored investment products	(7,000,000)	(7,000,000)
Maximum Risk of Loss [Member]
Variable Interest Entity [Line Items]
Sponsored investment products	$ 389,000,000	$ 295,000,000

Variable Interest Entities Re59

Variable Interest Entities Reflects adoption of ASU 2015-12 - Additional Information (Detail) - USD ($) $ in Billions	Mar. 31, 2018	Dec. 31, 2017
Variable Interest Entity, Not Primary Beneficiary [Member] | Sponsored Investment Products [Member]
Variable Interest Entity [Line Items]
Net assets of investments funds	$ 6	$ 5

Fair Value Disclosures - Assets

Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	$ 648
Total trading investments		$ 835
Available-for-sale		103
Separate account assets	142,871	149,937
Total separate account collateral held under securities lending agreements	27,247	24,190
Equity Securities/Multi-Asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total trading investments		493
Investments Measured At NAV [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	62	70
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity securities	648
Total debt securities	576
Total trading investments		835
Held-to-maturity securities	132	102
Available-for-sale		103
Total equity method	703	816
Federal Reserve Bank Stock	91
Cost method investments		93
Carried interest	32	32
Total investments	2,050	1,981
Total investments of consolidated VIEs	1,637	1,493
Other assets	35
Separate account assets	142,871	149,937
Total separate account collateral held under securities lending agreements	27,247	24,190
Total	173,840	177,601
Separate account collateral liabilities under securities lending agreements	27,247	24,190
Other liabilities	249	243
Total liabilities measured at fair value	27,496	24,433
Fair Value, Measurements, Recurring [Member] | Deferred Compensation Plan Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	34	56
Fair Value, Measurements, Recurring [Member] | Equity Securities/Multi-asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity securities	614
Total trading investments		493
Fair Value, Measurements, Recurring [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total trading investments	293	286
Fair Value, Measurements, Recurring [Member] | Equity And Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	131	195
Fair Value, Measurements, Recurring [Member] | Other Types Of Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	572	621
Total investments of consolidated VIEs	50	53
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	250	259
Fair Value, Measurements, Recurring [Member] | Equity Securities/Multi-Asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	295	440
Total separate account collateral held under securities lending agreements	18,543	18,778
Fair Value, Measurements, Recurring [Member] | Carried Interest [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	273	266
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	769	475
Total separate account collateral held under securities lending agreements	8,704	5,412
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity securities	648
Total trading investments		551
Available-for-sale		7
Total equity method	116	183
Total investments	764	741
Total investments of consolidated VIEs	298	446
Separate account assets	107,095	114,422
Total separate account collateral held under securities lending agreements	18,543	18,778
Total	126,700	134,387
Separate account collateral liabilities under securities lending agreements	18,543	18,778
Total liabilities measured at fair value	18,543	18,778
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Deferred Compensation Plan Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	34	56
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities/Multi-asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity securities	614
Total trading investments		493
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total trading investments		2
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity And Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	116	183
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	3	6
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities/Multi-Asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	295	440
Total separate account collateral held under securities lending agreements	18,543	18,778
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	413
Total trading investments		284
Available-for-sale		96
Total investments	413	380
Total investments of consolidated VIEs	772	477
Other assets	35
Separate account assets	35,063	34,582
Total separate account collateral held under securities lending agreements	8,704	5,412
Total	44,987	40,851
Separate account collateral liabilities under securities lending agreements	8,704	5,412
Other liabilities	7	7
Total liabilities measured at fair value	8,711	5,419
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total trading investments	288	284
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	3	2
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	769	475
Total separate account collateral held under securities lending agreements	8,704	5,412
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	31
Total investments	31
Total investments of consolidated VIEs	116	116
Total	147	116
Other liabilities	242	236
Total liabilities measured at fair value	242	236
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total trading investments	5
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	116	116
Fair Value, Measurements, Recurring [Member] | Available-for-sale [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	151
Fair Value, Measurements, Recurring [Member] | Available-for-sale [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	125
Fair Value, Measurements, Recurring [Member] | Available-for-sale [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	26
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	584	621
Total investments	584	621
Total investments of consolidated VIEs	106	112
Total	690	733
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member] | Equity And Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	15	12
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member] | Other Types Of Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	569	609
Total investments of consolidated VIEs	50	53
Fair Value, Measurements, Recurring [Member] | Investments Measured At NAV [Member] | Investment in NAV [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	56	59
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	132
Held-to-maturity securities	132	102
Total equity method	3	12
Federal Reserve Bank Stock	91
Cost method investments		93
Carried interest	32	32
Total investments	258	239
Total investments of consolidated VIEs	345	342
Separate account assets	712	933
Total	1,315	1,514
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member] | Other Types Of Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	3	12
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	72	76
Fair Value, Measurements, Recurring [Member] | Other Assets Not Held at Fair Value [Member] | Carried Interest [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments of consolidated VIEs	$ 273	$ 266

Fair Value Disclosures - Additi

Fair Value Disclosures - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Significant Unobservable Inputs (Level 3) [Member] | Private/ Public Equity [Member] | Consolidated Variable Interest Entities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total investments	$ 116	$ 116

Fair Value Disclosures - Change

Fair Value Disclosures - Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value, beginning balance	$ 116	$ 143
Realized and Unrealized Gains (Losses) in Earnings and OCI, Assets		1
Purchases, Assets	31
Transfers out of Level 3, Assets		(31)
Assets measured at fair value, ending balance	147	113
Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value, beginning balance		24
Purchases, Assets	26
Transfers out of Level 3, Assets		(24)
Assets measured at fair value, ending balance	26
Consolidated Variable Interest Entities [Member] | Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liabilities measured at fair value, beginning balance	236	115
Realized and Unrealized Gains (Losses) in Earnings and OCI, Liabilities	(6)	2
Liabilities measured at fair value, ending balance	242	113
Total Net Unrealized Gains (Losses) Included in Earnings	(6)	2
Consolidated Variable Interest Entities [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value, beginning balance	116	112
Realized and Unrealized Gains (Losses) in Earnings and OCI, Assets		1
Assets measured at fair value, ending balance	116	113
Total Net Unrealized Gains (Losses) Included in Earnings		1
Trading Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value, beginning balance		7
Purchases, Assets	5
Transfers out of Level 3, Assets		(7)
Assets measured at fair value, ending balance	5
Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value, beginning balance		31
Purchases, Assets	31
Transfers out of Level 3, Assets		$ (31)
Assets measured at fair value, ending balance	$ 31

Fair Value Disclosures - Fair V

Fair Value Disclosures - Fair Value of Financial Assets and Financial Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 5,978	$ 6,894
Long-term borrowings	5,036	5,014
Consolidated Variable Interest Entities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	103	144
Carrying Amount [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	5,978	6,894
Other assets	62	70
Carrying Amount [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings	5,036	5,014
Carrying Amount [Member] | Consolidated Variable Interest Entities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	103	144
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	5,978	6,894
Other assets	62	70
Estimated Fair Value [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings	5,134	5,225
Estimated Fair Value [Member] | Consolidated Variable Interest Entities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 103	$ 144

Fair Value Disclosures - Fair64

Fair Value Disclosures - Fair Value of Financial Assets and Financial Liabilities (Parenthetical) (Detail) - USD ($) $ / shares in Units, $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 5,978	$ 6,894
Money market valuation per share floor	$ 1
Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 204	163
Consolidated Variable Interest Entities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	103	144
Consolidated Variable Interest Entities [Member] | Money Market Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 13	$ 14

Fair Value Disclosures - Invest

Fair Value Disclosures - Investments in Certain Entities Calculate Net Asset Value per Share (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 690	$ 733
Total Unfunded Commitments	309	286
Hedge Funds/Funds of Hedge Funds [Member] | Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 14	$ 19
Hedge Funds/Funds of Hedge Funds [Member] | Maximum [Member] | Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	90 days	90 days
Real Assets Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 128	$ 117
Real Assets Funds [Member] | Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	36	34
Total Unfunded Commitments	48	49
Private Equity Funds Of Funds [Member] | Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	56	59
Total Unfunded Commitments	18	20
Equity Method Investments [Member] | Hedge Funds/Funds of Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	168	230
Total Unfunded Commitments	$ 64	$ 48
Redemption Frequency (Daily)	30.00%	21.00%
Redemption Frequency (Monthly)	30.00%	21.00%
Redemption Frequency (Quarterly)	29.00%	49.00%
Redemption Frequency (Not Redeemable)	41.00%	30.00%
Equity Method Investments [Member] | Hedge Funds/Funds of Hedge Funds [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	1 day	1 day
Equity Method Investments [Member] | Hedge Funds/Funds of Hedge Funds [Member] | Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	90 days	90 days
Equity Method Investments [Member] | Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 99	$ 94
Total Unfunded Commitments	85	86
Equity Method Investments [Member] | Real Assets Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	302	282
Total Unfunded Commitments	$ 79	$ 69
Redemption Frequency (Quarterly)	78.00%	83.00%
Redemption Frequency (Not Redeemable)	22.00%	17.00%
Redemption Notice Period, Not Redeemable	60 days	60 days
Equity Method Investments [Member] | Real Assets Funds [Member] | Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days		60 days
Equity Method Investments [Member] | Other Types Of Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 15	$ 15
Total Unfunded Commitments	$ 15	$ 14
Redemption Frequency (Daily)	79.00%	80.00%
Redemption Frequency (Monthly)	79.00%
Redemption Frequency (Not Redeemable)	21.00%	20.00%
Equity Method Investments [Member] | Other Types Of Investments [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	3 days
Equity Method Investments [Member] | Other Types Of Investments [Member] | Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption Notice Period, days	5 days	5 days

Fair Value Disclosures - Inve66

Fair Value Disclosures - Investments in Certain Entities Calculate Net Asset Value per Share (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 309	$ 286
Hedge Funds/Funds of Hedge Funds [Member] | Equity Method Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Liquidation period, years	7 years	7 years
Total Unfunded Commitments	$ 64	$ 48
Private Equity Funds [Member] | Equity Method Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Liquidation period, years	6 years	6 years
Total Unfunded Commitments	$ 85	$ 86
Real Assets Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	128	117
Amount of unfunded commitments contractually obligated to fund	108	98
Real Assets Funds [Member] | Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Unfunded Commitments	$ 48	$ 49
Real Assets Funds [Member] | Equity Method Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Redemption period	8 years	8 years
Total Unfunded Commitments	$ 79	$ 69
Private Equity Funds Of Funds [Member] | Consolidated Variable Interest Entities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Liquidation period, years	5 years		5 years
Total Unfunded Commitments	$ 18	20
Amount of unfunded commitments contractually obligated to fund	$ 23	$ 23

Derivatives and Hedging - Addit

Derivatives and Hedging - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative maximum risk of loss for credit protection	$ 17		$ 17
Forward Foreign Currency Exchange Contracts [Member]
Derivative [Line Items]
Notional value	1,500		1,500
Fair value of the outstanding forward foreign currency exchange contracts	35
Other General and Administration Expense [Member]
Derivative [Line Items]
Foreign currency translation gains (losses)	30
Total Return Swaps [Member]
Derivative [Line Items]
Notional value	$ 546		$ 587
Total Return Swaps [Member] | Nonoperating Income (Expense) [Member]
Derivative [Line Items]
Amount of gains (losses) recognized in income on derivative instruments		$ (35)

Goodwill - Goodwill Activity (D

Goodwill - Goodwill Activity (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Goodwill Roll Forward
Beginning balance	$ 13,220
Goodwill adjustment related to Quellos	(3)
Ending balance	$ 13,217

Goodwill - Goodwill Activity (P

Goodwill - Goodwill Activity (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Excess of tax goodwill over book goodwill	$ 161	$ 168

Intangible Assets - Carrying Am

Intangible Assets - Carrying Amounts of Identifiable Intangible Assets (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Indefinite-lived intangible assets, Beginning balance	$ 17,178
Indefinite-lived intangible assets, Ending balance	17,178
Finite-lived intangible assets, Beginning balance	211
Finite-lived intangible assets, amortization expense	(11)	$ (25)
Finite-lived intangible assets, Ending balance	200
Intangible assets, Beginning balance	17,389
Intangible assets, Ending balance	$ 17,378

Borrowings - Additional Informa

Borrowings - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)
Commercial Paper [Member]
Debt Instrument [Line Items]
Maximum amount available under facility	$ 4,000,000,000
Amount outstanding under credit facility	0
2018 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Unsecured revolving credit facility	4,000,000,000
Additional amount available, subject to lender credit approval	1,000,000,000
Maximum amount available under facility	5,000,000,000
Amount outstanding under credit facility	$ 0
Extended debt instrument maturity date	2023-03
Line of credit facility, covenant terms	The 2018 credit facility requires the Company not to exceed a maximum 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 to 1
Line of credit facility, covenant compliance	satisfied with a ratio of less than 1 to 1

Borrowings - Carrying Value and

Borrowings - Carrying Value and Fair Value of Long-Term Borrowings (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Maturity Amount	$ 5,061
Unamortized Discount and Debt Issuance Costs	(25)
Carrying Value	5,036	$ 5,014
Fair Value	5,134
5.00% Notes due 2019 [Member]
Debt Instrument [Line Items]
Maturity Amount	1,000
Carrying Value	1,000
Fair Value	1,039
4.25% Notes due 2021 [Member]
Debt Instrument [Line Items]
Maturity Amount	750
Unamortized Discount and Debt Issuance Costs	(2)
Carrying Value	748
Fair Value	774
3.375% Notes due 2022 [Member]
Debt Instrument [Line Items]
Maturity Amount	750
Unamortized Discount and Debt Issuance Costs	(4)
Carrying Value	746
Fair Value	759
3.50% Notes due 2024 [Member]
Debt Instrument [Line Items]
Maturity Amount	1,000
Unamortized Discount and Debt Issuance Costs	(6)
Carrying Value	994
Fair Value	1,006
1.25% Notes due 2025 [Member]
Debt Instrument [Line Items]
Maturity Amount	861
Unamortized Discount and Debt Issuance Costs	(6)
Carrying Value	855
Fair Value	877
3.20% Notes due 2027 [Member]
Debt Instrument [Line Items]
Maturity Amount	700
Unamortized Discount and Debt Issuance Costs	(7)
Carrying Value	693
Fair Value	$ 679

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Mar. 16, 2016Person	Mar. 31, 2018USD ($)ft²	Dec. 31, 2017USD ($)
Commitment And Contingencies [Line Items]
Various capital commitments to fund sponsored investment funds, including funds of private equity funds, real assets funds, opportunistic funds and distressed credit funds		$ 304
Derivative maximum risk of loss for credit protection		17	$ 17
Number of former tenants suing BlackRock Parties | Person	3
Securities lending loan balances indemnified		219,000
Collateral for indemnified securities		$ 232,000
Employee 401(k) Plan [Member]
Commitment And Contingencies [Line Items]
Description of claim sought by former employee under lawsuit complaint		While the complaint does not contain any specific amount in alleged damages, it claims that the purported underperformance and hidden fees cost Plan participants more than $60 million
Employee 401(k) Plan [Member] | Minimum [Member]
Commitment And Contingencies [Line Items]
Purported underperformance and hidden fees cost		$ 60
Other Liabilities [Member]
Commitment And Contingencies [Line Items]
Contingent consideration at fair value		$ 242
Operating Lease [Member]
Commitment And Contingencies [Line Items]
Area of office space | ft²		847,000
Operating leases, term of contract		20 years
Expected lease commencement date		May 31, 2023
Annual base rental payments first five years		$ 51
Annual base rental payments five to ten years		58
Annual base rental payments ten to fifteen years		66
Annual base rental payments fifteen to twenty years		74
Total operating lease minimum commitments		$ 1,200

Revenue - Summary of Investment

Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue and Performance Fees by Type (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	$ 2,947	$ 2,523
Investment advisory performance fees	70	70
Technology and risk management revenue	184	154
Distribution fees	311	287
Advisory and other revenue	71	58
Total revenue	3,583	3,092
Equity [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,540	1,281
Investment advisory performance fees	18	15
Equity [Member] | Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	438	400
Equity [Member] | iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	926	721
Equity [Member] | Non-ETF Index [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	176	160
Fixed Income [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	757	677
Investment advisory performance fees	3	10
Fixed Income [Member] | Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	456	407
Fixed Income [Member] | iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	208	185
Fixed Income [Member] | Non-ETF Index [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	93	85
Multi-asset [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	296	272
Investment advisory performance fees	5	5
Alternatives [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	203	166
Investment advisory performance fees	44	40
Alternatives [Member] | Core [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	178	144
Alternatives [Member] | Currency and Commodities [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	25	22
Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Retrocessions [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Distribution fees	192	155
12b-1 Fees (U.S. Mutual Funds Distribution Fees) [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Distribution fees	108	122
Other Distribution Fees [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Distribution fees	11	10
Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Advisory [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Advisory and other revenue	21	24
Other [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Advisory and other revenue	$ 50	$ 34

Revenue - Summary of Investme75

Revenue - Summary of Investment Advisory, Administration Fees and Securities Lending Revenue by Client Type, Investment Style and Product Type (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	$ 2,947	$ 2,523
Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Equity [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,540	1,281
Equity [Member] | Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	438	400
Equity [Member] | iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	926	721
Fixed Income [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	757	677
Fixed Income [Member] | Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	456	407
Fixed Income [Member] | iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	208	185
Multi-asset [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	296	272
Alternatives [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	203	166
Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Revenue by Client Type [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,947	2,523
Revenue by Client Type [Member] | Retail
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	855	776
Revenue by Client Type [Member] | iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,158	925
Revenue by Client Type [Member] | Institutional [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	783	695
Revenue by Client Type [Member] | Institutional [Member] | Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	527	458
Revenue by Client Type [Member] | Institutional [Member] | Index [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	256	237
Revenue by Client Type [Member] | Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Revenue by Client Type [Member] | Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Revenue by Investment Style [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,947	2,523
Revenue by Investment Style [Member] | Active [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,365	1,220
Revenue by Investment Style [Member] | Index and iShares ETFs [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,431	1,176
Revenue by Investment Style [Member] | Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Revenue by Investment Style [Member] | Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,796	2,396
Revenue by Product Type [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	2,947	2,523
Revenue by Product Type [Member] | Cash Management [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	151	127
Revenue by Product Type [Member] | Equity [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	1,540	1,281
Revenue by Product Type [Member] | Fixed Income [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	757	677
Revenue by Product Type [Member] | Multi-asset [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	296	272
Revenue by Product Type [Member] | Alternatives [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	203	166
Revenue by Product Type [Member] | Long-term [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Total investment advisory, administration fees and securities lending revenue	$ 2,796	$ 2,396

Revenue - Schedule of Estimated

Revenue - Schedule of Estimated Investment Advisory, Administration Fees Expected to be Recognized in Future, Related to Unsatisfied Portion of Performance Obligations (Detail) - Alternatives [Member] $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-04-01
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	9 months
Revenue, Remaining Performance Obligation	$ 61
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation	$ 70
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation	$ 58
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation	$ 48
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Revenue, Remaining Performance Obligation	$ 48
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: (nil)
Schedule of Investment Advisory Administration Fees and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation	$ 285

Revenue - Schedule of Changes i

Revenue - Schedule of Changes in Deferred Carried Interest Liability (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue From Contract With Customer [Abstract]
Beginning balance	$ 219	$ 152
Net increase (decrease) in unrealized allocations	5	9
Performance fee revenue recognized that was included in the deferred carried interest liability balance at the beginning of the period		(10)
Ending balance	$ 224	$ 151

Revenue - Schedule of Estimat78

Revenue - Schedule of Estimated Technology and Risk Management Revenue Expected to Be Recognized in Future, Related to Unsatisfied Portion of Performance Obligations (Detail) - Technology And Risk Management Revenue $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-04-01
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	9 months
Revenue, Remaining Performance Obligation	$ 25
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation	$ 24
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation	$ 20
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation	$ 15
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period
Revenue, Remaining Performance Obligation	$ 10
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: (nil)
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Revenue, Remaining Performance Obligation	$ 94

Revenue - Additional Informatio

Revenue - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Estimated annual fixed minimum fees for currently outstanding contracts	$ 348
Minimum [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Term of currently outstanding contracts	1 year
Maximum [Member]
Schedule of Investment Advisory Administration Fees and Securities Lending Revenue and Performance Fees by Type [line Items]
Term of currently outstanding contracts	5 years

Revenue - Schedule of Changes80

Revenue - Schedule of Changes in Technology and Risk Management Deferred Revenue Liability (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue From Contract With Customer [Abstract]
Beginning balance	$ 62	$ 42
Additions	12	8
Amount recognized included in the deferred revenue liability beginning balance	(8)	(4)
Ending balance	$ 66	$ 46

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock and RSU Activity (Detail) - $ / shares	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, beginning of period	2,608,668	2,608,668
Restricted Stock and RSUs, Granted		753,901
Restricted Stock and RSUs, Converted		(1,071,338)
Restricted Stock and RSUs, Forfeited		(6,721)
Restricted Stock and RSUs, end of period		2,284,510
Weighted-Average Grant Date Fair Value, beginning of period	$ 342.79	$ 342.79
Weighted-Average Grant Date Fair Value, Granted		565.83
Weighted-Average Grant Date Fair Value, Converted		336.95
Weighted-Average Grant Date Fair Value, Forfeited		408.89
Weighted-Average Grant Date Fair Value, end of period		$ 418.94
Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, beginning of period	903,525	903,525
Restricted Stock and RSUs, Granted	199,068	199,068
Restricted Stock and RSUs, Additional Grants	23,376	23,376
Restricted Stock and RSUs, Converted		(269,648)
Restricted Stock and RSUs, end of period		856,321
Weighted-Average Grant Date Fair Value, beginning of period	$ 335.12	$ 335.12
Weighted-Average Grant Date Fair Value, Granted		566.44
Weighted-Average Grant Date Fair Value, Additional Grants		343.86
Weighted-Average Grant Date Fair Value, Converted		343.86
Weighted-Average Grant Date Fair Value, end of period		$ 386.38
Market Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, beginning of period	286,336	286,336
Restricted Stock and RSUs, Converted		(286,336)
Weighted-Average Grant Date Fair Value, beginning of period	$ 195.33	$ 195.33
Weighted-Average Grant Date Fair Value, Converted		$ 195.33

Stock-Based Compensation - Re82

Stock-Based Compensation - Restricted Stock and RSU Activity (Parenthetical) (Detail) shares in Millions	Mar. 31, 2018shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation awards expected to vest	2.1
Awards vested, not converted	0.2

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, Granted		753,901
Fair value of RSUs/restricted stock granted to employees		$ 427
RSUs/Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, Granted	527,337
Award vesting period, years	3 years
Awards to employees cliff vesting	209,201
RSUs to employees that cliff vest, percentage	100.00%
RSUs to employees that cliff vest, date	Jan. 31, 2021
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of outstanding RSUs		$ 1,200
Stock price		$ 541.72
Unrecognized stock-based compensation expense		$ 575
Remaining weighted-average period		1 year 6 months
Performance-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock and RSUs, Granted	199,068	199,068
Award vesting period, years	3 years
Awards to employees cliff vesting	199,068
RSUs to employees that cliff vest, percentage	100.00%
RSUs to employees that cliff vest, date	Jan. 31, 2021
Intrinsic value of outstanding RSUs		$ 464
Stock price		$ 541.72
Unrecognized stock-based compensation expense		$ 203
Remaining weighted-average period		1 year 8 months 12 days
Restricted Stock and RSUs, Additional Grants	23,376	23,376
Fair value of RSUs/restricted stock granted to employees		$ 121
Long-Term Incentive Plans Funded by PNC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares surrendered		3,900,000
Number of additional shares surrendered		103,064
Remaining shares committed by PNC for long-term incentive awards		100,000
Long-Term Incentive Plans Funded by PNC [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares committed to fund long-term incentive plans		4,000,000
Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense		$ 191
Remaining weighted-average period		5 years 8 months 12 days

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Detail) - Performance-Based Stock Options [Member]	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Shares Under Option, Beginning of Period | shares	2,147,562
Granted, Shares Under Option | shares	0
Outstanding, Shares Under Option, End of Period | shares	2,147,562
Weighted Average Exercise Price, Beginning of Period | $ / shares	$ 513.50
Granted, Weighted Average Exercise Price | $ / shares	0
Weighted Average Exercise Price, End of Period | $ / shares	$ 513.50

Net Capital Requirements - Addi

Net Capital Requirements - Additional Information (Detail) $ in Billions	Mar. 31, 2018USD ($)
Regulatory Capital Requirements [Abstract]
Net capital requirement in certain regulated subsidiaries	$ 2.1

Accumulated Other Comprehensi86

Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 31,848	$ 29,140
Other comprehensive income (loss)	137	39
Balance	32,022	29,193
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(436)	(721)
Other comprehensive income (loss)	137	40
Reclassification as a result of adoption of ASU 2018-02	(6)
Balance	(305)	(681)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	4	5
Other comprehensive income (loss)		(1)
Balance	4	4
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(432)	(716)
Other comprehensive income (loss)	137	39
Reclassification as a result of adoption of ASU 2018-02	(6)
Balance	$ (301)	$ (677)

Accumulated Other Comprehensi87

Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Amounts Reclassified Out Of Accumulated Other Comprehensive Income Loss [Abstract]
Loss from net investment hedging, net of tax	$ (16)	$ (7)
Loss from net investment hedging, tax	$ (5)	$ (4)

Capital Stock - Preferred Share

Capital Stock - Preferred Shares Authorized, Issued and Outstanding (Detail) - shares	Mar. 31, 2018	Dec. 31, 2017
Series A Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Shares authorized, $0.01 par value	20,000,000	20,000,000
Shares issued	0	0
Shares outstanding	0	0
Series B Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Shares authorized, $0.01 par value	150,000,000	150,000,000
Shares issued	823,188	823,188
Shares outstanding	823,188	823,188
Series C Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Shares authorized, $0.01 par value	6,000,000	6,000,000
Shares issued	143,458	246,522
Shares outstanding	143,458	246,522
Series D Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Shares authorized, $0.01 par value	20,000,000	20,000,000
Shares issued	0	0
Shares outstanding	0	0

Capital Stock - Preferred Sha89

Capital Stock - Preferred Shares Authorized, Issued and Outstanding (Parenthetical) (Detail) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Series A Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value	$ 0.01	$ 0.01
Series B Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value	0.01	0.01
Series C Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value	0.01	0.01
Series D Nonvoting Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value	$ 0.01	$ 0.01

Capital Stock - Additional Info

Capital Stock - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Capitalization, Equity [Line Items]
Common shares repurchased	600,000
Common shares repurchased, value	$ 335	$ 275
Shares authorized to be repurchased	5,800,000
Series C Nonvoting Participating Preferred Stock [Member] | PNC [Member]
Schedule of Capitalization, Equity [Line Items]
Surrender of share of series non- voting preferred stock	103,064

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal statutory tax rate	21.00%		35.00%
Net tax benefit related to 2017 tax act	$ 1,200
Discrete income tax benefit for vested stock awards	$ 56	$ 81

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted EPS under Treasury Stock Method (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income attributable to BlackRock	$ 1,089	$ 859
Basic weighted-average shares outstanding	161,250,018	163,016,599
Dilutive effect of nonparticipating RSUs and stock options	1,668,943	1,839,584
Total diluted weighted-average shares outstanding	162,918,961	164,856,183
Basic earnings per share	$ 6.75	$ 5.27
Diluted earnings per share	$ 6.68	$ 5.21

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018Segment
Segment Reporting [Abstract]
Number of business segments	1

Segment Information - Total Rev

Segment Information - Total Revenue by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 3,583	$ 3,092
Americas [Member]
Segment Reporting Information [Line Items]
Revenue	2,324	2,043
Europe [Member]
Segment Reporting Information [Line Items]
Revenue	1,093	906
Asia-Pacific [Member]
Segment Reporting Information [Line Items]
Revenue	$ 166	$ 143

Segment Information - Schedule

Segment Information - Schedule of Long-Lived Assets by Geographic Region (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Long-lived assets	$ 13,806	$ 13,812
Americas [Member]
Segment Reporting Information [Line Items]
Long-lived assets	13,551	13,560
Europe [Member]
Segment Reporting Information [Line Items]
Long-lived assets	172	168
Asia-Pacific [Member]
Segment Reporting Information [Line Items]
Long-lived assets	$ 83	$ 84

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)	May 09, 2018
DSP Black Rock Investment Managers Pvt Ltd [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Percentage of stake in joint venture	40.00%