State Street (STT) 10-K 26 Feb 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	STATE STREET Corp
Entity Central Index Key	93,751
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		367,653,199
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 33,380

Consolidated Statement of Incom

Consolidated Statement of Income - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fee revenue:
Servicing fees	$ 5,365	$ 5,073	$ 5,153
Management fees	1,616	1,292	1,174
Trading services	1,071	1,099	1,146
Securities finance	606	562	496
Processing fees and other	247	90	309
Total fee revenue	8,905	8,116	8,278
Net interest income:
Interest income	2,908	2,512	2,488
Interest expense	604	428	400
Net interest income	2,304	2,084	2,088
Gains (losses) related to investment securities, net:
Gains (losses) from sales of available-for-sale securities, net	(39)	10	(5)
Losses from other-than-temporary impairment	0	(2)	(1)
Losses reclassified (from) to other comprehensive income	0	(1)	0
Gains (losses) related to investment securities, net	(39)	7	(6)
Total revenue	11,170	10,207	10,360
Provision for loan losses	2	10	12
Expenses:
Compensation and employee benefits	4,394	4,353	4,061
Information systems and communications	1,167	1,105	1,022
Transaction processing services	838	800	793
Occupancy	461	440	444
Acquisition and restructuring costs	266	209	25
Professional services	340	379	490
Amortization of other intangible assets	214	207	197
Other	589	584	1,018
Total expenses	8,269	8,077	8,050
Income before income tax expense (benefit)	2,899	2,120	2,298
Income tax expense (benefit)	722	(22)	318
Net income from non-controlling interest	0	1	0
Net income	2,177	2,143	1,980
Net income available to common shareholders	$ 1,993	$ 1,968	$ 1,848
Earnings per common share:
Basic (in USD per share)	$ 5.32	$ 5.03	$ 4.53
Diluted (in USD per share)	$ 5.24	$ 4.97	$ 4.47
Average common shares outstanding (in thousands):
Basic (in shares)	374,793	391,485	407,856
Diluted (in shares)	380,213	396,090	413,638
Cash dividends declared (in USD per share)	$ 1.6	$ 1.44	$ 1.32

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 2,177	$ 2,143	$ 1,980
Other comprehensive income (loss), net of related taxes:
Foreign currency translation, net of related taxes of $21, ($11) and ($101), respectively	900	(372)	(735)
Net unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment and net of related taxes of $272, ($119), and ($195), respectively	367	(181)	(331)
Net unrealized gains (losses) on available-for-sale securities designated in fair value hedges, net of related taxes of $16, $16 and $5, respectively	22	23	12
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes of $3, $5 and $8, respectively	3	7	13
Net unrealized gains (losses) on cash flow hedges, net of related taxes of ($181), ($42) and $24, respectively	(285)	(64)	17
Net unrealized gains (losses) on retirement plans, net of related taxes of $8, $1 and $51, respectively	24	(11)	89
Other comprehensive income (loss)	1,031	(598)	(935)
Total comprehensive income	$ 3,208	$ 1,545	$ 1,045

Consolidated Statement of Comp4

Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Foreign currency translation, Taxes	$ 21	$ (11)	$ (101)
Change in net unrealized losses on available-for-sale securities, Taxes	272	(119)	(195)
Change in net unrealized losses on available-for-sale securities designated in fair value hedges, Taxes	16	16	5
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, Taxes	3	5	8
Change in net unrealized losses on cash flow hedges, Taxes	(181)	(42)	24
Change in unrealized losses on retirement plans, Taxes	$ 8	$ 1	$ 51

Consolidated Statement of Condi

Consolidated Statement of Condition - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets:
Cash and due from banks	$ 2,107	$ 1,314
Interest-bearing deposits with banks	67,227	70,935
Securities purchased under resale agreements	3,241	1,956
Trading account assets	1,093	1,024
Investment securities available-for-sale	57,121	61,998
Investment securities held-to-maturity (fair value of $40,255 and $34,994)	40,458	35,169
Loans and leases (less allowance for losses of $54 and $53)	23,240	19,704
Premises and equipment (net of accumulated depreciation of $3,881 and $3,333)	2,186	2,062
Accrued interest and fees receivable	3,099	2,644
Goodwill	6,022	5,814
Other intangible assets	1,613	1,750
Other assets	31,018	38,328
Total assets	238,425	242,698
Deposits:
Non-interest-bearing	47,175	59,397
Interest-bearing—U.S.	50,139	30,911
Interest-bearing—non-U.S.	87,582	96,855
Total deposits	184,896	187,163
Securities sold under repurchase agreements	2,842	4,400
Other short-term borrowings	1,144	1,585
Accrued expenses and other liabilities	15,606	16,901
Long-term debt	11,620	11,430
Total liabilities	216,108	221,479
Commitments, guarantees and contingencies (Notes 12 and 13)
Shareholders’ equity:
Common stock, $1 par: 750,000,000 shares authorized; 503,879,642 and 503,879,642 shares issued	504	504
Surplus	9,799	9,782
Retained earnings	18,856	17,459
Accumulated other comprehensive income (loss)	(1,009)	(2,040)
Treasury stock, at cost (136,229,784 and 121,940,502 shares)	(9,029)	(7,682)
Total shareholders’ equity	22,317	21,219
Total liabilities and shareholders' equity	238,425	242,698
Series C Preferred Stock
Shareholders’ equity:
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding, Series D, 7,500 shares issued and outstanding, Series E, 7,500 shares issued and outstanding, Series F, 7,500 shares issued and outstanding, and Series G, 5,000 shares issued and outstanding	491	491
Series D Preferred Stock
Shareholders’ equity:
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding, Series D, 7,500 shares issued and outstanding, Series E, 7,500 shares issued and outstanding, Series F, 7,500 shares issued and outstanding, and Series G, 5,000 shares issued and outstanding	742	742
Series E Preferred Stock
Shareholders’ equity:
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding, Series D, 7,500 shares issued and outstanding, Series E, 7,500 shares issued and outstanding, Series F, 7,500 shares issued and outstanding, and Series G, 5,000 shares issued and outstanding	728	728
Series F Preferred Stock
Shareholders’ equity:
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding, Series D, 7,500 shares issued and outstanding, Series E, 7,500 shares issued and outstanding, Series F, 7,500 shares issued and outstanding, and Series G, 5,000 shares issued and outstanding	742	742
Series G Preferred Stock
Shareholders’ equity:
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding, Series D, 7,500 shares issued and outstanding, Series E, 7,500 shares issued and outstanding, Series F, 7,500 shares issued and outstanding, and Series G, 5,000 shares issued and outstanding	$ 493	$ 493

Consolidated Statement of Cond6

Consolidated Statement of Condition (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Investment securities held-to-maturity, fair value	$ 40,255	$ 34,994
Loans and leases, allowance for losses	54	53
Premises and equipment, accumulated depreciation	$ 3,881	$ 3,333
Stockholders' Equity:
Preferred stock, no par value (in USD per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	3,500,000	3,500,000
Common stock, par value (in USD per share)	$ 1	$ 1
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	503,879,642	503,879,642
Treasury stock, shares	136,229,784	121,940,502
Series C Preferred Stock
Stockholders' Equity:
Preferred stock, shares issued	5,000	5,000
Preferred stock, shares outstanding	5,000	5,000
Series D Preferred Stock
Stockholders' Equity:
Preferred stock, shares issued	7,500	7,500
Preferred stock, shares outstanding	7,500	7,500
Series E Preferred Stock
Stockholders' Equity:
Preferred stock, shares issued	7,500	7,500
Preferred stock, shares outstanding	7,500	7,500
Series F Preferred Stock
Stockholders' Equity:
Preferred stock, shares issued	7,500	7,500
Preferred stock, shares outstanding	7,500	7,500
Series G Preferred Stock
Stockholders' Equity:
Preferred stock, shares issued	5,000	5,000
Preferred stock, shares outstanding	5,000	5,000

Consolidated Statement of Chang

Consolidated Statement of Changes In Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	PREFERRED STOCK	COMMON STOCK	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	TREASURY STOCK
Beginning balance at Dec. 31, 2014	$ 21,328	$ 1,961	$ 504	$ 9,791	$ 14,737	$ (507)	$ (5,158)
Beginning balance (shares) at Dec. 31, 2014			503,880				88,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,980
Other comprehensive loss	(935)
Preferred stock issued	742	742
Cash dividends declared:
Common stock dividends	(536)				(536)
Preferred stock cash dividend	(130)				(130)
Common stock acquired	(1,520)						$ (1,520)
Common stock acquired (shares)							20,521
Common stock awards exercised	180			(41)			$ 221
Common stock awards and options exercised (shares)							(4,976)
Other	(6)			(4)	(2)
Other (shares)							(2)
Ending balance at Dec. 31, 2015	21,103	2,703	$ 504	9,746	16,049	(1,442)	$ (6,457)
Ending balance (shares) at Dec. 31, 2015			503,880				104,228
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,143				2,143
Other comprehensive loss	(598)					(598)
Preferred stock issued	493	493
Cash dividends declared:
Common stock dividends	(559)				(559)
Preferred stock cash dividend	(173)				(173)
Common stock acquired	(1,365)						$ (1,365)
Common stock acquired (shares)							21,098
Common stock awards exercised	175			36			$ 139
Common stock awards and options exercised (shares)							(3,369)
Other	0				(1)		$ 1
Other (shares)							(16)
Ending balance at Dec. 31, 2016	21,219	3,196	$ 504	9,782	17,459	(2,040)	$ (7,682)
Ending balance (shares) at Dec. 31, 2016			503,880				121,941
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,177				2,177
Other comprehensive loss	1,031					1,031
Preferred stock issued	0
Cash dividends declared:
Common stock dividends	(596)				(596)
Preferred stock cash dividend	(182)				(182)
Common stock acquired	(1,450)						$ (1,450)
Common stock acquired (shares)							16,788
Common stock awards exercised	120			16			$ 104
Common stock awards and options exercised (shares)							(2,503)
Other	(2)			1	(2)		$ (1)
Other (shares)							(4)
Ending balance at Dec. 31, 2017	$ 22,317	$ 3,196	$ 504	$ 9,799	$ 18,856	$ (1,009)	$ (9,029)
Ending balance (shares) at Dec. 31, 2017			503,880				136,230

Consolidated Statement of Chan8

Consolidated Statement of Changes In Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Cash dividends declared (in USD per share)	$ 1.44	$ 1.32
Common stock awards and options exercised, related taxes	$ 13	$ 70

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities:
Net income	$ 2,177	$ 2,143	$ 1,980
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Deferred income tax (benefit)	95	(358)	(168)
Amortization of other intangible assets	214	207	197
Other non-cash adjustments for depreciation, amortization and accretion, net	871	722	604
Losses (gains) related to investment securities, net	39	(7)	6
Change in trading account assets, net	(69)	(175)	75
Change in accrued interest and fees receivable, net	(455)	(298)	(104)
Change in collateral deposits, net	1,819	(18)	(6,662)
Change in unrealized losses on foreign exchange derivatives, net	3,267	(1,057)	982
Change in other assets, net	(1,341)	1,772	1,156
Change in accrued expenses and other liabilities, net	9	(1,147)	(48)
Other, net	307	506	579
Net cash provided by (used in) operating activities	6,933	2,290	(1,403)
Investing Activities:
Net decrease in interest-bearing deposits with banks	3,708	4,403	18,185
Net (increase) decrease in securities purchased under resale agreements	(1,285)	1,448	(1,014)
Proceeds from sales of available-for-sale securities	12,439	1,401	12,309
Proceeds from maturities of available-for-sale securities	28,878	30,070	28,025
Purchases of available-for-sale securities	(34,841)	(30,162)	(25,397)
Proceeds from maturities of held-to-maturity securities	4,028	7,942	3,842
Purchases of held-to-maturity securities	(8,772)	(8,425)	(9,398)
Net (increase) in loans and leases	(3,511)	(924)	(561)
Business acquisitions	0	(437)	0
Purchases of equity investments and other long-term assets	(233)	(643)	(366)
Purchases of premises and equipment, net	(637)	(613)	(703)
Proceeds from sale of joint venture investment	172	0	0
Other, net	102	170	73
Net cash provided by investing activities	48	4,230	24,995
Financing Activities:
Net (decrease) increase in time deposits	(15,306)	8,488	(9,878)
Net increase (decrease) in all other deposits	13,040	(12,952)	(7,535)
Net (decrease) in other short-term borrowings	(1,999)	(268)	(7,074)
Proceeds from issuance of long-term debt, net of issuance costs	747	1,492	2,983
Payments for long-term debt and obligations under capital leases	(493)	(1,441)	(1,155)
Proceeds from issuance of preferred stock, net	0	493	742
Proceeds from exercises of common stock options	0	0	4
Purchases of common stock	(1,292)	(1,365)	(1,520)
Excess tax benefit related to stock-based compensation	0	13	70
Repurchases of common stock for employee tax withholding	(126)	(122)	(222)
Payments for cash dividends	(768)	(723)	(655)
Other, net	9	(28)	0
Net cash (used in) financing activities	(6,188)	(6,413)	(24,240)
Net increase (decrease)	793	107	(648)
Cash and due from banks at beginning of period	1,314	1,207	1,855
Cash and due from banks at end of period	$ 2,107	$ 1,314	$ 1,207

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accounting and financial reporting policies of State Street Corporation conform to U.S. GAAP. State Street Corporation, the Parent Company, is a financial holding company headquartered in Boston, Massachusetts. Unless otherwise indicated or unless the context requires otherwise, all references in these notes to consolidated financial statements to “State Street,” “we,” “us,” “our” or similar references mean State Street Corporation and its subsidiaries on a consolidated basis, including our principal banking subsidiary, State Street Bank. We have two lines of business: Investment Servicing provides products and services including: custody; product and participant level accounting; daily pricing and administration; master trust and master custody; depotbank services (a fund oversight role created by regulation); record-keeping; cash management; foreign exchange, brokerage and other trading services; securities finance; our enhanced custody product, which integrates principal securities lending and custody; deposit and short-term investment facilities; loans and lease financing; investment manager and alternative investment manager operations outsourcing; performance, risk and compliance analytics; and financial data management to support institutional investors. Investment Management , through SSGA, provides a broad array of investment management, investment research and investment advisory services to corporations, public funds and other sophisticated investors. SSGA offers passive and active asset management strategies across equity, fixed-income, alternative, multi-asset solutions (including OCIO) and cash asset classes. Products are distributed directly and through intermediaries using a variety of investment vehicles, including ETFs, such as the SPDR ® ETF brand. Consolidation Our consolidated financial statements include the accounts of the Parent Company and its majority- and wholly-owned and otherwise controlled subsidiaries, including State Street Bank. All material inter-company transactions and balances have been eliminated. Certain previously reported amounts have been reclassified to conform to current-year presentation. We consolidate subsidiaries in which we exercise control. Investments in unconsolidated subsidiaries, recorded in other assets, generally are accounted for under the equity method of accounting if we have the ability to exercise significant influence over the operations of the investee. For investments accounted for under the equity method, our share of income or loss is recorded in processing fees and other revenue in our consolidated statement of income. Investments not meeting the criteria for equity-method treatment are accounted for under the cost method of accounting. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions in the application of certain of our significant accounting policies that may materially affect the reported amounts of assets, liabilities, equity, revenue, and expenses. As a result of unanticipated events or circumstances, actual results could differ from those estimates. Foreign Currency Translation The assets and liabilities of our operations with functional currencies other than the U.S. dollar are translated at month-end exchange rates, and revenue and expenses are translated at rates that approximate average monthly exchange rates. Gains or losses from the translation of the net assets of subsidiaries with functional currencies other than the U.S. dollar, net of related taxes, are recorded in AOCI, a component of shareholders’ equity. Cash and Cash Equivalents For purposes of the consolidated statement of cash flows, cash and cash equivalents are defined as cash and due from banks. Interest-Bearing Deposits with Banks Interest-bearing deposits with banks generally consist of highly liquid, short-term investments maintained at the Federal Reserve Bank and other non-U.S. central banks with original maturities at the time of purchase of one month or less. Securities Purchased Under Resale Agreements and Securities Sold Under Repurchase Agreements Securities purchased under resale agreements and sold under repurchase agreements are treated as collateralized financing transactions, and are recorded in our consolidated statement of condition at the amounts at which the securities will be subsequently resold or repurchased, plus accrued interest. Our policy is to take possession or control of securities underlying resale agreements either directly or through agent banks, allowing borrowers the right of collateral substitution and/or short-notice termination. We revalue these securities daily to determine if additional collateral is necessary from the borrower to protect us against credit exposure. We can use these securities as collateral for repurchase agreements. For securities sold under repurchase agreements collateralized by our investment securities portfolio, the dollar value of the securities remains in investment securities in our consolidated statement of condition. Where a master netting agreement exists or both parties are members of a common clearing organization, resale and repurchase agreements with the same counterparty or clearing house and maturity date are recorded on a net basis. Fee and Net Interest Income Fees from investment servicing, investment management, securities finance, trading services and certain types of processing fees and other revenue are recorded in our consolidated statement of income based on estimates or specific contractual terms, including mutually agreed changes to terms, as transactions occur or services are rendered, provided that persuasive evidence exists, the price to the client is fixed or determinable and collectability is reasonably assured. Amounts accrued at period-end are recorded in accrued interest and fees receivable in our consolidated statement of condition. Performance fees generated by our investment management activities are recorded when the performance period is complete, based on predetermined benchmarks associated with the applicable fund’s performance. Interest income on interest-earning assets and interest expense on interest-bearing liabilities are recorded in our consolidated statement of income as components of NII, and are generally based on the effective yield of the related financial asset or liability. Other Significant Policies The following table identifies our other significant accounting policies and the note and page where a detailed description of each policy can be found. Fair Value Note 2 Page Investment Securities Note 3 Page Loans and Leases Note 4 Page Goodwill and Other Intangible Assets Note 5 Page Derivative Financial Instruments Note 10 Page Offsetting Arrangements Note 11 Page Contingencies Note 13 Page Variable Interest Entities Note 14 Page Regulatory Capital Note 16 Page Equity-Based Compensation Note 18 Page Income Taxes Note 22 Page Earnings Per Common Share Note 23 Page Acquisitions and Dispositions In the first quarter of 2017, we completed the sale of our joint venture interest in IFDS U.K. for approximately $175 million in cash and the exchange of our joint venture interest in BFDS stock for $158 million in State Street's common stock. We recognized a pre-tax gain of $30 million , in the aggregate, in the year ended December 31, 2017 on these dispositions. In the third quarter of 2017, we recognized a pre-tax gain of $26 million on the sale of an alternative trading platform. On July 1, 2016, we completed our acquisition of GE Asset Management (GEAM) from General Electric Company, with a total purchase price of approximately $485 million . We accounted for this acquisition as a business combination and, in accordance with ASC Topic 805, Business Combinations , we have recorded assets acquired and liabilities assumed at their respective fair values as of the acquisition date. Our consolidated financial statements include the operating results for the acquired business from the date of acquisition, July 1, 2016. Recent Accounting Developments Relevant standards that were recently issued but not yet adopted Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2014-09, Revenue from Contracts with Customers (Topic 606) The standard, and its related amendments, will replace existing revenue recognition standards and expand the disclosure requirements for revenue arrangements with customers. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). January 1, 2018 The timing and amount of our material revenue streams, including servicing fees, management fees, trading services, and securities finance, remain substantially unchanged as these revenues will continue to be recognized over time. Specifically, under the new standard we will recognize revenue related to these activities ratably over the term of the related agreements with customers as the customer simultaneously benefits from the services as they are performed. The standard does not apply to revenue associated with financial instruments, including loans and securities, or revenue recognized under other U.S. GAAP standards. Therefore NII, securities gains/ losses and revenue related to derivative instruments are not impacted by the standard. The new standard modified the principal and agent guidance requiring certain costs previously presented on a net basis to be presented on a gross basis, which we expect will increase 2018 revenue and expenses by an estimated $225 million, the majority reflected in Investment Management. We have adopted the new standard as of January 1, 2018, using the modified retrospective method of adoption. No material adjustment to retained earnings was required. ASU 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard makes limited amendments to the guidance on the classification and measurement of financial instruments. Under the new standard, all equity securities will be measured at fair value through earnings with certain exceptions, including investments accounted for under the equity method of accounting. In addition, the FASB clarified the guidance related to valuation allowance assessments when recognizing deferred tax assets on unrealized losses on available-for-sale debt securities. This standard must be applied on a retrospective basis. January 1, 2018 Upon adoption of the standard on January 1, 2018, we reclassified approximately $443 million of equity securities classified as available for sale to equity securities held at fair value through profit and loss. The cumulative-effect transition adjustment recognized in retained earnings on January 1, 2018 was immaterial to the financial statements. ASU 2016-02, Leases (Topic 842) The standard represents a wholesale change to lease accounting and requires all leases, other than short-term leases, to be reported on balance sheet through recognition of a right-of-use asset and a corresponding liability for future lease obligations. The standard also requires extensive disclosures for assets, expenses, and cash flows associated with leases, as well as a maturity analysis of lease liabilities. January 1, 2019 We are currently assessing the impact of the standard on our consolidated financial statements, but we anticipate an increase in assets and liabilities due to the recognition of the required right-of-use asset and corresponding liability for all lease obligations that are currently classified as operating leases, primarily real estate leases for office space, as well as additional disclosure on all of our lease obligations. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments The standard requires immediate recognition of expected credit losses for financial assets carried at amortized cost, including trade and other receivables, loans and commitments, held-to-maturity debt securities, and other financial assets, held at the reporting date to be measured based on historical experience, current conditions, and reasonable supportable forecasts. Credit losses on available for sale securities will be recorded as an allowance versus a write-down of the amortized cost basis of the security and will allow for a reversal of impairment loss when the credit of the issuer improves. January 1, 2020 We are currently assessing the impact of the standard on our consolidated financial statements, and a significant implementation project is in place to ensure that expected credit losses are calculated in accordance with the standard. We have established a steering committee to provide cross-functional governance over the project plan and key decisions, and are currently developing key accounting policies, assessing existing credit loss models against the new guidance and processes and identifying a complete set of data requirements and sources. We have commenced the development of new or modified credit loss models and based on our analysis to date, we expect the timing of the allowance for credit losses to accelerate under the new standard. We are continuing to assess the extent of the impact on the allowance for credit losses. Relevant standards that were recently issued but not yet adopted (continued) Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) The standard amends the statement of cash flow guidance to address specific cash flow issues with the objective of reducing the existing diversity in practice. January 1, 2018 Based on our current presentation there is no significant change to our presentation of the statement of cash flows. ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business The standard incorporates gating criteria to determine when an integrated set of assets and activities is not a business. When substantially all the fair value of gross assets acquired (or group of similar identifiable assets) is concentrated in a single identifiable asset, it would not represent a business. January 1, 2018, early adoption permitted We have adopted this standard as of January 1, 2018 and will apply it prospectively to transactions occurring after adoption date, as applicable. ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment The standard simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. The ASU requires an entity to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying value exceeds the fair value of the reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss. January 1, 2020, early adoption permitted We are evaluating the impacts of early adoption, and will apply this standard prospectively upon adoption. ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities The standard shortens the amortization period for certain purchased callable debt securities to the earliest call date. January 1, 2019, early adoption permitted We are currently evaluating the impact of the new standard and the early adoption provisions. ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities The standard amends the hedge accounting model to better portray the economics of risk management activities in the financial statements and enhances the presentation of hedge results. The amendments also make targeted changes to simplify the application of hedge accounting in certain situations. January 1, 2019, early adoption permitted We are currently evaluating the impact of the new standard and the early adoption provisions. Relevant standards that were adopted during the year ended December 31, 2017 We adopted ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, effective January 1, 2017. Starting in the quarter ended March 31, 2017, we reclassified excess tax benefits related to stock-based compensation from financing activities to other operating activities on the consolidated statement of cash flows. We continued to present repurchases of common stock for employee tax withholding in financing activities in the consolidated statements of cash flows for all periods presented. As required by the transition provisions of the standard, excess tax benefits previously recognized in surplus prior to January 1, 2017 remain in surplus, and excess tax benefits recognized after January 1, 2017 are included in income tax expense. In connection with this change, we recognized a tax benefit of $24.8 million in the year ended December 31, 2017. We elected to make no changes to our current policy of estimating forfeitures or our tax withholding rates. Summary of Significant Accounting Policies Basis of Presentation The accounting and financial reporting policies of State Street Corporation conform to U.S. GAAP. State Street Corporation, the Parent Company, is a financial holding company headquartered in Boston, Massachusetts. Unless otherwise indicated or unless the context requires otherwise, all references in these notes to consolidated financial statements to “State Street,” “we,” “us,” “our” or similar references mean State Street Corporation and its subsidiaries on a consolidated basis, including our principal banking subsidiary, State Street Bank. We have two lines of business: Investment Servicing provides products and services including: custody; product and participant level accounting; daily pricing and administration; master trust and master custody; depotbank services (a fund oversight role created by regulation); record-keeping; cash management; foreign exchange, brokerage and other trading services; securities finance; our enhanced custody product, which integrates principal securities lending and custody; deposit and short-term investment facilities; loans and lease financing; investment manager and alternative investment manager operations outsourcing; performance, risk and compliance analytics; and financial data management to support institutional investors. Investment Management , through SSGA, provides a broad array of investment management, investment research and investment advisory services to corporations, public funds and other sophisticated investors. SSGA offers passive and active asset management strategies across equity, fixed-income, alternative, multi-asset solutions (including OCIO) and cash asset classes. Products are distributed directly and through intermediaries using a variety of investment vehicles, including ETFs, such as the SPDR ® ETF brand. Consolidation Our consolidated financial statements include the accounts of the Parent Company and its majority- and wholly-owned and otherwise controlled subsidiaries, including State Street Bank. All material inter-company transactions and balances have been eliminated. Certain previously reported amounts have been reclassified to conform to current-year presentation. We consolidate subsidiaries in which we exercise control. Investments in unconsolidated subsidiaries, recorded in other assets, generally are accounted for under the equity method of accounting if we have the ability to exercise significant influence over the operations of the investee. For investments accounted for under the equity method, our share of income or loss is recorded in processing fees and other revenue in our consolidated statement of income. Investments not meeting the criteria for equity-method treatment are accounted for under the cost method of accounting. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions in the application of certain of our significant accounting policies that may materially affect the reported amounts of assets, liabilities, equity, revenue, and expenses. As a result of unanticipated events or circumstances, actual results could differ from those estimates. Foreign Currency Translation The assets and liabilities of our operations with functional currencies other than the U.S. dollar are translated at month-end exchange rates, and revenue and expenses are translated at rates that approximate average monthly exchange rates. Gains or losses from the translation of the net assets of subsidiaries with functional currencies other than the U.S. dollar, net of related taxes, are recorded in AOCI, a component of shareholders’ equity. Cash and Cash Equivalents For purposes of the consolidated statement of cash flows, cash and cash equivalents are defined as cash and due from banks. Interest-Bearing Deposits with Banks Interest-bearing deposits with banks generally consist of highly liquid, short-term investments maintained at the Federal Reserve Bank and other non-U.S. central banks with original maturities at the time of purchase of one month or less. Securities Purchased Under Resale Agreements and Securities Sold Under Repurchase Agreements Securities purchased under resale agreements and sold under repurchase agreements are treated as collateralized financing transactions, and are recorded in our consolidated statement of condition at the amounts at which the securities will be subsequently resold or repurchased, plus accrued interest. Our policy is to take possession or control of securities underlying resale agreements either directly or through agent banks, allowing borrowers the right of collateral substitution and/or short-notice termination. We revalue these securities daily to determine if additional collateral is necessary from the borrower to protect us against credit exposure. We can use these securities as collateral for repurchase agreements. For securities sold under repurchase agreements collateralized by our investment securities portfolio, the dollar value of the securities remains in investment securities in our consolidated statement of condition. Where a master netting agreement exists or both parties are members of a common clearing organization, resale and repurchase agreements with the same counterparty or clearing house and maturity date are recorded on a net basis. Fee and Net Interest Income Fees from investment servicing, investment management, securities finance, trading services and certain types of processing fees and other revenue are recorded in our consolidated statement of income based on estimates or specific contractual terms, including mutually agreed changes to terms, as transactions occur or services are rendered, provided that persuasive evidence exists, the price to the client is fixed or determinable and collectability is reasonably assured. Amounts accrued at period-end are recorded in accrued interest and fees receivable in our consolidated statement of condition. Performance fees generated by our investment management activities are recorded when the performance period is complete, based on predetermined benchmarks associated with the applicable fund’s performance. Interest income on interest-earning assets and interest expense on interest-bearing liabilities are recorded in our consolidated statement of income as components of NII, and are generally based on the effective yield of the related financial asset or liability. Other Significant Policies The following table identifies our other significant accounting policies and the note and page where a detailed description of each policy can be found. Fair Value Note 2 Page Investment Securities Note 3 Page Loans and Leases Note 4 Page Goodwill and Other Intangible Assets Note 5 Page Derivative Financial Instruments Note 10 Page Offsetting Arrangements Note 11 Page Contingencies Note 13 Page Variable Interest Entities Note 14 Page Regulatory Capital Note 16 Page Equity-Based Compensation Note 18 Page Income Taxes Note 22 Page Earnings Per Common Share Note 23 Page Acquisitions and Dispositions In the first quarter of 2017, we completed the sale of our joint venture interest in IFDS U.K. for approximately $175 million in cash and the exchange of our joint venture interest in BFDS stock for $158 million in State Street's common stock. We recognized a pre-tax gain of $30 million , in the aggregate, in the year ended December 31, 2017 on these dispositions. In the third quarter of 2017, we recognized a pre-tax gain of $26 million on the sale of an alternative trading platform. On July 1, 2016, we completed our acquisition of GE Asset Management (GEAM) from General Electric Company, with a total purchase price of approximately $485 million . We accounted for this acquisition as a business combination and, in accordance with ASC Topic 805, Business Combinations , we have recorded assets acquired and liabilities assumed at their respective fair values as of the acquisition date. Our consolidated financial statements include the operating results for the acquired business from the date of acquisition, July 1, 2016. Recent Accounting Developments Relevant standards that were recently issued but not yet adopted Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2014-09, Revenue from Contracts with Customers (Topic 606) The standard, and its related amendments, will replace existing revenue recognition standards and expand the disclosure requirements for revenue arrangements with customers. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). January 1, 2018 The timing and amount of our material revenue streams, including servicing fees, management fees, trading services, and securities finance, remain substantially unchanged as these revenues will continue to be recognized over time. Specifically, under the new standard we will recognize revenue related to these activities ratably over the term of the related agreements with customers as the customer simultaneously benefits from the services as they are performed. The standard does not apply to revenue associated with financial instruments, including loans and securities, or revenue recognized under other U.S. GAAP standards. Therefore NII, securities gains/ losses and revenue related to derivative instruments are not impacted by the standard. The new standard modified the principal and agent guidance requiring certain costs previously presented on a net basis to be presented on a gross basis, which we expect will increase 2018 revenue and expenses by an estimated $225 million, the majority reflected in Investment Management. We have adopted the new standard as of January 1, 2018, using the modified retrospective method of adoption. No material adjustment to retained earnings was required. ASU 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard makes limited amendments to the guidance on the classification and measurement of financial instruments. Under the new standard, all equity securities will be measured at fair value through earnings with certain exceptions, including investments accounted for under the equity method of accounting. In addition, the FASB clarified the guidance related to valuation allowance assessments when recognizing deferred tax assets on unrealized losses on available-for-sale debt securities. This standard must be applied on a retrospective basis. January 1, 2018 Upon adoption of the standard on January 1, 2018, we reclassified approximately $443 million of equity securities classified as available for sale to equity securities held at fair value through profit and loss. The cumulative-effect transition adjustment recognized in retained earnings on January 1, 2018 was immaterial to the financial statements. ASU 2016-02, Leases (Topic 842) The standard represents a wholesale change to lease accounting and requires all leases, other than short-term leases, to be reported on balance sheet through recognition of a right-of-use asset and a corresponding liability for future lease obligations. The standard also requires extensive disclosures for assets, expenses, and cash flows associated with leases, as well as a maturity analysis of lease liabilities. January 1, 2019 We are currently assessing the impact of the standard on our consolidated financial statements, but we anticipate an increase in assets and liabilities due to the recognition of the required right-of-use asset and corresponding liability for all lease obligations that are currently classified as operating leases, primarily real estate leases for office space, as well as additional disclosure on all of our lease obligations. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments The standard requires immediate recognition of expected credit losses for financial assets carried at amortized cost, including trade and other receivables, loans and commitments, held-to-maturity debt securities, and other financial assets, held at the reporting date to be measured based on historical experience, current conditions, and reasonable supportable forecasts. Credit losses on available for sale securities will be recorded as an allowance versus a write-down of the amortized cost basis of the security and will allow for a reversal of impairment loss when the credit of the issuer improves. January 1, 2020 We are currently assessing the impact of the standard on our consolidated financial statements, and a significant implementation project is in place to ensure that expected credit losses are calculated in accordance with the standard. We have established a steering committee to provide cross-functional governance over the project plan and key decisions, and are currently developing key accounting policies, assessing existing credit loss models against the new guidance and processes and identifying a complete set of data requirements and sources. We have commenced the development of new or modified credit loss models and based on our analysis to date, we expect the timing of the allowance for credit losses to accelerate under the new standard. We are continuing to assess the extent of the impact on the allowance for credit losses. Relevant standards that were recently issued but not yet adopted (continued) Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) The standard amends the statement of cash flow guidance to address specific cash flow issues with the objective of reducing the existing diversity in practice. January 1, 2018 Based on our current presentation there is no significant change to our presentation of the statement of cash flows. ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business The standard incorporates gating criteria to determine when an integrated set of assets and activities is not a business. When substantially all the fair value of gross assets acquired (or group

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Fair Value Measurements We carry trading account assets and liabilities, AFS investment securities and various types of derivative financial instruments at fair value in our consolidated statement of condition on a recurring basis. Changes in the fair values of these financial assets and liabilities are recorded either as components of our consolidated statement of income or as components of AOCI within shareholders' equity in our consolidated statement of condition. We measure fair value for the above-described financial assets and liabilities in conformity with U.S. GAAP that governs the measurement of the fair value of financial instruments. Management believes that its valuation techniques and underlying assumptions used to measure fair value conform to the provisions of U.S. GAAP. We categorize the financial assets and liabilities that we carry at fair value based on a prescribed three-level valuation hierarchy. The hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (level 1) and the lowest priority to valuation methods using significant unobservable inputs (level 3). If the inputs used to measure a financial asset or liability cross different levels of the hierarchy, categorization is based on the lowest-level input that is significant to the fair-value measurement. Management's assessment of the significance of a particular input to the overall fair-value measurement of a financial asset or liability requires judgment, and considers factors specific to that asset or liability. The three levels of the valuation hierarchy are described below. Level 1. Financial assets and liabilities with values based on unadjusted quoted prices for identical assets or liabilities in an active market. Our level 1 financial assets and liabilities primarily include positions in U.S. government securities and highly liquid U.S. and non-U.S. government fixed-income securities carried in trading account assets. We may carry U.S. government securities in our AFS portfolio in connection with our asset-and-liability management activities. Our level 1 financial assets also include active exchange-traded equity securities. Level 2. Financial assets and liabilities with values based on quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. Level 2 inputs include the following: • Quoted prices for similar assets or liabilities in active markets; • Quoted prices for identical or similar assets or liabilities in non-active markets; • Pricing models whose inputs are observable for substantially the full term of the asset or liability; and • Pricing models whose inputs are derived principally from, or corroborated by, observable market information through correlation or other means for substantially the full term of the asset or liability. Our level 2 financial assets and liabilities primarily include non-U.S. debt securities carried in trading account assets and various types of fixed-income investment securities available-for-sale, as well as various types of foreign exchange and interest-rate derivative instruments. Fair value for our investment securities available-for-sale categorized in level 2 is measured primarily using information obtained from independent third parties. This third-party information is subject to review by management as part of a validation process, which includes obtaining an understanding of the underlying assumptions and the level of market participant information used to support those assumptions. In addition, management compares significant assumptions used by third parties to available market information. Such information may include known trades or, to the extent that trading activity is limited, comparisons to market research information pertaining to credit expectations, execution prices and the timing of cash flows and, where information is available, back-testing. Derivative instruments categorized in level 2 predominantly represent foreign exchange contracts used in our trading activities, for which fair value is measured using discounted cash-flow techniques, with inputs consisting of observable spot and forward points, as well as observable interest-rate curves. With respect to derivative instruments, we evaluate the impact on valuation of the credit risk of our counterparties and our own credit risk. We consider factors such as the likelihood of default by us and our counterparties, our current and potential future net exposures and remaining maturities in determining the fair value. Valuation adjustments associated with derivative instruments were not material to those instruments for the years ended December 31, 2017 and 2016 . Level 3. Financial assets and liabilities with values based on prices or valuation techniques that require inputs that are both unobservable in the market and significant to the overall measurement of fair value. These inputs reflect management's judgment about the assumptions that a market participant would use in pricing the financial asset or liability, and are based on the best available information, some of which is internally developed. The following provides a more detailed discussion of our financial assets and liabilities that we may categorize in level 3 and the related valuation methodology. • The fair value of our investment securities categorized in level 3 is measured using information obtained from third-party sources, typically non-binding broker or dealer quotes, or through the use of internally-developed pricing models. Management has evaluated its methodologies used to measure fair value, but has considered the level of observable market information to be insufficient to categorize the securities in level 2. • The fair value of certain foreign exchange contracts, primarily options, is measured using an option-pricing model. Because of a limited number of observable transactions, certain model inputs are not observable, such as implied volatility surface, but are derived from observable market information. Our level 3 financial assets and liabilities are similar in structure and profile to our level 1 and level 2 financial instruments, but they trade in less liquid markets, and the measurement of their fair value is inherently more difficult. The following tables present information with respect to our financial assets and liabilities carried at fair value in our consolidated statement of condition on a recurring basis as of the dates indicated. During 2017 , approximately $9 million of assets were transferred between levels 1 and 2. No transfers of financial assets or liabilities between levels 1 and 2 occurred during 2016 . Fair Value Measurements on a Recurring Basis as of December 31, 2017 (In millions) Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) Impact of Netting (1) Total Net Carrying Value in Consolidated Statement of Condition Assets: Trading account assets: U.S. government securities $ 39 $ — $ — $ 39 Non-U.S. government securities 389 93 — 482 Other 44 528 — 572 Total trading account assets 472 621 — 1,093 AFS investment securities: U.S. Treasury and federal agencies: Direct obligations 11 212 — 223 Mortgage-backed securities — 10,872 — 10,872 Total U.S. Treasury and federal agencies 11 11,084 — 11,095 Asset-backed securities: Student loans — 3,358 — 3,358 Credit cards — 1,542 — 1,542 Other (2) — 89 1,358 1,447 Total asset-backed securities — 4,989 1,358 6,347 Non-U.S. debt securities: Mortgage-backed securities — 6,576 119 6,695 Asset-backed securities — 2,545 402 2,947 Government securities — 10,721 — 10,721 Other (3) — 5,904 204 6,108 Total non-U.S. debt securities — 25,746 725 26,471 State and political subdivisions — 9,108 43 9,151 Collateralized mortgage obligations — 1,054 — 1,054 Other U.S. debt securities — 2,560 — 2,560 U.S. equity securities — 46 — 46 U.S. money-market mutual funds — 397 — 397 Total AFS investment securities 11 54,984 2,126 57,121 Other assets: Derivative instruments: Foreign exchange contracts — 11,596 1 $ (7,593 ) 4,004 Interest-rate contracts 8 — — — 8 Other derivative contracts 1 — — — 1 Total derivative instruments 9 11,596 1 (7,593 ) 4,013 Total assets carried at fair value $ 492 $ 67,201 $ 2,127 $ (7,593 ) $ 62,227 Liabilities: Accrued expenses and other liabilities: Trading account liabilities: Other $ 39 $ — $ — $ — $ 39 Derivative instruments: Foreign exchange contracts — 11,467 1 (5,970 ) 5,498 Interest-rate contracts — 100 — — 100 Other derivative contracts 1 283 — — 284 Total derivative instruments 1 11,850 1 (5,970 ) 5,882 Total liabilities carried at fair value $ 40 $ 11,850 $ 1 $ (5,970 ) $ 5,921 (1) Represents counterparty netting against level 2 financial assets and liabilities where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $2,045 million and $422 million , respectively, for cash collateral received from and provided to derivative counterparties. (2) As of December 31, 2017 , the fair value of other ABS was primarily composed of $1,447 million of CLOs. (3) As of December 31, 2017 , the fair value of other non-U.S. debt securities was primarily composed of $3,537 million of covered bonds and $1,885 million of corporate bonds. Fair Value Measurements on a Recurring Basis as of December 31, 2016 (In millions) Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) Impact of Netting (1) Total Net Carrying Value in Consolidated Statement of Condition Assets: Trading account assets: U.S. government securities $ 30 $ — $ — $ 30 Non-U.S. government securities 495 174 — 669 Other — 325 — 325 Total trading account assets 525 499 — 1,024 AFS investment securities: U.S. Treasury and federal agencies: Direct obligations 3,824 439 — 4,263 Mortgage-backed securities — 13,257 — 13,257 Total U.S. Treasury and federal agencies 3,824 13,696 — 17,520 Asset-backed securities: Student loans — 5,499 97 5,596 Credit cards — 1,351 — 1,351 Sub-prime — 272 — 272 Other (2) — — 905 905 Total asset-backed securities — 7,122 1,002 8,124 Non-U.S. debt securities: Mortgage-backed securities — 6,535 — 6,535 Asset-backed securities — 2,484 32 2,516 Government securities — 5,836 — 5,836 Other (3) — 5,365 248 5,613 Total non-U.S. debt securities — 20,220 280 20,500 State and political subdivisions — 10,283 39 10,322 Collateralized mortgage obligations — 2,577 16 2,593 Other U.S. debt securities — 2,469 — 2,469 U.S. equity securities — 42 — 42 Non-U.S. equity securities — 3 — 3 U.S. money-market mutual funds — 409 — 409 Non-U.S. money-market mutual funds — 16 — 16 Total AFS investment securities 3,824 56,837 1,337 61,998 Other assets: Derivatives instruments: Foreign exchange contracts — 16,476 8 $ (9,163 ) 7,321 Interest-rate contracts — 68 — (68 ) — Total derivative instruments — 16,544 8 (9,231 ) 7,321 Total assets carried at fair value $ 4,349 $ 73,880 $ 1,345 $ (9,231 ) $ 70,343 Liabilities: Accrued expenses and other liabilities: Derivative instruments: Foreign exchange contracts $ — $ 15,948 $ 8 $ (10,456 ) $ 5,500 Interest-rate contracts — 348 — (226 ) 122 Other derivative contracts — 380 — — 380 Total derivative instruments — 16,676 8 (10,682 ) 6,002 Total liabilities carried at fair value $ — $ 16,676 $ 8 $ (10,682 ) $ 6,002 (1) Represents counterparty netting against level 2 financial assets and liabilities where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $906 million and $2,356 million , respectively, for cash collateral received from and provided to derivative counterparties. (2) As of December 31, 2016 , the fair value of other ABS was primarily composed of $905 million of CLOs. (3) As of December 31, 2016 , the fair value of other non-U.S. debt securities was primarily composed of $3,769 million of covered bonds and $988 million of corporate bonds. The following tables present activity related to our level 3 financial assets during the years ended December 31, 2017 and 2016 , respectively. Transfers into and out of level 3 are reported as of the beginning of the period presented. During the year ended December 31, 2017 , transfers into level 3 were mainly related to certain ABS and MBS, including non-U.S. debt securities, and municipal loans for which fair value was measured using information obtained from third-party sources, including non-binding broker or dealer quotes. During the years ended December 31, 2017 and 2016 , transfers out of level 3 were mainly related to certain MBS and ABS, including non-U.S. debt securities, for which fair value was measured using prices for which observable market information became available. Fair Value Measurements Using Significant Unobservable Inputs Year Ended December 31, 2017 Fair Value as of Total Realized and Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Fair Value as of December 31, 2017 (1) Change in (In millions) Recorded in Revenue (1) Recorded in Other Comprehensive Income (1) Assets: AFS Investment securities: U.S. Treasury and federal agencies: Mortgage-backed securities $ — $ — $ — $ — $ — $ — $ 25 $ (25 ) $ — Asset-backed securities: Student loans 97 — 1 200 — — — (298 ) — Other 905 3 — 1,035 (240 ) (620 ) 275 — 1,358 Total asset-backed securities 1,002 3 1 1,235 (240 ) (620 ) 275 (298 ) 1,358 Non-U.S. debt securities: Mortgage-backed securities — — (2 ) 119 — 2 — — 119 Asset-backed securities 32 1 — 370 (10 ) (11 ) 67 (47 ) 402 Other 248 — 1 5 (81 ) 31 — — 204 Total non-U.S. debt securities 280 1 (1 ) 494 (91 ) 22 67 (47 ) 725 State and political subdivisions 39 — 2 — — (3 ) 5 — 43 Collateralized mortgage obligations 16 — (1 ) 24 — — — (39 ) — Other U.S. debt securities — — — 19 (19 ) — — — — Total AFS investment securities 1,337 4 1 1,772 (350 ) (601 ) 372 (409 ) 2,126 Other assets: Derivative instruments: Foreign exchange contracts 8 (7 ) — 4 — (4 ) — — 1 $ (3 ) Total derivative instruments 8 (7 ) — 4 — (4 ) — — 1 (3 ) Total assets carried at fair value $ 1,345 $ (3 ) $ 1 $ 1,776 $ (350 ) $ (605 ) $ 372 $ (409 ) $ 2,127 $ (3 ) (1) Total realized and unrealized gains (losses) on AFS investment securities are included within gains (losses) related to investment securities, net. Total realized and unrealized gains (losses) on derivative instruments are included within trading services. Fair Value Measurements Using Significant Unobservable Inputs Year Ended December 31, 2016 Fair Value as of December 31, 2015 Total Realized and Purchases Sales Settlements Transfers Fair Value as of December 31, (2) Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of December 31, 2016 (In millions) Recorded (1) Recorded (1) Assets: AFS Investment securities: U.S. Treasury and federal agencies, mortgage-backed securities $ — $ — $ — $ 325 $ — $ — $ (325 ) $ — Asset-backed securities: Student loans 189 1 3 — $ — — (96 ) 97 Other 1,764 31 (23 ) 469 (82 ) (1,254 ) — 905 Total asset-backed securities 1,953 32 (20 ) 469 (82 ) (1,254 ) (96 ) 1,002 Non-U.S. debt securities: Mortgage-backed securities — — — 90 — — (90 ) — Asset-backed securities 174 — — 196 — (60 ) (278 ) 32 Other 255 — — 222 — (7 ) (222 ) 248 Total non-U.S. debt securities 429 — — 508 — (67 ) (590 ) 280 State and political subdivisions 33 — 9 — — (3 ) — 39 Collateralized mortgage obligations 39 — 2 89 (66 ) (27 ) (21 ) 16 Other U.S. debt securities 10 — — — — (10 ) — — Total AFS investment securities 2,464 32 (9 ) 1,391 (148 ) (1,361 ) (1,032 ) 1,337 Other assets: Derivative instruments: Foreign exchange contracts 5 9 — 3 — (9 ) — 8 $ 5 Total derivative instruments 5 9 — 3 — (9 ) — 8 5 Total assets carried at fair value $ 2,469 $ 41 $ (9 ) $ 1,394 $ (148 ) $ (1,370 ) $ (1,032 ) $ 1,345 $ 5 (1) Total realized and unrealized gains (losses) on AFS investment securities are included within gains (losses) related to investment securities, net. Total realized and unrealized gains (losses) on derivative instruments are included within trading services. (2) There were no transfers of assets into level 3 during the year ended December 31, 2016 . The following table presents quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our level 3 financial assets and liabilities measured at fair value on a recurring basis for which we use internally-developed pricing models. The significant unobservable inputs for our level 3 financial assets and liabilities whose fair value is measured using pricing information from non-binding broker or dealer quotes are not included in the table, as the specific inputs applied are not provided by the broker/dealer. Quantitative Information about Level 3 Fair Value Measurements Fair Value Weighted-Average (Dollars in millions) As of December 31, 2017 As of December 31, 2016 Valuation Technique Significant (1) As of December 31, 2017 As of December 31, 2016 Significant unobservable inputs readily available to State Street: Assets: Asset-backed securities, other $ — $ 1 Discounted cash flows Credit spread — % 0.3 % State and political subdivisions — 39 Discounted cash flows Credit spread — 1.8 Derivative instruments, foreign exchange contracts 1 8 Option model Volatility 7.2 14.4 Total $ 1 $ 48 Liabilities: Derivative instruments, foreign exchange contracts $ 1 $ 8 Option model Volatility 7.2 14.4 Total $ 1 $ 8 (1) Significant chan ges in these unobservable inputs would result in significant changes in fair value measurement. Fair Value Estimates Estimates of fair value for financial instruments not carried at fair value on a recurring basis in our consolidated statement of condition are generally subjective in nature, and are determined as of a specific point in time based on the characteristics of the financial instruments and relevant market information. Disclosure of fair value estimates is not required by U.S. GAAP for certain items, such as lease financing, equity-method investments, obligations for pension and other post-retirement plans, premises and equipment, other intangible assets and income-tax assets and liabilities. Accordingly, aggregate fair-value estimates presented do not purport to represent, and should not be considered representative of, our underlying “market” or franchise value. In addition, because of potential differences in methodologies and assumptions used to estimate fair values, our estimates of fair value should not be compared to those of other financial institutions. We use the following methods to estimate the fair values of our financial instruments: • For financial instruments that have quoted market prices, those quoted prices are used to estimate fair value. • For financial instruments that have no defined maturity, have a remaining maturity of 180 days or less, or reprice frequently to a market rate, we assume that the fair value of these instruments approximates their reported value, after taking into consideration any applicable credit risk. • For financial instruments for which no quoted market prices are available, fair value is estimated using information obtained from independent third parties, or by discounting the expected cash flows using an estimated current market interest rate for the financial instrument. The generally short duration of certain of our assets and liabilities results in a significant number of financial instruments for which fair value equals or closely approximates the amount recorded in our consolidated statement of condition. These financial instruments are reported in the following captions in our consolidated statement of condition: cash and due from banks; interest-bearing deposits with banks; securities purchased under resale agreements; accrued interest and fees receivable; deposits; securities sold under repurchase agreements; and other short-term borrowings. In addition, due to the relatively short duration of certain of our loans, we consider fair value for these loans to approximate their reported value. The fair value of other types of loans, such as senior secured bank loans, commercial real estate loans, purchased receivables and municipal loans is estimated using information obtained from independent third parties or by discounting expected future cash flows using current rates at which similar loans would be made to borrowers with similar credit ratings for the same remaining maturities. Commitments to lend have no reported value because their terms are at prevailing market rates. The following tables present the reported amounts and estimated fair values of the financial assets and liabilities not carried at fair value on a recurring basis, as they would be categorized within the fair value hierarchy, as of the dates indicated. Fair Value Hierarchy (In millions) Reported Amount Estimated Fair Value Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) December 31, 2017 Financial Assets: Cash and due from banks $ 2,107 $ 2,107 $ 2,107 $ — $ — Interest-bearing deposits with banks 67,227 67,227 — 67,227 — Securities purchased under resale agreements 3,241 3,241 — 3,241 — Investment securities held-to-maturity 40,458 40,255 16,814 23,318 123 Net loans (excluding leases) (1) 22,577 22,482 — 22,431 51 Financial Liabilities: Deposits: Non-interest-bearing $ 47,175 $ 47,175 $ — $ 47,175 $ — Interest-bearing - U.S. 50,139 50,139 — 50,139 — Interest-bearing - non-U.S. 87,582 87,582 — 87,582 — Securities sold under repurchase agreements 2,842 2,842 — 2,842 — Other short-term borrowings 1,144 1,144 — 1,144 — Long-term debt 11,620 11,919 — 11,639 280 (1) Includes $3 million of loans classified as held-for-sale that were measured at fair value on a non-recurring basis as of December 31, 2017. Fair Value Hierarchy (In millions) Reported Amount Estimated Fair Value Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) December 31, 2016 Financial Assets: Cash and due from banks $ 1,314 $ 1,314 $ 1,314 $ — $ — Interest-bearing deposits with banks 70,935 70,935 — 70,935 — Securities purchased under resale agreements 1,956 1,956 — 1,956 — Investment securities held-to-maturity 35,169 34,994 17,400 17,439 155 Net loans (excluding leases) 18,862 18,877 — 18,781 96 Financial Liabilities: Deposits: Non-interest-bearing $ 59,397 $ 59,397 $ — $ 59,397 $ — Interest-bearing - U.S. 30,911 30,911 — 30,911 — Interest-bearing - non-U.S. 96,855 96,855 — 96,855 — Securities sold under repurchase agreements 4,400 4,400 — 4,400 — Other short-term borrowings 1,585 1,585 — 1,585 — Long-term debt 11,430 11,618 — 11,282 336

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities Investment securities held by us are classified as either trading, AFS , or HTM at the time of purchase and reassessed periodically, based on management’s intent. Generally, trading assets are debt and equity securities purchased in connection with our trading activities and, as such, are expected to be sold in the near term. Our trading activities typically involve active and frequent buying and selling with the objective of generating profits on short-term movements. AFS investment securities are those securities that we intend to hold for an indefinite period of time. AFS investment securities include securities utilized as part of our asset-and-liability management activities that may be sold in response to changes in interest rates, prepayment risk, liquidity needs or other factors. HTM securities are debt securities that management has the intent and the ability to hold to maturity. Trading assets are carried at fair value. Both realized and unrealized gains and losses on trading assets are recorded in trading services revenue in our consolidated statement of income. Debt and marketable equity securities classified as AFS are carried at fair value, and after-tax net unrealized gains and losses are recorded in AOCI. Gains or losses realized on sales of AFS investment securities are computed using the specific identification method and are recorded in gains (losses) related to investment securities, net, in our consolidated statement of income. HTM investment securities are carried at cost, adjusted for amortization of premiums and accretion of discounts. The following table presents the amortized cost, fair value and associated unrealized gains and losses of investment securities as of the dates indicated: December 31, 2017 December 31, 2016 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value (In millions) Gains Losses Gains Losses Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ 222 $ 2 $ 1 $ 223 $ 4,265 $ 7 $ 9 $ 4,263 Mortgage-backed securities 10,975 26 129 10,872 13,340 76 159 13,257 Total U.S. Treasury and federal agencies 11,197 28 130 11,095 17,605 83 168 17,520 Asset-backed securities: Student loans (1) 3,325 37 4 3,358 5,659 12 75 5,596 Credit cards 1,565 2 25 1,542 1,377 — 26 1,351 Sub-prime — — — — 289 1 18 272 Other (2) 1,440 7 — 1,447 895 10 — 905 Total asset-backed securities 6,330 46 29 6,347 8,220 23 119 8,124 Non-U.S. debt securities: Mortgage-backed securities 6,664 36 5 6,695 6,506 35 6 6,535 Asset-backed securities 2,942 5 — 2,947 2,513 4 1 2,516 Government securities 10,754 16 49 10,721 5,834 8 6 5,836 Other (3) 6,076 38 6 6,108 5,587 31 5 5,613 Total non-U.S. debt securities 26,436 95 60 26,471 20,440 78 18 20,500 State and political subdivisions 8,929 245 23 9,151 10,233 201 112 10,322 Collateralized mortgage obligations 1,060 3 9 1,054 2,610 18 35 2,593 Other U.S. debt securities 2,563 12 15 2,560 2,481 18 30 2,469 U.S. equity securities 40 8 2 46 39 6 3 42 Non-U.S. equity securities — — — — 3 — — 3 U.S. money-market mutual funds 397 — — 397 409 — — 409 Non-U.S. money-market mutual funds — — — — 16 — — 16 Total $ 56,952 $ 437 $ 268 $ 57,121 $ 62,056 $ 427 $ 485 $ 61,998 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 17,028 $ — $ 143 $ 16,885 $ 17,527 $ 17 $ 58 $ 17,486 Mortgage-backed securities 16,651 22 225 16,448 10,334 20 221 10,133 Total U.S. Treasury and federal agencies 33,679 22 368 33,333 27,861 37 279 27,619 Asset-backed securities: Student loans (1) 3,047 32 9 3,070 2,883 5 30 2,858 Credit cards 798 2 — 800 897 2 — 899 Other 1 — — 1 35 — — 35 Total asset-backed securities 3,846 34 9 3,871 3,815 7 30 3,792 Non-U.S. debt securities: Mortgage-backed securities 939 82 6 1,015 1,150 70 15 1,205 Asset-backed securities 263 1 — 264 531 — — 531 Government securities 474 2 — 476 286 3 — 289 Other 48 — — 48 113 1 — 114 Total non-U.S. debt securities 1,724 85 6 1,803 2,080 74 15 2,139 Collateralized mortgage obligations 1,209 45 6 1,248 1,413 42 11 1,444 Total $ 40,458 $ 186 $ 389 $ 40,255 $ 35,169 $ 160 $ 335 $ 34,994 (1) Primarily composed of securities guaranteed by the federal government with respect to at least 97% of defaulted principal and accrued interest on the underlying loans. (2) As of December 31, 2017 and December 31, 2016 , the fair value of other ABS was primarily composed of $1,447 million and $905 million , respectively, of CLOs. (3) As of December 31, 2017 and December 31, 2016 , the fair value of other non-U.S. debt securities was primarily composed of $3,537 million and $3,769 million , respectively, of covered bonds and $1,885 million and $988 million , as of December 31, 2017 and December 31, 2016 , respectively, of corporate bonds. Aggregate investment securities with carrying values of approximately $48 billion and $46 billion as of December 31, 2017 and December 31, 2016 , respectively, were designated as pledged for public and trust deposits, short-term borrowings and for other purposes as provided by law. In 2017 , we sold $12.2 billion of AFS, primarily Agency MBS and U.S. Treasury securities in our investment portfolio, to position for the then-existing interest rate environment resulting in a pre-tax loss of $39 million . In 2017 , $496 million of Agency MBS previously classified as AFS were transferred to HTM, and in 2016 , $4.9 billion , of Agency MBS and Student Loan ABS previously classified as AFS were transferred to HTM. Both transfers reflect our intent to hold these securities until their maturity. These securities were transferred at fair value, which included a net unrealized loss of $2.8 million and a net unrealized gain of $87 million as of December 31, 2017 and 2016 , respectively, within accumulated other comprehensive loss which will be accreted into interest income over the remaining life of the transferred security (ranging from approximately 10 to 42 years). The following tables present the aggregate fair values of investment securities that have been in a continuous unrealized loss position for less than 12 months , and those that have been in a continuous unrealized loss position for 12 months or longer, as of the dates indicated: Less than 12 months 12 months or longer Total December 31, 2017 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses (In millions) Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ — $ — $ 67 $ 1 $ 67 $ 1 Mortgage-backed securities 5,161 31 3,341 98 8,502 129 Total U.S. Treasury and federal agencies 5,161 31 3,408 99 8,569 130 Asset-backed securities: Student loans — — 769 4 769 4 Credit cards 1,289 25 — — 1,289 25 Total asset-backed securities 1,289 25 769 4 2,058 29 Non-U.S. debt securities: Mortgage-backed securities 1,059 4 469 1 1,528 5 Government securities 7,629 48 68 1 7,697 49 Other 816 4 289 2 1,105 6 Total non-U.S. debt securities 9,504 56 826 4 10,330 60 State and political subdivisions 734 6 901 17 1,635 23 Collateralized mortgage obligations 399 5 136 4 535 9 Other U.S. debt securities 1,007 8 345 7 1,352 15 U.S. equity securities — — 6 2 6 2 Total $ 18,094 $ 131 $ 6,391 $ 137 $ 24,485 $ 268 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 14,439 $ 109 $ 2,447 $ 34 $ 16,886 $ 143 Mortgage-backed securities 6,785 38 5,988 187 12,773 225 Total U.S. Treasury and federal agencies 21,224 147 8,435 221 29,659 368 Asset-backed securities: Student loans 440 3 423 6 863 9 Total asset-backed securities 440 3 423 6 863 9 Non-U.S. debt securities: Mortgage-backed securities — — 239 6 239 6 Total non-U.S. debt securities — — 239 6 239 6 Collateralized mortgage obligations — — 276 6 276 6 Total $ 21,664 $ 150 $ 9,373 $ 239 $ 31,037 $ 389 Less than 12 months 12 months or longer Total December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses (In millions) Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ 651 $ 8 $ 180 $ 1 $ 831 $ 9 Mortgage-backed securities 7,072 131 1,114 28 8,186 159 Total U.S. Treasury and federal agencies 7,723 139 1,294 29 9,017 168 Asset-backed securities: Student loans 54 — 3,745 75 3,799 75 Credit cards 795 1 494 25 1,289 26 Sub-prime 1 — 252 18 253 18 Other 75 — — — 75 — Total asset-backed securities 925 1 4,491 118 5,416 119 Non-U.S. debt securities: Mortgage-backed securities 442 1 893 5 1,335 6 Asset-backed securities 253 — 276 1 529 1 Government securities 1,314 6 — — 1,314 6 Other 670 4 218 1 888 5 Total non-U.S. debt securities 2,679 11 1,387 7 4,066 18 State and political subdivisions 3,390 102 304 10 3,694 112 Collateralized mortgage obligations 1,259 31 162 4 1,421 35 Other U.S. debt securities 944 24 157 6 1,101 30 U.S. equity securities 8 — 5 3 13 3 Total $ 16,928 $ 308 $ 7,800 $ 177 $ 24,728 $ 485 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 8,891 $ 57 $ 86 $ 1 $ 8,977 $ 58 Mortgage-backed securities 6,838 221 — — 6,838 221 Total U.S. Treasury and federal agencies 15,729 278 86 1 15,815 279 Asset-backed securities: Student loans 705 9 1,235 21 1,940 30 Credit cards 33 — — — 33 — Other 18 — 9 — 27 — Total asset-backed securities 756 9 1,244 21 2,000 30 Non-U.S. debt securities: Mortgage-backed securities 54 2 330 13 384 15 Asset-backed securities 28 — 35 — 63 — Government securities 180 — — — 180 — Total non-U.S. debt securities 262 2 365 13 627 15 Collateralized mortgage obligations 537 4 204 7 741 11 Total $ 17,284 $ 293 $ 1,899 $ 42 $ 19,183 $ 335 The following table presents contractual maturities of debt investment securities by carrying amount as of December 31, 2017 . The maturities of certain ABS, MBS, and CMOs are based on expected principal payments. Actual maturities may differ from these expected maturities since certain borrowers have the right to prepay obligations with or without prepayment penalties. December 31, 2017 Under 1 Year 1 to 5 Years 6 to 10 Years Over 10 Years Total (In millions) Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ — $ 12 $ 6 $ 205 $ 223 Mortgage-backed securities 96 762 3,123 6,891 10,872 Total U.S. Treasury and federal agencies 96 774 3,129 7,096 11,095 Asset-backed securities: Student loans 289 1,044 685 1,340 3,358 Credit cards — 1,290 252 — 1,542 Other — 350 956 141 1,447 Total asset-backed securities 289 2,684 1,893 1,481 6,347 Non-U.S. debt securities: Mortgage-backed securities 551 4,502 602 1,040 6,695 Asset-backed securities 205 2,185 557 — 2,947 Government securities 2,195 3,201 4,448 877 10,721 Other 1,078 4,235 758 37 6,108 Total non-U.S. debt securities 4,029 14,123 6,365 1,954 26,471 State and political subdivisions 474 2,415 4,724 1,538 9,151 Collateralized mortgage obligations 3 145 170 736 1,054 Other U.S. debt securities 296 1,097 1,107 60 2,560 Total $ 5,187 $ 21,238 $ 17,388 $ 12,865 $ 56,678 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 1,988 $ 14,968 $ 14 $ 58 $ 17,028 Mortgage-backed securities — 162 1,605 14,884 16,651 Total U.S. Treasury and federal agencies 1,988 15,130 1,619 14,942 33,679 Asset-backed securities: Student loans 35 245 265 2,502 3,047 Credit cards 178 620 — — 798 Other — — — 1 1 Total asset-backed securities 213 865 265 2,503 3,846 Non-U.S. debt securities: Mortgage-backed securities 132 217 45 545 939 Asset-backed securities 26 237 — — 263 Government securities 353 121 — — 474 Other — 48 — — 48 Total non-U.S. debt securities 511 623 45 545 1,724 Collateralized mortgage obligations 8 144 343 714 1,209 Total $ 2,720 $ 16,762 $ 2,272 $ 18,704 $ 40,458 The following tables present gross realized gains and losses from sales of AFS investment securities, and the components of net impairment losses included in net gains and losses related to investment securities for the periods indicated. Years Ended December 31, (In millions) 2017 2016 2015 Gross realized gains from sales of AFS investment securities $ 74 $ 15 $ 57 Gross realized losses from sales of AFS investment securities (113 ) (5 ) (62 ) Net impairment losses: Gross losses from OTTI — (2 ) (1 ) Losses reclassified (from) to other comprehensive income — (1 ) — Net impairment losses (1) — (3 ) (1 ) Gains (losses) related to investment securities, net $ (39 ) $ 7 $ (6 ) (1) Net impairment losses, recognized in our consolidated statement of income, were composed of the following: Impairment associated with expected credit losses $ — $ (1 ) $ — Impairment associated with adverse changes in timing of expected future cash flows — (2 ) (1 ) Net impairment losses $ — $ (3 ) $ (1 ) The following table presents a roll-forward with respect to net impairment losses that have been recognized in income for the periods indicated. Years Ended December 31, (In millions) 2017 2016 2015 Balance, beginning of period $ 66 $ 92 $ 115 Additions: Losses for which OTTI was previously recognized — 2 1 Deductions: Previously recognized losses related to securities sold or matured (2 ) (28 ) (24 ) Balance, end of period $ 64 $ 66 $ 92 Interest income related to debt securities is recognized in our consolidated statement of income using the effective interest method, or on a basis approximating a level rate of return over the contractual or estimated life of the security. The level rate of return considers any non-refundable fees or costs, as well as purchase premiums or discounts, resulting in amortization or accretion, accordingly. For certain debt securities acquired which are considered to be beneficial interests in securitized financial assets, the excess of our estimate of undiscounted future cash flows from these securities over their initial recorded investment is accreted into interest income on a level-yield basis over the securities’ estimated remaining terms. Subsequent decreases in these securities’ expected future cash flows are either recognized prospectively through an adjustment of the yields on the securities over their remaining terms, or are evaluated for OTTI. Increases in expected future cash flows are recognized prospectively over the securities’ estimated remaining terms through the recalculation of their yields. Impairment We conduct periodic reviews of individual securities to assess whether OTTI exists. Impairment exists when the current fair value of an individual security is below its amortized cost basis. For AFS and HTM debt securities, impairment is recorded in our consolidated statement of income when management intends to sell (or may be required to sell) the securities before they recover in value, or when management expects the present value of cash flows expected to be collected from the securities to be less than the amortized cost of the impaired security (a credit loss). Our review of impaired securities generally includes: • the identification and evaluation of securities that have indications of potential OTTI, such as issuer-specific concerns, including deteriorating financial condition or bankruptcy; • the analysis of expected future cash flows of securities, based on quantitative and qualitative factors; • the analysis of the collectability of those future cash flows, including information about past events, current conditions, and reasonable and supportable forecasts; • the analysis of the underlying collateral for MBS and ABS; • the analysis of individual impaired securities, including consideration of the length of time the security has been in an unrealized loss position, the anticipated recovery period, and the magnitude of the overall price decline; • evaluation of factors or triggers that could cause individual securities to be deemed OTTI and those that would not support OTTI; and • documentation of the results of these analyses. Factors considered in determining whether impairment is other than temporary include: • certain macroeconomic drivers; • certain industry-specific drivers; • the length of time the security has been impaired; • the severity of the impairment; • the cause of the impairment and the financial condition and near-term prospects of the issuer; • activity in the market with respect to the issuer's securities, which may indicate adverse credit conditions; and • our intention not to sell, and the likelihood that we will not be required to sell, the security for a period of time sufficient to allow for its recovery in value. Substantially all of our investment securities portfolio is composed of debt securities. A critical component of our assessment of OTTI of these debt securities is the identification of credit-impaired securities for which management does not expect to receive cash flows sufficient to recover the entire amortized cost basis of the security. Debt securities that are not deemed to be credit-impaired are subject to additional management analysis to assess whether management intends to sell, or, more likely than not, would be required to sell, the security before the expected recovery of its amortized cost basis. The following provides a description of our process for the identification and assessment of OTTI, as well as information about OTTI recorded in 2017 , 2016 and 2015 and changes in period-end unrealized losses, for major security types as of December 31, 2017 . U.S. Agency Securities Our portfolio of U.S. agency direct obligations and MBS receives the implicit or explicit backing of the U.S. government in conjunction with specified financial support of the U.S. Treasury. We recorded no OTTI on these securities in 2017 , 2016 or 2015 . The overall increase in the unrealized losses on these securities as of December 31, 2017 was primarily attributable to interest rate increases in 2017 . Asset-Backed Securities - Student Loans Asset-backed securities collateralized by student loans are primarily composed of securities collateralized by FFELP loans. FFELP loans benefit from a federal government guarantee of at least 97% of defaulted principal and accrued interest, with additional credit support provided to our securities in the form of over-collateralization, subordination and excess spread, which collectively total in excess of 100%. Accordingly, the vast majority of FFELP loan-backed securities are protected from traditional consumer credit risk. We recorded no OTTI on these securities in 2017, 2016 or 2015.The improvement in the mark to market for our FFELP loan-backed securities portfolio as of December 31, 2017 was primarily attributable to the tightening FFELP spreads. Our assessment of OTTI of these securities considers, among many other factors, the strength of the U.S. government guarantee, the performance of the underlying collateral, and the remaining average term of the FFELP loan-backed securities portfolio, which was approximately 4.6 years as of December 31, 2017. In general, the rating agencies have largely completed their downgrade review of FFELP loan-backed securities due to potential extension of student loan repayments beyond the securities’ legal final maturity dates. At this time, we do not expect a significant number of additional downgrades related to potential legal final maturity breaches. Based on the limited price impact on the overall FFELP loan-backed securities portfolio and recent remedial actions by issuers, including amending loan-backed securities’ maturity dates and exercising cleanup calls, the credit quality of the FFELP loan-backed securities portfolio remains stable and we, as a bondholder, remain protected from principal loss as a result of the aforementioned federal government guarantee and over-collateralization. Downside risks remain should remedial actions fail to address the extension risks. Our total exposure to private student loan-backed securities was less than $70 million as of December 31, 2017. Our assessment of OTTI of private student loan-backed securities considers, among other factors, the impact of high unemployment rates on the collateral performance of private student loans. We recorded no OTTI on these securities in 2017, 2016 or 2015. Non-U.S. Mortgage- and Asset-Backed Securities Non-U.S. mortgage- and asset-backed securities are primarily composed of U.K., Australian and Dutch securities collateralized by residential mortgages and German and U.K. securities collateralized by automobile loans and leases. Our assessment of impairment with respect to these securities considers the location of the underlying collateral, collateral enhancement and structural features, expected credit losses under base-case and stressed conditions and the macroeconomic outlook for the country in which the collateral is located, including housing prices and unemployment. Where appropriate, any potential loss after consideration of the above-referenced factors is further evaluated to determine whether any OTTI exists. We recorded OTTI of less than $1 million , $2 million and $1 million in 2017, 2016 and 2015, respectively, on non-U.S. residential MBS, which resulted from adverse changes in the timing of expected future cash flows from the securities. Our assessment of OTTI of these securities takes into account government intervention in the corresponding mortgage markets and assumes a baseline macroeconomic environment for this region, factoring in slower economic growth and continued government austerity measures. In addition, we perform stress testing and sensitivity analysis in order to understand the impact of more severe assumptions on potential OTTI. State and Political Subdivisions and Other U.S. Debt Securities Our municipal securities portfolio primarily includes securities issued by U.S. states and their municipalities. A portion of this portfolio is held in connection with our tax-exempt investment program, more fully described in Note 14 . Our portfolio of other U.S. debt securities is primarily composed of securities issued by U.S. corporations. Our assessment of OTTI of these portfolios considers, among other factors, adverse conditions specifically related to the industry, geographic area or financial condition of the issuer; the structure of the security, including collateral, if any, and payment schedule; rating agency changes to the security's credit rating; the volatility of the fair value changes; and our intent and ability to hold the security until its recovery in value. If the impairment of the security is credit-related, we estimate the future cash flows from the security, tailored to the security and considering the above-described factors, and any resulting impairment deemed to be other-than-temporary is recorded in our consolidated statement of income. We recorded no OTTI on these securities in 2017 , 2016 or 2015 . The decline in the unrealized losses on these securities as of December 31, 2017 was primarily attributable to the narrowing of spreads and U.S. Treasury rates in 2017 . U.S. Non-Agency Residential Mortgage-Backed Securities We assess OTTI of our portfolio of U.S. non-agency residential mortgage-backed securities using cash flow models, tailored for each security, that estimate the future cash flows from the underlying mortgages, using the security-specific collateral and transaction structure. Estimates of future cash flows are subject to management judgment. The future cash flows and performance of our portfolio of U.S. non-agency residential mortgage-backed securities are a function of a number of factors, including, but not limited to, the condition of the U.S. economy, the condition of the U.S. residential mortgage markets, and the level of loan defaults, prepayments and loss severities. Management's estimates of future losses for each security also consider the underwriting and historical performance of each specific security, the underlying collateral type, vintage, borrower profile, third-party guarantees, current levels of subordination, geography and other factors. We recorded no OTTI on these securities in 2017 , 2016 or 2015 . U.S. Non-Agency Commercial Mortgage-Backed Securities With respect to our portfolio of U.S. non-agency commercial mortgage-backed securities, OTTI is assessed by considering a number of factors, including, but not limited to, the condition of the U.S. economy and the condition of the U.S. commercial real estate market, as well as capitalization rates. Management estimates of future losses for each security also consider the underlying collateral type, property location, vintage, debt-service coverage ratios, expected property income, servicer advances and estimated property values, as well as current levels of subordination. We recorded no OTTI on these securities in 2017 and 2015. In 2016 we recorded $1 million of OTTI on these securities, all associated with expected credit losses. The estimates, assumptions and other risk factors utilized in our assessment of impairment as described above are used by management to identify securities which are subject to further analysis of potential credit losses. Additional analyses are performed using more stressful assumptions to further evaluate the sensitivity of losses relative to the above-described factors. However, since the assumptions are based on the unique characteristics of each security, management uses a range of estimates for prepayment speeds, default, and loss severity forecasts that reflect the collateral profile of the securities within each asset class. In addition, in measuring expected credit losses, the individual characteristics of each security are examined to determine whether any additional factors would increase or mitigate the expected loss. Once losses are determined, the timing of the loss will also affect the ultimate OTTI, since the loss is ultimately subject to a discount commensurate with the purchase yield of the security. After a review of the investment portfolio, taking into consideration current economic conditions, adverse situations that might affect our ability to fully collect principal and interest, the timing of future payments, the credit quality and performance of the collateral underlying MBS and ABS and other relevant factors, management considers the aggregate decline in fair value of the investment securities portfolio and the resulting gross pre-tax unrealized losses of $657 million related to 1,283 securities as of December 31, 2017 to be temporary, and not the result of any material changes in the credit characteristics of the securities.

Loans and Leases

Loans and Leases	12 Months Ended
	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases	Loans and Leases Loans are generally recorded at their principal amount outstanding, net of the allowance for loan losses, unearned income, and any net unamortized deferred loan origination fees. Acquired loans have been initially recorded at fair value based on management's expectation with respect to future principal and interest collection as of the date of acquisition. Acquired loans are held for investment, and as such their initial fair value is not adjusted subsequent to acquisition. Loans that are classified as held-for-sale are measured at lower of cost or fair value on an individual basis. Interest income related to loans is recognized in our consolidated statement of income using the interest method, or on a basis approximating a level rate of return over the term of the loan. Fees received for providing loan commitments and letters of credit that we anticipate will result in loans typically are deferred and amortized to interest income over the term of the related loan, beginning with the initial borrowing. Fees on commitments and letters of credit are amortized to processing fees and other revenue over the commitment period when funding is not known or expected. Leveraged-lease investments are reported at the aggregate of lease payments receivable and estimated residual values, net of non-recourse debt and unearned income. Lease residual values are reviewed regularly for OTTI, with valuation adjustments recorded against processing fees and other revenue. Unearned income is recognized to yield a level rate of return on the net investment in the leases. Gains and losses on residual values of leased equipment sold are recorded in processing fees and other revenue. The following table presents our recorded investment in loans and leases, by segment, as of the dates indicated: (In millions) December 31, 2017 December 31, 2016 Domestic: Commercial and financial: Loans to investment funds $ 13,618 $ 11,734 Senior secured bank loans 2,923 3,256 Loans to municipalities 2,105 1,352 Other 50 70 Commercial real estate 98 27 Lease financing 267 338 Total domestic 19,061 16,777 Non-U.S.: Commercial and financial: Loans to investment funds 3,213 2,224 Senior secured bank loans 624 252 Lease financing 396 504 Total non-U.S. 4,233 2,980 Total loans and leases 23,294 19,757 Allowance for loan and lease losses (54 ) (53 ) Loans and leases, net of allowance $ 23,240 $ 19,704 We segregate our loans and leases into three segments: commercial and financial loans, commercial real estate loans, and lease financing. We further classify commercial and financial loans as loans to investment funds, senior secured bank loans, loans to municipalities, and other. These classifications reflect their risk characteristics, their initial measurement attributes and the methods we use to monitor and assess credit risk. The commercial and financial segment is composed of primarily floating-rate loans to mutual fund clients, purchased senior secured bank loans, and loans to municipalities. Investment fund lending is composed of short-duration revolving credit lines providing liquidity to fund clients in support of their transaction flows associated with securities' settlement activities. Certain loans are pledged as collateral for access to the Federal Reserve's discount window. As of December 31, 2017 and December 31, 2016 , the loans pledged as collateral totaled $1.9 billion and $1.5 billion , respectively. The lease financing segment includes our investment in leveraged lease financing. The components of our net investment in leveraged lease financing, included in the lease financing segment in the preceding table, were as follows as of December 31, 2017 and December 31, 2016: (In millions) 2017 2016 Net rental income receivable $ 808 $ 1,039 Estimated residual values 89 89 Unearned income (234 ) (286 ) Investment in leveraged lease financing 663 842 Less: related deferred income tax liabilities (184 ) (313 ) Net investment in leveraged lease financing $ 479 $ 529 The following tables present our recorded investment in each class of loans and leases by credit quality indicator as of the dates indicated: December 31, 2017 Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases (In millions) Investment grade (1) $ 17,866 $ 98 $ 663 $ 18,627 Speculative (2) 4,638 — — 4,638 Special mention (3) 29 — — 29 Total $ 22,533 $ 98 $ 663 $ 23,294 December 31, 2016 Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases (In millions) Investment grade (1) $ 14,889 $ 27 $ 842 $ 15,758 Speculative (2) 3,984 — — 3,984 Substandard (4) 15 — — 15 Total $ 18,888 $ 27 $ 842 $ 19,757 (1) Investment-grade loans and leases consist of counterparties with strong credit quality and low expected credit risk and probability of default. Ratings apply to counterparties with a strong capacity to support the timely repayment of any financial commitment. (2) Speculative loans and leases consist of counterparties that face ongoing uncertainties or exposure to business, financial, or economic downturns. However, these counterparties may have financial flexibility or access to financial alternatives, which allow for financial commitments to be met. (3) Special mention loans and leases consist of counterparties with potential weaknesses that, if uncorrected, may result in deterioration of repayment prospects. (4) Substandard loans and leases consist of counterparties with well-defined weakness that jeopardizes repayment with the possibility we will sustain some loss We use an internal risk-rating system to assess our risk of credit loss for each loan or lease. This risk-rating process incorporates the use of risk-rating tools in conjunction with management judgment. Qualitative and quantitative inputs are captured in a systematic manner, and following a formal review and approval process, an internal credit rating based on our credit scale is assigned. In assessing the risk rating assigned to each individual loan or lease, among the factors considered are the borrower's debt capacity, collateral coverage, payment history and delinquency experience, financial flexibility and earnings strength, the expected amounts and source of repayment, the level and nature of contingencies, if any, and the industry and geography in which the borrower operates. These factors are based on an evaluation of historical and current information, and involve subjective assessment and interpretation. Credit counterparties are evaluated and risk-rated on an individual basis at least annually. Management considers the ratings to be current as of December 31, 2017 . The following table presents our recorded investment in loans and leases, disaggregated based on our impairment methodology, as of the dates indicated: December 31, 2017 December 31, 2016 (In millions) Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases Loans and leases (1) : Individually evaluated for impairment $ — $ — $ — $ — $ 15 $ — $ — $ 15 Collectively evaluated for impairment 22,533 98 663 23,294 18,873 27 842 19,742 Total $ 22,533 $ 98 $ 663 $ 23,294 $ 18,888 $ 27 $ 842 $ 19,757 (1) For those portfolios where there are a small number of loans each with a large balance, we review each loan annually for indicators of impairment. For those loans where no such indicators are identified, the loans are collectively evaluated for impairment. As of December 31, 2017 , no loans were individually evaluated for impairment. As of December 31, 2016 , $195 thousand of the allowance for loan and lease loss related to commercial and financial loans were individually evaluated for impairment, and the remainder of the allowance related to commercial and financial loans collectively evaluated for impairment. As of December 31, 2017 , we had no impaired loans and leases. As of December 31, 2016 , we identified one commercial and financial loan as impaired, with both a recorded investment and unpaid principal balance of $15 million . The impaired loan had zero related interest income and an associated allowance for loan losses of $0.2 million . In certain circumstances, we restructure troubled loans by granting concessions to borrowers experiencing financial difficulty. Once restructured, the loans are generally considered impaired until their maturity, regardless of whether the borrowers perform under the modified terms of the loans. No loans were modified in troubled debt restructurings during the years ended December 31, 2017 and December 31, 2016 . We generally place loans on non-accrual status once principal or interest payments are 90 days contractually past due, or earlier if management determines that full collection is not probable. Loans 90 days past due, but considered both well-secured and in the process of collection, may be excluded from non-accrual status. When we place a loan on non-accrual status, the accrual of interest is discontinued and previously recorded but unpaid interest is reversed and generally charged against interest income. For loans on non-accrual status, income is recognized on a cash basis after recovery of principal, if and when interest payments are received. Loans may be removed from non-accrual status when repayment is reasonably assured and performance under the terms of the loan has been demonstrated. As of December 31, 2017 , there were no loans or leases on non-accrual status. As of December 31, 2016 , there was one commercial and financial loan on non-accrual status, and no CRE loans or leases were on non-accrual status. As of both December 31, 2017 and 2016 there were no loans or leases 90 days or more contractually past due. Allowance For Loan And Lease Losses The allowance for loan and lease losses, recorded as a reduction of loans and leases in our consolidated statement of condition, represents management’s estimate of incurred credit losses in our loan and lease portfolio as of the balance sheet date. The allowance is evaluated on a regular basis by management. Factors considered in evaluating the appropriate level of the allowance for each segment of our loan-and-lease portfolio include loss experience, the probability of default reflected in our internal risk rating of the counterparty's creditworthiness, current economic conditions and adverse situations that may affect the borrower’s ability to repay, the estimated value of the underlying collateral, if any, the performance of individual credits in relation to contract terms, and other relevant factors. Loans and leases are charged off to the allowance for loan and lease losses in the reporting period in which either an event occurs that confirms the existence of a loss on a loan or lease or a portion of a loan or lease is determined to be uncollectible. In addition, any impaired loan or lease that is determined to be collateral-dependent is reduced to an amount equal to the fair value of the collateral less costs to sell. A loan or lease is identified as collateral-dependent when management determines that it is probable that the underlying collateral will be the sole source of repayment. Recoveries are recorded on a cash basis as adjustments to the allowance. The following table presents activity in the allowance for loan and lease losses for the periods indicated: Years Ended December 31, 2017 2016 2015 (In millions) Total Loans and Leases Total Loans and Leases Total Loans and Leases Allowance for loan and lease losses (1) : Beginning balance $ 53 $ 46 $ 38 Provision for loan and lease losses 2 10 12 Charge-offs (1 ) (3 ) (4 ) Ending balance $ 54 $ 53 $ 46 (1) The provisions and charge-offs for loans and leases were attributable to exposure to senior secured loans to non-investment grade borrowers, purchased in connection with our participation in syndicated loans. Loans and leases are reviewed on a regular basis, and any provisions for loan and lease losses that are recorded reflect management's estimate of the amount necessary to maintain the allowance for loan and lease losses at a level considered appropriate to absorb estimated incurred losses in the loan and lease portfolio. Off-Balance Sheet Credit Exposures The reserve for off-balance sheet credit exposures, recorded in accrued expenses and other liabilities in our consolidated statement of condition, represents management’s estimate of probable credit losses in outstanding letters and lines of credit and other credit-enhancement facilities provided to our clients and outstanding as of the balance sheet date. The reserve is evaluated on a regular basis by management. Factors considered in evaluating the appropriate level of this reserve are similar to those considered with respect to the allowance for loan and lease losses. Provisions to maintain the reserve at a level considered by us to be appropriate to absorb estimated incurred credit losses in outstanding facilities are recorded in other expenses in our consolidated statement of income.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess of the cost of an acquisition over the fair value of the net tangible and other intangible assets acquired. Other intangible assets represent purchased long-lived intangible assets, primarily client relationships and core deposit intangible assets, that can be distinguished from goodwill because of contractual rights or because the asset can be exchanged on its own or in combination with a related contract, asset or liability. Goodwill is not amortized, but is subject to at least annual evaluation for impairment. Other intangible assets, which are also subject to annual evaluation for impairment, are mainly related to client relationships, which are amortized on a straight-line basis over periods ranging from five to twenty years, and core deposit intangible assets, which are amortized on a straight-line basis over periods ranging from sixteen to twenty-two years, with such amortization recorded in other expenses in our consolidated statement of income. Impairment of goodwill is deemed to exist if the carrying value of a reporting unit, including its allocation of goodwill and other intangible assets, exceeds its estimated fair value. Impairment of other intangible assets is deemed to exist if the balance of the other intangible asset exceeds the cumulative expected net cash inflows related to the asset over its remaining estimated useful life. If these reviews determine that goodwill or other intangible assets are impaired, the value of the goodwill or the other intangible asset is written down through a charge to other expenses in our consolidated statement of income. The following table presents changes in the carrying amount of goodwill during the periods indicated: (In millions) Investment Servicing Investment Management Total Goodwill: Ending balance December 31, 2015 $ 5,641 $ 30 $ 5,671 Acquisitions (1) — 236 236 Divestitures and other reductions (11 ) — (11 ) Foreign currency translation (80 ) (2 ) (82 ) Ending balance December 31, 2016 $ 5,550 $ 264 $ 5,814 Acquisitions 17 — 17 Divestitures and other reductions (9 ) — (9 ) Foreign currency translation 194 6 200 Ending balance December 31, 2017 $ 5,752 $ 270 $ 6,022 (1) Investment Management includes our acquisition of the GEAM business on July 1, 2016, which is described in Note 1. The following table presents changes in the net carrying amount of other intangible assets during the periods indicated: (In millions) Investment Servicing Investment Management Total Other intangible assets: Ending balance December 31, 2015 $ 1,753 $ 15 $ 1,768 Acquisitions (1) — 217 217 Divestitures (8 ) — (8 ) Amortization (186 ) (21 ) (207 ) Foreign currency translation and other, net (20 ) — (20 ) Ending balance December 31, 2016 $ 1,539 $ 211 $ 1,750 Acquisitions 16 — 16 Divestitures (11 ) — (11 ) Amortization (183 ) (31 ) (214 ) Foreign currency translation and other, net 71 1 72 Ending balance December 31, 2017 $ 1,432 $ 181 $ 1,613 (1) Investment Management includes our acquisition of the GEAM business on July 1, 2016, which is described in Note 1. The following table presents the gross carrying amount, accumulated amortization and net carrying amount of other intangible assets by type as of the dates indicated: December 31, 2017 December 31, 2016 (In millions) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Other intangible assets: Client relationships $ 2,669 $ (1,470 ) $ 1,199 $ 2,620 $ (1,306 ) $ 1,314 Core deposits 686 (320 ) 366 661 (277 ) 384 Other 142 (94 ) 48 132 (80 ) 52 Total $ 3,497 $ (1,884 ) $ 1,613 $ 3,413 $ (1,663 ) $ 1,750 Amortization expense related to other intangible assets was $214 million , $207 million and $197 million in 2017 , 2016 and 2015 , respectively. Expected future amortization expense for other intangible assets recorded as of December 31, 2017 is as follows: (In millions) Future Amortization Years Ending December 31, 2018 $ 191 2019 174 2020 171 2021 166 2022 165

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2017
Other Assets [Abstract]
Other Assets	Other Assets The following table presents the components of other assets as of the dates indicated: (In millions) December 31, 2017 December 31, 2016 Receivable - securities lending (1) $ 19,404 $ 21,204 Derivative instruments, net 4,013 7,321 Bank-owned life insurance 3,242 3,158 Investments in joint ventures and other unconsolidated entities 2,259 2,363 Collateral, net 473 2,236 Prepaid expenses 364 333 Accounts receivable 348 886 Receivable for securities settlement 188 40 Deposits with clearing organizations 120 132 Deferred tax assets, net of valuation allowance (2) 113 210 Income taxes receivable 97 106 Other (3) 397 339 Total $ 31,018 $ 38,328 (1) Refer to Note 11 for further information on the impact of collateral on our financial statement presentation of securities borrowing transactions. (2) Deferred tax assets and liabilities recorded in our consolidated statement of condition are netted within the same tax jurisdiction. Gross deferred tax assets and liabilities are presented in Note 22 . (3) In 2017, includes amounts held in escrow accounts at third parties related to the negotiated settlements in the transition management legal matter presented in Note 13 .

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Deposits	Deposits As of December 31, 2017 , we had $39.73 billion of time deposits outstanding, of which $4.75 billion were wholesale CDs, $34.73 billion were derived from client deposits (payable on demand to such clients) and held in a time deposit established by State Street as the agent, and $252 million were non-U.S. and all of which are scheduled to mature in 2018. As of December 31, 2016 , we had $55.03 billion of time deposits outstanding, of which $214 million were non-U.S. As of December 31, 2017 and 2016 , substantially all U.S. and non-U.S. time deposits were in amounts of $100,000 or more. Demand deposit overdrafts of $3.24 billion and $2.62 billion were included as loan balances at December 31, 2017 and 2016 , respectively.

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Short-Term Borrowings	Short-Term Borrowings Our short-term borrowings include securities sold under repurchase agreements, federal funds purchased and other short-term borrowings; other short-term borrowings include borrowings associated with our tax-exempt investment program, more fully described in Note 14 . Collectively, short-term borrowings had weighted-average interest rates of 0.25% and 0.13% in 2017 and 2016 , respectively. The following tables present information with respect to the amounts outstanding and weighted-average interest rates of the primary components of our short-term borrowings as of and for the years ended December 31 : Securities Sold Under Repurchase Agreements Federal Funds Purchased Tax-Exempt Investment Program (Dollars in millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Balance as of December 31 $ 2,842 $ 4,400 $ 4,499 $ — $ — $ 6 $ 1,078 $ 1,158 $ 1,748 Maximum outstanding as of any month-end 4,302 5,572 10,977 — 29 29 1,158 1,726 1,865 Average outstanding during the year 3,683 4,113 8,875 1 31 21 1,127 1,512 1,807 Weighted-average interest rate as of year-end .03 % .04 % .02 % .00 % .00 % .03 % 1.45 % .67 % .03 % Weighted-average interest rate during the year .05 .02 .01 .00 .17 .01 .79 .36 .06 Obligations to repurchase securities sold are recorded as a liability in our consolidated statement of condition. U.S. government securities with a fair value of $2.90 billion underlying the repurchase agreements remained in our investment securities portfolio as of December 31, 2017 . The following table presents information about these U.S. government securities and the carrying value of the related repurchase agreements, including accrued interest, as of December 31, 2017 . The table excludes repurchase agreements collateralized by securities purchased under resale agreements and collateralized by trading account assets. U.S. Government Securities Sold Repurchase Agreements (1) (In millions) Amortized Cost Fair Value Amortized Cost Overnight maturity $ 2,928 $ 2,899 $ 2,842 (1) Collateralized by investment securities. We maintain an agreement with a clearing organization that enables us to net all securities purchased under resale agreements and sold under repurchase agreements with counterparties that are also members of the clearing organization. As a result of this netting, the average balances of securities purchased under resale agreements and securities sold under repurchase agreements were reduced by $31.15 billion in 2017 compared to $30.86 billion in 2016 . State Street Bank currently maintains a line of credit of CAD 1.40 billion , or approximately $1.11 billion as of December 31, 2017 , to support its Canadian securities processing operations. The line of credit has no stated termination date and is cancelable by either party with prior notice. As of December 31, 2017 and 2016 , there was no balance outstanding on this line of credit.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2017
Long-term Debt, Unclassified [Abstract]
Long-Term Debt	Long-Term Debt (Dollars in millions) As of December 31, Issuance Date Maturity Date Coupon Rate Seniority Interest Due Dates 2017 2016 Parent Company And Non-Banking Subsidiary Issuances August 18, 2015 August 18, 2025 3.55 % Senior notes 2/18; 8/18 (1) 1,287 1,293 August 18, 2015 August 18, 2020 2.55 % Senior notes 2/18; 8/18 (1) 1,184 1,192 November 19, 2013 November 20, 2023 3.7 % Senior notes 5/20; 11/20 (1) 1,021 1,033 December 15, 2014 December 16, 2024 3.3 % Senior notes 6/16; 12/16 (1) 993 999 May 15, 2013 May 15, 2023 (2) 3.1 % Subordinated notes 5/15; 11/15 (1) 981 987 April 30, 2007 June 15, 2047 Floating-rate Junior subordinated debentures 3/15; 6/15; 9/15; 12/15 793 793 May 15, 2017 May 15, 2023 2.653 % Fixed to Floating Rate Senior notes 5/15; 11/15 (1) 740 — March 7, 2011 March 7, 2021 4.375 % Senior notes 3/7; 9/7 (1) 734 738 May 19, 2016 May 19, 2021 1.95 % Senior notes 5/19; 11/19 (1) 724 726 May 19, 2016 May 19, 2026 2.65 % Senior notes 5/19; 11/19 (1) 706 704 February 11, 2011 March 15, 2018 (3) 4.956 % Junior subordinated debentures 3/15; 9/15 502 511 August 18, 2015 August 18, 2020 Floating-rate Senior notes 2/18; 5/18; 8/18; 11/18 499 499 May 15, 2013 May 15, 2018 1.35 % Senior notes 5/15; 11/15 499 497 May 15, 1998 May 15, 2028 Floating-rate Junior subordinated debentures 2/15; 5/15; 8/15; 11/15 150 150 June 21, 1996 June 15, 2026 (4) 7.35 % Senior notes 6/15; 12/15 150 150 April 30, 2007 April 30, 2017 5.375 % Senior notes 4/30; 10/30 — 450 Parent Company Long-term capital leases 250 293 State Street Bank issuances September 24, 2003 October 15, 2018 (2) 5.25 % Subordinated notes 4/15; 10/15 407 415 Total long-term debt $ 11,620 $ 11,430 (1) We have entered into interest-rate swap agreements, recorded as fair value hedges, to modify our interest expense on these senior and subordinated notes from a fixed rate to a floating rate. As of December 31, 2017 and December 31, 2016 , the carrying value of long-term debt associated with these fair value hedges decreased $87 million and $15 million , respectively. Refer to Note 10 for additional information about fair value hedges. (2) The subordinated notes qualify for inclusion in tier 2 regulatory capital under current federal regulatory capital guidelines. (3) We do not have the right to redeem the debenture prior to maturity other than upon the occurrence of specified events. Such redemption is subject to federal regulatory approval. The junior subordinated debentures qualify for inclusion in tier 2 regulatory capital under current federal regulatory capital guidelines. (4) We may not redeem notes prior to their maturity. Parent Company As of December 31, 2017 and 2016 , long-term capital leases included $244 million and $278 million , respectively, related to our One Lincoln Street headquarters building and related underground parking garage. Refer to Note 20 for additional information.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments A derivative financial instrument is a financial instrument or other contract which has one or more referenced indices and one or more notional amounts, either no initial net investment or a smaller initial net investment than would be expected for similar types of contracts, and which requires or permits net settlement. We use derivative financial instruments to support our clients' needs and to manage our interest-rate and currency risk. In undertaking these activities, we assume positions in both the foreign exchange and interest-rate markets by buying and selling cash instruments and using derivative financial instruments, including foreign exchange forward contracts, foreign exchange options and interest-rate contracts. Our derivative positions include derivative contracts held by a consolidated sponsored investment fund (refer to Note 14 ). We record derivatives in our consolidated statement of condition at their fair value on a recurring basis. Interest rate contracts involve an agreement with a counterparty to exchange cash flows based on the movement of an underlying interest rate index. An interest rate swap agreement involves the exchange of a series of interest payments, at either a fixed or variable rate, based on the notional amount without the exchange of the underlying principal amount. An interest rate option contract provides the purchaser, for a premium, the right, but not the obligation, to receive an interest rate based upon a predetermined notional amount during a specified period. An interest rate futures contract is a commitment to buy or sell, at a future date, a financial instrument at a contracted price; it may be settled in cash or through the delivery of the contracted instrument. Foreign exchange contracts involve an agreement to exchange one currency for another currency at an agreed-upon rate and settlement date. Foreign exchange contracts generally consist of foreign exchange forward and spot contracts, option contracts and cross-currency swaps. Future cash requirements, if any, related to foreign exchange contracts are represented by the gross amount of currencies to be exchanged under each contract unless we and the counterparty have agreed to pay or to receive the net contractual settlement amount on the settlement date. Derivative financial instruments involve the management of interest-rate and foreign currency risk, and involve, to varying degrees, market risk and credit and counterparty risk (risk related to repayment). Market risk is defined by U.S. banking regulators as the risk of loss that could result from broad market movements, such as changes in the general level of interest rates, credit spreads, foreign exchange rates or commodity prices. We use a variety of risk management tools and methodologies to measure, monitor and manage the market risk associated with our trading activities, which include our use of derivative financial instruments. One such risk-management measure is VaR. VaR is an estimate of potential loss for a given period within a stated statistical confidence interval. We use a risk measurement system to measure VaR daily. We have adopted standards for measuring VaR, and we maintain regulatory capital for market risk in accordance with currently applicable regulatory market risk requirements. Derivative financial instruments are also subject to credit and counterparty risk, which we manage by performing credit reviews, maintaining individual counterparty limits, entering into netting arrangements and requiring the receipt of collateral. Cash collateral received from and provided to counterparties in connection with derivative financial instruments is recorded in accrued expenses and other liabilities and other assets, respectively, in our consolidated statement of condition. As of December 31, 2017 and 2016 , we had recorded approximately $2.55 billion and $1.99 billion , respectively, of cash collateral received from counterparties and approximately $869 million and $4.39 billion , respectively, of cash collateral provided to counterparties in connection with derivative financial instruments in our consolidated statement of condition. Certain of our derivative assets and liabilities as of December 31, 2017 and 2016 are subject to master netting agreements with our derivative counterparties. Certain of these agreements contain credit risk-related contingent features in which the counterparty has the right to declare us in default and accelerate cash settlement of our net derivative liabilities with the counterparty in the event that our credit rating falls below specified levels. The aggregate fair value of all derivative instruments with credit risk-related contingent features that were in a net liability position as of December 31, 2017 totaled approximately $1.13 billion , against which we provided no underlying collateral. If our credit rating were downgraded below levels specified in the agreements, the maximum additional amount of payments related to termination events that could have been required pursuant to these contingent features, assuming no change in fair value, as of December 31, 2017 was approximately $1.13 billion . Such accelerated settlement would be at fair value and therefore not affect our consolidated results of operations. On the date a derivative contract is entered into, we designate the derivative as: (1) a hedge of the fair value of a recognized fixed-rate asset or liability or of an unrecognized firm commitment (a “fair value” hedge); (2) a hedge of a forecast transaction or of the variability of cash flows to be received or paid related to a recognized variable-rate asset or liability (a “cash flow” hedge); (3) a foreign currency fair value or cash flow hedge (a “foreign currency” hedge); (4) a hedge of a net investment in a non-U.S. operation; or (5) a derivative utilized in either our trading activities or in our asset-and-liability management activities that is not designated as a hedge of an asset or liability. Unrealized gains and losses on foreign exchange and interest-rate contracts are reported at fair value in our consolidated statement of condition as a component of other assets and accrued expenses and other liabilities, respectively, on a gross basis, except where such gains and losses arise from contracts covered by qualifying master netting agreements. Derivatives Not Designated as Hedging Instruments In connection with our trading activities, we use derivative financial instruments in our role as a financial intermediary and as both a manager and servicer of financial assets, in order to accommodate our clients' investment and risk management needs. In addition, we use derivative financial instruments for risk management purposes as economic hedges, which are not formally designated as accounting hedges, in order to contribute to our overall corporate earnings and liquidity. These activities are designed to generate trading services revenue and to manage volatility in our NII. The level of market risk that we assume is a function of our overall objectives and liquidity needs, our clients' requirements and market volatility. With respect to cross-border investing, our clients often enter into foreign exchange forward contracts to convert currency for international investments and to manage the currency risk in their international investment portfolios. As an active participant in the foreign exchange markets, we provide foreign exchange forward contracts and options in support of these client needs, and also act as a dealer in the currency markets. As part of our trading activities, we assume positions in both the foreign exchange and interest-rate markets by buying and selling cash instruments and using derivative financial instruments, including foreign exchange forward contracts, foreign exchange and interest-rate options and interest rate swaps, interest rate forward contracts, and interest rate futures. In the aggregate, we seek to match positions closely with the objective of minimizing related currency and interest-rate risk. We also use foreign currency swap contracts to manage the foreign exchange risk associated with certain foreign currency-denominated liabilities. The foreign exchange swap contracts are entered into for periods generally consistent with foreign currency exposure of the underlying transactions. The entire change in the fair value of the derivatives utilized in our trading activities are recorded in trading services revenue, and the entire change in fair value of derivatives utilized in our asset-and-liability management activities are recorded in processing fees and other revenue. We offer products that provide book-value protection primarily to plan participants in stable value funds managed by non-affiliated investment managers of post-retirement defined contribution benefit plans, particularly 401(k) plans. We account for the associated contingencies, more fully described in Note 12 , individually as derivative financial instruments. These contracts are valued quarterly and unrealized losses, if any, are recorded in other expenses in our consolidated statement of income. We grant deferred cash awards to certain of our employees as part of our employee incentive compensation plans. We account for these awards as derivative financial instruments, as the underlying referenced shares are not equity instruments of State Street. The fair value of these derivatives is referenced to the value of units in State Street-sponsored investment funds or funds sponsored by other unrelated entities. We re-measure these derivatives to fair value quarterly, and record the change in value in compensation and employee benefits expenses in our consolidated statement of income. Derivatives Designated as Hedging Instruments In connection with our asset-and-liability management activities, we use derivative financial instruments to manage our interest rate risk and foreign currency risk. Interest rate risk, defined as the sensitivity of income or financial condition to variations in interest rates, is a significant non-trading market risk to which our assets and liabilities are exposed. We manage our interest rate risk by identifying, quantifying and hedging our exposures, using fixed-rate portfolio securities and a variety of derivative financial instruments, most frequently interest-rate swaps. Interest rate swap agreements alter the interest-rate characteristics of specific balance sheet assets or liabilities. We use foreign exchange forward and swap contracts to hedge foreign exchange exposure to various foreign currencies with respect to certain assets and liabilities. Our hedging relationships are formally designated, and qualify for hedge accounting, as fair value, cash flow or net investment hedges. At both the inception of the hedge and on an ongoing basis, we formally assess and document the effectiveness of a derivative designated in a hedging relationship and the likelihood that the derivative will be an effective hedge in future periods. We discontinue hedge accounting prospectively when we determine that the derivative is no longer highly effective in offsetting changes in fair value or cash flows of the underlying risk being hedged, the derivative expires, terminates or is sold, or management discontinues the hedge designation. Fair Value Hedges Derivatives designated as fair value hedges are utilized to mitigate the risk of changes in the fair values of recognized assets and liabilities. Differences between the gains and losses on the hedging derivative and the gains and losses on the hedged asset or liability attributable to the hedged risk represent hedge ineffectiveness. We use interest rate or foreign exchange contracts in this manner to manage our exposure to changes in the fair value of hedged items caused by changes in interest rates or foreign exchange rates. Changes in the fair value of a derivative that is highly effective, and that is designated and qualifies as a fair value hedge, are recorded in processing fees and other revenue, along with the changes in fair value of the hedged asset or liability attributable to the hedged risk. We have entered into interest rate swap agreements to modify our interest income from certain AFS investment securities from a fixed rate to a floating rate. The hedged AFS investment securities included hedged trusts that had a weighted-average life of approximately 4.6 years as of December 31, 2017 , compared to 4.5 years as of December 31, 2016 . These trusts are hedged with interest rate swap contracts of similar maturity, repricing frequency and fixed-rate coupons. The interest rate swap contracts convert the interest income from a fixed rate to a floating rate indexed to LIBOR, thereby mitigating our exposure to fluctuations in the fair value of the securities attributable to changes in the benchmark interest rate. We have entered into interest rate swap agreements to modify our interest expense on eight senior notes and one subordinated note from fixed rates to floating rates. The senior and subordinated notes are hedged with interest rate swap contracts with notional amounts, maturities and fixed-rate coupon terms that effectively hedge the fixed-rate notes. The interest rate swap contracts convert the fixed-rate coupons to floating rates indexed to LIBOR, thereby mitigating our exposure to fluctuations in the fair values of the senior and subordinated notes stemming from changes in the benchmark interest rates. The table below summarizes the maturities and the paid fixed interest rates for the hedged senior and subordinated notes: December 31, 2017 Maturity Paid Fixed Interest Rate Senior Notes 2020 2.55% 2021 4.38 2021 1.95 2022 2.65 2023 3.70 2024 3.30 2025 3.55 2026 2.65 Subordinated Notes 2023 3.10 We have entered into foreign exchange swap contracts to hedge the change in fair value attributable to foreign exchange movements in our foreign currency denominated investment securities and deposits. These forward contracts convert the foreign currency risk to U.S. dollars, thereby mitigating our exposure to fluctuations in the fair value of the securities and deposits attributable to changes in foreign exchange rates. Generally, no ineffectiveness is recorded in earnings, since the notional amount of the hedging instruments is aligned with the carrying value of the hedged securities and deposits. The forward points on the hedging instruments are considered to be a hedging cost, and accordingly are excluded from the evaluation of hedge effectiveness and recorded in NII. Changes in the fair value of a derivative that are highly effective, and that are designated and qualify as a foreign currency hedge, are recorded in processing fees and other revenue. Cash Flow Hedges Derivatives categorized as cash flow hedges are utilized to offset the variability of cash flows to be received from or paid on a floating-rate asset or liability. Ineffectiveness of cash flow hedges is defined as the extent to which the changes in fair value of the derivative exceed the changes in the present value of the forecasted cash flows attributable to the forecasted transaction. We have entered into foreign exchange contracts to hedge the change in cash flows attributable to foreign exchange movements in foreign currency denominated investment securities. These foreign exchange contracts convert the foreign currency risk to U.S. dollars, thereby mitigating our exposure to fluctuations in the cash flows of the securities attributable to changes in foreign exchange rates. Generally, no ineffectiveness is recorded in earnings, since the critical terms of the hedging instruments and the hedged securities are aligned. Changes in the fair value of the derivative that are highly effective, and that are designated and qualify as a foreign currency hedge, are recorded in other comprehensive income. We have entered into an interest rate swap agreement to hedge the forecasted cash flows associated with LIBOR-indexed floating-rate loans. The interest rate swaps synthetically convert the loan interest receipts from a variable-rate to a fixed-rate, thereby mitigating the risk attributable to changes in the LIBOR benchmark rate. As of December 31, 2017 , the maximum maturity date of the underlying loans is approximately 4.9 years . Net Investment Hedges We have entered into foreign exchange contracts to protect the net investment in our foreign operations against adverse changes in exchange rates. These forward contracts convert the foreign currency risk to U.S. dollars, thereby mitigating our exposure to fluctuations in the fair value of our net investments in our foreign operations attributable to changes in foreign exchange rates. The changes in fair value of the foreign exchange forward contracts are recorded, net of taxes, in the foreign currency translation component of other comprehensive income. Effectiveness of net investment hedges is based on the overall changes in the fair value of the forward contracts and we measure the ineffectiveness of net investment hedge based on changes in forward foreign currency rates. There was no ineffectiveness for our net investment hedge during 2017. The following table presents the aggregate contractual, or notional, amounts of derivative financial instruments entered into in connection with our trading and asset-and-liability management activities as of the dates indicated: (In millions) December 31, December 31, Derivatives not designated as hedging instruments: Interest-rate contracts: Futures 2,392 13,455 Foreign exchange contracts: Forward, swap and spot 1,679,976 1,414,765 Options purchased 350 337 Options written 302 202 Futures 50 — Commodity and equity contracts: Commodity (1) 16 — Equity (1) 50 — Other: Stable value contracts 26,653 27,182 Deferred value awards (2)(3) 473 409 Derivatives designated as hedging instruments: Interest-rate contracts: Swap agreements 11,047 10,169 Foreign exchange contracts: Forward and swap 28,913 8,564 (1) Primarily composed of positions held by a consolidated sponsored investment fund, more fully described in Note 14 . (2) Represents grants of deferred value awards to employees; refer to discussion in this note under "Derivatives Not Designated as Hedging Instruments." (3) Amount as of December 31, 2016 reflects $249 million related to the acceleration of expense associated with certain cash settled deferred incentive compensation awards. In connection with our asset-and-liability management activities, we have entered into interest-rate contracts designated as fair value and cash flow hedges to manage our interest rate risk. The following tables present the aggregate notional amounts of these interest rate contracts and the related assets or liabilities being hedged as of the dates indicated: December 31, 2017 (In millions) Fair Value Hedges Cash (1) Total Investment securities available for sale $ 1,254 $ — $ 1,254 Long-term debt (2) 8,493 — 8,493 Floating rate loans — 1,300 1,300 Total $ 9,747 $ 1,300 $ 11,047 December 31, 2016 (In millions) Fair Value Hedges Cash Total Investment securities available for sale $ 1,444 $ — $ 1,444 Long-term debt (2) 8,725 — 8,725 Floating rate loans — — — Total $ 10,169 $ — $ 10,169 (1) In 2017 , we entered into interest-rate contracts designated as cash flow hedges for floating rate loans. (2) As of December 31, 2017 and December 31, 2016 , these fair value hedges decreased the carrying value of long-term debt presented in our consolidated statement of condition by $87 million and $15 million , respectively. Notional amounts of derivative financial instruments are not recorded in the consolidated statement of condition. They are provided here as an indication of the volume of our derivative activity and do not represent a measure of our potential gains or losses. The notional amounts are not required to be exchanged for most of our derivative contracts and they generally serve as a reference to calculate the fair values of the derivatives. The following table presents the contractual and weighted-average interest rates for long-term debt, which include the effects of the fair value hedges presented in the table above, for the periods indicated: Years Ended December 31, 2017 2016 Contractual Rate Contractual Rate Long-term debt 3.34 % 2.66 % 3.40 % 2.29 % The following tables present the fair value of derivative financial instruments, excluding the impact of master netting agreements, recorded in our consolidated statement of condition as of the dates indicated. The impact of master netting agreements is provided in Note 11 to the consolidated financial statements in this Form 10-K. Derivative Assets (1) Fair Value (In millions) December 31, 2017 December 31, 2016 Derivatives not designated as hedging instruments: Foreign exchange contracts $ 11,477 $ 15,982 Other derivative contracts 1 — Total $ 11,478 $ 15,982 Derivatives designated as hedging instruments: Foreign exchange contracts $ 120 $ 502 Interest-rate contracts 8 68 Total $ 128 $ 570 (1) Derivative assets are included within other assets in our consolidated statement of condition. Derivative Liabilities (1) Fair Value (In millions) December 31, 2017 December 31, 2016 Derivatives not designated as hedging instruments: Foreign exchange contracts $ 11,361 $ 15,881 Other derivative contracts 284 380 Total $ 11,645 $ 16,261 Derivatives designated as hedging instruments: Foreign exchange contracts $ 107 $ 75 Interest-rate contracts 100 348 Total $ 207 $ 423 (1) Derivative liabilities are included within other liabilities in our consolidated statement of condition. The following tables present the impact of our use of derivative financial instruments on our consolidated statement of income for the periods indicated: Location of Gain (Loss) on Derivative in Consolidated Statement of Income Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Years Ended December 31, (In millions) 2017 2016 2015 Derivatives not designated as hedging instruments: Foreign exchange contracts Trading services revenue $ 632 $ 662 $ 686 Interest-rate contracts Processing fees and other revenue — 1 — Foreign exchange contracts Processing fees and other revenue (23 ) — — Interest-rate contracts Trading services revenue 8 (7 ) (2 ) Credit derivative contracts Trading services revenue — (1 ) (1 ) Other derivative contracts Trading services revenue — (2 ) 8 Other derivative contracts Compensation and employee benefits (143 ) (448 ) (149 ) Total $ 474 $ 205 $ 542 Location of Gain (Loss) on Derivative in Consolidated Statement of Income Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Hedged Item in Fair Value Hedging Relationship Location of Gain (Loss) on Hedged Item in Consolidated Statement of Income Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income Years Ended December 31, Years Ended December 31, (In millions) 2017 2016 2015 2017 2016 2015 Derivatives designated as fair value hedges: Foreign exchange contracts Processing fees and $ 18 $ (6 ) $ (101 ) Investment securities Processing fees and $ (18 ) $ 6 $ 101 Foreign exchange contracts Processing fees and other revenue 626 221 (241 ) FX deposit Processing fees and other revenue (626 ) (221 ) 241 Interest-rate contracts Processing fees and other revenue 39 43 16 Available-for-sale securities Processing fees and other revenue (1) (37 ) (40 ) (17 ) Interest-rate contracts Processing fees and (38 ) (98 ) 61 Long-term debt Processing fees and 39 100 (54 ) Total $ 645 $ 160 $ (265 ) $ (642 ) $ (155 ) $ 271 (1) In 2017 , 2016 and 2015 , $22 million , $23 million and $12 million , respectively, of net unrealized gains on AFS investment securities designated in fair value hedges were recognized in OCI. Differences between the gains (losses) on the derivative and the gains (losses) on the hedged item, excluding any amounts recorded in NII, represent hedge ineffectiveness. Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income Location of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income Location of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Years Ended December 31, Years Ended December 31, Years Ended December 31, (In millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Derivatives designated as cash flow hedges: Interest-rate contracts $ (14 ) $ — $ — Net interest income $ — $ — $ (4 ) Net interest income $ 2 $ — $ — Foreign exchange contracts (104 ) (39 ) 55 Net interest income — — — Net interest income 24 24 10 Total $ (118 ) $ (39 ) $ 55 $ — $ — $ (4 ) $ 26 $ 24 $ 10 Derivatives designated as net investment hedges: Foreign exchange contracts $ (160 ) $ 109 $ — Gains (Losses) related to investment securities, net $ — $ — $ — Gains (Losses) related to investment securities, net $ — $ — $ — Total $ (160 ) $ 109 $ — $ — $ — $ — $ — $ — $ —

Offsetting Arrangements

Offsetting Arrangements	12 Months Ended
	Dec. 31, 2017
Offsetting [Abstract]
Offsetting Arrangements	Offsetting Arrangements We manage credit and counterparty risk by entering into enforceable netting agreements and other collateral arrangements with counterparties to derivative contracts and secured financing transactions, including resale and repurchase agreements, and principal securities borrowing and lending agreements. These netting agreements mitigate our counterparty credit risk by providing for a single net settlement with a counterparty of all financial transactions covered by the agreement in an event of default as defined under such agreement. In limited cases, a netting agreement may also provide for the periodic netting of settlement payments with respect to multiple different transaction types in the normal course of business. Certain of our derivative contracts are executed under either standardized netting agreements or, for exchange-traded derivatives, the relevant contracts for a particular exchange which contain enforceable netting provisions. In certain cases, we may have cross-product netting arrangements which allow for netting and set-off of a variety of types of derivatives with a single counterparty. A derivative netting arrangement creates an enforceable right of set-off that becomes effective, and effects the realization or settlement of individual financial assets and liabilities, only following a specified event of default. Collateral requirements associated with our derivative contracts are determined after a review of the creditworthiness of each counterparty, and the requirements are monitored and adjusted daily, typically based on net exposure by counterparty. Collateral is generally in the form of cash or highly liquid U.S. government securities. In connection with secured financing transactions, we enter into netting agreements and other collateral arrangements with counterparties, which provide for the right to liquidate collateral in the event of default. Collateral is generally required in the form of cash, equity securities or fixed-income securities. Default events may include the failure to make payments or deliver securities timely, material adverse changes in financial condition or insolvency, the breach of minimum regulatory capital requirements, or loss of license, charter or other legal authorization necessary to perform under the contract. In order for an arrangement to be eligible for netting, we must have a reasonable basis to conclude that such netting arrangements are legally enforceable. The analysis of the legal enforceability of an arrangement differs by jurisdiction, depending on the laws of that jurisdiction. In many jurisdictions, specific legislation exists that provides for the enforceability in bankruptcy of close-out netting under a netting agreement, typically by way of specific exception from more general prohibitions on the exercise of creditor rights. When we have a legally enforceable netting arrangement between us and the derivative counterparty and the relevant transaction is the type of transaction that is recorded in our consolidated statement of condition, we offset derivative assets and liabilities, and the related collateral received and provided, in our consolidated statement of condition. We also offset assets and liabilities related to secured financing transactions with the same counterparty or clearinghouse which have the same maturity date and are settled in the normal course of business on a net basis. Collateral that we receive in the form of securities in connection with secured financing transactions and derivative contracts can be transferred or re-pledged as collateral in many instances to enter into repurchase agreements or securities finance or derivative transactions. The securities collateral received in connection with our securities finance activities is recorded at fair value in other assets in our consolidated statement of condition, with a related liability to return the collateral, if we have the right to transfer or re-pledge the collateral. As of December 31, 2017 and December 31, 2016 , the fair value of securities received as collateral from third parties where we are permitted to transfer or re-pledge the securities totaled $2.47 billion and $1.77 billion , respectively, and the fair value of the portion that had been transferred or re-pledged as of the same dates was $15 million and $166 million , respectively. The following tables present information about the offsetting of assets related to derivative contracts and secured financing transactions, as of the dates indicated: Assets: December 31, 2017 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Assets (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Assets Presented in Statement of Condition Cash and Securities Received (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 11,597 $ (5,548 ) $ 6,049 $ 6,049 Interest-rate contracts (6) 8 — 8 8 Other derivative contracts 1 — 1 1 Cash collateral and securities netting NA (2,045 ) (2,045 ) $ (124 ) (2,169 ) Total derivatives 11,606 (7,593 ) 4,013 (124 ) 3,889 Other financial instruments: Resale agreements and securities borrowing (7) 70,079 (47,434 ) 22,645 (22,645 ) — Total derivatives and other financial instruments $ 81,685 $ (55,027 ) $ 26,658 $ (22,769 ) $ 3,889 Assets: December 31, 2016 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Assets (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Assets Presented in Statement of Condition Cash and Securities Received (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 16,484 $ (8,257 ) $ 8,227 $ 8,227 Interest-rate contracts 68 (68 ) — — Cash collateral and securities netting NA (906 ) (906 ) $ (247 ) (1,153 ) Total derivatives 16,552 (9,231 ) 7,321 (247 ) 7,074 Other financial instruments: Resale agreements and securities borrowing (7) 58,677 (35,517 ) 23,160 (22,939 ) 221 Total derivatives and other financial instruments $ 75,229 $ (44,748 ) $ 30,481 $ (23,186 ) $ 7,295 (1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement. (2) Derivative amounts are carried at fair value and securities financing amounts are carried at amortized cost, except for securities collateral which is also carried at fair value. Refer to Note 1 and Note 2 for additional information about the measurement basis of these instruments. (3) Amounts subject to netting arrangements which have been determined to be legally enforceable and eligible for netting in the consolidated statement of condition. (4) Includes securities in connection with our securities borrowing transactions. (5) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements. (6) Variation margin payments presented as settlements rather than collateral. (7) Included in the $22,645 million as of December 31, 2017 were $3,241 million of resale agreements and $19,404 million of collateral provided related to securities borrowing. Included in the $23,160 million as of December 31, 2016 were $1,956 million of resale agreements and $21,204 million of collateral provided related to securities borrowing. Resale agreements and collateral provided related to securities borrowing were recorded in securities purchased under resale agreements and other assets, respectively, in our consolidated statement of condition. Refer to Note 12 for additional information with respect to principal securities finance transactions. NA Not applicable The following tables present information about the offsetting of liabilities related to derivative contracts and secured financing transactions, as of the dates indicated: Liabilities: December 31, 2017 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Liabilities (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Liabilities Presented in Statement of Condition Cash and Securities Provided (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 11,467 $ (5,548 ) $ 5,919 $ 5,919 Interest-rate contracts (6) 100 — 100 100 Other derivative contracts 285 — 285 285 Cash collateral and securities netting NA (422 ) (422 ) $ (450 ) (872 ) Total derivatives 11,852 (5,970 ) 5,882 (450 ) 5,432 Other financial instruments: Repurchase agreements and securities lending (7) 54,127 (47,434 ) 6,693 (4,299 ) 2,394 Total derivatives and other financial instruments $ 65,979 $ (53,404 ) $ 12,575 $ (4,749 ) $ 7,826 Liabilities: December 31, 2016 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Liabilities (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Liabilities Presented in Statement of Condition Cash and Securities Provided (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 15,956 $ (8,253 ) $ 7,703 $ 7,703 Interest-rate contracts 348 (73 ) 275 275 Other derivative contracts 380 — 380 380 Cash collateral and securities netting NA (2,356 ) (2,356 ) $ (180 ) (2,536 ) Total derivatives 16,684 (10,682 ) 6,002 (180 ) 5,822 Other financial instruments: Resale agreements and securities lending (7) 44,933 (35,517 ) 9,416 (7,059 ) 2,357 Total derivatives and other financial instruments $ 61,617 $ (46,199 ) $ 15,418 $ (7,239 ) $ 8,179 (1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement. (2) Derivative amounts are carried at fair value and securities financing amounts are carried at amortized cost, except for securities collateral which is also carried at fair value. Refer to Note 1 and Note 2 for additional information about the measurement basis of these instruments. (3) Amounts subject to netting arrangements which have been determined to be legally enforceable and eligible for netting in the consolidated statement of condition. (4) Includes securities provided in connection with our securities lending transactions. (5) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements. (6) Variation margin payments presented as settlements rather than collateral. (7) Included in the $6,693 million as of December 31, 2017 were $2,842 million of repurchase agreements and $3,851 million of collateral received related to securities lending. Included in the $9,416 million as of December 31, 2016 were $4,400 million of repurchase agreements and $5,016 million of collateral received related to securities lending. Repurchase agreements and collateral received related to securities lending were recorded in securities sold under repurchase agreements and accrued expenses and other liabilit ies, respectively, in our consolidated statement of condition. Refer to Note 12 for additional information with respect to principal securities finance transactions . NA Not applicable The securities transferred under resale and repurchase agreements typically are U.S. Treasury, agency and agency MBS. In our principal securities borrowing and lending arrangements, the securities transferred are predominantly equity securities and some corporate debt securities. The fair value of the securities transferred may increase in value to an amount greater than the amount received under our repurchase and securities lending arrangements, which exposes the Company with counterparty risk. We require the review of the price of the underlying securities in relation to the carrying value of the repurchase agreements and securities lending arrangements on a daily basis and when appropriate, adjust the cash or security to be obtained or returned to counterparties that is reflective of the required collateral levels. The following tables summarize our repurchase agreements and securities lending transactions by category of collateral pledged and remaining maturity of these agreements as of the periods indicated: Remaining Contractual Maturity of the Agreements As of December 31, 2017 (In millions) Overnight and Continuous Up to 30 days 30 – 90 days Total Repurchase agreements: U.S. Treasury and agency securities $ 43,072 $ — $ — $ 43,072 Total 43,072 — — 43,072 Securities lending transactions: Corporate debt securities 35 — — 35 Equity securities 11,020 — — 11,020 Non-U.S. sovereign debt — — — — Total 11,055 — — 11,055 Gross amount of recognized liabilities for repurchase agreements and securities lending $ 54,127 $ — $ — $ 54,127 Remaining Contractual Maturity of the Agreements As of December 31, 2016 (In millions) Overnight and Continuous Up to 30 days 30 – 90 days Total Repurchase agreements: U.S. Treasury and agency securities $ 35,509 $ — $ — $ 35,509 Total 35,509 — — 35,509 Securities lending transactions: Corporate debt securities 53 — — 53 Equity securities 8,337 — 1,034 9,371 Total 8,390 — 1,034 9,424 Gross amount of recognized liabilities for repurchase agreements and securities lending $ 43,899 $ — $ 1,034 $ 44,933

Commitments and Guarantees

Commitments and Guarantees	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Guarantees	Commitments and Guarantees The following table presents the aggregate gross contractual amounts of our off-balance sheet commitments and off-balance sheet guarantees as of the dates indicated. (In millions) December 31, 2017 December 31, 2016 Commitments: Unfunded credit facilities $ 26,488 $ 26,993 Guarantees (1) : Indemnified securities financing $ 381,817 $ 360,452 Stable value protection 26,653 27,182 Standby letters of credit 3,158 3,459 (1) The potential losses associated with these guarantees equal the gross contractual amounts and do not consider the value of any collateral or reflect any participations to independent third parties. Unfunded Credit Facilities Unfunded credit facilities consist of liquidity facilities for our fund and municipal lending clients and undrawn lines of credit related to senior secured bank loans. As of December 31, 2017 , approximately 72% of our unfunded commitments to extend credit expire within one year. Since many of these commitments are expected to expire or renew without being drawn upon, the gross contractual amounts do not necessarily represent our future cash requirements. Indemnified Securities Financing On behalf of our clients, we lend their securities, as agent, to brokers and other institutions. In most circumstances, we indemnify our clients for the fair market value of those securities against a failure of the borrower to return such securities. We require the borrowers to maintain collateral in an amount in excess of 100% of the fair market value of the securities borrowed. Securities on loan and the collateral are revalued daily to determine if additional collateral is necessary or if excess collateral is required to be returned to the borrower. Collateral received in connection with our securities lending services is held by us as agent and is not recorded in our consolidated statement of condition. The cash collateral held by us as agent is invested on behalf of our clients. In certain cases, the cash collateral is invested in third-party repurchase agreements, for which we indemnify the client against loss of the principal invested. We require the counterparty to the indemnified repurchase agreement to provide collateral in an amount in excess of 100% of the amount of the repurchase agreement. In our role as agent, the indemnified repurchase agreements and the related collateral held by us are not recorded in our consolidated statement of condition. The following table summarizes the aggregate fair values of indemnified securities financing and related collateral, as well as collateral invested in indemnified repurchase agreements, as of the dates indicated: (In millions) December 31, 2017 December 31, 2016 Fair value of indemnified securities financing $ 381,817 $ 360,452 Fair value of cash and securities held by us, as agent, as collateral for indemnified securities financing 400,828 377,919 Fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements 61,270 60,003 Fair value of cash and securities held by us or our agents as collateral for investments in indemnified repurchase agreements 65,272 63,959 In certain cases, we participate in securities finance transactions as a principal. As a principal, we borrow securities from the lending client and then lend such securities to the subsequent borrower, either a State Street client or a broker/dealer. Our right to receive and obligation to return collateral in connection with our securities lending transactions are recorded in other assets and other liabilities, respectively, in our consolidated statement of condition. As of December 31, 2017 and December 31, 2016 , we had approximately $19.40 billion and $21.20 billion , respectively, of collateral provided and approximately $3.85 billion and $5.02 billion , respectively, of collateral received from clients in connection with our participation in principal securities finance transactions. Stable Value Protection In the normal course of our business, we offer products that provide book-value protection, primarily to plan participants in stable value funds managed by non-affiliated investment managers of post-retirement defined contribution benefit plans, particularly 401(k) plans. The book-value protection is provided on portfolios of intermediate investment grade fixed-income securities, and is intended to provide safety and stable growth of principal invested. The protection is intended to cover any shortfall in the event that a significant number of plan participants withdraw funds when book value exceeds market value and the liquidation of the assets is not sufficient to redeem the participants. The investment parameters of the underlying portfolios, combined with structural protections, are designed to provide cushion and guard against payments even under extreme stress scenarios. These contingencies are individually accounted for as derivative financial instruments. The notional amounts of the stable value contracts are presented as “derivatives not designated as hedging instruments” in the table of aggregate notional amounts of derivative financial instruments provided in Note 10 . We have not made a payment under these contingencies that we consider material to our consolidated financial condition, and management believes that the probability of payment under these contingencies in the future, that we would consider material to our consolidated financial condition, is remote. Standby Letters of Credit Standby letters of credit provide credit enhancement to our municipal clients to support the issuance of capital markets financing.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies Legal and Regulatory Matters In the ordinary course of business, we and our subsidiaries are involved in disputes, litigation, and governmental or regulatory inquiries and investigations, both pending and threatened. These matters, if resolved adversely against us or settled, may result in monetary damages, fines and penalties or require changes in our business practices. The resolution or settlement of these matters is inherently difficult to predict. Based on our assessment of these pending matters, we do not believe that the amount of any judgment, settlement or other action arising from any pending matter is likely to have a material adverse effect on our consolidated financial condition. However, an adverse outcome in certain of the matters described below could have a material adverse effect on our consolidated results of operations for the period in which such matter is resolved, or an accrual is determined to be required, on our consolidated financial condition, or on our reputation. We evaluate our needs for accruals of loss contingencies related to legal and regulatory proceedings on a case-by-case basis. When we have a liability that we deem probable, and we deem the amount of such liability can be reasonably estimated as of the date of our consolidated financial statements, we accrue our estimate of the amount of loss. We also consider a loss probable and establish an accrual when we make, or intend to make, an offer of settlement. Once established, an accrual is subject to subsequent adjustment as a result of additional information. The resolution of legal and regulatory proceedings and the amount of reasonably estimable loss (or range thereof) are inherently difficult to predict, especially in the early stages of proceedings. Even if a loss is probable, an amount (or range) of loss might not be reasonably estimated until the later stages of the proceeding due to many factors such as the presence of complex or novel legal theories, the discretion of governmental authorities in seeking sanctions or negotiating resolutions in civil and criminal matters, the pace and timing of discovery and other assessments of facts and the procedural posture of the matter (collectively, "factors influencing reasonable estimates"). As of December 31, 2017 , our aggregate accruals for loss contingencies for legal and regulatory matters totaled approximately $12 million . To the extent that we have established accruals in our consolidated statement of condition for probable loss contingencies, such accruals may not be sufficient to cover our ultimate financial exposure associated with any settlements or judgments. Any such ultimate financial exposure, or proceedings to which we may become subject in the future, could have a material adverse effect on our businesses, on our future consolidated financial statements or on our reputation. Except where otherwise noted below, we have not established significant accruals with respect to the claims discussed. We have identified certain matters for which loss is reasonably possible (but not probable) in future periods, whether in excess of an accrued liability or where there is no accrued liability, and for which we are able to estimate a range of reasonably possible loss. As of December 31, 2017 , our estimate of the range of reasonably possible loss for these matters is from zero to approximately $15 million in the aggregate. Our estimate with respect to the aggregate range of reasonably possible loss is based upon currently available information and is subject to significant judgment and a variety of assumptions and known and unknown uncertainties. The matters underlying the estimated range will change from time to time, and actual results may vary significantly from the current estimate. In certain other pending matters, including the invoicing matter, Federal Reserve/Massachusetts Division of Banks written agreement and shareholder litigation matters discussed below, it is not currently feasible to reasonably estimate the amount or a range of reasonably possible loss (including reasonably possible loss in excess of amounts accrued), and such losses, which may be significant, are not included in the estimate of reasonably possible loss discussed above. This is due to, among other factors, the factors influencing reasonable estimates described above. These factors are particularly prevalent in governmental and regulatory inquiries and investigations. As a result, reasonably possible loss estimates often are not feasible until the later stages of the inquiry or investigation or of any related legal or regulatory proceeding. An adverse outcome in one or more of the matters for which we have not estimated the amount or a range of reasonably possible loss, individually or in the aggregate, could have a material adverse effect on our businesses, on our future consolidated financial statements or on our reputation. Given that we cannot estimate reasonably possible loss for all legal and regulatory proceedings as to which we may be subject now or in the future, including matters that if adversely concluded may present material financial, regulatory and reputational risks, no conclusion as to the ultimate exposure from current pending or potential legal or regulatory proceedings should be drawn from the current estimate of reasonably possible loss. The following discussion provides information with respect to significant legal, governmental and regulatory matters. Invoicing Matter In December 2015, we announced a review of the manner in which we invoiced certain expenses to some of our Investment Servicing clients, primarily in the United States, during an 18-year period going back to 1998, and our determination that we had incorrectly invoiced clients for certain expenses. We informed our clients in December 2015 that we will pay to them the amounts we concluded were incorrectly invoiced to them, plus interest. We are implementing enhancements to our billing processes, and we are reviewing the conduct of our employees and have taken appropriate steps to address conduct inconsistent with our standards, including, in some cases, termination of employment. In connection with our enhancements to our billing processes, we continue to review historical billing practices and may from time to time identify additional remediation. We currently expect the cumulative total of our payments to customers for these matters to be at least $360 million . We have received a purported class action demand letter alleging that our invoicing practices were unfair and deceptive under Massachusetts law. A class of customers, or particular customers, may assert that we have not paid to them all amounts incorrectly invoiced, and may seek double or treble damages under Massachusetts law. In addition, in March 2017, a purported class action was commenced against us alleging that our invoicing practices violated duties owed to retirement plan customers under ERISA. We are also responding to requests for information from, and are cooperating with investigations by, governmental and regulatory authorities on these matters, including the civil and criminal divisions of the DOJ, the SEC, the DOL, the Massachusetts Attorney General, and the New Hampshire Bureau of Securities Regulation, which could result in significant fines or other sanctions, civil and criminal, against us. If these governmental or regulatory authorities were to conclude that all or a portion of the billing errors merited civil or criminal sanctions, any fine or other penalty could be a significant percentage, or a multiple of, the portion of the overcharging serving as the basis of such a claim or of the full amount overcharged. The governmental and regulatory authorities have significant discretion in civil and criminal matters as to the fines and other penalties they may seek to impose. The severity of such fines or other penalties could take into account factors such as the amount and duration of our incorrect invoicing, the government’s or regulator's assessment of the conduct of our employees, as well as prior conduct such as that which resulted in our January 2017 deferred prosecution agreement in connection with transition management services and our recent settlement of civil claims regarding our indirect foreign exchange business. The outcome of any of these proceedings and, in particular, any criminal sanction could materially adversely affect our results of operations and could have significant collateral consequences for our business and reputation. Federal Reserve/Massachusetts Division of Banks Written Agreement On June 1, 2015, we entered into a written agreement with the Federal Reserve and the Massachusetts Division of Banks relating to deficiencies identified in our compliance programs with the requirements of the Bank Secrecy Act, AML regulations and U.S. economic sanctions regulations promulgated by OFAC. As part of this enforcement action, we have been required to, among other things, implement improvements to our compliance programs and to retain an independent firm to conduct a review of account and transaction activity to evaluate whether any suspicious activity was not previously reported. If we fail to comply with the terms of the written agreement, we may become subject to fines and other regulatory sanctions, which may have a material adverse effect on us. Shareholder Litigation A State Street shareholder has filed a purported class action complaint against the Company alleging that the Company’s financial statements in its annual reports for the 2011-2014 period were misleading due to the inclusion of revenues associated with the invoicing matter referenced above and the facts surrounding our 2017 settlements with the U.S. government relating to our transition management business. In addition, a State Street shareholder has filed a derivative complaint against the Company's past and present officers and directors to recover alleged losses incurred by the Company relating to the invoicing matter and to our Ohio public retirement plans matter. Income Taxes In determining our provision for income taxes, we make certain judgments and interpretations with respect to tax laws in jurisdictions in which we have business operations. Because of the complex nature of these laws, in the normal course of our business, we are subject to challenges from U.S. and non-U.S. income tax authorities regarding the amount of income taxes due. These challenges may result in adjustments to the timing or amount of taxable income or deductions or the allocation of taxable income among tax jurisdictions. We recognize a tax benefit when it is more likely than not that our position will result in a tax deduction or credit. Additional information with respect to our provision for income taxes and tax benefits, including unrecognized tax benefits, is provided in Note 22 . We are presently under audit by a number of tax authorities, and the Internal Revenue Service is currently reviewing our U.S. income tax returns for the tax years 2014 and 2015. The earliest tax year open to examination in jurisdictions where we have material operations is 2011. Management believes that we have sufficiently accrued liabilities as of December 31, 2017 for tax exposures.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities We are involved, in the normal course of our business, with various types of special purpose entities, some of which meet the definition of VIEs. When evaluating a VIE for consolidation, we must determine whether or not we have a variable interest in the entity. Variable interests are investments or other interests that absorb portions of an entity’s expected losses or receive portions of the entity’s expected returns. If it is determined that State Street does not have a variable interest in the VIE, no further analysis is required and State Street does not consolidate the VIE. If State Street holds a variable interest in a VIE, we are required by U.S. GAAP to consolidate that VIE when we have a controlling financial interest in the VIE and therefore are deemed to be the primary beneficiary. State Street is determined to have a controlling financial interest in a VIE when it has both the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to that VIE. This determination is evaluated periodically as facts and circumstances change. Asset-Backed Investment Securities We invest in various forms of ABS, which we carry in our investment securities portfolio. These ABS meet the U.S. GAAP definition of asset securitization entities, which are considered to be VIEs. We are not considered to be the primary beneficiary of these VIEs since we do not have control over their activities. Additional information about our ABS is provided in Note 3 . Tax-Exempt Investment Program In the normal course of our business, we structure and sell certificated interests in pools of tax-exempt investment-grade assets, principally to our mutual fund clients. We structure these pools as partnership trusts, and the assets and liabilities of the trusts are recorded in our consolidated statement of condition as AFS investment securities and other short-term borrowings. As of December 31, 2017 and December 31, 2016 , we carried AFS investment securities, composed of securities related to state and political subdivisions, with a fair value of $1.25 billion and $1.35 billion , respectively, and other short-term borrowings of $1.08 billion and $1.16 billion , respectively, in our consolidated statement of condition in connection with these trusts. The interest income and interest expense generated by the investments and certificated interests, respectively, are recorded as components of NII when earned or incurred. We transfer assets to the trusts from our investment securities portfolio at adjusted book value, and the trusts finance the acquisition of these assets by selling certificated interests issued by the trust to third-party investors and to State Street as residual holder. These transfers do not meet the de-recognition criteria defined by U.S. GAAP, and therefore, the assets continue to be recorded in our consolidated financial statements. The trusts had a weighted-average life of approximately 4.6 years as of December 31, 2017 , compared to approximately 4.5 years as of December 31, 2016 . Under separate legal agreements, we provide liquidity facilities to these trusts and, with respect to certain securities, letters of credit. As of December 31, 2017 , our commitments to the trusts under these liquidity facilities and letters of credit totaled $1.10 billion and $351 million , respectively, and none of the liquidity facilities or letters of credit, were utilized. In the event that our obligations under these liquidity facilities are triggered, no material impact to our consolidated results of operations or financial condition is expected to occur, because the securities are already recorded at fair value in our consolidated statement of condition. In addition, neither creditors or third-party investors in the trusts have any recourse to State Street's general credit other than through the liquidity facilities and letters of credit noted above. Interests in Investment Funds In the normal course of business, we manage various types of investment funds through SSGA in which our clients are investors, including SSGA commingled investment vehicles and other similar investment structures. The majority of our AUM are contained within such funds. The services we provide to these funds generate management fee revenue. From time to time, we may invest cash in the funds in order for the funds to establish a performance history for newly-launched strategies, referred to as seed capital, or for other purposes. With respect to our interests in funds that meet the definition of a VIE, a primary beneficiary assessment is performed to determine if we have a controlling financial interest. As part of our assessment, we consider all the facts and circumstances regarding the terms and characteristics of the variable interest(s), the design and characteristics of the fund and the other involvements of the enterprise with the fund. Upon consolidation of certain funds, we retain the specialized investment company accounting rules followed by the underlying funds. All of the underlying investments held by such consolidated funds are carried at fair value, with corresponding changes in the investments’ fair values reflected in trading services revenue in our consolidated statement of income. When we no longer control these funds due to a reduced ownership interest or other reasons, the funds are de-consolidated and accounted for under another accounting method if we continue to maintain investments in the funds. As of December 31, 2017 , the aggregate assets and liabilities of our consolidated sponsored investment funds totaled $149 million and $50 million , respectively. As of December 31, 2016 , we had no consolidated funds. As of December 31, 2017 , our potential maximum total exposure associated with the consolidated sponsored investment funds totaled $100 million and represented the value of our economic ownership interest in the funds. Our conclusion to consolidate a fund may vary from period to period, most commonly as a result of fluctuation in our ownership interest as a result of changes in the number of fund shares held by either us or by third parties. Given that the funds follow specialized investment company accounting rules which prescribe fair value, a de-consolidation generally would not result in gains or losses for us. The net assets of any consolidated fund are solely available to settle the liabilities of the fund and to settle any investors’ ownership redemption requests, including any seed capital invested in the fund by State Street. We are not contractually required to provide financial or any other support to any of our funds. In addition, neither creditors nor equity investors in the funds have any recourse to State Street’s general credit. As of December 31, 2017 and December 31, 2016 , we managed certain funds, considered VIEs, in which we held a variable interest but for which we were not deemed to be the primary beneficiary. Our potential maximum loss exposure related to these unconsolidated funds totaled $72 million and $121 million as of December 31, 2017 and December 31, 2016 , respectively, and represented the carrying value of our investments, which are recorded in either AFS investment securities or other assets in our consolidated statement of condition. The amount of loss we may recognize during any period is limited to the carrying amount of our investments in the unconsolidated funds.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Shareholders' Equity	Shareholders' Equity Preferred Stock The following table summarizes selected terms of each of the series of the preferred stock issued and outstanding as of December 31, 2017 : Issuance Date Depositary Shares Issued Ownership Interest Per Depositary Share Liquidation Preference Per Share Liquidation Preference Per Depositary Share Net Proceeds of Offering (In millions) Redemption Date (1) Preferred Stock (2) : Series C August 2012 20,000,000 1/4,000th $ 100,000 $ 25 $ 488 September 15, 2017 Series D February 2014 30,000,000 1/4,000th 100,000 25 742 March 15, 2024 Series E November 2014 30,000,000 1/4,000th 100,000 25 728 December 15, 2019 Series F May 2015 750,000 1/100th 100,000 1,000 742 September 15, 2020 Series G April 2016 20,000,000 1/4,000th 100,000 25 493 March 15, 2026 (1) On the redemption date, or any dividend declaration date thereafter, the preferred stock and corresponding depositary shares may be redeemed by us, in whole or in part, at the liquidation price per share and liquidation price per depositary share plus any declared and unpaid dividends, without accumulation of any undeclared dividends. (2) The preferred stock and corresponding depositary shares may be redeemed at our option in whole, but not in part, prior to the redemption date upon the occurrence of a regulatory capital treatment event, as defined in the certificate of designation, at a redemption price equal to the liquidation price per share and liquidation price per depositary share plus any declared and unpaid dividends, without accumulation of any undeclared dividends. The following table present the dividends declared for each of the series of preferred stock issued and outstanding for the periods indicated: Years Ended December 31, 2017 2016 Dividends Declared per Share Dividends Declared per Depositary Share Total (In millions) Dividends Declared per Share Dividends Declared per Depositary Share Total (In millions) Preferred Stock: Series C $ 5,250 $ 1.32 $ 26 $ 5,250 $ 1.32 $ 26 Series D 5,900 1.48 44 5,900 1.48 44 Series E 6,000 1.52 45 6,000 1.52 45 Series F 5,250 52.50 40 5,250 52.50 40 Series G 5,352 1.32 27 3,626 0.90 18 Total $ 182 $ 173 In February 2018, we declared dividends on our Series C, D, E, F and G preferred stock of approximately $1,313 , $1,475 , $1,500 , $2,625 and $1,338 , respectively, per share, or approximately $0.33 , $0.37 , $0.38 , $26.25 and $0.33 , respectively, per depositary share. These dividends total approximately $6 million , $11 million , $11 million , $20 million and $7 million on our Series C, D, E, F and G preferred stock, respectively, which will be paid in March 2018. Common Stock In June 2017, our Board approved a common stock purchase program authorizing the purchase of up to $1.4 billion of our common stock through June 30, 2018 (the 2017 Program). In June 2016, our Board approved a common stock purchase program authorizing the purchase of up to $1.4 billion of our common stock through June 30, 2017 (the 2016 Program). The table below presents the activity under both the 2017 Program and 2016 Program during the year ended December 31, 2017: Shares Acquired Average Cost per Share Total Acquired 2016 Program (1) 9.4 $ 79.93 $ 750 2017 Program 7.4 94.54 700 Total 16.8 $ 86.37 $ 1,450 (1) Includes $158 million relating to shares acquired in exchange for BFDS stock during the first quarter of 2017. Additional information about the exchange is provided in Note 1 to the consolidated financial statements included in this Form 10-K. The table below presents the dividends declared on common stock for the periods indicated: Years Ended December 31, 2017 2016 Dividends Declared per Share Total (In millions) Dividends Declared per Share Total (In millions) Common Stock $ 1.60 $ 596 $ 1.44 $ 559 Accumulated Other Comprehensive Income (Loss) The following table presents the after-tax components of AOCI as of the dates indicated: December 31 (In millions) 2017 2016 2015 Net unrealized gains (losses) on cash flow hedges $ (56 ) $ 229 $ 293 Net unrealized gains (losses) on available-for-sale securities portfolio 148 (225 ) 9 Net unrealized gains (losses) related to reclassified available-for-sale securities 19 25 (28 ) Net unrealized gains (losses) on available-for-sale securities 167 (200 ) (19 ) Net unrealized losses on available-for-sale securities designated in fair value hedges (64 ) (86 ) (109 ) Net unrealized gains (losses) on hedges of net investments in non-U.S. subsidiaries (65 ) 95 (14 ) Other-than-temporary impairment on held-to-maturity securities related to factors other than credit (6 ) (9 ) (16 ) Net unrealized losses on retirement plans (170 ) (194 ) (183 ) Foreign currency translation (815 ) (1,875 ) (1,394 ) Total $ (1,009 ) $ (2,040 ) $ (1,442 ) The following table presents changes in AOCI by component, net of related taxes, for the periods indicated: (In millions) Net Unrealized Gains (Losses) on Cash Flow Hedges Net Unrealized Gains (Losses) on Available-for-Sale Securities Net Unrealized Gains (Losses) on Hedges of Net Investments in Non-U.S. Subsidiaries Other-Than-Temporary Impairment on Held-to-Maturity Securities Net Unrealized Losses on Retirement Plans Foreign Currency Translation Total Balance as of December 31, 2015 $ 293 $ (128 ) $ (14 ) $ (16 ) $ (183 ) $ (1,394 ) $ (1,442 ) Other comprehensive income (loss) before reclassifications (64 ) (164 ) 109 8 — (478 ) (589 ) Amounts reclassified into (out of) earnings — 6 — (1 ) (11 ) (3 ) (9 ) Other comprehensive income (loss) (64 ) (158 ) 109 7 (11 ) (481 ) (598 ) Balance as of December 31, 2016 $ 229 $ (286 ) $ 95 $ (9 ) $ (194 ) $ (1,875 ) $ (2,040 ) Other comprehensive income (loss) before reclassifications (285 ) 412 (160 ) 3 — 1,059 1,029 Amounts reclassified into (out of) earnings — (23 ) — — 24 1 2 Other comprehensive income (loss) (285 ) 389 (160 ) 3 24 1,060 1,031 Balance as of December 31, 2017 $ (56 ) $ 103 $ (65 ) $ (6 ) $ (170 ) $ (815 ) $ (1,009 ) The following table presents after-tax reclassifications into earnings for the periods indicated: Years Ended December 31, 2017 2016 (In millions) Amounts Reclassified into (out of) Earnings Affected Line Item in Consolidated Statement of Income Available-for-sale securities: Net realized gains (losses) from sales of available-for-sale securities, net of related taxes of $16 and ($4), respectively $ (23 ) $ 6 Net gains (losses) from sales of available-for-sale securities Held-to-maturity securities: Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes of $0 and $1, respectively — (1 ) Losses reclassified (from) to other comprehensive income Retirement plans: Amortization of actuarial losses, net of related taxes of ($8) and ($1), respectively 24 (11 ) Compensation and employee benefits expenses Foreign currency translation: Sales of non-U.S. entities, net of related taxes of $0 and ($2), respectively 1 (3 ) Processing fees and other revenue Total reclassifications (out of) into AOCI $ 2 $ (9 )

Regulatory Capital

Regulatory Capital	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Regulatory Capital	Regulatory Capital We are subject to various regulatory capital requirements administered by federal banking agencies. Failure to meet minimum regulatory capital requirements can initiate certain mandatory and discretionary actions by regulators that, if undertaken, could have a direct material effect on our consolidated financial condition. Under current regulatory capital adequacy guidelines, we must meet specified capital requirements that involve quantitative measures of our consolidated assets, liabilities and off-balance sheet exposures calculated in conformity with regulatory accounting practices. Our capital components and their classifications are subject to qualitative judgments by regulators about components, risk weightings and other factors. As required by the Dodd-Frank Act, State Street and State Street Bank, as advanced approaches banking organizations, are subject to a permanent "capital floor" in the calculation and assessment of their regulatory capital adequacy by U.S. banking regulators. Beginning on January 1, 2015, we were required to calculate our risk-based capital ratios using both the advanced approaches and the standardized approach. As a result, from January 1, 2015 going forward, our risk-based capital ratios for regulatory assessment purposes are the lower of each ratio calculated under the standardized approach and the advanced approaches. The methods for the calculation of our and State Street Bank's risk-based capital ratios will change as the provisions of the Basel III final rule related to the numerator (capital) and denominator (risk-weighted assets) are phased in, and as we begin calculating our risk-weighted assets using the advanced approaches. These ongoing methodological changes will result in differences in our reported capital ratios from one reporting period to the next that are independent of applicable changes to our capital base, our asset composition, our off-balance sheet exposures or our risk profile. As of December 31, 2017 , State Street and State Street Bank exceeded all regulatory capital adequacy requirements to which they were subject. As of December 31, 2017 , State Street Bank was categorized as “well capitalized” under the applicable regulatory capital adequacy framework, and exceeded all “well capitalized” ratio guidelines to which it was subject. Management believes that no conditions or events have occurred since December 31, 2017 that have changed the capital categorization of State Street Bank. The following table presents the regulatory capital structure, total risk-weighted assets, related regulatory capital ratios and the minimum required regulatory capital ratios for State Street and State Street Bank as of the dates indicated. As a result of changes in the methodologies used to calculate our regulatory capital ratios from period to period as the provisions of the Basel III final rule are phased in, the ratios presented in the table for each period-end are not directly comparable. Refer to the footnotes following the table. State Street State Street Bank (In millions) Basel III Advanced Approaches December 31, 2017 (1) Basel III Standardized Approach December 31, 2017 (2) Basel III Advanced Approaches December 31, 2016 (1) Basel III Standardized Approach December 31, 2016 (2) Basel III Advanced Approaches December 31, 2017 (1) Basel III Standardized Approach December 31, 2017 (2) Basel III Advanced Approaches December 31, 2016 (1) Basel III Standardized Approach December 31, 2016 (2) Common shareholders' equity: Common stock and related surplus $ 10,302 $ 10,302 $ 10,286 $ 10,286 $ 11,612 $ 11,612 $ 11,376 $ 11,376 Retained earnings 18,856 18,856 17,459 17,459 12,312 12,312 12,285 12,285 Accumulated other comprehensive income (loss) (972 ) (972 ) (1,936 ) (1,936 ) (809 ) (809 ) (1,648 ) (1,648 ) Treasury stock, at cost (9,029 ) (9,029 ) (7,682 ) (7,682 ) — — — — Total 19,157 19,157 18,127 18,127 23,115 23,115 22,013 22,013 Regulatory capital adjustments: Goodwill and other intangible assets, net of associated deferred tax liabilities (3) (6,877 ) (6,877 ) (6,348 ) (6,348 ) (6,579 ) (6,579 ) (6,060 ) (6,060 ) Other adjustments (76 ) (76 ) (155 ) (155 ) (5 ) (5 ) (148 ) (148 ) Common equity tier 1 capital 12,204 12,204 11,624 11,624 16,531 16,531 15,805 15,805 Preferred stock 3,196 3,196 3,196 3,196 — — — — Trust preferred capital securities subject to phase-out from tier 1 capital — — — — — — — — Other adjustments (18 ) (18 ) (103 ) (103 ) — — — — Tier 1 capital 15,382 15,382 14,717 14,717 16,531 16,531 15,805 15,805 Qualifying subordinated long-term debt 980 980 1,172 1,172 983 983 1,179 1,179 Trust preferred capital securities phased out of tier 1 capital — — — — — — — — ALLL and other 4 72 19 77 — 72 15 77 Other adjustments 1 1 1 1 — — — — Total capital $ 16,367 $ 16,435 $ 15,909 $ 15,967 $ 17,514 $ 17,586 $ 16,999 $ 17,061 Risk-weighted assets: Credit risk $ 49,976 $ 101,349 $ 50,900 $ 98,125 $ 47,448 $ 98,433 $ 47,383 $ 94,413 Operational risk (4) 45,822 NA 44,579 NA 45,295 NA 44,043 NA Market risk (5) 3,358 1,334 3,822 1,751 3,375 1,334 3,822 1,751 Total risk-weighted assets $ 99,156 $ 102,683 $ 99,301 $ 99,876 $ 96,118 $ 99,767 $ 95,248 $ 96,164 Adjusted quarterly average assets $ 209,328 $ 209,328 $ 226,310 $ 226,310 $ 206,070 $ 206,070 $ 222,584 $ 222,584 Capital Ratios: 2017 Minimum Requirements Including Capital Conservation Buffer and G-SIB Surcharge (6) 2016 Minimum Requirements Including Capital Conservation Buffer and G-SIB Surcharge (7) Common equity tier 1 capital 6.5 % 5.5 % 12.3 % 11.9 % 11.7 % 11.6 % 17.2 % 16.6 % 16.6 % 16.4 % Tier 1 capital 8.0 7.0 15.5 15.0 14.8 14.7 17.2 16.6 16.6 16.4 Total capital 10.0 9.0 16.5 16.0 16.0 16.0 18.2 17.6 17.8 17.7 Tier 1 leverage 4.0 4.0 7.3 7.3 6.5 6.5 8.0 8.0 7.1 7.1 (1) CET1 capital, tier 1 capital and total capital ratios as of December 31, 2017 and December 31, 2016 were calculated in conformity with the advanced approaches provisions of the Basel III final rule. Tier 1 leverage ratio as of December 31, 2017 and December 31, 2016 were calculated in conformity with the Basel III final rule. (2) CET1 capital, tier 1 capital and total capital ratios as of December 31, 2017 and December 31, 2016 were calculated in conformity with the standardized approach provisions of the Basel III final rule. Tier 1 leverage ratio as of December 31, 2017 and December 31, 2016 were calculated in conformity with the Basel III final rule. (3) Amounts for State Street and State Street Bank as of December 31, 2017 consisted of goodwill, net of associated deferred tax liabilities, and 80% of other intangible assets, net of associated deferred tax liabilities. Amounts for State Street and State Street Bank as of December 31, 2016 consisted of goodwill, net of deferred tax liabilities and 60% of other intangible assets, net of associated deferred tax liabilities. Intangible assets, net of associated deferred tax liabilities is phased in as a deduction from capital, in conformity with the Basel III final rule. (4) Under the current advanced approaches rules and regulatory guidance concerning operational risk models, RWA attributable to operational risk can vary substantially from period-to-period, without direct correlation to the effects of a particular loss event on our results of operations and financial condition and impacting dates and periods that may differ from the dates and periods as of and during which the loss event is reflected in our financial statements, with the timing and categorization dependent on the processes for model updates and, if applicable, model revalidation and regulatory review and related supervisory processes. An individual loss event can have a significant effect on the output of our operational risk RWA under the advanced approaches depending on the severity of the loss event and its categorization among the seven Basel-defined UOMs. (5) Market risk risk-weighted assets reported in conformity with the Basel III advanced approaches included a CVA which reflected the risk of potential fair value adjustments for credit risk reflected in our valuation of over-the-counter derivative contracts. The CVA was not provided for in the final market risk capital rule; however, it was required by the advanced approaches provisions of the Basel III final rule. We used a simple CVA approach in conformity with the Basel III advanced approaches. (6) Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of December 31, 2017 . (7) Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of December 31, 2016 . NA Not applicable

Net Interest Income

Net Interest Income	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Net Interest Income	Net Interest Income The following table presents the components of interest income and interest expense, and related NII, for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Interest income: Deposits with banks $ 180 $ 126 $ 208 Investment securities: U.S. Treasury and federal agencies 854 821 735 State and political subdivisions 226 224 227 Other investments 658 756 934 Securities purchased under resale agreements 264 146 62 Loans and leases 504 378 311 Other interest-earning assets 222 61 11 Total interest income 2,908 2,512 2,488 Interest expense: Deposits 163 85 97 Securities sold under repurchase agreements 2 1 — Short-term borrowings 10 7 7 Long-term debt 308 260 250 Other interest-bearing liabilities 121 75 46 Total interest expense 604 428 400 Net interest income $ 2,304 $ 2,084 $ 2,088

Equity-Based Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity-Based Compensation	Equity-Based Compensation We record compensation expense for equity-based awards, such as restricted stock, deferred stock and performance awards, based on the closing price of our common stock on the date of grant, adjusted if appropriate based on the award’s eligibility to receive dividends. The fair value of stock appreciation rights are determined using the Black-Scholes valuation model. Compensation expense related to equity-based awards with service-only conditions and terms that provide for a graded vesting schedule is recognized on a straight-line basis over the required service period for the entire award. Compensation expense related to equity-based awards with performance conditions and terms that provide for a graded vesting schedule is recognized over the requisite service period for each separately vesting tranche of the award, and is based on the probable outcome of the performance conditions at each reporting date. Compensation expense is adjusted for assumptions with respect to the estimated amount of awards that will be forfeited prior to vesting, and for employees who have met certain retirement eligibility criteria. Compensation expense for common stock awards granted to employees meeting early retirement eligibility criteria is fully expensed on the grant date. Dividend equivalents for certain equity-based awards are paid on stock units on a current basis prior to vesting and distribution. The 2017 Stock Incentive Plan, or 2017 Plan, was approved by shareholders in May 2017 for issuance of stock and stock based awards. Awards may be made under the 2017 Plan for (i) up to 8.3 million shares of common stock plus (ii) up to an additional 28.5 million shares that were available to be issued under the 2006 Equity Incentive Plan, or 2006 Plan, or may become available for issuance under the 2006 Plan due to expiration, termination, cancellation, forfeiture or repurchase of awards granted under the 2006 Plan. As of December 31, 2017, a total of 17.9 million shares from the 2006 Plan have been added to and may be issued from the 2017 Plan. As of December 31, 2017 , a cumulative total of 0.4 million shares had been awarded under the 2017 Plan and 68.9 million had been awarded under the 2006 Plan. As of December 31, 2016 and 2015, we had cumulative totals of 65.7 million shares and 60.9 million shares, respectively, awarded under the 2006 Plan. The 2017 Plan allows for shares withheld in payment of the exercise price of an award or in satisfaction of tax withholding requirements, shares forfeited due to employee termination, shares expired under options awards, or shares not delivered when performance conditions have not been met, to be added back to the pool of shares available for issuance under the 2017 Plan. From inception to December 31, 2017 , fewer than 1 million shares had been awarded under the 2017 Plan but not delivered, and have become available for reissue. As of December 31, 2017, a total of 25.9 million shares were available for future issuance under the 2017 Plan. The exercise price of non-qualified and incentive stock options and stock appreciation rights may not be less than the fair value of such shares on the date of grant. Stock options and stock appreciation rights granted under the 1997 Equity Incentive Plan, or 1997 Plan, and the 2006 Plan, collectively the Plans, generally vest over four years and expire no later than ten years from the date of grant. No common stock options or stock appreciation rights have been granted since 2009. For restricted stock awards granted under the Plans, common stock is issued at the time of grant and recipients have dividend and voting rights. In general, these grants vest over three to four years. As of December 31, 2017 there are no outstanding stock options or restricted stock awards. For deferred stock awards granted under the Plans, no common stock is issued at the time of grant and the award does not possess dividend and voting rights. Generally, these grants vest over one to four years. Performance awards granted are earned over a performance period based on the achievement of defined goals, generally over three years. Payment for performance awards is made in shares of our common stock equal to its fair market value per share, based on the performance of certain financial ratios, after the conclusion of each performance period. Beginning with 2012, malus-based forfeiture provisions were included in deferred stock awards granted to employees identified as “material risk-takers,” as defined by management. These malus-based forfeiture provisions provide for the reduction or cancellation of unvested deferred compensation, such as deferred stock awards and performance based awards, if it is determined that a material risk-taker made risk-based decisions that exposed State Street to inappropriate risks that resulted in a material unexpected loss at the business-unit, line-of-business or corporate level. In addition, awards granted to certain of our senior executives, as well as awards granted to individuals in certain jurisdictions, may be subject to recoupment after vesting (if applicable) and delivery to the individual in specified circumstances generally relating to fraud or willful misconduct by the individual that results in material harm to us or a material financial restatement. Compensation expense related to stock options, stock appreciation rights, restricted stock awards, deferred stock awards and performance awards, which we record as a component of compensation and employee benefits expense in our consolidated statement of income, was $243 million , $268 million and $319 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Such expense for 2017 , 2016 and 2015 excluded $15 million , $9 million and $10 million , respectively, associated with acceleration of expense in connection with targeted staff reductions. This expense was included in the severance-related portion of the associated restructuring charges recorded in each respective year. The following table presents information about the Plans as of December 31, 2017 , and related activity during the years indicated: Shares (In thousands) Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (In years) Total Intrinsic Value (In millions) Stock Appreciation Rights: Outstanding as of December 31, 2015 1,206 $ 76.29 Exercised (227 ) 70.59 Forfeited or expired (24 ) 81.71 Outstanding as of December 31, 2016 955 77.52 Exercised (595 ) 81.71 Forfeited or expired (360 ) 70.59 Outstanding and exercisable as of December 31, 2017 (1) — $ — 0 $ — (1) There were no shares subject to stock options and no stock appreciation rights. The total intrinsic value of stock appreciation rights exercised during the years ended December 31, 2017 , 2016 and 2015 was $5 million , $1 million and $5 million , respectively. As of December 31, 2017 , there was no unrecognized compensation cost related to stock options and stock appreciation rights. Shares (In thousands) Weighted-Average Grant Date Fair Value Deferred Stock Awards: Outstanding as of December 31, 2015 8,736 $ 61.59 Granted 4,336 52.49 Vested (4,897 ) 56.18 Forfeited (361 ) 60.12 Outstanding as of December 31, 2016 7,814 60.01 Granted 2,977 76.38 Vested (3,686 ) 62.88 Forfeited (257 ) 63.56 Outstanding as of December 31, 2017 6,848 $ 65.44 The total fair value of deferred stock awards vested for the years ended December 31, 2017 , 2016 and 2015 , based on the weighted average grant date fair value in each respective year, was $232 million , $275 million and $340 million , respectively. As of December 31, 2017 , total unrecognized compensation cost related to deferred stock awards, net of estimated forfeitures, was $242 million , which is expected to be recognized over a weighted-average period of 2.5 years. Shares (In thousands) Weighted-Average Grant Date Fair Value Performance Awards: Outstanding as of December 31, 2015 1,165 $ 60.45 Granted 506 50.81 Forfeited — — Paid out (424 ) 49.27 Outstanding as of December 31, 2016 1,247 60.37 Granted 534 76.27 Forfeited — — Paid out (233 ) 58.91 Outstanding as of December 31, 2017 1,548 $ 66.09 The total fair value of performance awards paid out for the years ended December 31, 2017 , 2016 and 2015 , based on the weighted average grant date fair value in each respective year, was $14 million , $21 million and $39 million , respectively. As of December 31, 2017 , total unrecognized compensation cost related to performance awards, net of estimated forfeitures, was $16 million , which is expected to be recognized over a weighted-average period of 2.8 years. We utilize either treasury shares or authorized but unissued shares to satisfy the issuance of common stock under our equity incentive plans. We do not have a specific policy concerning purchases of our common stock to satisfy stock issuances, including exercises of stock options. We have a general policy concerning purchases of our common stock to meet issuances under our employee benefit plans, including option exercises and other corporate purposes. Various factors determine the amount and timing of our purchases of our common stock, including regulatory reviews and approvals or non-objections, our regulatory capital requirements, the number of shares we expect to issue under employee benefit plans, market conditions (including the trading price of our common stock), and legal considerations. These factors can change at any time, and the number of shares of common stock we will purchase or when we will purchase them cannot be assured. See Note 15 for further information on our common stock purchase program.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee Benefits	Employee Benefits Defined Benefit Pension and Other Post-Retirement Benefit Plans State Street Bank and certain of its U.S. subsidiaries participate in a non-contributory, tax-qualified defined benefit pension plan. The U.S. defined benefit pension plan was frozen as of December 31, 2007 and no new employees were eligible to participate after that date. State Street has agreed to contribute sufficient amounts as necessary to meet the benefits paid to plan participants and to fund the plan’s service cost, plus interest. U.S. employee account balances earn annual interest credits until the employee begins receiving benefits. Non-U.S. employees participate in local defined benefit plans which are funded as required in each local jurisdiction. In addition to the defined benefit pension plans, we have non-qualified unfunded SERP s that provide certain officers with defined pension benefits in excess of allowable qualified plan limits. State Street Bank and certain of its U.S. subsidiaries also participate in a post-retirement plan that provides health care benefits for certain retired employees. The total expense for these tax-qualified and non-qualified plans was $15 million , $16 million and $46 million in 2017 , 2016 and 2015 , respectively. We recognize the funded status of our defined benefit pension plans and other post-retirement benefit plans, measured as the difference between the fair value of the plan assets and the projected benefit obligation, in the consolidated statement of position. The assets held by the defined benefit pension plans are largely made up of common, collective funds that are liquid and invest principally in U.S. equities and high-quality fixed income investments. The majority of these assets fall within Level 2 of the fair value hierarchy. The benefit obligations associated with our primary U.S. and non-U.S. defined benefit plans, non-qualified unfunded supplemental retirement plans and post-retirement plans were $1.32 billion , $125 million and $16 million , respectively, as of December 31, 2017 and $1.23 billion , $136 million and $21 million , respectively, as of December 31, 2016 . As the primary defined benefit plans are frozen, the benefit obligation will only vary over time as a result of changes in market interest rates, the life expectancy of the plan participants and payments made from the plans. The primary U.S. and non-U.S. defined benefit pension plans were underfunded by $9 million and $32 million as of December 31, 2017 and 2016 , respectively. The non-qualified supplemental retirement plans were underfunded by $125 million and $136 million as of December 31, 2017 and 2016 , respectively. The other post-retirement benefit plans were underfunded by $16 million and $21 million as of December 31, 2017 and 2016 , respectively. The underfunded status is included in other liabilities. Defined Contribution Retirement Plans We contribute to employer-sponsored U.S. and non-U.S. defined contribution plans. Our contribution to these plans was $146 million , $132 million , and $130 million in 2017 , 2016 and 2015 , respectively.

Occupancy Expense and Informati

Occupancy Expense and Information Systems and Communications Expense	12 Months Ended
	Dec. 31, 2017
Occupancy Expense and Information Systems and Communications Expense [Abstract]
Occupancy Expense and Information Systems and Communications Expense	Occupancy Expense and Information Systems and Communications Expense Occupancy expense and information systems and communications expense include depreciation of buildings, leasehold improvements, computer hardware and software, equipment, and furniture and fixtures. Total depreciation expense in 2017 , 2016 and 2015 was $526 million , $472 million and $443 million , respectively. We lease 1,025,000 square feet at One Lincoln Street, our headquarters building located in Boston, Massachusetts, and a related underground parking garage, under 20 -year, non-cancelable capital leases expiring in September 2023 . A portion of the lease payments is offset by subleases for approximately 127,000 square feet of the building. As of December 31, 2017 and 2016 , an aggregate net book value of $159 million and $194 million , respectively, related to the above-described capital leases was recorded in premises and equipment, with the related liability recorded in long-term debt, in our consolidated statement of condition. Capital lease asset amortization is recorded in occupancy expense on a straight-line basis in our consolidated statement of income over the respective lease term. Lease payments are recorded as a reduction of the liability, with a portion recorded as imputed interest expense. In 2017 , 2016 and 2015 , interest expense related to these capital lease obligations, reflected in NII, was $20 million , $22 million and $32 million , respectively. As of December 31, 2017 and 2016 , accumulated amortization of capital lease assets was $401 million and $365 million , respectively. We have entered into non-cancelable operating leases for premises and equipment. Nearly all of these leases include renewal options. Costs related to operating leases for office space are recorded in occupancy expense. Costs related to operating leases for equipment are recorded in information systems and communications expense. Both are recorded on a straight-line basis. Total rental expense net of sublease revenue in 2017 , 2016 and 2015 amounted to $229 million , $194 million and $190 million , respectively. Total rental expense was reduced by sublease revenue of $5 million in 2017 and $4 million in both 2016 and 2015 . The following table presents a summary of future minimum lease payments under non-cancelable capital and operating leases as of December 31, 2017 . Aggregate future minimum rental commitments have been reduced by aggregate sublease rental commitments of $41 million for capital leases and $19 million for operating leases. (In millions) Capital Leases Operating Leases Total 2018 $ 53 $ 197 $ 250 2019 45 175 220 2020 45 154 199 2021 45 144 189 2022 45 125 170 Thereafter 34 336 370 Total minimum lease payments 267 $ 1,131 $ 1,398 Less amount representing interest payments (56 ) Present value of minimum lease payments $ 211 Expenses The following table presents the components of other expenses for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Insurance $ 118 $ 93 $ 126 Regulatory fees and assessments 106 82 115 Bank operations 80 62 105 Sales advertising public relations 67 52 65 Litigation (15 ) 50 422 Other 233 245 185 Total other expenses $ 589 $ 584 $ 1,018 Restructuring Charges In the year ended December 31, 2017 , we recorded restructuring charges of $245 million , compared to $142 million in the year ended December 31, 2016 . The charges were primarily related to Beacon . The following table presents aggregate restructuring activity for the periods indicated: (In millions) Employee Real Estate Asset and Other Write-offs Total Accrual Balance at December 31, 2014 $ 39 $ 23 $ 7 $ 69 Accruals for Business Operations and IT (5 ) (3 ) 13 5 Payments and other adjustments (25 ) (9 ) (17 ) (51 ) Accrual Balance at December 31, 2015 $ 9 $ 11 $ 3 $ 23 Accruals for Business Operations and IT (2 ) — — (2 ) Accruals for Beacon 94 18 30 142 Payments and other adjustments (64 ) (12 ) (31 ) (107 ) Accrual Balance at December 31, 2016 $ 37 $ 17 $ 2 $ 56 Accruals for Beacon 186 32 27 245 Payments and Other Adjustments (57 ) (17 ) (26 ) (100 ) Accrual Balance at December 31, 2017 $ 166 $ 32 $ 3 $ 201

Expenses

Expenses	12 Months Ended
	Dec. 31, 2017
Other Expenses [Abstract]
Expenses	Occupancy Expense and Information Systems and Communications Expense Occupancy expense and information systems and communications expense include depreciation of buildings, leasehold improvements, computer hardware and software, equipment, and furniture and fixtures. Total depreciation expense in 2017 , 2016 and 2015 was $526 million , $472 million and $443 million , respectively. We lease 1,025,000 square feet at One Lincoln Street, our headquarters building located in Boston, Massachusetts, and a related underground parking garage, under 20 -year, non-cancelable capital leases expiring in September 2023 . A portion of the lease payments is offset by subleases for approximately 127,000 square feet of the building. As of December 31, 2017 and 2016 , an aggregate net book value of $159 million and $194 million , respectively, related to the above-described capital leases was recorded in premises and equipment, with the related liability recorded in long-term debt, in our consolidated statement of condition. Capital lease asset amortization is recorded in occupancy expense on a straight-line basis in our consolidated statement of income over the respective lease term. Lease payments are recorded as a reduction of the liability, with a portion recorded as imputed interest expense. In 2017 , 2016 and 2015 , interest expense related to these capital lease obligations, reflected in NII, was $20 million , $22 million and $32 million , respectively. As of December 31, 2017 and 2016 , accumulated amortization of capital lease assets was $401 million and $365 million , respectively. We have entered into non-cancelable operating leases for premises and equipment. Nearly all of these leases include renewal options. Costs related to operating leases for office space are recorded in occupancy expense. Costs related to operating leases for equipment are recorded in information systems and communications expense. Both are recorded on a straight-line basis. Total rental expense net of sublease revenue in 2017 , 2016 and 2015 amounted to $229 million , $194 million and $190 million , respectively. Total rental expense was reduced by sublease revenue of $5 million in 2017 and $4 million in both 2016 and 2015 . The following table presents a summary of future minimum lease payments under non-cancelable capital and operating leases as of December 31, 2017 . Aggregate future minimum rental commitments have been reduced by aggregate sublease rental commitments of $41 million for capital leases and $19 million for operating leases. (In millions) Capital Leases Operating Leases Total 2018 $ 53 $ 197 $ 250 2019 45 175 220 2020 45 154 199 2021 45 144 189 2022 45 125 170 Thereafter 34 336 370 Total minimum lease payments 267 $ 1,131 $ 1,398 Less amount representing interest payments (56 ) Present value of minimum lease payments $ 211 Expenses The following table presents the components of other expenses for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Insurance $ 118 $ 93 $ 126 Regulatory fees and assessments 106 82 115 Bank operations 80 62 105 Sales advertising public relations 67 52 65 Litigation (15 ) 50 422 Other 233 245 185 Total other expenses $ 589 $ 584 $ 1,018 Restructuring Charges In the year ended December 31, 2017 , we recorded restructuring charges of $245 million , compared to $142 million in the year ended December 31, 2016 . The charges were primarily related to Beacon . The following table presents aggregate restructuring activity for the periods indicated: (In millions) Employee Real Estate Asset and Other Write-offs Total Accrual Balance at December 31, 2014 $ 39 $ 23 $ 7 $ 69 Accruals for Business Operations and IT (5 ) (3 ) 13 5 Payments and other adjustments (25 ) (9 ) (17 ) (51 ) Accrual Balance at December 31, 2015 $ 9 $ 11 $ 3 $ 23 Accruals for Business Operations and IT (2 ) — — (2 ) Accruals for Beacon 94 18 30 142 Payments and other adjustments (64 ) (12 ) (31 ) (107 ) Accrual Balance at December 31, 2016 $ 37 $ 17 $ 2 $ 56 Accruals for Beacon 186 32 27 245 Payments and Other Adjustments (57 ) (17 ) (26 ) (100 ) Accrual Balance at December 31, 2017 $ 166 $ 32 $ 3 $ 201

Income Taxes (Notes)

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We use an asset-and-liability approach to account for income taxes. Our objective is to recognize the amount of taxes payable or refundable for the current year through charges or credits to the current tax provision, and to recognize deferred tax assets and liabilities for future tax consequences of temporary differences between amounts reported in our consolidated financial statements and their respective tax bases. The measurement of tax assets and liabilities is based on enacted tax laws and applicable tax rates. The effects of a tax position on our consolidated financial statements are recognized when we believe it is more likely than not that the position will be sustained. A valuation allowance is established if it is considered more likely than not that all or a portion of the deferred tax assets will not be realized. Deferred tax assets and liabilities recorded in our consolidated statement of condition are netted within the same tax jurisdiction. The following table presents the components of income tax expense (benefit) for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Current: Federal $ 229 $ (14 ) $ 52 State 18 30 92 Non-U.S. 380 320 342 Total current expense 627 336 486 Deferred: Federal 49 (311 ) (39 ) State 65 38 40 Non-U.S. (19 ) (85 ) (169 ) Total deferred expense (benefit) 95 (358 ) (168 ) Total income tax expense (benefit) $ 722 $ (22 ) $ 318 The following table presents a reconciliation of the U.S. statutory income tax rate to our effective tax rate based on income before income tax expense for the periods indicated: Years Ended December 31, 2017 2016 2015 U.S. federal income tax rate 35.0 % 35.0 % 35.0 % Changes from statutory rate: State taxes, net of federal benefit 1.9 2.0 4.2 Tax-exempt income (4.5 ) (6.1 ) (5.6 ) Business tax credits (1) (6.8 ) (13.6 ) (9.4 ) Foreign tax differential (7.4 ) (7.7 ) (9.6 ) Transition tax 15.7 — — Deferred tax revaluation (6.8 ) — — Foreign designated earnings (0.7 ) (6.8 ) — Foreign capital transactions — (4.3 ) — Tax refund — — (2.8 ) Litigation expense — 1.4 2.7 Other, net (1.5 ) (0.9 ) (0.7 ) Effective tax rate 24.9 % (1.0 )% 13.8 % (1) Business tax credits include low-income housing, production and investment tax credits. On December 22, 2017, the President signed into law the TCJA (H.R. 1), reducing the corporate income tax rate from 35% to 21% and enacting a one-time transition tax on unremitted earnings of foreign subsidiaries. Although we have not completed accounting for the tax effects of the TCJA, we included a provisional estimate for the impact to deferred tax balances and cost associated with the one-time transition tax. As a result of the reduction in the corporate income tax rate, certain U.S. deferred tax assets and liabilities were revalued resulting in a provisional estimated deferred tax benefit of $197 million . Deferred tax assets and liabilities represent the future impact on income taxes resulting from temporary differences that exist as of the balance sheet date using enacted tax rates. Certain U.S. temporary differences are a provisional estimate based on information currently available. As additional information is made available, there may be adjustments to temporary differences that could increase or decrease the deferred tax balances. As such, the $197 million benefit may be adjusted in future periods. The one-time transition tax is measured on total post-1986 earnings and profits ("E&P") of foreign subsidiaries previously deferred from U.S. income taxes. Although we have not completed our analysis of cumulative E&P, we have included a provisional expense of $454 million based on information available and our current interpretations of the newly enacted law. This amount is based on the amount of earnings held in cash and other specified assets. We understand that this amount will change as estimates of foreign E&P and foreign income taxes are refined and assumptions are modified from additional guidance on the TCJA. The 2016 foreign designated earnings include the benefits attributable to the change in designation of certain of our foreign earnings as indefinitely invested overseas. The foreign capital transactions include the tax benefits from incremental foreign tax credits and a foreign affiliate tax loss. The increase in business tax credits is attributable to an increase in alternative energy investments. In 2015 we recognized benefits associated with the reduction of an Italian deferred tax liability and the approval of a tax refund for prior years, partially offset by a change in New York tax law. The following table presents significant components of our gross deferred tax assets and gross deferred tax liabilities as of the dates indicated: December 31, (In millions) 2017 2016 Deferred tax assets: Unrealized losses on investment securities, net $ 17 $ 157 Deferred compensation 159 285 Defined benefit pension plan 82 116 Restructuring charges and other reserves 132 199 Foreign currency translation 18 225 General business credit 231 425 NOL and other carryforwards 101 73 Other 27 32 Total deferred tax assets 767 1,512 Valuation allowance for deferred tax assets (88 ) (66 ) Deferred tax assets, net of valuation allowance $ 679 $ 1,446 Deferred tax liabilities: Leveraged lease financing $ 184 $ 313 Fixed and intangible assets 755 886 Non-U.S. earnings 6 164 Investment basis differences 158 120 Total deferred tax liabilities $ 1,103 $ 1,483 The reduction in deferred tax assets and liabilities includes the provisional estimated impact of TCJA as well as current year activity such as the utilization of General Business Credits, additional investments in tax advantaged investments and changes in FX rates. The table below summarizes the deferred tax assets and related valuation allowances recognized as of December 31, 2017 : (In millions) Deferred Tax Asset Valuation Allowance Expiration General business Credits $ 231 $ — 2035-2037 NOLs - Non-U.S. 47 (35 ) 2018-2026 / None Other Carryforwards 41 (41 ) None NOLs - State 13 (12 ) 2018-2036 Management considers the valuation allowance adequate to reduce the total deferred tax assets to an aggregate amount that will more likely than not be realized. Management has determined that a valuation allowance is not required for the remaining deferred tax assets because it is more likely than not that there is sufficient taxable income of the appropriate nature within the carryforward periods to realize these assets. At December 31, 2017 , 2016 and 2015 , the gross unrecognized tax benefits, excluding interest, were $94 million , $71 million , and $63 million , respectively. Of this, the amounts that would reduce the effective tax rate, if recognized, are $87 million , $63 million and $55 million , respectively. Unrecognized tax benefits do not include the benefit of the federal deduction for unrecognized state tax benefits which is included in the effective tax rate. The following table presents activity related to unrecognized tax benefits as of the dates indicated: December 31, (In millions) 2017 2016 2015 Beginning balance $ 71 $ 63 $ 163 Decrease related to agreements with tax authorities (14 ) (13 ) (122 ) Increase related to tax positions taken during current year 26 7 8 Increase related to tax positions taken during prior years 11 14 14 Ending balance $ 94 $ 71 $ 63 It is reasonably possible that of the $94 million of unrecognized tax benefits as of December 31, 2017 , up to $14 million could decrease within the next 12 months due to the resolution of various audits. Management believes that we have sufficient accrued liabilities as of December 31, 2017 for tax exposures and related interest expense. Income tax expense included related interest and penalties of approximately $3 million and $2 million in 2017 and 2016 , respectively. Total accrued interest and penalties are approximately $8 million , $5 million and $3 million as of December 31, 2017 , 2016 and 2015 , respectively.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Basic EPS is calculated pursuant to the “two-class” method, by dividing net income available to common shareholders by the weighted-average common shares outstanding during the period. Diluted EPS is calculated pursuant to the two-class method, by dividing net income available to common shareholders by the total weighted-average number of common shares outstanding for the period plus the shares representing the dilutive effect of equity-based awards. The effect of equity-based awards is excluded from the calculation of diluted EPS in periods in which their effect would be anti-dilutive. The two-class method requires the allocation of undistributed net income between common and participating shareholders. Net income available to common shareholders, presented separately in our consolidated statement of income, is the basis for the calculation of both basic and diluted EPS. Participating securities are composed of unvested and fully vested SERP shares and fully vested deferred director stock awards, which are equity-based awards that contain non-forfeitable rights to dividends, and are considered to participate with the common stock in undistributed earnings. The following table presents the computation of basic and diluted earnings per common share for the periods indicated: Years Ended December 31, (Dollars in millions, except per share amounts) 2017 2016 2015 Net income $ 2,177 $ 2,143 $ 1,980 Less: Preferred stock dividends (182 ) (173 ) (130 ) Dividends and undistributed earnings allocated to participating securities (1) (2 ) (2 ) (2 ) Net income available to common shareholders $ 1,993 $ 1,968 $ 1,848 Average common shares outstanding (In thousands): Basic average common shares 374,793 391,485 407,856 Effect of dilutive securities: equity-based awards 5,420 4,605 5,782 Diluted average common shares 380,213 396,090 413,638 Anti-dilutive securities (2) 188 2,143 661 Earnings per Common Share: Basic $ 5.32 $ 5.03 $ 4.53 Diluted (3) 5.24 4.97 4.47 (1) Represents the portion of net income available to common equity allocated to participating securities, composed of unvested and fully vested SERP shares and fully vested deferred director stock awards, which are equity-based awards that contain non-forfeitable rights to dividends, and are considered to participate with the common stock in undistributed earnings. (2) Represents equity-based awards outstanding but not included in the computation of diluted average common shares, because their effect was anti-dilutive. Refer to Note 18 for additional information about equity-based awards. (3) Calculations reflect allocation of earnings to participating securities using the two-class method, as this computation is more dilutive than the treasury stock method.

Line of Business Information

Line of Business Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Line of Business Information	Line of Business Information Our operations are organized into two lines of business: Investment Servicing and Investment Management, which are defined based on products and services provided. The results of operations for these lines of business are not necessarily comparable with those of other companies, including companies in the financial services industry. Investment Servicing provides services for U.S. mutual funds, collective investment funds and other investment pools, corporate and public retirement plans, insurance companies, foundations and endowments worldwide. Products include custody; product and participant level accounting; daily pricing and administration; master trust and master custody; depotbank services (a fund oversight role created by regulation); record-keeping; cash management; foreign exchange, brokerage and other trading services; securities finance; our enhanced custody product, which integrates principal securities lending and custody; deposit and short-term investment facilities; loans and lease financing; investment manager and alternative investment manager operations outsourcing; performance, risk and compliance analytics; and financial data management to support institutional investors. Investment Management, through SSGA, provides a broad array of investment management, investment research and investment advisory services to corporations, public funds and other sophisticated investors. SSGA offers passive and active asset management strategies across equity, fixed-income, alternative, multi-asset solutions (including OCIO) and cash asset classes. Products are distributed directly and through intermediaries using a variety of investment vehicles, including ETFs, such as the SPDR ® ETF brand. Our investment servicing strategy is to focus on total client relationships and the full integration of our products and services across our client base through cross-selling opportunities. In general, our clients will use a combination of services, depending on their needs, rather than one product or service. For instance, a custody client may purchase securities finance and cash management services from different business units. Products and services that we provide to our clients are parts of an integrated offering to these clients. We price our products and services on the basis of overall client relationships and other factors; as a result, revenue may not necessarily reflect the stand-alone market price of these products and services within the business lines in the same way it would for separate business entities. Our servicing and management fee revenue from the Investment Servicing and Investment Management business lines, including trading services and securities finance activities, represents approximately 75% to 80% of our consolidated total revenue. The remaining 20% to 25% is composed of processing fees and other revenue as well as NII, which is largely generated by our investment of client deposits, short-term borrowings and long-term debt in a variety of assets, and net gains (losses) related to investment securities. These other revenue types are generally fully allocated to, or reside in, Investment Servicing and Investment Management. Revenue and expenses are directly charged or allocated to our lines of business through management information systems. Assets and liabilities are allocated according to policies that support management’s strategic and tactical goals. Capital is allocated based on the relative risks and capital requirements inherent in each business line, along with management judgment. Capital allocations may not be representative of the capital that might be required if these lines of business were separate business entities. The following is a summary of our line of business results for the periods indicated. The “Other” column for the year ended December 31, 2017 included net acquisition and restructuring costs of $266 million . The “Other” column for the year ended December 31, 2016 included net costs of $199 million composed of the following - • Net acquisition and restructuring costs of $209 million ; and • Net severance costs associated with staffing realignment of $(10) million . The “Other” column for the year ended December 31, 2015 included net costs of $98 million composed of the following - • Net acquisition and restructuring costs of $25 million ; • Net severance costs associated with staffing realignment of $73 million . The following is a summary of our line of business results for the periods indicated. The amounts in the “Other” columns were not allocated to State Street's business lines. Prior reported results reflect reclassifications, for comparative purposes, related to management changes in methodologies associated with allocations of revenue and expenses to lines of business in 2017 . Years Ended December 31, Investment Investment Other Total (Dollars in millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 Servicing fees $ 5,365 $ 5,073 $ 5,153 $ — $ — $ — $ — $ — $ — $ 5,365 $ 5,073 $ 5,153 Management fees — — — 1,616 1,292 1,174 — — — 1,616 1,292 1,174 Trading services 999 1,038 1,091 72 61 55 — — — 1,071 1,099 1,146 Securities finance 606 562 496 — — — — — — 606 562 496 Processing fees and other 240 119 342 7 (29 ) (33 ) — — — 247 90 309 Total fee revenue 7,210 6,792 7,082 1,695 1,324 1,196 — — — 8,905 8,116 8,278 Net interest income 2,309 2,081 2,086 (5 ) 3 2 — — — 2,304 2,084 2,088 Gains (losses) related to investment securities, net (39 ) 7 (6 ) — — — — — — (39 ) 7 (6 ) Total revenue 9,480 8,880 9,162 1,690 1,327 1,198 — — — 11,170 10,207 10,360 Provision for loan losses 2 10 12 — — — — — — 2 10 12 Total expenses 6,717 6,660 6,990 1,286 1,218 962 266 199 98 8,269 8,077 8,050 Income before income tax expense $ 2,761 $ 2,210 $ 2,160 $ 404 $ 109 $ 236 $ (266 ) $ (199 ) $ (98 ) $ 2,899 $ 2,120 $ 2,298 Pre-tax margin 29 % 25 % 24 % 24 % 8 % 20 % 26 % 21 % 22 % Average assets (in billions) $ 214.0 $ 225.3 $ 246.6 $ 5.4 $ 4.4 $ 3.9 $ 219.4 $ 229.7 $ 250.5

Non-U.S. Activities

Non-U.S. Activities	12 Months Ended
	Dec. 31, 2017
Segments, Geographical Areas [Abstract]
Non-U.S. Activities	Non-U.S. Activities We define our non-U.S. activities as those revenue-producing business activities that arise from clients which are generally serviced or managed outside the U.S. Due to the integrated nature of our business, precise segregation of our U.S. and non-U.S. activities is not possible. Subjective estimates, assumptions and other judgments are applied to quantify the financial results and assets related to our non-U.S. activities, including our application of funds transfer pricing, our asset-and-liability management policies and our allocation of certain indirect corporate expenses. Management periodically reviews and updates its processes for quantifying the financial results and assets related to our non-U.S. activities. Non-U.S. revenue in 2017 , 2016 and 2015 included $1.05 billion , $1.05 billion and $938 million , respectively, in the U.K. The following table presents our U.S. and non-U.S. financial results for the periods indicated: 2017 2016 2015 (In millions) Non-U.S. U.S. Total Non-U.S. U.S. Total Non-U.S. U.S. Total Total revenue $ 4,734 $ 6,436 $ 11,170 $ 4,419 $ 5,788 $ 10,207 $ 4,428 $ 5,932 $ 10,360 Income before income taxes 1,230 1,669 2,899 1,047 1,073 2,120 1,193 1,105 2,298 Non-U.S. assets were $82.1 billion and $79.1 billion as of December 31, 2017 and 2016 , respectively.

Parent Company Financial Statem

Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Financial Statements	Parent Company Financial Statements The following tables present the financial statements of the Parent Company without consolidation of its banking and non-banking subsidiaries, as of and for the years indicated: STATEMENT OF INCOME - PARENT COMPANY Years Ended December 31, (In millions) 2017 2016 2015 Cash dividends from consolidated banking subsidiary $ 2,224 $ 640 $ 585 Cash dividends from consolidated non-banking subsidiaries and unconsolidated entities 12 75 171 Other, net 127 92 73 Total revenue 2,363 807 829 Interest expense 297 249 209 Other expenses 94 107 310 Total expenses 391 356 519 Income tax benefit (86 ) (47 ) (186 ) Income before equity in undistributed income of consolidated subsidiaries and unconsolidated entities 2,058 498 496 Equity in undistributed income of consolidated subsidiaries and unconsolidated entities: Consolidated banking subsidiary 20 1,629 1,384 Consolidated non-banking subsidiaries and unconsolidated entities 99 16 100 Net income $ 2,177 $ 2,143 $ 1,980 STATEMENT OF CONDITION - PARENT COMPANY December 31, (In millions) 2017 2016 Assets: Interest-bearing deposits with consolidated banking subsidiary $ 532 $ 3,635 Trading account assets 361 325 Investment securities available-for-sale 43 39 Investments in subsidiaries: Consolidated banking subsidiary 23,080 22,147 Consolidated non-banking subsidiaries 6,762 2,687 Unconsolidated entities 63 297 Notes and other receivables from: Consolidated banking subsidiary 2,973 2,743 Consolidated non-banking subsidiaries and unconsolidated entities 143 126 Other assets 263 461 Total assets $ 34,220 $ 32,460 Liabilities: Accrued expenses and other liabilities $ 917 $ 514 Long-term debt 10,986 10,727 Total liabilities 11,903 11,241 Shareholders’ equity 22,317 21,219 Total liabilities and shareholders’ equity $ 34,220 $ 32,460 STATEMENT OF CASH FLOWS - PARENT COMPANY Years Ended December 31, (In millions) 2017 2016 2015 Net cash provided by operating activities $ 2,047 $ 417 $ 926 Investing Activities: Net decrease (increase) in interest-bearing deposits with consolidated banking subsidiary 3,103 2,100 295 Investments in consolidated banking and non-banking subsidiaries (7,672 ) (7,600 ) (7,959 ) Sale or repayment of investment in consolidated banking and non-banking subsidiaries 4,216 6,703 7,891 Business acquisitions — (395 ) — Net increase in investments in unconsolidated affiliates 172 — — Net cash provided by (used in) investing activities (181 ) 808 227 Financing Activities: Net increase (decrease) in commercial paper — — (2,485 ) Proceeds from issuance of long-term debt, net of issuance costs 748 1,492 2,983 Payments for long-term debt (450 ) (1,000 ) — Proceeds from issuance of preferred stock, net of issuance costs — 493 742 Proceeds from exercises of common stock options — — 4 Purchases of common stock (1,292 ) (1,365 ) (1,520 ) Repurchases of common stock for employee tax withholding (104 ) (122 ) (222 ) Payments for cash dividends (768 ) (723 ) (655 ) Net cash used in financing activities (1,866 ) (1,225 ) (1,153 ) Net change — — — Cash and due from banks at beginning of year — — — Cash and due from banks at end of year $ — $ — $ —

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accounting and financial reporting policies of State Street Corporation conform to U.S. GAAP. State Street Corporation, the Parent Company, is a financial holding company headquartered in Boston, Massachusetts. Unless otherwise indicated or unless the context requires otherwise, all references in these notes to consolidated financial statements to “State Street,” “we,” “us,” “our” or similar references mean State Street Corporation and its subsidiaries on a consolidated basis, including our principal banking subsidiary, State Street Bank. We have two lines of business: Investment Servicing provides products and services including: custody; product and participant level accounting; daily pricing and administration; master trust and master custody; depotbank services (a fund oversight role created by regulation); record-keeping; cash management; foreign exchange, brokerage and other trading services; securities finance; our enhanced custody product, which integrates principal securities lending and custody; deposit and short-term investment facilities; loans and lease financing; investment manager and alternative investment manager operations outsourcing; performance, risk and compliance analytics; and financial data management to support institutional investors. Investment Management , through SSGA, provides a broad array of investment management, investment research and investment advisory services to corporations, public funds and other sophisticated investors. SSGA offers passive and active asset management strategies across equity, fixed-income, alternative, multi-asset solutions (including OCIO) and cash asset classes. Products are distributed directly and through intermediaries using a variety of investment vehicles, including ETFs, such as the SPDR ® ETF brand.
Consolidation	Consolidation Our consolidated financial statements include the accounts of the Parent Company and its majority- and wholly-owned and otherwise controlled subsidiaries, including State Street Bank. All material inter-company transactions and balances have been eliminated. Certain previously reported amounts have been reclassified to conform to current-year presentation. We consolidate subsidiaries in which we exercise control. Investments in unconsolidated subsidiaries, recorded in other assets, generally are accounted for under the equity method of accounting if we have the ability to exercise significant influence over the operations of the investee. For investments accounted for under the equity method, our share of income or loss is recorded in processing fees and other revenue in our consolidated statement of income. Investments not meeting the criteria for equity-method treatment are accounted for under the cost method of accounting.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions in the application of certain of our significant accounting policies that may materially affect the reported amounts of assets, liabilities, equity, revenue, and expenses. As a result of unanticipated events or circumstances, actual results could differ from those estimates.
Foreign Currency Translation	Foreign Currency Translation The assets and liabilities of our operations with functional currencies other than the U.S. dollar are translated at month-end exchange rates, and revenue and expenses are translated at rates that approximate average monthly exchange rates. Gains or losses from the translation of the net assets of subsidiaries with functional currencies other than the U.S. dollar, net of related taxes, are recorded in AOCI, a component of shareholders’ equity.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of the consolidated statement of cash flows, cash and cash equivalents are defined as cash and due from banks.
Interest-Bearing Deposits With Banks	Interest-Bearing Deposits with Banks Interest-bearing deposits with banks generally consist of highly liquid, short-term investments maintained at the Federal Reserve Bank and other non-U.S. central banks with original maturities at the time of purchase of one month or less.
Securities Purchased Under Resale Agreements and Securities Sold Under Repurchase Agreements	Securities Purchased Under Resale Agreements and Securities Sold Under Repurchase Agreements Securities purchased under resale agreements and sold under repurchase agreements are treated as collateralized financing transactions, and are recorded in our consolidated statement of condition at the amounts at which the securities will be subsequently resold or repurchased, plus accrued interest. Our policy is to take possession or control of securities underlying resale agreements either directly or through agent banks, allowing borrowers the right of collateral substitution and/or short-notice termination. We revalue these securities daily to determine if additional collateral is necessary from the borrower to protect us against credit exposure. We can use these securities as collateral for repurchase agreements. For securities sold under repurchase agreements collateralized by our investment securities portfolio, the dollar value of the securities remains in investment securities in our consolidated statement of condition. Where a master netting agreement exists or both parties are members of a common clearing organization, resale and repurchase agreements with the same counterparty or clearing house and maturity date are recorded on a net basis.
Fee Revenue	Fees from investment servicing, investment management, securities finance, trading services and certain types of processing fees and other revenue are recorded in our consolidated statement of income based on estimates or specific contractual terms, including mutually agreed changes to terms, as transactions occur or services are rendered, provided that persuasive evidence exists, the price to the client is fixed or determinable and collectability is reasonably assured. Amounts accrued at period-end are recorded in accrued interest and fees receivable in our consolidated statement of condition. Performance fees generated by our investment management activities are recorded when the performance period is complete, based on predetermined benchmarks associated with the applicable fund’s performance.
Net Interest Revenue	Interest income on interest-earning assets and interest expense on interest-bearing liabilities are recorded in our consolidated statement of income as components of NII, and are generally based on the effective yield of the related financial asset or liability.
Recent Accounting Developments	Recent Accounting Developments Relevant standards that were recently issued but not yet adopted Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2014-09, Revenue from Contracts with Customers (Topic 606) The standard, and its related amendments, will replace existing revenue recognition standards and expand the disclosure requirements for revenue arrangements with customers. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). January 1, 2018 The timing and amount of our material revenue streams, including servicing fees, management fees, trading services, and securities finance, remain substantially unchanged as these revenues will continue to be recognized over time. Specifically, under the new standard we will recognize revenue related to these activities ratably over the term of the related agreements with customers as the customer simultaneously benefits from the services as they are performed. The standard does not apply to revenue associated with financial instruments, including loans and securities, or revenue recognized under other U.S. GAAP standards. Therefore NII, securities gains/ losses and revenue related to derivative instruments are not impacted by the standard. The new standard modified the principal and agent guidance requiring certain costs previously presented on a net basis to be presented on a gross basis, which we expect will increase 2018 revenue and expenses by an estimated $225 million, the majority reflected in Investment Management. We have adopted the new standard as of January 1, 2018, using the modified retrospective method of adoption. No material adjustment to retained earnings was required. ASU 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard makes limited amendments to the guidance on the classification and measurement of financial instruments. Under the new standard, all equity securities will be measured at fair value through earnings with certain exceptions, including investments accounted for under the equity method of accounting. In addition, the FASB clarified the guidance related to valuation allowance assessments when recognizing deferred tax assets on unrealized losses on available-for-sale debt securities. This standard must be applied on a retrospective basis. January 1, 2018 Upon adoption of the standard on January 1, 2018, we reclassified approximately $443 million of equity securities classified as available for sale to equity securities held at fair value through profit and loss. The cumulative-effect transition adjustment recognized in retained earnings on January 1, 2018 was immaterial to the financial statements. ASU 2016-02, Leases (Topic 842) The standard represents a wholesale change to lease accounting and requires all leases, other than short-term leases, to be reported on balance sheet through recognition of a right-of-use asset and a corresponding liability for future lease obligations. The standard also requires extensive disclosures for assets, expenses, and cash flows associated with leases, as well as a maturity analysis of lease liabilities. January 1, 2019 We are currently assessing the impact of the standard on our consolidated financial statements, but we anticipate an increase in assets and liabilities due to the recognition of the required right-of-use asset and corresponding liability for all lease obligations that are currently classified as operating leases, primarily real estate leases for office space, as well as additional disclosure on all of our lease obligations. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments The standard requires immediate recognition of expected credit losses for financial assets carried at amortized cost, including trade and other receivables, loans and commitments, held-to-maturity debt securities, and other financial assets, held at the reporting date to be measured based on historical experience, current conditions, and reasonable supportable forecasts. Credit losses on available for sale securities will be recorded as an allowance versus a write-down of the amortized cost basis of the security and will allow for a reversal of impairment loss when the credit of the issuer improves. January 1, 2020 We are currently assessing the impact of the standard on our consolidated financial statements, and a significant implementation project is in place to ensure that expected credit losses are calculated in accordance with the standard. We have established a steering committee to provide cross-functional governance over the project plan and key decisions, and are currently developing key accounting policies, assessing existing credit loss models against the new guidance and processes and identifying a complete set of data requirements and sources. We have commenced the development of new or modified credit loss models and based on our analysis to date, we expect the timing of the allowance for credit losses to accelerate under the new standard. We are continuing to assess the extent of the impact on the allowance for credit losses. Relevant standards that were recently issued but not yet adopted (continued) Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) The standard amends the statement of cash flow guidance to address specific cash flow issues with the objective of reducing the existing diversity in practice. January 1, 2018 Based on our current presentation there is no significant change to our presentation of the statement of cash flows. ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business The standard incorporates gating criteria to determine when an integrated set of assets and activities is not a business. When substantially all the fair value of gross assets acquired (or group of similar identifiable assets) is concentrated in a single identifiable asset, it would not represent a business. January 1, 2018, early adoption permitted We have adopted this standard as of January 1, 2018 and will apply it prospectively to transactions occurring after adoption date, as applicable. ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment The standard simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. The ASU requires an entity to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying value exceeds the fair value of the reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss. January 1, 2020, early adoption permitted We are evaluating the impacts of early adoption, and will apply this standard prospectively upon adoption. ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities The standard shortens the amortization period for certain purchased callable debt securities to the earliest call date. January 1, 2019, early adoption permitted We are currently evaluating the impact of the new standard and the early adoption provisions. ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities The standard amends the hedge accounting model to better portray the economics of risk management activities in the financial statements and enhances the presentation of hedge results. The amendments also make targeted changes to simplify the application of hedge accounting in certain situations. January 1, 2019, early adoption permitted We are currently evaluating the impact of the new standard and the early adoption provisions. Relevant standards that were adopted during the year ended December 31, 2017 We adopted ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, effective January 1, 2017. Starting in the quarter ended March 31, 2017, we reclassified excess tax benefits related to stock-based compensation from financing activities to other operating activities on the consolidated statement of cash flows. We continued to present repurchases of common stock for employee tax withholding in financing activities in the consolidated statements of cash flows for all periods presented. As required by the transition provisions of the standard, excess tax benefits previously recognized in surplus prior to January 1, 2017 remain in surplus, and excess tax benefits recognized after January 1, 2017 are included in income tax expense. In connection with this change, we recognized a tax benefit of $24.8 million in the year ended December 31, 2017. We elected to make no changes to our current policy of estimating forfeitures or our tax withholding rates.
Fair Value Measurements	Fair Value Measurements We carry trading account assets and liabilities, AFS investment securities and various types of derivative financial instruments at fair value in our consolidated statement of condition on a recurring basis. Changes in the fair values of these financial assets and liabilities are recorded either as components of our consolidated statement of income or as components of AOCI within shareholders' equity in our consolidated statement of condition. We measure fair value for the above-described financial assets and liabilities in conformity with U.S. GAAP that governs the measurement of the fair value of financial instruments. Management believes that its valuation techniques and underlying assumptions used to measure fair value conform to the provisions of U.S. GAAP. We categorize the financial assets and liabilities that we carry at fair value based on a prescribed three-level valuation hierarchy. The hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (level 1) and the lowest priority to valuation methods using significant unobservable inputs (level 3). If the inputs used to measure a financial asset or liability cross different levels of the hierarchy, categorization is based on the lowest-level input that is significant to the fair-value measurement. Management's assessment of the significance of a particular input to the overall fair-value measurement of a financial asset or liability requires judgment, and considers factors specific to that asset or liability. The three levels of the valuation hierarchy are described below. Level 1. Financial assets and liabilities with values based on unadjusted quoted prices for identical assets or liabilities in an active market. Our level 1 financial assets and liabilities primarily include positions in U.S. government securities and highly liquid U.S. and non-U.S. government fixed-income securities carried in trading account assets. We may carry U.S. government securities in our AFS portfolio in connection with our asset-and-liability management activities. Our level 1 financial assets also include active exchange-traded equity securities. Level 2. Financial assets and liabilities with values based on quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. Level 2 inputs include the following: • Quoted prices for similar assets or liabilities in active markets; • Quoted prices for identical or similar assets or liabilities in non-active markets; • Pricing models whose inputs are observable for substantially the full term of the asset or liability; and • Pricing models whose inputs are derived principally from, or corroborated by, observable market information through correlation or other means for substantially the full term of the asset or liability. Our level 2 financial assets and liabilities primarily include non-U.S. debt securities carried in trading account assets and various types of fixed-income investment securities available-for-sale, as well as various types of foreign exchange and interest-rate derivative instruments. Fair value for our investment securities available-for-sale categorized in level 2 is measured primarily using information obtained from independent third parties. This third-party information is subject to review by management as part of a validation process, which includes obtaining an understanding of the underlying assumptions and the level of market participant information used to support those assumptions. In addition, management compares significant assumptions used by third parties to available market information. Such information may include known trades or, to the extent that trading activity is limited, comparisons to market research information pertaining to credit expectations, execution prices and the timing of cash flows and, where information is available, back-testing. Derivative instruments categorized in level 2 predominantly represent foreign exchange contracts used in our trading activities, for which fair value is measured using discounted cash-flow techniques, with inputs consisting of observable spot and forward points, as well as observable interest-rate curves. With respect to derivative instruments, we evaluate the impact on valuation of the credit risk of our counterparties and our own credit risk. We consider factors such as the likelihood of default by us and our counterparties, our current and potential future net exposures and remaining maturities in determining the fair value. Valuation adjustments associated with derivative instruments were not material to those instruments for the years ended December 31, 2017 and 2016 . Level 3. Financial assets and liabilities with values based on prices or valuation techniques that require inputs that are both unobservable in the market and significant to the overall measurement of fair value. These inputs reflect management's judgment about the assumptions that a market participant would use in pricing the financial asset or liability, and are based on the best available information, some of which is internally developed. The following provides a more detailed discussion of our financial assets and liabilities that we may categorize in level 3 and the related valuation methodology. • The fair value of our investment securities categorized in level 3 is measured using information obtained from third-party sources, typically non-binding broker or dealer quotes, or through the use of internally-developed pricing models. Management has evaluated its methodologies used to measure fair value, but has considered the level of observable market information to be insufficient to categorize the securities in level 2. • The fair value of certain foreign exchange contracts, primarily options, is measured using an option-pricing model. Because of a limited number of observable transactions, certain model inputs are not observable, such as implied volatility surface, but are derived from observable market information. Our level 3 financial assets and liabilities are similar in structure and profile to our level 1 and level 2 financial instruments, but they trade in less liquid markets, and the measurement of their fair value is inherently more difficult.

Summary of Significant Accoun37

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Recent Accounting Developments	Recent Accounting Developments Relevant standards that were recently issued but not yet adopted Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2014-09, Revenue from Contracts with Customers (Topic 606) The standard, and its related amendments, will replace existing revenue recognition standards and expand the disclosure requirements for revenue arrangements with customers. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). January 1, 2018 The timing and amount of our material revenue streams, including servicing fees, management fees, trading services, and securities finance, remain substantially unchanged as these revenues will continue to be recognized over time. Specifically, under the new standard we will recognize revenue related to these activities ratably over the term of the related agreements with customers as the customer simultaneously benefits from the services as they are performed. The standard does not apply to revenue associated with financial instruments, including loans and securities, or revenue recognized under other U.S. GAAP standards. Therefore NII, securities gains/ losses and revenue related to derivative instruments are not impacted by the standard. The new standard modified the principal and agent guidance requiring certain costs previously presented on a net basis to be presented on a gross basis, which we expect will increase 2018 revenue and expenses by an estimated $225 million, the majority reflected in Investment Management. We have adopted the new standard as of January 1, 2018, using the modified retrospective method of adoption. No material adjustment to retained earnings was required. ASU 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard makes limited amendments to the guidance on the classification and measurement of financial instruments. Under the new standard, all equity securities will be measured at fair value through earnings with certain exceptions, including investments accounted for under the equity method of accounting. In addition, the FASB clarified the guidance related to valuation allowance assessments when recognizing deferred tax assets on unrealized losses on available-for-sale debt securities. This standard must be applied on a retrospective basis. January 1, 2018 Upon adoption of the standard on January 1, 2018, we reclassified approximately $443 million of equity securities classified as available for sale to equity securities held at fair value through profit and loss. The cumulative-effect transition adjustment recognized in retained earnings on January 1, 2018 was immaterial to the financial statements. ASU 2016-02, Leases (Topic 842) The standard represents a wholesale change to lease accounting and requires all leases, other than short-term leases, to be reported on balance sheet through recognition of a right-of-use asset and a corresponding liability for future lease obligations. The standard also requires extensive disclosures for assets, expenses, and cash flows associated with leases, as well as a maturity analysis of lease liabilities. January 1, 2019 We are currently assessing the impact of the standard on our consolidated financial statements, but we anticipate an increase in assets and liabilities due to the recognition of the required right-of-use asset and corresponding liability for all lease obligations that are currently classified as operating leases, primarily real estate leases for office space, as well as additional disclosure on all of our lease obligations. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments The standard requires immediate recognition of expected credit losses for financial assets carried at amortized cost, including trade and other receivables, loans and commitments, held-to-maturity debt securities, and other financial assets, held at the reporting date to be measured based on historical experience, current conditions, and reasonable supportable forecasts. Credit losses on available for sale securities will be recorded as an allowance versus a write-down of the amortized cost basis of the security and will allow for a reversal of impairment loss when the credit of the issuer improves. January 1, 2020 We are currently assessing the impact of the standard on our consolidated financial statements, and a significant implementation project is in place to ensure that expected credit losses are calculated in accordance with the standard. We have established a steering committee to provide cross-functional governance over the project plan and key decisions, and are currently developing key accounting policies, assessing existing credit loss models against the new guidance and processes and identifying a complete set of data requirements and sources. We have commenced the development of new or modified credit loss models and based on our analysis to date, we expect the timing of the allowance for credit losses to accelerate under the new standard. We are continuing to assess the extent of the impact on the allowance for credit losses. Relevant standards that were recently issued but not yet adopted (continued) Standard Description Date of Adoption Effects on the financial statements or other significant matters ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) The standard amends the statement of cash flow guidance to address specific cash flow issues with the objective of reducing the existing diversity in practice. January 1, 2018 Based on our current presentation there is no significant change to our presentation of the statement of cash flows. ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business The standard incorporates gating criteria to determine when an integrated set of assets and activities is not a business. When substantially all the fair value of gross assets acquired (or group of similar identifiable assets) is concentrated in a single identifiable asset, it would not represent a business. January 1, 2018, early adoption permitted We have adopted this standard as of January 1, 2018 and will apply it prospectively to transactions occurring after adoption date, as applicable. ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment The standard simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. The ASU requires an entity to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying value exceeds the fair value of the reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss. January 1, 2020, early adoption permitted We are evaluating the impacts of early adoption, and will apply this standard prospectively upon adoption. ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities The standard shortens the amortization period for certain purchased callable debt securities to the earliest call date. January 1, 2019, early adoption permitted We are currently evaluating the impact of the new standard and the early adoption provisions. ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities The standard amends the hedge accounting model to better portray the economics of risk management activities in the financial statements and enhances the presentation of hedge results. The amendments also make targeted changes to simplify the application of hedge accounting in certain situations. January 1, 2019, early adoption permitted We are currently evaluating the impact of the new standard and the early adoption provisions.

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Fair Value Measurements on a Recurring Basis as of December 31, 2017 (In millions) Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) Impact of Netting (1) Total Net Carrying Value in Consolidated Statement of Condition Assets: Trading account assets: U.S. government securities $ 39 $ — $ — $ 39 Non-U.S. government securities 389 93 — 482 Other 44 528 — 572 Total trading account assets 472 621 — 1,093 AFS investment securities: U.S. Treasury and federal agencies: Direct obligations 11 212 — 223 Mortgage-backed securities — 10,872 — 10,872 Total U.S. Treasury and federal agencies 11 11,084 — 11,095 Asset-backed securities: Student loans — 3,358 — 3,358 Credit cards — 1,542 — 1,542 Other (2) — 89 1,358 1,447 Total asset-backed securities — 4,989 1,358 6,347 Non-U.S. debt securities: Mortgage-backed securities — 6,576 119 6,695 Asset-backed securities — 2,545 402 2,947 Government securities — 10,721 — 10,721 Other (3) — 5,904 204 6,108 Total non-U.S. debt securities — 25,746 725 26,471 State and political subdivisions — 9,108 43 9,151 Collateralized mortgage obligations — 1,054 — 1,054 Other U.S. debt securities — 2,560 — 2,560 U.S. equity securities — 46 — 46 U.S. money-market mutual funds — 397 — 397 Total AFS investment securities 11 54,984 2,126 57,121 Other assets: Derivative instruments: Foreign exchange contracts — 11,596 1 $ (7,593 ) 4,004 Interest-rate contracts 8 — — — 8 Other derivative contracts 1 — — — 1 Total derivative instruments 9 11,596 1 (7,593 ) 4,013 Total assets carried at fair value $ 492 $ 67,201 $ 2,127 $ (7,593 ) $ 62,227 Liabilities: Accrued expenses and other liabilities: Trading account liabilities: Other $ 39 $ — $ — $ — $ 39 Derivative instruments: Foreign exchange contracts — 11,467 1 (5,970 ) 5,498 Interest-rate contracts — 100 — — 100 Other derivative contracts 1 283 — — 284 Total derivative instruments 1 11,850 1 (5,970 ) 5,882 Total liabilities carried at fair value $ 40 $ 11,850 $ 1 $ (5,970 ) $ 5,921 (1) Represents counterparty netting against level 2 financial assets and liabilities where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $2,045 million and $422 million , respectively, for cash collateral received from and provided to derivative counterparties. (2) As of December 31, 2017 , the fair value of other ABS was primarily composed of $1,447 million of CLOs. (3) As of December 31, 2017 , the fair value of other non-U.S. debt securities was primarily composed of $3,537 million of covered bonds and $1,885 million of corporate bonds. Fair Value Measurements on a Recurring Basis as of December 31, 2016 (In millions) Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) Impact of Netting (1) Total Net Carrying Value in Consolidated Statement of Condition Assets: Trading account assets: U.S. government securities $ 30 $ — $ — $ 30 Non-U.S. government securities 495 174 — 669 Other — 325 — 325 Total trading account assets 525 499 — 1,024 AFS investment securities: U.S. Treasury and federal agencies: Direct obligations 3,824 439 — 4,263 Mortgage-backed securities — 13,257 — 13,257 Total U.S. Treasury and federal agencies 3,824 13,696 — 17,520 Asset-backed securities: Student loans — 5,499 97 5,596 Credit cards — 1,351 — 1,351 Sub-prime — 272 — 272 Other (2) — — 905 905 Total asset-backed securities — 7,122 1,002 8,124 Non-U.S. debt securities: Mortgage-backed securities — 6,535 — 6,535 Asset-backed securities — 2,484 32 2,516 Government securities — 5,836 — 5,836 Other (3) — 5,365 248 5,613 Total non-U.S. debt securities — 20,220 280 20,500 State and political subdivisions — 10,283 39 10,322 Collateralized mortgage obligations — 2,577 16 2,593 Other U.S. debt securities — 2,469 — 2,469 U.S. equity securities — 42 — 42 Non-U.S. equity securities — 3 — 3 U.S. money-market mutual funds — 409 — 409 Non-U.S. money-market mutual funds — 16 — 16 Total AFS investment securities 3,824 56,837 1,337 61,998 Other assets: Derivatives instruments: Foreign exchange contracts — 16,476 8 $ (9,163 ) 7,321 Interest-rate contracts — 68 — (68 ) — Total derivative instruments — 16,544 8 (9,231 ) 7,321 Total assets carried at fair value $ 4,349 $ 73,880 $ 1,345 $ (9,231 ) $ 70,343 Liabilities: Accrued expenses and other liabilities: Derivative instruments: Foreign exchange contracts $ — $ 15,948 $ 8 $ (10,456 ) $ 5,500 Interest-rate contracts — 348 — (226 ) 122 Other derivative contracts — 380 — — 380 Total derivative instruments — 16,676 8 (10,682 ) 6,002 Total liabilities carried at fair value $ — $ 16,676 $ 8 $ (10,682 ) $ 6,002 (1) Represents counterparty netting against level 2 financial assets and liabilities where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $906 million and $2,356 million , respectively, for cash collateral received from and provided to derivative counterparties. (2) As of December 31, 2016 , the fair value of other ABS was primarily composed of $905 million of CLOs. (3) As of December 31, 2016 , the fair value of other non-U.S. debt securities was primarily composed of $3,769 million of covered bonds and $988 million of corporate bonds.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following tables present activity related to our level 3 financial assets during the years ended December 31, 2017 and 2016 , respectively. Transfers into and out of level 3 are reported as of the beginning of the period presented. During the year ended December 31, 2017 , transfers into level 3 were mainly related to certain ABS and MBS, including non-U.S. debt securities, and municipal loans for which fair value was measured using information obtained from third-party sources, including non-binding broker or dealer quotes. During the years ended December 31, 2017 and 2016 , transfers out of level 3 were mainly related to certain MBS and ABS, including non-U.S. debt securities, for which fair value was measured using prices for which observable market information became available. Fair Value Measurements Using Significant Unobservable Inputs Year Ended December 31, 2017 Fair Value as of Total Realized and Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Fair Value as of December 31, 2017 (1) Change in (In millions) Recorded in Revenue (1) Recorded in Other Comprehensive Income (1) Assets: AFS Investment securities: U.S. Treasury and federal agencies: Mortgage-backed securities $ — $ — $ — $ — $ — $ — $ 25 $ (25 ) $ — Asset-backed securities: Student loans 97 — 1 200 — — — (298 ) — Other 905 3 — 1,035 (240 ) (620 ) 275 — 1,358 Total asset-backed securities 1,002 3 1 1,235 (240 ) (620 ) 275 (298 ) 1,358 Non-U.S. debt securities: Mortgage-backed securities — — (2 ) 119 — 2 — — 119 Asset-backed securities 32 1 — 370 (10 ) (11 ) 67 (47 ) 402 Other 248 — 1 5 (81 ) 31 — — 204 Total non-U.S. debt securities 280 1 (1 ) 494 (91 ) 22 67 (47 ) 725 State and political subdivisions 39 — 2 — — (3 ) 5 — 43 Collateralized mortgage obligations 16 — (1 ) 24 — — — (39 ) — Other U.S. debt securities — — — 19 (19 ) — — — — Total AFS investment securities 1,337 4 1 1,772 (350 ) (601 ) 372 (409 ) 2,126 Other assets: Derivative instruments: Foreign exchange contracts 8 (7 ) — 4 — (4 ) — — 1 $ (3 ) Total derivative instruments 8 (7 ) — 4 — (4 ) — — 1 (3 ) Total assets carried at fair value $ 1,345 $ (3 ) $ 1 $ 1,776 $ (350 ) $ (605 ) $ 372 $ (409 ) $ 2,127 $ (3 ) (1) Total realized and unrealized gains (losses) on AFS investment securities are included within gains (losses) related to investment securities, net. Total realized and unrealized gains (losses) on derivative instruments are included within trading services. Fair Value Measurements Using Significant Unobservable Inputs Year Ended December 31, 2016 Fair Value as of December 31, 2015 Total Realized and Purchases Sales Settlements Transfers Fair Value as of December 31, (2) Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of December 31, 2016 (In millions) Recorded (1) Recorded (1) Assets: AFS Investment securities: U.S. Treasury and federal agencies, mortgage-backed securities $ — $ — $ — $ 325 $ — $ — $ (325 ) $ — Asset-backed securities: Student loans 189 1 3 — $ — — (96 ) 97 Other 1,764 31 (23 ) 469 (82 ) (1,254 ) — 905 Total asset-backed securities 1,953 32 (20 ) 469 (82 ) (1,254 ) (96 ) 1,002 Non-U.S. debt securities: Mortgage-backed securities — — — 90 — — (90 ) — Asset-backed securities 174 — — 196 — (60 ) (278 ) 32 Other 255 — — 222 — (7 ) (222 ) 248 Total non-U.S. debt securities 429 — — 508 — (67 ) (590 ) 280 State and political subdivisions 33 — 9 — — (3 ) — 39 Collateralized mortgage obligations 39 — 2 89 (66 ) (27 ) (21 ) 16 Other U.S. debt securities 10 — — — — (10 ) — — Total AFS investment securities 2,464 32 (9 ) 1,391 (148 ) (1,361 ) (1,032 ) 1,337 Other assets: Derivative instruments: Foreign exchange contracts 5 9 — 3 — (9 ) — 8 $ 5 Total derivative instruments 5 9 — 3 — (9 ) — 8 5 Total assets carried at fair value $ 2,469 $ 41 $ (9 ) $ 1,394 $ (148 ) $ (1,370 ) $ (1,032 ) $ 1,345 $ 5 (1) Total realized and unrealized gains (losses) on AFS investment securities are included within gains (losses) related to investment securities, net. Total realized and unrealized gains (losses) on derivative instruments are included within trading services. (2) There were no transfers of assets into level 3 during the year ended December 31, 2016 .
Fair Value Inputs, Assets, Quantitative Information	The following table presents quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our level 3 financial assets and liabilities measured at fair value on a recurring basis for which we use internally-developed pricing models. The significant unobservable inputs for our level 3 financial assets and liabilities whose fair value is measured using pricing information from non-binding broker or dealer quotes are not included in the table, as the specific inputs applied are not provided by the broker/dealer. Quantitative Information about Level 3 Fair Value Measurements Fair Value Weighted-Average (Dollars in millions) As of December 31, 2017 As of December 31, 2016 Valuation Technique Significant (1) As of December 31, 2017 As of December 31, 2016 Significant unobservable inputs readily available to State Street: Assets: Asset-backed securities, other $ — $ 1 Discounted cash flows Credit spread — % 0.3 % State and political subdivisions — 39 Discounted cash flows Credit spread — 1.8 Derivative instruments, foreign exchange contracts 1 8 Option model Volatility 7.2 14.4 Total $ 1 $ 48 Liabilities: Derivative instruments, foreign exchange contracts $ 1 $ 8 Option model Volatility 7.2 14.4 Total $ 1 $ 8 (1) Significant chan ges in these unobservable inputs would result in significant changes in fair value measurement.
Fair Value Inputs, Liabilities, Quantitative Information	The following table presents quantitative information, as of the dates indicated, about the valuation techniques and significant unobservable inputs used in the valuation of our level 3 financial assets and liabilities measured at fair value on a recurring basis for which we use internally-developed pricing models. The significant unobservable inputs for our level 3 financial assets and liabilities whose fair value is measured using pricing information from non-binding broker or dealer quotes are not included in the table, as the specific inputs applied are not provided by the broker/dealer. Quantitative Information about Level 3 Fair Value Measurements Fair Value Weighted-Average (Dollars in millions) As of December 31, 2017 As of December 31, 2016 Valuation Technique Significant (1) As of December 31, 2017 As of December 31, 2016 Significant unobservable inputs readily available to State Street: Assets: Asset-backed securities, other $ — $ 1 Discounted cash flows Credit spread — % 0.3 % State and political subdivisions — 39 Discounted cash flows Credit spread — 1.8 Derivative instruments, foreign exchange contracts 1 8 Option model Volatility 7.2 14.4 Total $ 1 $ 48 Liabilities: Derivative instruments, foreign exchange contracts $ 1 $ 8 Option model Volatility 7.2 14.4 Total $ 1 $ 8 (1) Significant chan ges in these unobservable inputs would result in significant changes in fair value measurement.
Carrying Value and Estimated Fair Value of Financial Instruments by Fair Value Hierarchy	The following tables present the reported amounts and estimated fair values of the financial assets and liabilities not carried at fair value on a recurring basis, as they would be categorized within the fair value hierarchy, as of the dates indicated. Fair Value Hierarchy (In millions) Reported Amount Estimated Fair Value Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) December 31, 2017 Financial Assets: Cash and due from banks $ 2,107 $ 2,107 $ 2,107 $ — $ — Interest-bearing deposits with banks 67,227 67,227 — 67,227 — Securities purchased under resale agreements 3,241 3,241 — 3,241 — Investment securities held-to-maturity 40,458 40,255 16,814 23,318 123 Net loans (excluding leases) (1) 22,577 22,482 — 22,431 51 Financial Liabilities: Deposits: Non-interest-bearing $ 47,175 $ 47,175 $ — $ 47,175 $ — Interest-bearing - U.S. 50,139 50,139 — 50,139 — Interest-bearing - non-U.S. 87,582 87,582 — 87,582 — Securities sold under repurchase agreements 2,842 2,842 — 2,842 — Other short-term borrowings 1,144 1,144 — 1,144 — Long-term debt 11,620 11,919 — 11,639 280 (1) Includes $3 million of loans classified as held-for-sale that were measured at fair value on a non-recurring basis as of December 31, 2017. Fair Value Hierarchy (In millions) Reported Amount Estimated Fair Value Quoted Market Prices in Active Markets (Level 1) Pricing Methods with Significant Observable Market Inputs (Level 2) Pricing Methods with Significant Unobservable Market Inputs (Level 3) December 31, 2016 Financial Assets: Cash and due from banks $ 1,314 $ 1,314 $ 1,314 $ — $ — Interest-bearing deposits with banks 70,935 70,935 — 70,935 — Securities purchased under resale agreements 1,956 1,956 — 1,956 — Investment securities held-to-maturity 35,169 34,994 17,400 17,439 155 Net loans (excluding leases) 18,862 18,877 — 18,781 96 Financial Liabilities: Deposits: Non-interest-bearing $ 59,397 $ 59,397 $ — $ 59,397 $ — Interest-bearing - U.S. 30,911 30,911 — 30,911 — Interest-bearing - non-U.S. 96,855 96,855 — 96,855 — Securities sold under repurchase agreements 4,400 4,400 — 4,400 — Other short-term borrowings 1,585 1,585 — 1,585 — Long-term debt 11,430 11,618 — 11,282 336

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of Marketable Securities	The following table presents the amortized cost, fair value and associated unrealized gains and losses of investment securities as of the dates indicated: December 31, 2017 December 31, 2016 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value (In millions) Gains Losses Gains Losses Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ 222 $ 2 $ 1 $ 223 $ 4,265 $ 7 $ 9 $ 4,263 Mortgage-backed securities 10,975 26 129 10,872 13,340 76 159 13,257 Total U.S. Treasury and federal agencies 11,197 28 130 11,095 17,605 83 168 17,520 Asset-backed securities: Student loans (1) 3,325 37 4 3,358 5,659 12 75 5,596 Credit cards 1,565 2 25 1,542 1,377 — 26 1,351 Sub-prime — — — — 289 1 18 272 Other (2) 1,440 7 — 1,447 895 10 — 905 Total asset-backed securities 6,330 46 29 6,347 8,220 23 119 8,124 Non-U.S. debt securities: Mortgage-backed securities 6,664 36 5 6,695 6,506 35 6 6,535 Asset-backed securities 2,942 5 — 2,947 2,513 4 1 2,516 Government securities 10,754 16 49 10,721 5,834 8 6 5,836 Other (3) 6,076 38 6 6,108 5,587 31 5 5,613 Total non-U.S. debt securities 26,436 95 60 26,471 20,440 78 18 20,500 State and political subdivisions 8,929 245 23 9,151 10,233 201 112 10,322 Collateralized mortgage obligations 1,060 3 9 1,054 2,610 18 35 2,593 Other U.S. debt securities 2,563 12 15 2,560 2,481 18 30 2,469 U.S. equity securities 40 8 2 46 39 6 3 42 Non-U.S. equity securities — — — — 3 — — 3 U.S. money-market mutual funds 397 — — 397 409 — — 409 Non-U.S. money-market mutual funds — — — — 16 — — 16 Total $ 56,952 $ 437 $ 268 $ 57,121 $ 62,056 $ 427 $ 485 $ 61,998 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 17,028 $ — $ 143 $ 16,885 $ 17,527 $ 17 $ 58 $ 17,486 Mortgage-backed securities 16,651 22 225 16,448 10,334 20 221 10,133 Total U.S. Treasury and federal agencies 33,679 22 368 33,333 27,861 37 279 27,619 Asset-backed securities: Student loans (1) 3,047 32 9 3,070 2,883 5 30 2,858 Credit cards 798 2 — 800 897 2 — 899 Other 1 — — 1 35 — — 35 Total asset-backed securities 3,846 34 9 3,871 3,815 7 30 3,792 Non-U.S. debt securities: Mortgage-backed securities 939 82 6 1,015 1,150 70 15 1,205 Asset-backed securities 263 1 — 264 531 — — 531 Government securities 474 2 — 476 286 3 — 289 Other 48 — — 48 113 1 — 114 Total non-U.S. debt securities 1,724 85 6 1,803 2,080 74 15 2,139 Collateralized mortgage obligations 1,209 45 6 1,248 1,413 42 11 1,444 Total $ 40,458 $ 186 $ 389 $ 40,255 $ 35,169 $ 160 $ 335 $ 34,994 (1) Primarily composed of securities guaranteed by the federal government with respect to at least 97% of defaulted principal and accrued interest on the underlying loans. (2) As of December 31, 2017 and December 31, 2016 , the fair value of other ABS was primarily composed of $1,447 million and $905 million , respectively, of CLOs. (3) As of December 31, 2017 and December 31, 2016 , the fair value of other non-U.S. debt securities was primarily composed of $3,537 million and $3,769 million , respectively, of covered bonds and $1,885 million and $988 million , as of December 31, 2017 and December 31, 2016 , respectively, of corporate bonds.
Schedule of Gross Pre-tax Unrealized Losses on Investment Securities	The following tables present the aggregate fair values of investment securities that have been in a continuous unrealized loss position for less than 12 months , and those that have been in a continuous unrealized loss position for 12 months or longer, as of the dates indicated: Less than 12 months 12 months or longer Total December 31, 2017 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses (In millions) Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ — $ — $ 67 $ 1 $ 67 $ 1 Mortgage-backed securities 5,161 31 3,341 98 8,502 129 Total U.S. Treasury and federal agencies 5,161 31 3,408 99 8,569 130 Asset-backed securities: Student loans — — 769 4 769 4 Credit cards 1,289 25 — — 1,289 25 Total asset-backed securities 1,289 25 769 4 2,058 29 Non-U.S. debt securities: Mortgage-backed securities 1,059 4 469 1 1,528 5 Government securities 7,629 48 68 1 7,697 49 Other 816 4 289 2 1,105 6 Total non-U.S. debt securities 9,504 56 826 4 10,330 60 State and political subdivisions 734 6 901 17 1,635 23 Collateralized mortgage obligations 399 5 136 4 535 9 Other U.S. debt securities 1,007 8 345 7 1,352 15 U.S. equity securities — — 6 2 6 2 Total $ 18,094 $ 131 $ 6,391 $ 137 $ 24,485 $ 268 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 14,439 $ 109 $ 2,447 $ 34 $ 16,886 $ 143 Mortgage-backed securities 6,785 38 5,988 187 12,773 225 Total U.S. Treasury and federal agencies 21,224 147 8,435 221 29,659 368 Asset-backed securities: Student loans 440 3 423 6 863 9 Total asset-backed securities 440 3 423 6 863 9 Non-U.S. debt securities: Mortgage-backed securities — — 239 6 239 6 Total non-U.S. debt securities — — 239 6 239 6 Collateralized mortgage obligations — — 276 6 276 6 Total $ 21,664 $ 150 $ 9,373 $ 239 $ 31,037 $ 389 Less than 12 months 12 months or longer Total December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses (In millions) Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ 651 $ 8 $ 180 $ 1 $ 831 $ 9 Mortgage-backed securities 7,072 131 1,114 28 8,186 159 Total U.S. Treasury and federal agencies 7,723 139 1,294 29 9,017 168 Asset-backed securities: Student loans 54 — 3,745 75 3,799 75 Credit cards 795 1 494 25 1,289 26 Sub-prime 1 — 252 18 253 18 Other 75 — — — 75 — Total asset-backed securities 925 1 4,491 118 5,416 119 Non-U.S. debt securities: Mortgage-backed securities 442 1 893 5 1,335 6 Asset-backed securities 253 — 276 1 529 1 Government securities 1,314 6 — — 1,314 6 Other 670 4 218 1 888 5 Total non-U.S. debt securities 2,679 11 1,387 7 4,066 18 State and political subdivisions 3,390 102 304 10 3,694 112 Collateralized mortgage obligations 1,259 31 162 4 1,421 35 Other U.S. debt securities 944 24 157 6 1,101 30 U.S. equity securities 8 — 5 3 13 3 Total $ 16,928 $ 308 $ 7,800 $ 177 $ 24,728 $ 485 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 8,891 $ 57 $ 86 $ 1 $ 8,977 $ 58 Mortgage-backed securities 6,838 221 — — 6,838 221 Total U.S. Treasury and federal agencies 15,729 278 86 1 15,815 279 Asset-backed securities: Student loans 705 9 1,235 21 1,940 30 Credit cards 33 — — — 33 — Other 18 — 9 — 27 — Total asset-backed securities 756 9 1,244 21 2,000 30 Non-U.S. debt securities: Mortgage-backed securities 54 2 330 13 384 15 Asset-backed securities 28 — 35 — 63 — Government securities 180 — — — 180 — Total non-U.S. debt securities 262 2 365 13 627 15 Collateralized mortgage obligations 537 4 204 7 741 11 Total $ 17,284 $ 293 $ 1,899 $ 42 $ 19,183 $ 335
Investments Classified by Contractual Maturity Date	The following table presents contractual maturities of debt investment securities by carrying amount as of December 31, 2017 . The maturities of certain ABS, MBS, and CMOs are based on expected principal payments. Actual maturities may differ from these expected maturities since certain borrowers have the right to prepay obligations with or without prepayment penalties. December 31, 2017 Under 1 Year 1 to 5 Years 6 to 10 Years Over 10 Years Total (In millions) Available-for-sale: U.S. Treasury and federal agencies: Direct obligations $ — $ 12 $ 6 $ 205 $ 223 Mortgage-backed securities 96 762 3,123 6,891 10,872 Total U.S. Treasury and federal agencies 96 774 3,129 7,096 11,095 Asset-backed securities: Student loans 289 1,044 685 1,340 3,358 Credit cards — 1,290 252 — 1,542 Other — 350 956 141 1,447 Total asset-backed securities 289 2,684 1,893 1,481 6,347 Non-U.S. debt securities: Mortgage-backed securities 551 4,502 602 1,040 6,695 Asset-backed securities 205 2,185 557 — 2,947 Government securities 2,195 3,201 4,448 877 10,721 Other 1,078 4,235 758 37 6,108 Total non-U.S. debt securities 4,029 14,123 6,365 1,954 26,471 State and political subdivisions 474 2,415 4,724 1,538 9,151 Collateralized mortgage obligations 3 145 170 736 1,054 Other U.S. debt securities 296 1,097 1,107 60 2,560 Total $ 5,187 $ 21,238 $ 17,388 $ 12,865 $ 56,678 Held-to-maturity: U.S. Treasury and federal agencies: Direct obligations $ 1,988 $ 14,968 $ 14 $ 58 $ 17,028 Mortgage-backed securities — 162 1,605 14,884 16,651 Total U.S. Treasury and federal agencies 1,988 15,130 1,619 14,942 33,679 Asset-backed securities: Student loans 35 245 265 2,502 3,047 Credit cards 178 620 — — 798 Other — — — 1 1 Total asset-backed securities 213 865 265 2,503 3,846 Non-U.S. debt securities: Mortgage-backed securities 132 217 45 545 939 Asset-backed securities 26 237 — — 263 Government securities 353 121 — — 474 Other — 48 — — 48 Total non-U.S. debt securities 511 623 45 545 1,724 Collateralized mortgage obligations 8 144 343 714 1,209 Total $ 2,720 $ 16,762 $ 2,272 $ 18,704 $ 40,458
Schedule of Credit-Related Loss Activity Recognized in Earnings	The following tables present gross realized gains and losses from sales of AFS investment securities, and the components of net impairment losses included in net gains and losses related to investment securities for the periods indicated. Years Ended December 31, (In millions) 2017 2016 2015 Gross realized gains from sales of AFS investment securities $ 74 $ 15 $ 57 Gross realized losses from sales of AFS investment securities (113 ) (5 ) (62 ) Net impairment losses: Gross losses from OTTI — (2 ) (1 ) Losses reclassified (from) to other comprehensive income — (1 ) — Net impairment losses (1) — (3 ) (1 ) Gains (losses) related to investment securities, net $ (39 ) $ 7 $ (6 ) (1) Net impairment losses, recognized in our consolidated statement of income, were composed of the following: Impairment associated with expected credit losses $ — $ (1 ) $ — Impairment associated with adverse changes in timing of expected future cash flows — (2 ) (1 ) Net impairment losses $ — $ (3 ) $ (1 ) The following table presents a roll-forward with respect to net impairment losses that have been recognized in income for the periods indicated. Years Ended December 31, (In millions) 2017 2016 2015 Balance, beginning of period $ 66 $ 92 $ 115 Additions: Losses for which OTTI was previously recognized — 2 1 Deductions: Previously recognized losses related to securities sold or matured (2 ) (28 ) (24 ) Balance, end of period $ 64 $ 66 $ 92

Loans and Leases (Tables)

Loans and Leases (Tables)	12 Months Ended
	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Abstract]
Net Loans	The following table presents our recorded investment in loans and leases, by segment, as of the dates indicated: (In millions) December 31, 2017 December 31, 2016 Domestic: Commercial and financial: Loans to investment funds $ 13,618 $ 11,734 Senior secured bank loans 2,923 3,256 Loans to municipalities 2,105 1,352 Other 50 70 Commercial real estate 98 27 Lease financing 267 338 Total domestic 19,061 16,777 Non-U.S.: Commercial and financial: Loans to investment funds 3,213 2,224 Senior secured bank loans 624 252 Lease financing 396 504 Total non-U.S. 4,233 2,980 Total loans and leases 23,294 19,757 Allowance for loan and lease losses (54 ) (53 ) Loans and leases, net of allowance $ 23,240 $ 19,704
Schedule of Components of Leveraged Lease Investments	The components of our net investment in leveraged lease financing, included in the lease financing segment in the preceding table, were as follows as of December 31, 2017 and December 31, 2016: (In millions) 2017 2016 Net rental income receivable $ 808 $ 1,039 Estimated residual values 89 89 Unearned income (234 ) (286 ) Investment in leveraged lease financing 663 842 Less: related deferred income tax liabilities (184 ) (313 ) Net investment in leveraged lease financing $ 479 $ 529
Recorded Investment in Each Class of Total Loans and Leases by Credit Quality Indicator	The following tables present our recorded investment in each class of loans and leases by credit quality indicator as of the dates indicated: December 31, 2017 Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases (In millions) Investment grade (1) $ 17,866 $ 98 $ 663 $ 18,627 Speculative (2) 4,638 — — 4,638 Special mention (3) 29 — — 29 Total $ 22,533 $ 98 $ 663 $ 23,294 December 31, 2016 Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases (In millions) Investment grade (1) $ 14,889 $ 27 $ 842 $ 15,758 Speculative (2) 3,984 — — 3,984 Substandard (4) 15 — — 15 Total $ 18,888 $ 27 $ 842 $ 19,757 (1) Investment-grade loans and leases consist of counterparties with strong credit quality and low expected credit risk and probability of default. Ratings apply to counterparties with a strong capacity to support the timely repayment of any financial commitment. (2) Speculative loans and leases consist of counterparties that face ongoing uncertainties or exposure to business, financial, or economic downturns. However, these counterparties may have financial flexibility or access to financial alternatives, which allow for financial commitments to be met. (3) Special mention loans and leases consist of counterparties with potential weaknesses that, if uncorrected, may result in deterioration of repayment prospects. (4) Substandard loans and leases consist of counterparties with well-defined weakness that jeopardizes repayment with the possibility we will sustain some loss
Schedule of Loans and Leases Receivable by Impairment Methodology	The following table presents our recorded investment in loans and leases, disaggregated based on our impairment methodology, as of the dates indicated: December 31, 2017 December 31, 2016 (In millions) Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases Commercial and Financial Commercial Real Estate Lease Financing Total Loans and Leases Loans and leases (1) : Individually evaluated for impairment $ — $ — $ — $ — $ 15 $ — $ — $ 15 Collectively evaluated for impairment 22,533 98 663 23,294 18,873 27 842 19,742 Total $ 22,533 $ 98 $ 663 $ 23,294 $ 18,888 $ 27 $ 842 $ 19,757 (1) For those portfolios where there are a small number of loans each with a large balance, we review each loan annually for indicators of impairment. For those loans where no such indicators are identified, the loans are collectively evaluated for impairment. As of December 31, 2017 , no loans were individually evaluated for impairment. As of December 31, 2016 , $195 thousand of the allowance for loan and lease loss related to commercial and financial loans were individually evaluated for impairment, and the remainder of the allowance related to commercial and financial loans collectively evaluated for impairment.
Schedule of Activity in the Allowance for Loan Losses	The following table presents activity in the allowance for loan and lease losses for the periods indicated: Years Ended December 31, 2017 2016 2015 (In millions) Total Loans and Leases Total Loans and Leases Total Loans and Leases Allowance for loan and lease losses (1) : Beginning balance $ 53 $ 46 $ 38 Provision for loan and lease losses 2 10 12 Charge-offs (1 ) (3 ) (4 ) Ending balance $ 54 $ 53 $ 46 (1) The provisions and charge-offs for loans and leases were attributable to exposure to senior secured loans to non-investment grade borrowers, purchased in connection with our participation in syndicated loans.

Goodwill and Other Intangible41

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Changes In The Carrying Amount Of Goodwill	The following table presents changes in the carrying amount of goodwill during the periods indicated: (In millions) Investment Servicing Investment Management Total Goodwill: Ending balance December 31, 2015 $ 5,641 $ 30 $ 5,671 Acquisitions (1) — 236 236 Divestitures and other reductions (11 ) — (11 ) Foreign currency translation (80 ) (2 ) (82 ) Ending balance December 31, 2016 $ 5,550 $ 264 $ 5,814 Acquisitions 17 — 17 Divestitures and other reductions (9 ) — (9 ) Foreign currency translation 194 6 200 Ending balance December 31, 2017 $ 5,752 $ 270 $ 6,022 (1) Investment Management includes our acquisition of the GEAM business on July 1, 2016, which is described in Note 1.
Schedule of Finite-Lived Intangible Assets	The following table presents changes in the net carrying amount of other intangible assets during the periods indicated: (In millions) Investment Servicing Investment Management Total Other intangible assets: Ending balance December 31, 2015 $ 1,753 $ 15 $ 1,768 Acquisitions (1) — 217 217 Divestitures (8 ) — (8 ) Amortization (186 ) (21 ) (207 ) Foreign currency translation and other, net (20 ) — (20 ) Ending balance December 31, 2016 $ 1,539 $ 211 $ 1,750 Acquisitions 16 — 16 Divestitures (11 ) — (11 ) Amortization (183 ) (31 ) (214 ) Foreign currency translation and other, net 71 1 72 Ending balance December 31, 2017 $ 1,432 $ 181 $ 1,613 (1) Investment Management includes our acquisition of the GEAM business on July 1, 2016, which is described in Note 1. The following table presents the gross carrying amount, accumulated amortization and net carrying amount of other intangible assets by type as of the dates indicated: December 31, 2017 December 31, 2016 (In millions) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Other intangible assets: Client relationships $ 2,669 $ (1,470 ) $ 1,199 $ 2,620 $ (1,306 ) $ 1,314 Core deposits 686 (320 ) 366 661 (277 ) 384 Other 142 (94 ) 48 132 (80 ) 52 Total $ 3,497 $ (1,884 ) $ 1,613 $ 3,413 $ (1,663 ) $ 1,750
Schedule of Other Intangible Assets, Future Amortization Expense	Expected future amortization expense for other intangible assets recorded as of December 31, 2017 is as follows: (In millions) Future Amortization Years Ending December 31, 2018 $ 191 2019 174 2020 171 2021 166 2022 165

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Other Assets [Abstract]
Components of Other Assets	The following table presents the components of other assets as of the dates indicated: (In millions) December 31, 2017 December 31, 2016 Receivable - securities lending (1) $ 19,404 $ 21,204 Derivative instruments, net 4,013 7,321 Bank-owned life insurance 3,242 3,158 Investments in joint ventures and other unconsolidated entities 2,259 2,363 Collateral, net 473 2,236 Prepaid expenses 364 333 Accounts receivable 348 886 Receivable for securities settlement 188 40 Deposits with clearing organizations 120 132 Deferred tax assets, net of valuation allowance (2) 113 210 Income taxes receivable 97 106 Other (3) 397 339 Total $ 31,018 $ 38,328 (1) Refer to Note 11 for further information on the impact of collateral on our financial statement presentation of securities borrowing transactions. (2) Deferred tax assets and liabilities recorded in our consolidated statement of condition are netted within the same tax jurisdiction. Gross deferred tax assets and liabilities are presented in Note 22 . (3) In 2017, includes amounts held in escrow accounts at third parties related to the negotiated settlements in the transition management legal matter presented in Note 13 .

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Short-term Debt	The following table presents information about these U.S. government securities and the carrying value of the related repurchase agreements, including accrued interest, as of December 31, 2017 . The table excludes repurchase agreements collateralized by securities purchased under resale agreements and collateralized by trading account assets. U.S. Government Securities Sold Repurchase Agreements (1) (In millions) Amortized Cost Fair Value Amortized Cost Overnight maturity $ 2,928 $ 2,899 $ 2,842 (1) Collateralized by investment securities. The following tables present information with respect to the amounts outstanding and weighted-average interest rates of the primary components of our short-term borrowings as of and for the years ended December 31 : Securities Sold Under Repurchase Agreements Federal Funds Purchased Tax-Exempt Investment Program (Dollars in millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Balance as of December 31 $ 2,842 $ 4,400 $ 4,499 $ — $ — $ 6 $ 1,078 $ 1,158 $ 1,748 Maximum outstanding as of any month-end 4,302 5,572 10,977 — 29 29 1,158 1,726 1,865 Average outstanding during the year 3,683 4,113 8,875 1 31 21 1,127 1,512 1,807 Weighted-average interest rate as of year-end .03 % .04 % .02 % .00 % .00 % .03 % 1.45 % .67 % .03 % Weighted-average interest rate during the year .05 .02 .01 .00 .17 .01 .79 .36 .06

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Long-term Debt, Unclassified [Abstract]
Schedule of Long-term Debt	(Dollars in millions) As of December 31, Issuance Date Maturity Date Coupon Rate Seniority Interest Due Dates 2017 2016 Parent Company And Non-Banking Subsidiary Issuances August 18, 2015 August 18, 2025 3.55 % Senior notes 2/18; 8/18 (1) 1,287 1,293 August 18, 2015 August 18, 2020 2.55 % Senior notes 2/18; 8/18 (1) 1,184 1,192 November 19, 2013 November 20, 2023 3.7 % Senior notes 5/20; 11/20 (1) 1,021 1,033 December 15, 2014 December 16, 2024 3.3 % Senior notes 6/16; 12/16 (1) 993 999 May 15, 2013 May 15, 2023 (2) 3.1 % Subordinated notes 5/15; 11/15 (1) 981 987 April 30, 2007 June 15, 2047 Floating-rate Junior subordinated debentures 3/15; 6/15; 9/15; 12/15 793 793 May 15, 2017 May 15, 2023 2.653 % Fixed to Floating Rate Senior notes 5/15; 11/15 (1) 740 — March 7, 2011 March 7, 2021 4.375 % Senior notes 3/7; 9/7 (1) 734 738 May 19, 2016 May 19, 2021 1.95 % Senior notes 5/19; 11/19 (1) 724 726 May 19, 2016 May 19, 2026 2.65 % Senior notes 5/19; 11/19 (1) 706 704 February 11, 2011 March 15, 2018 (3) 4.956 % Junior subordinated debentures 3/15; 9/15 502 511 August 18, 2015 August 18, 2020 Floating-rate Senior notes 2/18; 5/18; 8/18; 11/18 499 499 May 15, 2013 May 15, 2018 1.35 % Senior notes 5/15; 11/15 499 497 May 15, 1998 May 15, 2028 Floating-rate Junior subordinated debentures 2/15; 5/15; 8/15; 11/15 150 150 June 21, 1996 June 15, 2026 (4) 7.35 % Senior notes 6/15; 12/15 150 150 April 30, 2007 April 30, 2017 5.375 % Senior notes 4/30; 10/30 — 450 Parent Company Long-term capital leases 250 293 State Street Bank issuances September 24, 2003 October 15, 2018 (2) 5.25 % Subordinated notes 4/15; 10/15 407 415 Total long-term debt $ 11,620 $ 11,430 (1) We have entered into interest-rate swap agreements, recorded as fair value hedges, to modify our interest expense on these senior and subordinated notes from a fixed rate to a floating rate. As of December 31, 2017 and December 31, 2016 , the carrying value of long-term debt associated with these fair value hedges decreased $87 million and $15 million , respectively. Refer to Note 10 for additional information about fair value hedges. (2) The subordinated notes qualify for inclusion in tier 2 regulatory capital under current federal regulatory capital guidelines. (3) We do not have the right to redeem the debenture prior to maturity other than upon the occurrence of specified events. Such redemption is subject to federal regulatory approval. The junior subordinated debentures qualify for inclusion in tier 2 regulatory capital under current federal regulatory capital guidelines. (4) We may not redeem notes prior to their maturity.

Derivative Financial Instrume45

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Derivatives	The table below summarizes the maturities and the paid fixed interest rates for the hedged senior and subordinated notes: December 31, 2017 Maturity Paid Fixed Interest Rate Senior Notes 2020 2.55% 2021 4.38 2021 1.95 2022 2.65 2023 3.70 2024 3.30 2025 3.55 2026 2.65 Subordinated Notes 2023 3.10
Schedule of Outstanding Hedges: (Notional Amount)	The following table presents the aggregate contractual, or notional, amounts of derivative financial instruments entered into in connection with our trading and asset-and-liability management activities as of the dates indicated: (In millions) December 31, December 31, Derivatives not designated as hedging instruments: Interest-rate contracts: Futures 2,392 13,455 Foreign exchange contracts: Forward, swap and spot 1,679,976 1,414,765 Options purchased 350 337 Options written 302 202 Futures 50 — Commodity and equity contracts: Commodity (1) 16 — Equity (1) 50 — Other: Stable value contracts 26,653 27,182 Deferred value awards (2)(3) 473 409 Derivatives designated as hedging instruments: Interest-rate contracts: Swap agreements 11,047 10,169 Foreign exchange contracts: Forward and swap 28,913 8,564 (1) Primarily composed of positions held by a consolidated sponsored investment fund, more fully described in Note 14 . (2) Represents grants of deferred value awards to employees; refer to discussion in this note under "Derivatives Not Designated as Hedging Instruments." (3) Amount as of December 31, 2016 reflects $249 million related to the acceleration of expense associated with certain cash settled deferred incentive compensation awards.
Notional Amount of Interest Rate Swap Agreements Designated as Fair Value and Cash Flow Hedges	The following tables present the aggregate notional amounts of these interest rate contracts and the related assets or liabilities being hedged as of the dates indicated: December 31, 2017 (In millions) Fair Value Hedges Cash (1) Total Investment securities available for sale $ 1,254 $ — $ 1,254 Long-term debt (2) 8,493 — 8,493 Floating rate loans — 1,300 1,300 Total $ 9,747 $ 1,300 $ 11,047 December 31, 2016 (In millions) Fair Value Hedges Cash Total Investment securities available for sale $ 1,444 $ — $ 1,444 Long-term debt (2) 8,725 — 8,725 Floating rate loans — — — Total $ 10,169 $ — $ 10,169 (1) In 2017 , we entered into interest-rate contracts designated as cash flow hedges for floating rate loans. (2) As of December 31, 2017 and December 31, 2016 , these fair value hedges decreased the carrying value of long-term debt presented in our consolidated statement of condition by $87 million and $15 million , respectively.
Contractual and Weighted-Average Interest Rates, Which Include the Effects of Hedges Related to Financial Instruments	The following table presents the contractual and weighted-average interest rates for long-term debt, which include the effects of the fair value hedges presented in the table above, for the periods indicated: Years Ended December 31, 2017 2016 Contractual Rate Contractual Rate Long-term debt 3.34 % 2.66 % 3.40 % 2.29 %
Schedule of the Fair Values of Derivative Financial Instruments	The following tables present the fair value of derivative financial instruments, excluding the impact of master netting agreements, recorded in our consolidated statement of condition as of the dates indicated. The impact of master netting agreements is provided in Note 11 to the consolidated financial statements in this Form 10-K. Derivative Assets (1) Fair Value (In millions) December 31, 2017 December 31, 2016 Derivatives not designated as hedging instruments: Foreign exchange contracts $ 11,477 $ 15,982 Other derivative contracts 1 — Total $ 11,478 $ 15,982 Derivatives designated as hedging instruments: Foreign exchange contracts $ 120 $ 502 Interest-rate contracts 8 68 Total $ 128 $ 570 (1) Derivative assets are included within other assets in our consolidated statement of condition. Derivative Liabilities (1) Fair Value (In millions) December 31, 2017 December 31, 2016 Derivatives not designated as hedging instruments: Foreign exchange contracts $ 11,361 $ 15,881 Other derivative contracts 284 380 Total $ 11,645 $ 16,261 Derivatives designated as hedging instruments: Foreign exchange contracts $ 107 $ 75 Interest-rate contracts 100 348 Total $ 207 $ 423 (1) Derivative liabilities are included within other liabilities in our consolidated statement of condition.
Impact of Derivatives on Consolidated Statement of Income	The following tables present the impact of our use of derivative financial instruments on our consolidated statement of income for the periods indicated: Location of Gain (Loss) on Derivative in Consolidated Statement of Income Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Years Ended December 31, (In millions) 2017 2016 2015 Derivatives not designated as hedging instruments: Foreign exchange contracts Trading services revenue $ 632 $ 662 $ 686 Interest-rate contracts Processing fees and other revenue — 1 — Foreign exchange contracts Processing fees and other revenue (23 ) — — Interest-rate contracts Trading services revenue 8 (7 ) (2 ) Credit derivative contracts Trading services revenue — (1 ) (1 ) Other derivative contracts Trading services revenue — (2 ) 8 Other derivative contracts Compensation and employee benefits (143 ) (448 ) (149 ) Total $ 474 $ 205 $ 542
Schedule of Differences Between the Gains (Losses) on the Derivative and the Gains (Losses) on the Hedged Item	Location of Gain (Loss) on Derivative in Consolidated Statement of Income Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Hedged Item in Fair Value Hedging Relationship Location of Gain (Loss) on Hedged Item in Consolidated Statement of Income Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income Years Ended December 31, Years Ended December 31, (In millions) 2017 2016 2015 2017 2016 2015 Derivatives designated as fair value hedges: Foreign exchange contracts Processing fees and $ 18 $ (6 ) $ (101 ) Investment securities Processing fees and $ (18 ) $ 6 $ 101 Foreign exchange contracts Processing fees and other revenue 626 221 (241 ) FX deposit Processing fees and other revenue (626 ) (221 ) 241 Interest-rate contracts Processing fees and other revenue 39 43 16 Available-for-sale securities Processing fees and other revenue (1) (37 ) (40 ) (17 ) Interest-rate contracts Processing fees and (38 ) (98 ) 61 Long-term debt Processing fees and 39 100 (54 ) Total $ 645 $ 160 $ (265 ) $ (642 ) $ (155 ) $ 271 (1) In 2017 , 2016 and 2015 , $22 million , $23 million and $12 million , respectively, of net unrealized gains on AFS investment securities designated in fair value hedges were recognized in OCI. Differences between the gains (losses) on the derivative and the gains (losses) on the hedged item, excluding any amounts recorded in NII, represent hedge ineffectiveness. Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income Location of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income Location of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income Years Ended December 31, Years Ended December 31, Years Ended December 31, (In millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Derivatives designated as cash flow hedges: Interest-rate contracts $ (14 ) $ — $ — Net interest income $ — $ — $ (4 ) Net interest income $ 2 $ — $ — Foreign exchange contracts (104 ) (39 ) 55 Net interest income — — — Net interest income 24 24 10 Total $ (118 ) $ (39 ) $ 55 $ — $ — $ (4 ) $ 26 $ 24 $ 10 Derivatives designated as net investment hedges: Foreign exchange contracts $ (160 ) $ 109 $ — Gains (Losses) related to investment securities, net $ — $ — $ — Gains (Losses) related to investment securities, net $ — $ — $ — Total $ (160 ) $ 109 $ — $ — $ — $ — $ — $ — $ —

Offsetting Arrangements (Tables

Offsetting Arrangements (Tables)	12 Months Ended
	Dec. 31, 2017
Offsetting [Abstract]
Offsetting Assets	The following tables present information about the offsetting of assets related to derivative contracts and secured financing transactions, as of the dates indicated: Assets: December 31, 2017 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Assets (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Assets Presented in Statement of Condition Cash and Securities Received (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 11,597 $ (5,548 ) $ 6,049 $ 6,049 Interest-rate contracts (6) 8 — 8 8 Other derivative contracts 1 — 1 1 Cash collateral and securities netting NA (2,045 ) (2,045 ) $ (124 ) (2,169 ) Total derivatives 11,606 (7,593 ) 4,013 (124 ) 3,889 Other financial instruments: Resale agreements and securities borrowing (7) 70,079 (47,434 ) 22,645 (22,645 ) — Total derivatives and other financial instruments $ 81,685 $ (55,027 ) $ 26,658 $ (22,769 ) $ 3,889 Assets: December 31, 2016 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Assets (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Assets Presented in Statement of Condition Cash and Securities Received (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 16,484 $ (8,257 ) $ 8,227 $ 8,227 Interest-rate contracts 68 (68 ) — — Cash collateral and securities netting NA (906 ) (906 ) $ (247 ) (1,153 ) Total derivatives 16,552 (9,231 ) 7,321 (247 ) 7,074 Other financial instruments: Resale agreements and securities borrowing (7) 58,677 (35,517 ) 23,160 (22,939 ) 221 Total derivatives and other financial instruments $ 75,229 $ (44,748 ) $ 30,481 $ (23,186 ) $ 7,295 (1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement. (2) Derivative amounts are carried at fair value and securities financing amounts are carried at amortized cost, except for securities collateral which is also carried at fair value. Refer to Note 1 and Note 2 for additional information about the measurement basis of these instruments. (3) Amounts subject to netting arrangements which have been determined to be legally enforceable and eligible for netting in the consolidated statement of condition. (4) Includes securities in connection with our securities borrowing transactions. (5) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements. (6) Variation margin payments presented as settlements rather than collateral. (7) Included in the $22,645 million as of December 31, 2017 were $3,241 million of resale agreements and $19,404 million of collateral provided related to securities borrowing. Included in the $23,160 million as of December 31, 2016 were $1,956 million of resale agreements and $21,204 million of collateral provided related to securities borrowing. Resale agreements and collateral provided related to securities borrowing were recorded in securities purchased under resale agreements and other assets, respectively, in our consolidated statement of condition. Refer to Note 12 for additional information with respect to principal securities finance transactions. NA Not applicable
Offsetting Liabilities	The following tables present information about the offsetting of liabilities related to derivative contracts and secured financing transactions, as of the dates indicated: Liabilities: December 31, 2017 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Liabilities (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Liabilities Presented in Statement of Condition Cash and Securities Provided (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 11,467 $ (5,548 ) $ 5,919 $ 5,919 Interest-rate contracts (6) 100 — 100 100 Other derivative contracts 285 — 285 285 Cash collateral and securities netting NA (422 ) (422 ) $ (450 ) (872 ) Total derivatives 11,852 (5,970 ) 5,882 (450 ) 5,432 Other financial instruments: Repurchase agreements and securities lending (7) 54,127 (47,434 ) 6,693 (4,299 ) 2,394 Total derivatives and other financial instruments $ 65,979 $ (53,404 ) $ 12,575 $ (4,749 ) $ 7,826 Liabilities: December 31, 2016 Gross Amounts Not Offset in Statement of Condition (In millions) Gross Amounts of Recognized Liabilities (1)(2) Gross Amounts Offset in Statement of Condition (3) Net Amounts of Liabilities Presented in Statement of Condition Cash and Securities Provided (4) Net Amount (5) Derivatives: Foreign exchange contracts $ 15,956 $ (8,253 ) $ 7,703 $ 7,703 Interest-rate contracts 348 (73 ) 275 275 Other derivative contracts 380 — 380 380 Cash collateral and securities netting NA (2,356 ) (2,356 ) $ (180 ) (2,536 ) Total derivatives 16,684 (10,682 ) 6,002 (180 ) 5,822 Other financial instruments: Resale agreements and securities lending (7) 44,933 (35,517 ) 9,416 (7,059 ) 2,357 Total derivatives and other financial instruments $ 61,617 $ (46,199 ) $ 15,418 $ (7,239 ) $ 8,179 (1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement. (2) Derivative amounts are carried at fair value and securities financing amounts are carried at amortized cost, except for securities collateral which is also carried at fair value. Refer to Note 1 and Note 2 for additional information about the measurement basis of these instruments. (3) Amounts subject to netting arrangements which have been determined to be legally enforceable and eligible for netting in the consolidated statement of condition. (4) Includes securities provided in connection with our securities lending transactions. (5) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements. (6) Variation margin payments presented as settlements rather than collateral. (7) Included in the $6,693 million as of December 31, 2017 were $2,842 million of repurchase agreements and $3,851 million of collateral received related to securities lending. Included in the $9,416 million as of December 31, 2016 were $4,400 million of repurchase agreements and $5,016 million of collateral received related to securities lending. Repurchase agreements and collateral received related to securities lending were recorded in securities sold under repurchase agreements and accrued expenses and other liabilit ies, respectively, in our consolidated statement of condition. Refer to Note 12 for additional information with respect to principal securities finance transactions . NA Not applicable
Securities Sold and Securities Loaned Under Repurchase Agreements	The following tables summarize our repurchase agreements and securities lending transactions by category of collateral pledged and remaining maturity of these agreements as of the periods indicated: Remaining Contractual Maturity of the Agreements As of December 31, 2017 (In millions) Overnight and Continuous Up to 30 days 30 – 90 days Total Repurchase agreements: U.S. Treasury and agency securities $ 43,072 $ — $ — $ 43,072 Total 43,072 — — 43,072 Securities lending transactions: Corporate debt securities 35 — — 35 Equity securities 11,020 — — 11,020 Non-U.S. sovereign debt — — — — Total 11,055 — — 11,055 Gross amount of recognized liabilities for repurchase agreements and securities lending $ 54,127 $ — $ — $ 54,127 Remaining Contractual Maturity of the Agreements As of December 31, 2016 (In millions) Overnight and Continuous Up to 30 days 30 – 90 days Total Repurchase agreements: U.S. Treasury and agency securities $ 35,509 $ — $ — $ 35,509 Total 35,509 — — 35,509 Securities lending transactions: Corporate debt securities 53 — — 53 Equity securities 8,337 — 1,034 9,371 Total 8,390 — 1,034 9,424 Gross amount of recognized liabilities for repurchase agreements and securities lending $ 43,899 $ — $ 1,034 $ 44,933

Commitments and Guarantees (Tab

Commitments and Guarantees (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Guarantor Obligations	The following table presents the aggregate gross contractual amounts of our off-balance sheet commitments and off-balance sheet guarantees as of the dates indicated. (In millions) December 31, 2017 December 31, 2016 Commitments: Unfunded credit facilities $ 26,488 $ 26,993 Guarantees (1) : Indemnified securities financing $ 381,817 $ 360,452 Stable value protection 26,653 27,182 Standby letters of credit 3,158 3,459 (1) The potential losses associated with these guarantees equal the gross contractual amounts and do not consider the value of any collateral or reflect any participations to independent third parties.
Schedule of Repurchase Agreements	The following table summarizes the aggregate fair values of indemnified securities financing and related collateral, as well as collateral invested in indemnified repurchase agreements, as of the dates indicated: (In millions) December 31, 2017 December 31, 2016 Fair value of indemnified securities financing $ 381,817 $ 360,452 Fair value of cash and securities held by us, as agent, as collateral for indemnified securities financing 400,828 377,919 Fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements 61,270 60,003 Fair value of cash and securities held by us or our agents as collateral for investments in indemnified repurchase agreements 65,272 63,959

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Preferred Shares	The following table summarizes selected terms of each of the series of the preferred stock issued and outstanding as of December 31, 2017 : Issuance Date Depositary Shares Issued Ownership Interest Per Depositary Share Liquidation Preference Per Share Liquidation Preference Per Depositary Share Net Proceeds of Offering (In millions) Redemption Date (1) Preferred Stock (2) : Series C August 2012 20,000,000 1/4,000th $ 100,000 $ 25 $ 488 September 15, 2017 Series D February 2014 30,000,000 1/4,000th 100,000 25 742 March 15, 2024 Series E November 2014 30,000,000 1/4,000th 100,000 25 728 December 15, 2019 Series F May 2015 750,000 1/100th 100,000 1,000 742 September 15, 2020 Series G April 2016 20,000,000 1/4,000th 100,000 25 493 March 15, 2026 (1) On the redemption date, or any dividend declaration date thereafter, the preferred stock and corresponding depositary shares may be redeemed by us, in whole or in part, at the liquidation price per share and liquidation price per depositary share plus any declared and unpaid dividends, without accumulation of any undeclared dividends. (2) The preferred stock and corresponding depositary shares may be redeemed at our option in whole, but not in part, prior to the redemption date upon the occurrence of a regulatory capital treatment event, as defined in the certificate of designation, at a redemption price equal to the liquidation price per share and liquidation price per depositary share plus any declared and unpaid dividends, without accumulation of any undeclared dividends.
Dividends Declared	The table below presents the dividends declared on common stock for the periods indicated: Years Ended December 31, 2017 2016 Dividends Declared per Share Total (In millions) Dividends Declared per Share Total (In millions) Common Stock $ 1.60 $ 596 $ 1.44 $ 559 The following table present the dividends declared for each of the series of preferred stock issued and outstanding for the periods indicated: Years Ended December 31, 2017 2016 Dividends Declared per Share Dividends Declared per Depositary Share Total (In millions) Dividends Declared per Share Dividends Declared per Depositary Share Total (In millions) Preferred Stock: Series C $ 5,250 $ 1.32 $ 26 $ 5,250 $ 1.32 $ 26 Series D 5,900 1.48 44 5,900 1.48 44 Series E 6,000 1.52 45 6,000 1.52 45 Series F 5,250 52.50 40 5,250 52.50 40 Series G 5,352 1.32 27 3,626 0.90 18 Total $ 182 $ 173
Stock Repurchase Program	The table below presents the activity under both the 2017 Program and 2016 Program during the year ended December 31, 2017: Shares Acquired Average Cost per Share Total Acquired 2016 Program (1) 9.4 $ 79.93 $ 750 2017 Program 7.4 94.54 700 Total 16.8 $ 86.37 $ 1,450 (1) Includes $158 million relating to shares acquired in exchange for BFDS stock during the first quarter of 2017. Additional information about the exchange is provided in Note 1 to the consolidated financial statements included in this Form 10-K.
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents the after-tax components of AOCI as of the dates indicated: December 31 (In millions) 2017 2016 2015 Net unrealized gains (losses) on cash flow hedges $ (56 ) $ 229 $ 293 Net unrealized gains (losses) on available-for-sale securities portfolio 148 (225 ) 9 Net unrealized gains (losses) related to reclassified available-for-sale securities 19 25 (28 ) Net unrealized gains (losses) on available-for-sale securities 167 (200 ) (19 ) Net unrealized losses on available-for-sale securities designated in fair value hedges (64 ) (86 ) (109 ) Net unrealized gains (losses) on hedges of net investments in non-U.S. subsidiaries (65 ) 95 (14 ) Other-than-temporary impairment on held-to-maturity securities related to factors other than credit (6 ) (9 ) (16 ) Net unrealized losses on retirement plans (170 ) (194 ) (183 ) Foreign currency translation (815 ) (1,875 ) (1,394 ) Total $ (1,009 ) $ (2,040 ) $ (1,442 ) The following table presents changes in AOCI by component, net of related taxes, for the periods indicated: (In millions) Net Unrealized Gains (Losses) on Cash Flow Hedges Net Unrealized Gains (Losses) on Available-for-Sale Securities Net Unrealized Gains (Losses) on Hedges of Net Investments in Non-U.S. Subsidiaries Other-Than-Temporary Impairment on Held-to-Maturity Securities Net Unrealized Losses on Retirement Plans Foreign Currency Translation Total Balance as of December 31, 2015 $ 293 $ (128 ) $ (14 ) $ (16 ) $ (183 ) $ (1,394 ) $ (1,442 ) Other comprehensive income (loss) before reclassifications (64 ) (164 ) 109 8 — (478 ) (589 ) Amounts reclassified into (out of) earnings — 6 — (1 ) (11 ) (3 ) (9 ) Other comprehensive income (loss) (64 ) (158 ) 109 7 (11 ) (481 ) (598 ) Balance as of December 31, 2016 $ 229 $ (286 ) $ 95 $ (9 ) $ (194 ) $ (1,875 ) $ (2,040 ) Other comprehensive income (loss) before reclassifications (285 ) 412 (160 ) 3 — 1,059 1,029 Amounts reclassified into (out of) earnings — (23 ) — — 24 1 2 Other comprehensive income (loss) (285 ) 389 (160 ) 3 24 1,060 1,031 Balance as of December 31, 2017 $ (56 ) $ 103 $ (65 ) $ (6 ) $ (170 ) $ (815 ) $ (1,009 )
Schedule of Reclassifications Out of AOCI	The following table presents after-tax reclassifications into earnings for the periods indicated: Years Ended December 31, 2017 2016 (In millions) Amounts Reclassified into (out of) Earnings Affected Line Item in Consolidated Statement of Income Available-for-sale securities: Net realized gains (losses) from sales of available-for-sale securities, net of related taxes of $16 and ($4), respectively $ (23 ) $ 6 Net gains (losses) from sales of available-for-sale securities Held-to-maturity securities: Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes of $0 and $1, respectively — (1 ) Losses reclassified (from) to other comprehensive income Retirement plans: Amortization of actuarial losses, net of related taxes of ($8) and ($1), respectively 24 (11 ) Compensation and employee benefits expenses Foreign currency translation: Sales of non-U.S. entities, net of related taxes of $0 and ($2), respectively 1 (3 ) Processing fees and other revenue Total reclassifications (out of) into AOCI $ 2 $ (9 )

Regulatory Capital (Tables)

Regulatory Capital (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Schedule of Regulatory Capital	The following table presents the regulatory capital structure, total risk-weighted assets, related regulatory capital ratios and the minimum required regulatory capital ratios for State Street and State Street Bank as of the dates indicated. As a result of changes in the methodologies used to calculate our regulatory capital ratios from period to period as the provisions of the Basel III final rule are phased in, the ratios presented in the table for each period-end are not directly comparable. Refer to the footnotes following the table. State Street State Street Bank (In millions) Basel III Advanced Approaches December 31, 2017 (1) Basel III Standardized Approach December 31, 2017 (2) Basel III Advanced Approaches December 31, 2016 (1) Basel III Standardized Approach December 31, 2016 (2) Basel III Advanced Approaches December 31, 2017 (1) Basel III Standardized Approach December 31, 2017 (2) Basel III Advanced Approaches December 31, 2016 (1) Basel III Standardized Approach December 31, 2016 (2) Common shareholders' equity: Common stock and related surplus $ 10,302 $ 10,302 $ 10,286 $ 10,286 $ 11,612 $ 11,612 $ 11,376 $ 11,376 Retained earnings 18,856 18,856 17,459 17,459 12,312 12,312 12,285 12,285 Accumulated other comprehensive income (loss) (972 ) (972 ) (1,936 ) (1,936 ) (809 ) (809 ) (1,648 ) (1,648 ) Treasury stock, at cost (9,029 ) (9,029 ) (7,682 ) (7,682 ) — — — — Total 19,157 19,157 18,127 18,127 23,115 23,115 22,013 22,013 Regulatory capital adjustments: Goodwill and other intangible assets, net of associated deferred tax liabilities (3) (6,877 ) (6,877 ) (6,348 ) (6,348 ) (6,579 ) (6,579 ) (6,060 ) (6,060 ) Other adjustments (76 ) (76 ) (155 ) (155 ) (5 ) (5 ) (148 ) (148 ) Common equity tier 1 capital 12,204 12,204 11,624 11,624 16,531 16,531 15,805 15,805 Preferred stock 3,196 3,196 3,196 3,196 — — — — Trust preferred capital securities subject to phase-out from tier 1 capital — — — — — — — — Other adjustments (18 ) (18 ) (103 ) (103 ) — — — — Tier 1 capital 15,382 15,382 14,717 14,717 16,531 16,531 15,805 15,805 Qualifying subordinated long-term debt 980 980 1,172 1,172 983 983 1,179 1,179 Trust preferred capital securities phased out of tier 1 capital — — — — — — — — ALLL and other 4 72 19 77 — 72 15 77 Other adjustments 1 1 1 1 — — — — Total capital $ 16,367 $ 16,435 $ 15,909 $ 15,967 $ 17,514 $ 17,586 $ 16,999 $ 17,061 Risk-weighted assets: Credit risk $ 49,976 $ 101,349 $ 50,900 $ 98,125 $ 47,448 $ 98,433 $ 47,383 $ 94,413 Operational risk (4) 45,822 NA 44,579 NA 45,295 NA 44,043 NA Market risk (5) 3,358 1,334 3,822 1,751 3,375 1,334 3,822 1,751 Total risk-weighted assets $ 99,156 $ 102,683 $ 99,301 $ 99,876 $ 96,118 $ 99,767 $ 95,248 $ 96,164 Adjusted quarterly average assets $ 209,328 $ 209,328 $ 226,310 $ 226,310 $ 206,070 $ 206,070 $ 222,584 $ 222,584 Capital Ratios: 2017 Minimum Requirements Including Capital Conservation Buffer and G-SIB Surcharge (6) 2016 Minimum Requirements Including Capital Conservation Buffer and G-SIB Surcharge (7) Common equity tier 1 capital 6.5 % 5.5 % 12.3 % 11.9 % 11.7 % 11.6 % 17.2 % 16.6 % 16.6 % 16.4 % Tier 1 capital 8.0 7.0 15.5 15.0 14.8 14.7 17.2 16.6 16.6 16.4 Total capital 10.0 9.0 16.5 16.0 16.0 16.0 18.2 17.6 17.8 17.7 Tier 1 leverage 4.0 4.0 7.3 7.3 6.5 6.5 8.0 8.0 7.1 7.1 (1) CET1 capital, tier 1 capital and total capital ratios as of December 31, 2017 and December 31, 2016 were calculated in conformity with the advanced approaches provisions of the Basel III final rule. Tier 1 leverage ratio as of December 31, 2017 and December 31, 2016 were calculated in conformity with the Basel III final rule. (2) CET1 capital, tier 1 capital and total capital ratios as of December 31, 2017 and December 31, 2016 were calculated in conformity with the standardized approach provisions of the Basel III final rule. Tier 1 leverage ratio as of December 31, 2017 and December 31, 2016 were calculated in conformity with the Basel III final rule. (3) Amounts for State Street and State Street Bank as of December 31, 2017 consisted of goodwill, net of associated deferred tax liabilities, and 80% of other intangible assets, net of associated deferred tax liabilities. Amounts for State Street and State Street Bank as of December 31, 2016 consisted of goodwill, net of deferred tax liabilities and 60% of other intangible assets, net of associated deferred tax liabilities. Intangible assets, net of associated deferred tax liabilities is phased in as a deduction from capital, in conformity with the Basel III final rule. (4) Under the current advanced approaches rules and regulatory guidance concerning operational risk models, RWA attributable to operational risk can vary substantially from period-to-period, without direct correlation to the effects of a particular loss event on our results of operations and financial condition and impacting dates and periods that may differ from the dates and periods as of and during which the loss event is reflected in our financial statements, with the timing and categorization dependent on the processes for model updates and, if applicable, model revalidation and regulatory review and related supervisory processes. An individual loss event can have a significant effect on the output of our operational risk RWA under the advanced approaches depending on the severity of the loss event and its categorization among the seven Basel-defined UOMs. (5) Market risk risk-weighted assets reported in conformity with the Basel III advanced approaches included a CVA which reflected the risk of potential fair value adjustments for credit risk reflected in our valuation of over-the-counter derivative contracts. The CVA was not provided for in the final market risk capital rule; however, it was required by the advanced approaches provisions of the Basel III final rule. We used a simple CVA approach in conformity with the Basel III advanced approaches. (6) Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of December 31, 2017 . (7) Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of December 31, 2016 . NA Not applicable

Net Interest Income (Tables)

Net Interest Income (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Components of Interest Revenue and Interest Expense	The following table presents the components of interest income and interest expense, and related NII, for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Interest income: Deposits with banks $ 180 $ 126 $ 208 Investment securities: U.S. Treasury and federal agencies 854 821 735 State and political subdivisions 226 224 227 Other investments 658 756 934 Securities purchased under resale agreements 264 146 62 Loans and leases 504 378 311 Other interest-earning assets 222 61 11 Total interest income 2,908 2,512 2,488 Interest expense: Deposits 163 85 97 Securities sold under repurchase agreements 2 1 — Short-term borrowings 10 7 7 Long-term debt 308 260 250 Other interest-bearing liabilities 121 75 46 Total interest expense 604 428 400 Net interest income $ 2,304 $ 2,084 $ 2,088

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Options and Stock Appreciation Rights	The following table presents information about the Plans as of December 31, 2017 , and related activity during the years indicated: Shares (In thousands) Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (In years) Total Intrinsic Value (In millions) Stock Appreciation Rights: Outstanding as of December 31, 2015 1,206 $ 76.29 Exercised (227 ) 70.59 Forfeited or expired (24 ) 81.71 Outstanding as of December 31, 2016 955 77.52 Exercised (595 ) 81.71 Forfeited or expired (360 ) 70.59 Outstanding and exercisable as of December 31, 2017 (1) — $ — 0 $ — (1) There were no shares subject to stock options and no stock appreciation rights.
Schedule of Deferred Stock Awards	Shares (In thousands) Weighted-Average Grant Date Fair Value Deferred Stock Awards: Outstanding as of December 31, 2015 8,736 $ 61.59 Granted 4,336 52.49 Vested (4,897 ) 56.18 Forfeited (361 ) 60.12 Outstanding as of December 31, 2016 7,814 60.01 Granted 2,977 76.38 Vested (3,686 ) 62.88 Forfeited (257 ) 63.56 Outstanding as of December 31, 2017 6,848 $ 65.44
Schedule of Performance Awards	Shares (In thousands) Weighted-Average Grant Date Fair Value Performance Awards: Outstanding as of December 31, 2015 1,165 $ 60.45 Granted 506 50.81 Forfeited — — Paid out (424 ) 49.27 Outstanding as of December 31, 2016 1,247 60.37 Granted 534 76.27 Forfeited — — Paid out (233 ) 58.91 Outstanding as of December 31, 2017 1,548 $ 66.09

Occupancy Expense and Informa52

Occupancy Expense and Information Systems and Communications Expense (Tables)	12 Months Ended
	Dec. 31, 2017
Occupancy Expense and Information Systems and Communications Expense [Abstract]
Summary of Future Minimum Lease Payments Under Non Cancelable Capital and Operating Leases	The following table presents a summary of future minimum lease payments under non-cancelable capital and operating leases as of December 31, 2017 . Aggregate future minimum rental commitments have been reduced by aggregate sublease rental commitments of $41 million for capital leases and $19 million for operating leases. (In millions) Capital Leases Operating Leases Total 2018 $ 53 $ 197 $ 250 2019 45 175 220 2020 45 154 199 2021 45 144 189 2022 45 125 170 Thereafter 34 336 370 Total minimum lease payments 267 $ 1,131 $ 1,398 Less amount representing interest payments (56 ) Present value of minimum lease payments $ 211

Expenses (Tables)

Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Other Expenses [Abstract]
Schedule of Expenses	The following table presents the components of other expenses for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Insurance $ 118 $ 93 $ 126 Regulatory fees and assessments 106 82 115 Bank operations 80 62 105 Sales advertising public relations 67 52 65 Litigation (15 ) 50 422 Other 233 245 185 Total other expenses $ 589 $ 584 $ 1,018
Restructuring and Related Costs	The following table presents aggregate restructuring activity for the periods indicated: (In millions) Employee Real Estate Asset and Other Write-offs Total Accrual Balance at December 31, 2014 $ 39 $ 23 $ 7 $ 69 Accruals for Business Operations and IT (5 ) (3 ) 13 5 Payments and other adjustments (25 ) (9 ) (17 ) (51 ) Accrual Balance at December 31, 2015 $ 9 $ 11 $ 3 $ 23 Accruals for Business Operations and IT (2 ) — — (2 ) Accruals for Beacon 94 18 30 142 Payments and other adjustments (64 ) (12 ) (31 ) (107 ) Accrual Balance at December 31, 2016 $ 37 $ 17 $ 2 $ 56 Accruals for Beacon 186 32 27 245 Payments and Other Adjustments (57 ) (17 ) (26 ) (100 ) Accrual Balance at December 31, 2017 $ 166 $ 32 $ 3 $ 201

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The following table presents the components of income tax expense (benefit) for the periods indicated: Years Ended December 31, (In millions) 2017 2016 2015 Current: Federal $ 229 $ (14 ) $ 52 State 18 30 92 Non-U.S. 380 320 342 Total current expense 627 336 486 Deferred: Federal 49 (311 ) (39 ) State 65 38 40 Non-U.S. (19 ) (85 ) (169 ) Total deferred expense (benefit) 95 (358 ) (168 ) Total income tax expense (benefit) $ 722 $ (22 ) $ 318
Schedule of Effective Income Tax Rate Reconciliation	The following table presents a reconciliation of the U.S. statutory income tax rate to our effective tax rate based on income before income tax expense for the periods indicated: Years Ended December 31, 2017 2016 2015 U.S. federal income tax rate 35.0 % 35.0 % 35.0 % Changes from statutory rate: State taxes, net of federal benefit 1.9 2.0 4.2 Tax-exempt income (4.5 ) (6.1 ) (5.6 ) Business tax credits (1) (6.8 ) (13.6 ) (9.4 ) Foreign tax differential (7.4 ) (7.7 ) (9.6 ) Transition tax 15.7 — — Deferred tax revaluation (6.8 ) — — Foreign designated earnings (0.7 ) (6.8 ) — Foreign capital transactions — (4.3 ) — Tax refund — — (2.8 ) Litigation expense — 1.4 2.7 Other, net (1.5 ) (0.9 ) (0.7 ) Effective tax rate 24.9 % (1.0 )% 13.8 % (1) Business tax credits include low-income housing, production and investment tax credits.
Schedule of Deferred Tax Assets and Liabilities	The following table presents significant components of our gross deferred tax assets and gross deferred tax liabilities as of the dates indicated: December 31, (In millions) 2017 2016 Deferred tax assets: Unrealized losses on investment securities, net $ 17 $ 157 Deferred compensation 159 285 Defined benefit pension plan 82 116 Restructuring charges and other reserves 132 199 Foreign currency translation 18 225 General business credit 231 425 NOL and other carryforwards 101 73 Other 27 32 Total deferred tax assets 767 1,512 Valuation allowance for deferred tax assets (88 ) (66 ) Deferred tax assets, net of valuation allowance $ 679 $ 1,446 Deferred tax liabilities: Leveraged lease financing $ 184 $ 313 Fixed and intangible assets 755 886 Non-U.S. earnings 6 164 Investment basis differences 158 120 Total deferred tax liabilities $ 1,103 $ 1,483 The reduction in deferred tax assets and liabilities includes the provisional estimated impact of TCJA as well as current year activity such as the utilization of General Business Credits, additional investments in tax advantaged investments and changes in FX rates. The table below summarizes the deferred tax assets and related valuation allowances recognized as of December 31, 2017 : (In millions) Deferred Tax Asset Valuation Allowance Expiration General business Credits $ 231 $ — 2035-2037 NOLs - Non-U.S. 47 (35 ) 2018-2026 / None Other Carryforwards 41 (41 ) None NOLs - State 13 (12 ) 2018-2036
Summary of Income Tax Contingencies	The following table presents activity related to unrecognized tax benefits as of the dates indicated: December 31, (In millions) 2017 2016 2015 Beginning balance $ 71 $ 63 $ 163 Decrease related to agreements with tax authorities (14 ) (13 ) (122 ) Increase related to tax positions taken during current year 26 7 8 Increase related to tax positions taken during prior years 11 14 14 Ending balance $ 94 $ 71 $ 63

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following table presents the computation of basic and diluted earnings per common share for the periods indicated: Years Ended December 31, (Dollars in millions, except per share amounts) 2017 2016 2015 Net income $ 2,177 $ 2,143 $ 1,980 Less: Preferred stock dividends (182 ) (173 ) (130 ) Dividends and undistributed earnings allocated to participating securities (1) (2 ) (2 ) (2 ) Net income available to common shareholders $ 1,993 $ 1,968 $ 1,848 Average common shares outstanding (In thousands): Basic average common shares 374,793 391,485 407,856 Effect of dilutive securities: equity-based awards 5,420 4,605 5,782 Diluted average common shares 380,213 396,090 413,638 Anti-dilutive securities (2) 188 2,143 661 Earnings per Common Share: Basic $ 5.32 $ 5.03 $ 4.53 Diluted (3) 5.24 4.97 4.47 (1) Represents the portion of net income available to common equity allocated to participating securities, composed of unvested and fully vested SERP shares and fully vested deferred director stock awards, which are equity-based awards that contain non-forfeitable rights to dividends, and are considered to participate with the common stock in undistributed earnings. (2) Represents equity-based awards outstanding but not included in the computation of diluted average common shares, because their effect was anti-dilutive. Refer to Note 18 for additional information about equity-based awards. (3) Calculations reflect allocation of earnings to participating securities using the two-class method, as this computation is more dilutive than the treasury stock method.

Line of Business Information (T

Line of Business Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summary of Line of Business Results	The following is a summary of our line of business results for the periods indicated. The amounts in the “Other” columns were not allocated to State Street's business lines. Prior reported results reflect reclassifications, for comparative purposes, related to management changes in methodologies associated with allocations of revenue and expenses to lines of business in 2017 . Years Ended December 31, Investment Investment Other Total (Dollars in millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 2017 2016 2015 Servicing fees $ 5,365 $ 5,073 $ 5,153 $ — $ — $ — $ — $ — $ — $ 5,365 $ 5,073 $ 5,153 Management fees — — — 1,616 1,292 1,174 — — — 1,616 1,292 1,174 Trading services 999 1,038 1,091 72 61 55 — — — 1,071 1,099 1,146 Securities finance 606 562 496 — — — — — — 606 562 496 Processing fees and other 240 119 342 7 (29 ) (33 ) — — — 247 90 309 Total fee revenue 7,210 6,792 7,082 1,695 1,324 1,196 — — — 8,905 8,116 8,278 Net interest income 2,309 2,081 2,086 (5 ) 3 2 — — — 2,304 2,084 2,088 Gains (losses) related to investment securities, net (39 ) 7 (6 ) — — — — — — (39 ) 7 (6 ) Total revenue 9,480 8,880 9,162 1,690 1,327 1,198 — — — 11,170 10,207 10,360 Provision for loan losses 2 10 12 — — — — — — 2 10 12 Total expenses 6,717 6,660 6,990 1,286 1,218 962 266 199 98 8,269 8,077 8,050 Income before income tax expense $ 2,761 $ 2,210 $ 2,160 $ 404 $ 109 $ 236 $ (266 ) $ (199 ) $ (98 ) $ 2,899 $ 2,120 $ 2,298 Pre-tax margin 29 % 25 % 24 % 24 % 8 % 20 % 26 % 21 % 22 % Average assets (in billions) $ 214.0 $ 225.3 $ 246.6 $ 5.4 $ 4.4 $ 3.9 $ 219.4 $ 229.7 $ 250.5

Non-U.S. Activities (Tables)

Non-U.S. Activities (Tables)	12 Months Ended
	Dec. 31, 2017
Segments, Geographical Areas [Abstract]
Schedule of Results from Non-U.S. Operations	The following table presents our U.S. and non-U.S. financial results for the periods indicated: 2017 2016 2015 (In millions) Non-U.S. U.S. Total Non-U.S. U.S. Total Non-U.S. U.S. Total Total revenue $ 4,734 $ 6,436 $ 11,170 $ 4,419 $ 5,788 $ 10,207 $ 4,428 $ 5,932 $ 10,360 Income before income taxes 1,230 1,669 2,899 1,047 1,073 2,120 1,193 1,105 2,298

Parent Company Financial Stat58

Parent Company Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information Statement of Income of Parent Company	STATEMENT OF INCOME - PARENT COMPANY Years Ended December 31, (In millions) 2017 2016 2015 Cash dividends from consolidated banking subsidiary $ 2,224 $ 640 $ 585 Cash dividends from consolidated non-banking subsidiaries and unconsolidated entities 12 75 171 Other, net 127 92 73 Total revenue 2,363 807 829 Interest expense 297 249 209 Other expenses 94 107 310 Total expenses 391 356 519 Income tax benefit (86 ) (47 ) (186 ) Income before equity in undistributed income of consolidated subsidiaries and unconsolidated entities 2,058 498 496 Equity in undistributed income of consolidated subsidiaries and unconsolidated entities: Consolidated banking subsidiary 20 1,629 1,384 Consolidated non-banking subsidiaries and unconsolidated entities 99 16 100 Net income $ 2,177 $ 2,143 $ 1,980
Condensed Financial Information Statement of Condition of Parent Company	STATEMENT OF CONDITION - PARENT COMPANY December 31, (In millions) 2017 2016 Assets: Interest-bearing deposits with consolidated banking subsidiary $ 532 $ 3,635 Trading account assets 361 325 Investment securities available-for-sale 43 39 Investments in subsidiaries: Consolidated banking subsidiary 23,080 22,147 Consolidated non-banking subsidiaries 6,762 2,687 Unconsolidated entities 63 297 Notes and other receivables from: Consolidated banking subsidiary 2,973 2,743 Consolidated non-banking subsidiaries and unconsolidated entities 143 126 Other assets 263 461 Total assets $ 34,220 $ 32,460 Liabilities: Accrued expenses and other liabilities $ 917 $ 514 Long-term debt 10,986 10,727 Total liabilities 11,903 11,241 Shareholders’ equity 22,317 21,219 Total liabilities and shareholders’ equity $ 34,220 $ 32,460
Condensed Financial Information Statement of Cash Flows of Parent Company	STATEMENT OF CASH FLOWS - PARENT COMPANY Years Ended December 31, (In millions) 2017 2016 2015 Net cash provided by operating activities $ 2,047 $ 417 $ 926 Investing Activities: Net decrease (increase) in interest-bearing deposits with consolidated banking subsidiary 3,103 2,100 295 Investments in consolidated banking and non-banking subsidiaries (7,672 ) (7,600 ) (7,959 ) Sale or repayment of investment in consolidated banking and non-banking subsidiaries 4,216 6,703 7,891 Business acquisitions — (395 ) — Net increase in investments in unconsolidated affiliates 172 — — Net cash provided by (used in) investing activities (181 ) 808 227 Financing Activities: Net increase (decrease) in commercial paper — — (2,485 ) Proceeds from issuance of long-term debt, net of issuance costs 748 1,492 2,983 Payments for long-term debt (450 ) (1,000 ) — Proceeds from issuance of preferred stock, net of issuance costs — 493 742 Proceeds from exercises of common stock options — — 4 Purchases of common stock (1,292 ) (1,365 ) (1,520 ) Repurchases of common stock for employee tax withholding (104 ) (122 ) (222 ) Payments for cash dividends (768 ) (723 ) (655 ) Net cash used in financing activities (1,866 ) (1,225 ) (1,153 ) Net change — — — Cash and due from banks at beginning of year — — — Cash and due from banks at end of year $ — $ — $ —

Summary of Significant Accoun59

Summary of Significant Accounting Policies - Basis of Presentation (Details) $ in Millions	Jul. 01, 2016USD ($)	Sep. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2017segment	Dec. 31, 2017line_of_business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of lines of business					2	2
Boston Financial Data Services, Inc. and International Financial Data Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash received			$ 175
Common stock received			$ 158
Gain on sale				$ 30
Alternative Trading Platform
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale		$ 26
GE Asset Management
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price	$ 485

Summary of Significant Accoun60

Summary of Significant Accounting Policies - New Accounting Pronouncement (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in revenues		$ 11,170	$ 10,207	$ 10,360
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax benefit		$ 24.8
Forecast | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in revenues	$ 225
Subsequent Event | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Available-for-sale equity securities reclassified					$ 443
Equity securities held at fair value					$ 443

Fair Value - Narrative (Details

Fair Value - Narrative (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Assets, level 1 to level 2 transfers	$ 0	$ 0
Assets, level 2 to level 1 transfers	9,000,000	0
Liabilities, level 1 to level 2 transfers	0	0
Liabilities, level 2 to level 1 transfers	$ 0	$ 0

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value Measurements on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	$ 1,093	$ 1,024
Investment securities available-for-sale	57,121	61,998
Derivative asset, collateral, cash offset	(2,045)	(906)
Derivative liability, collateral, cash offset	(422)	(2,356)
Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,447	905
Non-US debt securities, covered bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,537	3,769
Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,885	988
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	1,093	1,024
Investment securities available-for-sale	57,121	61,998
Derivative asset, Impact of Netting	(7,593)	(9,231)
Derivative assets	4,013	7,321
Total	62,227	70,343
Derivative liability, Impact of Netting	(5,970)	(10,682)
Derivative liabilities	5,882	6,002
Total liabilities carried at fair value	5,921	6,002
Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, Impact of Netting	(7,593)	(9,163)
Derivative assets	4,004	7,321
Derivative liability, Impact of Netting	(5,970)	(10,456)
Derivative liabilities	5,498	5,500
Recurring | Interest-rate contracts(6)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, Impact of Netting	0	(68)
Derivative assets	8	0
Derivative liability, Impact of Netting	0	(226)
Derivative liabilities	100	122
Recurring | Other derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, Impact of Netting	0
Derivative assets	1
Derivative liability, Impact of Netting	0	0
Derivative liabilities	284	380
Recurring | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	39	30
Recurring | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	482	669
Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	572	325
Investment securities available-for-sale	2,560	2,469
Recurring | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	223	4,263
Recurring | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	10,872	13,257
Recurring | Total U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	11,095	17,520
Recurring | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,358	5,596
Recurring | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,542	1,351
Recurring | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		272
Recurring | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,447	905
Recurring | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	6,347	8,124
Recurring | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	6,695	6,535
Recurring | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	2,947	2,516
Recurring | Non-U.S. debt securities, Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	10,721	5,836
Recurring | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	6,108	5,613
Recurring | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	26,471	20,500
Recurring | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	9,151	10,322
Recurring | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,054	2,593
Recurring | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	46	42
Recurring | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		3
Recurring | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	397	409
Recurring | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		16
Quoted Market Prices in Active Markets (Level 1) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	472	525
Investment securities available-for-sale	11	3,824
Derivative asset	9	0
Total	492	4,349
Derivative liability	1	0
Total liabilities carried at fair value	40	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liability	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Interest-rate contracts(6)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	8	0
Derivative liability	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Other derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	1
Derivative liability	1	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	39	30
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	389	495
Quoted Market Prices in Active Markets (Level 1) | Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	44	0
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	11	3,824
Quoted Market Prices in Active Markets (Level 1) | Recurring | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Total U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	11	3,824
Quoted Market Prices in Active Markets (Level 1) | Recurring | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. debt securities, Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Quoted Market Prices in Active Markets (Level 1) | Recurring | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	621	499
Investment securities available-for-sale	54,984	56,837
Derivative asset	11,596	16,544
Total	67,201	73,880
Derivative liability	11,850	16,676
Total liabilities carried at fair value	11,850	16,676
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	11,596	16,476
Derivative liability	11,467	15,948
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Interest-rate contracts(6)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	68
Derivative liability	100	348
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Other derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0
Derivative liability	283	380
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0	0
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	93	174
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	528	325
Investment securities available-for-sale	2,560	2,469
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	212	439
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	10,872	13,257
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Total U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	11,084	13,696
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	3,358	5,499
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,542	1,351
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		272
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	89	0
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	4,989	7,122
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	6,576	6,535
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	2,545	2,484
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. debt securities, Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	10,721	5,836
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	5,904	5,365
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	25,746	20,220
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	9,108	10,283
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,054	2,577
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	46	42
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		3
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	397	409
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		16
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0	0
Investment securities available-for-sale	2,126	1,337
Derivative asset	1	8
Total	2,127	1,345
Derivative liability	1	8
Total liabilities carried at fair value	1	8
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	1	8
Derivative liability	1	8
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Interest-rate contracts(6)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liability	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Other derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0
Derivative liability	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0	0
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Total U.S. Treasury and federal agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	97
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,358	905
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	1,358	1,002
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	119	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	402	32
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. debt securities, Government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	204	248
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	725	280
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	43	39
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	16
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0	0
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		$ 0
Other | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account liabilities	39
Other | Quoted Market Prices in Active Markets (Level 1) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account liabilities	39
Other | Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account liabilities	0
Other | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account liabilities	0
Trading account liabilities, impact of netting	$ 0

Fair Value - Schedule of Fair63

Fair Value - Schedule of Fair Value Measurements, Assets, Using Significant Unobservable Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 1,345	$ 2,469
Total realized and unrealized gain (losses) recorded in revenue	(3)	41
Total realized and unrealized gain (losses) recorded in other comprehensive income	1	(9)
Purchases	1,776	1,394
Settlements	(605)	(1,370)
Transfers into Level 3	372
Transfers out of Level 3	(409)	(1,032)
Fair value, end of period	2,127	1,345
Change in unrealized gains (losses) related to financial instruments held	(3)	5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(350)	(148)
Derivative instruments, assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	8	5
Total realized and unrealized gain (losses) recorded in revenue	(7)	9
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0
Purchases	4	3
Settlements	(4)	(9)
Transfers into Level 3	0
Transfers out of Level 3	0	0
Fair value, end of period	1	8
Change in unrealized gains (losses) related to financial instruments held	(3)	5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	8	5
Total realized and unrealized gain (losses) recorded in revenue	(7)	9
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0
Purchases	4	3
Settlements	(4)	(9)
Transfers into Level 3	0
Transfers out of Level 3	0	0
Fair value, end of period	1	8
Change in unrealized gains (losses) related to financial instruments held	(3)	5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Investment securities available-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	1,337	2,464
Total realized and unrealized gain (losses) recorded in revenue	4	32
Total realized and unrealized gain (losses) recorded in other comprehensive income	1	(9)
Purchases	1,772	1,391
Settlements	(601)	(1,361)
Transfers into Level 3	372
Transfers out of Level 3	(409)	(1,032)
Fair value, end of period	2,126	1,337
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(350)	(148)
US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	0	0
Total realized and unrealized gain (losses) recorded in revenue	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0
Purchases	0	325
Settlements	0	0
Transfers into Level 3	25
Transfers out of Level 3	(25)	(325)
Fair value, end of period	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Asset-backed securities, student loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	97	189
Total realized and unrealized gain (losses) recorded in revenue	0	1
Total realized and unrealized gain (losses) recorded in other comprehensive income	1	3
Purchases	200	0
Settlements	0	0
Transfers into Level 3	0
Transfers out of Level 3	(298)	(96)
Fair value, end of period	0	97
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Asset-backed securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	905	1,764
Total realized and unrealized gain (losses) recorded in revenue	3	31
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	(23)
Purchases	1,035	469
Settlements	(620)	(1,254)
Transfers into Level 3	275
Transfers out of Level 3	0	0
Fair value, end of period	1,358	905
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(240)	(82)
Total asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	1,002	1,953
Total realized and unrealized gain (losses) recorded in revenue	3	32
Total realized and unrealized gain (losses) recorded in other comprehensive income	1	(20)
Purchases	1,235	469
Settlements	(620)	(1,254)
Transfers into Level 3	275
Transfers out of Level 3	(298)	(96)
Fair value, end of period	1,358	1,002
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(240)	(82)
Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	0	0
Total realized and unrealized gain (losses) recorded in revenue	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	(2)	0
Purchases	119	90
Settlements	2	0
Transfers into Level 3	0
Transfers out of Level 3	0	(90)
Fair value, end of period	119	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Non-U.S. debt securities, asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	32	174
Total realized and unrealized gain (losses) recorded in revenue	1	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0
Purchases	370	196
Settlements	(11)	(60)
Transfers into Level 3	67
Transfers out of Level 3	(47)	(278)
Fair value, end of period	402	32
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(10)	0
Non-U.S. debt securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	248	255
Total realized and unrealized gain (losses) recorded in revenue	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	1	0
Purchases	5	222
Settlements	31	(7)
Transfers into Level 3	0
Transfers out of Level 3	0	(222)
Fair value, end of period	204	248
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(81)	0
Total non-U.S. debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	280	429
Total realized and unrealized gain (losses) recorded in revenue	1	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	(1)	0
Purchases	494	508
Settlements	22	(67)
Transfers into Level 3	67
Transfers out of Level 3	(47)	(590)
Fair value, end of period	725	280
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(91)	0
State and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	39	33
Total realized and unrealized gain (losses) recorded in revenue	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	2	9
Purchases	0	0
Settlements	(3)	(3)
Transfers into Level 3	5
Transfers out of Level 3	0	0
Fair value, end of period	43	39
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	16	39
Total realized and unrealized gain (losses) recorded in revenue	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	(1)	2
Purchases	24	89
Settlements	0	(27)
Transfers into Level 3	0
Transfers out of Level 3	(39)	(21)
Fair value, end of period	0	16
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	(66)
Other U.S. debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	0	10
Total realized and unrealized gain (losses) recorded in revenue	0	0
Total realized and unrealized gain (losses) recorded in other comprehensive income	0	0
Purchases	19	0
Settlements	0	(10)
Transfers into Level 3	0
Transfers out of Level 3	0	0
Fair value, end of period	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(19)	0
Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	5,970	10,682
Derivative Liability	5,882	6,002
Recurring | Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	5,970	10,456
Derivative Liability	5,498	5,500
Recurring | Interest-rate contracts(6)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	0	226
Derivative Liability	100	122
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	11,850	16,676
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	11,467	15,948
Pricing Methods with Significant Observable Market Inputs (Level 2) | Recurring | Interest-rate contracts(6)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	100	348
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	1	8
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	1	8
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Recurring | Interest-rate contracts(6)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	1	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	0	0
Quoted Market Prices in Active Markets (Level 1) | Recurring | Interest-rate contracts(6)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability	$ 0	$ 0

Fair Value - Fair Value Inputs,

Fair Value - Fair Value Inputs, Assets and Liabilities, Quantitative Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available-for-sale	$ 57,121	$ 61,998
Asset-backed securities, other
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available-for-sale	1,447	905
State and political subdivisions
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available-for-sale	$ 9,151	$ 10,322
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Asset-backed securities, other | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	0.00%	0.30%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | State and political subdivisions | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	0.00%	1.80%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Option model | Derivative instruments, liabilities | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Volatility	7.20%	14.40%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Option model | Derivative instruments, assets | Weighted average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Volatility	7.20%	14.40%
Significant Unobservable Inputs Readily Available | Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Total	$ 1	$ 48
Total	1	8
Significant Unobservable Inputs Readily Available | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, liabilities
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts	1	8
Significant Unobservable Inputs Readily Available | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, assets
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative instruments, foreign exchange contracts	1	8
Significant Unobservable Inputs Readily Available | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available-for-sale	0	1
Significant Unobservable Inputs Readily Available | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Investment securities available-for-sale	$ 0	$ 39

Fair Value - Carrying Value and

Fair Value - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Assets:
Cash and due from banks	$ 2,107	$ 1,314	$ 1,207	$ 1,855
Interest-bearing deposits with banks	67,227	70,935
Securities purchased under resale agreements	3,241	1,956
Investment securities held-to-maturity	40,255	34,994
Financial Liabilities:
Non-interest-bearing	47,175	59,397
Interest-bearing—U.S.	50,139	30,911
Interest-bearing—non-U.S.	87,582	96,855
Securities sold under repurchase agreements	2,842	4,400
Other short-term borrowings	1,144	1,585
Reported Amount
Financial Assets:
Cash and due from banks	2,107	1,314
Interest-bearing deposits with banks	67,227	70,935
Securities purchased under resale agreements	3,241	1,956
Investment securities held-to-maturity	40,458	35,169
Net loans (excluding leases)	22,577	18,862
Financial Liabilities:
Non-interest-bearing	47,175	59,397
Interest-bearing—U.S.	50,139	30,911
Interest-bearing—non-U.S.	87,582	96,855
Securities sold under repurchase agreements	2,842	4,400
Other short-term borrowings	1,144	1,585
Long-term debt	11,620	11,430
Estimated Fair Value
Financial Assets:
Cash and due from banks	2,107	1,314
Interest-bearing deposits with banks	67,227	70,935
Securities purchased under resale agreements	3,241	1,956
Investment securities held-to-maturity	40,255	34,994
Net loans (excluding leases)	22,482	18,877
Financial Liabilities:
Non-interest-bearing	47,175	59,397
Interest-bearing—U.S.	50,139	30,911
Interest-bearing—non-U.S.	87,582	96,855
Securities sold under repurchase agreements	2,842	4,400
Other short-term borrowings	1,144	1,585
Long-term debt	11,919	11,618
Estimated Fair Value | Quoted Market Prices in Active Markets (Level 1)
Financial Assets:
Cash and due from banks	2,107	1,314
Interest-bearing deposits with banks	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	16,814	17,400
Net loans (excluding leases)	0	0
Financial Liabilities:
Non-interest-bearing	0	0
Interest-bearing—U.S.	0	0
Interest-bearing—non-U.S.	0	0
Securities sold under repurchase agreements	0	0
Other short-term borrowings	0	0
Long-term debt	0	0
Estimated Fair Value | Pricing Methods with Significant Observable Market Inputs (Level 2)
Financial Assets:
Cash and due from banks	0	0
Interest-bearing deposits with banks	67,227	70,935
Securities purchased under resale agreements	3,241	1,956
Investment securities held-to-maturity	23,318	17,439
Net loans (excluding leases)	22,431	18,781
Financial Liabilities:
Non-interest-bearing	47,175	59,397
Interest-bearing—U.S.	50,139	30,911
Interest-bearing—non-U.S.	87,582	96,855
Securities sold under repurchase agreements	2,842	4,400
Other short-term borrowings	1,144	1,585
Long-term debt	11,639	11,282
Estimated Fair Value | Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Financial Assets:
Cash and due from banks	0	0
Interest-bearing deposits with banks	0	0
Securities purchased under resale agreements	0	0
Investment securities held-to-maturity	123	155
Net loans (excluding leases)	51	96
Financial Liabilities:
Non-interest-bearing	0	0
Interest-bearing—U.S.	0	0
Interest-bearing—non-U.S.	0	0
Securities sold under repurchase agreements	0	0
Other short-term borrowings	0	0
Long-term debt	280	$ 336
Nonrecurring Measurement Basis | Estimated Fair Value
Financial Assets:
Net loans (excluding leases)	$ 3

Investment Securities - Narrati

Investment Securities - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)security	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Pledged securities not separately reported	$ 48,000	$ 46,000
Loss on sale	113	5	$ 62
Available-for-sale securities transferred	496	4,900
Available-for-sale securities, gross unrealized gain	(2.8)	87
Net impairment losses	0	3	1
US Treasury and federal agencies, mortgage-backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Securities sold	12,200
Loss on sale	39
Agency securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net impairment losses	$ 0	0	0
Federal family education loan program
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Asset Backed Securities, Average Remaining Term	4 years 7 months 6 days
Net impairment losses	$ 0	0	0
Asset-backed securities, student loans
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net impairment losses	0	0	0
Less than maximum credit exposure	70
Non-U.S. debt securities, mortgage-backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net impairment losses	1	2	1
State and political subdivisions
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net impairment losses	0	0	0
U.S. Non-Agency Residential Mortgage-Backed Securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net impairment losses	0	0	0
U.S. Non-Agency Commercial Mortgage-Backed Securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net impairment losses	0	$ 1	$ 0
Gross pre-tax unrealized losses	$ 657
Number of securities in loss position | security	1,283
Minimum
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale securities transferred to held to maturity	10 years
Maximum
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale securities transferred to held to maturity	42 years

Investment Securities - Schedul

Investment Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	$ 56,952	$ 62,056
Available for sale, gross unrealized gains	437	427
Available for sale, gross unrealized losses	268	485
Investment securities available-for-sale	57,121	61,998
Held to maturity, amortized cost	40,458	35,169
Held to maturity, gross unrealized gains	186	160
Held to maturity, gross unrealized losses	389	335
Investment securities held-to-maturity	40,255	34,994
US Treasury and federal agencies, direct obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	222	4,265
Available for sale, gross unrealized gains	2	7
Available for sale, gross unrealized losses	1	9
Investment securities available-for-sale	223	4,263
Held to maturity, amortized cost	17,028	17,527
Held to maturity, gross unrealized gains	0	17
Held to maturity, gross unrealized losses	143	58
Investment securities held-to-maturity	16,885	17,486
US Treasury and federal agencies, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	10,975	13,340
Available for sale, gross unrealized gains	26	76
Available for sale, gross unrealized losses	129	159
Investment securities available-for-sale	10,872	13,257
Held to maturity, amortized cost	16,651	10,334
Held to maturity, gross unrealized gains	22	20
Held to maturity, gross unrealized losses	225	221
Investment securities held-to-maturity	16,448	10,133
Total U.S. Treasury and federal agencies
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	11,197	17,605
Available for sale, gross unrealized gains	28	83
Available for sale, gross unrealized losses	130	168
Investment securities available-for-sale	11,095	17,520
Held to maturity, amortized cost	33,679	27,861
Held to maturity, gross unrealized gains	22	37
Held to maturity, gross unrealized losses	368	279
Investment securities held-to-maturity	33,333	27,619
Asset-backed securities, student loans
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	3,325	5,659
Available for sale, gross unrealized gains	37	12
Available for sale, gross unrealized losses	4	75
Investment securities available-for-sale	3,358	5,596
Held to maturity, amortized cost	3,047	2,883
Held to maturity, gross unrealized gains	32	5
Held to maturity, gross unrealized losses	9	30
Investment securities held-to-maturity	3,070	2,858
Asset-backed securities, credit cards
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,565	1,377
Available for sale, gross unrealized gains	2	0
Available for sale, gross unrealized losses	25	26
Investment securities available-for-sale	1,542	1,351
Held to maturity, amortized cost	798	897
Held to maturity, gross unrealized gains	2	2
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	800	899
Asset-backed securities, sub-prime
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	0	289
Available for sale, gross unrealized gains	0	1
Available for sale, gross unrealized losses	0	18
Investment securities available-for-sale	0	272
Asset-backed securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,440	895
Available for sale, gross unrealized gains	7	10
Available for sale, gross unrealized losses	0	0
Investment securities available-for-sale	1,447	905
Held to maturity, amortized cost	1	35
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	1	35
Total asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	6,330	8,220
Available for sale, gross unrealized gains	46	23
Available for sale, gross unrealized losses	29	119
Investment securities available-for-sale	6,347	8,124
Held to maturity, amortized cost	3,846	3,815
Held to maturity, gross unrealized gains	34	7
Held to maturity, gross unrealized losses	9	30
Investment securities held-to-maturity	3,871	3,792
Non-U.S. debt securities, mortgage-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	6,664	6,506
Available for sale, gross unrealized gains	36	35
Available for sale, gross unrealized losses	5	6
Investment securities available-for-sale	6,695	6,535
Held to maturity, amortized cost	939	1,150
Held to maturity, gross unrealized gains	82	70
Held to maturity, gross unrealized losses	6	15
Investment securities held-to-maturity	1,015	1,205
Non-U.S. debt securities, asset-backed securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,942	2,513
Available for sale, gross unrealized gains	5	4
Available for sale, gross unrealized losses	0	1
Investment securities available-for-sale	2,947	2,516
Held to maturity, amortized cost	263	531
Held to maturity, gross unrealized gains	1	0
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	264	531
Non-U.S. debt securities, Government securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	10,754	5,834
Available for sale, gross unrealized gains	16	8
Available for sale, gross unrealized losses	49	6
Investment securities available-for-sale	10,721	5,836
Held to maturity, amortized cost	474	286
Held to maturity, gross unrealized gains	2	3
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	476	289
Non-U.S. debt securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	6,076	5,587
Available for sale, gross unrealized gains	38	31
Available for sale, gross unrealized losses	6	5
Investment securities available-for-sale	6,108	5,613
Held to maturity, amortized cost	48	113
Held to maturity, gross unrealized gains	0	1
Held to maturity, gross unrealized losses	0	0
Investment securities held-to-maturity	48	114
Total non-U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	26,436	20,440
Available for sale, gross unrealized gains	95	78
Available for sale, gross unrealized losses	60	18
Investment securities available-for-sale	26,471	20,500
Held to maturity, amortized cost	1,724	2,080
Held to maturity, gross unrealized gains	85	74
Held to maturity, gross unrealized losses	6	15
Investment securities held-to-maturity	1,803	2,139
State and political subdivisions
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	8,929	10,233
Available for sale, gross unrealized gains	245	201
Available for sale, gross unrealized losses	23	112
Investment securities available-for-sale	9,151	10,322
Collateralized mortgage obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	1,060	2,610
Available for sale, gross unrealized gains	3	18
Available for sale, gross unrealized losses	9	35
Investment securities available-for-sale	1,054	2,593
Held to maturity, amortized cost	1,209	1,413
Held to maturity, gross unrealized gains	45	42
Held to maturity, gross unrealized losses	6	11
Investment securities held-to-maturity	1,248	1,444
Other U.S. debt securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	2,563	2,481
Available for sale, gross unrealized gains	12	18
Available for sale, gross unrealized losses	15	30
Investment securities available-for-sale	2,560	2,469
U.S. equity securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	40	39
Available for sale, gross unrealized gains	8	6
Available for sale, gross unrealized losses	2	3
Investment securities available-for-sale	46	42
Non-U.S. equity securities
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	0	3
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	0
Investment securities available-for-sale	0	3
U.S. money-market mutual funds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	397	409
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	0
Investment securities available-for-sale	397	409
Non-U.S. money-market mutual funds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Available for sale, amortized cost	0	16
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	0	0
Investment securities available-for-sale	$ 0	16
Federal family education loan program
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Federal government credit support guarantee, percentage minimum	97.00%
Collateralized loan obligations
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Investment securities available-for-sale	$ 1,447	905
Non-US debt securities, covered bonds
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Investment securities available-for-sale	3,537	3,769
Non-U.S. debt securities, other
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Investment securities available-for-sale	$ 1,885	$ 988

Investment Securities - Sched68

Investment Securities - Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	$ 18,094	$ 16,928
Available for sale, gross unrealized losses less than 12 months	131	308
Available for sale, fair value 12 months or longer	6,391	7,800
Available for sale, gross unrealized losses 12 months or longer	137	177
Available for sale, fair value total	24,485	24,728
Available for sale, gross unrealized losses total	268	485
Held to maturity, fair value less than 12 months	21,664	17,284
Held-to-maturity, gross, less than 12 months	150	293
Held to maturity, fair value 12 months or longer	9,373	1,899
Held to maturity, gross unrealized losses 12 months or longer	239	42
Held to maturity, fair value total	31,037	19,183
Held to maturity, gross unrealized losses total	389	335
US Treasury and federal agencies, direct obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	0	651
Available for sale, gross unrealized losses less than 12 months	0	8
Available for sale, fair value 12 months or longer	67	180
Available for sale, gross unrealized losses 12 months or longer	1	1
Available for sale, fair value total	67	831
Available for sale, gross unrealized losses total	1	9
Held to maturity, fair value less than 12 months	14,439	8,891
Held-to-maturity, gross, less than 12 months	109	57
Held to maturity, fair value 12 months or longer	2,447	86
Held to maturity, gross unrealized losses 12 months or longer	34	1
Held to maturity, fair value total	16,886	8,977
Held to maturity, gross unrealized losses total	143	58
US Treasury and federal agencies, mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	5,161	7,072
Available for sale, gross unrealized losses less than 12 months	31	131
Available for sale, fair value 12 months or longer	3,341	1,114
Available for sale, gross unrealized losses 12 months or longer	98	28
Available for sale, fair value total	8,502	8,186
Available for sale, gross unrealized losses total	129	159
Held to maturity, fair value less than 12 months	6,785	6,838
Held-to-maturity, gross, less than 12 months	38	221
Held to maturity, fair value 12 months or longer	5,988	0
Held to maturity, gross unrealized losses 12 months or longer	187	0
Held to maturity, fair value total	12,773	6,838
Held to maturity, gross unrealized losses total	225	221
Total U.S. Treasury and federal agencies
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	5,161	7,723
Available for sale, gross unrealized losses less than 12 months	31	139
Available for sale, fair value 12 months or longer	3,408	1,294
Available for sale, gross unrealized losses 12 months or longer	99	29
Available for sale, fair value total	8,569	9,017
Available for sale, gross unrealized losses total	130	168
Held to maturity, fair value less than 12 months	21,224	15,729
Held-to-maturity, gross, less than 12 months	147	278
Held to maturity, fair value 12 months or longer	8,435	86
Held to maturity, gross unrealized losses 12 months or longer	221	1
Held to maturity, fair value total	29,659	15,815
Held to maturity, gross unrealized losses total	368	279
Asset-backed securities, student loans
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	0	54
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	769	3,745
Available for sale, gross unrealized losses 12 months or longer	4	75
Available for sale, fair value total	769	3,799
Available for sale, gross unrealized losses total	4	75
Held to maturity, fair value less than 12 months	440	705
Held-to-maturity, gross, less than 12 months	3	9
Held to maturity, fair value 12 months or longer	423	1,235
Held to maturity, gross unrealized losses 12 months or longer	6	21
Held to maturity, fair value total	863	1,940
Held to maturity, gross unrealized losses total	9	30
Asset-backed securities, credit cards
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,289	795
Available for sale, gross unrealized losses less than 12 months	25	1
Available for sale, fair value 12 months or longer	0	494
Available for sale, gross unrealized losses 12 months or longer	0	25
Available for sale, fair value total	1,289	1,289
Available for sale, gross unrealized losses total	25	26
Held to maturity, fair value less than 12 months		33
Held-to-maturity, gross, less than 12 months		0
Held to maturity, fair value 12 months or longer		0
Held to maturity, gross unrealized losses 12 months or longer		0
Held to maturity, fair value total		33
Held to maturity, gross unrealized losses total		0
Asset-backed securities, sub-prime
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		1
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		252
Available for sale, gross unrealized losses 12 months or longer		18
Available for sale, fair value total		253
Available for sale, gross unrealized losses total		18
Asset-backed securities, other
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		75
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		0
Available for sale, gross unrealized losses 12 months or longer		0
Available for sale, fair value total		75
Available for sale, gross unrealized losses total		0
Held to maturity, fair value less than 12 months		18
Held-to-maturity, gross, less than 12 months		0
Held to maturity, fair value 12 months or longer		9
Held to maturity, gross unrealized losses 12 months or longer		0
Held to maturity, fair value total		27
Held to maturity, gross unrealized losses total		0
Asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,289	925
Available for sale, gross unrealized losses less than 12 months	25	1
Available for sale, fair value 12 months or longer	769	4,491
Available for sale, gross unrealized losses 12 months or longer	4	118
Available for sale, fair value total	2,058	5,416
Available for sale, gross unrealized losses total	29	119
Held to maturity, fair value less than 12 months	440	756
Held-to-maturity, gross, less than 12 months	3	9
Held to maturity, fair value 12 months or longer	423	1,244
Held to maturity, gross unrealized losses 12 months or longer	6	21
Held to maturity, fair value total	863	2,000
Held to maturity, gross unrealized losses total	9	30
Non-U.S. debt securities, mortgage-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,059	442
Available for sale, gross unrealized losses less than 12 months	4	1
Available for sale, fair value 12 months or longer	469	893
Available for sale, gross unrealized losses 12 months or longer	1	5
Available for sale, fair value total	1,528	1,335
Available for sale, gross unrealized losses total	5	6
Held to maturity, fair value less than 12 months	0	54
Held-to-maturity, gross, less than 12 months	0	2
Held to maturity, fair value 12 months or longer	239	330
Held to maturity, gross unrealized losses 12 months or longer	6	13
Held to maturity, fair value total	239	384
Held to maturity, gross unrealized losses total	6	15
Non-U.S. debt securities, asset-backed securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months		253
Available for sale, gross unrealized losses less than 12 months		0
Available for sale, fair value 12 months or longer		276
Available for sale, gross unrealized losses 12 months or longer		1
Available for sale, fair value total		529
Available for sale, gross unrealized losses total		1
Held to maturity, fair value less than 12 months		28
Held-to-maturity, gross, less than 12 months		0
Held to maturity, fair value 12 months or longer		35
Held to maturity, gross unrealized losses 12 months or longer		0
Held to maturity, fair value total		63
Held to maturity, gross unrealized losses total		0
Government securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	7,629	1,314
Available for sale, gross unrealized losses less than 12 months	48	6
Available for sale, fair value 12 months or longer	68	0
Available for sale, gross unrealized losses 12 months or longer	1	0
Available for sale, fair value total	7,697	1,314
Available for sale, gross unrealized losses total	49	6
Held to maturity, fair value less than 12 months		180
Held-to-maturity, gross, less than 12 months		0
Held to maturity, fair value 12 months or longer		0
Held to maturity, gross unrealized losses 12 months or longer		0
Held to maturity, fair value total		180
Held to maturity, gross unrealized losses total		0
Non-U.S. debt securities, other
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	816	670
Available for sale, gross unrealized losses less than 12 months	4	4
Available for sale, fair value 12 months or longer	289	218
Available for sale, gross unrealized losses 12 months or longer	2	1
Available for sale, fair value total	1,105	888
Available for sale, gross unrealized losses total	6	5
Total non-U.S. debt securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	9,504	2,679
Available for sale, gross unrealized losses less than 12 months	56	11
Available for sale, fair value 12 months or longer	826	1,387
Available for sale, gross unrealized losses 12 months or longer	4	7
Available for sale, fair value total	10,330	4,066
Available for sale, gross unrealized losses total	60	18
Held to maturity, fair value less than 12 months	0	262
Held-to-maturity, gross, less than 12 months	0	2
Held to maturity, fair value 12 months or longer	239	365
Held to maturity, gross unrealized losses 12 months or longer	6	13
Held to maturity, fair value total	239	627
Held to maturity, gross unrealized losses total	6	15
State and political subdivisions
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	734	3,390
Available for sale, gross unrealized losses less than 12 months	6	102
Available for sale, fair value 12 months or longer	901	304
Available for sale, gross unrealized losses 12 months or longer	17	10
Available for sale, fair value total	1,635	3,694
Available for sale, gross unrealized losses total	23	112
Collateralized mortgage obligations
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	399	1,259
Available for sale, gross unrealized losses less than 12 months	5	31
Available for sale, fair value 12 months or longer	136	162
Available for sale, gross unrealized losses 12 months or longer	4	4
Available for sale, fair value total	535	1,421
Available for sale, gross unrealized losses total	9	35
Held to maturity, fair value less than 12 months	0	537
Held-to-maturity, gross, less than 12 months	0	4
Held to maturity, fair value 12 months or longer	276	204
Held to maturity, gross unrealized losses 12 months or longer	6	7
Held to maturity, fair value total	276	741
Held to maturity, gross unrealized losses total	6	11
Other U.S. debt securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	1,007	944
Available for sale, gross unrealized losses less than 12 months	8	24
Available for sale, fair value 12 months or longer	345	157
Available for sale, gross unrealized losses 12 months or longer	7	6
Available for sale, fair value total	1,352	1,101
Available for sale, gross unrealized losses total	15	30
U.S. equity securities
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]
Available for sale, fair value less than 12 months	0	8
Available for sale, gross unrealized losses less than 12 months	0	0
Available for sale, fair value 12 months or longer	6	5
Available for sale, gross unrealized losses 12 months or longer	2	3
Available for sale, fair value total	6	13
Available for sale, gross unrealized losses total	$ 2	$ 3

Investment Securities - Sched69

Investment Securities - Schedule of Contractual Maturities of Debt Securities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	$ 5,187
Available for sale, 1 to 5 Years	21,238
Available for sale, 6 to 10 Years	17,388
Available for sale, over 10 Years	12,865
Available-for-sale, fair value	56,678
Held to maturity, under 1 Year	2,720
Held to maturity, 1 to 5 Years	16,762
Held to maturity, 6 to 10 Years	2,272
Held to maturity, over 10 Years	18,704
Held to maturity, amortized cost	40,458	$ 35,169
US Treasury and federal agencies, direct obligations
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	0
Available for sale, 1 to 5 Years	12
Available for sale, 6 to 10 Years	6
Available for sale, over 10 Years	205
Available-for-sale, fair value	223
Held to maturity, under 1 Year	1,988
Held to maturity, 1 to 5 Years	14,968
Held to maturity, 6 to 10 Years	14
Held to maturity, over 10 Years	58
Held to maturity, amortized cost	17,028	17,527
US Treasury and federal agencies, mortgage-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	96
Available for sale, 1 to 5 Years	762
Available for sale, 6 to 10 Years	3,123
Available for sale, over 10 Years	6,891
Available-for-sale, fair value	10,872
Held to maturity, under 1 Year	0
Held to maturity, 1 to 5 Years	162
Held to maturity, 6 to 10 Years	1,605
Held to maturity, over 10 Years	14,884
Held to maturity, amortized cost	16,651	10,334
Total U.S. Treasury and federal agencies
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	96
Available for sale, 1 to 5 Years	774
Available for sale, 6 to 10 Years	3,129
Available for sale, over 10 Years	7,096
Available-for-sale, fair value	11,095
Held to maturity, under 1 Year	1,988
Held to maturity, 1 to 5 Years	15,130
Held to maturity, 6 to 10 Years	1,619
Held to maturity, over 10 Years	14,942
Held to maturity, amortized cost	33,679	27,861
Asset-backed securities, student loans
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	289
Available for sale, 1 to 5 Years	1,044
Available for sale, 6 to 10 Years	685
Available for sale, over 10 Years	1,340
Available-for-sale, fair value	3,358
Held to maturity, under 1 Year	35
Held to maturity, 1 to 5 Years	245
Held to maturity, 6 to 10 Years	265
Held to maturity, over 10 Years	2,502
Held to maturity, amortized cost	3,047	2,883
Asset-backed securities, credit cards
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	0
Available for sale, 1 to 5 Years	1,290
Available for sale, 6 to 10 Years	252
Available for sale, over 10 Years	0
Available-for-sale, fair value	1,542
Held to maturity, under 1 Year	178
Held to maturity, 1 to 5 Years	620
Held to maturity, 6 to 10 Years	0
Held to maturity, over 10 Years	0
Held to maturity, amortized cost	798	897
Asset-backed securities, other
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	0
Available for sale, 1 to 5 Years	350
Available for sale, 6 to 10 Years	956
Available for sale, over 10 Years	141
Available-for-sale, fair value	1,447
Held to maturity, under 1 Year	0
Held to maturity, 1 to 5 Years	0
Held to maturity, 6 to 10 Years	0
Held to maturity, over 10 Years	1
Held to maturity, amortized cost	1	35
Total asset-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	289
Available for sale, 1 to 5 Years	2,684
Available for sale, 6 to 10 Years	1,893
Available for sale, over 10 Years	1,481
Available-for-sale, fair value	6,347
Held to maturity, under 1 Year	213
Held to maturity, 1 to 5 Years	865
Held to maturity, 6 to 10 Years	265
Held to maturity, over 10 Years	2,503
Held to maturity, amortized cost	3,846	3,815
Non-U.S. debt securities, mortgage-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	551
Available for sale, 1 to 5 Years	4,502
Available for sale, 6 to 10 Years	602
Available for sale, over 10 Years	1,040
Available-for-sale, fair value	6,695
Held to maturity, under 1 Year	132
Held to maturity, 1 to 5 Years	217
Held to maturity, 6 to 10 Years	45
Held to maturity, over 10 Years	545
Held to maturity, amortized cost	939	1,150
Non-U.S. debt securities, asset-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	205
Available for sale, 1 to 5 Years	2,185
Available for sale, 6 to 10 Years	557
Available for sale, over 10 Years	0
Available-for-sale, fair value	2,947
Held to maturity, under 1 Year	26
Held to maturity, 1 to 5 Years	237
Held to maturity, 6 to 10 Years	0
Held to maturity, over 10 Years	0
Held to maturity, amortized cost	263	531
Government securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	2,195
Available for sale, 1 to 5 Years	3,201
Available for sale, 6 to 10 Years	4,448
Available for sale, over 10 Years	877
Available-for-sale, fair value	10,721
Held to maturity, under 1 Year	353
Held to maturity, 1 to 5 Years	121
Held to maturity, 6 to 10 Years	0
Held to maturity, over 10 Years	0
Held to maturity, amortized cost	474	286
Non-U.S. debt securities, other
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	1,078
Available for sale, 1 to 5 Years	4,235
Available for sale, 6 to 10 Years	758
Available for sale, over 10 Years	37
Available-for-sale, fair value	6,108
Held to maturity, under 1 Year	0
Held to maturity, 1 to 5 Years	48
Held to maturity, 6 to 10 Years	0
Held to maturity, over 10 Years	0
Held to maturity, amortized cost	48	113
Total non-U.S. debt securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	4,029
Available for sale, 1 to 5 Years	14,123
Available for sale, 6 to 10 Years	6,365
Available for sale, over 10 Years	1,954
Available-for-sale, fair value	26,471
Held to maturity, under 1 Year	511
Held to maturity, 1 to 5 Years	623
Held to maturity, 6 to 10 Years	45
Held to maturity, over 10 Years	545
Held to maturity, amortized cost	1,724	2,080
State and political subdivisions
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	474
Available for sale, 1 to 5 Years	2,415
Available for sale, 6 to 10 Years	4,724
Available for sale, over 10 Years	1,538
Available-for-sale, fair value	9,151
Collateralized mortgage obligations
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	3
Available for sale, 1 to 5 Years	145
Available for sale, 6 to 10 Years	170
Available for sale, over 10 Years	736
Available-for-sale, fair value	1,054
Held to maturity, under 1 Year	8
Held to maturity, 1 to 5 Years	144
Held to maturity, 6 to 10 Years	343
Held to maturity, over 10 Years	714
Held to maturity, amortized cost	1,209	$ 1,413
Other U.S. debt securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 Year	296
Available for sale, 1 to 5 Years	1,097
Available for sale, 6 to 10 Years	1,107
Available for sale, over 10 Years	60
Available-for-sale, fair value	$ 2,560

Investment Securities - Gains a

Investment Securities - Gains and Losses Related to Investment Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Gross realized gains from sales of AFS investment securities	$ 74	$ 15	$ 57
Gross realized losses from sales of AFS investment securities	(113)	(5)	(62)
Gross losses from OTTI	0	(2)	(1)
Losses reclassified (from) to other comprehensive income	0	(1)	0
Gains (losses) related to investment securities, net	(39)	7	(6)
Impairment associated with expected credit losses	0	(1)	0
Impairment associated with adverse changes in timing of expected future cash flows	0	(2)	(1)
Net impairment losses	$ 0	$ (3)	$ (1)

Investment Securities - Sched71

Investment Securities - Schedule of Credit-Related Loss Activity Recognized In Earnings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 66	$ 92	$ 115
Losses for which OTTI was previously recognized	0	2	1
Previously recognized losses related to securities sold or matured	(2)	(28)	(24)
Balance, end of period	$ 64	$ 66	$ 92

Loans and Leases - Narrative (D

Loans and Leases - Narrative (Details)	12 Months Ended
	Dec. 31, 2017USD ($)loan	Dec. 31, 2016USD ($)loan
Financing Receivable, Recorded Investment [Line Items]
Loans and leases pledged as collateral | $	$ 1,900,000,000	$ 1,500,000,000
Number of impaired loans and leases | loan	0
Allowance for loan and lease losses | $	$ 54,000,000	$ 53,000,000
Loans modified in troubled debt restructurings | loan	0	0
Loans more than 90 days past due | loan	0	0
Commercial and Financial
Financing Receivable, Recorded Investment [Line Items]
Number of impaired loans and leases | loan		1
Recorded Investment | $		$ 15,000,000
Unpaid Principal Balance | $		15,000,000
Interest Income Recognized | $		0
Allowance for loan and lease losses | $		$ 200,000
Number of loans on non-accrual status | loan	0	1
Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Number of loans on non-accrual status | loan		0

Loans and Leases - Net Loans (D

Loans and Leases - Net Loans (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 23,294	$ 19,757
Allowance for loan and lease losses	(54)	(53)
Loans and leases, net of allowance	23,240	19,704
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to investment funds	13,618	11,734
Senior secured bank loans	2,923	3,256
Loans to municipalities	2,105	1,352
Other	50	70
Commercial real estate	98	27
Lease financing	267	338
Total loans and leases	19,061	16,777
Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to investment funds	3,213	2,224
Senior secured bank loans	624	252
Lease financing	396	504
Total loans and leases	$ 4,233	$ 2,980

Loans and Leases - Schedule of

Loans and Leases - Schedule of Investment in Leveraged Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Abstract]
Net rental income receivable	$ 808	$ 1,039
Estimated residual values	89	89
Unearned income	(234)	(286)
Investment in leveraged lease financing	663	842
Less: related deferred income tax liabilities	(184)	(313)
Net investment in leveraged lease financing	$ 479	$ 529

Loans and Leases - Recorded Inv

Loans and Leases - Recorded Investment in Each Class of Total Loans and Leases by Credit Quality Indicator (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 23,294	$ 19,757
Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	22,533	18,888
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	98	27
Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	663	842
Investment grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	18,627	15,758
Investment grade | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	17,866	14,889
Investment grade | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	98	27
Investment grade | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	663	842
Speculative
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4,638	3,984
Speculative | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4,638	3,984
Speculative | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
Speculative | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	29
Special Mention | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	29
Special Mention | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0
Special Mention | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 0
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases		15
Substandard | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases		15
Substandard | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases		0
Substandard | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases		$ 0

Loans and Leases - Schedule o76

Loans and Leases - Schedule of Allowance for Loan Losses (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 23,294	$ 19,757
Loans and leases, allowance for losses	54	53
Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	22,533	18,888
Loans and leases, allowance for losses		0.2
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	98	27
Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	663	842
Individually evaluated for impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	15
Individually evaluated for impairment | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	15
Individually evaluated for impairment | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
Individually evaluated for impairment | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	0	0
Collectively evaluated for impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	23,294	19,742
Collectively evaluated for impairment | Commercial and Financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	22,533	18,873
Collectively evaluated for impairment | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	98	27
Collectively evaluated for impairment | Lease Financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 663	$ 842

Loans and Leases - Schedule o77

Loans and Leases - Schedule of Activity In The Allowance For Loan Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 53	$ 46	$ 38
Provision for loan and lease losses	2	10	12
Charge-offs	(1)	(3)	(4)
Ending balance	$ 54	$ 53	$ 46

Goodwill and Other Intangible78

Goodwill and Other Intangible Assets - Narrative (Details)	12 Months Ended
	Dec. 31, 2017
Client relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of other intangible assets	5 years
Client relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of other intangible assets	20 years
Core deposits | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life of other intangible assets	16 years
Core deposits | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life of other intangible assets	22 years

Goodwill and Other Intangible79

Goodwill and Other Intangible Assets - Changes In The Carrying Amount Of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Ending balance December 31, 2015	$ 5,814	$ 5,671
Acquisitions	17	236
Divestitures and other reductions	(9)	(11)
Foreign currency translation	200	(82)
Ending balance December 31, 2016	6,022	5,814
Investment Servicing
Goodwill [Roll Forward]
Ending balance December 31, 2015	5,550	5,641
Acquisitions	17	0
Divestitures and other reductions	(9)	(11)
Foreign currency translation	194	(80)
Ending balance December 31, 2016	5,752	5,550
Investment Management
Goodwill [Roll Forward]
Ending balance December 31, 2015	264	30
Acquisitions	0	236
Divestitures and other reductions	0	0
Foreign currency translation	6	(2)
Ending balance December 31, 2016	$ 270	$ 264

Goodwill and Other Intangible80

Goodwill and Other Intangible Assets - Changes In The Carrying Amount Of Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 1,750	$ 1,768
Acquisitions	16	217
Divestitures	(11)	(8)
Amortization	(214)	(207)	$ (197)
Foreign currency translation and other, net	72	(20)
Ending balance	1,613	1,750	1,768
Investment Servicing
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	1,539	1,753
Acquisitions	16	0
Divestitures	(11)	(8)
Amortization	(183)	(186)
Foreign currency translation and other, net	71	(20)
Ending balance	1,432	1,539	1,753
Investment Management
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	211	15
Acquisitions	0	217
Divestitures	0	0
Amortization	(31)	(21)
Foreign currency translation and other, net	1	0
Ending balance	$ 181	$ 211	$ 15

Goodwill and Other Intangible81

Goodwill and Other Intangible Assets - Gross Carrying Amount, Accumulated Amortization And Net Carrying Amount Of Other Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,497	$ 3,413
Accumulated Amortization	(1,884)	(1,663)
Net Carrying Amount	1,613	1,750	$ 1,768
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,669	2,620
Accumulated Amortization	(1,470)	(1,306)
Net Carrying Amount	1,199	1,314
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	686	661
Accumulated Amortization	(320)	(277)
Net Carrying Amount	366	384
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	142	132
Accumulated Amortization	(94)	(80)
Net Carrying Amount	$ 48	$ 52

Goodwill and Other Intangible82

Goodwill and Other Intangible Assets - Amortization Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of other intangible assets	$ 214	$ 207	$ 197
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2,018	191
2,019	174
2,020	171
2,021	166
2,022	$ 165

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Other Assets [Abstract]
Receivable - securities lending	$ 19,404	$ 21,204
Derivative instruments, net	4,013	7,321
Bank-owned life insurance	3,242	3,158
Investments in joint ventures and other unconsolidated entities	2,259	2,363
Collateral, net	473	2,236
Prepaid expenses	364	333
Accounts receivable	348	886
Receivable for securities settlement	188	40
Deposits with clearing organizations	120	132
Deferred tax assets, net of valuation allowance	113	210
Income taxes receivable	97	106
Other	397	339
Total	$ 31,018	$ 38,328

Deposits - Narrative (Details)

Deposits - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Demand deposits of $100,000 or more	$ 39,730	$ 55,030
Demand deposit overdrafts	3,240	2,620
Non-U.S.
Loans and Leases Receivable Disclosure [Line Items]
Demand deposits of $100,000 or more	252	$ 214
Wholesale CDs
Loans and Leases Receivable Disclosure [Line Items]
Demand deposits of $100,000 or more	4,750
Customer Deposits
Loans and Leases Receivable Disclosure [Line Items]
Demand deposits of $100,000 or more	$ 34,730

Short-Term Borrowings - Narrati

Short-Term Borrowings - Narrative (Details) CAD in Millions	Dec. 31, 2017USD ($)	Dec. 31, 2017CAD	Dec. 31, 2016USD ($)
Short-term Debt [Line Items]
Weighted-average interest rate as of year-end	0.25%	0.25%	0.13%
Average balance of securities purchased under agreement to resell and securities sold under agreement to repurchase	$ 31,150,000,000		$ 30,860,000,000
Maximum borrowing on line of credit	1,110,000,000	CAD 1,400
Balance on line of credit	0		$ 0
U.S. Government Securities Sold
Short-term Debt [Line Items]
Fair value of overnight maturity	$ 2,899,000,000

Short-Term Borrowings - Outstan

Short-Term Borrowings - Outstanding and weighted-average interest rates of short-term borrowings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Weighted-average interest rate as of year-end	0.25%	0.13%
Securities Sold Under Repurchase Agreements
Short-term Debt [Line Items]
Balance as of December 31	$ 2,842	$ 4,400	$ 4,499
Maximum outstanding as of any month-end	4,302	5,572	10,977
Average outstanding during the year	$ 3,683	$ 4,113	$ 8,875
Weighted-average interest rate as of year-end	0.03%	0.04%	0.02%
Weighted-average interest rate during the year	0.05%	0.02%	0.01%
Federal Funds Purchased
Short-term Debt [Line Items]
Balance as of December 31	$ 0	$ 0	$ 6
Maximum outstanding as of any month-end	0	29	29
Average outstanding during the year	$ 1	$ 31	$ 21
Weighted-average interest rate as of year-end	0.00%	0.00%	0.03%
Weighted-average interest rate during the year	0.00%	0.17%	0.01%
Tax-Exempt Investment Program
Short-term Debt [Line Items]
Balance as of December 31	$ 1,078	$ 1,158	$ 1,748
Maximum outstanding as of any month-end	1,158	1,726	1,865
Average outstanding during the year	$ 1,127	$ 1,512	$ 1,807
Weighted-average interest rate as of year-end	1.45%	0.67%	0.03%
Weighted-average interest rate during the year	0.79%	0.36%	0.06%

Short-Term Borrowings - Overnig

Short-Term Borrowings - Overnight maturity (Details) $ in Millions	Dec. 31, 2017USD ($)
U.S. Government Securities Sold
Short-term Debt [Line Items]
Amortized cost of overnight maturity	$ 2,928
Fair value of overnight maturity	2,899
Repurchase Agreements
Short-term Debt [Line Items]
Amortized cost of overnight maturity	$ 2,842

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total long-term debt	$ 11,620	$ 11,430
Fair Value Hedges
Debt Instrument [Line Items]
Increase (decrease) in carrying value of long-term debt	$ (87)	(15)
Senior notes | 3.55% notes due 2025
Debt Instrument [Line Items]
Interest rate on debt	3.55%
Senior notes | 2.55% notes due 2020
Debt Instrument [Line Items]
Interest rate on debt	2.55%
Senior notes | 3.7% notes due in 2023
Debt Instrument [Line Items]
Interest rate on debt	3.70%
Senior notes | 3.3% notes due 2024
Debt Instrument [Line Items]
Interest rate on debt	3.30%
Senior notes | 2.653% notes due 2023
Debt Instrument [Line Items]
Interest rate on debt	2.653%
Senior notes | 4.375% notes due 2021
Debt Instrument [Line Items]
Interest rate on debt	4.375%
Senior notes | 1.95% Notes Due 2021
Debt Instrument [Line Items]
Interest rate on debt	1.95%
Senior notes | 2.65% notes due 2026
Debt Instrument [Line Items]
Interest rate on debt	2.65%
Senior notes | 1.35% notes due 2018
Debt Instrument [Line Items]
Interest rate on debt	1.35%
Senior notes | 7.35% notes due 2026
Debt Instrument [Line Items]
Interest rate on debt	7.35%
Senior notes | 5.375% notes due 2017
Debt Instrument [Line Items]
Interest rate on debt	5.375%
Subordinated note | 3.1% subordinated notes due 2023
Debt Instrument [Line Items]
Interest rate on debt	3.10%
Subordinated note | 5.25% subordinated notes due 2018
Debt Instrument [Line Items]
Interest rate on debt	5.25%
Junior Subordinated Debt | 4.956% junior subordinated debentures due 2018
Debt Instrument [Line Items]
Interest rate on debt	4.956%
Parent Company and Non-banking Subsidiaries | Senior notes | 3.55% notes due 2025
Debt Instrument [Line Items]
Long-term debt	$ 1,287	1,293
Parent Company and Non-banking Subsidiaries | Senior notes | 2.55% notes due 2020
Debt Instrument [Line Items]
Long-term debt	1,184	1,192
Parent Company and Non-banking Subsidiaries | Senior notes | 3.7% notes due in 2023
Debt Instrument [Line Items]
Long-term debt	1,021	1,033
Parent Company and Non-banking Subsidiaries | Senior notes | 3.3% notes due 2024
Debt Instrument [Line Items]
Long-term debt	993	999
Parent Company and Non-banking Subsidiaries | Senior notes | 2.653% notes due 2023
Debt Instrument [Line Items]
Long-term debt	740	0
Parent Company and Non-banking Subsidiaries | Senior notes | 4.375% notes due 2021
Debt Instrument [Line Items]
Long-term debt	734	738
Parent Company and Non-banking Subsidiaries | Senior notes | 1.95% Notes Due 2021
Debt Instrument [Line Items]
Long-term debt	724	726
Parent Company and Non-banking Subsidiaries | Senior notes | 2.65% notes due 2026
Debt Instrument [Line Items]
Long-term debt	706	704
Parent Company and Non-banking Subsidiaries | Senior notes | Floating-rate notes due 2020
Debt Instrument [Line Items]
Long-term debt	499	499
Parent Company and Non-banking Subsidiaries | Senior notes | 1.35% notes due 2018
Debt Instrument [Line Items]
Long-term debt	499	497
Parent Company and Non-banking Subsidiaries | Senior notes | 7.35% notes due 2026
Debt Instrument [Line Items]
Long-term debt	150	150
Parent Company and Non-banking Subsidiaries | Senior notes | 5.375% notes due 2017
Debt Instrument [Line Items]
Long-term debt	0	450
Parent Company and Non-banking Subsidiaries | Subordinated note | 3.1% subordinated notes due 2023
Debt Instrument [Line Items]
Long-term debt	981	987
Parent Company and Non-banking Subsidiaries | Junior Subordinated Debt | Floating-rate subordinated notes due to State Street Capital Trust IV in 2037
Debt Instrument [Line Items]
Long-term debt	793	793
Parent Company and Non-banking Subsidiaries | Junior Subordinated Debt | 4.956% junior subordinated debentures due 2018
Debt Instrument [Line Items]
Long-term debt	502	511
Parent Company and Non-banking Subsidiaries | Junior Subordinated Debt | Floating-rate subordinated notes due to State Street Capital Trust I in 2028
Debt Instrument [Line Items]
Long-term debt	150	150
Parent Company and Non-banking Subsidiaries | Capital Lease Obligations
Debt Instrument [Line Items]
Long-term capital leases	250	293
State Street Bank | Subordinated note | 5.25% subordinated notes due 2018
Debt Instrument [Line Items]
Long-term debt	$ 407	$ 415

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Capital lease obligation	$ 159	$ 194
Building and Parking Garage
Debt Instrument [Line Items]
Capital lease obligation	$ 244	$ 278

Derivative Financial Instrume90

Derivative Financial Instruments - Narrative (Details)	12 Months Ended
	Dec. 31, 2017USD ($)security	Dec. 31, 2016USD ($)
Derivative [Line Items]
Cash collateral received for derivative instruments	$ 2,550,000,000	$ 1,990,000,000
Cash collateral provided for derivative instruments	869,000,000	4,390,000,000
Fair value of derivative liabilities	$ 11,852,000,000	$ 16,684,000,000
Weighted average life of trusts	4 years 7 months	4 years 6 months
Senior notes
Derivative [Line Items]
Number of securities	8
Subordinated note
Derivative [Line Items]
Number of securities	1
LIBOR Indexed Floating Rate Loans
Derivative [Line Items]
Term of debt instrument	4 years 10 months 24 days
Credit swap agreements
Derivative [Line Items]
Fair value of derivative liabilities	$ 1,130,000,000
Fair value of collateral posted	0
Maximum additional amount of payments related to termination events	$ 1,130,000,000
Interest rate swap | Fair Value Hedges | Senior notes
Derivative [Line Items]
Number of securities | security	8
Interest rate swap | Fair Value Hedges | Subordinated note
Derivative [Line Items]
Number of securities | security	1

Derivative Financial Instrume91

Derivative Financial Instruments - Schedule of Interest Rate Derivatives (Details) - Interest rate swap - Fair Value Hedges	Dec. 31, 2017
Senior notes | 2.55% notes due 2020
Derivative [Line Items]
Fixed interest rate	2.55%
Senior notes | 4.38% note due 2021
Derivative [Line Items]
Fixed interest rate	4.375%
Senior notes | 1.95% Notes Due 2021
Derivative [Line Items]
Fixed interest rate	1.95%
Senior notes | 2.65% Notes Due 2022
Derivative [Line Items]
Fixed interest rate	2.653%
Senior notes | 3.7% notes due in 2023
Derivative [Line Items]
Fixed interest rate	3.70%
Senior notes | 3.3% notes due 2024
Derivative [Line Items]
Fixed interest rate	3.30%
Senior notes | 3.55% notes due 2025
Derivative [Line Items]
Fixed interest rate	3.55%
Senior notes | 2.65% notes due 2026
Derivative [Line Items]
Fixed interest rate	2.65%
Subordinated note | 3.10% subordinated note due 2023
Derivative [Line Items]
Fixed interest rate	3.10%

Derivative Financial Instrume92

Derivative Financial Instruments - Schedule of Outstanding Hedges: (Notional Amount) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	$ 11,047	$ 10,169
Additional compensation and employee benefits expense due to accelerated vesting	249
Derivatives not designated as hedging instruments | Interest-rate contracts(6) | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	2,392	13,455
Derivatives not designated as hedging instruments | Foreign exchange contracts | Futures
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	50	0
Derivatives not designated as hedging instruments | Foreign exchange contracts | Forward, swap and spot
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	1,679,976	1,414,765
Derivatives not designated as hedging instruments | Foreign exchange contracts | Options purchased
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	350	337
Derivatives not designated as hedging instruments | Foreign exchange contracts | Options written
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	302	202
Derivatives not designated as hedging instruments | Commodity and Equity Contracts | Commodity
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	16	0
Derivatives not designated as hedging instruments | Commodity and Equity Contracts | Equity
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	50	0
Derivatives not designated as hedging instruments | Other contracts | Stable value contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	26,653	27,182
Derivatives not designated as hedging instruments | Other contracts | Deferred value awards
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	473	409
Additional compensation and employee benefits expense due to accelerated vesting		249
Derivatives designated as hedging instruments | Interest-rate contracts(6) | Swap agreements
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	11,047	10,169
Derivatives designated as hedging instruments | Foreign exchange contracts | Forward and swap
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivatives	$ 28,913	$ 8,564

Derivative Financial Instrume93

Derivative Financial Instruments - Notional Amount of Interest Rate Swap Agreements Designated as Fair Value and Cash Flow Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Total	$ 11,047	$ 10,169
Investment securities available-for-sale
Derivative [Line Items]
Investment securities available-for-sale	1,254	1,444
Long-term debt
Derivative [Line Items]
Long-term debt	8,493	8,725
Floating-rate loans
Derivative [Line Items]
Long-term debt	1,300	0
Fair Value Hedges
Derivative [Line Items]
Total	9,747	10,169
Increase in carrying value of long-term debt	87	15
Fair Value Hedges | Investment securities available-for-sale
Derivative [Line Items]
Investment securities available-for-sale	1,254	1,444
Fair Value Hedges | Long-term debt
Derivative [Line Items]
Long-term debt	8,493	8,725
Fair Value Hedges | Floating-rate loans
Derivative [Line Items]
Long-term debt	0	0
Cash Flow Hedges
Derivative [Line Items]
Total	1,300	0
Cash Flow Hedges | Investment securities available-for-sale
Derivative [Line Items]
Investment securities available-for-sale	0	0
Cash Flow Hedges | Long-term debt
Derivative [Line Items]
Long-term debt	0	0
Cash Flow Hedges | Floating-rate loans
Derivative [Line Items]
Long-term debt	$ 1,300	$ 0

Derivative Financial Instrume94

Derivative Financial Instruments - Contractual and Weighted-Average Interest Rates, Which Include the Effects of Hedges Related to Financial Instruments (Details) - Long-term debt	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Contractual rates	3.34%	3.40%
Rate including impact of hedges	2.66%	2.29%

Derivative Financial Instrume95

Derivative Financial Instruments - Schedule of The Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 11,606	$ 16,552
Fair value of derivative liabilities	11,852	16,684
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	11,597	16,484
Fair value of derivative liabilities	11,467	15,956
Interest-rate contracts(6)
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	8	68
Fair value of derivative liabilities	100	348
Derivatives not designated as hedging instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	11,478	15,982
Derivatives not designated as hedging instruments | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	11,645	16,261
Derivatives not designated as hedging instruments | Foreign exchange contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	11,477	15,982
Derivatives not designated as hedging instruments | Foreign exchange contracts | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	11,361	15,881
Derivatives not designated as hedging instruments | Other derivative contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	1	0
Derivatives not designated as hedging instruments | Other derivative contracts | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	284	380
Derivatives designated as hedging instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	128	570
Derivatives designated as hedging instruments | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	207	423
Derivatives designated as hedging instruments | Foreign exchange contracts | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	120	502
Derivatives designated as hedging instruments | Foreign exchange contracts | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	107	75
Derivatives designated as hedging instruments | Interest-rate contracts(6) | Other Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	8	68
Derivatives designated as hedging instruments | Interest-rate contracts(6) | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 100	$ 348

Derivative Financial Instrume96

Derivative Financial Instruments - Impact of Derivatives on Consolidated Statement of Income (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	$ 474	$ 205	$ 542
Foreign exchange contracts | Trading services
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	632	662	686
Foreign exchange contracts | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	(23)	0	0
Interest-rate contracts(6) | Trading services
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	8	(7)	(2)
Interest-rate contracts(6) | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	0	1	0
Credit derivative contracts | Trading services
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	0	(1)	(1)
Other derivative contracts | Trading services
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	0	(2)	8
Other derivative contracts | Compensation and employee benefits
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income	$ (143)	$ (448)	$ (149)

Derivative Financial Instrume97

Derivative Financial Instruments - Schedule of Differences Between the Gains (Losses) on the Derivative and The Gains (Losses) on the Hedged Item (Details) - USD ($)	3 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Net unrealized gains (losses) on available-for-sale securities designated in fair value hedges, net of related taxes	$ (4,000,000)	$ (13,000,000)	$ (22,000,000)	$ (23,000,000)	$ (12,000,000)
Derivatives designated as hedging instruments | Fair Value Hedges | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			645,000,000	160,000,000	(265,000,000)
Gain (loss) on fair value hedges recognized in earnings			(642,000,000)	(155,000,000)	271,000,000
Derivatives designated as hedging instruments | Fair Value Hedges | Investment securities available-for-sale | Interest-rate contracts(6) | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			39,000,000	43,000,000	16,000,000
Gain (loss) on fair value hedges recognized in earnings			(37,000,000)	(40,000,000)	(17,000,000)
Derivatives designated as hedging instruments | Fair Value Hedges | Investment securities available-for-sale | Foreign exchange contracts | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			18,000,000	(6,000,000)	(101,000,000)
Gain (loss) on fair value hedges recognized in earnings			(18,000,000)	6,000,000	101,000,000
Derivatives designated as hedging instruments | Fair Value Hedges | Deposits | Foreign exchange contracts | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			626,000,000	221,000,000	(241,000,000)
Gain (loss) on fair value hedges recognized in earnings			(626,000,000)	(221,000,000)	241,000,000
Derivatives designated as hedging instruments | Fair Value Hedges | Long-term debt | Interest-rate contracts(6) | Processing fees and other revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			(38,000,000)	(98,000,000)	61,000,000
Gain (loss) on fair value hedges recognized in earnings			39,000,000	100,000,000	(54,000,000)
Derivatives designated as hedging instruments | Cash Flow Hedges
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			26,000,000	24,000,000	10,000,000
Gain (loss) on derivative recognized in OCI			(118,000,000)	(39,000,000)	55,000,000
Gain (loss) on hedges reclassified to income			0	0	(4,000,000)
Derivatives designated as hedging instruments | Cash Flow Hedges | Interest-rate contracts(6)
Derivative [Line Items]
Gain (loss) on derivative recognized in OCI			(14,000,000)	0	0
Derivatives designated as hedging instruments | Cash Flow Hedges | Interest-rate contracts(6) | Net interest revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			2,000,000	0	0
Gain (loss) on hedges reclassified to income			0	0	(4,000,000)
Derivatives designated as hedging instruments | Cash Flow Hedges | Foreign exchange contracts
Derivative [Line Items]
Gain (loss) on derivative recognized in OCI			(104,000,000)	(39,000,000)	55,000,000
Derivatives designated as hedging instruments | Cash Flow Hedges | Foreign exchange contracts | Net interest revenue
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			24,000,000	24,000,000	10,000,000
Gain (loss) on hedges reclassified to income			0	0	0
Derivatives designated as hedging instruments | Investment Hedges
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			0	0	0
Gain (loss) on derivative recognized in OCI			(160,000,000)	109,000,000	0
Gain (loss) on hedges reclassified to income			0	0	0
Derivatives designated as hedging instruments | Investment Hedges | Foreign exchange contracts
Derivative [Line Items]
Gain (loss) on derivative recognized in OCI			(160,000,000)	109,000,000	0
Derivatives designated as hedging instruments | Investment Hedges | Foreign exchange contracts | Gains (Losses) related to investment securities, net
Derivative [Line Items]
Amount of gain (loss) on derivative recognized in income			0	0	0
Gain (loss) on hedges reclassified to income			$ 0	$ 0	$ 0

Offsetting Arrangements - Narra

Offsetting Arrangements - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Offsetting [Abstract]
Fair Value of securities received as collateral that can be resold or repledged	$ 2,470	$ 1,770
Fair Value of securities received as collateral that have been resold or repledged	$ 15	$ 166

Offsetting Arrangements - Asset

Offsetting Arrangements - Assets With Offsetting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	$ 11,606	$ 16,552
Derivatives, Gross Amounts Offset in Statement of Condition	(7,593)	(9,231)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	4,013	7,321
Derivatives, Net Amount	3,889	7,074
Derivatives, Cash collateral and securities netting, offset	(2,045)	(906)
Derivatives, Cash collateral and securities netting, Cash and Securities Received	(124)	(247)
Derivatives, Cash collateral and securities netting, Net	(2,169)	(1,153)
Resale agreements and securities borrowing, Gross Amounts of Recognized Assets	70,079	58,677
Resale agreements and securities borrowing, Gross Amounts Offset in Statement of Condition	(47,434)	(35,517)
Resale agreements and securities borrowing, Net Amounts of Assets Presented in Statement of Condition	22,645	23,160
Resale agreements and securities borrowing, Cash and Securities Received	(22,645)	(22,939)
Resale agreements and securities borrowing, Net Amount	0	221
Total derivatives and other financial instruments, Gross Amounts of Recognized Assets	81,685	75,229
Total derivatives and other financial instruments, Gross Amounts Offset in Statement of Condition	(55,027)	(44,748)
Total derivatives and other financial instruments, Net Amounts of Assets Presented in Statement of Condition	26,658	30,481
Total derivatives and other financial instruments, Cash and Securities Received(5)	(22,769)	(23,186)
Total derivatives and other financial instruments, Net Amount	3,889	7,295
Securities purchased under resale agreements	3,241	1,956
Securities borrowed subject to master netting arrangements	(19,404)	(21,204)
Foreign exchange contracts
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	11,597	16,484
Derivatives, Gross Amounts Offset in Statement of Condition	(5,548)	(8,257)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	6,049	8,227
Derivatives, Net Amount	6,049	8,227
Interest-rate contracts(6)
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	8	68
Derivatives, Gross Amounts Offset in Statement of Condition	0	(68)
Derivatives, Net Amounts of Assets Presented in Statement of Condition	8	0
Derivatives, Net Amount	8	$ 0
Other derivative contracts
Offsetting Assets [Line Items]
Derivatives, Gross Amounts of Recognized Assets	1
Derivatives, Gross Amounts Offset in Statement of Condition	0
Derivatives, Net Amounts of Assets Presented in Statement of Condition	1
Derivatives, Net Amount	$ 1

Offsetting Arrangements - Liabi

Offsetting Arrangements - Liabilities With Offsetting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	$ 11,852	$ 16,684
Derivatives, Gross amounts offset in statement of condition	(5,970)	(10,682)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	5,882	6,002
Derivative, Net Amount	5,432	5,822
Derivatives, Cash and collateral securities netting, offset	(422)	(2,356)
Derivatives, Cash and collateral securities netting, Cash and Securities Provided	(450)	(180)
Derivatives, Cash and collateral securities netting, Net	(872)	(2,536)
Resale agreements and securities lending, Gross Amounts of Recognized Liabilities(1)(2)	54,127	44,933
Resale agreements and securities lending, Gross Amounts Offset in Statement of Condition(3)	(47,434)	(35,517)
Resale agreements and securities lending, Net Amounts of Liabilities Presented in Statement of Condition	6,693	9,416
Resale agreements and securities lending, Cash and Securities Provided	(4,299)	(7,059)
Resale agreements and securities lending, Net Amount	2,394	2,357
Total derivatives and other financial instruments, Gross Amounts of Recognized Liabilities	65,979	61,617
Total derivatives and other financial instruments, Gross Amounts Offset in Statement of Condition	(53,404)	(46,199)
Total derivatives and other financial instruments, Net Amounts of Liabilities Presented in Statement of Condition	12,575	15,418
Total derivatives and other financial instruments, Cash and Securities Provided	(4,749)	(7,239)
Total derivatives and other financial instruments, Net Amount	7,826	8,179
Securities sold under repurchase agreements	2,842	4,400
Securities lending, fair value, amount not offset against collateral	3,851	5,016
Foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	11,467	15,956
Derivatives, Gross amounts offset in statement of condition	(5,548)	(8,253)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	5,919	7,703
Derivative, Net Amount	5,919	7,703
Interest-rate contracts(6)
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	100	348
Derivatives, Gross amounts offset in statement of condition	0	(73)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	100	275
Derivative, Net Amount	100	275
Other derivative contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	285	380
Derivatives, Gross amounts offset in statement of condition	0	0
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	285	380
Derivative, Net Amount	$ 285	$ 380

Offsetting Arrangements - Repo,

Offsetting Arrangements - Repo, Sec Lending Transactions Maturity By Category (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	$ 43,072	$ 35,509
Securities lending transactions	11,055	9,424
Gross amount of recognized liabilities for repurchase agreements and securities lending	54,127	44,933
Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	43,072	35,509
Securities lending transactions	11,055	8,390
Gross amount of recognized liabilities for repurchase agreements and securities lending	54,127	43,899
Up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
Securities lending transactions	0	0
Gross amount of recognized liabilities for repurchase agreements and securities lending	0	0
30 – 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
Securities lending transactions	0	1,034
Gross amount of recognized liabilities for repurchase agreements and securities lending	0	1,034
U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	43,072	35,509
U.S. Treasury and agency securities | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	43,072	35,509
U.S. Treasury and agency securities | Up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
U.S. Treasury and agency securities | 30 – 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	35	53
Corporate debt securities | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	35	53
Corporate debt securities | Up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
Corporate debt securities | 30 – 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	11,020	9,371
Equity securities | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	11,020	8,337
Equity securities | Up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
Equity securities | 30 – 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	$ 1,034
Non-U.S. sovereign debt
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0
Non-U.S. sovereign debt | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0
Non-U.S. sovereign debt | Up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0
Non-U.S. sovereign debt | 30 – 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	$ 0

Commitments and Guarantees - Na

Commitments and Guarantees - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Unfunded commitments to extend credit, short term	72.00%
Term of unfunded commitment	1 year
Cash collateral provided for securities lending	$ 19,400	$ 21,200
Accrued expenses and other liabilities
Loss Contingencies [Line Items]
Cash collateral received in connection to securities finance activities	$ 3,850	$ 5,020

Commitments and Guarantees - Co

Commitments and Guarantees - Contractual Amounts of Credit-Related Off-Balance Sheet Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Unfunded credit facilities	$ 26,488	$ 26,993
Indemnified securities financing	381,817	360,452
Stable value protection	26,653	27,182
Standby letters of credit	$ 3,158	$ 3,459

Commitments and Guarantees - Sc

Commitments and Guarantees - Schedule Of Repurchase Agreements (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Fair value of indemnified securities financing	$ 381,817	$ 360,452
Fair value of cash and securities held by us, as agent, as collateral for indemnified securities financing	400,828	377,919
Fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements	61,270	60,003
Fair value of cash and securities held by us or our agents as collateral for investments in indemnified repurchase agreements	$ 65,272	$ 63,959

Contingencies - Narrative (Deta

Contingencies - Narrative (Details)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Estimate of possible loss	$ 12,000,000
Minimum
Loss Contingencies [Line Items]
Estimate of possible loss	0
Maximum
Loss Contingencies [Line Items]
Estimate of possible loss	15,000,000
Legal Reserve | Invoicing Matter
Loss Contingencies [Line Items]
Estimate of possible loss	$ 360,000,000

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Investment securities related to state and political subdivisions	$ 1,250,000	$ 1,350,000
Variable interest entity, other short-term borrowings	$ 1,080,000	$ 1,160,000
Weighted average life of trusts	4 years 7 months	4 years 6 months
Total standby bond-purchase agreement committed to trusts	$ 1,100,000
Total letters of credit committed to trusts	351,000
Standby purchase agreements and letters of credit commitments utilized	0
VIE - primary beneficiary
Variable Interest Entity [Line Items]
Assets	149,390	$ 0
Liabilities	49,780	0
Potential maximum loss exposure of unconsolidated funds	100,000
VIE - not primary beneficiary
Variable Interest Entity [Line Items]
Potential maximum loss exposure of unconsolidated funds	$ 72,000	$ 121,000

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Preferred Shares Outstanding (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Proceeds from issuance of preferred stock, net	$ 0	$ 493	$ 742
Series C Preferred Stock, Depository Share
Class of Stock [Line Items]
Depositary shares issued (shares)	20,000,000
Liquidation preference per share (USD per share)	$ 25
Series C Preferred Stock
Class of Stock [Line Items]
Ownership Interest Per Depositary Share	0.025%
Liquidation preference per share (USD per share)	$ 100,000
Proceeds from issuance of preferred stock, net	$ 488
Series D Preferred Stock, Depository Share
Class of Stock [Line Items]
Depositary shares issued (shares)	30,000,000
Liquidation preference per share (USD per share)	$ 25
Series D Preferred Stock
Class of Stock [Line Items]
Ownership Interest Per Depositary Share	0.025%
Liquidation preference per share (USD per share)	$ 100,000
Proceeds from issuance of preferred stock, net	$ 742
Series E Preferred Stock, Depository Share
Class of Stock [Line Items]
Depositary shares issued (shares)	30,000,000
Liquidation preference per share (USD per share)	$ 25
Series E Preferred Stock
Class of Stock [Line Items]
Ownership Interest Per Depositary Share	0.025%
Liquidation preference per share (USD per share)	$ 100,000
Proceeds from issuance of preferred stock, net	$ 728
Series F Preferred Stock, Depository Share
Class of Stock [Line Items]
Depositary shares issued (shares)	750,000
Liquidation preference per share (USD per share)	$ 1,000
Series F Preferred Stock
Class of Stock [Line Items]
Ownership Interest Per Depositary Share	1.00%
Liquidation preference per share (USD per share)	$ 100,000
Proceeds from issuance of preferred stock, net	$ 742
Series G Preferred Stock, Depository Share
Class of Stock [Line Items]
Depositary shares issued (shares)	20,000,000
Liquidation preference per share (USD per share)	$ 25
Series G Preferred Stock
Class of Stock [Line Items]
Ownership Interest Per Depositary Share	0.025%
Liquidation preference per share (USD per share)	$ 100,000
Proceeds from issuance of preferred stock, net	$ 493

Shareholders' Equity - Sched108

Shareholders' Equity - Schedule of Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Feb. 28, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Dividends Payable [Line Items]
Preferred stock cash dividend		$ 182	$ 173	$ 130
Common Stock Dividends Declared (in USD per share)		$ 1.6	$ 1.44	$ 1.32
Common Stock Dividends		$ 596	$ 559	$ 536
Series C Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 5,250	$ 5,250
Preferred stock cash dividend		$ 26	$ 26
Series C Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 1.32	$ 1.32
Series D Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 5,900	$ 5,900
Preferred stock cash dividend		$ 44	$ 44
Series D Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 1.48	$ 1.48
Series E Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 6,000	$ 6,000
Preferred stock cash dividend		$ 45	$ 45
Series E Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 1.52	$ 1.52
Series F Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 5,250	$ 5,250
Preferred stock cash dividend		$ 40	$ 40
Series F Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 52.5	$ 52.50
Series G Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 5,352	$ 3,626
Preferred stock cash dividend		$ 27	$ 18
Series G Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)		$ 1.32	$ 0.90
Subsequent Event | Series C Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,313
Preferred stock cash dividend	$ 6
Subsequent Event | Series C Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.33
Subsequent Event | Series D Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,475
Preferred stock cash dividend	$ 11
Subsequent Event | Series D Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.37
Subsequent Event | Series E Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,500
Preferred stock cash dividend	$ 11
Subsequent Event | Series E Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.38
Subsequent Event | Series F Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 2,625
Preferred stock cash dividend	$ 20
Subsequent Event | Series F Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 26.25
Subsequent Event | Series G Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,338
Preferred stock cash dividend	$ 7
Subsequent Event | Series G Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.33

Shareholders' Equity - Sched109

Shareholders' Equity - Schedule of Shares Repurchase Plans (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2016
Equity, Class of Treasury Stock [Line Items]
Shares Purchased		16.8
Average Cost per Share (USD per share)		$ 86.37
Total Purchased		$ 1,450,000,000
2017 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase			$ 1,400,000,000
Shares Purchased		7.4
Average Cost per Share (USD per share)		$ 94.54
Total Purchased		$ 700,000,000
2016 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase				$ 1,400,000,000
Shares Purchased		9.4
Average Cost per Share (USD per share)		$ 79.93
Total Purchased		$ 750,000,000
Boston Financial Data Services, Inc. and International Financial Data Services
Equity, Class of Treasury Stock [Line Items]
Common stock received in acquisition	$ 158,000,000

Shareholders' Equity - Sched110

Shareholders' Equity - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Net unrealized gains (losses) on cash flow hedges	$ (56)	$ 229	$ 293
Net unrealized gains (losses) on available-for-sale securities portfolio	148	(225)	9
Net unrealized gains (losses) related to reclassified available-for-sale securities	19	25	(28)
Net unrealized gains (losses) on available-for-sale securities	167	(200)	(19)
Net unrealized losses on available-for-sale securities designated in fair value hedges	(64)	(86)	(109)
Net unrealized gains (losses) on hedges of net investments in non-U.S. subsidiaries	(65)	95	(14)
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	(6)	(9)	(16)
Net unrealized losses on retirement plans	(170)	(194)	(183)
Foreign currency translation	(815)	(1,875)	(1,394)
Total	$ (1,009)	$ (2,040)	$ (1,442)

Shareholders' Equity - Accumula

Shareholders' Equity - Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 21,219	$ 21,103	$ 21,328
Other comprehensive income (loss)			(935)
Ending balance	22,317	21,219	21,103
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,040)	(1,442)	(507)
Other comprehensive income (loss) before reclassifications	1,029	(589)
Amounts reclassified into (out of) earnings	2	(9)
Other comprehensive income (loss)	1,031	(598)	(935)
Ending balance	(1,009)	(2,040)	(1,442)
Net Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	229	293
Other comprehensive income (loss) before reclassifications	(285)	(64)
Amounts reclassified into (out of) earnings	0	0
Other comprehensive income (loss)	(285)	(64)
Ending balance	(56)	229	293
Net Unrealized Gains (Losses) on Available-for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(286)	(128)
Other comprehensive income (loss) before reclassifications	412	(164)
Amounts reclassified into (out of) earnings	(23)	6
Other comprehensive income (loss)	389	(158)
Ending balance	103	(286)	(128)
Net Unrealized Losses on Hedges of Net Investments in Non-U.S. Subsidiaries
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	95	(14)
Other comprehensive income (loss) before reclassifications	(160)	109
Amounts reclassified into (out of) earnings	0	0
Other comprehensive income (loss)	(160)	109
Ending balance	(65)	95	(14)
Other-Than-Temporary Impairment on Held-to-Maturity Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(9)	(16)
Other comprehensive income (loss) before reclassifications	3	8
Amounts reclassified into (out of) earnings	0	(1)
Other comprehensive income (loss)	3	7
Ending balance	(6)	(9)	(16)
Net Unrealized Losses on Retirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(194)	(183)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified into (out of) earnings	24	(11)
Other comprehensive income (loss)	24	(11)
Ending balance	(170)	(194)	(183)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,875)	(1,394)
Other comprehensive income (loss) before reclassifications	1,059	(478)
Amounts reclassified into (out of) earnings	1	(3)
Other comprehensive income (loss)	1,060	(481)
Ending balance	$ (815)	$ (1,875)	$ (1,394)

Shareholders' Equity - Adjustme

Shareholders' Equity - Adjustments to Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Sales of non-U.S. entities, net of related taxes	$ 900	$ (372)	$ (735)
Total reclassifications (out of) into AOCI	2	(9)
Reclassification out of Accumulated Other Comprehensive Income | Net Unrealized Gains (Losses) on Available-for-Sale Securities
Class of Stock [Line Items]
Net realized gains (losses) from sales of available-for-sale securities, net of related taxes	(23)	6
Net realized gains from sales of available-for-sale securities, taxes	16	(4)
Reclassification out of Accumulated Other Comprehensive Income | Other-Than-Temporary Impairment on Securities
Class of Stock [Line Items]
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	0	(1)
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, taxes	0	1
Reclassification out of Accumulated Other Comprehensive Income | Amortization of Actuarial Losses
Class of Stock [Line Items]
Amortization of actuarial losses, net of related taxes	24	(11)
Amortization of actuarial losses, taxes	(8)	(1)
Reclassification out of Accumulated Other Comprehensive Income | Foreign Currency Translation
Class of Stock [Line Items]
Sales of non-U.S. entities, net of related taxes	1	(3)
Sale of non-U.S. entities, taxes	$ 0	$ (2)

Regulatory Capital (Details)

Regulatory Capital (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	$ 18,856	$ 17,459
Capital ratio: required common equity tier 1 capital	6.50%	5.50%
Capital ratio: required tier 1 capital	8.00%	7.00%
Capital ratio: required total capital	10.00%	9.00%
Capital ratio: required tier 1 leverage	4.00%	4.00%
Percentage of goodwill and other intangible assets net of associated deferred tax liabilities allocated to other intangible assets	80.00%	60.00%
Basel III Advanced Approaches
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 10,302	$ 10,286
Retained earnings	18,856	17,459
Accumulated other comprehensive income (loss)	(972)	(1,936)
Treasury stock, at cost	(9,029)	(7,682)
Total	19,157	18,127
Goodwill and other intangible assets, net of associated deferred tax liabilities	(6,877)	(6,348)
Other adjustments	(76)	(155)
Common equity tier 1 capital	12,204	11,624
Preferred stock	3,196	3,196
Trust preferred capital securities subject to phase-out from tier 1 capital	0	0
Other adjustments	(18)	(103)
Tier 1 capital	15,382	14,717
Qualifying subordinated long-term debt	980	1,172
Trust preferred capital securities phased out of tier 1 capital	0	0
ALLL and other	4	19
Other adjustments	1	1
Total capital	16,367	15,909
Credit risk	49,976	50,900
Operational risk(4)	45,822	44,579
Market risk	3,358	3,822
Total risk-weighted assets	99,156	99,301
Adjusted quarterly average assets	$ 209,328	$ 226,310
Common equity tier 1 capital	12.30%	11.70%
Tier 1 capital	15.50%	14.80%
Total capital	16.50%	16.00%
Tier 1 leveraged	7.30%	6.50%
Basel III Standardized Approach
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 10,302	$ 10,286
Retained earnings	18,856	17,459
Accumulated other comprehensive income (loss)	(972)	(1,936)
Treasury stock, at cost	(9,029)	(7,682)
Total	19,157	18,127
Goodwill and other intangible assets, net of associated deferred tax liabilities	(6,877)	(6,348)
Other adjustments	(76)	(155)
Common equity tier 1 capital	12,204	11,624
Preferred stock	3,196	3,196
Trust preferred capital securities subject to phase-out from tier 1 capital	0	0
Other adjustments	(18)	(103)
Tier 1 capital	15,382	14,717
Qualifying subordinated long-term debt	980	1,172
Trust preferred capital securities phased out of tier 1 capital	0	0
ALLL and other	72	77
Other adjustments	1	1
Total capital	16,435	15,967
Credit risk	101,349	98,125
Market risk	1,334	1,751
Total risk-weighted assets	102,683	99,876
Adjusted quarterly average assets	$ 209,328	$ 226,310
Common equity tier 1 capital	11.90%	11.60%
Tier 1 capital	15.00%	14.70%
Total capital	16.00%	16.00%
Tier 1 leveraged	7.30%	6.50%
State Street Bank | Basel III Advanced Approaches
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 11,612	$ 11,376
Retained earnings	12,312	12,285
Accumulated other comprehensive income (loss)	(809)	(1,648)
Treasury stock, at cost	0	0
Total	23,115	22,013
Goodwill and other intangible assets, net of associated deferred tax liabilities	(6,579)	(6,060)
Other adjustments	(5)	(148)
Common equity tier 1 capital	16,531	15,805
Preferred stock	0	0
Trust preferred capital securities subject to phase-out from tier 1 capital	0	0
Other adjustments	0	0
Tier 1 capital	16,531	15,805
Qualifying subordinated long-term debt	983	1,179
Trust preferred capital securities phased out of tier 1 capital	0	0
ALLL and other	0	15
Other adjustments	0	0
Total capital	17,514	16,999
Credit risk	47,448	47,383
Operational risk(4)	45,295	44,043
Market risk	3,375	3,822
Total risk-weighted assets	96,118	95,248
Adjusted quarterly average assets	$ 206,070	$ 222,584
Common equity tier 1 capital	17.20%	16.60%
Tier 1 capital	17.20%	16.60%
Total capital	18.20%	17.80%
Tier 1 leveraged	8.00%	7.10%
State Street Bank | Basel III Standardized Approach
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 11,612	$ 11,376
Retained earnings	12,312	12,285
Accumulated other comprehensive income (loss)	(809)	(1,648)
Treasury stock, at cost	0	0
Total	23,115	22,013
Goodwill and other intangible assets, net of associated deferred tax liabilities	(6,579)	(6,060)
Other adjustments	(5)	(148)
Common equity tier 1 capital	16,531	15,805
Preferred stock	0	0
Trust preferred capital securities subject to phase-out from tier 1 capital	0	0
Other adjustments	0	0
Tier 1 capital	16,531	15,805
Qualifying subordinated long-term debt	983	1,179
Trust preferred capital securities phased out of tier 1 capital	0	0
ALLL and other	72	77
Other adjustments	0	0
Total capital	17,586	17,061
Credit risk	98,433	94,413
Market risk	1,334	1,751
Total risk-weighted assets	99,767	96,164
Adjusted quarterly average assets	$ 206,070	$ 222,584
Common equity tier 1 capital	16.60%	16.40%
Tier 1 capital	16.60%	16.40%
Total capital	17.60%	17.70%
Tier 1 leveraged	8.00%	7.10%

Net Interest Income - Component

Net Interest Income - Components of Interest Revenue and Interest Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Banking and Thrift [Abstract]
Deposits with banks	$ 180	$ 126	$ 208
U.S. Treasury and federal agencies	854	821	735
State and political subdivisions	226	224	227
Other investments	658	756	934
Securities purchased under resale agreements	264	146	62
Loans and leases	504	378	311
Other interest-earning assets	222	61	11
Total interest income	2,908	2,512	2,488
Deposits	163	85	97
Securities sold under repurchase agreements	2	1	0
Short-term borrowings	10	7	7
Long-term debt	308	260	250
Other interest-bearing liabilities	121	75	46
Total interest expense	604	428	400
Net interest income	$ 2,304	$ 2,084	$ 2,088

Equity-Based Compensation - Nar

Equity-Based Compensation - Narrative (Details) - USD ($)	7 Months Ended	12 Months Ended			84 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	May 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded, but not delivered, available for reissue	1,000,000	1,000,000
Shares available for grant	25,900,000	25,900,000
Options granted (in shares)					0
Options outstanding (in shares)	0	0
Allocated share-based compensation		$ 243,000,000	$ 268,000,000	$ 319,000,000
Accelerated recognition due to restructuring plan		$ 15,000,000	$ 9,000,000	$ 10,000,000
Stock Options and SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	0	0	955,000	1,206,000	955,000
Intrinsic value of exercises in period		$ 5,000,000	$ 1,000,000	$ 5,000,000
Unrecognized share-based compensation expense for stock options	$ 0	$ 0
Stock Options and SARs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
Stock Options and SARs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		10 years
Restricted Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
Deferred Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		2,977,000	4,336,000
Fair value for vested in period		$ 232,000,000	$ 275,000,000	340,000,000
Costs not yet recognized	242,000,000	$ 242,000,000
Granted (in USD per share)		$ 76.38	$ 52.49
Period of recognition for unrecognized share-based compensation		2 years 5 months 24 days
Deferred Stock Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		1 year
Deferred Stock Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		534,000	506,000
Fair value for vested in period		$ 14,000,000	$ 21,000,000	$ 39,000,000
Costs not yet recognized	$ 16,000,000	$ 16,000,000
Granted (in USD per share)		$ 76.27	$ 50.81
Period of recognition for unrecognized share-based compensation		2 years 9 months 18 days
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
2017 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance						8,300,000
Additional shares authorized	17,900,000
Shares issued during period		0
2006 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance						28,500,000
Shares issued during period		68,900,000	65,700,000	60,900,000

Equity-Based Compensation - Sto

Equity-Based Compensation - Stock Options and Stock Appreciation Rights (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Shares
End of Period (in shares)	0
Stock Options and SARs
Shares
Beginning of Period (in shares)	955,000	1,206,000
Exercised (in shares)	(595,000)	(227,000)
Forfeited or Expired (in shares)	(360,000)	(24,000)
End of Period (in shares)	0	955,000
Weighted-Average Exercise Price
Beginning of Period (in USD per share)	$ 77.52	$ 76.29
Exercised (in USD per share)	81.71	70.59
Forfeited or Expired (in USD per share)	70.59	81.71
End of Period (in USD per share)	$ 0	$ 77.52
Weighted average contractual term of options outstanding	0 days
Total Intrinsic Value	$ 0

Equity-Based Compensation - Def

Equity-Based Compensation - Deferred Stock Awards (Details) - Deferred Stock Awards - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Shares
Beginning of Period (in shares)	7,814	8,736
Granted (in shares)	2,977	4,336
Vested (in shares)	(3,686)	(4,897)
Forfeited or Expired (in shares)	(257)	(361)
End of Period (in shares)	6,848	7,814
Weighted-Average Grant Date Fair Value
Beginning of Period (in USD per share)	$ 60.01	$ 61.59
Granted (in USD per share)	76.38	52.49
Vested (in USD per share)	62.88	56.18
Forfeited or Expired (in USD per share)	63.56	60.12
End of Period (in USD per share)	$ 65.44	$ 60.01

Equity-Based Compensation - Per

Equity-Based Compensation - Performance Awards (Details) - Performance Shares - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Shares
Beginning of Period (in shares)	1,247	1,165
Granted (in shares)	534	506
Forfeited or Expired (in shares)	0	0
Paid Out (in shares)	(233)	(424)
End of Period (in shares)	1,548	1,247
Weighted-Average Grant Date Fair Value
Beginning of Period (in USD per share)	$ 60.37	$ 60.45
Granted (in USD per share)	76.27	50.81
Forfeited or Expired (in USD per share)	0	0
Paid Out (in USD per share)	58.91	49.27
End of Period (in USD per share)	$ 66.09	$ 60.37

Employee Benefits - Narrative (

Employee Benefits - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit expense	$ 15	$ 16	$ 46
Contributions by employer	$ 146	132	$ 130
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Number of eligible employees for pension plan (in employee)	0
Defined benefit obligation	$ 1,320	1,230
Defined benefit underfunded status	9	32
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit obligation	16	21
Defined benefit underfunded status	16	21
SERP
Defined Benefit Plan Disclosure [Line Items]
Defined benefit obligation	125	136
Defined benefit underfunded status	$ 125	$ 136

Occupancy Expense and Inform120

Occupancy Expense and Information Systems and Communications Expense - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)ft²	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Occupancy Expense and Information Systems and Communications Expense [Abstract]
Depreciation	$ 526	$ 472	$ 443
Property Subject to or Available for Operating Lease [Line Items]
Capital lease obligation	159	194
Interest expense on capital lease	20	22	32
Accumulated amortization on capital lease	401	365
Sublease rental expense	229	194	190
Sublease revenue	5	$ 4	$ 4
Future minimum sublease rental revenue on capital lease	41
Future minimum sublease rental revenue on operating lease	$ 19
One Lincoln Street
Property Subject to or Available for Operating Lease [Line Items]
Leased area (in sqft) | ft²	1,025,000
Noncancelable capital leases expiration	20 years
Sublease building (in sqft) | ft²	127,000

Occupancy Expense and Inform121

Occupancy Expense and Information Systems and Communications Expense - Summary of Future Minimum Lease Payments Under Non-Cancelable Capital and Operating Leases (Details) $ in Millions	Dec. 31, 2017USD ($)
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Capital leases due 2018	$ 53
Capital leases due 2019	45
Capital leases due 2020	45
Capital leases due 2021	45
Capital leases due 2022	45
Capital leases due thereafter	34
Capital leases due	267
Less amount representing interest payments	(56)
Present value of minimum lease payments	211
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating leases due 2018	197
Operating leases due 2019	175
Operating leases due 2020	154
Operating leases due 2021	144
Operating leases due 2022	125
Operating leases due thereafter	336
Operating leases due	1,131
Total operating and capital leases due 2018	250
Total operating and capital leases due 2019	220
Total operating and capital leases due 2020	199
Total operating and capital leases due 2021	189
Total operating and capital leases due 2022	170
Total operating and capital leases due thereafter	370
Total operating and capital leases due	$ 1,398

Expenses - Schedule of Expenses

Expenses - Schedule of Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Expenses [Abstract]
Insurance	$ 118	$ 93	$ 126
Regulatory fees and assessments	106	82	115
Bank operations	80	62	105
Sales advertising public relations	67	52	65
Litigation	(15)	50	422
Other	233	245	185
Total other expenses	$ 589	$ 584	$ 1,018

Expenses - Narrative (Details)

Expenses - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Other Income and Expenses [Abstract]
Restructuring charges	$ 245	$ 142

Expenses - Restructuring Reserv

Expenses - Restructuring Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning balance	$ 56	$ 23	$ 69
Accruals	245	142
Payments and Other Adjustments	(100)	(107)	(51)
Ending balance	201	56	23
Employee Related Costs
Restructuring Reserve [Roll Forward]
Beginning balance	37	9	39
Payments and Other Adjustments	(57)	(64)	(25)
Ending balance	166	37	9
Real Estate Actions
Restructuring Reserve [Roll Forward]
Beginning balance	17	11	23
Payments and Other Adjustments	(17)	(12)	(9)
Ending balance	32	17	11
Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Beginning balance	2	3	7
Payments and Other Adjustments	(26)	(31)	(17)
Ending balance	3	2	3
Business Operations and IT
Restructuring Reserve [Roll Forward]
Accruals		(2)	5
Business Operations and IT | Employee Related Costs
Restructuring Reserve [Roll Forward]
Accruals		(2)	(5)
Business Operations and IT | Real Estate Actions
Restructuring Reserve [Roll Forward]
Accruals		0	(3)
Business Operations and IT | Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Accruals		0	$ 13
State Street Beacon
Restructuring Reserve [Roll Forward]
Accruals	245	142
State Street Beacon | Employee Related Costs
Restructuring Reserve [Roll Forward]
Accruals	186	94
State Street Beacon | Real Estate Actions
Restructuring Reserve [Roll Forward]
Accruals	32	18
State Street Beacon | Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Accruals	$ 27	$ 30

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 229	$ (14)	$ 52
State	18	30	92
Non-U.S.	380	320	342
Total current expense	627	336	486
Deferred:
Federal	49	(311)	(39)
State	65	38	40
Non-U.S.	(19)	(85)	(169)
Total deferred expense (benefit)	95	(358)	(168)
Total income tax expense (benefit)	$ 722	$ (22)	$ 318

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of the U.S. Statutory Income Tax Rate to the Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal income tax rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	1.90%	2.00%	4.20%
Tax-exempt income	(4.50%)	(6.10%)	(5.60%)
Business tax credits(1)	(6.80%)	(13.60%)	(9.40%)
Foreign tax differential	(7.40%)	(7.70%)	(9.60%)
Transition tax	15.70%	0.00%	0.00%
Deferred tax revaluation	(6.80%)	0.00%	0.00%
Foreign designated earnings	(0.70%)	(4.30%)	(0.00%)
Foreign capital transactions	(0.00%)	(6.80%)	(0.00%)
Tax refund	0.00%	0.00%	(2.80%)
Litigation expense	0.00%	1.40%	2.70%
Other, net	(1.50%)	(0.90%)	(0.70%)
Effective tax rate	24.90%	(1.00%)	13.80%

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred tax benefit due to revaluation of deferred tax assets	$ 197
Provisional transition tax expense	454
Unrecognized tax benefits	94	$ 71	$ 63	$ 163
Unrecognized tax benefits that would impact effective tax rate	87	63	55
Maximum estimated income tax expense change in unrecognized tax benefit in the next 12 months	14
Interest expense for tax examination	3	2
Interest accrued for tax examination	$ 8	$ 5	$ 3

Income Taxes - Schedule of C128

Income Taxes - Schedule of Components of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Unrealized losses on investment securities, net	$ 17	$ 157
Deferred compensation	159	285
Defined benefit pension plan	82	116
Restructuring charges and other reserves	132	199
Foreign currency translation	18	225
General business credit	231	425
NOL and other carryforwards	101	73
Other	27	32
Total deferred tax assets	767	1,512
Valuation allowance for deferred tax assets	(88)	(66)
Deferred tax assets, net of valuation allowance	679	1,446
Deferred tax liabilities:
Leveraged lease financing	184	313
Fixed and intangible assets	755	886
Non-U.S. earnings	6	164
Investment basis differences	158	120
Total deferred tax liabilities	$ 1,103	$ 1,483

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Asset Valuation Allowances (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Valuation Allowance	$ (88)	$ (66)
General business Credits
Valuation Allowance [Line Items]
General business Credits	231
Valuation Allowance	0
NOLs - Non-U.S.
Valuation Allowance [Line Items]
NOLs - Non-U.S.	47
Valuation Allowance	(35)
Other Carryforwards
Valuation Allowance [Line Items]
Other Carryforwards	41
Valuation Allowance	(41)
NOLs - State
Valuation Allowance [Line Items]
NOLs - State	13
Valuation Allowance	$ (12)

Income Taxes - Summary of Activ

Income Taxes - Summary of Activity Related to Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 71	$ 63	$ 163
Decrease related to agreements with tax authorities	(14)	(13)	(122)
Increase related to tax positions taken during current year	26	7	8
Increase related to tax positions taken during prior year	11	14	14
Ending balance	$ 94	$ 71	$ 63

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income	$ 2,177	$ 2,143	$ 1,980
Preferred stock dividends	(182)	(173)	(130)
Dividends and undistributed earnings allocated to participating securities	(2)	(2)	(2)
Net income available to common shareholders	$ 1,993	$ 1,968	$ 1,848
Basic average common shares	374,793	391,485	407,856
Effect of dilutive securities: common stock options and common stock awards (in shares)	5,420	4,605	5,782
Diluted average common shares	380,213	396,090	413,638
Anti-dilutive securities (in shares)	188	2,143	661
Earnings per Common Share:
Basic (in USD per share)	$ 5.32	$ 5.03	$ 4.53
Diluted (in USD per share)	$ 5.24	$ 4.97	$ 4.47

Line of Business Information -

Line of Business Information - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2017segment	Dec. 31, 2017	Dec. 31, 2017line_of_business	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting [Abstract]
Number of lines of business		2		2
Segment Reporting Information [Line Items]
Acquisition and restructuring costs	$ 266				$ 209	$ 25
Total expenses	8,269				8,077	8,050
Minimum | Investment Servicing and Management Services [Member] | Investment Servicing and Investment Management [Member]
Segment Reporting Information [Line Items]
Percentage of consolidated revenues by segment			75.00%
Minimum | Processing and Other Services [Member] | Investment Servicing and Investment Management [Member]
Segment Reporting Information [Line Items]
Percentage of consolidated revenues by segment			20.00%
Maximum | Investment Servicing and Management Services [Member] | Investment Servicing and Investment Management [Member]
Segment Reporting Information [Line Items]
Percentage of consolidated revenues by segment			80.00%
Maximum | Processing and Other Services [Member] | Investment Servicing and Investment Management [Member]
Segment Reporting Information [Line Items]
Percentage of consolidated revenues by segment			25.00%
Other
Segment Reporting Information [Line Items]
Acquisition and restructuring costs	266				209	25
Severance costs					(10)	73
Total expenses	$ 266				$ 199	$ 98

Line of Business Information133

Line of Business Information - Summary of Line of Business (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Servicing fees	$ 5,365	$ 5,073	$ 5,153
Management fees	1,616	1,292	1,174
Trading services	1,071	1,099	1,146
Securities finance	606	562	496
Processing fees and other	247	90	309
Total fee revenue	8,905	8,116	8,278
Net interest income	2,304	2,084	2,088
Gains (losses) related to investment securities, net	(39)	7	(6)
Total revenue	11,170	10,207	10,360
Provision for loan losses	2	10	12
Total expenses	8,269	8,077	8,050
Income before income tax expense (benefit)	$ 2,899	$ 2,120	$ 2,298
Pre-tax margin	26.00%	21.00%	22.00%
Total Average Assets	$ 219,400	$ 229,700	$ 250,500
Operating Segments | Investment Servicing
Segment Reporting Information [Line Items]
Servicing fees	5,365	5,073	5,153
Management fees	0	0	0
Trading services	999	1,038	1,091
Securities finance	606	562	496
Processing fees and other	240	119	342
Total fee revenue	7,210	6,792	7,082
Net interest income	2,309	2,081	2,086
Gains (losses) related to investment securities, net	(39)	7	(6)
Total revenue	9,480	8,880	9,162
Provision for loan losses	2	10	12
Total expenses	6,717	6,660	6,990
Income before income tax expense (benefit)	$ 2,761	$ 2,210	$ 2,160
Pre-tax margin	29.00%	25.00%	24.00%
Total Average Assets	$ 214,000	$ 225,300	$ 246,600
Operating Segments | Investment Management
Segment Reporting Information [Line Items]
Servicing fees	0	0	0
Management fees	1,616	1,292	1,174
Trading services	72	61	55
Securities finance	0	0	0
Processing fees and other	7	(29)	(33)
Total fee revenue	1,695	1,324	1,196
Net interest income	(5)	3	2
Gains (losses) related to investment securities, net	0	0	0
Total revenue	1,690	1,327	1,198
Provision for loan losses	0	0	0
Total expenses	1,286	1,218	962
Income before income tax expense (benefit)	$ 404	$ 109	$ 236
Pre-tax margin	24.00%	8.00%	20.00%
Total Average Assets	$ 5,400	$ 4,400	$ 3,900
Other
Segment Reporting Information [Line Items]
Servicing fees	0	0	0
Management fees	0	0	0
Trading services	0	0	0
Securities finance	0	0	0
Processing fees and other	0	0	0
Total fee revenue	0	0	0
Net interest income	0	0	0
Gains (losses) related to investment securities, net	0	0	0
Total revenue	0	0	0
Provision for loan losses	0	0	0
Total expenses	266	199	98
Income before income tax expense (benefit)	$ (266)	$ (199)	$ (98)

Non-U.S. Activities - Narrative

Non-U.S. Activities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 11,170	$ 10,207	$ 10,360
Assets	238,425	242,698
U.K.
Segment Reporting Information [Line Items]
Revenues	1,050	1,050	938
Non-U.S.
Segment Reporting Information [Line Items]
Revenues	4,734	4,419	$ 4,428
Assets	$ 82,100	$ 79,100

Non-U.S. Activities - Schedule

Non-U.S. Activities - Schedule Of Results From Non-U.S. Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenue	$ 11,170	$ 10,207	$ 10,360
Income before income taxes	2,899	2,120	2,298
Non-U.S.
Segment Reporting Information [Line Items]
Total revenue	4,734	4,419	4,428
Income before income taxes	1,230	1,047	1,193
U.S.
Segment Reporting Information [Line Items]
Total revenue	6,436	5,788	5,932
Income before income taxes	$ 1,669	$ 1,073	$ 1,105

Parent Company Financial Sta136

Parent Company Financial Statements - Statement of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Total revenue	$ 11,170	$ 10,207	$ 10,360
Other expenses	589	584	1,018
Total expenses	8,269	8,077	8,050
Income tax expense (benefit)	722	(22)	318
Net income	2,177	2,143	1,980
Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash dividends from consolidated banking subsidiary	2,224	640	585
Cash dividends from consolidated non-banking subsidiaries and unconsolidated entities	12	75	171
Other, net	127	92	73
Total revenue	2,363	807	829
Interest expense	297	249	209
Other expenses	94	107	310
Total expenses	391	356	519
Income tax expense (benefit)	(86)	(47)	(186)
Income before equity in undistributed income of consolidated subsidiaries and unconsolidated entities	2,058	498	496
Consolidated banking subsidiary	20	1,629	1,384
Consolidated non-banking subsidiaries and unconsolidated entities	99	16	100
Net income	$ 2,177	$ 2,143	$ 1,980

Parent Company Financial Sta137

Parent Company Financial Statements - Statement of Condition (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Interest-bearing deposits with banks	$ 67,227	$ 70,935
Trading account assets	1,093	1,024
Investment securities available-for-sale	57,121	61,998
Other assets	31,018	38,328
Total assets	238,425	242,698
Liabilities:
Total liabilities	216,108	221,479
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Shareholders’ equity	22,317	21,219	$ 21,103	$ 21,328
Total liabilities and shareholders' equity	238,425	242,698
Parent Company
Assets:
Interest-bearing deposits with banks	532	3,635
Trading account assets	361	325
Investment securities available-for-sale	43	39
Consolidated banking subsidiary	23,080	22,147
Consolidated non-banking subsidiaries	6,762	2,687
Unconsolidated entities	63	297
Consolidated banking subsidiary	2,973	2,743
Consolidated non-banking subsidiaries and unconsolidated entities	143	126
Other assets	263	461
Total assets	34,220	32,460
Liabilities:
Accrued expenses and other liabilities	917	514
Long-term debt	10,986	10,727
Total liabilities	11,903	11,241
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Shareholders’ equity	22,317	21,219
Total liabilities and shareholders' equity	$ 34,220	$ 32,460

Parent Company Financial Sta138

Parent Company Financial Statements - Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities:
Net cash provided by operating activities	$ 6,933	$ 2,290	$ (1,403)
Investing Activities:
Net decrease (increase) in interest-bearing deposits with consolidated banking subsidiary	3,708	4,403	18,185
Business acquisitions	0	(437)	0
Net cash provided by investing activities	48	4,230	24,995
Financing Activities:
Proceeds from issuance of long-term debt, net of issuance costs	747	1,492	2,983
Payments for long-term debt	(493)	(1,441)	(1,155)
Proceeds from issuance of preferred stock, net	0	493	742
Proceeds from exercises of common stock options	0	0	4
Purchases of common stock	(1,292)	(1,365)	(1,520)
Repurchases of common stock for employee tax withholding	(126)	(122)	(222)
Payments for cash dividends	(768)	(723)	(655)
Net cash (used in) financing activities	(6,188)	(6,413)	(24,240)
Net increase (decrease)	793	107	(648)
Cash and due from banks at beginning of period	1,314	1,207	1,855
Cash and due from banks at end of period	2,107	1,314	1,207
Parent Company
Operating Activities:
Net cash provided by operating activities	2,047	417	926
Investing Activities:
Net decrease (increase) in interest-bearing deposits with consolidated banking subsidiary	3,103	2,100	295
Investments in consolidated banking and non-banking subsidiaries	(7,672)	(7,600)	(7,959)
Sale or repayment of investment in consolidated banking and non-banking subsidiaries	4,216	6,703	7,891
Business acquisitions	0	(395)	0
Net increase in investments in unconsolidated affiliates	172	0	0
Net cash provided by investing activities	(181)	808	227
Financing Activities:
Net increase (decrease) in commercial paper	0	0	(2,485)
Proceeds from issuance of long-term debt, net of issuance costs	748	1,492	2,983
Payments for long-term debt	(450)	(1,000)	0
Proceeds from issuance of preferred stock, net	0	493	742
Proceeds from exercises of common stock options	0	0	4
Purchases of common stock	(1,292)	(1,365)	(1,520)
Repurchases of common stock for employee tax withholding	(104)	(122)	(222)
Payments for cash dividends	(768)	(723)	(655)
Net cash (used in) financing activities	(1,866)	(1,225)	(1,153)
Net increase (decrease)	0	0	0
Cash and due from banks at beginning of period	0	0	0
Cash and due from banks at end of period	$ 0	$ 0	$ 0