State Street (STT) 10-Q 10 Nov 14 2014 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014
Document And Entity Information [Abstract]	'	'
Entity Registrant Name	'STATE STREET Corp	'
Entity Central Index Key	'0000093751	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	417,495,288

Consolidated_Statement_of_Inco

Consolidated Statement of Income (USD $)	3 Months Ended				9 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Fee revenue:	'		'		'		'
Servicing fees	$1,302		$1,211		$3,828		$3,587
Management fees	316		276		908		816
Trading services	278		265		791		858
Securities finance	99		74		331		283
Processing fees and other	17		57		117		167
Total fee revenue	2,012		1,883		5,975		5,711
Net interest revenue:	'		'		'		'
Interest revenue	671		643		1,976		2,030
Interest expense	101		97		290		312
Net interest revenue	570		546		1,686		1,718
Gains (losses) related to investment securities, net:	'		'		'		'
Net gains (losses) from sales of available-for-sale securities	0		6		15		11
Losses from other-than-temporary impairment	0		-13		-1		-19
Losses reclassified (from) to other comprehensive income	0		3		-10		-1
Gains (losses) related to investment securities, net	0		-4		4		-9
Total revenue	2,582		2,425		7,665		7,420
Provision for loan losses	2		0		6		0
Expenses:	'		'		'		'
Compensation and employee benefits	953		903		3,088		2,855
Information systems and communications	242		235		730		707
Transaction processing services	199		185		583		551
Occupancy	119		113		348		343
Acquisition and restructuring costs	20		30		81		74
Professional services	97		98		318		280
Amortization of other intangible assets	54		53		162		160
Other	208		105		460		376
Total expenses	1,892		1,722		5,770		5,346
Income before income tax expense	688		703		1,889		2,074
Income tax expense	128		163		344		491
Net income	560		540		1,545		1,583
Net income available to common shareholders	$542		$531		$1,500		$1,557
Earnings per common share:	'		'		'		'
Basic (in dollars per share)	$1.28		$1.20		$3.52		$3.46
Diluted (in dollars per share)	$1.26	[1]	$1.17	[1]	$3.45	[1]	$3.40	[1]
Average common shares outstanding	'		'		'		'
Basic (in shares)	421,974		442,860		426,775		449,742
Diluted (in shares)	429,736		452,154		434,510		458,392
Cash dividends declared (in dollars per share)	$0.30		$0.26		$0.86		$0.78
[1]	Calculations reflect allocation of earnings to participating securities using the two-class method, as this computation is more dilutive than the treasury stock method.

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$560	$540	$1,545	$1,583
Other comprehensive income (loss), net of related taxes:	'	'	'	'
Foreign currency translation, net of related taxes	-591	326	-518	23
Net unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment and net of related taxes	-140	111	425	-642
Net unrealized gains (losses) on available-for-sale securities designated in fair value hedges, net of related taxes	14	1	-9	61
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related taxes	4	3	16	14
Net unrealized gains (losses) on cash flow hedges, net of related taxes	117	-33	56	61
Net unrealized gains (losses) on retirement plans, net of related taxes	0	1	18	9
Other comprehensive income (loss)	-596	409	-12	-474
Total comprehensive income	($36)	$949	$1,533	$1,109

Consolidated_Statement_of_Comp1

Consolidated Statement of Comprehensive Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Foreign currency translation, taxes	($75)	$66	($38)	($27)
Change in net unrealized losses on available-for-sale securities, net of reclassification adjustment and taxes	-94	76	261	-402
Change in net unrealized losses on available-for-sale securities designated in fair value hedges, taxes	10	0	-5	40
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, taxes	2	1	10	8
Change in net unrealized losses on cash flow hedges, taxes	37	-21	34	38
Change in minimum pension liability, taxes	$3	$6	($2)	$12

Consolidated_Statement_of_Cond

Consolidated Statement of Condition (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Assets:	'	'
Cash and due from banks	$4,146	$3,220
Interest-bearing deposits with banks	86,946	64,257
Securities purchased under resale agreements	2,603	6,230
Trading account assets	1,033	843
Investment securities available for sale	96,552	99,174
Investment securities held to maturity (fair value of $18,865 and $17,560)	18,767	17,740
Loans and leases (less allowance for losses of $34 and $28)	18,364	13,458
Premises and equipment (net of accumulated depreciation of $4,538 and $4,417)	1,911	1,860
Accrued interest and fees receivable	2,318	2,123
Goodwill	5,899	6,036
Other intangible assets	2,121	2,360
Other assets	34,145	25,990
Total assets	274,805	243,291
Deposits:	'	'
Noninterest-bearing	66,134	65,614
Interest-bearing—U.S.	24,435	13,392
Interest-bearing—non-U.S.	117,399	103,262
Total deposits	207,968	182,268
Securities sold under repurchase agreements	9,385	7,953
Federal funds purchased	17	19
Other short-term borrowings	4,307	3,780
Accrued expenses and other liabilities	22,956	19,194
Long-term debt	9,016	9,699
Total liabilities	253,649	222,913
Commitments, guarantees and contingencies (notes 7 and 8)	'	'
Shareholders’ equity:	'	'
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding and Series D, 7,500 shares issued and outstanding	'	491	[1]
Common stock, $1 par: 750,000,000 shares authorized; 503,881,095 and 503,882,841 shares issued	504	504
Surplus	9,780	9,776
Retained earnings	14,531	13,395	[1]
Accumulated other comprehensive income (loss)	-107	-95
Treasury stock, at cost (83,948,535 and 69,754,255 shares)	-4,785	-3,693
Total shareholders’ equity	21,156	20,378
Total liabilities and shareholders’ equity	274,805	243,291
Series C Preferred Stock	'	'
Shareholders’ equity:	'	'
Preferred stock, no par: 3,500,000 shares authorized; Series C, 5,000 shares issued and outstanding and Series D, 7,500 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 and Series D, 7,500 shares issued and outstanding	$742	$0
[1]	Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of December 31, 2013 were calculated in conformity with the provisions of Basel I.

Consolidated_Statement_of_Cond1

Consolidated Statement of Condition (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Current Assets:	'	'
Investment securities held to maturity, fair value	$18,865	$17,560
Loans and leases, allowance for losses	34	28
Premises and equipment, accumulated depreciation	$4,538	$4,417
Stockholders' Equity:	'	'
Common stock, par value (in dollars per share)	$1	$1
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	503,880,120	503,882,841
Preferred stock, shares authorized (in shares)	3,500,000	3,500,000
Treasury stock, shares (in shares)	83,948,535	69,754,255
Series C Preferred Stock	'	'
Stockholders' Equity:	'	'
Preferred stock, shares issued, Series C (in shares)	5,000	5,000
Preferred stock, shares outstanding, Series C (in shares)	5,000	5,000
Series D Preferred Stock	'	'
Stockholders' Equity:	'	'
Preferred stock, shares issued, Series C (in shares)	7,500	'
Preferred stock, shares outstanding, Series C (in shares)	7,500	'

Consolidated_Statement_of_Chan

Consolidated Statement of Changes In Shareholders' Equity (USD $)	Total	PREFERRED STOCK	COMMON STOCK	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	TREASURY STOCK
In Millions, except Share data, unless otherwise specified
Beginning balance at Dec. 31, 2012	$20,869	$489	$504	$9,667	$11,751	$360	($1,902)
Beginning balance (shares) at Dec. 31, 2012	'	'	503,900,000	'	'	'	45,238,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	1,583	'	'	'	1,583	'	'
Other comprehensive income (loss)	-474	'	'	'	'	-474	'
Accretion of issuance costs	0	-1	'	'	-1	'	'
Cash dividends declared:	'	'	'	'	'	'	'
Common stock	-350	'	'	'	'	'	'
Preferred stock	-20	'	'	'	-20	'	'
Common stock acquired	-1,480	'	'	'	'	'	-1,480
Common stock acquired (shares)	'	'	'	'	'	'	23,235,000
Common stock awards and options exercised, including related taxes	302	'	'	86	'	'	216
Common stock awards and options exercised, including related taxes (shares)	'	'	-15,000	'	'	'	-5,874,000
Other	0	'	'	'	'	'	'
Other (shares)	'	'	'	'	'	'	-12,000
Ending balance at Sep. 30, 2013	20,430	490	504	9,753	12,963	-114	-3,166
Ending balance (shares) at Sep. 30, 2013	'	'	503,885,000	'	'	'	62,587,000
Beginning balance at Dec. 31, 2013	20,378	491	504	9,776	13,395	-95	-3,693
Beginning balance (shares) at Dec. 31, 2013	'	'	503,883,000	'	'	'	69,754,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income	1,545	'	'	'	1,545	'	'
Other comprehensive income (loss)	-12	'	'	'	'	-12	'
Preferred stock issued	742	742	'	'	'	'	'
Cash dividends declared:	'	'	'	'	'	'	'
Common stock	-366	'	'	'	'	'	'
Preferred stock	-43	'	'	'	-43	'	'
Common stock acquired	-1,240	'	'	'	'	'	-1,240
Common stock acquired (shares)	18,200,000	'	'	'	'	'	18,187,000
Common stock awards and options exercised, including related taxes	152	'	'	4	'	'	148
Common stock awards and options exercised, including related taxes (shares)	'	'	-3,000	'	'	'	-3,984,000
Other	0	'	'	'	'	'	'
Other (shares)	'	'	'	'	'	'	-8,000
Ending balance at Sep. 30, 2014	$21,156	$1,233	$504	$9,780	$14,531	($107)	($4,785)
Ending balance (shares) at Sep. 30, 2014	'	'	503,880,000	'	'	'	83,949,000

Consolidated_Statement_of_Chan1

Consolidated Statement of Changes In Shareholders' Equity (Unaudited) (Parenthetical) (USD $)	9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Statement of Stockholders' Equity [Abstract]	'	'
Cash dividends declared (in dollars per share)	$0.86	$0.78
Common stock awards and options exercised, related taxes	$54	$42

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating Activities:	'	'
Net income	$1,545	$1,583
Adjustments to reconcile net income to net cash provided by (used in) operating activities:	'	'
Deferred income tax (benefit) expense	-17	77
Amortization of other intangible assets	162	160
Other non-cash adjustments for depreciation, amortization and accretion, net	351	324
(Gains) losses related to investment securities, net	-4	9
Change in trading account assets, net	-190	-279
Change in accrued interest and fees receivable, net	-195	-124
Change in collateral deposits, net	-3,533	-2,765
Change in unrealized losses on foreign exchange derivatives, net	-2,316	1,304
Change in other assets, net	1,563	-888
Change in accrued expenses and other liabilities, net	1,430	-279
Other, net	240	303
Net cash used in operating activities	-964	-575
Investing Activities:	'	'
Net (increase) decrease in interest-bearing deposits with banks	-22,689	12,127
Net decrease (increase) in securities purchased under resale agreements	3,627	-811
Proceeds from sales of available-for-sale securities	8,205	8,090
Proceeds from maturities of available-for-sale securities	28,562	29,540
Purchases of available-for-sale securities	-35,393	-29,005
Proceeds from maturities of available-for-sale securities	2,383	1,474
Purchases of held-to-maturity securities	-3,271	-6,424
Net increase in loans	-4,927	-3,304
Purchases of equity investments and other long-term assets	-169	-100
Divestitures	0	18
Purchases of premises and equipment	-298	-259
Other, net	63	84
Net cash (used in) provided by investing activities	-23,907	11,430
Financing Activities:	'	'
Net increase (decrease) in time deposits	6,266	-14,750
Net increase in all other deposits	19,434	4,768
Net increase in short-term borrowings	1,957	967
Proceeds from issuance of long-term debt, net of issuance costs	0	1,492
Payments for long-term debt and obligations under capital leases	-779	-127
Proceeds from issuance of preferred stock	742	0
Proceeds from exercises of common stock options	10	109
Purchases of common stock	-1,240	-1,480
Repurchases of common stock for employee tax withholding	-197	-163
Payments for cash dividends	-396	-365
Net cash provided by (used in) financing activities	25,797	-9,549
Net increase	926	1,306
Cash and due from banks at beginning of period	3,220	2,590
Cash and due from banks at end of period	$4,146	$3,896

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The accounting and financial reporting policies of State Street Corporation conform to U.S. generally accepted accounting principles, referred to as 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. Our principal banking subsidiary is State Street Bank and Trust Company, or State Street Bank.
	We have two lines of business:
	Investment Servicing provides services for 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; record-keeping; cash management; foreign exchange, brokerage and other trading services; securities finance; deposit and short-term investment facilities; loans and lease financing; investment manager and alternative investment manager operations outsourcing; and performance, risk and compliance analytics to support institutional investors.
	Investment Management, through State Street Global Advisors, or SSgA, provides a broad array of investment management, investment research and investment advisory services to corporations, public funds and other sophisticated investors. SSgA offers active and passive asset management strategies across equity, fixed-income and cash asset classes. Products are distributed directly and through intermediaries using a variety of investment vehicles, including exchange-traded funds, or ETFs, such as the SPDR® ETF brand.
	The consolidated financial statements accompanying these condensed notes are unaudited. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the consolidated results of operations in these financial statements, have been made. Certain previously reported amounts presented in this Form 10-Q have been reclassified to conform to current-period presentation. Events occurring subsequent to the date of our consolidated statement of condition were evaluated for potential recognition or disclosure in our
	consolidated financial statements through the date we filed this Form 10-Q with the SEC.
	The preparation of consolidated financial statements in conformity with 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. Amounts dependent on subjective or complex judgments in the application of accounting policies considered by management to be relatively more significant in this regard are those associated with our accounting for recurring fair-value measurements; other-than-temporary impairment of investment securities; and impairment of goodwill and other intangible assets. Among other effects, unanticipated events or circumstances could result in future impairment of investment securities, goodwill or other intangible assets.
	Our consolidated statement of condition as of December 31, 2013 included in the accompanying consolidated financial statements was derived from the audited financial statements as of that date, but does not include all notes required by GAAP for a complete set of consolidated financial statements. The accompanying consolidated financial statements and these condensed notes should be read in conjunction with the financial and risk factors information included in our 2013 Annual Report on Form 10-K, which we previously filed with the SEC.
	Recent Accounting Developments:
	In August 2014, the FASB issued an amendment to GAAP that requires management to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern and, if so, disclose that fact. The amendment is effective, for State Street, for its annual consolidated financial statements as of December 31, 2016 and interim periods thereafter. Our adoption of the amendment will not have a material effect on our consolidated financial statements.
	In June 2014, the FASB issued an amendment to GAAP for “repo-to-maturity” transactions and repurchase agreements executed as repurchase financings. The amendment requires enhanced disclosure for repurchase agreements and securities lending transactions accounted for as secured borrowings and for certain transfers of financial assets. The amendment is effective, for State Street, beginning on January 1, 2015. Our adoption of the amendment is not expected to have a material effect on our consolidated financial statements.
	In May 2014, the FASB issued an amendment to GAAP that provides for a single comprehensive model to be applied in the accounting for revenue arising from contracts with clients. In applying this model, an entity would recognize revenue that represents the transfer of promised goods or services to clients in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendment supersedes most current revenue recognition guidance, including industry-specific guidance. The amendment is effective, for State Street, beginning on January 1, 2017, and must be applied retrospectively. Early adoption is prohibited. We are currently assessing the potential impact of this amendment on our consolidated financial statements.
	In April 2014, the FASB issued an amendment to GAAP that revises the criteria for the treatment and disclosure of discontinued operations. The amendment allows entities to have significant continuing involvement and continuing cash flows with the discontinued operation, but requires additional disclosure for discontinued operations and disclosure for disposals deemed to be material that do not meet the definition of a discontinued operation. The presentation and disclosure requirements are effective, for State Street, beginning on January 1, 2015, and are required to be applied prospectively to discontinued operations occurring after that date.
	In January 2014, the FASB issued an amendment to GAAP that allows an investor in an affordable housing project, if the project meets certain defined conditions, to amortize the cost of their investment in proportion to the tax credits and other tax benefits they receive, and reflect it as part of income tax expense rather than as revenue from operations. The amendment is effective, for State Street, for interim and annual periods beginning after December 15, 2014, with early adoption permitted, and must be applied retrospectively. At this time, we have not chosen to early-adopt the amendment as we continue to assess the potential impact of this amendment on our consolidated financial statements.

Fair_Value

Fair Value	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value	'
	Fair Value
	Fair-Value Measurements:
	We carry trading account assets, investment securities available for sale 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 accumulated other comprehensive income, or 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 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 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 most 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. Fair value is measured using unadjusted quoted prices in active markets for identical securities. 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 available-for-sale portfolio in connection with our asset-and-liability management activities. Our level-1 financial assets also include active exchange-traded equity securities and non-cash collateral received from counterparties in connection with our enhanced custody business.
	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 in the three and nine months ended September 30, 2014 or 2013, respectively.
	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 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.
	•	The fair value of certain interest-rate caps with long-dated maturities is measured using a matrix-pricing approach. Observable market prices are not available for these derivatives, so extrapolation is necessary to value these instruments, since they have a strike and/or maturity outside of the matrix.
	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. As of September 30, 2014, on a gross basis, we categorized in level 3 approximately 5% of our financial assets carried at fair value on a recurring basis. As of the same date and on the same basis, the percentage of our financial liabilities categorized in level 3 to our financial liabilities carried at fair value on a recurring basis was not significant. The fair value of investment securities categorized in level 3 that was measured using non-binding quotes and internally-developed pricing-model inputs composed approximately 98% and 2%, respectively, of the total fair value of our investment securities categorized in level 3 as of September 30, 2014.
	The process used to measure the fair value of our level-3 financial assets and liabilities is overseen by a valuation group within Corporate Finance, separate from the business units that manage the assets and liabilities. This function, which develops and manages the valuation process, reports to State Street's Valuation Committee. The Valuation Committee, composed of senior management from separate business units, Enterprise Risk Management, a corporate risk oversight group, and Corporate Finance, oversees adherence to State Street's valuation policies.
	The valuation group performs validation of the pricing information obtained from third-party sources in order to evaluate reasonableness and consistency with market experience in similar asset classes. Monthly analyses include a review of price changes relative to overall trends, credit analysis and other relevant procedures (discussed below). In addition, prices for level-3 securities carried in our investment portfolio are tested on a sample basis based on unexpected pricing movements. These sample prices are then corroborated through price recalculations, when applicable, using available market information, which is obtained separately from the third-party pricing source. The recalculated prices are compared to market-research information pertaining to credit expectations, execution prices and the timing of cash flows, and where information is available, back-testing. If a difference is identified and it is determined that there is a significant impact requiring an adjustment, the adjustment is presented to the Valuation Committee for review and consideration.
	Validation is also performed on fair-value measurements determined using internally-developed pricing models. The pricing models are subject to validation through our Model Assessment Committee, a corporate risk oversight committee that provides technical support and input to the Valuation Committee. This validation process incorporates a review of a diverse set of model and trade parameters across a broad range of values in order to evaluate the model's suitability for valuation of a particular financial instrument type, as well as the model's accuracy in reflecting the characteristics of the related financial asset or liability and its significant risks. Inputs and assumptions, including any price-valuation adjustments, are developed by the business units and separately reviewed by the valuation group. Model valuations are compared to available market information including appropriate proxy instruments and other benchmarks to highlight abnormalities for further investigation.
	Measuring fair value requires the exercise of management judgment. The level of subjectivity and the degree of management judgment required is more significant for financial instruments whose fair value is measured using inputs that are not observable. The areas requiring significant judgment are identified, documented and reported to the Valuation Committee as part of the valuation control framework. We believe that our valuation methods are appropriate; however, the use of different methodologies or assumptions, particularly as they apply to level-3 financial assets and liabilities, could materially affect our fair-value measurements as of the reporting date.
	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. No transfers of financial assets or liabilities between levels 1 and 2 occurred in the nine months ended September 30, 2014 or the year ended December 31, 2013.
		Fair-Value Measurements on a Recurring Basis
		as of September 30, 2014
	(In millions)	Quoted Market			Pricing Methods			Pricing Methods				Impact of Netting(1)			Total Net
		Prices in Active			with Significant			with Significant							Carrying Value
		Markets			Observable			Unobservable							in Consolidated
		(Level 1)			Market Inputs			Market Inputs							Statement of
					(Level 2)			(Level 3)							Condition
	Assets:
	Trading account assets:
	U.S. government securities	$	37		$	—		$	—						$	37
	Non-U.S. government securities	479			—			—							479
	Other	52			465			—							517
	Total trading account assets	568			465			—							1,033
	Investment securities available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	10,139			625			—							10,764
	Mortgage-backed securities	—			20,941			260							21,201
	Asset-backed securities:
	Student loans	—			12,540			266							12,806
	Credit cards	—			3,111			—							3,111
	Sub-prime	—			997			—							997
	Other	—			399			3,944							4,343
	Total asset-backed securities	—			17,047			4,210							21,257
	Non-U.S. debt securities:
	Mortgage-backed securities	—			10,239			—							10,239
	Asset-backed securities	—			3,023			424							3,447
	Government securities	—			3,613			—							3,613
	Other	—			5,551			298							5,849
	Total non-U.S. debt securities	—			22,426			722							23,148
	State and political subdivisions	—			10,604			41							10,645
	Collateralized mortgage obligations	—			4,437			234							4,671
	Other U.S. debt securities	—			4,276			8							4,284
	U.S. equity securities	—			38			—							38
	Non-U.S. equity securities	—			2			—							2
	U.S. money-market mutual funds	—			532			—							532
	Non-U.S. money-market mutual funds	—			10			—							10
	Total investment securities available for sale	10,139			80,938			5,475							96,552
	Other assets:
	Derivative instruments:
	Foreign exchange contracts	—			16,797			68				$	(8,162	)	8,703
Interest-rate contracts	—			63			—				(58		)	5
Other derivative contracts	—			4			—				—			4
Total derivative instruments	—			16,864			68				(8,220		)	8,712
Other	115			—			—				—			115
Total assets carried at fair value	$	10,822		$	98,267		$	5,543			$	(8,220	)	$	106,412
Liabilities:
Accrued expenses and other liabilities:
Trading account liabilities:
U.S. government securities	$	92		$	—		$	—			$	—		$	92
Non-U.S. government securities	50			—			—				—			50
Other	3			—			—				—			3
Derivative instruments:
Foreign exchange contracts	—			16,500			59				(9,911		)	$	6,648
Interest-rate contracts	—			241			—				(49		)	192
Other derivative contracts	—			64			9				—			73
Total derivative instruments	—			16,805			68				(9,960		)	6,913
Other	115			—			—				—			115
Total liabilities carried at fair value	$	260		$	16,805		$	68			$	(9,960	)	$	7,173
(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 $841 million and $2.58 billion, respectively, for cash collateral received from and provided to derivative counterparties.
	Fair-Value Measurements on a Recurring Basis
	as of December 31, 2013
(In millions)	Quoted Market			Pricing Methods			Pricing Methods				Impact of Netting(1)			Total Net
	Prices in Active			with Significant			with Significant							Carrying Value
	Markets			Observable			Unobservable							in Consolidated
	(Level 1)			Market Inputs			Market Inputs							Statement of
				(Level 2)			(Level 3)							Condition
Assets:
Trading account assets:
U.S. government securities	$	20		$	—		$	—						$	20
Non-U.S. government securities	399			—			—							399
Other	67			357			—							424
Total trading account assets	486			357			—							843
Investment securities available for sale:
U.S. Treasury and federal agencies:
Direct obligations	—			709			—							709
Mortgage-backed securities	—			22,847			716							23,563
Asset-backed securities:
Student loans	—			14,119			423							14,542
Credit cards	—			8,186			24							8,210
Sub-prime	—			1,203			—							1,203
Other	—			532			4,532							5,064
Total asset-backed securities	—			24,040			4,979							29,019
Non-U.S. debt securities:
Mortgage-backed securities	—			10,654			375							11,029
Asset-backed securities	—			4,592			798							5,390
Government securities	—			3,761			—							3,761
Other	—			4,263			464							4,727
Total non-U.S. debt securities	—			23,270			1,637							24,907
State and political subdivisions	—			10,220			43							10,263
Collateralized mortgage obligations	—			5,107			162							5,269
Other U.S. debt securities	—			4,972			8							4,980
U.S. equity securities	—			34			—							34
Non-U.S. equity securities	—			1			—							1
U.S. money-market mutual funds	—			422			—							422
Non-U.S. money-market mutual funds	—			7			—							7
Total investment securities available for sale	—			91,629			7,545							99,174
Other assets:
Derivatives instruments:
Foreign exchange contracts	—			11,892			19				$	(6,442	)	5,469
Interest-rate contracts	—			65			—				(59		)	6
Other derivative contracts	—			1			—				—			1
Total derivative instruments	—			11,958			19				(6,501		)	5,476
Other	97			—			—				—			97
Total assets carried at fair value	$	583		$	103,944		$	7,564			$	(6,501	)	$	105,590
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	—		$	11,454		$	17			$	(5,458	)	$	6,013
Interest-rate contracts	—			331			—				(94		)	237
Other derivative contracts	—			—			9				—			9
Total derivative instruments	—			11,785			26				(5,552		)	6,259
Other	97			—			—				—			97
Total liabilities carried at fair value	$	97		$	11,785		$	26			$	(5,552	)	$	6,356
(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 $1.93 billion and $979 million, respectively, for cash collateral received from and provided to derivative counterparties.
The following tables present activity related to our level-3 financial assets and liabilities during the three and nine months ended September 30, 2014 and 2013, respectively. Transfers into and out of level 3 are reported as of the beginning of the period presented. In the three and nine months ended September 30, 2014 and 2013, respectively, transfers out of level 3 were mainly related to certain mortgage- and asset-backed securities, 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
	Three Months Ended September 30, 2014
	Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	June 30,			Unrealized Gains (Losses)																			into		out of			30-Sep-14		Unrealized
	2014																						Level 3		Level 3					Gains
																														(Losses)
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2014
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies, mortgage-backed securities	$	96		$	—		$	—			$	168		$	—		$	—		$	(4	)	$	—	$	—		$	260
Asset-backed securities:
Student loans	322			—			(1		)		24			—			(74		)	(5		)	—		—			266
Other	4,061			18			(8		)		275			—			—			(402		)	—		—			3,944
Total asset-backed securities	4,383			18			(9		)		299			—			(74		)	(407		)	—		—			4,210
Non-U.S. debt securities:
Asset-backed securities	506			2			(1		)		—			—			—			(99		)	76		(60		)	424
Other	515			—			—				—			—			—			(25		)	—		(192		)	298
Total non-U.S. debt securities	1,021			2			(1		)		—			—			—			(124		)	76		(252		)	722
State and political subdivisions	41			—			—				—			—			—			—			—		—			41
Collateralized mortgage obligations	196			—			—				125			—			—			(7		)	—		(80		)	234
Other U.S. debt securities	9			—			—				—			—			—			(1		)	—		—			8
Total investment securities available for sale	5,746			20			(10		)		592			—			(74		)	(543		)	76		(332		)	5,475
Other assets:
Derivative instruments:
Derivative instruments, Foreign exchange contracts	10			44			—				22			—			—			(8		)	—		—			68		$	40
Total derivative instruments	10			44			—				22			—			—			(8		)	—		—			68		40
Total assets carried at fair value	$	5,756		$	64		$	(10	)		$	614		$	—		$	(74	)	$	(551	)	$	76	$	(332	)	$	5,543	$	40
	Fair-Value Measurements Using Significant Unobservable Inputs
	Three Months Ended September 30, 2014
	Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	June 30,			Unrealized (Gains) Losses																			into		out of			30-Sep-14		Unrealized
	2014																						Level 3		Level 3					(Gains)
																														Losses Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2014
				in			in Other
				Revenue			Comprehensive
							Income
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	10		$	36		$	—			$	—		$	18		$	—		$	(5	)	$	—	$	—		$	59	$	35
Other	9			—			—				—			—			—			—			—		—			9		—
Total derivative instruments	19			36			—				—			18			—			(5		)	—		—			68		35
Total liabilities carried at fair value	$	19		$	36		$	—			$	—		$	18		$	—		$	(5	)	$	—	$	—		$	68	$	35
	Fair-Value Measurements Using Significant Unobservable Inputs
	Nine Months Ended September 30, 2014
	Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	December 31,			Unrealized Gains (Losses)																			into		out of			September 30,		Unrealized
	2013																						Level 3		Level 3			2014		Gains
																														(Losses)
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2014
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies, mortgage-backed securities	$	716		$	—		$	—			$	168		$	—		$	—		$	(14	)	$	—	$	(610	)	$	260
Asset-backed securities:
Student loans	423			1			2				24			—			(74		)	(31		)	—		(79		)	266
Credit cards	24			—			—				—			—			—			(24		)	—		—			—
Other	4,532			46			(14		)		282			—			—			(902		)	—		—			3,944
Total asset-backed securities	4,979			47			(12		)		306			—			(74		)	(957		)	—		(79		)	4,210
Non-U.S. debt securities:
Mortgage-backed securities	375			—			—				—			—			—			—			—		(375		)	—
Asset-backed securities	798			5			—				—			—			—			(219		)	76		(236		)	424
Other	464			—			—				55			—			(1		)	(28		)	—		(192		)	298
Total non-U.S. debt securities	1,637			5			—				55			—			(1		)	(247		)	76		(803		)	722
State and political subdivisions	43			1			(1		)		—			—			—			(2		)	—		—			41
Collateralized mortgage obligations	162			—			1				205			—			(6		)	(20		)	—		(108		)	234
Other U.S. debt securities	8			—			—				—			—			—			—			—		—			8
Total investment securities available for sale	7,545			53			(12		)		734			—			(81		)	(1,240		)	76		(1,600		)	5,475
Other assets:
Derivative instruments:
Derivative instruments, Foreign exchange contracts	19			26			—				32			—			—			(9		)	—		—			68		$	35
Total derivative instruments	19			26			—				32			—			—			(9		)	—		—			68		35
Total assets carried at fair value	$	7,564		$	79		$	(12	)		$	766		$	—		$	(81	)	$	(1,249	)	$	76	$	(1,600	)	$	5,543	$	35
	Fair-Value Measurements Using Significant Unobservable Inputs
	Nine months ended September 30, 2014
	Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	December 31,			Unrealized (Gains) Losses																			into		out of			September 30,		Unrealized
	2013																						Level 3		Level 3			2014		(Gains)
																														Losses
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2014
				in			in Other
				Revenue			Comprehensive
							Income
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	17		$	22		$	—			$	—		$	28		$	—		$	(8	)	$	—	$	—		$	59	$	32
Other	9			—			—				—			—			—			—			—		—			9		—
Total derivative instruments	26			22			—				—			28			—			(8		)	—		—			68		32
Total liabilities carried at fair value	$	26		$	22		$	—			$	—		$	28		$	—		$	(8	)	$	—	$	—		$	68	$	32
	Fair Value Measurements Using Significant Unobservable Inputs
	Three Months Ended September 30, 2013
	Fair Value as of June 30,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	2013			Unrealized Gains (Losses)																			into		out of			30-Sep-13		Unrealized
																							Level 3		Level 3					Gains
																														(Losses)
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies, mortgage-backed securities	$	864		$	—		$	(1	)		$	—		$	—		$	—		$	(29	)	$	—	$	(93	)	$	741
Asset-backed securities:
Student loans	380			—			(2		)		—			—			—			(10		)	—		—			368
Credit cards	24			—			—				—			—			—			—			—		—			24
Other	3,848			13			(5		)		793			—			(24		)	(275		)	—		—			4,350
Total asset-backed securities	4,252			13			(7		)		793			—			(24		)	(285		)	—		—			4,742
Non-U.S. debt securities:
Mortgage-backed securities	328			—			(1		)		—			—			—			13			—		—			340
Asset-backed securities	756			1			1				164			—			—			(19		)	—		(104		)	799
Other	281			—			(1		)		149			—			—			12			—		—			441
Total non-U.S. debt securities	1,365			1			(1		)		313			—			—			6			—		(104		)	1,580
State and political subdivisions	45			—			(1		)		—			—			—			—			—		—			44
Collateralized mortgage obligations	238			—			(5		)		50			—			—			(11		)	15		(100		)	187
Other U.S. debt securities	9			—			—				—			—			—			—			—		—			9
Total investment securities available for sale	6,773			14			(15		)		1,156			—			(24		)	(319		)	15		(297		)	7,303
Other assets:
Derivative instruments:
Derivative instruments, Foreign exchange contracts	121			(21		)	—				7			—			—			(30		)	—		—			77		$	(16	)
Total derivative instruments	121			(21		)	—				7			—			—			(30		)	—		—			77		(16		)
Total assets carried at fair value	$	6,894		$	(7	)	$	(15	)		$	1,163		$	—		$	(24	)	$	(349	)	$	15	$	(297	)	$	7,380	$	(16	)
	Fair Value Measurements Using Significant Unobservable Inputs
	Three Months Ended September 30, 2013
	Fair Value as of June 30,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair		Change in
	2013			Unrealized (Gains) Losses																			into		out of			Value as of		Unrealized
																							Level 3		Level 3			September 30,		(Gains)
																												2013		Losses
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	108		$	(17	)	$	—			$	—		$	5		$	—		$	(41	)	$	—	$	—		$	55	$	(15	)
Other	9			—			—				—			—			—			—			—		—			9		—
Total derivative instruments	117			(17		)	—				—			5			—			(41		)	—		—			64		(15		)
Total liabilities carried at fair value	$	117		$	(17	)	$	—			$	—		$	5		$	—		$	(41	)	$	—	$	—		$	64	$	(15	)
	Fair-Value Measurements Using Significant Unobservable Inputs
	Nine Months Ended September 30, 2013
	Fair Value  as of December 31,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	2012			Unrealized Gains (Losses)																			into		out of			September 30,		Unrealized
																							Level 3		Level 3			2013		Gains
																														(Losses)
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies:
Mortgage-backed securities	$	825		$	—		$	(1	)		$	92		$	—		$	—		$	(83	)	$	—	$	(92	)	$	741
Asset-backed securities:
Student loans	588			1			6				—			—			(26		)	(26		)	—		(175		)	368
Credit cards	67			—			—				—			—			—			(43		)	—		—			24
Other	3,994			40			25				1,358			—			(33		)	(1,034		)	—		—			4,350
Total asset-backed securities	4,649			41			31				1,358			—			(59		)	(1,103		)	—		(175		)	4,742
Non-U.S. debt securities:
Mortgage-backed securities	555			—			(1		)		—			—			—			(6		)	—		(208		)	340
Asset-backed securities	524			4			2				399			—			—			(88		)	139		(181		)	799
Other	140			—			—				328			—			—			13			—		(40		)	441
Total non-U.S. debt securities	1,219			4			1				727			—			—			(81		)	139		(429		)	1,580
State and political subdivisions	48			—			(1		)		—			—			—			(3		)	—		—			44
Collateralized mortgage obligations	117			1			(5		)		190			—			—			(31		)	15		(100		)	187
Other U.S. debt securities	9			—			—				—			—			—			—			—		—			9
Total investment securities available for sale	6,867			46			25				2,367			—			(59		)	(1,301		)	154		(796		)	7,303
Other assets:
Derivative instruments:
Foreign exchange contracts	113			119			—				25			—			—			(180		)	—		—			77		$	29
Total derivative instruments	113			119			—				25			—			—			(180		)	—		—			77		29
Total assets carried at fair value	$	6,980		$	165		$	25			$	2,392		$	—		$	(59	)	$	(1,481	)	$	154	$	(796	)	$	7,380	$	29
	Fair-Value Measurements Using Significant Unobservable Inputs
	Nine Months Ended September 30, 2013
	Fair Value  as of December 31,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	2012			Unrealized (Gains) Losses																			into		out of			September 30,		Unrealized
																							Level 3		Level 3			2013		(Gains)
																														Losses
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	106		$	59		$	—			$	—		$	24		$	—		$	(134	)	$	—	$	—		$	55	$	15
Other	9			—			—				—			—			—			—			—		—			9		—
Total derivative instruments	115			59			—				—			24			—			(134		)	—		—			64		15
Total liabilities carried at fair value	$	115		$	59		$	—			$	—		$	24		$	—		$	(134	)	$	—	$	—		$	64	$	15
The following table presents total realized and unrealized gains and losses for the periods indicated that were recorded in revenue for our level-3 financial assets and liabilities:
	Three Months Ended September 30,													Nine Months Ended September 30,
	Total Realized and						Change in							Total Realized and						Change in
	Unrealized Gains						Unrealized Gains							Unrealized Gains						Unrealized Gains
	(Losses) Recorded						(Losses) Related to							(Losses) Recorded						(Losses) Related to
	in Revenue						Financial							in Revenue						Financial
							Instruments Held at													Instruments Held at
							September 30,													September 30,
(In millions)	2014			2013			2014				2013			2014			2013			2014			2013
Fee revenue:
Trading services	$	8		$	(4	)	$	5			$	(1	)	$	4		$	60		$	3		$	14
Total fee revenue	8			(4		)	5				(1		)	4			60			3			14
Net interest revenue	20			14			—				—			53			46			—			—
Total revenue	$	28		$	10		$	5			$	(1	)	$	57		$	106		$	3		$	14
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 September 30, 2014			As of December 31, 2013			Valuation Technique		Significant		As of September 30, 2014		As of December 31, 2013
										Unobservable Input
Significant unobservable inputs readily available to State Street:
Assets:
Asset-backed securities, student loans		$	—		$	13		Discounted cash flows		Credit spread		—	%	3.5	%
Asset-backed securities, credit cards		—			24			Discounted cash flows		Credit spread		—		2
Asset-backed securities, other		66			92			Discounted cash flows		Credit spread		0.2		1.5
State and political subdivisions		41			43			Discounted cash flows		Credit spread		1.6		1.7
Derivative instruments, foreign exchange contracts		68			19			Option model		Volatility		7.7		11.4
Total		$	175		$	191
Liabilities:
Derivative instruments, foreign exchange contracts		$	59		$	17		Option model		Volatility		7.7		11.2
Derivative instruments, other(1)		9			9			Discounted cash flows		Participant redemptions		6		7.5
Total		$	68		$	26
(1) Relates to stable value wrap contracts; refer to the sensitivity discussion following the tables presented below, and to note 7.
The following tables present information with respect to the composition of our level-3 financial assets and
liabilities, by availability of significant unobservable inputs, as of the dates indicated:
30-Sep-14		Significant Unobservable Inputs Readily Available to State Street(1)			Significant Unobservable Inputs Not Developed by State Street and Not Readily Available(2)			Total Assets and Liabilities with Significant Unobservable Inputs
(In millions)
Assets:
U.S. Treasury and federal agencies, mortgage-backed securities		$	—		$	260		$	260
Asset-backed securities, student loans		—			266			266
Asset-backed securities, other		66			3,878			3,944
Non-U.S. debt securities, asset-backed securities		—			424			424
Non-U.S. debt securities, other		—			298			298
State and political subdivisions		41			—			41
Collateralized mortgage obligations		—			234			234
Other U.S. debt securities		—			8			8
Derivative instruments, foreign exchange contracts		68			—			68
Total		$	175		$	5,368		$	5,543
Liabilities:
Derivative instruments, foreign exchange contracts		$	59		$	—		$	59
Derivative instruments, other		9			—			9
Total		$	68		$	—		$	68
(1) Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.
(2) Fair value for these financial assets is measured using non-binding broker or dealer quotes.
31-Dec-13		Significant Unobservable Inputs Readily Available to State Street(1)			Significant Unobservable Inputs Not Developed by State Street and Not Readily Available(2)			Total Assets and Liabilities with Significant Unobservable Inputs
(In millions)
Assets:
U.S. Treasury and federal agencies, mortgage-backed securities		$	—		$	716		$	716
Asset-backed securities, student loans		13			410			423
Asset-backed securities, credit cards		24			—			24
Asset-backed securities, other		92			4,440			4,532
Non-U.S. debt securities, mortgage-backed securities		—			375			375
Non-U.S. debt securities, asset-backed securities		—			798			798
Non-U.S. debt securities, other		—			464			464
State and political subdivisions		43			—			43
Collateralized mortgage obligations		—			162			162
Other U.S. debt securities		—			8			8
Derivative instruments, foreign exchange contracts		19			—			19
Total		$	191		$	7,373		$	7,564
Liabilities:
Derivative instruments, foreign exchange contracts		$	17		$	—		$	17
Derivative instruments, other		9			—			9
Total		$	26		$	—		$	26
(1) Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.
(2) Fair value for these financial assets is measured using non-binding broker or dealer quotes.
We use internally-developed pricing models to measure the fair value of our level-3 financial assets and liabilities, which models incorporate discounted cash flow and option modeling techniques. Use of these techniques requires the determination of relevant inputs and assumptions, some of which represent significant unobservable inputs as indicated in the preceding table. Accordingly, changes in these unobservable inputs may have a significant impact on fair value.
Certain of these unobservable inputs will, in isolation, have a directionally consistent impact on the fair value of the instrument for a given change in that input. Alternatively, the fair value of the instrument may move in an opposite direction for a given change in another input. Where multiple inputs are used within the valuation technique of an asset or liability, a change in one input in a certain direction may be offset by an opposite change in another input, resulting in a potentially muted impact on the overall fair value of that particular instrument. Additionally, a change in one unobservable input may result in a change to another unobservable input (that is, changes in certain inputs are interrelated to one another), which may counteract or magnify the fair-value impact.
For recurring level-3 fair-value measurements for which significant unobservable inputs were readily available to State Street as of September 30, 2014, the sensitivity of the fair-value measurement to
changes in significant unobservable inputs, and a description of any interrelationships between those unobservable inputs, is described below; however, we rarely experience a situation in which those unobservable inputs change in isolation:
•	The significant unobservable input used in the measurement of the fair value of our asset-backed securities and municipal securities (state and political subdivisions) is the credit spread. Significant increases (decreases) in the credit spread would result in measurements of significantly lower (higher) fair value of these securities.
•	The significant unobservable input used in the measurement of the fair value of our foreign exchange option contracts is the implied volatility surface. A significant increase (decrease) in the implied volatility surface would result in measurements of significantly higher (lower) fair value of these contracts.
•	The significant unobservable input used in the measurement of the fair value of our other derivative instruments, specifically stable value wrap contracts, is participant redemptions. Increased volatility of participant redemptions may result in changes to our measurement of fair value. Generally, significant increases (decreases) in participant redemptions may result in measurements of significantly higher (lower) fair value of this liability.
Fair Values of Financial Instruments:
Estimates of fair value for financial instruments not carried at fair value on a recurring basis in our consolidated statement of condition, as defined by GAAP, 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 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; federal funds purchased; and other short-term borrowings.
In addition, due to the relatively short duration of certain of our net loans (excluding leases), 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 and purchased receivables, 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 instruments defined by GAAP, excluding financial assets and liabilities 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
30-Sep-14		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)
(In millions)
Financial Assets:
Cash and due from banks		$	4,146		$	4,146		$	4,146			$	—		$	—
Interest-bearing deposits with banks		86,946			86,946			—				86,946			—
Securities purchased under resale agreements		2,603			2,603			—				2,603			—
Investment securities held to maturity		18,767			18,865			—				18,865			—
Net loans (excluding leases)		17,296			17,287			—				16,830			457
Financial Liabilities:
Deposits:
Noninterest-bearing		$	66,134		$	66,134		$	—			$	66,134		$	—
Interest-bearing - U.S.		24,435			24,435			—				24,435			—
Interest-bearing - non-U.S.		117,399			117,399			—				117,399			—
Securities sold under repurchase agreements		9,385			9,385			—				9,385			—
Federal funds purchased		17			17			—				17			—
Other short-term borrowings		4,307			4,307			—				4,307			—
Long-term debt		9,016			9,352			—				8,474			878
								Fair-Value Hierarchy
31-Dec-13		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)
(In millions)
Financial Assets:
Cash and due from banks		$	3,220		$	3,220		$	3,220			$	—		$	—
Interest-bearing deposits with banks		64,257			64,257			—				64,257			—
Securities purchased under resale agreements		6,230			6,230			—				6,230			—
Investment securities held to maturity		17,740			17,560			—				17,560			—
Net loans (excluding leases)		12,363			12,355			—				11,908			447
Financial Liabilities:
Deposits:
Noninterest-bearing		$	65,614		$	65,614		$	—			$	65,614		$	—
Interest-bearing - U.S.		13,392			13,392			—				13,392			—
Interest-bearing - non-U.S.		103,262			103,262			—				103,262			—
Securities sold under repurchase agreements		7,953			7,953			—				7,953			—
Federal funds purchased		19			19			—				19			—
Other short-term borrowings		3,780			3,780			—				3,780			—
Long-term debt		9,699			9,909			—				9,056			853

Investment_Securities

Investment Securities	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Investment Securities	'
	Investment Securities
	The following table presents the amortized cost and fair value, and associated unrealized gains and losses, of investment securities as of the dates indicated:
		September 30, 2014										December 31, 2013
		Amortized			Gross					Fair		Amortized		Gross				Fair
		Cost			Unrealized					Value		Cost		Unrealized				Value
	(In millions)				Gains			Losses						Gains		Losses
	Available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	$	10,751		$	17		$	4	$	10,764	$	702	$	9	$	2	$	709
	Mortgage-backed securities	21,203			196			198		21,201		23,744		211		392		23,563
	Asset-backed securities:
	Student loans(1)	12,806			122			122		12,806		14,718		92		268		14,542
	Credit cards	3,128			13			30		3,111		8,230		21		41		8,210
	Sub-prime	1,054			2			59		997		1,291		3		91		1,203
	Other	4,239			114			10		4,343		4,949		138		23		5,064
	Total asset-backed securities	21,227			251			221		21,257		29,188		254		423		29,019
	Non-U.S. debt securities:
	Mortgage-backed securities	10,056			185			2		10,239		10,808		230		9		11,029
	Asset-backed securities	3,433			15			1		3,447		5,369		23		2		5,390
	Government securities	3,605			8			—		3,613		3,759		2		—		3,761
	Other	5,802			55			8		5,849		4,679		59		11		4,727
	Total non-U.S. debt securities	22,896			263			11		23,148		24,615		314		22		24,907
	State and political subdivisions	10,366			323			44		10,645		10,301		160		198		10,263
	Collateralized mortgage obligations	4,629			57			15		4,671		5,275		70		76		5,269
	Other U.S. debt securities	4,189			106			11		4,284		4,876		138		34		4,980
	U.S. equity securities	29			9			—		38		28		6		—		34
	Non-U.S. equity securities	2			—			—		2		1		—		—		1
	U.S. money-market mutual funds	532			—			—		532		422		—		—		422
	Non-U.S. money-market mutual funds	10			—			—		10		7		—		—		7
	Total	$	95,834		$	1,222		$	504	$	96,552	$	99,159	$	1,162	$	1,147	$	99,174
	Held to maturity:
	U.S. Treasury and federal agencies:
	Direct obligations	$	5,117		$	—		$	222	$	4,895	$	5,041	$	—	$	448	$	4,593
	Mortgage-backed securities	68			4			—		72		91		6		—		97
	Asset-backed securities:
	Student loans(1)	1,873			5			1		1,877		1,627		—		10		1,617
	Credit cards	897			2			—		899		762		1		—		763
	Other	633			3			1		635		782		1		2		781
	Total asset-backed securities	3,403			10			2		3,411		3,171		2		12		3,161
	Non-U.S. debt securities:
	Mortgage-backed securities	4,153			192			16		4,329		4,211		150		48		4,313
	Asset-backed securities	3,293			18			—		3,311		2,202		19		—		2,221
	Government securities	110			—			—		110		2		—		—		2
	Other	75			—			—		75		192		—		—		192
	Total non-U.S. debt securities	7,631			210			16		7,825		6,607		169		48		6,728
	State and political subdivisions	12			—			—		12		24		1		—		25
	Collateralized mortgage obligations	2,536			129			15		2,650		2,806		176		26		2,956
	Total	$	18,767		$	353		$	255	$	18,865	$	17,740	$	354	$	534	$	17,560
	(1) Substantially composed of securities guaranteed by the federal government with respect to at least 97% of defaulted principal and
	accrued interest on the underlying loans.
	Aggregate investment securities with carrying values of $44.77 billion and $46.99 billion as of September 30, 2014 and December 31, 2013, respectively, were designated as pledged for public and trust deposits, short-term borrowings and for other purposes as provided by law.
	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
	September 30, 2014	Fair			Gross			Fair		Gross		Fair		Gross
		Value			Unrealized			Value		Unrealized		Value		Unrealized
	(In millions)				Losses					Losses				Losses
	Available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	$	4,374		$	3		$	158	$	1	$	4,532	$	4
	Mortgage-backed securities	3,391			23			7,026		175		10,417		198
	Asset-backed securities:
	Student loans	291			2			6,158		120		6,449		122
	Credit cards	—			—			1,258		30		1,258		30
Sub-prime	—			—			936		59		936		59
Other	606			2			506		8		1,112		10
Total asset-backed securities	897			4			8,858		217		9,755		221
Non-U.S. debt securities:
Mortgage-backed securities	443			1			176		1		619		2
Asset-backed securities	—			—			84		1		84		1
Other	2,148			2			283		6		2,431		8
Total non-U.S. debt securities	2,591			3			543		8		3,134		11
State and political subdivisions	439			2			1,786		42		2,225		44
Collateralized mortgage obligations	886			5			314		10		1,200		15
Other U.S. debt securities	336			2			294		9		630		11
Total	$	12,914		$	42		$	18,979	$	462	$	31,893	$	504
Held to maturity:
U.S. Treasury and federal agencies:
Direct obligations	$	114		$	1		$	4,781	$	221	$	4,895	$	222
Asset-backed securities:
Student loans	364			1			—		—		364		1
Other	79			1			—		—		79		1
Total asset-backed securities	443			2			—		—		443		2
Non-U.S. mortgage-backed securities
Mortgage-backed securities	255			1			658		15		913		16
Total non-U.S. debt securities	255			1			658		15		913		16
Collateralized mortgage obligations	467			3			552		12		1,019		15
Total	$	1,279		$	7		$	5,991	$	248	$	7,270	$	255
	Less than 12 months						12 months or longer				Total
December 31, 2013	Fair			Gross			Fair		Gross		Fair		Gross
	Value			Unrealized			Value		Unrealized		Value		Unrealized
(In millions)				Losses					Losses				Losses
Available for sale:
U.S. Treasury and federal agencies:
Direct obligations	$	182		$	1		$	113	$	1	$	295	$	2
Mortgage-backed securities	10,562			316			2,389		76		12,951		392
Asset-backed securities:
Student loans	1,930			16			7,252		252		9,182		268
Credit cards	3,714			30			161		11		3,875		41
Sub-prime	—			—			1,150		91		1,150		91
Other	1,896			12			439		11		2,335		23
Total asset-backed securities	7,540			58			9,002		365		16,542		423
Non-U.S. debt securities:
Mortgage-backed securities	868			2			258		7		1,126		9
Asset-backed securities	551			1			16		1		567		2
Other	1,655			9			150		2		1,805		11
Total non-U.S. debt securities	3,074			12			424		10		3,498		22
State and political subdivisions	3,242			113			1,268		85		4,510		198
Collateralized mortgage obligations	1,581			55			510		21		2,091		76
Other U.S. debt securities	1,039			25			58		9		1,097		34
Total	$	27,220		$	580		$	13,764	$	567	$	40,984	$	1,147
Held to maturity:
U.S. Treasury and federal agencies:
Direct obligations	$	4,571		$	448		$	—	$	—	$	4,571	$	448
Asset-backed securities:
Student Loans	1,352			10			—		—		1,352		10
Other	297			1			29		1		326		2
Total asset-backed securities	1,649			11			29		1		1,678		12
Non-U.S. mortgage-backed securities	834			3			878		45		1,712		48
Collateralized mortgage obligations	759			18			161		8		920		26
Total	$	7,813		$	480		$	1,068	$	54	$	8,881	$	534
The following table presents contractual maturities of debt investment securities as of September 30, 2014:
(In millions)	Under 1			1 to 5			6 to 10		Over 10
	Year			Years			Years		Years
Available for sale:
U.S. Treasury and federal agencies:
Direct obligations	$	151		$	6,766		$	3,300	$	547
Mortgage-backed securities	183			2,441			4,753		13,824
Asset-backed securities:
Student loans	342			6,572			3,750		2,142
Credit cards	307			1,513			1,291		—
Sub-prime	9			14			—		974
Other	255			1,069			1,149		1,870
Total asset-backed securities	913			9,168			6,190		4,986
Non-U.S. debt securities:
Mortgage-backed securities	2,190			4,344			384		3,321
Asset-backed securities	359			2,691			290		107
Government securities	1,978			1,635			—		—
Other	1,969			2,942			938		—
Total non-U.S. debt securities	6,496			11,612			1,612		3,428
State and political subdivisions	731			3,021			4,451		2,442
Collateralized mortgage obligations	286			1,165			1,072		2,148
Other U.S. debt securities	700			3,221			328		35
Total	$	9,460		$	37,394		$	21,706	$	27,410
Held to maturity:
U.S. Treasury and federal agencies:
Direct obligations	$	—		$	—		$	5,000	$	117
Mortgage-backed securities	—			15			13		40
Asset-backed securities
Student loans	7			182			393		1,291
Credit cards	—			375			522		—
Other	19			401			208		5
Total asset-backed securities	26			958			1,123		1,296
Non-U.S. debt securities:
Mortgage-backed securities	323			1,208			274		2,348
Asset-backed securities	5			3,051			237		—
Government securities	110			—			—		—
Other	—			75			—		—
Total non-U.S. debt securities	438			4,334			511		2,348
State and political subdivisions	9			3			—		—
Collateralized mortgage obligations	577			550			503		906
Total	$	1,050		$	5,860		$	7,150	$	4,707
The maturities of asset-backed securities, mortgage-backed securities and collateralized mortgage obligations are based on expected principal payments.
The following tables present gross realized gains and gross realized losses from sales of available-for-sale securities, and the components of net impairment losses included in net gains and losses related to investment securities, for the periods indicated:
	Three Months Ended September 30,
(In millions)	2014			2013
Gross realized gains from sales of available-for-sale securities	$	48		$	11
Gross realized losses from sales of available-for-sale securities	(48		)	(5		)
Net impairment losses:
Gross losses from other-than-temporary impairment	—			(13		)
Losses reclassified (from) to other comprehensive income	—			3
Net impairment losses(1)	—			(10		)
Gains related to investment securities, net	$	—		$	(4	)
(1) Net impairment losses, recognized in our consolidated statement of income, were composed of the following:
Impairment associated with expected credit losses	$	—		$	(8	)
Impairment associated with management's intent to sell impaired securities prior to recovery in value	—			—
Impairment associated with adverse changes in timing of expected future cash flows	—			(2		)
Net impairment losses	$	—		$	(10	)
	Nine Months Ended September 30,
(In millions)	2014			2013
Gross realized gains from sales of available-for-sale securities	$	64		$	98
Gross realized losses from sales of available-for-sale securities	(49		)	(87		)
Net impairment losses:
Gross losses from other-than-temporary impairment	(1		)	(19		)
Losses reclassified (from) to other comprehensive income	(10		)	(1		)
Net impairment losses(1)	(11		)	(20		)
Gains related to investment securities, net	$	4		$	(9	)
(1) Net impairment losses, recognized in our consolidated statement of income, were composed of the following:
Impairment associated with expected credit losses	$	(10	)	$	(8	)
Impairment associated with management's intent to sell impaired securities prior to recovery in value	—			(6		)
Impairment associated with adverse changes in timing of expected future cash flows	(1		)	(6		)
Net impairment losses	$	(11	)	$	(20	)
The following table presents activity with respect to net impairment losses for the periods indicated:
	Nine Months Ended September 30,
(In millions)	2014			2013
Beginning balance	$	122		$	124
Plus losses for which other-than-temporary impairment was not previously recognized	—			14
Plus losses for which other-than-temporary impairment was previously recognized	11			6
Less previously recognized losses related to securities sold or matured	(11		)	(10		)
Less losses related to securities intended or required to be sold	(6		)	—
Ending balance	$	116		$	134
Impairment:
We conduct periodic reviews of individual securities to assess whether other-than-temporary impairment exists. Impairment exists when the current fair value of an individual security is below its amortized cost basis. When the decline in the security's fair value is deemed to be other than temporary, the loss is recorded in our consolidated statement of income. In addition, for debt securities available for sale and held to maturity, 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 other-than-temporary impairment, 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 mortgage- and asset-backed securities;
•	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;
•	discussion and evaluation of factors or triggers that could cause individual securities to be deemed other-than- temporarily impaired and those that would not support other-than-temporary impairment; 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 other-than-temporary impairment 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 to its amortized cost basis.
The following provides a description of our process for the identification and assessment of other-than-temporary impairment, as well as information about other-than-temporary impairment recorded in the three and nine months ended September 30, 2014 and 2013 and changes in period-end unrealized losses, for major security types.
U.S. Agency Securities
Our portfolio of U.S. agency direct obligations and mortgage-backed securities 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 other-than-temporary impairment on these securities in the three and nine months ended September 30, 2014 or 2013. The overall decline in the unrealized losses on these securities as of September 30, 2014 compared to December 31, 2013 was primarily attributable to narrowing spreads in the nine months ended September 30, 2014.
Asset-Backed Securities - Student Loans
Asset-backed securities collateralized by student loans are primarily composed of securities collateralized by Federal Family Education Loan Program, or 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 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 other-than-temporary impairment on these securities in the three and nine months ended September 30, 2014 or 2013. The gross unrealized losses in our FFELP loan-backed securities portfolio as of September 30, 2014 were primarily attributable to the lower spreads on these securities relative to those associated with more current issuances. The decline in the unrealized losses on these securities as of September 30, 2014 compared to December 31, 2013 was primarily attributable to narrowing spreads in the nine months ended September 30, 2014.
Our assessment of other-than-temporary impairment 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 September 30, 2014.
Our total exposure to private student loan-backed securities was less than $800 million as of September 30, 2014. Our assessment of other-than-temporary impairment 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 other-than-temporary impairment on these securities in the three and nine months ended September 30, 2014 or 2013.
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 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 other-than-temporary impairment exists.
In the nine months ended September 30, 2014, we recorded other-than-temporary impairment of $1 million on non-U.S. residential mortgage-backed securities in our consolidated statement of income, associated with adverse changes in the timing of expected future cash flows from the securities. In the three and nine months ended September 30, 2013, we recorded other-than-temporary impairment of $2 million and $6 million, respectively, on these securities in our consolidated statement of income, associated with adverse changes in the timing of expected future cash flows from the securities.
In addition, in the nine months ended September 30, 2013, we recorded other-than-temporary impairment of $6 million on these securities in our consolidated statement of income, all in the three months ended June 30, 2013, associated with management's intent to sell the impaired security prior to its recovery in value.
Our aggregate exposure to Spain, Italy, Ireland and Portugal with respect to mortgage- and asset-backed securities totaled approximately $910 million as of September 30, 2014, composed of $173 million in Spain, $555 million in Italy, $109 million in Ireland and $73 million in Portugal. We had no direct sovereign debt exposure to any of these countries as of that date. As of September 30, 2014, these mortgage- and asset-backed securities had an aggregate pre-tax net unrealized gain of approximately $125 million, composed of gross unrealized gains of $126 million and gross unrealized losses of $1 million. We recorded the above-mentioned other-than-temporary impairment of $6 million on one of these securities, all in the three months ended June 30, 2013.
Our assessment of other-than-temporary impairment of these securities takes into account government intervention in the corresponding mortgage markets and assumes a conservative baseline macroeconomic environment for this region, factoring in slower economic growth and continued government austerity measures. Our baseline view assumes a recessionary period characterized by high unemployment and by additional housing price declines of between 9% and 15% across these four countries. Our evaluation of other-than-temporary impairment in our base case does not assume a disorderly sovereign-debt restructuring or a break-up of the Eurozone. In addition, we perform stress testing and sensitivity analysis in order to understand the impact of more severe assumptions on potential other-than-temporary impairment.
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 9. Our portfolio of other U.S. debt securities is primarily composed of securities issued by U.S. corporations.
Our assessment of other-than-temporary impairment 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 other-than-temporary impairment on these securities in the three and nine months ended September 30, 2014 or 2013. The decline in the unrealized losses on these securities as of September 30, 2014 compared to December 31, 2013 was primarily attributable to the narrowing of spreads and U.S. Treasury rates in the nine months ended September 30, 2014.
U.S. Non-Agency Residential Mortgage-Backed Securities
We assess other-than-temporary impairment 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 other-than-temporary impairment on these securities in the three and nine months ended September 30, 2014 or 2013.
U.S. Non-Agency Commercial Mortgage-Backed Securities
With respect to our portfolio of U.S. non-agency commercial mortgage-backed securities, other-than-temporary impairment 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. In the nine months ended September 30, 2014, we recorded other-than-temporary impairment of $10 million on these securities in our consolidated statement of income, all associated with credit losses. We recorded $8 million of other-than-temporary impairment on these securities, all associated with credit losses, in our consolidated statement of income in both the three and nine months ended September 30, 2013.
*****
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 other-than-temporary impairment, since the loss is ultimately subject to a discount commensurate with the purchase yield of the security.
In the aggregate, we recorded no other-than-temporary impairment in three months ended September 30, 2014, and $11 million in the nine months ended September 30, 2014, compared to $10 million and $20 million in the three and nine months ended September 30, 2013, respectively, as summarized below:
Nine months ended September 30, 2014:
•	$1 million (non-U.S. mortgage-backed securities) resulted from adverse changes in the timing of expected future cash flows from the securities; and
•	$10 million (U.S. non-agency commercial mortgage-backed securities) was associated with expected credit losses.
Three and nine months ended September 30, 2013:
•	$8 million in both periods was associated with expected credit losses;
•	$2 million and $6 million (non-U.S. mortgage-backed securities), respectively, resulted from adverse changes in the timing of expected future cash flows from certain of the securities; and
•	$6 million in the nine months ended September 30, 2013 was associated with management's intent to sell the impaired security prior to its recovery in value.
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 mortgage- and asset-backed securities and other relevant factors, and excluding other-than-temporary impairment recorded in the nine months ended September 30, 2014, management considers the aggregate decline in fair value of the investment securities portfolio and the resulting gross pre-tax unrealized losses of $759 million as of September 30, 2014, related to 1,459 securities, to be temporary, and not the result of any material changes in the credit characteristics of the securities.

Loans_and_Leases

Loans and Leases	9 Months Ended
	Sep. 30, 2014
Loans and Leases Receivable Disclosure [Abstract]	'
Loans and Leases	'
	Loans and Leases
	The following table presents our recorded investment in loans and leases, by segment and class, as of the dates indicated:
	(In millions)	September 30, 2014			December 31, 2013
	Institutional:
	Investment funds:
	U.S.	$	10,896		$	8,695
	Non-U.S.	3,250			1,718
	Commercial and financial:
	U.S.	2,506			1,372
	Non-U.S.	240			154
	Purchased receivables:
	U.S.	142			217
	Non-U.S.	—			26
	Lease financing:
	U.S.	340			339
	Non-U.S.	728			756
	Total institutional	18,102			13,277
	Commercial real estate:
	U.S.	296			209
	Total loans and leases	18,398			13,486
	Allowance for loan losses	(34		)	(28		)
	Loans and leases, net of allowance for loan losses	$	18,364		$	13,458
	Aggregate short-duration advances to our clients included in the institutional segment were $5.39 billion and $2.45 billion as of September 30, 2014 and December 31, 2013, respectively.
	The commercial and financial class in the institutional segment presented in the table above included approximately $1.72 billion and $724 million of senior secured bank loans as of September 30, 2014 and December 31, 2013, respectively. These senior secured bank loans are included in the “speculative” category in the credit-quality-indicator tables presented below. As of September 30, 2014, our allowance for loan losses included approximately $22 million related to these loans.
	The commercial real estate, or CRE, segment is composed of the loans acquired in 2008 pursuant to indemnified repurchase agreements with an affiliate of Lehman as a result of the Lehman Brothers bankruptcy. These loans, which are primarily collateralized by direct and indirect interests in commercial real estate, were recorded at their then-current fair value, based on management’s expectations with respect to future cash flows from the loans using appropriate market discount rates as of the date of acquisition. These cash flow estimates are updated quarterly to reflect changes in management’s expectations, which consider market conditions and other factors.
	The following tables present our recorded investment in each class of loans and leases by credit quality indicator as of the dates indicated:
		Institutional										Commercial Real Estate
	September 30, 2014	Investment			Commercial and Financial			Purchased		Lease		Property Development		Other		Total
		Funds						Receivables		Financing						Loans and
	(In millions)															Leases
	Investment grade(1)	$	13,864		$	916		$	142	$	1,034	$	—	$	28	$	15,984
	Speculative(2)	282			1,830			—		34		268		—		2,414
	Total	$	14,146		$	2,746		$	142	$	1,068	$	268	$	28	$	18,398
		Institutional										Commercial Real Estate
	December 31, 2013	Investment			Commercial and Financial			Purchased		Lease		Property Development		Other		Total
		Funds						Receivables		Financing						Loans and
	(In millions)															Leases
	Investment grade(1)	$	10,282		$	740		$	243	$	1,068	$	—	$	29	$	12,362
	Speculative(2)	131			770			—		27		180		—		1,108
	Special mention(3)	—			16			—		—		—		—		16
	Total	$	10,413		$	1,526		$	243	$	1,095	$	180	$	29	$	13,486
	(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.
	Loans and leases are categorized in the rating categories presented in the preceding table that align with our internal risk-rating framework. Management considers the ratings to be current as of September 30, 2014. 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 sources 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.
	The following table presents our recorded investment in loans and leases, disaggregated based on our impairment methodology, as of the dates indicated:
		September 30, 2014								December 31, 2013
	(In millions)	Institutional			Commercial Real Estate			Total Loans and Leases		Institutional		Commercial Real Estate		Total Loans and Leases
	Loans and leases:
	Individually evaluated for impairment	$	—		$	130		$	130	$	26	$	180	$	206
	Collectively evaluated for impairment(1)	18,102			166			18,268		13,251		29		13,280
	Total	$	18,102		$	296		$	18,398	$	13,277	$	209	$	13,486
	(1) As of September 30, 2014 and December 31, 2013, all of the allowance for loan losses of $34 million and $28 million, respectively, related to institutional loans collectively evaluated for impairment.
	The following tables present information related to our recorded investment in impaired loans and leases as of the dates, or for the periods, indicated:
		September 30, 2014								December 31, 2013
	(In millions)	Recorded Investment			Unpaid			Related Allowance(1)		Recorded Investment		Unpaid		Related Allowance(1)
					Principal							Principal
					Balance							Balance
	With no related allowance recorded:
	CRE—property development	$	130		$	143		$	—	$	130	$	143	$	—
	CRE—property development—acquired credit-impaired	—			34			—		—		34		—
	CRE—other—acquired credit-impaired	—			22			—		—		21		—
Total CRE	$	130		$	199		$	—	$	130	$	198	$	—
(1) As of September 30, 2014 and December 31, 2013, all of the allowance for loan losses of $34 million and $28 million, respectively, related to loans that were not impaired.
	Three Months Ended September 30,
	Average Recorded Investment						Interest Revenue Recognized
	2014			2013			2014		2013
(In millions)
With no related allowance recorded:
CRE—property development	$	130		$	130		$	3	$	2
Total CRE	$	130		$	130		$	3	$	2
	Nine Months Ended September 30,
	Average Recorded Investment						Interest Revenue Recognized
	2014			2013			2014		2013
(In millions)
With no related allowance recorded:
CRE—property development	$	130		$	160		$	8	$	17
Total CRE	$	130		$	160		$	8	$	17
As of both September 30, 2014 and December 31, 2013, we held an aggregate of approximately $130 million of CRE loans, presented in the preceding impaired loans and leases table, which were modified in troubled debt restructurings.
No impairment loss was recognized as a result of restructuring the loans, as the discounted cash flows of the modified loans exceeded the carrying amount of the original loans as of the modification date. In the nine months ended September 30, 2014 and the year ended December 31, 2013, no loans were modified in troubled debt restructurings.
The following tables present activity in the allowance for loan losses for the periods indicated:
	Three Months Ended September 30,
	2014								2013
(In millions)	Institutional			Commercial			Total Loans and Leases		Institutional		Commercial		Total Loans and Leases
				Real Estate							Real Estate
Allowance for loan losses(1):
Beginning balance	$	32		$	—		$	32	$	22	$	—	$	22
Charge-offs	—			—			—		—		—		—
Provisions	2			—			2		—		—		—
Recoveries	—			—			—		—		—		—
Ending balance	$	34		$	—		$	34	$	22	$	—	$	22
	Nine Months Ended September 30,
	2014								2013
(In millions)	Institutional			Commercial			Total Loans and Leases		Institutional		Commercial		Total Loans and Leases
				Real Estate							Real Estate
Allowance for loan losses(1):
Beginning balance	$	28		$	—		$	28	$	22	$	—	$	22
Charge-offs	—			—			—		—		—		—
Provisions	6			—			6		—		—		—
Recoveries	—			—			—		—		—		—
Ending balance	$	34		$	—		$	34	$	22	$	—	$	22
(1) As of September 30, 2014, approximately $22 million of our allowance for loan losses was related to senior secured bank loans included in the institutional segment; the remaining $12 million was related to other commercial-and-financial loans in the institutional segment.
The provision of $2 million recorded in the three months ended September 30, 2014 was associated with an increase in our estimate of credit losses incurred on our portfolio of senior secured bank loans, as the portfolio continues to grow and become more seasoned. These loans are held in connection with our participation in loan syndications in the non-investment-grade lending market.
The provision of $6 million recorded in the nine months ended September 30, 2014 was composed of a provision of $16 million associated with the senior
secured bank loans, offset by a negative provision of $10 million associated with the pay-down of an unrelated commercial and financial loan with speculative-rated credit quality.
Loans and leases are reviewed on a regular basis, and any provisions for loan losses that are recorded reflect management's estimate of the amount necessary to maintain the allowance for loan losses at a level considered appropriate to absorb estimated incurred losses in the loan-and-lease portfolio.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Other Intangible Assets	'
	Goodwill and Other Intangible Assets
	The following table presents changes in the carrying amount of goodwill during the periods indicated:
		Nine Months Ended September 30,
		2014									2013
	(In millions)	Investment			Investment			Total			Investment			Investment			Total
		Servicing			Management						Servicing			Management
	Goodwill:
	Beginning balance	$	5,999		$	37		$	6,036		$	5,941		$	36		$	5,977
	Foreign currency translation and other, net	(134		)	(3		)	(137		)	28			1			29
	Ending balance	$	5,865		$	34		$	5,899		$	5,969		$	37		$	6,006
	The following table presents changes in the net carrying amount of other intangible assets during the periods indicated:
		Nine Months Ended September 30,
		2014									2013
	(In millions)	Investment			Investment			Total			Investment			Investment			Total
		Servicing			Management						Servicing			Management
	Other intangible assets:
	Beginning balance	$	2,321		$	39		$	2,360		$	2,492		$	47		$	2,539
	Amortization	(155		)	(7		)	(162		)	(153		)	(7		)	(160		)
	Foreign currency translation and other, net	(75		)	(2		)	(77		)	17			—			17
	Ending balance	$	2,091		$	30		$	2,121		$	2,356		$	40		$	2,396
	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:
		September 30, 2014									December 31, 2013
	(In millions)	Gross			Accumulated			Net			Gross			Accumulated			Net
		Carrying			Amortization			Carrying			Carrying			Amortization			Carrying
		Amount						Amount			Amount						Amount
	Client relationships	$	2,614		$	(1,060	)	$	1,554		$	2,706		$	(975	)	$	1,731
	Core deposits	697			(213		)	484			717			(191		)	526
	Other	220			(137		)	83			234			(131		)	103
	Total	$	3,531		$	(1,410	)	$	2,121		$	3,657		$	(1,297	)	$	2,360

Other_Assets

Other Assets	9 Months Ended
	Sep. 30, 2014
Other Assets [Abstract]	'
Other Assets	'
	Other Assets
	The following table presents the components of other assets as of the dates indicated:
	(In millions)	September 30, 2014		December 31, 2013
	Collateral deposits, net	$	17,540	$	13,706
	Unrealized gains on derivative financial instruments, net	8,712		5,476
	Bank-owned life insurance	2,391		2,343
	Investments in joint ventures and other unconsolidated entities	1,741		1,644
	Receivable for securities sold	917		—
	Accounts receivable	843		950
	Receivable for securities settlement	396		195
	Prepaid expenses	307		286
	Income taxes receivable	258		337
	Deferred tax assets, net of valuation allowance	253		263
	Deposits with clearing organizations	231		177
	Other(1)	556		613
	Total	$	34,145	$	25,990
	(1)	Included other real estate owned of approximately $61 million and $59 million as of September 30, 2014 and December 31, 2013, respectively.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2014
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 proceedings on a case-by-case basis. When we have a liability that we deem probable and that we deem can be reasonably estimated as of the date of our consolidated financial statements, we accrue for our estimate of the 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 proceedings and the reasonably estimable loss (or range thereof) are inherently difficult to predict, especially in the early stages of proceedings. Even if a loss is probable, due to many complex factors, such as speed of discovery and the timing of court decisions or rulings, a loss or range of loss might not be reasonably estimated until the later stages of the proceeding.
	As of September 30, 2014, our aggregate accruals for legal loss contingencies and regulatory matters, net of anticipated insurance recoveries, totaled approximately $111 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. We may be subject to proceedings in the future that, if adversely resolved, would have a material adverse effect on our businesses or on our future consolidated financial statements. Except where otherwise noted below, we have not established accruals with respect to the claims discussed and do not believe that potential exposure is probable and can be reasonably estimated.
	The following discussion provides information with respect to significant legal and regulatory matters.
	Securities Finance
	Two related participants in our agency securities lending program have brought suit against us challenging actions taken by us in response to their withdrawal from the program. We believe that certain withdrawals by these participants were inconsistent with the redemption policy applicable to the agency lending collateral pools and, consequently, redeemed their remaining interests through an in-kind distribution that reflected the assets these participants would have received had they acted in accordance with the collateral pools' redemption policy. In taking these actions, we believe that we acted in the best interests of all participants in the collateral pools. The two participants have asserted damages of $125 million, an amount that plaintiffs attribute to alleged deficiencies in the methodology that State Street used to construct the in-kind distribution and alleged errors in the pricing of the securities that plaintiffs received on or about August 2009. While management does not believe that such difference is an appropriate measure of damages, we have been informed that the participants liquidated these securities in June 2013, and we estimate the loss on those sales to be approximately $11 million. As of September 30, 2014, we had $10 million accrued in connection with this matter.
	Foreign Exchange
	We offer our custody clients and their investment managers the option to route foreign exchange transactions to our foreign exchange desk through our asset servicing operation. We record as revenue an amount approximately equal to the difference between the rates we set for those indirect trades and indicative interbank market rates at the time of settlement of the trade.
	As discussed more fully below, claims have been asserted on behalf of certain current and former custody clients, and future claims may be asserted, alleging that our indirect foreign exchange rates (including the differences between those rates and indicative interbank market rates at the time we executed the trades) were not adequately disclosed or were otherwise improper, and seeking to recover, among other things, the full amount of the revenue we obtained from our indirect foreign exchange trading with them.
	In October 2009, the Attorney General of the State of California commenced an action under the California False Claims Act and California Business and Professional Code related to services State Street provides to California state pension plans. The California Attorney General asserts that the pricing of certain foreign exchange trades for these pension plans was governed by the custody contracts for these plans and that our pricing was not consistent with the terms of those contracts and related disclosures to the plans, and that, as a result, State Street made false claims and engaged in unfair competition. The Attorney General asserts actual damages of approximately $100 million for periods from 2001 to 2009 and seeks additional penalties, including treble damages. This action is in the discovery phase.
	We provide custody services to and engage in principal foreign exchange trading with government pension plans in other jurisdictions. Since the commencement of the litigation in California, attorneys general and other government authorities from a number of jurisdictions, as well as U.S. Attorney's offices, the U.S. Department of Labor and the SEC, have requested information or issued subpoenas in connection with inquiries into the pricing of our indirect foreign exchange trading. We continue to respond to such inquiries and subpoenas.
	We engage in indirect foreign exchange trading with a broad range of custody clients in the U.S. and internationally. We have responded and are responding to information requests from a number of clients concerning our indirect foreign exchange rates. In February 2011, a putative class action was filed in federal court in Boston seeking unspecified damages, including treble damages, on behalf of all custodial clients that executed certain foreign exchange transactions with State Street from 1998 to 2009. The putative class action alleges, among other things, that the rates at which State Street executed foreign currency trades constituted an unfair and deceptive practice under Massachusetts law and a breach of the duty of loyalty.
	Two other putative class actions are currently pending in federal court in Boston alleging various violations of ERISA on behalf of all ERISA plans custodied with us that executed indirect foreign exchange trades with State Street from 1998 onward. The complaints allege that State Street caused class members to pay unfair and unreasonable rates on indirect foreign exchange trades with State Street. The complaints seek unspecified damages, disgorgement of profits, and other equitable relief. Other claims may be asserted in the future, including in response to developments in the actions discussed above or governmental proceedings.
	We expect that plaintiffs will seek to recover their share of all or a portion of the revenue that we have recorded from indirect foreign exchange trades. We cannot predict whether a court, in the event of an adverse resolution, would consider our revenue to be the appropriate measure of damages.
	The following table summarizes our estimated total revenue worldwide from indirect foreign exchange trading for the periods indicated:
	(In millions)	Revenue from indirect foreign exchange trading
	2008	$	462
	2009	369
	2010	336
	2011	331
	2012	248
	2013	285
	Nine Months Ended September 30, 2014	186
	We believe that the amount of our revenue from such trading has been of a similar or lesser order of magnitude for many years prior to 2008. Our revenue calculations related to indirect foreign exchange trading reflect a judgment concerning the relationship between the rates we charge for indirect foreign exchange execution and indicative interbank market rates near in time to execution. Our revenue from foreign exchange trading generally depends on the difference between the rates we set for those indirect trades and indicative interbank market rates at the time of settlement of the trade.
	In the third quarter of 2014, we recorded an accrual of $70 million, or $53 million after-tax, reflecting our intention to seek to resolve some, but not all, of the outstanding and potential claims arising out of our indirect foreign exchange client activities. We are engaged in discussions with some, but not all, of the governmental agencies and civil litigants discussed above regarding potential settlements of their outstanding or potential claims. There can be no assurance that we will reach a settlement in any of these matters, that the cost of such settlements would not materially exceed such accrual, or that other claims will not be asserted. We do not currently intend to seek to negotiate settlements with respect to all outstanding and potential claims, and our current efforts, even if successful, will address only a portion of our potential material legal exposure arising out of our indirect foreign exchange client activities.
	Shareholder Litigation
	Three shareholder-related complaints are currently pending in federal court in Boston. One complaint purports to be a class action on behalf of State Street shareholders. The two other complaints purport to be class actions on behalf of participants and beneficiaries in the State Street Salary Savings Program who invested in the program's State Street common stock investment option. The complaints allege various violations of the federal securities laws, common law and ERISA in connection with our public disclosures concerning our investment securities portfolio, our asset-backed commercial paper conduit program, and our foreign exchange trading business. In July 2014, the court preliminarily approved a $60 million class settlement in the shareholder litigation and a $10 million class settlement in the two Salary Savings Program actions. A fourth complaint, a purported shareholder derivative action on behalf of State Street, was dismissed in September 2013. We have entered into an agreement to settle that matter for nominal consideration. As of September 30, 2014, we had an accrual which, together with anticipated insurance recovery, will be sufficient to fund each of these proposed settlements.
	Transition Management
	In January 2014, we entered into a settlement with the U.K. Financial Conduct Authority, or FCA, pursuant to which we paid a fine of £22.9 million (approximately $37.8 million), as a result of our having charged six clients of our U.K. transition management business during 2010 and 2011 amounts in excess of the contractual terms. The SEC and the U.S. Attorney are conducting separate investigations into this matter. As of September 30, 2014, we had remaining accruals of approximately $4.3 million for indemnification costs associated with this matter, including an accrual for one additional client claim arising out of the FCA settlement.
	Investment Servicing
	State Street has been named as a defendant in related complaints by investment management clients of TAG Virgin Islands, Inc., or TAG, who hold or held custodial accounts with State Street. The complaints collectively have alleged various claims in connection with certain assets managed by TAG. As of September 30, 2014, one action remains pending. As of September 30, 2014, we had $4.3 million accrued with respect to these matters.
	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. Unrecognized tax benefits totaled approximately $155 million and $164 million as of September 30, 2014 and December 31, 2013, respectively.
	The Internal Revenue Service, or IRS, is currently reviewing our U.S. income tax returns for the tax years 2010 and 2011. Management believes that we have sufficiently accrued liabilities as of September 30, 2014 for tax exposures, including, but not limited to, exposures related to the review by the IRS of the tax years 2010 and 2011.

Commitments_and_Guarantees

Commitments and Guarantees	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Guarantees	'
	Commitments and Guarantees
	Commitments:
	We had unfunded off-balance sheet commitments to extend credit totaling $24.15 billion and $21.30 billion as of September 30, 2014 and December 31, 2013, respectively. The potential losses associated with these commitments equal the gross contractual amounts, and do not consider the value of any collateral. As of September 30, 2014, approximately 78% 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.
	Guarantees:
	Off-balance sheet guarantees are composed of indemnified securities financing, stable value protection, unfunded commitments to purchase assets, and standby letters of credit. The potential losses associated with these guarantees equal the gross contractual amounts, and do not consider the value of any collateral. The following table presents the aggregate gross contractual amounts of our off-balance sheet guarantees as of the dates indicated. Amounts presented do not reflect participations to independent third parties.
	(In millions)	September 30, 2014		December 31, 2013
	Indemnified securities financing	$	340,239	$	320,078
	Stable value protection	24,305		24,906
	Asset purchase agreements	4,205		4,685
	Standby letters of credit	4,455		4,612
	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 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)	September 30, 2014		December 31, 2013
	Aggregate fair value of indemnified securities financing	$	340,239	$	320,078
	Aggregate fair value of cash and securities held by us, as agent, as collateral for indemnified securities financing	354,516		331,732
	Aggregate fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements	81,870		85,374
	Aggregate fair value of cash and securities held by us or our agents as collateral for investments in indemnified repurchase agreements	87,191		91,097
	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. Collateral provided and received in connection with such transactions is recorded in other assets and accrued expenses and other liabilities, respectively, in our consolidated statement of condition. As of September 30, 2014 and December 31, 2013, we had approximately $15.78 billion and $11.29 billion, respectively, of collateral provided and approximately $7.01 billion and $6.62 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 12. 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.

Variable_Interest_Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2014
Variable Interest Entities [Abstract]	'
Variable Interest Entities	'
	Variable Interest Entities
	Asset-Backed Investment Securities:
	We invest in various forms of asset-backed securities, which we carry in our investment securities portfolio. These asset-backed securities meet the GAAP definition of asset securitization entities, which are considered to be variable interest entities, or VIEs, as defined by GAAP. We are not considered to be the primary beneficiary of these VIEs, as defined by GAAP, since we do not have control over their activities. Additional information about our asset-backed securities 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 investment securities available for sale and other short-term borrowings. We may also provide liquidity and re-marketing services to the trusts. As of September 30, 2014 and December 31, 2013, we carried investment securities available for sale, composed of securities related to state and political subdivisions, with a fair value of $2.30 billion and $2.33 billion, respectively, and other short-term borrowings of $1.89 billion and $1.95 billion, respectively, in our consolidated statement of condition in connection with these trusts.
	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 trusts to third-party investors and to State Street as residual holder. These transfers do not meet the de-recognition criteria defined by GAAP, and therefore, are recorded in our consolidated financial statements. The trusts had a weighted-average life of approximately 6.1 years as of September 30, 2014, compared to approximately 6.5 years as of December 31, 2013.
	Under separate legal agreements, we provide standby bond-purchase agreements to these trusts and, with respect to certain securities, letters of credit. Our commitments to the trusts under these standby bond-purchase agreements and letters of credit totaled $1.92 billion and $684 million, respectively, as of September 30, 2014, none of which was utilized as of that date. In the event that our obligations under these agreements 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.
	Interests in Sponsored Investment Funds:
	In the normal course of business, we manage various types of sponsored investment funds through SSgA. The services we provide to these sponsored investment funds generate management fee revenue. From time to time, we may invest cash in the funds, which we refer to as seed capital, in order for the funds to establish a performance history for newly-launched strategies. These funds may be considered VIEs.
	As of September 30, 2014, we were an investor in a sponsored investment fund, considered to be a VIE, which was initially launched on December 31, 2013. Given the extent of our exposure to the variability of the net assets of the fund, we were deemed to be the fund’s primary beneficiary, and as a result we include the fund in our consolidated financial statements. The fund's activities consist primarily of active trading in various equity, fixed-income, currency, commodity and futures markets. Such activities are included in our consolidated financial statements.
	As of September 30, 2014, the aggregate assets and liabilities of this consolidated sponsored investment fund totaled $313 million and $260 million, respectively. As of December 31, 2013, the fund’s assets consisted solely of $50 million in cash.
	As of September 30, 2014 our potential maximum total exposure associated with the consolidated sponsored investment fund totaled $53 million and represented the value of our economic ownership interest in the fund. In the aggregate, we expect any financial losses that we realize over time from these seed investments to be limited to the actual fair value of the amount invested in the consolidated fund, which is based on the fair value of the underlying investment securities held by the funds. However, in the event of a fund wind-down, gross gains and losses of the fund may be recognized for financial accounting purposes in different periods during the time the fund is consolidated but not wholly owned. Although we expect the actual economic loss to be limited to the amount invested, our losses in any period could exceed the value of our economic interests in the fund and could exceed the value of our initial seed capital investment.
	Our conclusion to consolidate a sponsored investment 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 sponsored investment funds. In addition, neither creditors nor equity investors in the sponsored investment funds have any recourse to State Street’s general credit.
	As of September 30, 2014 and December 31, 2013, we managed certain sponsored investment 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 $40 million and $18 million as of September 30, 2014 and December 31, 2013, respectively, and represented the carrying value of our seed capital investment, which is recorded in either investment securities available for sale 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 seed capital investment in the unconsolidated fund.

Shareholders_Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
Shareholders' Equity	'
	Shareholders’ Equity
	Preferred Stock:
	In the three months ended March 31, 2014, we issued 30 million depositary shares, each representing a 1/4,000th ownership interest in a share of State Street’s fixed-to-floating-rate non-cumulative perpetual preferred stock, Series D, without par value, with a liquidation preference of $100,000 per share (equivalent to $25 per depositary share), which we refer to as our Series D preferred stock, in a public offering. The aggregate proceeds from the offering, net of underwriting discounts, commissions and other issuance costs, were approximately $742 million.
	On March 15, 2024, or any dividend payment date thereafter, the Series D preferred stock and corresponding depositary shares may be redeemed by us, in whole or in part, at a redemption price equal to $100,000 per share (equivalent to $25 per depositary share) plus any declared and unpaid dividends, without accumulation of any undeclared dividends. The Series D preferred stock and corresponding depositary shares may be redeemed at our option in whole, but not in part, prior to March 15, 2024, upon the occurrence of a regulatory capital treatment event, as defined in the certificate of designation with respect to the Series D preferred stock, at a redemption price equal to $100,000 per share (equivalent to $25 per depositary share) plus any declared and unpaid dividends, without accumulation of any undeclared dividends.
	In the three months ended September 30, 2014, we declared a dividend on our Series D preferred stock of $1,475 per share, or approximately $0.37 per depositary share, totaling approximately $11 million. In the nine months ended September 30, 2014, we declared aggregate dividends on our Series D preferred stock, Series D, of $3,130 per share, or approximately $0.78 per depositary share, totaling approximately $23 million. We did not declare a dividend on our Series D preferred stock in the three months ended March 31, 2014.
	In the three months ended September 30, 2014, we declared a dividend on our non-cumulative perpetual preferred stock, Series C (represented by depositary shares, each representing a 1/4,000th ownership interest in a share of State Street's non-cumulative perpetual preferred stock, Series C), referred to as our Series C preferred stock, of $1,313 per share, or approximately $0.33 per depositary share, totaling approximately $7 million. In the nine months ended September 30, 2014, we declared aggregate dividends on our Series C preferred stock of $3,939 per share, or approximately $0.99 per depositary share, totaling approximately $20 million. In the three months ended September 30, 2013, we declared a dividend on our Series C preferred stock of $1,313 per share, or approximately $0.33 per depositary share, totaling approximately $7 million. In the nine months ended September 30, 2013, we declared aggregate dividends on our Series C preferred stock of $3,939 per share, or approximately $0.98 per depositary share, totaling approximately $20 million.
	Dividends on shares of both our Series C and Series D preferred stock are not mandatory and are not cumulative. If declared, dividends will be payable on the liquidation preference of $100,000 per share quarterly in arrears on March 15, June 15, September 15 or December 15 of each year at an annual rate of 5.25% and 5.90%, respectively. If we issue additional shares of our Series C or Series D preferred stock after the original issue date, dividend rights with respect to such shares will commence from the original issue date of such additional shares. Dividends on our Series C and Series D preferred stock will not be declared to the extent that such declaration would cause us to fail to comply with applicable laws and regulations, including applicable federal regulatory capital guidelines.
	On September 15, 2017, or any dividend payment date thereafter, the Series C preferred stock and corresponding depositary shares may be redeemed by us, in whole or in part, at a redemption price equal to $100,000 per share (equivalent to $25 per depositary share) plus any declared and unpaid dividends, without accumulation of any undeclared dividends. The Series C preferred stock and corresponding depositary shares may be redeemed at our option, in whole or in part, prior to September 15, 2017, upon the occurrence of a regulatory capital treatment event, as defined in the certificate of designation with respect to the Series C preferred stock, at a redemption price equal to $100,000 per share (equivalent to $25 per depositary share) plus any declared and unpaid dividends, without accumulation of any undeclared dividends.
	Common Stock:
	In March 2014, our Board of Directors approved a common stock purchase program authorizing the purchase of up to $1.70 billion of our common stock through March 31, 2015. In the three months ended September 30, 2014, we purchased approximately 5.8 million shares of our common stock under that program, at an average per-share cost of $70.61 and an aggregate cost of approximately $410 million.
	In the nine months ended September 30, 2014, we purchased approximately 12.1 million shares of our common stock at an average per-share cost of $67.70 and an aggregate cost of approximately $820 million under that program, all in the three months ended June 30, 2014 and September 30, 2014. No shares were purchased under that program in the three months ended March 31, 2014.
	In the three months ended March 31, 2014, we purchased approximately 6.1 million shares of our common stock at an average cost of $69.14 per share and an aggregate cost of approximately $420 million, under a previous program approved by the Board in March 2013. As of March 31, 2014, no shares remained available for purchase under the March 2013 program.
	Under both programs, in the nine months ended September 30, 2014, we purchased in the aggregate approximately 18.2 million shares of our common stock at an average per-share cost of $68.18 and an aggregate cost of approximately $1.24 billion. Shares acquired under the March 2014 common stock purchase program which remained unissued as of September 30, 2014 were recorded as treasury stock in our consolidated statement of condition as of September 30, 2014.
	In the three months ended September 30, 2014, we declared a quarterly common stock dividend of $0.30 per share, totaling approximately $126 million. In the three months ended September 30, 2013, we declared a quarterly common stock dividend of $0.26 per share, totaling approximately $115 million. In the nine months ended September 30, 2014, we declared aggregate common stock dividends of $0.86 per share, totaling approximately $366 million, compared to aggregate common stock dividends of $0.78 per share, totaling approximately $350 million, declared in the nine months ended September 30, 2013.
	Accumulated Other Comprehensive Income (Loss):
	The following table presents the after-tax components of AOCI as of the dates indicated:
	(In millions)	September 30, 2014			December 31, 2013
	Net unrealized gains on cash flow hedges	$	217		$	161
	Net unrealized gains (losses) on available-for-sale securities portfolio	254			(56		)
	Net unrealized gains (losses) related to reclassified available-for-sale securities	46			(72		)
	Net unrealized gains (losses) on available-for-sale securities	300			(128		)
	Net unrealized losses on available-for-sale securities designated in fair value hedges	(106		)	(97		)
	Other-than-temporary impairment on available-for-sale securities related to factors other than credit	1			4
	Net unrealized losses on hedges of net investments in non-U.S. subsidiaries	(14		)	(14		)
	Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	(31		)	(47		)
	Net unrealized losses on retirement plans	(185		)	(203		)
	Foreign currency translation	(289		)	229
	Total	$	(107	)	$	(95	)
	In the nine months ended September 30, 2014, we realized net gains of $15 million, or $9 million net of related taxes as presented in the tables that follow, from sales of available-for-sale securities. Unrealized pre-tax losses of $43 million were included in AOCI as of December 31, 2013, net of deferred tax benefits of $17 million, related to these sales. In the nine months ended September 30, 2013, we realized net gains of $11 million, or $7 million net of related taxes as presented in the tables that follow, from sales of available-for-sale securities. Unrealized pre-tax gains of $25 million were included in AOCI as of December 31, 2012, net of deferred taxes of $10 million, related to these sales.
	The following tables present changes in AOCI by component, net of related taxes, for the periods indicated:
		Nine Months Ended September 30, 2014
	(In millions)	Net Unrealized Gains (Losses) on Cash Flow Hedges			Net Unrealized Gains (Losses) on Available-for-Sale Securities			Net Unrealized 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
	Beginning balance	$	161		$	(221	)	$	(14	)	$	(47	)	$	(203	)	$	229		$	(95	)
	Other comprehensive income (loss) before reclassifications	54			425			—			15			(1		)	(518		)	(25		)
	Amounts reclassified out of AOCI	2			(9		)	—			1			19			—			13
	Other comprehensive income (loss)	56			416			—			16			18			(518		)	(12		)
	Ending balance	$	217		$	195		$	(14	)	$	(31	)	$	(185	)	$	(289	)	$	(107	)
		Nine Months Ended September 30, 2013
	(In millions)	Net Unrealized Gains (Losses) on Cash Flow Hedges			Net Unrealized Gains (Losses) on Available-for-Sale Securities			Net Unrealized 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
	Beginning balance	$	69		$	519		$	(14	)	$	(65	)	$	(283	)	$	134		$	360
	Other comprehensive income (loss) before reclassifications	59			(578		)	—			11			(6		)	22			(492		)
	Amounts reclassified out of AOCI	2			(3		)	—			3			15			1			18
	Other comprehensive income (loss)	61			(581		)	—			14			9			23			(474		)
	Ending balance	$	130		$	(62	)	$	(14	)	$	(51	)	$	(274	)	$	157		$	(114	)
	The following tables present after-tax reclassifications out of AOCI for the periods indicated:
		Three Months Ended September 30,
		2014			2013
	(In millions)	Amounts Reclassified out of AOCI						Affected Line Item in Consolidated Statement of Income
	Cash flow hedges:
	Interest-rate contracts	$	1		$	—		Net interest revenue
	Available-for-sale securities:
	Net realized gains from sales of available-for-sale securities, net of related taxes of ($2)	—			(4		)	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 tax benefits of $1	—			1			Losses reclassified (from) to other comprehensive income
	Retirement plans:
	Amortization of actuarial losses, net of related tax benefits of $3 and $3, respectively	2			5			Compensation and employee benefits expenses
	Total reclassifications out of AOCI	$	3		$	2
		Nine Months Ended September 30,
		2014			2013
	(In millions)	Amounts Reclassified out of AOCI						Affected Line Item in Consolidated Statement of Income
	Cash flow hedges:
	Interest-rate contracts, net of related tax benefit of $1 and $1, respectively	$	2		$	2		Net interest revenue
	Available-for-sale securities:
Net realized gains from sales of available-for-sale securities, net of related taxes of ($6) and ($4), respectively	(9		)	(7		)	Net gains (losses) from sales of available-for-sale securities
Other-than-temporary impairment on available-for-sale securities related to factors other than credit, net of related tax benefit of $2	—			4			Losses reclassified (from) to other comprehensive income
Held-to-maturity securities:
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related tax benefit of $3 for 2013	1			3			Losses reclassified (from) to other comprehensive income
Retirement plans:
Amortization of actuarial losses, net of related taxes of ($2) and tax benefits of $9, respectively	19			15			Compensation and employee benefits expenses
Foreign currency translation:
Sales of non-U.S. entities, net of related taxes of ($1)	—			1			Processing fees and other revenue
Total reclassifications out of AOCI	$	13		$	18

Regulatory_Capital

Regulatory Capital	9 Months Ended
	Sep. 30, 2014
Banking and Thrift [Abstract]	'
Regulatory Capital	'
	Regulatory Capital
	As of December 31, 2013, we were subject to the generally applicable minimum regulatory capital requirements enforced by U.S. banking regulators, referred to as Basel I. These requirements were based on a 1988 international accord developed by the Basel Committee on Banking Supervision, or Basel Committee.
	In July 2013, U.S. banking regulators jointly issued a final rule to implement the Basel III framework in the U.S., referred to as the Basel III final rule, provisions of which become effective under a transition timetable which began on January 1, 2014, with full implementation required beginning on January 1, 2019. As provided in the Basel III final rule, banking organizations in their Basel II qualification period, or parallel run, were required to complete a superseding parallel run under Basel III.
	We were notified by the Federal Reserve on February 21, 2014 that we completed our parallel run and would be required to begin using the advanced approaches framework in the Basel III final rule in the determination of our risk-based capital requirements. Pursuant to this notification, we began to use the advanced approaches to calculate and disclose our risk-based capital ratios starting with the three months ended June 30, 2014.
	As required by the Dodd-Frank Wall Street Reform and Consumer Protection Act, or Dodd-Frank Act, enacted in 2010, 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, 2014, this capital floor is based on the provisions of Basel I, as adjusted by the final market risk capital rule issued by U.S. banking regulators in 2012.
	Beginning on January 1, 2014, we became subject to the provisions of the Basel III final rule that govern our calculation of regulatory capital, including transitional, or phase-in, provisions. Beginning with the three months ended June 30, 2014 and ending
	with December 31, 2014, the lower of our regulatory capital ratios calculated under the advanced approaches provisions of the Basel III final rule and those ratios calculated under the transitional provisions of Basel III (capital calculated in conformity with Basel III and risk-weighted assets calculated in conformity with Basel I as described above) will apply in the assessment of our capital adequacy for regulatory purposes.
	As of September 30, 2014, the minimum required regulatory capital ratios are as follows:
	•	common equity tier 1, or
	tier 1 common, risk-based capital - 4%;
	•	tier 1 risk-based capital - 5.5%;
	•	total risk-based capital - 8%; and
	•	tier 1 leverage - 4%
	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 September 30, 2014, State Street and State Street Bank exceeded all regulatory capital adequacy requirements to which they were subject. As of September 30, 2014, 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 September 30, 2014 that have changed the capital categorization of State Street Bank.
	The following table presents the regulatory capital structure, total risk-weighted assets and related 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
	(Dollars in millions)						Basel III Advanced Approach September 30, 2014(1)			Basel III Transitional September 30, 2014(2)			December 31, 2013(3)			Basel III Advanced Approach September 30, 2014(1)			Basel III Transitional September 30, 2014(2)			December 31, 2013(3)
	Common shareholders' equity:
	Common stock and related surplus						$	10,284		$	10,284		$	10,280		$	10,840		$	10,840		$	10,786
	Retained earnings						14,531			14,531			13,395			9,500			9,500			9,064
	Accumulated other comprehensive income (loss)						(264		)	(264		)	215			(220		)	(220		)	209
	Treasury stock, at cost						(4,785		)	(4,785		)	(3,693		)	—			—			—
	Total						19,766			19,766			20,197			20,120			20,120			20,059
	Regulatory capital adjustments:
	Goodwill and other intangible assets, net of associated deferred tax liabilities(4)						(5,942		)	(5,942		)	(7,743		)	(5,672		)	(5,672		)	(7,341		)
	Other adjustments						(43		)	(43		)	—			(132		)	(132		)	—
	Tier 1 common capital						13,781			13,781			12,454			14,316			14,316			12,718
	Preferred stock						1,233			1,233			491			—			—			—
	Trust preferred capital securities subject to phase-out from tier 1 capital						475			475			950			—			—			—
	Other adjustments						(171		)	(171		)	—			—			—			—
	Tier 1 capital						15,318			15,318			13,895			14,316			14,316			12,718
	Qualifying subordinated long-term debt						1,738			1,738			1,918			1,754			1,754			1,936
	Trust preferred capital securities phased out of tier 1 capital						475			475			NA			—			—			NA
	Other adjustments						3			3			(26		)	—			—			45
	Total capital						$	17,534		$	17,534		$	15,787		$	16,070		$	16,070		$	14,699
	Risk-weighted assets:
	Credit risk						$	67,915		$	90,377		$	78,864		$	60,610		$	87,150		$	76,197
	Operational risk						35,960			NA			NA			35,530			NA			NA
	Market risk						4,203			1,423			1,262			3,707			1,423			1,262
	Total risk-weighted assets						$	108,078		$	91,800		$	80,126		$	99,847		$	88,573		$	77,459
	Adjusted quarterly average assets						$	240,529		$	240,529		$	202,801		$	236,340		$	236,340		$	199,301
	Capital Ratios:		Minimum Requirements(5) 2014		Minimum Requirements(6) 2013
	Tier 1 common risk-based capital		4	%	NA		12.8		%	15		%	15.5		%	14.3		%	16.2		%	16.4		%
	Tier 1 risk-based capital		5.5		4	%	14.2			16.7			17.3			14.3			16.2			16.4
	Total risk-based capital		8		8		16.2			19.1			19.7			16.1			18.1			19
	Tier 1 leverage		4		4		6.4			6.4			6.9			6.1			6.1			6.4
	NA: Not applicable.
	(1) Tier 1 common capital, tier 1 capital and total capital ratios as of September 30, 2014 were calculated in conformity with the advanced approaches provisions of the Basel III final rule. Tier 1 leverage ratio as of September 30, 2014 was calculated in conformity with the Basel III final rule.
	(2) Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of September 30, 2014 were calculated in conformity with the transitional provisions of the Basel III final rule. Specifically, these ratios reflect tier 1 common, tier 1 and total capital (the numerator) calculated in conformity with the provisions of the Basel III final rule, and total risk-weighted assets or, with respect to the tier 1 leverage ratio, quarterly average assets (in both cases, the denominator), calculated in conformity with the provisions of Basel I.
	(3) Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of December 31, 2013 were calculated in conformity with the provisions of Basel I.
	(4) Amounts for State Street and State Street Bank as of September 30, 2014 consisted of goodwill, net of associated deferred tax liabilities, and 20% of other intangible assets, net of associated deferred tax liabilities, the latter phased in as a deduction from capital, in conformity with the Basel III final rule.
	(5) Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of September 30, 2014.
	(6) Minimum requirements listed, governed by Basel I, are as of December 31, 2013.

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	Derivative Financial Instruments
	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 and interest-rate options and interest-rate swaps, interest-rate forward contracts and interest-rate futures. Our derivative positions include derivative contracts held by a consolidated sponsored investment fund (refer to note 9).
	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 trading activities include our use of derivative financial instruments. One such risk-management measure is Value-at-Risk, or 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 is defined as the risk of financial loss if a borrower or counterparty is either unable or unwilling to repay borrowings or settle a transaction in accordance with the underlying contractual terms. We manage credit and counterparty risk by performing credit reviews, maintaining individual counterparty limits, entering into netting arrangements and requiring the receipt of collateral. Collateral requirements are determined after a review of the creditworthiness of each counterparty, and these requirements are monitored and adjusted daily. Collateral is generally held in the form of cash or highly liquid U.S. government securities. We may be required to provide collateral to the counterparty in connection with our entry into derivative financial instruments. 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 September 30, 2014 and December 31, 2013, we had recorded approximately $1.37 billion and $2.58 billion, respectively, of cash collateral received from counterparties and approximately $4.32 billion and $3.36 billion, respectively, of cash collateral provided to counterparties in connection with derivative financial instruments in our consolidated statement of condition.
	We enter into master netting agreements with many of our derivative counterparties, and we have elected to net derivative assets and liabilities, including cash collateral received or deposited, which are subject to those agreements. Certain of these agreements contain credit risk-related contingent features in which the counterparty has the right to declare State Street 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 September 30, 2014 totaled approximately $2.49 billion, against which we posted aggregate collateral of approximately $110 million, with the latter amount due to timing differences with respect to the mark-to-market valuation of the collateral. If State Street’s 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 as of September 30, 2014 was approximately $2.38 billion. Such accelerated settlement would not affect our consolidated results of operations.
	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 net interest revenue. 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 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 7, 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.
	In 2013 and 2014, we granted 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. 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 and options (for example, interest-rate caps and floors). Interest-rate swap agreements alter the interest-rate characteristics of specific balance sheet assets or liabilities. When appropriate, forward-rate agreements, options on swaps, and exchange-traded futures and options are also used. Our hedging relationships are formally designated, and qualify for hedge accounting, as fair value or cash flow hedges.
	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 fair value hedges and the gains and losses on the 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.
	We have entered into interest-rate swap agreements to modify our interest revenue from certain available-for-sale investment securities from a fixed rate to a floating rate. The hedged securities had a weighted-average life of approximately 6.1 years as of September 30, 2014, compared to 6.5 years as of December 31, 2013. These securities are hedged with interest-rate swap contracts of similar maturity, repricing and fixed-rate coupons. The interest-rate swap contracts convert the interest revenue 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 two senior notes and one subordinated note from fixed rates to floating rates. The senior notes mature in 2018 and 2023 and pay fixed interest at annual rates of 1.35% and 3.70%, respectively. The subordinated note matures in 2023 and pays fixed interest at a 3.10% annual rate. The senior and subordinated notes are hedged with interest-rate swap contracts with notional amounts, maturities and fixed-rate coupon terms that align with the hedged 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.
	We have entered into forward foreign exchange contracts to hedge the change in fair value attributable to foreign exchange movements in the funding of non-functional currency-denominated investment securities. 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 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. 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 net interest 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 variability of cash flows of the forecast transaction.
	We have entered into an interest-rate swap agreement to modify our interest revenue from an available-for-sale debt security from a floating rate to a fixed rate. The hedged security had a remaining life of approximately 1 month as of September 30, 2014, compared to approximately 10 months as of December 31, 2013. The security is hedged with an interest-rate swap contract of similar maturity, repricing and other characteristics. The interest-rate swap contract converts the interest revenue from a floating rate to a fixed rate, thereby mitigating our exposure to fluctuations in the cash flows of the security attributable to changes in the benchmark interest rate.
	We have entered into foreign exchange contracts to hedge the change in cash flows attributable to foreign exchange movements in the funding of non-functional 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.
	For cash flow hedges, any changes in the fair value of the derivative financial instruments remain in AOCI, and are generally recorded in our consolidated statement of income in future periods when earnings are affected by the variability of the hedged cash flow.
	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)	September 30,				December 31,
		2014				2013
	Derivatives not designated as hedging instruments:
	Interest-rate contracts:
	Swap agreements and forwards	$	842			$	1,023
	Options and caps purchased	9				27
	Options and caps written	9				27
	Futures	6,389				3,282
	Foreign exchange contracts:
	Forward, swap and spot	1,307,605				1,124,355
	Options purchased	2,923				1,666
	Options written	2,399				1,423
	Futures	19				—
	Credit derivative contracts:
	Credit swap agreements	192				141
	Total return swap agreements(1)	8				—
	Commodity and equity contracts:
	Commodity(1)	555				2
	Equity(1)	86				1
	Other:
	Stable value contracts	24,305				24,906
	Deferred cash awards(2)	227				42
	Derivatives designated as hedging instruments:
	Interest-rate contracts:
	Swap agreements	5,212				5,221
	Foreign exchange contracts:
	Forward and swap	2,693				2,783
	(1) Primarily composed of positions held by a consolidated sponsored investment fund, more fully described in note 9.
	(2) Represents grants of deferred cash awards to employees; refer to discussion in this note under "Derivatives Not Designated as Hedging Instruments."
	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 table presents the aggregate notional amounts of these interest-rate contracts and the related assets or liabilities being hedged as of the dates indicated:
		September 30, 2014
	(In millions)	Fair				Cash				Total
		Value				Flow
		Hedges				Hedges
	Investment securities available for sale	$	2,583			$	129			$	2,712
	Long-term debt(1)	2,500				—				2,500
	Total	$	5,083			$	129			$	5,212
		December 31, 2013
(In millions)	Fair				Cash				Total
	Value				Flow
	Hedges				Hedges
Investment securities available for sale	$	2,589			$	132			$	2,721
Long-term debt(1)	2,500				—				2,500
Total	$	5,089			$	132			$	5,221
(1) As of September 30, 2014, these fair value hedges increased the carrying value of long-term debt presented in our consolidated statement of condition by $25 million. As of December 31, 2013, these fair value hedges decreased the carrying value of long-term debt presented in our consolidated statement of condition by $35 million.
The following tables present 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:
	Three Months Ended September 30,
	2014						2013
	Contractual			Rate Including			Contractual			Rate Including
	Rates			Impact of Hedges			Rates			Impact of Hedges
Long-term debt	3.44	%		2.64	%		3.34	%		2.67	%
	Nine Months Ended September 30,
	2014						2013
	Contractual			Rate Including			Contractual			Rate Including
	Rates			Impact of Hedges			Rates			Impact of Hedges
Long-term debt	3.45	%		2.66	%		3.49	%		2.77	%
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 disclosed in note 2.
	Derivatives - Assets
	Balance Sheet		Fair Value
	Location
(In millions)			September 30, 2014				December 31, 2013
Derivatives not designated as hedging instruments:
Foreign exchange contracts	Other assets		$	16,434			$	11,552
Interest-rate contracts	Other assets		16				29
Other derivative contracts	Other assets		4				1
Total			$	16,454			$	11,582
Derivatives designated as hedging instruments:
Foreign exchange contracts	Other assets		$	431			$	359
Interest-rate contracts	Other assets		47				36
Total			$	478			$	395
	Derivatives - Liabilities
	Balance Sheet		Fair Value
	Location
(In millions)			September 30, 2014				December 31, 2013
Derivatives not designated as hedging instruments:
Foreign exchange contracts	Other liabilities		$	16,556			$	11,428
Other derivative contracts	Other liabilities		73				23
Interest-rate contracts	Other liabilities		16				29
Total			$	16,645			$	11,480
Derivatives designated as hedging instruments:
Interest-rate contracts	Other liabilities		$	225			$	302
Foreign exchange contracts	Other liabilities		3				43
Total			$	228			$	345
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		Amount of Gain (Loss) on Derivative Recognized
	Derivative in Consolidated		in Consolidated Statement of Income
	Statement of Income
			Three Months Ended September 30,								Nine Months Ended September 30,
(In millions)			2014				2013				2014			2013
Derivatives not designated as hedging instruments:
Foreign exchange contracts	Trading services revenue		$	163			$	147			$	441		$	461
Interest-rate contracts	Trading services revenue		1				—				—			3
Credit derivative contracts	Processing fees and other revenue		—				1				(1		)	1
Other derivative contracts	Trading services revenue		1				—				1			—
Total			$	165			$	148			$	441		$	465
	Location of (Gain) Loss on		Amount of (Gain) Loss on Derivative Recognized
	Derivative in Consolidated		in Consolidated Statement of Income
	Statement of Income
			Three Months Ended September 30,								Nine Months Ended September 30,
(In millions)			2014				2013				2014			2013
Derivatives not designated as hedging instruments:
Other derivative contracts	Compensation and employee benefits		$	18			$	4			$	89		$	10
Total			$	18			$	4			$	89		$	10
	Location of Gain (Loss) on Derivative in Consolidated Statement of Income		Amount of Gain								Hedged Item in Fair Value Hedging Relationship		Location of Gain (Loss) on Hedged Item in Consolidated Statement of Income	Amount of Gain
			(Loss) on Derivative											(Loss) on Hedged
			Recognized in											Item Recognized in
			Consolidated											Consolidated
			Statement of Income											Statement of Income
(In millions)			Three Months Ended September 30, 2014				Nine Months Ended September 30, 2014							Three Months Ended September 30, 2014			Nine Months Ended September 30, 2014
Derivatives designated as fair value hedges:
Foreign exchange contracts	Processing fees and		$	(82	)		$	(22	)		Investment securities		Processing fees and	$	82		$	22
	other revenue												other revenue
Interest-rate contracts	Processing fees and		24				(17		)		Available-for-sale securities		Processing fees and	(23		)	15
	other revenue												other revenue(1)
Interest-rate contracts	Processing fees and		(8		)		88				Long-term debt		Processing fees and	9			(80		)
	other revenue												other revenue
Total			$	(66	)		$	49						$	68		$	(43	)
	Location of Gain (Loss) on Derivative in Consolidated Statement of Income		Amount of Gain								Hedged Item in Fair Value Hedging Relationship		Location of Gain (Loss) on Hedged Item in Consolidated Statement of Income	Amount of Gain
			(Loss) on Derivative											(Loss) on Hedged
			Recognized in											Item Recognized in
			Consolidated											Consolidated
			Statement of Income											Statement of Income
(In millions)			Three Months Ended September 30, 2013				Nine Months Ended September 30, 2013							Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
Derivatives designated as fair value hedges:
Foreign exchange contracts	Processing fees and		$	20			$	(135	)		Investment securities		Processing fees and	$	(20	)	$	135
	other revenue												other revenue
Interest-rate contracts	Processing fees and		(14		)		(146		)		Long-term debt		Processing fees and	12			133
	other revenue												other revenue
Interest-rate contracts	Processing fees and		(6		)		15				Available-for-sale securities		Processing fees and	7			(15		)
	other revenue												other revenue(1)
Total			$	—			$	(266	)					$	(1	)	$	253
(1) Represents amounts reclassified out of other comprehensive income, or OCI. For the three and nine months ended September 30, 2014, $14 million of unrealized gains and $9 million of unrealized losses, respectively, on available-for-sale securities designated in fair value hedges were recognized in OCI. For the three and nine months ended September 30, 2013, $1 million and $61 million, respectively, of unrealized gains on available-for-sale 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 net interest revenue, represent hedge ineffectiveness.
	Amount of Gain								Location of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income		Amount of Gain						Location of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		Amount of Gain
	(Loss) on Derivative										(Loss) Reclassified								(Loss) on Derivative
	Recognized in Other										from OCI to								Recognized in
	Comprehensive										Consolidated								Consolidated
	Income										Statement of Income								Statement of Income
	Three Months Ended September 30, 2014				Nine Months Ended September 30, 2014						Three Months Ended September 30, 2014			Nine Months Ended September 30, 2014					Three Months Ended September 30, 2014		Nine Months Ended September 30, 2014
(In millions)
Derivatives designated as cash flow hedges:
Interest-rate contracts	$	(1	)		$	(3	)		Net interest revenue		$	(1	)	$	(3	)	Net interest revenue		$	1	$	3
Foreign exchange contracts	92				28				Net interest revenue		—			—			Net interest revenue		2		4
Total	$	91			$	25					$	(1	)	$	(3	)			$	3	$	7
	Amount of Gain								Location of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income		Amount of Gain						Location of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		Amount of Gain
	(Loss) on Derivative										(Loss) Reclassified								(Loss) on Derivative
	Recognized in Other										from OCI to								Recognized in
	Comprehensive										Consolidated								Consolidated
	Income										Statement of Income								Statement of Income
	Three Months Ended September 30, 2013				Nine Months Ended September 30, 2013						Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013					Three Months Ended September 30, 2013		Nine Months Ended September 30, 2013
(In millions)
Derivatives designated as cash flow hedges:
Interest-rate contracts	$	(1	)		$	10			Net interest revenue		$	(1	)	$	(3	)	Net interest revenue		$	1	$	3
Foreign exchange contracts	(55		)		98				Net interest revenue		—			—			Net interest revenue		—		5
Total	$	(56	)		$	108					$	(1	)	$	(3	)			$	1	$	8

Offsetting_Arrangements

Offsetting Arrangements	9 Months Ended
	Sep. 30, 2014
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 basis to conclude that a legally enforceable netting arrangement exists 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 September 30, 2014 and December 31, 2013, the fair value of securities received as collateral where we are permitted to transfer or re-pledge the securities totaled $2.94 billion and $5.64 billion, respectively, and the fair value of the portion that had been transferred or re-pledged as of the same date was $370 million and $1.77 billion, 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:	30-Sep-14								31-Dec-13
	(In millions)	Gross Amounts of Recognized Assets(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Assets Presented in Statement of Condition			Gross Amounts of Recognized Assets(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Assets Presented in Statement of Condition
	Derivatives:
	Foreign exchange contracts	$	16,865	$	(7,345	)	$	9,520		$	11,911	$	(4,514	)	$	7,397
	Interest-rate contracts	63		(34		)	29			65		(59		)	6
	Other derivative contracts	4		—			4			1		—			1
	Cash collateral netting	—		(841		)	(841		)	—		(1,928		)	(1,928		)
	Total derivatives	$	16,932	$	(8,220	)	$	8,712		$	11,977	$	(6,501	)	$	5,476
	Other financial instruments:
	Resale agreements and securities borrowing(3)	$	48,078	$	(29,692	)	$	18,386		$	48,221	$	(30,700	)	$	17,521
	Total derivatives and other financial instruments	$	65,010	$	(37,912	)	$	27,098		$	60,198	$	(37,201	)	$	22,997
	(1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
	(2) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(3) Included in the $18,386 million as of September 30, 2014 were $2,603 million of resale agreements and $15,783 million of collateral provided related to securities borrowing. Included in the $17,521 million as of December 31, 2013 were $6,230 million of resale agreements and $11,291 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 7 for additional information with respect to principal securities finance transactions.
		30-Sep-14										31-Dec-13
				Gross Amounts Not Offset in Statement of Condition(1)											Gross Amounts Not Offset in Statement of Condition(1)
	(In millions)	Net Amount of Assets Presented in Statement of Condition		Counterparty Netting			Collateral Received			Net Amount(2)		Net Amount of Assets Presented in Statement of Condition			Counterparty Netting			Collateral Received			Net Amount(2)
	Derivatives	$	8,712	$	—		$	(644	)	$	8,068	$	5,476		$	—		$	(181	)	$	5,295
	Resale agreements and securities borrowing	18,386		(108		)	(18,185		)	93		17,521			(131		)	(14,983		)	2,407
	Total	$	27,098	$	(108	)	$	(18,829	)	$	8,161	$	22,997		$	(131	)	$	(15,164	)	$	7,702
	(1) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(2) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.
	The following tables present information about the offsetting of liabilities related to derivative contracts and secured financing transactions, as of the dates indicated:
	Liabilities:	30-Sep-14								31-Dec-13
	(In millions)	Gross Amounts of Recognized Liabilities(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Liabilities Presented in Statement of Condition			Gross Amounts of Recognized Liabilities(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Liabilities Presented in Statement of Condition
	Derivatives:
	Foreign exchange contracts	$	16,559	$	(7,345	)	$	9,214		$	11,471	$	(4,514	)	$	6,957
	Interest-rate contracts	241		(34		)	207			331		(59		)	272
	Other derivative contracts	73		—			73			9		—			9
	Cash collateral netting	—		(2,581		)	(2,581		)	—		(979		)	(979		)
	Total derivatives	$	16,873	$	(9,960	)	$	6,913		$	11,811	$	(5,552	)	$	6,259
	Other financial instruments:
	Repurchase agreements and securities lending(3)	$	46,089	$	(29,692	)	$	16,397		$	45,273	$	(30,700	)	$	14,573
	Total derivatives and other financial instruments	$	62,962	$	(39,652	)	$	23,310		$	57,084	$	(36,252	)	$	20,832
	(1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
	(2) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(3) Included in the $16,397 million as of September 30, 2014 were $9,385 million of repurchase agreements and $7,012 million of collateral received related to securities lending. Included in the $14,573 million as of December 31, 2013 were $7,953 million of repurchase agreements and $6,620 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 liabilities, respectively, in our consolidated statement of condition. Refer to note 7 for additional information with respect to principal securities finance transactions.
		30-Sep-14										31-Dec-13
				Gross Amounts Not Offset in Statement of Condition(1)											Gross Amounts Not Offset in Statement of Condition(1)
	(In millions)	Net Amount of Liabilities Presented in Statement of Condition		Counterparty Netting			Collateral Provided			Net Amount(2)		Net Amount of Liabilities Presented in Statement of Condition			Counterparty Netting			Collateral Provided			Net Amount(2)
	Derivatives	$	6,913	$	—		$	(78	)	$	6,835	$	6,259		$	—		$	(6	)	$	6,253
	Repurchase agreements and securities lending	16,397		(108		)	(14,173		)	2,116		14,573			(131		)	(13,036		)	1,406
	Total	$	23,310	$	(108	)	$	(14,251	)	$	8,951	$	20,832		$	(131	)	$	(13,042	)	$	7,659
	(1) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(2) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.

Net_Interest_Revenue

Net Interest Revenue	9 Months Ended
	Sep. 30, 2014
Net Interest Revenue [Abstract]	'
Net Interest Revenue	'
	Net Interest Revenue
	The following table presents the components of interest revenue and interest expense, and related net interest revenue, for the periods indicated:
		Three Months Ended September 30,				Nine Months Ended September 30,
	(In millions)	2014		2013		2014		2013
	Interest revenue:
	Deposits with banks	$	53	$	29	$	138	$	91
	Investment securities:
	U.S. Treasury and federal agencies	165		165		493		542
	State and political subdivisions	58		59		173		164
	Other investments	320		323		957		1,003
	Securities purchased under resale agreements	9		8		27		33
	Loans and leases	64		58		183		193
	Other interest-earning assets	2		1		5		4
	Total interest revenue	671		643		1,976		2,030
	Interest expense:
	Deposits	33		17		66		78
	Short-term borrowings	—		15		4		46
	Long-term debt	60		59		186		169
	Other interest-bearing liabilities	8		6		34		19
	Total interest expense	101		97		290		312
	Net interest revenue	$	570	$	546	$	1,686	$	1,718

Expenses

Expenses	9 Months Ended
	Sep. 30, 2014
Other Expenses [Abstract]	'
Expenses	'
	Expenses
	Severance Costs:
	We recorded $74 million of net severance costs in the nine months ended September 30, 2014. These severance costs were the result of staff reductions associated with the realignment of our cost base, and were recorded in compensation and employee benefits expenses in our consolidated statement of income.
	Acquisition and Restructuring Costs:
	The following table presents net acquisition and restructuring costs recorded in the periods indicated:
			Three Months Ended September 30,						Nine Months Ended September 30,
	(In millions)		2014			2013			2014			2013
	Acquisition costs		$	12		$	18		$	48		$	52
	Restructuring charges, net		8			12			33			22
	Total acquisition and restructuring costs		$	20		$	30		$	81		$	74
	Acquisition Costs
	Acquisition costs recorded in the three and nine months ended September 30, 2014 and the three and nine months ended September 30, 2013 were related to previously disclosed acquisitions.
	Restructuring Charges
	Information with respect to our Business Operations and Information Technology Transformation program and our 2012 expense control measures, including charges, employee reductions and aggregate activity in the related accruals, is provided in the two sections that follow.
	Business Operations and Information Technology Transformation Program
	In November 2010, we announced a global multi-year Business Operations and Information Technology Transformation program. The program includes operational, information technology and targeted cost initiatives, including plans related to reductions in both staff and occupancy costs. To date, we have recorded aggregate restructuring charges of $402 million in our consolidated statement of income, composed of $156 million in 2010, $133 million in 2011, $67 million in 2012, $25 million in 2013 and $21 million in the nine months ended September 30, 2014.
	The charges related to the program included costs related to severance, benefits and outplacement services, as well as costs which resulted from actions taken to reduce our occupancy costs through the consolidation of leases and properties. The charges also included costs related to information technology, including transition fees associated with the expansion of our use of third-party service providers associated with components of our information technology infrastructure and application maintenance and support.
	In 2010, in connection with the program, we initiated the involuntary termination of 1,400 employees, or approximately 5% of our global workforce, which we completed by the end of 2011. In addition, in connection with our announcement in 2011 of the expansion of our use of third-party service providers associated with our information technology infrastructure and application maintenance and support, as well as the continued execution of the business operations transformation component of the program, we identified 1,574 additional involuntary terminations. As of September 30, 2014, we eliminated 1,522 of these positions.
	Expense Control Measures
	In December 2012, in connection with expense control measures designed to better align our expenses to our business strategy and related outlook for 2013, we identified additional targeted staff reductions. As a result of these actions, we have recorded aggregate pre-tax restructuring charges of $133 million in 2012, $3 million in 2013 and $12 million in the nine months ended September 30, 2014 in our consolidated statement of income. Employee-related costs included severance, benefits and outplacement services. Costs for asset and other write-offs were primarily related to contract terminations. We originally identified involuntary terminations of 960 employees (630 positions after replacements).  As of March 31, 2014, we substantially completed these reductions.
	Aggregate Restructuring-Related Accrual Activity
	The following table presents aggregate activity associated with accruals that resulted from the charges associated with the Business Operations and Information Technology Transformation program and expense control measures:
	(In millions)	Employee-			Real Estate Consolidation			Asset and Other Write-Offs			Total
		Related
		Costs
	Balance as of December 31, 2013	$	50		$	49		$	7		$	106
	Additional accruals for Business Operations and Information Technology Transformation program	14			7			—			21
	Additional accruals for 2012 expense control measures	1			—			11			12
	Payments and adjustments	(37		)	(36		)	(7		)	(80		)
	Balance as of September 30, 2014	$	28		$	20		$	11		$	59

Earnings_Per_Common_Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Common Share	'
	Earnings Per Common Share
	The following tables present the computation of basic and diluted earnings per common share for the periods indicated:
		Three Months Ended September 30,
	(Dollars in millions, except per share amounts)	2014			2013
	Net income	$	560		$	540
	Less:
	Preferred stock dividends	(18		)	(7		)
	Dividends and undistributed earnings allocated to participating securities(1)	—			(2		)
	Net income available to common shareholders	$	542		$	531
	Average common shares outstanding (in thousands):
	Basic average common shares	421,974			442,860
	Effect of dilutive securities: common stock options and common stock awards	7,762			9,294
	Diluted average common shares	429,736			452,154
	Anti-dilutive securities(2)	876			1,788
	Earnings per Common Share:
	Basic	$	1.28		$	1.2
	Diluted(3)	1.26			1.17
		Nine Months Ended September 30,
	(Dollars in millions, except per share amounts)	2014			2013
	Net income	$	1,545		$	1,583
	Less:
	Preferred stock dividends	(43		)	(20		)
	Dividends and undistributed earnings allocated to participating securities(1)	(2		)	(6		)
	Net income available to common shareholders	$	1,500		$	1,557
	Average common shares outstanding (in thousands):
	Basic average common shares	426,775			449,742
	Effect of dilutive securities: common stock options and common stock awards	7,735			8,650
	Diluted average common shares	434,510			458,392
	Anti-dilutive securities(2)	1,502			2,384
	Earnings per Common Share:
	Basic	$	3.52		$	3.46
	Diluted(3)	3.45			3.4
	(1) Represented the portion of net income available to common equity allocated to participating securities, composed of fully vested deferred director stock and unvested restricted stock that contain non-forfeitable rights to dividends during the vesting period on a basis equivalent to dividends paid to common shareholders.
	(2) Represented common stock options and other equity-based awards outstanding but not included in the computation of diluted average common shares, because their effect was anti-dilutive.
	(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	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Line of Business Information	'
	Line of Business Information
	We have two lines of business: Investment Servicing and Investment Management. Given our services and management organization, 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. Information about our two lines of business, as well as revenues, expenses and capital allocation methodologies associated with them, is provided in note 25 to the consolidated financial statements included in our 2013 Form 10-K.
	The following is a summary of our line-of-business results for the periods indicated. The “Other” column for the three and nine months ended September 30, 2014 included net costs of $14 million and $157 million, respectively, composed of the following -
	Three months ended September 30, 2014 -
	•	Severance cost credits of $2 million associated with prior accruals for staff reductions;
	•	Net acquisition and restructuring costs of $20 million; and
	•	Credits to provisions for litigation exposure and other costs of $4 million.
	Nine months ended September 30, 2014 -
	•	Net severance costs associated with staff reductions of $74 million;
	•	Net acquisition and restructuring costs of $81 million; and
	•	Provisions for litigation exposure and other costs of $2 million.
	The “Other” column for the three and nine months ended September 30, 2013 included costs of $35 million and $94 million, respectively, composed of the following -
	Three months ended September 30, 2013 -
	•	Net acquisition and restructuring costs of $30 million; and
	•	Net provisions for litigation exposure and other costs of $5 million.
	Nine months ended September 30, 2013 -
	•	Net acquisition and restructuring costs of $74 million; and
	•	Net provisions for litigation exposure and other costs of $20 million.
	The amounts in the “Other” columns were not allocated to State Street's business lines. Results for the 2013 periods reflect reclassifications, for comparative purposes, related to management changes in methodologies associated with allocations of revenue and expenses reflected in line-of-business results for 2014.
		Three Months Ended September 30,
		Investment						Investment						Other						Total
		Servicing						Management
		2014			2013			2014			2013			2014			2013			2014			2013
	(Dollars in millions,
	except where otherwise noted)
	Fee revenue:
	Servicing fees	$	1,302		$	1,211		$	—		$	—		$	—		$	—		$	1,302		$	1,211
	Management fees	—			—			316			276			—			—			316			276
	Trading services	266			251			12			14			—			—			278			265
	Securities finance	99			74			—			—			—			—			99			74
	Processing fees and other	25			52			(8		)	5			—			—			17			57
	Total fee revenue	1,692			1,588			320			295			—			—			2,012			1,883
	Net interest revenue	551			527			19			19			—			—			570			546
	Gains (losses) related to investment securities, net	—			(4		)	—			—			—			—			—			(4		)
	Total revenue	2,243			2,111			339			314			—			—			2,582			2,425
	Provision for loan losses	2			—			—			—			—			—			2			—
	Total expenses	1,639			1,500			239			187			14			35			1,892			1,722
	Income before income tax expense	$	602		$	611		$	100		$	127		$	(14	)	$	(35	)	$	688		$	703
	Pre-tax margin	27		%	29		%	29		%	40		%							27		%	29		%
	Average assets (in billions)	$	243.2		$	197.7		$	4.1		$	3.6								$	247.3		$	201.3
		Nine Months Ended September 30,
		Investment						Investment						Other						Total
		Servicing						Management
		2014			2013			2014			2013			2014			2013			2014			2013
	(Dollars in millions,
	except where otherwise noted)
	Fee revenue:
	Servicing fees	$	3,828		$	3,587		$	—		$	—		$	—		$	—		$	3,828		$	3,587
	Management fees	—			—			908			816			—			—			908			816
	Trading services	756			803			35			55			—			—			791			858
	Securities finance	331			283			—			—			—			—			331			283
	Processing fees and other	122			157			(5		)	10			—			—			117			167
	Total fee revenue	5,037			4,830			938			881			—			—			5,975			5,711
	Net interest revenue	1,634			1,655			52			63			—			—			1,686			1,718
	Gains (losses) related to investment securities, net	4			(9		)	—			—			—			—			4			(9		)
	Total revenue	6,675			6,476			990			944			—			—			7,665			7,420
	Provision for loan losses	6			—			—			—			—			—			6			—
	Total expenses	4,905			4,639			708			613			157			94			5,770			5,346
	Income before income tax expense	$	1,764		$	1,837		$	282		$	331		$	(157	)	$	(94	)	$	1,889		$	2,074
	Pre-tax margin	26		%	28		%	28		%	35		%							25		%	28		%
	Average assets (in billions)	$	229		$	201.9		$	3.6		$	3.8								$	232.6		$	205.7

NonUS_Activities

Non-U.S. Activities	9 Months Ended
	Sep. 30, 2014
Segments, Geographical Areas [Abstract]	'
Non-U.S. Activities	'
	Non-U.S. Activities
	We generally define our non-U.S. activities as those revenue-producing business activities that arise from clients domiciled 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 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. Interest expense allocations are based on our internal funds transfer pricing methodology.
	The following table presents our non-U.S. financial results for the periods indicated.
		Three Months Ended September 30,
	(In millions)	2014		2013
	Total fee revenue	$	862	$	771
	Net interest revenue	325		306
	Gains (losses) related to investment securities, net	1		(2		)
	Total revenue	1,188		1,075
	Expenses	791		786
	Income before income taxes	397		289
	Income tax expense	96		74
	Net income	$	301	$	215
		Nine Months Ended September 30,
	(In millions)	2014		2013
	Total fee revenue	$	2,488	$	2,347
	Net interest revenue	991		874
	Gains (losses) related to investment securities, net	6		(12		)
	Total revenue	3,485		3,209
	Expenses	2,443		2,279
	Income before income taxes	1,042		930
	Income tax expense	248		228
	Net income	$	794	$	702
	The following table presents the significant components of our non-U.S. assets as of the dates indicated, based on the domicile of the underlying counterparties:
	(In millions)	September 30, 2014		December 31, 2013
	Interest-bearing deposits with banks	$	9,828	$	9,584
	Investment securities	30,791		31,522
	Other assets	17,326		16,778
	Total non-U.S. assets	$	57,945	$	57,884

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Recent Accounting Developments	'
	Recent Accounting Developments:
	In August 2014, the FASB issued an amendment to GAAP that requires management to evaluate whether there is substantial doubt about the entity’s ability to continue as a going concern and, if so, disclose that fact. The amendment is effective, for State Street, for its annual consolidated financial statements as of December 31, 2016 and interim periods thereafter. Our adoption of the amendment will not have a material effect on our consolidated financial statements.
	In June 2014, the FASB issued an amendment to GAAP for “repo-to-maturity” transactions and repurchase agreements executed as repurchase financings. The amendment requires enhanced disclosure for repurchase agreements and securities lending transactions accounted for as secured borrowings and for certain transfers of financial assets. The amendment is effective, for State Street, beginning on January 1, 2015. Our adoption of the amendment is not expected to have a material effect on our consolidated financial statements.
	In May 2014, the FASB issued an amendment to GAAP that provides for a single comprehensive model to be applied in the accounting for revenue arising from contracts with clients. In applying this model, an entity would recognize revenue that represents the transfer of promised goods or services to clients in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendment supersedes most current revenue recognition guidance, including industry-specific guidance. The amendment is effective, for State Street, beginning on January 1, 2017, and must be applied retrospectively. Early adoption is prohibited. We are currently assessing the potential impact of this amendment on our consolidated financial statements.
	In April 2014, the FASB issued an amendment to GAAP that revises the criteria for the treatment and disclosure of discontinued operations. The amendment allows entities to have significant continuing involvement and continuing cash flows with the discontinued operation, but requires additional disclosure for discontinued operations and disclosure for disposals deemed to be material that do not meet the definition of a discontinued operation. The presentation and disclosure requirements are effective, for State Street, beginning on January 1, 2015, and are required to be applied prospectively to discontinued operations occurring after that date.
	In January 2014, the FASB issued an amendment to GAAP that allows an investor in an affordable housing project, if the project meets certain defined conditions, to amortize the cost of their investment in proportion to the tax credits and other tax benefits they receive, and reflect it as part of income tax expense rather than as revenue from operations. The amendment is effective, for State Street, for interim and annual periods beginning after December 15, 2014, with early adoption permitted, and must be applied retrospectively. At this time, we have not chosen to early-adopt the amendment as we continue to assess the potential impact of this amendment on our consolidated financial statements.
Asset-Backed Securitization Trusts	'
	We invest in various forms of asset-backed securities, which we carry in our investment securities portfolio. These asset-backed securities meet the GAAP definition of asset securitization entities, which are considered to be variable interest entities, or VIEs, as defined by GAAP. We are not considered to be the primary beneficiary of these VIEs, as defined by GAAP, since we do not have control over their activities. Additional information about our asset-backed securities is provided in note 3.
Tax-Exempt Investment Program	'
	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 investment securities available for sale and other short-term borrowings. We may also provide liquidity and re-marketing services to the trusts. As of September 30, 2014 and December 31, 2013, we carried investment securities available for sale, composed of securities related to state and political subdivisions, with a fair value of $2.30 billion and $2.33 billion, respectively, and other short-term borrowings of $1.89 billion and $1.95 billion, respectively, in our consolidated statement of condition in connection with these trusts.
	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 trusts to third-party investors and to State Street as residual holder. These transfers do not meet the de-recognition criteria defined by GAAP, and therefore, are recorded in our consolidated financial statements. The trusts had a weighted-average life of approximately 6.1 years as of September 30, 2014, compared to approximately 6.5 years as of December 31, 2013.
	Under separate legal agreements, we provide standby bond-purchase agreements to these trusts and, with respect to certain securities, letters of credit. Our commitments to the trusts under these standby bond-purchase agreements and letters of credit totaled $1.92 billion and $684 million, respectively, as of September 30, 2014, none of which was utilized as of that date. In the event that our obligations under these agreements 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.

Fair_Value_Tables

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	'
	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. No transfers of financial assets or liabilities between levels 1 and 2 occurred in the nine months ended September 30, 2014 or the year ended December 31, 2013.
		Fair-Value Measurements on a Recurring Basis
		as of September 30, 2014
	(In millions)	Quoted Market			Pricing Methods			Pricing Methods				Impact of Netting(1)			Total Net
		Prices in Active			with Significant			with Significant							Carrying Value
		Markets			Observable			Unobservable							in Consolidated
		(Level 1)			Market Inputs			Market Inputs							Statement of
					(Level 2)			(Level 3)							Condition
	Assets:
	Trading account assets:
	U.S. government securities	$	37		$	—		$	—						$	37
	Non-U.S. government securities	479			—			—							479
	Other	52			465			—							517
	Total trading account assets	568			465			—							1,033
	Investment securities available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	10,139			625			—							10,764
	Mortgage-backed securities	—			20,941			260							21,201
	Asset-backed securities:
	Student loans	—			12,540			266							12,806
	Credit cards	—			3,111			—							3,111
	Sub-prime	—			997			—							997
	Other	—			399			3,944							4,343
	Total asset-backed securities	—			17,047			4,210							21,257
	Non-U.S. debt securities:
	Mortgage-backed securities	—			10,239			—							10,239
	Asset-backed securities	—			3,023			424							3,447
	Government securities	—			3,613			—							3,613
	Other	—			5,551			298							5,849
	Total non-U.S. debt securities	—			22,426			722							23,148
	State and political subdivisions	—			10,604			41							10,645
	Collateralized mortgage obligations	—			4,437			234							4,671
	Other U.S. debt securities	—			4,276			8							4,284
	U.S. equity securities	—			38			—							38
	Non-U.S. equity securities	—			2			—							2
	U.S. money-market mutual funds	—			532			—							532
	Non-U.S. money-market mutual funds	—			10			—							10
	Total investment securities available for sale	10,139			80,938			5,475							96,552
	Other assets:
	Derivative instruments:
	Foreign exchange contracts	—			16,797			68				$	(8,162	)	8,703
	Interest-rate contracts	—			63			—				(58		)	5
	Other derivative contracts	—			4			—				—			4
	Total derivative instruments	—			16,864			68				(8,220		)	8,712
	Other	115			—			—				—			115
	Total assets carried at fair value	$	10,822		$	98,267		$	5,543			$	(8,220	)	$	106,412
	Liabilities:
	Accrued expenses and other liabilities:
	Trading account liabilities:
	U.S. government securities	$	92		$	—		$	—			$	—		$	92
	Non-U.S. government securities	50			—			—				—			50
	Other	3			—			—				—			3
	Derivative instruments:
	Foreign exchange contracts	—			16,500			59				(9,911		)	$	6,648
	Interest-rate contracts	—			241			—				(49		)	192
	Other derivative contracts	—			64			9				—			73
	Total derivative instruments	—			16,805			68				(9,960		)	6,913
	Other	115			—			—				—			115
	Total liabilities carried at fair value	$	260		$	16,805		$	68			$	(9,960	)	$	7,173
	(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 $841 million and $2.58 billion, respectively, for cash collateral received from and provided to derivative counterparties.
		Fair-Value Measurements on a Recurring Basis
		as of December 31, 2013
	(In millions)	Quoted Market			Pricing Methods			Pricing Methods				Impact of Netting(1)			Total Net
Prices in Active			with Significant			with Significant			Carrying Value
Markets			Observable			Unobservable			in Consolidated
(Level 1)			Market Inputs			Market Inputs			Statement of
			(Level 2)			(Level 3)			Condition
Assets:
Trading account assets:
U.S. government securities	$	20		$	—		$	—						$	20
Non-U.S. government securities	399			—			—							399
Other	67			357			—							424
Total trading account assets	486			357			—							843
Investment securities available for sale:
U.S. Treasury and federal agencies:
Direct obligations	—			709			—							709
Mortgage-backed securities	—			22,847			716							23,563
Asset-backed securities:
Student loans	—			14,119			423							14,542
Credit cards	—			8,186			24							8,210
Sub-prime	—			1,203			—							1,203
Other	—			532			4,532							5,064
Total asset-backed securities	—			24,040			4,979							29,019
Non-U.S. debt securities:
Mortgage-backed securities	—			10,654			375							11,029
Asset-backed securities	—			4,592			798							5,390
Government securities	—			3,761			—							3,761
Other	—			4,263			464							4,727
Total non-U.S. debt securities	—			23,270			1,637							24,907
State and political subdivisions	—			10,220			43							10,263
Collateralized mortgage obligations	—			5,107			162							5,269
Other U.S. debt securities	—			4,972			8							4,980
U.S. equity securities	—			34			—							34
Non-U.S. equity securities	—			1			—							1
U.S. money-market mutual funds	—			422			—							422
Non-U.S. money-market mutual funds	—			7			—							7
Total investment securities available for sale	—			91,629			7,545							99,174
Other assets:
Derivatives instruments:
Foreign exchange contracts	—			11,892			19				$	(6,442	)	5,469
Interest-rate contracts	—			65			—				(59		)	6
Other derivative contracts	—			1			—				—			1
Total derivative instruments	—			11,958			19				(6,501		)	5,476
Other	97			—			—				—			97
Total assets carried at fair value	$	583		$	103,944		$	7,564			$	(6,501	)	$	105,590
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	—		$	11,454		$	17			$	(5,458	)	$	6,013
Interest-rate contracts	—			331			—				(94		)	237
Other derivative contracts	—			—			9				—			9
Total derivative instruments	—			11,785			26				(5,552		)	6,259
Other	97			—			—				—			97
Total liabilities carried at fair value	$	97		$	11,785		$	26			$	(5,552	)	$	6,356
(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 $1.93 billion and $979 million, respectively, for cash collateral received from and provided to derivative counterparties.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	'
	The following tables present activity related to our level-3 financial assets and liabilities during the three and nine months ended September 30, 2014 and 2013, respectively. Transfers into and out of level 3 are reported as of the beginning of the period presented. In the three and nine months ended September 30, 2014 and 2013, respectively, transfers out of level 3 were mainly related to certain mortgage- and asset-backed securities, 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
		Three Months Ended September 30, 2014
		Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
		June 30,			Unrealized Gains (Losses)																			into		out of			30-Sep-14		Unrealized
		2014																						Level 3		Level 3					Gains
																															(Losses)
																															Related to
																															Financial
																															Instruments
																															Held as of
																															September 30,
	(In millions)				Recorded			Recorded																							2014
					in			in Other
					Revenue			Comprehensive
								Income
	Assets:
	Investment securities available for sale:
	U.S. Treasury and federal agencies, mortgage-backed securities	$	96		$	—		$	—			$	168		$	—		$	—		$	(4	)	$	—	$	—		$	260
	Asset-backed securities:
	Student loans	322			—			(1		)		24			—			(74		)	(5		)	—		—			266
	Other	4,061			18			(8		)		275			—			—			(402		)	—		—			3,944
	Total asset-backed securities	4,383			18			(9		)		299			—			(74		)	(407		)	—		—			4,210
	Non-U.S. debt securities:
	Asset-backed securities	506			2			(1		)		—			—			—			(99		)	76		(60		)	424
	Other	515			—			—				—			—			—			(25		)	—		(192		)	298
	Total non-U.S. debt securities	1,021			2			(1		)		—			—			—			(124		)	76		(252		)	722
	State and political subdivisions	41			—			—				—			—			—			—			—		—			41
	Collateralized mortgage obligations	196			—			—				125			—			—			(7		)	—		(80		)	234
	Other U.S. debt securities	9			—			—				—			—			—			(1		)	—		—			8
	Total investment securities available for sale	5,746			20			(10		)		592			—			(74		)	(543		)	76		(332		)	5,475
	Other assets:
	Derivative instruments:
	Derivative instruments, Foreign exchange contracts	10			44			—				22			—			—			(8		)	—		—			68		$	40
	Total derivative instruments	10			44			—				22			—			—			(8		)	—		—			68		40
	Total assets carried at fair value	$	5,756		$	64		$	(10	)		$	614		$	—		$	(74	)	$	(551	)	$	76	$	(332	)	$	5,543	$	40
		Fair-Value Measurements Using Significant Unobservable Inputs
		Three Months Ended September 30, 2014
		Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
		June 30,			Unrealized (Gains) Losses																			into		out of			30-Sep-14		Unrealized
		2014																						Level 3		Level 3					(Gains)
																															Losses Related to
																															Financial
																															Instruments
																															Held as of
																															September 30,
	(In millions)				Recorded			Recorded																							2014
					in			in Other
					Revenue			Comprehensive
								Income
	Liabilities:
	Accrued expenses and other liabilities:
	Derivative instruments:
	Foreign exchange contracts	$	10		$	36		$	—			$	—		$	18		$	—		$	(5	)	$	—	$	—		$	59	$	35
	Other	9			—			—				—			—			—			—			—		—			9		—
	Total derivative instruments	19			36			—				—			18			—			(5		)	—		—			68		35
	Total liabilities carried at fair value	$	19		$	36		$	—			$	—		$	18		$	—		$	(5	)	$	—	$	—		$	68	$	35
		Fair-Value Measurements Using Significant Unobservable Inputs
		Nine Months Ended September 30, 2014
		Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
		December 31,			Unrealized Gains (Losses)																			into		out of			September 30,		Unrealized
		2013																						Level 3		Level 3			2014		Gains
																															(Losses)
																													Related to
																													Financial
																													Instruments
																													Held as of
																													September 30,
(In millions)				Recorded			Recorded																						2014
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies, mortgage-backed securities	$	716		$	—		$	—			$	168		$	—		$	—		$	(14	)	$	—	$	(610	)	$	260
Asset-backed securities:
Student loans	423			1			2				24			—			(74		)	(31		)	—		(79		)	266
Credit cards	24			—			—				—			—			—			(24		)	—		—			—
Other	4,532			46			(14		)		282			—			—			(902		)	—		—			3,944
Total asset-backed securities	4,979			47			(12		)		306			—			(74		)	(957		)	—		(79		)	4,210
Non-U.S. debt securities:
Mortgage-backed securities	375			—			—				—			—			—			—			—		(375		)	—
Asset-backed securities	798			5			—				—			—			—			(219		)	76		(236		)	424
Other	464			—			—				55			—			(1		)	(28		)	—		(192		)	298
Total non-U.S. debt securities	1,637			5			—				55			—			(1		)	(247		)	76		(803		)	722
State and political subdivisions	43			1			(1		)		—			—			—			(2		)	—		—			41
Collateralized mortgage obligations	162			—			1				205			—			(6		)	(20		)	—		(108		)	234
Other U.S. debt securities	8			—			—				—			—			—			—			—		—			8
Total investment securities available for sale	7,545			53			(12		)		734			—			(81		)	(1,240		)	76		(1,600		)	5,475
Other assets:
Derivative instruments:
Derivative instruments, Foreign exchange contracts	19			26			—				32			—			—			(9		)	—		—			68		$	35
Total derivative instruments	19			26			—				32			—			—			(9		)	—		—			68		35
Total assets carried at fair value	$	7,564		$	79		$	(12	)		$	766		$	—		$	(81	)	$	(1,249	)	$	76	$	(1,600	)	$	5,543	$	35
	Fair-Value Measurements Using Significant Unobservable Inputs
	Nine months ended September 30, 2014
	Fair Value  as of			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	December 31,			Unrealized (Gains) Losses																			into		out of			September 30,		Unrealized
	2013																						Level 3		Level 3			2014		(Gains)
																														Losses
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2014
				in			in Other
				Revenue			Comprehensive
							Income
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	17		$	22		$	—			$	—		$	28		$	—		$	(8	)	$	—	$	—		$	59	$	32
Other	9			—			—				—			—			—			—			—		—			9		—
Total derivative instruments	26			22			—				—			28			—			(8		)	—		—			68		32
Total liabilities carried at fair value	$	26		$	22		$	—			$	—		$	28		$	—		$	(8	)	$	—	$	—		$	68	$	32
	Fair Value Measurements Using Significant Unobservable Inputs
	Three Months Ended September 30, 2013
	Fair Value as of June 30,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	2013			Unrealized Gains (Losses)																			into		out of			30-Sep-13		Unrealized
																							Level 3		Level 3					Gains
																														(Losses)
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies, mortgage-backed securities	$	864		$	—		$	(1	)		$	—		$	—		$	—		$	(29	)	$	—	$	(93	)	$	741
Asset-backed securities:
Student loans	380			—			(2		)		—			—			—			(10		)	—		—			368
Credit cards	24			—			—				—			—			—			—			—		—			24
Other	3,848			13			(5		)		793			—			(24		)	(275		)	—		—			4,350
Total asset-backed securities	4,252			13			(7		)		793			—			(24		)	(285		)	—		—			4,742
Non-U.S. debt securities:
Mortgage-backed securities	328			—			(1		)		—			—			—			13			—		—			340
Asset-backed securities	756			1			1				164			—			—			(19		)	—		(104		)	799
Other	281			—			(1		)		149			—			—			12			—		—			441
Total non-U.S. debt securities	1,365			1			(1		)		313			—			—			6			—		(104		)	1,580
State and political subdivisions	45			—			(1		)		—			—			—			—			—		—			44
Collateralized mortgage obligations	238			—			(5		)		50			—			—			(11		)	15		(100		)	187
Other U.S. debt securities	9			—			—				—			—			—			—			—		—			9
Total investment securities available for sale	6,773			14			(15		)		1,156			—			(24		)	(319		)	15		(297		)	7,303
Other assets:
Derivative instruments:
Derivative instruments, Foreign exchange contracts	121			(21		)	—				7			—			—			(30		)	—		—			77		$	(16	)
Total derivative instruments	121			(21		)	—				7			—			—			(30		)	—		—			77		(16		)
Total assets carried at fair value	$	6,894		$	(7	)	$	(15	)		$	1,163		$	—		$	(24	)	$	(349	)	$	15	$	(297	)	$	7,380	$	(16	)
	Fair Value Measurements Using Significant Unobservable Inputs
	Three Months Ended September 30, 2013
	Fair Value as of June 30,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair		Change in
	2013			Unrealized (Gains) Losses																			into		out of			Value as of		Unrealized
																							Level 3		Level 3			September 30,		(Gains)
																												2013		Losses
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Liabilities:
Accrued expenses and other liabilities:
Derivative instruments:
Foreign exchange contracts	$	108		$	(17	)	$	—			$	—		$	5		$	—		$	(41	)	$	—	$	—		$	55	$	(15	)
Other	9			—			—				—			—			—			—			—		—			9		—
Total derivative instruments	117			(17		)	—				—			5			—			(41		)	—		—			64		(15		)
Total liabilities carried at fair value	$	117		$	(17	)	$	—			$	—		$	5		$	—		$	(41	)	$	—	$	—		$	64	$	(15	)
	Fair-Value Measurements Using Significant Unobservable Inputs
	Nine Months Ended September 30, 2013
	Fair Value  as of December 31,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
	2012			Unrealized Gains (Losses)																			into		out of			September 30,		Unrealized
																							Level 3		Level 3			2013		Gains
																														(Losses)
																														Related to
																														Financial
																														Instruments
																														Held as of
																														September 30,
(In millions)				Recorded			Recorded																							2013
				in			in Other
				Revenue			Comprehensive
							Income
Assets:
Investment securities available for sale:
U.S. Treasury and federal agencies:
Mortgage-backed securities	$	825		$	—		$	(1	)		$	92		$	—		$	—		$	(83	)	$	—	$	(92	)	$	741
Asset-backed securities:
Student loans	588			1			6				—			—			(26		)	(26		)	—		(175		)	368
Credit cards	67			—			—				—			—			—			(43		)	—		—			24
Other	3,994			40			25				1,358			—			(33		)	(1,034		)	—		—			4,350
Total asset-backed securities	4,649			41			31				1,358			—			(59		)	(1,103		)	—		(175		)	4,742
Non-U.S. debt securities:
Mortgage-backed securities	555			—			(1		)		—			—			—			(6		)	—		(208		)	340
Asset-backed securities	524			4			2				399			—			—			(88		)	139		(181		)	799
Other	140			—			—				328			—			—			13			—		(40		)	441
Total non-U.S. debt securities	1,219			4			1				727			—			—			(81		)	139		(429		)	1,580
State and political subdivisions	48			—			(1		)		—			—			—			(3		)	—		—			44
Collateralized mortgage obligations	117			1			(5		)		190			—			—			(31		)	15		(100		)	187
Other U.S. debt securities	9			—			—				—			—			—			—			—		—			9
Total investment securities available for sale	6,867			46			25				2,367			—			(59		)	(1,301		)	154		(796		)	7,303
Other assets:
Derivative instruments:
Foreign exchange contracts	113			119			—				25			—			—			(180		)	—		—			77		$	29
Total derivative instruments	113			119			—				25			—			—			(180		)	—		—			77		29
Total assets carried at fair value	$	6,980		$	165		$	25			$	2,392		$	—		$	(59	)	$	(1,481	)	$	154	$	(796	)	$	7,380	$	29
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	'
		Fair-Value Measurements Using Significant Unobservable Inputs
		Nine Months Ended September 30, 2013
		Fair Value  as of December 31,			Total Realized and							Purchases			Issuances			Sales			Settlements			Transfers		Transfers			Fair Value  as of		Change in
		2012			Unrealized (Gains) Losses																			into		out of			September 30,		Unrealized
																								Level 3		Level 3			2013		(Gains)
																															Losses
																															Related to
																															Financial
																															Instruments
																															Held as of
																															September 30,
	(In millions)				Recorded			Recorded																							2013
					in			in Other
					Revenue			Comprehensive
								Income
	Liabilities:
	Accrued expenses and other liabilities:
	Derivative instruments:
	Foreign exchange contracts	$	106		$	59		$	—			$	—		$	24		$	—		$	(134	)	$	—	$	—		$	55	$	15
	Other	9			—			—				—			—			—			—			—		—			9		—
	Total derivative instruments	115			59			—				—			24			—			(134		)	—		—			64		15
	Total liabilities carried at fair value	$	115		$	59		$	—			$	—		$	24		$	—		$	(134	)	$	—	$	—		$	64	$	15
Level 3 Total Realized And Unrealized Gains And Losses Recorded In Revenue	'
	The following table presents total realized and unrealized gains and losses for the periods indicated that were recorded in revenue for our level-3 financial assets and liabilities:
		Three Months Ended September 30,													Nine Months Ended September 30,
		Total Realized and						Change in							Total Realized and						Change in
		Unrealized Gains						Unrealized Gains							Unrealized Gains						Unrealized Gains
		(Losses) Recorded						(Losses) Related to							(Losses) Recorded						(Losses) Related to
		in Revenue						Financial							in Revenue						Financial
								Instruments Held at													Instruments Held at
								September 30,													September 30,
	(In millions)	2014			2013			2014				2013			2014			2013			2014			2013
	Fee revenue:
	Trading services	$	8		$	(4	)	$	5			$	(1	)	$	4		$	60		$	3		$	14
	Total fee revenue	8			(4		)	5				(1		)	4			60			3			14
	Net interest revenue	20			14			—				—			53			46			—			—
	Total revenue	$	28		$	10		$	5			$	(1	)	$	57		$	106		$	3		$	14
Fair Value Inputs, Assets and 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 September 30, 2014			As of December 31, 2013			Valuation Technique		Significant		As of September 30, 2014		As of December 31, 2013
											Unobservable Input
	Significant unobservable inputs readily available to State Street:
	Assets:
	Asset-backed securities, student loans		$	—		$	13		Discounted cash flows		Credit spread		—	%	3.5	%
	Asset-backed securities, credit cards		—			24			Discounted cash flows		Credit spread		—		2
	Asset-backed securities, other		66			92			Discounted cash flows		Credit spread		0.2		1.5
	State and political subdivisions		41			43			Discounted cash flows		Credit spread		1.6		1.7
	Derivative instruments, foreign exchange contracts		68			19			Option model		Volatility		7.7		11.4
	Total		$	175		$	191
	Liabilities:
	Derivative instruments, foreign exchange contracts		$	59		$	17		Option model		Volatility		7.7		11.2
	Derivative instruments, other(1)		9			9			Discounted cash flows		Participant redemptions		6		7.5
	Total		$	68		$	26
	(1) Relates to stable value wrap contracts; refer to the sensitivity discussion following the tables presented below, and to note 7.
Schedule of Availability of Significant Unobservable Inputs by Balance Sheet Classification	'
	The following tables present information with respect to the composition of our level-3 financial assets and
	liabilities, by availability of significant unobservable inputs, as of the dates indicated:
	30-Sep-14		Significant Unobservable Inputs Readily Available to State Street(1)			Significant Unobservable Inputs Not Developed by State Street and Not Readily Available(2)			Total Assets and Liabilities with Significant Unobservable Inputs
	(In millions)
	Assets:
	U.S. Treasury and federal agencies, mortgage-backed securities		$	—		$	260		$	260
	Asset-backed securities, student loans		—			266			266
	Asset-backed securities, other		66			3,878			3,944
	Non-U.S. debt securities, asset-backed securities		—			424			424
	Non-U.S. debt securities, other		—			298			298
	State and political subdivisions		41			—			41
	Collateralized mortgage obligations		—			234			234
	Other U.S. debt securities		—			8			8
	Derivative instruments, foreign exchange contracts		68			—			68
	Total		$	175		$	5,368		$	5,543
	Liabilities:
	Derivative instruments, foreign exchange contracts		$	59		$	—		$	59
	Derivative instruments, other		9			—			9
	Total		$	68		$	—		$	68
	(1) Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.
	(2) Fair value for these financial assets is measured using non-binding broker or dealer quotes.
	31-Dec-13		Significant Unobservable Inputs Readily Available to State Street(1)			Significant Unobservable Inputs Not Developed by State Street and Not Readily Available(2)			Total Assets and Liabilities with Significant Unobservable Inputs
	(In millions)
	Assets:
	U.S. Treasury and federal agencies, mortgage-backed securities		$	—		$	716		$	716
	Asset-backed securities, student loans		13			410			423
	Asset-backed securities, credit cards		24			—			24
	Asset-backed securities, other		92			4,440			4,532
	Non-U.S. debt securities, mortgage-backed securities		—			375			375
	Non-U.S. debt securities, asset-backed securities		—			798			798
	Non-U.S. debt securities, other		—			464			464
	State and political subdivisions		43			—			43
	Collateralized mortgage obligations		—			162			162
	Other U.S. debt securities		—			8			8
	Derivative instruments, foreign exchange contracts		19			—			19
	Total		$	191		$	7,373		$	7,564
	Liabilities:
	Derivative instruments, foreign exchange contracts		$	17		$	—		$	17
	Derivative instruments, other		9			—			9
	Total		$	26		$	—		$	26
	(1) Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.
	(2) Fair value for these financial assets is measured using non-binding broker or dealer quotes.
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 instruments defined by GAAP, excluding financial assets and liabilities 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
	30-Sep-14		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)
	(In millions)
	Financial Assets:
	Cash and due from banks		$	4,146		$	4,146		$	4,146			$	—		$	—
	Interest-bearing deposits with banks		86,946			86,946			—				86,946			—
	Securities purchased under resale agreements		2,603			2,603			—				2,603			—
	Investment securities held to maturity		18,767			18,865			—				18,865			—
	Net loans (excluding leases)		17,296			17,287			—				16,830			457
	Financial Liabilities:
	Deposits:
	Noninterest-bearing		$	66,134		$	66,134		$	—			$	66,134		$	—
	Interest-bearing - U.S.		24,435			24,435			—				24,435			—
	Interest-bearing - non-U.S.		117,399			117,399			—				117,399			—
	Securities sold under repurchase agreements		9,385			9,385			—				9,385			—
	Federal funds purchased		17			17			—				17			—
	Other short-term borrowings		4,307			4,307			—				4,307			—
	Long-term debt		9,016			9,352			—				8,474			878
									Fair-Value Hierarchy
	31-Dec-13		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)
	(In millions)
	Financial Assets:
	Cash and due from banks		$	3,220		$	3,220		$	3,220			$	—		$	—
	Interest-bearing deposits with banks		64,257			64,257			—				64,257			—
	Securities purchased under resale agreements		6,230			6,230			—				6,230			—
	Investment securities held to maturity		17,740			17,560			—				17,560			—
	Net loans (excluding leases)		12,363			12,355			—				11,908			447
	Financial Liabilities:
	Deposits:
	Noninterest-bearing		$	65,614		$	65,614		$	—			$	65,614		$	—
	Interest-bearing - U.S.		13,392			13,392			—				13,392			—
	Interest-bearing - non-U.S.		103,262			103,262			—				103,262			—
	Securities sold under repurchase agreements		7,953			7,953			—				7,953			—
	Federal funds purchased		19			19			—				19			—
	Other short-term borrowings		3,780			3,780			—				3,780			—
	Long-term debt		9,699			9,909			—				9,056			853

Investment_Securities_Tables

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Schedule of Marketable Securities	'
	The following table presents the amortized cost and fair value, and associated unrealized gains and losses, of investment securities as of the dates indicated:
		September 30, 2014										December 31, 2013
		Amortized			Gross					Fair		Amortized		Gross				Fair
		Cost			Unrealized					Value		Cost		Unrealized				Value
	(In millions)				Gains			Losses						Gains		Losses
	Available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	$	10,751		$	17		$	4	$	10,764	$	702	$	9	$	2	$	709
	Mortgage-backed securities	21,203			196			198		21,201		23,744		211		392		23,563
	Asset-backed securities:
	Student loans(1)	12,806			122			122		12,806		14,718		92		268		14,542
	Credit cards	3,128			13			30		3,111		8,230		21		41		8,210
	Sub-prime	1,054			2			59		997		1,291		3		91		1,203
	Other	4,239			114			10		4,343		4,949		138		23		5,064
	Total asset-backed securities	21,227			251			221		21,257		29,188		254		423		29,019
	Non-U.S. debt securities:
	Mortgage-backed securities	10,056			185			2		10,239		10,808		230		9		11,029
	Asset-backed securities	3,433			15			1		3,447		5,369		23		2		5,390
	Government securities	3,605			8			—		3,613		3,759		2		—		3,761
	Other	5,802			55			8		5,849		4,679		59		11		4,727
	Total non-U.S. debt securities	22,896			263			11		23,148		24,615		314		22		24,907
	State and political subdivisions	10,366			323			44		10,645		10,301		160		198		10,263
	Collateralized mortgage obligations	4,629			57			15		4,671		5,275		70		76		5,269
	Other U.S. debt securities	4,189			106			11		4,284		4,876		138		34		4,980
	U.S. equity securities	29			9			—		38		28		6		—		34
	Non-U.S. equity securities	2			—			—		2		1		—		—		1
	U.S. money-market mutual funds	532			—			—		532		422		—		—		422
	Non-U.S. money-market mutual funds	10			—			—		10		7		—		—		7
	Total	$	95,834		$	1,222		$	504	$	96,552	$	99,159	$	1,162	$	1,147	$	99,174
	Held to maturity:
	U.S. Treasury and federal agencies:
	Direct obligations	$	5,117		$	—		$	222	$	4,895	$	5,041	$	—	$	448	$	4,593
	Mortgage-backed securities	68			4			—		72		91		6		—		97
	Asset-backed securities:
	Student loans(1)	1,873			5			1		1,877		1,627		—		10		1,617
	Credit cards	897			2			—		899		762		1		—		763
	Other	633			3			1		635		782		1		2		781
	Total asset-backed securities	3,403			10			2		3,411		3,171		2		12		3,161
	Non-U.S. debt securities:
	Mortgage-backed securities	4,153			192			16		4,329		4,211		150		48		4,313
	Asset-backed securities	3,293			18			—		3,311		2,202		19		—		2,221
	Government securities	110			—			—		110		2		—		—		2
	Other	75			—			—		75		192		—		—		192
	Total non-U.S. debt securities	7,631			210			16		7,825		6,607		169		48		6,728
	State and political subdivisions	12			—			—		12		24		1		—		25
	Collateralized mortgage obligations	2,536			129			15		2,650		2,806		176		26		2,956
	Total	$	18,767		$	353		$	255	$	18,865	$	17,740	$	354	$	534	$	17,560
	(1) Substantially composed of securities guaranteed by the federal government with respect to at least 97% of defaulted principal and
	accrued interest on the underlying loans.
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
	September 30, 2014	Fair			Gross			Fair		Gross		Fair		Gross
		Value			Unrealized			Value		Unrealized		Value		Unrealized
	(In millions)				Losses					Losses				Losses
	Available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	$	4,374		$	3		$	158	$	1	$	4,532	$	4
	Mortgage-backed securities	3,391			23			7,026		175		10,417		198
	Asset-backed securities:
	Student loans	291			2			6,158		120		6,449		122
	Credit cards	—			—			1,258		30		1,258		30
	Sub-prime	—			—			936		59		936		59
	Other	606			2			506		8		1,112		10
	Total asset-backed securities	897			4			8,858		217		9,755		221
	Non-U.S. debt securities:
	Mortgage-backed securities	443			1			176		1		619		2
	Asset-backed securities	—			—			84		1		84		1
	Other	2,148			2			283		6		2,431		8
	Total non-U.S. debt securities	2,591			3			543		8		3,134		11
	State and political subdivisions	439			2			1,786		42		2,225		44
	Collateralized mortgage obligations	886			5			314		10		1,200		15
	Other U.S. debt securities	336			2			294		9		630		11
	Total	$	12,914		$	42		$	18,979	$	462	$	31,893	$	504
	Held to maturity:
	U.S. Treasury and federal agencies:
	Direct obligations	$	114		$	1		$	4,781	$	221	$	4,895	$	222
	Asset-backed securities:
	Student loans	364			1			—		—		364		1
	Other	79			1			—		—		79		1
	Total asset-backed securities	443			2			—		—		443		2
	Non-U.S. mortgage-backed securities
	Mortgage-backed securities	255			1			658		15		913		16
	Total non-U.S. debt securities	255			1			658		15		913		16
	Collateralized mortgage obligations	467			3			552		12		1,019		15
	Total	$	1,279		$	7		$	5,991	$	248	$	7,270	$	255
		Less than 12 months						12 months or longer				Total
	December 31, 2013	Fair			Gross			Fair		Gross		Fair		Gross
		Value			Unrealized			Value		Unrealized		Value		Unrealized
	(In millions)				Losses					Losses				Losses
	Available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	$	182		$	1		$	113	$	1	$	295	$	2
	Mortgage-backed securities	10,562			316			2,389		76		12,951		392
	Asset-backed securities:
	Student loans	1,930			16			7,252		252		9,182		268
	Credit cards	3,714			30			161		11		3,875		41
	Sub-prime	—			—			1,150		91		1,150		91
	Other	1,896			12			439		11		2,335		23
	Total asset-backed securities	7,540			58			9,002		365		16,542		423
	Non-U.S. debt securities:
	Mortgage-backed securities	868			2			258		7		1,126		9
	Asset-backed securities	551			1			16		1		567		2
	Other	1,655			9			150		2		1,805		11
	Total non-U.S. debt securities	3,074			12			424		10		3,498		22
	State and political subdivisions	3,242			113			1,268		85		4,510		198
	Collateralized mortgage obligations	1,581			55			510		21		2,091		76
	Other U.S. debt securities	1,039			25			58		9		1,097		34
	Total	$	27,220		$	580		$	13,764	$	567	$	40,984	$	1,147
	Held to maturity:
	U.S. Treasury and federal agencies:
	Direct obligations	$	4,571		$	448		$	—	$	—	$	4,571	$	448
	Asset-backed securities:
Student Loans	1,352			10			—		—		1,352		10
Other	297			1			29		1		326		2
Total asset-backed securities	1,649			11			29		1		1,678		12
Non-U.S. mortgage-backed securities	834			3			878		45		1,712		48
Collateralized mortgage obligations	759			18			161		8		920		26
Total	$	7,813		$	480		$	1,068	$	54	$	8,881	$	534
Investments Classified by Contractual Maturity Date	'
	The following table presents contractual maturities of debt investment securities as of September 30, 2014:
	(In millions)	Under 1			1 to 5			6 to 10		Over 10
		Year			Years			Years		Years
	Available for sale:
	U.S. Treasury and federal agencies:
	Direct obligations	$	151		$	6,766		$	3,300	$	547
	Mortgage-backed securities	183			2,441			4,753		13,824
	Asset-backed securities:
	Student loans	342			6,572			3,750		2,142
	Credit cards	307			1,513			1,291		—
	Sub-prime	9			14			—		974
	Other	255			1,069			1,149		1,870
	Total asset-backed securities	913			9,168			6,190		4,986
	Non-U.S. debt securities:
	Mortgage-backed securities	2,190			4,344			384		3,321
	Asset-backed securities	359			2,691			290		107
	Government securities	1,978			1,635			—		—
	Other	1,969			2,942			938		—
	Total non-U.S. debt securities	6,496			11,612			1,612		3,428
	State and political subdivisions	731			3,021			4,451		2,442
	Collateralized mortgage obligations	286			1,165			1,072		2,148
	Other U.S. debt securities	700			3,221			328		35
	Total	$	9,460		$	37,394		$	21,706	$	27,410
	Held to maturity:
	U.S. Treasury and federal agencies:
	Direct obligations	$	—		$	—		$	5,000	$	117
	Mortgage-backed securities	—			15			13		40
	Asset-backed securities
	Student loans	7			182			393		1,291
	Credit cards	—			375			522		—
	Other	19			401			208		5
	Total asset-backed securities	26			958			1,123		1,296
	Non-U.S. debt securities:
	Mortgage-backed securities	323			1,208			274		2,348
	Asset-backed securities	5			3,051			237		—
	Government securities	110			—			—		—
	Other	—			75			—		—
	Total non-U.S. debt securities	438			4,334			511		2,348
	State and political subdivisions	9			3			—		—
	Collateralized mortgage obligations	577			550			503		906
	Total	$	1,050		$	5,860		$	7,150	$	4,707
Gains and Losses Related to Investment Securities	'
	The following tables present gross realized gains and gross realized losses from sales of available-for-sale securities, and the components of net impairment losses included in net gains and losses related to investment securities, for the periods indicated:
		Three Months Ended September 30,
	(In millions)	2014			2013
	Gross realized gains from sales of available-for-sale securities	$	48		$	11
	Gross realized losses from sales of available-for-sale securities	(48		)	(5		)
	Net impairment losses:
	Gross losses from other-than-temporary impairment	—			(13		)
	Losses reclassified (from) to other comprehensive income	—			3
	Net impairment losses(1)	—			(10		)
	Gains related to investment securities, net	$	—		$	(4	)
	(1) Net impairment losses, recognized in our consolidated statement of income, were composed of the following:
	Impairment associated with expected credit losses	$	—		$	(8	)
	Impairment associated with management's intent to sell impaired securities prior to recovery in value	—			—
	Impairment associated with adverse changes in timing of expected future cash flows	—			(2		)
	Net impairment losses	$	—		$	(10	)
		Nine Months Ended September 30,
	(In millions)	2014			2013
	Gross realized gains from sales of available-for-sale securities	$	64		$	98
	Gross realized losses from sales of available-for-sale securities	(49		)	(87		)
	Net impairment losses:
	Gross losses from other-than-temporary impairment	(1		)	(19		)
	Losses reclassified (from) to other comprehensive income	(10		)	(1		)
	Net impairment losses(1)	(11		)	(20		)
	Gains related to investment securities, net	$	4		$	(9	)
	(1) Net impairment losses, recognized in our consolidated statement of income, were composed of the following:
	Impairment associated with expected credit losses	$	(10	)	$	(8	)
	Impairment associated with management's intent to sell impaired securities prior to recovery in value	—			(6		)
	Impairment associated with adverse changes in timing of expected future cash flows	(1		)	(6		)
	Net impairment losses	$	(11	)	$	(20	)
Schedule of Credit-Related Loss Activity Recognized in Earnings	'
	The following table presents activity with respect to net impairment losses for the periods indicated:
		Nine Months Ended September 30,
	(In millions)	2014			2013
	Beginning balance	$	122		$	124
	Plus losses for which other-than-temporary impairment was not previously recognized	—			14
	Plus losses for which other-than-temporary impairment was previously recognized	11			6
	Less previously recognized losses related to securities sold or matured	(11		)	(10		)
	Less losses related to securities intended or required to be sold	(6		)	—
	Ending balance	$	116		$	134

Loans_and_Leases_Tables

Loans and Leases (Tables)	9 Months Ended
	Sep. 30, 2014
Loans and Leases Receivable Disclosure [Abstract]	'
Net Loans	'
	The following table presents our recorded investment in loans and leases, by segment and class, as of the dates indicated:
	(In millions)	September 30, 2014			December 31, 2013
	Institutional:
	Investment funds:
	U.S.	$	10,896		$	8,695
	Non-U.S.	3,250			1,718
	Commercial and financial:
	U.S.	2,506			1,372
	Non-U.S.	240			154
	Purchased receivables:
	U.S.	142			217
	Non-U.S.	—			26
	Lease financing:
	U.S.	340			339
	Non-U.S.	728			756
	Total institutional	18,102			13,277
	Commercial real estate:
	U.S.	296			209
	Total loans and leases	18,398			13,486
	Allowance for loan losses	(34		)	(28		)
	Loans and leases, net of allowance for loan losses	$	18,364		$	13,458
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:
		Institutional										Commercial Real Estate
	September 30, 2014	Investment			Commercial and Financial			Purchased		Lease		Property Development		Other		Total
		Funds						Receivables		Financing						Loans and
	(In millions)															Leases
	Investment grade(1)	$	13,864		$	916		$	142	$	1,034	$	—	$	28	$	15,984
	Speculative(2)	282			1,830			—		34		268		—		2,414
	Total	$	14,146		$	2,746		$	142	$	1,068	$	268	$	28	$	18,398
		Institutional										Commercial Real Estate
	December 31, 2013	Investment			Commercial and Financial			Purchased		Lease		Property Development		Other		Total
		Funds						Receivables		Financing						Loans and
	(In millions)															Leases
	Investment grade(1)	$	10,282		$	740		$	243	$	1,068	$	—	$	29	$	12,362
	Speculative(2)	131			770			—		27		180		—		1,108
	Special mention(3)	—			16			—		—		—		—		16
	Total	$	10,413		$	1,526		$	243	$	1,095	$	180	$	29	$	13,486
	(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.
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:
		September 30, 2014								December 31, 2013
	(In millions)	Institutional			Commercial Real Estate			Total Loans and Leases		Institutional		Commercial Real Estate		Total Loans and Leases
	Loans and leases:
	Individually evaluated for impairment	$	—		$	130		$	130	$	26	$	180	$	206
	Collectively evaluated for impairment(1)	18,102			166			18,268		13,251		29		13,280
	Total	$	18,102		$	296		$	18,398	$	13,277	$	209	$	13,486
	(1) As of September 30, 2014 and December 31, 2013, all of the allowance for loan losses of $34 million and $28 million, respectively, related to institutional loans collectively evaluated for impairment.
Impaired Loans	'
	The following tables present information related to our recorded investment in impaired loans and leases as of the dates, or for the periods, indicated:
		September 30, 2014								December 31, 2013
	(In millions)	Recorded Investment			Unpaid			Related Allowance(1)		Recorded Investment		Unpaid		Related Allowance(1)
					Principal							Principal
					Balance							Balance
	With no related allowance recorded:
	CRE—property development	$	130		$	143		$	—	$	130	$	143	$	—
	CRE—property development—acquired credit-impaired	—			34			—		—		34		—
	CRE—other—acquired credit-impaired	—			22			—		—		21		—
	Total CRE	$	130		$	199		$	—	$	130	$	198	$	—
	(1) As of September 30, 2014 and December 31, 2013, all of the allowance for loan losses of $34 million and $28 million, respectively, related to loans that were not impaired.
		Three Months Ended September 30,
		Average Recorded Investment						Interest Revenue Recognized
		2014			2013			2014		2013
	(In millions)
	With no related allowance recorded:
	CRE—property development	$	130		$	130		$	3	$	2
	Total CRE	$	130		$	130		$	3	$	2
		Nine Months Ended September 30,
		Average Recorded Investment						Interest Revenue Recognized
		2014			2013			2014		2013
	(In millions)
	With no related allowance recorded:
	CRE—property development	$	130		$	160		$	8	$	17
	Total CRE	$	130		$	160		$	8	$	17
	As of both September 30, 2014 and December 31, 2013, we held an aggregate of approximately $130 million of CRE loans, presented in the preceding impaired loans and leases table, which were modified in troubled debt restructurings.
Schedule of Activity in the Allowance for Loan Losses	'
	The following tables present activity in the allowance for loan losses for the periods indicated:
		Three Months Ended September 30,
		2014								2013
	(In millions)	Institutional			Commercial			Total Loans and Leases		Institutional		Commercial		Total Loans and Leases
					Real Estate							Real Estate
	Allowance for loan losses(1):
	Beginning balance	$	32		$	—		$	32	$	22	$	—	$	22
	Charge-offs	—			—			—		—		—		—
	Provisions	2			—			2		—		—		—
	Recoveries	—			—			—		—		—		—
	Ending balance	$	34		$	—		$	34	$	22	$	—	$	22
		Nine Months Ended September 30,
		2014								2013
	(In millions)	Institutional			Commercial			Total Loans and Leases		Institutional		Commercial		Total Loans and Leases
					Real Estate							Real Estate
	Allowance for loan losses(1):
	Beginning balance	$	28		$	—		$	28	$	22	$	—	$	22
	Charge-offs	—			—			—		—		—		—
	Provisions	6			—			6		—		—		—
	Recoveries	—			—			—		—		—		—
	Ending balance	$	34		$	—		$	34	$	22	$	—	$	22
	(1) As of September 30, 2014, approximately $22 million of our allowance for loan losses was related to senior secured bank loans included in the institutional segment; the remaining $12 million was related to other commercial-and-financial loans in the institutional segment.

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2014
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:
		Nine Months Ended September 30,
		2014									2013
	(In millions)	Investment			Investment			Total			Investment			Investment			Total
		Servicing			Management						Servicing			Management
	Goodwill:
	Beginning balance	$	5,999		$	37		$	6,036		$	5,941		$	36		$	5,977
	Foreign currency translation and other, net	(134		)	(3		)	(137		)	28			1			29
	Ending balance	$	5,865		$	34		$	5,899		$	5,969		$	37		$	6,006
Changes In The Carrying Amount Of Other Intangible Assets	'
	The following table presents changes in the net carrying amount of other intangible assets during the periods indicated:
		Nine Months Ended September 30,
		2014									2013
	(In millions)	Investment			Investment			Total			Investment			Investment			Total
		Servicing			Management						Servicing			Management
	Other intangible assets:
	Beginning balance	$	2,321		$	39		$	2,360		$	2,492		$	47		$	2,539
	Amortization	(155		)	(7		)	(162		)	(153		)	(7		)	(160		)
	Foreign currency translation and other, net	(75		)	(2		)	(77		)	17			—			17
	Ending balance	$	2,091		$	30		$	2,121		$	2,356		$	40		$	2,396
Schedule of Finite-Lived Intangible Assets	'
	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:
		September 30, 2014									December 31, 2013
	(In millions)	Gross			Accumulated			Net			Gross			Accumulated			Net
		Carrying			Amortization			Carrying			Carrying			Amortization			Carrying
		Amount						Amount			Amount						Amount
	Client relationships	$	2,614		$	(1,060	)	$	1,554		$	2,706		$	(975	)	$	1,731
	Core deposits	697			(213		)	484			717			(191		)	526
	Other	220			(137		)	83			234			(131		)	103
	Total	$	3,531		$	(1,410	)	$	2,121		$	3,657		$	(1,297	)	$	2,360

Other_Assets_Tables

Other Assets (Tables)	9 Months Ended
	Sep. 30, 2014
Other Assets [Abstract]	'
Components of Other Assets	'
	The following table presents the components of other assets as of the dates indicated:
	(In millions)	September 30, 2014		December 31, 2013
	Collateral deposits, net	$	17,540	$	13,706
	Unrealized gains on derivative financial instruments, net	8,712		5,476
	Bank-owned life insurance	2,391		2,343
	Investments in joint ventures and other unconsolidated entities	1,741		1,644
	Receivable for securities sold	917		—
	Accounts receivable	843		950
	Receivable for securities settlement	396		195
	Prepaid expenses	307		286
	Income taxes receivable	258		337
	Deferred tax assets, net of valuation allowance	253		263
	Deposits with clearing organizations	231		177
	Other(1)	556		613
	Total	$	34,145	$	25,990
	(1)	Included other real estate owned of approximately $61 million and $59 million as of September 30, 2014 and December 31, 2013, respectively.

Contingencies_Tables

Contingencies (Tables)	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Total Worldwide Revenue from Foreign Exchanges	'
	The following table summarizes our estimated total revenue worldwide from indirect foreign exchange trading for the periods indicated:
	(In millions)	Revenue from indirect foreign exchange trading
	2008	$	462
	2009	369
	2010	336
	2011	331
	2012	248
	2013	285
	Nine Months Ended September 30, 2014	186

Commitments_and_Guarantees_Tab

Commitments and Guarantees (Tables)	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Guarantor Obligations	'
	The following table presents the aggregate gross contractual amounts of our off-balance sheet guarantees as of the dates indicated. Amounts presented do not reflect participations to independent third parties.
	(In millions)	September 30, 2014		December 31, 2013
	Indemnified securities financing	$	340,239	$	320,078
	Stable value protection	24,305		24,906
	Asset purchase agreements	4,205		4,685
	Standby letters of credit	4,455		4,612
Schedule of Repurchase Agreements	'
	The following table summarizes the 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)	September 30, 2014		December 31, 2013
	Aggregate fair value of indemnified securities financing	$	340,239	$	320,078
	Aggregate fair value of cash and securities held by us, as agent, as collateral for indemnified securities financing	354,516		331,732
	Aggregate fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements	81,870		85,374
	Aggregate fair value of cash and securities held by us or our agents as collateral for investments in indemnified repurchase agreements	87,191		91,097

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	The following table presents the after-tax components of AOCI as of the dates indicated:
	(In millions)	September 30, 2014			December 31, 2013
	Net unrealized gains on cash flow hedges	$	217		$	161
	Net unrealized gains (losses) on available-for-sale securities portfolio	254			(56		)
	Net unrealized gains (losses) related to reclassified available-for-sale securities	46			(72		)
	Net unrealized gains (losses) on available-for-sale securities	300			(128		)
	Net unrealized losses on available-for-sale securities designated in fair value hedges	(106		)	(97		)
	Other-than-temporary impairment on available-for-sale securities related to factors other than credit	1			4
	Net unrealized losses on hedges of net investments in non-U.S. subsidiaries	(14		)	(14		)
	Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	(31		)	(47		)
	Net unrealized losses on retirement plans	(185		)	(203		)
	Foreign currency translation	(289		)	229
	Total	$	(107	)	$	(95	)
	The following tables present changes in AOCI by component, net of related taxes, for the periods indicated:
		Nine Months Ended September 30, 2014
	(In millions)	Net Unrealized Gains (Losses) on Cash Flow Hedges			Net Unrealized Gains (Losses) on Available-for-Sale Securities			Net Unrealized 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
	Beginning balance	$	161		$	(221	)	$	(14	)	$	(47	)	$	(203	)	$	229		$	(95	)
	Other comprehensive income (loss) before reclassifications	54			425			—			15			(1		)	(518		)	(25		)
	Amounts reclassified out of AOCI	2			(9		)	—			1			19			—			13
	Other comprehensive income (loss)	56			416			—			16			18			(518		)	(12		)
	Ending balance	$	217		$	195		$	(14	)	$	(31	)	$	(185	)	$	(289	)	$	(107	)
		Nine Months Ended September 30, 2013
	(In millions)	Net Unrealized Gains (Losses) on Cash Flow Hedges			Net Unrealized Gains (Losses) on Available-for-Sale Securities			Net Unrealized 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
	Beginning balance	$	69		$	519		$	(14	)	$	(65	)	$	(283	)	$	134		$	360
	Other comprehensive income (loss) before reclassifications	59			(578		)	—			11			(6		)	22			(492		)
	Amounts reclassified out of AOCI	2			(3		)	—			3			15			1			18
	Other comprehensive income (loss)	61			(581		)	—			14			9			23			(474		)
	Ending balance	$	130		$	(62	)	$	(14	)	$	(51	)	$	(274	)	$	157		$	(114	)
Schedule of Reclassifications Out of AOCI	'
		Three Months Ended September 30,
		2014			2013
	(In millions)	Amounts Reclassified out of AOCI						Affected Line Item in Consolidated Statement of Income
	Cash flow hedges:
	Interest-rate contracts	$	1		$	—		Net interest revenue
	Available-for-sale securities:
	Net realized gains from sales of available-for-sale securities, net of related taxes of ($2)	—			(4		)	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 tax benefits of $1	—			1			Losses reclassified (from) to other comprehensive income
	Retirement plans:
	Amortization of actuarial losses, net of related tax benefits of $3 and $3, respectively	2			5			Compensation and employee benefits expenses
	Total reclassifications out of AOCI	$	3		$	2
		Nine Months Ended September 30,
		2014			2013
	(In millions)	Amounts Reclassified out of AOCI						Affected Line Item in Consolidated Statement of Income
	Cash flow hedges:
	Interest-rate contracts, net of related tax benefit of $1 and $1, respectively	$	2		$	2		Net interest revenue
	Available-for-sale securities:
	Net realized gains from sales of available-for-sale securities, net of related taxes of ($6) and ($4), respectively	(9		)	(7		)	Net gains (losses) from sales of available-for-sale securities
	Other-than-temporary impairment on available-for-sale securities related to factors other than credit, net of related tax benefit of $2	—			4			Losses reclassified (from) to other comprehensive income
	Held-to-maturity securities:
	Other-than-temporary impairment on held-to-maturity securities related to factors other than credit, net of related tax benefit of $3 for 2013	1			3			Losses reclassified (from) to other comprehensive income
	Retirement plans:
	Amortization of actuarial losses, net of related taxes of ($2) and tax benefits of $9, respectively	19			15			Compensation and employee benefits expenses
	Foreign currency translation:
	Sales of non-U.S. entities, net of related taxes of ($1)	—			1			Processing fees and other revenue
	Total reclassifications out of AOCI	$	13		$	18

Regulatory_Capital_Tables

Regulatory Capital (Tables)	9 Months Ended
	Sep. 30, 2014
Banking and Thrift [Abstract]	'
Schedule of Regulatory Capital	'
	The following table presents the regulatory capital structure, total risk-weighted assets and related 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
	(Dollars in millions)					Basel III Advanced Approach September 30, 2014(1)			Basel III Transitional September 30, 2014(2)			December 31, 2013(3)			Basel III Advanced Approach September 30, 2014(1)			Basel III Transitional September 30, 2014(2)			December 31, 2013(3)
	Common shareholders' equity:
	Common stock and related surplus					$	10,284		$	10,284		$	10,280		$	10,840		$	10,840		$	10,786
	Retained earnings					14,531			14,531			13,395			9,500			9,500			9,064
	Accumulated other comprehensive income (loss)					(264		)	(264		)	215			(220		)	(220		)	209
	Treasury stock, at cost					(4,785		)	(4,785		)	(3,693		)	—			—			—
	Total					19,766			19,766			20,197			20,120			20,120			20,059
	Regulatory capital adjustments:
	Goodwill and other intangible assets, net of associated deferred tax liabilities(4)					(5,942		)	(5,942		)	(7,743		)	(5,672		)	(5,672		)	(7,341		)
	Other adjustments					(43		)	(43		)	—			(132		)	(132		)	—
	Tier 1 common capital					13,781			13,781			12,454			14,316			14,316			12,718
	Preferred stock					1,233			1,233			491			—			—			—
	Trust preferred capital securities subject to phase-out from tier 1 capital					475			475			950			—			—			—
	Other adjustments					(171		)	(171		)	—			—			—			—
	Tier 1 capital					15,318			15,318			13,895			14,316			14,316			12,718
	Qualifying subordinated long-term debt					1,738			1,738			1,918			1,754			1,754			1,936
	Trust preferred capital securities phased out of tier 1 capital					475			475			NA			—			—			NA
	Other adjustments					3			3			(26		)	—			—			45
	Total capital					$	17,534		$	17,534		$	15,787		$	16,070		$	16,070		$	14,699
	Risk-weighted assets:
	Credit risk					$	67,915		$	90,377		$	78,864		$	60,610		$	87,150		$	76,197
	Operational risk					35,960			NA			NA			35,530			NA			NA
	Market risk					4,203			1,423			1,262			3,707			1,423			1,262
	Total risk-weighted assets					$	108,078		$	91,800		$	80,126		$	99,847		$	88,573		$	77,459
	Adjusted quarterly average assets					$	240,529		$	240,529		$	202,801		$	236,340		$	236,340		$	199,301
	Capital Ratios:	Minimum Requirements(5) 2014		Minimum Requirements(6) 2013
	Tier 1 common risk-based capital	4	%	NA		12.8		%	15		%	15.5		%	14.3		%	16.2		%	16.4		%
	Tier 1 risk-based capital	5.5		4	%	14.2			16.7			17.3			14.3			16.2			16.4
	Total risk-based capital	8		8		16.2			19.1			19.7			16.1			18.1			19
	Tier 1 leverage	4		4		6.4			6.4			6.9			6.1			6.1			6.4
	NA: Not applicable.
	(1) Tier 1 common capital, tier 1 capital and total capital ratios as of September 30, 2014 were calculated in conformity with the advanced approaches provisions of the Basel III final rule. Tier 1 leverage ratio as of September 30, 2014 was calculated in conformity with the Basel III final rule.
	(2) Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of September 30, 2014 were calculated in conformity with the transitional provisions of the Basel III final rule. Specifically, these ratios reflect tier 1 common, tier 1 and total capital (the numerator) calculated in conformity with the provisions of the Basel III final rule, and total risk-weighted assets or, with respect to the tier 1 leverage ratio, quarterly average assets (in both cases, the denominator), calculated in conformity with the provisions of Basel I.
	(3) Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of December 31, 2013 were calculated in conformity with the provisions of Basel I.
	(4) Amounts for State Street and State Street Bank as of September 30, 2014 consisted of goodwill, net of associated deferred tax liabilities, and 20% of other intangible assets, net of associated deferred tax liabilities, the latter phased in as a deduction from capital, in conformity with the Basel III final rule.
	(5) Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of September 30, 2014.
	(6) Minimum requirements listed, governed by Basel I, are as of December 31, 2013.

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
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)	September 30,				December 31,
		2014				2013
	Derivatives not designated as hedging instruments:
	Interest-rate contracts:
	Swap agreements and forwards	$	842			$	1,023
	Options and caps purchased	9				27
	Options and caps written	9				27
	Futures	6,389				3,282
	Foreign exchange contracts:
	Forward, swap and spot	1,307,605				1,124,355
	Options purchased	2,923				1,666
	Options written	2,399				1,423
	Futures	19				—
	Credit derivative contracts:
	Credit swap agreements	192				141
	Total return swap agreements(1)	8				—
	Commodity and equity contracts:
	Commodity(1)	555				2
	Equity(1)	86				1
	Other:
	Stable value contracts	24,305				24,906
	Deferred cash awards(2)	227				42
	Derivatives designated as hedging instruments:
	Interest-rate contracts:
	Swap agreements	5,212				5,221
	Foreign exchange contracts:
	Forward and swap	2,693				2,783
	(1) Primarily composed of positions held by a consolidated sponsored investment fund, more fully described in note 9.
	(2) Represents grants of deferred cash awards to employees; refer to discussion in this note under "Derivatives Not Designated as Hedging Instruments."
Notional Amount of Interest Rate Swap Agreements Designated as Fair Value and Cash Flow Hedges	'
	The following table presents the aggregate notional amounts of these interest-rate contracts and the related assets or liabilities being hedged as of the dates indicated:
		September 30, 2014
	(In millions)	Fair				Cash				Total
		Value				Flow
		Hedges				Hedges
	Investment securities available for sale	$	2,583			$	129			$	2,712
	Long-term debt(1)	2,500				—				2,500
	Total	$	5,083			$	129			$	5,212
		December 31, 2013
	(In millions)	Fair				Cash				Total
		Value				Flow
		Hedges				Hedges
	Investment securities available for sale	$	2,589			$	132			$	2,721
	Long-term debt(1)	2,500				—				2,500
	Total	$	5,089			$	132			$	5,221
	(1) As of September 30, 2014, these fair value hedges increased the carrying value of long-term debt presented in our consolidated statement of condition by $25 million. As of December 31, 2013, these fair value hedges decreased the carrying value of long-term debt presented in our consolidated statement of condition by $35 million.
Contractual and Weighted-Average Interest Rates, Which Include the Effects of Hedges Related to Financial Instruments	'
	The following tables present 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:
		Three Months Ended September 30,
		2014						2013
		Contractual			Rate Including			Contractual			Rate Including
		Rates			Impact of Hedges			Rates			Impact of Hedges
	Long-term debt	3.44	%		2.64	%		3.34	%		2.67	%
		Nine Months Ended September 30,
		2014						2013
		Contractual			Rate Including			Contractual			Rate Including
		Rates			Impact of Hedges			Rates			Impact of Hedges
	Long-term debt	3.45	%		2.66	%		3.49	%		2.77	%
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 disclosed in note 2.
		Derivatives - Assets
		Balance Sheet		Fair Value
		Location
	(In millions)			September 30, 2014				December 31, 2013
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts	Other assets		$	16,434			$	11,552
	Interest-rate contracts	Other assets		16				29
	Other derivative contracts	Other assets		4				1
	Total			$	16,454			$	11,582
	Derivatives designated as hedging instruments:
	Foreign exchange contracts	Other assets		$	431			$	359
	Interest-rate contracts	Other assets		47				36
	Total			$	478			$	395
		Derivatives - Liabilities
		Balance Sheet		Fair Value
		Location
	(In millions)			September 30, 2014				December 31, 2013
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts	Other liabilities		$	16,556			$	11,428
	Other derivative contracts	Other liabilities		73				23
	Interest-rate contracts	Other liabilities		16				29
	Total			$	16,645			$	11,480
	Derivatives designated as hedging instruments:
	Interest-rate contracts	Other liabilities		$	225			$	302
	Foreign exchange contracts	Other liabilities		3				43
	Total			$	228			$	345
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		Amount of Gain (Loss) on Derivative Recognized
		Derivative in Consolidated		in Consolidated Statement of Income
		Statement of Income
				Three Months Ended September 30,								Nine Months Ended September 30,
	(In millions)			2014				2013				2014			2013
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts	Trading services revenue		$	163			$	147			$	441		$	461
	Interest-rate contracts	Trading services revenue		1				—				—			3
	Credit derivative contracts	Processing fees and other revenue		—				1				(1		)	1
	Other derivative contracts	Trading services revenue		1				—				1			—
	Total			$	165			$	148			$	441		$	465
		Location of (Gain) Loss on		Amount of (Gain) Loss on Derivative Recognized
		Derivative in Consolidated		in Consolidated Statement of Income
		Statement of Income
				Three Months Ended September 30,								Nine Months Ended September 30,
	(In millions)			2014				2013				2014			2013
	Derivatives not designated as hedging instruments:
	Other derivative contracts	Compensation and employee benefits		$	18			$	4			$	89		$	10
	Total			$	18			$	4			$	89		$	10
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								Hedged Item in Fair Value Hedging Relationship		Location of Gain (Loss) on Hedged Item in Consolidated Statement of Income	Amount of Gain
				(Loss) on Derivative											(Loss) on Hedged
				Recognized in											Item Recognized in
				Consolidated											Consolidated
				Statement of Income											Statement of Income
	(In millions)			Three Months Ended September 30, 2014				Nine Months Ended September 30, 2014							Three Months Ended September 30, 2014			Nine Months Ended September 30, 2014
	Derivatives designated as fair value hedges:
	Foreign exchange contracts	Processing fees and		$	(82	)		$	(22	)		Investment securities		Processing fees and	$	82		$	22
		other revenue												other revenue
	Interest-rate contracts	Processing fees and		24				(17		)		Available-for-sale securities		Processing fees and	(23		)	15
		other revenue												other revenue(1)
	Interest-rate contracts	Processing fees and		(8		)		88				Long-term debt		Processing fees and	9			(80		)
		other revenue												other revenue
	Total			$	(66	)		$	49						$	68		$	(43	)
		Location of Gain (Loss) on Derivative in Consolidated Statement of Income		Amount of Gain								Hedged Item in Fair Value Hedging Relationship		Location of Gain (Loss) on Hedged Item in Consolidated Statement of Income	Amount of Gain
				(Loss) on Derivative											(Loss) on Hedged
				Recognized in											Item Recognized in
				Consolidated											Consolidated
				Statement of Income											Statement of Income
	(In millions)			Three Months Ended September 30, 2013				Nine Months Ended September 30, 2013							Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013
	Derivatives designated as fair value hedges:
	Foreign exchange contracts	Processing fees and		$	20			$	(135	)		Investment securities		Processing fees and	$	(20	)	$	135
		other revenue												other revenue
	Interest-rate contracts	Processing fees and		(14		)		(146		)		Long-term debt		Processing fees and	12			133
		other revenue												other revenue
	Interest-rate contracts	Processing fees and		(6		)		15				Available-for-sale securities		Processing fees and	7			(15		)
		other revenue												other revenue(1)
	Total			$	—			$	(266	)					$	(1	)	$	253
	(1) Represents amounts reclassified out of other comprehensive income, or OCI. For the three and nine months ended September 30, 2014, $14 million of unrealized gains and $9 million of unrealized losses, respectively, on available-for-sale securities designated in fair value hedges were recognized in OCI. For the three and nine months ended September 30, 2013, $1 million and $61 million, respectively, of unrealized gains on available-for-sale 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 net interest revenue, represent hedge ineffectiveness.
		Amount of Gain								Location of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income		Amount of Gain						Location of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		Amount of Gain
		(Loss) on Derivative										(Loss) Reclassified								(Loss) on Derivative
		Recognized in Other										from OCI to								Recognized in
		Comprehensive										Consolidated								Consolidated
		Income										Statement of Income								Statement of Income
		Three Months Ended September 30, 2014				Nine Months Ended September 30, 2014						Three Months Ended September 30, 2014			Nine Months Ended September 30, 2014					Three Months Ended September 30, 2014		Nine Months Ended September 30, 2014
	(In millions)
	Derivatives designated as cash flow hedges:
	Interest-rate contracts	$	(1	)		$	(3	)		Net interest revenue		$	(1	)	$	(3	)	Net interest revenue		$	1	$	3
	Foreign exchange contracts	92				28				Net interest revenue		—			—			Net interest revenue		2		4
	Total	$	91			$	25					$	(1	)	$	(3	)			$	3	$	7
		Amount of Gain								Location of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income		Amount of Gain						Location of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		Amount of Gain
		(Loss) on Derivative										(Loss) Reclassified								(Loss) on Derivative
		Recognized in Other										from OCI to								Recognized in
		Comprehensive										Consolidated								Consolidated
		Income										Statement of Income								Statement of Income
		Three Months Ended September 30, 2013				Nine Months Ended September 30, 2013						Three Months Ended September 30, 2013			Nine Months Ended September 30, 2013					Three Months Ended September 30, 2013		Nine Months Ended September 30, 2013
	(In millions)
	Derivatives designated as cash flow hedges:
	Interest-rate contracts	$	(1	)		$	10			Net interest revenue		$	(1	)	$	(3	)	Net interest revenue		$	1	$	3
	Foreign exchange contracts	(55		)		98				Net interest revenue		—			—			Net interest revenue		—		5
	Total	$	(56	)		$	108					$	(1	)	$	(3	)			$	1	$	8

Offsetting_Arrangements_Tables

Offsetting Arrangements (Tables)	9 Months Ended
	Sep. 30, 2014
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:	30-Sep-14								31-Dec-13
	(In millions)	Gross Amounts of Recognized Assets(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Assets Presented in Statement of Condition			Gross Amounts of Recognized Assets(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Assets Presented in Statement of Condition
	Derivatives:
	Foreign exchange contracts	$	16,865	$	(7,345	)	$	9,520		$	11,911	$	(4,514	)	$	7,397
	Interest-rate contracts	63		(34		)	29			65		(59		)	6
	Other derivative contracts	4		—			4			1		—			1
	Cash collateral netting	—		(841		)	(841		)	—		(1,928		)	(1,928		)
	Total derivatives	$	16,932	$	(8,220	)	$	8,712		$	11,977	$	(6,501	)	$	5,476
	Other financial instruments:
	Resale agreements and securities borrowing(3)	$	48,078	$	(29,692	)	$	18,386		$	48,221	$	(30,700	)	$	17,521
	Total derivatives and other financial instruments	$	65,010	$	(37,912	)	$	27,098		$	60,198	$	(37,201	)	$	22,997
	(1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
	(2) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(3) Included in the $18,386 million as of September 30, 2014 were $2,603 million of resale agreements and $15,783 million of collateral provided related to securities borrowing. Included in the $17,521 million as of December 31, 2013 were $6,230 million of resale agreements and $11,291 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 7 for additional information with respect to principal securities finance transactions.
		30-Sep-14										31-Dec-13
				Gross Amounts Not Offset in Statement of Condition(1)											Gross Amounts Not Offset in Statement of Condition(1)
	(In millions)	Net Amount of Assets Presented in Statement of Condition		Counterparty Netting			Collateral Received			Net Amount(2)		Net Amount of Assets Presented in Statement of Condition			Counterparty Netting			Collateral Received			Net Amount(2)
	Derivatives	$	8,712	$	—		$	(644	)	$	8,068	$	5,476		$	—		$	(181	)	$	5,295
	Resale agreements and securities borrowing	18,386		(108		)	(18,185		)	93		17,521			(131		)	(14,983		)	2,407
	Total	$	27,098	$	(108	)	$	(18,829	)	$	8,161	$	22,997		$	(131	)	$	(15,164	)	$	7,702
	(1) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(2) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.
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:	30-Sep-14								31-Dec-13
	(In millions)	Gross Amounts of Recognized Liabilities(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Liabilities Presented in Statement of Condition			Gross Amounts of Recognized Liabilities(1)		Gross Amounts Offset in Statement of Condition(2)			Net Amounts of Liabilities Presented in Statement of Condition
	Derivatives:
	Foreign exchange contracts	$	16,559	$	(7,345	)	$	9,214		$	11,471	$	(4,514	)	$	6,957
	Interest-rate contracts	241		(34		)	207			331		(59		)	272
	Other derivative contracts	73		—			73			9		—			9
	Cash collateral netting	—		(2,581		)	(2,581		)	—		(979		)	(979		)
	Total derivatives	$	16,873	$	(9,960	)	$	6,913		$	11,811	$	(5,552	)	$	6,259
	Other financial instruments:
	Repurchase agreements and securities lending(3)	$	46,089	$	(29,692	)	$	16,397		$	45,273	$	(30,700	)	$	14,573
	Total derivatives and other financial instruments	$	62,962	$	(39,652	)	$	23,310		$	57,084	$	(36,252	)	$	20,832
	(1) Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
	(2) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(3) Included in the $16,397 million as of September 30, 2014 were $9,385 million of repurchase agreements and $7,012 million of collateral received related to securities lending. Included in the $14,573 million as of December 31, 2013 were $7,953 million of repurchase agreements and $6,620 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 liabilities, respectively, in our consolidated statement of condition. Refer to note 7 for additional information with respect to principal securities finance transactions.
		30-Sep-14										31-Dec-13
				Gross Amounts Not Offset in Statement of Condition(1)											Gross Amounts Not Offset in Statement of Condition(1)
	(In millions)	Net Amount of Liabilities Presented in Statement of Condition		Counterparty Netting			Collateral Provided			Net Amount(2)		Net Amount of Liabilities Presented in Statement of Condition			Counterparty Netting			Collateral Provided			Net Amount(2)
	Derivatives	$	6,913	$	—		$	(78	)	$	6,835	$	6,259		$	—		$	(6	)	$	6,253
	Repurchase agreements and securities lending	16,397		(108		)	(14,173		)	2,116		14,573			(131		)	(13,036		)	1,406
	Total	$	23,310	$	(108	)	$	(14,251	)	$	8,951	$	20,832		$	(131	)	$	(13,042	)	$	7,659
	(1) Amounts subject to netting arrangements which have been determined to be legally enforceable.
	(2) Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.

Net_Interest_Revenue_Tables

Net Interest Revenue (Tables)	9 Months Ended
	Sep. 30, 2014
Net Interest Revenue [Abstract]	'
Components of Interest Revenue and Interest Expense	'
	The following table presents the components of interest revenue and interest expense, and related net interest revenue, for the periods indicated:
		Three Months Ended September 30,				Nine Months Ended September 30,
	(In millions)	2014		2013		2014		2013
	Interest revenue:
	Deposits with banks	$	53	$	29	$	138	$	91
	Investment securities:
	U.S. Treasury and federal agencies	165		165		493		542
	State and political subdivisions	58		59		173		164
	Other investments	320		323		957		1,003
	Securities purchased under resale agreements	9		8		27		33
	Loans and leases	64		58		183		193
	Other interest-earning assets	2		1		5		4
	Total interest revenue	671		643		1,976		2,030
	Interest expense:
	Deposits	33		17		66		78
	Short-term borrowings	—		15		4		46
	Long-term debt	60		59		186		169
	Other interest-bearing liabilities	8		6		34		19
	Total interest expense	101		97		290		312
	Net interest revenue	$	570	$	546	$	1,686	$	1,718

Expenses_Tables

Expenses (Tables)	9 Months Ended
	Sep. 30, 2014
Other Expenses [Abstract]	'
Schedule of Acquisition and Restructuring Costs	'
	The following table presents net acquisition and restructuring costs recorded in the periods indicated:
			Three Months Ended September 30,						Nine Months Ended September 30,
	(In millions)		2014			2013			2014			2013
	Acquisition costs		$	12		$	18		$	48		$	52
	Restructuring charges, net		8			12			33			22
	Total acquisition and restructuring costs		$	20		$	30		$	81		$	74
Costs Related to Acquisition and Restructuring	'
	(In millions)	Employee-			Real Estate Consolidation			Asset and Other Write-Offs			Total
		Related
		Costs
	Balance as of December 31, 2013	$	50		$	49		$	7		$	106
	Additional accruals for Business Operations and Information Technology Transformation program	14			7			—			21
	Additional accruals for 2012 expense control measures	1			—			11			12
	Payments and adjustments	(37		)	(36		)	(7		)	(80		)
	Balance as of September 30, 2014	$	28		$	20		$	11		$	59

Earnings_Per_Common_Share_Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Computation of Basic and Diluted Earnings Per Share	'
	The following tables present the computation of basic and diluted earnings per common share for the periods indicated:
		Three Months Ended September 30,
	(Dollars in millions, except per share amounts)	2014			2013
	Net income	$	560		$	540
	Less:
	Preferred stock dividends	(18		)	(7		)
	Dividends and undistributed earnings allocated to participating securities(1)	—			(2		)
	Net income available to common shareholders	$	542		$	531
	Average common shares outstanding (in thousands):
	Basic average common shares	421,974			442,860
	Effect of dilutive securities: common stock options and common stock awards	7,762			9,294
	Diluted average common shares	429,736			452,154
	Anti-dilutive securities(2)	876			1,788
	Earnings per Common Share:
	Basic	$	1.28		$	1.2
	Diluted(3)	1.26			1.17
		Nine Months Ended September 30,
	(Dollars in millions, except per share amounts)	2014			2013
	Net income	$	1,545		$	1,583
	Less:
	Preferred stock dividends	(43		)	(20		)
	Dividends and undistributed earnings allocated to participating securities(1)	(2		)	(6		)
	Net income available to common shareholders	$	1,500		$	1,557
	Average common shares outstanding (in thousands):
	Basic average common shares	426,775			449,742
	Effect of dilutive securities: common stock options and common stock awards	7,735			8,650
	Diluted average common shares	434,510			458,392
	Anti-dilutive securities(2)	1,502			2,384
	Earnings per Common Share:
	Basic	$	3.52		$	3.46
	Diluted(3)	3.45			3.4
	(1) Represented the portion of net income available to common equity allocated to participating securities, composed of fully vested deferred director stock and unvested restricted stock that contain non-forfeitable rights to dividends during the vesting period on a basis equivalent to dividends paid to common shareholders.
	(2) Represented common stock options and other equity-based awards outstanding but not included in the computation of diluted average common shares, because their effect was anti-dilutive.
	(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)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Summary of Line of Business Results	'
		Nine Months Ended September 30,
		Investment						Investment						Other						Total
		Servicing						Management
		2014			2013			2014			2013			2014			2013			2014			2013
	(Dollars in millions,
	except where otherwise noted)
	Fee revenue:
	Servicing fees	$	3,828		$	3,587		$	—		$	—		$	—		$	—		$	3,828		$	3,587
	Management fees	—			—			908			816			—			—			908			816
	Trading services	756			803			35			55			—			—			791			858
	Securities finance	331			283			—			—			—			—			331			283
	Processing fees and other	122			157			(5		)	10			—			—			117			167
	Total fee revenue	5,037			4,830			938			881			—			—			5,975			5,711
	Net interest revenue	1,634			1,655			52			63			—			—			1,686			1,718
	Gains (losses) related to investment securities, net	4			(9		)	—			—			—			—			4			(9		)
	Total revenue	6,675			6,476			990			944			—			—			7,665			7,420
	Provision for loan losses	6			—			—			—			—			—			6			—
	Total expenses	4,905			4,639			708			613			157			94			5,770			5,346
	Income before income tax expense	$	1,764		$	1,837		$	282		$	331		$	(157	)	$	(94	)	$	1,889		$	2,074
	Pre-tax margin	26		%	28		%	28		%	35		%							25		%	28		%
	Average assets (in billions)	$	229		$	201.9		$	3.6		$	3.8								$	232.6		$	205.7

NonUS_Activities_Tables

Non-U.S. Activities (Tables)	9 Months Ended
	Sep. 30, 2014
Segments, Geographical Areas [Abstract]	'
Schedule of Results from Non-U.S. Operations	'
	The following table presents our non-U.S. financial results for the periods indicated.
		Three Months Ended September 30,
	(In millions)	2014		2013
	Total fee revenue	$	862	$	771
	Net interest revenue	325		306
	Gains (losses) related to investment securities, net	1		(2		)
	Total revenue	1,188		1,075
	Expenses	791		786
	Income before income taxes	397		289
	Income tax expense	96		74
	Net income	$	301	$	215
		Nine Months Ended September 30,
	(In millions)	2014		2013
	Total fee revenue	$	2,488	$	2,347
	Net interest revenue	991		874
	Gains (losses) related to investment securities, net	6		(12		)
	Total revenue	3,485		3,209
	Expenses	2,443		2,279
	Income before income taxes	1,042		930
	Income tax expense	248		228
	Net income	$	794	$	702
Summary of Non-U.S. Assets	'
	The following table presents the significant components of our non-U.S. assets as of the dates indicated, based on the domicile of the underlying counterparties:
	(In millions)	September 30, 2014		December 31, 2013
	Interest-bearing deposits with banks	$	9,828	$	9,584
	Investment securities	30,791		31,522
	Other assets	17,326		16,778
	Total non-U.S. assets	$	57,945	$	57,884

Basis_of_Presentation_Details

Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2014
	line_of_business
Accounting Policies [Abstract]	'
Number of lines of business	2

Fair_Value_Narrative_Details

Fair Value (Narrative) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'	'
Fair value measurements with unobservable inputs, percent of total financial assets	5.00%	'
Percent of level 3 portfolio priced using non-binding broker quotes	98.00%	98.00%
Percent of level 3 portfolio priced using internal model pricing	2.00%	2.00%
Assets, level 1 to level 2 transfers	$0	$0
Assets, level 2 to level 1 transfers	0	0
Liabilities, level 1 to level 2 transfers	0	0
Liabilities, level 2 to level 1 transfers	$0	$0

Fair_Value_Schedule_of_Fair_Va

Fair Value (Schedule of Fair Value Measurements on a Recurring Basis) (Details) (USD $)	9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	$1,033		$843
Investment securities available for sale	96,552		99,174
Reduction in assets from netting and the result of cash collateral deposited with derivative counterparties	841		1,930
Reduction in liabilities from netting and the result of cash collateral received from derivative counterparties	2,580		979
Pricing Methods with Significant Unobservable Market Inputs (Level 3)	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Assets, fair value disclosure	5,543		7,564
Liabilities, fair value disclosure	68		26
Recurring	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	1,033		843
Investment securities available for sale	96,552		99,174
Derivative assets	8,712		5,476
Other assets	115		97
Assets, fair value disclosure	106,412		105,590
Derivative liabilities	6,913		6,259
Other liabilities	115		97
Liabilities, fair value disclosure	7,173		6,356
Recurring | Foreign exchange contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	8,703		5,469
Derivative liabilities	6,648		6,013
Recurring | Interest-rate contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	5		6
Derivative liabilities	192		237
Recurring | Other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	4		1
Derivative liabilities	73		9
Recurring | U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	37		20
Trading account liabilities	92		'
Recurring | Non-U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	479		399
Trading account liabilities	50		'
Recurring | Other U.S. debt securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	517		424
Investment securities available for sale	4,284		4,980
Trading account liabilities	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	10,764		709
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	21,201		23,563
Recurring | Total asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	21,257		29,019
Recurring | Asset-backed securities, student loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	12,806		14,542
Recurring | Asset-backed securities, credit cards	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	3,111		8,210
Recurring | Asset-backed securities, sub-prime	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	997		1,203
Recurring | Asset-backed securities, other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	4,343		5,064
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	23,148		24,907
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	10,239		11,029
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	3,447		5,390
Recurring | Non-US debt securities, government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	3,613		3,761
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	5,849		4,727
Recurring | State and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	10,645		10,263
Recurring | Collateralized mortgage obligations	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	4,671		5,269
Recurring | U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	38		34
Recurring | Non-U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	2		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	532		422
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	10		7
Recurring | Quoted Market Prices in Active Markets (Level 1)	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	568		486
Investment securities available for sale	10,139		0
Derivative assets	0		0
Other assets	115		97
Assets, fair value disclosure	10,822		583
Derivative liabilities	0		0
Other liabilities	115		97
Liabilities, fair value disclosure	260		97
Recurring | Quoted Market Prices in Active Markets (Level 1) | Foreign exchange contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	0		0
Derivative liabilities	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Interest-rate contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	0		0
Derivative liabilities	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	0		0
Derivative liabilities	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	37		20
Trading account liabilities	92		'
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	479		399
Trading account liabilities	50		'
Recurring | Quoted Market Prices in Active Markets (Level 1) | Other U.S. debt securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	52		67
Investment securities available for sale	0		0
Trading account liabilities	3		'
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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	10,139		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | Total asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | Asset-backed securities, sub-prime	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Asset-backed securities, other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-US debt securities, government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | State and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Collateralized mortgage obligations	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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
Recurring | Quoted Market Prices in Active Markets (Level 1) | 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		0
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2)	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	465		357
Investment securities available for sale	80,938		91,629
Derivative assets	16,864		11,958
Other assets	0		0
Assets, fair value disclosure	98,267		103,944
Derivative liabilities	16,805		11,785
Other liabilities	0		0
Liabilities, fair value disclosure	16,805		11,785
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Foreign exchange contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	16,797		11,892
Derivative liabilities	16,500		11,454
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Interest-rate contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	63		65
Derivative liabilities	241		331
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	4		1
Derivative liabilities	64		0
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	0		0
Trading account liabilities	0		'
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	0		0
Trading account liabilities	0		'
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Other U.S. debt securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	465		357
Investment securities available for sale	4,276		4,972
Trading account liabilities	0		'
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | 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	625		709
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | 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	20,941		22,847
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Total asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	17,047		24,040
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, student loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	12,540		14,119
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, credit cards	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	3,111		8,186
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, sub-prime	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	997		1,203
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	399		532
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Total non-U.S. debt securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	22,426		23,270
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | 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	10,239		10,654
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | 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	3,023		4,592
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-US debt securities, government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	3,613		3,761
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. debt securities, other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	5,551		4,263
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | State and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	10,604		10,220
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Collateralized mortgage obligations	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	4,437		5,107
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	38		34
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	2		1
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | U.S. money-market mutual funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	532		422
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | 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	10		7
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3)	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	0		0
Investment securities available for sale	5,475		7,545
Derivative assets	68		19
Other assets	0		0
Assets, fair value disclosure	5,543		7,564
Derivative liabilities	68		26
Other liabilities	0		0
Liabilities, fair value disclosure	68		26
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Foreign exchange contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	68		19
Derivative liabilities	59		17
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Interest-rate contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	0		0
Derivative liabilities	0		0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	0		0
Derivative liabilities	9		9
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	0		0
Trading account liabilities	0		'
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	0		0
Trading account liabilities	0		'
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other U.S. debt securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Trading account assets	0		0
Investment securities available for sale	8		8
Trading account liabilities	0		'
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | 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
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | 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	260		716
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Total asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	4,210		4,979
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	266		423
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		24
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, sub-prime	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	3,944		4,532
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Total non-U.S. debt securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	722		1,637
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | 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		375
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | 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	424		798
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-US debt securities, government securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	298		464
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	41		43
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Collateralized mortgage obligations	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	234		162
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. equity securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Investment securities available for sale	0		0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | 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
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | 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		0
Recurring | Impact of Netting	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	-8,220	[1]	-6,501	[2]
Other assets	0	[1]	0	[2]
Assets, fair value disclosure	-8,220	[1]	-6,501	[2]
Derivative liabilities	-9,960	[1]	-5,552	[2]
Other liabilities	0	[1]	0	[2]
Liabilities, fair value disclosure	-9,960	[1]	-5,552	[2]
Recurring | Impact of Netting | Foreign exchange contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	-8,162	[1]	-6,442	[2]
Derivative liabilities	-9,911	[1]	-5,458	[2]
Recurring | Impact of Netting | Interest-rate contracts	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	-58	[1]	-59	[2]
Derivative liabilities	-49	[1]	-94	[2]
Recurring | Impact of Netting | Other	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets	0	[1]	0	[2]
Derivative liabilities	$0	[1]	$0	[2]
[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 $841 million and $2.58 billion, respectively, for cash collateral received from and provided to derivative counterparties.
[2]	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 $1.93 billion and $979 million, respectively, for cash collateral received from and provided to derivative counterparties.

Fair_Value_Schedule_of_Fair_Va1

Fair Value (Schedule of Fair Value Measurements, Assets, Using Significant Unobservable Inputs) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	$5,756	$6,894	$7,564	$6,980
Recorded in Revenue, Assets	64	-7	79	165
Recorded in Other Comprehensive Income, Assets	-10	-15	-12	25
Purchases, Assets	614	1,163	766	2,392
Issuances, Assets	0	0	0	0
Sales, Assets	-74	-24	-81	-59
Settlements, Assets	-551	-349	-1,249	-1,481
Transfers into Level 3, Assets	76	15	76	154
Transfers out of Level 3, Assets	-332	-297	-1,600	-796
Fair value as of end of period	5,543	7,380	5,543	7,380
Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of period end	40	-16	35	29
Derivative instruments, assets	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	10	121	19	113
Recorded in Revenue, Assets	44	-21	26	119
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	22	7	32	25
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	-8	-30	-9	-180
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Fair value as of end of period	68	77	68	77
Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of period end	40	-16	35	29
Foreign exchange contracts	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	10	121	19	113
Recorded in Revenue, Assets	44	-21	26	119
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	22	7	32	25
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	-8	-30	-9	-180
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Fair value as of end of period	68	77	68	77
Change in Unrealized Gains (Losses) Related to Financial Instruments Held as of period end	40	-16	35	29
Categories of investments, marketable securities, available-for-sale securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	5,746	6,773	7,545	6,867
Recorded in Revenue, Assets	20	14	53	46
Recorded in Other Comprehensive Income, Assets	-10	-15	-12	25
Purchases, Assets	592	1,156	734	2,367
Issuances, Assets	0	0	0	0
Sales, Assets	-74	-24	-81	-59
Settlements, Assets	-543	-319	-1,240	-1,301
Transfers into Level 3, Assets	76	15	76	154
Transfers out of Level 3, Assets	-332	-297	-1,600	-796
Fair value as of end of period	5,475	7,303	5,475	7,303
Categories of investments, marketable securities, available-for-sale securities | US Treasury and federal agencies, mortgage-backed securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	96	864	716	825
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	0	-1	0	-1
Purchases, Assets	168	0	168	92
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	-4	-29	-14	-83
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	-93	-610	-92
Fair value as of end of period	260	741	260	741
Categories of investments, marketable securities, available-for-sale securities | Total asset-backed securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	4,383	4,252	4,979	4,649
Recorded in Revenue, Assets	18	13	47	41
Recorded in Other Comprehensive Income, Assets	-9	-7	-12	31
Purchases, Assets	299	793	306	1,358
Issuances, Assets	0	0	0	0
Sales, Assets	-74	-24	-74	-59
Settlements, Assets	-407	-285	-957	-1,103
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	-79	-175
Fair value as of end of period	4,210	4,742	4,210	4,742
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, student loans	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	322	380	423	588
Recorded in Revenue, Assets	0	0	1	1
Recorded in Other Comprehensive Income, Assets	-1	-2	2	6
Purchases, Assets	24	0	24	0
Issuances, Assets	0	0	0	0
Sales, Assets	-74	0	-74	-26
Settlements, Assets	-5	-10	-31	-26
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	-79	-175
Fair value as of end of period	266	368	266	368
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, credit cards	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	'	24	24	67
Recorded in Revenue, Assets	'	0	0	0
Recorded in Other Comprehensive Income, Assets	'	0	0	0
Purchases, Assets	'	0	0	0
Issuances, Assets	'	0	0	0
Sales, Assets	'	0	0	0
Settlements, Assets	'	0	-24	-43
Transfers into Level 3, Assets	'	0	0	0
Transfers out of Level 3, Assets	'	0	0	0
Fair value as of end of period	0	24	0	24
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, other	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	4,061	3,848	4,532	3,994
Recorded in Revenue, Assets	18	13	46	40
Recorded in Other Comprehensive Income, Assets	-8	-5	-14	25
Purchases, Assets	275	793	282	1,358
Issuances, Assets	0	0	0	0
Sales, Assets	0	-24	0	-33
Settlements, Assets	-402	-275	-902	-1,034
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Fair value as of end of period	3,944	4,350	3,944	4,350
Categories of investments, marketable securities, available-for-sale securities | Total non-U.S. debt securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	1,021	1,365	1,637	1,219
Recorded in Revenue, Assets	2	1	5	4
Recorded in Other Comprehensive Income, Assets	-1	-1	0	1
Purchases, Assets	0	313	55	727
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	-1	0
Settlements, Assets	-124	6	-247	-81
Transfers into Level 3, Assets	76	0	76	139
Transfers out of Level 3, Assets	-252	-104	-803	-429
Fair value as of end of period	722	1,580	722	1,580
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, mortgage-backed securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	'	328	375	555
Recorded in Revenue, Assets	'	0	0	0
Recorded in Other Comprehensive Income, Assets	'	-1	0	-1
Purchases, Assets	'	0	0	0
Issuances, Assets	'	0	0	0
Sales, Assets	'	0	0	0
Settlements, Assets	'	13	0	-6
Transfers into Level 3, Assets	'	0	0	0
Transfers out of Level 3, Assets	'	0	-375	-208
Fair value as of end of period	0	340	0	340
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, asset-backed securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	506	756	798	524
Recorded in Revenue, Assets	2	1	5	4
Recorded in Other Comprehensive Income, Assets	-1	1	0	2
Purchases, Assets	0	164	0	399
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	-99	-19	-219	-88
Transfers into Level 3, Assets	76	0	76	139
Transfers out of Level 3, Assets	-60	-104	-236	-181
Fair value as of end of period	424	799	424	799
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, other	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	515	281	464	140
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	0	-1	0	0
Purchases, Assets	0	149	55	328
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	-1	0
Settlements, Assets	-25	12	-28	13
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	-192	0	-192	-40
Fair value as of end of period	298	441	298	441
Categories of investments, marketable securities, available-for-sale securities | State and political subdivisions	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	41	45	43	48
Recorded in Revenue, Assets	0	0	1	0
Recorded in Other Comprehensive Income, Assets	0	-1	-1	-1
Purchases, Assets	0	0	0	0
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	0	0	-2	-3
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Fair value as of end of period	41	44	41	44
Categories of investments, marketable securities, available-for-sale securities | Collateralized mortgage obligations	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	196	238	162	117
Recorded in Revenue, Assets	0	0	0	1
Recorded in Other Comprehensive Income, Assets	0	-5	1	-5
Purchases, Assets	125	50	205	190
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	-6	0
Settlements, Assets	-7	-11	-20	-31
Transfers into Level 3, Assets	0	15	0	15
Transfers out of Level 3, Assets	-80	-100	-108	-100
Fair value as of end of period	234	187	234	187
Categories of investments, marketable securities, available-for-sale securities | Other U.S. debt securities	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair value as of beginning of period	9	9	8	9
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	0	0	0	0
Issuances, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	-1	0	0	0
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Fair value as of end of period	$8	$9	$8	$9

Fair_Value_Schedule_of_Fair_Va2

Fair Value (Schedule of Fair Value Measurements, Liabilities, Using Significant Unobservable Inputs) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair Value, beginning balance, Liabilities	$19	$117	$26	$115
Recorded in Revenue, Liabilities	36	-17	22	59
Recorded in Other Comprehensive Income, Liabilities	0	0	0	0
Purchases, Liabilities	0	0	0	0
Issuances, Liabilities	18	5	28	24
Sales, Liabilities	0	0	0	0
Settlements, Liabilities	-5	-41	-8	-134
Transfers in	0	0	0	0
Transfers out	0	0	0	0
Fair Value, ending balance, Liabilities	68	64	68	64
Change in Unrealized (Gains) Losses Related to Financial Instruments Held as of end of period	35	-15	32	15
Derivative instruments, liabilities | Accrued expenses and other liabilities	'	'	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair Value, beginning balance, Liabilities	19	117	26	115
Recorded in Revenue, Liabilities	36	-17	22	59
Recorded in Other Comprehensive Income, Liabilities	0	0	0	0
Purchases, Liabilities	0	0	0	0
Issuances, Liabilities	18	5	28	24
Sales, Liabilities	0	0	0	0
Settlements, Liabilities	-5	-41	-8	-134
Transfers in	0	0	0	0
Transfers out	0	0	0	0
Fair Value, ending balance, Liabilities	68	64	68	64
Change in Unrealized (Gains) Losses Related to Financial Instruments Held as of end of period	35	-15	32	15
Foreign exchange contracts | Accrued expenses and other liabilities	'	'	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair Value, beginning balance, Liabilities	10	108	17	106
Recorded in Revenue, Liabilities	36	-17	22	59
Recorded in Other Comprehensive Income, Liabilities	0	0	0	0
Purchases, Liabilities	0	0	0	0
Issuances, Liabilities	18	5	28	24
Sales, Liabilities	0	0	0	0
Settlements, Liabilities	-5	-41	-8	-134
Transfers in	0	0	0	0
Transfers out	0	0	0	0
Fair Value, ending balance, Liabilities	59	55	59	55
Change in Unrealized (Gains) Losses Related to Financial Instruments Held as of end of period	35	-15	32	15
Other | Accrued expenses and other liabilities	'	'	'	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'
Fair Value, beginning balance, Liabilities	9	9	9	9
Recorded in Revenue, Liabilities	0	0	0	0
Recorded in Other Comprehensive Income, Liabilities	0	0	0	0
Purchases, Liabilities	0	0	0	0
Issuances, Liabilities	0	0	0	0
Sales, Liabilities	0	0	0	0
Settlements, Liabilities	0	0	0	0
Transfers in	0	0	0	0
Transfers out	0	0	0	0
Fair Value, ending balance, Liabilities	9	9	9	9
Change in Unrealized (Gains) Losses Related to Financial Instruments Held as of end of period	$0	$0	$0	$0

Fair_Value_Level_3_Total_Reali

Fair Value (Level 3 Total Realized And Unrealized Gains And Losses Recorded In Revenue) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Total Revenue [Member]	'	'	'	'
Realized and Unrealized Gains and Losses [Line Items]	'	'	'	'
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	$28	$10	$57	$106
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	5	-1	3	14
Trading services	'	'	'	'
Realized and Unrealized Gains and Losses [Line Items]	'	'	'	'
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	8	-4	4	60
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	5	-1	3	14
Total fee revenue	'	'	'	'
Realized and Unrealized Gains and Losses [Line Items]	'	'	'	'
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	8	-4	4	60
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	5	-1	3	14
Net interest revenue	'	'	'	'
Realized and Unrealized Gains and Losses [Line Items]	'	'	'	'
Total Realized and Unrealized Gains (Losses) Recorded in Revenue	20	14	53	46
Change in Unrealized Gains (Losses) Related to Financial Instruments Held	$0	$0	$0	$0

Fair_Value_Fair_Value_Inputs_A

Fair Value (Fair Value Inputs, Assets and Liabilities, Quantitative Information) (Details) (USD $)	9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	96,552		99,174
Asset-backed securities, student loans	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	12,806	[1]	14,542	[1]
Asset-backed securities, credit cards	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	3,111		8,210
Asset-backed securities, other	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	4,343		5,064
Non-U.S. debt securities, other	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	5,849		4,727
State and political subdivisions	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	10,645		10,263
Pricing Methods with Significant Unobservable Market Inputs (Level 3)	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Assets, fair value disclosure	5,543		7,564
Liabilities, fair value disclosure	68		26
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, liabilities	59		17
Derivative instruments, other, liabilities	9		9
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, assets	68		19
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	266		423
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	'		24
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	3,944		4,532
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, other	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	298		464
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	41		43
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Derivative instruments, liabilities | Weighted average	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Participant redemptions	6.00%		7.50%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Asset-backed securities, student loans | Weighted average	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Credit spread	0.00%		3.50%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Discounted cash flows | Asset-backed securities, credit cards | Weighted average	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Credit spread	0.00%		2.00%
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	0.20%		1.50%
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	1.60%		1.70%
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	7.70%		11.20%
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	7.70%		11.40%
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member]	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Assets, fair value disclosure	175	[2]	191	[2]
Liabilities, fair value disclosure	68	[2]	26	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, liabilities	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Derivative instruments, foreign exchange contracts, liabilities	59	[2]	17	[2]
Derivative instruments, other, liabilities	9	[2],[3]	9	[2],[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, assets	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Derivative instruments, foreign exchange contracts, assets	68	[2]	19	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, student loans	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	0	[2]	13	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, credit cards	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	0		24	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, other	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	66	[2]	92	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, other	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | State and political subdivisions	'		'
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]	'		'
Investment securities available for sale	41	[2]	43	[2]
[1]	Substantially 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]	Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.
[3]	Relates to stable value wrap contracts; refer to the sensitivity discussion following the tables presented below, and to note 7.

Fair_Value_Schedule_of_Availab

Fair Value (Schedule of Availability of Significant Unobservable Inputs by Balance Sheet Classification) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Assets:	'		'
Investment securities available for sale	$96,552		$99,174
Asset-backed securities, student loans	'		'
Assets:	'		'
Investment securities available for sale	12,806	[1]	14,542	[1]
Asset-backed securities, credit cards	'		'
Assets:	'		'
Investment securities available for sale	3,111		8,210
Asset-backed securities, other	'		'
Assets:	'		'
Investment securities available for sale	4,343		5,064
Non-U.S. debt securities, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	10,239		11,029
Non-U.S. debt securities, asset-backed securities	'		'
Assets:	'		'
Investment securities available for sale	3,447		5,390
Non-U.S. debt securities, other	'		'
Assets:	'		'
Investment securities available for sale	5,849		4,727
State and political subdivisions	'		'
Assets:	'		'
Investment securities available for sale	10,645		10,263
Collateralized mortgage obligations	'		'
Assets:	'		'
Investment securities available for sale	4,671		5,269
Other U.S. debt securities	'		'
Assets:	'		'
Investment securities available for sale	4,284		4,980
Pricing Methods with Significant Unobservable Market Inputs (Level 3)	'		'
Assets:	'		'
Assets, fair value disclosure	5,543		7,564
Liabilities:	'		'
Liabilities, fair value disclosure	68		26
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, liabilities	'		'
Liabilities:	'		'
Derivative instruments, foreign exchange contracts, liabilities	59		17
Derivative instruments, other, liabilities	9		9
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Derivative instruments, assets	'		'
Assets:	'		'
Derivative instruments, foreign exchange contracts, assets	68		19
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. Treasury and federal agencies, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	260		716
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans	'		'
Assets:	'		'
Investment securities available for sale	266		423
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards	'		'
Assets:	'		'
Investment securities available for sale	'		24
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other	'		'
Assets:	'		'
Investment securities available for sale	3,944		4,532
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	'		375
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, asset-backed securities	'		'
Assets:	'		'
Investment securities available for sale	424		798
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, other	'		'
Assets:	'		'
Investment securities available for sale	298		464
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions	'		'
Assets:	'		'
Investment securities available for sale	41		43
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Collateralized mortgage obligations	'		'
Assets:	'		'
Investment securities available for sale	234		162
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other U.S. debt securities	'		'
Assets:	'		'
Investment securities available for sale	8		8
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member]	'		'
Assets:	'		'
Assets, fair value disclosure	175	[2]	191	[2]
Liabilities:	'		'
Liabilities, fair value disclosure	68	[2]	26	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, liabilities	'		'
Liabilities:	'		'
Derivative instruments, foreign exchange contracts, liabilities	59	[2]	17	[2]
Derivative instruments, other, liabilities	9	[2],[3]	9	[2],[3]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Derivative instruments, assets	'		'
Assets:	'		'
Derivative instruments, foreign exchange contracts, assets	68	[2]	19	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | U.S. Treasury and federal agencies, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, student loans	'		'
Assets:	'		'
Investment securities available for sale	0	[2]	13	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, credit cards	'		'
Assets:	'		'
Investment securities available for sale	0		24	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Asset-backed securities, other	'		'
Assets:	'		'
Investment securities available for sale	66	[2]	92	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	'		0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, asset-backed securities	'		'
Assets:	'		'
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Non-U.S. debt securities, other	'		'
Assets:	'		'
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | State and political subdivisions	'		'
Assets:	'		'
Investment securities available for sale	41	[2]	43	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Collateralized mortgage obligations	'		'
Assets:	'		'
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Readily Available [Member] | Other U.S. debt securities	'		'
Assets:	'		'
Investment securities available for sale	0	[2]	0	[2]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member]	'		'
Assets:	'		'
Assets, fair value disclosure	5,368	[4]	7,373	[4]
Liabilities:	'		'
Liabilities, fair value disclosure	0	[4]	0	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Derivative instruments, liabilities	'		'
Liabilities:	'		'
Derivative instruments, foreign exchange contracts, liabilities	0	[4]	0	[4]
Derivative instruments, other, liabilities	0	[4]	0	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Derivative instruments, assets	'		'
Assets:	'		'
Derivative instruments, foreign exchange contracts, assets	0	[4]	0	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | U.S. Treasury and federal agencies, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	260	[4]	716	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, student loans	'		'
Assets:	'		'
Investment securities available for sale	266	[4]	410	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, credit cards	'		'
Assets:	'		'
Investment securities available for sale	'		0	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Asset-backed securities, other	'		'
Assets:	'		'
Investment securities available for sale	3,878	[4]	4,440	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, mortgage-backed securities	'		'
Assets:	'		'
Investment securities available for sale	'		375	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, asset-backed securities	'		'
Assets:	'		'
Investment securities available for sale	424	[4]	798	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Non-U.S. debt securities, other	'		'
Assets:	'		'
Investment securities available for sale	298	[4]	464	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | State and political subdivisions	'		'
Assets:	'		'
Investment securities available for sale	0	[4]	0	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Collateralized mortgage obligations	'		'
Assets:	'		'
Investment securities available for sale	234	[4]	162	[4]
Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Significant Unobservable Inputs Not Readily Available [Member] | Other U.S. debt securities	'		'
Assets:	'		'
Investment securities available for sale	$8	[4]	$8	[4]
[1]	Substantially 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]	Information with respect to these model-priced financial assets and liabilities is provided above in a separate table.
[3]	Relates to stable value wrap contracts; refer to the sensitivity discussion following the tables presented below, and to note 7.
[4]	Fair value for these financial assets is measured using non-binding broker or dealer quotes.

Fair_Value_Carrying_Value_and_

Fair Value (Carrying Value and Estimated Fair Value of Financial Instruments) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Financial Assets:	'	'	'	'
Cash and due from banks	$4,146	$3,220	$3,896	$2,590
Interest-bearing deposits with banks	86,946	64,257	'	'
Securities purchased under resale agreements	2,603	6,230	'	'
Investment securities held to maturity, fair value	18,865	17,560	'	'
Net loans (excluding leases)	17,287	12,355	'	'
Financial Liabilities:	'	'	'	'
Noninterest-bearing	66,134	65,614	'	'
Interest-bearing—U.S.	24,435	13,392	'	'
Interest-bearing—non-U.S.	117,399	103,262	'	'
Securities sold under repurchase agreements	9,385	7,953	'	'
Federal funds purchased	17	19	'	'
Other short-term borrowings	4,307	3,780	'	'
Long-term debt	9,352	9,909	'	'
Reported Amount	'	'	'	'
Financial Assets:	'	'	'	'
Cash and due from banks	4,146	3,220	'	'
Interest-bearing deposits with banks	86,946	64,257	'	'
Securities purchased under resale agreements	2,603	6,230	'	'
Investment securities held to maturity, fair value	18,767	17,740	'	'
Net loans (excluding leases)	17,296	12,363	'	'
Financial Liabilities:	'	'	'	'
Noninterest-bearing	66,134	65,614	'	'
Interest-bearing—U.S.	24,435	13,392	'	'
Interest-bearing—non-U.S.	117,399	103,262	'	'
Securities sold under repurchase agreements	9,385	7,953	'	'
Federal funds purchased	17	19	'	'
Other short-term borrowings	4,307	3,780	'	'
Long-term debt	9,016	9,699	'	'
Quoted Market Prices in Active Markets (Level 1)	'	'	'	'
Financial Assets:	'	'	'	'
Cash and due from banks	4,146	3,220	'	'
Interest-bearing deposits with banks	0	0	'	'
Securities purchased under resale agreements	0	0	'	'
Investment securities held to maturity, fair value	0	0	'	'
Net loans (excluding leases)	0	0	'	'
Financial Liabilities:	'	'	'	'
Noninterest-bearing	0	0	'	'
Interest-bearing—U.S.	0	0	'	'
Interest-bearing—non-U.S.	0	0	'	'
Securities sold under repurchase agreements	0	0	'	'
Federal funds purchased	0	0	'	'
Other short-term borrowings	0	0	'	'
Long-term debt	0	0	'	'
Pricing Methods with Significant Observable Market Inputs (Level 2)	'	'	'	'
Financial Assets:	'	'	'	'
Cash and due from banks	0	0	'	'
Interest-bearing deposits with banks	86,946	64,257	'	'
Securities purchased under resale agreements	2,603	6,230	'	'
Investment securities held to maturity, fair value	18,865	17,560	'	'
Net loans (excluding leases)	16,830	11,908	'	'
Financial Liabilities:	'	'	'	'
Noninterest-bearing	66,134	65,614	'	'
Interest-bearing—U.S.	24,435	13,392	'	'
Interest-bearing—non-U.S.	117,399	103,262	'	'
Securities sold under repurchase agreements	9,385	7,953	'	'
Federal funds purchased	17	19	'	'
Other short-term borrowings	4,307	3,780	'	'
Long-term debt	8,474	9,056	'	'
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, fair value	0	0	'	'
Net loans (excluding leases)	457	447	'	'
Financial Liabilities:	'	'	'	'
Noninterest-bearing	0	0	'	'
Interest-bearing—U.S.	0	0	'	'
Interest-bearing—non-U.S.	0	0	'	'
Securities sold under repurchase agreements	0	0	'	'
Federal funds purchased	0	0	'	'
Other short-term borrowings	0	0	'	'
Long-term debt	$878	$853	'	'

Investment_Securities_Narrativ

Investment Securities (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
	country		security
			country
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Pledged Financial Instruments, Not Separately Reported, Securities	$44,770,000,000	'	$44,770,000,000	'	$46,990,000,000
Other-than-temporary impairment recorded	0	10,000,000	11,000,000	20,000,000	'
Number of peripheral european countries	4	'	4	'	'
Impairment associated with adverse changes in timing of expected future cash flows	0	2,000,000	1,000,000	6,000,000	'
Gross pre-tax unrealized losses on securities	'	'	-759,000,000	'	'
Number of available for sale and held to maturity securities in gross pre-tax unrealized loss position	'	'	1,459	'	'
Minimum	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Percentage change in additional house price declines	'	'	9.00%	'	'
Maximum	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Percentage change in additional house price declines	'	'	15.00%	'	'
Agency Securities	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	0	0	0	0	'
Asset-backed securities, student loans	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	0	0	0	0	'
Federal Family Education Loan Program	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Federal government credit support guarantee, percentage minimum	'	'	97.00%	'	'
Other-than-temporary impairment recorded	0	0	0	0	'
Collective credit support, percentage minimum	'	'	100.00%	'	'
Average remaining term	'	'	'4 years 7 months 1 day	'	'
Maximum concentration risk on credit instruments (less than)	'	'	800,000,000	'	'
U.S. Non-Agency Residential Mortgage-Backed Securities	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	0	0	0	0	'
Non-U.S. debt securities, mortgage-backed securities	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	1,000,000	'	1,000,000	6,000,000	'
Non-U.S. debt securities, mortgage-backed securities | European Periphery	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	'	6,000,000	'	6,000,000	'
Total exposure to asset backed securities	910,000,000	'	910,000,000	'	'
Aggregate pre-tax gross unrealized gain (loss) on available for sale securities	'	'	125,000,000	'	'
Available for sale, gross unrealized gains	'	'	126,000,000	'	'
Available for sale, gross unrealized losses	'	'	-1,000,000	'	'
Non-U.S. debt securities, mortgage-backed securities | Spain	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Total exposure to asset backed securities	173,000,000	'	173,000,000	'	'
Non-U.S. debt securities, mortgage-backed securities | Italy	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Total exposure to asset backed securities	555,000,000	'	555,000,000	'	'
Non-U.S. debt securities, mortgage-backed securities | Ireland	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Total exposure to asset backed securities	109,000,000	'	109,000,000	'	'
Non-U.S. debt securities, mortgage-backed securities | Portugal	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Total exposure to asset backed securities	73,000,000	'	73,000,000	'	'
Direct sovereign debt	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Total exposure to asset backed securities	0	'	0	'	'
State and political subdivisions	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	0	0	0	0	'
Collateralized mortgage obligations	'	'	'	'	'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'	'	'	'	'
Other-than-temporary impairment recorded	'	'	$10,000,000	$8,000,000	'

Investment_Securities_Schedule

Investment Securities (Schedule of Marketable Securities) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	$95,834		$99,159
Available for sale, gross unrealized gains	1,222		1,162
Available for sale, gross unrealized losses	504		1,147
Available for sale, fair value	96,552		99,174
Held to maturity, amortized cost	18,767		17,740
Held to maturity, gross unrealized gains	353		354
Held to maturity, gross unrealized losses	255		534
Held to maturity, fair value	18,865		17,560
Total asset-backed securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	21,227		29,188
Available for sale, gross unrealized gains	251		254
Available for sale, gross unrealized losses	221		423
Available for sale, fair value	21,257		29,019
Held to maturity, amortized cost	3,403		3,171
Held to maturity, gross unrealized gains	10		2
Held to maturity, gross unrealized losses	2		12
Held to maturity, fair value	3,411		3,161
US Treasury and federal agencies, direct obligations	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	10,751		702
Available for sale, gross unrealized gains	17		9
Available for sale, gross unrealized losses	4		2
Available for sale, fair value	10,764		709
Held to maturity, amortized cost	5,117		5,041
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	222		448
Held to maturity, fair value	4,895		4,593
US Treasury and federal agencies, mortgage-backed securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	21,203		23,744
Available for sale, gross unrealized gains	196		211
Available for sale, gross unrealized losses	198		392
Available for sale, fair value	21,201		23,563
Held to maturity, amortized cost	68		91
Held to maturity, gross unrealized gains	4		6
Held to maturity, gross unrealized losses	0		0
Held to maturity, fair value	72		97
Asset-backed securities, student loans	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	12,806		14,718	[1]
Available for sale, gross unrealized gains	122		92	[1]
Available for sale, gross unrealized losses	122		268	[1]
Available for sale, fair value	12,806	[1]	14,542	[1]
Held to maturity, amortized cost	1,873		1,627	[1]
Held to maturity, gross unrealized gains	5		0	[1]
Held to maturity, gross unrealized losses	1		10	[1]
Held to maturity, fair value	1,877	[1]	1,617	[1]
Asset-backed securities, credit cards	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	3,128		8,230
Available for sale, gross unrealized gains	13		21
Available for sale, gross unrealized losses	30		41
Available for sale, fair value	3,111		8,210
Held to maturity, amortized cost	897		762
Held to maturity, gross unrealized gains	2		1
Held to maturity, gross unrealized losses	0		0
Held to maturity, fair value	899		763
Asset-backed securities, sub-prime	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	1,054		1,291
Available for sale, gross unrealized gains	2		3
Available for sale, gross unrealized losses	59		91
Available for sale, fair value	997		1,203
Asset-backed securities, other	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	4,239		4,949
Available for sale, gross unrealized gains	114		138
Available for sale, gross unrealized losses	10		23
Available for sale, fair value	4,343		5,064
Held to maturity, amortized cost	633		782
Held to maturity, gross unrealized gains	3		1
Held to maturity, gross unrealized losses	1		2
Held to maturity, fair value	635		781
Total non-U.S. debt securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	22,896		24,615
Available for sale, gross unrealized gains	263		314
Available for sale, gross unrealized losses	11		22
Available for sale, fair value	23,148		24,907
Held to maturity, amortized cost	7,631		6,607
Held to maturity, gross unrealized gains	210		169
Held to maturity, gross unrealized losses	16		48
Held to maturity, fair value	7,825		6,728
Non-U.S. debt securities, mortgage-backed securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	10,056		10,808
Available for sale, gross unrealized gains	185		230
Available for sale, gross unrealized losses	2		9
Available for sale, fair value	10,239		11,029
Held to maturity, amortized cost	4,153		4,211
Held to maturity, gross unrealized gains	192		150
Held to maturity, gross unrealized losses	16		48
Held to maturity, fair value	4,329		4,313
Non-U.S. debt securities, asset-backed securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	3,433		5,369
Available for sale, gross unrealized gains	15		23
Available for sale, gross unrealized losses	1		2
Available for sale, fair value	3,447		5,390
Held to maturity, amortized cost	3,293		2,202
Held to maturity, gross unrealized gains	18		19
Held to maturity, gross unrealized losses	0		0
Held to maturity, fair value	3,311		2,221
Non-US debt securities, government securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	3,605		3,759
Available for sale, gross unrealized gains	8		2
Available for sale, gross unrealized losses	0		0
Available for sale, fair value	3,613		3,761
Held to maturity, amortized cost	110		2
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	0		0
Held to maturity, fair value	110		2
Non-U.S. debt securities, other	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	5,802		4,679
Available for sale, gross unrealized gains	55		59
Available for sale, gross unrealized losses	8		11
Available for sale, fair value	5,849		4,727
Held to maturity, amortized cost	75		192
Held to maturity, gross unrealized gains	0		0
Held to maturity, gross unrealized losses	0		0
Held to maturity, fair value	75		192
State and political subdivisions	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	10,366		10,301
Available for sale, gross unrealized gains	323		160
Available for sale, gross unrealized losses	44		198
Available for sale, fair value	10,645		10,263
Held to maturity, amortized cost	12		24
Held to maturity, gross unrealized gains	0		1
Held to maturity, gross unrealized losses	0		0
Held to maturity, fair value	12		25
Collateralized mortgage obligations	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	4,629		5,275
Available for sale, gross unrealized gains	57		70
Available for sale, gross unrealized losses	15		76
Available for sale, fair value	4,671		5,269
Held to maturity, amortized cost	2,536		2,806
Held to maturity, gross unrealized gains	129		176
Held to maturity, gross unrealized losses	15		26
Held to maturity, fair value	2,650		2,956
Other U.S. debt securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	4,189		4,876
Available for sale, gross unrealized gains	106		138
Available for sale, gross unrealized losses	11		34
Available for sale, fair value	4,284		4,980
U.S. equity securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	29		28
Available for sale, gross unrealized gains	9		6
Available for sale, gross unrealized losses	0		0
Available for sale, fair value	38		34
Non-U.S. equity securities	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	2		1
Available for sale, gross unrealized gains	0		0
Available for sale, gross unrealized losses	0		0
Available for sale, fair value	2		1
U.S. money-market mutual funds	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	532		422
Available for sale, gross unrealized gains	0		0
Available for sale, gross unrealized losses	0		0
Available for sale, fair value	532		422
Non-U.S. money-market mutual funds	'		'
Available-For-Sale and Held-To-Maturity-Securities [Line Items]	'		'
Available for sale, amortized cost	10		7
Available for sale, gross unrealized gains	0		0
Available for sale, gross unrealized losses	0		0
Available for sale, fair value	$10		$7
[1]	Substantially composed of securities guaranteed by the federal government with respect to at least 97% of defaulted principal and accrued interest on the underlying loans.

Investment_Securities_Schedule1

Investment Securities (Schedule of Gross Pre-Tax Unrealized Losses on Investment Securities) (Details) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	$12,914	$27,220
Available for sale, Gross Unrealized Losses Less than 12 months	42	580
Available for sale, Fair Value 12 months or longer	18,979	13,764
Available for sale, Gross Unrealized Losses 12 months or longer	462	567
Available for sale, Fair Value Total	31,893	40,984
Available for sale, Gross Unrealized Losses Total	504	1,147
Held to maturity, Fair Value Less than 12 months	1,279	7,813
Held to maturity, Gross Unrealized Losses Less than 12 months	7	480
Held to maturity, Fair Value 12 months or longer	5,991	1,068
Held to maturity, Gross Unrealized Losses 12 months or longer	248	54
Held to maturity, Fair Value Total	7,270	8,881
Held to maturity, Gross Unrealized Losses Total	255	534
Asset-backed securities	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	897	7,540
Available for sale, Gross Unrealized Losses Less than 12 months	4	58
Available for sale, Fair Value 12 months or longer	8,858	9,002
Available for sale, Gross Unrealized Losses 12 months or longer	217	365
Available for sale, Fair Value Total	9,755	16,542
Available for sale, Gross Unrealized Losses Total	221	423
Held to maturity, Fair Value Less than 12 months	443	1,649
Held to maturity, Gross Unrealized Losses Less than 12 months	2	11
Held to maturity, Fair Value 12 months or longer	0	29
Held to maturity, Gross Unrealized Losses 12 months or longer	0	1
Held to maturity, Fair Value Total	443	1,678
Held to maturity, Gross Unrealized Losses Total	2	12
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	4,374	182
Available for sale, Gross Unrealized Losses Less than 12 months	3	1
Available for sale, Fair Value 12 months or longer	158	113
Available for sale, Gross Unrealized Losses 12 months or longer	1	1
Available for sale, Fair Value Total	4,532	295
Available for sale, Gross Unrealized Losses Total	4	2
Held to maturity, Fair Value Less than 12 months	114	4,571
Held to maturity, Gross Unrealized Losses Less than 12 months	1	448
Held to maturity, Fair Value 12 months or longer	4,781	0
Held to maturity, Gross Unrealized Losses 12 months or longer	221	0
Held to maturity, Fair Value Total	4,895	4,571
Held to maturity, Gross Unrealized Losses Total	222	448
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	3,391	10,562
Available for sale, Gross Unrealized Losses Less than 12 months	23	316
Available for sale, Fair Value 12 months or longer	7,026	2,389
Available for sale, Gross Unrealized Losses 12 months or longer	175	76
Available for sale, Fair Value Total	10,417	12,951
Available for sale, Gross Unrealized Losses Total	198	392
Asset-backed securities, student loans	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	291	1,930
Available for sale, Gross Unrealized Losses Less than 12 months	2	16
Available for sale, Fair Value 12 months or longer	6,158	7,252
Available for sale, Gross Unrealized Losses 12 months or longer	120	252
Available for sale, Fair Value Total	6,449	9,182
Available for sale, Gross Unrealized Losses Total	122	268
Held to maturity, Fair Value Less than 12 months	364	1,352
Held to maturity, Gross Unrealized Losses Less than 12 months	1	10
Held to maturity, Fair Value 12 months or longer	0	0
Held to maturity, Gross Unrealized Losses 12 months or longer	0	0
Held to maturity, Fair Value Total	364	1,352
Held to maturity, Gross Unrealized Losses Total	1	10
Asset-backed securities, credit cards	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	0	3,714
Available for sale, Gross Unrealized Losses Less than 12 months	0	30
Available for sale, Fair Value 12 months or longer	1,258	161
Available for sale, Gross Unrealized Losses 12 months or longer	30	11
Available for sale, Fair Value Total	1,258	3,875
Available for sale, Gross Unrealized Losses Total	30	41
Held to maturity, Fair Value Less than 12 months	'	297
Held to maturity, Gross Unrealized Losses Less than 12 months	'	1
Held to maturity, Fair Value 12 months or longer	'	29
Held to maturity, Gross Unrealized Losses 12 months or longer	'	1
Held to maturity, Fair Value Total	'	326
Held to maturity, Gross Unrealized Losses Total	'	2
Asset-backed securities, sub-prime	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	0	0
Available for sale, Gross Unrealized Losses Less than 12 months	0	0
Available for sale, Fair Value 12 months or longer	936	1,150
Available for sale, Gross Unrealized Losses 12 months or longer	59	91
Available for sale, Fair Value Total	936	1,150
Available for sale, Gross Unrealized Losses Total	59	91
Asset-backed securities, other	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	606	1,896
Available for sale, Gross Unrealized Losses Less than 12 months	2	12
Available for sale, Fair Value 12 months or longer	506	439
Available for sale, Gross Unrealized Losses 12 months or longer	8	11
Available for sale, Fair Value Total	1,112	2,335
Available for sale, Gross Unrealized Losses Total	10	23
Held to maturity, Fair Value Less than 12 months	79	'
Held to maturity, Gross Unrealized Losses Less than 12 months	1	'
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	79	'
Held to maturity, Gross Unrealized Losses Total	1	'
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	2,591	3,074
Available for sale, Gross Unrealized Losses Less than 12 months	3	12
Available for sale, Fair Value 12 months or longer	543	424
Available for sale, Gross Unrealized Losses 12 months or longer	8	10
Available for sale, Fair Value Total	3,134	3,498
Available for sale, Gross Unrealized Losses Total	11	22
Held to maturity, Fair Value Less than 12 months	255	834
Held to maturity, Gross Unrealized Losses Less than 12 months	1	3
Held to maturity, Fair Value 12 months or longer	658	878
Held to maturity, Gross Unrealized Losses 12 months or longer	15	45
Held to maturity, Fair Value Total	913	1,712
Held to maturity, Gross Unrealized Losses Total	16	48
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	443	868
Available for sale, Gross Unrealized Losses Less than 12 months	1	2
Available for sale, Fair Value 12 months or longer	176	258
Available for sale, Gross Unrealized Losses 12 months or longer	1	7
Available for sale, Fair Value Total	619	1,126
Available for sale, Gross Unrealized Losses Total	2	9
Held to maturity, Fair Value Less than 12 months	255	'
Held to maturity, Gross Unrealized Losses Less than 12 months	1	'
Held to maturity, Fair Value 12 months or longer	658	'
Held to maturity, Gross Unrealized Losses 12 months or longer	15	'
Held to maturity, Fair Value Total	913	'
Held to maturity, Gross Unrealized Losses Total	16	'
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	0	551
Available for sale, Gross Unrealized Losses Less than 12 months	0	1
Available for sale, Fair Value 12 months or longer	84	16
Available for sale, Gross Unrealized Losses 12 months or longer	1	1
Available for sale, Fair Value Total	84	567
Available for sale, Gross Unrealized Losses Total	1	2
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	2,148	1,655
Available for sale, Gross Unrealized Losses Less than 12 months	2	9
Available for sale, Fair Value 12 months or longer	283	150
Available for sale, Gross Unrealized Losses 12 months or longer	6	2
Available for sale, Fair Value Total	2,431	1,805
Available for sale, Gross Unrealized Losses Total	8	11
State and political subdivisions	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	439	3,242
Available for sale, Gross Unrealized Losses Less than 12 months	2	113
Available for sale, Fair Value 12 months or longer	1,786	1,268
Available for sale, Gross Unrealized Losses 12 months or longer	42	85
Available for sale, Fair Value Total	2,225	4,510
Available for sale, Gross Unrealized Losses Total	44	198
Collateralized mortgage obligations	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	886	1,581
Available for sale, Gross Unrealized Losses Less than 12 months	5	55
Available for sale, Fair Value 12 months or longer	314	510
Available for sale, Gross Unrealized Losses 12 months or longer	10	21
Available for sale, Fair Value Total	1,200	2,091
Available for sale, Gross Unrealized Losses Total	15	76
Held to maturity, Fair Value Less than 12 months	467	759
Held to maturity, Gross Unrealized Losses Less than 12 months	3	18
Held to maturity, Fair Value 12 months or longer	552	161
Held to maturity, Gross Unrealized Losses 12 months or longer	12	8
Held to maturity, Fair Value Total	1,019	920
Held to maturity, Gross Unrealized Losses Total	15	26
Other U.S. debt securities	'	'
Gross Pre-Tax Unrealized Losses On Investment Securities [Line Items]	'	'
Available for sale, Fair Value Less than 12 months	336	1,039
Available for sale, Gross Unrealized Losses Less than 12 months	2	25
Available for sale, Fair Value 12 months or longer	294	58
Available for sale, Gross Unrealized Losses 12 months or longer	9	9
Available for sale, Fair Value Total	630	1,097
Available for sale, Gross Unrealized Losses Total	$11	$34

Investment_Securities_Schedule2

Investment Securities (Schedule of Contractual Maturities of Debt Securities) (Details) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	$9,460
Available for sale, 1 to 5 Years	37,394
Available for sale, 6 to 10 Years	21,706
Available for sale, Over 10 Years	27,410
Held to maturity, Under 1 Year	1,050
Held to maturity, 1 to 5 Years	5,860
Held to maturity, 6 to 10 Years	7,150
Held to maturity, Over 10 Years	4,707
Total asset-backed securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	913
Available for sale, 1 to 5 Years	9,168
Available for sale, 6 to 10 Years	6,190
Available for sale, Over 10 Years	4,986
Held to maturity, Under 1 Year	26
Held to maturity, 1 to 5 Years	958
Held to maturity, 6 to 10 Years	1,123
Held to maturity, Over 10 Years	1,296
US Treasury and federal agencies, direct obligations	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	151
Available for sale, 1 to 5 Years	6,766
Available for sale, 6 to 10 Years	3,300
Available for sale, Over 10 Years	547
Held to maturity, Under 1 Year	0
Held to maturity, 1 to 5 Years	0
Held to maturity, 6 to 10 Years	5,000
Held to maturity, Over 10 Years	117
US Treasury and federal agencies, mortgage-backed securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	183
Available for sale, 1 to 5 Years	2,441
Available for sale, 6 to 10 Years	4,753
Available for sale, Over 10 Years	13,824
Held to maturity, Under 1 Year	0
Held to maturity, 1 to 5 Years	15
Held to maturity, 6 to 10 Years	13
Held to maturity, Over 10 Years	40
Asset-backed securities, student loans	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	342
Available for sale, 1 to 5 Years	6,572
Available for sale, 6 to 10 Years	3,750
Available for sale, Over 10 Years	2,142
Held to maturity, Under 1 Year	7
Held to maturity, 1 to 5 Years	182
Held to maturity, 6 to 10 Years	393
Held to maturity, Over 10 Years	1,291
Asset-backed securities, credit cards	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	307
Available for sale, 1 to 5 Years	1,513
Available for sale, 6 to 10 Years	1,291
Available for sale, Over 10 Years	0
Held to maturity, Under 1 Year	0
Held to maturity, 1 to 5 Years	375
Held to maturity, 6 to 10 Years	522
Held to maturity, Over 10 Years	0
Asset-backed securities, sub-prime	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	9
Available for sale, 1 to 5 Years	14
Available for sale, 6 to 10 Years	0
Available for sale, Over 10 Years	974
Asset-backed securities, other	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	255
Available for sale, 1 to 5 Years	1,069
Available for sale, 6 to 10 Years	1,149
Available for sale, Over 10 Years	1,870
Held to maturity, Under 1 Year	19
Held to maturity, 1 to 5 Years	401
Held to maturity, 6 to 10 Years	208
Held to maturity, Over 10 Years	5
Total non-U.S. debt securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	6,496
Available for sale, 1 to 5 Years	11,612
Available for sale, 6 to 10 Years	1,612
Available for sale, Over 10 Years	3,428
Held to maturity, Under 1 Year	438
Held to maturity, 1 to 5 Years	4,334
Held to maturity, 6 to 10 Years	511
Held to maturity, Over 10 Years	2,348
Non-U.S. debt securities, mortgage-backed securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	2,190
Available for sale, 1 to 5 Years	4,344
Available for sale, 6 to 10 Years	384
Available for sale, Over 10 Years	3,321
Held to maturity, Under 1 Year	323
Held to maturity, 1 to 5 Years	1,208
Held to maturity, 6 to 10 Years	274
Held to maturity, Over 10 Years	2,348
Non-U.S. debt securities, asset-backed securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	359
Available for sale, 1 to 5 Years	2,691
Available for sale, 6 to 10 Years	290
Available for sale, Over 10 Years	107
Held to maturity, Under 1 Year	5
Held to maturity, 1 to 5 Years	3,051
Held to maturity, 6 to 10 Years	237
Held to maturity, Over 10 Years	0
Non-US debt securities, government securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	1,978
Available for sale, 1 to 5 Years	1,635
Available for sale, 6 to 10 Years	0
Available for sale, Over 10 Years	0
Held to maturity, Under 1 Year	110
Held to maturity, 1 to 5 Years	0
Held to maturity, 6 to 10 Years	0
Held to maturity, Over 10 Years	0
Non-U.S. debt securities, other	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	1,969
Available for sale, 1 to 5 Years	2,942
Available for sale, 6 to 10 Years	938
Available for sale, Over 10 Years	0
Held to maturity, Under 1 Year	0
Held to maturity, 1 to 5 Years	75
Held to maturity, 6 to 10 Years	0
Held to maturity, Over 10 Years	0
State and political subdivisions	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	731
Available for sale, 1 to 5 Years	3,021
Available for sale, 6 to 10 Years	4,451
Available for sale, Over 10 Years	2,442
Held to maturity, Under 1 Year	9
Held to maturity, 1 to 5 Years	3
Held to maturity, 6 to 10 Years	0
Held to maturity, Over 10 Years	0
Collateralized mortgage obligations	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	286
Available for sale, 1 to 5 Years	1,165
Available for sale, 6 to 10 Years	1,072
Available for sale, Over 10 Years	2,148
Held to maturity, Under 1 Year	577
Held to maturity, 1 to 5 Years	550
Held to maturity, 6 to 10 Years	503
Held to maturity, Over 10 Years	906
Other U.S. debt securities	'
Contractual Maturities Of Debt Investment Securities [Line Items]	'
Available for sale, Under 1 Year	700
Available for sale, 1 to 5 Years	3,221
Available for sale, 6 to 10 Years	328
Available for sale, Over 10 Years	$35

Investment_Securities_Gains_an

Investment Securities (Gains and Losses Related to Investment Securities) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'	'	'	'
Gross realized gains from sales of available-for-sale securities	$48	$11	$64	$98
Gross realized losses from sales of available-for-sale securities	-48	-5	-49	-87
Gross losses from other-than-temporary impairment	0	-13	-1	-19
Losses reclassified (from) to other comprehensive income	0	3	-10	-1
Gains (losses) related to investment securities, net	0	-4	4	-9
Impairment associated with expected credit losses	0	-8	-10	-8
Impairment Associated With Management's Intent To Sell The Impaired Securities Prior To Their Recovery In Value	0	0	0	6
Impairment associated with adverse changes in timing of expected future cash flows	0	-2	-1	-6
Net impairment losses	$0	($10)	($11)	($20)

Investment_Securities_Schedule3

Investment Securities (Schedule of Credit-Related Loss Activity Recognized In Earnings) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]	'	'
Beginning balance	$122	$124
Plus losses for which other-than-temporary impairment was not previously recognized	0	14
Plus losses for which other-than-temporary impairment was previously recognized	11	6
Less previously recognized losses related to securities sold or matured	-11	-10
Less losses related to securities intended or required to be sold	-6	0
Ending balance	$116	$134

Loans_and_Leases_Narrative_Det

Loans and Leases (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
			loan		loan
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Allowance for Loan and Lease Losses, Write-offs	$0	$0	$0	$0	'
Loans and leases, allowance for losses	34,000,000	'	34,000,000	'	28,000,000
Aggregate short-duration advances	5,390,000,000	'	5,390,000,000	'	2,450,000,000
Loans modified in troubled debt restructurings	'	'	0	'	0
Provisions	2,000,000	0	6,000,000	0	'
Senior Secured Bank Loans	'	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Provisions	16,000,000	'	'	'	'
Institutional	'	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Allowance for Loan and Lease Losses, Write-offs	0	0	0	0	'
Amount of loan losses related to institutional loans collectively evaluated for impairment	34,000,000	'	34,000,000	'	28,000,000
Provisions	0	0	0	0	'
Institutional | Senior Secured Bank Loans	'	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Commercial and financial	1,720,000,000	'	1,720,000,000	'	724,000,000
Commercial and Financial	'	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Loans and leases, allowance for losses	12,000,000	'	12,000,000	'	'
Adjustment to Provision for Loans and Lease Losses	10,000,000	'	'	'	'
Commercial and Financial | Senior Secured Bank Loans	'	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Loans and leases, allowance for losses	22,000,000	'	22,000,000	'	'
Commercial Real Estate	'	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'	'
Allowance for Loan and Lease Losses, Write-offs	0	0	0	0	'
Amount of loan losses related to institutional loans collectively evaluated for impairment	'	'	'	'	28,000,000
Loan modification, recorded investment	130,000,000	'	130,000,000	'	130,000,000
Impairment loss recognized	'	'	'	'	0
Provisions	$0	$0	$0	$0	'

Loans_and_Leases_Net_Loans_Det

Loans and Leases (Net Loans) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total loans and leases	$18,398	$13,486
Allowance for loan losses	-34	-28
Loans and leases, net of allowance for loan losses	18,364	13,458
Institutional	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total loans and leases	18,102	13,277
Commercial Real Estate	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Total loans and leases	296	209
U.S. | Institutional	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Investment funds	10,896	8,695
Commercial and financial	2,506	1,372
Purchased receivables	142	217
Lease financing	340	339
U.S. | Commercial Real Estate	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Commercial real estate	296	209
Non-U.S. | Institutional	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Investment funds	3,250	1,718
Commercial and financial	240	154
Purchased receivables	0	26
Lease financing	$728	$756

Loans_and_Leases_Recorded_Inve

Loans and Leases (Recorded Investment in Each Class of Total Loans and Leases by Credit Quality Indicator) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	$18,398		$13,486
Investment Funds	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	14,146		10,413
Commercial and Financial	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	2,746		1,526
Purchased Receivables	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	142		243
Lease Financing	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	1,068		1,095
Property Development	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	268		180
Other	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	28		29
Investment grade	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	15,984	[1]	12,362	[1]
Investment grade | Investment Funds	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	13,864	[1]	10,282	[1]
Investment grade | Commercial and Financial	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	916	[1]	740	[1]
Investment grade | Purchased Receivables	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	142	[1]	243	[1]
Investment grade | Lease Financing	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	1,034	[1]	1,068	[1]
Investment grade | Property Development	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	0	[1]	0	[1]
Investment grade | Other	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	28	[1]	29	[1]
Speculative	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	2,414	[2]	1,108	[2]
Speculative | Investment Funds	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	282	[2]	131	[2]
Speculative | Commercial and Financial	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	1,830	[2]	770	[2]
Speculative | Purchased Receivables	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	0	[2]	0	[2]
Speculative | Lease Financing	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	34	[2]	27	[2]
Speculative | Property Development	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	268	[2]	180	[2]
Speculative | Other	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	0	[2]	0	[2]
Special mention	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		16	[3]
Special mention | Investment Funds	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		0	[3]
Special mention | Commercial and Financial	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		16	[3]
Special mention | Purchased Receivables	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		0	[3]
Special mention | Lease Financing	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		0	[3]
Special mention | Property Development	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		0	[3]
Special mention | Other	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Total Loans and Leases	'		$0	[3]
[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.

Loans_and_Leases_Schedule_of_A

Loans and Leases (Schedule of Allowance for Loan Losses) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Loans and leases, Individually evaluated for impairment	$130		$206
Loans and leases, Collectively evaluated for impairment	18,268	[1]	13,280	[1]
Total loans and leases	18,398		13,486
Institutional	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Loans and leases, Individually evaluated for impairment	0		26
Loans and leases, Collectively evaluated for impairment	18,102	[1]	13,251	[1]
Total loans and leases	18,102		13,277
Commercial Real Estate	'		'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'		'
Loans and leases, Individually evaluated for impairment	130		180
Loans and leases, Collectively evaluated for impairment	166	[1]	29	[1]
Total loans and leases	$296		$209
[1]	As of September 30, 2014 and December 31, 2013, all of the allowance for loan losses of $34 million and $28 million, respectively, related to institutional loans collectively evaluated for impairment.

Loans_and_Leases_Impaired_Loan

Loans and Leases (Impaired Loans) (Details) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
CRE - property development	'		'	'		'	'
Financing Receivable, Impaired [Line Items]	'		'	'		'	'
Recorded investment with no related allowance	$130		'	$130		'	$130
Unpaid principal balance with no related allowance recorded	143		'	143		'	143
Related allowance	0	[1]	'	0	[1]	'	0	[1]
Average recorded investment	130		130	130		160	'
Interest revenue with related allowance recognized	3		2	8		17	'
CRE - property development - acquired credit impaired	'		'	'		'	'
Financing Receivable, Impaired [Line Items]	'		'	'		'	'
Recorded investment with no related allowance	0		'	0		'	0
Unpaid principal balance with no related allowance recorded	34		'	34		'	34
Related allowance	0	[1]	'	0	[1]	'	0	[1]
CRE - other - acquired credit impaired	'		'	'		'	'
Financing Receivable, Impaired [Line Items]	'		'	'		'	'
Recorded investment with no related allowance	0		'	0		'	0
Unpaid principal balance with no related allowance recorded	22		'	22		'	21
Related allowance	0	[1]	'	0	[1]	'	0	[1]
Commercial Real Estate	'		'	'		'	'
Financing Receivable, Impaired [Line Items]	'		'	'		'	'
Recorded investment with no related allowance	130		'	130		'	130
Unpaid principal balance with no related allowance recorded	199		'	199		'	198
Related allowance	0	[1]	'	0	[1]	'	0	[1]
Average recorded investment	130		130	130		160	'
Interest revenue recognized	$3		$2	$8		$17	'
[1]	As of September 30, 2014 and December 31, 2013, all of the allowance for loan losses of $34 million and $28 million, respectively, related to loans that were not impaired. Three Months Ended September 30, Average Recorded Investment Interest Revenue Recognized 2014 2013 2014 2013(In millions) With no related allowance recorded: CRE—property development$130 $130 $3 $2Total CRE$130 $130 $3 $2

Loans_and_Leases_Schedule_of_A1

Loans and Leases (Schedule of Activity In The Allowance For Loan Losses) (Details) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013
Allowance for Loan and Lease Losses [Roll Forward]	'		'	'		'
Beginning balance	$32		$22	$28		$22
Allowance for Loan and Lease Losses, Write-offs	0		0	0		0
Provisions	2		0	6		0
Financing Receivable, Allowance for Credit Losses, Recovery	0		0	0		0
Ending balance	34	[1]	22	34	[1]	22
Institutional	'		'	'		'
Allowance for Loan and Lease Losses [Roll Forward]	'		'	'		'
Beginning balance	32		22	28		22
Allowance for Loan and Lease Losses, Write-offs	0		0	0		0
Provisions	0		0	0		0
Financing Receivable, Allowance for Credit Losses, Recovery	2		0	6		0
Ending balance	34	[1]	22	34	[1]	22
Commercial Real Estate	'		'	'		'
Allowance for Loan and Lease Losses [Roll Forward]	'		'	'		'
Beginning balance	0		0	0		0
Allowance for Loan and Lease Losses, Write-offs	0		0	0		0
Provisions	0		0	0		0
Financing Receivable, Allowance for Credit Losses, Recovery	0		0	0		0
Ending balance	$0	[1]	$0	$0	[1]	$0
[1]	As of September 30, 2014, approximately $22 million of our allowance for loan losses was related to senior secured bank loans included in the institutional segment; the remaining $12 million was related to other commercial-and-financial loans in the institutional segment.

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Changes In The Carrying Amount Of Goodwill) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Goodwill [Roll Forward]	'	'
Beginning balance	$6,036	$5,977
Foreign currency translation and other, net	-137	29
Ending balance	5,899	6,006
Investment Servicing	'	'
Goodwill [Roll Forward]	'	'
Beginning balance	5,999	5,941
Foreign currency translation and other, net	-134	28
Ending balance	5,865	5,969
Investment Management	'	'
Goodwill [Roll Forward]	'	'
Beginning balance	37	36
Foreign currency translation and other, net	-3	1
Ending balance	$34	$37

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Changes In The Carrying Amount Of Other Intangible Assets) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Finite-lived Intangible Assets [Roll Forward]	'	'	'	'
Beginning balance	'	'	$2,360	$2,539
Amortization	-54	-53	-162	-160
Foreign currency translation and other, net	'	'	-77	17
Ending balance	2,121	2,396	2,121	2,396
Investment Servicing	'	'	'	'
Finite-lived Intangible Assets [Roll Forward]	'	'	'	'
Beginning balance	'	'	2,321	2,492
Amortization	'	'	-155	-153
Foreign currency translation and other, net	'	'	-75	17
Ending balance	2,091	2,356	2,091	2,356
Investment Management	'	'	'	'
Finite-lived Intangible Assets [Roll Forward]	'	'	'	'
Beginning balance	'	'	39	47
Amortization	'	'	-7	-7
Foreign currency translation and other, net	'	'	-2	0
Ending balance	$30	$40	$30	$40

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets (Gross Carrying Amount, Accumulated Amortization And Net Carrying Amount Of Other Intangible Assets) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Gross Carrying Amount	$3,531	$3,657	'	'
Accumulated Amortization	-1,410	-1,297	'	'
Net Carrying Amount	2,121	2,360	2,396	2,539
Client relationships	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Gross Carrying Amount	2,614	2,706	'	'
Accumulated Amortization	-1,060	-975	'	'
Net Carrying Amount	1,554	1,731	'	'
Core deposits	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Gross Carrying Amount	697	717	'	'
Accumulated Amortization	-213	-191	'	'
Net Carrying Amount	484	526	'	'
Other	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Gross Carrying Amount	220	234	'	'
Accumulated Amortization	-137	-131	'	'
Net Carrying Amount	$83	$103	'	'

Other_Assets_Components_of_Oth

Other Assets (Components of Other Assets) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Other Assets [Line Items]	'		'
Total	$34,145		$25,990
Real estate acquired through foreclosure	61		59
Reported Amount | Other assets	'		'
Other Assets [Line Items]	'		'
Collateral deposits, net	17,540		13,706
Unrealized gains on derivative financial instruments, net	8,712		5,476
Bank-owned life insurance	2,391		2,343
Investments in joint ventures and other unconsolidated entities	1,741		1,644
Receivable for securities sold	917		0
Accounts receivable	843		950
Receivable for securities settlement	396		195
Prepaid expenses	307		286
Income taxes receivable	258		337
Deferred tax assets, net of valuation allowance	253		263
Deposits with clearing organizations	231		177
Other	556	[1]	613	[1]
Total	$34,145		$25,990
[1]	Included other real estate owned of approximately $61 million and $59 million as of September 30, 2014 and December 31, 2013, respectively.

Contingencies_Narrative_Detail

Contingencies (Narrative) (Details)

Sep. 30, 2014

Dec. 31, 2013

Aug. 31, 2009

Jan. 31, 2014

Sep. 30, 2014

Sep. 30, 2014

Jan. 31, 2014

Jan. 31, 2014

Aug. 31, 2009

Sep. 30, 2014

Jun. 30, 2013

Oct. 31, 2009

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

In Millions, unless otherwise specified

USD ($)

USD ($)

customer

Transition Management

Transition Management

Transition Management

Transition Management

Transition Management

Securities Finance

Securities Finance

Securities Finance

Foreign Exchange

Foreign Exchange

Foreign Exchange

Foreign Exchange

Foreign Exchange

Foreign Exchange

Foreign Exchange

Foreign Exchange

Putative Class Action

Shareholder Litigation

Salary Savings Program

Investment Servicing

claim

USD ($)

Legal Reserve

Regulatory Matter

Regulatory Matter

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

claim

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

GBP (£)

complaint

claim

shareholder

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss Contingency, Estimate of Possible Loss

'

'

'

'

'

'

'

'

'

'

'

'

$70

'

'

'

'

'

'

'

'

'

'

Loss Contingency, Estimate Of Possible Loss, net of tax

'

'

'

'

'

'

'

'

'

'

'

'

53

'

'

'

'

'

'

'

'

'

'

Legal reserves

'

'

'

'

'

111

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of pending claims

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

1

Settlement, amount

'

'

'

'

'

'

37.8

22.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Litigation reserve

'

'

'

'

4.3

'

'

'

'

10

'

'

'

'

'

'

'

'

'

'

'

'

4.3

Number of suits from related participants of agency securities lending program

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss contingency, damages sought, value

'

'

'

'

'

'

'

'

125

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Realized loss on sales of securities

'

'

'

'

'

'

'

'

'

'

11

'

'

'

'

'

'

'

'

'

'

'

'

Actual damages asserted by attorney general

'

'

'

'

'

'

'

'

'

'

'

100

'

'

'

'

'

'

'

'

'

'

'

Estimated indirect foreign exchange revenue

'

'

'

'

'

'

'

'

'

'

'

'

186

285

248

331

336

369

462

'

'

'

'

Shareholder related class action complaints pending in Boston Federal Court

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3

'

'

Number of class action complaints pending in Boston Federal Court brought on behalf of State Street shareholders

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

Number of class action complaints pending in Boston Federal Court brought on behalf of State Street participants and beneficiaries of State Street Salary Savings Program

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

Settlement Liabilities, Current

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

60

10

'

Claims settled

'

'

'

6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecognized tax benefits

$155

$164

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Guarantees_Con

Commitments and Guarantees Contingencies (Details) (USD $)	9 Months Ended
In Billions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]	'	'
Unfunded commitments to extend credit	$24.15	$21.30
Unfunded commitments to extend credit, short term	78.00%	'
Unfunded Commitment to Extend Credit, Term	'1 year	'
Percent of fair market value that must be maintained in collateral	100.00%	'
Cash collateral provided for securities lending	15.78	11.29
Accrued expenses and other liabilities	'	'
Loss Contingencies [Line Items]	'	'
Cash collateral received in connection to securities finance activities	$7.01	$6.62

Commitments_and_Guarantees_Con1

Commitments and Guarantees (Contractual Amounts of Credit-Related Off-Balance Sheet Financial Instruments) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'	'
Indemnified securities financing	$340,239	$320,078
Stable value protection	24,305	24,906
Asset purchase agreements	4,205	4,685
Standby letters of credit	$4,455	$4,612

Commitments_and_Guarantees_Sch

Commitments and Guarantees (Schedule Of Repurchase Agreements) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'	'
Aggregate fair value of indemnified securities financing	$340,239	$320,078
Aggregate fair value of cash and securities held by us, as agent, as collateral for indemnified securities financing	354,516	331,732
Aggregate fair value of collateral for indemnified securities financing invested in indemnified repurchase agreements	81,870	85,374
Aggregate fair value of cash and securities held by us or our agents as collateral for investments in indemnified repurchase agreements	$87,191	$91,097

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Variable Interest Entities [Abstract]	'	'
Investment securities related to state and political subdivisions	$2,300,000,000	$2,330,000,000
Variable interest entity, other short-term borrowings	1,890,000,000	1,950,000,000
Weighted average life of trusts (in years)	'6 years 1 month	'6 years 6 months
Total standby bond-purchase agreement committed to trusts	1,920,000,000	'
Total letters of credit committed to trusts	684,000,000	'
Standby purchase agreements and letters of credit commitments utilized	0	'
Variable Interest Entity, Primary Beneficiary	'	'
Variable Interest Entity [Line Items]	'	'
Assets	313,000,000	50,000,000
Liabilities	260,000,000	'
Potential maximum loss exposure of unconsolidated funds	53,000,000	'
Variable Interest Entity, Not Primary Beneficiary	'	'
Variable Interest Entity [Line Items]	'	'
Potential maximum loss exposure of unconsolidated funds	$40,000,000	$18,000,000

Shareholders_Equity_Narrative_

Shareholders' Equity (Narrative) (Details) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Mar. 31, 2013

Sep. 30, 2014

Mar. 31, 2014

Sep. 30, 2014

Mar. 31, 2014

Mar. 31, 2014

Sep. 30, 2014

Mar. 31, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Mar. 31, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

March 2014 Repurchase Program

March 2014 Repurchase Program

March 2014 Repurchase Program

March 2014 Repurchase Program

March 2013 Repurchase Program

Depositary Shares

Series C Preferred Stock

Series C Preferred Stock

Series C Preferred Stock

Series C Preferred Stock

Series C Preferred Stock

Series C Preferred Stock, Depository Share

Series C Preferred Stock, Depository Share

Series C Preferred Stock, Depository Share

Series C Preferred Stock, Depository Share

Retained Earnings

Retained Earnings

Retained Earnings

Retained Earnings

Series D Preferred Stock

Series D Preferred Stock

Series D Preferred Stock

Series D Preferred Stock, Depository Share

Series D Preferred Stock, Depository Share

Equity, Class of Treasury Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock issued during period

'

'

'

'

'

'

'

'

'

'

'

30,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Depositary shares, ownership interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.03%

'

'

'

'

'

'

'

'

'

'

'

0.03%

'

'

Liquidation preference (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

$25

'

$100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from issuance of preferred stock

'

'

$742,000,000

$0

'

'

'

'

'

'

'

$742,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock dividends (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

$1,313

'

$1,313

$3,939

$3,939

$0.33

$0.33

$0.99

$0.98

'

'

'

'

$1,475

'

$3,130

$0.37

$0.78

Preferred stock cash dividend

'

'

-43,000,000

-20,000,000

'

'

'

'

'

'

'

'

-7,000,000

'

-7,000,000

-20,000,000

-20,000,000

'

'

'

'

'

'

'

'

-11,000,000

'

-23,000,000

'

'

Dividend rate

'

'

'

'

'

'

'

'

'

'

'

'

'

5.25%

'

'

'

'

'

'

'

'

'

'

'

'

5.90%

'

'

'

Redemption price (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

$25

'

$100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount of common stock authorized for repurchase

'

'

'

'

'

'

1,700,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash dividends declared (in dollars per share)

$0.30

$0.26

$0.86

$0.78

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock dividends

'

'

366,000,000

350,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

126,000,000

115,000,000

366,000,000

350,000,000

'

'

'

'

'

Net gains (losses) from sales of available-for-sale securities

'

'

-15,000,000

-11,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net after tax realized gains (losses) on AFS securities

-9,000,000

7,000,000

-9,000,000

7,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrealized pretax gains (losses) on securities included in AOCI

'

'

'

'

-43,000,000

25,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred taxes on unrealized pretax gains (losses) on securities included in AOCI

'

'

'

'

-17,000,000

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock acquired (shares)

'

'

18,200,000

'

'

'

'

5,800,000

0

12,100,000

6,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Treasury Stock Acquired, Average Cost Per Share

'

'

$68.18

'

'

'

'

$70.61

'

$67.70

$69.14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock Repurchased During Period, Value

'

'

$1,240,000,000

'

'

'

'

$410,000,000

'

$820,000,000

$420,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares available for purchase

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shareholders_Equity_Schedule_O

Shareholders' Equity (Schedule Of Accumulated Other Comprehensive (Loss) Income) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Stockholders' Equity Note [Abstract]	'	'
Net unrealized gains on cash flow hedges	$217	$161
Net unrealized gains (losses) on available-for-sale securities portfolio	254	-56
Net unrealized gains (losses) related to reclassified available-for-sale securities	46	-72
Net unrealized gains (losses) on available-for-sale securities	300	-128
Net unrealized losses on available-for-sale securities designated in fair value hedges	-106	-97
Other-than-temporary impairment on available-for-sale securities related to factors other than credit	1	4
Net unrealized losses on hedges of net investments in non-U.S. subsidiaries	-14	-14
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	-31	-47
Net unrealized losses on retirement plans	-185	-203
Foreign currency translation	-289	229
Total	($107)	($95)

Shareholders_Equity_Accumulate

Shareholders' Equity (Accumulated Other Comprehensive Income by Component) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	($95)	'
Other comprehensive income (loss)	-596	409	-12	-474
AOCI net of tax, ending balance	-107	'	-107	'
Accumulated Other Comprehensive Income (Loss)	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	-95	360
Other comprehensive income (loss) before reclassifications	'	'	-25	-492
Amounts reclassified out of AOCI	'	'	13	18
Other comprehensive income (loss)	'	'	-12	-474
AOCI net of tax, ending balance	-107	-114	-107	-114
Net Unrealized Gains (Losses) on Cash Flow Hedges	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	161	69
Other comprehensive income (loss) before reclassifications	'	'	54	59
Amounts reclassified out of AOCI	'	'	2	2
Other comprehensive income (loss)	'	'	56	61
AOCI net of tax, ending balance	217	130	217	130
Net Unrealized Gains (Losses) on Available-for-Sale Securities	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	-221	519
Other comprehensive income (loss) before reclassifications	'	'	425	-578
Amounts reclassified out of AOCI	'	'	-9	-3
Other comprehensive income (loss)	'	'	416	-581
AOCI net of tax, ending balance	195	-62	195	-62
Net Unrealized Losses on Hedges of Net Investments in Non-U.S. Subsidiaries	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	-14	-14
Other comprehensive income (loss) before reclassifications	'	'	0	0
Amounts reclassified out of AOCI	'	'	0	0
Other comprehensive income (loss)	'	'	0	0
AOCI net of tax, ending balance	-14	-14	-14	-14
Other-Than-Temporary Impairment on Held-to-Maturity Securities	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	-47	-65
Other comprehensive income (loss) before reclassifications	'	'	15	11
Amounts reclassified out of AOCI	'	'	1	3
Other comprehensive income (loss)	'	'	16	14
AOCI net of tax, ending balance	-31	-51	-31	-51
Net Unrealized Losses on Retirement Plans	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	-203	-283
Other comprehensive income (loss) before reclassifications	'	'	-1	-6
Amounts reclassified out of AOCI	'	'	19	15
Other comprehensive income (loss)	'	'	18	9
AOCI net of tax, ending balance	-185	-274	-185	-274
Foreign Currency Translation	'	'	'	'
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]	'	'	'	'
AOCI net of tax, beginning balance	'	'	229	134
Other comprehensive income (loss) before reclassifications	'	'	-518	22
Amounts reclassified out of AOCI	'	'	0	1
Other comprehensive income (loss)	'	'	-518	23
AOCI net of tax, ending balance	($289)	$157	($289)	$157

Shareholders_Equity_Adjustment

Shareholders' Equity (Adjustments to Accumulated Other Comprehensive Income) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Class of Stock [Line Items]	'	'	'	'
Net interest revenue	$570	$546	$1,686	$1,718
Net gains (losses) from sales of available-for-sale securities	'	'	-15	-11
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	-591	326	-518	23
Total reclassifications out of AOCI	542	531	1,500	1,557
Reclassification out of Accumulated Other Comprehensive Income	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Total reclassifications out of AOCI	3	2	13	18
Net Unrealized Gains (Losses) on Cash Flow Hedges | Interest-rate contracts | Reclassification out of Accumulated Other Comprehensive Income	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	0	0	1	1
Net interest revenue	1	0	2	2
Net Unrealized Gains (Losses) on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Net gains (losses) from sales of available-for-sale securities	0	-4	-9	-7
Gain (Loss) on Investments, Excluding Other than Temporary Impairments, Tax	0	-2	-6	-4
Other-Than-Temporary Impairment on Held-to-Maturity Securities | Reclassification out of Accumulated Other Comprehensive Income	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	'	'	0	4
Held-to-maturity securities, Losses reclassified (from) to other comprehensive income	0	1	1	3
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income Loss, Tax, Including Portion Attributable to Noncontrolling Interest, Available-for-sale Securities	0	1	0	2
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Held-to-maturity Securities, Tax	0	0	0	3
Net Unrealized Losses on Retirement Plans | Reclassification out of Accumulated Other Comprehensive Income	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Amortization of actuarial losses, net of related tax benefits of $3 and $3, respectively	2	5	19	15
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Tax	3	3	-2	9
Foreign Currency Translation | Reclassification out of Accumulated Other Comprehensive Income	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	'	'	0	1
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax	$0	$0	$0	($1)

Regulatory_Capital_Details

Regulatory Capital (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'		'
Common stock and related surplus	'		$10,280	[1]
Retained earnings	14,531		13,395	[1]
Accumulated other comprehensive income (loss)	'		215	[1]
Treasury Stock Value, Excluding Preferred Shares	'		3,693	[1]
Total shareholders’ equity	'		20,197	[1]
Goodwill and other intangible assets, net of associated deferred tax liabilities	'		-7,743	[1],[2]
Other adjustments, common tier calculation	'		0	[1]
Tier one common risk-based capital	'		12,454	[1]
Preferred stock	'		491	[1]
Trust preferred capital securities subject to phase-out from tier 1 capital	'		950
Other adjustments, tier 1 risk based calculation	'		0	[1]
Tier One Risk Based Capital	'		13,895	[1]
Total Capital Qualifying Subordinated Long-Term Debt	'		1,918	[1]
Other adjustments, total capital calculation	'		-26	[1]
Capital	'		15,787	[1]
Risk-weighted assets - credit risk	'		78,864	[1]
Risk-weighted assets - market risk	'		1,262	[1]
Total risk-weighted assets	'		80,126	[1]
Adjusted Quarterly Average Assets	'		202,801	[1]
Tier One Common Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.00%	[3]	'
Tier 1 common risk-based capital	'		15.50%	[1]
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	5.50%	[3]	4.00%	[4]
Tier 1 risk-based capital	'		17.30%	[1]
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	[3]	8.00%	[4]
Total risk-based capital	'		19.70%	[1]
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	[3]	4.00%	[4]
Tier 1 leverage	'		6.90%	[1]
Basel III Advanced Approach	'		'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'		'
Common stock and related surplus	10,284	[5]	'
Retained earnings	14,531	[5]	'
Accumulated other comprehensive income (loss)	-264	[5]	'
Treasury Stock Value, Excluding Preferred Shares	4,785	[1]	'
Total shareholders’ equity	19,766	[5]	'
Goodwill and other intangible assets, net of associated deferred tax liabilities	-5,942	[2],[5]	'
Other adjustments, common tier calculation	-43	[5]	'
Tier one common risk-based capital	13,781	[5]	'
Preferred stock	1,233	[5]	'
Trust preferred capital securities subject to phase-out from tier 1 capital	475	[5]	'
Other adjustments, tier 1 risk based calculation	-171	[5]	'
Tier One Risk Based Capital	15,318	[5]	'
Total Capital Qualifying Subordinated Long-Term Debt	1,738	[1]	'
Trust preferred capital securities phased out of tier 1 capital	475	[5]	'
Other adjustments, total capital calculation	3	[5]	'
Capital	17,534	[5]	'
Risk-weighted assets - credit risk	67,915	[5]	'
Risk-weighted assets - operational risk	35,960	[5]	'
Risk-weighted assets - market risk	4,203	[5]	'
Total risk-weighted assets	108,078	[5]	'
Adjusted Quarterly Average Assets	240,529	[5]	'
Tier 1 common risk-based capital	12.80%	[5]	'
Tier 1 risk-based capital	14.20%	[5]	'
Total risk-based capital	16.20%	[5]	'
Tier 1 leverage	6.40%	[5]	'
Basel III Transitional Approach	'		'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'		'
Common stock and related surplus	10,284	[6]	'
Retained earnings	14,531	[6]	'
Accumulated other comprehensive income (loss)	-264	[6]	'
Treasury Stock Value, Excluding Preferred Shares	4,785	[1]	'
Total shareholders’ equity	19,766	[6]	'
Goodwill and other intangible assets, net of associated deferred tax liabilities	-5,942	[2],[6]	'
Other adjustments, common tier calculation	-43	[6]	'
Tier one common risk-based capital	13,781	[6]	'
Preferred stock	1,233	[6]	'
Trust preferred capital securities subject to phase-out from tier 1 capital	475	[6]	'
Other adjustments, tier 1 risk based calculation	-171	[6]	'
Tier One Risk Based Capital	15,318	[6]	'
Total Capital Qualifying Subordinated Long-Term Debt	1,738	[1]	'
Trust preferred capital securities phased out of tier 1 capital	475	[6]	'
Other adjustments, total capital calculation	3	[6]	'
Capital	17,534	[6]	'
Risk-weighted assets - credit risk	90,377	[6]	'
Risk-weighted assets - market risk	1,423	[6]	'
Total risk-weighted assets	91,800	[6]	'
Adjusted Quarterly Average Assets	240,529	[6]	'
Tier 1 common risk-based capital	15.00%	[6]	'
Tier 1 risk-based capital	16.70%	[6]	'
Total risk-based capital	19.10%	[6]	'
Tier 1 leverage	6.40%	[6]	'
State Street Bank	'		'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'		'
Common stock and related surplus	'		10,786	[1]
Retained earnings	'		9,064	[1]
Accumulated other comprehensive income (loss)	'		209	[1]
Treasury Stock Value, Excluding Preferred Shares	'		0	[1]
Total shareholders’ equity	'		20,059	[1]
Goodwill and other intangible assets, net of associated deferred tax liabilities	'		-7,341	[1],[2]
Other adjustments, common tier calculation	'		0	[1]
Tier one common risk-based capital	'		12,718	[1]
Preferred stock	'		0	[1]
Trust preferred capital securities subject to phase-out from tier 1 capital	'		0	[1]
Other adjustments, tier 1 risk based calculation	'		0	[1]
Tier One Risk Based Capital	'		12,718	[1]
Total Capital Qualifying Subordinated Long-Term Debt	'		1,936	[1]
Other adjustments, total capital calculation	'		45	[1]
Capital	'		14,699	[1]
Risk-weighted assets - credit risk	'		76,197	[1]
Risk-weighted assets - market risk	'		1,262	[1]
Total risk-weighted assets	'		77,459	[1]
Adjusted Quarterly Average Assets	'		199,301	[1]
Tier 1 common risk-based capital	'		16.40%	[1]
Tier 1 risk-based capital	'		16.40%	[1]
Total risk-based capital	'		19.00%	[1]
Tier 1 leverage	'		6.40%	[1]
State Street Bank | Basel III Advanced Approach	'		'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'		'
Common stock and related surplus	10,840	[5]	'
Retained earnings	9,500	[5]	'
Accumulated other comprehensive income (loss)	-220	[5]	'
Treasury Stock Value, Excluding Preferred Shares	0	[1]	'
Total shareholders’ equity	20,120	[5]	'
Goodwill and other intangible assets, net of associated deferred tax liabilities	-5,672	[2],[5]	'
Other adjustments, common tier calculation	-132	[5]	'
Tier one common risk-based capital	14,316	[5]	'
Preferred stock	0	[5]	'
Trust preferred capital securities subject to phase-out from tier 1 capital	0	[5]	'
Other adjustments, tier 1 risk based calculation	0	[5]	'
Tier One Risk Based Capital	14,316	[5]	'
Total Capital Qualifying Subordinated Long-Term Debt	1,754	[1]	'
Trust preferred capital securities phased out of tier 1 capital	0	[5]	'
Other adjustments, total capital calculation	0	[5]	'
Capital	16,070	[5]	'
Risk-weighted assets - credit risk	60,610	[5]	'
Risk-weighted assets - operational risk	35,530	[5]	'
Risk-weighted assets - market risk	3,707	[5]	'
Total risk-weighted assets	99,847	[5]	'
Adjusted Quarterly Average Assets	236,340	[5]	'
Tier 1 common risk-based capital	14.30%	[5]	'
Tier 1 risk-based capital	14.30%	[5]	'
Total risk-based capital	16.10%	[5]	'
Tier 1 leverage	6.10%	[5]	'
State Street Bank | Basel III Transitional Approach	'		'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'		'
Common stock and related surplus	10,840	[6]	'
Retained earnings	9,500	[6]	'
Accumulated other comprehensive income (loss)	-220	[6]	'
Treasury Stock Value, Excluding Preferred Shares	0	[1]	'
Total shareholders’ equity	20,120	[6]	'
Goodwill and other intangible assets, net of associated deferred tax liabilities	-5,672	[2],[6]	'
Other adjustments, common tier calculation	-132	[6]	'
Tier one common risk-based capital	14,316	[6]	'
Preferred stock	0	[6]	'
Trust preferred capital securities subject to phase-out from tier 1 capital	0	[6]	'
Other adjustments, tier 1 risk based calculation	0	[6]	'
Tier One Risk Based Capital	14,316	[6]	'
Total Capital Qualifying Subordinated Long-Term Debt	1,754	[1]	'
Trust preferred capital securities phased out of tier 1 capital	0	[6]	'
Other adjustments, total capital calculation	0	[6]	'
Capital	16,070	[6]	'
Risk-weighted assets - credit risk	87,150	[6]	'
Risk-weighted assets - market risk	1,423	[6]	'
Total risk-weighted assets	88,573	[6]	'
Adjusted Quarterly Average Assets	$236,340	[6]	'
Tier 1 common risk-based capital	16.20%	[6]	'
Tier 1 risk-based capital	16.20%	[6]	'
Total risk-based capital	18.10%	[6]	'
Tier 1 leverage	6.10%	[6]	'
[1]	Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of December 31, 2013 were calculated in conformity with the provisions of Basel I.
[2]	Amounts for State Street and State Street Bank as of September 30, 2014 consisted of goodwill, net of associated deferred tax liabilities, and 20% of other intangible assets, net of associated deferred tax liabilities, the latter phased in as a deduction from capital, in conformity with the Basel III final rule.
[3]	Minimum requirements will be phased in up to full implementation beginning on January 1, 2019; minimum requirements listed are as of September 30, 2014.
[4]	Minimum requirements listed, governed by Basel I, are as of December 31, 2013.
[5]	Tier 1 common capital, tier 1 capital and total capital ratios as of September 30, 2014 were calculated in conformity with the advanced approaches provisions of the Basel III final rule. Tier 1 leverage ratio as of September 30, 2014 was calculated in conformity with the Basel III final rule.
[6]	Tier 1 common capital, tier 1 capital, total capital and tier 1 leverage ratios as of September 30, 2014 were calculated in conformity with the transitional provisions of the Basel III final rule. Specifically, these ratios reflect tier 1 common, tier 1 and total capital (the numerator) calculated in conformity with the provisions of the Basel III final rule, and total risk-weighted assets or, with respect to the tier 1 leverage ratio, quarterly average assets (in both cases, the denominator), calculated in conformity with the provisions of Basel I.

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended			9 Months Ended			12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Derivative [Line Items]	'		'	'		'	'
Cash collateral received for derivative instruments	$1,370,000,000		'	$1,370,000,000		'	$2,580,000,000
Cash collateral provided for derivative instruments	4,320,000,000		'	4,320,000,000		'	3,360,000,000
Fair value of derivative liabilities	16,873,000,000	[1]	'	16,873,000,000	[1]	'	11,811,000,000	[1]
Maximum additional amount of payments related to termination events	110,000,000		'	110,000,000		'	'
Securities weighted average life (in years)	'		'	'6 years 1 month 4 days		'	'6 years 6 months
Other Comprehensive Income (Loss), Change in Unrealized Gain Loss on AFS Securities Designated as Fair Value Hedges, Net of Related Taxes	-14,000,000		-1,000,000	9,000,000		-61,000,000	'
Fair Value Hedges | 1.35% Senior Note	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Fixed interest rate	1.35%		'	1.35%		'	'
Fair Value Hedges | 3.70% senior notes due in 2023	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Fixed interest rate	3.70%		'	3.70%		'	'
Cash Flow Hedges	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Securities weighted average life (in years)	'		'	'1 month		'	'10 months
Credit swap agreements	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Fair value of derivative liabilities	2,490,000,000		'	2,490,000,000		'	'
Maximum additional amount of payments related to termination events	$2,380,000,000		'	$2,380,000,000		'	'
Interest rate swap | Fair Value Hedges | 3.1% Subordinated Note	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Fixed interest rate	3.10%		'	3.10%		'	'
Interest rate swap | Fair Value Hedges | Senior notes	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Number of securities	2		'	2		'	'
Interest rate swap | Fair Value Hedges | Subordinated note	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Number of securities	1		'	1		'	'
[1]	Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Schedule of Outstanding Hedges: (Notional Amount)) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	$5,212		$5,221
Credit derivative contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	8	[1]	0	[1]
Other contracts	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	227	[2]	42	[2]
Swap agreements and forwards | Interest-rate contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	842		1,023
Futures | Interest-rate contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	6,389		3,282
Futures | Foreign exchange contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	19		0
Forward, swap and spot | Foreign exchange contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	1,307,605		1,124,355
Options purchased | Foreign exchange contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	2,923		1,666
Options written | Foreign exchange contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	2,399		1,423
Credit swap agreements | Credit derivative contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	192		141
Commodity(1) | Futures Contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	555	[1]	2	[1]
Equity(1) | Futures Contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	86		1
Stable value contracts | Other contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	24,305		24,906
Swap agreements | Interest-rate contracts | Derivatives designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	5,212		5,221
Forward and swap | Foreign exchange contracts | Derivatives designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	2,693		2,783
Long | Options and caps purchased | Interest-rate contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	9		27
Short | Options and caps purchased | Interest-rate contracts | Derivatives not designated as hedging instruments	'		'
Derivative Instruments, Gain (Loss) [Line Items]	'		'
Notional amount of derivatives	$9		$27
[1]	Primarily composed of positions held by a consolidated sponsored investment fund, more fully described in note 9.
[2]	Represents grants of deferred cash awards to employees; refer to discussion in this note under "Derivatives Not Designated as Hedging Instruments."

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Notional Amount of Interest Rate Swap Agreements Designated as Fair Value and Cash Flow Hedges) (Details) (USD $)	9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Derivative [Line Items]	'		'
Total	$5,212		$5,221
Increase in carrying value of long-term debt	25		35
Investment securities available for sale	'		'
Derivative [Line Items]	'		'
Investment securities available for sale	2,712		2,721
Long-term debt	'		'
Derivative [Line Items]	'		'
Long-term debt	2,500	[1]	2,500	[1]
Fair Value Hedges	'		'
Derivative [Line Items]	'		'
Total	5,083		5,089
Fair Value Hedges | Investment securities available for sale	'		'
Derivative [Line Items]	'		'
Investment securities available for sale	2,583		2,589
Fair Value Hedges | Long-term debt	'		'
Derivative [Line Items]	'		'
Long-term debt	2,500	[1]	2,500	[1]
Cash Flow Hedges	'		'
Derivative [Line Items]	'		'
Total	129		132
Cash Flow Hedges | Investment securities available for sale	'		'
Derivative [Line Items]	'		'
Investment securities available for sale	129		132
Cash Flow Hedges | Long-term debt	'		'
Derivative [Line Items]	'		'
Long-term debt	$0	[1]	$0	[1]
[1]	As of September 30, 2014, these fair value hedges increased the carrying value of long-term debt presented in our consolidated statement of condition by $25 million. As of December 31, 2013, these fair value hedges decreased the carrying value of long-term debt presented in our consolidated statement of condition by $35 million.

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Contractual and Weighted-Average Interest Rates, Which Include the Effects of Hedges Related to Financial Instruments) (Details) (Long-term debt)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Long-term debt	'	'	'	'
Derivative [Line Items]	'	'	'	'
Contractual Rates	3.44%	3.34%	3.45%	3.49%
Rate Including Impact of Hedges	2.64%	2.67%	2.66%	2.77%

Derivative_Financial_Instrumen6

Derivative Financial Instruments (Schedule of The Fair Values of Derivative Financial Instruments) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	$16,932		$11,977	[1]
Fair value of derivative liabilities	16,873	[1]	11,811	[1]
Foreign exchange contracts	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	16,865		11,911	[1]
Fair value of derivative liabilities	16,559	[1]	11,471	[1]
Interest-rate contracts	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	63		65	[1]
Fair value of derivative liabilities	241	[1]	331	[1]
Derivatives not designated as hedging instruments | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	16,454		11,582
Derivatives not designated as hedging instruments | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	16,645		11,480
Derivatives not designated as hedging instruments | Foreign exchange contracts | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	16,434		11,552
Derivatives not designated as hedging instruments | Foreign exchange contracts | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	16,556		11,428
Derivatives not designated as hedging instruments | Interest-rate contracts | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	16		29
Derivatives not designated as hedging instruments | Interest-rate contracts | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	16		29
Derivatives not designated as hedging instruments | Other derivative contracts | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	4		1
Derivatives not designated as hedging instruments | Other derivative contracts | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	73		23
Derivatives designated as hedging instruments | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	478		395
Derivatives designated as hedging instruments | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	228		345
Derivatives designated as hedging instruments | Foreign exchange contracts | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	431		359
Derivatives designated as hedging instruments | Foreign exchange contracts | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	3		43
Derivatives designated as hedging instruments | Interest-rate contracts | Other assets	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative assets	47		36
Derivatives designated as hedging instruments | Interest-rate contracts | Other liabilities	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair value of derivative liabilities	$225		$302
[1]	Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.

Derivative_Financial_Instrumen7

Derivative Financial Instruments (Impact of Derivatives on Consolidated Statement of Income) (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$165		$148		$441		$465
Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	-66		0		49		-266
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	68		-1		-43		253
Compensation and employee benefits | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	18		4		89		10
Foreign exchange contracts | Trading services | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	163		147		441		461
Foreign exchange contracts | Processing fees and other revenue | Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	-82		20		-22		-135
Foreign exchange contracts | Processing fees and other revenue | Investment securities | Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	82		-20		22		135
Interest-rate contracts | Trading services | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	1		0		0		3
Interest-rate contracts | Processing fees and other revenue | Contract one | Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	24		-14		-17		-146
Interest-rate contracts | Processing fees and other revenue | Contract two | Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	-8		-6		88		15
Interest-rate contracts | Processing fees and other revenue | Long-term debt | Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	-23	[1]	7	[1]	15	[1]	-15	[1]
Interest-rate contracts | Processing fees and other revenue | Investment securities available for sale | Derivatives designated as fair value hedges	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	9		12		-80		133
Credit derivative contracts | Processing fees and other revenue | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	'		1		'		1
Other derivative contracts | Processing fees and other revenue | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	0		'		-1		'
Other derivative contracts | Compensation and employee benefits | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	18		4		89		10
Other Derivative Contracts [Member] | Trading services | Derivatives not designated as hedging instruments	'		'		'		'
Derivative [Line Items]	'		'		'		'
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$1		$0		$1		$0
[1]	Represents amounts reclassified out of other comprehensive income, or OCI. For the three and nine months ended September 30, 2014, $14 million of unrealized gains and $9 million of unrealized losses, respectively, on available-for-sale securities designated in fair value hedges were recognized in OCI. For the three and nine months ended September 30, 2013, $1 million and $61 million, respectively, of unrealized gains on available-for-sale securities designated in fair value hedges were recognized in OCI.

Derivative_Financial_Instrumen8

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		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative [Line Items]	'	'	'	'
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	$2,582	$2,425	$7,665	$7,420
Derivatives designed as cash flow value hedges	'	'	'	'
Derivative [Line Items]	'	'	'	'
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	91	-56	25	108
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	-1	-1	-3	-3
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	3	1	7	8
Interest-rate contracts | Derivatives designed as cash flow value hedges	'	'	'	'
Derivative [Line Items]	'	'	'	'
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	-1	-1	-3	10
Interest-rate contracts | Net interest revenue | Derivatives designed as cash flow value hedges	'	'	'	'
Derivative [Line Items]	'	'	'	'
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	-1	-1	-3	-3
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	1	1	3	3
Foreign exchange contracts | Derivatives designed as cash flow value hedges	'	'	'	'
Derivative [Line Items]	'	'	'	'
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	92	-55	28	98
Foreign exchange contracts | Net interest revenue | Derivatives designed as cash flow value hedges	'	'	'	'
Derivative [Line Items]	'	'	'	'
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	0	0	0	0
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$2	$0	$4	$5

Offsetting_Arrangements_Narrat

Offsetting Arrangements (Narrative) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Offsetting [Abstract]	'	'
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	$2,940,000,000	$5,640,000,000
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	$370,000,000	$1,770,000,000

Offsetting_Arrangements_Assets

Offsetting Arrangements (Assets With Offsetting Arrangements) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Offsetting Assets [Line Items]	'		'
Derivatives, Gross Amounts of Recognized Assets	$16,932		$11,977	[1]
Derivatives, Gross Amounts Offset in Statement of Condition	-8,220	[2]	-6,501	[2]
Net Amounts of Assets Presented in Statement of Condition	8,712		5,476
Resale Agreements and Securities Borrowing, Gross Amounts of Recognized Assets	48,078	[3]	48,221	[1],[3]
Resale Agreements and Securities Borrowing, Gross Amounts Offset in Statement of Condition	-29,692	[2],[3]	-30,700	[2],[3]
Net Amounts of Assets Presented in Statement of Condition	18,386	[3]	17,521	[3]
Total, Gross Amounts of Recognized Assets	65,010		60,198	[1]
Total, Gross Amounts Offset in Statement of Condition	-37,912	[2]	-37,201	[2]
Total, Net Amounts of Assets Presented in Statement of Condition	27,098		22,997
Securities purchased under resale agreements	2,603		6,230
Securities borrowed subject to master netting arrangements	15,783		11,291
Cash collateral netting	'		'
Offsetting Assets [Line Items]	'		'
Derivatives, Gross Amounts of Recognized Assets	0		0	[1]
Derivatives, Gross Amounts Offset in Statement of Condition	-841	[2]	-1,928	[2]
Net Amounts of Assets Presented in Statement of Condition	-841		-1,928
Interest-rate contracts	'		'
Offsetting Assets [Line Items]	'		'
Derivatives, Gross Amounts of Recognized Assets	63		65	[1]
Derivatives, Gross Amounts Offset in Statement of Condition	-34	[2]	-59	[2]
Net Amounts of Assets Presented in Statement of Condition	29		6
Foreign exchange contracts	'		'
Offsetting Assets [Line Items]	'		'
Derivatives, Gross Amounts of Recognized Assets	16,865		11,911	[1]
Derivatives, Gross Amounts Offset in Statement of Condition	-7,345	[2]	-4,514	[2]
Net Amounts of Assets Presented in Statement of Condition	9,520		7,397
Other derivative contracts	'		'
Offsetting Assets [Line Items]	'		'
Derivatives, Gross Amounts of Recognized Assets	4		1
Derivatives, Gross Amounts Offset in Statement of Condition	0		0
Net Amounts of Assets Presented in Statement of Condition	$4		$1
[1]	Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
[2]	Amounts subject to netting arrangements which have been determined to be legally enforceable.
[3]	Included in the $18,386 million as of September 30, 2014 were $2,603 million of resale agreements and $15,783 million of collateral provided related to securities borrowing. Included in the $17,521 million as of December 31, 2013 were $6,230 million of resale agreements and $11,291 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 7 for additional information with respect to principal securities finance transactions.

Offsetting_Arrangements_Assets1

Offsetting Arrangements (Assets With Enforceable Netting Arrangements) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Offsetting [Abstract]	'		'
Derivative, Net Amount of Assets Presented in Statement of Condition	$8,712		$5,476
Derivatives, Counterparty Netting	0	[1]	0	[1]
Derivatives, Collateral Received	-644	[1]	-181	[1]
Derivatives, Net Amount	8,068	[2]	5,295	[2]
Resale Agreements and Securities Borrowing, Resale Agreements and Securities Borrowing, Net Amount of Assets Presented in Statement of Condition	18,386	[3]	17,521	[3]
Resale Agreements and Securities Borrowing, Counterparty Netting	-108	[1]	-131	[1]
Resale Agreements and Securities Borrowing, Collateral Received	-18,185	[1]	-14,983	[1]
Resale Agreements and Securities Borrowing, Net Amount	93	[2]	2,407	[2]
Total, Net Amounts of Assets Presented in Statement of Condition	27,098		22,997
Total, Counterparty Netting	-108	[1]	-131	[1]
Total, Collateral Received	-18,829	[1]	-15,164	[1]
Total, Net Amount	$8,161	[2]	$7,702	[2]
[1]	Amounts subject to netting arrangements which have been determined to be legally enforceable
[2]	Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.
[3]	Included in the $18,386 million as of September 30, 2014 were $2,603 million of resale agreements and $15,783 million of collateral provided related to securities borrowing. Included in the $17,521 million as of December 31, 2013 were $6,230 million of resale agreements and $11,291 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 7 for additional information with respect to principal securities finance transactions.

Offsetting_Arrangements_Liabil

Offsetting Arrangements (Liabilities With Offsetting Arrangements) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Offsetting Liabilities [Line Items]	'		'
Gross Amounts of Recognized Liabilities	$16,873	[1]	$11,811	[1]
Gross Amounts Offset in Statement of Condition	-9,960	[1]	-5,552	[1],[2]
Net Amounts of Liabilities Presented in Statement of Condition	6,913	[1]	6,259
Gross Amounts of Recognized Liabilities	46,089	[1],[3]	45,273	[1],[3]
Gross Amounts Offset in Statement of Condition	-29,692	[2],[3]	-30,700	[2],[3]
Net Amounts of Liabilities Presented in Statement of Condition	16,397	[3]	14,573	[3]
Gross Amounts of Recognized Liabilities	62,962	[1]	57,084	[1]
Gross Amounts Offset in Statement of Condition	-39,652	[2]	-36,252	[2]
Total, Net Amount of Liabilities Presented in Statement of Condition	23,310		20,832
Securities sold under repurchase agreements	9,385		7,953
Securities Lending, Fair Value, Amount Not Offset Against Collateral	7,012		6,620
Cash collateral netting	'		'
Offsetting Liabilities [Line Items]	'		'
Gross Amounts of Recognized Liabilities	0	[1]	0	[1]
Gross Amounts Offset in Statement of Condition	-2,581		-979	[2]
Net Amounts of Liabilities Presented in Statement of Condition	-2,581		-979
Interest-rate contracts	'		'
Offsetting Liabilities [Line Items]	'		'
Gross Amounts of Recognized Liabilities	241	[1]	331	[1]
Gross Amounts Offset in Statement of Condition	-34	[2]	-59	[2]
Net Amounts of Liabilities Presented in Statement of Condition	207		272
Foreign exchange contracts	'		'
Offsetting Liabilities [Line Items]	'		'
Gross Amounts of Recognized Liabilities	16,559	[1]	11,471	[1]
Gross Amounts Offset in Statement of Condition	-7,345	[2]	-4,514	[2]
Net Amounts of Liabilities Presented in Statement of Condition	9,214		6,957
Other derivative contracts	'		'
Offsetting Liabilities [Line Items]	'		'
Gross Amounts of Recognized Liabilities	73		9	[1]
Gross Amounts Offset in Statement of Condition	0		0	[2]
Net Amounts of Liabilities Presented in Statement of Condition	$73		$9
[1]	Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
[2]	Amounts subject to netting arrangements which have been determined to be legally enforceable.
[3]	Included in the $16,397 million as of September 30, 2014 were $9,385 million of repurchase agreements and $7,012 million of collateral received related to securities lending. Included in the $14,573 million as of December 31, 2013 were $7,953 million of repurchase agreements and $6,620 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 liabilities, respectively, in our consolidated statement of condition. Refer to note 7 for additional information with respect to principal securities finance transactions.

Offsetting_Arrangements_Liabil1

Offsetting Arrangements (Liabilities With Enforceable Netting Arrangements) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Offsetting [Abstract]	'		'
Derivative, Net Amount of Liabilities Presented in Statement of Condition	$6,913	[1]	$6,259
Derivative, Counterparty Netting	0	[2]	0	[2]
Derivative, Collateral Provided	-78	[2]	-6	[2]
Derivative, Net Amount	6,835	[3]	6,253	[3]
Repurchase Agreements and Securities Lending, Net Amount of Liabilities Presented in Statement of Condition	16,397	[4]	14,573	[4]
Repurchase Agreements and Securities Lending, Counterparty Netting	-108	[2]	-131	[2]
Repurchase Agreements and Securities Lending, Collateral Provided	-14,173	[2]	-13,036	[2]
Repurchase Agreements and Securities Lending, Net Amount	2,116	[3]	1,406	[3]
Total, Net Amount of Liabilities Presented in Statement of Condition	23,310		20,832
Total, Counterparty Netting	-108	[2]	-131	[2]
Total, Collateral Provided	-14,251	[2]	-13,042	[2]
Total, Net Amount	$8,951	[3]	$7,659	[3]
[1]	Amounts include all transactions regardless of whether or not they are subject to an enforceable netting arrangement.
[2]	Amounts subject to netting arrangements which have been determined to be legally enforceable
[3]	Includes amounts secured by collateral not determined to be subject to enforceable netting arrangements.
[4]	Included in the $16,397 million as of September 30, 2014 were $9,385 million of repurchase agreements and $7,012 million of collateral received related to securities lending. Included in the $14,573 million as of December 31, 2013 were $7,953 million of repurchase agreements and $6,620 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 liabilities, respectively, in our consolidated statement of condition. Refer to note 7 for additional information with respect to principal securities finance transactions.

Net_Interest_Revenue_Component

Net Interest Revenue (Components of Interest Revenue and Interest Expenses) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Interest Revenue [Abstract]	'	'	'	'
Deposits with banks	$53	$29	$138	$91
U.S. Treasury and federal agencies	165	165	493	542
State and political subdivisions	58	59	173	164
Other investments	320	323	957	1,003
Securities purchased under resale agreements	9	8	27	33
Loans and leases	64	58	183	193
Other interest-earning assets	2	1	5	4
Total interest revenue	671	643	1,976	2,030
Deposits	33	17	66	78
Short-term borrowings	0	15	4	46
Long-term debt	60	59	186	169
Other interest-bearing liabilities	8	6	34	19
Total interest expense	101	97	290	312
Net interest revenue	$570	$546	$1,686	$1,718

Expenses_Narrative_Details

Expenses (Narrative) (Details) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2011

Dec. 31, 2010

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Business Operations And Information Technology Transformation Program

Expenses Control Measures - Additional Targeted Staff Reductions

Expenses Control Measures - Additional Targeted Staff Reductions

Expenses Control Measures - Additional Targeted Staff Reductions

Expenses Control Measures - Additional Targeted Staff Reductions

Expenses Control Measures - Additional Targeted Staff Reductions

Involuntary Terminations

Involuntary Terminations

Involuntary Terminations

Involuntary Terminations

Involuntary Terminations After Replacements

employee

employee

employee

employee

employee

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Severance costs

($2)

'

$74

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restructuring charges incurred to date

'

'

'

'

402

'

'

'

'

'

'

'

'

'

'

'

'

Restructuring charges, net

$8

$12

$33

$22

$21

$25

$67

$133

$156

'

'

'

$12

$3

$133

'

'

Expected number of positions eliminated

'

'

'

'

'

'

'

'

'

1,574

1,400

'

'

'

'

960

630

Percent of actual number of positions eliminated

'

'

'

'

'

'

'

'

'

'

5.00%

'

'

'

'

'

'

Number of positions eliminated from inception to date

'

'

'

'

'

'

'

'

'

'

'

1,522

'

'

'

'

'

Expenses_Costs_Related_To_Acqu

Expenses (Costs Related To Acquisition And Restructuring) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Expenses [Abstract]	'	'	'	'
Acquisition costs	$12	$18	$48	$52
Restructuring charges, net	8	12	33	22
Total acquisition and restructuring costs	$20	$30	$81	$74

Expenses_Activity_Related_To_R

Expenses (Activity Related To Restructuring-Related Accruals) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Restructuring Reserve [Roll Forward]	'
Balance as of December 31, 2013	$106
Additional accruals for Business Operations and Information Technology Transformation program	21
Payments and adjustments	-80
Balance as of March 31, 2014	59
2012 Expense Control Measures	'
Restructuring Reserve [Roll Forward]	'
Additional accruals for 2012 expense control measures	12
Employee- Related Costs	'
Restructuring Reserve [Roll Forward]	'
Balance as of December 31, 2013	50
Additional accruals for Business Operations and Information Technology Transformation program	14
Payments and adjustments	-37
Balance as of March 31, 2014	28
Employee- Related Costs | 2012 Expense Control Measures	'
Restructuring Reserve [Roll Forward]	'
Additional accruals for 2012 expense control measures	1
Real Estate Consolidation	'
Restructuring Reserve [Roll Forward]	'
Balance as of December 31, 2013	49
Additional accruals for Business Operations and Information Technology Transformation program	7
Payments and adjustments	-36
Balance as of March 31, 2014	20
Real Estate Consolidation | 2012 Expense Control Measures	'
Restructuring Reserve [Roll Forward]	'
Additional accruals for 2012 expense control measures	0
Asset and Other Write-Offs	'
Restructuring Reserve [Roll Forward]	'
Balance as of December 31, 2013	7
Additional accruals for Business Operations and Information Technology Transformation program	0
Payments and adjustments	-7
Balance as of March 31, 2014	11
Asset and Other Write-Offs | 2012 Expense Control Measures	'
Restructuring Reserve [Roll Forward]	'
Additional accruals for 2012 expense control measures	$11

Earnings_Per_Common_Share_Comp

Earnings Per Common Share (Computation of Basic and Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended				9 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share [Abstract]	'		'		'		'
Net income	$560		$540		$1,545		$1,583
Less: Preferred stock dividends	-18		-7		-43		-20
Less: Dividends and undistributed earnings allocated to participating securities	0	[1]	-2	[1]	-2	[1]	-6	[1]
Net income available to common shareholders	$542		$531		$1,500		$1,557
Basic average common shares	421,974		442,860		426,775		449,742
Effect of dilutive securities: common stock options and common stock awards (in shares)	7,762		9,294		7,735		8,650
Diluted average shares	429,736		452,154		434,510		458,392
Anti-dilutive securities (in shares)	876	[2]	1,788	[2]	1,502	[2]	2,384	[2]
Earnings per Common Share:	'		'		'		'
Basic (in dollars per share)	$1.28		$1.20		$3.52		$3.46
Diluted (in dollars per share)	$1.26	[3]	$1.17	[3]	$3.45	[3]	$3.40	[3]
[1]	Represented the portion of net income available to common equity allocated to participating securities, composed of fully vested deferred director stock and unvested restricted stock that contain non-forfeitable rights to dividends during the vesting period on a basis equivalent to dividends paid to common shareholders.
[2]	Represented common stock options and other equity-based awards outstanding but not included in the computation of diluted average common shares, because their effect was anti-dilutive.
[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_D

Line of Business Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
			line_of_business
Segment Reporting Information [Line Items]	'	'	'	'
Number of lines of business	'	'	2	'
Severance costs	($2,000,000)	'	$74,000,000	'
Acquisition and restructuring costs	-20,000,000	-30,000,000	-81,000,000	-74,000,000
Servicing fees	1,302,000,000	1,211,000,000	3,828,000,000	3,587,000,000
Management fees	316,000,000	276,000,000	908,000,000	816,000,000
Trading services	278,000,000	265,000,000	791,000,000	858,000,000
Securities finance	99,000,000	74,000,000	331,000,000	283,000,000
Processing fees and other	17,000,000	57,000,000	117,000,000	167,000,000
Total fee revenue	2,012,000,000	1,883,000,000	5,975,000,000	5,711,000,000
Net interest revenue	570,000,000	546,000,000	1,686,000,000	1,718,000,000
Gains (losses) related to investment securities, net	0	-4,000,000	4,000,000	-9,000,000
Total revenue	2,582,000,000	2,425,000,000	7,665,000,000	7,420,000,000
Provision for loan losses	2,000,000	0	6,000,000	0
Total expenses	1,892,000,000	1,722,000,000	5,770,000,000	5,346,000,000
Income before income tax expense	688,000,000	703,000,000	1,889,000,000	2,074,000,000
Pre-tax margin	27.00%	29.00%	25.00%	28.00%
Total Average Assets	247,300,000,000	201,300,000,000	232,600,000,000	205,700,000,000
Investment Servicing	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Servicing fees	1,302,000,000	1,211,000,000	3,828,000,000	3,587,000,000
Management fees	0	0	0	0
Trading services	266,000,000	251,000,000	756,000,000	803,000,000
Securities finance	99,000,000	74,000,000	331,000,000	283,000,000
Processing fees and other	25,000,000	52,000,000	122,000,000	157,000,000
Total fee revenue	1,692,000,000	1,588,000,000	5,037,000,000	4,830,000,000
Net interest revenue	551,000,000	527,000,000	1,634,000,000	1,655,000,000
Gains (losses) related to investment securities, net	0	-4,000,000	4,000,000	-9,000,000
Total revenue	2,243,000,000	2,111,000,000	6,675,000,000	6,476,000,000
Provision for loan losses	2,000,000	0	6,000,000	0
Total expenses	1,639,000,000	1,500,000,000	4,905,000,000	4,639,000,000
Income before income tax expense	602,000,000	611,000,000	1,764,000,000	1,837,000,000
Pre-tax margin	27.00%	29.00%	26.00%	28.00%
Total Average Assets	243,200,000,000	197,700,000,000	229,000,000,000	201,900,000,000
Investment Management	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Servicing fees	0	0	0	0
Management fees	316,000,000	276,000,000	908,000,000	816,000,000
Trading services	12,000,000	14,000,000	35,000,000	55,000,000
Securities finance	0	0	0	0
Processing fees and other	-8,000,000	5,000,000	-5,000,000	10,000,000
Total fee revenue	320,000,000	295,000,000	938,000,000	881,000,000
Net interest revenue	19,000,000	19,000,000	52,000,000	63,000,000
Gains (losses) related to investment securities, net	0	0	0	0
Total revenue	339,000,000	314,000,000	990,000,000	944,000,000
Provision for loan losses	0	0	0	0
Total expenses	239,000,000	187,000,000	708,000,000	613,000,000
Income before income tax expense	100,000,000	127,000,000	282,000,000	331,000,000
Pre-tax margin	29.00%	40.00%	28.00%	35.00%
Total Average Assets	4,100,000,000	3,600,000,000	3,600,000,000	3,800,000,000
Other	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Acquisition and restructuring costs	-20,000,000	'	-81,000,000	'
Provision for litigation exposure and other costs	-4,000,000	5,000,000	2,000,000	20,000,000
Claims resolution	'	30,000,000	'	74,000,000
Servicing fees	0	0	0	0
Management fees	0	0	0	0
Trading services	0	0	0	0
Securities finance	0	0	0	0
Processing fees and other	0	0	0	0
Total fee revenue	0	0	0	0
Net interest revenue	0	0	0	0
Gains (losses) related to investment securities, net	0	0	0	0
Total revenue	0	0	0	0
Provision for loan losses	0	0	0	0
Total expenses	14,000,000	35,000,000	157,000,000	94,000,000
Income before income tax expense	($14,000,000)	($35,000,000)	($157,000,000)	($94,000,000)

NonUS_Activities_Schedule_Of_R

Non-U.S. Activities (Schedule Of Results From Non-U.S. Operations) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Total fee revenue	$2,012	$1,883	$5,975	$5,711
Net interest revenue	570	546	1,686	1,718
Gains (losses) related to investment securities, net	0	-4	4	-9
Total revenue	2,582	2,425	7,665	7,420
Expenses	1,892	1,722	5,770	5,346
Income before income tax expense	688	703	1,889	2,074
Income tax expense	128	163	344	491
Net income	560	540	1,545	1,583
Non- U.S.	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Total fee revenue	862	771	2,488	2,347
Net interest revenue	325	306	991	874
Gains (losses) related to investment securities, net	1	-2	6	-12
Total revenue	1,188	1,075	3,485	3,209
Expenses	791	786	2,443	2,279
Income before income tax expense	397	289	1,042	930
Income tax expense	96	74	248	228
Net income	$301	$215	$794	$702

NonUS_Activities_Summary_Of_No

Non-U.S. Activities (Summary Of Non-U.S. Assets) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Segment Reporting Information [Line Items]	'	'
Interest-bearing deposits with banks	$86,946	$64,257
Other assets	34,145	25,990
Total assets	274,805	243,291
Non- U.S.	'	'
Segment Reporting Information [Line Items]	'	'
Interest-bearing deposits with banks	9,828	9,584
Investment securities	30,791	31,522
Other assets	17,326	16,778
Total assets	$57,945	$57,884