Basis of Presentation	3 Months Ended
Mar. 31, 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 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. Our adoption of the amendment is not expected to have a material effect on our consolidated financial statements.

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 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. Our adoption of the amendment is not expected to have a material effect on our consolidated financial statements.