Recent Accounting Pronouncements	12 Months Ended
Dec. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09). ASU 2014-09 is a converged standard between the FASB and the International Accounting Standards Board (IASB) that provides a single comprehensive revenue recognition model for all contracts with customers across transactions and industries. The primary objective of ASU 2014-09 is revenue recognition that represents the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 is effective for interim and annual reporting periods beginning after December 15, 2017. Northern Trust is currently assessing the impact of adoption of ASU 2014-09. In February 2015, the FASB issued ASU No. 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis” (ASU 2015-02) which changes the guidance with respect to the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The amendments include: (1) modifying the evaluation of limited partnerships and similar legal entities, (2) amending when fees paid to a decision maker should be included in the variable interest entity analysis, (3) amending the related party relationship guidance, and (4) providing a scope exception from the consolidation guidance for reporting entities with interests in certain investment funds. ASU 2015-02 is effective for interim and annual reporting periods beginning after December 15, 2015, although early adoption is permitted. The adoption of ASU 2015-02 by Northern Trust, effective January 1, 2016, will result in additional disclosures, but will not significantly impact Northern Trust’s consolidated financial position or results of operations. In April 2015, the FASB issued ASU No. 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03) which requires that debt issuance costs be presented in the balance sheet as a direct deduction to the carrying amount of the associated debt liability. ASU 2015-03 is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The adoption of ASU 2015-03 by Northern Trust, effective January 1, 2016, will not significantly impact Northern Trust’s consolidated financial position or results of operations. In April 2015, the FASB issued ASU No. 2015-05, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement” (ASU 2015-05) which clarifies whether fees paid by a customer in a cloud computing arrangement pertain to the acquisition of a software license, services, or both. ASU 2015-05 is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The adoption of ASU 2015-05 by Northern Trust, effective January 1, 2016, will not significantly impact Northern Trust’s consolidated financial position or results of operations. In September 2015, the FASB issued ASU No. 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments” (ASU 2015-16) which requires that the acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amount is determined. Further, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date, are to be recorded in the same period's financial statements. ASU 2015-16 is effective for interim and annual periods beginning after December 15, 2015, although earlier application is permitted for financial statements that have not been issued. The adoption of ASU 2015-16 by Northern Trust, effective January 1, 2016, will not significantly impact Northern Trust's consolidated financial position or results of operations. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (ASU 2016-01). ASU 2016-01 requires equity investments (except those accounted for under the equity method or those that result in consolidation) to be measured at fair value with changes in fair value recognized in net income unless a policy election is made for investments without readily determinable fair values. Additionally, ASU 2016-01 requires public entities to use the exit price notion when measuring the fair value of financial instruments for measurement purposes, and eliminates the requirement to disclose the method(s) and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost on the balance sheet. Furthermore, it requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. ASU 2016-01 is effective for interim and annual periods beginning after December 15, 2017. Northern Trust is currently assessing the impact of adoption of ASU 2016-01.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (ASU 2014-09). ASU 2014-09 is a converged standard between the FASB and the International Accounting Standards Board (IASB) that provides a single comprehensive revenue recognition model for all contracts with customers across transactions and industries. The primary objective of ASU 2014-09 is revenue recognition that represents the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 is effective for interim and annual reporting periods beginning after December 15, 2017. Northern Trust is currently assessing the impact of adoption of ASU 2014-09.

In February 2015, the FASB issued ASU No. 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis” (ASU 2015-02) which changes the guidance with respect to the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The amendments include: (1) modifying the evaluation of limited partnerships and similar legal entities, (2) amending when fees paid to a decision maker should be included in the variable interest entity analysis, (3) amending the related party relationship guidance, and (4) providing a scope exception from the consolidation guidance for reporting entities with interests in certain investment funds. ASU 2015-02 is effective for interim and annual reporting periods beginning after December 15, 2015, although early adoption is permitted. The adoption of ASU 2015-02 by Northern Trust, effective January 1, 2016, will result in additional disclosures, but will not significantly impact Northern Trust’s consolidated financial position or results of operations.

In April 2015, the FASB issued ASU No. 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03) which requires that debt issuance costs be presented in the balance sheet as a direct deduction to the carrying amount of the associated debt liability. ASU 2015-03 is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The adoption of ASU 2015-03 by Northern Trust, effective January 1, 2016, will not significantly impact Northern Trust’s consolidated financial position or results of operations.

In April 2015, the FASB issued ASU No. 2015-05, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement” (ASU 2015-05) which clarifies whether fees paid by a customer in a cloud computing arrangement pertain to the acquisition of a software license, services, or both. ASU 2015-05 is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The adoption of ASU 2015-05 by Northern Trust, effective January 1, 2016, will not significantly impact Northern Trust’s consolidated financial position or results of operations.

In September 2015, the FASB issued ASU No. 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments” (ASU 2015-16) which requires that the acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amount is determined. Further, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date, are to be recorded in the same period's financial statements. ASU 2015-16 is effective for interim and annual periods beginning after December 15, 2015, although earlier application is permitted for financial statements that have not been issued. The adoption of ASU 2015-16 by Northern Trust, effective January 1, 2016, will not significantly impact Northern Trust's consolidated financial position or results of operations.

In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (ASU 2016-01). ASU 2016-01 requires equity investments (except those accounted for under the equity method or those that result in consolidation) to be measured at fair value with changes in fair value recognized in net income unless a policy election is made for investments without readily determinable fair values. Additionally, ASU 2016-01 requires public entities to use the exit price notion when measuring the fair value of financial instruments for measurement purposes, and eliminates the requirement to disclose the method(s) and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost on the balance sheet. Furthermore, it requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. ASU 2016-01 is effective for interim and annual periods beginning after December 15, 2017. Northern Trust is currently assessing the impact of adoption of ASU 2016-01.