BASIS OF PRESENTATION AND ACCOUNTING CHANGES (Policies)	3 Months Ended
Mar. 31, 2016
Accounting Policies [Abstract]
Accounting Changes	ACCOUNTING CHANGES Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, which addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. This ASU requires entities to present separately in OCI the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (DVA) when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. It will also require equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, thus eliminating eligibility for the current available-for-sale category. However, Federal Reserve Bank and Federal Home Loan Bank stock as well as exchange seats will continue to be presented at cost. Citi early-adopted only the provisions of this ASU related to presentation of DVA in OCI effective January 1, 2016, as permitted by the ASU. Accordingly, beginning in the first quarter 2016, the portion of the change in fair value of liabilities for which the fair value option was elected related to changes in Citigroup’s own credit spreads (DVA) is reflected as a component of Accumulated other comprehensive income (AOCI), whereas, these amounts were previously recognized in Citigroup’s revenues and net income. The impact of adopting this amendment resulted in a cumulative catch-up reclassification from retained earnings to AOCI of an accumulated after tax loss of approximately $15 million at January 1, 2016. Financial statements for periods prior to 2016 were not subject to restatement under the provisions of this ASU. For additional information, see Note 18, Note 22 and Note 23 to the Consolidated Financial Statements. The Company is evaluating the effect that the other provisions of ASU 2016-01 will have on its Consolidated Financial Statements and related disclosures. Accounting for Investments in Tax Credit Partnerships In January 2014, the FASB issued ASU No. 2014-01, Investments—Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects. Any transition adjustment is reflected as an adjustment to retained earnings in the earliest period presented (retrospective application). The ASU is applicable to Citi’s portfolio of low income housing tax credit (LIHTC) partnership interests. The new standard widens the scope of investments eligible to elect to apply a new alternative method, the proportional amortization method, under which the cost of the investment is amortized to tax expense in proportion to the amount of tax credits and other tax benefits received. Citi qualifies to elect the proportional amortization method under the ASU for its entire LIHTC portfolio. These investments were previously accounted for under the equity method, which resulted in losses (due to amortization of the investment) being recognized in Other revenue and tax credits and benefits being recognized in the Income tax expense line. In contrast, the proportional amortization method combines the amortization of the investment and receipt of the tax credits/benefits into one line, Income tax expense. Citi adopted ASU 2014-01 in the first quarter of 2015. The adoption of this ASU was applied retrospectively and cumulatively reduced Retained earnings by approximately $349 million, Other assets by approximately $178 million, and deferred tax assets by approximately $171 million. Consolidation In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis, which intended to improve certain areas of consolidation guidance for legal entities such as limited partnerships, limited liability companies, and securitization structures. The ASU reduced the number of consolidation models and became effective on January 1, 2016. Adoption of ASU 2015-02 did not have a material impact on the Company’s Consolidated Financial Statements. Consolidation-Collateralized Financing Entities In August 2014, the FASB issued ASU No. 2014-13, Consolidation (Topic 810): Measuring the Financial Assets and the Financial Liabilities of a Consolidated Collateralized Financing Entity, which provides an alternative measurement method for consolidated collateralized financing VIEs to elect: (i) to measure their financial assets and liabilities separately under existing U.S. GAAP for fair value measurement with any differences in such fair values reflected in earnings; or (ii) to measure both their financial assets and liabilities using the more observable of the fair value of the financial assets or the fair value of the financial liabilities. The ASU became effective on January 1, 2016. Adoption of ASU 2014-13 did not have a material impact on the Company’s Consolidated Financial Statements. FUTURE APPLICATION OF ACCOUNTING STANDARDS Recognition of Breakage for Certain Prepaid Stored-Value Products In March 2016, the FASB issued ASU No. 2016-04, Liabilities—Extinguishment of Liabilities (Subtopic 405-20): Recognition of Breakage for Certain Prepaid Stored-Value Products, which was intended to address potential diversity in entities’ practices related to the derecognition of the financial liability that is recorded when an entity issues a prepaid stored-value product. Typically, when the holder of a prepaid stored-value product redeems that product to make a purchase of goods or services, the issuing entity settles the transaction with the selling merchant, and the liability to the product holder is extinguished. However, in some cases, a prepaid stored-value product may be wholly or partially unused for an indefinite time period. The ASU provides authoritative guidance describing the narrow circumstances in which an entity’s liability for an unredeemed prepaid stored-value product may be extinguished. The amendment is effective on January 1, 2018; early adoption is permitted. Adoption of the ASU is not expected to have a material impact on the Company’s Consolidated Financial Statements. Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in GAAP when it becomes effective on January 1, 2018. Early application is permitted for annual periods beginning after December 15, 2016. The ASU is not applicable to financial instruments and, therefore, is not expected to impact a majority of the Company’s revenue, including net interest income. The Company is evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. Accounting for Financial Instruments—Credit Losses In December 2012, the FASB issued a proposed ASU, Financial Instruments—Credit Losses. This proposed ASU, or exposure draft, was issued for public comment in order to allow stakeholders the opportunity to review the proposal and provide comments to the FASB and does not constitute accounting guidance until a final ASU is issued. The exposure draft contains proposed guidance developed by the FASB with the goal of improving financial reporting about expected credit losses on loans, securities and other financial assets held by financial institutions and other organizations. The exposure draft proposes a new accounting model intended to require earlier recognition of credit losses, while also providing additional transparency about credit risk. The FASB’s proposed model would utilize an “expected credit loss” measurement objective for the recognition of credit losses for loans, held-to-maturity securities and other receivables at the time the financial asset is originated or acquired and adjusted each period for changes in expected credit losses. For available-for-sale securities where fair value is less than cost, credit-related impairment would be recognized in an allowance for credit losses and adjusted each period for changes in credit risk. This would replace the multiple existing impairment models in GAAP, which generally require that a loss be incurred before it is recognized. The FASB’s proposed model represents a significant departure from existing GAAP, and may result in material changes to the Company’s accounting for financial instruments. The impact of the FASB’s final ASU on the Company’s Consolidated Financial Statements will be assessed when it is issued. The Company expects that the final ASU will be effective for Citi as of January 1, 2020. Early application is permitted for annual periods beginning January 1, 2019. Lease Accounting In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which is intended to increase transparency and comparability of accounting for lease transactions. The ASU will require lessees to recognize all leases on the balance sheet as lease assets and lease liabilities and will require both quantitative and qualitative disclosures regarding key information about leasing arrangements. Lessor accounting is largely unchanged. The guidance is effective beginning January 1, 2019 with an option to early adopt. The Company is evaluating whether to early adopt and the effect that ASU 2016-02 will have on its consolidated financial statements, regulatory capital and related disclosures.

ACCOUNTING CHANGES

Recognition and Measurement of Financial Assets and Financial Liabilities

In January 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, which addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments.

This ASU requires entities to present separately in OCI the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (DVA) when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. It will also require equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, thus eliminating eligibility for the current available-for-sale category. However, Federal Reserve Bank and Federal Home Loan Bank stock as well as exchange seats will continue to be presented at cost.

Citi early-adopted only the provisions of this ASU related to presentation of DVA in OCI effective January 1, 2016, as permitted by the ASU. Accordingly, beginning in the first quarter 2016, the portion of the change in fair value of liabilities for which the fair value option was elected related to changes in Citigroup’s own credit spreads (DVA) is reflected as a component of Accumulated other comprehensive income (AOCI), whereas, these amounts were previously recognized in Citigroup’s revenues and net income. The impact of adopting this amendment resulted in a cumulative catch-up reclassification from retained earnings to AOCI of an accumulated after tax loss of approximately $15 million at January 1, 2016. Financial statements for periods prior to 2016 were not subject to restatement under the provisions of this ASU. For additional information, see Note 18, Note 22 and Note 23 to the Consolidated Financial Statements. The Company is evaluating the effect that the other provisions of ASU 2016-01 will have on its Consolidated Financial Statements and related disclosures.

Accounting for Investments in Tax Credit Partnerships

In January 2014, the FASB issued ASU No. 2014-01, Investments—Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects. Any transition adjustment is reflected as an adjustment to retained earnings in the earliest period presented (retrospective application).

The ASU is applicable to Citi’s portfolio of low income housing tax credit (LIHTC) partnership interests. The new standard widens the scope of investments eligible to elect to apply a new alternative method, the proportional amortization method, under which the cost of the investment is amortized to tax expense in proportion to the amount of tax credits and other tax benefits received. Citi qualifies to elect the proportional amortization method under the ASU for its entire LIHTC portfolio. These investments were previously accounted for under the equity method, which resulted in losses (due to amortization of the investment) being recognized in Other revenue and tax credits and benefits being recognized in the Income tax expense line. In contrast, the proportional amortization method combines the amortization of the investment and receipt of the tax credits/benefits into one line, Income tax expense.

Citi adopted ASU 2014-01 in the first quarter of 2015.

The adoption of this ASU was applied retrospectively and cumulatively reduced Retained earnings by approximately $349 million, Other assets by approximately $178 million, and deferred tax assets by approximately $171 million.

Consolidation

In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis, which intended to improve certain areas of consolidation guidance for legal entities such as limited partnerships, limited liability companies, and securitization structures. The ASU reduced the number of consolidation models and became effective on January 1, 2016. Adoption of ASU 2015-02 did not have a material impact on the Company’s Consolidated Financial Statements.

Consolidation-Collateralized Financing Entities

In August 2014, the FASB issued ASU No. 2014-13, Consolidation (Topic 810): Measuring the Financial Assets and the Financial Liabilities of a Consolidated Collateralized Financing Entity, which provides an alternative measurement method for consolidated collateralized financing VIEs to elect: (i) to measure their financial assets and liabilities separately under existing U.S. GAAP for fair value measurement with any differences in such fair values reflected in earnings; or (ii) to measure both their financial assets and liabilities using the more observable of the fair value of the financial assets or the fair value of the financial liabilities. The ASU became effective on January 1, 2016. Adoption of ASU 2014-13 did not have a material impact on the Company’s Consolidated Financial

Statements.

FUTURE APPLICATION OF ACCOUNTING STANDARDS

Recognition of Breakage for Certain Prepaid Stored-Value Products

In March 2016, the FASB issued ASU No. 2016-04, Liabilities—Extinguishment of Liabilities (Subtopic 405-20): Recognition of Breakage for Certain Prepaid Stored-Value Products, which was intended to address potential diversity in entities’ practices related to the derecognition of the financial liability that is recorded when an entity issues a prepaid stored-value product. Typically, when the holder of a prepaid stored-value product redeems that product to make a purchase of goods or services, the issuing entity settles the transaction with the selling merchant, and the liability to the product holder is extinguished. However, in some cases, a prepaid stored-value product may be wholly or partially unused for an indefinite time period.

The ASU provides authoritative guidance describing the narrow circumstances in which an entity’s liability for an unredeemed prepaid stored-value product may be extinguished. The amendment is effective on January 1, 2018; early adoption is permitted. Adoption of the ASU is not expected to have a material impact on the Company’s Consolidated Financial Statements.

Revenue Recognition

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in GAAP when it becomes effective on January 1, 2018. Early application is permitted for annual periods beginning after December 15, 2016. The ASU is not applicable to financial instruments and, therefore, is not expected to impact a majority of the Company’s revenue, including net interest income. The Company is evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures.

Accounting for Financial Instruments—Credit Losses

In December 2012, the FASB issued a proposed ASU, Financial Instruments—Credit Losses. This proposed ASU, or exposure draft, was issued for public comment in order to allow stakeholders the opportunity to review the proposal and provide comments to the FASB and does not constitute accounting guidance until a final ASU is issued.

The exposure draft contains proposed guidance developed by the FASB with the goal of improving financial reporting about expected credit losses on loans, securities and other financial assets held by financial institutions and other organizations. The exposure draft proposes a new accounting model intended to require earlier recognition of credit losses, while also providing additional transparency about credit risk.

The FASB’s proposed model would utilize an “expected credit loss” measurement objective for the recognition of credit losses for loans, held-to-maturity securities and other receivables at the time the financial asset is originated or acquired and adjusted each period for changes in expected credit losses. For available-for-sale securities where fair value is less than cost, credit-related impairment would be recognized in an allowance for credit losses and adjusted each period for changes in credit risk. This would replace the multiple existing impairment models in GAAP, which generally require that a loss be incurred before it is recognized.

The FASB’s proposed model represents a significant departure from existing GAAP, and may result in material changes to the Company’s accounting for financial instruments. The impact of the FASB’s final ASU on the Company’s Consolidated Financial Statements will be assessed when it is issued. The Company expects that the final ASU will be effective for Citi as of January 1, 2020. Early application is permitted for annual periods beginning January 1, 2019.

Lease Accounting

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which is intended to increase transparency and comparability of accounting for lease transactions. The ASU will require lessees to recognize all leases on the balance sheet as lease assets and lease liabilities and will require both quantitative and qualitative disclosures regarding key information about leasing arrangements. Lessor accounting is largely unchanged. The guidance is effective beginning January 1, 2019 with an option to early adopt. The Company is evaluating whether to early adopt and the effect that ASU 2016-02 will have on its consolidated financial statements, regulatory capital and related disclosures.