Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies Ally Financial Inc. (together with its consolidated subsidiaries unless the context requires otherwise, Ally, the Company, or we, us, or our) is a leading digital financial services company and top 25 U.S. financial holding company (FHC) based on total assets, offering diversified financial products and services for consumers, businesses, automotive dealers, and corporate clients. Ally operates with a distinctive brand, an innovative approach, and a relentless focus on our customers. We are a Delaware corporation and are registered as a bank holding company (BHC) under the Bank Holding Company Act of 1956 as amended and an FHC under the Gramm-Leach-Bliley Act of 1999 as amended. We are one of the largest full service automotive finance operations in the country with a legacy that dates back to 1919, a deep expertise in automotive lending, and a complementary automotive-focused insurance business. Our wholly-owned banking subsidiary, Ally Bank, has received numerous industry awards for its services and capabilities and is one of the largest and most respected online banks, uniquely positioned for the observed shifting trends in consumer banking preferences for digital banking. We offer mortgage lending services and a variety of deposit and other banking products, including CDs, online savings, money market and checking accounts, and IRA products. We also promote a cash back credit card. We have recently integrated a growing digital wealth management and online brokerage platform to enable consumers to have a variety of options in managing their savings and wealth. Additionally, through our corporate finance business, we primarily offer senior secured leveraged cash flow and asset-based loans to middle-market companies. Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and that affect income and expenses during the reporting period and related disclosures. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ because of uncertainties associated with estimating the amounts, timing, and likelihood of possible outcomes. Our most significant estimates pertain to the allowance for loan losses, valuations of automotive lease assets and residuals, fair value of financial instruments, legal and regulatory reserves, and the determination of the provision for income taxes. The Condensed Consolidated Financial Statements at March 31, 2018, and for the three months ended March 31, 2018, and 2017, are unaudited but reflect all adjustments that are, in management’s opinion, necessary for the fair presentation of the results for the interim periods presented. All such adjustments are of a normal recurring nature. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements (and the related Notes) included in our Annual Report on Form 10-K for the year ended December 31, 2017, as filed on February 21, 2018, with the U.S. Securities and Exchange Commission (SEC). Significant Accounting Policies Investments Our investment portfolio includes various debt and equity securities. Our debt securities include government securities, corporate bonds, asset-backed securities (ABS), and mortgage-backed securities (MBS). Debt securities are classified based on management’s intent to sell or hold the security. We classify debt securities as held-to-maturity only when we have both the intent and ability to hold the securities to maturity. We classify debt securities as trading when the securities are acquired for the purpose of selling or holding them for a short period of time. Debt securities not classified as either held-to-maturity or trading are classified as available-for-sale. Our portfolio includes debt securities classified as available-for-sale and held-to-maturity. Our available-for-sale debt securities are carried at fair value with unrealized gains and losses included in accumulated other comprehensive loss and are subject to impairment. Our held-to-maturity debt securities are carried at amortized cost and are subject to impairment. We assess our debt securities for potential other-than-temporary impairment. We employ a methodology that considers available evidence in evaluating potential other-than-temporary impairment of our debt securities classified as available-for-sale and held-to-maturity. If the cost of an investment exceeds its fair value, we evaluate, among other factors, the magnitude and duration of the decline in fair value. We also evaluate the financial health of and business outlook for the issuer, the performance of the underlying assets for interests in securitized assets, and, for debt securities classified as available-for-sale, our intent and ability to hold the investment through recovery of its amortized cost basis. Once a decline in fair value of a debt security is determined to be other-than-temporary, an impairment charge for the credit component is recorded to other gain (loss) on investments, net, in our Condensed Consolidated Statement of Comprehensive Income, and a new cost basis in the investment is established. The noncredit loss component of an available-for-sale debt security continues to be recorded in other comprehensive (loss) income when we do not intend to sell the security and it is not more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Both the credit and noncredit loss components are recorded in earnings when we intend to sell the security or it is more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Subsequent increases and decreases to the fair value of available-for-sale debt securities are included in other comprehensive (loss) income, so long as they are not attributable to another other-than-temporary impairment. We amortize premiums and discounts on debt securities as an adjustment to investment yield generally over the stated maturity of the security. For ABS and MBS where prepayments can be reasonably estimated, amortization is adjusted for expected prepayments. Our investment in equity securities includes securities that are recognized at fair value with changes in the market value recorded in earnings, and equity securities that are recognized using other measurement principles. Effective January 1, 2018, equity securities that are publicly traded and have a readily determinable fair value, as well as certain investments that do not have a readily determinable fair value and are not eligible to be recognized using other measurement principles, are recorded at fair value with changes in fair value recorded in earnings and reported in other gain (loss) on investments, net in our Condensed Consolidated Statement of Comprehensive Income. These investments, which are primarily attributable to the investment portfolio of our Insurance operations, are included in equity securities on our Condensed Consolidated Balance Sheet. Refer to Note 6 for further information on our equity securities that have a readily determinable market value. Our equity securities recognized using other measurement principles include investments in Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock held to meet regulatory requirements, equity investments related to low income housing tax credits and the Community Reinvestment Act (CRA), which are not publicly traded and do not have a readily determinable fair value, and other equity investments that are not publicly traded and do not have a readily determinable fair value. Our low income housing tax credit investments are accounted for using the proportional amortization method of accounting for qualified affordable housing investments. Our obligations related to unfunded commitments for our low income housing tax credit investments are included in other liabilities. The majority of our CRA investments are accounted for using the equity method of accounting. Our investments in low income housing tax credits and CRA investments are included in other assets on our Condensed Consolidated Balance Sheet. Our investments in FHLB and FRB stock are carried at cost. Our remaining investments in equity securities are recorded at cost, less impairment and adjusted for observable price differences under the measurement alternative provided under GAAP. These investments, along with our investments in FHLB and FRB stock, are included in nonmarketable equity investments in other assets on our Condensed Consolidated Balance Sheet. As conditions warrant, we review these investments for impairment and adjust the carrying value of the investment if it is deemed to be impaired. Investments recorded under the measurement alternative are also reviewed at each reporting period to determine if any adjustments are required for observable price changes in identical or similar securities. Realized gains and losses on the sale of securities are determined using the specific identification method and are reported in other gain (loss) on investments, net in our Condensed Consolidated Statement of Comprehensive Income. Derivative Instruments and Hedging Activities We use derivative instruments primarily for risk management purposes. We do not use derivative instruments for speculative purposes. Certain of our derivative instruments are designated as accounting hedges in qualifying relationships, whereas other derivative instruments have not been designated as accounting hedges. In accordance with applicable accounting standards, all derivative instruments, whether designated for hedge accounting or not, are required to be recorded on the balance sheet as assets or liabilities and measured at fair value. We have elected to report the fair value of derivative assets and liabilities on a gross basis—including the fair value for the right to reclaim cash collateral or the obligation to return cash collateral—arising from instruments executed with the same counterparty under a master netting arrangement where we do not have the intent to offset. For additional information on derivative instruments and hedging activities, refer to Note 18. At the inception of a hedge accounting relationship, we designate each qualifying hedge relationship as a hedge of the fair value of a specifically identified asset or liability (fair value hedge); as a hedge of the variability of cash flows to be received or paid, or forecasted to be received or paid, related to a recognized asset or liability (cash flow hedge); or as a hedge of the foreign-currency exposure of a net investment in a foreign operation (net investment hedge). We formally document all relationships between hedging instruments and hedged items, as well as the risk management objectives for undertaking various hedge transactions. Both at hedge inception and on an ongoing basis, we formally assess whether the derivatives that are used in hedging relationships are highly effective in offsetting changes in fair values or cash flows of hedged items. Changes in the fair value of derivative instruments qualifying as fair value hedges, along with the gain or loss on the hedged asset or liability attributable to the hedged risk, are recorded in current period earnings. For qualifying cash flow hedges, the changes in fair value of the derivative financial instruments are recorded in accumulated other comprehensive loss and recognized in the income statement when the hedged cash flows affect earnings. For a qualifying net investment hedge, the gain or loss is reported in accumulated other comprehensive loss as part of the cumulative translation adjustment. Hedge accounting treatment is no longer applied if a derivative financial instrument is terminated, or if the hedge designation is removed or assessed to be no longer highly effective. For terminated fair value hedges, any changes to the hedged asset or liability remain as part of the basis of the hedged asset or liability and are recognized into income over the remaining life of the asset or liability. For terminated cash flow hedges, unless it is probable that the forecasted cash flows will not occur within a specified period, any changes in fair value of the derivative financial instrument previously recognized remain in accumulated other comprehensive loss, and are reclassified into earnings in the same period that the hedged cash flows affect earnings. Any previously recognized gain or loss for a net investment hedge continues to remain in accumulated other comprehensive loss until earnings are impacted by sale or liquidation of the associated foreign operation. In all instances, after hedge accounting is no longer applied, any subsequent changes in fair value of the derivative instrument will be recorded into earnings. Changes in the fair value of derivative financial instruments held for risk management purposes that are not designated as accounting hedges under GAAP are reported in current period earnings. Income Taxes In calculating the provision for interim income taxes, in accordance with Accounting Standards Codification (ASC) 740, Income Taxes, we apply an estimated annual effective tax rate to year-to-date ordinary income. At the end of each interim period, we estimate the effective tax rate expected to be applicable for the full fiscal year. This method differs from that described in Note 1 to the Consolidated Financial Statements in our 2017 Annual Report on Form 10-K, which describes our annual significant income tax accounting policy and related methodology. Refer to Note 1 to the Consolidated Financial Statements in our 2017 Annual Report on Form 10-K regarding additional significant accounting policies. Recently Adopted Accounting Standards Statement of Cash Flows — Restricted Cash (ASU 2016-18) As of December 31, 2017, we elected to early-adopt Accounting Standards Update (ASU) 2016-18. The amendments in this update require that amounts classified as restricted cash and restricted cash equivalents be included within the beginning-of-period and end-of-period amounts along with cash and cash equivalents on the statement of cash flows. The amendments were applied retrospectively to all periods presented within the statement of cash flows. The implementation of this guidance resulted in a change in presentation of our Condensed Consolidated Statement of Cash Flows and additional disclosures surrounding restricted cash balances, but did not result in a change to our Condensed Consolidated Statement of Comprehensive Income or Condensed Consolidated Balance Sheet. Revenue from Contracts with Customers (ASU 2014-09) In May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09. The purpose of this guidance is to streamline and consolidate existing revenue recognition principles in GAAP and to converge revenue recognition principles with International Financial Reporting Standards. The core principle of the amendments is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive in exchange for those goods or services. The amendments include a five step process for consideration of the core principle, guidance on the accounting treatment for costs associated with a contract, and disclosure requirements related to the revenue process. The FASB issued several additional ASUs to clarify guidance and provide implementation support for ASU 2014-09. The clarifying guidance elaborates on the key concepts within ASU 2014-09 and clarifies how those concepts interact with other GAAP requirements. On January 1, 2018, we adopted ASU 2014-09 and all subsequent ASUs that modified ASU 2014-09 (collectively, the amendments to the revenue recognition principles), which have been codified in ASC 606, Revenue from Contracts with Customers, and ASC 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets, respectively. We elected to adopt this guidance using the modified retrospective approach applied to all contracts with customers that were not completed as of January 1, 2018. The adoption of the amendments resulted in a reduction to our opening retained earnings of approximately $126 million, net of income taxes. Refer to Note 2 for further details. Financial Instruments — Recognition and Measurement of Financial Assets (ASU 2016-01) As of January 1, 2018, we adopted ASU 2016-01. The amendments in this update modify the requirements related to the measurement of certain financial instruments in the statement of financial condition and results of operations. The FASB subsequently issued ASU 2018-03 to clarify guidance and provide implementation support for ASU 2016-01, which we elected to early-adopt as of January 1, 2018, to align with the adoption of ASU 2016-01. For equity investments (other than investments accounted for using the equity method), entities must measure such instruments at fair value with changes in fair value recognized in net income. Changes in fair value for equity securities are no longer recognized through other comprehensive (loss) income, which creates additional volatility in our Condensed Consolidated Statement of Comprehensive Income. Reporting entities may continue to elect to measure certain equity investments that do not have a readily determinable fair value at cost with adjustments for impairment and observable changes in price. In addition, for a liability (other than a derivative liability) that an entity measures at fair value, any change in fair value related to the instrument-specific credit risk, that is the entity’s own-credit, should be presented separately in other comprehensive (loss) income and not as a component of net income. We adopted these amendments, as required, on a modified retrospective basis with a cumulative effect adjustment as of the beginning of the fiscal year of initial adoption. The adoption of the amendments resulted in a reduction to our opening retained earnings of approximately $20 million, net of income taxes. Derivatives and Hedging — Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12) As of January 1, 2018, we elected to early-adopt ASU 2017-12. The amendments in this update enhance the financial reporting of hedging relationships to better align hedge accounting with an entity’s risk management activities. This update also makes certain targeted improvements to simplify the application of the hedge accounting guidance in current GAAP and better portrays economic results through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. We adopted the amendments to all cash flow and net investment hedge relationships that existed on the date of adoption using a modified retrospective approach. No cumulative effect adjustment to our opening retained earnings was required as a result of the adoption. The presentation and disclosure requirements included in this update were adopted prospectively. Refer to Note 18 for further details. Accumulated Other Comprehensive Income — Reclassification of Certain Tax Effects (ASU 2018-02) In February 2018, the FASB issued ASU 2018-02. The amendments in this update provide guidance concerning the treatment of the impact of income tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act) on items included in accumulated other comprehensive income. Our policy is to use the portfolio method with respect to reclassification of stranded income tax effects in accumulated other comprehensive loss. The amendments in ASU 2018-02 provide entities an election to reclassify the income tax effect of the Tax Act from accumulated other comprehensive income to retained earnings. We elected to early-adopt this standard as of January 1, 2018, and reclassified the effect of the change in the federal corporate income tax rate on items included in accumulated other comprehensive loss. This election resulted in a reclassification of $42 million from accumulated other comprehensive loss to retained earnings. Recently Issued Accounting Standards Leases (ASU 2016-02) In February 2016, the FASB issued ASU 2016-02. The amendments in this update primarily replace the existing accounting requirements for operating leases for lessees. Lessee accounting requirements for finance leases and lessor accounting requirements for operating leases and sales type and direct financing leases (sales type and direct financing leases were both previously referred to as capital leases) are largely unchanged. The amendments require the lessee of an operating lease to record a balance sheet gross-up upon lease commencement by recognizing a right-of-use asset and lease liability equal to the present value of the lease payments. The right-of-use asset and lease liability should be derecognized in a manner that effectively yields a straight line lease expense over the lease term. In addition to the changes to the lessee operating lease accounting requirements, the amendments also change the types of costs that can be capitalized related to a lease agreement for both lessees and lessors for all types of leases. The amendments also require additional disclosures for all lease types for both lessees and lessors. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied on a modified retrospective basis with a cumulative adjustment to the beginning of the earliest fiscal year presented in the financial statements in the period of adoption. Upon adoption, we expect to record a balance sheet gross-up, reflecting our right-of-use asset and lease liability for our operating leases where we are the lessee (for example, our facility leases). While we are currently reviewing our operating lease contracts where we are the lessee to determine the impact of the gross-up and the changes to capitalizable costs, as well as reviewing our leases where we are the lessor to determine the impact of the changes to capitalizable costs, we do not anticipate the adoption of these amendments will have a material impact to our financial statements. We currently plan to adopt these amendments on January 1, 2019, and expect to use the modified retrospective approach as required. Financial Instruments — Credit Losses (ASU 2016-13) In June 2016, the FASB issued ASU 2016-13. The amendments in this update introduce a new accounting model to measure credit losses for financial assets measured at amortized cost. Credit losses for financial assets measured at amortized cost should be determined based on the total current expected credit losses over the life of the financial asset or group of financial assets. In effect, the financial asset or group of financial assets should be presented at the net amount expected to be collected. Credit losses will no longer be recorded under the current incurred loss model for financial assets measured at amortized cost. The amendments also modify the accounting for available-for-sale debt securities whereby credit losses will be recorded through an allowance for credit losses rather than a write-down to the security’s cost basis, which allows for reversals of credit losses when estimated credit losses decline. Credit losses for available-for-sale debt securities should be measured in a manner similar to current GAAP. The amendments are effective on January 1, 2020, with early adoption permitted as of January 1, 2019. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. The new accounting model for credit losses represents a significant departure from existing GAAP, and will likely materially increase the allowance for credit losses with a resulting negative adjustment to retained earnings. Management created a formal working group to govern the implementation of these amendments consisting of key stakeholders from finance, risk, and accounting and is currently evaluating the impact of the amendments. We are in the process of designing and building the models and procedures that will be used to calculate the credit loss reserves in accordance with these amendments. We currently plan to adopt these amendments on January 1, 2020, and expect to use the modified retrospective approach as required. Receivables — Nonrefundable Fees and Other Costs: Premium Amortization on Purchased Callable Debt Securities (ASU 2017-08) In March 2017, the FASB issued ASU 2017-08. The amendments in this update require premiums on purchased callable debt securities to be amortized to the security’s earliest call date. Prior to this ASU, premiums and discounts on purchased callable debt securities were generally required to be amortized to the security’s maturity date. The amendments do not require an accounting change for securities held at a discount. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. While our assessment is not final, we do not expect the amendments to have a material impact to our financial statements. We currently plan to adopt these amendments on January 1, 2019, and expect to use the modified retrospective approach as required.

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies

Ally Financial Inc. (together with its consolidated subsidiaries unless the context requires otherwise, Ally, the Company, or we, us, or our) is a leading digital financial services company and top 25 U.S. financial holding company (FHC) based on total assets, offering diversified financial products and services for consumers, businesses, automotive dealers, and corporate clients. Ally operates with a distinctive brand, an innovative approach, and a relentless focus on our customers. We are a Delaware corporation and are registered as a bank holding company (BHC) under the Bank Holding Company Act of 1956 as amended and an FHC under the Gramm-Leach-Bliley Act of 1999 as amended. We are one of the largest full service automotive finance operations in the country with a legacy that dates back to 1919, a deep expertise in automotive lending, and a complementary automotive-focused insurance business. Our wholly-owned banking subsidiary, Ally Bank, has received numerous industry awards for its services and capabilities and is one of the largest and most respected online banks, uniquely positioned for the observed shifting trends in consumer banking preferences for digital banking. We offer mortgage lending services and a variety of deposit and other banking products, including CDs, online savings, money market and checking accounts, and IRA products. We also promote a cash back credit card. We have recently integrated a growing digital wealth management and online brokerage platform to enable consumers to have a variety of options in managing their savings and wealth. Additionally, through our corporate finance business, we primarily offer senior secured leveraged cash flow and asset-based loans to middle-market companies.

Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and that affect income and expenses during the reporting period and related disclosures. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ because of uncertainties associated with estimating the amounts, timing, and likelihood of possible outcomes. Our most significant estimates pertain to the allowance for loan losses, valuations of automotive lease assets and residuals, fair value of financial instruments, legal and regulatory reserves, and the determination of the provision for income taxes.

The Condensed Consolidated Financial Statements at March 31, 2018, and for the three months ended March 31, 2018, and 2017, are unaudited but reflect all adjustments that are, in management’s opinion, necessary for the fair presentation of the results for the interim periods presented. All such adjustments are of a normal recurring nature. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements (and the related Notes) included in our Annual Report on Form 10-K for the year ended December 31, 2017, as filed on February 21, 2018, with the U.S. Securities and Exchange Commission (SEC).

Significant Accounting Policies

Investments

Our investment portfolio includes various debt and equity securities. Our debt securities include government securities, corporate bonds, asset-backed securities (ABS), and mortgage-backed securities (MBS). Debt securities are classified based on management’s intent to sell or hold the security. We classify debt securities as held-to-maturity only when we have both the intent and ability to hold the securities to maturity. We classify debt securities as trading when the securities are acquired for the purpose of selling or holding them for a short period of time. Debt securities not classified as either held-to-maturity or trading are classified as available-for-sale.

Our portfolio includes debt securities classified as available-for-sale and held-to-maturity. Our available-for-sale debt securities are carried at fair value with unrealized gains and losses included in accumulated other comprehensive loss and are subject to impairment. Our held-to-maturity debt securities are carried at amortized cost and are subject to impairment.

We assess our debt securities for potential other-than-temporary impairment. We employ a methodology that considers available evidence in evaluating potential other-than-temporary impairment of our debt securities classified as available-for-sale and held-to-maturity. If the cost of an investment exceeds its fair value, we evaluate, among other factors, the magnitude and duration of the decline in fair value. We also evaluate the financial health of and business outlook for the issuer, the performance of the underlying assets for interests in securitized assets, and, for debt securities classified as available-for-sale, our intent and ability to hold the investment through recovery of its amortized cost basis.

Once a decline in fair value of a debt security is determined to be other-than-temporary, an impairment charge for the credit component is recorded to other gain (loss) on investments, net, in our Condensed Consolidated Statement of Comprehensive Income, and a new cost basis in the investment is established. The noncredit loss component of an available-for-sale debt security continues to be recorded in other comprehensive (loss) income when we do not intend to sell the security and it is not more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Both the credit and noncredit loss components are recorded in earnings when we intend to sell the security or it is more likely than not that we will have to sell the security prior to the security’s anticipated recovery. Subsequent increases and decreases to the fair value of available-for-sale debt securities are included in other comprehensive (loss) income, so long as they are not attributable to another other-than-temporary impairment.

We amortize premiums and discounts on debt securities as an adjustment to investment yield generally over the stated maturity of the security. For ABS and MBS where prepayments can be reasonably estimated, amortization is adjusted for expected prepayments.

Our investment in equity securities includes securities that are recognized at fair value with changes in the market value recorded in earnings, and equity securities that are recognized using other measurement principles.

Effective January 1, 2018, equity securities that are publicly traded and have a readily determinable fair value, as well as certain investments that do not have a readily determinable fair value and are not eligible to be recognized using other measurement principles, are recorded at fair value with changes in fair value recorded in earnings and reported in other gain (loss) on investments, net in our Condensed Consolidated Statement of Comprehensive Income. These investments, which are primarily attributable to the investment portfolio of our Insurance operations, are included in equity securities on our Condensed Consolidated Balance Sheet. Refer to Note 6 for further information on our equity securities that have a readily determinable market value.

Our equity securities recognized using other measurement principles include investments in Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock held to meet regulatory requirements, equity investments related to low income housing tax credits and the Community Reinvestment Act (CRA), which are not publicly traded and do not have a readily determinable fair value, and other equity investments that are not publicly traded and do not have a readily determinable fair value. Our low income housing tax credit investments are accounted for using the proportional amortization method of accounting for qualified affordable housing investments. Our obligations related to unfunded commitments for our low income housing tax credit investments are included in other liabilities. The majority of our CRA investments are accounted for using the equity method of accounting. Our investments in low income housing tax credits and CRA investments are included in other assets on our Condensed Consolidated Balance Sheet. Our investments in FHLB and FRB stock are carried at cost. Our remaining investments in equity securities are recorded at cost, less impairment and adjusted for observable price differences under the measurement alternative provided under GAAP. These investments, along with our investments in FHLB and FRB stock, are included in nonmarketable equity investments in other assets on our Condensed Consolidated Balance Sheet. As conditions warrant, we review these investments for impairment and adjust the carrying value of the investment if it is deemed to be impaired. Investments recorded under the measurement alternative are also reviewed at each reporting period to determine if any adjustments are required for observable price changes in identical or similar securities.

Realized gains and losses on the sale of securities are determined using the specific identification method and are reported in other gain (loss) on investments, net in our Condensed Consolidated Statement of Comprehensive Income.

Derivative Instruments and Hedging Activities

We use derivative instruments primarily for risk management purposes. We do not use derivative instruments for speculative purposes. Certain of our derivative instruments are designated as accounting hedges in qualifying relationships, whereas other derivative instruments have not been designated as accounting hedges. In accordance with applicable accounting standards, all derivative instruments, whether designated for hedge accounting or not, are required to be recorded on the balance sheet as assets or liabilities and measured at fair value. We have elected to report the fair value of derivative assets and liabilities on a gross basis—including the fair value for the right to reclaim cash collateral or the obligation to return cash collateral—arising from instruments executed with the same counterparty under a master netting arrangement where we do not have the intent to offset. For additional information on derivative instruments and hedging activities, refer to Note 18.

At the inception of a hedge accounting relationship, we designate each qualifying hedge relationship as a hedge of the fair value of a specifically identified asset or liability (fair value hedge); as a hedge of the variability of cash flows to be received or paid, or forecasted to be received or paid, related to a recognized asset or liability (cash flow hedge); or as a hedge of the foreign-currency exposure of a net investment in a foreign operation (net investment hedge). We formally document all relationships between hedging instruments and hedged items, as well as the risk management objectives for undertaking various hedge transactions. Both at hedge inception and on an ongoing basis, we formally assess whether the derivatives that are used in hedging relationships are highly effective in offsetting changes in fair values or cash flows of hedged items.

Changes in the fair value of derivative instruments qualifying as fair value hedges, along with the gain or loss on the hedged asset or liability attributable to the hedged risk, are recorded in current period earnings. For qualifying cash flow hedges, the changes in fair value of the derivative financial instruments are recorded in accumulated other comprehensive loss and recognized in the income statement when the hedged cash flows affect earnings. For a qualifying net investment hedge, the gain or loss is reported in accumulated other comprehensive loss as part of the cumulative translation adjustment.

Hedge accounting treatment is no longer applied if a derivative financial instrument is terminated, or if the hedge designation is removed or assessed to be no longer highly effective. For terminated fair value hedges, any changes to the hedged asset or liability remain as part of the basis of the hedged asset or liability and are recognized into income over the remaining life of the asset or liability. For terminated cash flow hedges, unless it is probable that the forecasted cash flows will not occur within a specified period, any changes in fair value of the derivative financial instrument previously recognized remain in accumulated other comprehensive loss, and are reclassified into earnings in the same period that the hedged cash flows affect earnings. Any previously recognized gain or loss for a net investment hedge continues to remain in accumulated other comprehensive loss until earnings are impacted by sale or liquidation of the associated foreign operation. In all instances, after hedge accounting is no longer applied, any subsequent changes in fair value of the derivative instrument will be recorded into earnings.

Changes in the fair value of derivative financial instruments held for risk management purposes that are not designated as accounting hedges under GAAP are reported in current period earnings.

Income Taxes

In calculating the provision for interim income taxes, in accordance with Accounting Standards Codification (ASC) 740, Income Taxes, we apply an estimated annual effective tax rate to year-to-date ordinary income. At the end of each interim period, we estimate the effective tax rate expected to be applicable for the full fiscal year. This method differs from that described in Note 1 to the Consolidated Financial Statements in our 2017 Annual Report on Form 10-K, which describes our annual significant income tax accounting policy and related methodology.

Refer to Note 1 to the Consolidated Financial Statements in our 2017 Annual Report on Form 10-K regarding additional significant accounting policies.

Recently Adopted Accounting Standards

Statement of Cash Flows — Restricted Cash (ASU 2016-18)

As of December 31, 2017, we elected to early-adopt Accounting Standards Update (ASU) 2016-18. The amendments in this update require that amounts classified as restricted cash and restricted cash equivalents be included within the beginning-of-period and end-of-period amounts along with cash and cash equivalents on the statement of cash flows. The amendments were applied retrospectively to all periods presented within the statement of cash flows. The implementation of this guidance resulted in a change in presentation of our Condensed Consolidated Statement of Cash Flows and additional disclosures surrounding restricted cash balances, but did not result in a change to our Condensed Consolidated Statement of Comprehensive Income or Condensed Consolidated Balance Sheet.

Revenue from Contracts with Customers (ASU 2014-09)

In May 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-09. The purpose of this guidance is to streamline and consolidate existing revenue recognition principles in GAAP and to converge revenue recognition principles with International Financial Reporting Standards. The core principle of the amendments is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive in exchange for those goods or services. The amendments include a five step process for consideration of the core principle, guidance on the accounting treatment for costs associated with a contract, and disclosure requirements related to the revenue process. The FASB issued several additional ASUs to clarify guidance and provide implementation support for ASU 2014-09. The clarifying guidance elaborates on the key concepts within ASU 2014-09 and clarifies how those concepts interact with other GAAP requirements. On January 1, 2018, we adopted ASU 2014-09 and all subsequent ASUs that modified ASU 2014-09 (collectively, the amendments to the revenue recognition principles), which have been codified in ASC 606, Revenue from Contracts with Customers, and ASC 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets, respectively. We elected to adopt this guidance using the modified retrospective approach applied to all contracts with customers that were not completed as of January 1, 2018. The adoption of the amendments resulted in a reduction to our opening retained earnings of approximately $126 million, net of income taxes. Refer to Note 2 for further details.

Financial Instruments — Recognition and Measurement of Financial Assets (ASU 2016-01)

As of January 1, 2018, we adopted ASU 2016-01. The amendments in this update modify the requirements related to the measurement of certain financial instruments in the statement of financial condition and results of operations. The FASB subsequently issued ASU 2018-03 to clarify guidance and provide implementation support for ASU 2016-01, which we elected to early-adopt as of January 1, 2018, to align with the adoption of ASU 2016-01. For equity investments (other than investments accounted for using the equity method), entities must measure such instruments at fair value with changes in fair value recognized in net income. Changes in fair value for equity securities are no longer recognized through other comprehensive (loss) income, which creates additional volatility in our Condensed Consolidated Statement of Comprehensive Income. Reporting entities may continue to elect to measure certain equity investments that do not have a readily determinable fair value at cost with adjustments for impairment and observable changes in price. In addition, for a liability (other than a derivative liability) that an entity measures at fair value, any change in fair value related to the instrument-specific credit risk, that is the entity’s own-credit, should be presented separately in other comprehensive (loss) income and not as a component of net income. We adopted these amendments, as required, on a modified retrospective basis with a cumulative effect adjustment as of the beginning of the fiscal year of initial adoption. The adoption of the amendments resulted in a reduction to our opening retained earnings of approximately $20 million, net of income taxes.

Derivatives and Hedging — Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12)

As of January 1, 2018, we elected to early-adopt ASU 2017-12. The amendments in this update enhance the financial reporting of hedging relationships to better align hedge accounting with an entity’s risk management activities. This update also makes certain targeted improvements to simplify the application of the hedge accounting guidance in current GAAP and better portrays economic results through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. We adopted the amendments to all cash flow and net investment hedge relationships that existed on the date of adoption using a modified retrospective approach. No cumulative effect adjustment to our opening retained earnings was required as a result of the adoption. The presentation and disclosure requirements included in this update were adopted prospectively. Refer to Note 18 for further details.

Accumulated Other Comprehensive Income — Reclassification of Certain Tax Effects (ASU 2018-02)

In February 2018, the FASB issued ASU 2018-02. The amendments in this update provide guidance concerning the treatment of the impact of income tax effects resulting from the Tax Cuts and Jobs Act of 2017 (the Tax Act) on items included in accumulated other comprehensive income. Our policy is to use the portfolio method with respect to reclassification of stranded income tax effects in accumulated other comprehensive loss. The amendments in ASU 2018-02 provide entities an election to reclassify the income tax effect of the Tax Act from accumulated other comprehensive income to retained earnings. We elected to early-adopt this standard as of January 1, 2018, and reclassified the effect of the change in the federal corporate income tax rate on items included in accumulated other comprehensive loss. This election resulted in a reclassification of $42 million from accumulated other comprehensive loss to retained earnings.

Recently Issued Accounting Standards

Leases (ASU 2016-02)

In February 2016, the FASB issued ASU 2016-02. The amendments in this update primarily replace the existing accounting requirements for operating leases for lessees. Lessee accounting requirements for finance leases and lessor accounting requirements for operating leases and sales type and direct financing leases (sales type and direct financing leases were both previously referred to as capital leases) are largely unchanged. The amendments require the lessee of an operating lease to record a balance sheet gross-up upon lease commencement by recognizing a right-of-use asset and lease liability equal to the present value of the lease payments. The right-of-use asset and lease liability should be derecognized in a manner that effectively yields a straight line lease expense over the lease term. In addition to the changes to the lessee operating lease accounting requirements, the amendments also change the types of costs that can be capitalized related to a lease agreement for both lessees and lessors for all types of leases. The amendments also require additional disclosures for all lease types for both lessees and lessors. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied on a modified retrospective basis with a cumulative adjustment to the beginning of the earliest fiscal year presented in the financial statements in the period of adoption. Upon adoption, we expect to record a balance sheet gross-up, reflecting our right-of-use asset and lease liability for our operating leases where we are the lessee (for example, our facility leases). While we are currently reviewing our operating lease contracts where we are the lessee to determine the impact of the gross-up and the changes to capitalizable costs, as well as reviewing our leases where we are the lessor to determine the impact of the changes to capitalizable costs, we do not anticipate the adoption of these amendments will have a material impact to our financial statements. We currently plan to adopt these amendments on January 1, 2019, and expect to use the modified retrospective approach as required.

Financial Instruments — Credit Losses (ASU 2016-13)

In June 2016, the FASB issued ASU 2016-13. The amendments in this update introduce a new accounting model to measure credit losses for financial assets measured at amortized cost. Credit losses for financial assets measured at amortized cost should be determined based on the total current expected credit losses over the life of the financial asset or group of financial assets. In effect, the financial asset or group of financial assets should be presented at the net amount expected to be collected. Credit losses will no longer be recorded under the current incurred loss model for financial assets measured at amortized cost. The amendments also modify the accounting for available-for-sale debt securities whereby credit losses will be recorded through an allowance for credit losses rather than a write-down to the security’s cost basis, which allows for reversals of credit losses when estimated credit losses decline. Credit losses for available-for-sale debt securities should be measured in a manner similar to current GAAP. The amendments are effective on January 1, 2020, with early adoption permitted as of January 1, 2019. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. The new accounting model for credit losses represents a significant departure from existing GAAP, and will likely materially increase the allowance for credit losses with a resulting negative adjustment to retained earnings. Management created a formal working group to govern the implementation of these amendments consisting of key stakeholders from finance, risk, and accounting and is currently evaluating the impact of the amendments. We are in the process of designing and building the models and procedures that will be used to calculate the credit loss reserves in accordance with these amendments. We currently plan to adopt these amendments on January 1, 2020, and expect to use the modified retrospective approach as required.

Receivables — Nonrefundable Fees and Other Costs: Premium Amortization on Purchased Callable Debt Securities (ASU 2017-08)

In March 2017, the FASB issued ASU 2017-08. The amendments in this update require premiums on purchased callable debt securities to be amortized to the security’s earliest call date. Prior to this ASU, premiums and discounts on purchased callable debt securities were generally required to be amortized to the security’s maturity date. The amendments do not require an accounting change for securities held at a discount. The amendments are effective on January 1, 2019, with early adoption permitted. The amendments must be applied using a modified retrospective approach with a cumulative-effect adjustment through retained earnings as of the beginning of the fiscal year upon adoption. While our assessment is not final, we do not expect the amendments to have a material impact to our financial statements. We currently plan to adopt these amendments on January 1, 2019, and expect to use the modified retrospective approach as required.