Organization, Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization (policy)	Organization ETRADE Financial Corporation is a financial services company that provides brokerage and related products and services primarily to individual retail investors under the brand ETRADE Financial. The Company also provides investor-focused banking products, primarily sweep deposits, to retail investors.
Basis of presentation (policy)	Basis of Presentation The condensed consolidated financial statements, also referred to herein as the consolidated financial statements, include the accounts of the Company and its majority-owned subsidiaries as determined under the voting interest model. Entities in which the Company has the ability to exercise significant influence but in which the Company does not possess control are generally accounted for by the equity method. Entities in which the Company does not have the ability to exercise significant influence are generally carried at cost. Investments in marketable equity securities where the Company does not have the ability to exercise significant influence over the entities are accounted for as available-for-sale equity securities. The Company also evaluates its initial and continuing involvement with certain entities to determine if the Company is required to consolidate the entities under the variable interest entity (VIE) model. This evaluation is based on a qualitative assessment of whether the Company is the primary beneficiary of the VIE, which requires the Company to possess both: 1) the power to direct the activities that most significantly impact the economic performance of the VIE; and 2) the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to the VIE. The consolidated financial statements do not include any consolidated VIEs for all periods presented. The Company's consolidated financial statements are prepared in accordance with GAAP. Intercompany accounts and transactions are eliminated in consolidation. These financial statements reflect all adjustments, which are normal and recurring in nature, necessary to present fairly the financial position, results of operations and cash flows for the periods presented. These consolidated financial statements should be read in conjunction with the Annual Report on Form 10-K for the year ended December 31, 2016. While certain disclosures included in annual financial statements prepared in accordance with GAAP have been omitted in this quarterly report, the Company believes that the information and disclosures presented herein are adequate and that such disclosures are not misleading.
Use of estimates (policy)	Use of Estimates Preparing the Company's consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and related notes for the periods presented. Actual results could differ from management’s estimates. Certain significant accounting policies are critical because they are based on estimates and assumptions that require complex and subjective judgments by management. Changes in these estimates or assumptions could materially impact the Company’s financial condition and results of operations. Material estimates in which management believes changes could reasonably occur include: allowance for loan losses; valuation and impairment of goodwill and acquired intangible assets; and estimates of effective tax rates, deferred taxes and valuation allowance.
New accounting and disclosure guidance (policy)	Adoption of New Accounting Standards Accounting for Employee Share-Based Payments In March 2016, the FASB amended the accounting guidance on employee share-based payments. Relevant changes in the amended guidance include the requirement to recognize all excess tax benefits and deficiencies upon exercise or vesting as income tax expense or benefit in the consolidated statement of income; to treat excess tax benefits and deficiencies as discrete items in the reporting period they occur; to not delay recognition of excess tax benefits until the tax benefit is realized through a reduction in current taxes payable; and to make an accounting policy election to either estimate forfeitures or account for them as they occur. The Company adopted the amended accounting guidance as of January 1, 2017 and recognized a $3 million deferred tax asset and cumulative-effect adjustment to equity as of the beginning of the period. In addition, for the six months ended June 30, 2016 the Company reclassified $13 million related to shares withheld to pay taxes from cash flows from operating activities to cash flows from financing activities. Forfeitures will continue to be estimated consistent with the Company's prior accounting policies. The impact to the Company's financial condition, results of operations and cash flows will vary based on, among other factors, the market price of the Company's common stock. During the six months ended June 30, 2017 the Company recognized a $6 million income tax benefit in accordance with the new guidance. New Accounting Standards Not Yet Adopted Revenue Recognition on Contracts with Customers In May 2014, the FASB amended the guidance on revenue recognition on contracts with customers. The new standard outlines a single comprehensive model for entities to apply in accounting for revenue arising from contracts with customers. The Company's accounting for net interest income is not expected to be impacted by the new standard. The FASB issued supplemental amendments to the new standard to clarify certain accounting guidance and provide narrow scope improvements and practical expedients during 2016. The amended guidance will be effective for annual and interim periods beginning on January 1, 2018 and may be applied on either a full retrospective or modified retrospective basis. The Company is in process of completing its evaluation of the new accounting guidance. This adoption is not expected to have a material impact on the Company’s financial condition, results of operations or cash flows as the satisfaction of performance obligations under the new guidance is expected to be materially consistent with the Company's existing revenue recognition policies. Similarly, the amended guidance is not expected to have a material impact on the recognition of costs incurred to obtain new contracts. Classification and Measurement of Financial Instruments In January 2016, the FASB amended the accounting and disclosure guidance on the classification and measurement of financial instruments. Relevant changes in the amended guidance include the requirement that equity investments, excluding those accounted for under the equity method of accounting or those resulting in consolidation of the investee, be measured at fair value in the consolidated balance sheet with changes in fair value recognized in net income. For disclosure purposes, the Company will no longer be required to disclose the methods and significant assumptions used to estimate fair value for financial instruments measured at amortized cost in the consolidated balance sheet. The amended guidance will be effective for interim and annual periods beginning on January 1, 2018 and is required to be applied on a modified retrospective basis by means of a cumulative-effect adjustment to the consolidated balance sheet on that date. The Company is currently evaluating the impact of the new accounting guidance; however, the adoption is not expected to have a material impact on the Company’s financial condition, results of operations or cash flows as debt securities represent the majority of the Company's investment portfolio. Accounting for Leases In February 2016, the FASB amended the guidance on accounting for leases. The new standard requires lessees to recognize assets and liabilities on the balance sheet for the rights and obligations created by all qualifying leases with terms of more than twelve months. The recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee remains substantially unchanged and depends on classification as a finance or operating lease. The new standard also requires quantitative and qualitative disclosures that provide information about the amounts related to leasing arrangements recorded in the consolidated financial statements. The new guidance will be effective for interim and annual periods beginning on January 1, 2019 and is required to be applied on a modified retrospective basis to the earliest period presented, which includes practical expedient options in certain circumstances. The Company is currently evaluating the impact of the new accounting guidance on the Company's financial condition, results of operations and cash flows; however, the Company's business model of providing services through digital platforms and via phone and online channels in addition to 30 regional branches may limit the impact of the amended lease accounting guidance to the Company's financial condition. Accounting for Credit Losses In June 2016, the FASB amended the accounting guidance on accounting for credit losses. The amended guidance requires measurement of all expected credit losses for financial instruments and other commitments to extend credit held at the reporting date. For financial assets measured at amortized cost, factors such as historical experience, current conditions, and reasonable and supportable forecasts will be used to estimate expected credit losses. The amended guidance will also change the manner in which credit losses are recognized on debt securities classified as available-for-sale. The new guidance will be effective for interim and annual periods beginning January 1, 2020. Early adoption is permitted. The Company is currently evaluating the impact of the new accounting guidance on the Company's financial condition, results of operations and cash flows; however, given the recent performance of the Company's run-off legacy loan portfolio and the credit profile of the current investment securities portfolio, the Company does not expect the amended accounting guidance to have as significant of an impact as it could have if the Company were originating or purchasing loans. Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB amended the guidance on the presentation and classification of certain cash receipts and cash payments in the consolidated statement of cash flows to eliminate current diversity in practice. The new guidance will be effective for interim and annual periods beginning January 1, 2018 and must be applied using a retrospective transition method to each period presented. Early adoption is permitted. The Company does not expect the amended accounting guidance to have a significant impact on its consolidated statement of cash flows. Classification of Restricted Cash In November 2016, the FASB amended the guidance on the presentation and classification of changes in restricted cash in the consolidated statement of cash flows to eliminate current diversity in practice. The amended guidance requires the consolidated statement of cash flows to explain the change during the period in the total cash, cash equivalents, and amounts generally described as restricted cash and restricted cash equivalents. The guidance will be effective for interim and annual periods beginning January 1, 2018 and must be applied using a retrospective transition method to each period presented. Early adoption is permitted. The Company is currently evaluating the impact of the new presentation and classification guidance. Clarifying the Definition of a Business In January 2017, the FASB issued guidance to clarify the definition of a business in order to assist companies in the evaluation of whether transactions should be accounted for as acquisitions or disposals of assets or businesses. The amended guidance also removes the existing evaluation of a market participant's ability to replace missing elements and narrows the definition of output to achieve consistency with other topics. The guidance will be effective for interim and annual periods beginning January 1, 2018 and must be applied prospectively. Early adoption is permitted. Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued guidance to simplify the test for goodwill impairment by eliminating Step 2 from the goodwill impairment test. The amended guidance requires the Company to perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized at the amount by which the carrying amount exceeds the fair value of the reporting unit; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Income tax effects resulting from any tax deductible goodwill should be considered when measuring the goodwill impairment loss, if applicable. The Company will still have the option to perform a qualitative assessment to conclude whether it is more likely than not that the carrying amount of the Company exceeds its fair value. The guidance will be effective for interim and annual periods beginning January 1, 2020 and must be applied prospectively. Early adoption is permitted. Premium Amortization on Purchased Callable Debt Securities In March 2017, the FASB issued guidance to amend the amortization period for certain purchased callable debt securities held at a premium. The amended guidance shortens the amortization period for certain callable debt securities held at a premium by requiring the premium to be amortized to the earliest call date. The guidance does not amend the accounting for securities held at a discount. The guidance will be effective for interim and annual periods beginning January 1, 2019 and must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. Early adoption is permitted. Based on the current composition of the Company's securities portfolio, the new guidance is not expected to have a significant impact on the Company's financial condition or results of operations.