Basis of Presentation and Accounting Policies Level 2 (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	Future Adoption of New Accounting Standards Hedging Activities In August 2017, the FASB issued updated guidance on hedge accounting. The updates allow hedge accounting for new types of interest rate hedges of financial instruments and simplify documentation requirements to qualify for hedge accounting. In addition, any gain or loss from hedge ineffectiveness will be reported in the same income statement line with the effective hedge results and the hedged transaction. For cash flow hedges, the ineffectiveness will be recognized in earnings only when the hedged transaction affects earnings; otherwise, the ineffectiveness gains or losses will remain in accumulated other comprehensive income (AOCI). Under current accounting, total hedge ineffectiveness is reported separately in realized gains and losses apart from the hedged transaction. The updated guidance is effective January 1, 2019 through a cumulative effect adjustment that will reclassify cumulative ineffectiveness on open cash flow hedges from retained earnings to AOCI. Early adoption is permitted as of the beginning of a year. The Company has not yet determined the timing for adoption or estimated the effect on the Company’s financial statements. Revenue Recognition In May 2014, the FASB issued updated guidance for recognizing revenue. The guidance excludes insurance contracts and financial instruments. Revenue is to be recognized when, or as, goods or services are transferred to customers in an amount that reflects the consideration that an entity is expected to be entitled in exchange for those goods or services, and this accounting guidance is similar to current accounting for many transactions. This guidance is effective retrospectively on January 1, 2018, with a choice of restating prior periods or recognizing a cumulative effect for contracts in place as of the adoption. The Company will adopt on January 1, 2018, and has not determined its method for adoption. Based on current evaluations, the Company will likely present fee income within the Mutual Funds segment gross of related distribution costs that are currently netted against revenues. Fee income has been reported net of distribution costs of $139 and$184 for the nine months ended September 30, 2017, and the year ended December 31, 2016, respectively. The adoption is not expected to have a material effect on the Company’s financial position, cash flows or net income.
Basis of Presentation	The Hartford Financial Services Group, Inc. is a holding company for insurance and financial services subsidiaries that provide property and casualty insurance, group life and disability products and mutual funds and exchange-traded products to individual and business customers in the United States (collectively, “The Hartford”, the “Company”, “we” or “our”). Also, the Company continues to run off life and annuity products previously sold. On May 10, 2017, the Company completed the sale of its United Kingdom ("U.K.") property and casualty run-off subsidiaries. For discussion of this transaction, see Note 2 - Business Disposition of Notes to Condensed Consolidated Financial Statements. The Condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information, which differ materially from the accounting practices prescribed by various insurance regulatory authorities. These Condensed Consolidated Financial Statements and Notes should be read in conjunction with the Consolidated Financial Statements and Notes thereto included in the Company's 2016 Form 10-K Annual Report. The results of operations for interim periods are not necessarily indicative of the results that may be expected for the full year. The accompanying Condensed Consolidated Financial Statements and Notes are unaudited. These financial statements reflect all adjustments (generally consisting only of normal accruals) which are, in the opinion of management, necessary for the fair presentation of the financial position, results of operations and cash flows for the interim periods. The Company's significant accounting policies are summarized in Note 1 - Basis of Presentation and Significant Accounting Policies of Notes to Consolidated Financial Statements included in the Company's 2016 Form 10-K Annual Report.
Consolidation	Consolidation The Condensed Consolidated Financial Statements include the accounts of The Hartford Financial Services Group, Inc., and entities in which the Company directly or indirectly has a controlling financial interest. Entities in which the Company has significant influence over the operating and financing decisions but does not control are reported using the equity method. All intercompany transactions and balances between The Hartford and its subsidiaries and affiliates have been eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements, in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The most significant estimates include those used in determining property and casualty and group long-term disability (LTD) insurance product reserves, net of reinsurance; estimated gross profits used in the valuation and amortization of assets and liabilities associated with variable annuity and other universal life-type contracts; living benefits required to be fair valued; evaluation of goodwill for impairment; valuation of investments and derivative instruments, including evaluation of other-than-temporary impairments on available-for-sale securities; valuation allowance on deferred tax assets; and contingencies relating to corporate litigation and regulatory matters. Certain of these estimates are particularly sensitive to market conditions, and deterioration and/or volatility in the worldwide debt or equity markets could have a material impact on the Condensed Consolidated Financial Statements.
Reclassification, Policy	Reclassifications Certain reclassifications have been made to prior year financial information to conform to the current year presentation. In particular, billing installment fees that were previously reflected as an offset to insurance operating costs and other expenses are now classified as revenues.
Adoption of New Accounting Standards	Adoption of New Accounting Standards Stock Compensation On January 1, 2017 the Company adopted new stock compensation guidance issued by the Financial Accounting Standards Board ("FASB") on a prospective basis. The updated guidance requires the excess tax benefit or tax deficiency on vesting or settlement of stock-based awards to be recognized in earnings as an income tax benefit or expense, respectively, instead of as an adjustment to additional paid-in capital. The new guidance also requires the related cash flows to be presented in operating activities instead of in financing activities. The amount of excess tax benefit or tax deficiency realized on vesting or settlement of awards depends upon the difference between the market value of awards at vesting or settlement and the grant date fair value recognized through compensation expense. The excess tax benefit or tax deficiency is a discrete item in the reporting period in which it occurs and is not considered in determining the annual estimated effective tax rate for interim reporting.