Commitments and Contingencies Level 1 (Notes)	6 Months Ended
Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Litigation The Hartford is involved in claims litigation arising in the ordinary course of business, both as a liability insurer defending or providing indemnity for third-party claims brought against insureds and as an insurer defending coverage claims brought against it. The Hartford accounts for such activity through the establishment of unpaid loss and loss adjustment expense reserves. Subject to the uncertainties in the following discussion under the caption “Asbestos and Environmental Claims,” management expects that the ultimate liability, if any, with respect to such ordinary-course claims litigation, after consideration of provisions made for potential losses and costs of defense, will not be material to the consolidated financial condition, results of operations or cash flows of The Hartford. The Hartford is also involved in other kinds of legal actions, some of which assert claims for substantial amounts. These actions include, among others, and in addition to the matters in the following discussion, putative state and federal class actions seeking certification of a state or national class. Such putative class actions have alleged, for example, underpayment of claims or improper underwriting practices in connection with various kinds of insurance policies, such as personal and commercial automobile, property, disability, life and inland marine. The Hartford also is involved in individual actions in which punitive damages are sought, such as claims alleging bad faith in the handling of insurance claims or other allegedly unfair or improper business practices. Like many other insurers, The Hartford also has been joined in actions by asbestos plaintiffs asserting, among other things, that insurers had a duty to protect the public from the dangers of asbestos and that insurers committed unfair trade practices by asserting defenses on behalf of their policyholders in the underlying asbestos cases. Management expects that the ultimate liability, if any, with respect to such lawsuits, after consideration of provisions made for estimated losses, will not be material to the consolidated financial condition of The Hartford. Nonetheless, given the large or indeterminate amounts sought in certain of these actions, and the inherent unpredictability of litigation, the outcome in certain matters could, from time to time, have a material adverse effect on the Company’s results of operations or cash flows in particular quarterly or annual periods. In addition to the inherent difficulty of predicting litigation outcomes, the Mutual Funds Litigation identified below purports to seek substantial damages for unsubstantiated conduct spanning a multi-year period based on novel applications of complex legal theories. The alleged damages are not quantified or factually supported in the complaint, and, in any event, the Company’s experience shows that demands for damages often bear little relation to a reasonable estimate of potential loss. The application of the legal standard identified by the court for assessing the potentially available damages, as described below, is inherently unpredictable, and no legal precedent has been identified that would aid in determining a reasonable estimate of potential loss. Accordingly, management cannot reasonably estimate the possible loss or range of loss, if any. Mutual Funds Litigation — In February 2011, a derivative action was brought on behalf of six Hartford retail mutual funds in the United States District Court for the District of New Jersey, alleging that Hartford Investment Financial Services, LLC (“HIFSCO”), an indirect subsidiary of the Company, received excessive advisory and distribution fees in violation of its statutory fiduciary duty under Section 36(b) of the Investment Company Act of 1940. During the course of the litigation, the claims regarding distribution fees were dismissed without prejudice, the lineup of funds as plaintiffs changed several times, and the plaintiffs added as a defendant Hartford Funds Management Company (“HFMC”), an indirect subsidiary of the Company that assumed the role of advisor to the funds as of January 2013. In June 2015, HFMC and HIFSCO moved for summary judgment, and plaintiffs cross-moved for partial summary judgment with respect to one fund. In March 2016, the court denied the plaintiff's motion, and granted summary judgment for HIFSCO and HFMC with respect to one fund, leaving six funds as plaintiffs: The Hartford Balanced Fund, The Hartford Capital Appreciation Fund, The Hartford Floating Rate Fund, The Hartford Growth Opportunities Fund, The Hartford Healthcare Fund, and The Hartford Inflation Plus Fund. The court further ruled that the appropriate measure of damages on the surviving claims would be the difference, if any, between the actual advisory fees paid through trial and the fees permitted under the applicable legal standard. A bench trial on the issue of liability was held in November 2016. In February 2017, the court granted judgment for HIFSCO and HFMC as to all claims. Plaintiffs have appealed to the United States Court of Appeals for the Third Circuit. Asbestos and Environmental Claims –The Company continues to receive asbestos and environmental claims. Asbestos claims relate primarily to bodily injuries asserted by people who came in contact with asbestos or products containing asbestos. Environmental claims relate primarily to pollution and related clean-up costs. The Company principally relies on exposure-based analysis to estimate the ultimate costs of these claims, both gross and net of reinsurance, and regularly evaluates new account information in assessing its potential asbestos and environmental exposures. The Company supplements this exposure-based analysis with evaluations of the Company’s historical direct net loss and expense paid and reported experience, and net loss and expense paid and reported experience by calendar and/or report year. While the Company believes that its current asbestos and environmental reserves are appropriate, significant uncertainties limit the ability of insurers and reinsurers to estimate the ultimate reserves necessary for unpaid losses and related expenses. The ultimate liabilities, thus, could exceed the currently recorded reserves, and any such additional liability, while not reasonably estimable now, could be material to The Hartford’s consolidated operating results and liquidity. Under an adverse development cover (“ADC”) reinsurance agreement with National Indemnity Company (“NICO”), a subsidiary of Berkshire Hathaway Inc., the Company paid $650 to reinsure adverse development of net asbestos and environmental loss and allocated loss adjustment expense reserves of up to $1.5 billion above the Company’s net asbestos and environmental reserves as of December 31, 2016 of approximately $1.7 billion. Under retroactive reinsurance accounting, net adverse asbestos and environmental reserve development after December 31, 2016, if any, will result in an offsetting reinsurance recoverable up to the $1.5 billion limit. Cumulative ceded losses up to the $650 reinsurance premium paid would be recognized as a dollar-for-dollar offset to direct losses incurred. Cumulative ceded losses exceeding the $650 reinsurance premium paid would result in a deferred gain. The deferred gain would be recognized over the claim settlement period in the proportion of the amount of cumulative ceded losses collected from the reinsurer to the estimated ultimate reinsurance recoveries. Consequently, until periods when the deferred gain is recognized as a benefit to earnings, cumulative adverse development of asbestos and environmental claims after December 31, 2016 in excess of $650 may result in significant charges against earnings. Furthermore, there is a risk that cumulative adverse development of asbestos and environmental claims could ultimately exceed the $1.5 billion treaty limit in which case all adverse development in excess of the treaty limit would be absorbed as a charge to earnings by the Company. In these scenarios, the effect of these changes could be material to the Company’s consolidated operating results and liquidity. Derivative Commitments Certain of the Company’s derivative agreements contain provisions that are tied to the financial strength ratings, as set by nationally recognized statistical agencies, of the individual legal entity that entered into the derivative agreement. If the legal entity’s financial strength were to fall below certain ratings, the counterparties to the derivative agreements could demand immediate and ongoing full collateralization and in certain instances enable the counterparties to terminate the agreements and demand immediate settlement of all outstanding derivative positions traded under each impacted bilateral agreement. The settlement amount is determined by netting the derivative positions transacted under each agreement. If the termination rights were to be exercised by the counterparties, it could impact the legal entity’s ability to conduct hedging activities by increasing the associated costs and decreasing the willingness of counterparties to transact with the legal entity. The aggregate fair value of all derivative instruments with credit-risk-related contingent features that are in a net liability position as of June 30, 2017 was $1.3 billion. For this $1.3 billion, the legal entities have posted collateral of $897 in the normal course of business. In addition, the Company has posted collateral of $31 associated with a customized GMWB derivative. Based on derivative market values as of June 30, 2017 a downgrade of one level below the current financial strength ratings by either Moody’s or S&P would not require additional assets to be posted as collateral. Based on derivative market values as of June 30, 2017, a downgrade of two levels below the current financial strength ratings by either Moody's or S&P would require additional $9 of assets to be posted as collateral. These collateral amounts could change as derivative market values change, as a result of changes in our hedging activities or to the extent changes in contractual terms are negotiated. The nature of the collateral that we post, when required, is primarily in the form of U.S. Treasury bills, U.S. Treasury notes and government agency securities.

Litigation

The Hartford is involved in claims litigation arising in the ordinary course of business, both as a liability insurer defending or providing indemnity for third-party claims brought against insureds and as an insurer defending coverage claims brought against it. The Hartford accounts for such activity through the establishment of unpaid loss and loss adjustment expense reserves. Subject to the uncertainties in the following discussion under the caption “Asbestos and Environmental Claims,” management expects that the ultimate liability, if any, with respect to such ordinary-course claims litigation, after consideration of provisions made for potential losses and costs of defense, will not be material to the consolidated financial condition, results of operations or cash flows of The Hartford.

The Hartford is also involved in other kinds of legal actions, some of which assert claims for substantial amounts. These actions include, among others, and in addition to the matters in the following discussion, putative state and federal class actions seeking certification of a state or national class. Such putative class actions have alleged, for example, underpayment of claims or improper underwriting practices in connection with various kinds of insurance policies, such as personal and commercial automobile, property, disability, life and inland marine. The Hartford also is involved in individual actions in which punitive damages are sought, such as claims alleging bad faith in the handling of insurance claims or other allegedly unfair or improper business practices. Like many other insurers, The Hartford also has been joined in actions by asbestos plaintiffs asserting, among other things, that insurers had a duty to protect the public from the dangers of asbestos and that insurers committed unfair trade practices by asserting defenses on behalf of their policyholders in the underlying asbestos cases. Management expects that the ultimate liability, if any, with respect to such lawsuits, after consideration of provisions made for estimated losses, will not be material to the consolidated financial condition of The Hartford. Nonetheless, given the large or indeterminate amounts sought in certain of these actions, and the inherent unpredictability of litigation, the outcome in certain matters could, from time to time, have a material adverse effect on the Company’s results of operations or cash flows in particular quarterly or annual periods.

In addition to the inherent difficulty of predicting litigation outcomes, the Mutual Funds Litigation identified below purports to seek substantial damages for unsubstantiated conduct spanning a multi-year period based on novel applications of complex legal theories. The alleged damages are not quantified or factually supported in the complaint, and, in any event, the Company’s experience shows that demands for damages often bear little relation to a reasonable estimate of potential loss. The application of the legal standard identified by the court for assessing the potentially available damages, as described below, is inherently unpredictable, and no legal precedent has been identified that would aid in determining a reasonable estimate of potential loss. Accordingly, management cannot reasonably estimate the possible loss or range of loss, if any.

Mutual Funds Litigation — In February 2011, a derivative action was brought on behalf of six Hartford retail mutual funds in the United States District Court for the District of New Jersey, alleging that Hartford Investment Financial Services, LLC (“HIFSCO”), an indirect subsidiary of the Company, received excessive advisory and distribution fees in violation of its statutory fiduciary duty under Section 36(b) of the Investment Company Act of 1940. During the course of the litigation, the claims regarding distribution fees were dismissed without prejudice, the lineup of funds as plaintiffs changed several times, and the plaintiffs added as a defendant Hartford Funds Management Company (“HFMC”), an indirect subsidiary of the Company that assumed the role of advisor to the funds as of January 2013. In June 2015, HFMC and HIFSCO moved for summary judgment, and plaintiffs cross-moved for partial summary judgment with respect to one fund. In March 2016, the court denied the plaintiff's motion, and granted summary judgment for HIFSCO and HFMC with respect to one fund, leaving six funds as plaintiffs: The Hartford Balanced Fund, The Hartford Capital Appreciation Fund, The Hartford Floating Rate Fund, The Hartford Growth Opportunities Fund, The Hartford Healthcare Fund, and The Hartford Inflation Plus Fund. The court further ruled that the appropriate measure of damages on the surviving claims would be the difference, if any, between the actual advisory fees paid through trial and the fees permitted under the applicable legal standard. A bench trial on the issue of liability was held in November 2016. In February 2017, the court granted judgment for HIFSCO and HFMC as to all claims. Plaintiffs have appealed to the United States Court of Appeals for the Third Circuit.

Asbestos and Environmental Claims –The Company continues to receive asbestos and environmental claims. Asbestos claims relate primarily to bodily injuries asserted by people who came in contact with asbestos or products containing asbestos. Environmental claims relate primarily to pollution and related clean-up costs.

The Company principally relies on exposure-based analysis to estimate the ultimate costs of these claims, both gross and net of reinsurance, and regularly evaluates new account information in assessing its potential asbestos and environmental exposures. The Company supplements this exposure-based analysis with evaluations of the Company’s historical direct net loss and expense paid and reported experience, and net loss and expense paid and reported experience by calendar and/or report year.

While the Company believes that its current asbestos and environmental reserves are appropriate, significant uncertainties limit the ability of insurers and reinsurers to estimate the ultimate reserves necessary for unpaid losses and related expenses. The ultimate liabilities, thus, could exceed the currently recorded reserves, and any such additional liability, while not reasonably estimable now, could be material to The Hartford’s consolidated operating results and liquidity.

Under an adverse development cover (“ADC”) reinsurance agreement with National Indemnity Company (“NICO”), a subsidiary of Berkshire Hathaway Inc., the Company paid $650 to reinsure adverse development of net asbestos and environmental loss and allocated loss adjustment expense reserves of up to $1.5 billion above the Company’s net asbestos and environmental reserves as of December 31, 2016 of approximately $1.7 billion.

Under retroactive reinsurance accounting, net adverse asbestos and environmental reserve development after December 31, 2016, if any, will result in an offsetting reinsurance recoverable up to the $1.5 billion limit. Cumulative ceded losses up to the $650 reinsurance premium paid would be recognized as a dollar-for-dollar offset to direct losses incurred. Cumulative ceded losses exceeding the $650 reinsurance premium paid would result in a deferred gain. The deferred gain would be recognized over the claim settlement period in the proportion of the amount of cumulative ceded losses collected from the reinsurer to the estimated ultimate reinsurance recoveries. Consequently, until periods when the deferred gain is recognized as a benefit to earnings, cumulative adverse development of asbestos and environmental claims after December 31, 2016 in excess of $650 may result in significant charges against earnings. Furthermore, there is a risk that cumulative adverse development of asbestos and environmental claims could ultimately exceed the $1.5 billion treaty limit in which case all adverse development in excess of the treaty limit would be absorbed as a charge to earnings by the Company. In these scenarios, the effect of these changes could be material to the Company’s consolidated operating results and liquidity.

Derivative Commitments

Certain of the Company’s derivative agreements contain provisions that are tied to the financial strength ratings, as set by nationally recognized statistical agencies, of the individual legal entity that entered into the derivative agreement. If the legal entity’s financial strength were to fall below certain ratings, the counterparties to the derivative agreements could demand immediate and ongoing full collateralization and in certain instances enable the counterparties to terminate the agreements and demand immediate settlement of all outstanding derivative positions traded under each impacted bilateral agreement. The settlement amount is determined by netting the derivative positions transacted under each agreement. If the termination rights were to be exercised by the counterparties, it could impact the legal entity’s ability to conduct hedging activities by increasing the associated costs and decreasing the willingness of counterparties to transact with the legal entity. The aggregate fair value of all derivative instruments with credit-risk-related contingent features that are in a net liability position as of June 30, 2017 was $1.3 billion. For this $1.3 billion, the legal entities have posted collateral of $897 in the normal course of business. In addition, the Company has posted collateral of $31 associated with a customized GMWB derivative. Based on derivative market values as of June 30, 2017 a downgrade of one level below the current financial strength ratings by either Moody’s or S&P would not require additional assets to be posted as collateral. Based on derivative market values as of June 30, 2017, a downgrade of two levels below the current financial strength ratings by either Moody's or S&P would require additional $9 of assets to be posted as collateral. These collateral amounts could change as derivative market values change, as a result of changes in our hedging activities or to the extent changes in contractual terms are negotiated. The nature of the collateral that we post, when required, is primarily in the form of U.S. Treasury bills, U.S. Treasury notes and government agency securities.