Variable Interest Entities	6 Months Ended
Variable Interest Entities	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities The Company has an investment interest in several entities that meet the definition of a VIE. The following discussion provides information about the Company's VIEs. Consolidated Rabbi Trust. The Company established a Rabbi Trust to meet the obligations due under its Deferred Compensation Plan for Directors and Officers and to mitigate the expense volatility of the aforementioned plan. The funding of the Rabbi Trust and the discontinuation of the Deferred Compensation Plan for Directors and Officers occurred during 2012. Investments held in the Rabbi Trust primarily consist of mutual funds that invest in equity and fixed income securities. The Company is considered the primary beneficiary of the Rabbi Trust as it has the power to direct the activities of the Rabbi Trust that significantly affect the VIE's economic performance and it has the obligation to absorb losses of the VIE that could potentially be significant to the VIE. The Company consolidates the invested assets of the trust along with the total deferred compensation obligations and includes them in accrued interest receivable and other assets and accrued expenses and other liabilities, respectively, in the accompanying Condensed Consolidated Balance Sheets. Earnings in the Rabbi Trust, including appreciation or depreciation, are reflected as other non-interest income, and changes in the corresponding liability are reflected as compensation and benefits, in the accompanying Condensed Consolidated Statements of Income. Non-Consolidated Securitized Investments. The Company, through normal investment activities, makes passive investments in securities issued by VIEs for which Webster is not the manager. The investment securities consist of Agency CMO, Agency MBS, Agency CMBS, CLO and trust preferred. The Company has not provided financial or other support with respect to these investment securities other than its original investment. For these investment securities, the Company determined it is not the primary beneficiary due to the relative size of its investment in comparison to the principal amount of the structured securities issued by the VIEs, the level of credit subordination which reduces the Company’s obligation to absorb losses or right to receive benefits and its inability to direct the activities that most significantly impact the economic performance of the VIEs. The Company’s maximum exposure to loss is limited to the amount of its investment in the VIEs. Refer to Note 2: Investment Securities for additional information. Tax Credit - Finance Investments. The Company makes equity investments in entities that finance affordable housing and other community development projects and provide a return primarily through the realization of tax benefits. In most instances the investments require the funding of capital commitments in the future. While the Company's investment in an entity may exceed 50% of its outstanding equity interests, the entity is not consolidated as Webster is not involved in its management. For these investments, the Company determined it is not the primary beneficiary due to its inability to direct the activities that most significantly impact the economic performance of the VIEs. At June 30, 2017 and December 31, 2016, the aggregate carrying value of the Company's tax credit-finance investments were$29.2 million and $22.8 million, respectively. At June 30, 2017 and December 31, 2016, unfunded commitments have been recognized, totaling $20.4 million and $14.0 million, respectively, and are included in accrued expenses and other liabilities in the accompanying Condensed Consolidated Balance Sheets. Webster Statutory Trust. The Company owns all of the outstanding common stock of Webster Statutory Trust, which is a financial vehicle that has issued, and may issue in the future, trust preferred securities. The trust is a VIE in which the Company is not the primary beneficiary and therefore, is not consolidated. The trust's only assets are junior subordinated debentures issued by the Company, which were acquired by the trust using the proceeds from the issuance of the trust preferred securities and common stock. The junior subordinated debentures are included in long-term debt in the accompanying Condensed Consolidated Balance Sheets, and the related interest expense is reported as interest expense on long-term debt in the accompanying Condensed Consolidated Statements of Income. Other Investments. The Company invests in various alternative investments in which it holds a variable interest. Alternative investments are non-public entities which cannot be redeemed since the Company’s investment is distributed as the underlying equity is liquidated. For these investments, the Company has determined it is not the primary beneficiary due to its inability to direct the activities that most significantly impact the economic performance of the VIEs. At June 30, 2017 and December 31, 2016, the aggregate carrying value of the Company's other investments in VIEs were $12.2 million and $12.3 million, respectively, and the total exposure of the Company's other investments in VIEs, including unfunded commitments, were $21.3 million and $19.9 million, respectively. The Company's equity interests in Tax Credit-Finance Investments, Webster Statutory Trust, and Other Investments are included in accrued interest receivable and other assets in the accompanying Condensed Consolidated Balance Sheets. For a further description of the Company's accounting policies regarding the consolidation of a VIE, refer to Note 1 to the Consolidated Financial Statements for the year ended December 31, 2016 included in its 2016 Form 10-K.