Income Taxes	9 Months Ended
Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes Income Tax Provision In accordance with the applicable accounting guidance, the principal method established for computing the provision for income taxes in interim periods requires us to make our best estimate of the effective tax rate expected to be applicable for the full year. This estimated effective tax rate is then applied to interim consolidated pre-tax operating income to determine the interim provision for income taxes. The effective tax rate, which is the provision for income taxes as a percentage of income from continuing operations before income taxes, was 9.1% for the third quarter of 2016 and 24.4% for the third quarter of 2015. The effective tax rates are below our combined federal and state statutory tax rate of 37.2% primarily due to income from investments in tax-advantaged assets such as corporate-owned life insurance and credits associated with renewable energy and low-income housing investments. The tax rate for the third quarter of 2016 was also significantly reduced due to merger and integration expenses of $207 million. Excluding those expenses, the tax rate for the third quarter of 2016 was 23.4%. Deferred Tax Asset At September 30, 2016, from continuing operations, we had a net deferred tax asset of $488 million, compared to a net deferred tax asset of $95 million at December 31, 2015, and a net deferred tax asset of $216 million at September 30, 2015, included in “accrued income and other assets” on the balance sheet. At September 30, 2016, deferred tax assets were impacted by the First Niagara acquisition including certain purchase accounting adjustments and changes in market conditions that impact the mark to market deferred tax adjustment on securities. To determine the amount of deferred tax assets that are more-likely-than-not to be realized, and therefore recorded, we conduct a quarterly assessment of all available evidence. This evidence includes, but is not limited to, taxable income in prior periods, projected future taxable income, and projected future reversals of deferred tax items. These assessments involve a degree of subjectivity and may undergo change. Based on these criteria, we had a valuation allowance of $35 million at September 30, 2016, and less than $1 million at both December 31, 2015, and September 30, 2015. The valuation allowance is associated with certain state net operating loss carryforwards, state credit carryforwards, and federal and state capital loss carryforwards. The $35 million increase in the valuation allowance at September 30, 2016, is attributable to federal and state capital loss carryforwards acquired in the First Niagara acquisition. Unrecognized Tax Benefits As permitted under the applicable accounting guidance for income taxes, it is our policy to recognize interest and penalties related to unrecognized tax benefits in income tax expense. At September 20, 2016, Key's unrecognized tax benefits were $48 million. Unrecognized tax benefits acquired in the First Niagara acquisition were $28 million. Pre-1988 Bank Reserves acquired in a business combination In connection with the First Niagara acquisition, at September 30, 2016, the retained earnings of First Niagara Bank had approximately $92 million of allocated bad debt deductions for which no income taxes have been recorded. Under current federal law, these reserves are subject to recapture into taxable income if First Niagara Bank, or any successor, fails to maintain its bank status under the Internal Revenue Code or makes non-dividend distributions or distributions greater than its accumulated earnings and profits. No deferred tax liability has been established as these events are not expected to occur in the foreseeable future.

11. Income Taxes

Income Tax Provision

In accordance with the applicable accounting guidance, the principal method established for computing the provision for income taxes in interim periods requires us to make our best estimate of the effective tax rate expected to be applicable for the full year. This estimated effective tax rate is then applied to interim consolidated pre-tax operating income to determine the interim provision for income taxes.

The effective tax rate, which is the provision for income taxes as a percentage of income from continuing operations before income taxes, was 9.1% for the third quarter of 2016 and 24.4% for the third quarter of 2015. The effective tax rates are below our combined federal and state statutory tax rate of 37.2% primarily due to income from investments in tax-advantaged assets such as corporate-owned life insurance and credits associated with renewable energy and low-income housing investments. The tax rate for the third quarter of 2016 was also significantly reduced due to merger and integration expenses of $207 million. Excluding those expenses, the tax rate for the third quarter of 2016 was 23.4%.

Deferred Tax Asset

At September 30, 2016, from continuing operations, we had a net deferred tax asset of $488 million, compared to a net deferred tax asset of $95 million at December 31, 2015, and a net deferred tax asset of $216 million at September 30, 2015, included in “accrued income and other assets” on the balance sheet. At September 30, 2016, deferred tax assets were impacted by the First Niagara acquisition including certain purchase accounting adjustments and changes in market conditions that impact the mark to market deferred tax adjustment on securities.

To determine the amount of deferred tax assets that are more-likely-than-not to be realized, and therefore recorded, we conduct a quarterly assessment of all available evidence. This evidence includes, but is not limited to, taxable income in prior periods, projected future taxable income, and projected future reversals of deferred tax items. These assessments involve a degree of subjectivity and may undergo change. Based on these criteria, we had a valuation allowance of $35 million at September 30, 2016, and less than $1 million at both December 31, 2015, and September 30, 2015. The valuation allowance is associated with certain state net operating loss carryforwards, state credit carryforwards, and federal and state capital loss carryforwards. The $35 million increase in the valuation allowance at September 30, 2016, is attributable to federal and state capital loss carryforwards acquired in the First Niagara acquisition.

Unrecognized Tax Benefits

As permitted under the applicable accounting guidance for income taxes, it is our policy to recognize interest and penalties related to unrecognized tax benefits in income tax expense.

At September 20, 2016, Key's unrecognized tax benefits were $48 million. Unrecognized tax benefits acquired in the First Niagara acquisition were $28 million.

Pre-1988 Bank Reserves acquired in a business combination

In connection with the First Niagara acquisition, at September 30, 2016, the retained earnings of First Niagara Bank had approximately $92 million of allocated bad debt deductions for which no income taxes have been recorded. Under current federal law, these reserves are subject to recapture into taxable income if First Niagara Bank, or any successor, fails to maintain its bank status under the Internal Revenue Code or makes non-dividend distributions or distributions greater than its accumulated earnings and profits. No deferred tax liability has been established as these events are not expected to occur in the foreseeable future.