Income Taxes	3 Months Ended
Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	10. 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 24.4% for the first quarter of 2015 and 27.8% for the first quarter of 2014. 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 investments in low-income housing projects. In addition, during the first quarter of 2015, our effective tax rate was reduced by additional federal tax credit refunds filed for prior years. Deferred Tax Asset At March 31, 2015, from continuing operations, we had a net federal deferred tax asset of $88 million and a net state deferred tax asset of $13 million compared to a net federal deferred tax asset of $174 million and a net state deferred tax asset of $20 million at December 31, 2014, and a net federal deferred tax asset of $148 million and a net state deferred tax asset of $4 million at March 31, 2014, included in “accrued income and other assets” on the balance sheet. 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 less than $1 million at March 31, 2015, and at December 31, 2014, and $1 million at March 31, 2014, associated with certain state net operating loss carryforwards and state credit carryforwards. 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. Deferred tax assets were reduced in the financial statements for unrecognized tax benefits by $1 million at March 31, 2015, December 31, 2014, and March 31, 2014.

10. 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 24.4% for the first quarter of 2015 and 27.8% for the first quarter of 2014. 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 investments in low-income housing projects. In addition, during the first quarter of 2015, our effective tax rate was reduced by additional federal tax credit refunds filed for prior years.

Deferred Tax Asset

At March 31, 2015, from continuing operations, we had a net federal deferred tax asset of $88 million and a net state deferred tax asset of $13 million compared to a net federal deferred tax asset of $174 million and a net state deferred tax asset of $20 million at December 31, 2014, and a net federal deferred tax asset of $148 million and a net state deferred tax asset of $4 million at March 31, 2014, included in “accrued income and other assets” on the balance sheet. 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 less than $1 million at March 31, 2015, and at December 31, 2014, and $1 million at March 31, 2014, associated with certain state net operating loss carryforwards and state credit carryforwards.

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.

Deferred tax assets were reduced in the financial statements for unrecognized tax benefits by $1 million at March 31, 2015, December 31, 2014, and March 31, 2014.