Income Tax (Policies)	12 Months Ended
Income Tax (Policies)	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax, Policy [Policy Text Block]	Income Taxes We recognize deferred tax assets and liabilities based on the differences in the book and tax bases of assets and liabilities. We measure deferred tax assets and liabilities using enacted tax rates that are applicable to the period(s) that the differences are expected to reverse. We adjust deferred tax assets and liabilities for the effects of changes in tax laws and rates in the period of enactment. We recognize investment and other tax credits through our effective tax rate calculation assuming that we will be able to realize the full benefit of the credits. In 2018, we resumed investing in new LIHTC projects and elected the proportional amortization method for the associated tax credits. We amortize the cost of a LIHTC investment each reporting period in proportion to the tax credits and other tax benefits received. We recognize the resulting amortization as a component of the “provision for federal income taxes” in our consolidated statements of operations and comprehensive income. We reduce our deferred tax assets by an allowance if, based on the weight of available positive and negative evidence, it is more likely than not (a probability of greater than 50%) that we will not realize some portion, or all, of the deferred tax asset.

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.