Federal Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal Income Taxes [Abstract]
Federal statutory rate	21.00%	21.00%	35.00%
Net operating loss carryforwards	$ 1,000
Tax credit carryforward, valuation allowance	0
Unrecognized tax benefits, that, if recognized, would impact income tax expense and effective tax rate	41	$ 12
Recognized interest and penalty expense related to uncertain tax positions	0	0	$ 0
Accrued interest and penalty expense related to unrecognized tax benefits	$ 0	$ 0

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount of valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from tax credit carryforwards for which it is more likely than not that a tax benefit will not be realized.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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