Changes in Benefit Obligations and Plan Assets Table (Details) - Defined Benefit Pension Plan - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Net Periodic Benefit Cost
Net periodic pension cost	$ 2	$ 1
Interest cost	5	5
Actuarial loss	2	2
Expected return on plan assets	(5)	(7)
Benefit Obligations
Defined Benefit Plan, Benefit Obligation	143	128
Fair value of plan assets	100	90
Underfunded at end of year	$ 43	$ 38

Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of cost recognized for passage of time related to defined benefit plan.

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Amount of net periodic benefit cost (credit) for defined benefit plan.

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