Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 3	$ 3
Employee Stock Purchase Plan \| 2017 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation shares authorized (in shares)	800,000
Shares available for issuance (in shares)	472,677
Shares issued during period (in shares)	59,252

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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