Employee Benefit Plans (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Employee Benefit Plans. | |||
| Employer cash contributions | $ 28 | $ 25 | $ 26 |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. No definition available.
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