Commitments and Contingencies - Summary of Future Annual Commitments Related to Minimum Quantities of Purchased Water Having Non-Cancelable Terms (Details) $ in Millions |
Dec. 31, 2019
USD ($)
|
|---|---|
| Commitments and Contingencies Disclosure [Abstract] | |
| 2020 | $ 65 |
| 2021 | 65 |
| 2022 | 65 |
| 2023 | 63 |
| 2024 | 49 |
| Thereafter | $ 605 |