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Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions | 1 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2021 | Dec. 31, 2020 | Jul. 31, 2000
Debt Instrument [Line Items] |  |  |
Unamortized debt issuance cost | $ 27 | $ 28 |
RS Cogen |  |  |
Debt Instrument [Line Items] |  |  |
Noncontrolling Interest, Ownership Percentage by Parent | 50.00% |  |
Senior Notes | 8.73% Senior Notes Due 2022 |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate (percent) | 8.73% |  |
Senior Notes | Term Loan Due Twenty Twenty Six |  |  |
Debt Instrument [Line Items] |  |  |
Maximum borrowing capacity | $ 23 |  |
Stated interest rate (percent) | 0.20% |  |
Debt instrument term | 5 years |  |
Senior Notes | Term Loan Due Twenty Twenty Six | Taiwan Chlorine Industries, Ltd. |  |  |
Debt Instrument [Line Items] |  |  |
Noncontrolling Interest, Ownership Percentage by Parent | 60.00% |  |
Line of Credit | 8.73% Senior Notes Due 2022 |  |  |
Debt Instrument [Line Items] |  |  |
Maximum borrowing capacity |  |  | $ 75
Stated interest rate (percent) | 8.73% |  |
Line of Credit | 8.73% Senior Notes Due 2022 | RS Cogen |  |  |
Debt Instrument [Line Items] |  |  |
Noncontrolling Interest, Ownership Percentage by Parent | 50.00% |  |

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