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Commitments And Contingencies (Narrative) (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 USD ($) site | Dec. 31, 2019 USD ($)
Commitments and Contingencies [Line Items] |  |
Sites identified which we are or may be liable for remediation costs | site | 373 |
Sites subject of actions taken by the U.S. government | site | 29 |
Sites on the Superfund National Priorities List | site | 18 |
Personal Injury [Member] |  |
Commitments and Contingencies [Line Items] |  |
Percent of liability recorded related to asserted claims | 94.00% |
Percent of liability recorded related to unasserted claims | 6.00% |
Personal Injury [Member] | Minimum [Member] |  |
Commitments and Contingencies [Line Items] |  |
Reasonably possible outcome of related claims | $ 270 |
Personal Injury [Member] | Maximum [Member] |  |
Commitments and Contingencies [Line Items] |  |
Reasonably possible outcome of related claims | 295 |
Guarantees [Member] |  |
Commitments and Contingencies [Line Items] |  |
Maximum potential amount of guarantee payments | 10 | $ 15
Recorded liability for fair value of guarantees | $ 0 | $ 0
Expiration year of final guarantee | The final guarantee expires in 2022. |

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