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Landfill and Environmental Remediation Liabilities - Changes (Detail) - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Landfill and environmental remediation liabilities |  |  |
Interest accretion | $ 75 | $ 72 |
Ending balance, environmental remediation | 238 |  |
Advanced Disposal [Member] |  |  |
Landfill and environmental remediation liabilities |  |  |
Acquisitions, divestitures and other adjustments | (17) |  |
Landfill [Member] |  |  |
Landfill and environmental remediation liabilities |  |  |
Beginning balance, landfill | 1,855 |  |
Obligations incurred and capitalized | 61 |  |
Obligations settled | (75) |  |
Interest accretion | 75 |  |
Revisions in estimates and interest rate assumptions | 30 |  |
Acquisitions, divestitures and other adjustments | (18) |  |
Ending balance, landfill | 1,928 |  |
Asset retirement obligation revision of estimate increase (decrease) related to estimated capping activities | 10 |  |
Asset retirement obligation, increase (decrease) related to landfill closure | 8 |  |
Environmental Remediation Liabilities [Member] |  |  |
Landfill and environmental remediation liabilities |  |  |
Beginning balance, environmental remediation | 240 |  |
Obligations settled | (17) |  |
Interest accretion | 1 |  |
Revisions in estimates and interest rate assumptions | 14 |  |
Ending balance, environmental remediation | 238 |  |
Increase (decrease) operating expenses due to change in discount rate | $ 12 |  |
Risk-free discount rate of the obligations | 0.75% |  | 1.75%

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- Definition Amount of expense for newly incurred environmental loss contingencies. Includes, but is not limited to, remediation expense and interest accretion. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 5.Y.Q2) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
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