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Landfill and Environmental Remediation Liabilities (Tables) | 12 Months Ended
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Dec. 31, 2020
Landfill and Environmental Remediation Liabilities |
Liabilities for Landfill and Environmental Remediation Costs | Liabilities for landfill and environmental remediation costs as of December 31 are presented in the table below (in millions):
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | 2020 | ​ | 2019
​ | ​ | ​ | ​ | ​ | Environmental | ​ | ​ | ​ | ​ | ​ | ​ | ​ | Environmental | ​ | ​ | ​
​ |  | Landfill |  | Remediation |  | Total |  | Landfill |  | Remediation |  | Total
Current (in accrued liabilities) |  | $ | 138 | ​ | $ | 26 | ​ | $ | 164 | ​ | $ | 138 | ​ | $ | 27 | ​ | $ | 165
Long-term | ​ |  | 2,018 | ​ |  | 204 | ​ |  | 2,222 |  |  | 1,717 | ​ |  | 213 | ​ |  | 1,930
​ |  | $ | 2,156 | ​ | $ | 230 | ​ | $ | 2,386 | ​ | $ | 1,855 | ​ | $ | 240 | ​ | $ | 2,095
Changes to Landfill and Environmental Remediation Liabilities | The changes to landfill and environmental remediation liabilities for the year ended December 31, 2020 are reflected in the table below (in millions):
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Environmental
​ |  | Landfill |  | Remediation
December 31, 2019 | ​ | $ | 1,855 | ​ | $ | 240
Obligations incurred and capitalized | ​ |  | 83 |  |  | —
Obligations settled | ​ |  | (103) |  |  | (23)
Interest accretion | ​ |  | 103 |  |  | 2
Revisions in estimates and interest rate assumptions (a) (b) | ​ |  | (27) |  |  | 11
Acquisitions, divestitures and other adjustments (c) | ​ |  | 245 |  |  | —
December 31, 2020 | ​ | $ | 2,156 | ​ | $ | 230
(a) | The amount reported for our landfill liabilities includes a reduction of $104 million related to the change in inflation rate from 2.5% to 2.25% as of December 31, 2020, of which $26 million was an immediate reduction to amortization expense. This reduction to landfill liabilities was partially offset by (i) an increase of $69 million primarily from changes in the timing and amount of costs as well as changes in estimates of remaining airspace and (ii) an increase of $8 million due to a business decision to close one of our landfills, which resulted in the acceleration of the expected timing of capping, closure and post-closure activities. This business decision also resulted in an impairment that is discussed in Note 12.
(b) | The amount reported for our environmental remediation liabilities includes an increase of $9 million due to a decrease in the risk-free discount rate used to measure our liabilities from 1.75% at December 31, 2019 to 1.00% at December 31, 2020.
(c) | The amount reported for our landfill liabilities includes (i) $261 million related to our acquisition of Advanced Disposal offset by (ii) a reduction of $17 million for the sale of certain landfills to GFL Environmental Inc. (“GFL Environmental”) in connection with the Advanced Disposal acquisition. These items are discussed further in Note 18.

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- Definition Tabular disclosure of material liabilities for remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal or abandonment of a property as a result of unanticipated contamination of the assets. + 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.Q4) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
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