XML 73 R52.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Summary of Significant Accounting Policies - Landfill (Detail) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 USD ($) site | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Significant accounting policies |  |  |
Receivables related to income tax payments in excess of our provision for income taxes | $ 504 | $ 352 |
Environmental remediation liabilities not subject to inflation or discounting | $ 103 | $ 90 |
Landfill [Member] |  |  |
Significant accounting policies |  |  |
Required period to maintain and monitor landfill sites | 30 years |  |
Inflation rate | 2.50% | 2.50% | 2.50%
Credit adjusted, risk free discount rate applicable to long-term asset retirement obligations | 5.75% |  |
Number of landfills sites with expansion | site | 15 |  |
Number of expansion landfill sites require CFO approval inclusion of unpermitted airspace | site | 3 |  |
Number of expansion landfill sites require CFO approval inclusion of unpermitted airspace due to opposition | site | 1 |  |
Number of expansion landfill sites require CFO approval inclusion of unpermitted airspace due to time requirements | site | 2 |  |
Environmental remediation reasonably possible additional losses high estimate | $ 145 |  |
Environmental remediation liabilities | $ 251 |  |
Decrease in operating expenses |  | $ (2) | $ (2)
Risk-free discount rate applied to environmental remediation liabilities and recovery assets | 2.50% | 2.50% | 2.25%
Landfill [Member] | Minimum [Member] |  |  |
Significant accounting policies |  |  |
Permit application process period requirement | 1 year |  |
Landfill [Member] | Maximum [Member] |  |  |
Significant accounting policies |  |  |
Permit application process period requirement | 5 years |  |
Accounts Receivable Net [Member] | Concentration of Credit Risk [Member] | Maximum [Member] |  |  |
Significant accounting policies |  |  |
Concentration of risk threshold (as a percent) | 5.00% | 5.00% |

X
- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346 + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Rate applied to the undiscounted amount of environmental loss contingencies to arrive at the present value recorded as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingenciesDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(8)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(10)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_IncomeTaxReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Period of time after closure in which the entity is required to maintain and monitor a site. + References No definition available. + Details
Name: | wm_AssetRetirementObligationDuration
Namespace Prefix: | wm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage used by the reporting entity to identify a concentration of risk. + References No definition available. + Details
Name: | wm_ConcentrationOfRiskThresholdForDisclosurePercent
Namespace Prefix: | wm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Environmental Remediation Liabilities That Have Never Been Subject To Inflation Or Discounting + References No definition available. + Details
Name: | wm_EnvironmentalRemediationLiabilitiesThatHaveNeverBeenSubjectToInflationOrDiscounting
Namespace Prefix: | wm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Environmental Remediation Reasonably Possible Additional Losses High Estimate + References No definition available. + Details
Name: | wm_EnvironmentalRemediationReasonablyPossibleAdditionalLossesHighEstimate
Namespace Prefix: | wm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The increase (decrease) to operating expense due to changes in discount rates used to estimate present value of environmental remediation obligations and recovery assets. + References No definition available. + Details
Name: | wm_IncreaseDecreaseToOperatingExpensesDueToChangeInDiscountRateUsedToEstimatePresentValueOfEnvironmentalRemediationObligationsAndRecoveryAssets
Namespace Prefix: | wm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Inflation Rate + References No definition available. + Details
Name: | wm_InflationRate
Namespace Prefix: | wm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of landfill sites with expansions that require the Chief Financial Officer to approve the inclusion of the unpermitted airspace because of community or political opposition that could impede the expansion process. + References No definition available. + Details
Name: | wm_NumberOfLandfillSitesWithExpansionsThatRequireChiefFinancialOfficerToApproveInclusionOfUnpermittedAirspaceOpposition
Namespace Prefix: | wm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of landfill sites with expansions that require the Chief Financial Officer to approve the inclusion of the unpermitted airspace because the permit application process did not meet the time requirements. + References No definition available. + Details
Name: | wm_NumberOfLandfillSitesWithExpansionsThatRequireChiefFinancialOfficerToApproveInclusionOfUnpermittedAirspaceTimeRequirement
Namespace Prefix: | wm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of landfill sites with expansions that require the Chief Financial Officer to approve the inclusion of the unpermitted airspace. + References No definition available. + Details
Name: | wm_NumberOfLandfillSitesWithExpansionsThatRequireTheChiefFinancialOfficerToApproveTheInclusionOfTheUnpermittedAirspace
Namespace Prefix: | wm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Landfills Sites With Expansion + References No definition available. + Details
Name: | wm_NumberOfLandfillsSitesWithExpansion
Namespace Prefix: | wm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The permit application process period requirement. + References No definition available. + Details
Name: | wm_PermitApplicationProcessRequirement
Namespace Prefix: | wm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | wm_SignificantAccountingPoliciesLineItems
Namespace Prefix: | wm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average rate applicable to asset retirement obligations. + References No definition available. + Details
Name: | wm_WeightedAverageRateApplicableToAssetRetirementObligations
Namespace Prefix: | wm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LandfillMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |