XML 109 R84.htm IDEA: XBRL DOCUMENT
v3.20.4

Employee Benefit Plans - Individually Significant (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Multiemployer Plans [Line Items] |  |  |
Company Contributions | $ 54 | $ 52 | $ 47
Multiemployer Plan, Total Individually Significant Pension Plans [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Company Contributions | 39 | 38 | 35
Automotive Industries Pension Plan [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Company Contributions | 1 | 1 | 1
Midwest Operating Engineers Pension Trust Fund [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Company Contributions | 2 | 2 | 2
Suburban Teamsters of Northern Illinois Pension Plan [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Company Contributions | 3 | 3 | 3
Western Conference of Teamsters Pension Plan [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Company Contributions | 33 | 32 | 29
Multiemployer Plan, Aggregate Individually Insignificant Pension Plans [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Company Contributions | $ 15 | $ 14 | $ 12

X
- Definition Amount of cost for employer contribution to multiemployer pension plan determined to be individually significant. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantEmployerContributionCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_MultiemployerPlansLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=wm_MultiemployerPlanTotalIndividuallySignificantPensionPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=wm_AutomotiveIndustriesPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=wm_MidwestOperatingEngineersPensionFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=wm_SuburbanTeamstersOfNorthernIllinoisPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=wm_WesternConferenceOfTeamstersPensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=wm_MultiemployerPlanAggregateIndividuallyInsignificantPensionPlansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |