XML 79 R54.htm IDEA: XBRL DOCUMENT v3.20.4

Summary of Significant Accounting Policies - Intangibles (Detail)	12 Months Ended
	Dec. 31, 2020
Customer and supplier relationships [Member] | Minimum [Member]
Significant accounting policies
Amortizable period of the intangible assets	10 years
Customer and supplier relationships [Member] | Maximum [Member]
Significant accounting policies
Amortizable period of the intangible assets	15 years
Covenants not-to-compete [Member]
Significant accounting policies
Amortizable period of the intangible assets	5 years

X

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
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

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=wm_CustomerAndSupplierRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_NoncompeteAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: