Debt - Covenants (Detail)	12 Months Ended
Dec. 31, 2017
Minimum [Member]
Debt Instrument Covenant Compliance [Line Items]
Interest Coverage Ratio	2.75
Maximum [Member]
Debt Instrument Covenant Compliance [Line Items]
Debt to EBITDA ratio	3.50

The ratio of debt to EBITDA required to be maintained under the terms of the debt agreement.

No definition available.

Name:	wm_DebtInstrumentCovenantDebtToEBITDARatio
Namespace Prefix:	wm_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration