This element represents the aggregate cost of investments accounted for under the equity method of accounting.

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 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 12

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ 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 210.5-02.12)

-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 323

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=16385135&loc=d3e33749-111570

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Portion of equity (net assets) in a variable interest entity (VIE) not attributable, directly or indirectly, to the parent entity. That is, this is the portion of equity in a VIE that is attributable to the noncontrolling interest (previously referred to as minority interest).

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ 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 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_VariableInterestEntityLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 5A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=28200181&loc=SL6759159-111685

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Agreement Termination Date

+ References

No definition available.

+ Details

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Namespace Prefix:	wm_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value of restricted trust funds and escrow accounts for which the company is not the sole beneficiary specifically for future settlement of landfill and environmental remediation liabilities.

+ References

No definition available.

+ Details

Name:	wm_CarryingValueOfRestrictedTrustFundsAndEscrowAccountsForWhichCompanyIsNotSoleBeneficiarySpecificallyForFutureSettlementOfLandfillAndEnvironmentalRemediationLiabilities
Namespace Prefix:	wm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Equity method investment non-cash component.

+ References

No definition available.

+ Details

Name:	wm_EquityMethodInvestmentNonCashComponent
Namespace Prefix:	wm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Variable interest entities primary beneficiary trust fair value assets.

+ References

No definition available.

+ Details

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Namespace Prefix:	wm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Variable interest entity, noncontrolling interest in consolidated net income.

+ References

No definition available.

+ Details

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Namespace Prefix:	wm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Variable interest entity third party ownership percentage.

+ References

No definition available.

+ Details

Name:	wm_VariableInterestEntityThirdPartyOwnershipPercentage
Namespace Prefix:	wm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=wm_WasteToEnergyLlcMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

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- Details

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- Details

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Data Type:	na
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Variable Interest Entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended		1 Months Ended
	Mar. 31, 2012	Dec. 31, 2014	Jan. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2000
Variable Interest Entity [Line Items]
Investment balance		228us-gaap_EquityMethodInvestments			$ 437us-gaap_EquityMethodInvestments
Carrying value of restricted trust funds and escrow accounts for which company is not the sole beneficiary specifically for future settlement of landfill and environmental remediation liabilities		113			110
Trust For Final Capping Closure Post Closure or Environmental Remediation Obligations Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net property and equipment		129			125
Investment in Recycling and Waste-to-Energy [Member]
Variable Interest Entity [Line Items]
Percentage of ownership in LLC's	50.00%
Investment in Recycling and Waste-to-Energy [Member] \| Maximum [Member]
Variable Interest Entity [Line Items]
Project agreement termination date		May 16, 2014
Investment in Refined Coal Facility [Member]
Variable Interest Entity [Line Items]
Cash payments to acquire equity method investment			48
Investment balance		32			27
Low-Income Housing Properties [Member]
Variable Interest Entity [Line Items]
Cash payments to acquire equity method investment				6
Investment balance		104			129
Consideration for investment				221
Value of notes payable included in consideration for investment				215
Equity method investments debt balance		104			128
Waste To Energy LLC [Member]
Variable Interest Entity [Line Items]
Net property and equipment					284
Noncontrolling interests					239
Expense recognized for other companies' noncontrolling interests in LLCs earnings		39			$ 43	$ 45
Waste To Energy LLC [Member] \| Waste To Energy LLC 1 [Member]
Variable Interest Entity [Line Items]
Percentage of ownership in LLC's							0.50%
Percentage of variable interest entities owned by other companies							99.50%
Waste To Energy LLC [Member] \| Waste To Energy LLC II [Member]
Variable Interest Entity [Line Items]
Percentage of ownership in LLC's							0.25%
Percentage of variable interest entities owned by other companies							99.75%