Condensed Consolidating Financial Statements - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Operating activities	$ 1,534	$ 1,494
Investing activities	(677)	(1,186)
Financing activities	(857)	(309)
Effect of exchange rate changes on cash and cash equivalents		1
Intercompany activity	0	0
Increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	32	39
Cash and cash equivalents at end of period	32	39
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Intercompany activity	0	0
Increase (decrease) in cash and cash equivalents	0	0
WM [Member] \| Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Intercompany activity	0	0
Increase (decrease) in cash and cash equivalents	0	0
WM Holdings [Member] \| Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Intercompany activity	0	0
Increase (decrease) in cash and cash equivalents	0	0
Non-Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Operating activities	1,534	1,494
Investing activities	(677)	(1,186)
Financing activities	(857)	(309)
Effect of exchange rate changes on cash and cash equivalents		1
Intercompany activity	0	0
Increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	32	39
Cash and cash equivalents at end of period	$ 32	$ 39

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6676-107765

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3044-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
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Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes.

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Amount of increase (decrease) from the effect of exchange rate changes on cash and cash equivalent balances held in foreign currencies.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 230
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Amount of cash inflow (outflow) of financing activities, excluding discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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-Publisher FASB
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Amount of cash inflow (outflow) of investing activities, excluding discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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Amount of cash inflow (outflow) from operating activities, excluding discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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Intercompany activity.

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