Condensed Consolidating Financial Statements - Balance Sheets (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Current assets:
Cash and cash equivalents	$ 47	$ 22	$ 32
Other current assets	2,424	2,602
Total current assets	2,471	2,624
Property and equipment, net	11,625	11,559
Other assets	7,918	7,646
Total assets	22,014	21,829
Current liabilities:
Current portion of long-term debt	828	739
Accounts payable and other current liabilities	2,477	2,523
Total current liabilities	3,305	3,262
Long-term debt, less current portion	8,968	8,752
Other liabilities	3,685	3,773
Total liabilities	15,958	15,787
Equity:
Stockholders' equity	6,054	6,019
Noncontrolling interests	2	23
Total equity	6,056	6,042
Total liabilities and equity	22,014	21,829
Eliminations [Member]
Current assets:
Investments in affiliates	(47,387)	(45,286)
Advances to affiliates	(15,969)	(15,349)
Total assets	(63,356)	(60,635)
Current liabilities:
Due to affiliates	(22,323)	(21,701)
Total liabilities	(22,323)	(21,701)
Equity:
Stockholders' equity	(47,387)	(45,286)
Advances to affiliates	6,354	6,352
Total equity	(41,033)	(38,934)
Total liabilities and equity	(63,356)	(60,635)
WM [Member] | Reportable Legal Entities [Member]
Current assets:
Other current assets	91	5
Total current assets	91	5
Investments in affiliates	23,466	22,393
Other assets	8	9
Total assets	23,565	22,407
Current liabilities:
Current portion of long-term debt	491	537
Accounts payable and other current liabilities	84	55
Total current liabilities	575	592
Long-term debt, less current portion	6,936	6,457
Due to affiliates	16,069	15,404
Other liabilities	4	8
Total liabilities	23,584	22,461
Equity:
Stockholders' equity	6,054	6,019
Advances to affiliates	(6,073)	(6,073)
Total equity	(19)	(54)
Total liabilities and equity	23,565	22,407
WM Holdings [Member] | Reportable Legal Entities [Member]
Current assets:
Other current assets	7	5
Total current assets	7	5
Investments in affiliates	23,921	22,893
Other assets	31	31
Total assets	23,959	22,929
Current liabilities:
Accounts payable and other current liabilities	9	9
Total current liabilities	9	9
Long-term debt, less current portion	304	304
Due to affiliates	181	224
Total liabilities	494	537
Equity:
Stockholders' equity	23,465	22,392
Total equity	23,465	22,392
Total liabilities and equity	23,959	22,929
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Current assets:
Cash and cash equivalents	47	22
Other current assets	2,326	2,592
Total current assets	2,373	2,614
Property and equipment, net	11,625	11,559
Advances to affiliates	15,969	15,349
Other assets	7,879	7,606
Total assets	37,846	37,128
Current liabilities:
Current portion of long-term debt	337	202
Accounts payable and other current liabilities	2,384	2,459
Total current liabilities	2,721	2,661
Long-term debt, less current portion	1,728	1,991
Due to affiliates	6,073	6,073
Other liabilities	3,681	3,765
Total liabilities	14,203	14,490
Equity:
Stockholders' equity	23,922	22,894
Advances to affiliates	(281)	(279)
Noncontrolling interests	2	23
Total equity	23,643	22,638
Total liabilities and equity	$ 37,846	$ 37,128