Condensed Consolidating Financial Statements - Balance Sheets (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Current assets:
Cash and cash equivalents	$ 52	$ 22	$ 30
Other current assets	2,439	2,602
Total current assets	2,491	2,624
Property and equipment, net	11,637	11,559
Other assets	7,978	7,646
Total assets	22,106	21,829
Current liabilities:
Current portion of long-term debt	1,056	739
Accounts payable and other current liabilities	2,317	2,523
Total current liabilities	3,373	3,262
Long-term debt, less current portion	8,901	8,752
Other liabilities	3,767	3,773
Total liabilities	16,041	15,787
Equity:
Stockholders' equity	6,044	6,019
Noncontrolling interests	21	23
Total equity	6,065	6,042
Total liabilities and equity	22,106	21,829
Eliminations [Member]
Current assets:
Investments in affiliates	(46,229)	(45,286)
Advances to affiliates	(15,398)	(15,349)
Total assets	(61,627)	(60,635)
Current liabilities:
Due to affiliates	(21,748)	(21,701)
Total liabilities	(21,748)	(21,701)
Equity:
Stockholders' equity	(46,229)	(45,286)
Advances to affiliates	6,350	6,352
Total equity	(39,879)	(38,934)
Total liabilities and equity	(61,627)	(60,635)
WM [Member] | Reportable Legal Entities [Member]
Current assets:
Other current assets	139	5
Total current assets	139	5
Investments in affiliates	22,878	22,393
Other assets	5	9
Total assets	23,022	22,407
Current liabilities:
Current portion of long-term debt	544	537
Accounts payable and other current liabilities	76	55
Total current liabilities	620	592
Long-term debt, less current portion	6,954	6,457
Due to affiliates	15,472	15,404
Other liabilities	5	8
Total liabilities	23,051	22,461
Equity:
Stockholders' equity	6,044	6,019
Advances to affiliates	(6,073)	(6,073)
Total equity	(29)	(54)
Total liabilities and equity	23,022	22,407
WM Holdings [Member] | Reportable Legal Entities [Member]
Current assets:
Other current assets	5	5
Total current assets	5	5
Investments in affiliates	23,351	22,893
Other assets	31	31
Total assets	23,387	22,929
Current liabilities:
Accounts payable and other current liabilities	3	9
Total current liabilities	3	9
Long-term debt, less current portion	304	304
Due to affiliates	203	224
Total liabilities	510	537
Equity:
Stockholders' equity	22,877	22,392
Total equity	22,877	22,392
Total liabilities and equity	23,387	22,929
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Current assets:
Cash and cash equivalents	52	22
Other current assets	2,295	2,592
Total current assets	2,347	2,614
Property and equipment, net	11,637	11,559
Advances to affiliates	15,398	15,349
Other assets	7,942	7,606
Total assets	37,324	37,128
Current liabilities:
Current portion of long-term debt	512	202
Accounts payable and other current liabilities	2,238	2,459
Total current liabilities	2,750	2,661
Long-term debt, less current portion	1,643	1,991
Due to affiliates	6,073	6,073
Other liabilities	3,762	3,765
Total liabilities	14,228	14,490
Equity:
Stockholders' equity	23,352	22,894
Advances to affiliates	(277)	(279)
Noncontrolling interests	21	23
Total equity	23,096	22,638
Total liabilities and equity	$ 37,324	$ 37,128