Segment and Related Information - Revenue mix (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment revenue
Operating revenues	$ 6,430	$ 5,402	$ 12,448	$ 10,561
Collection and Disposal [Member]
Segment revenue
Operating revenues	5,281	4,922
Collection [Member]
Segment revenue
Operating revenues	3,856	3,701	7,602	7,316
Commercial [Member]
Segment revenue
Operating revenues	1,398	1,330	2,778	2,646
Industrial [Member]
Segment revenue
Operating revenues	790	779	1,531	1,526
Residential [Member]
Segment revenue
Operating revenues	872	863	1,744	1,717
Other Collection [Member]
Segment revenue
Operating revenues	796	729	1,549	1,427
Landfill [Member]
Segment revenue
Operating revenues	1,036	873	1,876	1,665
Transfer [Member]
Segment revenue
Operating revenues	389	348	725	657
Recycling Processing and Sales [Member]
Segment revenue
Operating revenues	381	405
WM Renewable Energy [Member]
Segment revenue
Operating revenues	115	69
WM Healthcare Solutions [Member]
Segment revenue
Operating revenues	646		1,265
Corporate and other [Member]
Segment revenue
Operating revenues	7	6
Operating Segments [Member]
Segment revenue
Operating revenues	7,775	6,610	15,007	12,901
Operating Segments [Member] | Collection and Disposal [Member]
Segment revenue
Operating revenues	6,516	6,051
Operating Segments [Member] | Collection [Member]
Segment revenue
Operating revenues	4,389	4,171	8,642	8,233
Operating Segments [Member] | Commercial [Member]
Segment revenue
Operating revenues	1,618	1,526	3,212	3,027
Operating Segments [Member] | Industrial [Member]
Segment revenue
Operating revenues	1,013	978	1,953	1,912
Operating Segments [Member] | Residential [Member]
Segment revenue
Operating revenues	894	886	1,788	1,762
Operating Segments [Member] | Other Collection [Member]
Segment revenue
Operating revenues	864	781	1,689	1,532
Operating Segments [Member] | Landfill [Member]
Segment revenue
Operating revenues	1,446	1,262	2,639	2,414
Operating Segments [Member] | Transfer [Member]
Segment revenue
Operating revenues	681	618	1,273	1,178
Operating Segments [Member] | Recycling Processing and Sales [Member]
Segment revenue
Operating revenues	482	475
Operating Segments [Member] | WM Renewable Energy [Member]
Segment revenue
Operating revenues	115	70
Operating Segments [Member] | WM Healthcare Solutions [Member]
Segment revenue
Operating revenues	647		1,274
Operating Segments [Member] | Corporate and other [Member]
Segment revenue
Operating revenues	15	14
Intercompany Elimination [Member]
Segment revenue
Operating revenues	1,345	1,208	2,559	2,340
Intercompany Elimination [Member] | Collection and Disposal [Member]
Segment revenue
Operating revenues	1,235	1,129
Intercompany Elimination [Member] | Collection [Member]
Segment revenue
Operating revenues	533	470	1,040	917
Intercompany Elimination [Member] | Commercial [Member]
Segment revenue
Operating revenues	220	196	434	381
Intercompany Elimination [Member] | Industrial [Member]
Segment revenue
Operating revenues	223	199	422	386
Intercompany Elimination [Member] | Residential [Member]
Segment revenue
Operating revenues	22	23	44	45
Intercompany Elimination [Member] | Other Collection [Member]
Segment revenue
Operating revenues	68	52	140	105
Intercompany Elimination [Member] | Landfill [Member]
Segment revenue
Operating revenues	410	389	763	749
Intercompany Elimination [Member] | Transfer [Member]
Segment revenue
Operating revenues	292	270	548	$ 521
Intercompany Elimination [Member] | Recycling Processing and Sales [Member]
Segment revenue
Operating revenues	101	70
Intercompany Elimination [Member] | WM Renewable Energy [Member]
Segment revenue
Operating revenues		1
Intercompany Elimination [Member] | WM Healthcare Solutions [Member]
Segment revenue
Operating revenues	1		$ 9
Intercompany Elimination [Member] | Corporate and other [Member]
Segment revenue
Operating revenues	$ 8	$ 8