Segment and Related Information - Revenue mix (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment revenue
Operating revenues	$ 6,443	$ 5,609	$ 18,891	$ 16,170
Collection and Disposal [Member]
Segment revenue
Operating revenues	5,321	5,084
Collection [Member]
Segment revenue
Operating revenues	3,930	3,796	11,532	11,112
Commercial [Member]
Segment revenue
Operating revenues	1,419	1,359	4,197	4,005
Industrial [Member]
Segment revenue
Operating revenues	808	797	2,339	2,323
Residential [Member]
Segment revenue
Operating revenues	884	875	2,628	2,592
Other Collection [Member]
Segment revenue
Operating revenues	819	765	2,368	2,192
Landfill [Member]
Segment revenue
Operating revenues	995	923	2,871	2,588
Transfer [Member]
Segment revenue
Operating revenues	396	365	1,121	1,022
Recycling Processing and Sales [Member]
Segment revenue
Operating revenues	372	432
WM Renewable Energy [Member]
Segment revenue
Operating revenues	115	87
WM Healthcare Solutions [Member]
Segment revenue
Operating revenues	628		1,893
Corporate and other [Member]
Segment revenue
Operating revenues	7	6
Operating Segments [Member]
Segment revenue
Operating revenues	7,908	6,840	23,122	19,741
Operating Segments [Member] | Collection and Disposal [Member]
Segment revenue
Operating revenues	6,570	6,238
Operating Segments [Member] | Collection [Member]
Segment revenue
Operating revenues	4,478	4,286	13,120	12,519
Operating Segments [Member] | Commercial [Member]
Segment revenue
Operating revenues	1,642	1,564	4,854	4,591
Operating Segments [Member] | Industrial [Member]
Segment revenue
Operating revenues	1,042	1,003	2,995	2,915
Operating Segments [Member] | Residential [Member]
Segment revenue
Operating revenues	906	897	2,694	2,659
Operating Segments [Member] | Other Collection [Member]
Segment revenue
Operating revenues	888	822	2,577	2,354
Operating Segments [Member] | Landfill [Member]
Segment revenue
Operating revenues	1,402	1,311	4,041	3,725
Operating Segments [Member] | Transfer [Member]
Segment revenue
Operating revenues	690	641	1,963	1,819
Operating Segments [Member] | Recycling Processing and Sales [Member]
Segment revenue
Operating revenues	470	503
Operating Segments [Member] | WM Renewable Energy [Member]
Segment revenue
Operating revenues	116	88
Operating Segments [Member] | WM Healthcare Solutions [Member]
Segment revenue
Operating revenues	738		2,219
Operating Segments [Member] | Corporate and other [Member]
Segment revenue
Operating revenues	14	11
Intercompany Elimination [Member]
Segment revenue
Operating revenues	1,465	1,231	4,231	3,571
Intercompany Elimination [Member] | Collection and Disposal [Member]
Segment revenue
Operating revenues	1,249	1,154
Intercompany Elimination [Member] | Collection [Member]
Segment revenue
Operating revenues	548	490	1,588	1,407
Intercompany Elimination [Member] | Commercial [Member]
Segment revenue
Operating revenues	223	205	657	586
Intercompany Elimination [Member] | Industrial [Member]
Segment revenue
Operating revenues	234	206	656	592
Intercompany Elimination [Member] | Residential [Member]
Segment revenue
Operating revenues	22	22	66	67
Intercompany Elimination [Member] | Other Collection [Member]
Segment revenue
Operating revenues	69	57	209	162
Intercompany Elimination [Member] | Landfill [Member]
Segment revenue
Operating revenues	407	388	1,170	1,137
Intercompany Elimination [Member] | Transfer [Member]
Segment revenue
Operating revenues	294	276	842	$ 797
Intercompany Elimination [Member] | Recycling Processing and Sales [Member]
Segment revenue
Operating revenues	98	71
Intercompany Elimination [Member] | WM Renewable Energy [Member]
Segment revenue
Operating revenues	1	1
Intercompany Elimination [Member] | WM Healthcare Solutions [Member]
Segment revenue
Operating revenues	110		$ 326
Intercompany Elimination [Member] | Corporate and other [Member]
Segment revenue
Operating revenues	$ 7	$ 5