Segment and Related Information - Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Segment Reporting
Total assets	$ 45,608	$ 44,567
Operating Segments [Member] | Collection and Disposal [Member]
Segment Reporting
Total assets	28,821	27,893
Operating Segments [Member] | East Tier [Member]
Segment Reporting
Total assets	15,964	15,328
Operating Segments [Member] | West Tier [Member]
Segment Reporting
Total assets	12,049	11,786
Operating Segments [Member] | Other Ancillary [Member]
Segment Reporting
Total assets	808	779
Operating Segments [Member] | Recycling Processing and Sales [Member]
Segment Reporting
Total assets	2,710	2,686
Operating Segments [Member] | WM Renewable Energy [Member]
Segment Reporting
Total assets	1,879	1,544
Operating Segments [Member] | WM Healthcare Solutions [Member]
Segment Reporting
Total assets	9,098	9,406
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting
Total assets	4,019	3,785
Intercompany Elimination [Member]
Segment Reporting
Total assets	$ (919)	$ (747)