Quarterly Financial Data (Unaudited) - Summary (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data
Operating revenues	$ 3,652	$ 3,716	$ 3,677	$ 3,440	$ 3,460	$ 3,548	$ 3,425	$ 3,176	$ 14,485	$ 13,609	$ 12,961
Income from operations	704	701	673	558	617	560	611	508	2,636	2,296	2,045
Consolidated net income	903	388	361	297	334	304	286	256	1,949	1,180	752
Net income attributable to Waste Management, Inc.	$ 903	$ 386	$ 362	$ 298	$ 335	$ 302	$ 287	$ 258	$ 1,949	$ 1,182	$ 753
Basic earnings per common share	$ 2.08	$ 0.88	$ 0.82	$ 0.68	$ 0.76	$ 0.68	$ 0.65	$ 0.58	$ 4.44	$ 2.66	$ 1.66
Diluted earnings per common share	$ 2.06	$ 0.87	$ 0.81	$ 0.67	$ 0.75	$ 0.68	$ 0.64	$ 0.58	$ 4.41	$ 2.65	$ 1.65