Acquisitions and Divestitures - Pro Forma Consolidated Results of Operations (Detail) (Greenstar LLC [Member], RCI Environnement Inc [Member], USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Greenstar LLC [Member] | RCI Environnement Inc [Member]
Business Acquisition [Line Items]
Operating revenues	$ 3,572	$ 6,963
Net income attributable to Waste Management, Inc.	$ 245	$ 413
Basic earnings per common share	$ 0.52	$ 0.88
Diluted earnings per common share	$ 0.52	$ 0.88