Condensed Consolidating Financial Statements - Statements of Operations (Detail) - USD ($) $ 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
Condensed Income Statements, Captions [Line Items]
Operating revenues	$ 3,652	$ 3,716	$ 3,677	$ 3,440	$ 3,460	$ 3,548	$ 3,425	$ 3,176	$ 14,485	$ 13,609	$ 12,961
Costs and expenses									11,849	11,313	10,916
Income from operations	704	701	673	558	617	560	611	508	2,636	2,296	2,045
Other income (expense):
Interest expense, net									(363)	(376)	(385)
Loss on early extinguishment of debt									(6)	(4)	(555)
Other, net									(76)	(94)	(45)
Total other income (expense)									(445)	(474)	(985)
Income before income taxes									2,191	1,822	1,060
Income tax expense (benefit)									242	642	308
Consolidated net income	903	388	361	297	334	304	286	256	1,949	1,180	752
Less: Net income (loss) attributable to noncontrolling interests										(2)	(1)
Net income attributable to Waste Management, Inc.	$ 903	$ 386	$ 362	$ 298	$ 335	$ 302	$ 287	$ 258	1,949	1,182	753
Insurance premium payment									555
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues									(555)
Costs and expenses									(555)
Other income (expense):
Equity in earnings of subsidiaries, net of tax									(4,951)	(2,748)	(2,534)
Total other income (expense)									(4,951)	(2,748)	(2,534)
Income before income taxes									(4,951)	(2,748)	(2,534)
Consolidated net income									(4,951)	(2,748)	(2,534)
Net income attributable to Waste Management, Inc.									(4,951)	(2,748)	(2,534)
WM [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Costs and expenses									555
Income from operations									(555)
Other income (expense):
Interest expense, net									(299)	(303)	(298)
Loss on early extinguishment of debt									(6)	(1)	(500)
Equity in earnings of subsidiaries, net of tax									2,469	1,367	1,245
Other, net									2
Total other income (expense)									2,166	1,063	447
Income before income taxes									1,611	1,063	447
Income tax expense (benefit)									(338)	(119)	(306)
Consolidated net income									1,949	1,182	753
Net income attributable to Waste Management, Inc.									1,949	1,182	753
WM Holdings [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Costs and expenses											(1)
Income from operations											1
Other income (expense):
Interest expense, net									(20)	(20)	(22)
Loss on early extinguishment of debt											(52)
Equity in earnings of subsidiaries, net of tax									2,482	1,381	1,289
Other, net									(1)
Total other income (expense)									2,461	1,361	1,215
Income before income taxes									2,461	1,361	1,216
Income tax expense (benefit)									(8)	(8)	(29)
Consolidated net income									2,469	1,369	1,245
Net income attributable to Waste Management, Inc.									2,469	1,369	1,245
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues									15,040	13,609	12,961
Costs and expenses									11,849	11,313	10,917
Income from operations									3,191	2,296	2,044
Other income (expense):
Interest expense, net									(44)	(53)	(65)
Loss on early extinguishment of debt										(3)	(3)
Other, net									(77)	(94)	(45)
Total other income (expense)									(121)	(150)	(113)
Income before income taxes									3,070	2,146	1,931
Income tax expense (benefit)									588	769	643
Consolidated net income									2,482	1,377	1,288
Less: Net income (loss) attributable to noncontrolling interests										(2)	(1)
Net income attributable to Waste Management, Inc.									$ 2,482	$ 1,379	$ 1,289