Summary of Significant Accounting Policies - Landfill (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) item site	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Significant accounting policies
Number of expansion landfill sites require CFO approval inclusion of unpermitted airspace | item	2
Environmental remediation reasonably possible additional losses high estimate	$ 135
Environmental remediation liabilities	213
Environmental remediation liabilities not subject to inflation or discounting	31	$ 34
Increase (decrease) in environmental remediation liabilities	$ (6)	$ (12)
Landfill [Member]
Significant accounting policies
Inflation rate	2.25%	2.25%	2.50%
Credit adjusted, risk free discount rate applicable to long-term asset retirement obligations	4.60%
Number of landfills sites with expansion | site	15
Landfill [Member] | Minimum [Member]
Significant accounting policies
Permit application process period requirement	1 year
Landfill [Member] | Maximum [Member]
Significant accounting policies
Permit application process period requirement	5 years
Accounts Receivable Net [Member] | Concentration of Credit Risk [Member] | Maximum [Member]
Significant accounting policies
Concentration of risk threshold (as a percent)	5.00%	5.00%
Environmental Remediation Liabilities [Member]
Significant accounting policies
Environmental remediation liabilities	$ 213	$ 230
Increase (decrease) in operating expenses	$ (4)	$ 8	$ 9
Risk-free discount rate applied to environmental remediation liabilities and recovery assets	1.50%	1.00%	1.75%