Variable Interest Entities (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Variable Interest Entity
Carrying value of debt	$ 14,063	$ 13,405
Assets	29,841	29,097
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity
Assets	112	117
Low income housing investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity
Aggregate investment balance	339	178
Carrying value of debt	310	156
Trust For Final Capping, Closure, Post-closure Or Environmental Remediation Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity
Aggregate investment balance	$ 90	$ 110