Variable Interest Entities (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Variable Interest Entity
Carrying value of debt	$ 15,430	$ 14,984
Assets	31,935	31,367
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity
Assets	116	113
Low income housing investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity
Aggregate investment balance	278	321
Carrying value of debt	243	295
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	$ 94	$ 93