Variable Interest Entities (Detail) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Variable Interest Entity
Carrying value of debt	$ 15,370	$ 14,984
Assets	31,290	31,367
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity
Assets	118	113
Low income housing investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity
Aggregate investment balance	309	321
Carrying value of debt	278	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	$ 95	$ 93