Variable Interest Entities (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Assets	$ 30,128	$ 29,097
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets	114	117
Low income housing investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate investment balance	356	178
Equity method investments debt balance	321	156
Trust For Final Capping, Closure, Post-closure Or Environmental Remediation Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate investment balance	$ 94	$ 110