Variable Interest Entities and Asset Securitizations - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Loss on securitization of assets	$ 0
Other assets for its "investment" in the common securities recognized by the company of various trusts	22,000,000		$ 22,000,000
Total assets of partnerships in which the company invested	215,137,000,000		208,264,000,000
Investments which met the eligibility criteria	0
Maximum exposure to loss of investments in real estate partnerships	2,200,000,000
Loans	132,782,000,000		131,939,000,000
Asset-backed notes	934,000,000		474,000,000
Senior notes	3,743,000,000		3,741,000,000
Certificates issued	15,000,000
Tax benefit	133,000,000	$ 224,000,000
Renewable Energy Investments [Member]
Reduction to income tax expense	11,000,000	8,000,000
Asset-Backed Notes [Member]
Loans	$ 526,000,000
Loans and leases average rate	5.29%
Senior notes	$ 511,000,000
Asset-backed notes weighed average estimated life	2 years
Variable Interest Entity Primary Beneficiary [Member]
Total assets of partnerships in which the company invested	$ 9,800,000,000		$ 9,800,000,000
Variable Interest Entity Primary Beneficiary [Member] | Investments In Partnerships [Member]
Reduction to income tax expense	7,000,000	6,000,000
Investments amortized to income tax expense	$ 43,000,000	$ 41,000,000