Variable Interest Entities and Asset Securitizations - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Loss on securitization of assets			$ 0
Other assets for its "investment" in the common securities recognized by the company of various trusts	$ 23,000,000		23,000,000		$ 23,000,000
Total assets of partnerships in which the company invested	197,955,479,000		197,955,479,000		155,107,160,000
Investment in partnership carrying amount	1,400,000,000		1,400,000,000		933,000,000
Unfunded commitments includes carrrying amount of its investments	505,000,000		505,000,000		361,000,000
Maximum exposure to loss of investments in real estate partnerships	1,600,000,000		1,600,000,000
Investments amortized to income tax expense	37,000,000	$ 25,000,000	94,000,000	$ 63,000,000
Federal tax credits and other federal tax benefits recognized	44,000,000	$ 27,000,000	108,000,000	$ 70,000,000
Variable Interest Entity Primary Beneficiary [Member]
Total assets of partnerships in which the company invested	$ 8,500,000,000		$ 8,500,000,000		$ 3,000,000,000.0