Income Taxes - Deferred Tax Assets (Liabilities) (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Losses on loans and other assets	$ 686	$ 641	$ 396
Operating lease liabilities	182	183	110
Postretirement and other employee benefits	47		32
Incentive and other compensation plans	30	34	25
Unrealized losses	64	115
Interest on loans	42	54
Losses on cash flow hedges	52	87
Stock-based compensation	54	51	33
Other	153	81	52
Gross deferred tax assets	1,310	1,246	648
Right-of-use assets and other leasing transactions	(336)	(367)	(249)
Unrealized gains			(27)
Retirement benefits	(198)	(88)	(46)
Capitalized servicing rights	(38)	(51)	(53)
Postretirement and other employee benefits		(29)
Depreciation and amortization	(157)	(155)	(93)
Interest on loans			(7)
Gains on cash flow hedges			(23)
Other	(59)	(69)	(88)
Gross deferred tax liabilities	(788)	(759)	(586)
Net deferred tax asset	$ 522	$ 487	$ 62