Fair Value Measurements - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Weighted-average discount rates for fair value estimations	37.00%
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rates for fair value estimations	10.00%
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rates for fair value estimations	90.00%
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves	$ 35,000,000	$ 175,000,000
Level 3 | Measurement Input, Commitment Expiration
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Held-for-sale measurement input (as a percent)	0.24		0.06
Level 3 | Residential Mortgage Loans
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Capitalized servicing rights, valuation allowance	$ 0	0	$ 0
Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	524,000,000	1,000,000,000.0	847,000,000
Nonrecurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	128,000,000	312,000,000	187,000,000
Nonrecurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	$ 396,000,000	$ 707,000,000	$ 660,000,000