Fair Value Measurements - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Unfunded commitments, equity securities measured at net asset value	$ 21		$ 21
Revaluation period	90 days
Deferred fee income	$ 3		3
Unfunded Loan Commitment
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Deferred fee income	165		$ 162
Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Transfers Out of Level 3	135	$ 428
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	(13)	(1)
Level 3 | Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Transfers Out of Level 3	128	403
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	(13)	(1)
Level 3 | Deposits
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Transfers Out of Level 3	7	25
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$ 0	$ 0