Investment Securities - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Schedule of Held-to-maturity Securities [Line Items]
Allowance for credit loss related to held-to-maturity securities	$ 0	$ 0
Investment grade percentage	98.00%	98.00%
Non-agency CMBS
Schedule of Held-to-maturity Securities [Line Items]
Allowance for credit loss related to held-to-maturity securities	$ 54	$ 44