Debt Securities - Narrative (Details)	Sep. 30, 2024 USD ($) creditRatingCategory	Dec. 31, 2023 USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Number of credit rating categories, highest | creditRatingCategory	4
Debt securities, available-for-sale	$ 4,436,578,000	$ 4,785,719,000
Interest receivable, available-for-sale debt securities	8,364,000	9,319,000
ACL on available-for-sale debt securities	0
Debt securities, held-to-maturity	3,348,698,000	3,502,411,000
Interest receivable, held-to-maturity debt securities	19,303,000	16,990,000
ACL on held-to-maturity debt securities	0	0
Past due
Schedule of Held-to-maturity Securities [Line Items]
Debt securities, available-for-sale	0	0
Debt securities, held-to-maturity	$ 0	$ 0