Non-consolidated VIEs - Corporation's VI in non-consolidated VIEs and max exposure to loss (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Variable Interest Entity [Line Items]
Assets	$ 70,936,939	$ 70,758,155	$ 67,675,759
Variable Interest Entity Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	97,247	99,290
Maximum exposure to loss	97,247	99,290
Variable Interest Entity Not Primary Beneficiary | Servicing assets
Variable Interest Entity [Line Items]
Assets	90,254	92,999
Variable Interest Entity Not Primary Beneficiary | Mortgage servicing rights
Variable Interest Entity [Line Items]
Assets	90,254	92,999
Variable Interest Entity Not Primary Beneficiary | Other assets
Variable Interest Entity [Line Items]
Assets	6,993	6,291
Variable Interest Entity Not Primary Beneficiary | Servicing advances
Variable Interest Entity [Line Items]
Assets	$ 6,993	$ 6,291