Non-consolidated VIEs - Corporation's VI in non-consolidated VIEs and max exposure to loss (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Variable Interest Entity [Line Items]
Assets	$ 70,838,266	$ 67,637,917	$ 71,501,931
Variable Interest Entity Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	101,817	105,771
Maximum exposure to loss	101,817	105,771
Variable Interest Entity Not Primary Beneficiary | Servicing assets
Variable Interest Entity [Line Items]
Assets	95,714	99,614
Variable Interest Entity Not Primary Beneficiary | Mortgage servicing rights
Variable Interest Entity [Line Items]
Assets	95,714	99,614
Variable Interest Entity Not Primary Beneficiary | Other assets
Variable Interest Entity [Line Items]
Assets	6,103	6,157
Variable Interest Entity Not Primary Beneficiary | Servicing advances
Variable Interest Entity [Line Items]
Assets	$ 6,103	$ 6,157