Mortgage Servicing Rights and Related Liabilities - UPB related to owned MSRs (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024
Mortgage servicing rights
Owned Service Loans [Line Items]
UPB	$ 730,508	$ 736,071
Fair Value	11,431	11,736
Forward MSRs Sold, Subservicing Retained
Owned Service Loans [Line Items]
UPB	8,091		$ 3,029
Agency | Mortgage servicing rights
Owned Service Loans [Line Items]
UPB	701,793	710,997
Fair Value	11,101	11,397
Non-agency | Mortgage servicing rights
Owned Service Loans [Line Items]
UPB	28,715	25,074
Fair Value	$ 330	$ 339