Mortgage Servicing Rights and Related Liabilities - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Servicing Asset at Amortized Cost [Line Items]
Excess spread financing - fair value	$ 491	$ 509
Forward MSRs Sold
Servicing Asset at Amortized Cost [Line Items]
UPB	1,256		$ 361
Forward MSRs Sold, Subservicing Retained
Servicing Asset at Amortized Cost [Line Items]
UPB	271		$ 342
Excess spread financing
Servicing Asset at Amortized Cost [Line Items]
UPB	$ 81,041	$ 83,706