Mortgage Servicing Rights and Related Liabilities - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Servicing Assets at Fair Value [Line Items]
Excess spread financing - fair value	$ 357		$ 386
Excess Spread Financing UPB, Fair Value Disclosure	63,113		$ 66,519
Sale of Excess Yield, UPB	20,562	$ 27,841
Sale of Excess Yield, Total Proceeds	138	226
Gain on Sale of Excess Yield	(10)	27
Forward MSRs Sold
Servicing Assets at Fair Value [Line Items]
Unpaid principal balance sold	8,583	3,305
Forward MSRs Sold, Subservicing Retained
Servicing Assets at Fair Value [Line Items]
UPB	$ 8,091	$ 3,029