Mortgage Servicing Rights and Related Liabilities - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Servicing Assets at Fair Value [Line Items]
Excess spread financing - fair value	$ 366		$ 386
Excess Spread Financing UPB, Fair Value Disclosure	64,839		$ 66,519
Sale of Excess Yield, UPB	20,562
Sale of Excess Yield, Total Proceeds	138
Gain on Sale of Excess Yield	(10)
Forward MSRs Sold
Servicing Assets at Fair Value [Line Items]
Unpaid principal balance sold	1,505	$ 3,144
Forward MSRs Sold, Subservicing Retained
Servicing Assets at Fair Value [Line Items]
UPB	$ 1,299	$ 3,003