Mortgage Servicing Rights and Related Liabilities - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Servicing Assets at Fair Value [Line Items]
Excess spread financing - fair value	$ 403		$ 437
Excess Spread Financing UPB, Fair Value Disclosure	68,594		$ 74,219
Sale of Excess Yield, UPB	27,841	$ 41,958
Sale of Excess Yield, Total Proceeds	226	294
Gain on Sale of Excess Yield	27	33
Forward MSRs Sold
Servicing Assets at Fair Value [Line Items]
Unpaid principal balance sold	7,716	23,789
Forward MSRs Sold, Subservicing Retained
Servicing Assets at Fair Value [Line Items]
UPB	$ 7,319	$ 22,640