Servicing Revenue - Schedule of Product (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2026	Dec. 31, 2025
Concentration Risk [Line Items]
UPB	$ 61,287	$ 47,846
Annualized Effective Service Fee Rate	0.14%	0.14%
Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	100.00%	100.00%
Fannie Mae
Concentration Risk [Line Items]
UPB	$ 7,955	$ 7,860
Annualized Effective Service Fee Rate	0.41%	0.42%
Fannie Mae \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	13.00%	16.00%
Ginnie Mae
Concentration Risk [Line Items]
UPB	$ 5,495	$ 5,125
Annualized Effective Service Fee Rate	0.31%	0.35%
Ginnie Mae \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	9.00%	11.00%
Freddie Mac
Concentration Risk [Line Items]
UPB	$ 9,342	$ 8,649
Annualized Effective Service Fee Rate	0.14%	0.15%
Freddie Mac \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	15.00%	18.00%
Bridge
Concentration Risk [Line Items]
UPB	$ 361	$ 836
Annualized Effective Service Fee Rate	0.13%	0.16%
Bridge \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	1.00%	2.00%
Affordable
Concentration Risk [Line Items]
UPB	$ 532	$ 425
Annualized Effective Service Fee Rate	0.13%	0.26%
Affordable \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	1.00%	1.00%
Benefit Street Partners
Concentration Risk [Line Items]
UPB	$ 11,632	$ 130
Annualized Effective Service Fee Rate	0.13%	0.06%
Servicing asset at fair value, amount	$ 4,400
Benefit Street Partners \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	19.00%	0.00%
Private Label
Concentration Risk [Line Items]
UPB	$ 25,970	$ 24,821
Annualized Effective Service Fee Rate	0.04%	0.04%
Private Label \| Revenue, Product and Service Benchmark \| Product Concentration Risk
Concentration Risk [Line Items]
Percentage	42.00%	52.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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