Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investments	$ 6
Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value option elected aggregate carrying amount, asset	2	$ 5
Residential Loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Acquisitions	53	2,120
Business purpose loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value option elected aggregate carrying amount, asset	442	920
HEIs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Acquisitions		40
MSRs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Acquisitions		$ 6
Shared home appreciation options
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Acquisitions	$ 17

Fair Value, Option, Assets, Aggregate Carrying Amount During Period

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- Definition

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.

+ References

No definition available.

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- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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- Definition

Sum of the carrying amounts as of the balance sheet date of all investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(h))
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