Business Combinations and Asset Acquisitions (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Jul. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Aug. 01, 2023
Business Combination, Description [Abstract]
Asset Acquisition, Consideration Transferred			$ 34
Bargain purchase gain				$ 96	$ 0
Business Combination, Bargain Purchase, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]				Other income, net
Home Point Capital Inc [Member]
Business Combination, Description [Abstract]
Business Combination, Consideration Transferred		$ 658
Acquisition costs		5		$ 5
Business Combination, Consideration Transferred for MSRs		335
Business Combination, Consideration Transferred for Tender Offer		323
Price per share (in dollars per share)						$ 2.33
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Mortgage Servicing Rights						$ 1,200
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Senior Note						$ 500
Business Combination, Bargain Purchase, Gain Recognized, Description				The Company believes it was able to negotiate a bargain purchase price due to seller’s operational challenges from significant market volatility, as well as the seller’s desire to exit the business in an expedited manner.
Business Combination, Bargain Purchase, Gain Recognized, Description				The Company believes it was able to negotiate a bargain purchase price due to seller’s operational challenges from significant market volatility, as well as the seller’s desire to exit the business in an expedited manner.
Home Point Capital Inc [Member] | Corporate and other
Business Combination, Description [Abstract]
Bargain purchase gain		96		$ 96
Roosevelt
Business Combination, Description [Abstract]
Business Combination, Consideration Transferred	$ 28
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 4
Goodwill acquired		21
Acquisition costs		8		$ 8
Roosevelt | Servicing
Business Combination, Description [Abstract]
Goodwill acquired		5
Roosevelt | Corporate and other
Business Combination, Description [Abstract]
Goodwill acquired		$ 16