Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of goodwill	$ 0	$ 0
Goodwill [Line Items]
Goodwill	120,000,000	120,000,000	$ 23,000,000
Amortization expense	32,000,000	50,000,000
Corporate/ Other
Goodwill [Line Items]
Impairment of technology and intangible assets	10,000,000	7,000,000
Servicing
Goodwill [Line Items]
Goodwill	80,000,000	80,000,000
Originations
Goodwill [Line Items]
Goodwill	28,000,000	28,000,000
Xome
Goodwill [Line Items]
Goodwill	$ 12,000,000	$ 12,000,000