Advances and Other Receivables, Net - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Jul. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Jul. 31, 2018	Sep. 30, 2019	Jun. 30, 2019	Feb. 28, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cumulative incurred losses related to advances and other receivables associated with inactive and liquidated loans		$ 13	$ 18		$ 46
Receivables discount	$ 56	56	48	$ 56	48	$ 48		$ 48
Utilization of purchase discounts		$ 0	0		0
Receivables From Prior Servicers, Forward Loan Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Account receivables			101		101			94
Pacific Union
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables discount							$ 19
WMIH Corp And Wand Merger Corporation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables discount			$ 196		196			$ 302
Utilization of purchase discounts					$ 125
Nationstar Mortgage Holdings Inc.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cumulative incurred losses related to advances and other receivables associated with inactive and liquidated loans	$ 4			$ 38