Consolidated Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Forward MSRs - fair value	$ 2,757,000,000	$ 3,496,000,000
Advances and other receivables, reserves	216,000,000	175,000,000
Purchase discount, net	127,000,000	114,000,000
Accumulated depreciation	$ 75,000,000	$ 55,000,000
Preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	1,000,000	1,000,000
Preferred stock, shares outstanding (in shares)	1,000,000	1,000,000
Preferred stock, liquidation preference	$ 10	$ 10
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares, issued (in shares)	92,000,000.0	91,100,000