Indebtedness - Summary of Unsecured Senior Notes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Aug. 01, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Unsecured senior notes, net	$ 3,151,000,000		$ 2,673,000,000
Amortization of Debt Discount (Premium)	5,000,000
Home Point Capital Inc
Debt Instrument [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Senior Note		$ 500,000,000
Debt Instrument, Unamortized Discount		$ 32,000,000
Unsecured Senior Notes
Debt Instrument [Line Items]
Unsecured senior notes principal amount	3,200,000,000		2,700,000,000
Purchase discount(1) and unamortized debt issuance costs	(49,000,000)		(27,000,000)
Unsecured senior notes, net	3,151,000,000		2,673,000,000
2026	500,000,000
2027	600,000,000
2028	850,000,000
Unsecured Senior Notes | $850 face value, 5.500% interest rate payable semi-annually, due August 2028
Debt Instrument [Line Items]
Unsecured senior notes principal amount	850,000,000		850,000,000
Face amount	$ 850,000,000
Interest rate	5.50%
Unsecured Senior Notes | $650 face value, 5.125% interest rate payable semi-annually, due December 2030
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 650,000,000		650,000,000
Face amount	$ 650,000,000
Interest rate	5.125%
Unsecured Senior Notes | $600 face value, 6.000% interest rate payable semi-annually, due January 2027
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 600,000,000		600,000,000
Face amount	$ 600,000,000
Interest rate	6.00%
Unsecured Senior Notes | $600 face value, 5.750% interest rate payable semi-annually, due November 2031
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 600,000,000		600,000,000
Face amount	$ 600,000,000
Interest rate	5.75%
Unsecured Senior Notes | $550 face value, 5.000% interest rate payable semi-annually, due January 2026(1)
Debt Instrument [Line Items]
Unsecured senior notes principal amount	$ 500,000,000		$ 0
Face amount	$ 550,000,000
Interest rate	5.00%