Debt - Schedule of Carrying Value of Debt (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total debt	$ 1,729	$ 1,697
Convertible senior notes
Debt Instrument [Line Items]
Total convertible senior notes	1,663	1,660
Convertible senior notes \| 1.375% convertible senior notes due 2026
Debt Instrument [Line Items]
Total convertible senior notes	$ 496	495
Stated Interest Rate	1.375%
Convertible senior notes \| 2.75% convertible senior notes due 2025
Debt Instrument [Line Items]
Total convertible senior notes	$ 561	560
Stated Interest Rate	2.75%
Convertible senior notes \| 0.75% convertible senior notes due 2024
Debt Instrument [Line Items]
Total convertible senior notes	$ 606	605
Stated Interest Rate	0.75%
Credit facilities
Debt Instrument [Line Items]
Warehouse line of credit	$ 66	37
Atlas Securitized Products, L.P. \| Credit facilities
Debt Instrument [Line Items]
Repurchase agreements	19	23
JPMorgan Chase Bank, N.A. \| Credit facilities
Debt Instrument [Line Items]
Repurchase agreements	8	0
Citibank, N.A. \| Credit facilities
Debt Instrument [Line Items]
Repurchase agreements	0	3
Comerica Bank \| Line of Credit \| Credit facilities
Debt Instrument [Line Items]
Warehouse line of credit	$ 39	$ 11

Contractual interest rate for funds borrowed, under the debt agreement.

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