Expected Loss to be Paid (Recovered) - Net Economic Loss Development (Benefit) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Schedule of Expected Losses to be Paid [Line Items]
RMBS losses	$ (34)	$ 87	$ (20)	$ 147
RMBS | United States
Schedule of Expected Losses to be Paid [Line Items]
RMBS losses	(56)	(48)	(69)	(52)
RMBS | United States | First Lien
Schedule of Expected Losses to be Paid [Line Items]
RMBS losses	(21)	(12)	(24)	(12)
RMBS | United States | Second Lien
Schedule of Expected Losses to be Paid [Line Items]
RMBS losses	$ (35)	$ (36)	$ (45)	$ (40)