Expected Loss to be Paid (Recovered) - Net Expected Loss to be Paid (Recovered) and Net Economic Loss Development (Benefit) by Accounting Model (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	$ 199	$ 471	$ 199	$ 471	$ 466	$ 529	$ 735	$ 737
Net Economic Loss Development (Benefit)	(94)	70	(101)	101
RMBS | United States
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	142	137	142	137	$ 178	148	$ 128	$ 146
Net Economic Loss Development (Benefit)	(65)	1	(82)	(61)
RMBS | First Lien | United States
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	160		160			133
Net Economic Loss Development (Benefit)	(10)	6	1	(49)
RMBS | Second Lien | United States
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	(18)		(18)			15
Net Economic Loss Development (Benefit)	(55)	(5)	(83)	(12)
Insurance
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	150		150			471
Net Economic Loss Development (Benefit)	(82)	65	(91)	96
FG VIEs and other
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	43		43			59
Net Economic Loss Development (Benefit)	(10)	(2)	(17)	5
Credit derivatives
Schedule of Expected Losses to be Paid [Line Items]
Net Expected Loss to be Paid (Recovered)	6		6			$ (1)
Net Economic Loss Development (Benefit)	$ (2)	$ 7	$ 7	$ 0