Contracts Accounted for as Credit Derivatives - Credit Derivatives Subordination and Ratings (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Credit Derivatives
Estimated remaining weighted average life of credit derivatives (in years)	13 years 3 months 18 days	13 years 2 months 12 days
Net Par Outstanding on Credit Derivatives
Net Par Outstanding	$ 3,301	$ 4,040
Net Fair Value Asset (Liability)	(147)	(154)
Expected loss to be recovered	5	5
Public finance | United States
Net Par Outstanding on Credit Derivatives
Net Par Outstanding	1,348	1,705
Net Fair Value Asset (Liability)	(80)	(72)
Public finance | Non United States
Net Par Outstanding on Credit Derivatives
Net Par Outstanding	1,476	1,800
Net Fair Value Asset (Liability)	(42)	(48)
Structured finance | United States
Net Par Outstanding on Credit Derivatives
Net Par Outstanding	355	400
Net Fair Value Asset (Liability)	(22)	(32)
Structured finance | Non United States
Net Par Outstanding on Credit Derivatives
Net Par Outstanding	122	135
Net Fair Value Asset (Liability)	$ (3)	$ (2)