Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (25)	$ 102	$ 50	$ 117
Change in net unrealized gains (losses) on:
Investments with no credit impairment, net of tax provision (benefit) of $(37), $10, $(100) and $(10)	(242)	51	(580)	(68)
Investments with credit impairment, net of tax provision (benefit) of $(10), $6, $(19) and $5	(44)	24	(83)	18
Change in net unrealized gains (losses) on investments	(286)	75	(663)	(50)
Change in instrument-specific credit risk on financial guaranty variable interest entities’ liabilities with recourse, net of tax	2	(2)	2	(3)
Other, net of tax	(8)	(1)	(9)	0
Other comprehensive income (loss)	(292)	72	(670)	(53)
Comprehensive income (loss)	(317)	174	(620)	64
Less: Comprehensive income (loss) attributable to noncontrolling interests	22	4	31	8
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ (339)	$ 170	$ (651)	$ 56