Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 126	$ (25)	$ 223	$ 50
Change in net unrealized gains (losses) on:
Investments with no credit impairment, net of tax provision (benefit) of $(6), $(37), $8 and $(100)	(30)	(242)	59	(580)
Investments with credit impairment, net of tax provision (benefit) of $(3), $(10), $(2) and $(19)	(10)	(44)	(5)	(83)
Change in net unrealized gains (losses) on investments	(40)	(286)	54	(663)
Change in instrument-specific credit risk on financial guaranty variable interest entities’ liabilities with recourse, net of tax	2	2	1	2
Other, net of tax	0	(8)	2	(9)
Other comprehensive income (loss)	(38)	(292)	57	(670)
Comprehensive income (loss)	88	(317)	280	(620)
Less: Comprehensive income (loss) attributable to noncontrolling interests	1	22	17	31
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ 87	$ (339)	$ 263	$ (651)