Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 97	$ 75
Change in net unrealized gains (losses) on:
Investments with no credit impairment, net of tax provision (benefit) of $14 and $(63)	89	(338)
Investments with credit impairment, net of tax provision (benefit) of $1 and $(9)	5	(39)
Change in net unrealized gains (losses) on investments	94	(377)
Change in instrument-specific credit risk on financial guaranty variable interest entities’ liabilities with recourse, net of tax	(1)	0
Other, net of tax	2	(1)
Other comprehensive income (loss)	95	(378)
Comprehensive income (loss)	192	(303)
Less: Comprehensive income (loss) attributable to noncontrolling interests	16	9
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ 176	$ (312)