Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 185	$ 113
Change in net unrealized gains (losses) on:
Investments with no credit impairment, net of tax provision (benefit) of $6 and $(5)	52	(29)
Investments with credit impairment, net of tax provision (benefit) of $5 and $0	21	1
Change in net unrealized gains (losses) on investments	73	(28)
Change in instrument-specific credit risk on financial guaranty variable interest entities’ liabilities with recourse, net of tax provision (benefit)	(1)	(1)
Other, net of tax provision (benefit)	(1)	1
Other comprehensive income (loss)	71	(28)
Comprehensive income (loss)	256	85
Less: Comprehensive income (loss) attributable to noncontrolling interests	9	4
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ 247	$ 81