Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 137	$ 419	$ 368
Change in net unrealized gains (losses) on:
Investments with no credit impairment, net of tax provision (benefit) of $(121), $(31) and $20	(718)	(202)	163
Investments with credit impairment, net of tax provision (benefit) of $(20), $2 and $(4)	(86)	6	(16)
Change in net unrealized gains (losses) on investments	(804)	(196)	147
Change in instrument-specific credit risk on financial guaranty variable interest entities’ liabilities with recourse, net of tax	(2)	(1)	7
Other, net of tax	(9)	(1)	2
Other comprehensive income (loss)	(815)	(198)	156
Comprehensive income (loss)	(678)	221	524
Less: Comprehensive income (loss) attributable to noncontrolling interests	13	30	6
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ (691)	$ 191	$ 518