Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 419	$ 368	$ 401
Change in net unrealized gains (losses) on:
Investments with no credit impairment, net of tax provision (benefit) of $(31), $20 and $46	(202)	163	293
Investments with credit impairment, net of tax provision (benefit) of $2, $(4) and $(14)	6	(16)	(46)
Change in net unrealized gains (losses) on investments	(196)	147	247
Change in instrument-specific credit risk on financial guaranty variable interest entities’ liabilities with recourse, net of tax	(1)	7	4
Other, net of tax	(1)	2	(2)
Other comprehensive income (loss)	(198)	156	249
Comprehensive income (loss)	221	524	650
Less: Comprehensive income (loss) attributable to noncontrolling interests	30	6	(1)
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ 191	$ 518	$ 651