Parent Company - Condensed Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Income Statements, Captions [Line Items]
Net investment income	$ 365	$ 269	$ 269
Net realized investment gains (losses)	(14)	(56)	15
Total revenues	1,373	723	848
Other expenses	217	167	179
Total expenses	733	536	465
Income (loss) before income taxes and equity in earnings (losses) of investees	640	187	383
Equity in earnings (losses) of investees	28	(39)	94
Net income (loss) attributable to Assured Guaranty Ltd.	739	124	389
Other comprehensive income (loss)	156	(815)	(198)
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	895	(691)	191
Assured Guaranty Ltd. (Parent)
Condensed Income Statements, Captions [Line Items]
Net investment income	1	3	1
Net realized investment gains (losses)	(1)	(4)	0
Total revenues	0	(1)	1
Other expenses	45	45	35
Total expenses	45	45	35
Income (loss) before income taxes and equity in earnings (losses) of investees	(45)	(46)	(34)
Equity in earnings (losses) of investees	784	170	423
Net income (loss) attributable to Assured Guaranty Ltd.	739	124	389
Other comprehensive income (loss)	156	(815)	(198)
Comprehensive income (loss) attributable to Assured Guaranty Ltd.	$ 895	$ (691)	$ 191