Insurance Premiums (Roll Forward Of Premiums Receivable) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Insurance Premiums [Abstract]
Premiums Receivable, Beginning balance		$ 178	$ 216
Premium Payments Received		(20)	(44)
Premiums from New Business Written		0	0
Adjustments, Changes in Expected Term of Policies		(6)	7
Adjustments, Accretion of Premiums Receivable Discount	[1]	5	5
Adjustments, Other	[2]	3	(6)
Premiums Receivable, Ending balance		$ 160	$ 178

[1] Recorded within premiums earned on MBIA’s consolidated statement of operations.

[2] The change primarily relates to the reversal of credit losses under Financial Instruments—Credit Losses, due to policy terminations.