Insurance Premiums (Roll Forward Of Premiums Receivable) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022
Insurance Premiums [Abstract]
Premiums Receivable, Beginning balance		$ 160		$ 178
Premium Payments Received		(18)		(20)
Premiums from New Business Written		0		0
Adjustments, Changes in Expected Term of Policies		0		(6)
Adjustments, Accretion of Premiums Receivable Discount		4	[1]	5	[2]
Adjustments, Other	[3]			3
Premiums Receivable, Ending balance		$ 146		$ 160

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

[2] Recorded within premiums earned on MBIA's consolidated statement of operations.

[3] The change primarily relates to the reversal of credit losses due to policy terminations.