Reconciliation of income tax computed at US Federal tax rates (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax [Abstract]
Statutory Income Tax	21.00%	21.00%	21.00%
Policyholder Reserves	(0.60%)	(1.70%)	2.00%
Other Items, Net	1.30%	0.30%	(0.80%)
Effective Tax	21.70%	19.60%	22.20%