Future Policy Benefits - Summary of Weighted Average Interest Rates (Details)	Mar. 31, 2026	Mar. 31, 2025
Future Policy Benefits [Abstract]
Original discount rate	3.92%	3.92%
Current discount rate	5.00%	5.01%

Original weighted-average discount rate at contract issue date used to measure present value of total expected payment to policyholder in excess of present value of total expected assessment. Excludes benefit classified as market risk benefit or under provisions of Topic 815 on derivative and hedging.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(6)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480081/944-40-50-6

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant