Long-Duration Insurance Contracts - Weighted-Average Durations of LFPB (Details)	Mar. 31, 2023	Mar. 31, 2022
Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average duration	18 years	18 years
Term Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average duration	17 years	16 years
Experience Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average duration	11 years	11 years
Limited Pay Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average duration	23 years	21 years
Supplemental health
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average duration	10 years 2 months 12 days	9 years 9 months 18 days
SPIA (life contingent)
Liability for Future Policy Benefit, by Product Segment [Line Items]
Weighted-average duration	8 years	8 years