Insurance Liabilities - Weighted-Average Interest Rates (Details)	Mar. 31, 2024	Mar. 31, 2023
General Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	1.84%	1.78%
Weighted-average interest rate, current discount rate	3.70%	3.64%
Individual Retirement
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	3.79%	3.65%
Weighted-average interest rate, current discount rate	5.27%	5.33%
Group Retirement
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	5.13%	5.19%
Weighted-average interest rate, current discount rate	5.24%	4.91%
Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	4.12%	4.11%
Weighted-average interest rate, current discount rate	5.28%	5.08%
Life Insurance | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, current discount rate	3.92%	3.76%
Institutional Markets
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	4.25%	3.76%
Weighted-average interest rate, current discount rate	5.19%	5.04%
Other
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	4.86%	4.88%
Weighted-average interest rate, current discount rate	5.32%	5.10%
Other | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, current discount rate	4.20%	4.24%