Insurance Liabilities - Weighted-average interest rates (Details)	Mar. 31, 2023	Mar. 31, 2022
General Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	1.78%	1.79%
Weighted-average interest rate, current discount rate	3.64%	2.67%
Individual Retirement
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	3.65%	3.04%
Weighted-average interest rate, current discount rate	5.33%	3.72%
Group Retirement
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	5.19%	4.70%
Weighted-average interest rate, current discount rate	4.91%	3.68%
Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	4.11%	4.12%
Weighted-average interest rate, current discount rate	5.08%	3.72%
Life Insurance | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, current discount rate	3.76%	3.75%
Institutional Markets
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	3.76%	3.23%
Weighted-average interest rate, current discount rate	5.04%	3.59%
Other Operations before consolidation and eliminations
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, original discount rate	4.88%	4.80%
Weighted-average interest rate, current discount rate	5.10%	3.92%
Other Operations before consolidation and eliminations | Universal Life
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average interest rate, current discount rate	4.24%	4.20%