Separate Account Balances - Separate Account Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Separate Account Balances
Separate account liabilities	$ 162,000.8	$ 155,375.1
Other balances
Separate Account Balances
Separate account liabilities	245.9	233.3
Retirement and Income Solutions
Separate Account Balances
Separate account liabilities	120,186.1	115,899.1
Retirement and Income Solutions | Group retirement contracts
Separate Account Balances
Separate account liabilities	111,275.8	107,240.1	$ 131,188.6
Retirement and Income Solutions | Individual variable annuities
Separate Account Balances
Separate account liabilities	8,910.3	8,659.0	11,000.0
Principal Asset Management | Principal International
Separate Account Balances
Separate account liabilities	36,314.6	34,231.7
Principal Asset Management | Principal International | Pension | Latin America
Separate Account Balances
Separate account liabilities	35,385.8	33,316.7	33,030.6
Principal Asset Management | Principal International | Guaranteed pension | Asia
Separate Account Balances
Separate account liabilities	928.8	915.0	971.3
Benefits and Protection | Life Insurance | Universal life
Separate Account Balances
Separate account liabilities	$ 5,254.2	$ 5,011.0	$ 5,886.1