Market Risk Benefits - Asset and Liability Position and Reconciliation (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Market Risk Benefits
Market risk benefit asset	$ 107.3	$ 109.2
Market risk benefit liability	194.4	207.4
Net asset (liability)	(87.1)	(98.2)
Retirement and Income Solutions \| Individual variable annuities
Market Risk Benefits
Market risk benefit asset	107.3	109.2
Market risk benefit liability	170.4	181.4
Net asset (liability)	(63.1)	(72.2)	$ (494.7)	$ (591.3)
Principal Asset Management \| Principal International \| Guaranteed pension \| Asia
Market Risk Benefits
Market risk benefit liability	24.0	26.0
Net asset (liability)	$ (24.0)	$ (26.0)	$ (35.1)	$ (53.3)

Amount, before effect of reinsurance and after accumulated increase (decrease) in instrument-specific credit risk, of contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 65
-Paragraph 2
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
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-Topic 944
-SubTopic 40
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Amount of asset position for contract or contract feature in long-duration contract issued by insurance entity that both protects contract holder from other-than-nominal capital market risk and exposes insurance entity to other-than-nominal capital market risk.

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-Publisher FASB
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-URI https://asc.fasb.org/extlink&oid=126561865&loc=SL117819547-158441

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