Separate Account Balances - Principal Asset Management - Principal International (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Changes in separate account liabilities
Balance at beginning of period	$ 155,375.1
Balance at end of period	162,000.8	$ 155,375.1
Principal Asset Management | Principal International
Changes in separate account liabilities
Balance at beginning of period	34,231.7
Balance at end of period	36,314.6	34,231.7
Principal Asset Management | Principal International | Pension | Latin America
Changes in separate account liabilities
Balance at beginning of period	33,316.7	33,030.6
Premiums and deposits	812.7	3,620.4
Policy charges	(4.7)	(18.2)
Surrenders, withdrawals and benefit payments	(988.9)	(3,984.6)
Investment performance	(303.8)	498.8
Other	(28.7)	(0.8)
Foreign currency translation adjustment	2,582.5	170.5
Balance at end of period	35,385.8	33,316.7
Cash surrender value	35,385.8	33,316.7
Principal Asset Management | Principal International | Guaranteed pension | Asia
Changes in separate account liabilities
Balance at beginning of period	915.0	971.3
Premiums and deposits	66.1	276.2
Policy charges	(4.7)	(19.8)
Surrenders, withdrawals and benefit payments	(66.7)	(247.0)
Investment performance	24.5	(64.0)
Other	(0.1)	(0.4)
Foreign currency translation adjustment	(5.3)	(1.3)
Balance at end of period	928.8	915.0
Cash surrender value	$ 928.8	$ 915.0