Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Operations (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Net investment income (loss)		$ 4,091.9	$ 3,838.5	$ 4,429.6
Net realized capital gains (losses)	[1]	(72.2)	(182.1)	115.4
Total revenues		13,665.8	17,536.1	14,427.8
Expenses
Other operating costs and expenses		5,072.1	4,962.2	5,070.0
Total expenses		12,927.0	11,549.1	12,516.9
Loss before income taxes		738.8	5,987.0	1,910.9
Income taxes (benefits)		68.7	1,189.5	283.9
Net income (loss) attributable to Principal Financial Group, Inc.		623.2	4,756.9	1,580.2
Principal Financial Group, Inc. Parent Only | Legal Entities
Revenues
Net investment income (loss)		14.7	16.7	18.5
Net realized capital gains (losses)			(53.6)	(14.9)
Total revenues		14.7	(36.9)	3.6
Expenses
Other operating costs and expenses		224.0	188.8	160.9
Total expenses		224.0	188.8	160.9
Loss before income taxes		(209.3)	(225.7)	(157.3)
Income taxes (benefits)		(44.7)	(33.8)	(35.6)
Equity in the net income (loss) of subsidiaries		787.8	4,948.8	1,701.9
Net income (loss) attributable to Principal Financial Group, Inc.		$ 623.2	$ 4,756.9	$ 1,580.2

[1] Includes realized and unrealized gains (losses). See Note 4, Investments, for further details.