Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets
Fixed maturities, available-for-sale	$ 65,673.1	$ 62,889.9
Fixed maturities, trading	836.2	760.7
Other investments	7,035.6	6,122.0
Cash and cash equivalents	4,707.7	4,848.0
Deferred income taxes	241.1	306.9
Total assets	305,046.7	290,867.0
Liabilities
Long-term debt	3,930.9	3,997.0
Income taxes currently payable	11.9	19.2
Total liabilities	293,836.1	280,587.2
Stockholders' equity
Common stock, par value $0.01 per share; 2,500,000,000 shares authorized; 492,279,405 and 489,809,564 shares issued as of 2023 and 2022; 236,438,294 and 243,549,782 shares outstanding as of 2023 and 2022	4.9	4.9
Additional paid-in capital	10,908.6	10,740.4
Retained earnings	16,683.5	16,697.3
Accumulated other comprehensive income (loss)	(5,345.3)	(6,879.0)
Treasury stock, at cost; 255,841,111 and 246,259,782 shares as of 2023 and 2022	(11,335.7)	(10,586.9)
Total stockholders' equity attributable to Principal Financial Group, Inc.	10,916.0	9,976.7
Total liabilities and stockholders' equity	305,046.7	290,867.0
Principal Financial Group, Inc. Parent Only | Legal Entities
Assets
Fixed maturities, available-for-sale	15.6	17.1
Other investments	11.5	12.0
Cash and cash equivalents	270.7	492.5
Income taxes currently receivable	11.9
Deferred income taxes	292.7	297.1
Other assets	17.4	12.6
Investment in unconsolidated entities	14,595.7	13,423.7
Total assets	15,230.5	14,269.6
Liabilities
Long-term debt	3,927.9	3,929.2
Accrued investment payable	30.6	24.7
Income taxes currently payable		2.4
Pension liability	343.6	332.7
Other liabilities	12.4	3.9
Total liabilities	4,314.5	4,292.9
Stockholders' equity
Common stock, par value $0.01 per share; 2,500,000,000 shares authorized; 492,279,405 and 489,809,564 shares issued as of 2023 and 2022; 236,438,294 and 243,549,782 shares outstanding as of 2023 and 2022	4.9	4.9
Additional paid-in capital	10,908.6	10,740.4
Retained earnings	16,683.5	16,697.3
Accumulated other comprehensive income (loss)	(5,345.3)	(6,879.0)
Treasury stock, at cost; 255,841,111 and 246,259,782 shares as of 2023 and 2022	(11,335.7)	(10,586.9)
Total stockholders' equity attributable to Principal Financial Group, Inc.	10,916.0	9,976.7
Total liabilities and stockholders' equity	15,230.5	14,269.6
Principal Financial Group, Inc. Parent Only | Legal Entities | Subsidiaries
Assets
Amounts receivable from subsidiaries	$ 15.0	$ 14.6