Segment Information - Expenses from exited business (Details) - Reconciling items - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Expenses from exited business included:
Strategic review costs and impacts			$ (40.4)
Amortization of reinsurance loss	$ 592.9	$ 74.6	69.3
Other impacts of reinsured business	(163.0)	127.7	125.8
Total expenses from exited business	$ 429.9	$ 202.3	$ 154.7

Amount of amortization expense (reversal of expense) for any reinsurance gains (losses) relating to exited business during the reporting period.

No definition available.

Name:	pfg_AmortizationExpensesOfReinsuranceGainsLossesExitedBusiness
Namespace Prefix:	pfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration