Reinsurance - Components of Net Investment Income on Funds Withheld Assets (Details) - Talcott Life & Annuity Re $ in Millions	12 Months Ended
Dec. 31, 2022 USD ($)
Reinsurance
Total	$ 869.9
Investment expenses	(20.5)
Net investment income	849.4
Fixed maturities, available-for-sale
Reinsurance
Total	745.9
Fixed maturities, trading
Reinsurance
Total	2.0
Equity securities
Reinsurance
Total	0.6
Mortgage loans
Reinsurance
Total	98.4
Cash and cash equivalents
Reinsurance
Total	18.2
Other
Reinsurance
Total	$ 4.8

Income on funds withheld assets passed to coinsurer, derived from investments and on cash and cash equivalents, net of amortization of purchase discounts and premiums related to investments in debt securities. Interest income represents earnings which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Dividend income represents a distribution of earnings to shareholders by investee companies. The purchase discount or premium is amortized to income or expense, respectively, over the life (holding period) of the securities to arrive at an amount of periodic interest income or expense which results in a constant effective yield on the investments.

No definition available.

Name:	pfg_GrossInvestmentIncomeLossOnFundsWithheldAssets
Namespace Prefix:	pfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration