Segment Information (Details)	6 Months Ended
Jun. 30, 2026
Segment Information
Number of reportable segments disclosed by definition	true

Indicates the number of reportable segments disclosed by definition.

No definition available.

Name:	pfg_NumberOfReportableSegmentsDisclosedByDefinitionFlag
Namespace Prefix:	pfg_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration