Name:	pfg_OtherActuarialBalancesLineItems
Namespace Prefix:	pfg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents collected fees or other policyholder assessments, inclusive of cost of insurance charges, administrative charges and other similar fees, for services to be provided in future periods.

No definition available.

Name:	pfg_UnearnedRevenueLiability
Namespace Prefix:	pfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount, after effect of reinsurance, of collected fees or other policyholder assessments, inclusive of cost of insurance charges, administrative charges and other similar fees, for services to be provided in future periods.

No definition available.

Name:	pfg_UnearnedRevenueLiabilityAfterReinsurance
Namespace Prefix:	pfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of deferred revenue in current period for services to be provided in future periods.

No definition available.

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

Amount of the unearned revenue liability that is reinsured to another entity.

No definition available.

Name:	pfg_UnearnedRevenueLiabilityReinsuranceImpact
Namespace Prefix:	pfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of revenue recognized that was previously included in balance of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable.

No definition available.