XML 178 R162.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Employee and Agent Benefits - Fair Value of Plan Assets (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Pension benefits |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | $ 2,909.6 | $ 2,726.3 | $ 3,550.1
Defined Benefit Plan, Tax Status [Extensible Enumeration] | Qualified benefit plans | Qualified benefit plans |
Pension benefits | Pooled separate account investments | Fixed income security portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | $ 27.9 |  |
Pension benefits | Pooled separate account investments | U.S. large cap equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 290.9 | $ 282.5 |
Pension benefits | Pooled separate account investments | U.S. small/mid cap equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 49.5 | 47.3 |
Pension benefits | Pooled separate account investments | Balanced asset allocation portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 97.0 | 101.4 |
Pension benefits | Pooled separate account investments | International equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 141.8 | 143.9 |
Pension benefits | Pooled separate account investments | Real estate investment portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 204.1 | 238.4 |
Pension benefits | Single client separate account investments | U.S. government and agencies |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 124.9 | 447.0 |
Pension benefits | Single client separate account investments | States and political subdivisions |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 27.0 | 25.0 |
Pension benefits | Single client separate account investments | Corporate debt securities |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 1,394.2 | 1,336.9 |
Pension benefits | Single client separate account investments | Commercial mortgage-backed securities |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 16.1 |
Pension benefits | Single client separate account investments | Other debt obligations |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 4.1 |
Pension benefits | Single client separate account investments | Hedge funds |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 27.9 |
Pension benefits | Single client separate account investments | Pooled separate account investment |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 497.9 | 43.7 |
Pension benefits | Single client separate account investments | Other |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 54.4 | 12.1 |
Pension benefits | Amount measured at net asset value |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 27.9 |
Pension benefits | Amount measured at net asset value | Single client separate account investments | Hedge funds |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 27.9 |
Pension benefits | Fair value hierarchy Level 1 |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 124.9 | 447.0 |
Pension benefits | Fair value hierarchy Level 1 | Single client separate account investments | U.S. government and agencies |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 124.9 | 447.0 |
Pension benefits | Fair value hierarchy Level 2 |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 2,784.7 | 2,251.4 |
Pension benefits | Fair value hierarchy Level 2 | Pooled separate account investments | Fixed income security portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 27.9 |  |
Pension benefits | Fair value hierarchy Level 2 | Pooled separate account investments | U.S. large cap equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 290.9 | 282.5 |
Pension benefits | Fair value hierarchy Level 2 | Pooled separate account investments | U.S. small/mid cap equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 49.5 | 47.3 |
Pension benefits | Fair value hierarchy Level 2 | Pooled separate account investments | Balanced asset allocation portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 97.0 | 101.4 |
Pension benefits | Fair value hierarchy Level 2 | Pooled separate account investments | International equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 141.8 | 143.9 |
Pension benefits | Fair value hierarchy Level 2 | Pooled separate account investments | Real estate investment portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 204.1 | 238.4 |
Pension benefits | Fair value hierarchy Level 2 | Single client separate account investments | States and political subdivisions |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 27.0 | 25.0 |
Pension benefits | Fair value hierarchy Level 2 | Single client separate account investments | Corporate debt securities |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 1,394.2 | 1,336.9 |
Pension benefits | Fair value hierarchy Level 2 | Single client separate account investments | Commercial mortgage-backed securities |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 16.1 |
Pension benefits | Fair value hierarchy Level 2 | Single client separate account investments | Other debt obligations |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets |  | 4.1 |
Pension benefits | Fair value hierarchy Level 2 | Single client separate account investments | Pooled separate account investment |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 497.9 | 43.7 |
Pension benefits | Fair value hierarchy Level 2 | Single client separate account investments | Other |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 54.4 | 12.1 |
Other postretirement benefits |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 99.8 | 94.4 | $ 119.8
Other postretirement benefits | Cash and cash equivalents |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 1.3 | 0.6 |
Other postretirement benefits | Fixed income security portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 47.9 | 47.6 |
Other postretirement benefits | U.S. equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 36.7 | 33.6 |
Other postretirement benefits | International equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 13.9 | 12.6 |
Other postretirement benefits | Fair value hierarchy Level 1 |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 99.8 | 94.4 |
Other postretirement benefits | Fair value hierarchy Level 1 | Cash and cash equivalents |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 1.3 | 0.6 |
Other postretirement benefits | Fair value hierarchy Level 1 | Fixed income security portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 47.9 | 47.6 |
Other postretirement benefits | Fair value hierarchy Level 1 | U.S. equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | 36.7 | 33.6 |
Other postretirement benefits | Fair value hierarchy Level 1 | International equity portfolios |  |  |
Defined benefit plan, fair value of plan assets |  |  |
Fair value of plan assets | $ 13.9 | $ 12.6 |

X
- References No definition available. + Details
Name: | pfg_DefinedBenefitPlanFairValueOfPlanAssetsAbstract
Namespace Prefix: | pfg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Indicates tax status of defined benefit plan designed to provide retirement benefits. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (j) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(10) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-8 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(5) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(6) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 13: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(8) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 14: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(9) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 15: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 16: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 17: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 18: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 19: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(5) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 21: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(6) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 22: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 23: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(8) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 24: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 25: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 26: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 27: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 28: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 29: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(A) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 30: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(C) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 31: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(03) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 32: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 33: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 34: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 35: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 36: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 37: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 38: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 39: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 40: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(5) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 41: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(6) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 42: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 43: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 44: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 45: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 46: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 47: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 48: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (n) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 49: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 50: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-3 Reference 51: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-3 Reference 52: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 53: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 54: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 55: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 56: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 57: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(5) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 58: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(6) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 59: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 Reference 60: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-2 Reference 61: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(B) -SubTopic 20 -Topic 715 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanTaxStatusExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | enum2:enumerationSetItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=pfg_PooledSeparateAccountInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=pfg_DefinedBenefitPlanEquitySecuritiesUsSmallMidCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=pfg_BalancedAssetAllocationPortfoliosMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=pfg_SingleClientSeparateAccountInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_HedgeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=pfg_SingleClientSeparateAccountsInvestedInPooledSeparateAccountMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=pfg_OtherPlanAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |