Principal Financial (PFG) 10-K 12 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Jan. 29, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-16725
Entity Registrant Name	PRINCIPAL FINANCIAL GROUP, INC
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	711 High Street
Entity Address, City or Town	Des Moines
Entity Address, State or Province	IA
Entity Address, Postal Zip Code	50392
Entity Tax Identification Number	42-1520346
City Area Code	515
Local Phone Number	247-5111
Title of 12(b) Security	Common Stock, par value $0.01
Trading Symbol	PFG
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		272,613,683
Entity Public Float			$ 11.4
Entity Central Index Key	0001126328
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Statements of Fina

Consolidated Statements of Financial Position - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Fixed maturities, available-for-sale (2019 includes $99.4 million related to consolidated variable interest entities)	$ 78,710.3	$ 70,106.2
Fixed maturities, trading	532.1	675.9
Equity securities (2020 and 2019 include $902.5 million and $810.9 million related to consolidated variable interest entities)	2,013.4	1,879.4
Mortgage loans (2020 includes $319.0 million related to consolidated variable interest entities)	17,343	16,486.9
Real estate (2020 and 2019 include $476.8 million and $457.6 million related to consolidated variable interest entities)	1,797.3	1,714.8
Policy loans	784	798
Other investments (2020 and 2019 include $348.5 million and $263.7 million related to consolidated variable interest entities and $28.5 million and $22.8 million measured at fair value under the fair value option)	5,126.8	4,690.2
Total investments	106,306.9	96,351.4
Cash and cash equivalents	2,849.8	2,515.9
Accrued investment income	710.6	686.6
Premiums due and other receivables	1,723.8	1,740.3
Deferred acquisition costs	3,409.7	3,521.3
Property and equipment	1,019	967.7
Goodwill	1,711	1,693.8
Other intangibles	1,723	1,786.7
Separate account assets (2020 and 2019 include $41,138.9 million and $39,130.3 million related to consolidated variable interest entities)	175,951.4	165,468
Other assets	1,222.5	1,356.1
Total assets	296,627.7	276,087.8
Liabilities
Contractholder funds (2020 and 2019 include $388.6 million and $394.6 million related to consolidated variable interest entities)	43,237.7	41,367.5
Future policy benefits and claims	45,207.2	40,838.2
Other policyholder funds	1,059.4	959.4
Short-term debt	84.7	93.4
Long-term debt (2019 includes $64.2 million related to consolidated variable interest entities)	4,279.2	3,734.1
Income taxes currently payable	22.3	16.2
Deferred income taxes	2,330.8	1,796.6
Separate account liabilities (2020 and 2019 include $41,138.9 million and $39,130.3 million related to consolidated variable interest entities)	175,951.4	165,468
Other liabilities (2020 and 2019 include $24.5 million and $124.4 million related to consolidated variable interest entities)	7,582.1	6,863.7
Total liabilities	279,754.8	261,137.1
Redeemable noncontrolling interest (2020 and 2019 include $226.8 million and $215.4 million related to consolidated variable interest entities)	255.6	264.9
Stockholders' equity
Common stock, par value $0.01 per share; 2,500 million shares authorized; 481.9 million and 479.3 million shares issued as of 2020 and 2019; 273.3 million and 276.6 million shares outstanding as of 2020 and 2019	4.8	4.8
Additional paid-in capital	10,321.6	10,182.6
Retained earnings (accumulated deficit)	11,838	11,074.3
Accumulated other comprehensive income (loss)	2,383.1	1,037.9
Treasury stock, at cost (208.6 million and 202.7 million shares as of 2020 and 2019)	(7,988.6)	(7,681.6)
Total stockholders' equity attributable to Principal Financial Group, Inc.	16,558.9	14,618
Noncontrolling interest	58.4	67.8
Total stockholders' equity	16,617.3	14,685.8
Total liabilities and stockholders' equity	$ 296,627.7	$ 276,087.8

Consolidated Statements of Fi_2

Consolidated Statements of Financial Position (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fixed maturities, available-for-sale	$ 78,710.3	$ 70,106.2
Equity securities	2,013.4	1,879.4
Mortgage loans	17,343	16,486.9
Real estate	1,797.3	1,714.8
Other investments	5,126.8	4,690.2
Other investments measured at fair value under fair value option	28.5	22.8
Separate account assets	175,951.4	165,468
Contractholder funds	43,237.7	41,367.5
Long-term debt	4,279.2	3,734.1
Separate account liabilities	175,951.4	165,468
Other liabilities	7,582.1	6,863.7
Redeemable noncontrolling interest	$ 255.6	$ 264.9
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	2,500	2,500
Common stock, issued (in shares)	481.9	479.3
Common stock, outstanding (in shares)	273.3	276.6
Treasury stock (in shares)	208.6	202.7
Aggregate consolidated variable interest entities
Fixed maturities, available-for-sale		$ 99.4
Equity securities	$ 902.5	810.9
Mortgage loans	319
Real estate	476.8	457.6
Other investments	348.5	263.7
Separate account assets	41,138.9	39,130.3
Contractholder funds	388.6	394.6
Long-term debt		64.2
Separate account liabilities	41,138.9	39,130.3
Other liabilities	24.5	124.4
Redeemable noncontrolling interest	$ 226.8	$ 215.4

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Premiums and other considerations									$ 6,037.4	$ 7,866.6	$ 6,409.6
Fees and other revenues									4,511.1	4,409.9	4,273.8
Net investment income (loss)									3,890.6	3,998.4	3,629.2
Net realized capital gains (losses)									302.6	(52.8)	(75.4)
Total revenues	$ 3,765.1	$ 3,310.7	$ 3,114.6	$ 4,551.3	$ 4,047.2	$ 4,458.4	$ 3,972.6	$ 3,743.9	14,741.7	16,222.1	14,237.2
Expenses
Benefits, claims and settlement expenses									8,281.5	9,905.8	8,192.5
Dividends to policyholders									120.2	119.1	123.6
Operating expenses									4,646.5	4,503.9	4,136.7
Total expenses	3,173.5	3,035.6	2,616	4,223.1	3,675.9	4,112.7	3,522.3	3,217.9	13,048.2	14,528.8	12,452.8
Income (loss) before income taxes									1,693.5	1,693.3	1,784.4
Income taxes (benefits)									265	249.2	230.7
Net income (loss)	491.5	235.9	416.1	285	315.3	284.6	392.1	452.1	1,428.5	1,444.1	1,553.7
Net income (loss) attributable to noncontrolling interest									32.7	49.9	7.2
Net income (loss) attributable to Principal Financial Group, Inc.	$ 472.6	$ 236	$ 398.3	$ 288.9	$ 300.9	$ 277.1	$ 386.3	$ 429.9	$ 1,395.8	$ 1,394.2	$ 1,546.5
Earnings per common share
Basic earnings per common share (in dollars per share)	$ 1.72	$ 0.86	$ 1.45	$ 1.05	$ 1.08	$ 0.99	$ 1.38	$ 1.54	$ 5.08	$ 5	$ 5.41
Diluted earnings per common share (in dollars per share)	$ 1.70	$ 0.85	$ 1.45	$ 1.04	$ 1.07	$ 0.98	$ 1.37	$ 1.53	$ 5.05	$ 4.96	$ 5.36

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements of Comprehensive Income
Net income (loss)	$ 1,428.5	$ 1,444.1	$ 1,553.7
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	1,376.5	2,616.1	(1,529.6)
Noncredit component of impairment losses on fixed maturities, available-for-sale		3	26.4
Net unrealized gains (losses) on derivative instruments	(35.2)	(11)	16
Foreign currency translation adjustment	30.6	(78.7)	(287.6)
Net unrecognized postretirement benefit obligation	(24.9)	77.3	(60.9)
Other comprehensive income (loss)	1,347	2,606.7	(1,835.7)
Comprehensive income (loss)	2,775.5	4,050.8	(282)
Comprehensive income (loss) attributable to noncontrolling interest	34.5	53.6	2.7
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ 2,741	$ 3,997.2	$ (284.7)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions		Common stock	Additional paid-in capital	Retained earnings (accumulated deficit)Effects of implementation of accounting change	Retained earnings (accumulated deficit)	Accumulated other comprehensive income (loss)Effects of implementation of accounting change	Accumulated other comprehensive income (loss)	Treasury stock	Noncontrolling interestEffects of implementation of accounting change	Noncontrolling interest	Effects of implementation of accounting change	Total
Balances (ASU 2016-01 - Equity investments) at Dec. 31, 2017				$ 1		$ (1)
Balances (ASU 2014-09 - Revenue recognition) at Dec. 31, 2017				(65)		25.6			$ (0.3)		$ (39.7)
Balances (ASU 2016-16 - Intra-entity asset transfer taxes) at Dec. 31, 2017				8.7							8.7
Balances (ASU 2018-02 - Reclassification of certain tax effects) at Dec. 31, 2017				(77.6)		$ 77.6
Balances at Dec. 31, 2017		$ 4.7	$ 9,925.2		$ 9,482.9		$ 165.5	$ (6,729)		$ 72.6		$ 12,921.9
Increase (decrease) in stockholders' equity
Common stock issued		0.1	63.9									64
Stock-based compensation			84.9		(7.7)					(0.4)		76.8
Treasury stock acquired, common								(671.6)				(671.6)
Dividends to common stockholders					(598.6)							(598.6)
Distributions to noncontrolling interest										(13.5)		(13.5)
Contributions from noncontrolling interest										3.3		3.3
Purchase of subsidiary shares from noncontrolling interest	[1]		(20.6)				(1.6)			(1.8)		(24)
Adjustments to redemption amount of redeemable noncontrolling interest			7.3							(0.3)		7
Net income (loss)	[1]				1,546.5					9.3		1,555.8
Other comprehensive income (loss)	[1]						(1,831.2)			(2.9)		(1,834.1)
Balances (ASU 2016-02 - Leases) at Dec. 31, 2018				4							4
Balances at Dec. 31, 2018		4.8	10,060.7		10,290.2		(1,565.1)	(7,400.6)		66		11,456
Increase (decrease) in stockholders' equity
Common stock issued			37.7									37.7
Stock-based compensation			89.7		(8.1)					0.3		81.9
Treasury stock acquired, common								(281)				(281)
Dividends to common stockholders					(606)							(606)
Distributions to noncontrolling interest										(20.9)		(20.9)
Contributions from noncontrolling interest										8.2		8.2
Purchase of subsidiary shares from noncontrolling interest	[1]		(0.5)							(0.1)		(0.6)
Adjustments to redemption amount of redeemable noncontrolling interest			(5)							(0.4)		(5.4)
Net income (loss)	[1]				1,394.2					16.3		1,410.5
Other comprehensive income (loss)	[1]						2,603			(1.6)		2,601.4
Balances (ASU 2016-13 - CECL) at Dec. 31, 2019				$ (8.4)							$ (8.4)
Balances at Dec. 31, 2019		4.8	10,182.6		11,074.3		1,037.9	(7,681.6)		67.8		14,685.8
Increase (decrease) in stockholders' equity
Common stock issued			42.8									42.8
Stock-based compensation			96.3		(9.2)							87.1
Treasury stock acquired, common								(307)				(307)
Dividends to common stockholders					(614.5)							(614.5)
Distributions to noncontrolling interest										(40.3)		(40.3)
Contributions from noncontrolling interest										6		6
Purchase of subsidiary shares from noncontrolling interest	[1]									(1.4)		(1.4)
Adjustments to redemption amount of redeemable noncontrolling interest			(0.1)							(0.1)		(0.2)
Net income (loss)	[1]				1,395.8					25.2		1,421
Other comprehensive income (loss)	[1]						1,345.2			1.2		1,346.4
Balances at Dec. 31, 2020		$ 4.8	$ 10,321.6		$ 11,838		$ 2,383.1	$ (7,988.6)		$ 58.4		$ 16,617.3
[1]	Excludes amounts attributable to redeemable noncontrolling interest. See Note 13, Stockholders’ Equity, for further details.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net income (loss)	$ 1,428.5	$ 1,444.1	$ 1,553.7
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized capital (gains) losses	(302.6)	52.8	75.4
Depreciation and amortization expense	251.9	226.8	205.1
Amortization of deferred acquisition costs and contract costs	412.9	371.4	277.3
Additions to deferred acquisition costs and contract costs	(499.9)	(515.5)	(443.4)
Stock-based compensation	87.6	82.6	77.4
(Income) loss from equity method investments, net of dividends received	(10.6)	(111.9)	(76)
Changes in:
Accrued investment income	(24)	(50.4)	(28.7)
Net cash flows for trading securities and equity securities with operating intent	144.2	(53.8)	(133.7)
Premiums due and other receivables	16.4	(247.6)	37.8
Contractholder and policyholder liabilities and dividends	1,591.2	3,599.9	3,610.2
Current and deferred income taxes (benefits)	442.5	211.2	274.7
Real estate acquired through operating activities	(16.4)	(64.7)	(89.2)
Real estate sold through operating activities	195.5	136.1	133.6
Other assets and liabilities	(89)	401.1	(282)
Other	110.4	11.1	(35.7)
Net adjustments	2,310.1	4,049.1	3,602.8
Net cash provided by (used in) operating activities	3,738.6	5,493.2	5,156.5
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases	(15,713.4)	(14,137.1)	(13,909.8)
Fixed maturities available-for-sale and equity securities with intent to hold: Sales	3,043.9	2,397.4	3,813.1
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities	8,819.5	7,064.2	6,217.6
Mortgage loans acquired or originated	(3,249.5)	(3,487.7)	(3,447.5)
Mortgage loans sold or repaid	2,477.2	2,335.9	2,228.4
Real estate acquired	(230.6)	(127.5)	(88.1)
Real estate sold	2.3	96.3	63.5
Net (purchases) sales of property and equipment	(108.8)	(132.4)	(92.3)
Purchase of business or interests in subsidiaries, net of cash acquired		(1,208.5)	(184.7)
Net change in other investments	(66.4)	(489.1)	(302.7)
Net cash provided by (used in) investing activities	(5,025.8)	(7,688.5)	(5,702.5)
Financing activities
Issuance of common stock	42.8	37.7	64
Acquisition of treasury stock	(307)	(281)	(671.6)
Payments for financing element derivatives	(30.9)	(26.9)	(65.9)
Purchase of subsidiary shares from noncontrolling interest	(1.4)	(1.7)	(31.1)
Dividends to common stockholders	(614.5)	(606)	(598.6)
Issuance of long-term debt	608.9	504.9	80.8
Principal repayments of long-term debt	(65.8)	(32.2)	(1.3)
Net proceeds from (repayments of) short-term borrowings	(12.6)	57.5	8.5
Investment contract deposits	10,284.4	9,200	8,308.8
Investment contract withdrawals	(8,852.7)	(7,747.7)	(6,589.6)
Net increase (decrease) in banking operation deposits	569.7	623.4	553
Other	0.2	5.7	(4.3)
Net cash provided by (used in) financing activities	1,621.1	1,733.7	1,052.7
Net increase (decrease) in cash and cash equivalents	333.9	(461.6)	506.7
Cash and cash equivalents at beginning of period	2,515.9	2,977.5	2,470.8
Cash and cash equivalents at end of period	2,849.8	2,515.9	2,977.5
Supplemental information:
Cash paid for interest	162.8	157.7	150.2
Cash paid for (received from) income taxes	(172)	(8.5)	$ (96.2)
Supplemental disclosure of non-cash activities:
Lease assets established upon adoption of accounting guidance		168.8
Lease liabilities established upon adoption of accounting guidance		164
Assets received in kind from pension risk transfer transactions	$ 1,325.2	$ 1,225.8

Nature of Operations and Signif

Nature of Operations and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Nature of Operations and Significant Accounting Policies
Nature of Operations and Significant Accounting Policies	1. Nature of Operations and Significant Accounting Policies Description of Business Principal Financial Group, Inc. (“PFG”) is a leader in global investment management offering businesses, individuals and institutional clients a wide range of financial products and services, including retirement, asset management and insurance through our diverse family of financial services companies. Basis of Presentation The accompanying consolidated financial statements include the accounts of PFG and all other entities in which we directly or indirectly have a controlling financial interest as well as those variable interest entities (“VIEs”) in which we are the primary beneficiary. The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). All significant intercompany accounts and transactions have been eliminated. Uncertainties, including those associated with the novel coronavirus ("COVID-19"), may impact our business, results of operations, financial condition and liquidity. Our use of estimates and assumptions affect amounts reported and disclosed and includes, but is not limited to, the fair value of investments in the absence of quoted market values, investment impairments and valuation allowances, the fair value of derivatives, deferred acquisition costs ("DAC") and other actuarial balances, measurement of goodwill and intangible assets, the liability for future policy benefits and claims, the value of pension and other postretirement benefits and accounting for income taxes and the valuation of deferred tax assets. Our estimates and assumptions could change in the future as more information becomes known about the impact of COVID-19. Our results of operations and financial condition may also be impacted by other uncertainties including evolving regulatory, legislative and standard-setter accounting interpretations and guidance. Consolidation We have relationships with various special purpose entities and other legal entities that must be evaluated to determine if the entities meet the criteria of a VIE or a voting interest entity (“VOE”). This assessment is performed by reviewing contractual, ownership and other rights, including involvement of related parties, and requires use of judgment. First, we determine if we hold a variable interest in an entity by assessing if we have the right to receive expected losses and expected residual returns of the entity. If we hold a variable interest, then the entity is assessed to determine if it is a VIE. An entity is a VIE if the equity at risk is not sufficient to support its activities, if the equity holders lack a controlling financial interest or if the entity is structured with non-substantive voting rights. In addition to the previous criteria, if the entity is a limited partnership or similar entity, it is a VIE if the limited partners do not have the power to direct the entity’s most significant activities through substantive kick-out rights or participating rights. A VIE is evaluated to determine the primary beneficiary. The primary beneficiary of a VIE is the enterprise with (1) the power to direct the activities of a VIE that most significantly impact the entity's economic performance and (2) the obligation to absorb losses of the entity or the right to receive benefits from the entity that could potentially be significant to the VIE. When we are the primary beneficiary, we are required to consolidate the entity in our financial statements. We reassess our involvement with VIEs on a quarterly basis. For further information about VIEs, refer to Note 3, Variable Interest Entities. If an entity is not a VIE, it is considered a VOE. VOEs are generally consolidated if we own a greater than 50% voting interest. If we determine our involvement in an entity no longer meets the requirements for consolidation under either the VIE or VOE models, the entity is deconsolidated. Entities in which we have management influence over the operating and financing decisions but are not required to consolidate, other than investments accounted for at fair value under the fair value option, are reported using the equity method. Recent Accounting Pronouncements ​ ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Standards not yet adopted: ​ ​ Targeted improvements to the accounting for long-duration insurance contracts This authoritative guidance updates certain requirements in the accounting for long-duration insurance and annuity contracts. 1. The assumptions used to calculate the liability for future policy benefits on traditional and limited-payment contracts will be reviewed and updated periodically. Cash flow assumptions will be reviewed at least annually and updated when necessary with the impact recognized in net income. Discount rate assumptions are prescribed as the current upper-medium grade (low credit risk) fixed income instrument yield and will be updated quarterly with the impact recognized in other comprehensive income (“OCI”). 2. Market risk benefits, which are contracts or contract features that provide protection to the policyholder from capital market risk and expose us to other-than-nominal capital market risk, are measured at fair value. The periodic change in fair value is recognized in net income with the exception of the periodic change in fair value related to our own nonperformance risk, which is recognized in OCI. 3. DAC and other actuarial balances for all insurance and annuity contracts will be amortized on a constant basis over the expected term of the related contracts. 4. Additional disclosures are required, including disaggregated rollforwards of significant insurance liabilities and other account balances as well as disclosures about significant inputs, judgments, assumptions and methods used in measurement. The guidance for the liability for future policy benefits for traditional and limited-payment contracts and DAC will be applied on a modified retrospective basis; that is, to contracts in force as of the beginning of the earliest period presented based on their existing carrying amounts. An entity may elect to apply the changes retrospectively. The guidance for market risk benefits will be applied retrospectively. Early adoption is permitted. January 1, 2023 Our implementation and evaluation process to date includes, but is not limited to the following: ● ● ● ● ● ● ● ● ● ● As we progress through our implementation, we will be able to better assess the impact to our consolidated financial statements; however, we expect this guidance to significantly change how we account for many of our insurance and annuity products. ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Simplifying the accounting for income taxes This authoritative guidance simplifies the accounting for income taxes by removing certain exceptions, including exceptions related to the incremental approach for intraperiod tax allocation, calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. Also, the guidance clarifies the accounting for franchise taxes, transactions that result in a step-up in the tax basis of goodwill and enacted changes in tax laws or rates. It specifies that an entity is not required to allocate the consolidated amount of current and deferred tax expense to a legal entity that is not subject to tax in its separate financial statements, although an entity may elect to do so. The guidance will be applied based on varying transition methods defined by amendment. Early adoption is permitted. January 1, 2021 This guidance is not expected to have a material impact on our consolidated financial statements. Standards adopted: ​ ​ Facilitation of the effects of reference rate reform on financial reporting This authoritative guidance provides optional expedients and exceptions for contracts and hedging relationships affected by reference rate reform. An entity may elect not to apply certain modification accounting requirements to contracts affected by reference rate reform and instead account for the modified contract as a continuation of the existing contract. Also, an entity may apply optional expedients to continue hedge accounting for hedging relationships in which the critical terms change due to reference rate reform. This guidance eases the financial reporting impacts of reference rate reform on contracts and hedging relationships and is effective until December 31, 2022. March 12, 2020 We adopted the guidance upon issuance prospectively and elected the applicable optional expedients and exceptions for contracts and hedging relationships impacted by reference rate reform through December 31, 2022. The guidance did not have an impact on our consolidated financial statements upon adoption. Goodwill impairment testing This authoritative guidance simplifies how an entity is required to test goodwill for impairment by eliminating Step 2 (which measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill to the carrying amount of that goodwill) from the goodwill impairment test. A goodwill impairment loss will be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Entities will continue to have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. January 1, 2020 This guidance reduces complexity and costs associated with performing a Step 2 test, should one be needed in the future. This guidance did not have a material impact on our consolidated financial statements at adoption. Credit losses This authoritative guidance requires entities to use a current expected credit loss (“CECL”) model to measure impairment for most financial assets that are not recorded at fair value through net income. Under the CECL model, an entity will estimate lifetime expected credit losses considering available relevant information about historical events, current conditions and reasonable and supportable forecasts. The CECL model does not apply to available-for-sale debt securities; however, the credit loss calculation and subsequent recoveries for available-for-sale securities are required to be recorded through an allowance. This guidance also expands the required credit loss disclosures. January 1, 2020 We adopted the guidance using the modified retrospective approach. A cumulative effect adjustment of $8.4 million was recorded as a decrease to retained earnings. We recorded an offsetting increase in the allowance for credit loss for mortgage loans, reinsurance recoverables and commitments and a decrease for deferred tax impacts. See Note 4, Investments, for further details. ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Implementation costs in a cloud computing arrangement that is a service contract This authoritative guidance aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This guidance can be applied either retrospectively or prospectively. January 1, 2019 The effective date of the guidance was January 1, 2020; however, we elected to early-adopt this guidance on a prospective basis, effective January 1, 2019. This guidance did not have a material impact on our consolidated financial statements. Nonemployee share-based payment accounting This authoritative guidance simplifies the accounting for share-based payments to nonemployees by generally aligning it with the accounting for share-based payments to employees. Under the guidance, the measurement of equity-classified nonemployee awards will be fixed at the grant date, where previously the measurement was fixed at performance completion date. The guidance will be applied to equity-classified nonemployee awards for which a measurement date has not been established as of the date of adoption. January 1, 2019 This guidance did not have a material impact on our consolidated financial statements. ​ Leases This authoritative guidance requires lessee recognition of lease assets and lease liabilities on the consolidated statements of financial position. The concept of an operating lease, where the lease assets and liabilities are not reported on the consolidated statements of financial position, is eliminated under the new guidance. For lessors, the guidance modifies lease classification criteria and accounting for certain types of leases. Other key aspects of the guidance relate to the removal of the current real estate-specific guidance and new presentation and disclosure requirements. Lessees and lessors are required to recognize and measure leases using a modified retrospective approach, which includes certain optional practical expedients that may be elected. We elected the alternative transition method, which allows entities to initially apply the new standard at the adoption date and recognize a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption. January 1, 2019 We adopted the guidance using the modified retrospective approach. A cumulative effect adjustment of $4.0 million was recorded as an increase to retained earnings. See Note 12, Contingencies, Guarantees, Indemnifications and Leases, for further details. Targeted improvements to accounting for hedging activities This authoritative guidance updated certain recognition and measurement requirements for hedge accounting. The objective of the guidance is to more closely align the economics of a company’s risk management activities in its financial results and reduce the complexity of applying hedge accounting. The updates included the expansion of hedging strategies that are eligible for hedge accounting, elimination of the separate measurement and reporting of hedge ineffectiveness, presentation of the changes in the fair value of the hedging instrument in the same consolidated statement of operations line as the earnings effect of the hedged item and simplification of hedge effectiveness assessments. This guidance also included new disclosures. January 1, 2019 This guidance did not have a material impact on our consolidated financial statements. See Note 5, Derivative Financial Instruments, for further details. ​ ​ ​ ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Premium amortization on purchased callable debt securities This authoritative guidance applies to entities that hold certain non-contingently callable debt securities, where the amortized cost basis is at a premium to the price repayable by the issuer at the earliest call date. Under the guidance the premium will be amortized to the first call date. January 1, 2019 This guidance did not have a material impact on our consolidated financial statements. Reclassification of certain tax effects from accumulated other comprehensive income This authoritative guidance permits a reclassification from accumulated other comprehensive income (“AOCI”) to retained earnings for the stranded tax effects resulting from U.S. tax legislation enacted on December 22, 2017, which is referred to as the ‘‘Tax Cuts and Jobs Act’’ (‘‘U.S. tax reform’’). The amount of that reclassification includes the change in corporate income tax rate, as well as an election to include other income tax effects related to the application of U.S. tax reform. The guidance also requires disclosures about stranded tax effects. January 1, 2018 The effective date of the guidance was January 1, 2019; however, we elected to early adopt the guidance. The guidance was applied at the beginning of the period of adoption and comparative periods were not restated. We reclassified the stranded tax effects in AOCI resulting from U.S. tax reform, which includes the change in corporate income tax rate and an election to reclassify the tax effects of the one-time deemed repatriation tax. A reclassification of $77.6 million was recorded as an increase to AOCI and a decrease to retained earnings. Revenue recognition This authoritative guidance replaces all general and most industry specific revenue recognition guidance currently prescribed by U.S. GAAP. The core principle is that an entity recognizes revenue to reflect the transfer of a promised good or service to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for that good or service. This guidance also provides clarification on when an entity is a principal or an agent in a transaction. In addition, the guidance updates the accounting for certain costs associated with obtaining and fulfilling a customer contract. The guidance may be applied using one of the following two methods: (1) retrospectively to each prior reporting period presented, or (2) retrospectively with the cumulative effect of initially applying the standard recognized at the date of initial application. January 1, 2018 We adopted the guidance using the modified retrospective approach. The guidance did not have a material impact on our consolidated financial statements. A cumulative effect adjustment of $39.7 million was recorded as a decrease to total stockholders' equity. See Note 17, Revenues from Contracts with Customers, for further details. Income tax - intra-entity transfers of assets This authoritative guidance requires entities to recognize current and deferred income tax resulting from an intra-entity asset transfer when the transfer occurs. Prior to issuance of this guidance, U.S. GAAP did not allow recognition of income tax consequences until the asset had been sold to a third party. This guidance requires adoption through a cumulative effect adjustment to the consolidated statements of financial position as of the beginning of the fiscal year of adoption. January 1, 2018 ​ We adopted the guidance using the modified retrospective approach. A cumulative effect adjustment of $8.7 million was recorded as an increase to retained earnings. In addition, other assets and deferred income taxes decreased $21.1 million and $29.8 million, respectively, due to the adoption of this guidance. ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Financial instruments - recognition and measurement January 1, 2018 We adopted this guidance using the modified retrospective approach. A cumulative effect adjustment of $1.0 million was recorded as a decrease to AOCI and a corresponding increase to retained earnings. The guidance did not have a material impact on our consolidated financial statements. See Note 4, Investments, for further details. Nonfinancial asset derecognition and partial sales of nonfinancial assets This authoritative guidance clarifies the scope of the recently established guidance on nonfinancial asset derecognition and the accounting for partial sales of nonfinancial assets. The guidance conforms the derecognition guidance on nonfinancial assets with the model for transactions in the new revenue recognition standard. January 1, 2018 The guidance did not have a material impact on our consolidated financial statements. Presentation of net periodic pension cost and net periodic postretirement benefit cost This authoritative guidance requires that an employer disaggregate the service cost component from the other components of net benefit cost. The guidance also provides explicit guidance on the presentation of the service cost component and the other components of net benefit cost in the consolidated statements of operations and allows only the service cost component of net benefit cost to be eligible for capitalization. January 1, 2018 The guidance did not have a material impact on our consolidated financial statements. Definition of a business This authoritative guidance clarifies the definition of a business to assist with evaluating when transactions involving an integrated set of assets and activities (a “set”) should be accounted for as acquisitions or disposals of assets or businesses. The guidance requires that when substantially all of the fair value of the gross assets acquired or disposed of is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. The guidance also requires a set to include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output to be considered a business. Lastly, the guidance removes the evaluation of whether a market participant could replace missing elements and narrows the definition of outputs by more closely aligning it with how outputs are described in the revenue recognition guidance. The guidance will be applied prospectively. January 1, 2018 The guidance did not have a material impact on our consolidated financial statements. ​ When we adopt new accounting standards, we have a process in place to perform a thorough review of the pronouncement, identify the financial statement and system impacts and create an implementation plan among our impacted business units to ensure we are compliant with the pronouncement on the date of adoption. This includes having effective processes and controls in place to support the reported amounts. Each of the standards listed above is in varying stages in our implementation process based on its issuance and adoption dates. We are on track to implement guidance by the respective effective dates. Use of Estimates in the Preparation of Financial Statements The preparation of our consolidated financial statements and accompanying notes requires management to make estimates and assumptions that affect the amounts reported and disclosed. These estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed in the consolidated financial statements and accompanying notes. The most critical estimates include those used in determining: ● the fair value of investments in the absence of quoted market values; ● investment impairments and valuation allowances; ● the fair value of and accounting for derivatives; ● the DAC and other actuarial balances where the amortization is based on estimated gross profits (“EGPs”); ● the measurement of goodwill, indefinite lived intangible assets, finite lived intangible assets and related impairments or amortization, if any; ● the liability for future policy benefits and claims; ● the value of our pension and other postretirement benefit obligations and ● accounting for income taxes and the valuation of deferred tax assets. A description of such critical estimates is incorporated within the discussion of the related accounting policies that follow. In applying these policies, management makes subjective and complex judgments that frequently require estimates about matters that are inherently uncertain. Actual results could differ from these estimates. Closed Block Principal Life Insurance Company (“Principal Life”) operates a closed block (“Closed Block”) for the benefit of individual participating dividend-paying policies in force at the time of the 1998 mutual insurance holding company (“MIHC”) formation. See Note 6, Closed Block, for further details. Cash and Cash Equivalents Cash and cash equivalents include cash on hand, money market instruments and other debt issues with a maturity date of three months or less when purchased. Investments Fixed maturities include bonds, asset-backed securities (“ABS”), redeemable preferred stock and certain non-redeemable preferred securities. Equity securities include mutual funds, common stock, non-redeemable preferred stock and required regulatory investments. We classify fixed maturities as either available-for-sale or trading at the time of the purchase and, accordingly, carry them at fair value. Equity securities are also carried at fair value. See Note 14, Fair Value Measurements, for methodologies related to the determination of fair value. Unrealized gains and losses related to fixed maturities, available-for-sale, excluding those in fair value hedging relationships, are reflected in stockholders' equity, net of adjustments associated with DAC and related actuarial balances, derivatives in cash flow hedge relationships and applicable income taxes. Mark-to-market adjustments on equity securities, unrealized gains and losses related to hedged portions of fixed maturities, available-for-sale in fair value hedging relationships prior to 2019 and mark-to-market adjustments on certain fixed maturities, trading are reflected in net realized capital gains (losses). Beginning in 2019, unrealized gains and losses related to hedged portions of fixed maturities, available-for-sale in fair value hedging relationships are reflected in net investment income. Mark-to-market adjustments related to certain securities carried at fair value with an investment objective to realize economic value through mark-to-market changes are reflected in net investment income. The amortized cost of fixed maturities includes cost adjusted for amortization of premiums and discounts, computed using the interest method. The amortized cost of fixed maturities, available-for-sale is adjusted for changes in fair value of the hedged portions of securities in fair value hedging relationships and excludes accrued interest receivable. Accrued interest receivable is reported in accrued investment income on the consolidated statements of financial position. Beginning in 2020, fixed maturities, available-for-sale are subject to an allowance for credit loss and changes in the allowance are reported in net income as a component of net realized capital gains (losses). Prior to 2020, the amortized cost of fixed maturities classified as available-for-sale was adjusted for declines in value that were other than temporary. Prior to 2020, impairments in value deemed to be other than temporary were primarily reported in net income as a component of net realized capital gains (losses), with noncredit impairment losses for certain fixed maturities, available-for-sale reported in OCI. Interest income, as well as prepayment fees and the amortization of the related premium or discount, is reported in net investment income. For loan-backed and structured securities, we recognize income using a constant effective yield based on currently anticipated cash flows. Commercial and residential mortgage loans are generally reported at cost adjusted for amortization of premiums and accrual of discounts, computed using the interest method and net of valuation allowances. Amortized cost excludes accrued interest receivable. Interest income is accrued on the principal amount of the loan based on the loan’s contractual interest rate. Interest income, as well as prepayment of fees and the amortization of the related premium or discount, is reported in net investment income on the consolidated statements of operations. Accrued interest receivable is reported in accrued investment income on the consolidated statements of financial position. Any changes in the loan valuation allowances are reported in net realized capital gains (losses) on the consolidated statements of operations. See Note 4, Investments, for further details of our valuation allowance. Our commercial and residential mortgage loan portfolios can include loans that have been modified. We assess loan modifications on a case-by-case basis to evaluate whether a troubled debt restructuring (“TDR”) has occurred. In response to COVID-19, the Coronavirus Aid, Relief and Economic Security Act, which was subsequently amended by the Consolidated Appropriations Act, 2021, (collectively the “CARES Act”) provides a temporary suspension of TDR accounting for certain COVID-19 related loan modifications where the loan was not more than 30 days past due as of December 31, 2019. We elected the TDR relief in the CARES Act beginning in the second quarter of 2020. The CARES Act TDR relief does not apply to modifications completed subsequent to the earlier of 60 days after the national emergency related to COVID-19 ends, or January 1, 2022. In addition, the Interagency Statement on Loan Modifications and Reporting for Financial Institutions Working with Customers Affected by the Coronavirus (As Revised on April 7, 2020) (“Interagency Statement”) provides additional guidance to determine if a short-term COVID-19 related loan modification is a TDR. We consider the CARES Act and the Interagency Statement when assessing loan modifications to determine whether a TDR has occurred. See Note 4, Investments, under the caption “Mortgage Loan Modifications” for further details. Real estate investments are reported at cost less accumulated depreciation. The initial cost bases of properties acquired through loan foreclosures are the lower of the fair market values of the properties at the time of foreclosure or the outstanding loan balance. Buildings and land improvements are generally depreciated on the straight-line method over the estimated useful life of improvements and tenant improvement costs are depreciated on the straight-line method over the term of the related lease. We recognize impairment losses for properties when indicators of impairment are present and a property's expected undiscounted cash flows are not sufficient to recover the property's carrying value. In such cases, the cost basis of the property is reduced to fair value. Real estate expected to be disposed is carried at the lower of cost or fair value, less cost to sell, with valuation allowances established accordingly and depreciation no longer recognized. The carrying amount of real estate held for sale was $2.0 million and $169.8 million as of December 31, 2020 and 2019, respectively. Any impairment losses and any changes in valuation allowances are reported in net income. Net realized capital gains and losses on sales of investments are determined on the basis of specific identification. In general, in addition to realized capital gains and losses on investment sales and periodic settlements on derivatives not designated as hedges, we report gains and losses related to the following in net realized capital gains (losses) on the consolidated statements of operations: mark-to-market adjustments on equity securities, mark-to-market adjustments on certain fixed maturities, trading, mark-to-market adjustments on sponsored investment funds, mark-to-market adjustments on derivatives not designated as hedges, cash flow hedge gains (losses) when the hedged item impacts realized capital gains (losses), changes in the valuation allowance for fixed maturities, available-for-sale and certain financing receivables, impairments of real estate held for investment, impairments of equity method investments and, prior to 2020, other-than-temporary impairments of securities and subsequent realized recoveries. Investment gains and losses on sales of certain real estate held for sale due to investment strategy and mark-to-market adjustments on certain securities carried at fair value with an investment objective to realize economic value through mark-to-market changes are reported as net investment income and are excluded from net realized capital gains (losses). Policy loans and certain other investments are reported at cost. Interests in unconsolidated entities, joint ventures and partnerships are generally accounted for using the equity method. We have other investments reported at fair value or for which the fair value option has been elected in prior periods. See Note 14, Fair Value Measurements, for detail on these investments. Derivatives Overview Derivatives are financial instruments whose values are derived from interest rates, foreign exchange rates, financial indices or the values of securities. Derivatives generally used by us include swaps, options, futures and forwards. Derivative positions are either assets or liabilities in the consolidated statements of financial position and are measured at fair value, generally by obtaining quoted market prices or through the use of pricing models. See Note 14, Fair Value Measurements, for policies related to the determination of fair value. Fair values can be affected by changes in interest rates, foreign exchange rates, financial indices, values of securities, credit spreads, and market volatility and liquidity. Accounting and Financial Statement Presentation We designate derivatives as either: (a) a hedge of the exposure to changes in the fair value of a recognized asset or liability or an unrecognized firm commitment, including

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Other Intangible Assets
Goodwill and Other Intangible Assets	2. Goodwill and Other Intangible Assets Goodwill The changes in the carrying amount of goodwill reported in our segments were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement Principal ​ ​ U.S. ​ ​ ​ ​ ​ ​ and Income ​ Global ​ Principal ​ Insurance ​ ​ ​ ​ ​ ​ ​ ​ ​ Solutions ​ Investors ​ International ​ Solutions ​ Corporate ​ Consolidated ​ ​ ​ (in millions) ​ Balance as of January 1, 2019 ​ $ 57.4 ​ $ 307.3 ​ $ 676.6 ​ $ 56.6 ​ $ 2.1 ​ $ 1,100.0 ​ Goodwill from acquisitions (1) ​ ​ 618.5 ​ ​ 6.5 ​ ​ — ​ ​ — ​ ​ (1.1) ​ ​ 623.9 ​ Foreign currency ​ — ​ 1.5 ​ (31.6) ​ — ​ — ​ (30.1) ​ Other (2) ​ ​ — ​ ​ 2.2 ​ ​ (2.2) ​ ​ — ​ ​ — ​ ​ — ​ Balance as of December 31, 2019 ​ ​ 675.9 ​ ​ 317.5 ​ ​ 642.8 ​ ​ 56.6 ​ ​ 1.0 ​ ​ 1,693.8 ​ Foreign currency ​ ​ — ​ ​ 3.4 ​ ​ 13.8 ​ ​ — ​ ​ — ​ ​ 17.2 ​ Balance as of December 31, 2020 ​ $ 675.9 ​ $ 320.9 ​ $ 656.6 ​ $ 56.6 ​ $ 1.0 ​ $ 1,711.0 ​ (1) Relates to the acquisitions of: a) Wells Fargo Institutional Retirement & Trust business consolidated within our Retirement and Income Solutions segment; b) a consolidating interest in Finisterre Capital LLP within our Principal Global Investors segment for which we previously held an equity method interest; c) measurement period adjustments related to RobustWealth within our Principal Global Investors segment and Corporate segment. (2) Relates to the movement of our investment management company in Brazil from the Principal International segment to the Principal Global Investors segment. On July 1, 2019, we completed the purchase of the Institutional Retirement & Trust business of Wells Fargo Bank, N.A. (the “Acquired Business”), which includes defined contribution, defined benefit, executive deferred compensation, employee stock ownership plans, institutional trust and custody, and institutional asset advisory businesses. The purchase price consisted of $1.2 billion cash paid at closing, which was funded with available cash and debt financing. See “Note 9, Debt” for further information on the debt financing. The fair value of the net assets acquired primarily relates to intangible assets. Of the acquired intangible assets, $618.5 million was assigned to goodwill and is not subject to amortization. The goodwill is largely related to the opportunities to realize substantial revenue and cost synergies while achieving scale in operations. Of the remaining acquired intangible assets, $510.3 million was assigned to customer relationships, which are subject to amortization over a 23-year useful life, and $35.4 million was assigned to technology, which is subject to amortization over a 6-year useful life. Finite Lived Intangible Assets Amortized intangible assets primarily relate to customer relationship intangibles associated with the Acquired Business and previous acquisitions in Chile, Mexico and Hong Kong. The finite lived intangible assets that continue to be subject to amortization over a weighted average remaining expected life of 17 years were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 2019 ​ ​ (in millions) ​ Gross carrying value ​ $ 1,338.2 ​ $ 1,346.3 ​ Accumulated amortization ​ 405.6 ​ ​ 343.2 ​ Net carrying value ​ $ 932.6 ​ $ 1,003.1 ​ ​ During 2020, we fully amortized other finite lived intangible assets of $18.7 million. The amortization expense for intangible assets with finite useful lives was $73.5 million, $62.8 million and $53.9 million for 2020, 2019 and 2018, respectively. As of December 31, 2020, the estimated amortization expense for the next five years is as follows (in millions): ​ ​ ​ ​ ​ ​ Year ending December 31: ​ ​ 2021 ​ $ 75.1 ​ 2022 ​ ​ 73.9 ​ 2023 ​ ​ 71.2 ​ 2024 ​ ​ 70.0 ​ 2025 ​ ​ 68.2 ​ ​ Indefinite Lived Intangible Assets The net carrying amount of unamortized indefinite lived intangible assets was $790.4 million and $783.6 million as of December 31, 2020 and 2019, respectively. As of both December 31, 2020 and 2019, $608.0 million relates to investment management contracts associated with our acquisition of WM Advisors, Inc. in 2006. The remaining balance primarily relates to the trade name intangible associated with our acquisition of Administradora de Fondos de Pensiones Cuprum S.A. ("Cuprum") in 2013.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2020
Variable Interest Entities
Variable Interest Entities	3. Variable Interest Entities We have relationships with various types of entities which may be VIEs. Certain VIEs are consolidated in our financial results. See Note 1, Nature of Operations and Significant Accounting Policies, under the caption “Consolidation” for further details of our consolidation accounting policies. We did not provide financial or other support to investees designated as VIEs for the periods ended December 31, 2020 and December 31, 2019. Consolidated Variable Interest Entities Grantor Trust We contributed undated subordinated floating rate notes to a grantor trust. The trust separated its cash flows by issuing an interest-only certificate and a residual certificate related to each note contributed. Each interest-only certificate entitled the holder to interest on the stated note for a specified term, while the residual certificate entitled the holder to interest payments subsequent to the term of the interest-only certificate and to all principal payments. We retained the interest-only certificates and the residual certificates were subsequently sold to third parties. We determined the grantor trust was a VIE due to insufficient equity to sustain it. We determined we were the primary beneficiary as a result of our contribution of securities into the trust and our significant continuing interest in the trust. The certificates matured in the second quarter of 2020. Mandatory Retirement Savings Funds We hold an equity interest in Chilean mandatory privatized social security funds in which we provide asset management services. We determined the mandatory privatized social security funds, which also include contributions for voluntary pension savings, voluntary non-pension savings and compensation savings accounts, are VIEs. This is because the equity holders as a group lack the power, due to voting rights or similar rights, to direct the activities of the entity that most significantly impact the entity’s economic performance and also because equity investors are protected from below-average market investment returns relative to the industry's return, due to a regulatory guarantee that we provide. Further we concluded we are the primary beneficiary through our power to make decisions and our significant variable interest in the funds. The purpose of the funds, which reside in legally segregated entities, is to provide long-term retirement savings. The obligation to the customer is directly related to the assets held in the funds and, as such, we present the assets as separate account assets and the obligation as separate account liabilities within our consolidated statements of financial position. Principal International Hong Kong offers retirement pension schemes in which we provide trustee, administration and asset management services to employers and employees under the Hong Kong Mandatory Provident Fund and Occupational Retirement Schemes Ordinance pension schemes. Each pension scheme has various guaranteed and non-guaranteed constituent funds, or investment options, in which customers can invest their money. The guaranteed funds provide either a guaranteed rate of return to the customer or a minimum guarantee on withdrawals under certain qualifying events. We determined the guaranteed funds are VIEs due to the fact the equity holders, as a group, lack the obligation to absorb expected losses due to the guarantee we provide. We concluded we are the primary beneficiary because we have the power to make decisions and to receive benefits and the obligation to absorb losses that could be potentially significant to the VIE. Therefore, we consolidate the underlying assets and liabilities of the funds and present as separate accounts or within the general account, depending on the terms of the guarantee. Real Estate We invest in several real estate limited partnerships and limited liability companies. The entities invest in real estate properties. Certain of these entities are VIEs based on the combination of our significant economic interest and related voting rights. We determined we are the primary beneficiary as a result of our power to control the entities through our significant ownership. Due to the nature of these real estate investments, the investment balance will fluctuate as we purchase and sell interests in the entities and as capital expenditures are made to improve the underlying real estate. Sponsored Investment Funds We sponsor and invest in certain investment funds for which we provide asset management services. Although our asset management fee is commensurate with the services provided and consistent with fees for similar services negotiated at arms-length, we have a variable interest for funds where our other interests are more than insignificant. The funds are VIEs as the equity holders lack power through voting rights to direct the activities of the entity that most significantly impact its economic performance. We determined we are the primary beneficiary of the VIEs where our interest in the entity is more than insignificant and we are the asset manager. We also invested in certain series of another investment fund. These series were VIEs as the equity holders of each series lacked the power to direct the most significant activities of the VIE. We determined we were the primary beneficiary of these series as our interest was more than insignificant and collectively we had the power to direct the most significant activities of the fund. These investments were redeemed in the third quarter of 2020. Residential Mortgage Loans We invested in an ABS trust. The trust issued various collateralized mortgage obligation certificates and purchased residential mortgage loans. The trust is considered a VIE due to insufficient equity to sustain itself. We concluded that we are the primary beneficiary as we have purchased substantially all of the certificates and have the obligation to absorb losses that could potentially be significant to the VIE. Assets and Liabilities of Consolidated Variable Interest Entities The carrying amounts of our consolidated VIE assets, which can only be used to settle obligations of consolidated VIEs, and liabilities of consolidated VIEs for which creditors do not have recourse were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ ​ Total ​ Total ​ Total ​ Total ​ ​ assets liabilities assets liabilities ​ ​ ​ (in millions) ​ Grantor trust (1) ​ $ — ​ $ — ​ $ 99.9 ​ $ 98.6 ​ Mandatory retirement savings funds (2) ​ 41,995.2 ​ 41,527.9 ​ 39,891.1 ​ 39,524.9 ​ Real estate (3) ​ 499.0 ​ 21.3 ​ 479.7 ​ 88.0 ​ Sponsored investment funds (4) ​ 419.5 ​ 3.2 ​ 331.4 ​ 2.2 ​ Residential mortgage loans (5) ​ ​ 319.8 ​ ​ — ​ ​ — ​ ​ — ​ Total ​ $ 43,233.5 ​ $ 41,552.4 ​ $ 40,802.1 ​ $ 39,713.7 ​ (1) The assets of the grantor trust were primarily fixed maturities, available-for-sale. The liabilities were primarily other liabilities that reflected an embedded derivative of the forecasted transaction to deliver the underlying securities. (2) The assets of the mandatory retirement savings funds primarily include separate account assets and equity securities. The liabilities primarily include separate account liabilities and contractholder funds. (3) The assets of the real estate VIEs primarily include real estate and cash. Liabilities primarily include other liabilities and included long-term debt as of December 31, 2019. (4) The assets of sponsored investment funds are primarily fixed maturities and equity securities, certain of which are reported with other investments, and cash. The consolidated statements of financial position included a $226.8 million and $215.4 million redeemable noncontrolling interest for sponsored investment funds as of December 31, 2020 and December 31, 2019, respectively. (5) The assets of the residential mortgage loans VIE primarily include residential mortgage loans. The liabilities of the VIE are eliminated in our consolidated results. Unconsolidated Variable Interest Entities We hold a variable interest in a number of VIEs where we are not the primary beneficiary. Our investments in these VIEs are reported in fixed maturities, available-for-sale; fixed maturities, trading; equity securities and other investments in the consolidated statements of financial position and are described below. Unconsolidated VIEs include certain commercial mortgage-backed securities (“CMBS”), residential mortgage-backed pass-through securities ("RMBS") and other ABS. All of these entities were deemed VIEs because the equity within these entities is insufficient to sustain them. We determined we are not the primary beneficiary in the entities within these categories of investments. This determination was based primarily on the fact we do not own the class of security that controls the unilateral right to replace the special servicer or equivalent function. We invest in cash collateralized debt obligations, collateralized bond obligations, collateralized loan obligations and other collateralized structures, which are VIEs due to insufficient equity to sustain the entities. We have determined we are not the primary beneficiary of these entities primarily because we do not control the economic performance of the entities and were not involved with the design of the entities or because we do not have a potentially significant variable interest in the entities for which we are the asset manager. We have invested in various VIE trusts and similar entities as a debt holder. Most of these entities are classified as VIEs due to insufficient equity to sustain them. In addition, we have an entity classified as a VIE based on the combination of our significant economic interest and lack of voting rights. We have determined we are not the primary beneficiary primarily because we do not control the economic performance of the entities and were not involved with the design of the entities. We have invested in partnerships and other funds, which are classified as VIEs. The entities are VIEs as equity holders lack the power to control the most significant activities of the entities because the equity holders do not have either the ability by a simple majority to exercise substantive kick-out rights or substantive participating rights. We have determined we are not the primary beneficiary because we do not have the power to direct the most significant activities of the entities. As previously discussed, we sponsor and invest in certain investment funds that are VIEs. We determined we are not the primary beneficiary of the VIEs for which we are the asset manager but do not have a potentially significant variable interest in the funds. We hold an equity interest in Mexican mandatory privatized social security funds in which we provide asset management services. Our equity interest in the funds is considered a variable interest. We concluded the funds are VIEs because the equity holders as a group lack decision-making ability through their voting rights. We are not the primary beneficiary of the VIEs because although we, as the asset manager, have the power to direct the activities of the VIEs, we do not have a potentially significant variable interest in the funds. The carrying value and maximum loss exposure for our unconsolidated VIEs were as follows: ​ ​ ​ ​ ​ Maximum exposure to ​ ​ Asset carrying value loss (1) ​ ​ (in millions) ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 296.9 ​ $ 285.7 ​ Residential mortgage-backed pass-through securities ​ ​ 2,986.8 ​ ​ 2,857.6 ​ Commercial mortgage-backed securities ​ ​ 4,942.3 ​ ​ 4,741.2 ​ Collateralized debt obligations (2) ​ 4,027.5 ​ 4,045.9 ​ Other debt obligations ​ 7,045.9 ​ 6,832.6 ​ Fixed maturities, trading: ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed pass-through securities ​ 190.5 ​ 190.5 ​ Commercial mortgage-backed securities ​ 27.1 ​ 27.1 ​ Collateralized debt obligations (2) ​ ​ 20.6 ​ ​ 20.6 ​ Other debt obligations ​ ​ 9.4 ​ ​ 9.4 ​ Equity securities ​ ​ 121.7 ​ ​ 121.7 ​ Other investments: ​ ​ ​ ​ ​ ​ ​ Other limited partnership and fund interests (3) ​ 999.1 ​ 1,739.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 238.2 ​ $ 225.7 ​ Residential mortgage-backed pass-through securities ​ ​ 2,982.4 ​ ​ 2,913.9 ​ Commercial mortgage-backed securities ​ ​ 4,850.2 ​ ​ 4,746.6 ​ Collateralized debt obligations (2) ​ 3,215.3 ​ 3,226.7 ​ Other debt obligations ​ 8,191.1 ​ 8,076.4 ​ Fixed maturities, trading: ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed pass-through securities ​ 282.3 ​ 282.3 ​ Commercial mortgage-backed securities ​ 28.2 ​ 28.2 ​ Collateralized debt obligations (2) ​ ​ 20.9 ​ ​ 20.9 ​ Other debt obligations ​ ​ 13.2 ​ ​ 13.2 ​ Equity securities ​ ​ 123.2 ​ ​ 123.2 ​ Other investments: ​ ​ ​ ​ ​ ​ ​ Other limited partnership and fund interests (3) ​ 911.9 ​ 1,467.0 ​ (1) Our risk of loss is limited to our initial investment measured at amortized cost for fixed maturities, available-for-sale. Our risk of loss is limited to our investment measured at fair value for our fixed maturities, trading and equity securities. Our risk of loss is limited to our carrying value plus any unfunded commitments and/or guarantees and similar provisions for our other investments. Unfunded commitments are not liabilities on our consolidated statements of financial position because we are only required to fund additional equity when called upon to do so by the general partner or investment manager . (2) Primarily consists of collateralized loan obligations backed by secured corporate loans. (3) As of December 31, 2020 and December 31, 2019, the maximum exposure to loss for other limited partnership and fund interests includes $141.2 million and $129.1 million, respectively, of debt within certain of our managed international real estate funds that is fully secured by assets whose value exceeds the amount of the debt, but also includes recourse to the investment manager. Money Market Funds We are the investment manager for certain money market mutual funds. These types of funds are exempt from assessment under any consolidation model due to a scope exception for money market funds registered under Rule 2a-7 of the Investment Company Act of 1940 or similar funds. As of December 31, 2020 and December 31, 2019, money market mutual funds we manage held $4.4 billion and $4.0 billion in total assets, respectively. We have no contractual obligation to contribute to these funds; however, we provide support through the waiver of fees and through expense reimbursements. The amount of fees waived and expenses reimbursed was insignificant.

Investments

Investments	12 Months Ended
	Dec. 31, 2020
Investments
Investments	4. Investments Fixed Maturities and Equity Securities Available -for-sale securities were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ Allowance ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ for credit ​ ​ ​ ​ cost (1) gains losses loss Fair value ​ ​ (in millions) ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 1,893.1 ​ $ 228.9 ​ $ 10.5 ​ $ — ​ $ 2,111.5 ​ Non-U.S. governments ​ 881.6 ​ 192.1 ​ — ​ — ​ 1,073.7 ​ States and political subdivisions ​ 8,004.9 ​ 1,175.5 ​ 12.6 ​ — ​ 9,167.8 ​ Corporate ​ 41,289.9 ​ 6,160.9 ​ 95.1 ​ 0.9 ​ 47,354.8 ​ Residential mortgage-backed pass-through securities ​ 2,857.6 ​ 129.4 ​ 0.2 ​ — ​ 2,986.8 ​ Commercial mortgage-backed securities ​ 4,741.2 ​ 241.3 ​ 35.9 ​ 4.3 ​ 4,942.3 ​ Collateralized debt obligations (2) ​ 4,045.9 ​ 8.7 ​ 24.9 ​ 2.2 ​ 4,027.5 ​ Other debt obligations ​ 6,832.6 ​ 243.2 ​ 29.9 ​ — ​ 7,045.9 ​ Total fixed maturities, available-for-sale ​ $ 70,546.8 ​ $ 8,380.0 ​ $ 209.1 ​ $ 7.4 ​ $ 78,710.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other-than- ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ temporary ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ ​ ​ ​ impairments in ​ ​ ​ cost ​ gains ​ losses ​ Fair value ​ OCI (3) ​ ​ ​ (in millions) ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 1,627.0 ​ $ 100.2 ​ $ 3.0 ​ $ 1,724.2 ​ $ — ​ Non-U.S. governments ​ 852.3 ​ 144.1 ​ 0.2 ​ 996.2 ​ — ​ States and political subdivisions ​ 6,857.1 ​ 644.5 ​ 11.6 ​ 7,490.0 ​ — ​ Corporate ​ 36,993.1 ​ 3,706.5 ​ 52.2 ​ 40,647.4 ​ — ​ Residential mortgage-backed pass-through securities ​ 2,913.9 ​ 72.3 ​ 3.8 ​ 2,982.4 ​ — ​ Commercial mortgage-backed securities ​ 4,746.6 ​ 127.6 ​ 24.0 ​ 4,850.2 ​ 15.8 ​ Collateralized debt obligations (2) ​ 3,226.7 ​ 2.9 ​ 14.3 ​ 3,215.3 ​ 0.9 ​ Other debt obligations ​ 8,085.8 ​ 129.6 ​ 14.9 ​ 8,200.5 ​ 31.7 ​ Total fixed maturities, available-for-sale ​ $ 65,302.5 ​ $ 4,927.7 ​ $ 124.0 ​ $ 70,106.2 ​ $ 48.4 ​ (1) Amortized cost excludes accrued interest receivable of $552.5 million as of December 31, 2020. (2) Primarily consists of collateralized loan obligations backed by secured corporate loans. (3) Excludes $62.3 million as of December 31, 2019, of net unrealized gains on impaired fixed maturities, available-for-sale related to changes in fair value subsequent to the impairment date, which are included in gross unrealized gains and gross unrealized losses. ​ The amortized cost and fair value of fixed maturities, available-for-sale as of December 31, 2020, by expected maturity, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized cost Fair value ​ ​ (in millions) ​ Due in one year or less ​ $ 2,336.5 ​ $ 2,372.9 ​ Due after one year through five years ​ ​ 10,831.5 ​ ​ 11,570.0 ​ Due after five years through ten years ​ ​ 14,032.7 ​ ​ 15,601.5 ​ Due after ten years ​ ​ 24,868.8 ​ ​ 30,163.4 ​ Subtotal ​ ​ 52,069.5 ​ ​ 59,707.8 ​ Mortgage-backed and other asset-backed securities ​ ​ 18,477.3 ​ ​ 19,002.5 ​ Total ​ $ 70,546.8 ​ $ 78,710.3 ​ ​ Actual maturities may differ because borrowers may have the right to call or prepay obligations. Our portfolio is diversified by industry, issuer and asset class. Credit concentrations are managed to established limits. Net Investment Income Major components of net investment income were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Fixed maturities, available-for-sale (1) ​ $ 2,660.5 ​ $ 2,606.0 ​ $ 2,479.9 ​ Fixed maturities, trading ​ ​ 18.7 ​ 23.8 ​ 26.4 ​ Equity securities ​ ​ 62.8 ​ ​ 110.5 ​ ​ 38.8 ​ Mortgage loans ​ ​ 724.7 ​ 707.0 ​ 641.4 ​ Real estate ​ ​ 180.8 ​ 191.1 ​ 158.8 ​ Policy loans ​ ​ 41.6 ​ 44.0 ​ 45.0 ​ Cash and cash equivalents ​ ​ 17.4 ​ 65.3 ​ 56.2 ​ Derivatives (1) ​ ​ (1.8) ​ (2.0) ​ 0.1 ​ Other ​ ​ 296.5 ​ 370.8 ​ 285.0 ​ Total ​ ​ 4,001.2 ​ 4,116.5 ​ 3,731.6 ​ Investment expenses ​ ​ (110.6) ​ (118.1) ​ (102.4) ​ Net investment income ​ $ 3,890.6 ​ $ 3,998.4 ​ $ 3,629.2 ​ (1) Upon adoption of authoritative guidance effective January 1, 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships are reported in net investment income with the earnings effect of fixed maturities, available-for-sale. Prior to 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships were reported in net realized capital gains (losses). See Note 5, Derivative Financial Instruments, for further details. Net Realized Capital Gains and Losses Major components of net realized capital gains (losses) on investments were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross gains ​ $ 134.2 ​ $ 15.5 ​ $ 40.2 ​ Gross losses ​ ​ (48.5) ​ (15.3) ​ (74.8) ​ Net credit losses (1) ​ ​ (22.9) ​ (43.5) ​ (29.1) ​ Hedging, net (2) ​ ​ (9.7) ​ (9.3) ​ (39.6) ​ Fixed maturities, trading (3) ​ ​ 3.2 ​ 43.0 ​ (9.0) ​ Equity securities (4) ​ ​ 70.5 ​ ​ 84.5 ​ ​ (17.7) ​ Mortgage loans ​ ​ (15.5) ​ 3.0 ​ 6.2 ​ Derivatives (2) ​ ​ 77.3 ​ (120.3) ​ 11.7 ​ Other ​ ​ 114.0 ​ (10.4) ​ 36.7 ​ Net realized capital gains (losses) ​ $ 302.6 ​ $ (52.8) ​ $ (75.4) ​ (1) Upon adoption of authoritative guidance effective January 1, 2020, net credit losses include adjustments to the credit loss valuation allowance, write-offs and recoveries on available-for-sale securities. Prior to 2020, net credit losses included net other-than-temporary impairment losses and recoveries on available-for-sale securities. (2) Upon adoption of authoritative guidance effective January 1, 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships are reported in net investment income with the earnings effect of fixed maturities, available-for-sale. Prior to 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships were reported in net realized capital gains (losses). See Note 5, Derivative Financial Instruments, for further details. (3) Unrealized gains (losses) on fixed maturities, trading still held at the reporting date were $5.3 million, $32.8 million and $(12.2) million for the years ended December 31, 2020, 2019 and 2018, respectively. (4) Unrealized gains (losses) on equity securities still held at the reporting date were $64.6 million, $61.6 million and $(39.9) million for the years ended December 31, 2020, 2019 and 2018, respectively. This excludes $35.2 million, $66.9 million and $ 4.9 million of unrealized gains on equity securities still held at the reporting date for the years ended December 31, 2020, 2019 and 2018, respectively, that were reported in net investment income. Proceeds from sales of investments (excluding call and maturity proceeds) in fixed maturities, available-for-sale were $2,421.9 million, $1,654.8 million and $3,067.2 million in 2020, 2019 and 2018, respectively. Allowance for Credit Loss We have a process in place to identify fixed maturity securities that could potentially require an allowance for credit loss. This process involves monitoring market events that could impact issuers’ credit ratings, business climate, management changes, litigation and government actions and other similar factors. This process also involves monitoring late payments, pricing levels, downgrades by rating agencies, key financial ratios, financial statements, revenue forecasts and cash flow projections as indicators of credit issues. Each reporting period, all securities in an unrealized loss position are reviewed to determine whether a decline in value is due to credit. Relevant facts and circumstances considered include: (1) the extent the fair value is below cost; (2) the reasons for the decline in value; (3) the financial position and access to capital of the issuer, including the current and future impact of any specific events and (4) for structured securities, the adequacy of the expected cash flows. To the extent we determine an unrealized loss is due to credit, an allowance for credit loss is recognized through a reduction to net income. ​ We estimate the amount of the allowance for credit loss as the difference between amortized cost and the present value of the expected cash flows of the security. The present value is determined using the best estimate cash flows discounted at the effective interest rate implicit to the security at the date of purchase or the current yield to accrete an asset-backed or floating rate security. The methodology and assumptions for establishing the best estimate cash flows vary depending on the type of security. The ABS cash flow estimates are based on security specific facts and circumstances that may include collateral characteristics, expectations of delinquency and default rates, loss severity and prepayment speeds and structural support, including subordination and guarantees. The corporate security cash flow estimates are derived from scenario-based outcomes of expected corporate restructurings or liquidations using bond specific facts and circumstances including timing, security interests and loss severity. We do not measure a credit loss allowance on accrued interest receivable because we write off the accrued interest receivable balance to net investment income in a timely manner when we have concern regarding collectability. Amounts on fixed maturities, available-for-sale deemed to be uncollectible are written off and removed from the allowance for credit loss. A write-off may also occur if we intend to sell a security or whether it is more likely than not we will be required to sell the security before the recovery of its amortized cost which, in some cases, may extend to maturity. A rollforward of the allowance for credit loss by major security type was as follows. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ mortgage- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ backed ​ Commercial ​ Collateralized ​ ​ ​ ​ ​ ​ ​ ​ U.S. ​ ​ ​ ​ States and ​ ​ ​ ​ pass- ​ mortgage- ​ debt ​ Other ​ ​ ​ ​ ​ government ​ Non-U.S ​ political ​ ​ ​ ​ through ​ backed ​ obligations ​ debt ​ ​ ​ ​ ​ and agencies ​ governments ​ subdivisions ​ Corporate ​ securities ​ securities ​ (2) ​ obligations ​ Total ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning balance (1) ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — Additions for credit losses not previously recorded ​ ​ — ​ ​ — ​ ​ — ​ ​ 13.2 ​ ​ — ​ ​ 2.9 ​ ​ 0.1 ​ ​ — ​ ​ 16.2 Reductions for securities sold during the period ​ ​ — ​ ​ — ​ ​ — ​ ​ (7.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (7.0) Additional increases (decreases) for credit losses on securities with an allowance recorded in the previous period ​ ​ — ​ ​ — ​ ​ — ​ ​ (5.9) ​ ​ — ​ ​ 4.0 ​ ​ 2.1 ​ ​ — ​ ​ 0.2 Write-offs charged against allowance ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2.6) ​ ​ — ​ ​ — ​ ​ (2.6) Foreign currency translation adjustment ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.6 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.6 Ending balance ​ $ — ​ $ — ​ $ — ​ $ 0.9 ​ $ — ​ $ 4.3 ​ $ 2.2 ​ $ — ​ $ 7.4 (1) The allowance for credit loss associated with fixed maturities, available-for-sale was applied prospectively upon adoption of authoritative guidance effective January 1, 2020. (2) Primarily consists of collateralized loan obligations backed by secured corporate loans. During 2020, we did not write off any accrued interest to net investment income. Other-Than-Temporary Impairments Prior to the implementation of authoritative guidance in 2020, we had a process in place to identify fixed maturity securities that could potentially have an impairment that is other than temporary. This process involved monitoring market events that could impact issuers’ credit ratings, business climate, management changes, litigation and government actions and other similar factors. This process also involved monitoring late payments, pricing levels, downgrades by rating agencies, key financial ratios, financial statements, revenue forecasts and cash flow projections as indicators of credit issues. Each reporting period, all securities were reviewed to determine whether an other-than-temporary decline in value existed and whether losses should be recognized. We considered relevant facts and circumstances in evaluating whether a credit or interest rate related impairment of a security was other than temporary. Relevant facts and circumstances considered include: (1) the extent and length of time the fair value was below cost; (2) the reasons for the decline in value; (3) the financial position and access to capital of the issuer, including the current and future impact of any specific events; (4) for structured securities, the adequacy of the expected cash flows and (5) our intent to sell a security or whether it is more likely than not we will be required to sell the security before the recovery of its amortized cost which, in some cases, may extend to maturity. To the extent we determined a security was deemed to be other than temporarily impaired, an impairment loss was recognized. The way in which impairment losses on fixed maturities were recognized in the financial statements was dependent on the facts and circumstances related to the specific security. If we intended to sell a security or it was more likely than not that we would be required to sell a security before the recovery of its amortized cost, we recognized an other-than-temporary impairment in net income for the difference between amortized cost and fair value. If we did not expect to recover the amortized cost basis, we did not plan to sell the security and if it was not more likely than not that we would be required to sell a security before the recovery of its amortized cost, the recognition of the other-than-temporary impairment was bifurcated. We recognized the credit loss portion in net income and the noncredit loss portion in OCI (“bifurcated OTTI”). Prior to 2020, net realized capital gains (losses) included total other-than-temporary impairment losses, net of recoveries from the sale of previously impaired securities, as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2019 2018 ​ ​ (in millions) Net realized capital losses, excluding impairment losses on available-for-sale securities ​ $ (9.3) ​ $ (46.3) Net other-than-temporary impairment (losses) recoveries on available-for-sale securities ​ (38.3) ​ 10.6 Other-than-temporary impairment losses on fixed maturities, available-for-sale ​ ​ ​ ​ reclassified from other comprehensive income (1) ​ ​ (5.2) ​ ​ (39.7) Net impairment losses on available-for-sale securities ​ (43.5) ​ (29.1) Net realized capital losses ​ $ (52.8) ​ $ (75.4) (1) Represents the net impact of (a) gains resulting from reclassification of noncredit impairment losses for fixed maturities with bifurcated OTTI from net realized capital gains (losses) to OCI and (b) losses resulting from reclassification of previously recognized noncredit impairment losses from OCI to net realized capital gains (losses) for fixed maturities with bifurcated OTTI that had additional credit losses or fixed maturities that previously had bifurcated OTTI that have now been sold or are intended to be sold. We estimated the amount of the credit loss component of a fixed maturity security impairment as the difference between amortized cost and the present value of the expected cash flows of the security. The present value was determined using the best estimate cash flows discounted at the effective interest rate implicit to the security at the date of purchase or the current yield to accrete an asset-backed or floating rate security. The methodology and assumptions for establishing the best estimate cash flows varied depending on the type of security. The ABS cash flow estimates were based on security specific facts and circumstances that may include collateral characteristics, expectations of delinquency and default rates, loss severity and prepayment speeds and structural support, including subordination and guarantees. The corporate security cash flow estimates were derived from scenario-based outcomes of expected corporate restructurings or liquidations using bond specific facts and circumstances including timing, security interests and loss severity. The following table provides a rollforward of accumulated credit losses for fixed maturities with bifurcated credit losses prior to the implementation of new accounting guidance in 2020. The purpose of the table is to provide detail of (1) additions to the bifurcated credit loss amounts recognized in net realized capital gains (losses) during the period and (2) decrements for previously recognized bifurcated credit losses where the loss is no longer bifurcated and/or there has been a positive change in expected cash flows or accretion of the bifurcated credit loss amount. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2019 2018 ​ ​ (in millions) ​ Beginning balance ​ $ (117.5) ​ $ (124.3) ​ Credit losses for which an other-than-temporary impairment was not previously recognized ​ (6.8) ​ (11.3) ​ Credit losses for which an other-than-temporary impairment was previously recognized ​ (11.8) ​ (20.0) ​ Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold ​ 54.3 ​ 29.5 ​ Net reduction for positive changes in cash flows expected to be collected and amortization (1) ​ 0.8 ​ 8.6 ​ Ending balance ​ $ (81.0) ​ $ (117.5) ​ (1) Amounts are recognized in net investment income. Available-for-Sale Securities in Unrealized Loss Positions Without an Allowance for Credit Loss For available-for-sale securities with unrealized losses for which an allowance for credit loss has not been recorded, the gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Less than ​ Greater than or ​ ​ ​ ​ ​ twelve months equal to twelve months ​ Total ​ ​ ​ Gross ​ ​ Gross ​ ​ Gross ​ ​ Fair ​ unrealized ​ Fair ​ unrealized ​ Fair ​ unrealized ​ value losses value losses value losses ​ ​ (in millions) Fixed maturities, available-for-sale(1): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 351.1 ​ $ 10.4 ​ $ — ​ $ — ​ $ 351.1 ​ $ 10.4 States and political subdivisions ​ 363.5 ​ 12.5 ​ — ​ — ​ 363.5 ​ 12.5 Corporate ​ 1,578.7 ​ 54.4 ​ 267.9 ​ 40.6 ​ 1,846.6 ​ 95.0 Residential mortgage-backed pass- through securities ​ 92.3 ​ 0.2 ​ 1.6 ​ — ​ 93.9 ​ 0.2 Commercial mortgage-backed securities ​ 970.9 ​ 22.1 ​ 137.4 ​ 12.2 ​ 1,108.3 ​ 34.3 Collateralized debt obligations (2) ​ 1,750.6 ​ 11.1 ​ 931.1 ​ 12.9 ​ 2,681.7 ​ 24.0 Other debt obligations ​ 802.3 ​ 28.1 ​ 61.1 ​ 1.7 ​ 863.4 ​ 29.8 Total fixed maturities, available-for-sale ​ $ 5,909.4 ​ $ 138.8 ​ $ 1,399.1 ​ $ 67.4 ​ $ 7,308.5 ​ $ 206.2 (1) Fair value and gross unrealized losses are excluded for available-for-sale securities for which an allowance for credit loss has been recorded. (2) Primarily consists of collateralized loan obligations backed by secured corporate loans. ​ Of the total amounts, Principal Life’s consolidated portfolio represented $7,029.6 million in available-for-sale fixed maturities with gross unrealized losses of $173.9 million. Of the available-for-sale fixed maturities within Principal Life's consolidated portfolio in a gross unrealized loss position, 89% were investment grade (rated AAA through BBB-) with an average price of 98 (carrying value/amortized cost) as of December 31, 2020. Gross unrealized losses in our fixed maturities portfolio increased during the year ended December 31, 2020, primarily due to widening of spreads, partially offset by a decrease in interest rates. For those securities that had been in a continuous unrealized loss position for less than twelve months, Principal Life's consolidated portfolio held 619 securities with a carrying value of $5,638.3 million and unrealized losses of $122.4 million reflecting an average price of 98 as of December 31, 2020. Of this portfolio, 89% was investment grade (rated AAA through BBB-) as of December 31, 2020, with associated unrealized losses of $98.4 million. The unrealized losses on these securities can primarily be attributed to changes in market interest rates and changes in credit spreads since the securities were acquired. For those securities that had been in a continuous unrealized loss position greater than or equal to twelve months, Principal Life's consolidated portfolio held 198 securities with a carrying value of $1,391.3 million and unrealized losses of $51.5 million as of December 31, 2020. The average credit rating of this portfolio was AA- with an average price of 96 as of December 31, 2020. Of the $51.5 million in unrealized losses, the corporate sector accounts for $24.9 million in unrealized losses with an average price of 92 and an average credit rating of BB+. The remaining unrealized losses also include $12.9 million within the collateralized debt obligation sector accounts with an average price of 99 and an average credit rating of AA+. The unrealized losses on these securities can primarily be attributed to changes in market interest rates and changes in credit spreads since the securities were acquired. Because we expected to recover our amortized cost, we did not record an allowance for credit loss on these securities as of December 31, 2020. Because it was not our intent to sell the fixed maturity available-for-sale securities with unrealized losses and it was not more likely than not that we would be required to sell these securities before recovery of the amortized cost, which may be at maturity, we did not write down these investments to fair value. Gross Unrealized Losses for Available-for-Sale Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Less than ​ Greater than or ​ ​ ​ ​ ​ ​ ​ ​ twelve months equal to twelve months ​ Total ​ ​ ​ Gross ​ Gross ​ ​ Gross ​ ​ ​ Fair ​ unrealized ​ Fair ​ unrealized ​ Fair ​ unrealized ​ ​ ​ value ​ losses (2) value losses (2) value losses (2) ​ ​ (in millions) ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 100.0 ​ $ 1.9 ​ $ 74.2 ​ $ 1.1 ​ $ 174.2 ​ $ 3.0 ​ Non-U.S. governments ​ 17.6 ​ 0.2 ​ 12.4 ​ — ​ 30.0 ​ 0.2 ​ States and political subdivisions ​ 559.9 ​ 11.2 ​ 86.3 ​ 0.4 ​ 646.2 ​ 11.6 ​ Corporate ​ 1,041.5 ​ 27.8 ​ 394.7 ​ 24.4 ​ 1,436.2 ​ 52.2 ​ Residential mortgage-backed pass- through securities ​ 429.6 ​ 1.4 ​ 237.3 ​ 2.4 ​ 666.9 ​ 3.8 ​ Commercial mortgage-backed securities ​ 829.3 ​ 9.2 ​ 268.5 ​ 14.8 ​ 1,097.8 ​ 24.0 ​ Collateralized debt obligations (1) ​ 639.4 ​ 1.8 ​ 1,447.8 ​ 12.5 ​ 2,087.2 ​ 14.3 ​ Other debt obligations ​ 1,772.8 ​ 9.5 ​ 613.7 ​ 5.4 ​ 2,386.5 ​ 14.9 ​ Total fixed maturities, available-for-sale ​ $ 5,390.1 ​ $ 63.0 ​ $ 3,134.9 ​ $ 61.0 ​ $ 8,525.0 ​ $ 124.0 ​ (1) Primarily consists of collateralized loan obligations backed by secured corporate loans. (2) Prior to the implementation of authoritative guidance in 2020, other than temporary impairment losses reported in OCI were included with gross unrealized losses resulting in total gross unrealized losses for fixed maturities, available-for-sale being reported in the table. Of the total amounts, Principal Life’s consolidated portfolio represented $8,380.7 million in available-for-sale fixed maturities with gross unrealized losses of $103.9 million. Of the available-for-sale fixed maturities within Principal Life’s consolidated portfolio in a gross unrealized loss position, 97% were investment grade (rated AAA through BBB-) with an average price of 99 (carrying value/amortized cost) as of December 31, 2019. Gross unrealized losses in our fixed maturities portfolio decreased during the year ended December 31, 2019, primarily due to a decrease in interest rates and tightening of credit spreads. For those securities that had been in a continuous unrealized loss position for less than twelve months, Principal Life’s consolidated portfolio held 882 securities with a carrying value of $5,302.7 million and unrealized losses of $44.0 million reflecting an average price of 99 as of December 31, 2019. Of this portfolio, 98% was investment grade (rated AAA through BBB-) as of December 31, 2019, with associated unrealized losses of $43.1 million. The unrealized losses on these securities can primarily be attributed to changes in market interest rates and changes in credit spreads since the securities were acquired. For those securities that had been in a continuous unrealized loss position greater than or equal to twelve months, Principal Life’s consolidated portfolio held 502 securities with a carrying value of $3,078.0 million and unrealized losses of $59.9 million. The average credit rating of this portfolio was AA+ with an average price of 98 as of December 31, 2019. Of the $59.9 million in unrealized losses, the corporate sector accounts for $23.6 million in unrealized losses with an average price of 94 and an average credit rating of BBB-. The remaining unrealized losses also include $14.6 million within the commercial mortgage-backed securities sector with an average price of 95 and an average credit rating of AA+. The unrealized losses on these securities can primarily be attributed to changes in market interest rates and changes in credit spreads since the securities were acquired. Because we expected to recover our amortized cost, it was not our intent to sell the fixed maturity available-for-sale securities with unrealized losses and it was not more likely than not that we would be required to sell these securities before recovery of the amortized cost, which may be at maturity, we did not consider these investments to be other-than-temporarily impaired as of December 31, 2019. Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments The net unrealized gains and losses on investments in available-for-sale securities and the net unrealized gains and losses on derivative instruments in cash flow hedge relationships are reported as separate components of stockholders' equity. The cumulative amount of net unrealized gains and losses on available-for-sale securities and derivative instruments in cash flow hedge relationships net of adjustments related to DAC and related actuarial balances, policyholder liabilities, noncontrolling interest and applicable income taxes was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Net unrealized gains on fixed maturities, available-for-sale (1) ​ $ 8,193.0 ​ $ 4,834.2 ​ Noncredit component of impairment losses on fixed maturities, available-for-sale (2) ​ ​ — ​ (48.4) ​ Net unrealized gains on derivative instruments ​ ​ 38.9 ​ 94.1 ​ Adjustments for assumed changes in amortization patterns ​ ​ (437.3) ​ (261.0) ​ Adjustments for assumed changes in policyholder liabilities ​ ​ (2,603.9) ​ (1,133.5) ​ Net unrealized gains on other investments and noncontrolling interest adjustments ​ ​ 78.0 ​ 96.8 ​ Provision for deferred income taxes ​ ​ (1,112.2) ​ (766.9) ​ Net unrealized gains on available-for-sale securities and derivative instruments ​ $ 4,156.5 ​ $ 2,815.3 ​ (1) Excludes net unrealized gains (losses) on fixed maturities, available-for-sale included in fair value hedging relationships. (2) Prior to the implementation of authoritative guidance in 2020, the noncredit component of impairment losses on fixed maturities, available-for-sale was included as a separate component of stockholders’ equity. Financing Receivables Mortgage Loans Mortgage loans consist of commercial and residential mortgage loans. Our commercial mortgage loan portfolio consists primarily of non-recourse, fixed rate mortgages on stabilized properties. Our residential mortgage loan portfolio is composed of first lien and home equity mortgages concentrated in Chile and the United States. Commercial and residential mortgage loans are generally reported at cost adjusted for amortization of premiums and accrual of discounts, computed using the interest method and net of valuation allowances. Amortized cost excludes accrued interest receivable. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. Interest income, as well as prepayment of fees and the amortization of the related premium or discount, is reported in net investment income on the consolidated statements of operations. Accrued interest receivable is reported in accrued investment income on the consolidated statements of financial position. Any changes in the loan valuation allowances are reported in net realized capital gains (losses) on the consolidated statements of operations. Further details relating to our valuation allowance are included under the caption “Financing Receivables Valuation Allowance.” Direct Financing Leases Our direct financing leases are concentrated in Chile. Our Chilean operations enter into private placement contracts for commercial, industrial and office space properties whereby our Chilean operations purchase the real estate and/or building from the seller-lessee but then lease the property back to the seller-lessee. Ownership of the property is transferred to the lessee by the end of the lease term. Direct financing leases are reported as a component of other investments in the consolidated statements of financial position. Reinsurance Recoverables Our reinsurance recoverables include amounts due from reinsurers for paid or unpaid claims, claims incurred but not reported or policy benefits. We cede life, disability, medical and long-term care insurance to other insurance companies through reinsurance. Reinsurance recoverables are reported with premiums due and other receivables in the consolidated statements of financial position. Credit Quality Information for Financing Receivables The amortized cost of our financing receivables by credit risk and vintage as of December 31, 2020, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 2017 2016 Prior Total ​ ​ ​ (in millions) Commercial mortgage ​ ​ ​ ​ ​ ​ ​ loans: ​ ​ ​ ​ ​ ​ ​ A- and above ​ $ 1,807.6 ​ $ 2,486.8 ​ $ 2,464.7 ​ $ 1,780.8 ​ $ 1,417.8 ​ $ 3,697.0 ​ $ 13,654.7 BBB+ thru BBB- ​ ​ 149.1 ​ ​ 194.1 ​ ​ 352.5 ​ ​ 262.7 ​ ​ 75.8 ​ ​ 499.7 ​ ​ 1,533.9 BB+ thru BB- ​ ​ 23.7 ​ ​ 69.0 ​ ​ — ​ ​ — ​ ​ 9.1 ​ ​ 43.9 ​ ​ 145.7 B+ and below ​ ​ 39.4 ​ ​ 20.0 ​ ​ — ​ ​ 5.8 ​ ​ 6.6 ​ ​ 35.5 ​ ​ 107.3 Total ​ $ 2,019.8 ​ $ 2,769.9 ​ $ 2,817.2 ​ $ 2,049.3 ​ $ 1,509.3 ​ $ 4,276.1 ​ $ 15,441.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct financing leases: ​ ​ ​ ​ ​ ​ ​ A- and above ​ $ 43.9 ​ $ 1.6 ​ $ 42.6 ​ $ 19.2 ​ $ 15.3 ​ $ 202.9 ​ $ 325.5 BBB+ thru BBB- ​ ​ 94.9 ​ ​ 5.5 ​ ​ 11.3 ​ ​ 18.4 ​ ​ 3.0 ​ ​ 35.5 ​ ​ 168.6 BB+ thru BB- ​ ​ 13.3 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 1.9 ​ ​ 15.2 B+ and below ​ ​ 57.6 ​ ​ 22.5 ​ ​ 11.9 ​ ​ — ​ ​ 1.0 ​ ​ 108.5 ​ ​ 201.5 Total ​ $ 209.7 ​ $ 29.6 ​ $ 65.8 ​ $ 37.6 ​ $ 19.3 ​ $ 348.8 ​ $ 710.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage ​ ​ ​ ​ ​ ​ ​ loans: ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 699.1 ​ $ 336.7 ​ $ 167.0 ​ $ 165.1 ​ $ 167.6 ​ $ 398.7 ​ $ 1,934.2 Non-performing ​ ​ — ​ ​ 2.0 ​ ​ 0.8 ​ ​ 1.4 ​ ​ 0.4 ​ ​ 12.7 ​ ​ 17.3 Total ​ $ 699.1 ​ $ 338.7 ​ $ 167.8 ​ $ 166.5 ​ $ 168.0 ​ $ 411.4 ​ $ 1,951.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reinsurance recoverables ​ ​ ​ ​ ​ ​ $ 1,098.0 ​ The amortized cost of commercial mortgage loans, direct financing leases and residential mortgage loans excluded accrued interest receivable of $60.0 million, $0.5 million and $2.0 million, respectively, as of December 31, 2020. The amortized cost of our commercial mortgage loan portfolio by credit risk, as determined by our internal rating system expressed in terms of an S&P bond equivalent rating, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Financial Instruments
Derivative Financial Instruments	5. Derivative Financial Instruments Derivatives are generally used to hedge or reduce exposure to market risks associated with assets held or expected to be purchased or sold and liabilities incurred or expected to be incurred. Derivatives are used to change the characteristics of our asset/liability mix consistent with our risk management activities. Derivatives are also used in asset replication strategies. Types of Derivative Instruments Interest Rate Contracts Interest rate risk is the risk we will incur economic losses due to adverse changes in interest rates. Sources of interest rate risk include the difference between the maturity and interest rate changes of assets with the liabilities they support, timing differences between the pricing of liabilities and the purchase or procurement of assets and changing cash flow profiles from original projections due to prepayment options embedded within asset and liability contracts. We use various derivatives to manage our exposure to fluctuations in interest rates. Interest rate swaps are contracts in which we agree with other parties to exchange, at specified intervals, the difference between fixed rate and/or floating rate interest amounts based upon designated market rates or rate indices and an agreed upon notional principal amount. Generally, no cash is exchanged at the outset of the contract and no principal payments are made by any party. Cash is paid or received based on the terms of the swap. We use interest rate swaps primarily to more closely match the interest rate characteristics of assets and liabilities and to mitigate the risks arising from timing mismatches between assets and liabilities (including duration mismatches). We also use interest rate swaps to hedge against changes in the value of assets we anticipate acquiring and other anticipated transactions and commitments. Interest rate swaps are used to hedge against changes in the value of the guaranteed minimum withdrawal benefit (“GMWB”) liability. The GMWB rider on our variable annuity products provides for guaranteed minimum withdrawal benefits regardless of the actual performance of various equity and/or fixed income funds available with the product. Interest rate options, including interest rate caps and interest rate floors, which can be combined to form interest rate collars, are contracts that entitle the purchaser to pay or receive the amounts, if any, by which a specified market rate exceeds a cap strike interest rate, or falls below a floor strike interest rate, respectively, at specified dates. We use interest rate options to manage prepayment risks in our assets and minimum guaranteed interest rates and lapse risks in our liabilities. A swaption is an option to enter into an interest rate swap at a future date. We purchase swaptions to hedge interest rate exposure for certain assets and liabilities. Swaptions not only hedge against the downside risk, but also allow us to take advantage of any upside benefits. In exchange-traded futures transactions, we agree to purchase or sell a specified number of contracts, the values of which are determined by the values of designated classes of securities, and to post variation margin on a daily basis in an amount equal to the difference in the daily market values of those contracts. We enter into exchange-traded futures with regulated futures commissions merchants who are members of a trading exchange. We have used exchange-traded futures to reduce market risks from changes in interest rates and to alter mismatches between the assets in a portfolio and the liabilities supported by those assets. To be announced ("TBA") forward contracts are forward settling government guaranteed mortgage-backed securities. At inception of the forward contract it is our intent to net settle rather than take physical delivery, thus the forward contracts are accounted for as derivatives. We use TBA forwards to gain exposure to the investment risk and return of agency mortgage-backed security pools in order to reduce asset and liability duration mismatch. Foreign Exchange Contracts Foreign currency risk is the risk we will incur economic losses due to adverse fluctuations in foreign currency exchange rates. This risk arises from foreign currency-denominated funding agreements issued to nonqualified institutional investors in the international market, foreign currency-denominated fixed maturity and equity securities, and our international operations, including expected cash flows and potential acquisition and divestiture activity. We use various derivatives to manage our exposure to fluctuations in foreign currency exchange rates. Currency swaps are contracts in which we agree with other parties to exchange, at specified intervals, a series of principal and interest payments in one currency for that of another currency. Generally, the principal amount of each currency is exchanged at the beginning and termination of the currency swap by each party. The interest payments are primarily fixed-to-fixed rate; however, they may also be fixed-to-floating rate or floating-to-fixed rate. These transactions are entered into pursuant to master agreements that provide for a single net payment to be made by one counterparty for payments made in the same currency at each due date. We use currency swaps to reduce market risks from changes in currency exchange rates with respect to investments or liabilities denominated in foreign currencies that we either hold or intend to acquire or sell. Currency forwards are contracts in which we agree with other parties to deliver or receive a specified amount of an identified currency at a specified future date. Typically, the price is agreed upon at the time of the contract and payment for such a contract is made at the specified future date. We use currency forwards to reduce market risks from changes in currency exchange rates with respect to investments or liabilities denominated in foreign currencies that we either hold or intend to acquire or sell. We use currency forwards to hedge certain net equity investments in foreign operations, including certain sponsored investment funds. Currency options are contracts that give the holder the right, but not the obligation to buy or sell a specified amount of the identified currency within a limited period of time at a contracted price. The contracts are net settled in cash, based on the differential in the current foreign exchange rate and the strike price. Purchased and sold options can be combined to form a foreign currency collar where we receive a payment if the foreign exchange rate is below the purchased option strike price and make a payment if the foreign exchange rate is above the sold option strike price. We have used currency options to hedge expected cash flows from our foreign operations. Equity Contracts Equity risk is the risk that we will incur economic losses due to adverse fluctuations in common stock prices. We use various derivatives to manage our exposure to equity risk, which arises from products in which the return or interest we credit is tied to an external equity index as well as products subject to minimum contractual guarantees. We purchase equity call spreads (“option collars”) to hedge the equity participation rates promised to contractholders in conjunction with our fixed deferred annuity and universal life products that credit interest based on changes in an external equity index. We use exchange-traded futures and equity put options to hedge against changes in the value of the GMWB liability related to the GMWB rider on our variable annuity product. The premium associated with certain options is paid quarterly over the life of the option contract. We also use exchange-traded futures in various fund strategies to manage an absolute return and volatility reduction objective for equity risk against respective benchmarks. Credit Contracts Credit risk relates to the uncertainty associated with the continued ability of a given obligor to make timely payments of principal and interest. We use credit default swaps to enhance the return on our investment portfolio by providing comparable exposure to fixed income securities that might not be available in the primary market. They are also used to hedge credit exposures in our investment portfolio. Credit derivatives are used to sell or buy credit protection on an identified name or names on an unfunded or synthetic basis in return for receiving or paying a quarterly premium. The premium generally corresponds to a referenced name’s credit spread at the time the agreement is executed. In cases where we sell protection, we also buy a quality cash bond to match against the credit default swap, thereby entering into a synthetic transaction replicating a cash security. When selling protection, if there is an event of default by the referenced name, as defined by the agreement, we are obligated to pay the counterparty the referenced amount of the contract and receive in return the referenced security in a principal amount equal to the notional value of the credit default swap. Other Contracts Embedded Derivatives. We offer group annuity contracts that have guaranteed separate accounts as an investment option. We also offer funds with embedded fixed-rate guarantees as investment options in our defined contribution plans in Hong Kong. We had a structured investment relationship with a trust we determined to be a VIE, which was consolidated in our financial statements. The certificates issued by the trust included obligations to deliver an underlying security to residual interest holders and the obligations contained an embedded derivative of the forecasted transaction to deliver the underlying security. The certificates matured in the second quarter of 2020. We have fixed deferred annuities and universal life products that credit interest based on changes in an external equity index. We also have certain variable annuity products with a GMWB rider, which allows the customer to make withdrawals of a specified annual amount, either for a fixed number of years or for the lifetime of the customer, even if the account value is fully exhausted. Declines in the equity markets may increase our exposure to benefits under contracts with the GMWB. We economically hedge the exposure in these contracts, as previously explained. Exposure Our risk of loss is typically limited to the fair value of our derivative instruments and not to the notional or contractual amounts of these derivatives. We are also exposed to credit losses in the event of nonperformance of the counterparties. Our current credit exposure is limited to the value of derivatives that have become favorable to us. This credit risk is minimized by purchasing such agreements from financial institutions with high credit ratings and by establishing and monitoring exposure limits. We also utilize various credit enhancements, including collateral and credit triggers to reduce the credit exposure to our derivative instruments. Derivatives may be exchange-traded or they may be privately negotiated contracts, which are usually referred to as over-the-counter (“OTC”) derivatives. Certain of our OTC derivatives are cleared and settled through central clearing counterparties (“OTC cleared”), while others are bilateral contracts between two counterparties (“bilateral OTC”). Our derivative transactions are generally documented under International Swaps and Derivatives Association, Inc. (“ISDA”) Master Agreements. Management believes that such agreements provide for legally enforceable set-off and close-out netting of exposures to specific counterparties. Under such agreements, in connection with an early termination of a transaction, we are permitted to set off our receivable from a counterparty against our payables to the same counterparty arising out of all included transactions. For reporting purposes, we do not offset fair value amounts of bilateral OTC derivatives for the right to reclaim cash collateral or the obligation to return cash collateral against fair value amounts recognized for derivative instruments executed with the same counterparties under master netting agreements. OTC cleared derivatives have variation margin that is legally characterized as settlement of the derivative exposure, which reduces their fair value in the consolidated statements of financial position. We posted $148.3 million and $271.6 million in cash and securities under collateral arrangements as of December 31, 2020 and December 31, 2019, respectively, to satisfy collateral and initial margin requirements associated with our derivative credit support agreements and FCM agreements. Certain of our derivative instruments contain provisions that require us to maintain an investment grade rating from each of the major credit rating agencies on our debt. If the ratings on our debt were to fall below investment grade, it would be in violation of these provisions and the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing full overnight collateralization on derivative instruments in net liability positions. The aggregate fair value, inclusive of accrued interest, of all derivative instruments with credit-risk-related contingent features that were in a liability position without regard to netting under derivative credit support annex agreements as of December 31, 2020 and December 31, 2019, was $180.2 million and $164.7 million, respectively. Cleared derivatives have contingent features that require us to post excess margin as required by the FCM. The terms surrounding excess margin vary by FCM agreement. With respect to derivatives containing collateral triggers, we posted collateral and initial margin of $148.3 million and $271.6 million as of December 31, 2020 and December 31, 2019, respectively, in the normal course of business, which reflects netting under derivative agreements. If the credit-risk-related contingent features underlying these agreements were triggered on December 31, 2020, we would be required to post an additional $44.4 million of collateral to our counterparties. As of December 31, 2020 and December 31, 2019, we had received $225.2 million and $156.8 million, respectively, of cash collateral associated with our derivative credit support annex agreements and FCM agreements, for which we recorded a corresponding liability reflecting our obligation to return the collateral. Notional amounts are used to express the extent of our involvement in derivative transactions and represent a standard measurement of the volume of our derivative activity. Notional amounts represent those amounts used to calculate contractual flows to be exchanged and are not paid or received, except for contracts such as currency swaps. Credit exposure represents the gross amount owed to us under derivative contracts as of the valuation date. The notional amounts and credit exposure of our derivative financial instruments by type were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ ​ (in millions) ​ Notional amounts of derivative instruments ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Interest rate swaps ​ $ 44,472.1 ​ $ 35,173.6 ​ Interest rate options ​ ​ 2,083.9 ​ 1,416.9 ​ Interest rate forwards ​ ​ 1,000.0 ​ ​ — ​ Interest rate futures ​ ​ 188.5 ​ 142.5 ​ Swaptions ​ ​ 62.0 ​ 62.0 ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ Currency forwards ​ ​ 1,115.8 ​ 1,182.3 ​ Currency swaps ​ ​ 1,045.5 ​ 1,027.2 ​ Currency options ​ ​ — ​ ​ 53.8 ​ Equity contracts: ​ ​ ​ ​ ​ ​ ​ Equity options ​ ​ 1,857.8 ​ 1,672.8 ​ Equity futures ​ ​ 218.1 ​ 149.5 ​ Credit contracts: ​ ​ ​ ​ ​ ​ ​ Credit default swaps ​ ​ 295.0 ​ 165.0 ​ Other contracts: ​ ​ ​ ​ ​ ​ ​ Embedded derivatives ​ ​ 9,953.8 ​ 9,742.3 ​ Total notional amounts at end of period ​ $ 62,292.5 ​ $ 50,787.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit exposure of derivative instruments ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Interest rate swaps ​ $ 291.0 ​ $ 181.9 ​ Interest rate options ​ ​ 51.0 ​ 28.3 ​ Interest rate forwards ​ ​ 6.2 ​ ​ — ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ Currency swaps ​ ​ 43.3 ​ 55.4 ​ Currency forwards ​ ​ 45.4 ​ 4.9 ​ Currency options ​ ​ — ​ ​ 0.1 ​ Equity contracts: ​ ​ ​ ​ ​ ​ ​ Equity options ​ ​ 33.2 ​ 30.5 ​ Credit contracts: ​ ​ ​ ​ ​ ​ ​ Credit default swaps ​ ​ 3.4 ​ 0.5 ​ Total gross credit exposure ​ ​ 473.5 ​ 301.6 ​ Less: collateral received ​ ​ 294.7 ​ 208.3 ​ Net credit exposure ​ $ 178.8 ​ $ 93.3 ​ ​ ​ The fair value of our derivative instruments classified as assets and liabilities was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative assets (1) ​ Derivative liabilities (2) ​ ​ December 31, 2020 December 31, 2019 December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Derivatives designated as hedging instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ $ — ​ $ — ​ $ 27.8 ​ $ 21.3 ​ Foreign exchange contracts ​ ​ 21.1 ​ 30.0 ​ ​ 44.7 ​ 15.2 ​ Total derivatives designated as hedging instruments ​ $ 21.1 ​ $ 30.0 ​ $ 72.5 ​ $ 36.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ $ 339.3 ​ $ 204.2 ​ $ 33.0 ​ $ 16.7 ​ Foreign exchange contracts ​ ​ 66.5 ​ 29.5 ​ ​ 29.2 ​ 100.2 ​ Equity contracts ​ ​ 33.2 ​ 30.5 ​ ​ 49.0 ​ 63.1 ​ Credit contracts ​ ​ 3.4 ​ 0.5 ​ ​ 2.5 ​ 1.2 ​ Other contracts ​ ​ — ​ — ​ ​ 467.8 ​ 312.8 ​ Total derivatives not designated as hedging instruments ​ ​ 442.4 ​ 264.7 ​ ​ 581.5 ​ 494.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total derivative instruments ​ $ 463.5 ​ $ 294.7 ​ $ 654.0 ​ $ 530.5 ​ (1) The fair value of derivative assets is reported with other investments on the consolidated statements of financial position. (2) The fair value of derivative liabilities is reported with other liabilities on the consolidated statements of financial position, with the exception of certain embedded derivative liabilities. Embedded derivatives with a net liability fair value of $467.8 million and $214.2 million as of December 31, 2020 and December 31, 2019, respectively, are reported with contractholder funds on the consolidated statements of financial position. Credit Derivatives Sold When we sell credit protection, we are exposed to the underlying credit risk similar to purchasing a fixed maturity security instrument. Our credit derivative contracts sold reference a single name or reference security (referred to as “single name credit default swaps”). These instruments are either referenced in an OTC credit derivative transaction or embedded within an investment structure that has been fully consolidated into our financial statements. These credit derivative transactions are subject to events of default defined within the terms of the contract, which normally consist of bankruptcy, failure to pay, or modified restructuring of the reference entity and/or issue. If a default event occurs for a reference name or security, we are obligated to pay the counterparty an amount equal to the notional amount of the credit derivative transaction. As a result, our maximum future payment is equal to the notional amount of the credit derivative. In certain cases, we also may have purchased credit protection with identical underlyings to certain of our sold protection transactions. As of December 31, 2020 and December 31, 2019, we did not purchase credit protection relating to our sold protection transactions. In certain circumstances, our potential loss could also be reduced by any amount recovered in the default proceedings of the underlying credit name. ​ The following tables show our credit default swap protection sold by types of contract, types of referenced/underlying asset class and external agency rating for the underlying reference security. The maximum future payments are undiscounted and have not been reduced by the effect of any offsetting transactions, collateral or recourse features described above. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ Maximum ​ average ​ ​ ​ Notional ​ Fair ​ future ​ expected life ​ ​ amount value payments (in years) ​ ​ ​ (in millions) ​ Single name credit default swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A ​ $ 20.0 ​ $ 0.5 ​ $ 20.0 4.5 ​ BBB ​ 115.0 ​ 2.1 ​ 115.0 3.9 ​ Sovereign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A ​ ​ 20.0 ​ ​ 0.6 ​ ​ 20.0 ​ 4.5 ​ BBB ​ ​ 15.0 ​ ​ 0.1 ​ ​ 15.0 ​ 1.0 ​ Total credit default swap protection sold ​ $ 170.0 ​ $ 3.3 ​ $ 170.0 3.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ Maximum ​ average ​ ​ ​ Notional ​ Fair ​ future ​ expected life ​ ​ amount value payments (in years) ​ ​ ​ (in millions) ​ Single name credit default swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt ​ ​ ​ ​ ​ ​ ​ ​ ​ A ​ $ 5.0 ​ $ — ​ $ 5.0 0.5 ​ BBB ​ 70.0 ​ 0.2 ​ 70.0 2.6 ​ Sovereign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ BBB ​ ​ 15.0 ​ ​ 0.3 ​ ​ 15.0 ​ 2.0 ​ Total credit default swap protection sold ​ $ 90.0 ​ $ 0.5 ​ $ 90.0 2.4 ​ ​ Fair Value and Cash Flow Hedges Fair Value Hedges We use fixed-to-floating rate interest rate swaps to more closely align the interest rate characteristics of certain assets and have used them to align the interest rate characteristics of certain liabilities. In general, these swaps are used in asset and liability management to modify duration, which is a measure of sensitivity to interest rate changes. The net interest effect of interest rate swap transactions for derivatives in fair value hedges is recorded as an adjustment to income or expense of the underlying hedged item in our consolidated statements of operations. The following amounts were recorded on the consolidated statements of financial position related to cumulative basis adjustments for fair value hedges. The amortized cost includes the amortized cost basis and the fair value hedging basis adjustment. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative amount of fair ​ ​ ​ ​ ​ ​ ​ ​ ​ value hedging basis adjustment ​ Line item in the consolidated statements ​ ​ ​ ​ ​ ​ ​ included in the amortized cost ​ of financial position in which the ​ Amortized cost of hedged item ​ of the hedged item ​ hedged item is included December 31, 2020 December 31, 2019 December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Active hedging relationships ​ $ 476.1 ​ $ 142.0 ​ $ 21.4 ​ $ 18.1 ​ Discontinued hedging relationships ​ ​ 135.1 ​ ​ 159.3 ​ ​ 5.2 ​ ​ 7.7 ​ Total fixed maturities, available-for-sale in active or discontinued hedging relationships ​ $ 611.2 ​ $ 301.3 ​ $ 26.6 ​ $ 25.8 ​ ​ Cash Flow Hedges We utilized floating-to-fixed rate interest rate swaps to eliminate the variability in cash flows of recognized financial assets and liabilities and forecasted transactions. We enter into currency exchange swap agreements to convert both principal and interest payments of certain foreign denominated assets and liabilities into U.S. dollar denominated fixed-rate instruments to eliminate the exposure to future currency volatility on those items. The net interest effect of interest rate swap and currency swap transactions for derivatives in cash flow hedges is recorded as an adjustment to income or expense of the underlying hedged item in our consolidated statements of operations. The following table shows the effect of derivatives in cash flow hedging relationships on the consolidated statements of financial position. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in AOCI on derivatives ​ Derivatives in cash flow ​ ​ ​ for the year ended December 31, ​ hedging relationships Related hedged item 2020 2019 2018 ​ ​ ​ ​ (in millions) ​ Interest rate contracts ​ Fixed maturities, available-for-sale ​ $ (3.0) ​ $ (9.9) ​ $ 36.7 ​ Foreign exchange contracts ​ Fixed maturities, available-for-sale ​ ​ (37.1) ​ (9.4) ​ 20.8 ​ Foreign exchange contracts ​ Investment contracts ​ ​ — ​ — ​ (0.1) ​ Total ​ ​ ​ $ (40.1) ​ $ (19.3) ​ $ 57.4 ​ ​ We expect to reclassify net gains of $23.5 million from AOCI into net income in the next 12 months, which includes both net deferred gains on discontinued hedges and net gains on periodic settlements of active hedges. Actual amounts may vary from this amount as a result of market conditions. ​ Effect of Fair Value and Cash Flow Hedges on Consolidated Statements of Operations The following tables show the effect of derivatives in fair value and cash flow hedging relationships and the related hedged items on the consolidated statements of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ Benefits, ​ ​ ​ ​ ​ Net investment ​ Net realized ​ claims and ​ ​ ​ ​ ​ income related ​ capital gains ​ settlement ​ ​ ​ ​ ​ to hedges ​ related to ​ expenses ​ ​ ​ ​ ​ of fixed ​ hedges of fixed ​ related to ​ Operating ​ ​ maturities, ​ maturities, ​ hedges of ​ expenses ​ ​ available- ​ available- ​ investment ​ related to ​ for-sale for-sale contracts hedges of debt ​ ​ (in millions) Total amounts of consolidated statement of operations line items in which the effects of fair value and cash flow hedges are reported ​ $ 3,890.6 ​ $ 302.6 ​ $ 8,281.5 ​ $ 4,646.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses on fair value hedging relationships: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain recognized on hedged item ​ $ 3.3 ​ $ — ​ $ — ​ $ — ​ Loss recognized on derivatives ​ (3.8) ​ — ​ — ​ — ​ Amortization of hedged item basis adjustments ​ (2.5) ​ — ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ (6.2) ​ — ​ — ​ — ​ Total loss recognized for fair value hedging relationships ​ $ (9.2) ​ $ — ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gains (losses) on cash flow hedging relationships: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (loss) reclassified from AOCI on derivatives ​ $ 18.1 ​ $ 2.7 ​ $ (0.1) ​ $ — ​ Gain reclassified from AOCI as a result that a forecasted transaction is no longer probable of occurring ​ — ​ 0.1 ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain reclassified from AOCI on derivatives ​ — ​ 6.3 ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ 8.2 ​ — ​ — ​ — ​ Total gain (loss) recognized for cash flow hedging relationships ​ $ 26.3 ​ $ 9.1 ​ $ (0.1) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Benefits, ​ ​ ​ ​ ​ Net investment ​ Net realized ​ claims and ​ ​ ​ ​ ​ income related ​ capital gains ​ settlement ​ ​ ​ ​ ​ to hedges ​ (losses) related to ​ expenses ​ ​ ​ ​ ​ of fixed ​ hedges of fixed ​ related to ​ Operating ​ ​ maturities, ​ maturities, ​ hedges of ​ expenses ​ ​ available- ​ available- ​ investment ​ related to ​ for-sale for-sale contracts hedges of debt ​ ​ (in millions) Total amounts of consolidated statement of operations line items in which the effects of fair value and cash flow hedges are reported ​ $ 3,998.4 ​ $ (52.8) ​ $ 9,905.8 ​ $ 4,503.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses on fair value hedging relationships: ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Gain recognized on hedged item ​ $ 5.7 ​ $ — ​ $ — ​ $ — ​ Loss recognized on derivatives ​ (6.0) ​ — ​ — ​ — ​ Amortization of hedged item basis adjustments ​ (4.2) ​ — ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ (3.4) ​ — ​ — ​ — ​ Total loss recognized for fair value hedging relationships ​ $ (7.9) ​ $ — ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gains (losses) on cash flow hedging relationships: ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Gain (loss) reclassified from AOCI on derivatives ​ $ 19.8 ​ $ (0.6) ​ $ (0.1) ​ $ (4.8) ​ Gain reclassified from AOCI as a result that a forecasted transaction is no longer probable of occurring ​ — ​ 0.1 ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ Gain reclassified from AOCI on derivatives ​ — ​ 9.5 ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ 7.4 ​ — ​ — ​ — ​ Total gain (loss) recognized for cash flow hedging relationships ​ $ 27.2 ​ $ 9.0 ​ $ (0.1) ​ $ (4.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ Net ​ Net realized ​ ​ ​ ​ ​ ​ ​ ​ investment ​ capital ​ Benefits, ​ ​ ​ ​ ​ income ​ gains (losses) ​ claims and ​ ​ ​ ​ ​ related ​ related to ​ settlement ​ ​ ​ ​ ​ to hedges ​ hedges ​ expenses ​ Operating ​ ​ of fixed ​ of fixed ​ related to ​ expenses ​ ​ maturities, ​ maturities, ​ hedges of ​ related to ​ ​ available- ​ available- ​ investment ​ hedges ​ for-sale for-sale contracts of debt ​ ​ (in millions) Total amounts of consolidated statement of operations line items in which the effects of fair value and cash flow hedges are reported ​ $ 3,629.2 ​ $ (75.4) ​ $ 8,192.5 ​ $ 4,136.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses on fair value hedging relationships: ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ Loss recognized on hedged item ​ $ — ​ $ (6.6) ​ $ — ​ $ — ​ Gain recognized on derivatives ​ — ​ 6.2 ​ — ​ — ​ Amortization of hedged item basis adjustments ​ (6.7) ​ — ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ (5.9) ​ — ​ — ​ — ​ Total loss recognized for fair value hedging relationships ​ $ (12.6) ​ $ (0.4) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gains (losses) on cash flow hedging relationships: ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ Gain (loss) reclassified from AOCI on derivatives ​ $ 20.9 ​ $ 17.0 ​ $ (0.1) ​ $ (10.7) ​ Gain reclassified from AOCI as a result that a forecasted transaction is no longer probable of occurring ​ — ​ 0.3 ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange contracts: ​ ​ ​ ​ ​ Gain reclassified from AOCI on derivatives ​ — ​ 12.7 ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ 6.0 ​ — ​ (0.1) ​ — ​ Total gain (loss) recognized for cash flow hedging relationships ​ $ 26.9 ​ $ 30.0 ​ $ (0.2) ​ $ (10.7) ​ ​ Net Investment Hedges We may take measures to hedge our net equity investments in our foreign operations from currency risk. This is accomplished with the use of currency forwards. Gains and losses associated with net investment hedges are recorded in AOCI and will be released into net income if our investment in the foreign operation is sold or substantially liquidated. The following table shows the effect of foreign exchange contracts used to hedge a portion of our net investment in certain sponsored investment funds on the consolidated financial statements. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain recognized ​ ​ in AOCI on derivatives for the year ended ​ ​ December 31, Derivatives in net investment hedging relationships 2020 2019 2018 ​ ​ (in millions) Foreign exchange contracts ​ $ 7.9 ​ $ — ​ $ — Total ​ $ 7.9 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain reclassified from AOCI into ​ ​ net realized capital gains (losses) ​ ​ for the year ended December 31, Derivatives in net investment hedging relationships 2020 2019 2018 ​ ​ (in millions) Foreign exchange contracts ​ $ (7.1) ​ $ — ​ $ — Total ​ $ (7.1) ​ $ — ​ $ — ​ ​ ​ Derivatives Not Designated as Hedging Instruments Our use of futures, certain swaptions and swaps, option collars, options and forwards are effective from an economic standpoint, but they have not been designated as hedges for financial reporting purposes. As such, periodic changes in the market value of these instruments, which includes mark-to-market gains and losses as well as periodic and final settlements, primarily flow directly into net realized capital gains (losses) on the consolidated statements of operations. The following table shows the effect of derivatives not designated as hedging instruments, including fair value changes of embedded derivatives that have been bifurcated from the host contract, on the consolidated statements of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in ​ ​ ​ net income on derivatives for the ​ ​ ​ year ended December 31, ​ Derivatives not designated as hedging instruments 2020 2019 2018 ​ ​ (in millions) ​ Interest rate contracts ​ $ 346.5 ​ $ 218.0 ​ $ (27.6) ​ Foreign exchange contracts ​ ​ 54.7 ​ (58.6) ​ (64.2) ​ Equity contracts ​ ​ (96.6) ​ (132.9) ​ (31.0) ​ Credit contracts ​ ​ 1.8 ​ (3.6) ​ (1.6) ​ Other contracts ​ ​ (255.5) ​ (168.1) ​ 108.5 ​ Total ​ $ 50.9 ​ $ (145.2) ​ $ (15.9) ​ ​

Closed Block

Closed Block	12 Months Ended
	Dec. 31, 2020
Closed Block
Closed Block	6. Closed Block In connection with the 1998 MIHC formation, Principal Life formed a Closed Block to provide reasonable assurance to policyholders included therein that, after the formation of the MIHC, assets would be available to maintain dividends in aggregate in accordance with the 1997 policy dividend scales, if the experience underlying such scales continued. Assets of Principal Life were allocated to the Closed Block in an amount that produces cash flows which, together with anticipated revenue from policies and contracts included in the Closed Block, were expected to be sufficient to support the Closed Block policies. This includes, but is not limited to, provisions for payment of claims, certain expenses, charges and taxes, and to provide for continuation of policy and contract dividends in aggregate in accordance with the 1997 dividend scales, if the experience underlying such scales continues, and to allow for appropriate adjustments in such scales, if such experience changes. Due to adjustable life policies being included in the Closed Block, the Closed Block is charged with amounts necessary to properly fund for certain adjustments, such as face amount and premium increases, that are made to these policies after the Closed Block inception date. These amounts are referred to as Funding Adjustment Charges and are treated as capital transfers from the Closed Block. Assets allocated to the Closed Block inure solely to the benefit of the holders of policies included in the Closed Block. Closed Block assets and liabilities are carried on the same basis as other similar assets and liabilities. Principal Life will continue to pay guaranteed benefits under all policies, including the policies within the Closed Block, in accordance with their terms. If the assets allocated to the Closed Block, the investment cash flows from those assets and the revenues from the policies included in the Closed Block, including investment income thereon, prove to be insufficient to pay the benefits guaranteed under the policies included in the Closed Block, Principal Life will be required to make such payments from its general funds. No additional policies were added to the Closed Block, nor was the Closed Block affected in any other way, as a result of the demutualization. A policyholder dividend obligation (“PDO”) is required to be established for higher than expected earnings in the Closed Block that will need to be paid as dividends unless future performance of the Closed Block is less favorable than originally expected. A model of the Closed Block was established to produce the pattern of expected earnings, assets and liabilities in the Closed Block. These projections are utilized to determine ratios that will allow us to compare actual cumulative earnings to expected cumulative earnings and determine the amount of the PDO. As of December 31, 2020 and 2019, the PDO was $298.2 million and $202.7 million, respectively. Closed Block liabilities and assets designated to the Closed Block were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) Closed Block liabilities ​ ​ ​ ​ ​ ​ ​ Future policy benefits and claims ​ $ 3,423.2 ​ $ 3,563.1 ​ Other policyholder funds ​ ​ 6.0 ​ 6.6 ​ Policyholder dividends payable ​ ​ 189.0 ​ 199.1 ​ Policyholder dividends obligation ​ ​ 298.2 ​ 202.7 ​ Other liabilities ​ ​ 8.7 ​ 7.8 ​ Total Closed Block liabilities ​ ​ 3,925.1 ​ 3,979.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets designated to the Closed Block ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ ​ 2,353.3 ​ 2,269.6 ​ Fixed maturities, trading ​ ​ 2.6 ​ 2.6 ​ Equity securities ​ ​ 1.1 ​ 1.1 ​ Mortgage loans ​ ​ 565.9 ​ 622.8 ​ Policy loans ​ ​ 456.8 ​ 486.0 ​ Other investments ​ ​ 61.7 ​ 46.4 ​ Total investments ​ ​ 3,441.4 ​ 3,428.5 ​ Cash and cash equivalents ​ ​ 23.2 ​ 47.5 ​ Accrued investment income ​ ​ 35.4 ​ 38.1 ​ Premiums due and other receivables ​ ​ 8.3 ​ 9.7 ​ Deferred tax asset ​ ​ 24.2 ​ 29.5 ​ Total assets designated to the Closed Block ​ ​ 3,532.5 ​ 3,553.3 ​ Excess of Closed Block liabilities over assets designated to the Closed Block ​ ​ 392.6 ​ 426.0 ​ Amounts included in accumulated other comprehensive income ​ ​ 0.9 ​ 0.9 ​ Maximum future earnings to be recognized from Closed Block assets and liabilities ​ $ 393.5 ​ $ 426.9 ​ ​ Closed Block revenues and expenses were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ 217.6 ​ $ 227.6 ​ $ 244.2 ​ Net investment income ​ ​ 143.6 ​ 154.4 ​ 160.5 ​ Net realized capital gains (losses) ​ ​ 16.0 ​ 7.4 ​ (3.4) ​ Total revenues ​ ​ 377.2 ​ 389.4 ​ 401.3 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ ​ 212.8 ​ 204.4 ​ 211.5 ​ Dividends to policyholders ​ ​ 117.8 ​ 116.3 ​ 120.9 ​ Operating expenses ​ ​ 2.7 ​ 2.9 ​ 3.3 ​ Total expenses ​ ​ 333.3 ​ 323.6 ​ 335.7 ​ Closed Block revenues, net of Closed Block expenses, before income taxes ​ ​ 43.9 ​ 65.8 ​ 65.6 ​ Income taxes ​ ​ 8.4 ​ 12.9 ​ 11.1 ​ Closed Block revenues, net of Closed Block expenses and income taxes ​ ​ 35.5 ​ 52.9 ​ 54.5 ​ Funding adjustments ​ ​ (2.2) ​ (3.0) ​ (0.5) ​ Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustments ​ $ 33.3 ​ $ 49.9 ​ $ 54.0 ​ ​ ​ The change in maximum future earnings of the Closed Block was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Beginning of year ​ $ 426.9 ​ $ 476.8 ​ $ 532.1 ​ Effects of implementation of accounting changes (1) ​ ​ 0.1 ​ ​ — ​ ​ 1.3 ​ End of year ​ ​ 393.5 ​ 426.9 ​ 476.8 ​ Change in maximum future earnings ​ $ (33.3) ​ $ (49.9) ​ $ (54.0) ​ (1) Includes the effects of implementation of accounting changes related to credit losses in 2020 and equity investments and the reclassification of certain tax effects in 2018. Principal Life charges the Closed Block with U.S. federal income taxes, payroll taxes, state and local premium taxes and other state or local taxes, licenses and fees as provided in the plan of reorganization.

Deferred Acquisition Costs

Deferred Acquisition Costs	12 Months Ended
	Dec. 31, 2020
Deferred Acquisition Costs
Deferred Acquisition Costs	7. Deferred Acquisition Costs Acquisition costs deferred and amortized were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Balance at beginning of year ​ $ 3,521.3 ​ $ 3,693.5 ​ $ 3,540.7 ​ Costs deferred during the year ​ ​ 457.0 ​ 473.5 ​ 414.9 ​ Amortized to expense during the year (1) ​ ​ (388.1) ​ (347.0) ​ (253.5) ​ Adjustment related to unrealized (gains) losses on available-for-sale securities and derivative instruments ​ ​ (180.5) ​ (298.7) ​ 184.9 ​ Other (2) ​ ​ — ​ ​ — ​ ​ (193.5) ​ Balance at end of year ​ $ 3,409.7 ​ $ 3,521.3 ​ $ 3,693.5 ​ (1) Includes adjustments for revisions to EGPs. (2) Reflects the impact of capitalized costs written off or transferred from DAC to a contract cost asset as a result of adopting revenue recognition guidance in 2018. See Note 1, Nature of Operations and Significant Accounting Policies, under the caption “Recent Accounting Pronouncements” for further details .

Insurance Liabilities

Insurance Liabilities	12 Months Ended
	Dec. 31, 2020
Insurance Liabilities
Insurance Liabilities	8. Insurance Liabilities Contractholder Funds Major components of contractholder funds in the consolidated statements of financial position were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Liabilities for investment contracts: ​ ​ ​ ​ ​ ​ ​ Liabilities for individual annuities ​ $ 12,864.1 ​ $ 13,457.5 ​ GICs ​ ​ 11,858.0 ​ 10,423.5 ​ Funding agreements ​ ​ 9,407.3 ​ 8,640.6 ​ Other investment contracts ​ ​ 1,762.4 ​ 1,596.7 ​ Total liabilities for investment contracts ​ ​ 35,891.8 ​ 34,118.3 ​ Universal life and other reserves ​ ​ 7,345.9 ​ 7,249.2 ​ Total contractholder funds ​ $ 43,237.7 ​ $ 41,367.5 ​ ​ ​ Our GICs and funding agreements contain provisions limiting or prohibiting early surrenders, which typically include penalties for early surrenders, minimum notice requirements or, in the case of funding agreements with survivor options, minimum pre-death holding periods and specific maximum amounts. Funding agreements include those issued directly to nonqualified institutional investors and those issued to the FHLB Des Moines under their membership funding programs. As of December 31, 2020 and 2019, $4,252.5 million and $4,010.9 million, respectively, of liabilities were outstanding with respect to issuances under the program with FHLB Des Moines. In addition, we have five separate programs where the funding agreements have been issued directly or indirectly to unconsolidated special purpose entities. Claims for principal and interest under funding agreements are afforded equal priority to claims of life insurance and annuity policyholders under insolvency provisions of Iowa Insurance Laws. Principal Life was authorized to issue up to $4.0 billion of funding agreements under a program established in 1998 to support the prospective issuance of medium term notes by an unaffiliated entity in non-U.S. markets. As of December 31, 2020 and 2019, $75.0 million and $75.2 million, respectively, of liabilities were outstanding with respect to the issuance outstanding under this program. Principal Life was also authorized to issue up to Euro 4.0 billion (approximately USD$5.3 billion) of funding agreements under a program established in 2006 to support the prospective issuance of medium term notes by an unaffiliated entity in non-U.S. markets. The unaffiliated entity is an unconsolidated special purpose entity. As of December 31, 2020 and 2019, $122.4 million and $112.2 million, respectively, of liabilities were outstanding with respect to issuances outstanding under this program. Principal Life does not anticipate any new issuance activity under either of these programs due to the existence of the program established in 2011 described below. In addition, Principal Life was authorized to issue up to $7.0 billion of funding agreements under a program established in 2001 to support the prospective issuance of medium term notes by an unaffiliated entity in both domestic and international markets. The unaffiliated entity is an unconsolidated special purpose entity. As of December 31, 2020 and 2019, $201.8 million and $201.7 million, respectively, of liabilities were being held with respect to issuances outstanding under this program. Principal Life does not anticipate any new issuance activity under this program, given our December 2005 termination of the dealership agreement for this program and the availability of the program established in 2011 described below. Additionally, Principal Life was authorized to issue up to $9.0 billion of funding agreements under a program that was originally established in March 2004 to support the prospective issuance of medium term notes by unaffiliated entities in both domestic and international markets. Under this program, both the notes and the supporting funding agreements were registered with the United States Securities and Exchange Commission (“SEC”). As of April 2020, there were no outstanding funding agreements or medium term notes associated with this program. As of December 31, 2019, $26.2 million of liabilities were being held with respect to issuances outstanding under this program. In contrast with direct funding agreements, GIC issuances and the other three funding agreement-backed medium term note programs described above, Principal Life's payment obligations on each funding agreement issued under this SEC-registered program were guaranteed by PFG. Principal Life does not anticipate any new issuance activity under this program due to the existence of the program established in 2011 described below. Principal Life was authorized to issue up to $5.0 billion of funding agreements under a program that was originally established in 2011 to support the prospective issuance of medium term notes by an unaffiliated entity in both domestic and international markets. The unaffiliated entity is an unconsolidated special purpose entity. In June 2015, this program was amended to authorize issuance of up to an additional $4.0 billion in recognition of the use of nearly all $5.0 billion of existing issuance authorization. In November 2017, this program was amended to authorize issuance of up to an additional $4.0 billion. As of December 31, 2020 and 2019, $4,755.8 million and $4,214.3 million, respectively, of liabilities were being held with respect to issuances outstanding under this program. Principal Life’s payment obligations on each funding agreement issued under this program are guaranteed by PFG. The program established in 2011 is not registered with the SEC. ​ Liability for Unpaid Claims The liability for unpaid claims is reported in future policy benefits and claims within our consolidated statements of financial position. Activity associated with unpaid claims was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Balance at beginning of year ​ $ 2,365.5 ​ $ 2,252.7 ​ $ 2,130.5 ​ Less: reinsurance recoverable ​ ​ 403.8 ​ ​ 404.3 ​ ​ 375.8 ​ Net balance at beginning of year ​ ​ 1,961.7 ​ ​ 1,848.4 ​ ​ 1,754.7 ​ Incurred: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current year ​ ​ 1,376.8 ​ 1,361.3 ​ 1,268.8 ​ Prior years ​ ​ 26.6 ​ 0.8 ​ 0.3 ​ Total incurred ​ ​ 1,403.4 ​ 1,362.1 ​ 1,269.1 ​ Payments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current year ​ ​ 863.8 ​ 869.4 ​ 815.7 ​ Prior years ​ ​ 403.3 ​ 379.4 ​ 359.7 ​ Total payments ​ ​ 1,267.1 ​ 1,248.8 ​ 1,175.4 ​ Net balance at end of year ​ ​ 2,098.0 ​ ​ 1,961.7 ​ ​ 1,848.4 ​ Plus: reinsurance recoverable ​ ​ 436.9 ​ ​ 403.8 ​ ​ 404.3 ​ Balance at end of year ​ $ 2,534.9 ​ $ 2,365.5 ​ $ 2,252.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts not included in the rollforward above: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claim adjustment expense liabilities ​ $ 57.8 ​ $ 57.9 ​ $ 54.6 ​ ​ Incurred liability adjustments relating to prior years, which affected current operations during 2020, 2019 and 2018, resulted in part from developed claims for prior years being different than were anticipated when the liabilities for unpaid claims were originally estimated. These trends have been considered in establishing the current year liability for unpaid claims. Short-Duration Contracts Claims Development The following tables present undiscounted information about claims development by incurral year, including separate information about incurred claims and paid claims net of reinsurance for the periods indicated. The tables also include information on incurred but not reported claims and the cumulative number of reported claims. The tables present information for the number of years for which claims incurred typically remain outstanding, but do not exceed ten years. The data is disaggregated into groupings of claims with similar characteristics, such as duration of the claim payment period and average claim amount, and with consideration to the overall size of the groupings. Outstanding liabilities equal total net incurred claims less total net paid claims plus outstanding liabilities for net unpaid claims of prior years. ​ LTD and Group Life Waiver Claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Incurred ​ ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ but not ​ ​ number of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ reported ​ ​ reported ​ ​ ​ Net incurred claims (1) ​ claims ​ ​ claims ​ ​ ​ December 31, ​ ​ 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2020 2020 ​ ​ ​ ($ in millions) ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2011 ​ $ 203.7 ​ $ 192.6 ​ $ 185.4 ​ $ 184.8 ​ $ 178.4 ​ $ 172.3 ​ $ 169.6 ​ $ 167.6 ​ $ 166.5 ​ $ 167.0 ​ $ 0.1 ​ ​ 6,294 ​ 2012 ​ ​ ​ ​ ​ 217.9 ​ ​ 200.0 ​ ​ 191.1 ​ ​ 189.5 ​ ​ 181.8 ​ ​ 174.8 ​ ​ 173.3 ​ ​ 171.9 ​ ​ 173.1 ​ ​ 0.1 ​ ​ 6,445 ​ 2013 ​ ​ ​ ​ ​ ​ ​ ​ 219.3 ​ ​ 203.3 ​ ​ 188.4 ​ ​ 190.7 ​ ​ 182.3 ​ ​ 179.5 ​ ​ 177.1 ​ ​ 173.4 ​ ​ 0.1 ​ ​ 7,050 ​ 2014 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 242.2 ​ ​ 231.4 ​ ​ 214.4 ​ ​ 218.1 ​ ​ 206.2 ​ ​ 201.9 ​ ​ 202.0 ​ ​ 0.1 ​ ​ 7,603 ​ 2015 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 231.0 ​ ​ 227.2 ​ ​ 217.2 ​ ​ 215.3 ​ ​ 208.2 ​ ​ 210.0 ​ ​ 0.1 ​ ​ 7,179 ​ 2016 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 229.8 ​ ​ 228.4 ​ ​ 219.4 ​ ​ 219.5 ​ ​ 214.4 ​ ​ 0.1 ​ ​ 6,163 ​ 2017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 238.4 ​ ​ 239.7 ​ ​ 243.1 ​ ​ 245.8 ​ ​ 4.4 ​ ​ 6,074 ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 239.4 ​ ​ 245.1 ​ ​ 239.2 ​ ​ 6.6 ​ ​ 5,738 ​ 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 255.2 ​ ​ 248.4 ​ ​ 3.2 ​ ​ 5,858 ​ 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 252.1 ​ ​ 87.0 ​ ​ 3,588 ​ Total net incurred claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,125.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cumulative paid claims (1) ​ ​ December 31, ​ 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 ​ ​ (in millions) Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2011 ​ $ 11.2 ​ $ 50.0 ​ $ 72.5 ​ $ 85.7 ​ $ 95.4 ​ $ 105.2 ​ $ 112.6 ​ $ 119.3 ​ $ 125.4 ​ $ 129.7 2012 ​ ​ ​ ​ ​ 13.8 ​ ​ 55.1 ​ ​ 80.8 ​ ​ 93.7 ​ ​ 104.6 ​ ​ 112.9 ​ ​ 120.0 ​ ​ 126.1 ​ ​ 131.5 2013 ​ ​ ​ ​ ​ ​ ​ ​ 12.5 ​ ​ 55.0 ​ ​ 81.4 ​ ​ 97.0 ​ ​ 106.4 ​ ​ 116.4 ​ ​ 123.2 ​ ​ 129.0 2014 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 16.1 ​ ​ 66.0 ​ ​ 96.3 ​ ​ 111.8 ​ ​ 122.3 ​ ​ 132.4 ​ ​ 140.8 2015 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 16.9 ​ ​ 67.0 ​ ​ 98.0 ​ ​ 114.6 ​ ​ 126.8 ​ ​ 137.1 2016 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 16.2 ​ ​ 70.6 ​ ​ 105.6 ​ ​ 124.9 ​ ​ 136.8 2017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 17.8 ​ ​ 76.5 ​ ​ 115.0 ​ ​ 135.9 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 20.1 ​ ​ 79.9 ​ ​ 115.7 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 19.2 ​ ​ 79.7 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 20.6 Total net paid claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 1,156.8 All outstanding liabilities for unpaid claims prior to 2011 net of reinsurance ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 240.2 Total outstanding liabilities for unpaid claims net of reinsurance ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,208.8 (1) 2011-2019 unaudited. ​ Dental, Vision, STD, Critical Illness and Accident Claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Incurred ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ but not ​ number of ​ ​ ​ ​ ​ reported ​ reported ​ ​ ​ Net incurred claims (1) ​ claims ​ claims ​ ​ ​ December 31, ​ ​ 2019 2020 2020 2020 ​ ​ ($ in millions) ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 724.7 ​ $ 711.6 ​ $ — ​ ​ 3,363,947 ​ 2020 ​ ​ ​ ​ ​ 679.8 ​ ​ 45.0 ​ ​ 2,899,957 ​ Total net incurred claims ​ ​ ​ ​ $ 1,391.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ paid claims (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2020 ​ ​ ​ ​ ​ ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 653.5 ​ $ 711.5 ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ ​ ​ 609.5 ​ ​ ​ ​ ​ ​ ​ Total net paid claims ​ ​ ​ ​ ​ 1,321.0 ​ ​ ​ ​ ​ ​ ​ All outstanding liabilities for unpaid claims prior to 2019 net of reinsurance ​ ​ ​ ​ ​ — ​ ​ ​ ​ ​ ​ ​ Total outstanding liabilities for unpaid claims net of reinsurance ​ ​ ​ ​ $ 70.4 ​ ​ ​ ​ ​ ​ ​ (1) 2019 unaudited. ​ Group Life Claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Incurred ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ but not ​ number of ​ ​ ​ ​ ​ reported ​ reported ​ ​ ​ Net incurred claims (1) ​ claims ​ claims ​ ​ ​ December 31, ​ ​ 2019 2020 2020 2020 ​ ​ ($ in millions) ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 228.3 ​ $ 224.6 ​ $ 0.7 ​ ​ 5,117 ​ 2020 ​ ​ ​ ​ ​ 270.6 ​ ​ 21.9 ​ ​ 5,505 ​ Total net incurred claims ​ ​ ​ ​ $ 495.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ paid claims (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ ​ ​ ​ 2019 2020 ​ ​ ​ ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 181.7 ​ $ 223.0 ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ ​ ​ 219.3 ​ ​ ​ ​ ​ ​ ​ Total net paid claims ​ ​ ​ ​ ​ 442.3 ​ ​ ​ ​ ​ ​ ​ All outstanding liabilities for unpaid claims prior to 2019 net of reinsurance ​ ​ ​ ​ ​ 1.1 ​ ​ ​ ​ ​ ​ ​ Total outstanding liabilities for unpaid claims net of reinsurance ​ ​ ​ ​ $ 54.0 ​ ​ ​ ​ ​ ​ ​ (1) 2019 unaudited. Reconciliation of Unpaid Claims to Liability for Unpaid Claims Our reconciliation of net outstanding liabilities for unpaid claims of short-duration contracts to the liability for unpaid claims follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ Dental, Vision, STD, ​ ​ ​ ​ ​ ​ ​ ​ ​ LTD and Group Life ​ Critical Illness and ​ ​ ​ ​ ​ ​ ​ ​ Waiver Accident Group Life Consolidated ​ ​ (in millions) ​ Net outstanding liabilities for unpaid claims ​ $ 1,208.8 ​ $ 70.4 ​ $ 54.0 ​ $ 1,333.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reconciling items: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reinsurance recoverable on unpaid claims ​ ​ 53.3 ​ ​ — ​ ​ 0.1 ​ ​ 53.4 ​ Impact of discounting ​ ​ (214.5) ​ ​ — ​ ​ — ​ ​ (214.5) ​ Liability for unpaid claims - short-duration contracts ​ $ 1,047.6 ​ $ 70.4 ​ $ 54.1 ​ ​ 1,172.1 ​ Insurance contracts other than short-duration ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 1,362.8 ​ Liability for unpaid claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,534.9 ​ ​ ​ Claim Duration and Payout Our historical average percentage of claims paid in each year from incurral was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 (1) ​ ​ ​ ​ ​ Dental, Vision, STD, ​ ​ ​ ​ ​ LTD and Group Life ​ Critical Illness and ​ Group ​ Year Waiver Accident Life ​ 1 ​ 7.7 % 91.7 % 81.5 % 2 ​ 24.3 ​ 8.0 ​ 17.3 ​ 3 ​ 15.1 ​ ​ ​ ​ ​ 4 ​ 8.2 ​ ​ ​ ​ ​ 5 ​ 5.7 ​ ​ ​ ​ ​ 6 ​ 5.2 ​ ​ ​ ​ ​ 7 ​ 4.2 ​ ​ ​ ​ ​ 8 ​ 3.6 ​ ​ ​ ​ ​ 9 ​ 3.4 ​ ​ ​ ​ ​ 10 ​ 2.6 ​ ​ ​ ​ ​ (1) Unaudited. Discounting The following table provides the carrying amount of liabilities reported at present value for short-duration contract unpaid claims. We use a range of discount rates to derive the present value of the unpaid claims. The ranges of discount rates as well as the aggregate amount of discount deducted to derive the liabilities for unpaid claims and interest accretion recognized are also disclosed. Interest accretion is included in benefits, claims and settlement expenses within our consolidated statements of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dental, Vision, STD, ​ ​ ​ ​ ​ ​ ​ LTD and Group Life ​ Critical Illness and ​ ​ ​ ​ ​ ​ Waiver ​ Accident ​ Group Life ​ ​ ​ ($ in millions) ​ Carrying amount of liabilities for unpaid claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ $ ​ ​ 1,047.6 ​ $ ​ ​ 70.4 ​ ​ $ ​ ​ 54.1 ​ December 31, 2019 ​ ​ ​ ​ 1,029.9 ​ ​ ​ ​ 71.2 ​ ​ ​ ​ ​ 50.4 ​ Range of discount rates ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ 2.8 - 7.0 % ​ — - — % ​ ​ — - — % December 31, 2019 ​ ​ 3.3 - 7.0 ​ ​ — - — ​ ​ ​ — - — ​ Aggregate amount of discount ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ $ ​ ​ 214.5 ​ $ ​ ​ — ​ ​ $ ​ ​ — ​ December 31, 2019 ​ ​ ​ ​ 215.0 ​ ​ ​ ​ — ​ ​ ​ ​ ​ — ​ Interest accretion ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ $ ​ ​ 33.9 ​ $ ​ ​ — ​ ​ $ ​ ​ — ​ December 31, 2019 ​ ​ ​ ​ 34.2 ​ ​ ​ ​ — ​ ​ ​ ​ ​ — ​ December 31, 2018 ​ ​ ​ ​ 34.5 ​ ​ ​ ​ — ​ ​ ​ ​ ​ — ​ ​

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt
Debt	9. Debt Short-Term Debt The components of short-term debt were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Financing ​ ​ ​ ​ ​ ​ Short-term debt Obligor/Applicant structure Maturity Capacity outstanding ​ ​ ​ ​ ​ ​ (in millions) PFG, Principal Financial Services, Inc. ("PFS") and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life as co-borrowers Credit facility November 2023 ​ $ 600.0 ​ $ — PFG, PFS, Principal Life and Principal Financial ​ ​ ​ Services V (UK) LTD as co-borrowers Credit facility November 2023 ​ 200.0 ​ — Principal International Chile (1) Unsecured lines of credit ​ 186.6 ​ 84.7 Total ​ $ 986.6 ​ $ 84.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Financing ​ ​ ​ ​ ​ ​ Short-term debt Obligor/Applicant structure Maturity Capacity outstanding ​ ​ ​ ​ ​ ​ (in millions) PFG, PFS and Principal Life as co-borrowers Credit facility November 2023 ​ $ 600.0 ​ $ — PFG, PFS, Principal Life and Principal Financial ​ ​ Services V (UK) LTD as co-borrowers Credit facility November 2023 ​ 200.0 ​ — Principal International Chile (1) Unsecured lines of credit ​ ​ ​ 134.5 ​ 93.4 Principal Life Unsecured line of credit ​ September 2020 ​ 60.0 ​ — Total ​ ​ ​ ​ ​ $ 994.5 ​ $ 93.4 (1) The unsecured lines of credit can be used for repurchase agreements or other borrowings. Each line has a maturity of less than one year . Our revolving credit facilities are committed and available for general corporate purposes. These credit facilities also provide 100% back-stop support for our commercial paper program, of which we had no outstanding balances as of December 31, 2020 and 2019. The weighted-average interest rate on short-term borrowings as of both December 31, 2020 and 2019, was 3.4%. Long-Term Debt The components of long-term debt were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Principal Net unamortized Carrying ​ ​ (in millions) 3.3% notes payable, due 2022 ​ $ 300.0 ​ $ (0.7) ​ $ 299.3 ​ 3.125% notes payable, due 2023 ​ ​ 300.0 ​ ​ (0.7) ​ 299.3 ​ 3.4% notes payable, due 2025 ​ ​ 400.0 ​ ​ (2.2) ​ 397.8 ​ 3.1% notes payable, due 2026 ​ ​ 350.0 ​ ​ (2.1) ​ ​ 347.9 ​ 3.7% notes payable, due 2029 ​ ​ 500.0 ​ ​ (5.5) ​ ​ 494.5 ​ 2.125% notes payable, due 2030 ​ ​ 600.0 ​ ​ (4.6) ​ ​ 595.4 ​ 6.05% notes payable, due 2036 ​ ​ 505.6 ​ ​ (2.5) ​ 503.1 ​ 4.625% notes payable, due 2042 ​ ​ 300.0 ​ ​ (3.1) ​ 296.9 ​ 4.35% notes payable, due 2043 ​ ​ 300.0 ​ ​ (3.1) ​ 296.9 ​ 4.3% notes payable, due 2046 ​ ​ 300.0 ​ ​ (3.2) ​ ​ 296.8 ​ Floating rate notes payable, due 2055 ​ ​ 400.0 ​ ​ (4.7) ​ 395.3 ​ Non-recourse mortgages and notes payable ​ 55.5 ​ 0.5 ​ 56.0 ​ Total long-term debt ​ $ 4,311.1 ​ $ (31.9) ​ $ 4,279.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Principal Net unamortized Carrying ​ ​ (in millions) ​ 3.3% notes payable, due 2022 ​ $ 300.0 ​ $ (1.0) ​ $ 299.0 ​ 3.125% notes payable, due 2023 ​ ​ 300.0 ​ ​ (1.0) ​ ​ 299.0 ​ 3.4% notes payable, due 2025 ​ ​ 400.0 ​ ​ (2.6) ​ 397.4 ​ 3.1% notes payable, due 2026 ​ ​ 350.0 ​ ​ (2.5) ​ ​ 347.5 ​ 3.7% notes payable, due 2029 ​ ​ 500.0 ​ ​ (6.1) ​ ​ 493.9 ​ 6.05% notes payable, due 2036 ​ ​ 505.6 ​ ​ (2.4) ​ 503.2 ​ 4.625% notes payable, due 2042 ​ ​ 300.0 ​ ​ (3.2) ​ 296.8 ​ 4.35% notes payable, due 2043 ​ ​ 300.0 ​ ​ (3.3) ​ ​ 296.7 ​ 4.3% notes payable, due 2046 ​ ​ 300.0 ​ ​ (3.3) ​ ​ 296.7 ​ 4.7% notes payable, due 2055 ​ ​ 400.0 ​ ​ (4.9) ​ 395.1 ​ Non-recourse mortgages and notes payable ​ ​ 107.6 ​ ​ 1.2 ​ 108.8 ​ Total long-term debt ​ $ 3,763.2 ​ $ (29.1) ​ $ 3,734.1 ​ ​ Net discount, premium and issuance costs associated with issuing these notes are amortized to expense over the respective terms using the interest method. On June 12, 2020, we issued $500.0 million of senior notes at a discount. On August 3, 2020, we issued an additional $100.0 million of senior notes at a premium. These notes bear interest at 2.125% and will mature in 2030. Interest on the notes is payable semi-annually on June 15 and December 15 each year, beginning on December 15, 2020. The proceeds from these notes were used for general corporate purposes. On May 7, 2019, we issued $500.0 million of senior notes. The notes bear interest at 3.7% and will mature in 2029. Interest on the notes is payable semi-annually on May 15 and November 15 each year, beginning on November 15, 2019. The proceeds from these notes, along with available cash, were used to fund the acquisition of the Acquired Business. On November 10, 2016, we issued $650.0 million of senior notes. We issued a $350.0 million series of notes that bear interest at 3.1% and will mature in 2026 and a $300.0 million series of notes that bear interest at 4.3% and will mature in 2046. Interest on the notes is payable semi-annually on May 15 and November 15 each year, beginning on May 15, 2017. The proceeds from these notes were used to redeem our notes payable due in 2017 and 2019. We incurred a one-time cost to extinguish this debt before the scheduled maturity date. On May 7, 2015, we issued $400.0 million of senior notes. The notes bear interest at 3.4% and will mature in 2025. Interest on the notes is payable semi-annually on May 15 and November 15 each year, beginning on November 15, 2015. In addition, on May 7, 2015, we issued $400.0 million of junior subordinated notes, which are subordinated to all our senior debt. The notes became callable in 2020 and have a maturity date in 2055. The notes initially bore a fixed rate of interest at 4.7% and converted to a floating rate at the date the notes became callable. Interest on the notes is payable semi-annually on May 15 and November 15 each year. After the call date the notes bear interest at 3-month LIBOR plus 3.044%, reset quarterly and payable in arrears in February, May, August and November each year. We have the right to defer interest payments on the junior subordinated notes for up to 5 years without resulting in a default, during which time interest will be compounded. The proceeds from these notes were used to redeem preferred stock, with the remainder available for general corporate purposes. On November 16, 2012, we issued $900.0 million of senior notes. We issued a $300.0 million series of notes that bore interest at 1.85% and were to mature in 2017. These notes were repaid following our November 2016 debt issuance. We issued a $300.0 million series of notes that bear interest at 3.125% and will mature in 2023 and a $300.0 million series of notes that bear interest at 4.35% and will mature in 2043. Interest on the notes is payable semi-annually on May 15 and November 15 each year, beginning on May 15, 2013. The proceeds were used to fund our acquisition of Cuprum. On September 5, 2012, we issued $600.0 million of senior notes. We issued a $300.0 million series of notes that bear interest at 3.3% and will mature in 2022 and a $300.0 million series of notes that bear interest at 4.625% and will mature in 2042. Interest on the notes is payable semi-annually on March 15 and September 15 each year, beginning on March 15, 2013. The proceeds were used for the repayment of the $400.0 million aggregate principal amount of notes due in 2014 and to partially fund our acquisition of Cuprum. On May 18, 2009, we issued $750.0 million of senior notes. We issued a $400.0 million series of notes that bore interest at 7.875% and were to mature on May 15, 2014. These notes were repaid following our November 2012 debt issuance. We issued a $350.0 million series of notes that bore interest at 8.875% and were to mature on May 15, 2019. These notes were repaid following our November 2016 debt issuance. Interest on the notes was payable semi-annually on May 15 and November 15 each year, beginning on November 15, 2009. The proceeds were primarily used to refinance $440.9 million of notes that matured on August 15, 2009, with the remaining proceeds being used for general corporate purposes. On October 16 and December 5, 2006, we issued $500.0 million and $100.0 million, respectively, of senior notes. The notes bear interest at a rate of 6.05% per year. Interest on the notes is payable semi-annually on April 15 The non-recourse mortgages and notes payable are primarily financings for real estate developments. Outstanding principal balances as of December 31, 2020, ranged from $3.1 million to $15.1 million per development with interest rates ranging from 3.5% to 4.8%. Outstanding principal balances as of December 31, 2019, ranged from $3.7 million to $64.2 million per development with interest rates ranging from 3.9% to 4.8%. Outstanding debt is secured by the underlying real estate properties, which were reported as real estate on our consolidated statements of financial position with a carrying value of $194.1 million and $238.2 million as of December 31, 2020 and 2019, respectively. As of December 31, 2020, future annual maturities of long-term debt were as follows (in millions): ​ ​ ​ ​ ​ ​ Year ending December 31: ​ 2021 ​ $ 2.0 ​ 2022 ​ ​ 301.4 ​ 2023 ​ ​ 323.8 ​ 2024 ​ ​ 17.5 ​ 2025 ​ ​ 398.2 ​ Thereafter ​ ​ 3,236.3 ​ Total future maturities of long-term debt ​ $ 4,279.2 ​ ​ Contingent Funding Agreements for Senior Debt Issuance On March 8, 2018, we entered into two contingent funding agreements: (1) a 10-year contingent funding agreement with a Delaware trust (“2028 Trust”) formed by us in connection with the sale by the trust of $400.0 million pre-capitalized trust securities redeemable February 15, 2028 ("2028 P-Caps") in a Rule 144A private placement and (2) a 30-year contingent funding agreement with a Delaware trust (“2048 Trust”) formed by us in connection with the sale by the trust of $350.0 million pre-capitalized trust securities redeemable February 15, 2048 ("2048 P-Caps") in a Rule 144A private placement. The trusts invested the proceeds from the sale of the 2028 P-Caps and 2048 P-Caps in a portfolio of principal and interest strips of U.S. Treasury securities. The contingent funding agreements provide us a put option that gives us the right to sell at any time: (1) to the 2028 Trust up to $400.0 million of its 4.111% Senior Notes due 2028 ("4.111% Senior Notes") and (2) to the 2048 Trust up to $350.0 million of its 4.682% Senior Notes due 2048 (“4.682% Senior Notes”) and receive in exchange a corresponding amount of the principal and interest strips of U.S. Treasury securities held by the trusts. The 4.111% Senior Notes and 4.682% Senior Notes will not be issued unless and until a put option is exercised. We agreed to pay a semi-annual put premium of 1.275% and 1.580% per annum on the unexercised portion of the put option to the 2028 Trust and 2048 Trust, respectively, and to reimburse the trusts for expenses. The put option premiums are recorded in operating expenses in the consolidated statements of operations. The 4.111% Senior Notes and 4.682% Senior Notes will be fully, irrevocably and unconditionally guaranteed by PFS. In addition, our obligations under the put option agreement and the expense reimbursement agreement with the trusts are also guaranteed by PFS. The contingent funding agreements with the trusts provide us with a source of liquid assets, which could be used to meet future financial obligations or to provide additional capital. The put options described above will be exercised automatically in full if we fail to make certain payments to the trusts, including any failure to pay the put option premium or expense reimbursements when due, if such failure is not cured within 30 days, and upon certain bankruptcy events involving us or PFS. We are also required to exercise the put option in full: (i) if we reasonably believe that our consolidated shareholders’ equity, calculated in accordance with U.S. GAAP but excluding AOCI and noncontrolling interest, has fallen below $4.0 billion, subject to adjustment in certain cases; (ii) upon the occurrence of an event of default under the 4.111% Senior Notes and 4.682% Senior Notes; and (iii) if certain events occur relating to each trust’s status as an "investment company" under the Investment Company Act of 1940. In addition, we are required to purchase from the trusts any principal and interest strips of U.S. Treasury securities that are due and not paid. We have an unlimited right to unwind a prior voluntary exercise of the put options by repurchasing all of the 4.111% Senior Notes and 4.682% Senior Notes held by the trusts in exchange for a corresponding amount of principal and interest strips of U.S. Treasury securities. If the put options have been fully exercised, the 4.111% Senior Notes and 4.682% Senior Notes issued may be redeemed by us prior to their maturity at par or, if greater, at a make-whole redemption price, in each case plus accrued and unpaid interest to the date of redemption. The 2028 P-Caps are to be redeemed by the 2028 Trust on February 15, 2028, or upon any early redemption of the 4.111% Senior Notes. The 2048 P-Caps are to be redeemed by the 2048 Trust on February 15, 2048, or upon any early redemption of the 4.682% Senior Notes.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Taxes
Income Taxes	10. Income Taxes Income Taxes (Benefits) Our income taxes (benefit) were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Current income taxes (benefits): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ $ 15.8 ​ $ 31.9 ​ $ (48.9) ​ State ​ ​ 5.0 ​ 18.1 ​ 10.3 ​ Foreign ​ ​ 55.4 ​ 45.6 ​ 51.7 ​ Tax benefit of operating loss carryforward ​ ​ (3.3) ​ (3.0) ​ (13.5) ​ Total current income taxes (benefits) ​ ​ 72.9 ​ 92.6 ​ (0.4) ​ Deferred income taxes (benefits): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ ​ 143.6 ​ 108.6 ​ 224.3 ​ State ​ ​ 11.5 ​ 6.9 ​ 19.2 ​ Foreign ​ ​ 37.0 ​ 41.1 ​ (12.4) ​ Total deferred income taxes ​ ​ 192.1 ​ 156.6 ​ 231.1 ​ Income taxes ​ $ 265.0 ​ $ 249.2 ​ $ 230.7 ​ ​ Our income before income taxes was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Domestic $ 1,323.2 $ 1,351.9 $ 1,661.1 ​ Foreign ​ ​ 370.3 ​ ​ 341.4 ​ ​ 123.3 ​ Total income before income taxes $ 1,693.5 $ 1,693.3 $ 1,784.4 ​ ​ Effective Income Tax Rate Our provision for income taxes may not have the customary relationship of taxes to income. A reconciliation between the U.S. corporate income tax rate and the effective income tax rate was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 U.S. corporate income tax rate 21 % 21 % 21 % Dividends received deduction ​ (4) ​ (5) ​ (4) ​ Tax credits ​ (3) ​ (3) ​ (3) ​ Impact of equity method presentation ​ (1) ​ (2) ​ (1) ​ Interest exclusion from taxable income ​ (1) ​ — ​ (1) ​ Impact of the Tax Cuts and Jobs Act ​ — ​ — ​ (3) ​ State income taxes ​ 1 ​ 1 ​ 1 ​ Local country permanent tax adjustments ​ — ​ 1 ​ 1 ​ Other ​ 3 ​ 2 ​ 2 ​ Effective income tax rate ​ 16 % 15 % 13 % ​ ​ Unrecognized Tax Benefits Our changes in unrecognized tax benefits were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Balance at beginning of period ​ $ 61.6 ​ $ 42.1 ​ $ 194.1 ​ Additions based on tax positions related to the current year ​ ​ 1.3 ​ 0.1 ​ 0.8 ​ Additions for tax positions of prior years ​ ​ 17.4 ​ 23.1 ​ 43.7 ​ Reductions for tax positions related to the current year ​ ​ (3.2) ​ (3.2) ​ (10.6) ​ Reductions for tax positions of prior years ​ ​ — ​ (0.5) ​ (23.2) ​ Settlements ​ ​ (14.5) ​ ​ — ​ ​ (162.7) ​ Expired statute of limitations ​ ​ (15.7) ​ ​ — ​ ​ — ​ Balance at end of period (1) ​ $ 46.9 ​ $ 61.6 ​ $ 42.1 ​ (1) If recognized, $1.1 million of the above amount of unrecognized tax benefits would reduce our 2020 effective income tax rate. We recognize interest and penalties related to uncertain tax positions in operating expenses within the consolidated statements of operations. As of December 31, 2020, 2019 and 2018, we had recognized $1.1 million, $0.9 million and $1.6 million of accumulated pre-tax interest and penalties related to unrecognized tax benefits, respectively. We do not believe there is a reasonable possibility the total amount of the unrecognized tax benefits will significantly increase or decrease in the next twelve months considering recent settlements and the status of current and pending Internal Revenue Service (“IRS”) examinations. Settlement agreements applicable to tax years 1995 to 2003 were executed in 2018 with the Department of Justice, as previously approved by the Joint Committee of Taxation in August 2017. In 2019, an IRS 30-day letter on examination of tax years 2009 through 2012 was received, the proposed adjustments found acceptable, and associated tax settlements subsequently occurred in 2020, within the period of the extended statute of limitation. The IRS continued examination of tax years 2015 through 2017 and initiated examination of tax year 2018. Net Deferred Income Taxes Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Our significant components of net deferred income taxes were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Deferred income tax assets: ​ ​ ​ ​ ​ ​ ​ Investments, including derivatives ​ $ 588.4 ​ $ 237.0 ​ Insurance liabilities ​ ​ 552.4 ​ 143.2 ​ Net operating and capital loss carryforwards ​ ​ 69.2 ​ 71.1 ​ Tax credit carryforwards ​ ​ 4.6 ​ ​ 106.0 ​ Employee benefits ​ ​ 389.1 ​ 338.9 ​ Foreign currency translation ​ ​ 9.7 ​ ​ 14.0 ​ Other deferred income tax assets ​ ​ 52.5 ​ 45.2 ​ Gross deferred income tax assets ​ ​ 1,665.9 ​ 955.4 ​ Valuation allowance ​ ​ (18.4) ​ (16.7) ​ Total deferred income tax assets ​ ​ 1,647.5 ​ 938.7 ​ Deferred income tax liabilities: ​ ​ ​ ​ ​ ​ ​ Deferred acquisition costs ​ ​ (522.6) ​ (562.9) ​ Investments, including derivatives ​ ​ (990.4) ​ (443.7) ​ Net unrealized gains on available-for-sale securities ​ ​ (1,762.1) ​ (1,039.9) ​ Real estate ​ ​ (158.5) ​ (147.9) ​ Intangible assets ​ ​ (387.5) ​ (342.3) ​ Other deferred income tax liabilities ​ ​ (43.4) ​ (75.0) ​ Total deferred income tax liabilities ​ ​ (3,864.5) ​ (2,611.7) ​ Total net deferred income tax liabilities ​ $ (2,217.0) ​ $ (1,673.0) ​ ​ Our net deferred income taxes by jurisdiction were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Deferred income tax assets: ​ ​ ​ ​ ​ ​ ​ State ​ $ 81.1 ​ $ 94.9 ​ Foreign ​ ​ 32.7 ​ ​ 28.7 ​ Net deferred income tax assets ​ ​ 113.8 ​ 123.6 ​ Deferred income tax liabilities: ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ ​ (2,011.8) ​ (1,507.6) ​ Foreign ​ ​ (319.0) ​ (289.0) ​ Net deferred income tax liabilities ​ ​ (2,330.8) ​ (1,796.6) ​ Total net deferred income tax liabilities ​ $ (2,217.0) ​ $ (1,673.0) ​ ​ In management’s judgment, total deferred income tax assets are more likely than not to be realized. Included in the deferred income tax asset are tax carryforwards available to offset future taxable income or income taxes. As of December 31, 2020 and 2019, we had tax credit carryforwards for U.S. federal income tax purposes of $4.6 million and $106.0 million, respectively. Alternative minimum, foreign and general business tax credit carryovers were generated during and since the period we utilized net operating losses, primarily attributable to our captive reinsurance companies that joined our consolidated U.S. federal income tax return beginning in 2012 and 2013. The AMT credit carryforwards became refundable in 2018 and were fully recovered in 2018, and the foreign tax credit carryforwards were fully utilized in 2020. The general business credit carryforward will expire by 2040 if unused. As of December 31, 2020, all accumulated U.S. federal tax credit carryforwards are anticipated to be utilized before expiration; therefore, no valuation allowance has been provided for the related deferred income tax assets. As of December 31, 2020 and 2019, domestic state net operating loss carryforwards were $269.5 million and $190.4 million, respectively, and will expire between 2032 and 2039. As of December 31, 2020 and 2019, foreign net operating loss carryforwards were $170.3 million and $186.1 million, respectively, with some expiring in 2020 while others never expire. We maintain valuation allowances by jurisdiction against the deferred income tax assets related to some of these carryforwards and other items, as utilization of these income tax benefits fail the more likely than not criteria in certain jurisdictions. As of December 31, 2020 and 2019, valuation allowances of $18.4 million and $16.7 million, respectively, had been recorded against the income tax benefits associated primarily with foreign net operating loss carryforwards. Adjustments to the valuation allowance will be made if there is a change in management’s assessment of the amount of the deferred income tax assets that are more likely than not to be realized. Provisions of the U.S. tax reform did not affect the valuation allowance assessment. The effects of tax legislation on deferred taxes are recognized in the period of enactment. The State of Iowa coupled with the Internal Revenue Code effective January 1, 2019, and subsequently issued interpretative guidance in the fourth quarter of 2019 on application of the U.S. Global Intangible Low Taxed Income rules. The State of Iowa's interpretation resulted in an $11.1 million increase in total income tax expense for adjustments to deferred tax assets and liabilities in our 2019 financial statements. Iowa legislation was enacted on June 29, 2020 to de-couple from the federal application of the U.S. Global Intangible Low Taxed Income rules effective retroactively to January 1, 2019; therefore, the above-mentioned increase in total income tax expense reported in 2019 was reversed in 2020. Proposed regulations issued August 1, 2018, clarifying the calculation of the one-time deemed repatriation tax, allowed for final determination of the 2017 provisional amount. The impact of final §965 regulations issued on January 15, 2019, and subsequent clarification was immaterial. The provisional amount of $43.0 million reported in 2017 was adjusted by $5.9 million in 2018 to $48.9 million to reflect the SEC's Staff Accounting Bulletin No. 118 final determination within the required one-year measurement period. Deferred tax liabilities are recognized for taxes payable on the unremitted earnings from foreign operations of our subsidiaries, except where it is our intention to indefinitely reinvest a portion or all of these undistributed earnings. As of December 31, 2020 and 2019, any applicable taxes that would be due upon repatriation were not provided on approximately $997.4 million and $1,001.5 million, respectively, of such accumulated but undistributed earnings from operations of foreign subsidiaries. We currently do not intend to repatriate these unremitted earnings because we have several liquidity options to fund our domestic operations and obligations. These options include investing and financing activities, such as issuing debt, as well as cash flow and dividends from domestic operations. As of December 31, 2020 and 2019, it was not practicable to determine the amount of the unrecognized deferred tax liability that would arise if foreign earnings were remitted, due to the complexity of our international holding company structure, and other significant tax attributes and varying state tax laws. Under the participation exemption available on distributions post-U.S. tax reform, taxes on remittances would be limited to foreign currency gains or losses, foreign withholding taxes, and state income taxes, which we would anticipate to be immaterial. As of December 31, 2020, deferred taxes were also not provided on the approximately $106.2 million of excess book carrying value over tax basis with respect to the original investment in our foreign subsidiaries. A tax liability will be recognized when we no longer plan to indefinitely reinvest a portion or all of these earnings or when we plan to sell a portion or all of our ownership interest. Other Tax Information Income tax returns are filed in U.S. federal jurisdiction as well as various states and foreign jurisdictions where we and one or more of our subsidiaries conduct business. Although determined by jurisdiction, with few exceptions our tax uncertainties relate primarily to the U.S. federal jurisdiction. The IRS has completed examination of our consolidated U.S. federal income tax returns for years prior to 2015. A settlement was reached in 2018 with the Department of Justice involving a suit in the Court of Federal Claims, requesting refunds for the years 1995-2003. IRS claims for refund for tax years 2004 through 2008, following settlement of a partnership matter with the Department of Justice in March 2019, were finalized in 2020 following review by the Joint Committee of Taxation. As of December 31, 2020 and 2019, we had $54.6 million and $195.3 million, respectively, of current income tax receivables associated with outstanding audit issues reported as other assets in our consolidated statements of financial position. Refund claims filed for tax years 2006 through 2008 in 2015 were received in September 2020. The IRS commenced audit of our U.S. federal income tax return for 2009 in 2011, 2010 in 2012, 2011 in 2013, 2012 in 2015, 2015 through 2017 in 2019 and 2018 in the fourth quarter of 2020. The U.S. federal statute of limitations expired for years prior to 2009, except for pending audit issues. The statute was extended until June 30, 2021, for 2009 through 2012 although effectively settled, has expired for 2013 and 2014, and was extended for tax years 2015 and 2016 through October 15, 2021. The statute remains open for tax years 2017 and 2018 through October 15, 2021 and 2022, respectively. The ultimate settlement of earlier tax years can be adjusted into subsequent tax years regardless of statute status. We do not expect the results of these audits, subsequent related adjustments or developments in other tax areas for all open tax years to significantly change the possible increase in the amount of unrecognized tax benefits, but the outcome of tax reviews is uncertain and unforeseen results can occur. We believe we have adequate defenses against, or sufficient provisions for, contested issues, but final resolution could take several years depending on whether legal remedies are pursued. Consequently, we do not believe issues that might arise in tax years subsequent to 2014 will have a material impact on our net income.

Employee and Agent Benefits

Employee and Agent Benefits	12 Months Ended
	Dec. 31, 2020
Employee and Agent Benefits
Employee and Agent Benefits	11. Employee and Agent Benefits We provide a U.S. qualified defined benefit pension plan, covering U.S. employees that meet certain eligibility requirements and certain agents contracted on or before December 31, 2018. A final average pay benefit formula has been in place for plan participants employed prior to January 1, 2002. For agents, this formula ended on December 31, 2018, and for employees the formula will end on December 31, 2022. The final average pay benefit is based on the years of service and generally the employee's or agent's average annual compensation during the last five years prior to the earliest of termination, retirement or the formula end date. A cash balance benefit was added on January 1, 2002. A participant's cash balance account is credited with an amount based on the participant’s salary, age and service. These credits accrue with interest. For plan participants hired on and after January 1, 2002, only the cash balance benefit applies. For pre-2002 participants, the pension benefit earned prior to the final average pay formula end date is the greater of the final average pay benefit or the cash balance benefit earned before the end date. They will also earn a new cash balance benefit for service after the formula end date. In addition, we sponsor non-qualified defined benefit plans subject to Section 409A of the Internal Revenue Code. This plan is for certain highly compensated employees and agents to replace the benefit that cannot be provided by the qualified defined benefit pension plan due to IRS limits. These nonqualified plans generally parallel the qualified plan but offer different payment options. No agent will become a new participant in the nonqualified plan after December 31, 2018. We provide certain health care, life insurance and long-term care benefits for retired employees, their beneficiaries and covered dependents ("other postretirement benefits"). While virtually all U.S. employees continue to have access to the post-retirement health care and life insurance benefits, only those U.S. employees that were hired prior to January 1, 2002, and retired prior to January 1, 2011, (post-65 medical) or January 1, 2020, (life insurance and pre-65 medical) were eligible to receive subsidized benefits. All others pay the full cost of coverage. The long-term care plan was subsidized only for those who retired prior to January 1, 2000, and is no longer accessible. The subsidy level for all benefits varies by plan, age, service and retirement date. The funding policy for all employee benefit plans is to fund the cost of providing pension benefits in the years that the employees and agents are providing service, taking into account the funding status of the trust. For the qualified defined benefit plan, this policy will be subject to an amount no lower than the minimum annual contribution required under the Employee Retirement Income Security Act (“ERISA”), and, generally, not greater than the maximum amount that can be deducted for U.S. federal income tax purposes. While we designate assets to cover the computed liability of the nonqualified pension plan, the assets are not included as part of the asset balances presented in this footnote as they do not qualify as plan assets in accordance with U.S. GAAP. Obligations and Funded Status The plans' combined funded status, reconciled to amounts recognized in the consolidated statements of financial position, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement ​ ​ Pension benefits ​ benefits ​ ​ December 31, ​ December 31, ​ 2020 2019 2020 2019 ​ ​ (in millions) Change in benefit obligation ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefit obligation at beginning of year ​ $ (3,692.1) ​ $ (3,239.2) ​ $ (101.4) ​ $ (98.9) ​ Service cost ​ ​ (72.7) ​ (66.0) ​ ​ — ​ — ​ Interest cost ​ ​ (117.3) ​ (126.5) ​ ​ (2.8) ​ (3.7) ​ Actuarial loss ​ ​ (462.4) ​ (506.4) ​ ​ (11.7) ​ (4.8) ​ Participant contributions ​ ​ — ​ — ​ ​ (6.0) ​ (4.4) ​ Benefits paid ​ ​ 134.3 ​ 123.6 ​ ​ 12.8 ​ 12.2 ​ Plan amendments ​ ​ — ​ 122.4 ​ ​ 1.0 ​ ​ (1.8) ​ Other ​ ​ — ​ ​ — ​ ​ 0.1 ​ ​ — ​ Benefit obligation at end of year ​ $ (4,210.2) ​ $ (3,692.1) ​ $ (108.0) ​ $ (101.4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in plan assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at beginning of year ​ $ 2,926.0 ​ $ 2,498.2 ​ $ 732.8 ​ $ 643.9 ​ Actual return on plan assets ​ ​ 521.3 ​ 520.9 ​ ​ 53.1 ​ 95.5 ​ Employer contribution ​ ​ 60.5 ​ 30.5 ​ ​ 1.5 ​ 1.2 ​ Participant contributions ​ ​ — ​ — ​ ​ 6.0 ​ 4.4 ​ Benefits paid ​ ​ (134.3) ​ (123.6) ​ ​ (12.8) ​ (12.2) ​ Fair value of plan assets at end of year ​ $ 3,373.5 ​ $ 2,926.0 ​ $ 780.6 ​ $ 732.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount recognized in statement of financial position ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other assets ​ $ — ​ $ — ​ $ 675.5 ​ $ 635.1 ​ Other liabilities ​ ​ (836.7) ​ (766.1) ​ ​ (2.9) ​ (3.7) ​ Total ​ $ (836.7) ​ $ (766.1) ​ $ 672.6 ​ $ 631.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount recognized in accumulated other comprehensive (income) loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net actuarial (gain) loss ​ $ 760.0 ​ $ 737.5 ​ $ (22.8) ​ $ (17.4) ​ Prior service benefit ​ ​ (121.0) ​ (137.8) ​ ​ (7.3) ​ (7.3) ​ Pre-tax accumulated other comprehensive (income) loss ​ $ 639.0 ​ $ 599.7 ​ $ (30.1) ​ $ (24.7) ​ ​ The accumulated benefit obligation for all defined benefit pension plans was $4,136.5 million and $3,599.5 million as of December 31, 2020 and 2019, respectively. Employer contributions to the pension plans include contributions made directly to the qualified pension plan assets and contributions from corporate assets to pay nonqualified pension benefits. Benefits paid from the pension plans include both qualified and nonqualified plan benefits. Nonqualified pension plan assets are not included as part of the asset balances presented in this footnote. The nonqualified pension plan assets are held in Rabbi trusts for the benefit of all nonqualified plan participants. The assets held in a Rabbi trust are available to satisfy the claims of general creditors only in the event of bankruptcy. Therefore, these assets are fully consolidated in our consolidated statements of financial position and are not reflected in our funded status as they do not qualify as plan assets under U.S. GAAP. The market value of assets held in these trusts was $394.8 million and $377.8 million as of December 31, 2020 and 2019, respectively. Pension Plan Changes and Plan Gains/Losses During the second quarter of 2019, we amended The Principal Pension Plan and The Principal Financial Group Nonqualified Defined Benefit Plan for Employees to end traditional benefit accruals as of December 31, 2022, and begin cash balance accruals January 1, 2023. We remeasured the associated plan assets and pension benefit obligations as of May 31, 2019, resulting in a net actuarial loss of $59.0 million and a total plan amendment gain of $122.4 million. The net actuarial loss is composed of an increase in benefit obligation of $237.6 million resulting from the reduction in discount rate compared to December 31, 2018, partially offset by a $178.6 million asset gain. The net plan amendment gain was recorded in AOCI and will be amortized over the average future working lifetimes of the plans. For the year ended December 31, 2020, the pension plans had an actuarial loss primarily due to a decrease in the discount rate and change in actuarial assumptions. For the year ended December 31, 2019, the pension plans had an actuarial loss primarily due to a decrease in the discount rate. Other Postretirement Plan Changes and Plan Gains/Losses For the year ended December 31, 2020, the other postretirement benefit plans had an actuarial loss primarily due to a decrease in the discount rate and a higher than expected number of retirees electing medical coverage with the elimination of subsidized benefits. For the year ended December 31, 2019, the other postretirement benefit plans had an actuarial loss primarily due to a decrease in the discount rate and a gain from actual and projected medical claims cost being lower than expected. Effective January 1, 2021, $655.5 million of assets in excess of the expected liability to cover the postretirement medical benefits for retirees were re-designated for non-retiree benefits. The elections were made pursuant to plan provisions which provide for assets in excess of 125% of expected liabilities to fund other benefits covered under the plans. Information for Pension Plans With an Accumulated Benefit Obligation in Excess of Plan Assets For 2020 and 2019, both the qualified and nonqualified plans had accumulated benefit obligations in excess of plan assets. As noted previously, the nonqualified plans have assets that are deposited in trusts that fail to meet the U.S. GAAP requirements to be included in plan assets; however, these assets are included in our consolidated statements of financial position. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Projected benefit obligation ​ $ 4,210.2 ​ $ 3,692.1 ​ Accumulated benefit obligation ​ ​ 4,136.5 ​ 3,599.5 ​ Fair value of plan assets ​ ​ 3,373.5 ​ 2,926.0 ​ ​ ​ Information for Other Postretirement Benefit Plans With an Accumulated Postretirement Benefit Obligation in Excess of Plan Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Accumulated postretirement benefit obligation ​ $ 2.9 ​ $ 3.8 ​ Fair value of plan assets ​ ​ — ​ — ​ ​ Components of Net Periodic Benefit Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension benefits ​ Other postretirement benefits ​ ​ For the year ended December 31, ​ 2020 2019 2018 2020 2019 2018 ​ ​ (in millions) Service cost ​ $ 72.7 ​ $ 66.0 ​ $ 73.0 ​ $ — ​ $ — ​ $ 0.1 ​ Interest cost ​ ​ 117.3 ​ 126.5 ​ 119.5 ​ ​ 2.8 ​ 3.7 ​ 3.5 ​ Expected return on plan assets ​ ​ (156.8) ​ (148.8) ​ (157.0) ​ ​ (36.0) ​ (33.2) ​ (33.6) ​ Amortization of prior service benefit ​ ​ (16.8) ​ (11.3) ​ (3.4) ​ ​ (1.0) ​ (1.2) ​ (13.9) ​ Recognized net actuarial (gain) loss ​ ​ 75.4 ​ 70.1 ​ 67.8 ​ ​ — ​ 0.1 ​ (1.5) ​ Net periodic benefit cost (income) ​ $ 91.8 ​ $ 102.5 ​ $ 99.9 ​ $ (34.2) ​ $ (30.6) ​ $ (45.4) ​ ​ The components of net periodic benefit cost including the service cost component are included in operating expenses on the consolidated statements of operations. The pension plans' actuarial gains and losses are amortized using a straight-line amortization method over the average remaining service period of plan participants. The other postretirement plans use a straight-line amortization over the average future lifetime of its remaining covered group of retirees. For the qualified pension plan, gains and losses are amortized without use of the 10% allowable corridor. For the nonqualified pension plans and other postretirement benefit plans, the corridors allowed are used. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension ​ Other postretirement ​ ​ benefits ​ benefits ​ ​ For the year ended December 31, ​ 2020 2019 2020 2019 ​ ​ (in millions) Other changes recognized in accumulated other comprehensive (income) loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net actuarial (gain) loss ​ $ 97.9 ​ $ 134.3 ​ $ (5.4) ​ $ (57.5) ​ Prior service (benefit) cost ​ ​ — ​ ​ (122.4) ​ ​ (1.0) ​ ​ 1.7 ​ Amortization of net loss ​ ​ (75.4) ​ (70.1) ​ ​ — ​ (0.1) ​ Amortization of prior service benefit ​ ​ 16.8 ​ 11.3 ​ ​ 1.0 ​ 1.2 ​ Total recognized in pre-tax accumulated other comprehensive (income) loss ​ $ 39.3 ​ $ (46.9) ​ $ (5.4) ​ $ (54.7) ​ Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss ​ $ 131.1 ​ $ 55.6 ​ $ (39.6) ​ $ (85.3) ​ ​ Net actuarial (gain) loss and net prior service cost benefit have been recognized in AOCI. ​ Assumptions Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 ​ Discount rate ​ 2.50 % 3.25 % Interest crediting rate - cash balance benefit ​ 5.00 % — % Rate of compensation increase: ​ ​ ​ ​ ​ Cash balance benefit ​ 4.92 % 4.95 % Traditional benefit ​ 2.96 % 2.98 % ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 ​ Discount rate ​ 2.10 % 2.95 % Rate of compensation increase ​ N/A ​ N/A ​ ​ Weighted average assumptions used to determine net periodic benefit cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ Discount rate (1) ​ 3.25 % 3.70 % 3.60 % Expected long-term return on plan assets ​ 5.60 % 5.95 % 6.30 % Interest crediting rate - cash balance benefit ​ 5.00 % — % — % Rate of compensation increase: ​ ​ ​ ​ ​ ​ ​ Cash balance benefit ​ 4.95 % 4.94 % 4.96 % Traditional benefit ​ 2.98 % 2.73 % 2.77 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ Discount rate (2) ​ 2.95 % 3.95 % 3.35 % Expected long-term return on plan assets ​ 4.94 % 5.19 % 4.85 % Rate of compensation increase ​ N/A ​ N/A ​ 2.39 % (1) During the second quarter of 2019, we amended The Principal Pension Plan and The Principal Financial Group Nonqualified Defined Benefit Plan for Employees to end traditional benefit accruals as of December 31, 2022, and begin cash balance accruals January 1, 2023. We remeasured the associated plan assets and pension benefit obligations as of May 31, 2019. A discount rate of 4.15% was used until the remeasurement date at which time a discount rate of 3.70% was used. See "Pension Plan Changes and Plan Gains/Losses" for further details. (2) During the second quarter 2020, subsidy increases provided under the long-term care plan were capped at 5% per calendar year. This change was remeasured as of March 31, 2020. A discount rate of 2.95% was used until the remeasurement date at which time a discount rate of 2.90% was used. The assumed salary growth rates used to project benefits for the projected benefit obligation are age-based for home office employees. The rate labeled cash balance benefit (relative to employees accruing a cash balance) is the lifecount-weighted average rate of salary growth in the coming year only, as the impact of salary assumption for cash balance benefits are limited to the upcoming year service cost. The rate labeled traditional benefit (relative to employees still accruing a final average pay benefit) is the lifecount-weighted average (at each age) of the single annual growth rate at the age that is equivalent to applying the scale from that age to assumed termination or retirement ages. ​ For the pension benefits, the discount rate is determined by projecting future benefit payments inherent in the projected benefit obligation and discounting those cash flows using a spot yield curve for high quality corporate bonds. The plans’ expected benefit payments are discounted to determine a present value using the yield curve and the discount rate is the level rate that produces the same present value. The expected return on plan assets is the long-term rate we expect to be earned based on the long-term investment policy of the plans and the various classes of invested funds. A weighted average rate was developed based on those overall rates and the target asset allocation of the plans. For other postretirement benefits, the discount rate is determined by projecting future benefit payments inherent in the accumulated postretirement benefit obligation and discounting those cash flows using a spot yield curve for high quality corporate bonds. The plans’ expected benefit payments are discounted to determine a present value using the yield curve and the discount rate is the level rate that produces the same present value. The 4.94% expected long-term return on plan assets for 2020 was based on the weighted average expected long-term asset returns for the plans. The expected long-term rates for the home office medical/life, agent medical/life and post-65 medical plans were 5.0%, 4.7% and 4.7%, respectively. Assumed Health Care Cost Trend Rates Used to Determine Net Periodic Benefit Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ Health care cost trend rate assumed for next year under age 65 ​ 6.75 % 6.75 % Health care cost trend rate assumed for next year age 65 and over ​ 6.00 % 6.00 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) ​ 4.50 % 4.50 % Year that the rate reaches the ultimate trend rate (under age 65) ​ 2029 ​ 2028 ​ Year that the rate reaches the ultimate trend rate (65 and older) ​ 2026 ​ 2025 ​ ​ Pension Plan and Other Postretirement Benefit Plan Assets Fair value is defined as the price that would be received to sell an asset in an orderly transaction between market participants at the measurement date (an exit price). The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three levels. ● Level 1 – Fair values are based on unadjusted quoted prices in active markets for identical assets. ● Level 2 – Fair values are based on inputs other than quoted prices within Level 1 that are observable for the asset, either directly or indirectly. ● Level 3 – Fair values are based on significant unobservable inputs for the asset. ​ Our pension plan assets consist of investments in pooled separate accounts and single client separate accounts. Net asset value (“NAV”) of the pooled separate accounts is calculated in a manner consistent with U.S. GAAP for investment companies and is determinative of their fair value. Several of the pooled separate accounts invest in publicly quoted mutual funds or actively managed stocks. The fair value of the underlying mutual funds or stocks is used to determine the NAV of the separate account, which is not publicly quoted. Some of the pooled separate accounts also invest in fixed income securities. The fair value of the underlying securities is based on quoted prices of similar assets and used to determine the NAV of the separate account. Some of the pooled separate accounts invest in real estate properties. The fair value is based on discounted cash flow valuation models that utilize public real estate market data inputs such as transaction prices, market rent growth, vacancy levels, leasing absorption, market capitalization rates and discount rates. The single client separate accounts invest in fixed income securities, hedge funds, a pooled separate account investment and other assets. The fixed income securities include U.S. Treasury bonds for which the fair value is based on quoted prices of identical assets in active markets. The fair value of the other fixed income securities is determined either from prices obtained from third party pricing vendors who use observable market information to determine prices or from internal models using substantially all observable inputs or a matrix pricing valuation approach. The hedge funds are measured at fair value using the NAV per share (or its equivalent) practical expedient and have not been classified in the fair value hierarchy. The NAV of the pooled separate account investment is calculated in a manner consistent with U.S. GAAP for investment companies and is determinative of its fair value. The carrying amounts of other assets, which are highly liquid in nature, are used to approximate fair value. Our other postretirement benefit plan assets consist of cash, investments in fixed income security portfolios and investments in equity security portfolios. Because of the nature of cash, its carrying amount approximates fair value. The fair value of fixed income investment funds, U.S. equity portfolios and international equity portfolios is based on quoted prices in active markets for identical assets. Pension Plan Assets The fair value of the qualified pension plan’s assets by asset category as of the most recent measurement date was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Assets ​ Amount ​ Fair value hierarchy level ​ ​ ​ measured at ​ measured at ​ ​ ​ ​ fair value net asset value Level 1 Level 2 Level 3 ​ ​ ​ (in millions) ​ Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pooled separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large cap equity portfolios (1) ​ $ 712.2 ​ $ — ​ $ — ​ $ 712.2 ​ $ — ​ U.S. small/mid cap equity portfolios (2) ​ 121.6 ​ ​ — ​ — ​ 121.6 ​ — ​ Balanced asset portfolios (3) ​ 103.7 ​ ​ — ​ — ​ 103.7 ​ — ​ International equity portfolios (4) ​ 459.6 ​ ​ — ​ — ​ 459.6 ​ — ​ Real estate investment portfolios (5) ​ 195.1 ​ ​ ​ ​ ​ ​ 195.1 ​ ​ ​ Single client separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ ​ 297.5 ​ ​ — ​ ​ 297.5 ​ ​ — ​ ​ — ​ States and political subdivisions ​ ​ 28.0 ​ ​ — ​ ​ — ​ ​ 28.0 ​ ​ — ​ Corporate ​ ​ 1,223.1 ​ ​ — ​ ​ — ​ ​ 1,223.1 ​ ​ — ​ Commercial mortgage-backed securities ​ ​ 13.6 ​ ​ — ​ ​ — ​ ​ 13.6 ​ ​ — ​ Other debt obligations ​ ​ 6.4 ​ ​ — ​ ​ — ​ ​ 6.4 ​ ​ — ​ Hedge funds (6) ​ ​ 155.8 ​ ​ 155.8 ​ ​ — ​ ​ — ​ ​ — ​ Pooled separate account investment (7) ​ ​ 55.1 ​ ​ — ​ ​ — ​ ​ 55.1 ​ ​ — ​ Other (8) ​ ​ 1.8 ​ ​ — ​ ​ — ​ ​ 1.8 ​ ​ — ​ Total ​ $ 3,373.5 ​ $ 155.8 ​ $ 297.5 ​ $ 2,920.2 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Assets ​ Amount ​ Fair value hierarchy level ​ ​ measured at ​ measured at ​ ​ ​ fair value net asset value Level 1 Level 2 Level 3 ​ ​ (in millions) Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pooled separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large cap equity portfolios (1) ​ $ 509.7 ​ $ — ​ $ — ​ $ 509.7 ​ $ — ​ U.S. small/mid cap equity portfolios (2) ​ 90.9 ​ ​ — ​ — ​ 90.9 ​ — ​ Balanced asset portfolios (3) ​ 78.5 ​ ​ — ​ — ​ 78.5 ​ — ​ International equity portfolios (4) ​ 328.6 ​ ​ — ​ — ​ 328.6 ​ — ​ Real estate investment portfolios (5) ​ 193.5 ​ ​ — ​ — ​ 193.5 ​ — ​ Single client separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ ​ 485.9 ​ ​ — ​ ​ 485.9 ​ ​ — ​ ​ — ​ States and political subdivisions ​ ​ 26.1 ​ ​ — ​ ​ — ​ ​ 26.1 ​ ​ — ​ Corporate ​ ​ 1,009.1 ​ ​ — ​ ​ — ​ ​ 1,009.1 ​ ​ — ​ Commercial mortgage-backed securities ​ ​ 32.7 ​ ​ — ​ ​ — ​ ​ 32.7 ​ ​ — ​ Other debt obligations ​ ​ 7.1 ​ ​ — ​ ​ — ​ ​ 7.1 ​ ​ — ​ Hedge funds (6) ​ ​ 129.0 ​ ​ 129.0 ​ ​ — ​ ​ — ​ ​ — ​ Pooled separate account investment (7) ​ ​ 31.5 ​ ​ — ​ ​ — ​ ​ 31.5 ​ ​ — ​ Other (8) ​ ​ 3.4 ​ ​ — ​ ​ — ​ ​ 3.4 ​ ​ — ​ Total ​ $ 2,926.0 ​ $ 129.0 ​ $ 485.9 ​ $ 2,311.1 ​ $ — ​ (1) The portfolios invest primarily in publicly traded equity securities of large U.S. companies. (2) The portfolios invest primarily in publicly traded equity securities of mid-sized and small U.S. companies. (3) The portfolios are a combination of underlying fixed income and equity investment options. These investment options may include balanced, asset allocation, target-date and target-risk investment options. Although typically lower risk than investment options that invest solely in equities, all investment options in this category have the potential to lose value. (4) The portfolios invest primarily in publicly traded equity securities of non-U.S. companies. (5) The portfolio invests primarily in U.S. commercial real estate properties through a separate account. (6) The hedge funds have varying investment strategies that also have a variety of redemption terms and conditions. We do not have unfunded commitments associated with these hedge funds. (7) The single client separate accounts invest in a money market pooled separate account. (8) Includes cash and net (payables)/receivables for the single client separate accounts. We have established an investment policy that provides the investment objectives and guidelines for the pension plan. Our investment strategy is to achieve the following: ● Obtain a reasonable long-term return consistent with the level of risk assumed and at a cost of operation within prudent levels. Performance benchmarks are monitored. ● Ensure sufficient liquidity to meet the emerging benefit liabilities for the plan. ● Provide for diversification of assets in an effort to avoid the risk of large losses and maximize the investment return to the pension plan consistent with market and economic risk. In administering the qualified pension plan’s asset allocation strategy, we consider the projected liability stream of benefit payments, the relationship between current and projected assets of the plan and the projected actuarial liabilities streams, the historical performance of capital markets adjusted for the perception of future short- and long-term capital market performance and the perception of future economic conditions. According to our investment policy, the target asset allocation for the qualified plan is: ​ ​ ​ ​ ​ ​ ​ ​ Asset category Target allocation ​ Fixed income security portfolios ​ 25 % - 80 % Equity portfolios ​ 5 % - 60 % Real estate investment portfolios ​ ​ ​ ​ 10 % Alternatives ​ ​ ​ ​ 5 % ​ Other Postretirement Benefit Plan Assets The fair value of the other postretirement benefit plans’ assets by asset category as of the most recent measurement date was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Assets ​ Fair value hierarchy level ​ ​ ​ measured at ​ ​ ​ ​ fair value Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 0.5 ​ $ 0.5 ​ $ — ​ $ — ​ Fixed income security portfolios: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income investment funds (1) ​ 625.2 ​ 605.9 ​ 19.3 ​ — ​ U.S. equity portfolios (2) ​ 103.5 ​ 38.2 ​ 65.3 ​ — ​ International equity portfolios (3) ​ 51.4 ​ 18.4 ​ 33.0 ​ — ​ Total ​ $ 780.6 ​ $ 663.0 ​ $ 117.6 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Assets ​ Fair value hierarchy level ​ ​ ​ measured at ​ ​ ​ ​ fair value Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 0.6 ​ $ 0.6 ​ $ — ​ $ — ​ Fixed income security portfolios: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income investment funds (1) ​ 370.5 ​ 331.0 ​ 39.5 ​ — ​ U.S. equity portfolios (2) ​ 254.5 ​ 210.3 ​ 44.2 ​ — ​ International equity portfolios (3) ​ ​ 107.2 ​ 88.9 ​ 18.3 ​ — ​ Total ​ $ 732.8 ​ $ 630.8 ​ $ 102.0 ​ $ — ​ (1) The portfolios invest in various fixed income securities, primarily of U.S. origin. These include, but are not limited to, corporate bonds, residential mortgage-backed securities, commercial mortgage-backed securities, U.S. Treasury securities, agency securities, asset-backed securities and collateralized mortgage obligations. (2) The portfolios invest primarily in publicly traded equity securities of large U.S. companies. (3) The portfolios invest primarily in publicly traded equity securities of non-U.S. companies. As of December 31, 2020 and 2019, $117.6 million and $101.8 million of assets, respectively, in cash, fixed income security portfolios, U.S. equity portfolios and international equity portfolios were included in a trust owned life insurance contract. The investment strategies for the other postretirement benefit plans are similar to those employed by the qualified pension plan. According to our investment policy, the target asset allocation for the other postretirement benefit plans is: ​ ​ ​ ​ ​ Asset category Target allocation ​ U.S. equity portfolios ​ 35 % International equity portfolios ​ 15 % Fixed income security portfolios ​ 50 % ​ Contributions Our funding policy for the qualified pension plan is to fund the plan annually in an amount at least equal to the minimum annual contribution required under ERISA and, generally, not greater than the maximum amount that can be deducted for U.S. federal income tax purposes. We do not anticipate contributions will be needed to satisfy the minimum funding requirements of ERISA for our qualified plan. We are unable to estimate the amount that may be contributed, but it is possible that we may fund the plans in 2021 up to $100.0 million. This includes funding for both our qualified and nonqualified pension plans. While we designate assets to cover the computed liability of the nonqualified plan, the assets are not included as part of the asset balances presented in this footnote as they do not qualify as plan assets in accordance with U.S. GAAP. We may contribute to our other postretirement benefit plans in 2021 pending future analysis. Estimated Future Benefit Payments The estimated future benefit payments, which reflect expected future service, are: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement ​ ​ ​ ​ ​ ​ benefits (gross benefit ​ ​ ​ ​ ​ ​ payments, including ​ ​ Pension benefits prescription drug benefits) ​ ​ (in millions) ​ Year ending December 31: ​ ​ ​ ​ ​ ​ ​ 2021 ​ $ 160.2 ​ $ 15.5 ​ 2022 ​ ​ 159.9 ​ ​ 14.8 ​ 2023 ​ ​ 166.6 ​ ​ 13.5 ​ 2024 ​ ​ 175.8 ​ ​ 12.2 ​ 2025 ​ ​ 179.3 ​ ​ 10.9 ​ 2026-2030 ​ ​ 1,026.0 ​ ​ 38.3 ​ ​ The above table reflects the total estimated future benefits to be paid from the plan, including both our share of the benefit cost and the participants' share of the cost, which is funded by their contributions to the plan. The assumptions used in calculating the estimated future benefit payments are the same as those used to measure the benefit obligation for the year ended December 31, 2020. ​ Defined Benefit Pension Plans Supplemental Information Certain key summary data is shown below separately for qualified and nonqualified plans. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ ​ Qualified ​ Nonqualified ​ ​ ​ ​ Qualified ​ Nonqualified ​ ​ ​ ​ Plan Plan Total Plan Plan Total ​ ​ (in millions) Amount recognized in statement of financial position ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other assets ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ Other liabilities ​ ​ (294.9) ​ ​ (541.8) ​ ​ (836.7) ​ (258.7) ​ ​ (507.4) ​ ​ (766.1) ​ Total ​ $ (294.9) ​ $ (541.8) ​ $ (836.7) ​ $ (258.7) ​ $ (507.4) ​ $ (766.1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount recognized in accumulated other comprehensive loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net actuarial loss ​ $ 563.5 ​ $ 196.5 ​ $ 760.0 ​ $ 567.6 ​ $ 169.9 ​ $ 737.5 ​ Prior service benefit ​ ​ (97.8) ​ ​ (23.2) ​ ​ (121.0) ​ (110.3) ​ ​ (27.5) ​ ​ (137.8) ​ Pre-tax accumulated other comprehensive loss ​ $ 465.7 ​ $ 173.3 ​ $ 639.0 ​ $ 457.3 ​ $ 142.4 ​ $ 599.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Components of net periodic benefit cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service cost ​ $ 66.1 ​ $ 6.6 ​ $ 72.7 ​ $ 59.7 ​ $ 6.3 ​ $ 66.0 ​ Interest cost ​ ​ 101.2 ​ ​ 16.1 ​ ​ 117.3 ​ 108.0 ​ ​ 18.5 ​ ​ 126.5 ​ Expected return on plan assets ​ ​ (156.8) ​ ​ — ​ ​ (156.8) ​ (148.8) ​ ​ — ​ ​ (148.8) ​ Amortization of prior service benefit ​ ​ (12.6) ​ ​ (4.2) ​ ​ (16.8) ​ (7.8) ​ ​ (3.5) ​ ​ (11.3) ​ Recognized net actuarial loss ​ ​ 59.9 ​ ​ 15.5 ​ ​ 75.4 ​ 57.6 ​ ​ 12.5 ​ ​ 70.1 ​ Net periodic benefit cost ​ $ 57.8 ​ $ 34.0 ​ $ 91.8 ​ $ 68.7 ​ $ 33.8 ​ $ 102.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other changes recognized in accumulated other comprehensive (income) loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net actuarial loss ​ $ 55.7 ​ $ 42.2 ​ $ 97.9 ​ $ 80.8 ​ $ 53.5 ​ $ 134.3 ​ Prior service benefit ​ ​ — ​ ​ — ​ ​ — ​ ​ (107.2) ​ ​ (15.2) ​ ​ (122.4) ​ Amortization of net loss ​ ​ (59.8) ​ ​ (15.6) ​ ​ (75.4) ​ (57.6) ​ ​ (12.5) ​ ​ (70.1) ​ Amortization of prior service benefit ​ ​ 12.6 ​ ​ 4.2 ​ ​ 16.8 ​ 7.8 ​ ​ 3.5 ​ ​ 11.3 ​ Total recognized in pre-tax accumulated other comprehensive (income) loss ​ $ 8.5 ​ $ 30.8 ​ $ 39.3 ​ $ (76.2) ​ $ 29.3 ​ $ (46.9) ​ Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss ​ $ 66.3 ​ $ 64.8 ​ $ 131.1 ​ $ (7.5) ​ $ 63.1 ​ $ 55.6 ​ ​ Defined Contribution and Deferred Compensation Plans In addition, we have defined contribution plans that are generally available to all U.S. employees and agents. Eligible participants could not contribute more than $19,500 of their compensation to the plans in 2020. Effective January 1, 2006, we made several changes to the retirement programs. In general, the pension and supplemental executive retirement plan benefit formulas were reduced and the 401(k) matching contribution was increased. Employees who were ages 47 or older with at least ten years of service on December 31, 2005, could elect to retain the prior benefit provisions and forgo receipt of the additional matching contributions. Th

Contingencies, Guarantees, Inde

Contingencies, Guarantees, Indemnifications and Leases	12 Months Ended
	Dec. 31, 2020
Contingencies, Guarantees, Indemnifications and Leases
Contingencies, Guarantees, Indemnifications and Leases	12. Contingencies, Guarantees, Indemnifications and Leases Litigation and Regulatory Contingencies We are regularly involved in litigation, both as a defendant and as a plaintiff, but primarily as a defendant. Litigation naming us as a defendant ordinarily arises out of our business operations as a provider of asset management and accumulation products and services, individual life insurance, specialty benefits insurance and our investment activities. Some of the lawsuits may be class actions, or purport to be, and some may include claims for unspecified or substantial punitive and treble damages. We may discuss such litigation in one of three ways. We accrue a charge to income and disclose legal matters for which the chance of loss is probable and for which the amount of loss can be reasonably estimated. We may disclose contingencies for which the chance of loss is reasonably possible and provide an estimate of the possible loss or range of loss or a statement that such an estimate cannot be made. Finally, we may voluntarily disclose loss contingencies for which the chance of loss is remote in order to provide information concerning matters that potentially expose us to possible losses. In addition, regulatory bodies such as state insurance departments, the SEC, the Financial Industry Regulatory Authority ("FINRA"), the Department of Labor ("DOL") and other regulatory agencies in the U.S. and in international locations in which we do business, regularly make inquiries and conduct examinations or investigations concerning our compliance with, among other things, insurance laws, securities laws, ERISA and laws governing the activities of broker-dealers. We receive requests from regulators and other governmental authorities relating to industry issues and may receive additional requests, including subpoenas and interrogatories, in the future. On November 12, 2014, Frederick Rozo filed a class action lawsuit in the United States District Court for the Southern District of Iowa against Principal Life and us. We were later dismissed as a defendant. The Plaintiff alleged that defendants breached fiduciary duties and engaged in prohibited transactions under ERISA in connection with a general account guaranteed product known as the Principal Fixed Income Option (“PFIO”). On May 12, 2017, the district court certified a nationwide class of participants and beneficiaries who had funds invested in one of the PFIO contracts. On September 25, 2018, the district court granted Principal Life’s motion for summary judgment. On February 3, 2020, the Eighth Circuit Court of Appeals reversed that ruling and remanded the case back to the district court. A bench trial was held before the district court November 3-10, 2020. The court has not yet issued a decision. Principal Life will continue to aggressively defend the case. While the outcome of any pending or future litigation or regulatory matter cannot be predicted, management does not believe any such matter will have a material adverse effect on our business or financial position. As of December 31, 2020, we had no estimated loss accrued related to the legal matter discussed above because we believe the chance of loss from this matter is not probable and the amount of loss cannot be reasonably estimated. To the extent such matters present a reasonably possible chance of loss, we are generally not able to estimate the possible loss or range of loss associated therewith. The outcome of such matters is always uncertain and unforeseen results can occur. It is possible that such outcomes could require us to pay damages or make other expenditures or establish accruals in amounts that we could not estimate at December 31, 2020. Guarantees and Indemnifications In the normal course of business, we have provided guarantees to third parties primarily related to former subsidiaries and joint ventures. The terms of these agreements range in duration and often are not explicitly defined. The maximum exposure under these agreements as of December 31, 2020, was approximately $121.0 million. At inception, the fair value of such guarantees was insignificant. In addition, we believe the likelihood is remote that material payments will be required. Therefore, any liability accrued within our consolidated statements of financial position is insignificant. Should we be required to perform under these guarantees, we generally could recover a portion of the loss from third parties through recourse provisions included in agreements with such parties, the sale of assets held as collateral that can be liquidated in the event performance is required under the guarantees or other recourse generally available to us; therefore, such guarantees would not result in a material adverse effect on our business or financial position. While the likelihood is remote, such outcomes could materially affect net income in a particular quarter or annual period. Furthermore, in connection with our contingent funding agreements, we are required to purchase any principal and interest strips of U.S. Treasury securities that are due and not paid from the associated unconsolidated trusts. The maximum exposure under these agreements as of December 31, 2020, was $750.0 million. See Note 9, Debt, for further details. We manage mandatory privatized social security funds in Chile. By regulation, we have a required minimum guarantee on the funds’ relative return. Because the guarantee has no limitation with respect to duration or amount, the maximum exposure of the guarantee in the future is indeterminable. We are also subject to various other indemnification obligations issued in conjunction with divestitures, acquisitions and financing transactions whose terms range in duration and often are not explicitly defined. Certain portions of these indemnifications may be capped, while other portions are not subject to such limitations; therefore, the overall maximum amount of the obligation under the indemnifications cannot be reasonably estimated. At inception, the fair value of such indemnifications was insignificant. In addition, we believe the likelihood is remote that material payments will be required. Therefore, any liability accrued within our consolidated statements of financial position is insignificant. While we are unable to estimate with certainty the ultimate legal and financial liability with respect to these indemnifications, we believe that performance under these indemnifications would not result in a material adverse effect on our business or financial position. While the likelihood is remote, performance under these indemnifications could materially affect net income in a particular quarter or annual period. Guaranty Funds Under state insurance guaranty fund laws, insurers doing business in a state can be assessed, up to prescribed limits, for certain obligations of insolvent insurance companies to policyholders and claimants. A state’s fund assesses its members based on their pro rata market share of written premiums in the state for the classes of insurance for which the insolvent insurer was engaged. Some states permit member insurers to recover assessments paid through full or partial premium tax offsets. We accrue liabilities for guaranty fund assessments when an assessment is probable, can be reasonably estimated and when the event obligating us to pay has occurred. While we cannot predict the amount and timing of any future assessments, we have established reserves we believe are adequate for assessments relating to insurance companies that are currently subject to insolvency proceedings. As of December 31, 2020 and 2019, the liability balance for guaranty fund assessments, which is not discounted, was $21.1 million and $21.7 million, respectively, and was reported within other liabilities in the consolidated statements of financial position. As of December 31, 2020 and 2019, $9.6 million and $10.0 million, respectively, related to premium tax offsets were included in premiums due and other receivables in the consolidated statements of financial position. ​ Leases As a lessee, we lease office space, data processing equipment, office furniture and office equipment under various operating leases. We also lease buildings and hardware storage equipment under finance leases. Lease assets and liabilities are recognized at the commencement of a lease based on the present value of lease payments over the lease term. We generally use our incremental borrowing rate based on the information available at the lease commencement date to determine the present value of lease payments. Lease term may include options to extend or terminate the lease when it is reasonably certain we will exercise the option. Leases with an initial term of twelve months or less are not recorded on the consolidated statements of financial position. We recognize lease expense for leases on a straight-line basis over the lease term. Some of our lease agreements include payments for property taxes, insurance, utilities or common area maintenance, which are not based on an index or rate. These payments are recognized in net income in the period in which the obligation has occurred. We sublease certain office space to third parties, which are primarily operating leases. We record sublease income on a straight-line basis over the lease term. The lease assets and liabilities were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 ​ 2019 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ Operating lease assets (1) ​ $ 234.9 ​ $ 190.0 ​ Finance lease assets (1) ​ 49.5 ​ ​ 31.4 ​ Total lease assets ​ $ 284.4 ​ $ 221.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ Operating lease liabilities (2) ​ $ 231.4 ​ $ 197.5 ​ Finance lease liabilities (2) ​ 50.1 ​ ​ 31.8 ​ Total lease liabilities ​ $ 281.5 ​ $ 229.3 ​ (1) Operating and finance lease assets are primarily reported within property and equipment on the consolidated statements of financial position. (2) Operating and finance lease liabilities are reported within other liabilities on the consolidated statements of financial position. The lease cost was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ ​ (in millions) Finance lease cost (1): ​ ​ ​ ​ Amortization of right-of-use assets ​ $ 20.5 ​ $ 14.6 Interest on lease liabilities ​ 1.0 ​ ​ 1.0 Operating lease cost (1) ​ 58.7 ​ ​ 55.8 Other lease cost (1) (2) ​ 8.6 ​ ​ 8.0 Sublease income (3) ​ (1.6) ​ ​ (1.7) Total lease cost ​ $ 87.2 ​ $ 77.7 (1) Finance, operating and other lease costs are primarily included in operating expenses on the consolidated statements of operations. (2) Other lease cost primarily reflects variable and short-term lease costs. (3) Sublease income is included in fees and other revenues on the consolidated statements of operations. ​ Rental expense for operating leases for the year ended December 31, 2018, was $36.7 million. Depreciation expense for capital leases for the year ended December 31, 2018, was $12.9 million. Payments for operating leases for the years ended December 31, 2020 and 2019, were $71.6 million and $56.1 million, respectively. Payments for finance leases for the years ended December 31, 2020 and 2019, were $21.2 million and $15.1 million, respectively. The following represents future payments due by period for lease obligations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases Finance leases Total ​ ​ (in millions) ​ For the twelve months ending December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ $ 56.9 ​ $ 21.5 ​ $ 78.4 ​ 2022 ​ ​ 49.8 ​ ​ 13.6 ​ ​ 63.4 ​ 2023 ​ ​ 39.1 ​ ​ 11.4 ​ ​ 50.5 ​ 2024 ​ ​ 30.5 ​ ​ 3.6 ​ ​ 34.1 ​ 2025 ​ ​ 22.8 ​ ​ 1.2 ​ ​ 24.0 ​ 2026 and thereafter ​ ​ 60.8 ​ ​ — ​ ​ 60.8 ​ Total lease payments ​ ​ 259.9 ​ ​ 51.3 ​ ​ 311.2 ​ Less: interest ​ ​ 28.5 ​ ​ 1.2 ​ ​ 29.7 ​ Present value of lease liabilities ​ $ 231.4 ​ $ 50.1 ​ $ 281.5 ​ ​ The weighted-average remaining lease term and weighted-average discount rates were as follows: ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ Weighted-average remaining lease term (in years): ​ ​ ​ Operating leases 6.7 ​ 6.7 ​ Finance leases 3.0 ​ 2.6 ​ ​ ​ ​ ​ ​ ​ Weighted-average discount rate: ​ ​ Operating leases 3.2 % 3.9 % Finance leases 1.8 % 2.7 % ​

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity
Stockholders' Equity	13. Stockholders' Equity Common Stock Dividends ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 Dividends declared per common share ​ $ 2.24 ​ $ 2.18 ​ $ 2.10 ​ ​ Reconciliation of Outstanding Common Shares ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Beginning balance ​ 276.6 ​ 279.5 ​ 289.0 ​ Shares issued ​ 2.6 ​ 2.6 ​ 2.6 ​ Treasury stock acquired ​ (5.9) ​ (5.5) ​ (12.1) ​ Ending balance ​ 273.3 ​ 276.6 ​ 279.5 ​ ​ In February 2016, our Board of Directors authorized a share repurchase program of up to $400.0 million of our outstanding common stock, which was completed in February 2018. In May 2017, our Board of Directors authorized a share repurchase program of up to $250.0 million of our outstanding common stock, which was completed in April 2018. In May 2018, our Board of Directors authorized a share repurchase program of up to $300.0 million of our outstanding common stock, which was completed in December 2018. In November 2018, our Board of Directors authorized a share repurchase program of up to $500.0 million of our outstanding common stock, which was completed in February 2020. In February 2020, our Board of Directors authorized a share repurchase program of up to $900.0 million of our outstanding common stock, which has no expiration date. Shares repurchased under these programs are accounted for as treasury stock, carried at cost and reflected as a reduction to stockholders’ equity. Other Comprehensive Income (Loss) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ Pre-Tax Tax After-Tax ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized gains on available-for-sale securities during the period ​ $ 3,441.4 ​ $ (728.7) ​ $ 2,712.7 ​ Reclassification adjustment for gains included in net income (1) ​ (52.9) ​ 12.6 ​ (40.3) ​ Adjustments for assumed changes in amortization patterns ​ (179.0) ​ 37.6 ​ (141.4) ​ Adjustments for assumed changes in policyholder liabilities ​ (1,478.2) ​ 323.7 ​ (1,154.5) ​ Net unrealized gains on available-for-sale securities ​ 1,731.3 ​ (354.8) ​ 1,376.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized losses on derivative instruments during the period ​ (28.1) ​ ​ 6.5 ​ ​ (21.6) ​ Reclassification adjustment for gains included in net income (3) ​ (27.1) ​ ​ 5.1 ​ ​ (22.0) ​ Adjustments for assumed changes in amortization patterns ​ 2.7 ​ ​ (0.5) ​ ​ 2.2 ​ Adjustments for assumed changes in policyholder liabilities ​ 7.8 ​ ​ (1.6) ​ ​ 6.2 ​ Net unrealized losses on derivative instruments ​ (44.7) ​ ​ 9.5 ​ ​ (35.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign currency translation adjustment during the period ​ ​ (11.7) ​ ​ (2.6) ​ ​ (14.3) ​ Reclassification adjustment for losses included in net income (4) ​ ​ 43.0 ​ ​ 1.9 ​ ​ 44.9 ​ Foreign currency translation adjustment ​ 31.3 ​ ​ (0.7) ​ ​ 30.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized postretirement benefit obligation during the period ​ (91.9) ​ ​ 24.9 ​ ​ (67.0) ​ Amortization of amounts included in net periodic benefit cost (5) ​ 57.6 ​ ​ (15.5) ​ ​ 42.1 ​ Net unrecognized postretirement benefit obligation ​ (34.3) ​ ​ 9.4 ​ ​ (24.9) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income ​ $ 1,683.6 ​ $ (336.6) ​ $ 1,347.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ Pre-Tax Tax After-Tax ​ ​ (in millions) ​ Net unrealized gains on available-for-sale securities during the period ​ $ 4,414.1 ​ $ (947.0) ​ $ 3,467.1 ​ Reclassification adjustment for losses included in net income (1) ​ 47.4 ​ (9.7) ​ 37.7 ​ Adjustments for assumed changes in amortization patterns ​ (293.0) ​ 61.5 ​ (231.5) ​ Adjustments for assumed changes in policyholder liabilities ​ (847.7) ​ 190.5 ​ (657.2) ​ Net unrealized gains on available-for-sale securities ​ 3,320.8 ​ (704.7) ​ 2,616.1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Noncredit component of impairment losses on fixed maturities, available-for-sale during the period ​ 5.2 ​ ​ (1.1) ​ ​ 4.1 ​ Adjustments for assumed changes in amortization patterns ​ (1.4) ​ ​ 0.3 ​ ​ (1.1) ​ Noncredit component of impairment losses on fixed maturities, available-for-sale (2) ​ 3.8 ​ ​ (0.8) ​ ​ 3.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized losses on derivative instruments during the period ​ (0.5) ​ ​ — ​ ​ (0.5) ​ Reclassification adjustment for gains included in net income (3) ​ (23.9) ​ ​ 4.9 ​ ​ (19.0) ​ Adjustments for assumed changes in amortization patterns ​ 3.1 ​ ​ (0.6) ​ ​ 2.5 ​ Adjustments for assumed changes in policyholder liabilities ​ 7.9 ​ ​ (1.9) ​ ​ 6.0 ​ Net unrealized losses on derivative instruments ​ (13.4) ​ ​ 2.4 ​ ​ (11.0) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign currency translation adjustment during the period ​ ​ (112.3) ​ ​ 7.5 ​ ​ (104.8) ​ Reclassification adjustment for losses included in net income (4) ​ ​ 26.1 ​ ​ — ​ ​ 26.1 ​ Foreign currency translation adjustment ​ (86.2) ​ ​ 7.5 ​ ​ (78.7) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized postretirement benefit obligation during the period ​ 43.6 ​ ​ (8.6) ​ ​ 35.0 ​ Amortization of amounts included in net periodic benefit cost (5) ​ 57.7 ​ ​ (15.4) ​ ​ 42.3 ​ Net unrecognized postretirement benefit obligation ​ 101.3 ​ ​ (24.0) ​ ​ 77.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income ​ $ 3,326.3 ​ $ (719.6) ​ $ 2,606.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ Pre-Tax Tax After-Tax ​ ​ (in millions) ​ Net unrealized losses on available-for-sale securities during the period ​ $ (2,517.5) ​ $ 515.4 ​ $ (2,002.1) ​ Reclassification adjustment for losses included in net income (1) ​ 56.4 ​ (5.3) ​ 51.1 ​ Adjustments for assumed changes in amortization patterns ​ 185.9 ​ (39.1) ​ 146.8 ​ Adjustments for assumed changes in policyholder liabilities ​ 346.9 ​ (72.3) ​ 274.6 ​ Net unrealized losses on available-for-sale securities ​ (1,928.3) ​ 398.7 ​ (1,529.6) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Noncredit component of impairment losses on fixed maturities, available-for-sale during the period ​ 39.7 ​ ​ (8.4) ​ ​ 31.3 ​ Adjustments for assumed changes in amortization patterns ​ (5.3) ​ ​ 1.1 ​ ​ (4.2) ​ Adjustments for assumed changes in policyholder liabilities ​ ​ (0.8) ​ ​ 0.1 ​ ​ (0.7) ​ Noncredit component of impairment losses on fixed maturities, available-for-sale (2) ​ 33.6 ​ ​ (7.2) ​ ​ 26.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized gains on derivative instruments during the period ​ 50.4 ​ ​ (3.4) ​ ​ 47.0 ​ Reclassification adjustment for gains included in net income (3) ​ (40.1) ​ ​ 4.2 ​ ​ (35.9) ​ Adjustments for assumed changes in amortization patterns ​ 0.3 ​ ​ (0.1) ​ ​ 0.2 ​ Adjustments for assumed changes in policyholder liabilities ​ 5.7 ​ ​ (1.0) ​ ​ 4.7 ​ Net unrealized gains on derivative instruments ​ 16.3 ​ ​ (0.3) ​ ​ 16.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign currency translation adjustment ​ (303.9) ​ ​ 16.3 ​ ​ (287.6) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized postretirement benefit obligation during the period ​ (125.3) ​ ​ 29.4 ​ ​ (95.9) ​ Amortization of amounts included in net periodic benefit cost (5) ​ 49.0 ​ ​ (14.0) ​ ​ 35.0 ​ Net unrecognized postretirement benefit obligation ​ (76.3) ​ ​ 15.4 ​ ​ (60.9) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss ​ $ (2,258.6) ​ $ 422.9 ​ $ (1,835.7) ​ (1) Pre-tax reclassification adjustments relating to available-for-sale securities are reported in net realized capital gains (losses) on the consolidated statements of operations. (2) Prior to 2020, represents the net impact of (1) unrealized gains resulting from reclassification of previously recognized noncredit impairment losses from OCI to net realized capital gains (losses) for fixed maturities with bifurcated OTTI that had additional credit losses or fixed maturities that previously had bifurcated OTTI that have now been sold or are intended to be sold and (2) unrealized losses resulting from reclassification of noncredit impairment losses for fixed maturities with bifurcated OTTI from net realized capital gains (losses) to OCI. (3) See Note 5, Derivative Financial Instruments, under the caption “Effect of Fair Value and Cash Flow Hedges on Consolidated Statements of Operations” for further details. (4) The 2020 pre-tax reclassification adjustment primarily related to the release of the cumulative translation adjustment from the dissolution of a foreign subsidiary and the net impact of deconsolidated sponsored investment funds and associated net investment hedges. The 2019 pre-tax reclassification adjustment primarily related to deconsolidated sponsored investment funds. The adjustments were reported in net realized capital gains (losses) on the consolidated statements of operations. For the years ended December 31, 2020 and 2019, $8.7 million and $5.7 million, respectively, of this reclassification relates to noncontrolling interest and is reported in net income attributable to noncontrolling interest on the consolidated statements of operations. (5) Amount is comprised of amortization of prior service cost (benefit) and recognized net actuarial (gain) loss, which is reported in operating expenses on the consolidated statements of operations. See Note 11, Employee and Agent Benefits, under the caption “Components of Net Periodic Benefit Cost” for further details. ​ Accumulated Other Comprehensive Income (Loss) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Noncredit ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized ​ component of ​ Net unrealized ​ Foreign ​ Unrecognized ​ Accumulated ​ ​ gains on ​ impairment losses ​ gains ​ currency ​ postretirement ​ other ​ ​ available-for-sale ​ on fixed maturities ​ on derivative ​ translation ​ benefit ​ comprehensive ​ securities (1) available-for-sale (2) instruments adjustment obligation income (loss) ​ ​ (in millions) Balances as of January 1, 2018 ​ $ 1,470.7 ​ $ (58.3) ​ $ 42.7 ​ $ (918.5) ​ $ (371.1) ​ $ 165.5 Other comprehensive loss during the period, net of adjustments ​ (1,580.6) ​ — ​ 51.9 ​ (283.2) ​ (95.9) ​ (1,907.8) Amounts reclassified from AOCI ​ 51.1 ​ 26.4 ​ (35.9) ​ — ​ 35.0 ​ 76.6 Other comprehensive loss ​ (1,529.5) ​ ​ 26.4 ​ ​ 16.0 ​ ​ (283.2) ​ ​ (60.9) ​ ​ (1,831.2) Purchase of subsidiary shares from noncontrolling interest ​ ​ — ​ ​ — ​ ​ — ​ ​ (1.6) ​ ​ — ​ ​ (1.6) Effects of implementation of accounting change related to equity investments, net ​ ​ (1.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (1.0) Effects of implementation of accounting change accounting change related to revenue recognition, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 25.6 ​ ​ — ​ ​ 25.6 Effects of implementation of accounting change related to the reclassification of certain tax effects, net ​ ​ 249.8 ​ ​ (15.2) ​ ​ 5.7 ​ ​ (81.8) ​ ​ (80.9) ​ ​ 77.6 Balances as of December 31, 2018 ​ ​ 190.0 ​ ​ (47.1) ​ ​ 64.4 ​ ​ (1,259.5) ​ ​ (512.9) ​ ​ (1,565.1) Other comprehensive income during the period, net of adjustments ​ ​ 2,578.3 ​ ​ — ​ ​ 8.0 ​ ​ (102.7) ​ ​ 35.0 ​ ​ 2,518.6 Amounts reclassified from AOCI ​ ​ 37.7 ​ ​ 3.0 ​ ​ (19.0) ​ ​ 20.4 ​ ​ 42.3 ​ ​ 84.4 Other comprehensive income ​ ​ 2,616.0 ​ ​ 3.0 ​ ​ (11.0) ​ ​ (82.3) ​ ​ 77.3 ​ ​ 2,603.0 Balances as of December 31, 2019 ​ ​ 2,806.0 ​ ​ (44.1) ​ ​ 53.4 ​ ​ (1,341.8) ​ ​ (435.6) ​ ​ 1,037.9 Other comprehensive income during the period, net of adjustments ​ ​ 1,416.7 ​ ​ — ​ ​ (13.2) ​ ​ (7.3) ​ ​ (67.0) ​ ​ 1,329.2 Amounts reclassified from AOCI ​ ​ (40.3) ​ ​ — ​ ​ (22.0) ​ ​ 36.2 ​ ​ 42.1 ​ ​ 16.0 Other comprehensive income ​ ​ 1,376.4 ​ ​ — ​ ​ (35.2) ​ ​ 28.9 ​ ​ (24.9) ​ ​ 1,345.2 Effects of implementation of accounting change related to credit losses, net ​ ​ (44.1) ​ ​ 44.1 ​ ​ — ​ ​ — ​ ​ — ​ ​ — Balances as of December 31, 2020 ​ $ 4,138.3 ​ $ — ​ $ 18.2 ​ $ (1,312.9) ​ $ (460.5) ​ $ 2,383.1 (1) Net unrealized losses on available-for-sale debt securities for which an allowance for credit loss has been recorded were $2.9 million as of December 31, 2020. (2) Prior to the implementation of authoritative guidance in 2020, the noncredit component of impairment losses on fixed maturities, available-for-sale was included as a separate component of stockholders' equity. Noncontrolling Interest Interests held by unaffiliated parties in consolidated entities are reflected in noncontrolling interest, which represents the noncontrolling partners’ share of the underlying net assets of our consolidated subsidiaries. Noncontrolling interest that is not redeemable is reported in the equity section of the consolidated statements of financial position. The noncontrolling interest holders in certain of our consolidated entities maintain an equity interest that is redeemable at the option of the holder, which may be exercised on varying dates. Since redemption of the noncontrolling interest is outside of our control, this interest is excluded from stockholders’ equity and reported separately as redeemable noncontrolling interest on the consolidated statements of financial position. Our redeemable noncontrolling interest primarily relates to consolidated sponsored investment funds for which interests are redeemed at fair value from the net assets of the funds. For our redeemable noncontrolling interest related to other consolidated subsidiaries, redemptions are required to be purchased at fair value or a value based on a formula that management intended to reasonably approximate fair value based on a fixed multiple of earnings over a measurement period. The carrying value of the redeemable noncontrolling interest is compared to the redemption value at each reporting period. Any adjustments to the carrying amount of the redeemable noncontrolling interest for changes in redemption value prior to exercise of the redemption option are determined after the attribution of net income or loss of the subsidiary and are recognized in the redemption value as they occur. Adjustments to the carrying value of redeemable noncontrolling interest result in adjustments to additional paid-in capital and/or retained earnings. Adjustments are recorded in retained earnings to the extent the redemption value of the redeemable noncontrolling interest exceeds its fair value and will impact the numerator in our earnings per share calculations. All other adjustments to the redeemable noncontrolling interest are recorded in additional paid-in capital. ​ Following is a reconciliation of the changes in the redeemable noncontrolling interest (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Beginning balance ​ $ 264.9 ​ $ 391.2 ​ $ 101.3 ​ Net income (loss) attributable to redeemable noncontrolling interest ​ ​ 7.5 ​ ​ 33.6 ​ ​ (2.1) ​ Redeemable noncontrolling interest of deconsolidated entities (1) ​ ​ (91.9) ​ ​ (505.4) ​ ​ (10.6) ​ Contributions from redeemable noncontrolling interest ​ 136.2 ​ 402.1 ​ 355.0 ​ Distributions to redeemable noncontrolling interest ​ (62.0) ​ (66.3) ​ (36.8) ​ Purchase of subsidiary shares from redeemable noncontrolling interest ​ — ​ (1.1) ​ (7.1) ​ Change in redemption value of redeemable noncontrolling interest ​ 0.2 ​ 5.4 ​ (7.0) ​ Stock-based compensation attributable to redeemable noncontrolling interest ​ ​ 0.1 ​ ​ 0.1 ​ ​ 0.1 ​ Other comprehensive income (loss) attributable to redeemable noncontrolling interest ​ 0.6 ​ 5.3 ​ (1.6) ​ Ending balance ​ $ 255.6 ​ $ 264.9 ​ $ 391.2 ​ (1) We deconsolidated certain sponsored investment funds as they no longer met the requirements for consolidation. Dividend Limitations The declaration and payment of our common stock dividends is subject to the discretion of our Board of Directors and will depend on our overall financial condition, results of operations, capital levels, cash requirements, future prospects, receipt of dividends from Principal Life (as described below), risk management considerations and other factors deemed relevant by the Board. No significant restrictions limit the payment of dividends by us, except those generally applicable to corporations incorporated in Delaware. Under Iowa law, Principal Life may pay dividends only from the earned surplus arising from its business and must receive the prior approval of the Commissioner of Insurance of the State of Iowa (“the Commissioner”) to pay stockholder dividends or make any other distribution if such distribution would exceed certain statutory limitations. Iowa law gives the Commissioner discretion to disapprove requests for distributions in excess of these limitations. Extraordinary dividends include those made, together with dividends and other distributions, within the preceding twelve months that exceed the greater of (i) 10% of Principal Life’s statutory policyholder surplus as of the previous year-end or (ii) the statutory net gain from operations from the previous calendar year, not to exceed earned surplus. Based on this limitation and 2020 statutory results, Principal Life could pay approximately $932.5 million in ordinary stockholder dividends in 2021 without prior regulatory approval. However, because the dividend test is based on dividends previously paid over rolling 12-month periods, if paid before a specified date during 2021, some or all of such dividends may be extraordinary and require regulatory approval.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Measurements
Fair Value Measurements	14. Fair Value Measurements We use fair value measurements to record fair value of certain assets and liabilities and to estimate fair value of financial instruments not recorded at fair value but required to be disclosed at fair value. Certain financial instruments, particularly policyholder liabilities other than investment contracts, are excluded from these fair value disclosure requirements. Valuation Hierarchy Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three levels. The level in the fair value hierarchy within which the fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety considering factors specific to the asset or liability. ● Level 1 – Fair values are based on unadjusted quoted prices in active markets for identical assets or liabilities. ● Level 2 – Fair values are based on inputs other than quoted prices within Level 1 that are observable for the asset or liability, either directly or indirectly. ● Level 3 – Fair values are based on at least one significant unobservable input for the asset or liability. Determination of Fair Value The following discussion describes the valuation methodologies and inputs used for assets and liabilities measured at fair value on a recurring basis. The techniques utilized in estimating the fair value of financial instruments are reliant on the assumptions used. Care should be exercised in deriving conclusions about our business, its value or financial position based on the fair value information of financial instruments presented below. Fair value estimates are made based on available market information and judgments about the financial instrument at a specific point in time. Such estimates do not consider the tax impact of the realization of unrealized gains or losses. In addition, the disclosed fair value may not be realized in the immediate settlement of the financial instrument. We validate prices through an investment analyst review process, which includes validation through direct interaction with external sources, review of recent trade activity or use of internal models. In circumstances where broker quotes are used to value an instrument, we generally receive one non-binding quote. Broker quotes are validated through an investment analyst review process, which includes validation through direct interaction with external sources and use of internal models or other relevant information. We did not make any significant changes to our valuation processes during 2020. Fixed Maturities Fixed maturities include bonds, ABS, redeemable preferred stock and certain non-redeemable preferred securities. When available, the fair value of fixed maturities is based on quoted prices of identical assets in active markets. These are reflected in Level 1 and primarily include U.S. Treasury bonds and actively traded redeemable corporate preferred securities. When quoted prices of identical assets in active markets are not available, our first priority is to obtain prices from third party pricing vendors. We have regular interaction with these vendors to ensure we understand their pricing methodologies and to confirm they are utilizing observable market information. Their methodologies vary by asset class and include inputs such as estimated cash flows, benchmark yields, reported trades, broker quotes, credit quality, industry events and economic events. Fixed maturities with validated prices from pricing services, which includes the majority of our public fixed maturities in all asset classes, are generally reflected in Level 2. Also included in Level 2 are corporate bonds when quoted market prices are not available, for which an internal model using substantially all observable inputs or a matrix pricing valuation approach is used. In the matrix approach, securities are grouped into pricing categories that vary by sector, rating and average life. Each pricing category is assigned a risk spread based on studies of observable public market data from the investment professionals assigned to specific security classes. The expected cash flows of the security are then discounted back at the current Treasury curve plus the appropriate risk spread. Although the matrix valuation approach provides a fair valuation of each pricing category, the valuation of an individual security within each pricing category may also be impacted by company specific factors. ​ If we are unable to price a fixed maturity security using prices from third party pricing vendors or other sources specific to the asset class, we may obtain a broker quote or utilize an internal pricing model specific to the asset utilizing relevant market information, to the extent available and where at least one significant unobservable input is utilized. These are reflected in Level 3 in the fair value hierarchy and can include fixed maturities across all asset classes. As of December 31, 2020, less than 1% of our total fixed maturities were Level 3 securities valued using internal pricing models. The primary inputs, by asset class, for valuations of the majority of our Level 2 investments from third party pricing vendors or our internal pricing valuation approach are described below. U.S. Government and Agencies/Non-U.S. Governments States and Political Subdivisions Corporate RMBS, CMBS, Collateralized Debt Obligations and Other Debt Obligations Equity Securities Equity securities include mutual funds, common stock, non-redeemable preferred stock and required regulatory investments. Fair values of equity securities are determined using quoted prices in active markets for identical assets when available, which are reflected in Level 1. When quoted prices are not available, we may utilize internal valuation methodologies appropriate for the specific asset that use observable inputs such as underlying share prices or the net asset value (“NAV”), which are reflected in Level 2. Fair values might also be determined using broker quotes or through the use of internal models or analysis that incorporate significant assumptions deemed appropriate given the circumstances and consistent with what other market participants would use when pricing such securities, which are reflected in Level 3. Derivatives The fair values of exchange-traded derivatives are determined through quoted market prices, which are reflected in Level 1. Exchange-traded derivatives include futures that are settled daily, which reduces their fair value in the consolidated statements of financial position. The fair values of OTC cleared derivatives are determined through market prices published by the clearinghouses, which are reflected in Level 2. The clearinghouses may utilize the overnight indexed swap (“OIS”) curve in their valuation. Variation margin associated with OTC cleared derivatives is settled daily, which reduces their fair value in the consolidated statements of financial position. The fair values of bilateral OTC derivative instruments are determined using either pricing valuation models that utilize market observable inputs or broker quotes. The majority of our bilateral OTC derivatives are valued with models that use market observable inputs, which are reflected in Level 2. Significant inputs include contractual terms, interest rates, currency exchange rates, credit spread curves, equity prices and volatilities. These valuation models consider projected discounted cash flows, relevant swap curves and appropriate implied volatilities. Certain bilateral OTC derivatives utilize unobservable market data, primarily independent broker quotes that are nonbinding quotes based on models that do not reflect the result of market transactions, which are reflected in Level 3. ​ Our non-cleared derivative contracts are generally documented under ISDA Master Agreements, which provide for legally enforceable set-off and close-out netting of exposures to specific counterparties. Collateral arrangements are bilateral and based on current ratings of each entity. We utilize the LIBOR interest rate curve to value our positions, which includes a credit spread. This credit spread incorporates an appropriate level of nonperformance risk into our valuations given the current ratings of our counterparties, as well as the collateral agreements in place. Counterparty credit risk is routinely monitored to ensure our adjustment for nonperformance risk is appropriate. Our centrally cleared derivative contracts are conducted with regulated centralized clearinghouses, which provide for daily exchange of cash collateral or variation margin equal to the difference in the daily market values of those contracts that eliminates the nonperformance risk on these trades. Interest Rate Contracts. Foreign Exchange Contracts. We use discounted cash flow valuation techniques that utilize observable swap curves and exchange rates as the inputs to determine the fair value of foreign currency swaps. These are reflected in Level 2. Currency forwards are and currency options were valued using observable market inputs, including forward currency exchange rates. These are reflected in Level 2. In addition, we have a limited number of non-standard currency swaps that are and currency options that were valued using broker quotes. These are reflected within Level 3. Equity Contracts. We use an option pricing model using observable implied volatilities, dividend yields, index prices and swap curves as the inputs to determine the fair value of equity options. These are reflected in Level 2. Credit Contracts. We use either the ISDA Credit Default Swap Standard discounted cash flow model that utilizes observable default probabilities and recovery rates as inputs to determine the fair value of credit default swaps. These are reflected in Level 2. In addition, we have a limited number of credit default swaps that are valued using broker quotes. These are reflected within Level 3. Other Investments Other investments reported at fair value include invested assets of consolidated sponsored investment funds, unconsolidated sponsored investment funds, other investment funds reported at fair value, equity method real estate investments for which the fair value option was elected and certain nonredeemable preferred stock. In addition, in 2019 we had commercial mortgage loans of consolidated VIEs for which the fair value option was elected and certain redeemable preferred stock. Invested assets of consolidated sponsored investment funds include equity securities, fixed maturities and derivative assets, for which fair values are determined as previously described, and are reflected in Level 1 and Level 2 The fair value of unconsolidated sponsored investment funds and other investment funds is determined using the NAV of the fund. The NAV of the fund represents the price at which we would be able to initiate a transaction. Investments for which the NAV represents a quoted price in an active market for identical assets are reflected in Level 1. Investments that do not have a quoted price in an active market are reflected in Level 2. Commercial mortgage loans of a consolidated VIE were valued using the more observable fair value of the liabilities of the consolidated collateralized financing entity (“CCFE”) under the measurement alternative guidance and were reflected in Level 2. The liabilities were affiliated so were not reflected in our consolidated results. The trust was unwound in the third quarter of 2019. Equity method real estate investments for which the fair value option was elected are reflected in Level 3. The equity method real estate investments consist of underlying real estate and debt. The real estate fair value is estimated using a discounted cash flow valuation model that utilizes public real estate market data inputs such as transaction prices, market rents, vacancy levels, leasing absorption, market cap rates and discount rates. The debt fair value is estimated using a discounted cash flow analysis based on our incremental borrowing rate for similar borrowing arrangements. The fair value of certain redeemable and nonredeemable preferred stock is based on an internal model using unobservable inputs, which is reflected in Level 3. The redeemable preferred stock was sold in the third quarter of 2020. Cash Equivalents Certain cash equivalents are reported at fair value on a recurring basis and include money market instruments and other short-term investments with maturities of three months or less. Fair values of these cash equivalents may be determined using public quotations, when available, which are reflected in Level 1. When public quotations are not available, because of the highly liquid nature of these assets, carrying amounts may be used to approximate fair values, which are reflected in Level 2. Separate Account Assets Separate account assets include equity securities, debt securities, cash equivalents and derivative instruments, for which fair values are determined as previously described, and are reflected in Level 1, Level 2 and Level 3. Separate account assets also include commercial mortgage loans, for which the fair value is estimated by discounting the expected total cash flows using market rates that are applicable to the yield, credit quality and maturity of the loans. The market clearing spreads vary based on mortgage type, weighted average life, rating and liquidity. These are reflected in Level 3. Finally, separate account assets include real estate, for which the fair value is estimated using discounted cash flow valuation models that utilize various public real estate market data inputs. In addition, each property is appraised annually by an independent appraiser. The real estate included in separate account assets is recorded net of related mortgage encumbrances for which the fair value is estimated using discounted cash flow analysis based on our incremental borrowing rate for similar borrowing arrangements. The real estate within the separate accounts is reflected in Level 3. Investment and Universal Life Contracts Certain universal life, annuity and other investment contracts include embedded derivatives that have been bifurcated from the host contract and are measured at fair value on a recurring basis, which are reflected in Level 3. The key assumptions for calculating the fair value of the embedded derivative liabilities are market assumptions (such as equity market returns, interest rate levels, market volatility and correlations) and policyholder behavior assumptions (such as lapse, mortality, utilization and withdrawal patterns). Risk margins are included in the policyholder behavior assumptions. The assumptions are based on a combination of historical data and actuarial judgment. The embedded derivative liabilities are valued using models that incorporate a spread reflecting our own creditworthiness. The assumption for our own nonperformance risk for investment contracts and any embedded derivatives bifurcated from certain universal life, annuity and investment contracts is based on the current market credit spreads for debt-like instruments we have issued and are available in the market. Other Liabilities Derivative liabilities of consolidated sponsored investment funds are reported at fair value within other liabilities. Fair values of these derivatives are determined as previously described and are reflected in Level 2. Certain obligations reported in other liabilities included embedded derivatives of the forecasted transactions to deliver underlying securities of structured investments to third parties. The fair value of the embedded derivatives was calculated based on the value of the underlying securities that were valued based on prices obtained from third party pricing vendors as utilized and described in our discussion of how fair value is determined for fixed maturities, which was reflected in Level 2. The certificates matured in the second quarter of 2020. Assets and Liabilities Measured at Fair Value on a Recurring Basis Assets and liabilities measured at fair value on a recurring basis were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Assets/ ​ Amount ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (liabilities) ​ measured at ​ Fair value hierarchy level ​ ​ ​ measured at ​ net asset ​ ​ ​ ​ fair value value (4) Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 2,111.5 ​ $ — ​ $ 1,768.3 ​ $ 343.2 ​ $ — ​ Non-U.S. governments ​ 1,073.7 ​ ​ — ​ 1.1 ​ 1,072.6 ​ — ​ States and political subdivisions ​ 9,167.8 ​ ​ — ​ — ​ 9,167.8 ​ — ​ Corporate ​ 47,354.8 ​ ​ — ​ — ​ 47,064.0 ​ 290.8 ​ Residential mortgage-backed pass-through securities ​ 2,986.8 ​ ​ — ​ — ​ 2,986.8 ​ — ​ Commercial mortgage-backed securities ​ 4,942.3 ​ ​ — ​ — ​ 4,929.1 ​ 13.2 ​ Collateralized debt obligations (1) ​ 4,027.5 ​ ​ — ​ — ​ 4,000.3 ​ 27.2 ​ Other debt obligations ​ 7,045.9 ​ ​ — ​ — ​ 7,016.7 ​ 29.2 ​ Total fixed maturities, available-for-sale ​ 78,710.3 ​ ​ — ​ 1,769.4 ​ 76,580.5 ​ 360.4 ​ Fixed maturities, trading ​ 532.1 ​ ​ — ​ 0.5 ​ 531.6 ​ — ​ Equity securities ​ 2,013.4 ​ ​ — ​ 659.7 ​ 1,353.7 ​ — ​ Derivative assets (2) ​ 463.5 ​ ​ — ​ — ​ 462.9 ​ 0.6 ​ Other investments ​ 746.3 ​ ​ 75.7 ​ 252.8 ​ 385.9 ​ 31.9 ​ Cash equivalents ​ 1,466.4 ​ ​ — ​ 38.3 ​ 1,428.1 ​ — ​ Sub-total excluding separate account assets ​ 83,932.0 ​ ​ 75.7 ​ 2,720.7 ​ 80,742.7 ​ 392.9 ​ Separate account assets ​ 175,951.4 ​ ​ 155.8 ​ 102,550.5 ​ 64,351.9 ​ 8,893.2 ​ Total assets ​ $ 259,883.4 ​ $ 231.5 ​ $ 105,271.2 ​ $ 145,094.6 ​ $ 9,286.1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts (3) ​ $ (467.8) ​ $ — ​ $ — ​ $ — ​ $ (467.8) ​ Derivative liabilities (2) ​ ​ (186.1) ​ ​ — ​ ​ — ​ ​ (180.4) ​ ​ (5.7) ​ Other liabilities ​ (0.4) ​ ​ — ​ — ​ (0.4) ​ — ​ Total liabilities ​ $ (654.3) ​ $ — ​ $ — ​ $ (180.8) ​ $ (473.5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net assets ​ $ 259,229.1 ​ $ 231.5 ​ $ 105,271.2 ​ $ 144,913.8 ​ $ 8,812.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Assets/ ​ Amount ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (liabilities) ​ measured at ​ Fair value hierarchy level ​ ​ ​ measured at ​ net asset ​ ​ ​ ​ fair value value (4) Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 1,724.2 ​ $ — ​ $ 1,320.0 ​ $ 404.2 ​ $ — ​ Non-U.S. governments ​ 996.2 ​ ​ — ​ 1.4 ​ 994.8 ​ — ​ States and political subdivisions ​ 7,490.0 ​ ​ — ​ — ​ 7,490.0 ​ — ​ Corporate ​ 40,647.4 ​ ​ — ​ 18.5 ​ 40,547.2 ​ 81.7 ​ Residential mortgage-backed pass-through securities ​ 2,982.4 ​ ​ — ​ — ​ 2,982.4 ​ — ​ Commercial mortgage-backed securities ​ 4,850.2 ​ ​ — ​ — ​ 4,837.3 ​ 12.9 ​ Collateralized debt obligations (1) ​ 3,215.3 ​ ​ — ​ — ​ 3,016.3 ​ 199.0 ​ Other debt obligations ​ 8,200.5 ​ ​ — ​ — ​ 8,109.2 ​ 91.3 ​ Total fixed maturities, available-for-sale ​ 70,106.2 ​ ​ — ​ 1,339.9 ​ 68,381.4 ​ 384.9 ​ Fixed maturities, trading ​ 675.9 ​ ​ — ​ 0.5 ​ 675.1 ​ 0.3 ​ Equity securities ​ 1,879.4 ​ ​ — ​ 645.8 ​ 1,233.6 ​ — ​ Derivative assets (2) ​ 294.7 ​ ​ — ​ — ​ 265.4 ​ 29.3 ​ Other investments ​ 796.0 ​ ​ 78.3 ​ 335.2 ​ 343.5 ​ 39.0 ​ Cash equivalents ​ 1,299.0 ​ ​ — ​ 40.9 ​ 1,258.1 ​ — ​ Sub-total excluding separate account assets ​ 75,051.2 ​ ​ 78.3 ​ 2,362.3 ​ 72,157.1 ​ 453.5 ​ Separate account assets ​ 165,468.0 ​ ​ 129.0 ​ 95,652.5 ​ 60,718.5 ​ 8,968.0 ​ Total assets ​ $ 240,519.2 ​ $ 207.3 ​ $ 98,014.8 ​ $ 132,875.6 ​ $ 9,421.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts (3) ​ $ (214.2) ​ $ — ​ $ — ​ $ — ​ $ (214.2) ​ Derivative liabilities (2) ​ ​ (217.7) ​ ​ — ​ ​ — ​ ​ (201.4) ​ ​ (16.3) ​ Other liabilities (3) ​ (98.9) ​ ​ — ​ — ​ (98.9) ​ — ​ Total liabilities ​ $ (530.8) ​ $ — ​ $ — ​ $ (300.3) ​ $ (230.5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net assets ​ $ 239,988.4 ​ $ 207.3 ​ $ 98,014.8 ​ $ 132,575.3 ​ $ 9,191.0 ​ (1) Primarily consists of collateralized loan obligations backed by secured corporate loans. (2) Within the consolidated statements of financial position, derivative assets are reported with other investments and derivative liabilities are reported with other liabilities. The amounts are presented gross in the tables above to reflect the presentation on the consolidated statements of financial position; however, are presented net for purposes of the rollforward in the Changes in Level 3 Fair Value Measurements tables. Refer to Note 5, Derivative Financial Instruments, for further information on fair value by class of derivative instruments. (3) Includes bifurcated embedded derivatives that are reported at net asset (liability) fair value within the same line item in the consolidated statements of financial position in which the host contract is reported. (4) Certain investments are measured at fair value using the NAV per share (or its equivalent) practical expedient and have not been classified in the fair value hierarchy. Other investments using the NAV practical expedient consist of certain fund interests that are restricted until maturity with unfunded commitments totaling $15.1 million and $19.9 million as of December 31, 2020 and December 31, 2019, respectively. Separate account assets using the NAV practical expedient consist of hedge funds with varying investment strategies that also have a variety of redemption terms and conditions. We do not have unfunded commitments associated with these hedge funds. ​ Changes in Level 3 Fair Value Measurements The reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ Total realized/unrealized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gains (losses) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ ​ Net ​ ​ ​ ​ ​ ​ ​ Ending ​ ​ (liability) ​ ​ ​ purchases, ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ balance ​ Included ​ Included in ​ sales, ​ ​ ​ ​ ​ ​ ​ (liability) ​ ​ as of ​ in net ​ other ​ issuances ​ Transfers ​ Transfers ​ balance as of ​ ​ January 1, ​ income ​ comprehensive ​ and ​ into ​ out of ​ December 31, ​ 2020 (2) income (3) settlements (4) Level 3 Level 3 2020 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 81.7 ​ $ (0.9) ​ $ 5.2 ​ $ 118.0 ​ $ 342.0 ​ $ (255.2) ​ $ 290.8 Commercial mortgage-backed securities ​ 12.9 ​ (1.3) ​ 1.4 ​ ​ (0.1) ​ 0.3 ​ — ​ 13.2 Collateralized debt obligations ​ 199.0 ​ (2.3) ​ (21.9) ​ ​ 183.0 ​ — ​ (330.6) ​ 27.2 Other debt obligations ​ 91.3 ​ — ​ (1.4) ​ ​ (37.9) ​ 46.1 ​ (68.9) ​ 29.2 Total fixed maturities, available-for-sale ​ 384.9 ​ (4.5) ​ (16.7) ​ ​ 263.0 ​ 388.4 ​ (654.7) ​ 360.4 Fixed maturities, trading ​ ​ 0.3 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (0.3) ​ ​ — Other investments ​ 39.0 ​ 6.3 ​ (2.9) ​ ​ (10.5) ​ — ​ — ​ 31.9 Separate account assets (1) ​ 8,968.0 ​ 463.7 ​ — ​ ​ (538.5) ​ — ​ — ​ 8,893.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ (214.2) ​ (254.9) ​ (0.3) ​ ​ 1.6 ​ — ​ — ​ (467.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ 13.0 ​ 11.8 ​ — ​ ​ (3.4) ​ — ​ ​ (26.5) ​ (5.1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ ​ ​ Total realized/unrealized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gains (losses) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending ​ ​ (liability) ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ balance ​ ​ ​ Included in ​ sales, ​ ​ ​ ​ ​ ​ ​ (liability) ​ ​ as of ​ Included ​ other ​ issuances ​ Transfers ​ Transfers ​ balance as of ​ ​ January 1, ​ in net ​ comprehensive ​ and ​ into ​ out of ​ December 31, ​ 2019 income (2) income (3) settlements (4) Level 3 Level 3 2019 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ 4.6 ​ $ — ​ $ — ​ $ (4.6) ​ $ — ​ $ — ​ $ — Corporate ​ 57.9 ​ — ​ 2.5 ​ ​ 17.2 ​ 4.1 ​ — ​ 81.7 Commercial mortgage-backed securities ​ 9.5 ​ (3.8) ​ 3.4 ​ ​ 2.4 ​ 3.7 ​ (2.3) ​ 12.9 Collateralized debt obligations ​ 8.3 ​ (2.6) ​ 0.9 ​ ​ 122.5 ​ 69.9 ​ — ​ 199.0 Other debt obligations ​ 58.5 ​ — ​ 0.8 ​ ​ 100.0 ​ 8.3 ​ (76.3) ​ 91.3 Total fixed maturities, available-for-sale ​ 138.8 ​ (6.4) ​ 7.6 ​ ​ 237.5 ​ 86.0 ​ (78.6) ​ 384.9 Fixed maturities, trading ​ — ​ — ​ — ​ ​ 0.3 ​ — ​ — ​ 0.3 Other investments ​ 17.2 ​ 6.0 ​ — ​ ​ 5.8 ​ 10.0 ​ — ​ 39.0 Separate account assets (1) ​ 8,615.5 ​ 739.9 ​ — ​ ​ (214.2) ​ — ​ (173.2) ​ 8,968.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ (45.2) ​ (145.5) ​ (0.2) ​ ​ (23.3) ​ — ​ — ​ (214.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 3.1 ​ ​ (0.8) ​ ​ — ​ ​ 10.7 ​ ​ — ​ ​ — ​ ​ 13.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ ​ ​ ​ Total realized/unrealized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gains (losses) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending ​ ​ (liability) ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ balance ​ ​ ​ Included in ​ sales, ​ ​ ​ ​ ​ ​ ​ (liability) ​ ​ as of ​ Included ​ other ​ issuances ​ Transfers ​ Transfers ​ balance as of ​ ​ January 1, ​ in net ​ comprehensive ​ and ​ into ​ out of ​ December 31, ​ 2018 income (2) income (3) settlements (4) Level 3 Level 3 2018 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ 7.4 ​ $ — ​ $ (0.1) ​ $ (1.4) ​ $ — ​ $ (1.3) ​ $ 4.6 Corporate ​ 128.0 ​ (1.0) ​ (0.1) ​ ​ (15.2) ​ 1.0 ​ (54.8) ​ 57.9 Commercial mortgage-backed securities ​ 10.6 ​ (3.5) ​ 0.2 ​ ​ 0.1 ​ 3.6 ​ (1.5) ​ 9.5 Collateralized debt obligations ​ 125.0 ​ (0.9) ​ 0.2 ​ ​ 66.3 ​ 54.7 ​ (237.0) ​ 8.3 Other debt obligations ​ 2.3 ​ — ​ (0.2) ​ ​ 147.4 ​ — ​ (91.0) ​ 58.5 Total fixed maturities, available-for-sale ​ 273.3 ​ (5.4) ​ — ​ ​ 197.2 ​ 59.3 ​ (385.6) ​ 138.8 Fixed maturities, trading ​ — ​ — ​ — ​ ​ 3.7 ​ — ​ (3.7) ​ — Equity securities ​ ​ 2.7 ​ ​ 12.9 ​ ​ — ​ ​ (15.6) ​ ​ — ​ ​ — ​ ​ — Other investments ​ 6.5 ​ 1.7 ​ — ​ ​ 9.0 ​ — ​ — ​ 17.2 Separate account assets (1) ​ 7,651.4 ​ 869.5 ​ (0.3) ​ ​ 133.7 ​ 2.3 ​ (41.1) ​ 8,615.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ (160.3) ​ 107.5 ​ 0.1 ​ ​ 7.5 ​ — ​ — ​ (45.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 18.1 ​ ​ (20.2) ​ ​ — ​ ​ 5.2 ​ ​ — ​ ​ — ​ ​ 3.1 (1) Gains and losses for separate account assets do not impact net income as the change in value of separate account assets is offset by a change in value of separate account liabilities. Foreign currency translation adjustments related to the Principal International segment separate account assets are recorded in AOCI and are offset by foreign currency translation adjustments of the corresponding separate account liabilities. (2) Both realized gains (losses) and mark-to-market unrealized gains (losses) are generally reported in net realized capital gains (losses) within the consolidated statements of operations. Realized and unrealized gains (losses) on certain securities with an investment objective to realize economic value through mark-to-market changes are reported in net investment income within the consolidated statements of operations. Changes in unrealized gains (losses) included in net income relating to positions still held were: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Assets ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ Commercial mortgage-backed securities ​ $ (1.2) ​ $ (2.9) ​ $ (1.9) Collateralized debt obligations ​ (2.2) ​ (2.6) ​ (0.9) Total fixed maturities, available-for-sale ​ (3.4) ​ (5.5) ​ (2.8) Other investments ​ 5.3 ​ 6.0 ​ 1.7 Separate account assets ​ 385.5 ​ 697.1 ​ 829.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ Investment and universal life contracts ​ (262.1) ​ (146.0) ​ 109.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ Net derivative assets (liabilities) ​ 9.9 ​ 5.3 ​ (18.4) ​ (3) Includes foreign currency translation adjustments related to our Principal International segment. Changes in unrealized gains (losses) included in OCI relating to positions still held were: ​ ​ ​ ​ ​ For the year ended ​ ​ December 31, 2020 ​ ​ ​ (in millions) Assets ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ Corporate ​ $ 11.9 Commercial mortgage-backed securities ​ ​ 1.5 Collateralized debt obligations ​ ​ (0.3) Total fixed maturities, available-for-sale ​ ​ 13.1 Other investments ​ ​ (2.9) ​ ​ ​ ​ Liabilities ​ ​ ​ Investment and universal life contracts ​ ​ (0.3) ​ (4) Gross purchases, sales, issuances and settlements were: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ sales, issuances ​ ​ Purchases Sales Issuances Settlements and settlements ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 169.2 ​ $ (5.5) ​ $ — ​ $ (45.7) ​ $ 118.0 ​ Commercial mortgage-backed securities ​ — ​ — ​ — ​ (0.1) ​ (0.1) ​ Collateralized debt obligations ​ 182.5 ​ — ​ — ​ 0.5 ​ 183.0 ​ Other debt obligations ​ 14.3 ​ — ​ — ​ (52.2) ​ (37.9) ​ Total fixed maturities, available-for-sale ​ 366.0 ​ (5.5) ​ — ​ (97.5) ​ 263.0 ​ Other investments ​ 0.5 ​ (11.0) ​ — ​ — ​ (10.5) ​ Separate account assets (5) ​ 309.2 ​ ​ (658.2) ​ ​ (396.1) ​ 206.6 ​ (538.5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ — ​ — ​ (23.0) ​ 24.6 ​ 1.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ — ​ (3.4) ​ — ​ — ​ (3.4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ sales, issuances ​ ​ Purchases Sales Issuances Settlements and settlements ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ — ​ $ — ​ $ — ​ $ (4.6) ​ $ (4.6) ​ Corporate ​ 41.9 ​ (1.4) ​ — ​ (23.3) ​ 17.2 ​ Commercial mortgage-backed securities ​ 2.4 ​ — ​ — ​ — ​ 2.4 ​ Collateralized debt obligations ​ 124.7 ​ — ​ — ​ (2.2) ​ 122.5 ​ Other debt obligations ​ 107.7 ​ — ​ — ​ (7.7) ​ 100.0 ​ Total fixed maturities, available-for-sale ​ 276.7 ​ (1.4) ​ — ​ (37.8) ​ 237.5 ​ Fixed maturities, trading ​ ​ 0.5 ​ ​ — ​ ​ — ​ ​ (0.2) ​ ​ 0.3 ​ Other investments ​ 10.7 ​ (4.9) ​ — ​ — ​ 5.8 ​ Separate account assets (5) ​ 279.1 ​ ​ (526.4) ​ ​ (280.4) ​ 313.5 ​ (214.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ — ​ — ​ (33.4) ​ 10.1 ​ (23.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 1.9 ​ 8.8 ​ — ​ — ​ 10.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ sales, issuances ​ ​ Purchases Sales Issuances Settlements and settlements ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ — ​ $ — ​ $ — ​ $ (1.4) ​ $ (1.4) ​ Corporate ​

Statutory Insurance Financial I

Statutory Insurance Financial Information	12 Months Ended
	Dec. 31, 2020
Statutory Insurance Financial Information
Statutory Insurance Financial Information	15. Statutory Insurance Financial Information Principal Life, the largest indirect subsidiary of PFG, prepares statutory financial statements in accordance with the accounting practices prescribed or permitted by the Insurance Division of the Department of Commerce of the State of Iowa (the “Iowa Insurance Division”). The Iowa Insurance Division recognizes only statutory accounting practices prescribed or permitted by the State of Iowa for determining and reporting the financial condition and results of operations of an insurance company to determine its solvency under the Iowa Insurance Law. The National Association of Insurance Commissioners' (“NAIC”) Accounting Practices and Procedures Manual has been adopted as a component of prescribed practices by the State of Iowa. The Commissioner has the right to permit other specific practices that deviate from prescribed practices. Statutory accounting practices differ from U.S. GAAP primarily due to charging policy acquisition costs to expense as incurred, establishing reserves using different actuarial assumptions, valuing investments on a different basis and not admitting certain assets, including certain net deferred income tax assets. For the year ended, December 31, 2019, Principal Life’s use of prescribed statutory accounting practices resulted in higher statutory surplus of $862.1 million relative to the accounting practices and procedures of the NAIC due to its accounting for reserve credits associated with a reinsurance transaction with an affiliated reinsurer. Effective June 2020, the affiliated reinsurer became accredited in the State of Iowa and the reserve credits were no longer considered a prescribed practice. In addition, as of December 31, 2019, Principal Life’s permitted statutory accounting practice relating to variable annuities with a guaranteed living benefit rider resulted in lower statutory surplus of $151.3 million relative to carrying certain interest rate swaps at book value rather than fair value, as if they received hedge accounting treatment for statutory. Effective January 1, 2020, the Iowa Insurance Division approved our request to discontinue the use of this permitted practice due to changes in the practices and procedures of the NAIC. Principal Life cedes certain term and universal life insurance statutory reserves to our affiliated reinsurance subsidiaries on a funds withheld coinsurance basis. The reserves are secured by cash, invested assets and financing provided by highly rated third parties. As of December 31, 2020 and 2019, our affiliated reinsurance subsidiaries assumed statutory reserves of $8,978.2 million and $7,902.3 million from Principal Life, respectively. In the states of Vermont and Delaware, the affiliated reinsurers had permitted and prescribed practices allowing for the admissibility of certain assets backing these reserves. As of December 31, 2020 and 2019, assets admitted under these practices totaled $3,731.0 million and $3,358.0 million, respectively. Life and health insurance companies are subject to certain risk-based capital (“RBC”) requirements as specified by the NAIC. Under those requirements, the amount of capital and surplus maintained by a life and health insurance company is to be determined based on the various risk factors related to it. As of December 31, 2020, Principal Life met the minimum RBC requirements. Statutory net income and statutory capital and surplus of Principal Life were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of or for the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Statutory net income ​ $ 915.9 ​ $ 989.3 ​ $ 1,017.6 ​ Statutory capital and surplus ​ ​ 5,682.4 ​ 5,193.4 ​ 5,319.6 ​ ​

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2020
Segment Information
Segment Information	16. Segment Information We provide financial products and services through the following segments: Retirement and Income Solutions, Principal Global Investors, Principal International and U.S. Insurance Solutions. In addition, we have a Corporate segment. The segments are managed and reported separately because they provide different products and services, have different strategies or have different markets and distribution channels. The Retirement and Income Solutions segment provides retirement and related financial products and services primarily to businesses, their employees and other individuals. The segment is organized into Retirement and Income Solutions – Fee, which includes full service accumulation, trust services, individual variable annuities and revenues and expenses associated with the purchase of the Acquired Business; and Retirement and Income Solutions – Spread, which includes individual fixed annuities, investment only, pension risk transfer and banking services. The Principal Global Investors segment provides asset management services to our asset accumulation business, our insurance operations, the Corporate segment and third party clients. This segment also includes our mutual fund business. The Principal International segment has operations in Latin America (Brazil, Chile and Mexico) and Asia (China, Hong Kong Special Administrative Region, India and Southeast Asia). We focus on locations with large middle classes, favorable demographics and growing long-term savings, ideally with voluntary or mandatory pension markets. We entered these locations through acquisitions, start-up operations and joint ventures. The U.S. Insurance Solutions segment focuses on solutions for individuals and small-to-medium sized businesses and their employees. The segment is organized into Specialty Benefits insurance, which provides group dental and vision insurance, individual and group disability insurance, critical illness, accident, group life insurance and non-medical fee-for-service claims administration; and Individual Life insurance, which provides universal life, variable universal life, indexed universal life and traditional life insurance. Our Corporate segment manages the assets representing capital that has not been allocated to any other segment. Financial results of the Corporate segment primarily reflect our financing activities (including financing costs), income on capital not allocated to other segments, inter-segment eliminations, income tax risks and certain income, expenses and other adjustments not allocated to the segments based on the nature of such items. Results of Principal Securities, Inc. (“PSI”), our retail broker-dealer and registered investment advisor (“RIA”); RobustWealth, Inc. (“RobustWealth”), our financial technology company; and our exited group medical and long-term care insurance businesses are reported in this segment. Management uses segment pre-tax operating earnings in evaluating performance, which is consistent with the financial results provided to and discussed with securities analysts. We determine segment pre-tax operating earnings by adjusting U.S. GAAP income before income taxes for pre-tax net realized capital gains (losses), as adjusted, pre-tax other adjustments that management believes are not indicative of overall operating trends and certain adjustments related to equity method investments and noncontrolling interest. While these items may be significant components in understanding and assessing the consolidated financial performance, management believes the presentation of pre-tax operating earnings enhances the understanding of our results of operations by highlighting pre-tax earnings attributable to the normal, ongoing operations of the business. The pre-tax net realized capital gains (losses), as adjusted, excluded from pre-tax operating earnings reflects consolidated U.S. GAAP pre-tax net realized capital gains (losses) excluding the following items that are included in pre-tax operating earnings: ● Periodic settlements and accruals on derivative instruments not designated as hedging instruments, ● Certain market value adjustments of derivatives and embedded derivatives and ● Certain market value adjustments of derivative instruments used to economically hedge embedded derivatives. Pre-tax net realized capital gains (losses), as adjusted, are further adjusted for: ● Amortization of hedge accounting book value adjustments for certain discontinued hedges, ● Certain hedge accounting market value revenue adjustments, ● Certain market value adjustments to fee revenues, ● Pre-tax net realized capital gains (losses) adjustments related to equity method investments, ● Pre-tax net realized capital gains (losses) adjustments related to sponsored investment funds, ● Recognition of deferred front-end fee revenues for sales charges on retirement and life insurance products and services, ● Related changes in the amortization pattern of DAC and related actuarial balances, ● Certain hedge accounting market value expense adjustments and ● Net realized capital gains (losses) distributed. Segment operating revenues reflect consolidated U.S. GAAP total revenues excluding: ● Net realized capital gains (losses), except periodic settlements and accruals on derivatives not designated as hedging instruments and certain market value adjustments of derivative instruments used to economically hedge embedded derivatives, and their impact on: ● Amortization of hedge accounting book value adjustments for certain discontinued hedges, ● Certain hedge accounting market value revenue adjustments, ● Certain market value adjustments to fee revenues, ● Pre-tax net realized capital gains (losses) adjustments related to equity method investments, ● Pre-tax net realized capital gains (losses) adjustments related to sponsored investment funds and ● Recognition of deferred front-end fee revenues for sales charges on retirement and life insurance products and services. ● Pre-tax other adjustments and income taxes of equity method investments and ● Pre-tax other adjustments management believes are not indicative of overall operating trends. The accounting policies of the segments are consistent with the accounting policies for the consolidated financial statements, with the exception of: (1) pension and other postretirement employee benefits (“OPEB”) cost allocations, (2) certain expenses deemed to benefit the entire organization and (3) income tax allocations. For purposes of determining pre-tax operating earnings, the segments are allocated the service component of pension and other postretirement benefit costs. The Corporate segment reflects the non-service components of pension and other postretirement benefit costs as assumptions are established and funding decisions are managed from a company-wide perspective. Additionally, the Corporate segment reflects expenses that benefit the entire organization for which the segments are not able to influence the spend. This includes expenses such as public company costs, executive management costs, acquisition and disposition costs, among others. The Corporate segment functions to absorb the risk inherent in interpreting and applying tax law. For purposes of determining non-GAAP operating earnings, the segments are allocated tax adjustments consistent with the positions we took on tax returns. The Corporate segment results reflect any differences between the tax returns and the estimated resolution of any disputes. ​ The following tables summarize select financial information by segment, including operating revenues for our products and services, and reconcile segment totals to those reported in the consolidated financial statements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) Assets: ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 207,288.4 ​ $ 192,698.1 ​ Principal Global Investors ​ ​ 2,294.3 ​ 2,363.3 ​ Principal International ​ ​ 51,707.6 ​ 48,857.6 ​ U.S. Insurance Solutions ​ ​ 31,438.9 ​ 28,669.6 ​ Corporate ​ ​ 3,898.5 ​ 3,499.2 ​ Total consolidated assets ​ $ 296,627.7 ​ $ 276,087.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Operating revenues by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions – Fee ​ $ 2,149.8 ​ $ 2,003.0 ​ $ 1,783.7 ​ Retirement and Income Solutions – Spread ​ ​ 5,353.7 ​ ​ 6,951.4 ​ ​ 5,493.3 ​ Total Retirement and Income Solutions (1) ​ ​ 7,503.5 ​ ​ 8,954.4 ​ ​ 7,277.0 ​ Principal Global Investors (2) ​ ​ 1,539.1 ​ 1,505.8 ​ 1,736.3 ​ Principal International ​ ​ 1,096.8 ​ 1,523.2 ​ 1,372.9 ​ U.S. Insurance Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Specialty Benefits insurance ​ ​ 2,525.4 ​ 2,493.6 ​ 2,326.4 ​ Individual Life insurance ​ ​ 1,955.0 ​ 1,955.6 ​ 1,763.6 ​ Eliminations ​ ​ (0.2) ​ (0.2) ​ (0.2) ​ Total U.S. Insurance Solutions ​ ​ 4,480.2 ​ 4,449.0 ​ 4,089.8 ​ Corporate ​ ​ (39.7) ​ (39.3) ​ (51.2) ​ Total segment operating revenues ​ ​ 14,579.9 ​ 16,393.1 ​ 14,424.8 ​ Net realized capital gains (losses), net of related revenue adjustments ​ ​ 195.3 ​ (98.5) ​ (132.3) ​ Adjustments related to equity method investments ​ ​ (33.5) ​ ​ (72.5) ​ ​ (55.3) ​ Total revenues per consolidated statements of operations ​ $ 14,741.7 ​ $ 16,222.1 ​ $ 14,237.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-tax operating earnings (losses) by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 966.9 ​ $ 874.0 ​ $ 922.2 ​ Principal Global Investors ​ ​ 512.9 ​ 483.3 ​ 562.1 ​ Principal International ​ ​ 243.6 ​ 390.7 ​ 272.6 ​ U.S. Insurance Solutions ​ ​ 239.9 ​ 521.6 ​ 467.0 ​ Corporate ​ ​ (326.4) ​ (380.3) ​ (269.4) ​ Total segment pre-tax operating earnings ​ ​ 1,636.9 ​ 1,889.3 ​ 1,954.5 ​ Pre-tax net realized capital gains (losses), as adjusted (3) ​ ​ 63.6 ​ (140.9) ​ (126.4) ​ Adjustments related to equity method investments and noncontrolling interest ​ ​ (7.0) ​ ​ (55.1) ​ ​ (43.7) ​ Income before income taxes per consolidated statements of operations ​ $ 1,693.5 ​ $ 1,693.3 ​ $ 1,784.4 ​ (1) Reflects inter-segment revenues of $342.6 million, $357.8 million and $393.6 million for the years ended December 31, 2020, 2019 and 2018, respectively. (2) Reflects inter-segment revenues of $273.8 million, $264.9 million and $262.8 million for the years ended December 31, 2020, 2019 and 2018, respectively. ​ (3) Pre-tax net realized capital gains (losses), as adjusted, is derived as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Net realized capital gains (losses) ​ $ 302.6 ​ $ (52.8) ​ $ (75.4) ​ Derivative and hedging-related revenue adjustments ​ ​ (132.9) ​ (80.4) ​ (64.9) ​ Market value adjustments to fee revenues ​ ​ (1.6) ​ — ​ 0.1 ​ Adjustments related to equity method investments ​ ​ (1.5) ​ ​ 2.6 ​ ​ (5.4) ​ Adjustments related to sponsored investment funds ​ ​ 17.3 ​ ​ 23.6 ​ ​ 12.9 ​ Recognition of front-end fee revenue ​ ​ 11.4 ​ 8.5 ​ 0.4 ​ Net realized capital gains (losses), net of related revenue adjustments ​ ​ 195.3 ​ (98.5) ​ (132.3) ​ Amortization of deferred acquisition costs and other actuarial balances ​ ​ (26.8) ​ (40.8) ​ (27.0) ​ Capital (gains) losses distributed ​ ​ (49.9) ​ (68.2) ​ 14.4 ​ Market value adjustments of embedded derivatives ​ ​ (55.0) ​ 66.6 ​ 18.5 ​ Pre-tax net realized capital gains (losses), as adjusted (a) ​ $ 63.6 ​ $ (140.9) ​ $ (126.4) ​ (a) As adjusted before noncontrolling interest capital gains (losses). The following is a summary of income tax expense (benefit) allocated to our segments for purposes of determining non-GAAP operating earnings. Segment income taxes are reconciled to income taxes reported on our consolidated statements of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Income tax expense (benefit) by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 106.6 ​ $ 71.8 ​ $ 85.6 ​ Principal Global Investors ​ ​ 141.9 ​ 121.8 ​ 149.1 ​ Principal International ​ ​ 62.0 ​ 106.8 ​ 73.3 ​ U.S. Insurance Solutions ​ ​ 47.9 ​ 101.8 ​ 85.7 ​ Corporate ​ ​ (87.9) ​ (82.0) ​ (36.7) ​ Total segment income taxes from operating earnings ​ ​ 270.5 ​ 320.2 ​ 357.0 ​ Tax expense (benefit) related to net realized capital losses, as adjusted ​ ​ 28.2 ​ 1.3 ​ (71.4) ​ Certain adjustments related to equity method investments and noncontrolling interest ​ ​ (33.7) ​ ​ (72.3) ​ ​ (54.9) ​ Total income taxes per consolidated statements of operations ​ $ 265.0 ​ $ 249.2 ​ $ 230.7 ​ ​ The following is a summary of depreciation and amortization expense allocated to our segments for purposes of determining pre-tax operating earnings. Segment depreciation and amortization is reconciled to depreciation and amortization included in operating expenses in our consolidated statements of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Depreciation and amortization expense by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 69.1 ​ $ 48.2 ​ $ 32.5 ​ Principal Global Investors ​ ​ 21.6 ​ 18.9 ​ 21.9 ​ Principal International ​ ​ 56.0 ​ 58.6 ​ 59.6 ​ U.S. Insurance Solutions ​ ​ 25.1 ​ 25.0 ​ 26.2 ​ Corporate ​ ​ 14.8 ​ 16.1 ​ 10.8 ​ Total depreciation and amortization expense included in our consolidated statements of operations ​ $ 186.6 ​ $ 166.8 ​ $ 151.0 ​ ​

Revenues from Contracts with Cu

Revenues from Contracts with Customers	12 Months Ended
	Dec. 31, 2020
Revenues from Contracts with Customers
Revenues from Contracts with Customers	17. Revenues from Contracts with Customers The following tables summarize disaggregation of revenues from contracts with customers, including select financial information by segment, and reconcile totals to those reported in the consolidated financial statements. Revenues from contracts with customers are included in fees and other revenues on the consolidated statements of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Revenue from contracts with customers by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions – Fee $ 591.2 $ 455.5 $ 252.4 ​ Retirement and Income Solutions – Spread ​ ​ 8.6 ​ 9.3 ​ 10.5 ​ Total Retirement and Income Solutions ​ ​ 599.8 ​ 464.8 ​ 262.9 ​ Principal Global Investors ​ ​ 1,511.2 ​ 1,456.7 ​ 1,700.5 ​ Principal International ​ ​ 439.2 ​ 462.2 ​ 477.1 ​ U.S. Insurance Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Specialty Benefits insurance ​ ​ 14.8 ​ 14.9 ​ 14.8 ​ Individual Life insurance ​ ​ 48.6 ​ 51.2 ​ 42.4 ​ Eliminations ​ ​ (0.2) ​ (0.2) ​ (0.2) ​ Total U.S. Insurance Solutions ​ ​ 63.2 ​ 65.9 ​ 57.0 ​ Corporate ​ ​ 154.9 ​ 160.4 ​ 161.4 ​ Total segment revenue from contracts with customers ​ ​ 2,768.3 ​ 2,610.0 ​ 2,658.9 ​ Adjustments for fees and other revenues not within the scope of revenue recognition guidance (1) ​ ​ 1,733.0 ​ 1,791.4 ​ 1,614.4 ​ Pre-tax other adjustments (2) ​ ​ 9.8 ​ 8.5 ​ 0.5 ​ Total fees and other revenues per consolidated statements of operations $ 4,511.1 $ 4,409.9 $ 4,273.8 ​ (1) Fees and other revenues not within the scope of the revenue recognition guidance primarily represent revenue on contracts accounted for under the financial instruments or insurance contracts standards. (2) Pre-tax other adjustments relate to the recognition of deferred front-end fee revenues for sales charges on retirement and life insurance products and certain market value adjustments to fee revenues. Retirement and Income Solutions - Fee Retirement and Income Solutions - Fee offers service and trust agreements for defined contribution retirement plans, including 401(k) plans, 403(b) plans, and employee stock ownership plans. The investment components of these service agreements are in the form of mutual fund offerings. In addition, plan sponsor retirement plan trust and custody services are also available through an affiliated trust company. With the Acquired Business, services and trust agreements are also offered to non-retirement customers including insurance companies, endowments and other financial institutions. Fees and other revenues are earned for administrative activities performed for the defined contribution retirement plans including recordkeeping and reporting as well as trust and custody, asset management and investment services. Fees and other revenues are earned for administrative activities performed for non-retirement plan customers including trust and custody services, defined benefit administration and investment management activities. The majority of these activities are performed daily over time. Fee-for-service transactions are also provided upon client request. These services are considered distinct or grouped into a bundle until a distinct performance obligation is identified. Some performance obligations are considered a series of distinct services, which are substantially the same and have the same pattern of transfer to the customer. Fees and other revenues can be based on a fixed contractual rate for these services or can be variable based upon contractual rates applied to the market value of the client's investment portfolio each day. If the consideration for this series of performance obligations is based on daily market value, it is considered variable each day as the services are performed over time. The consideration becomes unconstrained and thus recognized as revenue for each day’s series of distinct services once the market value of the clients’ investment portfolios is determined at market close or carried over at the end of the day for days when the market is closed. Additionally, fixed fees and other revenues are recognized point-in-time as fee-for-service transactions upon completion. ​ The types of revenues from contracts with customers were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Administrative service fee revenue (1) ​ $ 589.2 ​ $ 453.7 ​ $ 250.7 ​ Other fee revenue ​ 2.0 ​ 1.8 ​ 1.7 ​ Total revenues from contracts with customers ​ 591.2 ​ 455.5 ​ 252.4 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 1,130.4 ​ 1,139.0 ​ 1,132.9 ​ Total fees and other revenues ​ 1,721.6 ​ 1,594.5 ​ 1,385.3 ​ Premiums and other considerations ​ 5.0 ​ 3.5 ​ 4.0 ​ Net investment income ​ 423.2 ​ 405.0 ​ 394.4 ​ Total operating revenues ​ $ 2,149.8 ​ $ 2,003.0 ​ $ 1,783.7 ​ (1) Includes fee revenue for the Acquired Business in 2020 and 2019. Retirement and Income Solutions - Spread Retirement and Income Solutions – Spread offers individual retirement accounts (“IRAs”) through Principal Bank, which are primarily funded by retirement savings rolled over from qualified retirement plans. The IRAs are held in savings accounts, money market accounts and certificates of deposit. Revenues are earned through fees as the performance of establishing and maintaining IRA accounts is completed. Fee-for-service transactions are also provided upon client request. The establishment fees and annual maintenance fees are accrued into earnings over a period of time using the average account life. Upfront and recurring bank fees are related to performance obligations that have the same pattern of transfer to the customer and are recognized in income over time with control transferred to the customers utilizing the output method. These fees are based on a fixed contractual rate. Fixed fees and other revenues are also recognized point-in-time as fee-for-service transactions upon completion. Additionally, commission income is earned on advisory services provided to customers. The revenues are earned over time as the service is performed based upon contractual rates applied to the market value of the clients' portfolios. The types of revenues from contracts with customers were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) ​ Deposit account fee revenue ​ $ 8.4 ​ $ 9.3 ​ $ 10.5 ​ Commission income ​ ​ 0.2 ​ ​ — ​ ​ — ​ Total revenues from contracts with customers ​ 8.6 ​ 9.3 ​ 10.5 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 9.5 ​ 13.9 ​ 12.5 ​ Total fees and other revenues ​ 18.1 ​ 23.2 ​ 23.0 ​ Premiums and other considerations ​ 3,216.0 ​ 4,859.2 ​ 3,631.9 ​ Net investment income ​ 2,119.6 ​ 2,069.0 ​ 1,838.4 ​ Total operating revenues ​ $ 5,353.7 ​ $ 6,951.4 ​ $ 5,493.3 ​ ​ ​ Principal Global Investors Fees and other revenues earned for asset management, investment advisory and distribution services provided to institutional and retail clients are based largely upon contractual rates applied to the specified amounts of the clients’ portfolios. Each service is a distinct performance obligation, or a series of distinct services that are a single performance obligation in that the services are substantially the same and have the same pattern of transfer to the customer. Fees and other revenues received for performance obligations such as asset management and other services are typically recognized over time utilizing the output method as the service is performed. Performance fees and transaction fees on certain accounts are recognized in income when the probability of significant reversal will not occur upon resolution of the uncertainty, which could be based on a variety of factors such as market performance or other internal metrics. Asset management fees are accrued each month based on the fee terms within the applicable agreement and are generally billed quarterly when values used for the calculation are available. Management fees and performance fees are variable consideration as they are subject to fluctuation based on assets under management (“AUM”) and other constraints. These fees are not recognized until unconstrained at the end of each reporting period. The types of revenues from contracts with customers were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Management fee revenue ​ $ 1,298.4 ​ $ 1,239.1 ​ $ 1,244.5 ​ Other fee revenue (1) ​ 212.8 ​ 217.6 ​ 456.0 ​ Total revenues from contracts with customers ​ ​ 1,511.2 ​ 1,456.7 ​ 1,700.5 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ ​ 22.3 ​ 38.5 ​ 30.4 ​ Total fees and other revenues ​ ​ 1,533.5 ​ 1,495.2 ​ 1,730.9 ​ Net investment income ​ ​ 5.6 ​ 10.6 ​ 5.4 ​ Total operating revenues ​ $ 1,539.1 ​ $ 1,505.8 ​ $ 1,736.3 ​ (1) During the third quarter of 2018, we recognized a $253.1 million accelerated performance fee resulting from the realignment of a real estate investment team. Principal International Fees and other revenues are earned for asset management and distribution services provided to retail and institutional clients in addition to trustee and/or administrative services performed for retirement savings plans. Each service is considered a distinct performance obligation; however, if the services are not distinct on their own, we combine them into a distinct bundle or we have a series of distinct services that are substantially the same and have the same pattern of transfer to the customer. Fees and other revenues are typically based upon contractual rates applied to the market value of the clients’ investment portfolios and are considered variable consideration. The transaction price generally includes the amount determined at the end of the reporting period, whereby fees are deducted from the clients’ investment portfolios and are recognized as revenue when no longer constrained and satisfied as the services are performed over time utilizing the output method. In addition, payments to customers can take the form of an incentive given by us to entice the customer to purchase its goods or services. Incentives offered to customers are recognized as part of the transaction price as a reduction of revenue either over the period the customer remains in order to receive the incentive or monthly throughout the life of the contract. Incentive-based fees are recognized in income when the probability of significant reversal will not occur upon the resolution of the uncertainty, which is based on market performance. Fees for managing customers’ mandatory retirement savings accounts in Chile are collected with each monthly deposit made by our customers. If a customer stops contributing before retirement age, we collect no fees but services are still provided. We recognize revenue from these contracts as services are performed over the life of the contract and review annually. ​ The types of revenues from contracts with customers were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ (in millions) ​ Management fee revenue ​ $ 435.3 ​ $ 459.3 ​ $ 472.1 ​ Other fee revenue ​ 3.9 ​ 2.9 ​ 5.0 ​ Total revenues from contracts with customers ​ 439.2 ​ 462.2 ​ 477.1 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 5.6 ​ 6.3 ​ 7.3 ​ Total fees and other revenues ​ 444.8 ​ 468.5 ​ 484.4 ​ Premiums and other considerations ​ 156.6 ​ 393.3 ​ 317.2 ​ Net investment income ​ 495.4 ​ 661.4 ​ 571.3 ​ Total operating revenues ​ $ 1,096.8 ​ $ 1,523.2 ​ $ 1,372.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues from contracts with customers by region: ​ ​ ​ ​ Latin America ​ $ 323.5 ​ $ 351.5 ​ $ 370.8 ​ Asia ​ 115.9 ​ 111.0 ​ 106.3 ​ Principal International corporate / regional offices ​ 0.9 ​ 0.9 ​ 0.9 ​ Eliminations ​ (1.1) ​ (1.2) ​ (0.9) ​ Total revenues from contracts with customers ​ $ 439.2 ​ $ 462.2 ​ $ 477.1 ​ ​ U.S. Insurance Solutions Fees and other revenues are earned for administrative services performed including recordkeeping and reporting services for fee-for-service products, nonqualified benefit plans, separate accounts and dental networks. Services within contracts are not distinct on their own; however, we combine the services into a distinct bundle and account for the bundle as a single performance obligation, which is satisfied over time utilizing the output method as services are rendered. The transaction price corresponds with the performance completed to date, for which the value is recognized as revenue during the period. Variability of consideration is resolved at the end of each period and payments are due when billed. Commission income is earned through sponsored brokerage services. Performance obligations are satisfied at a point in time, upon delivery of a placed case, and the transaction price calculated per the compensation schedule is recognized as revenue. ​ The types of revenues from contracts with customers were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Specialty Benefits insurance: ​ ​ ​ ​ Administrative service fees ​ $ 14.8 ​ $ 14.9 ​ $ 14.8 ​ Total revenues from contracts with customers ​ 14.8 ​ 14.9 ​ 14.8 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 19.3 ​ 19.6 ​ 20.6 ​ Total fees and other revenues ​ 34.1 ​ 34.5 ​ 35.4 ​ Premiums and other considerations ​ 2,330.7 ​ 2,292.7 ​ 2,134.1 ​ Net investment income ​ 160.6 ​ 166.4 ​ 156.9 ​ Total operating revenues ​ $ 2,525.4 ​ $ 2,493.6 ​ $ 2,326.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individual Life insurance: ​ ​ ​ ​ Administrative service fees ​ $ 21.8 ​ $ 24.3 ​ $ 22.8 ​ Commission income ​ 26.8 ​ 26.9 ​ 19.6 ​ Total revenues from contracts with customers ​ 48.6 ​ 51.2 ​ 42.4 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 849.8 ​ 875.9 ​ 727.0 ​ Total fees and other revenues ​ 898.4 ​ 927.1 ​ 769.4 ​ Premiums and other considerations ​ 329.1 ​ 317.9 ​ 322.4 ​ Net investment income ​ 727.5 ​ 710.6 ​ 671.8 ​ Total operating revenues ​ $ 1,955.0 ​ $ 1,955.6 ​ $ 1,763.6 ​ ​ Corporate Fees and other revenues are earned on the performance of selling and servicing of securities and related products offered through PSI, an introducing broker-dealer registered with the FINRA. PSI enters into selling and distribution agreements with the obligation to sell or distribute the securities products, such as mutual funds, annuities and products sold through RIAs, to individual clients in return for a front-end sales charges, 12b-1 service fees, annuity fees and asset-based fees. Front-end sales charges, 12b-1 fees and annuity fees are related to a single sale and are earned at the time of sale. PSI also enters into agreements with individual customers to provide securities trade execution and custody through a brokerage services platform in return for ticket charge and other service fee revenue. These services are bundled as one single distinct service referred to as brokerage services. This revenue is related to distinct transactions and is earned at a point in time. PSI also enters into agreements with individual customers to provide trade execution, clearing services, custody services and investment research services through our proprietary offered fee-based products. These services are bundled as one single distinct service referred to as advisory services. In addition, for outside RIA business PSI performs sales and distribution services only. The revenues are earned over time as the service is performed utilizing the output method. A majority of our revenue is based upon contractual rates applied to the market value of the clients’ portfolios and considered variable consideration. ​ The Corporate segment also includes inter-segment eliminations of fees and other revenues. The types of revenues from contracts with customers were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ ​ (in millions) ​ Commission income ​ $ 316.6 ​ $ 320.2 ​ $ 316.1 ​ Other fee revenue ​ ​ 59.1 ​ ​ 46.1 ​ ​ 35.4 ​ Eliminations ​ (220.8) ​ (205.9) ​ (190.1) ​ Total revenues from contracts with customers ​ 154.9 ​ 160.4 ​ 161.4 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ (303.9) ​ (301.8) ​ (316.3) ​ Total fees and other revenues ​ (149.0) ​ (141.4) ​ (154.9) ​ Net investment income ​ 109.3 ​ 102.1 ​ 103.7 ​ Total operating revenues ​ $ (39.7) ​ $ (39.3) ​ $ (51.2) ​ ​ Contract Costs Sales compensation and other incremental costs of obtaining a contract are capitalized and amortized over the period of contract benefit if the costs are expected to be recovered. The contract cost asset, which is included in other assets on the consolidated statements of financial position, was $173.0 million and $157.0 million as of December 31, 2020 and December 31, 2019, respectively. We apply the practical expedient for certain costs where we recognize the incremental costs of obtaining these contracts as an expense when incurred if the amortization period of the assets is one year or less. These costs, along with costs that are not deferrable, are included in operating expenses on the consolidated statements of operations. Deferred contract costs consist primarily of commissions and variable compensation. We amortize capitalized contract costs on a straight-line basis over the expected contract life, reflecting lapses as they are incurred. Deferred contract costs are subject to impairment testing on an annual basis, or when a triggering event occurs that could warrant an impairment. To the extent future revenues less future maintenance expenses are not adequate to cover the asset balance, an impairment is recognized. For the years ended December 31, 2020, 2019 and 2018, $24.8 million, $24.4 million and $23.8 million, respectively, of amortization expense was recorded in operating expenses on the consolidated statements of operations and no impairment loss was recognized in relation to the costs capitalized.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2020
Stock-Based Compensation Plans
Stock-Based Compensation Plans	18. Stock-Based Compensation Plans As of December 31, 2020, we had the 2020 Directors Stock Plan, the 2014 Stock Incentive Plan, the Employee Stock Purchase Plan, the 2014 Directors Stock Plan, the Amended and Restated 2010 Stock Incentive Plan, the 2005 Directors Stock Plan, the Stock Incentive Plan and the Directors Stock Plan ("Stock-Based Compensation Plans"). As of May 20, 2014, no new grants will be made under the Amended and Restated 2010 Stock Incentive Plan or the 2005 Directors Stock Plan. No grants have been made under the Stock Incentive Plan or the Directors Stock Plan since at least 2005 As of December 31, 2020, the maximum number of new shares of common stock available for grant under the 2014 Stock Incentive Plan and the 2020 Directors Stock Plan was 4.0 million. ​ For awards with graded vesting, we use an accelerated expense attribution method. The compensation cost that was charged against net income for stock-based awards granted under the Stock-Based Compensation Plans was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Compensation cost ​ $ 86.7 ​ $ 78.7 ​ $ 77.5 ​ Related income tax benefit ​ ​ 17.1 ​ 16.8 ​ 16.7 ​ Capitalized as part of an asset ​ ​ 1.5 ​ 1.7 ​ 1.9 ​ ​ Nonqualified Stock Options Nonqualified stock options were granted to certain employees under the 2014 Stock Incentive Plan, the Amended and Restated 2010 Stock Incentive Plan and the Stock Incentive Plan. Options outstanding were granted at an exercise price equal to the fair market value of our common stock on the date of grant and expire ten years after the grant date. These options have graded vesting over a three-year The following is a summary of the status of all of our stock option plans: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ average ​ ​ ​ ​ Number of options exercise price Intrinsic value ​ ​ (in millions) ​ ​ ​ ​ (in millions) Options outstanding as of January 1, 2020 5.3 ​ $ 48.42 ​ ​ ​ ​ Granted ​ 1.4 ​ ​ 51.73 ​ ​ ​ ​ Exercised ​ 0.1 ​ ​ 29.56 ​ ​ ​ ​ Canceled ​ 0.1 ​ ​ 51.81 ​ ​ ​ ​ Options outstanding as of December 31, 2020 ​ 6.5 ​ $ 49.52 ​ $ 27.5 ​ Options vested or expected to vest as of December 31, 2020 ​ 6.5 ​ $ 49.52 ​ $ 27.5 ​ Options exercisable as of December 31, 2020 ​ 4.2 ​ $ 47.38 ​ $ 27.5 ​ ​ The total intrinsic value of stock options exercised was $3.4 million, $2.4 million and $18.7 million during 2020, 2019, and 2018, respectively. The following is a summary of weighted-average remaining contractual lives for stock options outstanding and the range of exercise prices on the stock options as of December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ Number of options ​ average remaining Range of exercise prices outstanding contractual life ​ ​ (in millions) ​ ​ $27.46 - $41.13 ​ 1.6 ​ 3.3 ​ $41.14 - $51.53 ​ 1.0 ​ 3.7 ​ $51.54 - $52.41 ​ 1.3 ​ 9.1 ​ $52.42 - $62.75 ​ 1.2 ​ 8.1 ​ $62.76 - $63.98 ​ 1.4 ​ 6.7 ​ $27.46 - $63.98 ​ 6.5 ​ ​ ​ ​ The weighted-average remaining contractual lives for stock options exercisable is approximately 6.1 years as of December 31, 2020. ​ The fair value of stock options is estimated using the Black-Scholes option pricing model. The following is a summary of the assumptions used in this model for the stock options granted during the period: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, Options 2020 2019 2018 Expected volatility ​ ​ 25.7 % ​ 23.3 % ​ 26.0 % Expected term (in years) ​ ​ 7.0 ​ ​ 7.0 ​ ​ 7.0 ​ Risk-free interest rate ​ ​ 1.3 % ​ 2.6 % ​ 2.8 % Expected dividend yield ​ ​ 4.33 % ​ 4.07 % ​ 3.19 % Weighted average estimated fair value ​ $ 9.64 ​ $ 10.00 ​ $ 14.85 ​ ​ We determine expected volatility based on a combination of historical volatility using daily price observations and implied volatility from traded options on our common stock. We believe that incorporating both historical and implied volatility into our expected volatility assumption calculation better reflects market expectations. The expected term represents the period of time that options granted are expected to be outstanding. We determine expected term using historical exercise and employee termination data. The risk-free rate for periods within the expected term of the option is based on the U.S. Treasury risk-free interest rate in effect at the time of grant. The dividend yield is based on historical dividend distributions compared to the closing price of our common shares on the grant date. As of December 31, 2020, we had $2.1 million of total unrecognized compensation cost related to nonvested stock options. The cost is expected to be recognized over a weighted-average service period of approximately 1.9 years. Cash received from stock options exercised under these share-based payment arrangements during 2020, 2019 and 2018 was $4.4 million, $3.4 million and $29.0 million, respectively. The actual tax benefits realized for the tax deductions for options exercised under these share-based payment arrangements during 2020, 2019 and 2018 was $1.4 million, $0.5 million and $3.9 million, respectively. Performance Share Awards We granted performance share awards to certain employees under the 2014 Stock Incentive Plan and the Amended and Restated 2010 Stock Incentive Plan. The performance share awards are treated as an equity award and are paid in shares. Whether the performance shares are earned depends upon the participant's continued employment through the performance period (except in the case of specific types of terminations) and our performance against three The following is a summary of activity for the nonvested performance share awards: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Weighted- ​ ​ performance ​ average grant-date ​ share awards fair value ​ ​ (in millions) ​ ​ ​ Nonvested performance share awards as of January 1, 2020 0.5 ​ $ 59.26 ​ Granted ​ 0.3 ​ ​ 51.73 ​ Vested ​ 0.1 ​ ​ 62.78 ​ Nonvested performance share awards as of December 31, 2020 ​ 0.7 ​ $ 55.28 ​ ​ The total intrinsic value of performance share awards vested was $8.7 million, $17.6 million and $21.5 million during 2020, 2019 and 2018, respectively. ​ Performance share awards above represent initial target awards and do not reflect potential increases or decreases resulting from the final performance results to be determined at the end of the respective performance period. The actual number of common shares to be awarded at the end of each performance period will range between 0% and 150% of the initial target awards. The fair value of performance share awards is determined based on the closing stock price of our common shares on the grant date. The weighted-average grant-date fair value of performance share awards granted during 2020, 2019 and 2018 was $51.73, $53.09 and $63.98, respectively. As of December 31, 2020, we had $3.0 million of total unrecognized compensation cost related to nonvested performance share awards granted. The cost is expected to be recognized over a weighted-average service period of approximately 1.9 years. Actual tax benefits realized for the tax deductions for performance share awards paid out under these share-based payment arrangements for 2020, 2019 and 2018 was $3.0 million, $3.3 million and $3.3 million, respectively. Restricted Stock Units We issue restricted stock units under the 2020 Directors Stock Plan, 2014 Stock Incentive Plan, the 2014 Directors Stock Plan, the Amended and Restated 2010 Stock Incentive Plan, the 2005 Directors Stock Plan, the Stock Incentive Plan, and the Directors Stock Plan. Restricted stock units are treated as an equity award and are paid in shares. These awards have no maximum contractual term. Dividend equivalents are credited on restricted stock units outstanding as of the record date. These dividend equivalents are only paid on the shares released. Restricted stock units granted were 1.1 million, 1.1 million and 0.8 million in 2020, 2019 and 2018, respectively. Restricted stock units were issued to certain employees and agents pursuant to the 2014 Stock Incentive Plan, the Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan. Under these plans, awards have graded or cliff vesting over a three Pursuant to the 2020 Directors Stock Plan, 2014 Directors Stock Plan and the 2005 Directors Stock Plan, restricted stock units are granted to each non-employee director in office immediately following each annual meeting of stockholders and, at the discretion of the Nominating and Governance Committee, to each person who becomes a member of the Board other than on the date of the annual meeting of stockholders. Under these plans, awards are granted on an annual basis and cliff vest after a one The following is a summary of activity for the nonvested restricted stock units: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Weighted- ​ ​ restricted ​ average grant-date ​ stock units fair value ​ ​ (in millions) ​ ​ ​ Nonvested restricted stock units as of January 1, 2020 2.6 ​ $ 59.15 ​ Granted ​ 1.1 ​ ​ 50.49 ​ Vested ​ 0.8 ​ ​ 62.32 ​ Canceled ​ 0.1 ​ ​ 55.68 ​ Nonvested restricted stock units as of December 31, 2020 ​ 2.8 ​ $ 54.86 ​ ​ The total intrinsic value of restricted stock units vested was $41.2 million, $64.0 million and $51.1 during 2020, 2019 and 2018, respectively. The fair value of restricted stock units is determined based on the closing stock price of our common shares on the grant date. The weighted-average grant-date fair value of restricted stock units granted during 2020, 2019 and 2018 was $50.49, $53.17 and $63.68, respectively. As of December 31, 2020, we had $43.4 million of total unrecognized compensation cost related to nonvested restricted stock unit awards granted under these plans. The cost is expected to be recognized over a weighted-average period of approximately 1.7 years. The actual tax benefits realized for the tax deductions for restricted stock unit payouts under these share-based payment arrangements for 2020, 2019 and 2018 was $14.6 million, $13.2 million and $10.8 million, respectively. Employee Stock Purchase Plan Under our Employee Stock Purchase Plan, participating employees had the opportunity to purchase shares of our common stock on a semi-annual basis through 2017. Beginning in 2018, participating employees had the opportunity to purchase shares of our common stock on a quarterly basis. Employees may purchase up to $25,000 in stock value annually. Employees may purchase shares of our common stock at a price equal to 85% of the shares' fair market value as of the beginning or end of the purchase period, whichever is lower. Under the Employee Stock Purchase Plan, employees purchased 1.4 million, 0.9 million and 0.7 million shares during 2020, 2019 and 2018, respectively. We recognize compensation expense for the fair value of the discount granted to employees participating in the employee stock purchase plan in the period of grant. Shares of the Employee Stock Purchase Plan are treated as an equity award. The weighted-average fair value of the discount on the stock purchased was $11.33, $11.37 and $9.27 during 2020, 2019 and 2018, respectively. The total intrinsic value of the Employee Stock Purchase Plan shares settled was $15.5 million, $9.7 million and $6.1 million during 2020, 2019 and 2018, respectively. Cash received from shares issued under these share-based payment arrangements for 2020, 2019 and 2018 was $37.8 million, $36.2 million and $30.1 million, respectively. The actual tax benefit realized for the tax deductions for the settlement of the share-based payment arrangements for 2020, 2019 and 2018 was $0.9 million, $0.9 million and $0.7 million, respectively. As of December 31, 2020, a total of 5.0 million of new shares were available to be made issuable by us for this plan.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Common Share
Earnings Per Common Share	19. Earnings Per Common Share The computations of the basic and diluted per share amounts were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions, except per share data) Net income ​ $ 1,428.5 ​ $ 1,444.1 ​ $ 1,553.7 ​ Subtract: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to noncontrolling interest ​ ​ 32.7 ​ 49.9 ​ 7.2 ​ Total ​ $ 1,395.8 ​ $ 1,394.2 ​ $ 1,546.5 ​ Weighted-average shares outstanding: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ ​ 274.7 ​ 278.6 ​ 285.8 ​ Dilutive effects: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options ​ ​ 0.3 ​ 0.9 ​ 1.0 ​ Restricted stock units ​ ​ 1.5 ​ 1.4 ​ 1.7 ​ Performance share awards ​ ​ 0.1 ​ 0.1 ​ 0.3 ​ Diluted ​ ​ 276.6 ​ 281.0 ​ 288.8 ​ Net income per common share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ $ 5.08 ​ $ 5.00 ​ $ 5.41 ​ Diluted ​ $ 5.05 ​ $ 4.96 ​ $ 5.36 ​ ​ The calculation of diluted earnings per share for the years ended December 31, 2020, 2019 and 2018, excludes the incremental effect related to certain outstanding stock-based compensation grants due to their anti-dilutive effect.

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Results of Operations (Unaudited)
Quarterly Results of Operations (Unaudited)	20. Quarterly Results of Operations (Unaudited) The following is a summary of unaudited quarterly results of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three months ended , ​ December 31 September 30 June 30 March 31 ​ ​ (in millions, except per share data) 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 3,765.1 ​ $ 3,310.7 ​ $ 3,114.6 ​ $ 4,551.3 ​ Total expenses ​ ​ 3,173.5 ​ 3,035.6 ​ 2,616.0 ​ 4,223.1 ​ Net income ​ ​ 491.5 ​ 235.9 ​ 416.1 ​ 285.0 ​ Net income attributable to PFG ​ ​ 472.6 ​ 236.0 ​ 398.3 ​ 288.9 ​ Basic earnings per common share ​ ​ 1.72 ​ 0.86 ​ 1.45 ​ 1.05 ​ Diluted earnings per common share ​ ​ 1.70 ​ 0.85 ​ 1.45 ​ 1.04 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 4,047.2 ​ $ 4,458.4 ​ $ 3,972.6 ​ $ 3,743.9 ​ Total expenses ​ ​ 3,675.9 ​ 4,112.7 ​ 3,522.3 ​ 3,217.9 ​ Net income ​ ​ 315.3 ​ 284.6 ​ 392.1 ​ 452.1 ​ Net income attributable to PFG ​ ​ 300.9 ​ 277.1 ​ 386.3 ​ 429.9 ​ Basic earnings per common share ​ ​ 1.08 ​ 0.99 ​ 1.38 ​ 1.54 ​ Diluted earnings per common share ​ ​ 1.07 ​ 0.98 ​ 1.37 ​ 1.53 ​ ​

Condensed Consolidating Financi

Condensed Consolidating Financial Information	12 Months Ended
	Dec. 31, 2020
Condensed Consolidating Financial Information
Condensed Consolidating Financial Information	21. Condensed Consolidating Financial Information Principal Life had established special purpose entities to issue secured medium-term notes. Under the program, the payment obligations of principal and interest on the notes were secured by funding agreements issued by Principal Life. Both the notes and supporting funding agreements were registered with the SEC. Principal Life’s payment obligations on the funding agreements were fully and unconditionally guaranteed by PFG. All of the outstanding stock of Principal Life is indirectly owned by PFG and PFG was the only guarantor of the payment obligations of the funding agreements. As of April 2020, there were no outstanding funding agreements or medium-term notes associated with this program. Under our current shelf registration that was filed with the SEC and became effective April 29, 2020, we have the ability to issue, in unlimited amounts, unsecured senior debt securities or subordinated debt securities, junior subordinated debt, preferred stock, common stock, warrants, depositary shares, purchase contracts and purchase units of PFG. Our wholly owned subsidiary, PFS, may guarantee, fully and unconditionally or otherwise, our obligations with respect to any non-convertible securities, other than common stock, described in the shelf registration. The following tables set forth condensed consolidating financial information of (i) PFG, (ii) PFS, (iii) Principal Life and all other direct and indirect subsidiaries of PFG on a combined basis and (iv) the eliminations necessary to arrive at the information for PFG on a consolidated basis as of December 31, 2020 and December 31, 2019, and for the years ended December 31, 2020, 2019 and 2018. In presenting the condensed consolidating financial statements, the equity method of accounting has been applied to (i) PFG’s interest in all direct subsidiaries of PFG and (ii) PFS’s interest in Principal Life and all other subsidiaries, where applicable, even though all such subsidiaries meet the requirements to be consolidated under U.S. GAAP. Earnings of subsidiaries are, therefore, reflected in the parent’s investment and earnings. All intercompany balances and transactions, including elimination of the parent’s investment in subsidiaries, between PFG, PFS and Principal Life and all other subsidiaries have been eliminated, as shown in the column “Eliminations.” These condensed consolidating financial statements should be read in conjunction with the consolidated financial statements. The financial information may not necessarily be indicative of results of operations, cash flows or financial position had the subsidiaries operated as independent entities. PFG sponsors nonqualified benefit plans for select employees and agents and is responsible for the obligations of these plans. Nonqualified plan assets are held in Rabbi trusts for the benefit of all nonqualified plan participants. The Rabbi trusts are separate legal entities and are not a part of PFG on a stand-alone basis. The plan assets are available to satisfy the claims of general creditors only in the event of bankruptcy and are, therefore, consolidated in our statements of financial position. ​ Condensed Consolidating Statements of Financial Position December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ $ 813.2 ​ $ — ​ $ 77,897.1 ​ $ — ​ $ 78,710.3 ​ Fixed maturities, trading ​ 178.8 ​ ​ — ​ ​ 353.3 ​ ​ — ​ ​ 532.1 ​ Equity securities ​ — ​ ​ 42.9 ​ ​ 1,970.5 ​ ​ — ​ ​ 2,013.4 ​ Mortgage loans ​ — ​ ​ — ​ ​ 17,343.0 ​ ​ — ​ ​ 17,343.0 ​ Real estate ​ — ​ ​ — ​ ​ 1,797.3 ​ ​ — ​ ​ 1,797.3 ​ Policy loans ​ — ​ ​ — ​ ​ 784.0 ​ ​ — ​ ​ 784.0 ​ Investment in unconsolidated entities ​ 19,714.3 ​ ​ 18,557.9 ​ ​ 615.9 ​ ​ (38,045.4) ​ ​ 842.7 ​ Other investments ​ 63.7 ​ ​ 156.3 ​ ​ 4,064.1 ​ ​ — ​ ​ 4,284.1 ​ Cash and cash equivalents ​ 302.4 ​ ​ 819.1 ​ ​ 2,740.7 ​ ​ (1,012.4) ​ ​ 2,849.8 ​ Accrued investment income ​ 2.3 ​ ​ 0.2 ​ ​ 708.1 ​ ​ — ​ ​ 710.6 ​ Premiums due and other receivables ​ — ​ ​ 88.8 ​ ​ 1,910.2 ​ ​ (275.2) ​ ​ 1,723.8 ​ Deferred acquisition costs ​ — ​ ​ — ​ ​ 3,409.7 ​ ​ — ​ ​ 3,409.7 ​ Property and equipment ​ — ​ ​ — ​ ​ 1,019.0 ​ ​ — ​ ​ 1,019.0 ​ Goodwill ​ — ​ ​ 618.5 ​ ​ 1,092.5 ​ ​ — ​ ​ 1,711.0 ​ Other intangibles ​ — ​ ​ 503.6 ​ ​ 1,219.4 ​ ​ — ​ ​ 1,723.0 ​ Separate account assets ​ — ​ ​ — ​ ​ 175,951.4 ​ ​ — ​ ​ 175,951.4 ​ Other assets ​ 408.1 ​ ​ 58.0 ​ ​ 1,362.7 ​ ​ (606.3) ​ ​ 1,222.5 ​ Total assets ​ $ 21,482.8 ​ $ 20,845.3 ​ $ 294,238.9 ​ $ (39,939.3) ​ $ 296,627.7 ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractholder funds ​ $ — ​ $ — ​ $ 43,237.7 ​ $ — ​ $ 43,237.7 ​ Future policy benefits and claims ​ — ​ ​ — ​ ​ 45,207.2 ​ ​ — ​ ​ 45,207.2 ​ Other policyholder funds ​ — ​ ​ — ​ ​ 1,059.4 ​ ​ — ​ ​ 1,059.4 ​ Short-term debt ​ — ​ ​ — ​ ​ 84.7 ​ ​ — ​ ​ 84.7 ​ Long-term debt ​ 4,223.3 ​ ​ 274.9 ​ ​ 55.9 ​ ​ (274.9) ​ ​ 4,279.2 ​ Income taxes currently payable ​ — ​ ​ — ​ ​ 79.7 ​ ​ (57.4) ​ ​ 22.3 ​ Deferred income taxes ​ — ​ ​ 31.3 ​ ​ 2,824.4 ​ ​ (524.9) ​ ​ 2,330.8 ​ Separate account liabilities ​ — ​ ​ — ​ ​ 175,951.4 ​ ​ — ​ ​ 175,951.4 ​ Other liabilities ​ 700.6 ​ ​ 973.2 ​ ​ 6,769.6 ​ ​ (861.3) ​ ​ 7,582.1 ​ Total liabilities ​ 4,923.9 ​ ​ 1,279.4 ​ ​ 275,270.0 ​ ​ (1,718.5) ​ ​ 279,754.8 ​ Redeemable noncontrolling interest ​ — ​ ​ — ​ ​ 255.6 ​ ​ — ​ ​ 255.6 ​ Stockholders' equity ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common stock ​ 4.8 ​ ​ — ​ ​ 5.5 ​ ​ (5.5) ​ ​ 4.8 ​ Additional paid-in capital ​ 10,321.6 ​ ​ 9,738.4 ​ ​ 12,357.7 ​ ​ (22,096.1) ​ ​ 10,321.6 ​ Retained earnings ​ 11,838.0 ​ ​ 6,980.7 ​ ​ 3,285.9 ​ ​ (10,266.6) ​ ​ 11,838.0 ​ Accumulated other comprehensive income ​ 2,383.1 ​ ​ 2,846.8 ​ ​ 3,005.8 ​ ​ (5,852.6) ​ ​ 2,383.1 ​ Treasury stock, at cost ​ (7,988.6) ​ ​ — ​ ​ — ​ ​ — ​ ​ (7,988.6) ​ Total stockholders' equity attributable to PFG ​ 16,558.9 ​ ​ 19,565.9 ​ ​ 18,654.9 ​ ​ (38,220.8) ​ ​ 16,558.9 ​ Noncontrolling interest ​ — ​ ​ — ​ ​ 58.4 ​ ​ — ​ ​ 58.4 ​ Total stockholders’ equity ​ 16,558.9 ​ ​ 19,565.9 ​ ​ 18,713.3 ​ ​ (38,220.8) ​ ​ 16,617.3 ​ Total liabilities and stockholders' equity ​ $ 21,482.8 ​ $ 20,845.3 ​ $ 294,238.9 ​ $ (39,939.3) ​ $ 296,627.7 ​ (1) PFG sponsors nonqualified benefit plans. Nonqualified benefit plan assets and liabilities held in Rabbi trusts were $801.7 million and $653.3 million, respectively. ​ ​ Condensed Consolidating Statements of Financial Position December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ $ 265.8 ​ $ — ​ $ 69,840.4 ​ $ — ​ $ 70,106.2 ​ Fixed maturities, trading ​ 268.2 ​ ​ — ​ ​ 407.7 ​ ​ — ​ ​ 675.9 ​ Equity securities ​ — ​ ​ 41.4 ​ ​ 1,838.0 ​ ​ — ​ ​ 1,879.4 ​ Mortgage loans ​ — ​ ​ — ​ ​ 16,486.9 ​ ​ — ​ ​ 16,486.9 ​ Real estate ​ — ​ ​ — ​ ​ 1,714.8 ​ ​ — ​ ​ 1,714.8 ​ Policy loans ​ — ​ ​ — ​ ​ 798.0 ​ ​ — ​ ​ 798.0 ​ Investment in unconsolidated entities ​ 17,539.6 ​ ​ 16,664.1 ​ ​ 649.4 ​ ​ (34,022.9) ​ ​ 830.2 ​ Other investments ​ 10.4 ​ ​ 251.9 ​ ​ 3,597.7 ​ ​ — ​ ​ 3,860.0 ​ Cash and cash equivalents ​ 394.9 ​ ​ 598.4 ​ ​ 2,656.2 ​ ​ (1,133.6) ​ ​ 2,515.9 ​ Accrued investment income ​ 1.6 ​ ​ 0.4 ​ ​ 684.6 ​ ​ — ​ ​ 686.6 ​ Premiums due and other receivables ​ — ​ ​ 100.0 ​ ​ 1,961.1 ​ ​ (320.8) ​ ​ 1,740.3 ​ Deferred acquisition costs ​ — ​ ​ — ​ ​ 3,521.3 ​ ​ — ​ ​ 3,521.3 ​ Property and equipment ​ — ​ ​ — ​ ​ 967.7 ​ ​ — ​ ​ 967.7 ​ Goodwill ​ — ​ ​ 618.5 ​ ​ 1,075.3 ​ ​ — ​ ​ 1,693.8 ​ Other intangibles ​ — ​ ​ 531.7 ​ ​ 1,255.0 ​ ​ — ​ ​ 1,786.7 ​ Separate account assets ​ — ​ ​ — ​ ​ 165,468.0 ​ ​ — ​ ​ 165,468.0 ​ Other assets ​ 383.2 ​ ​ 35.2 ​ ​ 1,509.5 ​ ​ (571.8) ​ ​ 1,356.1 ​ Total assets ​ $ 18,863.7 ​ $ 18,841.6 ​ $ 274,431.6 ​ $ (36,049.1) ​ $ 276,087.8 ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractholder funds ​ $ — ​ $ — ​ $ 41,367.5 ​ $ — ​ $ 41,367.5 ​ Future policy benefits and claims ​ — ​ ​ — ​ ​ 40,838.2 ​ ​ — ​ ​ 40,838.2 ​ Other policyholder funds ​ — ​ ​ — ​ ​ 959.4 ​ ​ — ​ ​ 959.4 ​ Short-term debt ​ — ​ ​ — ​ ​ 93.4 ​ ​ — ​ ​ 93.4 ​ Long-term debt ​ 3,625.5 ​ ​ 320.7 ​ ​ 108.7 ​ ​ (320.8) ​ ​ 3,734.1 ​ Income taxes currently payable ​ — ​ ​ — ​ ​ 66.4 ​ ​ (50.2) ​ ​ 16.2 ​ Deferred income taxes ​ — ​ ​ 5.9 ​ ​ 2,285.8 ​ ​ (495.1) ​ ​ 1,796.6 ​ Separate account liabilities ​ — ​ ​ — ​ ​ 165,468.0 ​ ​ — ​ ​ 165,468.0 ​ Other liabilities ​ 620.2 ​ ​ 1,113.6 ​ ​ 6,104.7 ​ ​ (974.8) ​ ​ 6,863.7 ​ Total liabilities ​ 4,245.7 ​ ​ 1,440.2 ​ ​ 257,292.1 ​ ​ (1,840.9) ​ ​ 261,137.1 ​ Redeemable noncontrolling interest ​ — ​ ​ — ​ ​ 264.9 ​ ​ — ​ ​ 264.9 ​ Stockholders' equity ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common stock ​ 4.8 ​ ​ — ​ ​ 11.0 ​ ​ (11.0) ​ ​ 4.8 ​ Additional paid-in capital ​ 10,182.6 ​ ​ 9,658.3 ​ ​ 12,157.9 ​ ​ (21,816.2) ​ ​ 10,182.6 ​ Retained earnings ​ 11,074.3 ​ ​ 6,263.5 ​ ​ 2,985.1 ​ ​ (9,248.6) ​ ​ 11,074.3 ​ Accumulated other comprehensive income ​ 1,037.9 ​ ​ 1,479.6 ​ ​ 1,654.8 ​ ​ (3,134.4) ​ ​ 1,037.9 ​ Treasury stock, at cost ​ (7,681.6) ​ ​ — ​ ​ (2.0) ​ ​ 2.0 ​ ​ (7,681.6) ​ Total stockholders' equity attributable to PFG ​ 14,618.0 ​ ​ 17,401.4 ​ ​ 16,806.8 ​ ​ (34,208.2) ​ ​ 14,618.0 ​ Noncontrolling interest ​ — ​ ​ — ​ ​ 67.8 ​ ​ — ​ ​ 67.8 ​ Total stockholders’ equity ​ 14,618.0 ​ ​ 17,401.4 ​ ​ 16,874.6 ​ ​ (34,208.2) ​ ​ 14,685.8 ​ Total liabilities and stockholders' equity ​ $ 18,863.7 ​ $ 18,841.6 ​ $ 274,431.6 ​ $ (36,049.1) ​ $ 276,087.8 ​ (1) PFG sponsors nonqualified benefit plans. Nonqualified benefit plan assets and liabilities held in Rabbi trusts were $731.9 million and $593.7 million, respectively. ​ Condensed Consolidating Statements of Operations For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ — ​ $ — ​ $ 6,037.4 ​ $ — ​ $ 6,037.4 ​ Fees and other revenues ​ — ​ ​ 341.3 ​ ​ 4,182.9 ​ ​ (13.1) ​ ​ 4,511.1 ​ Net investment income (loss) ​ 13.3 ​ ​ (1.4) ​ ​ 3,867.1 ​ ​ 11.6 ​ ​ 3,890.6 ​ Net realized capital gains ​ 7.0 ​ ​ 32.8 ​ ​ 262.9 ​ ​ (0.1) ​ ​ 302.6 ​ Total revenues ​ 20.3 ​ ​ 372.7 ​ ​ 14,350.3 ​ ​ (1.6) ​ ​ 14,741.7 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ — ​ ​ — ​ ​ 8,281.5 ​ ​ — ​ ​ 8,281.5 ​ Dividends to policyholders ​ — ​ ​ — ​ ​ 120.2 ​ ​ — ​ ​ 120.2 ​ Operating expenses ​ 200.0 ​ ​ 548.7 ​ ​ 3,909.6 ​ ​ (11.8) ​ ​ 4,646.5 ​ Total expenses ​ 200.0 ​ ​ 548.7 ​ ​ 12,311.3 ​ ​ (11.8) ​ ​ 13,048.2 ​ Income (loss) before income taxes ​ (179.7) ​ ​ (176.0) ​ ​ 2,039.0 ​ ​ 10.2 ​ ​ 1,693.5 ​ Income taxes (benefits) ​ (46.1) ​ ​ (45.8) ​ ​ 356.9 ​ ​ — ​ ​ 265.0 ​ Equity in the net income of subsidiaries ​ 1,529.4 ​ ​ 1,649.4 ​ ​ — ​ ​ (3,178.8) ​ ​ — ​ Net income ​ 1,395.8 ​ ​ 1,519.2 ​ ​ 1,682.1 ​ ​ (3,168.6) ​ ​ 1,428.5 ​ Net income attributable to noncontrolling interest ​ — ​ ​ — ​ ​ 32.7 ​ ​ — ​ ​ 32.7 ​ Net income attributable to PFG ​ $ 1,395.8 ​ $ 1,519.2 ​ $ 1,649.4 ​ $ (3,168.6) ​ $ 1,395.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,395.8 ​ $ 1,519.2 ​ $ 1,682.1 ​ $ (3,168.6) ​ $ 1,428.5 ​ Other comprehensive income ​ 1,206.5 ​ ​ 1,228.6 ​ ​ 1,352.7 ​ ​ (2,440.8) ​ ​ 1,347.0 ​ Comprehensive income ​ $ 2,602.3 ​ $ 2,747.8 ​ $ 3,034.8 ​ $ (5,609.4) ​ $ 2,775.5 ​ ​ ​ Condensed Consolidating Statements of Operations For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ — ​ $ — ​ $ 7,866.6 ​ $ — ​ $ 7,866.6 ​ Fees and other revenues ​ — ​ ​ 205.9 ​ ​ 4,215.5 ​ ​ (11.5) ​ ​ 4,409.9 ​ Net investment income (loss) ​ 19.4 ​ ​ (6.5) ​ ​ 3,975.1 ​ ​ 10.4 ​ ​ 3,998.4 ​ Net realized capital gains (losses), excluding impairment losses on available-for-sale securities ​ 12.3 ​ ​ 17.5 ​ ​ (38.9) ​ ​ (0.2) ​ ​ (9.3) ​ Net other-than-temporary impairment losses on available-for-sale securities ​ — ​ ​ — ​ ​ (38.3) ​ ​ — ​ ​ (38.3) ​ Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income ​ — ​ ​ — ​ ​ (5.2) ​ ​ — ​ ​ (5.2) ​ Net impairment losses on available-for-sale securities ​ — ​ ​ — ​ ​ (43.5) ​ ​ — ​ ​ (43.5) ​ Net realized capital gains (losses) ​ 12.3 ​ ​ 17.5 ​ ​ (82.4) ​ ​ (0.2) ​ ​ (52.8) ​ Total revenues ​ 31.7 ​ ​ 216.9 ​ ​ 15,974.8 ​ ​ (1.3) ​ ​ 16,222.1 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ — ​ ​ — ​ ​ 9,905.8 ​ ​ — ​ ​ 9,905.8 ​ Dividends to policyholders ​ — ​ ​ — ​ ​ 119.1 ​ ​ — ​ ​ 119.1 ​ Operating expenses ​ 210.9 ​ ​ 368.2 ​ ​ 3,935.1 ​ ​ (10.3) ​ ​ 4,503.9 ​ Total expenses ​ 210.9 ​ ​ 368.2 ​ ​ 13,960.0 ​ ​ (10.3) ​ ​ 14,528.8 ​ Income (loss) before income taxes ​ (179.2) ​ ​ (151.3) ​ ​ 2,014.8 ​ ​ 9.0 ​ ​ 1,693.3 ​ Income taxes (benefits) ​ (44.2) ​ ​ (11.8) ​ ​ 305.2 ​ ​ — ​ ​ 249.2 ​ Equity in the net income of subsidiaries ​ 1,529.2 ​ ​ 1,659.7 ​ ​ — ​ ​ (3,188.9) ​ ​ — ​ Net income ​ 1,394.2 ​ ​ 1,520.2 ​ ​ 1,709.6 ​ ​ (3,179.9) ​ ​ 1,444.1 ​ Net income attributable to noncontrolling interest ​ — ​ ​ — ​ ​ 49.9 ​ ​ — ​ ​ 49.9 ​ Net income attributable to PFG ​ $ 1,394.2 ​ $ 1,520.2 ​ $ 1,659.7 ​ $ (3,179.9) ​ $ 1,394.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,394.2 ​ $ 1,520.2 ​ $ 1,709.6 ​ $ (3,179.9) ​ $ 1,444.1 ​ Other comprehensive income ​ 2,570.9 ​ ​ 2,530.9 ​ ​ 2,562.2 ​ ​ (5,057.3) ​ ​ 2,606.7 ​ Comprehensive income ​ $ 3,965.1 ​ $ 4,051.1 ​ $ 4,271.8 ​ $ (8,237.2) ​ $ 4,050.8 ​ ​ ​ Condensed Consolidating Statements of Operations For the year ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ — ​ $ — ​ $ 6,409.6 ​ $ — ​ $ 6,409.6 ​ Fees and other revenues ​ — ​ 2.7 ​ 4,286.4 ​ (15.3) ​ 4,273.8 ​ Net investment income (loss) ​ 25.8 ​ (6.7) ​ 3,598.0 ​ 12.1 ​ 3,629.2 ​ Net realized capital losses, excluding impairment losses on available-for-sale securities ​ (8.2) ​ (3.5) ​ (34.6) ​ — ​ (46.3) ​ Net other-than-temporary impairment recoveries on available-for-sale securities ​ — ​ — ​ 10.6 ​ — ​ 10.6 ​ Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income ​ — ​ — ​ (39.7) ​ — ​ (39.7) ​ Net impairment losses on available-for-sale securities ​ — ​ — ​ (29.1) ​ — ​ (29.1) ​ Net realized capital losses ​ (8.2) ​ (3.5) ​ (63.7) ​ — ​ (75.4) ​ Total revenues ​ 17.6 ​ (7.5) ​ 14,230.3 ​ (3.2) ​ 14,237.2 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ — ​ — ​ 8,192.5 ​ — ​ 8,192.5 ​ Dividends to policyholders ​ — ​ — ​ 123.6 ​ — ​ 123.6 ​ Operating expenses ​ 191.9 ​ 29.1 ​ 3,929.5 ​ (13.8) ​ 4,136.7 ​ Total expenses ​ 191.9 ​ 29.1 ​ 12,245.6 ​ (13.8) ​ 12,452.8 ​ Income (loss) before income taxes ​ (174.3) ​ (36.6) ​ 1,984.7 ​ 10.6 ​ 1,784.4 ​ Income taxes (benefits) ​ (62.5) ​ 0.2 ​ 293.0 ​ — ​ 230.7 ​ Equity in the net income of subsidiaries ​ 1,658.3 ​ 1,684.5 ​ — ​ (3,342.8) ​ — ​ Net income ​ ​ 1,546.5 ​ ​ 1,647.7 ​ ​ 1,691.7 ​ (3,332.2) ​ 1,553.7 ​ Net income attributable to noncontrolling interest ​ — ​ — ​ 7.2 ​ — ​ 7.2 ​ Net income attributable to PFG ​ $ 1,546.5 ​ $ 1,647.7 ​ $ 1,684.5 ​ $ (3,332.2) ​ $ 1,546.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,546.5 ​ $ 1,647.7 ​ $ 1,691.7 ​ $ (3,332.2) ​ $ 1,553.7 ​ Other comprehensive loss ​ (1,824.5) ​ ​ (1,839.1) ​ ​ (1,856.4) ​ ​ 3,684.3 ​ ​ (1,835.7) ​ Comprehensive loss ​ $ (278.0) ​ $ (191.4) ​ $ (164.7) ​ $ 352.1 ​ $ (282.0) ​ ​ ​ Condensed Consolidating Statements of Cash Flows For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) operating activities ​ $ (15.2) ​ $ 1,490.5 ​ $ 4,014.8 ​ $ (1,751.5) ​ $ 3,738.6 ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ ​ (736.5) ​ ​ — ​ ​ (14,976.9) ​ ​ — ​ ​ (15,713.4) ​ Sales ​ ​ — ​ ​ — ​ ​ 3,043.9 ​ ​ — ​ ​ 3,043.9 ​ Maturities ​ ​ 193.7 ​ ​ — ​ ​ 8,625.8 ​ ​ — ​ ​ 8,819.5 ​ Mortgage loans acquired or originated ​ ​ — ​ ​ — ​ ​ (3,249.5) ​ ​ — ​ ​ (3,249.5) ​ Mortgage loans sold or repaid ​ ​ — ​ ​ — ​ ​ 2,477.2 ​ ​ — ​ ​ 2,477.2 ​ Real estate acquired ​ ​ — ​ ​ — ​ ​ (230.6) ​ ​ — ​ ​ (230.6) ​ Real estate sold ​ ​ — ​ ​ — ​ ​ 2.3 ​ ​ — ​ ​ 2.3 ​ Net purchases of property and equipment ​ ​ (0.1) ​ ​ (3.5) ​ ​ (105.2) ​ ​ — ​ ​ (108.8) ​ Dividends and returns of capital received from unconsolidated entities ​ ​ 799.1 ​ ​ 1,189.2 ​ ​ — ​ ​ (1,988.3) ​ ​ — ​ Net change in other investments ​ ​ (50.0) ​ ​ (1,610.4) ​ ​ (232.7) ​ ​ 1,826.7 ​ ​ (66.4) ​ Net cash provided by (used in) investing activities ​ ​ 206.2 ​ ​ (424.7) ​ ​ (4,645.7) ​ ​ (161.6) ​ ​ (5,025.8) ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ ​ 42.8 ​ ​ — ​ ​ — ​ ​ — ​ ​ 42.8 ​ Acquisition of treasury stock ​ ​ (307.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ (307.0) ​ Payments for financing element derivatives ​ ​ — ​ ​ — ​ ​ (30.9) ​ ​ — ​ ​ (30.9) ​ Purchase of subsidiary shares from noncontrolling interest ​ ​ — ​ ​ — ​ ​ (1.4) ​ ​ — ​ ​ (1.4) ​ Dividends to common stockholders ​ ​ (614.5) ​ ​ — ​ ​ — ​ ​ — ​ ​ (614.5) ​ Issuance of long-term debt ​ ​ 595.2 ​ ​ 8.5 ​ ​ 13.7 ​ ​ (8.5) ​ ​ 608.9 ​ Principal repayments of long-term debt ​ ​ — ​ ​ (54.5) ​ ​ (65.8) ​ ​ 54.5 ​ ​ (65.8) ​ Net repayments of short-term borrowings ​ ​ — ​ ​ — ​ ​ (12.6) ​ ​ — ​ ​ (12.6) ​ Dividends and capital paid to parent ​ ​ — ​ ​ (799.1) ​ ​ (1,189.2) ​ ​ 1,988.3 ​ ​ — ​ Investment contract deposits ​ ​ — ​ ​ — ​ ​ 10,284.4 ​ ​ — ​ ​ 10,284.4 ​ Investment contract withdrawals ​ ​ — ​ ​ — ​ ​ (8,852.7) ​ ​ — ​ ​ (8,852.7) ​ Net increase in banking operation deposits ​ ​ — ​ ​ — ​ ​ 569.7 ​ ​ — ​ ​ 569.7 ​ Other ​ ​ — ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ 0.2 ​ Net cash provided by (used in) financing activities ​ ​ (283.5) ​ ​ (845.1) ​ ​ 715.4 ​ ​ 2,034.3 ​ ​ 1,621.1 ​ Net increase (decrease) in cash and cash equivalents ​ ​ (92.5) ​ ​ 220.7 ​ ​ 84.5 ​ ​ 121.2 ​ ​ 333.9 ​ Cash and cash equivalents at beginning of period ​ 394.9 ​ ​ 598.4 ​ ​ 2,656.2 ​ ​ (1,133.6) ​ ​ 2,515.9 ​ Cash and cash equivalents at end of period ​ $ 302.4 ​ $ 819.1 ​ $ 2,740.7 ​ $ (1,012.4) ​ $ 2,849.8 ​ ​ ​ Condensed Consolidating Statements of Cash Flows For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) operating activities ​ $ 7.1 ​ $ (54.7) ​ $ 5,760.7 ​ $ (219.9) ​ $ 5,493.2 ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ ​ (251.5) ​ ​ (0.2) ​ ​ (13,885.4) ​ ​ — ​ ​ (14,137.1) ​ Sales ​ ​ — ​ ​ 0.2 ​ ​ 2,397.2 ​ ​ — ​ ​ 2,397.4 ​ Maturities ​ ​ 200.0 ​ ​ — ​ ​ 6,864.2 ​ ​ — ​ ​ 7,064.2 ​ Mortgage loans acquired or originated ​ ​ — ​ ​ — ​ ​ (3,487.7) ​ ​ — ​ ​ (3,487.7) ​ Mortgage loans sold or repaid ​ ​ — ​ ​ — ​ ​ 2,335.9 ​ ​ — ​ ​ 2,335.9 ​ Real estate acquired ​ ​ — ​ ​ — ​ ​ (127.5) ​ ​ — ​ ​ (127.5) ​ Real estate sold ​ ​ — ​ ​ — ​ ​ 96.3 ​ ​ — ​ ​ 96.3 ​ Net purchases of property and equipment ​ ​ (0.1) ​ ​ (2.0) ​ ​ (130.3) ​ ​ — ​ ​ (132.4) ​ Purchase of business or interests in subsidiaries, net of cash acquired ​ ​ — ​ ​ (1,209.6) ​ ​ 1.1 ​ ​ — ​ ​ (1,208.5) ​ Dividends and returns of capital received from unconsolidated entities ​ ​ 494.2 ​ ​ 2,118.7 ​ ​ — ​ ​ (2,612.9) ​ ​ — ​ Net change in other investments ​ ​ (34.0) ​ ​ (362.9) ​ ​ (235.8) ​ ​ 143.6 ​ ​ (489.1) ​ Net cash provided by (used in) investing activities ​ ​ 408.6 ​ ​ 544.2 ​ ​ (6,172.0) ​ ​ (2,469.3) ​ ​ (7,688.5) ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ ​ 37.7 ​ ​ — ​ ​ — ​ ​ — ​ ​ 37.7 ​ Acquisition of treasury stock ​ ​ (281.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ (281.0) ​ Payments for financing element derivatives ​ ​ — ​ ​ — ​ ​ (26.9) ​ ​ — ​ ​ (26.9) ​ Purchase of subsidiary shares from noncontrolling interest ​ ​ — ​ ​ — ​ ​ (1.7) ​ ​ — ​ ​ (1.7) ​ Dividends to common stockholders ​ ​ (606.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ (606.0) ​ Issuance of long-term debt ​ ​ 493.6 ​ ​ 10.0 ​ ​ 11.3 ​ ​ (10.0) ​ ​ 504.9 ​ Principal repayments of long-term debt ​ ​ — ​ ​ (55.9) ​ ​ (32.2) ​ ​ 55.9 ​ ​ (32.2) ​ Net proceeds from short-term borrowings ​ ​ — ​ ​ — ​ ​ 57.5 ​ ​ — ​ ​ 57.5 ​ Dividends and capital paid to parent ​ ​ — ​ ​ (494.2) ​ ​ (2,118.7) ​ ​ 2,612.9 ​ ​ — ​ Investment contract deposits ​ ​ — ​ ​ — ​ ​ 9,200.0 ​ ​ — ​ ​ 9,200.0 ​ Investment contract withdrawals ​ ​ — ​ ​ — ​ ​ (7,747.7) ​ ​ — ​ ​ (7,747.7) ​ Net increase in banking operation deposits ​ ​ — ​ ​ — ​ ​ 623.4 ​ ​ — ​ ​ 623.4 ​ Other ​ ​ — ​ ​ — ​ ​ 5.7 ​ ​ — ​ ​ 5.7 ​ Net cash provided by (used in) financing activities ​ ​ (355.7) ​ ​ (540.1) ​ ​ (29.3) ​ ​ 2,658.8 ​ ​ 1,733.7 ​ Net increase (decrease) in cash and cash equivalents ​ ​ 60.0 ​ ​ (50.6) ​ ​ (440.6) ​ ​ (30.4) ​ ​ (461.6) ​ Cash and cash equivalents at beginning of period ​ 334.9 ​ 649.0 ​ 3,096.8 ​ (1,103.2) ​ 2,977.5 ​ Cash and cash equivalents at end of period ​ $ 394.9 ​ $ 598.4 ​ $ 2,656.2 ​ $ (1,133.6) ​ $ 2,515.9 ​ ​ ​ Condensed Consolidating Statements of Cash Flows For the year ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) operating activities ​ $ (132.4) ​ $ 696.3 ​ $ 5,030.9 ​ $ (438.3) ​ $ 5,156.5 ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ (210.9) ​ — ​ (13,698.9) ​ — ​ (13,909.8) ​ Sales ​ — ​ — ​ 3,813.1 ​ — ​ 3,813.1 ​ Maturities ​ 2.3 ​ — ​ 6,215.3 ​ — ​ 6,217.6 ​ Mortgage loans acquired or originated ​ — ​ — ​ (3,447.5) ​ — ​ (3,447.5) ​ Mortgage loans sold or repaid ​ — ​ — ​ 2,228.4 ​ — ​ 2,228.4 ​ Real estate acquired ​ — ​ — ​ (88.1) ​ — ​ (88.1) ​ Real estate sold ​ ​ — ​ ​ — ​ ​ 63.5 ​ ​ — ​ ​ 63.5 ​ Net purchases of property and equipment ​ (0.1) ​ — ​ (92.2) ​ — ​ (92.3) ​ Purchase of business or interests in subsidiaries, net of cash acquired ​ ​ — ​ ​ — ​ ​ (184.7) ​ ​ — ​ ​ (184.7) ​ Dividends and returns of capital received from unconsolidated entities ​ 1,041.6 ​ 589.1 ​ — ​ (1,630.7) ​ — ​ Net change in other investments ​ (2.2) ​ (166.2) ​ (413.9) ​ 279.6 ​ (302.7) ​ Net cash provided by (used in) investing activities ​ 830.7 ​ 422.9 ​ (5,605.0) ​ (1,351.1) ​ (5,702.5) ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ 64.0 ​ — ​ — ​ — ​ 64.0 ​ Acquisition of treasury stock ​ (671.6) ​ — ​ — ​ — ​ (671.6) ​ Payments for financing element derivatives ​ — ​ — ​ (65.9) ​ — ​ (65.9) ​ Purchase of subsidiary shares from noncontrolling interest ​ — ​ — ​ (31.1) ​ — ​ (31.1) ​ Dividends to common stockholders ​ (598.6) ​ — ​ — ​ — ​ (598.6) ​ Issuance of long-term debt ​ — ​ 11.1 ​ 80.8 ​ (11.1) ​ 80.8 ​ Principal repayments of long-term debt ​ — ​ (57.1) ​ (1.3) ​ 57.1 ​ (1.3) ​ Net proceeds from short-term borrowings ​ — ​ — ​ 8.5 ​ — ​ 8.5 ​ Dividends and capital paid to parent ​ — ​ (1,041.6) ​ (589.1) ​ 1,630.7 ​ — ​ Investment contract deposits ​ — ​ — ​ 8,308.8 ​ — ​ 8,308.8 ​ Investment contract withdrawals ​ — ​ — ​ (6,589.6) ​ — ​ (6,589.6) ​ Net increase in banking operation deposits ​ — ​ — ​ 553.0 ​ — ​ 553.0 ​ Other ​ — ​ — ​ (4.3) ​ — ​ (4.3) ​ Net cash provided by (used in) financing activities ​ (1,206.2) ​ (1,087.6) ​ 1,669.8 ​ 1,676.7 ​ 1,052.7 ​ Net increase (decrease) in cash and cash equivalents ​ (507.9) ​ 31.6 ​ 1,095.7 ​ (112.7) ​ 506.7 ​ Cash and cash equivalents at beginning of period ​ 842.8 ​ 617.4 ​ 2,001.1 ​ (990.5) ​ 2,470.8 ​ Cash and cash equivalents at end of period ​ $ 334.9 ​ $ 649.0 ​ $ 3,096.8 ​ $ (1,103.2) ​ $ 2,977.5 ​ ​

Schedule I - Summary of Investm

Schedule I - Summary of Investments - Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2020
Schedule I - Summary of Investments - Other Than Investments in Related Parties
Schedule I - Summary of Investments - Other Than Investments in Related Parties	Schedule I - Summary of Investments - Other Than Investments in Related Parties December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount as ​ ​ ​ ​ ​ ​ ​ ​ shown in the ​ ​ ​ ​ ​ ​ ​ ​ consolidated ​ ​ ​ ​ ​ ​ ​ ​ statement of ​ ​ ​ ​ ​ Fair ​ financial Type of Investment Cost value position ​ ​ (in millions) Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities and obligations of U.S. government corporations and agencies ​ $ 1,893.1 ​ $ 2,111.5 ​ $ 2,111.5 ​ States, municipalities and political subdivisions ​ ​ 8,004.9 ​ ​ 9,167.8 ​ ​ 9,167.8 ​ Foreign governments ​ ​ 881.6 ​ ​ 1,073.7 ​ ​ 1,073.7 ​ Public utilities ​ ​ 5,375.6 ​ ​ 6,114.3 ​ ​ 6,114.3 ​ Redeemable preferred stock ​ ​ 19.3 ​ ​ 20.8 ​ ​ 20.8 ​ All other corporate bonds ​ ​ 35,895.0 ​ ​ 41,219.7 ​ ​ 41,219.7 ​ Residential mortgage-backed pass-through securities ​ ​ 2,857.6 ​ ​ 2,986.8 ​ ​ 2,986.8 ​ Commercial mortgage-backed securities ​ ​ 4,741.2 ​ ​ 4,942.3 ​ ​ 4,942.3 ​ Collateralized debt obligations ​ ​ 4,045.9 ​ ​ 4,027.5 ​ ​ 4,027.5 ​ Other debt obligations ​ ​ 6,832.6 ​ ​ 7,045.9 ​ ​ 7,045.9 ​ Total fixed maturities, available-for-sale ​ ​ 70,546.8 ​ ​ 78,710.3 ​ ​ 78,710.3 ​ Fixed maturities, trading ​ ​ 532.1 ​ ​ 532.1 ​ ​ 532.1 ​ Equity securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Banks, trust and insurance companies ​ ​ 483.4 ​ ​ 483.4 ​ ​ 483.4 ​ Public utilities ​ ​ 6.8 ​ ​ 6.8 ​ ​ 6.8 ​ Industrial, miscellaneous and all other ​ ​ 874.6 ​ ​ 874.6 ​ ​ 874.6 ​ Other corporate ​ ​ 499.7 ​ ​ 499.7 ​ ​ 499.7 ​ Non-redeemable preferred stock ​ ​ 148.9 ​ ​ 148.9 ​ ​ 148.9 ​ Total equity securities ​ ​ 2,013.4 ​ ​ 2,013.4 ​ ​ 2,013.4 ​ Mortgage loans ​ ​ 17,343.0 ​ XXXX ​ ​ 17,343.0 ​ Real estate, net: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate acquired in satisfaction of debt ​ ​ 1.2 ​ XXXX ​ ​ 1.2 ​ Other real estate ​ ​ 1,796.1 ​ XXXX ​ ​ 1,796.1 ​ Policy loans ​ ​ 784.0 ​ XXXX ​ ​ 784.0 ​ Other investments ​ ​ 5,126.8 ​ XXXX ​ ​ 5,126.8 ​ Total investments ​ $ 98,143.4 ​ XXXX ​ $ 106,306.9 ​ ​

Schedule II - Condensed Financi

Schedule II - Condensed Financial Information of Registrant (Parent Only)	12 Months Ended
	Dec. 31, 2020
Schedule II - Condensed Financial Information of Registrant (Parent Only)
Schedule II - Condensed Financial Information of Registrant (Parent Only)	Schedule II - Condensed Financial Information of Registrant (Parent Only) Statements of Financial Position ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ $ 813.2 ​ $ 265.8 ​ Fixed maturities, trading ​ ​ 178.8 ​ ​ 268.2 ​ Other investments ​ ​ 63.7 ​ ​ 10.4 ​ Cash and cash equivalents ​ ​ 302.4 ​ ​ 394.9 ​ Income taxes receivable ​ ​ 7.4 ​ 11.1 ​ Deferred income taxes ​ ​ 371.2 ​ 344.4 ​ Amounts receivable from subsidiaries ​ ​ 4.7 ​ 3.8 ​ Other assets ​ ​ 27.1 ​ 25.5 ​ Investment in unconsolidated entities ​ ​ 19,714.3 ​ 17,539.6 ​ Total assets ​ $ 21,482.8 ​ $ 18,863.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ Long-term debt ​ $ 4,223.3 ​ $ 3,625.5 ​ Accrued investment payable ​ ​ 25.3 ​ 25.4 ​ Pension liability ​ ​ 668.9 ​ ​ 590.6 ​ Other liabilities ​ ​ 6.4 ​ ​ 4.2 ​ Total liabilities ​ ​ 4,923.9 ​ 4,245.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ Stockholders' equity ​ ​ ​ ​ ​ ​ ​ Common stock, par value $.01 per share; 2,500 million shares authorized; 481.9 million and 479.3 million shares issued as of 2020 and 2019; 273.3 million and 276.6 million shares outstanding as of 2020 and 2019 ​ ​ 4.8 ​ 4.8 ​ Additional paid-in capital ​ ​ 10,321.6 ​ 10,182.6 ​ Retained earnings ​ ​ 11,838.0 ​ 11,074.3 ​ Accumulated other comprehensive income ​ ​ 2,383.1 ​ 1,037.9 ​ Treasury stock, at cost (208.6 million and 202.7 million shares as of 2020 and 2019) ​ ​ (7,988.6) ​ (7,681.6) ​ Total stockholders' equity attributable to Principal Financial Group, Inc. ​ ​ 16,558.9 ​ 14,618.0 ​ Total liabilities and stockholders' equity ​ $ 21,482.8 ​ $ 18,863.7 ​ ​ See accompanying notes. ​ Statements of Operations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net investment income ​ $ 13.3 ​ $ 19.4 ​ $ 25.8 ​ Net realized capital gains (losses) ​ ​ 7.0 ​ ​ 12.3 ​ ​ (8.2) ​ Total revenues ​ ​ 20.3 ​ ​ 31.7 ​ ​ 17.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other operating costs and expenses ​ ​ 200.0 ​ ​ 210.9 ​ ​ 191.9 ​ Total expenses ​ ​ 200.0 ​ ​ 210.9 ​ ​ 191.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss before income taxes ​ ​ (179.7) ​ ​ (179.2) ​ ​ (174.3) ​ Income tax benefits ​ ​ (46.1) ​ ​ (44.2) ​ ​ (62.5) ​ Equity in the net income of subsidiaries ​ ​ 1,529.4 ​ ​ 1,529.2 ​ ​ 1,658.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to Principal Financial Group, Inc. ​ $ 1,395.8 ​ $ 1,394.2 ​ $ 1,546.5 ​ ​ See accompanying notes. ​ Statements of Cash Flows ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,395.8 ​ $ 1,394.2 ​ $ 1,546.5 ​ Adjustments to reconcile net income to net cash provided by (used in) operating activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net realized capital (gains) losses ​ ​ (7.0) ​ ​ (12.3) ​ ​ 8.2 ​ Stock-based compensation ​ ​ 1.4 ​ ​ 1.3 ​ ​ 2.9 ​ Equity in the net income of subsidiaries ​ ​ (1,529.4) ​ ​ (1,529.2) ​ ​ (1,658.3) ​ Changes in: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash flows for trading securities and equity securities with operating intent ​ ​ 88.4 ​ ​ 48.7 ​ ​ 32.4 ​ Current and deferred income taxes (benefits) ​ ​ (13.5) ​ ​ (31.0) ​ ​ 15.7 ​ Other ​ ​ 49.1 ​ ​ 135.4 ​ ​ (79.8) ​ Net cash provided by (used in) operating activities ​ ​ (15.2) ​ ​ 7.1 ​ ​ (132.4) ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ ​ (736.5) ​ ​ (251.5) ​ ​ (210.9) ​ Maturities ​ ​ 193.7 ​ ​ 200.0 ​ ​ 2.3 ​ Net purchases of property and equipment ​ ​ (0.1) ​ ​ (0.1) ​ ​ (0.1) ​ Net change in other investments ​ ​ (50.0) ​ ​ (34.0) ​ ​ (2.2) ​ Dividends and returns of capital received from unconsolidated entities ​ ​ 799.1 ​ ​ 494.2 ​ ​ 1,041.6 ​ Net cash provided by investing activities ​ ​ 206.2 ​ ​ 408.6 ​ ​ 830.7 ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ ​ 42.8 ​ ​ 37.7 ​ ​ 64.0 ​ Acquisition of treasury stock ​ ​ (307.0) ​ ​ (281.0) ​ ​ (671.6) ​ Dividends to common stockholders ​ ​ (614.5) ​ ​ (606.0) ​ ​ (598.6) ​ Issuance of long-term debt ​ ​ 595.2 ​ ​ 493.6 ​ ​ — ​ Net cash used in financing activities ​ ​ (283.5) ​ ​ (355.7) ​ ​ (1,206.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase (decrease) in cash and cash equivalents ​ ​ (92.5) ​ ​ 60.0 ​ ​ (507.9) ​ Cash and cash equivalents at beginning of year ​ ​ 394.9 ​ ​ 334.9 ​ ​ 842.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents at end of year ​ $ 302.4 ​ $ 394.9 ​ $ 334.9 ​ ​ See accompanying notes. ​ (1) Basis of Presentation The accompanying condensed financial information should be read in conjunction with the consolidated financial statements and notes thereto of Principal Financial Group, Inc. In the parent company only financial statements, our investment in unconsolidated entities is stated at cost plus equity in undistributed earnings of subsidiaries. Principal Financial Group, Inc. sponsors nonqualified benefit plans for select employees and agents and is responsible for the obligations of these plans. Nonqualified plan assets are held in Rabbi trusts for the benefit of all nonqualified plan participants. The invested assets and benefit plan liabilities reported in the statements of financial position exclude amounts held in these trusts. The Rabbi trusts had $801.7 million and $731.9 million of plan assets and $653.3 million and $593.7 million of benefit plan liabilities as of December 31, 2020 and 2019, respectively. (2) Dividends and Returns of Capital Received from Unconsolidated Entities The parent company received cash dividends and returns of capital totaling $799.1 million, $494.2 million and $1,041.6 million from subsidiaries in 2020, 2019 and 2018, respectively.

Schedule III - Supplementary In

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2020
Schedule III - Supplementary Insurance Information
Schedule III - Supplementary Insurance Information	Schedule III - Supplementary Insurance Information As of December 31, 2020 and 2019 and for each of the years ended December 31, 2020, 2019 and 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractholder ​ ​ Deferred ​ Future policy ​ and other ​ ​ acquisition ​ benefits and ​ policyholder Segment costs claims funds ​ ​ (in millions) 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 730.4 ​ $ 28,134.1 ​ $ 35,576.0 ​ Principal Global Investors ​ ​ — ​ ​ — ​ ​ — ​ Principal International ​ ​ 11.2 ​ ​ 5,109.5 ​ ​ 1,167.3 ​ U.S. Insurance Solutions ​ ​ 2,668.1 ​ ​ 11,800.3 ​ ​ 7,909.5 ​ Corporate ​ ​ — ​ ​ 163.3 ​ ​ (355.7) ​ Total ​ $ 3,409.7 ​ $ 45,207.2 ​ $ 44,297.1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 833.9 ​ $ 25,305.1 ​ $ 33,814.4 ​ Principal Global Investors ​ ​ — ​ ​ — ​ ​ — ​ Principal International ​ ​ 11.3 ​ ​ 4,537.1 ​ ​ 1,145.0 ​ U.S. Insurance Solutions ​ ​ 2,676.1 ​ ​ 10,823.5 ​ ​ 7,720.0 ​ Corporate ​ ​ — ​ ​ 172.5 ​ ​ (352.5) ​ Total ​ $ 3,521.3 ​ $ 40,838.2 ​ $ 42,326.9 ​ ​ Schedule III - Supplementary Insurance Information - (continued) As of December 31, 2020 and 2019 and for each of the years ended December 31, 2020, 2019 and 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of ​ ​ ​ ​ ​ Premiums and ​ Net ​ Benefits, claims ​ deferred ​ Other ​ ​ other ​ investment ​ and settlement ​ acquisition ​ operating Segment considerations income (1) expenses costs expenses (1) ​ ​ (in millions) 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 3,221.0 ​ $ 2,457.9 ​ $ 4,899.4 ​ $ 82.2 ​ $ 1,578.2 ​ Principal Global Investors ​ ​ — ​ ​ 5.6 ​ ​ — ​ ​ — ​ ​ 1,029.6 ​ Principal International ​ ​ 156.6 ​ ​ 446.8 ​ ​ 440.7 ​ ​ 1.2 ​ ​ 416.8 ​ U.S. Insurance Solutions ​ ​ 2,659.8 ​ ​ 850.6 ​ ​ 2,937.2 ​ ​ 304.7 ​ ​ 936.9 ​ Corporate ​ ​ — ​ ​ 129.7 ​ ​ 4.2 ​ ​ — ​ ​ 296.9 ​ Total ​ $ 6,037.4 ​ $ 3,890.6 ​ $ 8,281.5 ​ $ 388.1 ​ $ 4,258.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 4,862.7 ​ $ 2,420.4 ​ $ 6,527.8 ​ $ 87.8 ​ $ 1,403.5 ​ Principal Global Investors ​ ​ — ​ ​ 10.1 ​ ​ — ​ ​ — ​ ​ 1,028.5 ​ Principal International ​ ​ 393.3 ​ ​ 575.9 ​ ​ 728.3 ​ ​ 1.3 ​ ​ 436.0 ​ U.S. Insurance Solutions ​ ​ 2,610.6 ​ ​ 854.5 ​ ​ 2,639.2 ​ ​ 257.9 ​ ​ 946.5 ​ Corporate ​ ​ — ​ ​ 137.5 ​ ​ 10.5 ​ ​ — ​ ​ 342.4 ​ Total ​ $ 7,866.6 ​ $ 3,998.4 ​ $ 9,905.8 ​ $ 347.0 ​ $ 4,156.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 3,635.9 ​ $ 2,195.2 ​ $ 5,099.0 ​ $ 124.5 ​ $ 1,140.7 ​ Principal Global Investors ​ — ​ ​ 4.2 ​ ​ — ​ ​ — ​ ​ 1,168.0 ​ Principal International ​ 317.2 ​ ​ 494.9 ​ ​ 646.6 ​ ​ 1.3 ​ ​ 451.0 ​ U.S. Insurance Solutions ​ 2,456.5 ​ ​ 815.1 ​ ​ 2,444.6 ​ ​ 127.7 ​ ​ 925.4 ​ Corporate ​ — ​ ​ 119.8 ​ ​ 2.3 ​ ​ — ​ ​ 198.1 ​ Total ​ $ 6,409.6 ​ $ 3,629.2 ​ $ 8,192.5 ​ $ 253.5 ​ $ 3,883.2 ​ (1) Allocations of net investment income and certain operating expenses are based on a number of assumptions and estimates. Reported operating results would change by segment if different methods were applied.

Schedule IV - Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2020
Schedule IV - Reinsurance
Schedule IV - Reinsurance	Schedule IV - Reinsurance As of December 31, 2020, 2019 and 2018 and for each of the years then ended ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Percentage ​ ​ ​ ​ ​ Ceded to ​ Assumed ​ ​ ​ ​ of amount ​ ​ Gross ​ other ​ from other ​ ​ ​ ​ assumed ​ amount companies companies Net amount to net ​ ​ ($ in millions) 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Life insurance in force ​ $ 626,155.6 ​ $ 377,308.2 ​ $ 904.1 ​ $ 249,751.5 ​ 0.4 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Life insurance and annuities ​ $ 4,608.7 ​ $ 453.1 ​ $ 1.7 ​ $ 4,157.3 ​ — % Accident and health insurance ​ ​ 2,036.7 ​ ​ 156.6 ​ ​ — ​ ​ 1,880.1 ​ — % Total ​ $ 6,645.4 ​ $ 609.7 ​ $ 1.7 ​ $ 6,037.4 ​ — % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Life insurance in force ​ $ 577,735.3 ​ $ 368,583.0 ​ $ 999.5 ​ $ 210,151.8 ​ 0.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Life insurance and annuities ​ $ 6,424.8 ​ $ 407.5 ​ $ 1.6 ​ $ 6,018.9 ​ — % Accident and health insurance ​ ​ 2,003.3 ​ ​ 155.6 ​ ​ — ​ ​ 1,847.7 ​ — % Total ​ $ 8,428.1 ​ $ 563.1 ​ $ 1.6 ​ $ 7,866.6 ​ — % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Life insurance in force ​ $ 530,828.6 ​ $ 324,691.3 ​ $ 1,028.6 ​ $ 207,165.9 ​ 0.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Life insurance and annuities ​ $ 5,055.8 ​ $ 359.9 ​ $ 1.7 ​ $ 4,697.6 ​ — % Accident and health insurance ​ 1,872.5 ​ ​ 160.5 ​ ​ — ​ ​ 1,712.0 ​ — % Total ​ $ 6,928.3 ​ $ 520.4 ​ $ 1.7 ​ $ 6,409.6 ​ — % ​

Nature of Operations and Sign_2

Nature of Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Nature of Operations and Significant Accounting Policies
Basis of Presentation - Policy	Basis of Presentation The accompanying consolidated financial statements include the accounts of PFG and all other entities in which we directly or indirectly have a controlling financial interest as well as those variable interest entities (“VIEs”) in which we are the primary beneficiary. The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). All significant intercompany accounts and transactions have been eliminated. Uncertainties, including those associated with the novel coronavirus ("COVID-19"), may impact our business, results of operations, financial condition and liquidity. Our use of estimates and assumptions affect amounts reported and disclosed and includes, but is not limited to, the fair value of investments in the absence of quoted market values, investment impairments and valuation allowances, the fair value of derivatives, deferred acquisition costs ("DAC") and other actuarial balances, measurement of goodwill and intangible assets, the liability for future policy benefits and claims, the value of pension and other postretirement benefits and accounting for income taxes and the valuation of deferred tax assets. Our estimates and assumptions could change in the future as more information becomes known about the impact of COVID-19. Our results of operations and financial condition may also be impacted by other uncertainties including evolving regulatory, legislative and standard-setter accounting interpretations and guidance.
Consolidation - Policy	Consolidation We have relationships with various special purpose entities and other legal entities that must be evaluated to determine if the entities meet the criteria of a VIE or a voting interest entity (“VOE”). This assessment is performed by reviewing contractual, ownership and other rights, including involvement of related parties, and requires use of judgment. First, we determine if we hold a variable interest in an entity by assessing if we have the right to receive expected losses and expected residual returns of the entity. If we hold a variable interest, then the entity is assessed to determine if it is a VIE. An entity is a VIE if the equity at risk is not sufficient to support its activities, if the equity holders lack a controlling financial interest or if the entity is structured with non-substantive voting rights. In addition to the previous criteria, if the entity is a limited partnership or similar entity, it is a VIE if the limited partners do not have the power to direct the entity’s most significant activities through substantive kick-out rights or participating rights. A VIE is evaluated to determine the primary beneficiary. The primary beneficiary of a VIE is the enterprise with (1) the power to direct the activities of a VIE that most significantly impact the entity's economic performance and (2) the obligation to absorb losses of the entity or the right to receive benefits from the entity that could potentially be significant to the VIE. When we are the primary beneficiary, we are required to consolidate the entity in our financial statements. We reassess our involvement with VIEs on a quarterly basis. For further information about VIEs, refer to Note 3, Variable Interest Entities. If an entity is not a VIE, it is considered a VOE. VOEs are generally consolidated if we own a greater than 50% voting interest. If we determine our involvement in an entity no longer meets the requirements for consolidation under either the VIE or VOE models, the entity is deconsolidated. Entities in which we have management influence over the operating and financing decisions but are not required to consolidate, other than investments accounted for at fair value under the fair value option, are reported using the equity method.
Recent Accounting Pronouncements - Policy	Recent Accounting Pronouncements ​ ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Standards not yet adopted: ​ ​ Targeted improvements to the accounting for long-duration insurance contracts This authoritative guidance updates certain requirements in the accounting for long-duration insurance and annuity contracts. 1. The assumptions used to calculate the liability for future policy benefits on traditional and limited-payment contracts will be reviewed and updated periodically. Cash flow assumptions will be reviewed at least annually and updated when necessary with the impact recognized in net income. Discount rate assumptions are prescribed as the current upper-medium grade (low credit risk) fixed income instrument yield and will be updated quarterly with the impact recognized in other comprehensive income (“OCI”). 2. Market risk benefits, which are contracts or contract features that provide protection to the policyholder from capital market risk and expose us to other-than-nominal capital market risk, are measured at fair value. The periodic change in fair value is recognized in net income with the exception of the periodic change in fair value related to our own nonperformance risk, which is recognized in OCI. 3. DAC and other actuarial balances for all insurance and annuity contracts will be amortized on a constant basis over the expected term of the related contracts. 4. Additional disclosures are required, including disaggregated rollforwards of significant insurance liabilities and other account balances as well as disclosures about significant inputs, judgments, assumptions and methods used in measurement. The guidance for the liability for future policy benefits for traditional and limited-payment contracts and DAC will be applied on a modified retrospective basis; that is, to contracts in force as of the beginning of the earliest period presented based on their existing carrying amounts. An entity may elect to apply the changes retrospectively. The guidance for market risk benefits will be applied retrospectively. Early adoption is permitted. January 1, 2023 Our implementation and evaluation process to date includes, but is not limited to the following: ● ● ● ● ● ● ● ● ● ● As we progress through our implementation, we will be able to better assess the impact to our consolidated financial statements; however, we expect this guidance to significantly change how we account for many of our insurance and annuity products. ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Simplifying the accounting for income taxes This authoritative guidance simplifies the accounting for income taxes by removing certain exceptions, including exceptions related to the incremental approach for intraperiod tax allocation, calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. Also, the guidance clarifies the accounting for franchise taxes, transactions that result in a step-up in the tax basis of goodwill and enacted changes in tax laws or rates. It specifies that an entity is not required to allocate the consolidated amount of current and deferred tax expense to a legal entity that is not subject to tax in its separate financial statements, although an entity may elect to do so. The guidance will be applied based on varying transition methods defined by amendment. Early adoption is permitted. January 1, 2021 This guidance is not expected to have a material impact on our consolidated financial statements. Standards adopted: ​ ​ Facilitation of the effects of reference rate reform on financial reporting This authoritative guidance provides optional expedients and exceptions for contracts and hedging relationships affected by reference rate reform. An entity may elect not to apply certain modification accounting requirements to contracts affected by reference rate reform and instead account for the modified contract as a continuation of the existing contract. Also, an entity may apply optional expedients to continue hedge accounting for hedging relationships in which the critical terms change due to reference rate reform. This guidance eases the financial reporting impacts of reference rate reform on contracts and hedging relationships and is effective until December 31, 2022. March 12, 2020 We adopted the guidance upon issuance prospectively and elected the applicable optional expedients and exceptions for contracts and hedging relationships impacted by reference rate reform through December 31, 2022. The guidance did not have an impact on our consolidated financial statements upon adoption. Goodwill impairment testing This authoritative guidance simplifies how an entity is required to test goodwill for impairment by eliminating Step 2 (which measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill to the carrying amount of that goodwill) from the goodwill impairment test. A goodwill impairment loss will be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Entities will continue to have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. January 1, 2020 This guidance reduces complexity and costs associated with performing a Step 2 test, should one be needed in the future. This guidance did not have a material impact on our consolidated financial statements at adoption. Credit losses This authoritative guidance requires entities to use a current expected credit loss (“CECL”) model to measure impairment for most financial assets that are not recorded at fair value through net income. Under the CECL model, an entity will estimate lifetime expected credit losses considering available relevant information about historical events, current conditions and reasonable and supportable forecasts. The CECL model does not apply to available-for-sale debt securities; however, the credit loss calculation and subsequent recoveries for available-for-sale securities are required to be recorded through an allowance. This guidance also expands the required credit loss disclosures. January 1, 2020 We adopted the guidance using the modified retrospective approach. A cumulative effect adjustment of $8.4 million was recorded as a decrease to retained earnings. We recorded an offsetting increase in the allowance for credit loss for mortgage loans, reinsurance recoverables and commitments and a decrease for deferred tax impacts. See Note 4, Investments, for further details. ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Implementation costs in a cloud computing arrangement that is a service contract This authoritative guidance aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This guidance can be applied either retrospectively or prospectively. January 1, 2019 The effective date of the guidance was January 1, 2020; however, we elected to early-adopt this guidance on a prospective basis, effective January 1, 2019. This guidance did not have a material impact on our consolidated financial statements. Nonemployee share-based payment accounting This authoritative guidance simplifies the accounting for share-based payments to nonemployees by generally aligning it with the accounting for share-based payments to employees. Under the guidance, the measurement of equity-classified nonemployee awards will be fixed at the grant date, where previously the measurement was fixed at performance completion date. The guidance will be applied to equity-classified nonemployee awards for which a measurement date has not been established as of the date of adoption. January 1, 2019 This guidance did not have a material impact on our consolidated financial statements. ​ Leases This authoritative guidance requires lessee recognition of lease assets and lease liabilities on the consolidated statements of financial position. The concept of an operating lease, where the lease assets and liabilities are not reported on the consolidated statements of financial position, is eliminated under the new guidance. For lessors, the guidance modifies lease classification criteria and accounting for certain types of leases. Other key aspects of the guidance relate to the removal of the current real estate-specific guidance and new presentation and disclosure requirements. Lessees and lessors are required to recognize and measure leases using a modified retrospective approach, which includes certain optional practical expedients that may be elected. We elected the alternative transition method, which allows entities to initially apply the new standard at the adoption date and recognize a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption. January 1, 2019 We adopted the guidance using the modified retrospective approach. A cumulative effect adjustment of $4.0 million was recorded as an increase to retained earnings. See Note 12, Contingencies, Guarantees, Indemnifications and Leases, for further details. Targeted improvements to accounting for hedging activities This authoritative guidance updated certain recognition and measurement requirements for hedge accounting. The objective of the guidance is to more closely align the economics of a company’s risk management activities in its financial results and reduce the complexity of applying hedge accounting. The updates included the expansion of hedging strategies that are eligible for hedge accounting, elimination of the separate measurement and reporting of hedge ineffectiveness, presentation of the changes in the fair value of the hedging instrument in the same consolidated statement of operations line as the earnings effect of the hedged item and simplification of hedge effectiveness assessments. This guidance also included new disclosures. January 1, 2019 This guidance did not have a material impact on our consolidated financial statements. See Note 5, Derivative Financial Instruments, for further details. ​ ​ ​ ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Premium amortization on purchased callable debt securities This authoritative guidance applies to entities that hold certain non-contingently callable debt securities, where the amortized cost basis is at a premium to the price repayable by the issuer at the earliest call date. Under the guidance the premium will be amortized to the first call date. January 1, 2019 This guidance did not have a material impact on our consolidated financial statements. Reclassification of certain tax effects from accumulated other comprehensive income This authoritative guidance permits a reclassification from accumulated other comprehensive income (“AOCI”) to retained earnings for the stranded tax effects resulting from U.S. tax legislation enacted on December 22, 2017, which is referred to as the ‘‘Tax Cuts and Jobs Act’’ (‘‘U.S. tax reform’’). The amount of that reclassification includes the change in corporate income tax rate, as well as an election to include other income tax effects related to the application of U.S. tax reform. The guidance also requires disclosures about stranded tax effects. January 1, 2018 The effective date of the guidance was January 1, 2019; however, we elected to early adopt the guidance. The guidance was applied at the beginning of the period of adoption and comparative periods were not restated. We reclassified the stranded tax effects in AOCI resulting from U.S. tax reform, which includes the change in corporate income tax rate and an election to reclassify the tax effects of the one-time deemed repatriation tax. A reclassification of $77.6 million was recorded as an increase to AOCI and a decrease to retained earnings. Revenue recognition This authoritative guidance replaces all general and most industry specific revenue recognition guidance currently prescribed by U.S. GAAP. The core principle is that an entity recognizes revenue to reflect the transfer of a promised good or service to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for that good or service. This guidance also provides clarification on when an entity is a principal or an agent in a transaction. In addition, the guidance updates the accounting for certain costs associated with obtaining and fulfilling a customer contract. The guidance may be applied using one of the following two methods: (1) retrospectively to each prior reporting period presented, or (2) retrospectively with the cumulative effect of initially applying the standard recognized at the date of initial application. January 1, 2018 We adopted the guidance using the modified retrospective approach. The guidance did not have a material impact on our consolidated financial statements. A cumulative effect adjustment of $39.7 million was recorded as a decrease to total stockholders' equity. See Note 17, Revenues from Contracts with Customers, for further details. Income tax - intra-entity transfers of assets This authoritative guidance requires entities to recognize current and deferred income tax resulting from an intra-entity asset transfer when the transfer occurs. Prior to issuance of this guidance, U.S. GAAP did not allow recognition of income tax consequences until the asset had been sold to a third party. This guidance requires adoption through a cumulative effect adjustment to the consolidated statements of financial position as of the beginning of the fiscal year of adoption. January 1, 2018 ​ We adopted the guidance using the modified retrospective approach. A cumulative effect adjustment of $8.7 million was recorded as an increase to retained earnings. In addition, other assets and deferred income taxes decreased $21.1 million and $29.8 million, respectively, due to the adoption of this guidance. ​ ​ ​ ​ ​ ​ Description Date of Effect on our consolidated Financial instruments - recognition and measurement January 1, 2018 We adopted this guidance using the modified retrospective approach. A cumulative effect adjustment of $1.0 million was recorded as a decrease to AOCI and a corresponding increase to retained earnings. The guidance did not have a material impact on our consolidated financial statements. See Note 4, Investments, for further details. Nonfinancial asset derecognition and partial sales of nonfinancial assets This authoritative guidance clarifies the scope of the recently established guidance on nonfinancial asset derecognition and the accounting for partial sales of nonfinancial assets. The guidance conforms the derecognition guidance on nonfinancial assets with the model for transactions in the new revenue recognition standard. January 1, 2018 The guidance did not have a material impact on our consolidated financial statements. Presentation of net periodic pension cost and net periodic postretirement benefit cost This authoritative guidance requires that an employer disaggregate the service cost component from the other components of net benefit cost. The guidance also provides explicit guidance on the presentation of the service cost component and the other components of net benefit cost in the consolidated statements of operations and allows only the service cost component of net benefit cost to be eligible for capitalization. January 1, 2018 The guidance did not have a material impact on our consolidated financial statements. Definition of a business This authoritative guidance clarifies the definition of a business to assist with evaluating when transactions involving an integrated set of assets and activities (a “set”) should be accounted for as acquisitions or disposals of assets or businesses. The guidance requires that when substantially all of the fair value of the gross assets acquired or disposed of is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. The guidance also requires a set to include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output to be considered a business. Lastly, the guidance removes the evaluation of whether a market participant could replace missing elements and narrows the definition of outputs by more closely aligning it with how outputs are described in the revenue recognition guidance. The guidance will be applied prospectively. January 1, 2018 The guidance did not have a material impact on our consolidated financial statements. ​ When we adopt new accounting standards, we have a process in place to perform a thorough review of the pronouncement, identify the financial statement and system impacts and create an implementation plan among our impacted business units to ensure we are compliant with the pronouncement on the date of adoption. This includes having effective processes and controls in place to support the reported amounts. Each of the standards listed above is in varying stages in our implementation process based on its issuance and adoption dates. We are on track to implement guidance by the respective effective dates.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of our consolidated financial statements and accompanying notes requires management to make estimates and assumptions that affect the amounts reported and disclosed. These estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed in the consolidated financial statements and accompanying notes. The most critical estimates include those used in determining: ● the fair value of investments in the absence of quoted market values; ● investment impairments and valuation allowances; ● the fair value of and accounting for derivatives; ● the DAC and other actuarial balances where the amortization is based on estimated gross profits (“EGPs”); ● the measurement of goodwill, indefinite lived intangible assets, finite lived intangible assets and related impairments or amortization, if any; ● the liability for future policy benefits and claims; ● the value of our pension and other postretirement benefit obligations and ● accounting for income taxes and the valuation of deferred tax assets. A description of such critical estimates is incorporated within the discussion of the related accounting policies that follow. In applying these policies, management makes subjective and complex judgments that frequently require estimates about matters that are inherently uncertain. Actual results could differ from these estimates.
Closed Block	Closed Block Principal Life Insurance Company (“Principal Life”) operates a closed block (“Closed Block”) for the benefit of individual participating dividend-paying policies in force at the time of the 1998 mutual insurance holding company (“MIHC”) formation. See Note 6, Closed Block, for further details.
Cash and Cash Equivalents - Policy	Cash and Cash Equivalents Cash and cash equivalents include cash on hand, money market instruments and other debt issues with a maturity date of three months or less when purchased.
Investments - Policy	Investments Fixed maturities include bonds, asset-backed securities (“ABS”), redeemable preferred stock and certain non-redeemable preferred securities. Equity securities include mutual funds, common stock, non-redeemable preferred stock and required regulatory investments. We classify fixed maturities as either available-for-sale or trading at the time of the purchase and, accordingly, carry them at fair value. Equity securities are also carried at fair value. See Note 14, Fair Value Measurements, for methodologies related to the determination of fair value. Unrealized gains and losses related to fixed maturities, available-for-sale, excluding those in fair value hedging relationships, are reflected in stockholders' equity, net of adjustments associated with DAC and related actuarial balances, derivatives in cash flow hedge relationships and applicable income taxes. Mark-to-market adjustments on equity securities, unrealized gains and losses related to hedged portions of fixed maturities, available-for-sale in fair value hedging relationships prior to 2019 and mark-to-market adjustments on certain fixed maturities, trading are reflected in net realized capital gains (losses). Beginning in 2019, unrealized gains and losses related to hedged portions of fixed maturities, available-for-sale in fair value hedging relationships are reflected in net investment income. Mark-to-market adjustments related to certain securities carried at fair value with an investment objective to realize economic value through mark-to-market changes are reflected in net investment income. The amortized cost of fixed maturities includes cost adjusted for amortization of premiums and discounts, computed using the interest method. The amortized cost of fixed maturities, available-for-sale is adjusted for changes in fair value of the hedged portions of securities in fair value hedging relationships and excludes accrued interest receivable. Accrued interest receivable is reported in accrued investment income on the consolidated statements of financial position. Beginning in 2020, fixed maturities, available-for-sale are subject to an allowance for credit loss and changes in the allowance are reported in net income as a component of net realized capital gains (losses). Prior to 2020, the amortized cost of fixed maturities classified as available-for-sale was adjusted for declines in value that were other than temporary. Prior to 2020, impairments in value deemed to be other than temporary were primarily reported in net income as a component of net realized capital gains (losses), with noncredit impairment losses for certain fixed maturities, available-for-sale reported in OCI. Interest income, as well as prepayment fees and the amortization of the related premium or discount, is reported in net investment income. For loan-backed and structured securities, we recognize income using a constant effective yield based on currently anticipated cash flows. Commercial and residential mortgage loans are generally reported at cost adjusted for amortization of premiums and accrual of discounts, computed using the interest method and net of valuation allowances. Amortized cost excludes accrued interest receivable. Interest income is accrued on the principal amount of the loan based on the loan’s contractual interest rate. Interest income, as well as prepayment of fees and the amortization of the related premium or discount, is reported in net investment income on the consolidated statements of operations. Accrued interest receivable is reported in accrued investment income on the consolidated statements of financial position. Any changes in the loan valuation allowances are reported in net realized capital gains (losses) on the consolidated statements of operations. See Note 4, Investments, for further details of our valuation allowance. Our commercial and residential mortgage loan portfolios can include loans that have been modified. We assess loan modifications on a case-by-case basis to evaluate whether a troubled debt restructuring (“TDR”) has occurred. In response to COVID-19, the Coronavirus Aid, Relief and Economic Security Act, which was subsequently amended by the Consolidated Appropriations Act, 2021, (collectively the “CARES Act”) provides a temporary suspension of TDR accounting for certain COVID-19 related loan modifications where the loan was not more than 30 days past due as of December 31, 2019. We elected the TDR relief in the CARES Act beginning in the second quarter of 2020. The CARES Act TDR relief does not apply to modifications completed subsequent to the earlier of 60 days after the national emergency related to COVID-19 ends, or January 1, 2022. In addition, the Interagency Statement on Loan Modifications and Reporting for Financial Institutions Working with Customers Affected by the Coronavirus (As Revised on April 7, 2020) (“Interagency Statement”) provides additional guidance to determine if a short-term COVID-19 related loan modification is a TDR. We consider the CARES Act and the Interagency Statement when assessing loan modifications to determine whether a TDR has occurred. See Note 4, Investments, under the caption “Mortgage Loan Modifications” for further details. Real estate investments are reported at cost less accumulated depreciation. The initial cost bases of properties acquired through loan foreclosures are the lower of the fair market values of the properties at the time of foreclosure or the outstanding loan balance. Buildings and land improvements are generally depreciated on the straight-line method over the estimated useful life of improvements and tenant improvement costs are depreciated on the straight-line method over the term of the related lease. We recognize impairment losses for properties when indicators of impairment are present and a property's expected undiscounted cash flows are not sufficient to recover the property's carrying value. In such cases, the cost basis of the property is reduced to fair value. Real estate expected to be disposed is carried at the lower of cost or fair value, less cost to sell, with valuation allowances established accordingly and depreciation no longer recognized. The carrying amount of real estate held for sale was $2.0 million and $169.8 million as of December 31, 2020 and 2019, respectively. Any impairment losses and any changes in valuation allowances are reported in net income. Net realized capital gains and losses on sales of investments are determined on the basis of specific identification. In general, in addition to realized capital gains and losses on investment sales and periodic settlements on derivatives not designated as hedges, we report gains and losses related to the following in net realized capital gains (losses) on the consolidated statements of operations: mark-to-market adjustments on equity securities, mark-to-market adjustments on certain fixed maturities, trading, mark-to-market adjustments on sponsored investment funds, mark-to-market adjustments on derivatives not designated as hedges, cash flow hedge gains (losses) when the hedged item impacts realized capital gains (losses), changes in the valuation allowance for fixed maturities, available-for-sale and certain financing receivables, impairments of real estate held for investment, impairments of equity method investments and, prior to 2020, other-than-temporary impairments of securities and subsequent realized recoveries. Investment gains and losses on sales of certain real estate held for sale due to investment strategy and mark-to-market adjustments on certain securities carried at fair value with an investment objective to realize economic value through mark-to-market changes are reported as net investment income and are excluded from net realized capital gains (losses). Policy loans and certain other investments are reported at cost. Interests in unconsolidated entities, joint ventures and partnerships are generally accounted for using the equity method. We have other investments reported at fair value or for which the fair value option has been elected in prior periods. See Note 14, Fair Value Measurements, for detail on these investments.
Derivatives - Policy	Derivatives Overview Derivatives are financial instruments whose values are derived from interest rates, foreign exchange rates, financial indices or the values of securities. Derivatives generally used by us include swaps, options, futures and forwards. Derivative positions are either assets or liabilities in the consolidated statements of financial position and are measured at fair value, generally by obtaining quoted market prices or through the use of pricing models. See Note 14, Fair Value Measurements, for policies related to the determination of fair value. Fair values can be affected by changes in interest rates, foreign exchange rates, financial indices, values of securities, credit spreads, and market volatility and liquidity. Accounting and Financial Statement Presentation We designate derivatives as either: (a) a hedge of the exposure to changes in the fair value of a recognized asset or liability or an unrecognized firm commitment, including those denominated in a foreign currency (“fair value hedge”); (b) a hedge of a forecasted transaction or the exposure to variability of cash flows to be received or paid related to a recognized asset or liability, including those denominated in a foreign currency (“cash flow hedge”); (c) a hedge of a net investment in a foreign operation or (d) a derivative not designated as a hedging instrument. Our accounting for the ongoing changes in fair value of a derivative depends on the intended use of the derivative and the designation, as described above, and is determined when the derivative contract is entered into or at the time of redesignation. Hedge accounting is used for derivatives that are specifically designated in advance as hedges and that reduce our exposure to an indicated risk by having a high correlation between changes in the value of the derivatives and the items being hedged at both the inception of the hedge and throughout the hedge period. Cash flows associated with derivatives are included within operating and financing activities in the consolidated statements of cash flows. ​ Fair Value Hedges. Cash Flow Hedges. Net Investment in a Foreign Operation Hedge. Non-Hedge Derivatives. Hedge Documentation and Effectiveness Testing. We use qualitative and quantitative methods to assess hedge effectiveness. Qualitative methods may include monitoring changes to terms and conditions and counterparty credit ratings. Quantitative methods may include statistical tests including regression analysis and minimum variance and dollar offset techniques. Termination of Hedge Accounting. If it is determined that a derivative no longer qualifies as an effective hedge, the derivative will continue to be carried on the consolidated statements of financial position at its fair value, with changes in fair value recognized prospectively in net realized capital gains (losses). The asset or liability under a fair value hedge will no longer be adjusted for changes in fair value pursuant to hedging rules and the existing basis adjustment is amortized to the consolidated statements of operations line associated with the asset or liability. The component of AOCI related to discontinued cash flow hedges that are no longer highly effective is amortized to the consolidated statements of operations consistent with the net income impacts of the original hedged cash flows. If a cash flow hedge is discontinued because it is probable the hedged forecasted transaction will not occur, the deferred gain or loss is immediately reclassified from AOCI into net income. Embedded Derivatives.
Contractholder and Policyholder Liabilities - Policy	Contractholder and Policyholder Liabilities Contractholder and policyholder liabilities (contractholder funds, future policy benefits and claims and other policyholder funds) include reserves for investment contracts, individual and group annuities that provide periodic income payments, universal life insurance, variable universal life insurance, indexed universal life insurance, term life insurance, participating traditional individual life insurance, group dental and vision insurance, group critical illness, group accident, group short-term and long-term disability insurance, group life insurance, individual disability insurance and long-term care insurance. It also includes a provision for dividends on participating policies. Investment contracts are contractholders' funds on deposit with us and generally include reserves for pension and annuity contracts. Reserves on investment contracts are equal to the cumulative deposits less any applicable charges and withdrawals plus credited interest. Reserves for universal life, variable universal life and indexed universal life insurance contracts are equal to cumulative deposits less charges plus credited interest, which represents the account balances that accrue to the benefit of the policyholders. We hold additional reserves on certain long-duration contracts where benefit features result in gains in early years followed by losses in later years; universal life, variable universal life and indexed universal life insurance contracts that contain no lapse guarantee features; and annuities with guaranteed minimum death benefits. Reserves for individual and group annuities that provide periodic income payments, nonparticipating term life insurance and disability income contracts are computed on a basis of assumed investment yield, mortality, morbidity and expenses, including a provision for adverse deviation, which generally varies by plan, year of issue and policy duration. Investment yield is based on our experience. Mortality, morbidity and withdrawal rate assumptions are based on our experience and are periodically reviewed against both industry standards and experience. For long-duration insurance contracts, significant changes in experience or assumptions may require us to provide for expected future losses on a product by establishing premium deficiency reserves. Premium deficiency reserves may also be established for short-duration contracts to provide for expected future losses. Reserves for participating life insurance contracts are based on the net level premium reserve for death and endowment policy benefits. This net level premium reserve is calculated based on dividend fund interest rates and mortality rates guaranteed in calculating the cash surrender values described in the contract. Participating business represented approximately 5%, 6% and 7% of our life insurance in force and 20%, 23% and 26% of the number of life insurance policies in force as of December 31, 2020, 2019 and 2018, respectively. Participating business represented approximately 24%, 21% and 24% of life insurance premiums for the years ended December 31, 2020, 2019 and 2018, respectively. The amount of dividends to policyholders is declared annually by Principal Life's Board of Directors. The amount of dividends to be paid to policyholders is determined after consideration of several factors including interest, mortality, morbidity and other expense experience for the year and judgment as to the appropriate level of statutory surplus to be retained by Principal Life. At the end of the reporting period, Principal Life establishes a dividend liability for the pro rata portion of the dividends expected to be paid on or before the next policy anniversary date. Some of our policies and contracts require payment of fees or other policyholder assessments in advance for services that will be rendered over the estimated lives of the policies and contracts. These payments are established as unearned revenue liabilities upon receipt and included in other policyholder funds in the consolidated statements of financial position. These unearned revenue reserves are amortized to net income over the estimated lives of these policies and contracts in relation to the emergence of EGPs. Short-Duration Contracts We include the following group products in our short-duration insurance contracts disclosures: long-term disability (“LTD”), group life waiver, dental, vision, short-term disability (“STD”), critical illness, accident and group life. Future policy benefits and claims include reserves for group life and disability insurance that provide periodic income payments. These reserves are computed using assumptions of mortality, morbidity and investment performance. These assumptions are based on our experience, industry results, emerging trends and future expectations. Future policy benefits and claims also include reserves for incurred but unreported group disability, dental, vision, critical illness, accident and life insurance claims. We recognize claims costs in the period the service was provided to our policyholders. However, claims costs incurred in a particular period are not known with certainty until after we receive, process and pay the claims. We determine the amount of this liability using actuarial methods based on historical claim payment patterns as well as emerging cost trends, where applicable, to determine our estimate of claim liabilities. We have defined claim frequency as follows for each short-duration product: ● LTD: Claim frequency is based on submitted reserve claim counts. ● Group Life Waiver: Claim frequency is based on submitted reserve claim counts, consistent with LTD. ● Dental and Vision: Claim frequency is based on the claim form, which may include one or more procedures. ● STD, Critical Illness and Accident: Claim frequency is based on submitted claims. ● Group Life: Claim frequency is based on submitted life claims (lives, not coverages). We did not make any significant changes to our methodologies or assumptions used to calculate the liability for unpaid claims for short-duration contracts during 2020. Liability for Unpaid Claims The liability for unpaid claims for both long-duration and short-duration contracts is an estimate of the ultimate net cost of reported and unreported losses not yet settled. This liability is estimated using actuarial analyses and case basis evaluations. Although considerable variability is inherent in such estimates, we believe the liability for unpaid claims is adequate. These estimates are continually reviewed and, as adjustments to this liability become necessary, such adjustments are reflected in net income. Our liability for unpaid claims does not include any allocated claim adjustment expenses. We incur claim adjustment expenses for both long-duration and short-duration contracts that cannot be allocated to a specific claim. Our claim adjustment expense liability is estimated using actuarial analyses based on historical trends of expenses and expected claim runout patterns. See Note 8, Insurance Liabilities, under the caption “Liability for Unpaid Claims” for further details.
Recognition of Premiums and Other Considerations, Fees and Other Revenues and Benefits - Policy	Recognition of Premiums and Other Considerations, Fees and Other Revenues and Benefits Products with fixed and guaranteed premiums and benefits consist principally of whole life and term life insurance policies and individual disability income. Premiums from these products are recognized as premium revenue when due. Related policy benefits and expenses for individual life products are associated with earned premiums and result in the recognition of profits over the expected term of the policies and contracts. Immediate annuities with life contingencies include products with fixed and guaranteed annuity considerations and benefits and consist principally of group and individual single premium annuities with life contingencies. Annuity considerations from these products are recognized as premium revenue. However, the collection of these annuity considerations does not represent the completion of the earnings process, as we establish annuity reserves using estimates for mortality and investment assumptions, which include provision for adverse deviation as required by U.S. GAAP. We anticipate profits to emerge over the life of the annuity products as we earn investment income, pay benefits and release reserves. Group life, dental, vision, critical illness, accident and disability premiums are generally recorded as premium revenue over the term of the coverage. Certain group contracts contain experience premium refund provisions based on a pre-defined formula that reflects their claim experience. Experience premium refunds reduce revenue over the term of the coverage and are adjusted to reflect current experience. Related policy benefits and expenses are associated with earned premiums and result in the recognition of profits over the term of the policies and contracts. Fees for contracts providing claim processing or other administrative services are recorded as revenue over the period the service is provided. Universal life-type policies are insurance contracts with terms that are not fixed. Amounts received as payments for such contracts are not reported as premium revenues. Revenues for universal life-type insurance contracts consist of policy charges for the cost of insurance, policy initiation and administration, surrender charges and other fees that have been assessed against policy account values and investment income. Policy benefits and claims that are charged to expense include interest credited to contracts and benefit claims incurred in the period in excess of related policy account balances. Investment contracts do not subject us to significant risks arising from policyholder mortality or morbidity and consist primarily of guaranteed investment contracts (“GICs”), funding agreements and certain deferred annuities. Amounts received as payments for investment contracts are established as investment contract liability balances and are not reported as premium revenues. Revenues for investment contracts consist of investment income and policy administration charges. Investment contract benefits that are charged to expense include benefit claims incurred in the period in excess of related investment contract liability balances and interest credited to investment contract liability balances. Fees and other revenues are earned for asset management, investment advisory and distribution services provided to retail and institutional clients based largely upon contractual rates applied to the specified amounts in the clients’ portfolios, which include various platforms such as mutual funds, collective investment trusts and business trusts. Additionally, fees and other revenues are earned for administrative services performed including recordkeeping, trust and custody and reporting services for retirement savings plans, insurance companies, endowments and other financial institutions and other products. Fees and other revenues received for performance of asset management and administrative services are recognized as revenue when earned, typically when the service is performed. Fees for managing customers’ mandatory retirement savings accounts in Chile are collected with each monthly deposit made by our customers. If a customer stops contributing before retirement age, we collect no fees but services are still provided. We recognize revenue from these long-term service contracts as services are performed over the life of the contract.
Deferred Acquisition Costs - Policy	Deferred Acquisition Costs Incremental direct costs of contract acquisition as well as certain costs directly related to acquisition activities (underwriting, policy issuance and processing, medical and inspection and sales force contract selling) for the successful acquisition of new and renewal insurance policies and investment contract business are capitalized to the extent recoverable. Commissions and other incremental direct costs for the acquisition of long-term service contracts are also capitalized to the extent recoverable. Maintenance costs and acquisition costs that are not deferrable are charged to net income as incurred. DAC for universal life-type insurance contracts and certain investment contracts are amortized over the expected lifetime of the contracts in relation to EGPs or, in certain circumstances, estimated gross revenues (“EGR”). This amortization is adjusted in the current period when EGPs or EGRs are revised. EGRs include similar assumptions as the revenue component of EGPs and the changes of future estimates and reflection of actual experience and market conditions is done in the same manner as EGPs. For individual variable universal life insurance, individual variable annuities and group annuities that have separate account U.S. equity investment options, we utilize a mean reversion methodology (reversion to the mean assumption), a common industry practice, to determine the future domestic equity market growth rate assumption used for the calculation of EGPs. DAC for participating life insurance policies are amortized in proportion to estimated gross margins (“EGM”) rather than EGPs. EGMs include similar assumption items as EGPs. We stopped selling participating business in the early 2000s. Some products allow for underwritten death benefit increases and cost of living adjustments, resulting in a small amount of new DAC each year, and the amortization schedules are modified as appropriate. DAC for non-participating term life insurance and individual disability policies are amortized over the premium-paying period of the related policies using assumptions consistent with those used in computing policyholder liabilities. Once these assumptions are made for a given policy or group of policies, they will not be changed over the life of the policy unless a loss recognition event occurs. DAC on insurance policies and investment contracts are subject to recoverability testing at the time of policy issue and loss recognition testing on an annual basis, or when an event occurs that may warrant loss recognition. If loss recognition or impairment is necessary, DAC would be written off to the extent it is determined that future policy premiums and investment income or gross profits are not adequate to cover related losses and expenses. DAC on short-duration group benefits policies are amortized over the estimated term of the underlying contracts.
Deferred Acquisition Costs on Internal Replacements - Policy	Deferred Acquisition Costs on Internal Replacements All insurance and investment contract modifications and replacements are reviewed to determine if the internal replacement results in a substantially changed contract. If so, the acquisition costs, sales inducements and unearned revenue associated with the new contract are deferred and amortized over the lifetime of the new contract. In addition, the existing DAC, sales inducement costs and unearned revenue balances associated with the replaced contract are written off. If an internal replacement results in a substantially unchanged contract, the acquisition costs, sales inducements and unearned revenue associated with the new contract are immediately recognized in the period incurred. In addition, the existing DAC, sales inducement costs or unearned revenue balance associated with the replaced contract is not written off, but instead is carried over to the new contract.
Long-Term Debt - Policy	Long-Term Debt Long-term debt includes notes payable, nonrecourse mortgages and other debt with a maturity date greater than one year at the date of issuance. Current maturities of long-term debt are classified as long-term debt in our consolidated statements of financial position. Long-term debt is primarily recorded at the unpaid principal balance, net of unamortized discount, premium and issuance costs.
Reinsurance - Policy	Reinsurance We enter into reinsurance agreements with other companies in the normal course of business in order to limit losses and minimize exposure to significant risks. We may assume reinsurance from or cede reinsurance to other companies. Assets and liabilities related to reinsurance ceded are reported on a gross basis. Premiums and expenses are reported net of reinsurance ceded. The cost of reinsurance related to long-duration contracts is accounted for over the life of the underlying reinsured policies using assumptions consistent with those used to account for the underlying policies. We are contingently liable with respect to reinsurance ceded to other companies in the event the reinsurer is unable to meet the obligations it has assumed. As of December 31, 2020 and 2019, we had $1,095.3 million and $997.8 million of net ceded reinsurance recoverables, respectively, which does not reflect potentially offsetting impacts of collateral. The reinsurance recoverable is recognized in premiums due and other receivables on the consolidated statements of financial position. As of December 31, 2020 and 2019, $506.3 million, or 97%, and $457.2 million, or 98%, were with our five largest ceded reinsurers, respectively. The effects of reinsurance on premiums and other considerations and policy and contract benefits were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Premiums and other considerations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct ​ $ 6,645.4 ​ $ 8,428.1 ​ $ 6,928.3 ​ Assumed ​ ​ 1.7 ​ 1.6 ​ 1.7 ​ Ceded ​ ​ (609.7) ​ (563.1) ​ (520.4) ​ Net premiums and other considerations ​ $ 6,037.4 ​ $ 7,866.6 ​ $ 6,409.6 ​ Benefits, claims and settlement expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct ​ $ 8,788.3 ​ $ 10,463.6 ​ $ 8,667.7 ​ Assumed ​ ​ 21.8 ​ 23.1 ​ 24.9 ​ Ceded ​ ​ (528.6) ​ (580.9) ​ (500.1) ​ Net benefits, claims and settlement expenses ​ $ 8,281.5 ​ $ 9,905.8 ​ $ 8,192.5 ​ ​
Separate Accounts - Policy	Separate Accounts The separate accounts are legally segregated and are not subject to the claims that arise out of any of our other business. The client, rather than us, directs the investments and bears the investment risk of these funds. The separate account assets represent the fair value of funds that are separately administered by us for contracts with equity, real estate and fixed income investments and are presented as a summary total within the consolidated statements of financial position. An equivalent amount is reported as separate account liabilities, which represent the obligation to return the monies to the client. We receive fees for mortality, withdrawal and expense risks, as well as administrative, maintenance and investment advisory services that are included in the consolidated statements of operations. Net deposits, net investment income and realized and unrealized capital gains and losses of the separate accounts are not reflected in the consolidated statements of operations. Separate account assets and separate account liabilities include certain international retirement accumulation products where the segregated funds and associated obligation to the client are consolidated within our financial statements. We have determined that summary totals are the most meaningful presentation for these funds. As of December 31, 2020 and December 31, 2019, the separate accounts included a separate account valued at $80.4 million and $100.4 million, respectively, which primarily included shares of our stock that were allocated and issued to eligible participants of qualified employee benefit plans administered by us as part of the policy credits issued under our 2001 demutualization. These shares are included in both basic and diluted earnings per share calculations. In the consolidated statements of financial position, the separate account shares are recorded at fair value and are reported as separate account assets with a corresponding separate account liability. Changes in fair value of the separate account shares are reflected in both the separate account assets and separate account liabilities and do not impact our results of operations.
Income Taxes - Policy	Income Taxes We file a U.S. consolidated income tax return that includes all of our qualifying subsidiaries. In addition, we file income tax returns in all states and foreign jurisdictions in which we conduct business. Our policy of allocating income tax expenses and benefits to companies in the group is generally based upon pro rata contribution of taxable income or operating losses. We are taxed at corporate rates on taxable income based on existing tax laws. Current income taxes are charged or credited to net income based upon amounts estimated to be payable or recoverable as a result of taxable operations for the current year. Deferred income taxes are provided for the tax effect of temporary differences in the financial reporting and income tax bases of assets and liabilities, net operating loss carryforwards and tax credit carryforwards using enacted income tax rates and laws. The effect on deferred income tax assets and deferred income tax liabilities of a change in tax rates is recognized in net income in the period in which the change is enacted. Subsequent to a change in tax rates and laws, any stranded tax effects remaining in AOCI will be released only if an entire portfolio is liquidated, sold or extinguished. However, a specific exception to this rule was adopted effective January 1, 2018, to reclassify the stranded tax effects generated by U.S. tax reform from AOCI to retained earnings. Further details are included under the caption “Recent Accounting Pronouncements.”
Foreign Exchange - Policy	Foreign Exchange Assets and liabilities of our foreign subsidiaries and affiliates denominated in non-U.S. dollars, where the U.S. dollar is not the functional currency, are translated into U.S. dollar equivalents at the year-end spot foreign exchange rates. Resulting translation adjustments are reported as a component of stockholders' equity, along with any related hedge and tax effects. Revenues and expenses for these entities are translated at the average exchange rates. Revenue, expense and other foreign currency transaction and translation adjustments that affect cash flows are reported in net income, along with related hedge and tax effects.
Goodwill and Other Intangibles - Policy	Goodwill and Other Intangibles Goodwill and other intangible assets include the cost of acquired subsidiaries in excess of the fair value of the net tangible assets recorded in connection with acquisitions. Goodwill and indefinite-lived intangible assets are not amortized. Rather, they are tested for impairment during the third quarter each year, or more frequently if events or changes in circumstances indicate that the asset might be impaired. Goodwill is tested at the reporting unit level, which is the same level as or one level below the operating segment, if financial information is prepared and regularly reviewed by management at that level. Once goodwill has been assigned to a reporting unit, it is no longer associated with a particular acquisition; therefore, all of the activities within a reporting unit, whether acquired or organically grown, are available to support the goodwill value. Impairment testing for indefinite-lived intangible assets primarily consists of a qualitative assessment to determine if a quantitative assessment is needed for a comparison of the fair value of the intangible asset with its carrying value. Intangible assets with a finite useful life are amortized as related benefits emerge and are reviewed periodically for indicators of impairment in value. If facts and circumstances suggest possible impairment, the sum of the estimated undiscounted future cash flows expected to result from the use of the asset is compared to the current carrying value of the asset. If the undiscounted future cash flows are less than the carrying value, an impairment loss is recognized for the excess of the carrying amount of assets over their fair value.
Earnings Per Common Share - Policy	Earnings Per Common Share Basic earnings per common share is calculated by dividing net income available to common stockholders by the weighted-average number of common shares outstanding for the period and excludes the dilutive effect of equity awards. Diluted earnings per common share reflects the potential dilution that could occur if dilutive securities, such as options and non-vested stock grants, were exercised or resulted in the issuance of common stock.

Nature of Operations and Sign_3

Nature of Operations and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Nature of Operations and Significant Accounting Policies
Effects of Reinsurance on Premiums and Other Considerations and Policy and Contract Benefits (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Premiums and other considerations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct ​ $ 6,645.4 ​ $ 8,428.1 ​ $ 6,928.3 ​ Assumed ​ ​ 1.7 ​ 1.6 ​ 1.7 ​ Ceded ​ ​ (609.7) ​ (563.1) ​ (520.4) ​ Net premiums and other considerations ​ $ 6,037.4 ​ $ 7,866.6 ​ $ 6,409.6 ​ Benefits, claims and settlement expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct ​ $ 8,788.3 ​ $ 10,463.6 ​ $ 8,667.7 ​ Assumed ​ ​ 21.8 ​ 23.1 ​ 24.9 ​ Ceded ​ ​ (528.6) ​ (580.9) ​ (500.1) ​ Net benefits, claims and settlement expenses ​ $ 8,281.5 ​ $ 9,905.8 ​ $ 8,192.5 ​

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Other Intangible Assets
Goodwill (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement Principal ​ ​ U.S. ​ ​ ​ ​ ​ ​ and Income ​ Global ​ Principal ​ Insurance ​ ​ ​ ​ ​ ​ ​ ​ ​ Solutions ​ Investors ​ International ​ Solutions ​ Corporate ​ Consolidated ​ ​ ​ (in millions) ​ Balance as of January 1, 2019 ​ $ 57.4 ​ $ 307.3 ​ $ 676.6 ​ $ 56.6 ​ $ 2.1 ​ $ 1,100.0 ​ Goodwill from acquisitions (1) ​ ​ 618.5 ​ ​ 6.5 ​ ​ — ​ ​ — ​ ​ (1.1) ​ ​ 623.9 ​ Foreign currency ​ — ​ 1.5 ​ (31.6) ​ — ​ — ​ (30.1) ​ Other (2) ​ ​ — ​ ​ 2.2 ​ ​ (2.2) ​ ​ — ​ ​ — ​ ​ — ​ Balance as of December 31, 2019 ​ ​ 675.9 ​ ​ 317.5 ​ ​ 642.8 ​ ​ 56.6 ​ ​ 1.0 ​ ​ 1,693.8 ​ Foreign currency ​ ​ — ​ ​ 3.4 ​ ​ 13.8 ​ ​ — ​ ​ — ​ ​ 17.2 ​ Balance as of December 31, 2020 ​ $ 675.9 ​ $ 320.9 ​ $ 656.6 ​ $ 56.6 ​ $ 1.0 ​ $ 1,711.0 ​ (1) Relates to the acquisitions of: a) Wells Fargo Institutional Retirement & Trust business consolidated within our Retirement and Income Solutions segment; b) a consolidating interest in Finisterre Capital LLP within our Principal Global Investors segment for which we previously held an equity method interest; c) measurement period adjustments related to RobustWealth within our Principal Global Investors segment and Corporate segment. (2) Relates to the movement of our investment management company in Brazil from the Principal International segment to the Principal Global Investors segment.
Finite Lived Intangible Assets (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 2019 ​ ​ (in millions) ​ Gross carrying value ​ $ 1,338.2 ​ $ 1,346.3 ​ Accumulated amortization ​ 405.6 ​ ​ 343.2 ​ Net carrying value ​ $ 932.6 ​ $ 1,003.1 ​
Other Finite Lived Intangible Assets Estimated Amortization Expense (Table)	​ ​ ​ ​ ​ ​ Year ending December 31: ​ ​ 2021 ​ $ 75.1 ​ 2022 ​ ​ 73.9 ​ 2023 ​ ​ 71.2 ​ 2024 ​ ​ 70.0 ​ 2025 ​ ​ 68.2 ​

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2020
Variable Interest Entities
Carrying Amounts of Assets and Liabilities of Consolidated Variable Interest Entities (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ ​ Total ​ Total ​ Total ​ Total ​ ​ assets liabilities assets liabilities ​ ​ ​ (in millions) ​ Grantor trust (1) ​ $ — ​ $ — ​ $ 99.9 ​ $ 98.6 ​ Mandatory retirement savings funds (2) ​ 41,995.2 ​ 41,527.9 ​ 39,891.1 ​ 39,524.9 ​ Real estate (3) ​ 499.0 ​ 21.3 ​ 479.7 ​ 88.0 ​ Sponsored investment funds (4) ​ 419.5 ​ 3.2 ​ 331.4 ​ 2.2 ​ Residential mortgage loans (5) ​ ​ 319.8 ​ ​ — ​ ​ — ​ ​ — ​ Total ​ $ 43,233.5 ​ $ 41,552.4 ​ $ 40,802.1 ​ $ 39,713.7 ​ (1) The assets of the grantor trust were primarily fixed maturities, available-for-sale. The liabilities were primarily other liabilities that reflected an embedded derivative of the forecasted transaction to deliver the underlying securities. (2) The assets of the mandatory retirement savings funds primarily include separate account assets and equity securities. The liabilities primarily include separate account liabilities and contractholder funds. (3) The assets of the real estate VIEs primarily include real estate and cash. Liabilities primarily include other liabilities and included long-term debt as of December 31, 2019. (4) The assets of sponsored investment funds are primarily fixed maturities and equity securities, certain of which are reported with other investments, and cash. The consolidated statements of financial position included a $226.8 million and $215.4 million redeemable noncontrolling interest for sponsored investment funds as of December 31, 2020 and December 31, 2019, respectively. (5) The assets of the residential mortgage loans VIE primarily include residential mortgage loans. The liabilities of the VIE are eliminated in our consolidated results.
Asset Carrying Value and Maximum Loss Exposure of Unconsolidated Variable Interest Entities (Table)	​ ​ ​ ​ ​ Maximum exposure to ​ ​ Asset carrying value loss (1) ​ ​ (in millions) ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 296.9 ​ $ 285.7 ​ Residential mortgage-backed pass-through securities ​ ​ 2,986.8 ​ ​ 2,857.6 ​ Commercial mortgage-backed securities ​ ​ 4,942.3 ​ ​ 4,741.2 ​ Collateralized debt obligations (2) ​ 4,027.5 ​ 4,045.9 ​ Other debt obligations ​ 7,045.9 ​ 6,832.6 ​ Fixed maturities, trading: ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed pass-through securities ​ 190.5 ​ 190.5 ​ Commercial mortgage-backed securities ​ 27.1 ​ 27.1 ​ Collateralized debt obligations (2) ​ ​ 20.6 ​ ​ 20.6 ​ Other debt obligations ​ ​ 9.4 ​ ​ 9.4 ​ Equity securities ​ ​ 121.7 ​ ​ 121.7 ​ Other investments: ​ ​ ​ ​ ​ ​ ​ Other limited partnership and fund interests (3) ​ 999.1 ​ 1,739.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 238.2 ​ $ 225.7 ​ Residential mortgage-backed pass-through securities ​ ​ 2,982.4 ​ ​ 2,913.9 ​ Commercial mortgage-backed securities ​ ​ 4,850.2 ​ ​ 4,746.6 ​ Collateralized debt obligations (2) ​ 3,215.3 ​ 3,226.7 ​ Other debt obligations ​ 8,191.1 ​ 8,076.4 ​ Fixed maturities, trading: ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed pass-through securities ​ 282.3 ​ 282.3 ​ Commercial mortgage-backed securities ​ 28.2 ​ 28.2 ​ Collateralized debt obligations (2) ​ ​ 20.9 ​ ​ 20.9 ​ Other debt obligations ​ ​ 13.2 ​ ​ 13.2 ​ Equity securities ​ ​ 123.2 ​ ​ 123.2 ​ Other investments: ​ ​ ​ ​ ​ ​ ​ Other limited partnership and fund interests (3) ​ 911.9 ​ 1,467.0 ​ (1) Our risk of loss is limited to our initial investment measured at amortized cost for fixed maturities, available-for-sale. Our risk of loss is limited to our investment measured at fair value for our fixed maturities, trading and equity securities. Our risk of loss is limited to our carrying value plus any unfunded commitments and/or guarantees and similar provisions for our other investments. Unfunded commitments are not liabilities on our consolidated statements of financial position because we are only required to fund additional equity when called upon to do so by the general partner or investment manager . (2) Primarily consists of collateralized loan obligations backed by secured corporate loans. (3) As of December 31, 2020 and December 31, 2019, the maximum exposure to loss for other limited partnership and fund interests includes $141.2 million and $129.1 million, respectively, of debt within certain of our managed international real estate funds that is fully secured by assets whose value exceeds the amount of the debt, but also includes recourse to the investment manager.

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2020
Investments
Available-for-Sale Securities (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ Allowance ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ for credit ​ ​ ​ ​ cost (1) gains losses loss Fair value ​ ​ (in millions) ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 1,893.1 ​ $ 228.9 ​ $ 10.5 ​ $ — ​ $ 2,111.5 ​ Non-U.S. governments ​ 881.6 ​ 192.1 ​ — ​ — ​ 1,073.7 ​ States and political subdivisions ​ 8,004.9 ​ 1,175.5 ​ 12.6 ​ — ​ 9,167.8 ​ Corporate ​ 41,289.9 ​ 6,160.9 ​ 95.1 ​ 0.9 ​ 47,354.8 ​ Residential mortgage-backed pass-through securities ​ 2,857.6 ​ 129.4 ​ 0.2 ​ — ​ 2,986.8 ​ Commercial mortgage-backed securities ​ 4,741.2 ​ 241.3 ​ 35.9 ​ 4.3 ​ 4,942.3 ​ Collateralized debt obligations (2) ​ 4,045.9 ​ 8.7 ​ 24.9 ​ 2.2 ​ 4,027.5 ​ Other debt obligations ​ 6,832.6 ​ 243.2 ​ 29.9 ​ — ​ 7,045.9 ​ Total fixed maturities, available-for-sale ​ $ 70,546.8 ​ $ 8,380.0 ​ $ 209.1 ​ $ 7.4 ​ $ 78,710.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other-than- ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ temporary ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ ​ ​ ​ impairments in ​ ​ ​ cost ​ gains ​ losses ​ Fair value ​ OCI (3) ​ ​ ​ (in millions) ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 1,627.0 ​ $ 100.2 ​ $ 3.0 ​ $ 1,724.2 ​ $ — ​ Non-U.S. governments ​ 852.3 ​ 144.1 ​ 0.2 ​ 996.2 ​ — ​ States and political subdivisions ​ 6,857.1 ​ 644.5 ​ 11.6 ​ 7,490.0 ​ — ​ Corporate ​ 36,993.1 ​ 3,706.5 ​ 52.2 ​ 40,647.4 ​ — ​ Residential mortgage-backed pass-through securities ​ 2,913.9 ​ 72.3 ​ 3.8 ​ 2,982.4 ​ — ​ Commercial mortgage-backed securities ​ 4,746.6 ​ 127.6 ​ 24.0 ​ 4,850.2 ​ 15.8 ​ Collateralized debt obligations (2) ​ 3,226.7 ​ 2.9 ​ 14.3 ​ 3,215.3 ​ 0.9 ​ Other debt obligations ​ 8,085.8 ​ 129.6 ​ 14.9 ​ 8,200.5 ​ 31.7 ​ Total fixed maturities, available-for-sale ​ $ 65,302.5 ​ $ 4,927.7 ​ $ 124.0 ​ $ 70,106.2 ​ $ 48.4 ​ (1) Amortized cost excludes accrued interest receivable of $552.5 million as of December 31, 2020. (2) Primarily consists of collateralized loan obligations backed by secured corporate loans. (3) Excludes $62.3 million as of December 31, 2019, of net unrealized gains on impaired fixed maturities, available-for-sale related to changes in fair value subsequent to the impairment date, which are included in gross unrealized gains and gross unrealized losses.
Fixed Maturities Available-for-Sale by Contractual Maturity (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized cost Fair value ​ ​ (in millions) ​ Due in one year or less ​ $ 2,336.5 ​ $ 2,372.9 ​ Due after one year through five years ​ ​ 10,831.5 ​ ​ 11,570.0 ​ Due after five years through ten years ​ ​ 14,032.7 ​ ​ 15,601.5 ​ Due after ten years ​ ​ 24,868.8 ​ ​ 30,163.4 ​ Subtotal ​ ​ 52,069.5 ​ ​ 59,707.8 ​ Mortgage-backed and other asset-backed securities ​ ​ 18,477.3 ​ ​ 19,002.5 ​ Total ​ $ 70,546.8 ​ $ 78,710.3 ​ ​
Net Investment Income (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Fixed maturities, available-for-sale (1) ​ $ 2,660.5 ​ $ 2,606.0 ​ $ 2,479.9 ​ Fixed maturities, trading ​ ​ 18.7 ​ 23.8 ​ 26.4 ​ Equity securities ​ ​ 62.8 ​ ​ 110.5 ​ ​ 38.8 ​ Mortgage loans ​ ​ 724.7 ​ 707.0 ​ 641.4 ​ Real estate ​ ​ 180.8 ​ 191.1 ​ 158.8 ​ Policy loans ​ ​ 41.6 ​ 44.0 ​ 45.0 ​ Cash and cash equivalents ​ ​ 17.4 ​ 65.3 ​ 56.2 ​ Derivatives (1) ​ ​ (1.8) ​ (2.0) ​ 0.1 ​ Other ​ ​ 296.5 ​ 370.8 ​ 285.0 ​ Total ​ ​ 4,001.2 ​ 4,116.5 ​ 3,731.6 ​ Investment expenses ​ ​ (110.6) ​ (118.1) ​ (102.4) ​ Net investment income ​ $ 3,890.6 ​ $ 3,998.4 ​ $ 3,629.2 ​ (1) Upon adoption of authoritative guidance effective January 1, 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships are reported in net investment income with the earnings effect of fixed maturities, available-for-sale. Prior to 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships were reported in net realized capital gains (losses). See Note 5, Derivative Financial Instruments, for further details.
Net Realized Capital Gains and Losses (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross gains ​ $ 134.2 ​ $ 15.5 ​ $ 40.2 ​ Gross losses ​ ​ (48.5) ​ (15.3) ​ (74.8) ​ Net credit losses (1) ​ ​ (22.9) ​ (43.5) ​ (29.1) ​ Hedging, net (2) ​ ​ (9.7) ​ (9.3) ​ (39.6) ​ Fixed maturities, trading (3) ​ ​ 3.2 ​ 43.0 ​ (9.0) ​ Equity securities (4) ​ ​ 70.5 ​ ​ 84.5 ​ ​ (17.7) ​ Mortgage loans ​ ​ (15.5) ​ 3.0 ​ 6.2 ​ Derivatives (2) ​ ​ 77.3 ​ (120.3) ​ 11.7 ​ Other ​ ​ 114.0 ​ (10.4) ​ 36.7 ​ Net realized capital gains (losses) ​ $ 302.6 ​ $ (52.8) ​ $ (75.4) ​ (1) Upon adoption of authoritative guidance effective January 1, 2020, net credit losses include adjustments to the credit loss valuation allowance, write-offs and recoveries on available-for-sale securities. Prior to 2020, net credit losses included net other-than-temporary impairment losses and recoveries on available-for-sale securities. (2) Upon adoption of authoritative guidance effective January 1, 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships are reported in net investment income with the earnings effect of fixed maturities, available-for-sale. Prior to 2019, the change in fair value of fixed maturities, available-for-sale and the change in fair value of derivative hedging instruments in fair value hedging relationships were reported in net realized capital gains (losses). See Note 5, Derivative Financial Instruments, for further details. (3) Unrealized gains (losses) on fixed maturities, trading still held at the reporting date were $5.3 million, $32.8 million and $(12.2) million for the years ended December 31, 2020, 2019 and 2018, respectively. (4) Unrealized gains (losses) on equity securities still held at the reporting date were $64.6 million, $61.6 million and $(39.9) million for the years ended December 31, 2020, 2019 and 2018, respectively. This excludes $35.2 million, $66.9 million and $ 4.9 million of unrealized gains on equity securities still held at the reporting date for the years ended December 31, 2020, 2019 and 2018, respectively, that were reported in net investment income.
Allowance for credit loss (Tables)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ mortgage- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ backed ​ Commercial ​ Collateralized ​ ​ ​ ​ ​ ​ ​ ​ U.S. ​ ​ ​ ​ States and ​ ​ ​ ​ pass- ​ mortgage- ​ debt ​ Other ​ ​ ​ ​ ​ government ​ Non-U.S ​ political ​ ​ ​ ​ through ​ backed ​ obligations ​ debt ​ ​ ​ ​ ​ and agencies ​ governments ​ subdivisions ​ Corporate ​ securities ​ securities ​ (2) ​ obligations ​ Total ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning balance (1) ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — Additions for credit losses not previously recorded ​ ​ — ​ ​ — ​ ​ — ​ ​ 13.2 ​ ​ — ​ ​ 2.9 ​ ​ 0.1 ​ ​ — ​ ​ 16.2 Reductions for securities sold during the period ​ ​ — ​ ​ — ​ ​ — ​ ​ (7.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (7.0) Additional increases (decreases) for credit losses on securities with an allowance recorded in the previous period ​ ​ — ​ ​ — ​ ​ — ​ ​ (5.9) ​ ​ — ​ ​ 4.0 ​ ​ 2.1 ​ ​ — ​ ​ 0.2 Write-offs charged against allowance ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2.6) ​ ​ — ​ ​ — ​ ​ (2.6) Foreign currency translation adjustment ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.6 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.6 Ending balance ​ $ — ​ $ — ​ $ — ​ $ 0.9 ​ $ — ​ $ 4.3 ​ $ 2.2 ​ $ — ​ $ 7.4 (1) The allowance for credit loss associated with fixed maturities, available-for-sale was applied prospectively upon adoption of authoritative guidance effective January 1, 2020. (2) Primarily consists of collateralized loan obligations backed by secured corporate loans.
Other-Than-Temporary Impairment Losses, Net of Recoveries (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2019 2018 ​ ​ (in millions) Net realized capital losses, excluding impairment losses on available-for-sale securities ​ $ (9.3) ​ $ (46.3) Net other-than-temporary impairment (losses) recoveries on available-for-sale securities ​ (38.3) ​ 10.6 Other-than-temporary impairment losses on fixed maturities, available-for-sale ​ ​ ​ ​ reclassified from other comprehensive income (1) ​ ​ (5.2) ​ ​ (39.7) Net impairment losses on available-for-sale securities ​ (43.5) ​ (29.1) Net realized capital losses ​ $ (52.8) ​ $ (75.4) (1) Represents the net impact of (a) gains resulting from reclassification of noncredit impairment losses for fixed maturities with bifurcated OTTI from net realized capital gains (losses) to OCI and (b) losses resulting from reclassification of previously recognized noncredit impairment losses from OCI to net realized capital gains (losses) for fixed maturities with bifurcated OTTI that had additional credit losses or fixed maturities that previously had bifurcated OTTI that have now been sold or are intended to be sold.
Other-Than-Temporary Impairment, Credit Losses Recognized in Earnings (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2019 2018 ​ ​ (in millions) ​ Beginning balance ​ $ (117.5) ​ $ (124.3) ​ Credit losses for which an other-than-temporary impairment was not previously recognized ​ (6.8) ​ (11.3) ​ Credit losses for which an other-than-temporary impairment was previously recognized ​ (11.8) ​ (20.0) ​ Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold ​ 54.3 ​ 29.5 ​ Net reduction for positive changes in cash flows expected to be collected and amortization (1) ​ 0.8 ​ 8.6 ​ Ending balance ​ $ (81.0) ​ $ (117.5) ​ (1) Amounts are recognized in net investment income.
Available-for-Sale Securities in Unrealized Loss Positions Without an Allowance for Credit Loss (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Less than ​ Greater than or ​ ​ ​ ​ ​ twelve months equal to twelve months ​ Total ​ ​ ​ Gross ​ ​ Gross ​ ​ Gross ​ ​ Fair ​ unrealized ​ Fair ​ unrealized ​ Fair ​ unrealized ​ value losses value losses value losses ​ ​ (in millions) Fixed maturities, available-for-sale(1): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 351.1 ​ $ 10.4 ​ $ — ​ $ — ​ $ 351.1 ​ $ 10.4 States and political subdivisions ​ 363.5 ​ 12.5 ​ — ​ — ​ 363.5 ​ 12.5 Corporate ​ 1,578.7 ​ 54.4 ​ 267.9 ​ 40.6 ​ 1,846.6 ​ 95.0 Residential mortgage-backed pass- through securities ​ 92.3 ​ 0.2 ​ 1.6 ​ — ​ 93.9 ​ 0.2 Commercial mortgage-backed securities ​ 970.9 ​ 22.1 ​ 137.4 ​ 12.2 ​ 1,108.3 ​ 34.3 Collateralized debt obligations (2) ​ 1,750.6 ​ 11.1 ​ 931.1 ​ 12.9 ​ 2,681.7 ​ 24.0 Other debt obligations ​ 802.3 ​ 28.1 ​ 61.1 ​ 1.7 ​ 863.4 ​ 29.8 Total fixed maturities, available-for-sale ​ $ 5,909.4 ​ $ 138.8 ​ $ 1,399.1 ​ $ 67.4 ​ $ 7,308.5 ​ $ 206.2 (1) Fair value and gross unrealized losses are excluded for available-for-sale securities for which an allowance for credit loss has been recorded. (2) Primarily consists of collateralized loan obligations backed by secured corporate loans.
Gross Unrealized Losses for Fixed Maturities (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Less than ​ Greater than or ​ ​ ​ ​ ​ ​ ​ ​ twelve months equal to twelve months ​ Total ​ ​ ​ Gross ​ Gross ​ ​ Gross ​ ​ ​ Fair ​ unrealized ​ Fair ​ unrealized ​ Fair ​ unrealized ​ ​ ​ value ​ losses (2) value losses (2) value losses (2) ​ ​ (in millions) ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 100.0 ​ $ 1.9 ​ $ 74.2 ​ $ 1.1 ​ $ 174.2 ​ $ 3.0 ​ Non-U.S. governments ​ 17.6 ​ 0.2 ​ 12.4 ​ — ​ 30.0 ​ 0.2 ​ States and political subdivisions ​ 559.9 ​ 11.2 ​ 86.3 ​ 0.4 ​ 646.2 ​ 11.6 ​ Corporate ​ 1,041.5 ​ 27.8 ​ 394.7 ​ 24.4 ​ 1,436.2 ​ 52.2 ​ Residential mortgage-backed pass- through securities ​ 429.6 ​ 1.4 ​ 237.3 ​ 2.4 ​ 666.9 ​ 3.8 ​ Commercial mortgage-backed securities ​ 829.3 ​ 9.2 ​ 268.5 ​ 14.8 ​ 1,097.8 ​ 24.0 ​ Collateralized debt obligations (1) ​ 639.4 ​ 1.8 ​ 1,447.8 ​ 12.5 ​ 2,087.2 ​ 14.3 ​ Other debt obligations ​ 1,772.8 ​ 9.5 ​ 613.7 ​ 5.4 ​ 2,386.5 ​ 14.9 ​ Total fixed maturities, available-for-sale ​ $ 5,390.1 ​ $ 63.0 ​ $ 3,134.9 ​ $ 61.0 ​ $ 8,525.0 ​ $ 124.0 ​ (1) Primarily consists of collateralized loan obligations backed by secured corporate loans. (2) Prior to the implementation of authoritative guidance in 2020, other than temporary impairment losses reported in OCI were included with gross unrealized losses resulting in total gross unrealized losses for fixed maturities, available-for-sale being reported in the table.
Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Net unrealized gains on fixed maturities, available-for-sale (1) ​ $ 8,193.0 ​ $ 4,834.2 ​ Noncredit component of impairment losses on fixed maturities, available-for-sale (2) ​ ​ — ​ (48.4) ​ Net unrealized gains on derivative instruments ​ ​ 38.9 ​ 94.1 ​ Adjustments for assumed changes in amortization patterns ​ ​ (437.3) ​ (261.0) ​ Adjustments for assumed changes in policyholder liabilities ​ ​ (2,603.9) ​ (1,133.5) ​ Net unrealized gains on other investments and noncontrolling interest adjustments ​ ​ 78.0 ​ 96.8 ​ Provision for deferred income taxes ​ ​ (1,112.2) ​ (766.9) ​ Net unrealized gains on available-for-sale securities and derivative instruments ​ $ 4,156.5 ​ $ 2,815.3 ​ (1) Excludes net unrealized gains (losses) on fixed maturities, available-for-sale included in fair value hedging relationships. (2) Prior to the implementation of authoritative guidance in 2020, the noncredit component of impairment losses on fixed maturities, available-for-sale was included as a separate component of stockholders’ equity.
Financing Receivable Credit Quality Indicators (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 2017 2016 Prior Total ​ ​ ​ (in millions) Commercial mortgage ​ ​ ​ ​ ​ ​ ​ loans: ​ ​ ​ ​ ​ ​ ​ A- and above ​ $ 1,807.6 ​ $ 2,486.8 ​ $ 2,464.7 ​ $ 1,780.8 ​ $ 1,417.8 ​ $ 3,697.0 ​ $ 13,654.7 BBB+ thru BBB- ​ ​ 149.1 ​ ​ 194.1 ​ ​ 352.5 ​ ​ 262.7 ​ ​ 75.8 ​ ​ 499.7 ​ ​ 1,533.9 BB+ thru BB- ​ ​ 23.7 ​ ​ 69.0 ​ ​ — ​ ​ — ​ ​ 9.1 ​ ​ 43.9 ​ ​ 145.7 B+ and below ​ ​ 39.4 ​ ​ 20.0 ​ ​ — ​ ​ 5.8 ​ ​ 6.6 ​ ​ 35.5 ​ ​ 107.3 Total ​ $ 2,019.8 ​ $ 2,769.9 ​ $ 2,817.2 ​ $ 2,049.3 ​ $ 1,509.3 ​ $ 4,276.1 ​ $ 15,441.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct financing leases: ​ ​ ​ ​ ​ ​ ​ A- and above ​ $ 43.9 ​ $ 1.6 ​ $ 42.6 ​ $ 19.2 ​ $ 15.3 ​ $ 202.9 ​ $ 325.5 BBB+ thru BBB- ​ ​ 94.9 ​ ​ 5.5 ​ ​ 11.3 ​ ​ 18.4 ​ ​ 3.0 ​ ​ 35.5 ​ ​ 168.6 BB+ thru BB- ​ ​ 13.3 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 1.9 ​ ​ 15.2 B+ and below ​ ​ 57.6 ​ ​ 22.5 ​ ​ 11.9 ​ ​ — ​ ​ 1.0 ​ ​ 108.5 ​ ​ 201.5 Total ​ $ 209.7 ​ $ 29.6 ​ $ 65.8 ​ $ 37.6 ​ $ 19.3 ​ $ 348.8 ​ $ 710.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage ​ ​ ​ ​ ​ ​ ​ loans: ​ ​ ​ ​ ​ ​ ​ Performing ​ $ 699.1 ​ $ 336.7 ​ $ 167.0 ​ $ 165.1 ​ $ 167.6 ​ $ 398.7 ​ $ 1,934.2 Non-performing ​ ​ — ​ ​ 2.0 ​ ​ 0.8 ​ ​ 1.4 ​ ​ 0.4 ​ ​ 12.7 ​ ​ 17.3 Total ​ $ 699.1 ​ $ 338.7 ​ $ 167.8 ​ $ 166.5 ​ $ 168.0 ​ $ 411.4 ​ $ 1,951.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reinsurance recoverables ​ ​ ​ ​ ​ ​ $ 1,098.0 ​
Commercial Mortgage Loan Portfolio by Credit Risk (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 (1) ​ ​ Brick and mortar Credit tenant loans Total ​ ​ (in millions) ​ A- and above ​ $ 13,885.2 ​ $ 76.7 ​ $ 13,961.9 ​ BBB+ thru BBB- ​ 943.1 ​ 83.8 ​ 1,026.9 ​ BB+ thru BB- ​ 23.3 ​ — ​ 23.3 ​ B+ and below ​ 5.1 ​ — ​ 5.1 ​ Total ​ $ 14,856.7 ​ $ 160.5 ​ $ 15,017.2 ​ (1) Prior to the implementation of authoritative guidance in 2020, commercial mortgage loan credit quality disclosures included information about classes of those mortgages and information by vintage was excluded. Beginning in 2020, we determined that total commercial mortgage loans by credit risk and vintage is the most meaningful presentation.
Performing and Non-Performing Residential Mortgage Loans (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 (1) ​ ​ First liens Home equity Total ​ ​ (in millions) ​ Performing ​ $ 1,474.2 ​ $ 8.0 ​ $ 1,482.2 ​ Non-performing ​ 11.5 ​ 3.0 ​ 14.5 ​ Total ​ $ 1,485.7 ​ $ 11.0 ​ $ 1,496.7 ​ (1) Prior to the implementation of authoritative guidance in 2020, residential mortgage loan credit quality disclosures included information about classes of those mortgages and information by vintage was excluded. Beginning in 2020, we determined that total residential mortgage loans by credit risk and vintage is the most meaningful presentation.
Non-Accrual Financing Receivables (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Amortized cost ​ ​ Beginning ​ Ending ​ of nonaccrual ​ ​ amortized cost ​ amortized cost ​ assets without ​ ​ on nonaccrual ​ on nonaccrual ​ a valuation ​ ​ status ​ status ​ allowance ​ (in millions) Commercial mortgage loans ​ $ 5.0 ​ $ 10.7 ​ $ — Residential mortgage loans ​ ​ 6.8 ​ ​ 10.8 ​ ​ 0.7 Total ​ $ 11.8 ​ $ 21.5 ​ $ 0.7 ​ ​ ​ ​ ​ ​ ​ December 31, 2019 (1) ​ ​ (in millions) ​ Residential: ​ ​ ​ ​ First liens ​ $ 8.8 ​ Home equity ​ ​ 3.0 ​ Total ​ $ 11.8 ​ (1) Prior to the implementation of authoritative guidance in 2020, commercial and residential mortgage loan non-accrual disclosures included information about classes of those mortgages. Beginning in 2020, we determined that total commercial and residential mortgage loans on non-accrual status is the most meaningful presentation.
Financing Receivables Aging (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ cost ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 days or ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 days or ​ ​ ​ 30-59 days ​ 60-89 days ​ more past ​ Total ​ ​ ​ ​ ​ ​ ​ more and ​ ​ past due past due due past due Current Total (1) accruing ​ ​ (in millions) ​ Commercial mortgage loans ​ $ 42.1 ​ $ 9.2 ​ $ 12.0 ​ $ 63.3 ​ $ 15,378.3 ​ $ 15,441.6 ​ $ 1.3 ​ Direct financing leases ​ ​ — ​ ​ 3.2 ​ ​ — ​ ​ 3.2 ​ ​ 707.6 ​ ​ 710.8 ​ ​ — ​ Residential mortgage loans ​ ​ 66.6 ​ ​ 8.8 ​ ​ 10.9 ​ ​ 86.3 ​ ​ 1,865.2 ​ ​ 1,951.5 ​ ​ 6.5 ​ Total ​ $ 108.7 ​ $ 21.2 ​ $ 22.9 ​ $ 152.8 ​ $ 17,951.1 ​ $ 18,103.9 ​ $ 7.8 ​ (1) No reinsurance recoverables were considered past due as of December 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ investment ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 days or ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 days or ​ ​ ​ 30-59 days ​ 60-89 days ​ more past ​ Total ​ ​ ​ ​ ​ ​ ​ more and ​ ​ past due past due due past due Current Total loans accruing ​ ​ (in millions) ​ Commercial-brick and mortar ​ $ — ​ $ — ​ $ — ​ $ — ​ $ 14,856.7 ​ $ 14,856.7 ​ $ — ​ Commercial-credit tenant loans ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 160.5 ​ ​ 160.5 ​ ​ — ​ Residential-first liens ​ ​ 46.6 ​ ​ 9.3 ​ ​ 11.2 ​ ​ 67.1 ​ ​ 1,418.6 ​ ​ 1,485.7 ​ ​ 2.7 ​ Residential-home equity ​ ​ 0.8 ​ ​ — ​ ​ 0.3 ​ ​ 1.1 ​ ​ 9.9 ​ ​ 11.0 ​ ​ — ​ Total ​ $ 47.4 ​ $ 9.3 ​ $ 11.5 ​ $ 68.2 ​ $ 16,445.7 ​ $ 16,513.9 ​ $ 2.7 ​ (1) Prior to the implementation of authoritative guidance in 2020, commercial and residential mortgage loan past due disclosures included information about classes of those mortgages. Beginning in 2020, we determined that aging for total commercial and residential mortgage loans is the most meaningful presentation.
Financing Receivables Valuation Allowance (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ Direct ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ financing ​ Residential ​ Reinsurance ​ Other ​ ​ ​ ​ mortgage loans leases mortgage loans recoverables receivables Total ​ ​ (in millions) Beginning balance (1) ​ $ 27.3 ​ $ — ​ $ 3.3 ​ $ 2.5 ​ $ — ​ $ 33.1 Provision (2) ​ ​ 15.5 ​ ​ 0.1 ​ ​ 1.5 ​ ​ 0.2 ​ ​ — ​ ​ 17.3 Charge-offs ​ ​ — ​ ​ — ​ ​ (0.9) ​ ​ — ​ ​ — ​ ​ (0.9) Recoveries ​ ​ — ​ ​ — ​ ​ 2.8 ​ ​ — ​ ​ — ​ ​ 2.8 Foreign currency translation adjustment ​ ​ 0.4 ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ — ​ ​ 0.6 Ending balance ​ $ 43.2 ​ $ 0.1 ​ $ 6.9 ​ $ 2.7 ​ $ — ​ $ 52.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Residential Total ​ ​ (in millions) ​ For the year ended December 31, 2019 (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning balance ​ $ 24.3 ​ $ 3.1 ​ $ 27.4 ​ Provision ​ 0.2 ​ (3.2) ​ (3.0) ​ Charge-offs ​ — ​ (0.6) ​ (0.6) ​ Recoveries ​ — ​ 3.2 ​ 3.2 ​ Ending balance ​ $ 24.5 ​ $ 2.5 ​ $ 27.0 ​ Allowance ending balance by basis of impairment method: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ — ​ $ 1.4 ​ $ 1.4 ​ Collectively evaluated for impairment ​ 24.5 ​ 1.1 ​ 25.6 ​ Allowance ending balance ​ $ 24.5 ​ $ 2.5 ​ $ 27.0 ​ Loan balance by basis of impairment method: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ — ​ $ 11.4 ​ $ 11.4 ​ Collectively evaluated for impairment ​ 15,017.2 ​ 1,485.3 ​ 16,502.5 ​ Loan ending balance ​ $ 15,017.2 ​ $ 1,496.7 ​ $ 16,513.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning balance ​ $ 25.8 ​ $ 6.9 ​ $ 32.7 ​ Provision ​ (1.5) ​ (4.5) ​ (6.0) ​ Charge-offs ​ — ​ (2.4) ​ (2.4) ​ Recoveries ​ — ​ 3.1 ​ 3.1 ​ Ending balance ​ $ 24.3 ​ $ 3.1 ​ $ 27.4 ​ Allowance ending balance by basis of impairment method: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ — ​ $ 1.4 ​ $ 1.4 ​ Collectively evaluated for impairment ​ 24.3 ​ 1.7 ​ 26.0 ​ Allowance ending balance ​ $ 24.3 ​ $ 3.1 ​ $ 27.4 ​ Loan balance by basis of impairment method: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individually evaluated for impairment ​ $ — ​ $ 9.2 ​ $ 9.2 ​ Collectively evaluated for impairment ​ 13,996.3 ​ 1,358.8 ​ 15,355.1 ​ Loan ending balance ​ $ 13,996.3 ​ $ 1,368.0 ​ $ 15,364.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Upon adoption of authoritative guidance effective January 1, 2020, we updated accounting policies and methodology, adjusted the commercial and residential mortgage loan valuation allowance and established a valuation allowance for reinsurance recoverables. See Note 1, Nature of Operations and Significant Accounting Policies under the caption, “Recent Accounting Pronouncements” for further details. (2) During the year ended December 31, 2020, the outbreak of COVID-19 adversely impacted global economic activity and contributed to significant volatility in financial markets. As a result, certain current and forecasted environmental factors management believes to be relevant were adjusted, resulting in an increase in the valuation allowance for commercial and residential mortgage loans and direct financing leases. (3) Prior to the implementation of authoritative guidance in 2020, only commercial and residential mortgage loans were included in the allowance rollforward and the allowance was based on either individual or collective evaluation.
Mortgage Loans Purchased and Sold (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (in millions) Commercial mortgage loans: ​ ​ ​ Purchased ​ $ 166.8 ​ $ 200.5 ​ $ 127.5 Sold ​ 7.6 ​ 1.6 ​ 2.2 Residential mortgage loans: ​ ​ ​ Purchased(1) ​ 1,151.1 ​ 489.2 ​ 394.2 Sold ​ 117.4 ​ 70.7 ​ 80.3 (1) Includes mortgage loans purchased by a residential mortgage loan VIE established in 2020.
Commercial Mortgage Loans by Geographic Distribution and Property Type Distribution (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ December 31, 2019 ​ ​ Amortized ​ Percent ​ Amortized ​ Percent ​ ​ cost ​ of total ​ cost ​ of total ​ ​ ($ in millions) Geographic distribution ​ ​ ​ New England ​ $ 593.9 3.8 % $ 613.9 4.1 % Middle Atlantic ​ 4,438.2 28.8 ​ 4,139.7 27.5 ​ East North Central ​ 572.6 3.7 ​ 624.5 4.2 ​ West North Central ​ 267.5 1.7 ​ 237.2 1.6 ​ South Atlantic ​ 2,368.9 15.3 ​ 2,318.4 15.4 ​ East South Central ​ 316.6 2.1 ​ 438.5 2.9 ​ West South Central ​ 1,315.9 8.5 ​ 1,450.0 9.7 ​ Mountain ​ 936.2 6.1 ​ 931.8 6.2 ​ Pacific ​ 4,183.0 27.1 ​ 3,963.7 26.4 ​ International ​ 448.8 2.9 ​ 299.5 2.0 ​ Total ​ $ 15,441.6 100.0 % $ 15,017.2 100.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property type distribution ​ ​ ​ Office ​ $ 4,491.7 29.0 % $ 4,887.1 32.6 % Retail ​ 1,815.3 11.8 ​ 2,052.6 13.7 ​ Industrial ​ 2,488.7 16.1 ​ 2,268.5 15.1 ​ Apartments ​ 5,958.0 38.6 ​ 5,246.9 34.9 ​ Hotel ​ 89.4 0.6 ​ 90.8 0.6 ​ Mixed use/other ​ 598.5 3.9 ​ 471.3 3.1 ​ Total ​ $ 15,441.6 100.0 % $ 15,017.2 100.0 %
Minority Interests in Unconsolidated Entities-Balance Sheet (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 2019 ​ ​ ​ (in millions) ​ Total assets ​ $ 155,724.1 ​ $ 158,439.7 ​ Total liabilities ​ ​ 73,438.2 ​ 88,455.8 ​ Total equity ​ $ 82,285.9 ​ $ 69,983.9 ​ Net investment in unconsolidated entities (1) ​ $ 1,912.9 ​ $ 1,825.5 ​
Minority Interests in Unconsolidated Entities-Income Statement (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended ​ ​ ​ December 31, ​ ​ 2020 2019 2018 ​ ​ ​ (in millions) ​ Total revenues ​ $ 14,989.0 ​ $ 17,802.2 ​ $ 15,389.4 ​ Net income ​ ​ 7,757.0 ​ 7,938.3 ​ 6,542.1 ​ Our share of net income of unconsolidated entities (1) ​ ​ 143.9 ​ 222.5 ​ 161.6 ​ (1) Our most significant equity investee is Brasilprev Seguros e Previdencia, a co-managed joint venture in Brazil.
Financial Assets Subject to Netting Agreements (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross amounts not offset in the ​ ​ ​ ​ ​ ​ ​ ​ ​ consolidated statements ​ ​ ​ ​ ​ ​ ​ ​ ​ of financial position ​ ​ ​ ​ ​ Gross amount ​ ​ ​ ​ ​ ​ ​ of recognized ​ Financial ​ Collateral ​ ​ ​ ​ assets (1) instruments (2) received Net amount ​ ​ (in millions) ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative assets ​ $ 463.5 ​ $ (132.5) ​ $ (293.5) ​ $ 37.5 ​ Reverse repurchase agreements ​ 63.7 ​ — ​ (63.7) ​ — ​ Total ​ $ 527.2 ​ $ (132.5) ​ $ (357.2) ​ $ 37.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative assets ​ $ 288.7 ​ $ (88.4) ​ $ (197.6) ​ $ 2.7 ​ Reverse repurchase agreements ​ 23.6 ​ — ​ (23.6) ​ — ​ Total ​ $ 312.3 ​ $ (88.4) ​ $ (221.2) ​ $ 2.7 ​ (1) The gross amount of recognized derivative and reverse repurchase agreement assets are reported with other investments and cash and cash equivalents, respectively, on the consolidated statements of financial position. The above excludes $0.0 million and $6.0 million of derivative assets as of December 31, 2020 and December 31, 2019, respectively, that are not subject to master netting agreements or similar agreements. The gross amounts of derivative and reverse repurchase agreement assets are not netted against offsetting liabilities for presentation on the consolidated statements of financial position. (2) Represents amount of offsetting derivative liabilities that are subject to an enforceable master netting agreement or similar agreement that are not netted against the gross derivative assets for presentation on the consolidated statements of financial position.
Financial Liabilities Subject to Netting Agreements (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross amounts not offset in the ​ ​ ​ ​ ​ ​ ​ ​ ​ consolidated statements ​ ​ ​ ​ ​ ​ ​ ​ ​ of financial position ​ ​ ​ ​ ​ Gross amount ​ ​ ​ ​ ​ ​ ​ ​ of recognized ​ Financial ​ Collateral ​ ​ ​ ​ ​ liabilities (1) instruments (2) pledged Net amount ​ ​ (in millions) ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative liabilities ​ $ 186.2 ​ $ (132.5) ​ $ (45.7) ​ $ 8.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative liabilities ​ $ 216.0 ​ $ (88.4) ​ $ (118.3) ​ $ 9.3 ​ (1) The gross amount of recognized derivative liabilities is reported with other liabilities on the consolidated statements of financial position. The above excludes $467.8 million and $314.5 million of derivative liabilities as of December 31, 2020 and December 31, 2019, respectively, which are primarily embedded derivatives that are not subject to master netting agreements or similar agreements. The gross amounts of derivative liabilities are not netted against offsetting assets for presentation on the consolidated statements of financial position. (2) Represents amount of offsetting derivative assets that are subject to an enforceable master netting agreement or similar agreement that are not netted against the gross derivative liabilities for presentation on the consolidated statements of financial position.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Financial Instruments
Derivative Financial Instruments, Exposure (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ ​ (in millions) ​ Notional amounts of derivative instruments ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Interest rate swaps ​ $ 44,472.1 ​ $ 35,173.6 ​ Interest rate options ​ ​ 2,083.9 ​ 1,416.9 ​ Interest rate forwards ​ ​ 1,000.0 ​ ​ — ​ Interest rate futures ​ ​ 188.5 ​ 142.5 ​ Swaptions ​ ​ 62.0 ​ 62.0 ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ Currency forwards ​ ​ 1,115.8 ​ 1,182.3 ​ Currency swaps ​ ​ 1,045.5 ​ 1,027.2 ​ Currency options ​ ​ — ​ ​ 53.8 ​ Equity contracts: ​ ​ ​ ​ ​ ​ ​ Equity options ​ ​ 1,857.8 ​ 1,672.8 ​ Equity futures ​ ​ 218.1 ​ 149.5 ​ Credit contracts: ​ ​ ​ ​ ​ ​ ​ Credit default swaps ​ ​ 295.0 ​ 165.0 ​ Other contracts: ​ ​ ​ ​ ​ ​ ​ Embedded derivatives ​ ​ 9,953.8 ​ 9,742.3 ​ Total notional amounts at end of period ​ $ 62,292.5 ​ $ 50,787.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit exposure of derivative instruments ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Interest rate swaps ​ $ 291.0 ​ $ 181.9 ​ Interest rate options ​ ​ 51.0 ​ 28.3 ​ Interest rate forwards ​ ​ 6.2 ​ ​ — ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ Currency swaps ​ ​ 43.3 ​ 55.4 ​ Currency forwards ​ ​ 45.4 ​ 4.9 ​ Currency options ​ ​ — ​ ​ 0.1 ​ Equity contracts: ​ ​ ​ ​ ​ ​ ​ Equity options ​ ​ 33.2 ​ 30.5 ​ Credit contracts: ​ ​ ​ ​ ​ ​ ​ Credit default swaps ​ ​ 3.4 ​ 0.5 ​ Total gross credit exposure ​ ​ 473.5 ​ 301.6 ​ Less: collateral received ​ ​ 294.7 ​ 208.3 ​ Net credit exposure ​ $ 178.8 ​ $ 93.3 ​ ​ ​
Derivative Financial Instruments, Fair Value Disclosures (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative assets (1) ​ Derivative liabilities (2) ​ ​ December 31, 2020 December 31, 2019 December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Derivatives designated as hedging instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ $ — ​ $ — ​ $ 27.8 ​ $ 21.3 ​ Foreign exchange contracts ​ ​ 21.1 ​ 30.0 ​ ​ 44.7 ​ 15.2 ​ Total derivatives designated as hedging instruments ​ $ 21.1 ​ $ 30.0 ​ $ 72.5 ​ $ 36.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives not designated as hedging instruments ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts ​ $ 339.3 ​ $ 204.2 ​ $ 33.0 ​ $ 16.7 ​ Foreign exchange contracts ​ ​ 66.5 ​ 29.5 ​ ​ 29.2 ​ 100.2 ​ Equity contracts ​ ​ 33.2 ​ 30.5 ​ ​ 49.0 ​ 63.1 ​ Credit contracts ​ ​ 3.4 ​ 0.5 ​ ​ 2.5 ​ 1.2 ​ Other contracts ​ ​ — ​ — ​ ​ 467.8 ​ 312.8 ​ Total derivatives not designated as hedging instruments ​ ​ 442.4 ​ 264.7 ​ ​ 581.5 ​ 494.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total derivative instruments ​ $ 463.5 ​ $ 294.7 ​ $ 654.0 ​ $ 530.5 ​ (1) The fair value of derivative assets is reported with other investments on the consolidated statements of financial position. (2) The fair value of derivative liabilities is reported with other liabilities on the consolidated statements of financial position, with the exception of certain embedded derivative liabilities. Embedded derivatives with a net liability fair value of $467.8 million and $214.2 million as of December 31, 2020 and December 31, 2019, respectively, are reported with contractholder funds on the consolidated statements of financial position.
Credit Derivatives Sold (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ Maximum ​ average ​ ​ ​ Notional ​ Fair ​ future ​ expected life ​ ​ amount value payments (in years) ​ ​ ​ (in millions) ​ Single name credit default swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A ​ $ 20.0 ​ $ 0.5 ​ $ 20.0 4.5 ​ BBB ​ 115.0 ​ 2.1 ​ 115.0 3.9 ​ Sovereign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A ​ ​ 20.0 ​ ​ 0.6 ​ ​ 20.0 ​ 4.5 ​ BBB ​ ​ 15.0 ​ ​ 0.1 ​ ​ 15.0 ​ 1.0 ​ Total credit default swap protection sold ​ $ 170.0 ​ $ 3.3 ​ $ 170.0 3.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ ​ ​ ​ Maximum ​ average ​ ​ ​ Notional ​ Fair ​ future ​ expected life ​ ​ amount value payments (in years) ​ ​ ​ (in millions) ​ Single name credit default swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt ​ ​ ​ ​ ​ ​ ​ ​ ​ A ​ $ 5.0 ​ $ — ​ $ 5.0 0.5 ​ BBB ​ 70.0 ​ 0.2 ​ 70.0 2.6 ​ Sovereign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ BBB ​ ​ 15.0 ​ ​ 0.3 ​ ​ 15.0 ​ 2.0 ​ Total credit default swap protection sold ​ $ 90.0 ​ $ 0.5 ​ $ 90.0 2.4 ​
Fair Value Hedges (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative amount of fair ​ ​ ​ ​ ​ ​ ​ ​ ​ value hedging basis adjustment ​ Line item in the consolidated statements ​ ​ ​ ​ ​ ​ ​ included in the amortized cost ​ of financial position in which the ​ Amortized cost of hedged item ​ of the hedged item ​ hedged item is included December 31, 2020 December 31, 2019 December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Active hedging relationships ​ $ 476.1 ​ $ 142.0 ​ $ 21.4 ​ $ 18.1 ​ Discontinued hedging relationships ​ ​ 135.1 ​ ​ 159.3 ​ ​ 5.2 ​ ​ 7.7 ​ Total fixed maturities, available-for-sale in active or discontinued hedging relationships ​ $ 611.2 ​ $ 301.3 ​ $ 26.6 ​ $ 25.8 ​
Cash Flow Hedges (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in AOCI on derivatives ​ Derivatives in cash flow ​ ​ ​ for the year ended December 31, ​ hedging relationships Related hedged item 2020 2019 2018 ​ ​ ​ ​ (in millions) ​ Interest rate contracts ​ Fixed maturities, available-for-sale ​ $ (3.0) ​ $ (9.9) ​ $ 36.7 ​ Foreign exchange contracts ​ Fixed maturities, available-for-sale ​ ​ (37.1) ​ (9.4) ​ 20.8 ​ Foreign exchange contracts ​ Investment contracts ​ ​ — ​ — ​ (0.1) ​ Total ​ ​ ​ $ (40.1) ​ $ (19.3) ​ $ 57.4 ​
Effect of Fair Value and Cash Flow Hedges on Consolidated Statements of Operations (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ Benefits, ​ ​ ​ ​ ​ Net investment ​ Net realized ​ claims and ​ ​ ​ ​ ​ income related ​ capital gains ​ settlement ​ ​ ​ ​ ​ to hedges ​ related to ​ expenses ​ ​ ​ ​ ​ of fixed ​ hedges of fixed ​ related to ​ Operating ​ ​ maturities, ​ maturities, ​ hedges of ​ expenses ​ ​ available- ​ available- ​ investment ​ related to ​ for-sale for-sale contracts hedges of debt ​ ​ (in millions) Total amounts of consolidated statement of operations line items in which the effects of fair value and cash flow hedges are reported ​ $ 3,890.6 ​ $ 302.6 ​ $ 8,281.5 ​ $ 4,646.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses on fair value hedging relationships: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain recognized on hedged item ​ $ 3.3 ​ $ — ​ $ — ​ $ — ​ Loss recognized on derivatives ​ (3.8) ​ — ​ — ​ — ​ Amortization of hedged item basis adjustments ​ (2.5) ​ — ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ (6.2) ​ — ​ — ​ — ​ Total loss recognized for fair value hedging relationships ​ $ (9.2) ​ $ — ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gains (losses) on cash flow hedging relationships: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (loss) reclassified from AOCI on derivatives ​ $ 18.1 ​ $ 2.7 ​ $ (0.1) ​ $ — ​ Gain reclassified from AOCI as a result that a forecasted transaction is no longer probable of occurring ​ — ​ 0.1 ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain reclassified from AOCI on derivatives ​ — ​ 6.3 ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ 8.2 ​ — ​ — ​ — ​ Total gain (loss) recognized for cash flow hedging relationships ​ $ 26.3 ​ $ 9.1 ​ $ (0.1) ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Benefits, ​ ​ ​ ​ ​ Net investment ​ Net realized ​ claims and ​ ​ ​ ​ ​ income related ​ capital gains ​ settlement ​ ​ ​ ​ ​ to hedges ​ (losses) related to ​ expenses ​ ​ ​ ​ ​ of fixed ​ hedges of fixed ​ related to ​ Operating ​ ​ maturities, ​ maturities, ​ hedges of ​ expenses ​ ​ available- ​ available- ​ investment ​ related to ​ for-sale for-sale contracts hedges of debt ​ ​ (in millions) Total amounts of consolidated statement of operations line items in which the effects of fair value and cash flow hedges are reported ​ $ 3,998.4 ​ $ (52.8) ​ $ 9,905.8 ​ $ 4,503.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses on fair value hedging relationships: ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Gain recognized on hedged item ​ $ 5.7 ​ $ — ​ $ — ​ $ — ​ Loss recognized on derivatives ​ (6.0) ​ — ​ — ​ — ​ Amortization of hedged item basis adjustments ​ (4.2) ​ — ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ (3.4) ​ — ​ — ​ — ​ Total loss recognized for fair value hedging relationships ​ $ (7.9) ​ $ — ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gains (losses) on cash flow hedging relationships: ​ ​ ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ ​ ​ Gain (loss) reclassified from AOCI on derivatives ​ $ 19.8 ​ $ (0.6) ​ $ (0.1) ​ $ (4.8) ​ Gain reclassified from AOCI as a result that a forecasted transaction is no longer probable of occurring ​ — ​ 0.1 ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange contracts: ​ ​ ​ ​ ​ ​ ​ Gain reclassified from AOCI on derivatives ​ — ​ 9.5 ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ 7.4 ​ — ​ — ​ — ​ Total gain (loss) recognized for cash flow hedging relationships ​ $ 27.2 ​ $ 9.0 ​ $ (0.1) ​ $ (4.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ Net ​ Net realized ​ ​ ​ ​ ​ ​ ​ ​ investment ​ capital ​ Benefits, ​ ​ ​ ​ ​ income ​ gains (losses) ​ claims and ​ ​ ​ ​ ​ related ​ related to ​ settlement ​ ​ ​ ​ ​ to hedges ​ hedges ​ expenses ​ Operating ​ ​ of fixed ​ of fixed ​ related to ​ expenses ​ ​ maturities, ​ maturities, ​ hedges of ​ related to ​ ​ available- ​ available- ​ investment ​ hedges ​ for-sale for-sale contracts of debt ​ ​ (in millions) Total amounts of consolidated statement of operations line items in which the effects of fair value and cash flow hedges are reported ​ $ 3,629.2 ​ $ (75.4) ​ $ 8,192.5 ​ $ 4,136.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses on fair value hedging relationships: ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ Loss recognized on hedged item ​ $ — ​ $ (6.6) ​ $ — ​ $ — ​ Gain recognized on derivatives ​ — ​ 6.2 ​ — ​ — ​ Amortization of hedged item basis adjustments ​ (6.7) ​ — ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ (5.9) ​ — ​ — ​ — ​ Total loss recognized for fair value hedging relationships ​ $ (12.6) ​ $ (0.4) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gains (losses) on cash flow hedging relationships: ​ ​ ​ ​ ​ Interest rate contracts: ​ ​ ​ ​ ​ Gain (loss) reclassified from AOCI on derivatives ​ $ 20.9 ​ $ 17.0 ​ $ (0.1) ​ $ (10.7) ​ Gain reclassified from AOCI as a result that a forecasted transaction is no longer probable of occurring ​ — ​ 0.3 ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange contracts: ​ ​ ​ ​ ​ Gain reclassified from AOCI on derivatives ​ — ​ 12.7 ​ — ​ — ​ Amounts related to periodic settlements on derivatives ​ 6.0 ​ — ​ (0.1) ​ — ​ Total gain (loss) recognized for cash flow hedging relationships ​ $ 26.9 ​ $ 30.0 ​ $ (0.2) ​ $ (10.7) ​
Net Investment Hedges (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain recognized ​ ​ in AOCI on derivatives for the year ended ​ ​ December 31, Derivatives in net investment hedging relationships 2020 2019 2018 ​ ​ (in millions) Foreign exchange contracts ​ $ 7.9 ​ $ — ​ $ — Total ​ $ 7.9 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain reclassified from AOCI into ​ ​ net realized capital gains (losses) ​ ​ for the year ended December 31, Derivatives in net investment hedging relationships 2020 2019 2018 ​ ​ (in millions) Foreign exchange contracts ​ $ (7.1) ​ $ — ​ $ — Total ​ $ (7.1) ​ $ — ​ $ —
Derivatives Not Designated as Hedging Instruments (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in ​ ​ ​ net income on derivatives for the ​ ​ ​ year ended December 31, ​ Derivatives not designated as hedging instruments 2020 2019 2018 ​ ​ (in millions) ​ Interest rate contracts ​ $ 346.5 ​ $ 218.0 ​ $ (27.6) ​ Foreign exchange contracts ​ ​ 54.7 ​ (58.6) ​ (64.2) ​ Equity contracts ​ ​ (96.6) ​ (132.9) ​ (31.0) ​ Credit contracts ​ ​ 1.8 ​ (3.6) ​ (1.6) ​ Other contracts ​ ​ (255.5) ​ (168.1) ​ 108.5 ​ Total ​ $ 50.9 ​ $ (145.2) ​ $ (15.9) ​

Closed Block (Tables)

Closed Block (Tables)	12 Months Ended
	Dec. 31, 2020
Closed Block
Closed Block Liabilities and Assets Designated to the Closed Block (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) Closed Block liabilities ​ ​ ​ ​ ​ ​ ​ Future policy benefits and claims ​ $ 3,423.2 ​ $ 3,563.1 ​ Other policyholder funds ​ ​ 6.0 ​ 6.6 ​ Policyholder dividends payable ​ ​ 189.0 ​ 199.1 ​ Policyholder dividends obligation ​ ​ 298.2 ​ 202.7 ​ Other liabilities ​ ​ 8.7 ​ 7.8 ​ Total Closed Block liabilities ​ ​ 3,925.1 ​ 3,979.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets designated to the Closed Block ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ ​ 2,353.3 ​ 2,269.6 ​ Fixed maturities, trading ​ ​ 2.6 ​ 2.6 ​ Equity securities ​ ​ 1.1 ​ 1.1 ​ Mortgage loans ​ ​ 565.9 ​ 622.8 ​ Policy loans ​ ​ 456.8 ​ 486.0 ​ Other investments ​ ​ 61.7 ​ 46.4 ​ Total investments ​ ​ 3,441.4 ​ 3,428.5 ​ Cash and cash equivalents ​ ​ 23.2 ​ 47.5 ​ Accrued investment income ​ ​ 35.4 ​ 38.1 ​ Premiums due and other receivables ​ ​ 8.3 ​ 9.7 ​ Deferred tax asset ​ ​ 24.2 ​ 29.5 ​ Total assets designated to the Closed Block ​ ​ 3,532.5 ​ 3,553.3 ​ Excess of Closed Block liabilities over assets designated to the Closed Block ​ ​ 392.6 ​ 426.0 ​ Amounts included in accumulated other comprehensive income ​ ​ 0.9 ​ 0.9 ​ Maximum future earnings to be recognized from Closed Block assets and liabilities ​ $ 393.5 ​ $ 426.9 ​ ​
Closed Block Revenues and Expenses (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ 217.6 ​ $ 227.6 ​ $ 244.2 ​ Net investment income ​ ​ 143.6 ​ 154.4 ​ 160.5 ​ Net realized capital gains (losses) ​ ​ 16.0 ​ 7.4 ​ (3.4) ​ Total revenues ​ ​ 377.2 ​ 389.4 ​ 401.3 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ ​ 212.8 ​ 204.4 ​ 211.5 ​ Dividends to policyholders ​ ​ 117.8 ​ 116.3 ​ 120.9 ​ Operating expenses ​ ​ 2.7 ​ 2.9 ​ 3.3 ​ Total expenses ​ ​ 333.3 ​ 323.6 ​ 335.7 ​ Closed Block revenues, net of Closed Block expenses, before income taxes ​ ​ 43.9 ​ 65.8 ​ 65.6 ​ Income taxes ​ ​ 8.4 ​ 12.9 ​ 11.1 ​ Closed Block revenues, net of Closed Block expenses and income taxes ​ ​ 35.5 ​ 52.9 ​ 54.5 ​ Funding adjustments ​ ​ (2.2) ​ (3.0) ​ (0.5) ​ Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustments ​ $ 33.3 ​ $ 49.9 ​ $ 54.0 ​ ​
Change in Maximum Future Earnings of the Closed Block (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Beginning of year ​ $ 426.9 ​ $ 476.8 ​ $ 532.1 ​ Effects of implementation of accounting changes (1) ​ ​ 0.1 ​ ​ — ​ ​ 1.3 ​ End of year ​ ​ 393.5 ​ 426.9 ​ 476.8 ​ Change in maximum future earnings ​ $ (33.3) ​ $ (49.9) ​ $ (54.0) ​ (1) Includes the effects of implementation of accounting changes related to credit losses in 2020 and equity investments and the reclassification of certain tax effects in 2018.

Deferred Acquisition Costs (Tab

Deferred Acquisition Costs (Tables)	12 Months Ended
	Dec. 31, 2020
Deferred Acquisition Costs
Deferred Acquisition Costs Rollforward (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Balance at beginning of year ​ $ 3,521.3 ​ $ 3,693.5 ​ $ 3,540.7 ​ Costs deferred during the year ​ ​ 457.0 ​ 473.5 ​ 414.9 ​ Amortized to expense during the year (1) ​ ​ (388.1) ​ (347.0) ​ (253.5) ​ Adjustment related to unrealized (gains) losses on available-for-sale securities and derivative instruments ​ ​ (180.5) ​ (298.7) ​ 184.9 ​ Other (2) ​ ​ — ​ ​ — ​ ​ (193.5) ​ Balance at end of year ​ $ 3,409.7 ​ $ 3,521.3 ​ $ 3,693.5 ​ (1) Includes adjustments for revisions to EGPs. (2) Reflects the impact of capitalized costs written off or transferred from DAC to a contract cost asset as a result of adopting revenue recognition guidance in 2018. See Note 1, Nature of Operations and Significant Accounting Policies, under the caption “Recent Accounting Pronouncements” for further details .

Insurance Liabilities (Tables)

Insurance Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Contractholder Funds (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Liabilities for investment contracts: ​ ​ ​ ​ ​ ​ ​ Liabilities for individual annuities ​ $ 12,864.1 ​ $ 13,457.5 ​ GICs ​ ​ 11,858.0 ​ 10,423.5 ​ Funding agreements ​ ​ 9,407.3 ​ 8,640.6 ​ Other investment contracts ​ ​ 1,762.4 ​ 1,596.7 ​ Total liabilities for investment contracts ​ ​ 35,891.8 ​ 34,118.3 ​ Universal life and other reserves ​ ​ 7,345.9 ​ 7,249.2 ​ Total contractholder funds ​ $ 43,237.7 ​ $ 41,367.5 ​ ​
Liability for Unpaid Claims (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Balance at beginning of year ​ $ 2,365.5 ​ $ 2,252.7 ​ $ 2,130.5 ​ Less: reinsurance recoverable ​ ​ 403.8 ​ ​ 404.3 ​ ​ 375.8 ​ Net balance at beginning of year ​ ​ 1,961.7 ​ ​ 1,848.4 ​ ​ 1,754.7 ​ Incurred: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current year ​ ​ 1,376.8 ​ 1,361.3 ​ 1,268.8 ​ Prior years ​ ​ 26.6 ​ 0.8 ​ 0.3 ​ Total incurred ​ ​ 1,403.4 ​ 1,362.1 ​ 1,269.1 ​ Payments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current year ​ ​ 863.8 ​ 869.4 ​ 815.7 ​ Prior years ​ ​ 403.3 ​ 379.4 ​ 359.7 ​ Total payments ​ ​ 1,267.1 ​ 1,248.8 ​ 1,175.4 ​ Net balance at end of year ​ ​ 2,098.0 ​ ​ 1,961.7 ​ ​ 1,848.4 ​ Plus: reinsurance recoverable ​ ​ 436.9 ​ ​ 403.8 ​ ​ 404.3 ​ Balance at end of year ​ $ 2,534.9 ​ $ 2,365.5 ​ $ 2,252.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts not included in the rollforward above: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claim adjustment expense liabilities ​ $ 57.8 ​ $ 57.9 ​ $ 54.6 ​ ​
Reconciliation of unpaid claims to liability for unpaid claims (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ Dental, Vision, STD, ​ ​ ​ ​ ​ ​ ​ ​ ​ LTD and Group Life ​ Critical Illness and ​ ​ ​ ​ ​ ​ ​ ​ Waiver Accident Group Life Consolidated ​ ​ (in millions) ​ Net outstanding liabilities for unpaid claims ​ $ 1,208.8 ​ $ 70.4 ​ $ 54.0 ​ $ 1,333.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reconciling items: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reinsurance recoverable on unpaid claims ​ ​ 53.3 ​ ​ — ​ ​ 0.1 ​ ​ 53.4 ​ Impact of discounting ​ ​ (214.5) ​ ​ — ​ ​ — ​ ​ (214.5) ​ Liability for unpaid claims - short-duration contracts ​ $ 1,047.6 ​ $ 70.4 ​ $ 54.1 ​ ​ 1,172.1 ​ Insurance contracts other than short-duration ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 1,362.8 ​ Liability for unpaid claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,534.9 ​ ​
Claim Duration and Payout (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 (1) ​ ​ ​ ​ ​ Dental, Vision, STD, ​ ​ ​ ​ ​ LTD and Group Life ​ Critical Illness and ​ Group ​ Year Waiver Accident Life ​ 1 ​ 7.7 % 91.7 % 81.5 % 2 ​ 24.3 ​ 8.0 ​ 17.3 ​ 3 ​ 15.1 ​ ​ ​ ​ ​ 4 ​ 8.2 ​ ​ ​ ​ ​ 5 ​ 5.7 ​ ​ ​ ​ ​ 6 ​ 5.2 ​ ​ ​ ​ ​ 7 ​ 4.2 ​ ​ ​ ​ ​ 8 ​ 3.6 ​ ​ ​ ​ ​ 9 ​ 3.4 ​ ​ ​ ​ ​ 10 ​ 2.6 ​ ​ ​ ​ ​ (1) Unaudited.
Discounting (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dental, Vision, STD, ​ ​ ​ ​ ​ ​ ​ LTD and Group Life ​ Critical Illness and ​ ​ ​ ​ ​ ​ Waiver ​ Accident ​ Group Life ​ ​ ​ ($ in millions) ​ Carrying amount of liabilities for unpaid claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ $ ​ ​ 1,047.6 ​ $ ​ ​ 70.4 ​ ​ $ ​ ​ 54.1 ​ December 31, 2019 ​ ​ ​ ​ 1,029.9 ​ ​ ​ ​ 71.2 ​ ​ ​ ​ ​ 50.4 ​ Range of discount rates ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ 2.8 - 7.0 % ​ — - — % ​ ​ — - — % December 31, 2019 ​ ​ 3.3 - 7.0 ​ ​ — - — ​ ​ ​ — - — ​ Aggregate amount of discount ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ $ ​ ​ 214.5 ​ $ ​ ​ — ​ ​ $ ​ ​ — ​ December 31, 2019 ​ ​ ​ ​ 215.0 ​ ​ ​ ​ — ​ ​ ​ ​ ​ — ​ Interest accretion ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ $ ​ ​ 33.9 ​ $ ​ ​ — ​ ​ $ ​ ​ — ​ December 31, 2019 ​ ​ ​ ​ 34.2 ​ ​ ​ ​ — ​ ​ ​ ​ ​ — ​ December 31, 2018 ​ ​ ​ ​ 34.5 ​ ​ ​ ​ — ​ ​ ​ ​ ​ — ​
Long-Term Disability/Group Life Waiver
Claims Development (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Incurred ​ ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ but not ​ ​ number of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ reported ​ ​ reported ​ ​ ​ Net incurred claims (1) ​ claims ​ ​ claims ​ ​ ​ December 31, ​ ​ 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2020 2020 ​ ​ ​ ($ in millions) ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2011 ​ $ 203.7 ​ $ 192.6 ​ $ 185.4 ​ $ 184.8 ​ $ 178.4 ​ $ 172.3 ​ $ 169.6 ​ $ 167.6 ​ $ 166.5 ​ $ 167.0 ​ $ 0.1 ​ ​ 6,294 ​ 2012 ​ ​ ​ ​ ​ 217.9 ​ ​ 200.0 ​ ​ 191.1 ​ ​ 189.5 ​ ​ 181.8 ​ ​ 174.8 ​ ​ 173.3 ​ ​ 171.9 ​ ​ 173.1 ​ ​ 0.1 ​ ​ 6,445 ​ 2013 ​ ​ ​ ​ ​ ​ ​ ​ 219.3 ​ ​ 203.3 ​ ​ 188.4 ​ ​ 190.7 ​ ​ 182.3 ​ ​ 179.5 ​ ​ 177.1 ​ ​ 173.4 ​ ​ 0.1 ​ ​ 7,050 ​ 2014 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 242.2 ​ ​ 231.4 ​ ​ 214.4 ​ ​ 218.1 ​ ​ 206.2 ​ ​ 201.9 ​ ​ 202.0 ​ ​ 0.1 ​ ​ 7,603 ​ 2015 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 231.0 ​ ​ 227.2 ​ ​ 217.2 ​ ​ 215.3 ​ ​ 208.2 ​ ​ 210.0 ​ ​ 0.1 ​ ​ 7,179 ​ 2016 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 229.8 ​ ​ 228.4 ​ ​ 219.4 ​ ​ 219.5 ​ ​ 214.4 ​ ​ 0.1 ​ ​ 6,163 ​ 2017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 238.4 ​ ​ 239.7 ​ ​ 243.1 ​ ​ 245.8 ​ ​ 4.4 ​ ​ 6,074 ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 239.4 ​ ​ 245.1 ​ ​ 239.2 ​ ​ 6.6 ​ ​ 5,738 ​ 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 255.2 ​ ​ 248.4 ​ ​ 3.2 ​ ​ 5,858 ​ 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 252.1 ​ ​ 87.0 ​ ​ 3,588 ​ Total net incurred claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,125.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cumulative paid claims (1) ​ ​ December 31, ​ 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 ​ ​ (in millions) Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2011 ​ $ 11.2 ​ $ 50.0 ​ $ 72.5 ​ $ 85.7 ​ $ 95.4 ​ $ 105.2 ​ $ 112.6 ​ $ 119.3 ​ $ 125.4 ​ $ 129.7 2012 ​ ​ ​ ​ ​ 13.8 ​ ​ 55.1 ​ ​ 80.8 ​ ​ 93.7 ​ ​ 104.6 ​ ​ 112.9 ​ ​ 120.0 ​ ​ 126.1 ​ ​ 131.5 2013 ​ ​ ​ ​ ​ ​ ​ ​ 12.5 ​ ​ 55.0 ​ ​ 81.4 ​ ​ 97.0 ​ ​ 106.4 ​ ​ 116.4 ​ ​ 123.2 ​ ​ 129.0 2014 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 16.1 ​ ​ 66.0 ​ ​ 96.3 ​ ​ 111.8 ​ ​ 122.3 ​ ​ 132.4 ​ ​ 140.8 2015 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 16.9 ​ ​ 67.0 ​ ​ 98.0 ​ ​ 114.6 ​ ​ 126.8 ​ ​ 137.1 2016 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 16.2 ​ ​ 70.6 ​ ​ 105.6 ​ ​ 124.9 ​ ​ 136.8 2017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 17.8 ​ ​ 76.5 ​ ​ 115.0 ​ ​ 135.9 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 20.1 ​ ​ 79.9 ​ ​ 115.7 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 19.2 ​ ​ 79.7 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 20.6 Total net paid claims ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 1,156.8 All outstanding liabilities for unpaid claims prior to 2011 net of reinsurance ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 240.2 Total outstanding liabilities for unpaid claims net of reinsurance ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 1,208.8 (1) 2011-2019 unaudited.
Dental/Vision/Short-Term Disability/Critical Illness/Accident
Claims Development (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Incurred ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ but not ​ number of ​ ​ ​ ​ ​ reported ​ reported ​ ​ ​ Net incurred claims (1) ​ claims ​ claims ​ ​ ​ December 31, ​ ​ 2019 2020 2020 2020 ​ ​ ($ in millions) ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 724.7 ​ $ 711.6 ​ $ — ​ ​ 3,363,947 ​ 2020 ​ ​ ​ ​ ​ 679.8 ​ ​ 45.0 ​ ​ 2,899,957 ​ Total net incurred claims ​ ​ ​ ​ $ 1,391.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ paid claims (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2020 ​ ​ ​ ​ ​ ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 653.5 ​ $ 711.5 ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ ​ ​ 609.5 ​ ​ ​ ​ ​ ​ ​ Total net paid claims ​ ​ ​ ​ ​ 1,321.0 ​ ​ ​ ​ ​ ​ ​ All outstanding liabilities for unpaid claims prior to 2019 net of reinsurance ​ ​ ​ ​ ​ — ​ ​ ​ ​ ​ ​ ​ Total outstanding liabilities for unpaid claims net of reinsurance ​ ​ ​ ​ $ 70.4 ​ ​ ​ ​ ​ ​ ​ (1) 2019 unaudited.
Group Life
Claims Development (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Incurred ​ Cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ but not ​ number of ​ ​ ​ ​ ​ reported ​ reported ​ ​ ​ Net incurred claims (1) ​ claims ​ claims ​ ​ ​ December 31, ​ ​ 2019 2020 2020 2020 ​ ​ ($ in millions) ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 228.3 ​ $ 224.6 ​ $ 0.7 ​ ​ 5,117 ​ 2020 ​ ​ ​ ​ ​ 270.6 ​ ​ 21.9 ​ ​ 5,505 ​ Total net incurred claims ​ ​ ​ ​ $ 495.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cumulative ​ ​ ​ ​ ​ ​ ​ ​ ​ paid claims (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ ​ ​ ​ 2019 2020 ​ ​ ​ ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ Incurral year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 181.7 ​ $ 223.0 ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ ​ ​ 219.3 ​ ​ ​ ​ ​ ​ ​ Total net paid claims ​ ​ ​ ​ ​ 442.3 ​ ​ ​ ​ ​ ​ ​ All outstanding liabilities for unpaid claims prior to 2019 net of reinsurance ​ ​ ​ ​ ​ 1.1 ​ ​ ​ ​ ​ ​ ​ Total outstanding liabilities for unpaid claims net of reinsurance ​ ​ ​ ​ $ 54.0 ​ ​ ​ ​ ​ ​ ​ (1) 2019 unaudited.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt
Short-Term Debt (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Financing ​ ​ ​ ​ ​ ​ Short-term debt Obligor/Applicant structure Maturity Capacity outstanding ​ ​ ​ ​ ​ ​ (in millions) PFG, Principal Financial Services, Inc. ("PFS") and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life as co-borrowers Credit facility November 2023 ​ $ 600.0 ​ $ — PFG, PFS, Principal Life and Principal Financial ​ ​ ​ Services V (UK) LTD as co-borrowers Credit facility November 2023 ​ 200.0 ​ — Principal International Chile (1) Unsecured lines of credit ​ 186.6 ​ 84.7 Total ​ $ 986.6 ​ $ 84.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Financing ​ ​ ​ ​ ​ ​ Short-term debt Obligor/Applicant structure Maturity Capacity outstanding ​ ​ ​ ​ ​ ​ (in millions) PFG, PFS and Principal Life as co-borrowers Credit facility November 2023 ​ $ 600.0 ​ $ — PFG, PFS, Principal Life and Principal Financial ​ ​ Services V (UK) LTD as co-borrowers Credit facility November 2023 ​ 200.0 ​ — Principal International Chile (1) Unsecured lines of credit ​ ​ ​ 134.5 ​ 93.4 Principal Life Unsecured line of credit ​ September 2020 ​ 60.0 ​ — Total ​ ​ ​ ​ ​ $ 994.5 ​ $ 93.4 (1) The unsecured lines of credit can be used for repurchase agreements or other borrowings. Each line has a maturity of less than one year .
Long-Term Debt (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Principal Net unamortized Carrying ​ ​ (in millions) 3.3% notes payable, due 2022 ​ $ 300.0 ​ $ (0.7) ​ $ 299.3 ​ 3.125% notes payable, due 2023 ​ ​ 300.0 ​ ​ (0.7) ​ 299.3 ​ 3.4% notes payable, due 2025 ​ ​ 400.0 ​ ​ (2.2) ​ 397.8 ​ 3.1% notes payable, due 2026 ​ ​ 350.0 ​ ​ (2.1) ​ ​ 347.9 ​ 3.7% notes payable, due 2029 ​ ​ 500.0 ​ ​ (5.5) ​ ​ 494.5 ​ 2.125% notes payable, due 2030 ​ ​ 600.0 ​ ​ (4.6) ​ ​ 595.4 ​ 6.05% notes payable, due 2036 ​ ​ 505.6 ​ ​ (2.5) ​ 503.1 ​ 4.625% notes payable, due 2042 ​ ​ 300.0 ​ ​ (3.1) ​ 296.9 ​ 4.35% notes payable, due 2043 ​ ​ 300.0 ​ ​ (3.1) ​ 296.9 ​ 4.3% notes payable, due 2046 ​ ​ 300.0 ​ ​ (3.2) ​ ​ 296.8 ​ Floating rate notes payable, due 2055 ​ ​ 400.0 ​ ​ (4.7) ​ 395.3 ​ Non-recourse mortgages and notes payable ​ 55.5 ​ 0.5 ​ 56.0 ​ Total long-term debt ​ $ 4,311.1 ​ $ (31.9) ​ $ 4,279.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Principal Net unamortized Carrying ​ ​ (in millions) ​ 3.3% notes payable, due 2022 ​ $ 300.0 ​ $ (1.0) ​ $ 299.0 ​ 3.125% notes payable, due 2023 ​ ​ 300.0 ​ ​ (1.0) ​ ​ 299.0 ​ 3.4% notes payable, due 2025 ​ ​ 400.0 ​ ​ (2.6) ​ 397.4 ​ 3.1% notes payable, due 2026 ​ ​ 350.0 ​ ​ (2.5) ​ ​ 347.5 ​ 3.7% notes payable, due 2029 ​ ​ 500.0 ​ ​ (6.1) ​ ​ 493.9 ​ 6.05% notes payable, due 2036 ​ ​ 505.6 ​ ​ (2.4) ​ 503.2 ​ 4.625% notes payable, due 2042 ​ ​ 300.0 ​ ​ (3.2) ​ 296.8 ​ 4.35% notes payable, due 2043 ​ ​ 300.0 ​ ​ (3.3) ​ ​ 296.7 ​ 4.3% notes payable, due 2046 ​ ​ 300.0 ​ ​ (3.3) ​ ​ 296.7 ​ 4.7% notes payable, due 2055 ​ ​ 400.0 ​ ​ (4.9) ​ 395.1 ​ Non-recourse mortgages and notes payable ​ ​ 107.6 ​ ​ 1.2 ​ 108.8 ​ Total long-term debt ​ $ 3,763.2 ​ $ (29.1) ​ $ 3,734.1 ​
Future Annual Maturities of Long-Term Debt (Table)	As of December 31, 2020, future annual maturities of long-term debt were as follows (in millions): ​ ​ ​ ​ ​ ​ Year ending December 31: ​ 2021 ​ $ 2.0 ​ 2022 ​ ​ 301.4 ​ 2023 ​ ​ 323.8 ​ 2024 ​ ​ 17.5 ​ 2025 ​ ​ 398.2 ​ Thereafter ​ ​ 3,236.3 ​ Total future maturities of long-term debt ​ $ 4,279.2 ​ ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Taxes
Income Tax Expense (Benefit) from Continuing Operations (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Current income taxes (benefits): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ $ 15.8 ​ $ 31.9 ​ $ (48.9) ​ State ​ ​ 5.0 ​ 18.1 ​ 10.3 ​ Foreign ​ ​ 55.4 ​ 45.6 ​ 51.7 ​ Tax benefit of operating loss carryforward ​ ​ (3.3) ​ (3.0) ​ (13.5) ​ Total current income taxes (benefits) ​ ​ 72.9 ​ 92.6 ​ (0.4) ​ Deferred income taxes (benefits): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ ​ 143.6 ​ 108.6 ​ 224.3 ​ State ​ ​ 11.5 ​ 6.9 ​ 19.2 ​ Foreign ​ ​ 37.0 ​ 41.1 ​ (12.4) ​ Total deferred income taxes ​ ​ 192.1 ​ 156.6 ​ 231.1 ​ Income taxes ​ $ 265.0 ​ $ 249.2 ​ $ 230.7 ​ ​
Income Before Income Taxes, Domestic and Foreign (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Domestic $ 1,323.2 $ 1,351.9 $ 1,661.1 ​ Foreign ​ ​ 370.3 ​ ​ 341.4 ​ ​ 123.3 ​ Total income before income taxes $ 1,693.5 $ 1,693.3 $ 1,784.4 ​ ​
Reconciliation Between U.S. Corporate Income Tax Rate and Effective Income Tax Rate from Continuing Operations (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 U.S. corporate income tax rate 21 % 21 % 21 % Dividends received deduction ​ (4) ​ (5) ​ (4) ​ Tax credits ​ (3) ​ (3) ​ (3) ​ Impact of equity method presentation ​ (1) ​ (2) ​ (1) ​ Interest exclusion from taxable income ​ (1) ​ — ​ (1) ​ Impact of the Tax Cuts and Jobs Act ​ — ​ — ​ (3) ​ State income taxes ​ 1 ​ 1 ​ 1 ​ Local country permanent tax adjustments ​ — ​ 1 ​ 1 ​ Other ​ 3 ​ 2 ​ 2 ​ Effective income tax rate ​ 16 % 15 % 13 %
Changes in Unrecognized Tax Benefits (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Balance at beginning of period ​ $ 61.6 ​ $ 42.1 ​ $ 194.1 ​ Additions based on tax positions related to the current year ​ ​ 1.3 ​ 0.1 ​ 0.8 ​ Additions for tax positions of prior years ​ ​ 17.4 ​ 23.1 ​ 43.7 ​ Reductions for tax positions related to the current year ​ ​ (3.2) ​ (3.2) ​ (10.6) ​ Reductions for tax positions of prior years ​ ​ — ​ (0.5) ​ (23.2) ​ Settlements ​ ​ (14.5) ​ ​ — ​ ​ (162.7) ​ Expired statute of limitations ​ ​ (15.7) ​ ​ — ​ ​ — ​ Balance at end of period (1) ​ $ 46.9 ​ $ 61.6 ​ $ 42.1 ​ (1) If recognized, $1.1 million of the above amount of unrecognized tax benefits would reduce our 2020 effective income tax rate. We recognize interest and penalties related to uncertain tax positions in operating expenses within the consolidated statements of operations.
Components of Net Deferred Income Taxes (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Deferred income tax assets: ​ ​ ​ ​ ​ ​ ​ Investments, including derivatives ​ $ 588.4 ​ $ 237.0 ​ Insurance liabilities ​ ​ 552.4 ​ 143.2 ​ Net operating and capital loss carryforwards ​ ​ 69.2 ​ 71.1 ​ Tax credit carryforwards ​ ​ 4.6 ​ ​ 106.0 ​ Employee benefits ​ ​ 389.1 ​ 338.9 ​ Foreign currency translation ​ ​ 9.7 ​ ​ 14.0 ​ Other deferred income tax assets ​ ​ 52.5 ​ 45.2 ​ Gross deferred income tax assets ​ ​ 1,665.9 ​ 955.4 ​ Valuation allowance ​ ​ (18.4) ​ (16.7) ​ Total deferred income tax assets ​ ​ 1,647.5 ​ 938.7 ​ Deferred income tax liabilities: ​ ​ ​ ​ ​ ​ ​ Deferred acquisition costs ​ ​ (522.6) ​ (562.9) ​ Investments, including derivatives ​ ​ (990.4) ​ (443.7) ​ Net unrealized gains on available-for-sale securities ​ ​ (1,762.1) ​ (1,039.9) ​ Real estate ​ ​ (158.5) ​ (147.9) ​ Intangible assets ​ ​ (387.5) ​ (342.3) ​ Other deferred income tax liabilities ​ ​ (43.4) ​ (75.0) ​ Total deferred income tax liabilities ​ ​ (3,864.5) ​ (2,611.7) ​ Total net deferred income tax liabilities ​ $ (2,217.0) ​ $ (1,673.0) ​ ​
Net Deferred Income Taxes by Jurisdiction (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Deferred income tax assets: ​ ​ ​ ​ ​ ​ ​ State ​ $ 81.1 ​ $ 94.9 ​ Foreign ​ ​ 32.7 ​ ​ 28.7 ​ Net deferred income tax assets ​ ​ 113.8 ​ 123.6 ​ Deferred income tax liabilities: ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ ​ (2,011.8) ​ (1,507.6) ​ Foreign ​ ​ (319.0) ​ (289.0) ​ Net deferred income tax liabilities ​ ​ (2,330.8) ​ (1,796.6) ​ Total net deferred income tax liabilities ​ $ (2,217.0) ​ $ (1,673.0) ​ ​

Employee and Agent Benefits (Ta

Employee and Agent Benefits (Tables)	12 Months Ended
	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans
Obligations and Funded Status (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement ​ ​ Pension benefits ​ benefits ​ ​ December 31, ​ December 31, ​ 2020 2019 2020 2019 ​ ​ (in millions) Change in benefit obligation ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefit obligation at beginning of year ​ $ (3,692.1) ​ $ (3,239.2) ​ $ (101.4) ​ $ (98.9) ​ Service cost ​ ​ (72.7) ​ (66.0) ​ ​ — ​ — ​ Interest cost ​ ​ (117.3) ​ (126.5) ​ ​ (2.8) ​ (3.7) ​ Actuarial loss ​ ​ (462.4) ​ (506.4) ​ ​ (11.7) ​ (4.8) ​ Participant contributions ​ ​ — ​ — ​ ​ (6.0) ​ (4.4) ​ Benefits paid ​ ​ 134.3 ​ 123.6 ​ ​ 12.8 ​ 12.2 ​ Plan amendments ​ ​ — ​ 122.4 ​ ​ 1.0 ​ ​ (1.8) ​ Other ​ ​ — ​ ​ — ​ ​ 0.1 ​ ​ — ​ Benefit obligation at end of year ​ $ (4,210.2) ​ $ (3,692.1) ​ $ (108.0) ​ $ (101.4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in plan assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at beginning of year ​ $ 2,926.0 ​ $ 2,498.2 ​ $ 732.8 ​ $ 643.9 ​ Actual return on plan assets ​ ​ 521.3 ​ 520.9 ​ ​ 53.1 ​ 95.5 ​ Employer contribution ​ ​ 60.5 ​ 30.5 ​ ​ 1.5 ​ 1.2 ​ Participant contributions ​ ​ — ​ — ​ ​ 6.0 ​ 4.4 ​ Benefits paid ​ ​ (134.3) ​ (123.6) ​ ​ (12.8) ​ (12.2) ​ Fair value of plan assets at end of year ​ $ 3,373.5 ​ $ 2,926.0 ​ $ 780.6 ​ $ 732.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount recognized in statement of financial position ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other assets ​ $ — ​ $ — ​ $ 675.5 ​ $ 635.1 ​ Other liabilities ​ ​ (836.7) ​ (766.1) ​ ​ (2.9) ​ (3.7) ​ Total ​ $ (836.7) ​ $ (766.1) ​ $ 672.6 ​ $ 631.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount recognized in accumulated other comprehensive (income) loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net actuarial (gain) loss ​ $ 760.0 ​ $ 737.5 ​ $ (22.8) ​ $ (17.4) ​ Prior service benefit ​ ​ (121.0) ​ (137.8) ​ ​ (7.3) ​ (7.3) ​ Pre-tax accumulated other comprehensive (income) loss ​ $ 639.0 ​ $ 599.7 ​ $ (30.1) ​ $ (24.7) ​ ​
Components of Net Periodic Benefit Cost (Income) (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension benefits ​ Other postretirement benefits ​ ​ For the year ended December 31, ​ 2020 2019 2018 2020 2019 2018 ​ ​ (in millions) Service cost ​ $ 72.7 ​ $ 66.0 ​ $ 73.0 ​ $ — ​ $ — ​ $ 0.1 ​ Interest cost ​ ​ 117.3 ​ 126.5 ​ 119.5 ​ ​ 2.8 ​ 3.7 ​ 3.5 ​ Expected return on plan assets ​ ​ (156.8) ​ (148.8) ​ (157.0) ​ ​ (36.0) ​ (33.2) ​ (33.6) ​ Amortization of prior service benefit ​ ​ (16.8) ​ (11.3) ​ (3.4) ​ ​ (1.0) ​ (1.2) ​ (13.9) ​ Recognized net actuarial (gain) loss ​ ​ 75.4 ​ 70.1 ​ 67.8 ​ ​ — ​ 0.1 ​ (1.5) ​ Net periodic benefit cost (income) ​ $ 91.8 ​ $ 102.5 ​ $ 99.9 ​ $ (34.2) ​ $ (30.6) ​ $ (45.4) ​ ​
Amounts Recognized in Net Periodic Benefit Cost and Accumulated Other Comprehensive (Income) Loss (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension ​ Other postretirement ​ ​ benefits ​ benefits ​ ​ For the year ended December 31, ​ 2020 2019 2020 2019 ​ ​ (in millions) Other changes recognized in accumulated other comprehensive (income) loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net actuarial (gain) loss ​ $ 97.9 ​ $ 134.3 ​ $ (5.4) ​ $ (57.5) ​ Prior service (benefit) cost ​ ​ — ​ ​ (122.4) ​ ​ (1.0) ​ ​ 1.7 ​ Amortization of net loss ​ ​ (75.4) ​ (70.1) ​ ​ — ​ (0.1) ​ Amortization of prior service benefit ​ ​ 16.8 ​ 11.3 ​ ​ 1.0 ​ 1.2 ​ Total recognized in pre-tax accumulated other comprehensive (income) loss ​ $ 39.3 ​ $ (46.9) ​ $ (5.4) ​ $ (54.7) ​ Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss ​ $ 131.1 ​ $ 55.6 ​ $ (39.6) ​ $ (85.3) ​ ​
Weighted-Average Assumptions Used to Determine Benefit Obligations (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ Pension benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 ​ Discount rate ​ 2.50 % 3.25 % Interest crediting rate - cash balance benefit ​ 5.00 % — % Rate of compensation increase: ​ ​ ​ ​ ​ Cash balance benefit ​ 4.92 % 4.95 % Traditional benefit ​ 2.96 % 2.98 % ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 ​ Discount rate ​ 2.10 % 2.95 % Rate of compensation increase ​ N/A ​ N/A ​ ​
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ Discount rate (1) ​ 3.25 % 3.70 % 3.60 % Expected long-term return on plan assets ​ 5.60 % 5.95 % 6.30 % Interest crediting rate - cash balance benefit ​ 5.00 % — % — % Rate of compensation increase: ​ ​ ​ ​ ​ ​ ​ Cash balance benefit ​ 4.95 % 4.94 % 4.96 % Traditional benefit ​ 2.98 % 2.73 % 2.77 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement benefits ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ Discount rate (2) ​ 2.95 % 3.95 % 3.35 % Expected long-term return on plan assets ​ 4.94 % 5.19 % 4.85 % Rate of compensation increase ​ N/A ​ N/A ​ 2.39 % (1) During the second quarter of 2019, we amended The Principal Pension Plan and The Principal Financial Group Nonqualified Defined Benefit Plan for Employees to end traditional benefit accruals as of December 31, 2022, and begin cash balance accruals January 1, 2023. We remeasured the associated plan assets and pension benefit obligations as of May 31, 2019. A discount rate of 4.15% was used until the remeasurement date at which time a discount rate of 3.70% was used. See "Pension Plan Changes and Plan Gains/Losses" for further details. (2) During the second quarter 2020, subsidy increases provided under the long-term care plan were capped at 5% per calendar year. This change was remeasured as of March 31, 2020. A discount rate of 2.95% was used until the remeasurement date at which time a discount rate of 2.90% was used.
Assumed Health Care Cost Trend Rates (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ Health care cost trend rate assumed for next year under age 65 ​ 6.75 % 6.75 % Health care cost trend rate assumed for next year age 65 and over ​ 6.00 % 6.00 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) ​ 4.50 % 4.50 % Year that the rate reaches the ultimate trend rate (under age 65) ​ 2029 ​ 2028 ​ Year that the rate reaches the ultimate trend rate (65 and older) ​ 2026 ​ 2025 ​ ​
Estimated Future Benefit Payments (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other postretirement ​ ​ ​ ​ ​ ​ benefits (gross benefit ​ ​ ​ ​ ​ ​ payments, including ​ ​ Pension benefits prescription drug benefits) ​ ​ (in millions) ​ Year ending December 31: ​ ​ ​ ​ ​ ​ ​ 2021 ​ $ 160.2 ​ $ 15.5 ​ 2022 ​ ​ 159.9 ​ ​ 14.8 ​ 2023 ​ ​ 166.6 ​ ​ 13.5 ​ 2024 ​ ​ 175.8 ​ ​ 12.2 ​ 2025 ​ ​ 179.3 ​ ​ 10.9 ​ 2026-2030 ​ ​ 1,026.0 ​ ​ 38.3 ​ ​
Defined Benefit Pension Plans Supplemental Information (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ ​ Qualified ​ Nonqualified ​ ​ ​ ​ Qualified ​ Nonqualified ​ ​ ​ ​ Plan Plan Total Plan Plan Total ​ ​ (in millions) Amount recognized in statement of financial position ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other assets ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ Other liabilities ​ ​ (294.9) ​ ​ (541.8) ​ ​ (836.7) ​ (258.7) ​ ​ (507.4) ​ ​ (766.1) ​ Total ​ $ (294.9) ​ $ (541.8) ​ $ (836.7) ​ $ (258.7) ​ $ (507.4) ​ $ (766.1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount recognized in accumulated other comprehensive loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net actuarial loss ​ $ 563.5 ​ $ 196.5 ​ $ 760.0 ​ $ 567.6 ​ $ 169.9 ​ $ 737.5 ​ Prior service benefit ​ ​ (97.8) ​ ​ (23.2) ​ ​ (121.0) ​ (110.3) ​ ​ (27.5) ​ ​ (137.8) ​ Pre-tax accumulated other comprehensive loss ​ $ 465.7 ​ $ 173.3 ​ $ 639.0 ​ $ 457.3 ​ $ 142.4 ​ $ 599.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Components of net periodic benefit cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service cost ​ $ 66.1 ​ $ 6.6 ​ $ 72.7 ​ $ 59.7 ​ $ 6.3 ​ $ 66.0 ​ Interest cost ​ ​ 101.2 ​ ​ 16.1 ​ ​ 117.3 ​ 108.0 ​ ​ 18.5 ​ ​ 126.5 ​ Expected return on plan assets ​ ​ (156.8) ​ ​ — ​ ​ (156.8) ​ (148.8) ​ ​ — ​ ​ (148.8) ​ Amortization of prior service benefit ​ ​ (12.6) ​ ​ (4.2) ​ ​ (16.8) ​ (7.8) ​ ​ (3.5) ​ ​ (11.3) ​ Recognized net actuarial loss ​ ​ 59.9 ​ ​ 15.5 ​ ​ 75.4 ​ 57.6 ​ ​ 12.5 ​ ​ 70.1 ​ Net periodic benefit cost ​ $ 57.8 ​ $ 34.0 ​ $ 91.8 ​ $ 68.7 ​ $ 33.8 ​ $ 102.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other changes recognized in accumulated other comprehensive (income) loss ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net actuarial loss ​ $ 55.7 ​ $ 42.2 ​ $ 97.9 ​ $ 80.8 ​ $ 53.5 ​ $ 134.3 ​ Prior service benefit ​ ​ — ​ ​ — ​ ​ — ​ ​ (107.2) ​ ​ (15.2) ​ ​ (122.4) ​ Amortization of net loss ​ ​ (59.8) ​ ​ (15.6) ​ ​ (75.4) ​ (57.6) ​ ​ (12.5) ​ ​ (70.1) ​ Amortization of prior service benefit ​ ​ 12.6 ​ ​ 4.2 ​ ​ 16.8 ​ 7.8 ​ ​ 3.5 ​ ​ 11.3 ​ Total recognized in pre-tax accumulated other comprehensive (income) loss ​ $ 8.5 ​ $ 30.8 ​ $ 39.3 ​ $ (76.2) ​ $ 29.3 ​ $ (46.9) ​ Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss ​ $ 66.3 ​ $ 64.8 ​ $ 131.1 ​ $ (7.5) ​ $ 63.1 ​ $ 55.6 ​ ​
Pension benefits
Defined Benefit Plans and Other Postretirement Benefit Plans
Accumulated Benefit Obligation in Excess of Plan Assets (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Projected benefit obligation ​ $ 4,210.2 ​ $ 3,692.1 ​ Accumulated benefit obligation ​ ​ 4,136.5 ​ 3,599.5 ​ Fair value of plan assets ​ ​ 3,373.5 ​ 2,926.0 ​ ​
Fair Value of Plan Assets (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Assets ​ Amount ​ Fair value hierarchy level ​ ​ ​ measured at ​ measured at ​ ​ ​ ​ fair value net asset value Level 1 Level 2 Level 3 ​ ​ ​ (in millions) ​ Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pooled separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large cap equity portfolios (1) ​ $ 712.2 ​ $ — ​ $ — ​ $ 712.2 ​ $ — ​ U.S. small/mid cap equity portfolios (2) ​ 121.6 ​ ​ — ​ — ​ 121.6 ​ — ​ Balanced asset portfolios (3) ​ 103.7 ​ ​ — ​ — ​ 103.7 ​ — ​ International equity portfolios (4) ​ 459.6 ​ ​ — ​ — ​ 459.6 ​ — ​ Real estate investment portfolios (5) ​ 195.1 ​ ​ ​ ​ ​ ​ 195.1 ​ ​ ​ Single client separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ ​ 297.5 ​ ​ — ​ ​ 297.5 ​ ​ — ​ ​ — ​ States and political subdivisions ​ ​ 28.0 ​ ​ — ​ ​ — ​ ​ 28.0 ​ ​ — ​ Corporate ​ ​ 1,223.1 ​ ​ — ​ ​ — ​ ​ 1,223.1 ​ ​ — ​ Commercial mortgage-backed securities ​ ​ 13.6 ​ ​ — ​ ​ — ​ ​ 13.6 ​ ​ — ​ Other debt obligations ​ ​ 6.4 ​ ​ — ​ ​ — ​ ​ 6.4 ​ ​ — ​ Hedge funds (6) ​ ​ 155.8 ​ ​ 155.8 ​ ​ — ​ ​ — ​ ​ — ​ Pooled separate account investment (7) ​ ​ 55.1 ​ ​ — ​ ​ — ​ ​ 55.1 ​ ​ — ​ Other (8) ​ ​ 1.8 ​ ​ — ​ ​ — ​ ​ 1.8 ​ ​ — ​ Total ​ $ 3,373.5 ​ $ 155.8 ​ $ 297.5 ​ $ 2,920.2 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Assets ​ Amount ​ Fair value hierarchy level ​ ​ measured at ​ measured at ​ ​ ​ fair value net asset value Level 1 Level 2 Level 3 ​ ​ (in millions) Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pooled separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large cap equity portfolios (1) ​ $ 509.7 ​ $ — ​ $ — ​ $ 509.7 ​ $ — ​ U.S. small/mid cap equity portfolios (2) ​ 90.9 ​ ​ — ​ — ​ 90.9 ​ — ​ Balanced asset portfolios (3) ​ 78.5 ​ ​ — ​ — ​ 78.5 ​ — ​ International equity portfolios (4) ​ 328.6 ​ ​ — ​ — ​ 328.6 ​ — ​ Real estate investment portfolios (5) ​ 193.5 ​ ​ — ​ — ​ 193.5 ​ — ​ Single client separate account investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ ​ 485.9 ​ ​ — ​ ​ 485.9 ​ ​ — ​ ​ — ​ States and political subdivisions ​ ​ 26.1 ​ ​ — ​ ​ — ​ ​ 26.1 ​ ​ — ​ Corporate ​ ​ 1,009.1 ​ ​ — ​ ​ — ​ ​ 1,009.1 ​ ​ — ​ Commercial mortgage-backed securities ​ ​ 32.7 ​ ​ — ​ ​ — ​ ​ 32.7 ​ ​ — ​ Other debt obligations ​ ​ 7.1 ​ ​ — ​ ​ — ​ ​ 7.1 ​ ​ — ​ Hedge funds (6) ​ ​ 129.0 ​ ​ 129.0 ​ ​ — ​ ​ — ​ ​ — ​ Pooled separate account investment (7) ​ ​ 31.5 ​ ​ — ​ ​ — ​ ​ 31.5 ​ ​ — ​ Other (8) ​ ​ 3.4 ​ ​ — ​ ​ — ​ ​ 3.4 ​ ​ — ​ Total ​ $ 2,926.0 ​ $ 129.0 ​ $ 485.9 ​ $ 2,311.1 ​ $ — ​ (1) The portfolios invest primarily in publicly traded equity securities of large U.S. companies. (2) The portfolios invest primarily in publicly traded equity securities of mid-sized and small U.S. companies. (3) The portfolios are a combination of underlying fixed income and equity investment options. These investment options may include balanced, asset allocation, target-date and target-risk investment options. Although typically lower risk than investment options that invest solely in equities, all investment options in this category have the potential to lose value. (4) The portfolios invest primarily in publicly traded equity securities of non-U.S. companies. (5) The portfolio invests primarily in U.S. commercial real estate properties through a separate account. (6) The hedge funds have varying investment strategies that also have a variety of redemption terms and conditions. We do not have unfunded commitments associated with these hedge funds. (7) The single client separate accounts invest in a money market pooled separate account. (8) Includes cash and net (payables)/receivables for the single client separate accounts.
Target Asset Allocation (Table)	​ ​ ​ ​ ​ ​ ​ ​ Asset category Target allocation ​ Fixed income security portfolios ​ 25 % - 80 % Equity portfolios ​ 5 % - 60 % Real estate investment portfolios ​ ​ ​ ​ 10 % Alternatives ​ ​ ​ ​ 5 % ​
Other postretirement benefits
Defined Benefit Plans and Other Postretirement Benefit Plans
Accumulated Benefit Obligation in Excess of Plan Assets (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 ​ ​ (in millions) Accumulated postretirement benefit obligation ​ $ 2.9 ​ $ 3.8 ​ Fair value of plan assets ​ ​ — ​ — ​ ​
Fair Value of Plan Assets (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Assets ​ Fair value hierarchy level ​ ​ ​ measured at ​ ​ ​ ​ fair value Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 0.5 ​ $ 0.5 ​ $ — ​ $ — ​ Fixed income security portfolios: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income investment funds (1) ​ 625.2 ​ 605.9 ​ 19.3 ​ — ​ U.S. equity portfolios (2) ​ 103.5 ​ 38.2 ​ 65.3 ​ — ​ International equity portfolios (3) ​ 51.4 ​ 18.4 ​ 33.0 ​ — ​ Total ​ $ 780.6 ​ $ 663.0 ​ $ 117.6 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Assets ​ Fair value hierarchy level ​ ​ ​ measured at ​ ​ ​ ​ fair value Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Asset category ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 0.6 ​ $ 0.6 ​ $ — ​ $ — ​ Fixed income security portfolios: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income investment funds (1) ​ 370.5 ​ 331.0 ​ 39.5 ​ — ​ U.S. equity portfolios (2) ​ 254.5 ​ 210.3 ​ 44.2 ​ — ​ International equity portfolios (3) ​ ​ 107.2 ​ 88.9 ​ 18.3 ​ — ​ Total ​ $ 732.8 ​ $ 630.8 ​ $ 102.0 ​ $ — ​ (1) The portfolios invest in various fixed income securities, primarily of U.S. origin. These include, but are not limited to, corporate bonds, residential mortgage-backed securities, commercial mortgage-backed securities, U.S. Treasury securities, agency securities, asset-backed securities and collateralized mortgage obligations. (2) The portfolios invest primarily in publicly traded equity securities of large U.S. companies. (3) The portfolios invest primarily in publicly traded equity securities of non-U.S. companies.
Target Asset Allocation (Table)	​ ​ ​ ​ ​ Asset category Target allocation ​ U.S. equity portfolios ​ 35 % International equity portfolios ​ 15 % Fixed income security portfolios ​ 50 %

Contingencies, Guarantees, In_2

Contingencies, Guarantees, Indemnifications and Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Contingencies, Guarantees, Indemnifications and Leases
Lease Assets and Liabilities (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 ​ 2019 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ Operating lease assets (1) ​ $ 234.9 ​ $ 190.0 ​ Finance lease assets (1) ​ 49.5 ​ ​ 31.4 ​ Total lease assets ​ $ 284.4 ​ $ 221.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ Operating lease liabilities (2) ​ $ 231.4 ​ $ 197.5 ​ Finance lease liabilities (2) ​ 50.1 ​ ​ 31.8 ​ Total lease liabilities ​ $ 281.5 ​ $ 229.3 ​ (1) Operating and finance lease assets are primarily reported within property and equipment on the consolidated statements of financial position. (2) Operating and finance lease liabilities are reported within other liabilities on the consolidated statements of financial position.
Lease Cost (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ ​ (in millions) Finance lease cost (1): ​ ​ ​ ​ Amortization of right-of-use assets ​ $ 20.5 ​ $ 14.6 Interest on lease liabilities ​ 1.0 ​ ​ 1.0 Operating lease cost (1) ​ 58.7 ​ ​ 55.8 Other lease cost (1) (2) ​ 8.6 ​ ​ 8.0 Sublease income (3) ​ (1.6) ​ ​ (1.7) Total lease cost ​ $ 87.2 ​ $ 77.7 (1) Finance, operating and other lease costs are primarily included in operating expenses on the consolidated statements of operations. (2) Other lease cost primarily reflects variable and short-term lease costs. (3) Sublease income is included in fees and other revenues on the consolidated statements of operations.
Future Payments Due by Period for Lease Obligations (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases Finance leases Total ​ ​ (in millions) ​ For the twelve months ending December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ $ 56.9 ​ $ 21.5 ​ $ 78.4 ​ 2022 ​ ​ 49.8 ​ ​ 13.6 ​ ​ 63.4 ​ 2023 ​ ​ 39.1 ​ ​ 11.4 ​ ​ 50.5 ​ 2024 ​ ​ 30.5 ​ ​ 3.6 ​ ​ 34.1 ​ 2025 ​ ​ 22.8 ​ ​ 1.2 ​ ​ 24.0 ​ 2026 and thereafter ​ ​ 60.8 ​ ​ — ​ ​ 60.8 ​ Total lease payments ​ ​ 259.9 ​ ​ 51.3 ​ ​ 311.2 ​ Less: interest ​ ​ 28.5 ​ ​ 1.2 ​ ​ 29.7 ​ Present value of lease liabilities ​ $ 231.4 ​ $ 50.1 ​ $ 281.5 ​
Weighted-Average Remaining Lease Term and Weighted-Average Discount Rates (Table)	​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 ​ 2019 ​ Weighted-average remaining lease term (in years): ​ ​ ​ Operating leases 6.7 ​ 6.7 ​ Finance leases 3.0 ​ 2.6 ​ ​ ​ ​ ​ ​ ​ Weighted-average discount rate: ​ ​ Operating leases 3.2 % 3.9 % Finance leases 1.8 % 2.7 %

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Stockholders' Equity
Common Stock Dividends (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 Dividends declared per common share ​ $ 2.24 ​ $ 2.18 ​ $ 2.10 ​
Reconciliation of Outstanding Common Shares (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Beginning balance ​ 276.6 ​ 279.5 ​ 289.0 ​ Shares issued ​ 2.6 ​ 2.6 ​ 2.6 ​ Treasury stock acquired ​ (5.9) ​ (5.5) ​ (12.1) ​ Ending balance ​ 273.3 ​ 276.6 ​ 279.5 ​
Other Comprehensive Income (Loss) (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ Pre-Tax Tax After-Tax ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized gains on available-for-sale securities during the period ​ $ 3,441.4 ​ $ (728.7) ​ $ 2,712.7 ​ Reclassification adjustment for gains included in net income (1) ​ (52.9) ​ 12.6 ​ (40.3) ​ Adjustments for assumed changes in amortization patterns ​ (179.0) ​ 37.6 ​ (141.4) ​ Adjustments for assumed changes in policyholder liabilities ​ (1,478.2) ​ 323.7 ​ (1,154.5) ​ Net unrealized gains on available-for-sale securities ​ 1,731.3 ​ (354.8) ​ 1,376.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized losses on derivative instruments during the period ​ (28.1) ​ ​ 6.5 ​ ​ (21.6) ​ Reclassification adjustment for gains included in net income (3) ​ (27.1) ​ ​ 5.1 ​ ​ (22.0) ​ Adjustments for assumed changes in amortization patterns ​ 2.7 ​ ​ (0.5) ​ ​ 2.2 ​ Adjustments for assumed changes in policyholder liabilities ​ 7.8 ​ ​ (1.6) ​ ​ 6.2 ​ Net unrealized losses on derivative instruments ​ (44.7) ​ ​ 9.5 ​ ​ (35.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign currency translation adjustment during the period ​ ​ (11.7) ​ ​ (2.6) ​ ​ (14.3) ​ Reclassification adjustment for losses included in net income (4) ​ ​ 43.0 ​ ​ 1.9 ​ ​ 44.9 ​ Foreign currency translation adjustment ​ 31.3 ​ ​ (0.7) ​ ​ 30.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized postretirement benefit obligation during the period ​ (91.9) ​ ​ 24.9 ​ ​ (67.0) ​ Amortization of amounts included in net periodic benefit cost (5) ​ 57.6 ​ ​ (15.5) ​ ​ 42.1 ​ Net unrecognized postretirement benefit obligation ​ (34.3) ​ ​ 9.4 ​ ​ (24.9) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income ​ $ 1,683.6 ​ $ (336.6) ​ $ 1,347.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ Pre-Tax Tax After-Tax ​ ​ (in millions) ​ Net unrealized gains on available-for-sale securities during the period ​ $ 4,414.1 ​ $ (947.0) ​ $ 3,467.1 ​ Reclassification adjustment for losses included in net income (1) ​ 47.4 ​ (9.7) ​ 37.7 ​ Adjustments for assumed changes in amortization patterns ​ (293.0) ​ 61.5 ​ (231.5) ​ Adjustments for assumed changes in policyholder liabilities ​ (847.7) ​ 190.5 ​ (657.2) ​ Net unrealized gains on available-for-sale securities ​ 3,320.8 ​ (704.7) ​ 2,616.1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Noncredit component of impairment losses on fixed maturities, available-for-sale during the period ​ 5.2 ​ ​ (1.1) ​ ​ 4.1 ​ Adjustments for assumed changes in amortization patterns ​ (1.4) ​ ​ 0.3 ​ ​ (1.1) ​ Noncredit component of impairment losses on fixed maturities, available-for-sale (2) ​ 3.8 ​ ​ (0.8) ​ ​ 3.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized losses on derivative instruments during the period ​ (0.5) ​ ​ — ​ ​ (0.5) ​ Reclassification adjustment for gains included in net income (3) ​ (23.9) ​ ​ 4.9 ​ ​ (19.0) ​ Adjustments for assumed changes in amortization patterns ​ 3.1 ​ ​ (0.6) ​ ​ 2.5 ​ Adjustments for assumed changes in policyholder liabilities ​ 7.9 ​ ​ (1.9) ​ ​ 6.0 ​ Net unrealized losses on derivative instruments ​ (13.4) ​ ​ 2.4 ​ ​ (11.0) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign currency translation adjustment during the period ​ ​ (112.3) ​ ​ 7.5 ​ ​ (104.8) ​ Reclassification adjustment for losses included in net income (4) ​ ​ 26.1 ​ ​ — ​ ​ 26.1 ​ Foreign currency translation adjustment ​ (86.2) ​ ​ 7.5 ​ ​ (78.7) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized postretirement benefit obligation during the period ​ 43.6 ​ ​ (8.6) ​ ​ 35.0 ​ Amortization of amounts included in net periodic benefit cost (5) ​ 57.7 ​ ​ (15.4) ​ ​ 42.3 ​ Net unrecognized postretirement benefit obligation ​ 101.3 ​ ​ (24.0) ​ ​ 77.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income ​ $ 3,326.3 ​ $ (719.6) ​ $ 2,606.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ Pre-Tax Tax After-Tax ​ ​ (in millions) ​ Net unrealized losses on available-for-sale securities during the period ​ $ (2,517.5) ​ $ 515.4 ​ $ (2,002.1) ​ Reclassification adjustment for losses included in net income (1) ​ 56.4 ​ (5.3) ​ 51.1 ​ Adjustments for assumed changes in amortization patterns ​ 185.9 ​ (39.1) ​ 146.8 ​ Adjustments for assumed changes in policyholder liabilities ​ 346.9 ​ (72.3) ​ 274.6 ​ Net unrealized losses on available-for-sale securities ​ (1,928.3) ​ 398.7 ​ (1,529.6) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Noncredit component of impairment losses on fixed maturities, available-for-sale during the period ​ 39.7 ​ ​ (8.4) ​ ​ 31.3 ​ Adjustments for assumed changes in amortization patterns ​ (5.3) ​ ​ 1.1 ​ ​ (4.2) ​ Adjustments for assumed changes in policyholder liabilities ​ ​ (0.8) ​ ​ 0.1 ​ ​ (0.7) ​ Noncredit component of impairment losses on fixed maturities, available-for-sale (2) ​ 33.6 ​ ​ (7.2) ​ ​ 26.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized gains on derivative instruments during the period ​ 50.4 ​ ​ (3.4) ​ ​ 47.0 ​ Reclassification adjustment for gains included in net income (3) ​ (40.1) ​ ​ 4.2 ​ ​ (35.9) ​ Adjustments for assumed changes in amortization patterns ​ 0.3 ​ ​ (0.1) ​ ​ 0.2 ​ Adjustments for assumed changes in policyholder liabilities ​ 5.7 ​ ​ (1.0) ​ ​ 4.7 ​ Net unrealized gains on derivative instruments ​ 16.3 ​ ​ (0.3) ​ ​ 16.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign currency translation adjustment ​ (303.9) ​ ​ 16.3 ​ ​ (287.6) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized postretirement benefit obligation during the period ​ (125.3) ​ ​ 29.4 ​ ​ (95.9) ​ Amortization of amounts included in net periodic benefit cost (5) ​ 49.0 ​ ​ (14.0) ​ ​ 35.0 ​ Net unrecognized postretirement benefit obligation ​ (76.3) ​ ​ 15.4 ​ ​ (60.9) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss ​ $ (2,258.6) ​ $ 422.9 ​ $ (1,835.7) ​ (1) Pre-tax reclassification adjustments relating to available-for-sale securities are reported in net realized capital gains (losses) on the consolidated statements of operations. (2) Prior to 2020, represents the net impact of (1) unrealized gains resulting from reclassification of previously recognized noncredit impairment losses from OCI to net realized capital gains (losses) for fixed maturities with bifurcated OTTI that had additional credit losses or fixed maturities that previously had bifurcated OTTI that have now been sold or are intended to be sold and (2) unrealized losses resulting from reclassification of noncredit impairment losses for fixed maturities with bifurcated OTTI from net realized capital gains (losses) to OCI. (3) See Note 5, Derivative Financial Instruments, under the caption “Effect of Fair Value and Cash Flow Hedges on Consolidated Statements of Operations” for further details. (4) The 2020 pre-tax reclassification adjustment primarily related to the release of the cumulative translation adjustment from the dissolution of a foreign subsidiary and the net impact of deconsolidated sponsored investment funds and associated net investment hedges. The 2019 pre-tax reclassification adjustment primarily related to deconsolidated sponsored investment funds. The adjustments were reported in net realized capital gains (losses) on the consolidated statements of operations. For the years ended December 31, 2020 and 2019, $8.7 million and $5.7 million, respectively, of this reclassification relates to noncontrolling interest and is reported in net income attributable to noncontrolling interest on the consolidated statements of operations. (5) Amount is comprised of amortization of prior service cost (benefit) and recognized net actuarial (gain) loss, which is reported in operating expenses on the consolidated statements of operations. See Note 11, Employee and Agent Benefits, under the caption “Components of Net Periodic Benefit Cost” for further details.
Accumulated Other Comprehensive Income (Loss) (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Noncredit ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net unrealized ​ component of ​ Net unrealized ​ Foreign ​ Unrecognized ​ Accumulated ​ ​ gains on ​ impairment losses ​ gains ​ currency ​ postretirement ​ other ​ ​ available-for-sale ​ on fixed maturities ​ on derivative ​ translation ​ benefit ​ comprehensive ​ securities (1) available-for-sale (2) instruments adjustment obligation income (loss) ​ ​ (in millions) Balances as of January 1, 2018 ​ $ 1,470.7 ​ $ (58.3) ​ $ 42.7 ​ $ (918.5) ​ $ (371.1) ​ $ 165.5 Other comprehensive loss during the period, net of adjustments ​ (1,580.6) ​ — ​ 51.9 ​ (283.2) ​ (95.9) ​ (1,907.8) Amounts reclassified from AOCI ​ 51.1 ​ 26.4 ​ (35.9) ​ — ​ 35.0 ​ 76.6 Other comprehensive loss ​ (1,529.5) ​ ​ 26.4 ​ ​ 16.0 ​ ​ (283.2) ​ ​ (60.9) ​ ​ (1,831.2) Purchase of subsidiary shares from noncontrolling interest ​ ​ — ​ ​ — ​ ​ — ​ ​ (1.6) ​ ​ — ​ ​ (1.6) Effects of implementation of accounting change related to equity investments, net ​ ​ (1.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (1.0) Effects of implementation of accounting change accounting change related to revenue recognition, net ​ ​ — ​ ​ — ​ ​ — ​ ​ 25.6 ​ ​ — ​ ​ 25.6 Effects of implementation of accounting change related to the reclassification of certain tax effects, net ​ ​ 249.8 ​ ​ (15.2) ​ ​ 5.7 ​ ​ (81.8) ​ ​ (80.9) ​ ​ 77.6 Balances as of December 31, 2018 ​ ​ 190.0 ​ ​ (47.1) ​ ​ 64.4 ​ ​ (1,259.5) ​ ​ (512.9) ​ ​ (1,565.1) Other comprehensive income during the period, net of adjustments ​ ​ 2,578.3 ​ ​ — ​ ​ 8.0 ​ ​ (102.7) ​ ​ 35.0 ​ ​ 2,518.6 Amounts reclassified from AOCI ​ ​ 37.7 ​ ​ 3.0 ​ ​ (19.0) ​ ​ 20.4 ​ ​ 42.3 ​ ​ 84.4 Other comprehensive income ​ ​ 2,616.0 ​ ​ 3.0 ​ ​ (11.0) ​ ​ (82.3) ​ ​ 77.3 ​ ​ 2,603.0 Balances as of December 31, 2019 ​ ​ 2,806.0 ​ ​ (44.1) ​ ​ 53.4 ​ ​ (1,341.8) ​ ​ (435.6) ​ ​ 1,037.9 Other comprehensive income during the period, net of adjustments ​ ​ 1,416.7 ​ ​ — ​ ​ (13.2) ​ ​ (7.3) ​ ​ (67.0) ​ ​ 1,329.2 Amounts reclassified from AOCI ​ ​ (40.3) ​ ​ — ​ ​ (22.0) ​ ​ 36.2 ​ ​ 42.1 ​ ​ 16.0 Other comprehensive income ​ ​ 1,376.4 ​ ​ — ​ ​ (35.2) ​ ​ 28.9 ​ ​ (24.9) ​ ​ 1,345.2 Effects of implementation of accounting change related to credit losses, net ​ ​ (44.1) ​ ​ 44.1 ​ ​ — ​ ​ — ​ ​ — ​ ​ — Balances as of December 31, 2020 ​ $ 4,138.3 ​ $ — ​ $ 18.2 ​ $ (1,312.9) ​ $ (460.5) ​ $ 2,383.1 (1) Net unrealized losses on available-for-sale debt securities for which an allowance for credit loss has been recorded were $2.9 million as of December 31, 2020. (2) Prior to the implementation of authoritative guidance in 2020, the noncredit component of impairment losses on fixed maturities, available-for-sale was included as a separate component of stockholders' equity.
Redeemable Noncontrolling Interest (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Beginning balance ​ $ 264.9 ​ $ 391.2 ​ $ 101.3 ​ Net income (loss) attributable to redeemable noncontrolling interest ​ ​ 7.5 ​ ​ 33.6 ​ ​ (2.1) ​ Redeemable noncontrolling interest of deconsolidated entities (1) ​ ​ (91.9) ​ ​ (505.4) ​ ​ (10.6) ​ Contributions from redeemable noncontrolling interest ​ 136.2 ​ 402.1 ​ 355.0 ​ Distributions to redeemable noncontrolling interest ​ (62.0) ​ (66.3) ​ (36.8) ​ Purchase of subsidiary shares from redeemable noncontrolling interest ​ — ​ (1.1) ​ (7.1) ​ Change in redemption value of redeemable noncontrolling interest ​ 0.2 ​ 5.4 ​ (7.0) ​ Stock-based compensation attributable to redeemable noncontrolling interest ​ ​ 0.1 ​ ​ 0.1 ​ ​ 0.1 ​ Other comprehensive income (loss) attributable to redeemable noncontrolling interest ​ 0.6 ​ 5.3 ​ (1.6) ​ Ending balance ​ $ 255.6 ​ $ 264.9 ​ $ 391.2 ​ (1) We deconsolidated certain sponsored investment funds as they no longer met the requirements for consolidation.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Measurements
Fair Value (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Assets/ ​ Amount ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (liabilities) ​ measured at ​ Fair value hierarchy level ​ ​ ​ measured at ​ net asset ​ ​ ​ ​ fair value value (4) Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 2,111.5 ​ $ — ​ $ 1,768.3 ​ $ 343.2 ​ $ — ​ Non-U.S. governments ​ 1,073.7 ​ ​ — ​ 1.1 ​ 1,072.6 ​ — ​ States and political subdivisions ​ 9,167.8 ​ ​ — ​ — ​ 9,167.8 ​ — ​ Corporate ​ 47,354.8 ​ ​ — ​ — ​ 47,064.0 ​ 290.8 ​ Residential mortgage-backed pass-through securities ​ 2,986.8 ​ ​ — ​ — ​ 2,986.8 ​ — ​ Commercial mortgage-backed securities ​ 4,942.3 ​ ​ — ​ — ​ 4,929.1 ​ 13.2 ​ Collateralized debt obligations (1) ​ 4,027.5 ​ ​ — ​ — ​ 4,000.3 ​ 27.2 ​ Other debt obligations ​ 7,045.9 ​ ​ — ​ — ​ 7,016.7 ​ 29.2 ​ Total fixed maturities, available-for-sale ​ 78,710.3 ​ ​ — ​ 1,769.4 ​ 76,580.5 ​ 360.4 ​ Fixed maturities, trading ​ 532.1 ​ ​ — ​ 0.5 ​ 531.6 ​ — ​ Equity securities ​ 2,013.4 ​ ​ — ​ 659.7 ​ 1,353.7 ​ — ​ Derivative assets (2) ​ 463.5 ​ ​ — ​ — ​ 462.9 ​ 0.6 ​ Other investments ​ 746.3 ​ ​ 75.7 ​ 252.8 ​ 385.9 ​ 31.9 ​ Cash equivalents ​ 1,466.4 ​ ​ — ​ 38.3 ​ 1,428.1 ​ — ​ Sub-total excluding separate account assets ​ 83,932.0 ​ ​ 75.7 ​ 2,720.7 ​ 80,742.7 ​ 392.9 ​ Separate account assets ​ 175,951.4 ​ ​ 155.8 ​ 102,550.5 ​ 64,351.9 ​ 8,893.2 ​ Total assets ​ $ 259,883.4 ​ $ 231.5 ​ $ 105,271.2 ​ $ 145,094.6 ​ $ 9,286.1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts (3) ​ $ (467.8) ​ $ — ​ $ — ​ $ — ​ $ (467.8) ​ Derivative liabilities (2) ​ ​ (186.1) ​ ​ — ​ ​ — ​ ​ (180.4) ​ ​ (5.7) ​ Other liabilities ​ (0.4) ​ ​ — ​ — ​ (0.4) ​ — ​ Total liabilities ​ $ (654.3) ​ $ — ​ $ — ​ $ (180.8) ​ $ (473.5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net assets ​ $ 259,229.1 ​ $ 231.5 ​ $ 105,271.2 ​ $ 144,913.8 ​ $ 8,812.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Assets/ ​ Amount ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (liabilities) ​ measured at ​ Fair value hierarchy level ​ ​ ​ measured at ​ net asset ​ ​ ​ ​ fair value value (4) Level 1 Level 2 Level 3 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agencies ​ $ 1,724.2 ​ $ — ​ $ 1,320.0 ​ $ 404.2 ​ $ — ​ Non-U.S. governments ​ 996.2 ​ ​ — ​ 1.4 ​ 994.8 ​ — ​ States and political subdivisions ​ 7,490.0 ​ ​ — ​ — ​ 7,490.0 ​ — ​ Corporate ​ 40,647.4 ​ ​ — ​ 18.5 ​ 40,547.2 ​ 81.7 ​ Residential mortgage-backed pass-through securities ​ 2,982.4 ​ ​ — ​ — ​ 2,982.4 ​ — ​ Commercial mortgage-backed securities ​ 4,850.2 ​ ​ — ​ — ​ 4,837.3 ​ 12.9 ​ Collateralized debt obligations (1) ​ 3,215.3 ​ ​ — ​ — ​ 3,016.3 ​ 199.0 ​ Other debt obligations ​ 8,200.5 ​ ​ — ​ — ​ 8,109.2 ​ 91.3 ​ Total fixed maturities, available-for-sale ​ 70,106.2 ​ ​ — ​ 1,339.9 ​ 68,381.4 ​ 384.9 ​ Fixed maturities, trading ​ 675.9 ​ ​ — ​ 0.5 ​ 675.1 ​ 0.3 ​ Equity securities ​ 1,879.4 ​ ​ — ​ 645.8 ​ 1,233.6 ​ — ​ Derivative assets (2) ​ 294.7 ​ ​ — ​ — ​ 265.4 ​ 29.3 ​ Other investments ​ 796.0 ​ ​ 78.3 ​ 335.2 ​ 343.5 ​ 39.0 ​ Cash equivalents ​ 1,299.0 ​ ​ — ​ 40.9 ​ 1,258.1 ​ — ​ Sub-total excluding separate account assets ​ 75,051.2 ​ ​ 78.3 ​ 2,362.3 ​ 72,157.1 ​ 453.5 ​ Separate account assets ​ 165,468.0 ​ ​ 129.0 ​ 95,652.5 ​ 60,718.5 ​ 8,968.0 ​ Total assets ​ $ 240,519.2 ​ $ 207.3 ​ $ 98,014.8 ​ $ 132,875.6 ​ $ 9,421.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts (3) ​ $ (214.2) ​ $ — ​ $ — ​ $ — ​ $ (214.2) ​ Derivative liabilities (2) ​ ​ (217.7) ​ ​ — ​ ​ — ​ ​ (201.4) ​ ​ (16.3) ​ Other liabilities (3) ​ (98.9) ​ ​ — ​ — ​ (98.9) ​ — ​ Total liabilities ​ $ (530.8) ​ $ — ​ $ — ​ $ (300.3) ​ $ (230.5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net assets ​ $ 239,988.4 ​ $ 207.3 ​ $ 98,014.8 ​ $ 132,575.3 ​ $ 9,191.0 ​ (1) Primarily consists of collateralized loan obligations backed by secured corporate loans. (2) Within the consolidated statements of financial position, derivative assets are reported with other investments and derivative liabilities are reported with other liabilities. The amounts are presented gross in the tables above to reflect the presentation on the consolidated statements of financial position; however, are presented net for purposes of the rollforward in the Changes in Level 3 Fair Value Measurements tables. Refer to Note 5, Derivative Financial Instruments, for further information on fair value by class of derivative instruments. (3) Includes bifurcated embedded derivatives that are reported at net asset (liability) fair value within the same line item in the consolidated statements of financial position in which the host contract is reported. (4) Certain investments are measured at fair value using the NAV per share (or its equivalent) practical expedient and have not been classified in the fair value hierarchy. Other investments using the NAV practical expedient consist of certain fund interests that are restricted until maturity with unfunded commitments totaling $15.1 million and $19.9 million as of December 31, 2020 and December 31, 2019, respectively. Separate account assets using the NAV practical expedient consist of hedge funds with varying investment strategies that also have a variety of redemption terms and conditions. We do not have unfunded commitments associated with these hedge funds.
Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ Total realized/unrealized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gains (losses) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ ​ Net ​ ​ ​ ​ ​ ​ ​ Ending ​ ​ (liability) ​ ​ ​ purchases, ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ balance ​ Included ​ Included in ​ sales, ​ ​ ​ ​ ​ ​ ​ (liability) ​ ​ as of ​ in net ​ other ​ issuances ​ Transfers ​ Transfers ​ balance as of ​ ​ January 1, ​ income ​ comprehensive ​ and ​ into ​ out of ​ December 31, ​ 2020 (2) income (3) settlements (4) Level 3 Level 3 2020 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 81.7 ​ $ (0.9) ​ $ 5.2 ​ $ 118.0 ​ $ 342.0 ​ $ (255.2) ​ $ 290.8 Commercial mortgage-backed securities ​ 12.9 ​ (1.3) ​ 1.4 ​ ​ (0.1) ​ 0.3 ​ — ​ 13.2 Collateralized debt obligations ​ 199.0 ​ (2.3) ​ (21.9) ​ ​ 183.0 ​ — ​ (330.6) ​ 27.2 Other debt obligations ​ 91.3 ​ — ​ (1.4) ​ ​ (37.9) ​ 46.1 ​ (68.9) ​ 29.2 Total fixed maturities, available-for-sale ​ 384.9 ​ (4.5) ​ (16.7) ​ ​ 263.0 ​ 388.4 ​ (654.7) ​ 360.4 Fixed maturities, trading ​ ​ 0.3 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (0.3) ​ ​ — Other investments ​ 39.0 ​ 6.3 ​ (2.9) ​ ​ (10.5) ​ — ​ — ​ 31.9 Separate account assets (1) ​ 8,968.0 ​ 463.7 ​ — ​ ​ (538.5) ​ — ​ — ​ 8,893.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ (214.2) ​ (254.9) ​ (0.3) ​ ​ 1.6 ​ — ​ — ​ (467.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ 13.0 ​ 11.8 ​ — ​ ​ (3.4) ​ — ​ ​ (26.5) ​ (5.1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ ​ ​ Total realized/unrealized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gains (losses) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending ​ ​ (liability) ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ balance ​ ​ ​ Included in ​ sales, ​ ​ ​ ​ ​ ​ ​ (liability) ​ ​ as of ​ Included ​ other ​ issuances ​ Transfers ​ Transfers ​ balance as of ​ ​ January 1, ​ in net ​ comprehensive ​ and ​ into ​ out of ​ December 31, ​ 2019 income (2) income (3) settlements (4) Level 3 Level 3 2019 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ 4.6 ​ $ — ​ $ — ​ $ (4.6) ​ $ — ​ $ — ​ $ — Corporate ​ 57.9 ​ — ​ 2.5 ​ ​ 17.2 ​ 4.1 ​ — ​ 81.7 Commercial mortgage-backed securities ​ 9.5 ​ (3.8) ​ 3.4 ​ ​ 2.4 ​ 3.7 ​ (2.3) ​ 12.9 Collateralized debt obligations ​ 8.3 ​ (2.6) ​ 0.9 ​ ​ 122.5 ​ 69.9 ​ — ​ 199.0 Other debt obligations ​ 58.5 ​ — ​ 0.8 ​ ​ 100.0 ​ 8.3 ​ (76.3) ​ 91.3 Total fixed maturities, available-for-sale ​ 138.8 ​ (6.4) ​ 7.6 ​ ​ 237.5 ​ 86.0 ​ (78.6) ​ 384.9 Fixed maturities, trading ​ — ​ — ​ — ​ ​ 0.3 ​ — ​ — ​ 0.3 Other investments ​ 17.2 ​ 6.0 ​ — ​ ​ 5.8 ​ 10.0 ​ — ​ 39.0 Separate account assets (1) ​ 8,615.5 ​ 739.9 ​ — ​ ​ (214.2) ​ — ​ (173.2) ​ 8,968.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ (45.2) ​ (145.5) ​ (0.2) ​ ​ (23.3) ​ — ​ — ​ (214.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 3.1 ​ ​ (0.8) ​ ​ — ​ ​ 10.7 ​ ​ — ​ ​ — ​ ​ 13.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ ​ ​ ​ Total realized/unrealized ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ gains (losses) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Beginning ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ending ​ ​ (liability) ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ asset/ ​ ​ balance ​ ​ ​ Included in ​ sales, ​ ​ ​ ​ ​ ​ ​ (liability) ​ ​ as of ​ Included ​ other ​ issuances ​ Transfers ​ Transfers ​ balance as of ​ ​ January 1, ​ in net ​ comprehensive ​ and ​ into ​ out of ​ December 31, ​ 2018 income (2) income (3) settlements (4) Level 3 Level 3 2018 ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ 7.4 ​ $ — ​ $ (0.1) ​ $ (1.4) ​ $ — ​ $ (1.3) ​ $ 4.6 Corporate ​ 128.0 ​ (1.0) ​ (0.1) ​ ​ (15.2) ​ 1.0 ​ (54.8) ​ 57.9 Commercial mortgage-backed securities ​ 10.6 ​ (3.5) ​ 0.2 ​ ​ 0.1 ​ 3.6 ​ (1.5) ​ 9.5 Collateralized debt obligations ​ 125.0 ​ (0.9) ​ 0.2 ​ ​ 66.3 ​ 54.7 ​ (237.0) ​ 8.3 Other debt obligations ​ 2.3 ​ — ​ (0.2) ​ ​ 147.4 ​ — ​ (91.0) ​ 58.5 Total fixed maturities, available-for-sale ​ 273.3 ​ (5.4) ​ — ​ ​ 197.2 ​ 59.3 ​ (385.6) ​ 138.8 Fixed maturities, trading ​ — ​ — ​ — ​ ​ 3.7 ​ — ​ (3.7) ​ — Equity securities ​ ​ 2.7 ​ ​ 12.9 ​ ​ — ​ ​ (15.6) ​ ​ — ​ ​ — ​ ​ — Other investments ​ 6.5 ​ 1.7 ​ — ​ ​ 9.0 ​ — ​ — ​ 17.2 Separate account assets (1) ​ 7,651.4 ​ 869.5 ​ (0.3) ​ ​ 133.7 ​ 2.3 ​ (41.1) ​ 8,615.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ (160.3) ​ 107.5 ​ 0.1 ​ ​ 7.5 ​ — ​ — ​ (45.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 18.1 ​ ​ (20.2) ​ ​ — ​ ​ 5.2 ​ ​ — ​ ​ — ​ ​ 3.1 (1) Gains and losses for separate account assets do not impact net income as the change in value of separate account assets is offset by a change in value of separate account liabilities. Foreign currency translation adjustments related to the Principal International segment separate account assets are recorded in AOCI and are offset by foreign currency translation adjustments of the corresponding separate account liabilities. (2) Both realized gains (losses) and mark-to-market unrealized gains (losses) are generally reported in net realized capital gains (losses) within the consolidated statements of operations. Realized and unrealized gains (losses) on certain securities with an investment objective to realize economic value through mark-to-market changes are reported in net investment income within the consolidated statements of operations. Changes in unrealized gains (losses) included in net income relating to positions still held were: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Assets ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ Commercial mortgage-backed securities ​ $ (1.2) ​ $ (2.9) ​ $ (1.9) Collateralized debt obligations ​ (2.2) ​ (2.6) ​ (0.9) Total fixed maturities, available-for-sale ​ (3.4) ​ (5.5) ​ (2.8) Other investments ​ 5.3 ​ 6.0 ​ 1.7 Separate account assets ​ 385.5 ​ 697.1 ​ 829.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ Investment and universal life contracts ​ (262.1) ​ (146.0) ​ 109.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ Net derivative assets (liabilities) ​ 9.9 ​ 5.3 ​ (18.4) ​ (3) Includes foreign currency translation adjustments related to our Principal International segment. Changes in unrealized gains (losses) included in OCI relating to positions still held were: ​ ​ ​ ​ ​ For the year ended ​ ​ December 31, 2020 ​ ​ ​ (in millions) Assets ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ Corporate ​ $ 11.9 Commercial mortgage-backed securities ​ ​ 1.5 Collateralized debt obligations ​ ​ (0.3) Total fixed maturities, available-for-sale ​ ​ 13.1 Other investments ​ ​ (2.9) ​ ​ ​ ​ Liabilities ​ ​ ​ Investment and universal life contracts ​ ​ (0.3) ​ (4) Gross purchases, sales, issuances and settlements were: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ sales, issuances ​ ​ Purchases Sales Issuances Settlements and settlements ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 169.2 ​ $ (5.5) ​ $ — ​ $ (45.7) ​ $ 118.0 ​ Commercial mortgage-backed securities ​ — ​ — ​ — ​ (0.1) ​ (0.1) ​ Collateralized debt obligations ​ 182.5 ​ — ​ — ​ 0.5 ​ 183.0 ​ Other debt obligations ​ 14.3 ​ — ​ — ​ (52.2) ​ (37.9) ​ Total fixed maturities, available-for-sale ​ 366.0 ​ (5.5) ​ — ​ (97.5) ​ 263.0 ​ Other investments ​ 0.5 ​ (11.0) ​ — ​ — ​ (10.5) ​ Separate account assets (5) ​ 309.2 ​ ​ (658.2) ​ ​ (396.1) ​ 206.6 ​ (538.5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ — ​ — ​ (23.0) ​ 24.6 ​ 1.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ — ​ (3.4) ​ — ​ — ​ (3.4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ sales, issuances ​ ​ Purchases Sales Issuances Settlements and settlements ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ — ​ $ — ​ $ — ​ $ (4.6) ​ $ (4.6) ​ Corporate ​ 41.9 ​ (1.4) ​ — ​ (23.3) ​ 17.2 ​ Commercial mortgage-backed securities ​ 2.4 ​ — ​ — ​ — ​ 2.4 ​ Collateralized debt obligations ​ 124.7 ​ — ​ — ​ (2.2) ​ 122.5 ​ Other debt obligations ​ 107.7 ​ — ​ — ​ (7.7) ​ 100.0 ​ Total fixed maturities, available-for-sale ​ 276.7 ​ (1.4) ​ — ​ (37.8) ​ 237.5 ​ Fixed maturities, trading ​ ​ 0.5 ​ ​ — ​ ​ — ​ ​ (0.2) ​ ​ 0.3 ​ Other investments ​ 10.7 ​ (4.9) ​ — ​ — ​ 5.8 ​ Separate account assets (5) ​ 279.1 ​ ​ (526.4) ​ ​ (280.4) ​ 313.5 ​ (214.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ — ​ — ​ (33.4) ​ 10.1 ​ (23.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 1.9 ​ 8.8 ​ — ​ — ​ 10.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net purchases, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ sales, issuances ​ ​ Purchases Sales Issuances Settlements and settlements ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ — ​ $ — ​ $ — ​ $ (1.4) ​ $ (1.4) ​ Corporate ​ 12.9 ​ (10.1) ​ — ​ (18.0) ​ (15.2) ​ Commercial mortgage-backed securities ​ — ​ — ​ — ​ 0.1 ​ 0.1 ​ Collateralized debt obligations ​ 93.6 ​ — ​ — ​ (27.3) ​ 66.3 ​ Other debt obligations ​ 152.0 ​ — ​ — ​ (4.6) ​ 147.4 ​ Total fixed maturities, available-for-sale ​ 258.5 ​ (10.1) ​ — ​ (51.2) ​ 197.2 ​ Fixed maturities, trading ​ ​ 3.7 ​ — ​ — ​ ​ — ​ ​ 3.7 ​ Equity securities ​ — ​ (15.6) ​ — ​ — ​ (15.6) ​ Other investments ​ 9.0 ​ — ​ — ​ — ​ 9.0 ​ Separate account assets (5) ​ 743.0 ​ ​ (608.4) ​ ​ (206.5) ​ 205.6 ​ 133.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts ​ — ​ — ​ 2.8 ​ 4.7 ​ 7.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ ​ 1.8 ​ 3.4 ​ — ​ — ​ 5.2 ​ (5) Issuances and settlements include amounts related to mortgage encumbrances associated with real estate in our separate accounts.
Transfers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2020 ​ ​ ​ Transfers out ​ Transfers out ​ Transfers out ​ Transfers out ​ ​ ​ of Level 1 into ​ of Level 2 into ​ of Level 3 into ​ of Level 3 into ​ ​ Level 3 Level 3 Level 1 Level 2 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ — ​ $ 342.0 ​ $ — ​ $ 255.2 ​ Commercial mortgage-backed securities ​ — ​ 0.3 ​ — ​ — ​ Collateralized debt obligations ​ — ​ ​ — ​ ​ — ​ ​ 330.6 ​ Other debt obligations ​ — ​ ​ 46.1 ​ ​ — ​ ​ 68.9 ​ Total fixed maturities, available-for-sale ​ ​ — ​ ​ 388.4 ​ ​ — ​ ​ 654.7 ​ Fixed maturities, trading ​ — ​ ​ — ​ ​ — ​ ​ 0.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivatives ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net derivative assets (liabilities) ​ — ​ ​ — ​ ​ — ​ ​ 26.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2019 ​ ​ ​ Transfers out ​ Transfers out ​ Transfers out ​ Transfers out ​ ​ ​ of Level 1 into ​ of Level 2 into ​ of Level 3 into ​ of Level 3 into ​ ​ Level 3 Level 3 Level 1 Level 2 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ — ​ $ 4.1 ​ $ — ​ $ — ​ Commercial mortgage-backed securities ​ — ​ 3.7 ​ — ​ 2.3 ​ Collateralized debt obligations ​ — ​ ​ 69.9 ​ ​ — ​ ​ — ​ Other debt obligations ​ — ​ ​ 8.3 ​ ​ — ​ ​ 76.3 ​ Total fixed maturities, available-for-sale ​ ​ — ​ ​ 86.0 ​ ​ — ​ ​ 78.6 ​ Other investments ​ ​ — ​ ​ 10.0 ​ ​ — ​ ​ — ​ Separate account assets ​ — ​ ​ — ​ ​ — ​ ​ 173.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, 2018 ​ ​ ​ Transfers out ​ Transfers out ​ Transfers out ​ Transfers out ​ ​ ​ of Level 1 into ​ of Level 2 into ​ of Level 3 into ​ of Level 3 into ​ ​ Level 3 Level 3 Level 1 Level 2 ​ ​ (in millions) ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for- sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-U.S. governments ​ $ — ​ $ — ​ $ — ​ $ 1.3 ​ Corporate ​ — ​ 1.0 ​ — ​ 54.8 ​ Commercial mortgage-backed securities ​ — ​ 3.6 ​ — ​ 1.5 ​ Collateralized debt obligations ​ ​ — ​ ​ 54.7 ​ ​ — ​ ​ 237.0 ​ Other debt obligations ​ — ​ — ​ — ​ 91.0 ​ Total fixed maturities, available-for-sale ​ ​ — ​ ​ 59.3 ​ ​ — ​ ​ 385.6 ​ Fixed maturities, trading ​ ​ — ​ ​ — ​ ​ — ​ ​ 3.7 ​ Separate account assets ​ — ​ 2.3 ​ 0.2 ​ 40.9 ​
Quantitative Information about Level 3 Fair Value Measurements (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Assets / ​ ​ ​ ​ ​ ​ ​ ​ ​ (liabilities) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ measured at ​ Valuation ​ Unobservable ​ Input/range of ​ Weighted ​ ​ fair value ​ technique(s) ​ input description ​ inputs ​ average ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 286.1 ​ Discounted cash flow ​ Discount rate (1) ​ 0.9 %- 11.7 % 7.3 % ​ ​ ​ ​ ​ ​ ​ Illiquidity premium ​ 0 basis points ("bps")- 60 bps 19 bps ​ ​ ​ ​ ​ ​ ​ Comparability adjustment ​ 0 bps- 769 bps 359 bps ​ ​ ​ ​ ​ ​ ​ Potential loss severity ​ 0.0 %- 54.6 % 0.2 % ​ ​ ​ ​ ​ ​ ​ Probability of default ​ 0.0 %- 100.0 % 0.3 % Commercial mortgage-backed securities ​ ​ 1.1 ​ Discounted cash flow ​ Probability of default ​ ​ ​ 100.0 % 100.0 % ​ ​ ​ ​ ​ ​ ​ Potential loss severity ​ ​ ​ 78.4 % 78.4 % Collateralized debt obligations ​ ​ 0.7 ​ Discounted cash flow ​ Potential loss severity ​ ​ ​ 40.5 % 40.5 % ​ ​ ​ ​ ​ ​ ​ Probability of default ​ ​ ​ 100.0 % 100.0 % Other debt obligations ​ 0.8 ​ Discounted cash flow ​ Discount rate (1) ​ ​ ​ 10.0 % 10.0 % ​ ​ ​ ​ ​ ​ ​ Illiquidity premium ​ ​ ​ 500 bps 500 bps Other investments ​ ​ 30.4 ​ Discounted cash flow - other investments ​ Discount rate (1) ​ 25.0 %- 30.0 % 27.5 % ​ ​ ​ ​ ​ ​ ​ Terminal earnings before interest, taxes, depreciation and amortization multiple ​ 3.8 x- 4.7 x 4.2 x ​ ​ ​ ​ ​ Market comparables - other investments ​ Revenue multiples (2) ​ 6.0 x- 8.0 x 7.0 x ​ ​ ​ ​ ​ Discounted cash flow - real estate ​ Discount rate (1) ​ ​ ​ 6.5 % 6.5 % ​ ​ ​ ​ ​ ​ ​ Terminal capitalization rate ​ ​ ​ 5.3 % 5.3 % ​ ​ ​ ​ ​ ​ ​ Average market rent growth rate ​ ​ ​ 2.6 % 2.6 % ​ ​ ​ ​ ​ Discounted cash flow - real estate debt ​ Loan to value ​ ​ ​ 52.6 % 52.6 % ​ ​ ​ ​ ​ ​ ​ Credit spread ​ ​ ​ 3.3 % 3.3 % Separate account assets ​ 8,893.2 ​ Discounted cash flow - mortgage loans ​ Discount rate (1) ​ ​ ​ 1.2 % 1.2 % ​ ​ ​ ​ ​ ​ ​ Illiquidity premium ​ ​ ​ 60 bps 60 bps ​ ​ ​ ​ ​ ​ ​ Credit spread rate ​ ​ ​ 110 bps 110 bps ​ ​ ​ ​ ​ Discounted cash flow - real estate ​ Discount rate (1) ​ 5.6 %- 11.9 % 6.9 % ​ ​ ​ ​ ​ ​ ​ Terminal capitalization rate ​ 4.5 %- 9.3 % 5.7 % ​ ​ ​ ​ ​ ​ ​ Average market rent growth rate ​ 1.5 %- 4.8 % 3.0 % ​ ​ ​ ​ ​ Discounted cash flow - real estate debt ​ Loan to value ​ 6.3 %- 74.2 % 47.5 % ​ ​ ​ ​ ​ ​ ​ Market interest rate ​ 2.0 %- 5.0 % 3.4 % Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts (6) ​ (467.8) ​ Discounted cash flow ​ Long duration interest rate ​ 1.2 %- 1.4 % (3) 1.3 % ​ ​ ​ ​ ​ ​ ​ Long-term equity market volatility ​ 17.6 %- 26.9 % 19.6 % ​ ​ ​ ​ ​ ​ ​ Nonperformance risk ​ 0.1 %- 1.4 % 0.9 % ​ ​ ​ ​ ​ ​ ​ Utilization rate ​ See note (4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Lapse rate ​ 0.0 %- 16.0 % 5.8 % ​ ​ ​ ​ ​ ​ ​ Mortality rate ​ See note (5) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ Assets / ​ ​ ​ ​ ​ ​ ​ ​ ​ (liabilities) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ measured at ​ Valuation ​ Unobservable ​ Input/range of ​ Weighted ​ ​ fair value ​ technique(s) ​ input description ​ inputs ​ average ​ ​ (in millions) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate ​ $ 72.5 ​ Discounted cash flow ​ Discount rate (1) ​ 1.9 %- 5.1 % 3.8 % ​ ​ ​ ​ ​ ​ ​ Illiquidity premium ​ 0 bps- 410 bps 152 bps Commercial mortgage-backed securities ​ ​ 2.4 ​ Discounted cash flow ​ Probability of default ​ ​ ​ 100.0 % 100.0 % ​ ​ ​ ​ ​ ​ ​ Potential loss severity ​ ​ ​ 53.1 % 53.1 % Collateralized debt obligations ​ ​ 108.7 ​ Discounted cash flow ​ Discount rate (1) ​ 2.9 %- 10.0 % 3.4 % ​ ​ ​ ​ ​ ​ ​ Potential loss severity ​ ​ ​ 23.0 % 23.0 % ​ ​ ​ ​ ​ ​ ​ Probability of default ​ ​ ​ 100.0 % 100.0 % Other debt obligations ​ 1.2 ​ Discounted cash flow ​ Discount rate (1) ​ ​ ​ 5.0 % 5.0 % ​ ​ ​ ​ ​ ​ ​ Illiquidity premium ​ ​ ​ 500 bps 500 bps Other investments ​ ​ 14.8 ​ Discounted cash flow ​ Discount rate (1) ​ 25.0 %- 30.0 % 27.5 % ​ ​ ​ ​ ​ ​ ​ Terminal earnings before interest, taxes, depreciation and amortization multiple ​ 3.5 x- 4.5 x 4.0 x ​ ​ ​ ​ ​ Market comparables ​ Revenue multiples (2) ​ 0.8 x- 7.0 x 4.1 x Separate account assets ​ 8,966.2 ​ Discounted cash flow - mortgage loans ​ Discount rate (1) ​ ​ ​ 2.8 % 2.8 % ​ ​ ​ ​ ​ ​ ​ Illiquidity premium ​ ​ ​ 60 bps 60 bps ​ ​ ​ ​ ​ ​ ​ Credit spread rate ​ ​ ​ 120 bps 120 bps ​ ​ ​ ​ ​ Discounted cash flow - real estate ​ Discount rate (1) ​ 5.5 %- 11.8 % 6.7 % ​ ​ ​ ​ ​ ​ ​ Terminal capitalization rate ​ 4.5 %- 9.3 % 5.7 % ​ ​ ​ ​ ​ ​ ​ Average market rent growth rate ​ 2.0 %- 4.7 % 3.0 % ​ ​ ​ ​ ​ Discounted cash flow - real estate debt ​ Loan to value ​ 8.0 %- 80.4 % 45.9 % ​ ​ ​ ​ ​ ​ ​ Market interest rate ​ 3.2 %- 5.8 % 3.6 % Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Investment and universal life contracts (6) ​ (214.2) ​ Discounted cash flow ​ Long duration interest rate ​ 2.0 %- 2.1 % (3) ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term equity market volatility ​ 15.0 %- 26.9 % ​ ​ ​ ​ ​ ​ ​ ​ ​ Nonperformance risk ​ 0.2 %- 1.3 % ​ ​ ​ ​ ​ ​ ​ ​ ​ Utilization rate ​ See note (4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Lapse rate ​ 0.0 %- 18.0 % ​ ​ ​ ​ ​ ​ ​ ​ ​ Mortality rate ​ See note (5) ​ ​ ​ (1) Represents market comparable interest rate or an index adjusted rate used as the base rate in the discounted cash flow analysis prior to any illiquidity or other adjustments, where applicable. (2) Revenue multiples are amounts used when we have determined market participants would use such multiples to value the investments. (3) Represents the range of rate curves used in the valuation analysis that we have determined market participants would use when pricing the instrument. Derived from interpolation between various observable swap rates. (4) This input factor is the number of contractholders taking withdrawals as well as the amount and timing of the withdrawals and a range does not provide a meaningful presentation. (5) This input is based on an appropriate industry mortality table and a range does not provide a meaningful presentation. (6) Includes bifurcated embedded derivatives that are reported at net asset (liability) fair value within the same line item in the consolidated statements of financial position in which the host contract is reported.
Fair Value Option (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) ​ Real estate ventures (1) ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 28.5 ​ $ 22.8 ​ (1) Reported with other investments in the consolidated statements of financial position. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Commercial mortgage loans of consolidated VIEs ​ ​ ​ Change in fair value pre-tax gain (loss) (1) (2) ​ $ — ​ $ 0.1 ​ $ (0.2) ​ Interest income (3) ​ ​ — ​ ​ 0.3 ​ ​ 0.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Real estate ventures ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in fair value pre-tax gain (4) ​ ​ 5.3 ​ ​ 6.0 ​ ​ 1.7 ​ (1) None of the change in fair value related to instrument-specific credit risk. (2) Reported in net realized capital gains (losses) on the consolidated statements of operations. (3) Reported in net investment income on the consolidated statements of operations and recorded based on the effective interest rates as determined at the closing of the loan. (4) Reported in net investment income on the consolidated statements of operations.
Financial Instruments Not Reported at Fair Value (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value hierarchy level ​ ​ Carrying amount Fair value Level 1 Level 2 Level 3 ​ ​ (in millions) Assets (liabilities) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mortgage loans ​ $ 17,343.0 ​ $ 18,762.6 ​ $ — ​ $ — ​ $ 18,762.6 ​ Policy loans ​ 784.0 ​ 1,037.7 ​ — ​ — ​ 1,037.7 ​ Other investments ​ 347.2 ​ 338.5 ​ — ​ 247.1 ​ 91.4 ​ Cash and cash equivalents ​ 1,383.4 ​ 1,383.4 ​ 1,369.7 ​ 13.7 ​ — ​ Investment contracts ​ (35,449.9) ​ (36,738.7) ​ — ​ (5,276.9) ​ (31,461.8) ​ Short-term debt ​ (84.7) ​ (84.7) ​ — ​ (84.7) ​ — ​ Long-term debt ​ (4,279.2) ​ (4,949.9) ​ — ​ (4,908.7) ​ (41.2) ​ Separate account liabilities ​ (160,316.4) ​ (159,129.2) ​ — ​ — ​ (159,129.2) ​ Bank deposits (1) ​ (423.5) ​ (429.7) ​ — ​ (429.7) ​ — ​ Cash collateral payable ​ (224.6) ​ (224.6) ​ (224.6) ​ — ​ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ Fair value hierarchy level ​ Carrying amount Fair value Level 1 Level 2 Level 3 ​ ​ (in millions) Assets (liabilities) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mortgage loans ​ $ 16,486.9 ​ $ 17,214.7 ​ $ — ​ $ — ​ $ 17,214.7 ​ Policy loans ​ 798.0 ​ 1,030.8 ​ — ​ — ​ 1,030.8 ​ Other investments ​ 278.8 ​ 273.1 ​ — ​ 180.3 ​ 92.8 ​ Cash and cash equivalents ​ 1,216.9 ​ 1,216.9 ​ 1,193.3 ​ 23.6 ​ — ​ Investment contracts ​ (33,922.2) ​ (34,001.3) ​ — ​ (4,304.5) ​ (29,696.8) ​ Short-term debt ​ (93.4) ​ (93.4) ​ — ​ (93.4) ​ — ​ Long-term debt ​ (3,734.1) ​ (4,122.9) ​ — ​ (4,015.3) ​ (107.6) ​ Separate account liabilities ​ (151,132.4) ​ (149,955.6) ​ — ​ — ​ (149,955.6) ​ Bank deposits (1) ​ (469.6) ​ (468.3) ​ — ​ (468.3) ​ — ​ Cash collateral payable ​ (156.8) ​ (156.8) ​ (156.8) ​ — ​ — ​ (1) Excludes deposit liabilities without defined or contractual maturities.

Statutory Insurance Financial_2

Statutory Insurance Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Statutory Insurance Financial Information
Statutory Net Income and Statutory Capital and Surplus of Principal Life (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of or for the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Statutory net income ​ $ 915.9 ​ $ 989.3 ​ $ 1,017.6 ​ Statutory capital and surplus ​ ​ 5,682.4 ​ 5,193.4 ​ 5,319.6 ​

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Information
Reconciliation of Assets from Segment to Consolidated (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ (in millions) Assets: ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 207,288.4 ​ $ 192,698.1 ​ Principal Global Investors ​ ​ 2,294.3 ​ 2,363.3 ​ Principal International ​ ​ 51,707.6 ​ 48,857.6 ​ U.S. Insurance Solutions ​ ​ 31,438.9 ​ 28,669.6 ​ Corporate ​ ​ 3,898.5 ​ 3,499.2 ​ Total consolidated assets ​ $ 296,627.7 ​ $ 276,087.8 ​
Reconciliation of Operating Revenues and Pre-tax Operating Earnings (Losses) by Segment (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Operating revenues by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions – Fee ​ $ 2,149.8 ​ $ 2,003.0 ​ $ 1,783.7 ​ Retirement and Income Solutions – Spread ​ ​ 5,353.7 ​ ​ 6,951.4 ​ ​ 5,493.3 ​ Total Retirement and Income Solutions (1) ​ ​ 7,503.5 ​ ​ 8,954.4 ​ ​ 7,277.0 ​ Principal Global Investors (2) ​ ​ 1,539.1 ​ 1,505.8 ​ 1,736.3 ​ Principal International ​ ​ 1,096.8 ​ 1,523.2 ​ 1,372.9 ​ U.S. Insurance Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Specialty Benefits insurance ​ ​ 2,525.4 ​ 2,493.6 ​ 2,326.4 ​ Individual Life insurance ​ ​ 1,955.0 ​ 1,955.6 ​ 1,763.6 ​ Eliminations ​ ​ (0.2) ​ (0.2) ​ (0.2) ​ Total U.S. Insurance Solutions ​ ​ 4,480.2 ​ 4,449.0 ​ 4,089.8 ​ Corporate ​ ​ (39.7) ​ (39.3) ​ (51.2) ​ Total segment operating revenues ​ ​ 14,579.9 ​ 16,393.1 ​ 14,424.8 ​ Net realized capital gains (losses), net of related revenue adjustments ​ ​ 195.3 ​ (98.5) ​ (132.3) ​ Adjustments related to equity method investments ​ ​ (33.5) ​ ​ (72.5) ​ ​ (55.3) ​ Total revenues per consolidated statements of operations ​ $ 14,741.7 ​ $ 16,222.1 ​ $ 14,237.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-tax operating earnings (losses) by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 966.9 ​ $ 874.0 ​ $ 922.2 ​ Principal Global Investors ​ ​ 512.9 ​ 483.3 ​ 562.1 ​ Principal International ​ ​ 243.6 ​ 390.7 ​ 272.6 ​ U.S. Insurance Solutions ​ ​ 239.9 ​ 521.6 ​ 467.0 ​ Corporate ​ ​ (326.4) ​ (380.3) ​ (269.4) ​ Total segment pre-tax operating earnings ​ ​ 1,636.9 ​ 1,889.3 ​ 1,954.5 ​ Pre-tax net realized capital gains (losses), as adjusted (3) ​ ​ 63.6 ​ (140.9) ​ (126.4) ​ Adjustments related to equity method investments and noncontrolling interest ​ ​ (7.0) ​ ​ (55.1) ​ ​ (43.7) ​ Income before income taxes per consolidated statements of operations ​ $ 1,693.5 ​ $ 1,693.3 ​ $ 1,784.4 ​ (1) Reflects inter-segment revenues of $342.6 million, $357.8 million and $393.6 million for the years ended December 31, 2020, 2019 and 2018, respectively. (2) Reflects inter-segment revenues of $273.8 million, $264.9 million and $262.8 million for the years ended December 31, 2020, 2019 and 2018, respectively. ​ (3) Pre-tax net realized capital gains (losses), as adjusted, is derived as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Net realized capital gains (losses) ​ $ 302.6 ​ $ (52.8) ​ $ (75.4) ​ Derivative and hedging-related revenue adjustments ​ ​ (132.9) ​ (80.4) ​ (64.9) ​ Market value adjustments to fee revenues ​ ​ (1.6) ​ — ​ 0.1 ​ Adjustments related to equity method investments ​ ​ (1.5) ​ ​ 2.6 ​ ​ (5.4) ​ Adjustments related to sponsored investment funds ​ ​ 17.3 ​ ​ 23.6 ​ ​ 12.9 ​ Recognition of front-end fee revenue ​ ​ 11.4 ​ 8.5 ​ 0.4 ​ Net realized capital gains (losses), net of related revenue adjustments ​ ​ 195.3 ​ (98.5) ​ (132.3) ​ Amortization of deferred acquisition costs and other actuarial balances ​ ​ (26.8) ​ (40.8) ​ (27.0) ​ Capital (gains) losses distributed ​ ​ (49.9) ​ (68.2) ​ 14.4 ​ Market value adjustments of embedded derivatives ​ ​ (55.0) ​ 66.6 ​ 18.5 ​ Pre-tax net realized capital gains (losses), as adjusted (a) ​ $ 63.6 ​ $ (140.9) ​ $ (126.4) ​ (a) As adjusted before noncontrolling interest capital gains (losses).
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Income tax expense (benefit) by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 106.6 ​ $ 71.8 ​ $ 85.6 ​ Principal Global Investors ​ ​ 141.9 ​ 121.8 ​ 149.1 ​ Principal International ​ ​ 62.0 ​ 106.8 ​ 73.3 ​ U.S. Insurance Solutions ​ ​ 47.9 ​ 101.8 ​ 85.7 ​ Corporate ​ ​ (87.9) ​ (82.0) ​ (36.7) ​ Total segment income taxes from operating earnings ​ ​ 270.5 ​ 320.2 ​ 357.0 ​ Tax expense (benefit) related to net realized capital losses, as adjusted ​ ​ 28.2 ​ 1.3 ​ (71.4) ​ Certain adjustments related to equity method investments and noncontrolling interest ​ ​ (33.7) ​ ​ (72.3) ​ ​ (54.9) ​ Total income taxes per consolidated statements of operations ​ $ 265.0 ​ $ 249.2 ​ $ 230.7 ​ ​
Reconciliation of Depreciation and Amortization Expense from Segments to Consolidated (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Depreciation and amortization expense by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions ​ $ 69.1 ​ $ 48.2 ​ $ 32.5 ​ Principal Global Investors ​ ​ 21.6 ​ 18.9 ​ 21.9 ​ Principal International ​ ​ 56.0 ​ 58.6 ​ 59.6 ​ U.S. Insurance Solutions ​ ​ 25.1 ​ 25.0 ​ 26.2 ​ Corporate ​ ​ 14.8 ​ 16.1 ​ 10.8 ​ Total depreciation and amortization expense included in our consolidated statements of operations ​ $ 186.6 ​ $ 166.8 ​ $ 151.0 ​

Revenues from Contracts with _2

Revenues from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2020
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ (in millions) ​ Revenue from contracts with customers by segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Retirement and Income Solutions – Fee $ 591.2 $ 455.5 $ 252.4 ​ Retirement and Income Solutions – Spread ​ ​ 8.6 ​ 9.3 ​ 10.5 ​ Total Retirement and Income Solutions ​ ​ 599.8 ​ 464.8 ​ 262.9 ​ Principal Global Investors ​ ​ 1,511.2 ​ 1,456.7 ​ 1,700.5 ​ Principal International ​ ​ 439.2 ​ 462.2 ​ 477.1 ​ U.S. Insurance Solutions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Specialty Benefits insurance ​ ​ 14.8 ​ 14.9 ​ 14.8 ​ Individual Life insurance ​ ​ 48.6 ​ 51.2 ​ 42.4 ​ Eliminations ​ ​ (0.2) ​ (0.2) ​ (0.2) ​ Total U.S. Insurance Solutions ​ ​ 63.2 ​ 65.9 ​ 57.0 ​ Corporate ​ ​ 154.9 ​ 160.4 ​ 161.4 ​ Total segment revenue from contracts with customers ​ ​ 2,768.3 ​ 2,610.0 ​ 2,658.9 ​ Adjustments for fees and other revenues not within the scope of revenue recognition guidance (1) ​ ​ 1,733.0 ​ 1,791.4 ​ 1,614.4 ​ Pre-tax other adjustments (2) ​ ​ 9.8 ​ 8.5 ​ 0.5 ​ Total fees and other revenues per consolidated statements of operations $ 4,511.1 $ 4,409.9 $ 4,273.8 ​ (1) Fees and other revenues not within the scope of the revenue recognition guidance primarily represent revenue on contracts accounted for under the financial instruments or insurance contracts standards. (2) Pre-tax other adjustments relate to the recognition of deferred front-end fee revenues for sales charges on retirement and life insurance products and certain market value adjustments to fee revenues.
Retirement and Income Solutions | Retirement and Income Solutions - Fee
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Administrative service fee revenue (1) ​ $ 589.2 ​ $ 453.7 ​ $ 250.7 ​ Other fee revenue ​ 2.0 ​ 1.8 ​ 1.7 ​ Total revenues from contracts with customers ​ 591.2 ​ 455.5 ​ 252.4 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 1,130.4 ​ 1,139.0 ​ 1,132.9 ​ Total fees and other revenues ​ 1,721.6 ​ 1,594.5 ​ 1,385.3 ​ Premiums and other considerations ​ 5.0 ​ 3.5 ​ 4.0 ​ Net investment income ​ 423.2 ​ 405.0 ​ 394.4 ​ Total operating revenues ​ $ 2,149.8 ​ $ 2,003.0 ​ $ 1,783.7 ​ (1) Includes fee revenue for the Acquired Business in 2020 and 2019.
Retirement and Income Solutions | Retirement and Income Solutions - Spread
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) ​ Deposit account fee revenue ​ $ 8.4 ​ $ 9.3 ​ $ 10.5 ​ Commission income ​ ​ 0.2 ​ ​ — ​ ​ — ​ Total revenues from contracts with customers ​ 8.6 ​ 9.3 ​ 10.5 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 9.5 ​ 13.9 ​ 12.5 ​ Total fees and other revenues ​ 18.1 ​ 23.2 ​ 23.0 ​ Premiums and other considerations ​ 3,216.0 ​ 4,859.2 ​ 3,631.9 ​ Net investment income ​ 2,119.6 ​ 2,069.0 ​ 1,838.4 ​ Total operating revenues ​ $ 5,353.7 ​ $ 6,951.4 ​ $ 5,493.3 ​
Principal Global Investors
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Management fee revenue ​ $ 1,298.4 ​ $ 1,239.1 ​ $ 1,244.5 ​ Other fee revenue (1) ​ 212.8 ​ 217.6 ​ 456.0 ​ Total revenues from contracts with customers ​ ​ 1,511.2 ​ 1,456.7 ​ 1,700.5 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ ​ 22.3 ​ 38.5 ​ 30.4 ​ Total fees and other revenues ​ ​ 1,533.5 ​ 1,495.2 ​ 1,730.9 ​ Net investment income ​ ​ 5.6 ​ 10.6 ​ 5.4 ​ Total operating revenues ​ $ 1,539.1 ​ $ 1,505.8 ​ $ 1,736.3 ​ (1) During the third quarter of 2018, we recognized a $253.1 million accelerated performance fee resulting from the realignment of a real estate investment team.
Principal International
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ (in millions) ​ Management fee revenue ​ $ 435.3 ​ $ 459.3 ​ $ 472.1 ​ Other fee revenue ​ 3.9 ​ 2.9 ​ 5.0 ​ Total revenues from contracts with customers ​ 439.2 ​ 462.2 ​ 477.1 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 5.6 ​ 6.3 ​ 7.3 ​ Total fees and other revenues ​ 444.8 ​ 468.5 ​ 484.4 ​ Premiums and other considerations ​ 156.6 ​ 393.3 ​ 317.2 ​ Net investment income ​ 495.4 ​ 661.4 ​ 571.3 ​ Total operating revenues ​ $ 1,096.8 ​ $ 1,523.2 ​ $ 1,372.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues from contracts with customers by region: ​ ​ ​ ​ Latin America ​ $ 323.5 ​ $ 351.5 ​ $ 370.8 ​ Asia ​ 115.9 ​ 111.0 ​ 106.3 ​ Principal International corporate / regional offices ​ 0.9 ​ 0.9 ​ 0.9 ​ Eliminations ​ (1.1) ​ (1.2) ​ (0.9) ​ Total revenues from contracts with customers ​ $ 439.2 ​ $ 462.2 ​ $ 477.1 ​
U.S. Insurance Solutions
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Specialty Benefits insurance: ​ ​ ​ ​ Administrative service fees ​ $ 14.8 ​ $ 14.9 ​ $ 14.8 ​ Total revenues from contracts with customers ​ 14.8 ​ 14.9 ​ 14.8 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 19.3 ​ 19.6 ​ 20.6 ​ Total fees and other revenues ​ 34.1 ​ 34.5 ​ 35.4 ​ Premiums and other considerations ​ 2,330.7 ​ 2,292.7 ​ 2,134.1 ​ Net investment income ​ 160.6 ​ 166.4 ​ 156.9 ​ Total operating revenues ​ $ 2,525.4 ​ $ 2,493.6 ​ $ 2,326.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Individual Life insurance: ​ ​ ​ ​ Administrative service fees ​ $ 21.8 ​ $ 24.3 ​ $ 22.8 ​ Commission income ​ 26.8 ​ 26.9 ​ 19.6 ​ Total revenues from contracts with customers ​ 48.6 ​ 51.2 ​ 42.4 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ 849.8 ​ 875.9 ​ 727.0 ​ Total fees and other revenues ​ 898.4 ​ 927.1 ​ 769.4 ​ Premiums and other considerations ​ 329.1 ​ 317.9 ​ 322.4 ​ Net investment income ​ 727.5 ​ 710.6 ​ 671.8 ​ Total operating revenues ​ $ 1,955.0 ​ $ 1,955.6 ​ $ 1,763.6 ​
Corporate
Revenues from Contracts with Customers
Disaggregation of Revenues from Contracts with Customers (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ ​ 2020 2019 2018 ​ ​ ​ (in millions) ​ Commission income ​ $ 316.6 ​ $ 320.2 ​ $ 316.1 ​ Other fee revenue ​ ​ 59.1 ​ ​ 46.1 ​ ​ 35.4 ​ Eliminations ​ (220.8) ​ (205.9) ​ (190.1) ​ Total revenues from contracts with customers ​ 154.9 ​ 160.4 ​ 161.4 ​ Fees and other revenues not within the scope of revenue recognition guidance ​ (303.9) ​ (301.8) ​ (316.3) ​ Total fees and other revenues ​ (149.0) ​ (141.4) ​ (154.9) ​ Net investment income ​ 109.3 ​ 102.1 ​ 103.7 ​ Total operating revenues ​ $ (39.7) ​ $ (39.3) ​ $ (51.2) ​

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Stock-Based Compensation Plans
Stock-Based Compensation Disclosures (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions) Compensation cost ​ $ 86.7 ​ $ 78.7 ​ $ 77.5 ​ Related income tax benefit ​ ​ 17.1 ​ 16.8 ​ 16.7 ​ Capitalized as part of an asset ​ ​ 1.5 ​ 1.7 ​ 1.9 ​
Nonqualified Stock Options Status (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ average ​ ​ ​ ​ Number of options exercise price Intrinsic value ​ ​ (in millions) ​ ​ ​ ​ (in millions) Options outstanding as of January 1, 2020 5.3 ​ $ 48.42 ​ ​ ​ ​ Granted ​ 1.4 ​ ​ 51.73 ​ ​ ​ ​ Exercised ​ 0.1 ​ ​ 29.56 ​ ​ ​ ​ Canceled ​ 0.1 ​ ​ 51.81 ​ ​ ​ ​ Options outstanding as of December 31, 2020 ​ 6.5 ​ $ 49.52 ​ $ 27.5 ​ Options vested or expected to vest as of December 31, 2020 ​ 6.5 ​ $ 49.52 ​ $ 27.5 ​ Options exercisable as of December 31, 2020 ​ 4.2 ​ $ 47.38 ​ $ 27.5 ​
Nonqualified Stock Options Remaining Contractual Lives and Range of Exercise Prices (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ Number of options ​ average remaining Range of exercise prices outstanding contractual life ​ ​ (in millions) ​ ​ $27.46 - $41.13 ​ 1.6 ​ 3.3 ​ $41.14 - $51.53 ​ 1.0 ​ 3.7 ​ $51.54 - $52.41 ​ 1.3 ​ 9.1 ​ $52.42 - $62.75 ​ 1.2 ​ 8.1 ​ $62.76 - $63.98 ​ 1.4 ​ 6.7 ​ $27.46 - $63.98 ​ 6.5 ​ ​ ​
Nonqualified Stock Options Fair Value (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, Options 2020 2019 2018 Expected volatility ​ ​ 25.7 % ​ 23.3 % ​ 26.0 % Expected term (in years) ​ ​ 7.0 ​ ​ 7.0 ​ ​ 7.0 ​ Risk-free interest rate ​ ​ 1.3 % ​ 2.6 % ​ 2.8 % Expected dividend yield ​ ​ 4.33 % ​ 4.07 % ​ 3.19 % Weighted average estimated fair value ​ $ 9.64 ​ $ 10.00 ​ $ 14.85 ​
Nonvested Performance Share Awards Activity (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Weighted- ​ ​ performance ​ average grant-date ​ share awards fair value ​ ​ (in millions) ​ ​ ​ Nonvested performance share awards as of January 1, 2020 0.5 ​ $ 59.26 ​ Granted ​ 0.3 ​ ​ 51.73 ​ Vested ​ 0.1 ​ ​ 62.78 ​ Nonvested performance share awards as of December 31, 2020 ​ 0.7 ​ $ 55.28 ​
Nonvested Restricted Stock Units Activity (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Weighted- ​ ​ restricted ​ average grant-date ​ stock units fair value ​ ​ (in millions) ​ ​ ​ Nonvested restricted stock units as of January 1, 2020 2.6 ​ $ 59.15 ​ Granted ​ 1.1 ​ ​ 50.49 ​ Vested ​ 0.8 ​ ​ 62.32 ​ Canceled ​ 0.1 ​ ​ 55.68 ​ Nonvested restricted stock units as of December 31, 2020 ​ 2.8 ​ $ 54.86 ​

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Common Share
Earnings Per Common Share (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, ​ 2020 2019 2018 ​ ​ (in millions, except per share data) Net income ​ $ 1,428.5 ​ $ 1,444.1 ​ $ 1,553.7 ​ Subtract: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to noncontrolling interest ​ ​ 32.7 ​ 49.9 ​ 7.2 ​ Total ​ $ 1,395.8 ​ $ 1,394.2 ​ $ 1,546.5 ​ Weighted-average shares outstanding: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ ​ 274.7 ​ 278.6 ​ 285.8 ​ Dilutive effects: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options ​ ​ 0.3 ​ 0.9 ​ 1.0 ​ Restricted stock units ​ ​ 1.5 ​ 1.4 ​ 1.7 ​ Performance share awards ​ ​ 0.1 ​ 0.1 ​ 0.3 ​ Diluted ​ ​ 276.6 ​ 281.0 ​ 288.8 ​ Net income per common share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic ​ $ 5.08 ​ $ 5.00 ​ $ 5.41 ​ Diluted ​ $ 5.05 ​ $ 4.96 ​ $ 5.36 ​ ​

Quarterly Results of Operatio_2

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Results of Operations (Unaudited)
Quarterly Results of Operations (Table)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the three months ended , ​ December 31 September 30 June 30 March 31 ​ ​ (in millions, except per share data) 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 3,765.1 ​ $ 3,310.7 ​ $ 3,114.6 ​ $ 4,551.3 ​ Total expenses ​ ​ 3,173.5 ​ 3,035.6 ​ 2,616.0 ​ 4,223.1 ​ Net income ​ ​ 491.5 ​ 235.9 ​ 416.1 ​ 285.0 ​ Net income attributable to PFG ​ ​ 472.6 ​ 236.0 ​ 398.3 ​ 288.9 ​ Basic earnings per common share ​ ​ 1.72 ​ 0.86 ​ 1.45 ​ 1.05 ​ Diluted earnings per common share ​ ​ 1.70 ​ 0.85 ​ 1.45 ​ 1.04 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 4,047.2 ​ $ 4,458.4 ​ $ 3,972.6 ​ $ 3,743.9 ​ Total expenses ​ ​ 3,675.9 ​ 4,112.7 ​ 3,522.3 ​ 3,217.9 ​ Net income ​ ​ 315.3 ​ 284.6 ​ 392.1 ​ 452.1 ​ Net income attributable to PFG ​ ​ 300.9 ​ 277.1 ​ 386.3 ​ 429.9 ​ Basic earnings per common share ​ ​ 1.08 ​ 0.99 ​ 1.38 ​ 1.54 ​ Diluted earnings per common share ​ ​ 1.07 ​ 0.98 ​ 1.37 ​ 1.53 ​

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Condensed Consolidating Financial Information
Condensed Consolidating Financial Information, Shelf Registration Guarantor (Table)	Condensed Consolidating Statements of Financial Position December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ $ 813.2 ​ $ — ​ $ 77,897.1 ​ $ — ​ $ 78,710.3 ​ Fixed maturities, trading ​ 178.8 ​ ​ — ​ ​ 353.3 ​ ​ — ​ ​ 532.1 ​ Equity securities ​ — ​ ​ 42.9 ​ ​ 1,970.5 ​ ​ — ​ ​ 2,013.4 ​ Mortgage loans ​ — ​ ​ — ​ ​ 17,343.0 ​ ​ — ​ ​ 17,343.0 ​ Real estate ​ — ​ ​ — ​ ​ 1,797.3 ​ ​ — ​ ​ 1,797.3 ​ Policy loans ​ — ​ ​ — ​ ​ 784.0 ​ ​ — ​ ​ 784.0 ​ Investment in unconsolidated entities ​ 19,714.3 ​ ​ 18,557.9 ​ ​ 615.9 ​ ​ (38,045.4) ​ ​ 842.7 ​ Other investments ​ 63.7 ​ ​ 156.3 ​ ​ 4,064.1 ​ ​ — ​ ​ 4,284.1 ​ Cash and cash equivalents ​ 302.4 ​ ​ 819.1 ​ ​ 2,740.7 ​ ​ (1,012.4) ​ ​ 2,849.8 ​ Accrued investment income ​ 2.3 ​ ​ 0.2 ​ ​ 708.1 ​ ​ — ​ ​ 710.6 ​ Premiums due and other receivables ​ — ​ ​ 88.8 ​ ​ 1,910.2 ​ ​ (275.2) ​ ​ 1,723.8 ​ Deferred acquisition costs ​ — ​ ​ — ​ ​ 3,409.7 ​ ​ — ​ ​ 3,409.7 ​ Property and equipment ​ — ​ ​ — ​ ​ 1,019.0 ​ ​ — ​ ​ 1,019.0 ​ Goodwill ​ — ​ ​ 618.5 ​ ​ 1,092.5 ​ ​ — ​ ​ 1,711.0 ​ Other intangibles ​ — ​ ​ 503.6 ​ ​ 1,219.4 ​ ​ — ​ ​ 1,723.0 ​ Separate account assets ​ — ​ ​ — ​ ​ 175,951.4 ​ ​ — ​ ​ 175,951.4 ​ Other assets ​ 408.1 ​ ​ 58.0 ​ ​ 1,362.7 ​ ​ (606.3) ​ ​ 1,222.5 ​ Total assets ​ $ 21,482.8 ​ $ 20,845.3 ​ $ 294,238.9 ​ $ (39,939.3) ​ $ 296,627.7 ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractholder funds ​ $ — ​ $ — ​ $ 43,237.7 ​ $ — ​ $ 43,237.7 ​ Future policy benefits and claims ​ — ​ ​ — ​ ​ 45,207.2 ​ ​ — ​ ​ 45,207.2 ​ Other policyholder funds ​ — ​ ​ — ​ ​ 1,059.4 ​ ​ — ​ ​ 1,059.4 ​ Short-term debt ​ — ​ ​ — ​ ​ 84.7 ​ ​ — ​ ​ 84.7 ​ Long-term debt ​ 4,223.3 ​ ​ 274.9 ​ ​ 55.9 ​ ​ (274.9) ​ ​ 4,279.2 ​ Income taxes currently payable ​ — ​ ​ — ​ ​ 79.7 ​ ​ (57.4) ​ ​ 22.3 ​ Deferred income taxes ​ — ​ ​ 31.3 ​ ​ 2,824.4 ​ ​ (524.9) ​ ​ 2,330.8 ​ Separate account liabilities ​ — ​ ​ — ​ ​ 175,951.4 ​ ​ — ​ ​ 175,951.4 ​ Other liabilities ​ 700.6 ​ ​ 973.2 ​ ​ 6,769.6 ​ ​ (861.3) ​ ​ 7,582.1 ​ Total liabilities ​ 4,923.9 ​ ​ 1,279.4 ​ ​ 275,270.0 ​ ​ (1,718.5) ​ ​ 279,754.8 ​ Redeemable noncontrolling interest ​ — ​ ​ — ​ ​ 255.6 ​ ​ — ​ ​ 255.6 ​ Stockholders' equity ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common stock ​ 4.8 ​ ​ — ​ ​ 5.5 ​ ​ (5.5) ​ ​ 4.8 ​ Additional paid-in capital ​ 10,321.6 ​ ​ 9,738.4 ​ ​ 12,357.7 ​ ​ (22,096.1) ​ ​ 10,321.6 ​ Retained earnings ​ 11,838.0 ​ ​ 6,980.7 ​ ​ 3,285.9 ​ ​ (10,266.6) ​ ​ 11,838.0 ​ Accumulated other comprehensive income ​ 2,383.1 ​ ​ 2,846.8 ​ ​ 3,005.8 ​ ​ (5,852.6) ​ ​ 2,383.1 ​ Treasury stock, at cost ​ (7,988.6) ​ ​ — ​ ​ — ​ ​ — ​ ​ (7,988.6) ​ Total stockholders' equity attributable to PFG ​ 16,558.9 ​ ​ 19,565.9 ​ ​ 18,654.9 ​ ​ (38,220.8) ​ ​ 16,558.9 ​ Noncontrolling interest ​ — ​ ​ — ​ ​ 58.4 ​ ​ — ​ ​ 58.4 ​ Total stockholders’ equity ​ 16,558.9 ​ ​ 19,565.9 ​ ​ 18,713.3 ​ ​ (38,220.8) ​ ​ 16,617.3 ​ Total liabilities and stockholders' equity ​ $ 21,482.8 ​ $ 20,845.3 ​ $ 294,238.9 ​ $ (39,939.3) ​ $ 296,627.7 ​ (1) PFG sponsors nonqualified benefit plans. Nonqualified benefit plan assets and liabilities held in Rabbi trusts were $801.7 million and $653.3 million, respectively. ​ ​ Condensed Consolidating Statements of Financial Position December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities, available-for-sale ​ $ 265.8 ​ $ — ​ $ 69,840.4 ​ $ — ​ $ 70,106.2 ​ Fixed maturities, trading ​ 268.2 ​ ​ — ​ ​ 407.7 ​ ​ — ​ ​ 675.9 ​ Equity securities ​ — ​ ​ 41.4 ​ ​ 1,838.0 ​ ​ — ​ ​ 1,879.4 ​ Mortgage loans ​ — ​ ​ — ​ ​ 16,486.9 ​ ​ — ​ ​ 16,486.9 ​ Real estate ​ — ​ ​ — ​ ​ 1,714.8 ​ ​ — ​ ​ 1,714.8 ​ Policy loans ​ — ​ ​ — ​ ​ 798.0 ​ ​ — ​ ​ 798.0 ​ Investment in unconsolidated entities ​ 17,539.6 ​ ​ 16,664.1 ​ ​ 649.4 ​ ​ (34,022.9) ​ ​ 830.2 ​ Other investments ​ 10.4 ​ ​ 251.9 ​ ​ 3,597.7 ​ ​ — ​ ​ 3,860.0 ​ Cash and cash equivalents ​ 394.9 ​ ​ 598.4 ​ ​ 2,656.2 ​ ​ (1,133.6) ​ ​ 2,515.9 ​ Accrued investment income ​ 1.6 ​ ​ 0.4 ​ ​ 684.6 ​ ​ — ​ ​ 686.6 ​ Premiums due and other receivables ​ — ​ ​ 100.0 ​ ​ 1,961.1 ​ ​ (320.8) ​ ​ 1,740.3 ​ Deferred acquisition costs ​ — ​ ​ — ​ ​ 3,521.3 ​ ​ — ​ ​ 3,521.3 ​ Property and equipment ​ — ​ ​ — ​ ​ 967.7 ​ ​ — ​ ​ 967.7 ​ Goodwill ​ — ​ ​ 618.5 ​ ​ 1,075.3 ​ ​ — ​ ​ 1,693.8 ​ Other intangibles ​ — ​ ​ 531.7 ​ ​ 1,255.0 ​ ​ — ​ ​ 1,786.7 ​ Separate account assets ​ — ​ ​ — ​ ​ 165,468.0 ​ ​ — ​ ​ 165,468.0 ​ Other assets ​ 383.2 ​ ​ 35.2 ​ ​ 1,509.5 ​ ​ (571.8) ​ ​ 1,356.1 ​ Total assets ​ $ 18,863.7 ​ $ 18,841.6 ​ $ 274,431.6 ​ $ (36,049.1) ​ $ 276,087.8 ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contractholder funds ​ $ — ​ $ — ​ $ 41,367.5 ​ $ — ​ $ 41,367.5 ​ Future policy benefits and claims ​ — ​ ​ — ​ ​ 40,838.2 ​ ​ — ​ ​ 40,838.2 ​ Other policyholder funds ​ — ​ ​ — ​ ​ 959.4 ​ ​ — ​ ​ 959.4 ​ Short-term debt ​ — ​ ​ — ​ ​ 93.4 ​ ​ — ​ ​ 93.4 ​ Long-term debt ​ 3,625.5 ​ ​ 320.7 ​ ​ 108.7 ​ ​ (320.8) ​ ​ 3,734.1 ​ Income taxes currently payable ​ — ​ ​ — ​ ​ 66.4 ​ ​ (50.2) ​ ​ 16.2 ​ Deferred income taxes ​ — ​ ​ 5.9 ​ ​ 2,285.8 ​ ​ (495.1) ​ ​ 1,796.6 ​ Separate account liabilities ​ — ​ ​ — ​ ​ 165,468.0 ​ ​ — ​ ​ 165,468.0 ​ Other liabilities ​ 620.2 ​ ​ 1,113.6 ​ ​ 6,104.7 ​ ​ (974.8) ​ ​ 6,863.7 ​ Total liabilities ​ 4,245.7 ​ ​ 1,440.2 ​ ​ 257,292.1 ​ ​ (1,840.9) ​ ​ 261,137.1 ​ Redeemable noncontrolling interest ​ — ​ ​ — ​ ​ 264.9 ​ ​ — ​ ​ 264.9 ​ Stockholders' equity ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common stock ​ 4.8 ​ ​ — ​ ​ 11.0 ​ ​ (11.0) ​ ​ 4.8 ​ Additional paid-in capital ​ 10,182.6 ​ ​ 9,658.3 ​ ​ 12,157.9 ​ ​ (21,816.2) ​ ​ 10,182.6 ​ Retained earnings ​ 11,074.3 ​ ​ 6,263.5 ​ ​ 2,985.1 ​ ​ (9,248.6) ​ ​ 11,074.3 ​ Accumulated other comprehensive income ​ 1,037.9 ​ ​ 1,479.6 ​ ​ 1,654.8 ​ ​ (3,134.4) ​ ​ 1,037.9 ​ Treasury stock, at cost ​ (7,681.6) ​ ​ — ​ ​ (2.0) ​ ​ 2.0 ​ ​ (7,681.6) ​ Total stockholders' equity attributable to PFG ​ 14,618.0 ​ ​ 17,401.4 ​ ​ 16,806.8 ​ ​ (34,208.2) ​ ​ 14,618.0 ​ Noncontrolling interest ​ — ​ ​ — ​ ​ 67.8 ​ ​ — ​ ​ 67.8 ​ Total stockholders’ equity ​ 14,618.0 ​ ​ 17,401.4 ​ ​ 16,874.6 ​ ​ (34,208.2) ​ ​ 14,685.8 ​ Total liabilities and stockholders' equity ​ $ 18,863.7 ​ $ 18,841.6 ​ $ 274,431.6 ​ $ (36,049.1) ​ $ 276,087.8 ​ (1) PFG sponsors nonqualified benefit plans. Nonqualified benefit plan assets and liabilities held in Rabbi trusts were $731.9 million and $593.7 million, respectively. ​ Condensed Consolidating Statements of Operations For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ — ​ $ — ​ $ 6,037.4 ​ $ — ​ $ 6,037.4 ​ Fees and other revenues ​ — ​ ​ 341.3 ​ ​ 4,182.9 ​ ​ (13.1) ​ ​ 4,511.1 ​ Net investment income (loss) ​ 13.3 ​ ​ (1.4) ​ ​ 3,867.1 ​ ​ 11.6 ​ ​ 3,890.6 ​ Net realized capital gains ​ 7.0 ​ ​ 32.8 ​ ​ 262.9 ​ ​ (0.1) ​ ​ 302.6 ​ Total revenues ​ 20.3 ​ ​ 372.7 ​ ​ 14,350.3 ​ ​ (1.6) ​ ​ 14,741.7 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ — ​ ​ — ​ ​ 8,281.5 ​ ​ — ​ ​ 8,281.5 ​ Dividends to policyholders ​ — ​ ​ — ​ ​ 120.2 ​ ​ — ​ ​ 120.2 ​ Operating expenses ​ 200.0 ​ ​ 548.7 ​ ​ 3,909.6 ​ ​ (11.8) ​ ​ 4,646.5 ​ Total expenses ​ 200.0 ​ ​ 548.7 ​ ​ 12,311.3 ​ ​ (11.8) ​ ​ 13,048.2 ​ Income (loss) before income taxes ​ (179.7) ​ ​ (176.0) ​ ​ 2,039.0 ​ ​ 10.2 ​ ​ 1,693.5 ​ Income taxes (benefits) ​ (46.1) ​ ​ (45.8) ​ ​ 356.9 ​ ​ — ​ ​ 265.0 ​ Equity in the net income of subsidiaries ​ 1,529.4 ​ ​ 1,649.4 ​ ​ — ​ ​ (3,178.8) ​ ​ — ​ Net income ​ 1,395.8 ​ ​ 1,519.2 ​ ​ 1,682.1 ​ ​ (3,168.6) ​ ​ 1,428.5 ​ Net income attributable to noncontrolling interest ​ — ​ ​ — ​ ​ 32.7 ​ ​ — ​ ​ 32.7 ​ Net income attributable to PFG ​ $ 1,395.8 ​ $ 1,519.2 ​ $ 1,649.4 ​ $ (3,168.6) ​ $ 1,395.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,395.8 ​ $ 1,519.2 ​ $ 1,682.1 ​ $ (3,168.6) ​ $ 1,428.5 ​ Other comprehensive income ​ 1,206.5 ​ ​ 1,228.6 ​ ​ 1,352.7 ​ ​ (2,440.8) ​ ​ 1,347.0 ​ Comprehensive income ​ $ 2,602.3 ​ $ 2,747.8 ​ $ 3,034.8 ​ $ (5,609.4) ​ $ 2,775.5 ​ ​ ​ Condensed Consolidating Statements of Operations For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ — ​ $ — ​ $ 7,866.6 ​ $ — ​ $ 7,866.6 ​ Fees and other revenues ​ — ​ ​ 205.9 ​ ​ 4,215.5 ​ ​ (11.5) ​ ​ 4,409.9 ​ Net investment income (loss) ​ 19.4 ​ ​ (6.5) ​ ​ 3,975.1 ​ ​ 10.4 ​ ​ 3,998.4 ​ Net realized capital gains (losses), excluding impairment losses on available-for-sale securities ​ 12.3 ​ ​ 17.5 ​ ​ (38.9) ​ ​ (0.2) ​ ​ (9.3) ​ Net other-than-temporary impairment losses on available-for-sale securities ​ — ​ ​ — ​ ​ (38.3) ​ ​ — ​ ​ (38.3) ​ Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income ​ — ​ ​ — ​ ​ (5.2) ​ ​ — ​ ​ (5.2) ​ Net impairment losses on available-for-sale securities ​ — ​ ​ — ​ ​ (43.5) ​ ​ — ​ ​ (43.5) ​ Net realized capital gains (losses) ​ 12.3 ​ ​ 17.5 ​ ​ (82.4) ​ ​ (0.2) ​ ​ (52.8) ​ Total revenues ​ 31.7 ​ ​ 216.9 ​ ​ 15,974.8 ​ ​ (1.3) ​ ​ 16,222.1 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ — ​ ​ — ​ ​ 9,905.8 ​ ​ — ​ ​ 9,905.8 ​ Dividends to policyholders ​ — ​ ​ — ​ ​ 119.1 ​ ​ — ​ ​ 119.1 ​ Operating expenses ​ 210.9 ​ ​ 368.2 ​ ​ 3,935.1 ​ ​ (10.3) ​ ​ 4,503.9 ​ Total expenses ​ 210.9 ​ ​ 368.2 ​ ​ 13,960.0 ​ ​ (10.3) ​ ​ 14,528.8 ​ Income (loss) before income taxes ​ (179.2) ​ ​ (151.3) ​ ​ 2,014.8 ​ ​ 9.0 ​ ​ 1,693.3 ​ Income taxes (benefits) ​ (44.2) ​ ​ (11.8) ​ ​ 305.2 ​ ​ — ​ ​ 249.2 ​ Equity in the net income of subsidiaries ​ 1,529.2 ​ ​ 1,659.7 ​ ​ — ​ ​ (3,188.9) ​ ​ — ​ Net income ​ 1,394.2 ​ ​ 1,520.2 ​ ​ 1,709.6 ​ ​ (3,179.9) ​ ​ 1,444.1 ​ Net income attributable to noncontrolling interest ​ — ​ ​ — ​ ​ 49.9 ​ ​ — ​ ​ 49.9 ​ Net income attributable to PFG ​ $ 1,394.2 ​ $ 1,520.2 ​ $ 1,659.7 ​ $ (3,179.9) ​ $ 1,394.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,394.2 ​ $ 1,520.2 ​ $ 1,709.6 ​ $ (3,179.9) ​ $ 1,444.1 ​ Other comprehensive income ​ 2,570.9 ​ ​ 2,530.9 ​ ​ 2,562.2 ​ ​ (5,057.3) ​ ​ 2,606.7 ​ Comprehensive income ​ $ 3,965.1 ​ $ 4,051.1 ​ $ 4,271.8 ​ $ (8,237.2) ​ $ 4,050.8 ​ ​ ​ Condensed Consolidating Statements of Operations For the year ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Premiums and other considerations ​ $ — ​ $ — ​ $ 6,409.6 ​ $ — ​ $ 6,409.6 ​ Fees and other revenues ​ — ​ 2.7 ​ 4,286.4 ​ (15.3) ​ 4,273.8 ​ Net investment income (loss) ​ 25.8 ​ (6.7) ​ 3,598.0 ​ 12.1 ​ 3,629.2 ​ Net realized capital losses, excluding impairment losses on available-for-sale securities ​ (8.2) ​ (3.5) ​ (34.6) ​ — ​ (46.3) ​ Net other-than-temporary impairment recoveries on available-for-sale securities ​ — ​ — ​ 10.6 ​ — ​ 10.6 ​ Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income ​ — ​ — ​ (39.7) ​ — ​ (39.7) ​ Net impairment losses on available-for-sale securities ​ — ​ — ​ (29.1) ​ — ​ (29.1) ​ Net realized capital losses ​ (8.2) ​ (3.5) ​ (63.7) ​ — ​ (75.4) ​ Total revenues ​ 17.6 ​ (7.5) ​ 14,230.3 ​ (3.2) ​ 14,237.2 ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefits, claims and settlement expenses ​ — ​ — ​ 8,192.5 ​ — ​ 8,192.5 ​ Dividends to policyholders ​ — ​ — ​ 123.6 ​ — ​ 123.6 ​ Operating expenses ​ 191.9 ​ 29.1 ​ 3,929.5 ​ (13.8) ​ 4,136.7 ​ Total expenses ​ 191.9 ​ 29.1 ​ 12,245.6 ​ (13.8) ​ 12,452.8 ​ Income (loss) before income taxes ​ (174.3) ​ (36.6) ​ 1,984.7 ​ 10.6 ​ 1,784.4 ​ Income taxes (benefits) ​ (62.5) ​ 0.2 ​ 293.0 ​ — ​ 230.7 ​ Equity in the net income of subsidiaries ​ 1,658.3 ​ 1,684.5 ​ — ​ (3,342.8) ​ — ​ Net income ​ ​ 1,546.5 ​ ​ 1,647.7 ​ ​ 1,691.7 ​ (3,332.2) ​ 1,553.7 ​ Net income attributable to noncontrolling interest ​ — ​ — ​ 7.2 ​ — ​ 7.2 ​ Net income attributable to PFG ​ $ 1,546.5 ​ $ 1,647.7 ​ $ 1,684.5 ​ $ (3,332.2) ​ $ 1,546.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 1,546.5 ​ $ 1,647.7 ​ $ 1,691.7 ​ $ (3,332.2) ​ $ 1,553.7 ​ Other comprehensive loss ​ (1,824.5) ​ ​ (1,839.1) ​ ​ (1,856.4) ​ ​ 3,684.3 ​ ​ (1,835.7) ​ Comprehensive loss ​ $ (278.0) ​ $ (191.4) ​ $ (164.7) ​ $ 352.1 ​ $ (282.0) ​ ​ ​ Condensed Consolidating Statements of Cash Flows For the year ended December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) operating activities ​ $ (15.2) ​ $ 1,490.5 ​ $ 4,014.8 ​ $ (1,751.5) ​ $ 3,738.6 ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ ​ (736.5) ​ ​ — ​ ​ (14,976.9) ​ ​ — ​ ​ (15,713.4) ​ Sales ​ ​ — ​ ​ — ​ ​ 3,043.9 ​ ​ — ​ ​ 3,043.9 ​ Maturities ​ ​ 193.7 ​ ​ — ​ ​ 8,625.8 ​ ​ — ​ ​ 8,819.5 ​ Mortgage loans acquired or originated ​ ​ — ​ ​ — ​ ​ (3,249.5) ​ ​ — ​ ​ (3,249.5) ​ Mortgage loans sold or repaid ​ ​ — ​ ​ — ​ ​ 2,477.2 ​ ​ — ​ ​ 2,477.2 ​ Real estate acquired ​ ​ — ​ ​ — ​ ​ (230.6) ​ ​ — ​ ​ (230.6) ​ Real estate sold ​ ​ — ​ ​ — ​ ​ 2.3 ​ ​ — ​ ​ 2.3 ​ Net purchases of property and equipment ​ ​ (0.1) ​ ​ (3.5) ​ ​ (105.2) ​ ​ — ​ ​ (108.8) ​ Dividends and returns of capital received from unconsolidated entities ​ ​ 799.1 ​ ​ 1,189.2 ​ ​ — ​ ​ (1,988.3) ​ ​ — ​ Net change in other investments ​ ​ (50.0) ​ ​ (1,610.4) ​ ​ (232.7) ​ ​ 1,826.7 ​ ​ (66.4) ​ Net cash provided by (used in) investing activities ​ ​ 206.2 ​ ​ (424.7) ​ ​ (4,645.7) ​ ​ (161.6) ​ ​ (5,025.8) ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ ​ 42.8 ​ ​ — ​ ​ — ​ ​ — ​ ​ 42.8 ​ Acquisition of treasury stock ​ ​ (307.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ (307.0) ​ Payments for financing element derivatives ​ ​ — ​ ​ — ​ ​ (30.9) ​ ​ — ​ ​ (30.9) ​ Purchase of subsidiary shares from noncontrolling interest ​ ​ — ​ ​ — ​ ​ (1.4) ​ ​ — ​ ​ (1.4) ​ Dividends to common stockholders ​ ​ (614.5) ​ ​ — ​ ​ — ​ ​ — ​ ​ (614.5) ​ Issuance of long-term debt ​ ​ 595.2 ​ ​ 8.5 ​ ​ 13.7 ​ ​ (8.5) ​ ​ 608.9 ​ Principal repayments of long-term debt ​ ​ — ​ ​ (54.5) ​ ​ (65.8) ​ ​ 54.5 ​ ​ (65.8) ​ Net repayments of short-term borrowings ​ ​ — ​ ​ — ​ ​ (12.6) ​ ​ — ​ ​ (12.6) ​ Dividends and capital paid to parent ​ ​ — ​ ​ (799.1) ​ ​ (1,189.2) ​ ​ 1,988.3 ​ ​ — ​ Investment contract deposits ​ ​ — ​ ​ — ​ ​ 10,284.4 ​ ​ — ​ ​ 10,284.4 ​ Investment contract withdrawals ​ ​ — ​ ​ — ​ ​ (8,852.7) ​ ​ — ​ ​ (8,852.7) ​ Net increase in banking operation deposits ​ ​ — ​ ​ — ​ ​ 569.7 ​ ​ — ​ ​ 569.7 ​ Other ​ ​ — ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ 0.2 ​ Net cash provided by (used in) financing activities ​ ​ (283.5) ​ ​ (845.1) ​ ​ 715.4 ​ ​ 2,034.3 ​ ​ 1,621.1 ​ Net increase (decrease) in cash and cash equivalents ​ ​ (92.5) ​ ​ 220.7 ​ ​ 84.5 ​ ​ 121.2 ​ ​ 333.9 ​ Cash and cash equivalents at beginning of period ​ 394.9 ​ ​ 598.4 ​ ​ 2,656.2 ​ ​ (1,133.6) ​ ​ 2,515.9 ​ Cash and cash equivalents at end of period ​ $ 302.4 ​ $ 819.1 ​ $ 2,740.7 ​ $ (1,012.4) ​ $ 2,849.8 ​ ​ ​ Condensed Consolidating Statements of Cash Flows For the year ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined ​ Eliminations ​ consolidated ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) operating activities ​ $ 7.1 ​ $ (54.7) ​ $ 5,760.7 ​ $ (219.9) ​ $ 5,493.2 ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ ​ (251.5) ​ ​ (0.2) ​ ​ (13,885.4) ​ ​ — ​ ​ (14,137.1) ​ Sales ​ ​ — ​ ​ 0.2 ​ ​ 2,397.2 ​ ​ — ​ ​ 2,397.4 ​ Maturities ​ ​ 200.0 ​ ​ — ​ ​ 6,864.2 ​ ​ — ​ ​ 7,064.2 ​ Mortgage loans acquired or originated ​ ​ — ​ ​ — ​ ​ (3,487.7) ​ ​ — ​ ​ (3,487.7) ​ Mortgage loans sold or repaid ​ ​ — ​ ​ — ​ ​ 2,335.9 ​ ​ — ​ ​ 2,335.9 ​ Real estate acquired ​ ​ — ​ ​ — ​ ​ (127.5) ​ ​ — ​ ​ (127.5) ​ Real estate sold ​ ​ — ​ ​ — ​ ​ 96.3 ​ ​ — ​ ​ 96.3 ​ Net purchases of property and equipment ​ ​ (0.1) ​ ​ (2.0) ​ ​ (130.3) ​ ​ — ​ ​ (132.4) ​ Purchase of business or interests in subsidiaries, net of cash acquired ​ ​ — ​ ​ (1,209.6) ​ ​ 1.1 ​ ​ — ​ ​ (1,208.5) ​ Dividends and returns of capital received from unconsolidated entities ​ ​ 494.2 ​ ​ 2,118.7 ​ ​ — ​ ​ (2,612.9) ​ ​ — ​ Net change in other investments ​ ​ (34.0) ​ ​ (362.9) ​ ​ (235.8) ​ ​ 143.6 ​ ​ (489.1) ​ Net cash provided by (used in) investing activities ​ ​ 408.6 ​ ​ 544.2 ​ ​ (6,172.0) ​ ​ (2,469.3) ​ ​ (7,688.5) ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ ​ 37.7 ​ ​ — ​ ​ — ​ ​ — ​ ​ 37.7 ​ Acquisition of treasury stock ​ ​ (281.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ (281.0) ​ Payments for financing element derivatives ​ ​ — ​ ​ — ​ ​ (26.9) ​ ​ — ​ ​ (26.9) ​ Purchase of subsidiary shares from noncontrolling interest ​ ​ — ​ ​ — ​ ​ (1.7) ​ ​ — ​ ​ (1.7) ​ Dividends to common stockholders ​ ​ (606.0) ​ ​ — ​ ​ — ​ ​ — ​ ​ (606.0) ​ Issuance of long-term debt ​ ​ 493.6 ​ ​ 10.0 ​ ​ 11.3 ​ ​ (10.0) ​ ​ 504.9 ​ Principal repayments of long-term debt ​ ​ — ​ ​ (55.9) ​ ​ (32.2) ​ ​ 55.9 ​ ​ (32.2) ​ Net proceeds from short-term borrowings ​ ​ — ​ ​ — ​ ​ 57.5 ​ ​ — ​ ​ 57.5 ​ Dividends and capital paid to parent ​ ​ — ​ ​ (494.2) ​ ​ (2,118.7) ​ ​ 2,612.9 ​ ​ — ​ Investment contract deposits ​ ​ — ​ ​ — ​ ​ 9,200.0 ​ ​ — ​ ​ 9,200.0 ​ Investment contract withdrawals ​ ​ — ​ ​ — ​ ​ (7,747.7) ​ ​ — ​ ​ (7,747.7) ​ Net increase in banking operation deposits ​ ​ — ​ ​ — ​ ​ 623.4 ​ ​ — ​ ​ 623.4 ​ Other ​ ​ — ​ ​ — ​ ​ 5.7 ​ ​ — ​ ​ 5.7 ​ Net cash provided by (used in) financing activities ​ ​ (355.7) ​ ​ (540.1) ​ ​ (29.3) ​ ​ 2,658.8 ​ ​ 1,733.7 ​ Net increase (decrease) in cash and cash equivalents ​ ​ 60.0 ​ ​ (50.6) ​ ​ (440.6) ​ ​ (30.4) ​ ​ (461.6) ​ Cash and cash equivalents at beginning of period ​ 334.9 ​ 649.0 ​ 3,096.8 ​ (1,103.2) ​ 2,977.5 ​ Cash and cash equivalents at end of period ​ $ 394.9 ​ $ 598.4 ​ $ 2,656.2 ​ $ (1,133.6) ​ $ 2,515.9 ​ ​ ​ Condensed Consolidating Statements of Cash Flows For the year ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Principal Life ​ ​ ​ ​ ​ ​ Principal ​ Principal ​ Insurance Company ​ ​ ​ ​ Principal ​ ​ Financial ​ Financial ​ and other ​ ​ ​ ​ Financial ​ ​ Group, Inc. ​ Services, Inc. ​ subsidiaries ​ ​ ​ ​ Group, Inc. ​ ​ ​ parent only ​ only ​ combined (1) ​ Eliminations ​ consolidated ​ ​ (in millions) Operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) operating activities ​ $ (132.4) ​ $ 696.3 ​ $ 5,030.9 ​ $ (438.3) ​ $ 5,156.5 ​ Investing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturities available-for-sale and equity securities with intent to hold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Purchases ​ (210.9) ​ — ​ (13,698.9) ​ — ​ (13,909.8) ​ Sales ​ — ​ — ​ 3,813.1 ​ — ​ 3,813.1 ​ Maturities ​ 2.3 ​ — ​ 6,215.3 ​ — ​ 6,217.6 ​ Mortgage loans acquired or originated ​ — ​ — ​ (3,447.5) ​ — ​ (3,447.5) ​ Mortgage loans sold or repaid ​ — ​ — ​ 2,228.4 ​ — ​ 2,228.4 ​ Real estate acquired ​ — ​ — ​ (88.1) ​ — ​ (88.1) ​ Real estate sold ​ ​ — ​ ​ — ​ ​ 63.5 ​ ​ — ​ ​ 63.5 ​ Net purchases of property and equipment ​ (0.1) ​ — ​ (92.2) ​ — ​ (92.3) ​ Purchase of business or interests in subsidiaries, net of cash acquired ​ ​ — ​ ​ — ​ ​ (184.7) ​ ​ — ​ ​ (184.7) ​ Dividends and returns of capital received from unconsolidated entities ​ 1,041.6 ​ 589.1 ​ — ​ (1,630.7) ​ — ​ Net change in other investments ​ (2.2) ​ (166.2) ​ (413.9) ​ 279.6 ​ (302.7) ​ Net cash provided by (used in) investing activities ​ 830.7 ​ 422.9 ​ (5,605.0) ​ (1,351.1) ​ (5,702.5) ​ Financing activities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Issuance of common stock ​ 64.0 ​ — ​ — ​ — ​ 64.0 ​ Acquisition of treasury stock ​ (671.6) ​ — ​ — ​ — ​ (671.6) ​ Payments for financing element derivatives ​ — ​ — ​ (65.9) ​ — ​ (65.9) ​ Purchase of subsidiary shares from noncontrolling interest ​ — ​ — ​ (31.1) ​ — ​ (31.1) ​ Dividends to common stockholders ​ (598.6) ​ — ​ — ​ — ​ (598.6) ​ Issuance of long-term debt ​ — ​ 11.1 ​ 80.8 ​ (11.1) ​ 80.8 ​ Principal repayments of long-term debt ​ — ​ (57.1) ​ (1.3) ​ 57.1 ​ (1.3) ​ Net proceeds from short-term borrowings ​ — ​ — ​ 8.5 ​ — ​ 8.5 ​ Dividends and capital paid to parent ​ — ​ (1,041.6) ​ (589.1) ​ 1,630.7 ​ — ​ Investment contract deposits ​ — ​ — ​ 8,308.8 ​ — ​ 8,308.8 ​ Investment contract withdrawals ​ — ​ — ​ (6,589.6) ​ — ​ (6,589.6) ​ Net increase in banking operation deposits ​ — ​ — ​ 553.0 ​ — ​ 553.0 ​ Other ​ — ​ — ​ (4.3) ​ — ​ (4.3) ​ Net cash provided by (used in) financing activities ​ (1,206.2) ​ (1,087.6) ​ 1,669.8 ​ 1,676.7 ​ 1,052.7 ​ Net increase (decrease) in cash and cash equivalents ​ (507.9) ​ 31.6 ​ 1,095.7 ​ (112.7) ​ 506.7 ​ Cash and cash equivalents at beginning of period ​ 842.8 ​ 617.4 ​ 2,001.1 ​ (990.5) ​ 2,470.8 ​ Cash and cash equivalents at end of period ​ $ 334.9 ​ $ 649.0 ​ $ 3,096.8 ​ $ (1,103.2) ​ $ 2,977.5 ​

Nature of Operations and Sign_4

Nature of Operations and Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Recent Accounting Pronouncements
Stockholders' Equity	$ 12,921.9	$ 16,617.3	$ 14,685.8	$ 11,456
Accumulated other comprehensive income (loss)
Recent Accounting Pronouncements
Stockholders' Equity	165.5	2,383.1	1,037.9	(1,565.1)
Retained earnings (accumulated deficit)
Recent Accounting Pronouncements
Stockholders' Equity	9,482.9	$ 11,838	11,074.3	10,290.2
ASU 2018-02 - Reclassification of certain tax effects | Accumulated other comprehensive income (loss) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	77.6
ASU 2018-02 - Reclassification of certain tax effects | Retained earnings (accumulated deficit) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(77.6)
ASU 2014-09 - Revenue recognition | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(39.7)
ASU 2014-09 - Revenue recognition | Accumulated other comprehensive income (loss) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	25.6
ASU 2014-09 - Revenue recognition | Retained earnings (accumulated deficit) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(65)
ASU 2016-16 - Intra-entity asset transfer taxes | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	8.7
Cumulative effect adjustment, decrease to other assets	21.1
Cumulative effect adjustment, decrease to deferred income taxes	29.8
ASU 2016-16 - Intra-entity asset transfer taxes | Retained earnings (accumulated deficit) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	8.7
ASU 2016-01 - Equity investments | Accumulated other comprehensive income (loss) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(1)
ASU 2016-01 - Equity investments | Retained earnings (accumulated deficit) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	$ 1
ASU 2016-02 - Leases | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity				4
ASU 2016-02 - Leases | Retained earnings (accumulated deficit) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity				$ 4
ASU 2016-13 - CECL | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity			(8.4)
ASU 2016-13 - CECL | Retained earnings (accumulated deficit) | Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity			$ (8.4)

Nature of Operations and Sign_5

Nature of Operations and Significant Accounting Policies - Cash and Cash Equivalents, Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash and Cash Equivalents
Maximum maturity period when purchased for investments to be included in cash and cash equivalents	3 months
Investments
Real estate held for sale	$ 2	$ 169.8

Nature of Operations and Sign_6

Nature of Operations and Significant Accounting Policies - Contractholder and Policyholder Liabilities (Details) - Individual Life insurance	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Contractholder and Policyholder Liabilities
Participating business as a percentage of life insurance in force (as a percent)	5.00%	6.00%	7.00%
Participating business as a percentage of life insurance policies in force (as a percent)	20.00%	23.00%	26.00%
Participating business as a percentage of life insurance premiums (as a percent)	24.00%	21.00%	24.00%

Nature of Operations and Sign_7

Nature of Operations and Significant Accounting Policies - Other Various Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)Counterparty	Dec. 31, 2019USD ($)Counterparty	Dec. 31, 2018USD ($)
Long-Term Debt
Minimum maturity period at date of issuance for debt to be classified as long-term	1 year
Reinsurance
Net ceded reinsurance recoverables related to claims received	$ 1,095.3	$ 997.8
Amount of net ceded reinsurance recoverables related to claims received with five largest ceded reinsurers	$ 506.3	$ 457.2
Percentage of net ceded reinsurance recoverables related to claims received with five largest ceded reinsurers (as a percent)	97.00%	98.00%
Number of largest ceded reinsurers | Counterparty	5	5
Premiums and other considerations:
Premiums and other considerations, Direct	$ 6,645.4	$ 8,428.1	$ 6,928.3
Premiums and other considerations, Assumed	1.7	1.6	1.7
Premiums and other considerations, Ceded	(609.7)	(563.1)	(520.4)
Premiums and other considerations	6,037.4	7,866.6	6,409.6
Benefits, claims and settlement expenses:
Benefits, claims and settlement expenses, Direct	8,788.3	10,463.6	8,667.7
Benefits, claims and settlement expenses, Assumed	21.8	23.1	24.9
Benefits, claims and settlement expenses, Ceded	(528.6)	(580.9)	(500.1)
Benefits, claims and settlement expenses	8,281.5	9,905.8	$ 8,192.5
Separate Accounts
Separate account that primarily includes shares of Principal Financial Group, Inc. stock that were allocated and issued to eligible participants of qualified employee benefit plans as part of the 2001 demutualization	$ 80.4	$ 100.4

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Changes in Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Changes in Goodwill
Beginning balance, Goodwill	$ 1,693.8	$ 1,100
Goodwill from acquisitions		623.9
Foreign currency, Goodwill	17.2	(30.1)
Ending balance, Goodwill	1,711	1,693.8
Retirement and Income Solutions
Changes in Goodwill
Beginning balance, Goodwill	675.9	57.4
Goodwill from acquisitions		618.5
Ending balance, Goodwill	675.9	675.9
Principal Global Investors
Changes in Goodwill
Beginning balance, Goodwill	317.5	307.3
Goodwill from acquisitions		6.5
Foreign currency, Goodwill	3.4	1.5
Other, Goodwill		2.2
Ending balance, Goodwill	320.9	317.5
Principal International
Changes in Goodwill
Beginning balance, Goodwill	642.8	676.6
Foreign currency, Goodwill	13.8	(31.6)
Other, Goodwill		(2.2)
Ending balance, Goodwill	656.6	642.8
U.S. Insurance Solutions
Changes in Goodwill
Beginning balance, Goodwill	56.6	56.6
Ending balance, Goodwill	56.6	56.6
Corporate
Changes in Goodwill
Beginning balance, Goodwill	1	2.1
Goodwill from acquisitions		(1.1)
Ending balance, Goodwill	$ 1	$ 1

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Goodwill Acquired (Details) - USD ($) $ in Millions	Jul. 01, 2019	Dec. 31, 2019
Goodwill and Other Intangible Assets
Goodwill from acquisitions		$ 623.9
Institutional Retirement & Trust business of Wells Fargo Bank
Goodwill and Other Intangible Assets
Purchase price of acquired business in the form of cash to be paid at the closing	$ 1,200
Goodwill from acquisitions	618.5
Customer relationships | Institutional Retirement & Trust business of Wells Fargo Bank
Goodwill and Other Intangible Assets
Finite lived intangible assets acquired	$ 510.3
Finite lived intangible asset, useful life	23 years
Technology | Institutional Retirement & Trust business of Wells Fargo Bank
Goodwill and Other Intangible Assets
Finite lived intangible assets acquired	$ 35.4
Finite lived intangible asset, useful life	6 years

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite Lived Intangible Asset Disclosures
Weighted average remaining expected life of finite lived intangible assets	17 years
Gross carrying amount	$ 1,338.2	$ 1,346.3
Accumulated amortization	405.6	343.2
Net carrying amount	932.6	1,003.1
Amortization expense for intangible assets with finite useful lives	73.5	$ 62.8	$ 53.9
Estimated amortization expense for the next five years
Year 1: Finite lived intangible assets amortization	75.1
Year 2: Finite lived intangible assets amortization	73.9
Year 3: Finite lived intangible assets amortization	71.2
Year 4: Finite lived intangible assets amortization	70
Year 5: Finite lived intangible assets amortization	68.2
Other finite lived intangible assets
Finite Lived Intangible Asset Disclosures
Amortization expense for intangible assets with finite useful lives	$ 18.7

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Indefinite-Lived Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Indefinite Lived Intangible Assets
Net carrying amount of unamortized indefinite lived intangible assets	$ 790.4	$ 783.6
WM Advisors, Inc.
Indefinite Lived Intangible Assets
Net carrying amount of unamortized indefinite lived intangible assets	$ 608	$ 608

Variable Interest Entities - Co

Variable Interest Entities - Consolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Carrying amounts of consolidated VIE assets and liabilities
Total assets	$ 296,627.7	$ 276,087.8
Total liabilities	279,754.8	261,137.1
Redeemable noncontrolling interest	255.6	264.9	$ 391.2	$ 101.3
Aggregate consolidated variable interest entities
Carrying amounts of consolidated VIE assets and liabilities
Total assets	43,233.5	40,802.1
Total liabilities	41,552.4	39,713.7
Redeemable noncontrolling interest	226.8	215.4
Grantor trust
Carrying amounts of consolidated VIE assets and liabilities
Total assets		99.9
Total liabilities		98.6
Mandatory retirement savings funds
Carrying amounts of consolidated VIE assets and liabilities
Total assets	41,995.2	39,891.1
Total liabilities	41,527.9	39,524.9
Real estate VIE
Carrying amounts of consolidated VIE assets and liabilities
Total assets	499	479.7
Total liabilities	21.3	88
Sponsored investment funds
Carrying amounts of consolidated VIE assets and liabilities
Total assets	419.5	331.4
Total liabilities	3.2	2.2
Redeemable noncontrolling interest	226.8	$ 215.4
Residential mortgage loans
Carrying amounts of consolidated VIE assets and liabilities
Total assets	$ 319.8

Variable Interest Entities - Un

Variable Interest Entities - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	$ 296,627.7	$ 276,087.8
Money Market Funds
Total assets of unconsolidated money market mutual funds	4,400	4,000
Corporate debt securities | Available-for-sale
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	285.7	225.7
Corporate debt securities | Available-for-sale | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	296.9	238.2
Residential mortgage-backed pass-through securities | Available-for-sale
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	2,857.6	2,913.9
Residential mortgage-backed pass-through securities | Available-for-sale | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	2,986.8	2,982.4
Residential mortgage-backed pass-through securities | Trading
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	190.5	282.3
Residential mortgage-backed pass-through securities | Trading | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	190.5	282.3
Commercial mortgage-backed securities | Available-for-sale
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	4,741.2	4,746.6
Commercial mortgage-backed securities | Available-for-sale | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	4,942.3	4,850.2
Commercial mortgage-backed securities | Trading
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	27.1	28.2
Commercial mortgage-backed securities | Trading | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	27.1	28.2
Collateralized debt obligations | Available-for-sale
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	4,045.9	3,226.7
Collateralized debt obligations | Available-for-sale | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	4,027.5	3,215.3
Collateralized debt obligations | Trading
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	20.6	20.9
Collateralized debt obligations | Trading | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	20.6	20.9
Other debt obligations | Available-for-sale
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	6,832.6	8,076.4
Other debt obligations | Available-for-sale | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	7,045.9	8,191.1
Other debt obligations | Trading
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	9.4	13.2
Other debt obligations | Trading | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	9.4	13.2
Equity securities
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	121.7	123.2
Equity securities | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	121.7	123.2
Other investments: Other limited partnership and fund interests
Unconsolidated Variable Interest Entity disclosures
Maximum exposure to loss	1,739	1,467
Fully secured debt of international real estate funds with recourse to the investment manager, included in maximum loss exposure	141.2	129.1
Other investments: Other limited partnership and fund interests | Variable Interest Entity
Unconsolidated Variable Interest Entity disclosures
Asset carrying value	$ 999.1	$ 911.9

Investments - Fixed Maturities

Investments - Fixed Maturities and Equity Securities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale securities
Amortized cost, fixed maturities	$ 70,546.8	$ 65,302.5
Gross unrealized gains, fixed maturities	8,380	4,927.7
Gross unrealized losses, fixed maturities	209.1	124
Allowance, fixed maturities	7.4
Fair value, fixed maturities	78,710.3	70,106.2
Other-than-temporary impairments in AOCI		48.4
Accrued interest receivable	552.5
Net unrealized gains (losses) on impaired fixed maturities, available-for-sale related to changes in fair value subsequent to the impairment date		62.3
U.S. government and agencies
Available-for-sale securities
Amortized cost, fixed maturities	1,893.1	1,627
Gross unrealized gains, fixed maturities	228.9	100.2
Gross unrealized losses, fixed maturities	10.5	3
Fair value, fixed maturities	2,111.5	1,724.2
Non-U.S. governments
Available-for-sale securities
Amortized cost, fixed maturities	881.6	852.3
Gross unrealized gains, fixed maturities	192.1	144.1
Gross unrealized losses, fixed maturities		0.2
Fair value, fixed maturities	1,073.7	996.2
States and political subdivisions
Available-for-sale securities
Amortized cost, fixed maturities	8,004.9	6,857.1
Gross unrealized gains, fixed maturities	1,175.5	644.5
Gross unrealized losses, fixed maturities	12.6	11.6
Fair value, fixed maturities	9,167.8	7,490
Corporate debt securities
Available-for-sale securities
Amortized cost, fixed maturities	41,289.9	36,993.1
Gross unrealized gains, fixed maturities	6,160.9	3,706.5
Gross unrealized losses, fixed maturities	95.1	52.2
Allowance, fixed maturities	0.9
Fair value, fixed maturities	47,354.8	40,647.4
Residential mortgage-backed pass-through securities
Available-for-sale securities
Amortized cost, fixed maturities	2,857.6	2,913.9
Gross unrealized gains, fixed maturities	129.4	72.3
Gross unrealized losses, fixed maturities	0.2	3.8
Fair value, fixed maturities	2,986.8	2,982.4
Commercial mortgage-backed securities
Available-for-sale securities
Amortized cost, fixed maturities	4,741.2	4,746.6
Gross unrealized gains, fixed maturities	241.3	127.6
Gross unrealized losses, fixed maturities	35.9	24
Allowance, fixed maturities	4.3
Fair value, fixed maturities	4,942.3	4,850.2
Other-than-temporary impairments in AOCI		15.8
Collateralized debt obligations
Available-for-sale securities
Amortized cost, fixed maturities	4,045.9	3,226.7
Gross unrealized gains, fixed maturities	8.7	2.9
Gross unrealized losses, fixed maturities	24.9	14.3
Allowance, fixed maturities	2.2
Fair value, fixed maturities	4,027.5	3,215.3
Other-than-temporary impairments in AOCI		0.9
Other debt obligations
Available-for-sale securities
Amortized cost, fixed maturities	6,832.6	8,085.8
Gross unrealized gains, fixed maturities	243.2	129.6
Gross unrealized losses, fixed maturities	29.9	14.9
Fair value, fixed maturities	$ 7,045.9	8,200.5
Other-than-temporary impairments in AOCI		$ 31.7

Investments - Amortization by E

Investments - Amortization by Expected Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Amortized cost of fixed maturities available-for-sale
Due in one year or less	$ 2,336.5
Due after one year through five years	10,831.5
Due after five years through ten years	14,032.7
Due after ten years	24,868.8
Subtotal	52,069.5
Mortgage-backed and other asset-backed securities	18,477.3
Amortized cost, fixed maturities	70,546.8	$ 65,302.5
Fair value of fixed maturities available-for-sale
Due in one year or less	2,372.9
Due after one year through five years	11,570
Due after five years through ten years	15,601.5
Due after ten years	30,163.4
Subtotal	59,707.8
Mortgage-backed and other asset-backed securities	19,002.5
Fair value, fixed maturities	$ 78,710.3	$ 70,106.2

Investments - Net Investment In

Investments - Net Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Major categories of net investment income
Gross investment income (loss)	$ 4,001.2	$ 4,116.5	$ 3,731.6
Investment expenses	(110.6)	(118.1)	(102.4)
Net investment income (loss)	3,890.6	3,998.4	3,629.2
Fixed maturities | Available-for-sale
Major categories of net investment income
Gross investment income (loss)	2,660.5	2,606	2,479.9
Fixed maturities | Trading
Major categories of net investment income
Gross investment income (loss)	18.7	23.8	26.4
Equity securities
Major categories of net investment income
Gross investment income (loss)	62.8	110.5	38.8
Mortgage loans
Major categories of net investment income
Gross investment income (loss)	724.7	707	641.4
Real estate
Major categories of net investment income
Gross investment income (loss)	180.8	191.1	158.8
Policy loans
Major categories of net investment income
Gross investment income (loss)	41.6	44	45
Cash and cash equivalents
Major categories of net investment income
Gross investment income (loss)	17.4	65.3	56.2
Derivatives
Major categories of net investment income
Gross investment income (loss)	(1.8)	(2)	0.1
Other investment types
Major categories of net investment income
Gross investment income (loss)	$ 296.5	$ 370.8	$ 285

Investments - Net Realized Capi

Investments - Net Realized Capital Gains and Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Major components of net realized capital gains (losses) on investments
Fixed maturities, available-for-sale: Gross gains	$ 134.2	$ 15.5	$ 40.2
Fixed maturities, available-for-sale: Gross losses	(48.5)	(15.3)	(74.8)
Fixed maturities, available-for-sale: Net credit loss	(22.9)
Fixed maturities, available-for-sale: Net credit loss		(43.5)	(29.1)
Fixed maturities, available-for-sale: Hedging, net	(9.7)	(9.3)	(39.6)
Fixed maturities, trading	3.2	43	(9)
Equity securities	70.5	84.5	(17.7)
Mortgage loans gains (losses)	(15.5)	3	6.2
Derivative net realized capital gains (losses)	77.3	(120.3)	11.7
Other gains (losses)	114	(10.4)	36.7
Net realized capital gains (losses)	302.6	(52.8)	(75.4)
Unrealized gains (losses) on fixed maturities, trading	5.3	32.8	(12.2)
Unrealized gains (losses) on equity securities	64.6	61.6	(39.9)
Unrealized gains (losses) on equity securities reported in net investment income	35.2	66.9	4.9
Proceeds from sales of investments
Proceeds from sales of investments in fixed maturities, available-for-sale	$ 2,421.9	$ 1,654.8	$ 3,067.2

Investments - Allowance for Cre

Investments - Allowance for Credit Loss (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Rollforward of the allowance for credit loss by major security type
Additions for credit losses not previously recorded	$ 16.2
Reductions for securities sold during the period	(7)
Additional increases (decreases) for credit losses on securities with an allowance recorded in the previous period	0.2
Write-offs charged against allowance	(2.6)
Foreign currency translation adjustment	0.6
Ending balance	7.4
Corporate debt securities
Rollforward of the allowance for credit loss by major security type
Additions for credit losses not previously recorded	13.2
Reductions for securities sold during the period	(7)
Additional increases (decreases) for credit losses on securities with an allowance recorded in the previous period	(5.9)
Foreign currency translation adjustment	0.6
Ending balance	0.9
Commercial mortgage-backed securities
Rollforward of the allowance for credit loss by major security type
Additions for credit losses not previously recorded	2.9
Additional increases (decreases) for credit losses on securities with an allowance recorded in the previous period	4
Write-offs charged against allowance	(2.6)
Ending balance	4.3
Collateralized debt obligations
Rollforward of the allowance for credit loss by major security type
Additions for credit losses not previously recorded	0.1
Additional increases (decreases) for credit losses on securities with an allowance recorded in the previous period	2.1
Ending balance	$ 2.2

Investments - Other-Than-Tempor

Investments - Other-Than-Temporary Impairments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other-than-temporary impairment losses, net of recoveries
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		$ (9.3)	$ (46.3)
Net other-than-temporary impairment (losses) recoveries on available-for-sale securities		(38.3)	10.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income		(5.2)	(39.7)
Net impairment (losses) recoveries on available-for-sale securities		(43.5)	(29.1)
Net realized capital gains (losses)	$ 302.6	$ (52.8)	$ (75.4)

Investments - Accumulated Credi

Investments - Accumulated Credit Losses for Fixed Maturities with Bifurcated Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Other-Than-Temporary Impairment Credit Losses Recognized in Net Income - Rollforward
Beginning balance	$ (117.5)	$ (124.3)
Credit losses for which an other-than-temporary impairment was not previously recognized	(6.8)	(11.3)
Credit losses for which an other-than-temporary impairment was previously recognized	(11.8)	(20)
Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold	54.3	29.5
Net reduction (increase) for positive changes in cash flows expected to be collected and amortization	0.8	8.6
Ending balance	$ (81)	$ (117.5)

Investments - Gross Unrealized

Investments - Gross Unrealized Losses for Fixed Maturities (Details) $ in Millions	Dec. 31, 2020USD ($)item$ / shares	Dec. 31, 2019USD ($)item
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	$ 5,909.4	$ 5,390.1
Fixed maturities, Less than twelve months, Gross unrealized losses	138.8	63
Fixed maturities, Greater than or equal to twelve months, Fair value	1,399.1	3,134.9
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	67.4	61
Fixed maturities, Total, Fair value	7,308.5	8,525
Fixed maturities, Total, Gross unrealized losses	206.2	124
U.S. government and agencies
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	351.1	100
Fixed maturities, Less than twelve months, Gross unrealized losses	10.4	1.9
Fixed maturities, Greater than or equal to twelve months, Fair value		74.2
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses		1.1
Fixed maturities, Total, Fair value	351.1	174.2
Fixed maturities, Total, Gross unrealized losses	10.4	3
Non-U.S. governments
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value		17.6
Fixed maturities, Less than twelve months, Gross unrealized losses		0.2
Fixed maturities, Greater than or equal to twelve months, Fair value		12.4
Fixed maturities, Total, Fair value		30
Fixed maturities, Total, Gross unrealized losses		0.2
States and political subdivisions
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	363.5	559.9
Fixed maturities, Less than twelve months, Gross unrealized losses	12.5	11.2
Fixed maturities, Greater than or equal to twelve months, Fair value		86.3
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses		0.4
Fixed maturities, Total, Fair value	363.5	646.2
Fixed maturities, Total, Gross unrealized losses	12.5	11.6
Corporate debt securities
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	1,578.7	1,041.5
Fixed maturities, Less than twelve months, Gross unrealized losses	54.4	27.8
Fixed maturities, Greater than or equal to twelve months, Fair value	267.9	394.7
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	40.6	24.4
Fixed maturities, Total, Fair value	1,846.6	1,436.2
Fixed maturities, Total, Gross unrealized losses	95	52.2
Residential mortgage-backed pass-through securities
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	92.3	429.6
Fixed maturities, Less than twelve months, Gross unrealized losses	0.2	1.4
Fixed maturities, Greater than or equal to twelve months, Fair value	1.6	237.3
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses		2.4
Fixed maturities, Total, Fair value	93.9	666.9
Fixed maturities, Total, Gross unrealized losses	0.2	3.8
Commercial mortgage-backed securities
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	970.9	829.3
Fixed maturities, Less than twelve months, Gross unrealized losses	22.1	9.2
Fixed maturities, Greater than or equal to twelve months, Fair value	137.4	268.5
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	12.2	14.8
Fixed maturities, Total, Fair value	1,108.3	1,097.8
Fixed maturities, Total, Gross unrealized losses	34.3	24
Collateralized debt obligations
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	1,750.6	639.4
Fixed maturities, Less than twelve months, Gross unrealized losses	11.1	1.8
Fixed maturities, Greater than or equal to twelve months, Fair value	931.1	1,447.8
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	12.9	12.5
Fixed maturities, Total, Fair value	2,681.7	2,087.2
Fixed maturities, Total, Gross unrealized losses	24	14.3
Other debt obligations
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	802.3	1,772.8
Fixed maturities, Less than twelve months, Gross unrealized losses	28.1	9.5
Fixed maturities, Greater than or equal to twelve months, Fair value	61.1	613.7
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	1.7	5.4
Fixed maturities, Total, Fair value	863.4	2,386.5
Fixed maturities, Total, Gross unrealized losses	29.8	14.9
Principal Life Insurance Company
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Less than twelve months, Fair value	5,638.3	5,302.7
Fixed maturities, Less than twelve months, Gross unrealized losses	122.4	44
Fixed maturities, Greater than or equal to twelve months, Fair value	1,391.3	3,078
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	51.5	59.9
Fixed maturities, Total, Fair value	7,029.6	8,380.7
Fixed maturities, Total, Gross unrealized losses	$ 173.9	$ 103.9
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Percent Investment Grade (as a percent)	89.00%	97.00%
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Average Price (percent of carrying value to amortized cost)	98	99
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less Than Twelve Months | item	619	882
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Less Than Twelve Months (percent of carrying value to amortized cost)	98	99
Available-for-sale Securities in Unrealized Loss Positions, Percent Investment Grade, Less Than Twelve Months (as a percent)	89.00%	98.00%
Available-for-sale Securities in Unrealized Loss Position, Aggregate Losses On Investment Grade Investments, Less Than Twelve Months	$ 98.4	$ 43.1
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Twelve Months or Longer | item	198	502
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Twelve Months or Longer (percent of carrying value to amortized cost) | item	96	98
Principal Life Insurance Company | Corporate debt securities
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	$ 24.9	$ 23.6
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Twelve Months or Longer (percent of carrying value to amortized cost) | item	92	94
Principal Life Insurance Company | Commercial mortgage-backed securities
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses		$ 14.6
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Twelve Months or Longer (percent of carrying value to amortized cost) | item		95
Principal Life Insurance Company | Collateralized debt obligations
Gross Unrealized Losses for Fixed Maturities
Fixed maturities, Greater than or equal to twelve months, Gross unrealized losses	$ 12.9
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Twelve Months or Longer (percent of carrying value to amortized cost) | item	99

Investments - Net Unrealized Ga

Investments - Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments
Net unrealized gains (losses) on fixed maturities, available-for-sale	$ 8,193	$ 4,834.2
Noncredit component of impairment losses on fixed maturities, available-for-sale		(48.4)
Net unrealized gains (losses) on derivative instruments	38.9	94.1
Adjustments for assumed changes in amortization patterns	(437.3)	(261)
Adjustments for assumed changes in policyholder liabilities	(2,603.9)	(1,133.5)
Net unrealized gains (losses) on other investments and noncontrolling interest adjustments	78	96.8
Provision for deferred income tax benefits (taxes)	(1,112.2)	(766.9)
Net unrealized gains (losses) on available-for-sale securities and derivative instruments	$ 4,156.5	$ 2,815.3

Investments - Mortgage Loan Cre

Investments - Mortgage Loan Credit Monitoring (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost	$ 18,103.9	$ 16,513.9	$ 15,364.3
Reinsurance recoverables	1,098
Accrued interest receivable	552.5
Commercial mortgage loans
Financing Receivable, Credit Quality Indicator
2020	2,019.8
2019	2,769.9
2018	2,817.2
2017	2,049.3
2016	1,509.3
Prior	4,276.1
Mortgage loans, Total amortized cost	15,441.6	15,017.2	13,996.3
Accrued interest receivable	60
Commercial mortgage loans | A- and above
Financing Receivable, Credit Quality Indicator
2020	1,807.6
2019	2,486.8
2018	2,464.7
2017	1,780.8
2016	1,417.8
Prior	3,697
Mortgage loans, Total amortized cost	13,654.7	13,961.9
Commercial mortgage loans | BBB+ thru BBB-
Financing Receivable, Credit Quality Indicator
2020	149.1
2019	194.1
2018	352.5
2017	262.7
2016	75.8
Prior	499.7
Mortgage loans, Total amortized cost	1,533.9	1,026.9
Commercial mortgage loans | BB+ thru BB-
Financing Receivable, Credit Quality Indicator
2020	23.7
2019	69
2016	9.1
Prior	43.9
Mortgage loans, Total amortized cost	145.7	23.3
Commercial mortgage loans | B+ and below
Financing Receivable, Credit Quality Indicator
2020	39.4
2019	20
2017	5.8
2016	6.6
Prior	35.5
Mortgage loans, Total amortized cost	107.3	5.1
Brick and mortar
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		14,856.7
Brick and mortar | A- and above
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		13,885.2
Brick and mortar | BBB+ thru BBB-
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		943.1
Brick and mortar | BB+ thru BB-
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		23.3
Brick and mortar | B+ and below
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		5.1
Credit tenant loans
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		160.5
Credit tenant loans | A- and above
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		76.7
Credit tenant loans | BBB+ thru BBB-
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		83.8
Direct financing leases
Financing Receivable, Credit Quality Indicator
2020	209.7
2019	29.6
2018	65.8
2017	37.6
2016	19.3
Prior	348.8
Mortgage loans, Total amortized cost	710.8
Accrued interest receivable	0.5
Direct financing leases | A- and above
Financing Receivable, Credit Quality Indicator
2020	43.9
2019	1.6
2018	42.6
2017	19.2
2016	15.3
Prior	202.9
Mortgage loans, Total amortized cost	325.5
Direct financing leases | BBB+ thru BBB-
Financing Receivable, Credit Quality Indicator
2020	94.9
2019	5.5
2018	11.3
2017	18.4
2016	3
Prior	35.5
Mortgage loans, Total amortized cost	168.6
Direct financing leases | BB+ thru BB-
Financing Receivable, Credit Quality Indicator
2020	13.3
Prior	1.9
Mortgage loans, Total amortized cost	15.2
Direct financing leases | B+ and below
Financing Receivable, Credit Quality Indicator
2020	57.6
2019	22.5
2018	11.9
2016	1
Prior	108.5
Mortgage loans, Total amortized cost	201.5
Residential mortgage loans
Financing Receivable, Credit Quality Indicator
2020	699.1
2019	338.7
2018	167.8
2017	166.5
2016	168
Prior	411.4
Mortgage loans, Total amortized cost	1,951.5	1,496.7	$ 1,368
Accrued interest receivable	2
Residential mortgage loans | Performing
Financing Receivable, Credit Quality Indicator
2020	699.1
2019	336.7
2018	167
2017	165.1
2016	167.6
Prior	398.7
Mortgage loans, Total amortized cost	1,934.2	1,482.2
Residential mortgage loans | Non-performing
Financing Receivable, Credit Quality Indicator
2019	2
2018	0.8
2017	1.4
2016	0.4
Prior	12.7
Mortgage loans, Total amortized cost	$ 17.3	14.5
Mortgage loans, Days delinquent to be considered non-performing	90 days
First liens
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		1,485.7
First liens | Performing
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		1,474.2
First liens | Non-performing
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		11.5
Home equity
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		11
Home equity | Performing
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		8
Home equity | Non-performing
Financing Receivable, Credit Quality Indicator
Mortgage loans, Total amortized cost		$ 3

Investments - Financing Receiva

Investments - Financing Receivable, Non-Accrual and Aging (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing receivables, non-accrual and aging disclosures
Financing receivables, Non-accrual status	$ 21.5	$ 11.8
Financing receivables, Non-accrual assets without a valuation allowance	0.7
Financing receivables, Nonaccrual, Interest Income	0
Past due	152.8	68.2
Current	17,951.1	16,445.7
Financing receivables, Total amortized cost	18,103.9	16,513.9	$ 15,364.3
Recorded investment 90 days or more past due and accruing	7.8	2.7
Reinsurance recoverables	0
30 to 59 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	108.7	47.4
60 to 89 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	21.2	9.3
90 Days or More Past Due
Financing receivables, non-accrual and aging disclosures
Past due	22.9	11.5
Commercial mortgage loans
Financing receivables, non-accrual and aging disclosures
Financing receivables, Non-accrual status	10.7	5
Past due	63.3
Current	15,378.3
Financing receivables, Total amortized cost	15,441.6	15,017.2	13,996.3
Recorded investment 90 days or more past due and accruing	1.3
Commercial mortgage loans | 30 to 59 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	42.1
Commercial mortgage loans | 60 to 89 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	9.2
Commercial mortgage loans | 90 Days or More Past Due
Financing receivables, non-accrual and aging disclosures
Past due	12
Brick and mortar
Financing receivables, non-accrual and aging disclosures
Current		14,856.7
Financing receivables, Total amortized cost		14,856.7
Credit tenant loans
Financing receivables, non-accrual and aging disclosures
Current		160.5
Financing receivables, Total amortized cost		160.5
Direct financing leases
Financing receivables, non-accrual and aging disclosures
Past due	3.2
Current	707.6
Financing receivables, Total amortized cost	710.8
Direct financing leases | 60 to 89 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	3.2
Residential mortgage loans
Financing receivables, non-accrual and aging disclosures
Financing receivables, Non-accrual status	10.8	6.8
Financing receivables, Non-accrual assets without a valuation allowance	0.7
Past due	86.3
Current	1,865.2
Financing receivables, Total amortized cost	1,951.5	1,496.7	$ 1,368
Recorded investment 90 days or more past due and accruing	6.5
Residential mortgage loans | 30 to 59 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	66.6
Residential mortgage loans | 60 to 89 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due	8.8
Residential mortgage loans | 90 Days or More Past Due
Financing receivables, non-accrual and aging disclosures
Past due	$ 10.9
First liens
Financing receivables, non-accrual and aging disclosures
Financing receivables, Non-accrual status		8.8
Past due		67.1
Current		1,418.6
Financing receivables, Total amortized cost		1,485.7
Recorded investment 90 days or more past due and accruing		2.7
First liens | 30 to 59 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due		46.6
First liens | 60 to 89 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due		9.3
First liens | 90 Days or More Past Due
Financing receivables, non-accrual and aging disclosures
Past due		11.2
Home equity
Financing receivables, non-accrual and aging disclosures
Financing receivables, Non-accrual status		3
Past due		1.1
Current		9.9
Financing receivables, Total amortized cost		11
Home equity | 30 to 59 Days Past Due
Financing receivables, non-accrual and aging disclosures
Past due		0.8
Home equity | 90 Days or More Past Due
Financing receivables, non-accrual and aging disclosures
Past due		$ 0.3

Investments - Mortgage Loan Val

Investments - Mortgage Loan Valuation Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Changes in financing receivable valuation allowance
Beginning balance, Financing receivable valuation allowance	$ 33.1	$ 27	$ 27.4	$ 32.7
Provision: Financing receivable valuation allowance	17.3		(3)	(6)
Charge-offs: Financing receivable valuation allowance	(0.9)		(0.6)	(2.4)
Recoveries: Financing receivable valuation allowance	2.8		3.2	3.1
Effect of exchange rates: Financing receivable valuation allowance	0.6
Ending balance, Financing receivable valuation allowance	52.9	52.9	27	27.4
Individually evaluated for impairment, Financing receivable valuation allowance			1.4	1.4
Collectively evaluated for impairment, Financing receivable valuation allowance			25.6	26
Individually evaluated for impairment, Financing receivable			11.4	9.2
Collectively evaluated for impairment, Financing receivable			16,502.5	15,355.1
Financing receivables, Total amortized cost	18,103.9	$ 18,103.9	16,513.9	15,364.3
Commercial mortgage loans
Financing receivable valuation allowance disclosures
Mortgage loans, Days delinquent to be analyzed for valuation allowance		60 days
Accrued interest receivable written off		$ 0
Changes in financing receivable valuation allowance
Beginning balance, Financing receivable valuation allowance	27.3	24.5	24.3	25.8
Provision: Financing receivable valuation allowance	15.5		0.2	(1.5)
Effect of exchange rates: Financing receivable valuation allowance	0.4
Ending balance, Financing receivable valuation allowance	43.2	43.2	24.5	24.3
Collectively evaluated for impairment, Financing receivable valuation allowance			24.5	24.3
Collectively evaluated for impairment, Financing receivable			15,017.2	13,996.3
Financing receivables, Total amortized cost	15,441.6	15,441.6	15,017.2	13,996.3
Direct financing leases
Changes in financing receivable valuation allowance
Provision: Financing receivable valuation allowance	0.1
Ending balance, Financing receivable valuation allowance	0.1	0.1
Financing receivables, Total amortized cost	710.8	$ 710.8
Residential mortgage loans
Financing receivable valuation allowance disclosures
Mortgage loans, Days delinquent to be analyzed for valuation allowance		60 days
Accrued interest receivable written off		$ 0
Changes in financing receivable valuation allowance
Beginning balance, Financing receivable valuation allowance	3.3	2.5	3.1	6.9
Provision: Financing receivable valuation allowance	1.5		(3.2)	(4.5)
Charge-offs: Financing receivable valuation allowance	(0.9)		(0.6)	(2.4)
Recoveries: Financing receivable valuation allowance	2.8		3.2	3.1
Effect of exchange rates: Financing receivable valuation allowance	0.2
Ending balance, Financing receivable valuation allowance	6.9	6.9	2.5	3.1
Individually evaluated for impairment, Financing receivable valuation allowance			1.4	1.4
Collectively evaluated for impairment, Financing receivable valuation allowance			1.1	1.7
Individually evaluated for impairment, Financing receivable			11.4	9.2
Collectively evaluated for impairment, Financing receivable			1,485.3	1,358.8
Financing receivables, Total amortized cost	1,951.5	1,951.5	$ 1,496.7	$ 1,368
Reinsurance recoverables
Changes in financing receivable valuation allowance
Beginning balance, Financing receivable valuation allowance	2.5
Provision: Financing receivable valuation allowance	0.2
Ending balance, Financing receivable valuation allowance	$ 2.7	$ 2.7

Investments - Mortgage Loans (D

Investments - Mortgage Loans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 18,103.9	$ 16,513.9	$ 15,364.3
Commercial mortgage loans
Mortgage loan disclosures
Mortgage loans, purchased	166.8	200.5	127.5
Mortgage loans, sold	7.6	1.6	2.2
Mortgage loans, Total amortized cost	$ 15,441.6	$ 15,017.2	13,996.3
Percent of mortgage loans (as a percent)	100.00%	100.00%
Commercial mortgage loans | Office
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 4,491.7	$ 4,887.1
Percent of mortgage loans (as a percent)	29.00%	32.60%
Commercial mortgage loans | Retail
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 1,815.3	$ 2,052.6
Percent of mortgage loans (as a percent)	11.80%	13.70%
Commercial mortgage loans | Industrial
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 2,488.7	$ 2,268.5
Percent of mortgage loans (as a percent)	16.10%	15.10%
Commercial mortgage loans | Apartments
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 5,958	$ 5,246.9
Percent of mortgage loans (as a percent)	38.60%	34.90%
Commercial mortgage loans | Hotel
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 89.4	$ 90.8
Percent of mortgage loans (as a percent)	0.60%	0.60%
Commercial mortgage loans | Mixed use/other
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 598.5	$ 471.3
Percent of mortgage loans (as a percent)	3.90%	3.10%
Commercial mortgage loans | New England
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 593.9	$ 613.9
Percent of mortgage loans (as a percent)	3.80%	4.10%
Commercial mortgage loans | Middle Atlantic
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 4,438.2	$ 4,139.7
Percent of mortgage loans (as a percent)	28.80%	27.50%
Commercial mortgage loans | East North Central
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 572.6	$ 624.5
Percent of mortgage loans (as a percent)	3.70%	4.20%
Commercial mortgage loans | West North Central
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 267.5	$ 237.2
Percent of mortgage loans (as a percent)	1.70%	1.60%
Commercial mortgage loans | South Atlantic
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 2,368.9	$ 2,318.4
Percent of mortgage loans (as a percent)	15.30%	15.40%
Commercial mortgage loans | East South Central
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 316.6	$ 438.5
Percent of mortgage loans (as a percent)	2.10%	2.90%
Commercial mortgage loans | West South Central
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 1,315.9	$ 1,450
Percent of mortgage loans (as a percent)	8.50%	9.70%
Commercial mortgage loans | Mountain
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 936.2	$ 931.8
Percent of mortgage loans (as a percent)	6.10%	6.20%
Commercial mortgage loans | Pacific
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 4,183	$ 3,963.7
Percent of mortgage loans (as a percent)	27.10%	26.40%
Commercial mortgage loans | International
Mortgage loan disclosures
Mortgage loans, Total amortized cost	$ 448.8	$ 299.5
Percent of mortgage loans (as a percent)	2.90%	2.00%
Residential mortgage loans
Mortgage loan disclosures
Mortgage loans, purchased	$ 1,151.1	$ 489.2	394.2
Mortgage loans, sold	117.4	70.7	80.3
Mortgage loans, Total amortized cost	$ 1,951.5	$ 1,496.7	$ 1,368

Investments - Real Estate (Deta

Investments - Real Estate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Real estate
Depreciation expense on invested real estate	$ 65.3	$ 60	$ 54.1
Accumulated depreciation on invested real estate	$ 591.2	$ 526

Investments - Other Investments

Investments - Other Investments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summarized financial information of unconsolidated entities
Total assets	$ 296,627.7				$ 276,087.8				$ 296,627.7	$ 276,087.8
Total liabilities	279,754.8				261,137.1				279,754.8	261,137.1
Total stockholders' equity	16,617.3				14,685.8				16,617.3	14,685.8	$ 11,456	$ 12,921.9
Total revenues	3,765.1	$ 3,310.7	$ 3,114.6	$ 4,551.3	4,047.2	$ 4,458.4	$ 3,972.6	$ 3,743.9	14,741.7	16,222.1	14,237.2
Net income (loss)	491.5	$ 235.9	$ 416.1	$ 285	315.3	$ 284.6	$ 392.1	$ 452.1	1,428.5	1,444.1	1,553.7
Other Types of Investments
Direct financing leases	710.8				782.9				710.8	782.9
Cash surrender value of company owned life insurance	973.6				734.1				973.6	734.1
Certain sponsored investment funds carried at fair value	638.8				678.7				638.8	678.7
Unconsolidated entities
Summarized financial information of unconsolidated entities
Total assets	155,724.1				158,439.7				155,724.1	158,439.7
Total liabilities	73,438.2				88,455.8				73,438.2	88,455.8
Total stockholders' equity	82,285.9				69,983.9				82,285.9	69,983.9
Net investment in unconsolidated entities	$ 1,912.9				$ 1,825.5				1,912.9	1,825.5
Total revenues									14,989	17,802.2	15,389.4
Net income (loss)									7,757	7,938.3	6,542.1
Our share of net income of unconsolidated entities									$ 143.9	$ 222.5	$ 161.6

Investments - Securities Posted

Investments - Securities Posted as Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Securities Posted as Collateral
Commercial mortgage loans and residential first lien mortgages posted as collateral associated with obligation under funding agreements with the Federal Home Loan Bank of Des Moines	$ 4,604.9	$ 4,062
Fixed maturities available-for-sale and trading securities posted as collateral for a reinsurance arrangement, derivative credit support annex (collateral) agreements, Futures Commission Merchant agreements, a lending arrangement and an obligation under funding agreements with Federal Home Loan Bank of Des Moines	2,563.9	2,749.4
Securities posted as collateral eligible to be sold or repledged	$ 133.4	$ 163.9

Investments - Balance Sheet Off

Investments - Balance Sheet Offsetting, Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financial Asset Offsetting
Gross amount of recognized assets subject to netting agreements	$ 527.2	$ 312.3
Amount of liabilities that offset the gross amount of assets subject to netting agreements not offset in statement of financial position	(132.5)	(88.4)
Collateral received, financial assets	(357.2)	(221.2)
Net amount of assets subject to netting agreements	37.5	2.7
Derivative assets
Financial Asset Offsetting
Gross amount of recognized assets subject to netting agreements	463.5	288.7
Amount of liabilities that offset the gross amount of assets subject to netting agreements not offset in statement of financial position	(132.5)	(88.4)
Collateral received, financial assets	(293.5)	(197.6)
Net amount of assets subject to netting agreements	37.5	2.7
Gross amount of assets not subject to netting agreements	0	6
Reverse repurchase agreements
Financial Asset Offsetting
Gross amount of recognized assets subject to netting agreements	63.7	23.6
Collateral received, financial assets	$ (63.7)	$ (23.6)

Investments - Balance Sheet O_2

Investments - Balance Sheet Offsetting, Liabilities (Details) - Derivative liabilities - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financial Liability Offsetting
Gross amount of recognized liabilities subject to netting agreements	$ 186.2	$ 216
Amount of assets that offset the gross amount of liabilities subject to netting agreements not offset in statement of financial position	(132.5)	(88.4)
Collateral pledged, financial liabilities	(45.7)	(118.3)
Net amount of liabilities subject to netting agreements	8	9.3
Gross amount of liabilities not subject to netting agreements	$ 467.8	$ 314.5

Derivative Financial Instrume_3

Derivative Financial Instruments - Notional Amounts and Credit Exposure (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Derivative Financial Instruments, exposure
Cash and securities posted under collateral arrangements associated with derivative credit support agreements and Futures Commission Merchant agreements	$ 148.3	$ 271.6
Aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position	180.2	164.7
Collateral and initial margin posted supporting derivatives with credit-risk-related contingent features that were in a liability position	148.3	271.6
Additional collateral required to be posted if derivative credit-risk-related contingent features were triggered	44.4
Cash collateral received associated with derivative credit support annex agreements and Futures Commission Merchant agreements	225.2	156.8
Notional amount	62,292.5	50,787.9
Gross credit exposure	473.5	301.6
Less: collateral received	294.7	208.3
Net credit exposure	178.8	93.3
Interest rate swaps
Derivative Financial Instruments, exposure
Cash exchanged under contract	0
Principal payments made under contract	0
Notional amount	44,472.1	35,173.6
Gross credit exposure	291	181.9
Interest rate options
Derivative Financial Instruments, exposure
Notional amount	2,083.9	1,416.9
Gross credit exposure	51	28.3
Interest rate forwards
Derivative Financial Instruments, exposure
Notional amount	1,000
Gross credit exposure	6.2
Interest rate futures
Derivative Financial Instruments, exposure
Notional amount	188.5	142.5
Swaptions
Derivative Financial Instruments, exposure
Notional amount	62	62
Currency forwards
Derivative Financial Instruments, exposure
Notional amount	1,115.8	1,182.3
Gross credit exposure	45.4	4.9
Currency swaps
Derivative Financial Instruments, exposure
Notional amount	1,045.5	1,027.2
Gross credit exposure	43.3	55.4
Currency options
Derivative Financial Instruments, exposure
Notional amount		53.8
Gross credit exposure		0.1
Equity options
Derivative Financial Instruments, exposure
Notional amount	1,857.8	1,672.8
Gross credit exposure	33.2	30.5
Equity futures
Derivative Financial Instruments, exposure
Notional amount	218.1	149.5
Credit default swaps
Derivative Financial Instruments, exposure
Notional amount	295	165
Gross credit exposure	3.4	0.5
Embedded derivative financial instruments
Derivative Financial Instruments, exposure
Notional amount	$ 9,953.8	$ 9,742.3

Derivative Financial Instrume_4

Derivative Financial Instruments - Fair Value of Derivatives (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, fair value disclosures
Derivative instruments, assets	$ 463.5	$ 294.7
Derivative instruments, liabilities	654	530.5
Fair value of embedded derivative liabilities reported with contractholder funds	467.8	214.2
Derivatives designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	21.1	30
Derivative instruments, liabilities	72.5	36.5
Derivatives not designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	442.4	264.7
Derivative instruments, liabilities	581.5	494
Interest rate contracts | Derivatives designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, liabilities	27.8	21.3
Interest rate contracts | Derivatives not designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	339.3	204.2
Derivative instruments, liabilities	33	16.7
Foreign exchange contracts | Derivatives designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	21.1	30
Derivative instruments, liabilities	44.7	15.2
Foreign exchange contracts | Derivatives not designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	66.5	29.5
Derivative instruments, liabilities	29.2	100.2
Equity contracts | Derivatives not designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	33.2	30.5
Derivative instruments, liabilities	49	63.1
Credit contracts | Derivatives not designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, assets	3.4	0.5
Derivative instruments, liabilities	2.5	1.2
Other contracts | Derivatives not designated as hedging instruments
Derivatives, fair value disclosures
Derivative instruments, liabilities	$ 467.8	$ 312.8

Derivative Financial Instrume_5

Derivative Financial Instruments - Credit Derivatives Sold (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Credit default swaps
Credit derivatives sold disclosures
Notional amount	$ 170	$ 90
Fair value	3.3	0.5
Maximum future payments	$ 170	$ 90
Weighted average expected life	3 years 9 months 18 days	2 years 4 months 24 days
Single name credit default swaps | Corporate debt securities | A
Credit derivatives sold disclosures
Notional amount	$ 20	$ 5
Fair value	0.5
Maximum future payments	$ 20	$ 5
Weighted average expected life	4 years 6 months	6 months
Single name credit default swaps | Corporate debt securities | BBB
Credit derivatives sold disclosures
Notional amount	$ 115	$ 70
Fair value	2.1	0.2
Maximum future payments	$ 115	$ 70
Weighted average expected life	3 years 10 months 24 days	2 years 7 months 6 days
Single name credit default swaps | Sovereign | A
Credit derivatives sold disclosures
Notional amount	$ 20
Fair value	0.6
Maximum future payments	$ 20
Weighted average expected life	4 years 6 months
Single name credit default swaps | Sovereign | BBB
Credit derivatives sold disclosures
Notional amount	$ 15	$ 15
Fair value	0.1	0.3
Maximum future payments	$ 15	$ 15
Weighted average expected life	1 year	2 years

Derivative Financial Instrume_6

Derivative Financial Instruments - Fair Value Hedges (Details) - Fixed maturities, available-for-sale - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value Hedges
Amortized cost of hedged item - Active hedging relationships	$ 476.1	$ 142
Amortized cost of hedged item - Discontinued hedging relationships	135.1	159.3
Amortized cost of hedged item - Active or discontinued hedging relationships	611.2	301.3
Cumulative amount of fair value hedging basis adjustment - Active hedging relationships	21.4	18.1
Cumulative amount of fair value hedging basis adjustment - Discontinued hedging relationships	5.2	7.7
Cumulative amount of fair value hedging basis adjustment - Active or discontinued hedging relationships	$ 26.6	$ 25.8

Derivative Financial Instrume_7

Derivative Financial Instruments - Cash Flow Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flow Hedges
Amount of gain (loss) recognized in AOCI on derivatives in cash flow hedging relationships	$ (40.1)	$ (19.3)	$ 57.4
Net gains (losses) expected to be reclassified from accumulated OCI into net income in the next 12 months	23.5
Interest rate contracts | Fixed maturities, available-for-sale
Cash Flow Hedges
Amount of gain (loss) recognized in AOCI on derivatives in cash flow hedging relationships	(3)	(9.9)	36.7
Foreign exchange contracts | Fixed maturities, available-for-sale
Cash Flow Hedges
Amount of gain (loss) recognized in AOCI on derivatives in cash flow hedging relationships	$ (37.1)	$ (9.4)	20.8
Foreign exchange contracts | Investment contracts
Cash Flow Hedges
Amount of gain (loss) recognized in AOCI on derivatives in cash flow hedging relationships			$ (0.1)

Derivative Financial Instrume_8

Derivative Financial Instruments - Effect of Hedges on Consolidated Statements of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Gains (losses) recognized for hedging relationships
Net investment income (loss)	$ 3,890.6	$ 3,998.4	$ 3,629.2
Net realized capital gains (losses)	302.6	(52.8)	(75.4)
Benefits, claims and settlement expenses	8,281.5	9,905.8	8,192.5
Operating expenses	4,646.5	4,503.9	4,136.7
Fair Value Hedges | Interest rate contracts | Net investment income
Gains (losses) recognized for hedging relationships
Gain (loss) recognized on hedged item	3.3	5.7
Gain (loss) recognized on derivatives	(3.8)	(6)
Amortization of hedged item basis adjustments	(2.5)	(4.2)	(6.7)
Amounts related to periodic settlements on derivatives	(6.2)	(3.4)	(5.9)
Total gain (loss) recognized for hedging relationships	(9.2)	(7.9)	(12.6)
Fair Value Hedges | Interest rate contracts | Net realized capital gains (losses)
Gains (losses) recognized for hedging relationships
Gain (loss) recognized on hedged item			(6.6)
Gain (loss) recognized on derivatives			6.2
Total gain (loss) recognized for hedging relationships			(0.4)
Cash Flow Hedges | Net investment income
Gains (losses) recognized for hedging relationships
Total gain (loss) recognized for hedging relationships	26.3	27.2	26.9
Cash Flow Hedges | Net realized capital gains (losses)
Gains (losses) recognized for hedging relationships
Total gain (loss) recognized for hedging relationships	9.1	9	30
Cash Flow Hedges | Benefits, claims and settlement expenses
Gains (losses) recognized for hedging relationships
Total gain (loss) recognized for hedging relationships	(0.1)	(0.1)	(0.2)
Cash Flow Hedges | Operating expense
Gains (losses) recognized for hedging relationships
Total gain (loss) recognized for hedging relationships		(4.8)	(10.7)
Cash Flow Hedges | Interest rate contracts | Gain (loss) reclassified from AOCI on derivatives
Gains (losses) recognized for hedging relationships
Net investment income (loss)	18.1	19.8	20.9
Net realized capital gains (losses)	2.7	(0.6)	17
Benefits, claims and settlement expenses	0.1	0.1	0.1
Operating expenses		4.8	10.7
Cash Flow Hedges | Interest rate contracts | Net realized capital gains (losses)
Gains (losses) recognized for hedging relationships
Gain (loss) reclassified from AOCI into net income as a result that a forecasted transaction is no longer probable of occurring	0.1	0.1	0.3
Cash Flow Hedges | Foreign exchange contracts | Gain (loss) reclassified from AOCI on derivatives
Gains (losses) recognized for hedging relationships
Net realized capital gains (losses)	6.3	9.5	12.7
Cash Flow Hedges | Foreign exchange contracts | Net investment income
Gains (losses) recognized for hedging relationships
Amounts related to periodic settlements on derivatives	8.2	$ 7.4	6
Cash Flow Hedges | Foreign exchange contracts | Benefits, claims and settlement expenses
Gains (losses) recognized for hedging relationships
Amounts related to periodic settlements on derivatives			$ (0.1)
Net investment hedging relationships
Gains (losses) recognized for hedging relationships
Amount of gain (loss) recognized in accumulated OCI on derivatives	7.9
Net investment hedging relationships | Gain (loss) reclassified from AOCI on derivatives
Gains (losses) recognized for hedging relationships
Net realized capital gains (losses)	(7.1)
Net investment hedging relationships | Foreign exchange contracts
Gains (losses) recognized for hedging relationships
Amount of gain (loss) recognized in accumulated OCI on derivatives	7.9
Net investment hedging relationships | Foreign exchange contracts | Gain (loss) reclassified from AOCI on derivatives
Gains (losses) recognized for hedging relationships
Net realized capital gains (losses)	$ (7.1)

Derivative Financial Instrume_9

Derivative Financial Instruments - Derivatives Not Designated as Hedging Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations
Amount of gain (loss) recognized in net income on derivatives	$ 50.9	$ (145.2)	$ (15.9)
Interest rate contracts
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations
Amount of gain (loss) recognized in net income on derivatives	346.5	218	(27.6)
Foreign exchange contracts
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations
Amount of gain (loss) recognized in net income on derivatives	54.7	(58.6)	(64.2)
Equity contracts
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations
Amount of gain (loss) recognized in net income on derivatives	(96.6)	(132.9)	(31)
Credit contracts
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations
Amount of gain (loss) recognized in net income on derivatives	1.8	(3.6)	(1.6)
Other contracts
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations
Amount of gain (loss) recognized in net income on derivatives	$ (255.5)	$ (168.1)	$ 108.5

Closed Block - Assets and Liabi

Closed Block - Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Closed Block liabilities and assets designated to the Closed Block
Closed Block liabilities: Policyholder dividends obligation	$ 298.2	$ 202.7
Closed Block liabilities
Closed Block liabilities: Future policy benefits and claims	3,423.2	3,563.1
Closed Block liabilities: Other policyholder funds	6	6.6
Closed Block liabilities: Policyholder dividends payable	189	199.1
Closed Block liabilities: Policyholder dividends obligation	298.2	202.7
Closed Block liabilities: Other liabilities	8.7	7.8
Total Closed Block liabilities	3,925.1	3,979.3
Assets designated to the Closed Block
Closed Block assets: Fixed maturities, available-for-sale	2,353.3	2,269.6
Closed Block assets: Fixed maturities, trading	2.6	2.6
Closed Block assets: Equity securities	1.1	1.1
Closed Block assets: Mortgage loans	565.9	622.8
Closed Block assets: Policy loans	456.8	486
Closed Block assets: Other investments	61.7	46.4
Closed Block assets: Total investments	3,441.4	3,428.5
Closed Block assets: Cash and cash equivalents	23.2	47.5
Closed Block assets: Accrued investment income	35.4	38.1
Closed Block assets: Premiums due and other receivables	8.3	9.7
Closed Block assets: Deferred tax asset	24.2	29.5
Total assets designated to the Closed Block	3,532.5	3,553.3
Excess of Closed Block liabilities over assets designated to the Closed Block	392.6	426
Amounts included in accumulated other comprehensive income (loss)	0.9	0.9
Maximum future earnings to be recognized from Closed Block assets and liabilities	$ 393.5	$ 426.9	$ 476.8	$ 532.1

Closed Block - Revenues and Exp

Closed Block - Revenues and Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Closed Block: Premiums and other considerations	$ 217.6	$ 227.6	$ 244.2
Closed Block: Net investment income (loss)	143.6	154.4	160.5
Closed Block: Net realized capital gains (losses)	16	7.4	(3.4)
Closed Block: Total revenues	377.2	389.4	401.3
Expenses
Closed Block: Benefits, claims and settlement expenses	212.8	204.4	211.5
Closed Block: Dividends to policyholders	117.8	116.3	120.9
Closed Block: Operating expenses	2.7	2.9	3.3
Closed Block: Total expenses	333.3	323.6	335.7
Closed Block revenues, net of Closed Block expenses, before income taxes	43.9	65.8	65.6
Closed Block: Income taxes (benefits)	8.4	12.9	11.1
Closed Block revenues, net of Closed Block expenses and income taxes	35.5	52.9	54.5
Funding adjustment charges	(2.2)	(3)	(0.5)
Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustments	$ 33.3	$ 49.9	$ 54

Closed Block - Change in Maximu

Closed Block - Change in Maximum Future Earnings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in maximum future earnings of the Closed Block
Maximum future earnings to be recognized from Closed Block assets and liabilities, Beginning of year	$ 426.9	$ 476.8	$ 532.1
Effects of implementation of accounting changes	0.1		1.3
Maximum future earnings to be recognized from Closed Block assets and liabilities, End of year	393.5	426.9	476.8
Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustment charges	$ (33.3)	$ (49.9)	$ (54)

Deferred Acquisition Costs (Det

Deferred Acquisition Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in deferred acquisition costs
Balance at beginning of year, deferred acquisition costs	$ 3,521.3	$ 3,693.5	$ 3,540.7
Costs deferred during the year	457	473.5	414.9
Amortization of deferred acquisition costs	(388.1)	(347)	(253.5)
Adjustment related to unrealized (gains) losses on available-for-sale securities and derivative instruments	(180.5)	(298.7)	184.9
Other			(193.5)
Balance at end of year, deferred acquisition costs	$ 3,409.7	$ 3,521.3	$ 3,693.5

Insurance Liabilities - Compone

Insurance Liabilities - Components of Contractholder Funds (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Liabilities for investment contracts:
Liabilities for individual annuities	$ 12,864.1	$ 13,457.5
GICs	11,858	10,423.5
Funding agreements	9,407.3	8,640.6
Other investment contracts	1,762.4	1,596.7
Total liabilities for investment contracts	35,891.8	34,118.3
Universal life and other reserves	7,345.9	7,249.2
Contractholder funds	$ 43,237.7	$ 41,367.5

Insurance Liabilities - Contrac

Insurance Liabilities - Contractholder Funding Agreements (Details) $ in Millions, € in Billions	12 Months Ended
	Dec. 31, 2020USD ($)item	Apr. 30, 2020USD ($)	Dec. 31, 2019USD ($)	Nov. 30, 2017USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2006USD ($)	Dec. 31, 2006EUR (€)	Mar. 31, 2004USD ($)	Dec. 31, 2001USD ($)	Dec. 31, 1998USD ($)
Funding agreement disclosures
Funding agreements	$ 9,407.3		$ 8,640.6
Principal Life Insurance Company
Funding agreement disclosures
Number of separate funding agreement programs | item	5
Number of funding agreement programs not guaranteed by PFG | item	3
Principal Life Insurance Company | FHLB Des Moines funding agreement program
Funding agreement disclosures
Funding agreements	$ 4,252.5		4,010.9
Principal Life Insurance Company | 1998 Funding agreement program
Funding agreement disclosures
Maximum authorized amount of funding agreements to be issued											$ 4,000
Funding agreements	75		75.2
Principal Life Insurance Company | 2006 Funding agreement program
Funding agreement disclosures
Maximum authorized amount of funding agreements to be issued							$ 5,300	€ 4
Funding agreements	122.4		112.2
Principal Life Insurance Company | 2001 Funding agreement program
Funding agreement disclosures
Maximum authorized amount of funding agreements to be issued										$ 7,000
Funding agreements	201.8		201.7
Principal Life Insurance Company | 2004 Funding agreement program
Funding agreement disclosures
Maximum authorized amount of funding agreements to be issued									$ 9,000
Funding agreements		$ 0	26.2
Principal Life Insurance Company | 2011 Funding agreement program
Funding agreement disclosures
Maximum authorized amount of funding agreements to be issued						$ 5,000
Funding agreements	$ 4,755.8		$ 4,214.3
Additional maximum authorized amount of funding agreements to be issued				$ 4,000	$ 4,000
Amount of funding agreement authorization used at time additional amount authorized					$ 5,000

Insurance Liabilities - Liabili

Insurance Liabilities - Liability for Unpaid Claims (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in unpaid claims
Balance at beginning of period, unpaid claims	$ 2,365.5	$ 2,252.7	$ 2,130.5
Balance at beginning of period, reinsurance recoverables for unpaid claims	403.8	404.3	375.8
Net balance at beginning of period, unpaid claims	1,961.7	1,848.4	1,754.7
Incurred:
Incurred: Current year	1,376.8	1,361.3	1,268.8
Incurred: Prior years	26.6	0.8	0.3
Total incurred	1,403.4	1,362.1	1,269.1
Payments:
Payments: Current year	863.8	869.4	815.7
Payments: Prior years	403.3	379.4	359.7
Total payments	1,267.1	1,248.8	1,175.4
Net balance at end of period, unpaid claims	2,098	1,961.7	1,848.4
Balance at end of period, reinsurance recoverables for unpaid claims	436.9	403.8	404.3
Balance at end of period, unpaid claims	2,534.9	2,365.5	2,252.7
Amount not included in the rollforward above:
Claim adjustment expense liabilities	$ 57.8	$ 57.9	$ 54.6

Insurance Liabilities - Claims

Insurance Liabilities - Claims Development Tables (Details) $ in Millions	Dec. 31, 2020USD ($)claim	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)
Claims Development
Total outstanding liabilities for unpaid claims net of reinsurance	$ 1,333.2
Long-Term Disability/Group Life Waiver
Claims Development
Net incurred claims	2,125.4
Net cumulative paid claims	1,156.8
Liability for unpaid claims net, not separately presented	240.2
Total outstanding liabilities for unpaid claims net of reinsurance	1,208.8
Long-Term Disability/Group Life Waiver | Incurral year 2011
Claims Development
Net incurred claims	167	$ 166.5	$ 167.6	$ 169.6	$ 172.3	$ 178.4	$ 184.8	$ 185.4	$ 192.6	$ 203.7
Incurred but not reported claims	$ 0.1
Cumulative number of reported claims | claim	6,294
Net cumulative paid claims	$ 129.7	125.4	119.3	112.6	105.2	95.4	85.7	72.5	50	$ 11.2
Long-Term Disability/Group Life Waiver | Incurral year 2012
Claims Development
Net incurred claims	173.1	171.9	173.3	174.8	181.8	189.5	191.1	200	217.9
Incurred but not reported claims	$ 0.1
Cumulative number of reported claims | claim	6,445
Net cumulative paid claims	$ 131.5	126.1	120	112.9	104.6	93.7	80.8	55.1	$ 13.8
Long-Term Disability/Group Life Waiver | Incurral year 2013
Claims Development
Net incurred claims	173.4	177.1	179.5	182.3	190.7	188.4	203.3	219.3
Incurred but not reported claims	$ 0.1
Cumulative number of reported claims | claim	7,050
Net cumulative paid claims	$ 129	123.2	116.4	106.4	97	81.4	55	$ 12.5
Long-Term Disability/Group Life Waiver | Incurral year 2014
Claims Development
Net incurred claims	202	201.9	206.2	218.1	214.4	231.4	242.2
Incurred but not reported claims	$ 0.1
Cumulative number of reported claims | claim	7,603
Net cumulative paid claims	$ 140.8	132.4	122.3	111.8	96.3	66	$ 16.1
Long-Term Disability/Group Life Waiver | Incurral year 2015
Claims Development
Net incurred claims	210	208.2	215.3	217.2	227.2	231
Incurred but not reported claims	$ 0.1
Cumulative number of reported claims | claim	7,179
Net cumulative paid claims	$ 137.1	126.8	114.6	98	67	$ 16.9
Long-Term Disability/Group Life Waiver | Incurral year 2016
Claims Development
Net incurred claims	214.4	219.5	219.4	228.4	229.8
Incurred but not reported claims	$ 0.1
Cumulative number of reported claims | claim	6,163
Net cumulative paid claims	$ 136.8	124.9	105.6	70.6	$ 16.2
Long-Term Disability/Group Life Waiver | Incurral year 2017
Claims Development
Net incurred claims	245.8	243.1	239.7	238.4
Incurred but not reported claims	$ 4.4
Cumulative number of reported claims | claim	6,074
Net cumulative paid claims	$ 135.9	115	76.5	$ 17.8
Long-Term Disability/Group Life Waiver | Incurral year 2018
Claims Development
Net incurred claims	239.2	245.1	239.4
Incurred but not reported claims	$ 6.6
Cumulative number of reported claims | claim	5,738
Net cumulative paid claims	$ 115.7	79.9	$ 20.1
Long-Term Disability/Group Life Waiver | Incurral year 2019
Claims Development
Net incurred claims	248.4	255.2
Incurred but not reported claims	$ 3.2
Cumulative number of reported claims | claim	5,858
Net cumulative paid claims	$ 79.7	19.2
Long-Term Disability/Group Life Waiver | Incurral year 2020
Claims Development
Net incurred claims	252.1
Incurred but not reported claims	$ 87
Cumulative number of reported claims | claim	3,588
Net cumulative paid claims	$ 20.6
Dental/Vision/Short-Term Disability/Critical Illness/Accident
Claims Development
Net incurred claims	1,391.4
Net cumulative paid claims	1,321
Total outstanding liabilities for unpaid claims net of reinsurance	70.4
Dental/Vision/Short-Term Disability/Critical Illness/Accident | Incurral year 2019
Claims Development
Net incurred claims	$ 711.6	724.7
Cumulative number of reported claims | claim	3,363,947
Net cumulative paid claims	$ 711.5	653.5
Dental/Vision/Short-Term Disability/Critical Illness/Accident | Incurral year 2020
Claims Development
Net incurred claims	679.8
Incurred but not reported claims	$ 45
Cumulative number of reported claims | claim	2,899,957
Net cumulative paid claims	$ 609.5
Group Life
Claims Development
Net incurred claims	495.2
Net cumulative paid claims	442.3
Liability for unpaid claims net, not separately presented	1.1
Total outstanding liabilities for unpaid claims net of reinsurance	54
Group Life | Incurral year 2019
Claims Development
Net incurred claims	224.6	228.3
Incurred but not reported claims	$ 0.7
Cumulative number of reported claims | claim	5,117
Net cumulative paid claims	$ 223	$ 181.7
Group Life | Incurral year 2020
Claims Development
Net incurred claims	270.6
Incurred but not reported claims	$ 21.9
Cumulative number of reported claims | claim	5,505
Net cumulative paid claims	$ 219.3

Insurance Liabilities - Reconci

Insurance Liabilities - Reconciliation of Unpaid Claims to Liability for Unpaid Claims Table (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities for unpaid claims	$ 1,333.2
Reconciling items
Reinsurance recoverable on unpaid claims	53.4
Impact of discounting	(214.5)
Liability for unpaid claims - short duration contracts	1,172.1
Insurance contracts other than short duration	1,362.8
Liability for unpaid claims	2,534.9	$ 2,365.5	$ 2,252.7	$ 2,130.5
Long-Term Disability/Group Life Waiver
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities for unpaid claims	1,208.8
Reconciling items
Reinsurance recoverable on unpaid claims	53.3
Impact of discounting	(214.5)	(215)
Liability for unpaid claims - short duration contracts	1,047.6	1,029.9
Dental/Vision/Short-Term Disability/Critical Illness/Accident
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities for unpaid claims	70.4
Reconciling items
Liability for unpaid claims - short duration contracts	70.4	71.2
Group Life
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities for unpaid claims	54
Reconciling items
Reinsurance recoverable on unpaid claims	0.1
Liability for unpaid claims - short duration contracts	$ 54.1	$ 50.4

Insurance Liabilities - Claim D

Insurance Liabilities - Claim Duration and Payout Table (Details)	Dec. 31, 2020
Long-Term Disability/Group Life Waiver
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	7.70%
Year 2	24.30%
Year 3	15.10%
Year 4	8.20%
Year 5	5.70%
Year 6	5.20%
Year 7	4.20%
Year 8	3.60%
Year 9	3.40%
Year 10	2.60%
Dental/Vision/Short-Term Disability/Critical Illness/Accident
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	91.70%
Year 2	8.00%
Group Life
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	81.50%
Year 2	17.30%

Insurance Liabilities - Discoun

Insurance Liabilities - Discounting Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Carrying amount of liabilities for unpaid claims	$ 1,172.1
Aggregate amount of discount	214.5
Long-Term Disability/Group Life Waiver
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Carrying amount of liabilities for unpaid claims	1,047.6	$ 1,029.9
Aggregate amount of discount	214.5	215
Interest accretion	$ 33.9	$ 34.2	$ 34.5
Long-Term Disability/Group Life Waiver | Minimum
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Discount rate	2.80%	3.30%
Long-Term Disability/Group Life Waiver | Maximum
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Discount rate	7.00%	7.00%
Dental/Vision/Short-Term Disability/Critical Illness/Accident
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Carrying amount of liabilities for unpaid claims	$ 70.4	$ 71.2
Group Life
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Carrying amount of liabilities for unpaid claims	$ 54.1	$ 50.4

Debt - Short-Term Debt (Details

Debt - Short-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Short-Term Debt
Credit facilities	$ 986.6	$ 994.5
Short-term debt	$ 84.7	$ 93.4
Weighted-average interest rates on short-term borrowings (as a percent)	3.40%	3.40%
Credit facility maturing November 2023 | PFG, PFS, Principal Life as co-borrowers
Short-Term Debt
Credit facilities	$ 600	$ 600
Credit facility maturing November 2023 | PFG, PFS, Principal Life and Principal Financial Services V (UK) LTD as co-borrowers
Short-Term Debt
Credit facilities	200	200
Unsecured lines of credit | Principal International Chile
Short-Term Debt
Credit facilities	186.6	134.5
Short-term debt	$ 84.7	$ 93.4
Unsecured lines of credit | Maximum | Principal International Chile
Short-Term Debt
Term of credit facility	1 year	1 year
Unsecured line of credit maturing September 2020 | Principal Life Insurance Company
Short-Term Debt
Credit facilities		$ 60
Commercial paper
Short-Term Debt
Support provided by back-stop facility for commercial paper program (as a percent)	100.00%	100.00%
Back-stop facility outstanding balances	$ 0	$ 0

Debt - Components of Long-Term

Debt - Components of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Long-Term Debt
Long-term debt principal	$ 4,311.1	$ 3,763.2
Net unamortized discount, premium and debt issuance costs	(31.9)	(29.1)
Long-term debt carrying amount	$ 4,279.2	$ 3,734.1
3.3% notes payable, due 2022
Long-Term Debt
Interest rate (as a percent)	3.30%	3.30%
Long-term debt principal	$ 300	$ 300
Net unamortized discount, premium and debt issuance costs	(0.7)	(1)
Long-term debt carrying amount	$ 299.3	$ 299
3.125% notes payable, due 2023
Long-Term Debt
Interest rate (as a percent)	3.125%	3.125%
Long-term debt principal	$ 300	$ 300
Net unamortized discount, premium and debt issuance costs	(0.7)	(1)
Long-term debt carrying amount	$ 299.3	$ 299
3.4% notes payable, due 2025
Long-Term Debt
Interest rate (as a percent)	3.40%	3.40%
Long-term debt principal	$ 400	$ 400
Net unamortized discount, premium and debt issuance costs	(2.2)	(2.6)
Long-term debt carrying amount	$ 397.8	$ 397.4
3.1% notes payable, due 2026
Long-Term Debt
Interest rate (as a percent)	3.10%	3.10%
Long-term debt principal	$ 350	$ 350
Net unamortized discount, premium and debt issuance costs	(2.1)	(2.5)
Long-term debt carrying amount	$ 347.9	$ 347.5
3.7% notes payable, due 2029
Long-Term Debt
Interest rate (as a percent)	3.70%	3.70%
Long-term debt principal	$ 500	$ 500
Net unamortized discount, premium and debt issuance costs	(5.5)	(6.1)
Long-term debt carrying amount	$ 494.5	$ 493.9
2.125% notes payable, due 2030
Long-Term Debt
Interest rate (as a percent)	2.125%
Long-term debt principal	$ 600
Net unamortized discount, premium and debt issuance costs	(4.6)
Long-term debt carrying amount	$ 595.4
6.05% notes payable, due 2036
Long-Term Debt
Interest rate (as a percent)	6.05%	6.05%
Long-term debt principal	$ 505.6	$ 505.6
Net unamortized discount, premium and debt issuance costs	(2.5)	(2.4)
Long-term debt carrying amount	$ 503.1	$ 503.2
4.625% notes payable, due 2042
Long-Term Debt
Interest rate (as a percent)	4.625%	4.625%
Long-term debt principal	$ 300	$ 300
Net unamortized discount, premium and debt issuance costs	(3.1)	(3.2)
Long-term debt carrying amount	$ 296.9	$ 296.8
4.35% notes payable, due 2043
Long-Term Debt
Interest rate (as a percent)	4.35%	4.35%
Long-term debt principal	$ 300	$ 300
Net unamortized discount, premium and debt issuance costs	(3.1)	(3.3)
Long-term debt carrying amount	$ 296.9	$ 296.7
4.3% notes payable, due 2046
Long-Term Debt
Interest rate (as a percent)	4.30%	4.30%
Long-term debt principal	$ 300	$ 300
Net unamortized discount, premium and debt issuance costs	(3.2)	(3.3)
Long-term debt carrying amount	296.8	$ 296.7
4.7% notes payable, due 2055
Long-Term Debt
Interest rate (as a percent)		4.70%
Long-term debt principal		$ 400
Net unamortized discount, premium and debt issuance costs		(4.9)
Long-term debt carrying amount		395.1
Floating rate notes payable, due 2055
Long-Term Debt
Long-term debt principal	400
Net unamortized discount, premium and debt issuance costs	(4.7)
Long-term debt carrying amount	395.3
Non-recourse mortgages and notes payable
Long-Term Debt
Long-term debt principal	55.5	107.6
Net unamortized discount, premium and debt issuance costs	0.5	1.2
Long-term debt carrying amount	$ 56	$ 108.8

Debt - Senior Notes and Junior

Debt - Senior Notes and Junior Subordinated Notes (Details) - USD ($) $ in Millions

May 07, 2015

Sep. 05, 2012

Aug. 15, 2009

Dec. 31, 2016

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Aug. 03, 2020

Jun. 12, 2020

May 07, 2019

Nov. 10, 2016

Nov. 16, 2012

May 18, 2009

Dec. 05, 2006

Oct. 16, 2006

Long-Term Debt

Principal repayments of long-term debt

$ 65.8

$ 32.2

$ 1.3

Maximum | Junior subordinated notes

Long-Term Debt

Years interest payments on debt can be deferred

5 years

3.1% notes payable, due 2026 and 4.3% notes payable, due 2046 | Senior notes

Long-Term Debt

Long-term debt issued

$ 650

3.1% notes payable, due 2026

Long-Term Debt

Interest rate (as a percent)

3.10%

3.10%

3.1% notes payable, due 2026 | Senior notes

Long-Term Debt

Long-term debt issued

$ 350

Interest rate (as a percent)

3.10%

4.3% notes payable, due 2046

Long-Term Debt

Interest rate (as a percent)

4.30%

4.30%

4.3% notes payable, due 2046 | Senior notes

Long-Term Debt

Long-term debt issued

$ 300

Interest rate (as a percent)

4.30%

3.4% notes payable, due 2025

Long-Term Debt

Interest rate (as a percent)

3.40%

3.40%

3.4% notes payable, due 2025 | Senior notes

Long-Term Debt

Long-term debt issued

$ 400

Interest rate (as a percent)

3.40%

4.7% notes payable, due 2055

Long-Term Debt

Interest rate (as a percent)

4.70%

4.7% notes payable, due 2055 | Junior subordinated notes

Long-Term Debt

Long-term debt issued

$ 400

Interest rate (as a percent)

4.70%

Reference rate for floating rate of debt instrument

3-month LIBOR

Spread added to floating reference interest rate (as a percent)

3.044%

1.85% notes payable, due 2017; 3.125% notes payable, due 2023; and 4.35% notes payable, due 2043 | Senior notes

Long-Term Debt

Long-term debt issued

$ 900

1.85% notes payable, due 2017 | Senior notes

Long-Term Debt

Long-term debt issued

$ 300

Interest rate (as a percent)

1.85%

3.125% notes payable, due 2023

Long-Term Debt

Interest rate (as a percent)

3.125%

3.125%

3.125% notes payable, due 2023 | Senior notes

Long-Term Debt

Long-term debt issued

$ 300

Interest rate (as a percent)

3.125%

4.35% notes payable, due 2043

Long-Term Debt

Interest rate (as a percent)

4.35%

4.35%

4.35% notes payable, due 2043 | Senior notes

Long-Term Debt

Long-term debt issued

$ 300

Interest rate (as a percent)

4.35%

3.3% notes payable, due 2022 and 4.625% notes payable, due 2042 | Senior notes

Long-Term Debt

Long-term debt issued

$ 600

3.3% notes payable, due 2022

Long-Term Debt

Interest rate (as a percent)

3.30%

3.30%

3.3% notes payable, due 2022 | Senior notes

Long-Term Debt

Long-term debt issued

$ 300

Interest rate (as a percent)

3.30%

4.625% notes payable, due 2042

Long-Term Debt

Interest rate (as a percent)

4.625%

4.625%

4.625% notes payable, due 2042 | Senior notes

Long-Term Debt

Long-term debt issued

$ 300

Interest rate (as a percent)

4.625%

7.875% notes payable, due 2014 and 8.875% notes payable, due 2019 | Senior notes

Long-Term Debt

Long-term debt issued

$ 750

7.875% notes payable, due 2014 | Senior notes

Long-Term Debt

Long-term debt issued

$ 400

Interest rate (as a percent)

7.875%

Principal repayments of long-term debt

$ 400

8.875% notes payable, due 2019 | Senior notes

Long-Term Debt

Long-term debt issued

$ 350

Interest rate (as a percent)

8.875%

8.2% notes payable, due 2009 | Senior notes

Long-Term Debt

Principal repayments of long-term debt

$ 440.9

6.05% notes payable, due 2036

Long-Term Debt

Interest rate (as a percent)

6.05%

6.05%

6.05% notes payable, due 2036 | Senior notes

Long-Term Debt

Principal repayments of long-term debt

$ 94.4

6.05% notes payable, due 2036, issued in October 2006 | Senior notes

Long-Term Debt

Long-term debt issued

$ 500

Interest rate (as a percent)

6.05%

6.05% notes payable, due 2036, issued in December 2006 | Senior notes

Long-Term Debt

Long-term debt issued

$ 100

Interest rate (as a percent)

6.05%

3.7% notes payable, due 2029

Long-Term Debt

Interest rate (as a percent)

3.70%

3.70%

3.7% notes payable, due 2029 | Senior notes

Long-Term Debt

Long-term debt issued

$ 500

Interest rate (as a percent)

3.70%

2.125% notes payable, due 2030

Long-Term Debt

Interest rate (as a percent)

2.125%

2.125% notes payable, due 2030 | Senior notes

Long-Term Debt

Long-term debt issued

$ 100

$ 500

Interest rate (as a percent)

2.125%

2.125%

Debt - Non-Recourse Mortgages a

Debt - Non-Recourse Mortgages and Notes Payable (Details) - Non-recourse mortgages and notes payable - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Long-Term Debt
Outstanding principal balances per real estate development, low end of range	$ 3.1	$ 3.7
Outstanding principal balances per real estate development, high end of range	15.1	64.2
Real estate	$ 194.1	$ 238.2
Minimum
Long-Term Debt
Interest rate (as a percent)	3.50%	3.90%
Maximum
Long-Term Debt
Interest rate (as a percent)	4.80%	4.80%

Debt - Future Maturities of Lon

Debt - Future Maturities of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Future maturities of long-term debt
Year 1: Long-term debt maturities	$ 2
Year 2: Long-term debt maturities	301.4
Year 3: Long-term debt maturities	323.8
Year 4: Long-term debt maturities	17.5
Year 5: Long-term debt maturities	398.2
Year 6 and thereafter: Long-term debt maturities	3,236.3
Long-term debt carrying amount	$ 4,279.2	$ 3,734.1

Debt - Contingent Funding Agree

Debt - Contingent Funding Agreements (Details) $ in Millions	Mar. 08, 2018USD ($)item
Contingent funding agreements
Long-Term Debt
Number of contingent funding agreements | item	2
Period failure to make payments to trust can be cured before automatic exercise of put options	30 days
Minimum shareholders' equity excluding AOCI and NCI, to avoid automatic exercise of options	$ 4,000
10-year contingent funding agreement | 2028 Trust
Long-Term Debt
Term of contingent funding agreement	10 years
Semi-annual put premium (as a percent)	1.275%
10-year contingent funding agreement | 2028 Trust | Senior Notes due 2028
Long-Term Debt
Amount of notes issuable under option	$ 400
Interest rate (as a percent)	4.111%
30-year contingent funding agreement | 2048 Trust
Long-Term Debt
Term of contingent funding agreement	30 years
Annual put premium (as a percent)	1.58%
30-year contingent funding agreement | 2048 Trust | Senior Notes due 2048
Long-Term Debt
Amount of notes issuable under option	$ 350
Interest rate (as a percent)	4.682%
2028 Trust
Long-Term Debt
Pre-capitalized trust securities sold	$ 400
2048 Trust
Long-Term Debt
Pre-capitalized trust securities sold	$ 350

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense and Income Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Current income taxes (benefits): U.S. federal	$ 15.8	$ 31.9	$ (48.9)
Current income taxes (benefits): State	5	18.1	10.3
Current income taxes (benefits): Foreign	55.4	45.6	51.7
Current income taxes (benefits): Tax benefit of operating loss carryforwards	(3.3)	(3)	(13.5)
Total current income taxes (benefits)	72.9	92.6	(0.4)
Deferred income taxes (benefits): U.S. federal	143.6	108.6	224.3
Deferred income taxes (benefits): State	11.5	6.9	19.2
Deferred income taxes (benefits): Foreign	37	41.1	(12.4)
Total deferred income taxes (benefits)	192.1	156.6	231.1
Income taxes (benefits)	265	249.2	230.7
Income (loss) before income taxes
Income (loss) before income taxes - domestic	1,323.2	1,351.9	1,661.1
Income (loss) before income taxes - foreign	370.3	341.4	123.3
Income (loss) before income taxes	$ 1,693.5	$ 1,693.3	$ 1,784.4

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation between the U.S. corporate income tax rate and the effective income tax rate from continuing operations
U.S. corporate income tax rate (as a percent)	21.00%	21.00%	21.00%
Dividends received deduction (as a percent)	(4.00%)	(5.00%)	(4.00%)
Tax credits (as a percent)	(3.00%)	(3.00%)	(3.00%)
Impact of equity method presentation (as a percent)	(1.00%)	(2.00%)	(1.00%)
Interest exclusion from taxable income (as a percent)	(1.00%)		(1.00%)
Impact of the Tax Cuts and Jobs Act (as a percent)			(3.00%)
State income taxes (as a percent)	1.00%	1.00%	1.00%
Local country permanent tax adjustments (as a percent)		1.00%	1.00%
Other income tax rate impacts (as a percent)	3.00%	2.00%	2.00%
Effective income tax rate (as a percent)	16.00%	15.00%	13.00%

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Changes in Unrecognized Tax Benefits
Beginning balance, Unrecognized tax benefits	$ 61.6	$ 42.1	$ 194.1
Additions based on tax positions related to the current year	1.3	0.1	0.8
Additions for tax positions of prior years	17.4	23.1	43.7
Reductions for tax positions related to the current year	(3.2)	(3.2)	(10.6)
Reductions for tax positions of prior years		(0.5)	(23.2)
Settlements	(14.5)		(162.7)
Expired statute of limitations	(15.7)
Ending balance, Unrecognized tax benefits	46.9	61.6	42.1
Amount of unrecognized tax benefits that would reduce the effective income tax rate, if recognized	1.1
Accumulated pre-tax interest and penalties related to unrecognized tax benefits	$ 1.1	$ 0.9	$ 1.6

Income Taxes - Deferred Income

Income Taxes - Deferred Income Taxes and Other (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2020
Deferred income tax assets:
Investments, including derivative liabilities	$ 237			$ 588.4
Insurance liabilities	143.2			552.4
Net operating and capital loss carryforwards	71.1			69.2
Tax credit carryforwards	106			4.6
Employee benefits	338.9			389.1
Foreign currency translation	14			9.7
Other deferred income tax assets	45.2			52.5
Gross deferred income tax assets	955.4			1,665.9
Valuation allowance	(16.7)			(18.4)
Total deferred income tax assets	938.7			1,647.5
Deferred income tax liabilities:
Deferred income tax liabilities: Deferred acquisition costs	(562.9)			(522.6)
Investments, including derivative assets	(443.7)			(990.4)
Net unrealized gains on available-for-sale securities	(1,039.9)			(1,762.1)
Deferred income tax liabilities: Real estate	(147.9)			(158.5)
Intangible assets	(342.3)			(387.5)
Other deferred income tax liabilities	(75)			(43.4)
Total deferred income tax liabilities	(2,611.7)			(3,864.5)
Total net deferred income tax liabilities	(1,673)			(2,217)
Net deferred income taxes by jurisdiction
Net deferred income tax assets	123.6			113.8
Net deferred income tax liabilities	(1,796.6)			(2,330.8)
Total net deferred income tax liabilities	(1,673)			(2,217)
Deferred income tax disclosures
Provisional amount of deemed repatriation tax			$ 43
Adjustments to deferred tax assets and liabilities	11.1
Adjustment to one-time deemed repatriation tax		$ 5.9
One-time deemed repatriation tax, final determination amount		$ 48.9
Accumulated but undistributed earnings from operations of foreign subsidiaries for which U.S. federal and state deferred income taxes have not been provided	1,001.5			997.4
Excess book carrying value over tax basis with respect to the original investment of foreign subsidiaries for which U.S. federal and state deferred income taxes have not been provided				106.2
Current income tax receivables associated with outstanding audit issues
Current income tax (receivables) payables associated with outstanding audit issues	(195.3)			(54.6)
U.S. Federal
Deferred income tax assets:
Tax credit carryforwards	106			4.6
Net deferred income taxes by jurisdiction
Net deferred income tax liabilities	(1,507.6)			(2,011.8)
State
Net deferred income taxes by jurisdiction
Net deferred income tax assets	94.9			81.1
Deferred income tax disclosures-operating loss carryforwards
Net operating loss carryforwards	190.4			269.5
Foreign
Net deferred income taxes by jurisdiction
Net deferred income tax assets	28.7			32.7
Net deferred income tax liabilities	(289)			(319)
Deferred income tax disclosures-operating loss carryforwards
Net operating loss carryforwards	186.1			170.3
Valuation allowances on income tax benefits primarily associated with foreign net operating loss carryforwards	$ 16.7			$ 18.4

Employee and Agent Benefits - P

Employee and Agent Benefits - Plan Information (Details)	12 Months Ended
	Dec. 31, 2020
Pension benefits
Defined Benefit Plan Disclosures
Period of employment used to calculate average annual compensation for the final average pay benefit	5 years

Employee and Agent Benefits - B

Employee and Agent Benefits - Benefit Obligation and Funded Status (Details) - USD ($) $ in Millions	May 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension benefits
Change in benefit obligation
Benefit obligation at beginning of year		$ (3,692.1)	$ (3,239.2)
Service cost		(72.7)	(66)	$ (73)
Interest cost		(117.3)	(126.5)	(119.5)
Actuarial gain (loss)	$ (59)	(462.4)	(506.4)
Benefits paid		134.3	123.6
Plan amendments			122.4
Benefit obligation at end of year		(4,210.2)	(3,692.1)	(3,239.2)
Change in plan assets
Fair value of plan assets at beginning of year		2,926	2,498.2
Actual return on plan assets	$ 178.6	521.3	520.9
Employer contribution		60.5	30.5
Benefits paid		(134.3)	(123.6)
Fair value of plan assets at end of year		3,373.5	2,926	2,498.2
Amount recognized in statement of financial position
Amount recognized in other liabilities		(836.7)	(766.1)
Total assets (liabilities) recognized in statement of financial position		(836.7)	(766.1)
Amount recognized in accumulated other comprehensive (income) loss
Total net actuarial (gain) loss		760	737.5
Prior service (benefit) cost		(121)	(137.8)
Pre-tax accumulated other comprehensive (income) loss		639	599.7
Additional defined benefit plan disclosures
Accumulated benefit obligation		4,136.5	3,599.5
Market value of assets held in Rabbi trusts for benefit of nonqualified pension plan participants		394.8	377.8
Other postretirement benefits
Change in benefit obligation
Benefit obligation at beginning of year		(101.4)	(98.9)
Service cost				(0.1)
Interest cost		(2.8)	(3.7)	(3.5)
Actuarial gain (loss)		(11.7)	(4.8)
Participant contributions		(6)	(4.4)
Benefits paid		12.8	12.2
Plan amendments		1	(1.8)
Other		0.1
Benefit obligation at end of year		(108)	(101.4)	(98.9)
Change in plan assets
Fair value of plan assets at beginning of year		732.8	643.9
Actual return on plan assets		53.1	95.5
Employer contribution		1.5	1.2
Participant contributions		6	4.4
Benefits paid		(12.8)	(12.2)
Fair value of plan assets at end of year		780.6	732.8	$ 643.9
Amount recognized in statement of financial position
Amount recognized in other assets		675.5	635.1
Amount recognized in other liabilities		(2.9)	(3.7)
Total assets (liabilities) recognized in statement of financial position		672.6	631.4
Amount recognized in accumulated other comprehensive (income) loss
Total net actuarial (gain) loss		(22.8)	(17.4)
Prior service (benefit) cost		(7.3)	(7.3)
Pre-tax accumulated other comprehensive (income) loss		$ (30.1)	$ (24.7)

Employee and Agent Benefits -_2

Employee and Agent Benefits - Pension Plan Changes and Plan Gains/Losses (Details) - Pension benefits - USD ($) $ in Millions	May 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Components of Net Periodic Benefit Cost (Income)
Actuarial gain (loss)	$ (59)	$ (462.4)	$ (506.4)
Total plan amendment gain	122.4
Increase in benefit obligation	237.6
Asset gain on plan assets	$ 178.6	$ 521.3	$ 520.9

Employee and Agent Benefits - O

Employee and Agent Benefits - Other Postretirement Plan Changes and Plan Gains/Losses (Details) - Other postretirement benefits $ in Millions	Jan. 01, 2021USD ($)
Defined Benefit Plan Disclosures
Amount of assets in excess of expected liability for retirees, re-designated for non-retiree benefits	$ 655.5
Percentage of assets in excess of expected liabilities to fund other benefits covered under the plans	125.00%

Employee and Agent Benefits - A

Employee and Agent Benefits - ABO in Excess of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension benefits
Information for Defined Benefit Plans With an Accumulated Benefit Obligation in Excess of Plan Assets
Projected benefit obligation for defined benefit plans with an accumulated benefit obligation in excess of plan assets	$ 4,210.2	$ 3,692.1
Accumulated benefit obligation for defined benefit plans with an accumulated benefit obligation in excess of plan assets	4,136.5	3,599.5
Fair value of plan assets for defined benefit plans with an accumulated benefit obligation in excess of plan assets	3,373.5	2,926
Other postretirement benefits
Information for Defined Benefit Plans With an Accumulated Benefit Obligation in Excess of Plan Assets
Accumulated benefit obligation for defined benefit plans with an accumulated benefit obligation in excess of plan assets	$ 2.9	$ 3.8

Employee and Agent Benefits - N

Employee and Agent Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Plan actuarial gain and loss amortization disclosures
Allowable corridor not used for amortization of actuarial gains and losses of qualified pension plan (as a percent)	10.00%
Pension benefits
Components of Net Periodic Benefit Cost (Income)
Service cost	$ 72.7	$ 66	$ 73
Interest cost	$ 117.3	$ 126.5	$ 119.5
Interest cost, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Expected return on plan assets	$ (156.8)	$ (148.8)	$ (157)
Expected return on plan assets, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Amortization of prior service (benefit) cost	$ (16.8)	$ (11.3)	$ (3.4)
Amortization of prior service (benefit) cost, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Recognized net actuarial (gain) loss	$ 75.4	$ 70.1	$ 67.8
Recognized net actuarial (gain) loss, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Net periodic benefit cost (income)	$ 91.8	$ 102.5	$ 99.9
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	97.9	134.3
Prior service (benefit) cost		(122.4)
Amortization of net gain (loss)	(75.4)	(70.1)
Amortization of prior service benefit (cost)	16.8	11.3
Total recognized in pre-tax accumulated other comprehensive (income) loss	39.3	(46.9)
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	131.1	55.6
Other postretirement benefits
Components of Net Periodic Benefit Cost (Income)
Service cost			0.1
Interest cost	$ 2.8	$ 3.7	$ 3.5
Interest cost, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Expected return on plan assets	$ (36)	$ (33.2)	$ (33.6)
Expected return on plan assets, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Amortization of prior service (benefit) cost	$ (1)	$ (1.2)	$ (13.9)
Amortization of prior service (benefit) cost, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Recognized net actuarial (gain) loss		$ 0.1	$ (1.5)
Recognized net actuarial (gain) loss, location on consolidated statements of operations	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization	pfg:OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization
Net periodic benefit cost (income)	$ (34.2)	$ (30.6)	$ (45.4)
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	(5.4)	(57.5)
Prior service (benefit) cost	(1)	1.7
Amortization of net gain (loss)		(0.1)
Amortization of prior service benefit (cost)	1	1.2
Total recognized in pre-tax accumulated other comprehensive (income) loss	(5.4)	(54.7)
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	$ (39.6)	$ (85.3)

Employee and Agent Benefits - W

Employee and Agent Benefits - Weighted Average Assumptions (Details)	3 Months Ended	5 Months Ended	7 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2020	May 31, 2019	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension benefits
Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section
Discount rate: Benefit obligation (as a percent)			3.25%	2.50%	2.50%	3.25%
Interest crediting rate - cash balance benefit				5.00%	5.00%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate: Net periodic benefit cost (as a percent)		4.15%	3.70%		3.25%	3.70%	3.60%
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)					5.60%	5.95%	6.30%
Interest crediting rate - cash balance benefit					5.00%
Pension benefits, Cash balance benefit
Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section
Rate of compensation increase: Benefit obligation (as a percent)			4.95%	4.92%	4.92%	4.95%
Weighted-average assumptions used to determine net periodic benefit cost
Rate of compensation increase: Net periodic benefit cost (as a percent)					4.95%	4.94%	4.96%
Pension benefits, Traditional benefit
Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section
Rate of compensation increase: Benefit obligation (as a percent)			2.98%	2.96%	2.96%	2.98%
Weighted-average assumptions used to determine net periodic benefit cost
Rate of compensation increase: Net periodic benefit cost (as a percent)					2.98%	2.73%	2.77%
Other postretirement benefits
Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section
Discount rate: Benefit obligation (as a percent)			2.95%	2.10%	2.10%	2.95%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate: Net periodic benefit cost (as a percent)	2.95%			2.90%	2.95%	3.95%	3.35%
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)					4.94%	5.19%	4.85%
Rate of compensation increase: Net periodic benefit cost (as a percent)							2.39%
Subsidy increase cap allowed per calendar year (as a percent)	5.00%
Assumed Health Care Cost Trend Rates
Health care cost trend rate assumed for next year under age 65 (as a percent)			6.75%	6.75%	6.75%	6.75%
Health care cost trend rate assumed for next year age 65 and over (as a percent)			6.00%	6.00%	6.00%	6.00%
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate) (as a percent)			4.50%	4.50%	4.50%	4.50%
Year that the health care cost trend rate reaches the ultimate trend rate under age 65 (calendar year)					2029	2028
Year that the health care cost trend rate reaches the ultimate trend rate age 65 and over (calendar year)					2026	2025
Home office medical and life plans
Weighted-average assumptions used to determine net periodic benefit cost
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)					5.00%
Agent medical and life plans
Weighted-average assumptions used to determine net periodic benefit cost
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)					4.70%
Post-65 medical plans
Weighted-average assumptions used to determine net periodic benefit cost
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)					4.70%

Employee and Agent Benefits - F

Employee and Agent Benefits - Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension benefits
Defined benefit plan, fair value of plan assets
Fair value of plan assets	$ 3,373.5	$ 2,926	$ 2,498.2
Pension benefits | Qualified benefit plans
Defined benefit plan, fair value of plan assets
Fair value of plan assets	3,373.5	2,926
Pension benefits | Qualified benefit plans | Pooled separate account investments | U.S. large cap equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	712.2	509.7
Pension benefits | Qualified benefit plans | Pooled separate account investments | U.S. small/mid cap equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	121.6	90.9
Pension benefits | Qualified benefit plans | Pooled separate account investments | Balanced asset allocation portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	103.7	78.5
Pension benefits | Qualified benefit plans | Pooled separate account investments | International equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	459.6	328.6
Pension benefits | Qualified benefit plans | Pooled separate account investments | Real estate investment portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	195.1	193.5
Pension benefits | Qualified benefit plans | Single client separate account investments | U.S. government and agencies
Defined benefit plan, fair value of plan assets
Fair value of plan assets	297.5	485.9
Pension benefits | Qualified benefit plans | Single client separate account investments | States and political subdivisions
Defined benefit plan, fair value of plan assets
Fair value of plan assets	28	26.1
Pension benefits | Qualified benefit plans | Single client separate account investments | Corporate debt securities
Defined benefit plan, fair value of plan assets
Fair value of plan assets	1,223.1	1,009.1
Pension benefits | Qualified benefit plans | Single client separate account investments | Commercial mortgage-backed securities
Defined benefit plan, fair value of plan assets
Fair value of plan assets	13.6	32.7
Pension benefits | Qualified benefit plans | Single client separate account investments | Other debt obligations
Defined benefit plan, fair value of plan assets
Fair value of plan assets	6.4	7.1
Pension benefits | Qualified benefit plans | Single client separate account investments | Hedge funds
Defined benefit plan, fair value of plan assets
Fair value of plan assets	155.8	129
Pension benefits | Qualified benefit plans | Single client separate account investments | Pooled separate account investment
Defined benefit plan, fair value of plan assets
Fair value of plan assets	55.1	31.5
Pension benefits | Qualified benefit plans | Single client separate account investments | Other
Defined benefit plan, fair value of plan assets
Fair value of plan assets	1.8	3.4
Pension benefits | Qualified benefit plans | Amount measured at net asset value
Defined benefit plan, fair value of plan assets
Fair value of plan assets	155.8	129
Pension benefits | Qualified benefit plans | 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	155.8	129
Pension benefits | Qualified benefit plans | Fair value hierarchy Level 1
Defined benefit plan, fair value of plan assets
Fair value of plan assets	297.5	485.9
Pension benefits | Qualified benefit plans | 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	297.5	485.9
Pension benefits | Qualified benefit plans | Fair value hierarchy Level 2
Defined benefit plan, fair value of plan assets
Fair value of plan assets	2,920.2	2,311.1
Pension benefits | Qualified benefit plans | 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	712.2	509.7
Pension benefits | Qualified benefit plans | 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	121.6	90.9
Pension benefits | Qualified benefit plans | 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	103.7	78.5
Pension benefits | Qualified benefit plans | 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	459.6	328.6
Pension benefits | Qualified benefit plans | 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	195.1	193.5
Pension benefits | Qualified benefit plans | 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	28	26.1
Pension benefits | Qualified benefit plans | 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	1,223.1	1,009.1
Pension benefits | Qualified benefit plans | 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	13.6	32.7
Pension benefits | Qualified benefit plans | 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	6.4	7.1
Pension benefits | Qualified benefit plans | 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	55.1	31.5
Pension benefits | Qualified benefit plans | Fair value hierarchy Level 2 | Single client separate account investments | Other
Defined benefit plan, fair value of plan assets
Fair value of plan assets	1.8	3.4
Other postretirement benefits
Defined benefit plan, fair value of plan assets
Fair value of plan assets	780.6	732.8	$ 643.9
Fair value of plan assets included in trust owned life insurance contract	117.6	101.8
Other postretirement benefits | Cash and cash equivalents
Defined benefit plan, fair value of plan assets
Fair value of plan assets	0.5	0.6
Other postretirement benefits | Fixed income investment funds
Defined benefit plan, fair value of plan assets
Fair value of plan assets	625.2	370.5
Other postretirement benefits | U.S. equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	103.5	254.5
Other postretirement benefits | International equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	51.4	107.2
Other postretirement benefits | Fair value hierarchy Level 1
Defined benefit plan, fair value of plan assets
Fair value of plan assets	663	630.8
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	0.5	0.6
Other postretirement benefits | Fair value hierarchy Level 1 | Fixed income investment funds
Defined benefit plan, fair value of plan assets
Fair value of plan assets	605.9	331
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	38.2	210.3
Other postretirement benefits | Fair value hierarchy Level 1 | International equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	18.4	88.9
Other postretirement benefits | Fair value hierarchy Level 2
Defined benefit plan, fair value of plan assets
Fair value of plan assets	117.6	102
Other postretirement benefits | Fair value hierarchy Level 2 | Fixed income investment funds
Defined benefit plan, fair value of plan assets
Fair value of plan assets	19.3	39.5
Other postretirement benefits | Fair value hierarchy Level 2 | U.S. equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	65.3	44.2
Other postretirement benefits | Fair value hierarchy Level 2 | International equity portfolios
Defined benefit plan, fair value of plan assets
Fair value of plan assets	$ 33	$ 18.3

Employee and Agent Benefits - T

Employee and Agent Benefits - Target Plan Asset Allocation (Details)	Dec. 31, 2020
Pension benefits | Qualified benefit plans | Fixed income security portfolios | Minimum
Asset category target allocation
Asset category target allocation	25.00%
Pension benefits | Qualified benefit plans | Fixed income security portfolios | Maximum
Asset category target allocation
Asset category target allocation	80.00%
Pension benefits | Qualified benefit plans | Equity portfolios | Minimum
Asset category target allocation
Asset category target allocation	5.00%
Pension benefits | Qualified benefit plans | Equity portfolios | Maximum
Asset category target allocation
Asset category target allocation	60.00%
Pension benefits | Qualified benefit plans | Real estate investment portfolios
Asset category target allocation
Asset category target allocation	10.00%
Pension benefits | Qualified benefit plans | Alternatives
Asset category target allocation
Asset category target allocation	5.00%
Other postretirement benefits | U.S. equity portfolios
Asset category target allocation
Asset category target allocation	35.00%
Other postretirement benefits | International equity portfolios
Asset category target allocation
Asset category target allocation	15.00%
Other postretirement benefits | Fixed income security portfolios
Asset category target allocation
Asset category target allocation	50.00%

Employee and Agent Benefits - C

Employee and Agent Benefits - Contributions and Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2020USD ($)
Pension benefits
Estimated Future Benefit Payments
Estimated future benefit payments, Year 1	$ 160.2
Estimated future benefit payments, Year 2	159.9
Estimated future benefit payments, Year 3	166.6
Estimated future benefit payments, Year 4	175.8
Estimated future benefit payments, Year 5	179.3
Estimated future benefit payments, Years 6-10	1,026
Pension benefits | Maximum
Contributions
Possible contributions to be made during the next fiscal year to the qualified and nonqualified pension plans combined	100
Other postretirement benefits
Estimated Future Benefit Payments
Estimated future benefit payments, Year 1	15.5
Estimated future benefit payments, Year 2	14.8
Estimated future benefit payments, Year 3	13.5
Estimated future benefit payments, Year 4	12.2
Estimated future benefit payments, Year 5	10.9
Estimated future benefit payments, Years 6-10	$ 38.3

Employee and Agent Benefits - S

Employee and Agent Benefits - Supplemental Information, Qualified and Nonqualified Plans (Details) - Pension benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amount recognized in statement of financial position
Amount recognized in other liabilities	$ (836.7)	$ (766.1)
Total assets (liabilities) recognized in statement of financial position	(836.7)	(766.1)
Amount recognized in accumulated other comprehensive (income) loss
Total net actuarial (gain) loss	760	737.5
Prior service (benefit) cost	(121)	(137.8)
Pre-tax accumulated other comprehensive (income) loss	639	599.7
Components of Net Periodic Benefit Cost (Income)
Service cost	72.7	66	$ 73
Interest cost	117.3	126.5	119.5
Expected return on plan assets	(156.8)	(148.8)	(157)
Amortization of prior service (benefit) cost	(16.8)	(11.3)	(3.4)
Recognized net actuarial (gain) loss	75.4	70.1	67.8
Net periodic benefit cost (income)	91.8	102.5	$ 99.9
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	97.9	134.3
Prior service (benefit) cost		(122.4)
Amortization of net gain (loss)	(75.4)	(70.1)
Amortization of prior service benefit (cost)	16.8	11.3
Total recognized in pre-tax accumulated other comprehensive (income) loss	39.3	(46.9)
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	131.1	55.6
Qualified benefit plans
Amount recognized in statement of financial position
Amount recognized in other liabilities	(294.9)	(258.7)
Total assets (liabilities) recognized in statement of financial position	(294.9)	(258.7)
Amount recognized in accumulated other comprehensive (income) loss
Total net actuarial (gain) loss	563.5	567.6
Prior service (benefit) cost	(97.8)	(110.3)
Pre-tax accumulated other comprehensive (income) loss	465.7	457.3
Components of Net Periodic Benefit Cost (Income)
Service cost	66.1	59.7
Interest cost	101.2	108
Expected return on plan assets	(156.8)	(148.8)
Amortization of prior service (benefit) cost	(12.6)	(7.8)
Recognized net actuarial (gain) loss	59.9	57.6
Net periodic benefit cost (income)	57.8	68.7
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	55.7	80.8
Prior service (benefit) cost		(107.2)
Amortization of net gain (loss)	(59.8)	(57.6)
Amortization of prior service benefit (cost)	12.6	7.8
Total recognized in pre-tax accumulated other comprehensive (income) loss	8.5	(76.2)
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	66.3	(7.5)
Nonqualified benefit plans
Amount recognized in statement of financial position
Amount recognized in other liabilities	(541.8)	(507.4)
Total assets (liabilities) recognized in statement of financial position	(541.8)	(507.4)
Amount recognized in accumulated other comprehensive (income) loss
Total net actuarial (gain) loss	196.5	169.9
Prior service (benefit) cost	(23.2)	(27.5)
Pre-tax accumulated other comprehensive (income) loss	173.3	142.4
Components of Net Periodic Benefit Cost (Income)
Service cost	6.6	6.3
Interest cost	16.1	18.5
Amortization of prior service (benefit) cost	(4.2)	(3.5)
Recognized net actuarial (gain) loss	15.5	12.5
Net periodic benefit cost (income)	34	33.8
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	42.2	53.5
Prior service (benefit) cost		(15.2)
Amortization of net gain (loss)	(15.6)	(12.5)
Amortization of prior service benefit (cost)	4.2	3.5
Total recognized in pre-tax accumulated other comprehensive (income) loss	30.8	29.3
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	$ 64.8	$ 63.1

Employee and Agent Benefits - D

Employee and Agent Benefits - Defined Contribution and Deferred Compensation Plans (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosures
Number of common stock shares allocated participants in the employee stock ownership plan	2.3	2.2
Fair value of employee stock ownership plan	$ 115,100,000	$ 119,800,000
Pension benefits | Qualified benefit plans
Defined Contribution Plan Disclosures
Maximum amount of compensation eligible participants could contribute to defined contribution plans	19,500
Amount contributed by the employer to defined contribution plans	56,700,000	55,300,000	$ 53,400,000
Pension benefits | Nonqualified benefit plans
Defined Contribution Plan Disclosures
Amount contributed by the employer to defined contribution plans	$ 3,100,000	$ 3,200,000	$ 3,400,000
Defined contribution pension benefits - Grandfathered Choice Participant | Qualified benefit plans
Defined Contribution Plan Disclosures
Eligibility age to be able to elect to retain benefits in defined contribution plan	47 years
Minimum years of service to be able to elect to retain benefits in defined contribution plan	10 years
Contribution rate of employer to match participant's contributions (as a percent)	50.00%
Maximum percent of participant's compensation matched by employer (as a percent)	3.00%
Defined contribution pension benefits - Grandfathered Choice Participant | Nonqualified benefit plans
Defined Contribution Plan Disclosures
Contribution rate of employer to match participant's contributions (as a percent)	50.00%
Maximum percent of participant's compensation matched by employer (as a percent)	3.00%
Defined contribution pension benefits - All other participants | Qualified benefit plans
Defined Contribution Plan Disclosures
Contribution rate of employer to match participant's contributions (as a percent)	75.00%
Maximum percent of participant's compensation matched by employer (as a percent)	6.00%
Defined contribution pension benefits - All other participants | Nonqualified benefit plans
Defined Contribution Plan Disclosures
Contribution rate of employer to match participant's contributions (as a percent)	75.00%
Maximum percent of participant's compensation matched by employer (as a percent)	6.00%

Contingencies, Guarantees, In_3

Contingencies, Guarantees, Indemnifications and Leases - Guarantees and Indemnifications (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Guaranty Funds
Undiscounted liability balance for guaranty fund assessments	$ 21.1	$ 21.7
Premium tax offsets	9.6	$ 10
Guarantees to third parties primarily related to former subsidiaries and joint ventures
Guarantees and Indemnifications
Maximum exposure under guarantees	121
Guarantees related to P-Caps contingent funding agreements
Guarantees and Indemnifications
Maximum exposure under guarantees	750
Lawsuit alleging breach of fiduciary duty related to PFIO
Loss contingencies - disclosures
Estimated losses accrued related to legal matters	$ 0

Contingencies, Guarantees, In_4

Contingencies, Guarantees, Indemnifications and Leases - Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Operating lease assets	$ 234.9	$ 190
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Finance lease assets	$ 49.5	$ 31.4
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Total lease assets	$ 284.4	$ 221.4
Liabilities
Operating lease liabilities	$ 231.4	$ 197.5
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities	Other Liabilities
Finance lease liabilities	$ 50.1	$ 31.8
Finance Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities	Other Liabilities
Total lease liabilities	$ 281.5	$ 229.3
Finance lease cost:
Amortization of right-of-use assets	20.5	14.6
Interest on lease liabilities	1	1
Operating lease cost	58.7	55.8
Other lease cost	8.6	8
Sublease income	(1.6)	(1.7)
Total lease cost	87.2	77.7
Operating lease rental expense			$ 36.7
Capital lease depreciation expense			$ 12.9
Payments for operating leases	71.6	56.1
Payments for finance leases	21.2	15.1
Operating leases, payments due for the twelve months ending December 31:
2021	56.9
2022	49.8
2023	39.1
2024	30.5
2025	22.8
2026 and thereafter	60.8
Total lease payments	259.9
Less: interest	28.5
Present value of lease liabilities	231.4	197.5
Finance leases, payments due for the twelve months ending December 31:
2021	21.5
2022	13.6
2023	11.4
2024	3.6
2025	1.2
Total lease payments	51.3
Less: interest	1.2
Present value of lease liabilities	50.1	31.8
Total leases, payments due for the twelve months ending December 31:
2021	78.4
2022	63.4
2023	50.5
2024	34.1
2025	24
2026 and thereafter	60.8
Total lease payments	311.2
Less: interest	29.7
Present value of lease liabilities	$ 281.5	$ 229.3
Weighted-average remaining lease term and weighted-average discount rates
Weighted average remaining lease term, Operating leases	6 years 8 months 12 days	6 years 8 months 12 days
Weighted average remaining lease term, Finance leases	3 years	2 years 7 months 6 days
Weighted-average discount rate, Operating leases	3.20%	3.90%
Weighted-average discount rate, Finance leases	1.80%	2.70%

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Dividends and Reconciliation of Outstanding Common Shares (Details) - Common stock - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended					12 Months Ended
	Feb. 29, 2020	Nov. 30, 2018	May 31, 2018	May 31, 2017	Feb. 29, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock Dividends
Dividends declared per common share (in dollars per share)						$ 2.24	$ 2.18	$ 2.10
Reconciliation of Outstanding Common Shares
Outstanding shares at beginning of period						276.6	279.5	289
Shares issued						2.6	2.6	2.6
Treasury stock acquired						(5.9)	(5.5)	(12.1)
Outstanding shares at end of period						273.3	276.6	279.5
Common stock share repurchase disclosures
Share repurchase program, maximum authorized amount (in dollars)	$ 900	$ 500	$ 300	$ 250	$ 400

Stockholders' Equity - Other Co

Stockholders' Equity - Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Comprehensive Income (Loss)
Other comprehensive income (loss), pre-tax	$ 1,683.6	$ 3,326.3	$ (2,258.6)
Other comprehensive income (loss), tax	(336.6)	(719.6)	422.9
Other comprehensive income (loss)	1,347	2,606.7	(1,835.7)
Net unrealized gains (losses) on available-for-sale securities including NCI
Other Comprehensive Income (Loss)
Other comprehensive income (loss) before reclassifications, pre-tax	3,441.4	4,414.1	(2,517.5)
Adjustments for assumed changes in amortization patterns, pre-tax	(179)	(293)	185.9
Adjustments for assumed changes in policyholder liabilities, pre-tax	(1,478.2)	(847.7)	346.9
Other comprehensive income (loss), pre-tax	1,731.3	3,320.8	(1,928.3)
Other comprehensive income (loss) before reclassifications, tax	(728.7)	(947)	515.4
Reclassification from accumulated other comprehensive income, tax	12.6	(9.7)	(5.3)
Adjustments for assumed changes in amortization patterns, tax	37.6	61.5	(39.1)
Adjustments for assumed changes in policyholder liabilities, tax	323.7	190.5	(72.3)
Other comprehensive income (loss), tax	(354.8)	(704.7)	398.7
Other comprehensive income (loss) before reclassifications, after-tax	2,712.7	3,467.1	(2,002.1)
Reclassification from accumulated other comprehensive income, after-tax	(40.3)	37.7	51.1
Adjustments for assumed changes in amortization patterns, after-tax	(141.4)	(231.5)	146.8
Adjustments for assumed changes in policyholder liabilities, after-tax	(1,154.5)	(657.2)	274.6
Other comprehensive income (loss)	1,376.5	2,616.1	(1,529.6)
Net unrealized gains (losses) on available-for-sale securities including NCI | Net realized capital gains (losses)
Other Comprehensive Income (Loss)
Reclassification from accumulated other comprehensive income, pre-tax	(52.9)	47.4	56.4
Noncredit component of impairment losses on fixed maturities available-for-sale including NCI
Other Comprehensive Income (Loss)
Other comprehensive income (loss) before reclassifications, pre-tax		5.2	39.7
Adjustments for assumed changes in amortization patterns, pre-tax		(1.4)	(5.3)
Adjustments for assumed changes in policyholder liabilities, pre-tax			(0.8)
Other comprehensive income (loss), pre-tax		3.8	33.6
Other comprehensive income (loss) before reclassifications, tax		(1.1)	(8.4)
Adjustments for assumed changes in amortization patterns, tax		0.3	1.1
Adjustments for assumed changes in policyholder liabilities, tax			0.1
Other comprehensive income (loss), tax		(0.8)	(7.2)
Other comprehensive income (loss) before reclassifications, after-tax		4.1	31.3
Adjustments for assumed changes in amortization patterns, after-tax		(1.1)	(4.2)
Adjustments for assumed changes in policyholder liabilities, after-tax			(0.7)
Other comprehensive income (loss)		3	26.4
Net unrealized gains (losses) on derivative instruments including NCI
Other Comprehensive Income (Loss)
Other comprehensive income (loss) before reclassifications, pre-tax	(28.1)	(0.5)	50.4
Reclassification from accumulated other comprehensive income, pre-tax	(27.1)	(23.9)	(40.1)
Adjustments for assumed changes in amortization patterns, pre-tax	2.7	3.1	0.3
Adjustments for assumed changes in policyholder liabilities, pre-tax	7.8	7.9	5.7
Other comprehensive income (loss), pre-tax	(44.7)	(13.4)	16.3
Other comprehensive income (loss) before reclassifications, tax	6.5		(3.4)
Reclassification from accumulated other comprehensive income, tax	5.1	4.9	4.2
Adjustments for assumed changes in amortization patterns, tax	(0.5)	(0.6)	(0.1)
Adjustments for assumed changes in policyholder liabilities, tax	(1.6)	(1.9)	(1)
Other comprehensive income (loss), tax	9.5	2.4	(0.3)
Other comprehensive income (loss) before reclassifications, after-tax	(21.6)	(0.5)	47
Reclassification from accumulated other comprehensive income, after-tax	(22)	(19)	(35.9)
Adjustments for assumed changes in amortization patterns, after-tax	2.2	2.5	0.2
Adjustments for assumed changes in policyholder liabilities, after-tax	6.2	6	4.7
Other comprehensive income (loss)	(35.2)	(11)	16
Foreign currency translation adjustment including NCI
Other Comprehensive Income (Loss)
Other comprehensive income (loss) before reclassifications, pre-tax	(11.7)	(112.3)
Other comprehensive income (loss), pre-tax	31.3	(86.2)	(303.9)
Other comprehensive income (loss) before reclassifications, tax	(2.6)	7.5
Reclassification from accumulated other comprehensive income, tax	1.9
Other comprehensive income (loss), tax	(0.7)	7.5	16.3
Other comprehensive income (loss) before reclassifications, after-tax	(14.3)	(104.8)
Reclassification from accumulated other comprehensive income, after-tax	44.9	26.1
Other comprehensive income (loss)	30.6	(78.7)	(287.6)
Foreign currency translation adjustment including NCI | Net realized capital gains (losses)
Other Comprehensive Income (Loss)
Reclassification from accumulated other comprehensive income, pre-tax	43	26.1
Foreign currency translation adjustment relating to noncontrolling interest | Net income attributable to noncontrolling interest
Other Comprehensive Income (Loss)
Reclassification from accumulated other comprehensive income, pre-tax	8.7	5.7
Unrecognized postretirement benefit obligation including NCI
Other Comprehensive Income (Loss)
Other comprehensive income (loss) before reclassifications, pre-tax	(91.9)	43.6	(125.3)
Other comprehensive income (loss), pre-tax	(34.3)	101.3	(76.3)
Other comprehensive income (loss) before reclassifications, tax	24.9	(8.6)	29.4
Reclassification from accumulated other comprehensive income, tax	(15.5)	(15.4)	(14)
Other comprehensive income (loss), tax	9.4	(24)	15.4
Other comprehensive income (loss) before reclassifications, after-tax	(67)	35	(95.9)
Reclassification from accumulated other comprehensive income, after-tax	42.1	42.3	35
Other comprehensive income (loss)	(24.9)	77.3	(60.9)
Unrecognized postretirement benefit obligation including NCI | Operating expense
Other Comprehensive Income (Loss)
Reclassification from accumulated other comprehensive income, pre-tax	$ 57.6	$ 57.7	$ 49

Stockholders' Equity - AOCI and

Stockholders' Equity - AOCI and Noncontrolling Interest (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in accumulated other comprehensive income (loss) rollforward
Balances		$ 14,618
Purchase of subsidiary shares from noncontrolling interest	[1]	(1.4)	$ (0.6)	$ (24)
Balances		16,558.9	14,618
Change in redeemable noncontrolling interest rollforward
Redeemable noncontrolling interest, balance at beginning of period		264.9	391.2	101.3
Net income (loss) attributable to redeemable noncontrolling interest		7.5	33.6	(2.1)
Redeemable noncontrolling interest of deconsolidated entities		(91.9)	(505.4)	(10.6)
Contributions from redeemable noncontrolling interest		136.2	402.1	355
Distributions to redeemable noncontrolling interest		(62)	(66.3)	(36.8)
Purchase of subsidiary shares from redeemable noncontrolling interest			(1.1)	(7.1)
Change in redemption value of redeemable noncontrolling interest		0.2	5.4	(7)
Stock-based compensation attributable to redeemable noncontrolling interest		0.1	0.1	0.1
Other comprehensive income (loss) attributable to redeemable noncontrolling interest		0.6	5.3	(1.6)
Redeemable noncontrolling interest, balance at end of period		255.6	264.9	391.2
Accumulated other comprehensive income (loss)
Change in accumulated other comprehensive income (loss) rollforward
Balances		1,037.9	(1,565.1)	165.5
Other comprehensive income (loss) during the period, net of adjustments		1,329.2	2,518.6	(1,907.8)
Amounts reclassified from accumulated other comprehensive income (loss)		16	84.4	76.6
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.		1,345.2	2,603	(1,831.2)
Purchase of subsidiary shares from noncontrolling interest	[1]			(1.6)
Balances		2,383.1	1,037.9	(1,565.1)
Accumulated other comprehensive income (loss) | ASU 2016-01 - Equity investments | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				(1)
Accumulated other comprehensive income (loss) | ASU 2014-09 - Revenue recognition | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				25.6
Accumulated other comprehensive income (loss) | ASU 2018-02 - Reclassification of certain tax effects | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				77.6
Net unrealized gains (losses) on available-for-sale securities
Change in accumulated other comprehensive income (loss) rollforward
Balances		2,806	190	1,470.7
Other comprehensive income (loss) during the period, net of adjustments		1,416.7	2,578.3	(1,580.6)
Amounts reclassified from accumulated other comprehensive income (loss)		(40.3)	37.7	51.1
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.		1,376.4	2,616	(1,529.5)
Balances		4,138.3	2,806	190
Available-for-sale debt securities, allowance for credit losses		2.9
Net unrealized gains (losses) on available-for-sale securities | ASU 2016-01 - Equity investments | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				(1)
Net unrealized gains (losses) on available-for-sale securities | ASU 2018-02 - Reclassification of certain tax effects | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				249.8
Net unrealized gains (losses) on available-for-sale securities | ASU 2016-13 - CECL | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances		(44.1)
Balances			(44.1)
Noncredit component of impairment losses on fixed maturities available-for-sale
Change in accumulated other comprehensive income (loss) rollforward
Balances		(44.1)	(47.1)	(58.3)
Amounts reclassified from accumulated other comprehensive income (loss)			3	26.4
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.			3	26.4
Balances			(44.1)	(47.1)
Noncredit component of impairment losses on fixed maturities available-for-sale | ASU 2018-02 - Reclassification of certain tax effects | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				(15.2)
Noncredit component of impairment losses on fixed maturities available-for-sale | ASU 2016-13 - CECL | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances		44.1
Balances			44.1
Net unrealized gains (losses) on derivative instruments
Change in accumulated other comprehensive income (loss) rollforward
Balances		53.4	64.4	42.7
Other comprehensive income (loss) during the period, net of adjustments		(13.2)	8	51.9
Amounts reclassified from accumulated other comprehensive income (loss)		(22)	(19)	(35.9)
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.		(35.2)	(11)	16
Balances		18.2	53.4	64.4
Net unrealized gains (losses) on derivative instruments | ASU 2018-02 - Reclassification of certain tax effects | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				5.7
Foreign currency translation adjustment
Change in accumulated other comprehensive income (loss) rollforward
Balances		(1,341.8)	(1,259.5)	(918.5)
Other comprehensive income (loss) during the period, net of adjustments		(7.3)	(102.7)	(283.2)
Amounts reclassified from accumulated other comprehensive income (loss)		36.2	20.4
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.		28.9	(82.3)	(283.2)
Purchase of subsidiary shares from noncontrolling interest				(1.6)
Balances		(1,312.9)	(1,341.8)	(1,259.5)
Foreign currency translation adjustment | ASU 2014-09 - Revenue recognition | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				25.6
Foreign currency translation adjustment | ASU 2018-02 - Reclassification of certain tax effects | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				(81.8)
Unrecognized postretirement benefit obligation
Change in accumulated other comprehensive income (loss) rollforward
Balances		(435.6)	(512.9)	(371.1)
Other comprehensive income (loss) during the period, net of adjustments		(67)	35	(95.9)
Amounts reclassified from accumulated other comprehensive income (loss)		42.1	42.3	35
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.		(24.9)	77.3	(60.9)
Balances		$ (460.5)	$ (435.6)	(512.9)
Unrecognized postretirement benefit obligation | ASU 2018-02 - Reclassification of certain tax effects | Effects of implementation of accounting change
Change in accumulated other comprehensive income (loss) rollforward
Balances				$ (80.9)
[1]	Excludes amounts attributable to redeemable noncontrolling interest. See Note 13, Stockholders’ Equity, for further details.

Stockholders' Equity - Dividend

Stockholders' Equity - Dividend Limitations (Details) - Principal Life Insurance Company only $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Dividend Limitations
Dividend limitation as percentage of statutory policyholder surplus (as a percent)	10.00%
Dividends that can be paid in upcoming calendar year without exceeding statutory limitation	$ 932.5

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	$ 78,710.3	$ 70,106.2
Fixed maturities, trading	532.1	675.9
Equity securities	2,013.4	1,879.4
Derivative instruments, assets	463.5	294.7
Separate account assets	175,951.4	165,468
Investment and universal life contracts	$ (467.8)	(214.2)
Fixed maturities valued using internal pricing models
Fixed maturities classified as Level 3 assets, percent valued using internal pricing models (as a percent)	1.00%
Amount measured at net asset value
Assets (liabilities) measured at fair value on a recurring basis
Unfunded commitments of investments measured using NAV	$ 15.1	19.9
U.S. government and agencies
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	2,111.5	1,724.2
Non-U.S. governments
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	1,073.7	996.2
States and political subdivisions
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	9,167.8	7,490
Corporate debt securities
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	47,354.8	40,647.4
Residential mortgage-backed pass-through securities
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	2,986.8	2,982.4
Commercial mortgage-backed securities
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	4,942.3	4,850.2
Collateralized debt obligations
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	4,027.5	3,215.3
Other debt obligations
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	7,045.9	8,200.5
Recurring Fair Value Measurements
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	78,710.3	70,106.2
Fixed maturities, trading	532.1	675.9
Equity securities	2,013.4	1,879.4
Derivative instruments, assets	463.5	294.7
Other investments	746.3	796
Cash equivalents	1,466.4	1,299
Sub-total excluding separate account assets	83,932	75,051.2
Separate account assets	175,951.4	165,468
Total assets	259,883.4	240,519.2
Investment and universal life contracts	(467.8)	(214.2)
Derivative liabilities	(186.1)	(217.7)
Other liabilities	(0.4)	(98.9)
Total liabilities	(654.3)	(530.8)
Net assets (liabilities)	259,229.1	239,988.4
Recurring Fair Value Measurements | Amount measured at net asset value
Assets (liabilities) measured at fair value on a recurring basis
Other investments	75.7	78.3
Sub-total excluding separate account assets	75.7	78.3
Separate account assets	155.8	129
Total assets	231.5	207.3
Net assets (liabilities)	231.5	207.3
Recurring Fair Value Measurements | Fair value hierarchy Level 1
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	1,769.4	1,339.9
Fixed maturities, trading	0.5	0.5
Equity securities	659.7	645.8
Other investments	252.8	335.2
Cash equivalents	38.3	40.9
Sub-total excluding separate account assets	2,720.7	2,362.3
Separate account assets	102,550.5	95,652.5
Total assets	105,271.2	98,014.8
Net assets (liabilities)	105,271.2	98,014.8
Recurring Fair Value Measurements | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	76,580.5	68,381.4
Fixed maturities, trading	531.6	675.1
Equity securities	1,353.7	1,233.6
Derivative instruments, assets	462.9	265.4
Other investments	385.9	343.5
Cash equivalents	1,428.1	1,258.1
Sub-total excluding separate account assets	80,742.7	72,157.1
Separate account assets	64,351.9	60,718.5
Total assets	145,094.6	132,875.6
Derivative liabilities	(180.4)	(201.4)
Other liabilities	(0.4)	(98.9)
Total liabilities	(180.8)	(300.3)
Net assets (liabilities)	144,913.8	132,575.3
Recurring Fair Value Measurements | Fair value hierarchy Level 3
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	360.4	384.9
Fixed maturities, trading		0.3
Derivative instruments, assets	0.6	29.3
Other investments	31.9	39
Sub-total excluding separate account assets	392.9	453.5
Separate account assets	8,893.2	8,968
Total assets	9,286.1	9,421.5
Investment and universal life contracts	(467.8)	(214.2)
Derivative liabilities	(5.7)	(16.3)
Total liabilities	(473.5)	(230.5)
Net assets (liabilities)	8,812.6	9,191
Recurring Fair Value Measurements | U.S. government and agencies
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	2,111.5	1,724.2
Recurring Fair Value Measurements | U.S. government and agencies | Fair value hierarchy Level 1
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	1,768.3	1,320
Recurring Fair Value Measurements | U.S. government and agencies | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	343.2	404.2
Recurring Fair Value Measurements | Non-U.S. governments
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	1,073.7	996.2
Recurring Fair Value Measurements | Non-U.S. governments | Fair value hierarchy Level 1
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	1.1	1.4
Recurring Fair Value Measurements | Non-U.S. governments | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	1,072.6	994.8
Recurring Fair Value Measurements | States and political subdivisions
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	9,167.8	7,490
Recurring Fair Value Measurements | States and political subdivisions | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	9,167.8	7,490
Recurring Fair Value Measurements | Corporate debt securities
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	47,354.8	40,647.4
Recurring Fair Value Measurements | Corporate debt securities | Fair value hierarchy Level 1
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale		18.5
Recurring Fair Value Measurements | Corporate debt securities | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	47,064	40,547.2
Recurring Fair Value Measurements | Corporate debt securities | Fair value hierarchy Level 3
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	290.8	81.7
Recurring Fair Value Measurements | Residential mortgage-backed pass-through securities
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	2,986.8	2,982.4
Recurring Fair Value Measurements | Residential mortgage-backed pass-through securities | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	2,986.8	2,982.4
Recurring Fair Value Measurements | Commercial mortgage-backed securities
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	4,942.3	4,850.2
Recurring Fair Value Measurements | Commercial mortgage-backed securities | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	4,929.1	4,837.3
Recurring Fair Value Measurements | Commercial mortgage-backed securities | Fair value hierarchy Level 3
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	13.2	12.9
Recurring Fair Value Measurements | Collateralized debt obligations
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	4,027.5	3,215.3
Recurring Fair Value Measurements | Collateralized debt obligations | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	4,000.3	3,016.3
Recurring Fair Value Measurements | Collateralized debt obligations | Fair value hierarchy Level 3
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	27.2	199
Recurring Fair Value Measurements | Other debt obligations
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	7,045.9	8,200.5
Recurring Fair Value Measurements | Other debt obligations | Fair value hierarchy Level 2
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	7,016.7	8,109.2
Recurring Fair Value Measurements | Other debt obligations | Fair value hierarchy Level 3
Assets (liabilities) measured at fair value on a recurring basis
Fixed maturities, available-for-sale	$ 29.2	$ 91.3

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Fair Value Measurements (Details) - Recurring Fair Value Measurements - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, net derivative assets	$ 13	$ 3.1	$ 18.1
Total realized/unrealized gains (losses) included in net income, net derivative assets	11.8	(0.8)	(20.2)
Net purchases, sales, issuances and settlements, net derivative assets	(3.4)	10.7	5.2
Transfers out of Level 3, net derivative assets	(26.5)
Ending balance, net derivative assets	(5.1)	13	3.1
Changes in unrealized gains (losses) included in net income relating to positions still held, net derivative assets (liabilities)	9.9	5.3	(18.4)
Gross purchases, sales, issuances and settlements
Purchases, net derivative assets (liabilities)		1.9	1.8
Sales, net derivative assets (liabilities)	(3.4)	8.8	3.4
Net purchases, sales, issuances and settlements, net derivative assets (liabilities)	(3.4)	10.7	5.2
Investment and universal life contracts
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, liabilities	(214.2)	(45.2)	(160.3)
Total realized/unrealized gains (losses) included in net income, liabilities	(254.9)	(145.5)	107.5
Total realized/unrealized gains (losses) included in other comprehensive income, liabilities	(0.3)	(0.2)	0.1
Net purchases, sales, issuances and settlements, liabilities	1.6	(23.3)	7.5
Ending balance, liabilities	(467.8)	(214.2)	(45.2)
Changes in unrealized gains (losses) included in net income relating to positions still held, liabilities	(262.1)	(146)	109.9
Changes in unrealized gains (losses) included in OCI relating to positions still held, liabilities	(0.3)
Gross purchases, sales, issuances and settlements
Issuances, liabilities	(23)	(33.4)	2.8
Settlements, liabilities	24.6	10.1	4.7
Net purchases, sales, issuances and settlements, liabilities	1.6	(23.3)	7.5
Fixed maturities | Available-for-sale
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	384.9	138.8	273.3
Total realized/unrealized gains (losses) included in net income, assets	(4.5)	(6.4)	(5.4)
Total realized/unrealized gains (losses) included in other comprehensive income, assets	(16.7)	7.6
Net purchases, sales, issuances and settlements, assets	263	237.5	197.2
Transfers into Level 3, assets	388.4	86	59.3
Transfers out of Level 3, assets	(654.7)	(78.6)	(385.6)
Ending balance, assets	360.4	384.9	138.8
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	(3.4)	(5.5)	(2.8)
Changes in unrealized gains (losses) included in OCI relating to positions still held, assets	13.1
Gross purchases, sales, issuances and settlements
Purchases, assets	366	276.7	258.5
Sales, assets	(5.5)	(1.4)	(10.1)
Settlements, assets	(97.5)	(37.8)	(51.2)
Net purchases, sales, issuances and settlements, assets	263	237.5	197.2
Fixed maturities | Trading
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	0.3
Net purchases, sales, issuances and settlements, assets		0.3	3.7
Transfers out of Level 3, assets	(0.3)		(3.7)
Ending balance, assets		0.3
Gross purchases, sales, issuances and settlements
Purchases, assets		0.5	3.7
Settlements, assets		(0.2)
Net purchases, sales, issuances and settlements, assets		0.3	3.7
Non-U.S. governments | Available-for-sale
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets		4.6	7.4
Total realized/unrealized gains (losses) included in other comprehensive income, assets			(0.1)
Net purchases, sales, issuances and settlements, assets		(4.6)	(1.4)
Transfers out of Level 3, assets			(1.3)
Ending balance, assets			4.6
Gross purchases, sales, issuances and settlements
Settlements, assets		(4.6)	(1.4)
Net purchases, sales, issuances and settlements, assets		(4.6)	(1.4)
Corporate debt securities | Available-for-sale
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	81.7	57.9	128
Total realized/unrealized gains (losses) included in net income, assets	(0.9)		(1)
Total realized/unrealized gains (losses) included in other comprehensive income, assets	5.2	2.5	(0.1)
Net purchases, sales, issuances and settlements, assets	118	17.2	(15.2)
Transfers into Level 3, assets	342	4.1	1
Transfers out of Level 3, assets	(255.2)		(54.8)
Ending balance, assets	290.8	81.7	57.9
Changes in unrealized gains (losses) included in OCI relating to positions still held, assets	11.9
Gross purchases, sales, issuances and settlements
Purchases, assets	169.2	41.9	12.9
Sales, assets	(5.5)	(1.4)	(10.1)
Settlements, assets	(45.7)	(23.3)	(18)
Net purchases, sales, issuances and settlements, assets	118	17.2	(15.2)
Commercial mortgage-backed securities | Available-for-sale
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	12.9	9.5	10.6
Total realized/unrealized gains (losses) included in net income, assets	(1.3)	(3.8)	(3.5)
Total realized/unrealized gains (losses) included in other comprehensive income, assets	1.4	3.4	0.2
Net purchases, sales, issuances and settlements, assets	(0.1)	2.4	0.1
Transfers into Level 3, assets	0.3	3.7	3.6
Transfers out of Level 3, assets		(2.3)	(1.5)
Ending balance, assets	13.2	12.9	9.5
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	(1.2)	(2.9)	(1.9)
Changes in unrealized gains (losses) included in OCI relating to positions still held, assets	1.5
Gross purchases, sales, issuances and settlements
Purchases, assets		2.4
Settlements, assets	(0.1)		0.1
Net purchases, sales, issuances and settlements, assets	(0.1)	2.4	0.1
Collateralized debt obligations | Available-for-sale
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	199	8.3	125
Total realized/unrealized gains (losses) included in net income, assets	(2.3)	(2.6)	(0.9)
Total realized/unrealized gains (losses) included in other comprehensive income, assets	(21.9)	0.9	0.2
Net purchases, sales, issuances and settlements, assets	183	122.5	66.3
Transfers into Level 3, assets		69.9	54.7
Transfers out of Level 3, assets	(330.6)		(237)
Ending balance, assets	27.2	199	8.3
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	(2.2)	(2.6)	(0.9)
Changes in unrealized gains (losses) included in OCI relating to positions still held, assets	(0.3)
Gross purchases, sales, issuances and settlements
Purchases, assets	182.5	124.7	93.6
Settlements, assets	0.5	(2.2)	(27.3)
Net purchases, sales, issuances and settlements, assets	183	122.5	66.3
Other debt obligations | Available-for-sale
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	91.3	58.5	2.3
Total realized/unrealized gains (losses) included in other comprehensive income, assets	(1.4)	0.8	(0.2)
Net purchases, sales, issuances and settlements, assets	(37.9)	100	147.4
Transfers into Level 3, assets	46.1	8.3
Transfers out of Level 3, assets	(68.9)	(76.3)	(91)
Ending balance, assets	29.2	91.3	58.5
Gross purchases, sales, issuances and settlements
Purchases, assets	14.3	107.7	152
Settlements, assets	(52.2)	(7.7)	(4.6)
Net purchases, sales, issuances and settlements, assets	(37.9)	100	147.4
Equity securities
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets			2.7
Total realized/unrealized gains (losses) included in net income, assets			12.9
Net purchases, sales, issuances and settlements, assets			(15.6)
Gross purchases, sales, issuances and settlements
Sales, assets			(15.6)
Net purchases, sales, issuances and settlements, assets			(15.6)
Other investments
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	39	17.2	6.5
Total realized/unrealized gains (losses) included in net income, assets	6.3	6	1.7
Total realized/unrealized gains (losses) included in other comprehensive income, assets	(2.9)
Net purchases, sales, issuances and settlements, assets	(10.5)	5.8	9
Transfers into Level 3, assets		10
Ending balance, assets	31.9	39	17.2
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	5.3	6	1.7
Changes in unrealized gains (losses) included in OCI relating to positions still held, assets	(2.9)
Gross purchases, sales, issuances and settlements
Purchases, assets	0.5	10.7	9
Sales, assets	(11)	(4.9)
Net purchases, sales, issuances and settlements, assets	(10.5)	5.8	9
Separate account assets
Changes in Level 3 fair value measurements rollforward, assets and liabilities
Beginning balance, assets	8,968	8,615.5	7,651.4
Total realized/unrealized gains (losses) included in net income, assets	463.7	739.9	869.5
Total realized/unrealized gains (losses) included in other comprehensive income, assets			(0.3)
Net purchases, sales, issuances and settlements, assets	(538.5)	(214.2)	133.7
Transfers into Level 3, assets			2.3
Transfers out of Level 3, assets		(173.2)	(41.1)
Ending balance, assets	8,893.2	8,968	8,615.5
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	385.5	697.1	829.8
Gross purchases, sales, issuances and settlements
Purchases, assets	309.2	279.1	743
Sales, assets	(658.2)	(526.4)	(608.4)
Issuances, assets	(396.1)	(280.4)	(206.5)
Settlements, assets	206.6	313.5	205.6
Net purchases, sales, issuances and settlements, assets	$ (538.5)	$ (214.2)	$ 133.7

Fair Value Measurements - Trans

Fair Value Measurements - Transfers (Details) - Recurring Fair Value Measurements - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Hierarchy Levels Transfers
Transfers out of Level 3 into Level 2, net derivative assets (liabilities)	$ 26.5
Other investments
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3		$ 10
Separate account assets
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3			$ 2.3
Transfers out of Level 3 into Level 1			0.2
Transfers out of Level 3 into Level 2		173.2	40.9
Available-for-sale | Fixed maturities
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3	388.4	86	59.3
Transfers out of Level 3 into Level 2	654.7	78.6	385.6
Available-for-sale | Non-U.S. governments
Fair Value Hierarchy Levels Transfers
Transfers out of Level 3 into Level 2			1.3
Available-for-sale | Corporate debt securities
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3	342	4.1	1
Transfers out of Level 3 into Level 2	255.2		54.8
Available-for-sale | Commercial mortgage-backed securities
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3	0.3	3.7	3.6
Transfers out of Level 3 into Level 2		2.3	1.5
Available-for-sale | Collateralized debt obligations
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3		69.9	54.7
Transfers out of Level 3 into Level 2	330.6		237
Available-for-sale | Other debt obligations
Fair Value Hierarchy Levels Transfers
Transfers out of Level 2 into Level 3	46.1	8.3
Transfers out of Level 3 into Level 2	68.9	$ 76.3	91
Trading | Fixed maturities
Fair Value Hierarchy Levels Transfers
Transfers out of Level 3 into Level 2	$ 0.3		$ 3.7

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information for Level 3 Measurements (Details) - Recurring Fair Value Measurements $ in Millions	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)item
Unobservable inputs
Assets measured at fair value | $	$ 259,883.4	$ 240,519.2
Liabilities measured at fair value | $	(654.3)	(530.8)
Fair value hierarchy Level 3
Unobservable inputs
Assets measured at fair value | $	9,286.1	9,421.5
Liabilities measured at fair value | $	(473.5)	(230.5)
Fair value hierarchy Level 3 | Investment and universal life contracts
Unobservable inputs
Liabilities measured at fair value | $	$ (467.8)	$ (214.2)
Embedded derivative, Valuation technique	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long duration interest rate | Minimum
Unobservable inputs
Embedded derivative, Input	0.012	0.020
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long duration interest rate | Maximum
Unobservable inputs
Embedded derivative, Input	0.014	0.021
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long duration interest rate | Weighted average input
Unobservable inputs
Embedded derivative, Input	0.013
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long-term equity market volatility | Minimum
Unobservable inputs
Embedded derivative, Input	0.176	0.150
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long-term equity market volatility | Maximum
Unobservable inputs
Embedded derivative, Input	0.269	0.269
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long-term equity market volatility | Weighted average input
Unobservable inputs
Embedded derivative, Input	0.196
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Non-performance risk | Minimum
Unobservable inputs
Embedded derivative, Input	0.001	0.002
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Non-performance risk | Maximum
Unobservable inputs
Embedded derivative, Input	0.014	0.013
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Non-performance risk | Weighted average input
Unobservable inputs
Embedded derivative, Input	0.009
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Lapse rate | Minimum
Unobservable inputs
Embedded derivative, Input	0	0
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Lapse rate | Maximum
Unobservable inputs
Embedded derivative, Input	0.160	0.180
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Lapse rate | Weighted average input
Unobservable inputs
Embedded derivative, Input	0.058
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale
Unobservable inputs
Assets measured at fair value | $	$ 286.1	$ 72.5
Fixed maturities, available-for-sale, Valuation technique	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Discount rate | Minimum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.009	0.019
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Discount rate | Maximum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.117	0.051
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Discount rate | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.073	0.038
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Illiquidity premium | Minimum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0	0
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Illiquidity premium | Maximum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.0060	0.0410
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Illiquidity premium | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.0019	0.0152
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Comparability adjustment | Minimum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Comparability adjustment | Maximum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.0769
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Comparability adjustment | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.0359
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Probability of default | Minimum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Probability of default | Maximum
Unobservable inputs
Fixed maturities, available-for-sale, Input	1
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Probability of default | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.003
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Potential loss severity | Minimum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Potential loss severity | Maximum
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.546
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Potential loss severity | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.002
Fair value hierarchy Level 3 | Commercial mortgage-backed securities | Available-for-sale
Unobservable inputs
Assets measured at fair value | $	$ 1.1	$ 2.4
Fixed maturities, available-for-sale, Valuation technique	gaap:ValuationTechniqueDiscountedCashFlowMember	gaap:ValuationTechniqueDiscountedCashFlowMember
Fair value hierarchy Level 3 | Commercial mortgage-backed securities | Available-for-sale | Discounted cash flow | Probability of default
Unobservable inputs
Fixed maturities, available-for-sale, Input	1	1
Fair value hierarchy Level 3 | Commercial mortgage-backed securities | Available-for-sale | Discounted cash flow | Probability of default | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	1	1
Fair value hierarchy Level 3 | Commercial mortgage-backed securities | Available-for-sale | Discounted cash flow | Potential loss severity
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.784	0.531
Fair value hierarchy Level 3 | Commercial mortgage-backed securities | Available-for-sale | Discounted cash flow | Potential loss severity | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.784	0.531
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale
Unobservable inputs
Assets measured at fair value | $	$ 0.7	$ 108.7
Fixed maturities, available-for-sale, Valuation technique	gaap:ValuationTechniqueDiscountedCashFlowMember	gaap:ValuationTechniqueDiscountedCashFlowMember
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Minimum
Unobservable inputs
Fixed maturities, available-for-sale, Input		0.029
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Maximum
Unobservable inputs
Fixed maturities, available-for-sale, Input		0.100
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input		0.034
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Probability of default
Unobservable inputs
Fixed maturities, available-for-sale, Input	1	1
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Probability of default | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	1	1
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Potential loss severity
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.405	0.230
Fair value hierarchy Level 3 | Collateralized debt obligations | Available-for-sale | Discounted cash flow | Potential loss severity | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.405	0.230
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale
Unobservable inputs
Assets measured at fair value | $	$ 0.8	$ 1.2
Fixed maturities, available-for-sale, Valuation technique	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Discount rate
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.100	0.050
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.100	0.050
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Illiquidity premium
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.0500	0.0500
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Illiquidity premium | Weighted average input
Unobservable inputs
Fixed maturities, available-for-sale, Input	0.0500	0.0500
Fair value hierarchy Level 3 | Other investments
Unobservable inputs
Assets measured at fair value | $	$ 30.4	$ 14.8
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, other investments | Discount rate | Minimum
Unobservable inputs
Other investments, Input	0.250	0.250
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, other investments | Discount rate | Maximum
Unobservable inputs
Other investments, Input	0.300	0.300
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, other investments | Discount rate | Weighted average input
Unobservable inputs
Other investments, Input	0.275	0.275
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, other investments | Terminal earnings before interest, taxes, depreciation and amortization multiple | Minimum
Unobservable inputs
Other investments, Input	3.8	3.5
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, other investments | Terminal earnings before interest, taxes, depreciation and amortization multiple | Maximum
Unobservable inputs
Other investments, Input	4.7	4.5
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, other investments | Terminal earnings before interest, taxes, depreciation and amortization multiple | Weighted average input
Unobservable inputs
Other investments, Input	4.2	4
Fair value hierarchy Level 3 | Other investments | Market comparables | Revenue multiples | Minimum
Unobservable inputs
Other investments, Input	6	0.8
Fair value hierarchy Level 3 | Other investments | Market comparables | Revenue multiples | Maximum
Unobservable inputs
Other investments, Input	8	7
Fair value hierarchy Level 3 | Other investments | Market comparables | Revenue multiples | Weighted average input
Unobservable inputs
Other investments, Input	7	4.1
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate | Discount rate
Unobservable inputs
Other investments, Input	0.065
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate | Discount rate | Weighted average input
Unobservable inputs
Other investments, Input	0.065
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate | Terminal capitalization rate
Unobservable inputs
Other investments, Input	0.053
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate | Terminal capitalization rate | Weighted average input
Unobservable inputs
Other investments, Input	0.053
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate | Average market rent growth rate
Unobservable inputs
Other investments, Input	0.026
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate | Average market rent growth rate | Weighted average input
Unobservable inputs
Other investments, Input	0.026
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate debt | Credit spread rate
Unobservable inputs
Other investments, Input	0.033
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate debt | Credit spread rate | Weighted average input
Unobservable inputs
Other investments, Input	0.033
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate debt | Loan to value
Unobservable inputs
Other investments, Input	0.526
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, real estate debt | Loan to value | Weighted average input
Unobservable inputs
Other investments, Input	0.526
Fair value hierarchy Level 3 | Separate account assets
Unobservable inputs
Assets measured at fair value | $	$ 8,893.2	$ 8,966.2
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Discount rate
Unobservable inputs
Separate account assets, Input	0.012	0.028
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Discount rate | Weighted average input
Unobservable inputs
Separate account assets, Input	0.012	0.028
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Illiquidity premium
Unobservable inputs
Separate account assets, Input	0.0060	0.0060
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Illiquidity premium | Weighted average input
Unobservable inputs
Separate account assets, Input	0.0060	0.0060
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Credit spread rate
Unobservable inputs
Separate account assets, Input	0.0110	0.0120
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Credit spread rate | Weighted average input
Unobservable inputs
Separate account assets, Input	0.0110	0.0120
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Discount rate | Minimum
Unobservable inputs
Separate account assets, Input	0.056	0.055
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Discount rate | Maximum
Unobservable inputs
Separate account assets, Input	0.119	0.118
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Discount rate | Weighted average input
Unobservable inputs
Separate account assets, Input	0.069	0.067
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Terminal capitalization rate | Minimum
Unobservable inputs
Separate account assets, Input	0.045	0.045
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Terminal capitalization rate | Maximum
Unobservable inputs
Separate account assets, Input	0.093	0.093
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Terminal capitalization rate | Weighted average input
Unobservable inputs
Separate account assets, Input	0.057	0.057
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Average market rent growth rate | Minimum
Unobservable inputs
Separate account assets, Input	0.015	0.020
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Average market rent growth rate | Maximum
Unobservable inputs
Separate account assets, Input	0.048	0.047
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Average market rent growth rate | Weighted average input
Unobservable inputs
Separate account assets, Input	0.030	0.030
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Loan to value | Minimum
Unobservable inputs
Separate account assets, Input	0.063	0.080
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Loan to value | Maximum
Unobservable inputs
Separate account assets, Input	0.742	0.804
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Loan to value | Weighted average input
Unobservable inputs
Separate account assets, Input	0.475	0.459
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Market interest rate | Minimum
Unobservable inputs
Separate account assets, Input	0.020	0.032
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Market interest rate | Maximum
Unobservable inputs
Separate account assets, Input	0.050	0.058
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Market interest rate | Weighted average input
Unobservable inputs
Separate account assets, Input	0.034	0.036

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Option on Consolidated VIEs and Equity Method Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commercial Mortgage Loans of Consolidated VIEs
Fair Value Option, Quantitative Disclosures
Pre-tax gain (loss) due to change in fair value of assets and liabilities for which the fair value option was elected		$ 0.1	$ (0.2)
Interest income		0.3	0.7
Real Estate Ventures
Fair Value Option, Quantitative Disclosures
Fair value of assets for which fair value option was elected	$ 28.5	22.8
Pre-tax gain (loss) due to change in fair value of assets and liabilities for which the fair value option was elected	$ 5.3	$ 6	$ 1.7

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments Not Reported at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets (liabilities)
Mortgage loans	$ 17,343	$ 16,486.9
Policy loans	784	798
Short-term debt	(84.7)	(93.4)
Long-term debt	(4,279.2)	(3,734.1)
Carrying amount
Assets (liabilities)
Mortgage loans	17,343	16,486.9
Policy loans	784	798
Other investments	347.2	278.8
Cash and cash equivalents not required to be reported at fair value	1,383.4	1,216.9
Investment contracts	(35,449.9)	(33,922.2)
Short-term debt	(84.7)	(93.4)
Long-term debt	(4,279.2)	(3,734.1)
Separate account liabilities	(160,316.4)	(151,132.4)
Bank deposits	(423.5)	(469.6)
Cash collateral payable	(224.6)	(156.8)
Assets (liabilities) measured at fair value
Assets (liabilities)
Mortgage loans	18,762.6	17,214.7
Policy loans	1,037.7	1,030.8
Other investments	338.5	273.1
Cash and cash equivalents not required to be reported at fair value	1,383.4	1,216.9
Investment contracts	(36,738.7)	(34,001.3)
Short-term debt	(84.7)	(93.4)
Long-term debt	(4,949.9)	(4,122.9)
Separate account liabilities	(159,129.2)	(149,955.6)
Bank deposits	(429.7)	(468.3)
Cash collateral payable	(224.6)	(156.8)
Assets (liabilities) measured at fair value | Fair value hierarchy Level 1
Assets (liabilities)
Cash and cash equivalents not required to be reported at fair value	1,369.7	1,193.3
Cash collateral payable	(224.6)	(156.8)
Assets (liabilities) measured at fair value | Fair value hierarchy Level 2
Assets (liabilities)
Other investments	247.1	180.3
Cash and cash equivalents not required to be reported at fair value	13.7	23.6
Investment contracts	(5,276.9)	(4,304.5)
Short-term debt	(84.7)	(93.4)
Long-term debt	(4,908.7)	(4,015.3)
Bank deposits	(429.7)	(468.3)
Assets (liabilities) measured at fair value | Fair value hierarchy Level 3
Assets (liabilities)
Mortgage loans	18,762.6	17,214.7
Policy loans	1,037.7	1,030.8
Other investments	91.4	92.8
Investment contracts	(31,461.8)	(29,696.8)
Long-term debt	(41.2)	(107.6)
Separate account liabilities	$ (159,129.2)	$ (149,955.6)

Statutory Insurance Financial_3

Statutory Insurance Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statutory disclosures
Impact of prescribed practices on statutory surplus		$ 862.1
Impact of permitted practices on statutory surplus		(151.3)
Statutory reserves assumed by affiliated reinsurance subsidiaries	$ 8,978.2	7,902.3
Admitted assets under prescribed and permitted statutory accounting practices	3,731	3,358
Statutory net income	915.9	989.3	$ 1,017.6
Statutory capital and surplus	$ 5,682.4	$ 5,193.4	$ 5,319.6

Segment Information - Reconcili

Segment Information - Reconciliation of Segment Assets to Consolidated (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Information: Assets
Total assets	$ 296,627.7	$ 276,087.8
Retirement and Income Solutions
Segment Information: Assets
Total assets	207,288.4	192,698.1
Principal Global Investors
Segment Information: Assets
Total assets	2,294.3	2,363.3
Principal International
Segment Information: Assets
Total assets	51,707.6	48,857.6
U.S. Insurance Solutions
Segment Information: Assets
Total assets	31,438.9	28,669.6
Corporate
Segment Information: Assets
Total assets	$ 3,898.5	$ 3,499.2

Segment Information - Reconci_2

Segment Information - Reconciliation of Segment Operating Revenues and Earnings to Consolidated (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Revenue And Profit (Loss) From Segments To Consolidated
Net realized capital gains (losses), net of related revenue adjustments									$ 195.3	$ (98.5)	$ (132.3)
Total revenues	$ 3,765.1	$ 3,310.7	$ 3,114.6	$ 4,551.3	$ 4,047.2	$ 4,458.4	$ 3,972.6	$ 3,743.9	14,741.7	16,222.1	14,237.2
Pre-tax net realized capital gains (losses), as adjusted									63.6	(140.9)	(126.4)
Income (loss) before income taxes									1,693.5	1,693.3	1,784.4
Retirement and Income Solutions
Operating Revenue And Profit (Loss) From Segments To Consolidated
Inter-segment revenues									342.6	357.8	393.6
Principal Global Investors
Operating Revenue And Profit (Loss) From Segments To Consolidated
Inter-segment revenues									273.8	264.9	262.8
Operating Segments
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									14,579.9	16,393.1	14,424.8
Pre-tax operating earnings (losses)									1,636.9	1,889.3	1,954.5
Operating Segments | Retirement and Income Solutions
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									7,503.5	8,954.4	7,277
Pre-tax operating earnings (losses)									966.9	874	922.2
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Fee
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									2,149.8	2,003	1,783.7
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Spread
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									5,353.7	6,951.4	5,493.3
Operating Segments | Principal Global Investors
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									1,539.1	1,505.8	1,736.3
Pre-tax operating earnings (losses)									512.9	483.3	562.1
Operating Segments | Principal International
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									1,096.8	1,523.2	1,372.9
Pre-tax operating earnings (losses)									243.6	390.7	272.6
Operating Segments | U.S. Insurance Solutions
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									4,480.2	4,449	4,089.8
Pre-tax operating earnings (losses)									239.9	521.6	467
Operating Segments | U.S. Insurance Solutions | Specialty Benefits insurance
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									2,525.4	2,493.6	2,326.4
Operating Segments | U.S. Insurance Solutions | Individual Life insurance
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									1,955	1,955.6	1,763.6
Operating Segments | U.S. Insurance Solutions | Eliminations
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									(0.2)	(0.2)	(0.2)
Operating Segments | Corporate
Operating Revenue And Profit (Loss) From Segments To Consolidated
Operating revenues									(39.7)	(39.3)	(51.2)
Pre-tax operating earnings (losses)									(326.4)	(380.3)	(269.4)
Reconciling Items
Operating Revenue And Profit (Loss) From Segments To Consolidated
Net realized capital gains (losses), net of related revenue adjustments									195.3	(98.5)	(132.3)
Adjustments related to equity method investments									(33.5)	(72.5)	(55.3)
Pre-tax net realized capital gains (losses), as adjusted									63.6	(140.9)	(126.4)
Earnings adjustments related to equity method investments and noncontrolling interest									$ (7)	$ (55.1)	$ (43.7)

Segment Information - Net Reali

Segment Information - Net Realized Capital Gains (Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Information: Net realized capital gains (losses), as adjusted
Net realized capital gains (losses)	$ 302.6	$ (52.8)	$ (75.4)
Derivative and hedging-related revenue adjustments	(132.9)	(80.4)	(64.9)
Market value adjustments to fee revenues	(1.6)		0.1
Adjustments related to equity method investments	(1.5)	2.6	(5.4)
Adjustments related to sponsored investment funds	17.3	23.6	12.9
Recognition of front-end fee revenue	11.4	8.5	0.4
Net realized capital gains (losses), net of related revenue adjustments	195.3	(98.5)	(132.3)
Amortization of deferred acquisition costs and other actuarial balances	(26.8)	(40.8)	(27)
Capital (gains) losses distributed	(49.9)	(68.2)	14.4
Market value adjustments of embedded derivatives	(55)	66.6	18.5
Pre-tax net realized capital gains (losses), as adjusted	$ 63.6	$ (140.9)	$ (126.4)

Segment Information - Income Ta

Segment Information - Income Tax Expense by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Information: Income tax expense (benefit)
Income taxes (benefits)	$ 265	$ 249.2	$ 230.7
Operating Segments
Segment Information: Income tax expense (benefit)
Total segment income tax expense (benefit) from operating earnings (losses)	270.5	320.2	357
Reconciling Items
Segment Information: Income tax expense (benefit)
Tax expense (benefit) related to net realized capital gains (losses), as adjusted	28.2	1.3	(71.4)
Tax expense (benefit) associated with certain adjustments related to equity method investments and noncontrolling interest	(33.7)	(72.3)	(54.9)
Retirement and Income Solutions | Operating Segments
Segment Information: Income tax expense (benefit)
Total segment income tax expense (benefit) from operating earnings (losses)	106.6	71.8	85.6
Principal Global Investors | Operating Segments
Segment Information: Income tax expense (benefit)
Total segment income tax expense (benefit) from operating earnings (losses)	141.9	121.8	149.1
Principal International | Operating Segments
Segment Information: Income tax expense (benefit)
Total segment income tax expense (benefit) from operating earnings (losses)	62	106.8	73.3
U.S. Insurance Solutions | Operating Segments
Segment Information: Income tax expense (benefit)
Total segment income tax expense (benefit) from operating earnings (losses)	47.9	101.8	85.7
Corporate | Operating Segments
Segment Information: Income tax expense (benefit)
Total segment income tax expense (benefit) from operating earnings (losses)	$ (87.9)	$ (82)	$ (36.7)

Segment Information - Depreciat

Segment Information - Depreciation and Amortization Expense by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Information: Depreciation and amortization expense
Depreciation and amortization expense	$ 186.6	$ 166.8	$ 151
Retirement and Income Solutions
Segment Information: Depreciation and amortization expense
Depreciation and amortization expense	69.1	48.2	32.5
Principal Global Investors
Segment Information: Depreciation and amortization expense
Depreciation and amortization expense	21.6	18.9	21.9
Principal International
Segment Information: Depreciation and amortization expense
Depreciation and amortization expense	56	58.6	59.6
U.S. Insurance Solutions
Segment Information: Depreciation and amortization expense
Depreciation and amortization expense	25.1	25	26.2
Corporate
Segment Information: Depreciation and amortization expense
Depreciation and amortization expense	$ 14.8	$ 16.1	$ 10.8

Revenues from Contracts with _3

Revenues from Contracts with Customers - Disaggregation by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from Contracts with Customers - Disaggregation of Revenues
Total fees and other revenues per consolidated statements of operations	$ 4,511.1	$ 4,409.9	$ 4,273.8
Operating Segments
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	2,768.3	2,610	2,658.9
Operating Segments | Retirement and Income Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	599.8	464.8	262.9
Operating Segments | Principal Global Investors
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	1,511.2	1,456.7	1,700.5
Fees and other revenues not within the scope of revenue recognition guidance	22.3	38.5	30.4
Total fees and other revenues per consolidated statements of operations	1,533.5	1,495.2	1,730.9
Operating Segments | Principal International
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	439.2	462.2	477.1
Fees and other revenues not within the scope of revenue recognition guidance	5.6	6.3	7.3
Total fees and other revenues per consolidated statements of operations	444.8	468.5	484.4
Operating Segments | U.S. Insurance Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	63.2	65.9	57
Operating Segments | Corporate
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	154.9	160.4	161.4
Fees and other revenues not within the scope of revenue recognition guidance	(303.9)	(301.8)	(316.3)
Total fees and other revenues per consolidated statements of operations	(149)	(141.4)	(154.9)
Operating Segments | Retirement and Income Solutions - Fee | Retirement and Income Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	591.2	455.5	252.4
Fees and other revenues not within the scope of revenue recognition guidance	1,130.4	1,139	1,132.9
Total fees and other revenues per consolidated statements of operations	1,721.6	1,594.5	1,385.3
Operating Segments | Retirement and Income Solutions - Spread | Retirement and Income Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	8.6	9.3	10.5
Fees and other revenues not within the scope of revenue recognition guidance	9.5	13.9	12.5
Total fees and other revenues per consolidated statements of operations	18.1	23.2	23
Operating Segments | Specialty Benefits insurance | U.S. Insurance Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	14.8	14.9	14.8
Fees and other revenues not within the scope of revenue recognition guidance	19.3	19.6	20.6
Total fees and other revenues per consolidated statements of operations	34.1	34.5	35.4
Operating Segments | Individual Life insurance | U.S. Insurance Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	48.6	51.2	42.4
Fees and other revenues not within the scope of revenue recognition guidance	849.8	875.9	727
Total fees and other revenues per consolidated statements of operations	898.4	927.1	769.4
Operating Segments | U.S. Insurance Solutions Eliminations | U.S. Insurance Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total segment revenue from contracts with customers	(0.2)	(0.2)	(0.2)
Reconciling Items
Revenues from Contracts with Customers - Disaggregation of Revenues
Fees and other revenues not within the scope of revenue recognition guidance	1,733	1,791.4	1,614.4
Pre-tax other adjustments	$ 9.8	$ 8.5	$ 0.5

Revenues from Contracts with _4

Revenues from Contracts with Customers - Disaggregation within Segments (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from Contracts with Customers - Disaggregation of Revenues
Total fees and other revenues		$ 4,511.1	$ 4,409.9	$ 4,273.8
Premiums and other considerations		6,037.4	7,866.6	6,409.6
Net investment income (loss)		3,890.6	3,998.4	3,629.2
Retirement and Income Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Premiums and other considerations		3,221	4,862.7	3,635.9
Net investment income (loss)		2,457.9	2,420.4	2,195.2
Principal Global Investors
Revenues from Contracts with Customers - Disaggregation of Revenues
Net investment income (loss)		5.6	10.1	4.2
Principal International
Revenues from Contracts with Customers - Disaggregation of Revenues
Premiums and other considerations		156.6	393.3	317.2
Net investment income (loss)		446.8	575.9	494.9
U.S. Insurance Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Premiums and other considerations		2,659.8	2,610.6	2,456.5
Net investment income (loss)		850.6	854.5	815.1
Corporate
Revenues from Contracts with Customers - Disaggregation of Revenues
Net investment income (loss)		129.7	137.5	119.8
Operating Segments
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		2,768.3	2,610	2,658.9
Total operating revenues		14,579.9	16,393.1	14,424.8
Operating Segments | Retirement and Income Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		599.8	464.8	262.9
Total operating revenues		7,503.5	8,954.4	7,277
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Fee
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		591.2	455.5	252.4
Fees and other revenues not within the scope of revenue recognition guidance		1,130.4	1,139	1,132.9
Total fees and other revenues		1,721.6	1,594.5	1,385.3
Premiums and other considerations		5	3.5	4
Net investment income (loss)		423.2	405	394.4
Total operating revenues		2,149.8	2,003	1,783.7
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Fee | Administrative service fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		589.2	453.7	250.7
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Fee | Other fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		2	1.8	1.7
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Spread
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		8.6	9.3	10.5
Fees and other revenues not within the scope of revenue recognition guidance		9.5	13.9	12.5
Total fees and other revenues		18.1	23.2	23
Premiums and other considerations		3,216	4,859.2	3,631.9
Net investment income (loss)		2,119.6	2,069	1,838.4
Total operating revenues		5,353.7	6,951.4	5,493.3
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Spread | Deposit account fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		8.4	9.3	10.5
Operating Segments | Retirement and Income Solutions | Retirement and Income Solutions - Spread | Commission income
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		0.2
Operating Segments | Principal Global Investors
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		1,511.2	1,456.7	1,700.5
Fees and other revenues not within the scope of revenue recognition guidance		22.3	38.5	30.4
Total fees and other revenues		1,533.5	1,495.2	1,730.9
Net investment income (loss)		5.6	10.6	5.4
Total operating revenues		1,539.1	1,505.8	1,736.3
Operating Segments | Principal Global Investors | Management fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		1,298.4	1,239.1	1,244.5
Operating Segments | Principal Global Investors | Other fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		212.8	217.6	456
Performance fee recognized resulting from realignment of a real estate investment team	$ 253.1
Operating Segments | Principal International
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		439.2	462.2	477.1
Fees and other revenues not within the scope of revenue recognition guidance		5.6	6.3	7.3
Total fees and other revenues		444.8	468.5	484.4
Premiums and other considerations		156.6	393.3	317.2
Net investment income (loss)		495.4	661.4	571.3
Total operating revenues		1,096.8	1,523.2	1,372.9
Operating Segments | Principal International | Latin America
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		323.5	351.5	370.8
Operating Segments | Principal International | Asia
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		115.9	111	106.3
Operating Segments | Principal International | Principal International Corporate / Regional Office
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		0.9	0.9	0.9
Operating Segments | Principal International | Geographical Eliminations
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		(1.1)	(1.2)	(0.9)
Operating Segments | Principal International | Management fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		435.3	459.3	472.1
Operating Segments | Principal International | Other fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		3.9	2.9	5
Operating Segments | U.S. Insurance Solutions
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		63.2	65.9	57
Total operating revenues		4,480.2	4,449	4,089.8
Operating Segments | U.S. Insurance Solutions | Specialty Benefits insurance
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		14.8	14.9	14.8
Fees and other revenues not within the scope of revenue recognition guidance		19.3	19.6	20.6
Total fees and other revenues		34.1	34.5	35.4
Premiums and other considerations		2,330.7	2,292.7	2,134.1
Net investment income (loss)		160.6	166.4	156.9
Total operating revenues		2,525.4	2,493.6	2,326.4
Operating Segments | U.S. Insurance Solutions | Specialty Benefits insurance | Administrative service fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		14.8	14.9	14.8
Operating Segments | U.S. Insurance Solutions | Individual Life insurance
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		48.6	51.2	42.4
Fees and other revenues not within the scope of revenue recognition guidance		849.8	875.9	727
Total fees and other revenues		898.4	927.1	769.4
Premiums and other considerations		329.1	317.9	322.4
Net investment income (loss)		727.5	710.6	671.8
Total operating revenues		1,955	1,955.6	1,763.6
Operating Segments | U.S. Insurance Solutions | Individual Life insurance | Administrative service fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		21.8	24.3	22.8
Operating Segments | U.S. Insurance Solutions | Individual Life insurance | Commission income
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		26.8	26.9	19.6
Operating Segments | Corporate
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		154.9	160.4	161.4
Fees and other revenues not within the scope of revenue recognition guidance		(303.9)	(301.8)	(316.3)
Total fees and other revenues		(149)	(141.4)	(154.9)
Net investment income (loss)		109.3	102.1	103.7
Total operating revenues		(39.7)	(39.3)	(51.2)
Operating Segments | Corporate | Other fee revenue
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		59.1	46.1	35.4
Operating Segments | Corporate | Commission income
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		316.6	320.2	316.1
Operating Segments | Corporate | Revenue by type - Eliminations
Revenues from Contracts with Customers - Disaggregation of Revenues
Total revenues from contracts with customers		$ (220.8)	$ (205.9)	$ (190.1)

Revenues from Contracts with _5

Revenues from Contracts with Customers - Contract Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Contract costs
Contract cost asset	$ 173	$ 157
Practical expedient, incremental costs of obtaining a contract	true
Impairment loss for contract cost asset	$ 0	0	$ 0
Amortization expense of contract cost asset	$ 24.8	$ 24.4	$ 23.8

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans - Stock-Based Awards (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended			180 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	May 19, 2020	May 20, 2014
Stock-Based Compensation Plans
Stock-Based Compensation Plans - Disclosures
Compensation cost	$ 86.7	$ 78.7	$ 77.5
Related income tax benefit	17.1	16.8	16.7
Capitalized as part of an asset	$ 1.5	$ 1.7	$ 1.9
Amended and Restated 2010 Stock Incentive Plan and 2005 Directors Stock Plan
Stock-Based Compensation Plans - Disclosures
Number of shares that will be granted						0
2014 Directors Stock Plan
Stock-Based Compensation Plans - Disclosures
Number of shares that will be granted					0
Stock Incentive Plan and Directors Stock Plan
Stock-Based Compensation Plans - Disclosures
Options granted (in shares)				0
Awards or units granted (in shares)				0
2014 Stock Incentive Plan and 2020 Directors Stock Plan
Stock-Based Compensation Plans - Disclosures
Maximum number of new shares of common stock available for grant (in shares)	4			4

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans - Nonqualified Stock Options, Activity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
2014 Stock Incentive Plan, Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan
Stock-Based Compensation Plans - Disclosures
Option expiration period	10 years
Vesting period	3 years
Change in options outstanding
Options granted (in shares)	1.4	1.2	0.8
Nonqualified Stock Options
Change in options outstanding
Options outstanding at beginning of period (in shares)	5.3
Options granted (in shares)	1.4
Options exercised (in shares)	0.1
Options canceled (in shares)	0.1
Options outstanding at end of period (in shares)	6.5	5.3
Options vested or expected to vest at end of period (in shares)	6.5
Options exercisable at end of period (in shares)	4.2
Options outstanding at beginning of period, Weighted-average exercise price (in dollars per share)	$ 48.42
Options granted, Weighted-average exercise price (in dollars per share)	51.73
Options exercised, Weighted-average exercise price (in dollars per share)	29.56
Options canceled weighted-average exercise price (in dollars per share)	51.81
Options outstanding at end of period, Weighted-average exercise price (in dollars per share)	49.52	$ 48.42
Options vested or expected to vest at end of period, Weighted-average exercise price (in dollars per share)	49.52
Options exercisable at end of period, Weighted-average exercise price (in dollars per share)	$ 47.38
Options outstanding at end of period, Intrinsic value	$ 27.5
Options vested or expected to vest at end of period, Intrinsic value	27.5
Options exercisable at end of period, Intrinsic value	27.5
Total intrinsic value of options exercised	$ 3.4	$ 2.4	$ 18.7

Stock-Based Compensation Plan_4

Stock-Based Compensation Plans - Nonqualified Stock Options, Range of Exercise Prices (Details) - Nonqualified Stock Options - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Number of options outstanding (in shares)	6.5	5.3
Weighted-average remaining contractual life for stock options exercisable	6 years 1 month 6 days
Range of exercise prices, Range 1
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Lower limit of exercise price range (in dollars per share)	$ 27.46
Upper limit of exercise price range (in dollars per share)	$ 41.13
Number of options outstanding (in shares)	1.6
Weighted-average remaining contractual life	3 years 3 months 18 days
Range of exercise prices, Range 2
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Lower limit of exercise price range (in dollars per share)	$ 41.14
Upper limit of exercise price range (in dollars per share)	$ 51.53
Number of options outstanding (in shares)	1
Weighted-average remaining contractual life	3 years 8 months 12 days
Range of exercise prices, Range 3
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Lower limit of exercise price range (in dollars per share)	$ 51.54
Upper limit of exercise price range (in dollars per share)	$ 52.41
Number of options outstanding (in shares)	1.3
Weighted-average remaining contractual life	9 years 1 month 6 days
Range of exercise prices, Range 4
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Lower limit of exercise price range (in dollars per share)	$ 52.42
Upper limit of exercise price range (in dollars per share)	$ 62.75
Number of options outstanding (in shares)	1.2
Weighted-average remaining contractual life	8 years 1 month 6 days
Range of exercise prices, Range 5
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Lower limit of exercise price range (in dollars per share)	$ 62.76
Upper limit of exercise price range (in dollars per share)	$ 63.98
Number of options outstanding (in shares)	1.4
Weighted-average remaining contractual life	6 years 8 months 12 days
Range of exercise prices, Total Range
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices
Lower limit of exercise price range (in dollars per share)	$ 27.46
Upper limit of exercise price range (in dollars per share)	$ 63.98
Number of options outstanding (in shares)	6.5

Stock-Based Compensation Plan_5

Stock-Based Compensation Plans - Nonqualified Stock Options, Assumptions and Other Disclosures (Details) - Nonqualified Stock Options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assumptions used to estimate fair value of stock options granted during period
Weighted-average expected volatility (as a percent)	25.70%	23.30%	26.00%
Weighted-average expected term	7 years	7 years	7 years
Weighted-average risk-free interest rate (as a percent)	1.30%	2.60%	2.80%
Weighted-average expected dividend yield (as a percent)	4.33%	4.07%	3.19%
Weighted-average estimated fair value of stock options granted (in dollars per share)	$ 9.64	$ 10	$ 14.85
Other nonqualified stock option disclosures
Unrecognized compensation costs	$ 2.1
Weighted-average service period over which unrecognized compensation costs will be recognized	1 year 10 months 24 days
Cash received from stock options exercised	$ 4.4	$ 3.4	$ 29
Tax benefits realized for the tax deductions from options exercised	$ 1.4	$ 0.5	$ 3.9

Stock-Based Compensation Plan_6

Stock-Based Compensation Plans - Performance Share Awards and Restricted Stock Units (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Performance Share Awards
Stock-Based Compensation Plans - Disclosures
Performance period for goals	3 years
Change in nonvested units outstanding
Awards or units outstanding at beginning of period (in shares)	0.5
Awards or units granted (in shares)	0.3	0.2	0.2
Awards or units vested (in shares)	0.1
Awards or units outstanding at end of period (in shares)	0.7	0.5
Awards or units outstanding at beginning of period, Weighted-average grant-date fair value (in dollars per share)	$ 59.26
Awards or units granted, Weighted-average grant-date fair value (in dollars per share)	51.73	$ 53.09	$ 63.98
Awards or units vested, Weighted-average grant-date fair value (in dollars per share)	62.78
Awards or units outstanding at end of period, Weighted-average grant-date fair value (in dollars per share)	$ 55.28	$ 59.26
Other award and unit disclosures
Intrinsic value from awards or units vested	$ 8.7	$ 17.6	$ 21.5
Lower limit multiple of initial target awards (as a percent)	0.00%
Upper limit multiple of initial target awards (as a percent)	150.00%
Unrecognized compensation costs	$ 3
Weighted-average service period over which unrecognized compensation costs will be recognized	1 year 10 months 24 days
Tax benefits realized for the tax deductions from awards or units paid out	$ 3	$ 3.3	$ 3.3
Restricted Stock Units
Change in nonvested units outstanding
Awards or units outstanding at beginning of period (in shares)	2.6
Awards or units granted (in shares)	1.1	1.1	0.8
Awards or units vested (in shares)	0.8
Awards or units canceled (in shares)	0.1
Awards or units outstanding at end of period (in shares)	2.8	2.6
Awards or units outstanding at beginning of period, Weighted-average grant-date fair value (in dollars per share)	$ 59.15
Awards or units granted, Weighted-average grant-date fair value (in dollars per share)	50.49	$ 53.17	$ 63.68
Awards or units vested, Weighted-average grant-date fair value (in dollars per share)	62.32
Awards or units canceled, Weighted-average grant-date fair value (in dollars per share)	55.68
Awards or units outstanding at end of period, Weighted-average grant-date fair value (in dollars per share)	$ 54.86	$ 59.15
Other award and unit disclosures
Intrinsic value from awards or units vested	$ 41.2	$ 64	$ 51.1
Unrecognized compensation costs	$ 43.4
Weighted-average service period over which unrecognized compensation costs will be recognized	1 year 8 months 12 days
Tax benefits realized for the tax deductions from awards or units paid out	$ 14.6	$ 13.2	$ 10.8
2014 Stock Incentive Plan, Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan
Other award and unit disclosures
Vesting period	3 years
2014 Stock Incentive Plan, Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan | Restricted Stock Units
Other award and unit disclosures
Vesting period	3 years
2020 Directors Stock Plan, 2014 Directors Stock Plan and 2005 Directors Stock Plan | Restricted Stock Units
Other award and unit disclosures
Vesting period	1 year

Stock-Based Compensation Plan_7

Stock-Based Compensation Plans - Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan - USD ($) $ / shares in Units, shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock-Based Compensation Plans - Disclosures
Maximum value of company common stock that can be purchased by an employee per year	$ 25,000
Employee purchase price as a percent of fair market value (as a percent)	85.00%
Share purchases under employee stock purchase plan (in shares)	1.4	0.9	0.7
Weighted-average fair value of discount on employee stock purchase plan (in dollars per share)	$ 11.33	$ 11.37	$ 9.27
Intrinsic value from shares settled	$ 15,500,000	$ 9,700,000	$ 6,100,000
Cash received from shares issued	37,800,000	36,200,000	30,100,000
Tax benefits realized from the settlement of share-based payment arrangements	$ 900,000	$ 900,000	$ 700,000
Shares available to be issued under employee stock purchase plan (in shares)	5

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income (loss)	$ 491.5	$ 235.9	$ 416.1	$ 285	$ 315.3	$ 284.6	$ 392.1	$ 452.1	$ 1,428.5	$ 1,444.1	$ 1,553.7
Subtract:
Net income (loss) attributable to noncontrolling interest									32.7	49.9	7.2
Total									$ 1,395.8	$ 1,394.2	$ 1,546.5
Weighted-average shares outstanding:
Basic									274.7	278.6	285.8
Dilutive effects:
Diluted									276.6	281	288.8
Net income (loss) per common share:
Basic	$ 1.72	$ 0.86	$ 1.45	$ 1.05	$ 1.08	$ 0.99	$ 1.38	$ 1.54	$ 5.08	$ 5	$ 5.41
Diluted	$ 1.70	$ 0.85	$ 1.45	$ 1.04	$ 1.07	$ 0.98	$ 1.37	$ 1.53	$ 5.05	$ 4.96	$ 5.36
Nonqualified Stock Options
Dilutive effects:
Stock-based compensation awards									0.3	0.9	1
Restricted Stock Units
Dilutive effects:
Stock-based compensation awards									1.5	1.4	1.7
Performance Share Awards
Dilutive effects:
Stock-based compensation awards									0.1	0.1	0.3

Quarterly Results of Operatio_3

Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Results of Operations (Unaudited)
Total revenues	$ 3,765.1	$ 3,310.7	$ 3,114.6	$ 4,551.3	$ 4,047.2	$ 4,458.4	$ 3,972.6	$ 3,743.9	$ 14,741.7	$ 16,222.1	$ 14,237.2
Total expenses	3,173.5	3,035.6	2,616	4,223.1	3,675.9	4,112.7	3,522.3	3,217.9	13,048.2	14,528.8	12,452.8
Net income (loss)	491.5	235.9	416.1	285	315.3	284.6	392.1	452.1	1,428.5	1,444.1	1,553.7
Net income attributable to PFG	$ 472.6	$ 236	$ 398.3	$ 288.9	$ 300.9	$ 277.1	$ 386.3	$ 429.9	$ 1,395.8	$ 1,394.2	$ 1,546.5
Basic earnings per common share (in dollars per share)	$ 1.72	$ 0.86	$ 1.45	$ 1.05	$ 1.08	$ 0.99	$ 1.38	$ 1.54	$ 5.08	$ 5	$ 5.41
Diluted earnings per common share (in dollars per share)	$ 1.70	$ 0.85	$ 1.45	$ 1.04	$ 1.07	$ 0.98	$ 1.37	$ 1.53	$ 5.05	$ 4.96	$ 5.36

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Fixed maturities, available-for-sale	$ 78,710.3	$ 70,106.2
Fixed maturities, trading	532.1	675.9
Equity securities	2,013.4	1,879.4
Mortgage loans	17,343	16,486.9
Real estate	1,797.3	1,714.8
Policy loans	784	798
Investment in unconsolidated entities	842.7	830.2
Other investments	4,284.1	3,860
Cash and cash equivalents	2,849.8	2,515.9
Accrued investment income	710.6	686.6
Premiums due and other receivables	1,723.8	1,740.3
Deferred acquisition costs	3,409.7	3,521.3	$ 3,693.5	$ 3,540.7
Property and equipment	1,019	967.7
Goodwill	1,711	1,693.8	1,100
Other intangibles	1,723	1,786.7
Separate account assets	175,951.4	165,468
Other assets	1,222.5	1,356.1
Total assets	296,627.7	276,087.8
Liabilities
Contractholder funds	43,237.7	41,367.5
Future policy benefits and claims	45,207.2	40,838.2
Other policyholder funds	1,059.4	959.4
Short-term debt	84.7	93.4
Long-term debt	4,279.2	3,734.1
Income taxes currently payable	22.3	16.2
Deferred income taxes	2,330.8	1,796.6
Separate account liabilities	175,951.4	165,468
Other liabilities	7,582.1	6,863.7
Total liabilities	279,754.8	261,137.1
Redeemable noncontrolling interest	255.6	264.9	391.2	101.3
Stockholders' equity
Common stock	4.8	4.8
Additional paid-in capital	10,321.6	10,182.6
Retained earnings	11,838	11,074.3
Accumulated other comprehensive income	2,383.1	1,037.9
Treasury stock, at cost	(7,988.6)	(7,681.6)
Total stockholders' equity attributable to Principal Financial Group, Inc.	16,558.9	14,618
Noncontrolling interest	58.4	67.8
Total stockholders' equity	16,617.3	14,685.8	$ 11,456	$ 12,921.9
Total liabilities and stockholders' equity	296,627.7	276,087.8
Principal Financial Group, Inc. parent only | Legal Entities
Assets
Fixed maturities, available-for-sale	813.2	265.8
Fixed maturities, trading	178.8	268.2
Investment in unconsolidated entities	19,714.3	17,539.6
Other investments	63.7	10.4
Cash and cash equivalents	302.4	394.9
Accrued investment income	2.3	1.6
Other assets	408.1	383.2
Total assets	21,482.8	18,863.7
Liabilities
Long-term debt	4,223.3	3,625.5
Other liabilities	700.6	620.2
Total liabilities	4,923.9	4,245.7
Stockholders' equity
Common stock	4.8	4.8
Additional paid-in capital	10,321.6	10,182.6
Retained earnings	11,838	11,074.3
Accumulated other comprehensive income	2,383.1	1,037.9
Treasury stock, at cost	(7,988.6)	(7,681.6)
Total stockholders' equity attributable to Principal Financial Group, Inc.	16,558.9	14,618
Total stockholders' equity	16,558.9	14,618
Total liabilities and stockholders' equity	21,482.8	18,863.7
Principal Financial Services, Inc. only | Legal Entities
Assets
Equity securities	42.9	41.4
Investment in unconsolidated entities	18,557.9	16,664.1
Other investments	156.3	251.9
Cash and cash equivalents	819.1	598.4
Accrued investment income	0.2	0.4
Premiums due and other receivables	88.8	100
Goodwill	618.5	618.5
Other intangibles	503.6	531.7
Other assets	58	35.2
Total assets	20,845.3	18,841.6
Liabilities
Long-term debt	274.9	320.7
Deferred income taxes	31.3	5.9
Other liabilities	973.2	1,113.6
Total liabilities	1,279.4	1,440.2
Stockholders' equity
Additional paid-in capital	9,738.4	9,658.3
Retained earnings	6,980.7	6,263.5
Accumulated other comprehensive income	2,846.8	1,479.6
Total stockholders' equity attributable to Principal Financial Group, Inc.	19,565.9	17,401.4
Total stockholders' equity	19,565.9	17,401.4
Total liabilities and stockholders' equity	20,845.3	18,841.6
Principal Life Insurance Company and other subsidiaries combined | Legal Entities
Assets
Fixed maturities, available-for-sale	77,897.1	69,840.4
Fixed maturities, trading	353.3	407.7
Equity securities	1,970.5	1,838
Mortgage loans	17,343	16,486.9
Real estate	1,797.3	1,714.8
Policy loans	784	798
Investment in unconsolidated entities	615.9	649.4
Other investments	4,064.1	3,597.7
Cash and cash equivalents	2,740.7	2,656.2
Accrued investment income	708.1	684.6
Premiums due and other receivables	1,910.2	1,961.1
Deferred acquisition costs	3,409.7	3,521.3
Property and equipment	1,019	967.7
Goodwill	1,092.5	1,075.3
Other intangibles	1,219.4	1,255
Separate account assets	175,951.4	165,468
Other assets	1,362.7	1,509.5
Total assets	294,238.9	274,431.6
Liabilities
Contractholder funds	43,237.7	41,367.5
Future policy benefits and claims	45,207.2	40,838.2
Other policyholder funds	1,059.4	959.4
Short-term debt	84.7	93.4
Long-term debt	55.9	108.7
Income taxes currently payable	79.7	66.4
Deferred income taxes	2,824.4	2,285.8
Separate account liabilities	175,951.4	165,468
Other liabilities	6,769.6	6,104.7
Total liabilities	275,270	257,292.1
Redeemable noncontrolling interest	255.6	264.9
Stockholders' equity
Common stock	5.5	11
Additional paid-in capital	12,357.7	12,157.9
Retained earnings	3,285.9	2,985.1
Accumulated other comprehensive income	3,005.8	1,654.8
Treasury stock, at cost		(2)
Total stockholders' equity attributable to Principal Financial Group, Inc.	18,654.9	16,806.8
Noncontrolling interest	58.4	67.8
Total stockholders' equity	18,713.3	16,874.6
Total liabilities and stockholders' equity	294,238.9	274,431.6
Principal Life Insurance Company and other subsidiaries combined | Legal Entities | Nonqualified benefit plans
Stockholders' equity
Assets held in Rabbi trusts	801.7	731.9
Liabilities held in Rabbi trusts	653.3	593.7
Eliminations, Shelf Registration Debt Guarantor | Eliminations
Assets
Investment in unconsolidated entities	(38,045.4)	(34,022.9)
Cash and cash equivalents	(1,012.4)	(1,133.6)
Premiums due and other receivables	(275.2)	(320.8)
Other assets	(606.3)	(571.8)
Total assets	(39,939.3)	(36,049.1)
Liabilities
Long-term debt	(274.9)	(320.8)
Income taxes currently payable	(57.4)	(50.2)
Deferred income taxes	(524.9)	(495.1)
Other liabilities	(861.3)	(974.8)
Total liabilities	(1,718.5)	(1,840.9)
Stockholders' equity
Common stock	(5.5)	(11)
Additional paid-in capital	(22,096.1)	(21,816.2)
Retained earnings	(10,266.6)	(9,248.6)
Accumulated other comprehensive income	(5,852.6)	(3,134.4)
Treasury stock, at cost		2
Total stockholders' equity attributable to Principal Financial Group, Inc.	(38,220.8)	(34,208.2)
Total stockholders' equity	(38,220.8)	(34,208.2)
Total liabilities and stockholders' equity	$ (39,939.3)	$ (36,049.1)

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Premiums and other considerations									$ 6,037.4	$ 7,866.6	$ 6,409.6
Fees and other revenues									4,511.1	4,409.9	4,273.8
Net investment income (loss)									3,890.6	3,998.4	3,629.2
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities										(9.3)	(46.3)
Net other-than-temporary impairment (losses) recoveries on available-for-sale securities										(38.3)	10.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income										(5.2)	(39.7)
Net impairment (losses) recoveries on available-for-sale securities										(43.5)	(29.1)
Net realized capital gains (losses)									302.6	(52.8)	(75.4)
Total revenues	$ 3,765.1	$ 3,310.7	$ 3,114.6	$ 4,551.3	$ 4,047.2	$ 4,458.4	$ 3,972.6	$ 3,743.9	14,741.7	16,222.1	14,237.2
Expenses
Benefits, claims and settlement expenses									8,281.5	9,905.8	8,192.5
Dividends to policyholders									120.2	119.1	123.6
Operating expenses									4,646.5	4,503.9	4,136.7
Total expenses	3,173.5	3,035.6	2,616	4,223.1	3,675.9	4,112.7	3,522.3	3,217.9	13,048.2	14,528.8	12,452.8
Income (loss) before income taxes									1,693.5	1,693.3	1,784.4
Income taxes (benefits)									265	249.2	230.7
Net income (loss)	491.5	235.9	416.1	285	315.3	284.6	392.1	452.1	1,428.5	1,444.1	1,553.7
Net income attributable to noncontrolling interest									32.7	49.9	7.2
Net income attributable to PFG	472.6	236	398.3	288.9	300.9	277.1	386.3	429.9	1,395.8	1,394.2	1,546.5
Net income (loss)	$ 491.5	$ 235.9	$ 416.1	$ 285	$ 315.3	$ 284.6	$ 392.1	$ 452.1	1,428.5	1,444.1	1,553.7
Other comprehensive income									1,347	2,606.7	(1,835.7)
Comprehensive income (loss)									2,775.5	4,050.8	(282)
Principal Financial Group, Inc. parent only | Legal Entities
Revenues
Net investment income (loss)									13.3	19.4	25.8
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities										12.3	(8.2)
Net realized capital gains (losses)									7	12.3	(8.2)
Total revenues									20.3	31.7	17.6
Expenses
Operating expenses									200	210.9	191.9
Total expenses									200	210.9	191.9
Income (loss) before income taxes									(179.7)	(179.2)	(174.3)
Income taxes (benefits)									(46.1)	(44.2)	(62.5)
Equity in the net income (loss) of subsidiaries									1,529.4	1,529.2	1,658.3
Net income (loss)									1,395.8	1,394.2	1,546.5
Net income attributable to PFG									1,395.8	1,394.2	1,546.5
Net income (loss)									1,395.8	1,394.2	1,546.5
Other comprehensive income									1,206.5	2,570.9	(1,824.5)
Comprehensive income (loss)									2,602.3	3,965.1	(278)
Principal Financial Services, Inc. only | Legal Entities
Revenues
Fees and other revenues									341.3	205.9	2.7
Net investment income (loss)									(1.4)	(6.5)	(6.7)
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities										17.5	(3.5)
Net realized capital gains (losses)									32.8	17.5	(3.5)
Total revenues									372.7	216.9	(7.5)
Expenses
Operating expenses									548.7	368.2	29.1
Total expenses									548.7	368.2	29.1
Income (loss) before income taxes									(176)	(151.3)	(36.6)
Income taxes (benefits)									(45.8)	(11.8)	0.2
Equity in the net income (loss) of subsidiaries									1,649.4	1,659.7	1,684.5
Net income (loss)									1,519.2	1,520.2	1,647.7
Net income attributable to PFG									1,519.2	1,520.2	1,647.7
Net income (loss)									1,519.2	1,520.2	1,647.7
Other comprehensive income									1,228.6	2,530.9	(1,839.1)
Comprehensive income (loss)									2,747.8	4,051.1	(191.4)
Principal Life Insurance Company and other subsidiaries combined | Legal Entities
Revenues
Premiums and other considerations									6,037.4	7,866.6	6,409.6
Fees and other revenues									4,182.9	4,215.5	4,286.4
Net investment income (loss)									3,867.1	3,975.1	3,598
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities										(38.9)	(34.6)
Net other-than-temporary impairment (losses) recoveries on available-for-sale securities										(38.3)	10.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income										(5.2)	(39.7)
Net impairment (losses) recoveries on available-for-sale securities										(43.5)	(29.1)
Net realized capital gains (losses)									262.9	(82.4)	(63.7)
Total revenues									14,350.3	15,974.8	14,230.3
Expenses
Benefits, claims and settlement expenses									8,281.5	9,905.8	8,192.5
Dividends to policyholders									120.2	119.1	123.6
Operating expenses									3,909.6	3,935.1	3,929.5
Total expenses									12,311.3	13,960	12,245.6
Income (loss) before income taxes									2,039	2,014.8	1,984.7
Income taxes (benefits)									356.9	305.2	293
Net income (loss)									1,682.1	1,709.6	1,691.7
Net income attributable to noncontrolling interest									32.7	49.9	7.2
Net income attributable to PFG									1,649.4	1,659.7	1,684.5
Net income (loss)									1,682.1	1,709.6	1,691.7
Other comprehensive income									1,352.7	2,562.2	(1,856.4)
Comprehensive income (loss)									3,034.8	4,271.8	(164.7)
Eliminations, Shelf Registration Debt Guarantor | Eliminations
Revenues
Fees and other revenues									(13.1)	(11.5)	(15.3)
Net investment income (loss)									11.6	10.4	12.1
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities										(0.2)
Net realized capital gains (losses)									(0.1)	(0.2)
Total revenues									(1.6)	(1.3)	(3.2)
Expenses
Operating expenses									(11.8)	(10.3)	(13.8)
Total expenses									(11.8)	(10.3)	(13.8)
Income (loss) before income taxes									10.2	9	10.6
Equity in the net income (loss) of subsidiaries									(3,178.8)	(3,188.9)	(3,342.8)
Net income (loss)									(3,168.6)	(3,179.9)	(3,332.2)
Net income attributable to PFG									(3,168.6)	(3,179.9)	(3,332.2)
Net income (loss)									(3,168.6)	(3,179.9)	(3,332.2)
Other comprehensive income									(2,440.8)	(5,057.3)	3,684.3
Comprehensive income (loss)									$ (5,609.4)	$ (8,237.2)	$ 352.1

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information - Shelf Registration Guarantor, Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net cash provided by (used in) operating activities	$ 3,738.6	$ 5,493.2	$ 5,156.5
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases	(15,713.4)	(14,137.1)	(13,909.8)
Fixed maturities available-for-sale and equity securities with intent to hold: Sales	3,043.9	2,397.4	3,813.1
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities	8,819.5	7,064.2	6,217.6
Mortgage loans acquired or originated	(3,249.5)	(3,487.7)	(3,447.5)
Mortgage loans sold or repaid	2,477.2	2,335.9	2,228.4
Real estate acquired	(230.6)	(127.5)	(88.1)
Real estate sold	2.3	96.3	63.5
Net (purchases) sales of property and equipment	(108.8)	(132.4)	(92.3)
Purchase of business or interests in subsidiaries, net of cash acquired		(1,208.5)	(184.7)
Net change in other investments	(66.4)	(489.1)	(302.7)
Net cash provided by (used in) investing activities	(5,025.8)	(7,688.5)	(5,702.5)
Financing activities
Issuance of common stock	42.8	37.7	64
Acquisition of treasury stock	(307)	(281)	(671.6)
Payments for financing element derivatives	(30.9)	(26.9)	(65.9)
Purchase of subsidiary shares from noncontrolling interest	(1.4)	(1.7)	(31.1)
Dividends to common stockholders	(614.5)	(606)	(598.6)
Issuance of long-term debt	608.9	504.9	80.8
Principal repayments of long-term debt	(65.8)	(32.2)	(1.3)
Net proceeds from short-term borrowings	(12.6)	57.5	8.5
Investment contract deposits	10,284.4	9,200	8,308.8
Investment contract withdrawals	(8,852.7)	(7,747.7)	(6,589.6)
Net increase (decrease) in banking operation deposits	569.7	623.4	553
Other	0.2	5.7	(4.3)
Net cash provided by (used in) financing activities	1,621.1	1,733.7	1,052.7
Net increase (decrease) in cash and cash equivalents	333.9	(461.6)	506.7
Cash and cash equivalents at beginning of period	2,515.9	2,977.5	2,470.8
Cash and cash equivalents at end of period	2,849.8	2,515.9	2,977.5
Principal Financial Group, Inc. parent only | Legal Entities
Operating activities
Net cash provided by (used in) operating activities	(15.2)	7.1	(132.4)
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases	(736.5)	(251.5)	(210.9)
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities	193.7	200	2.3
Net (purchases) sales of property and equipment	(0.1)	(0.1)	(0.1)
Dividends and returns of capital received from unconsolidated entities	799.1	494.2	1,041.6
Net change in other investments	(50)	(34)	(2.2)
Net cash provided by (used in) investing activities	206.2	408.6	830.7
Financing activities
Issuance of common stock	42.8	37.7	64
Acquisition of treasury stock	(307)	(281)	(671.6)
Dividends to common stockholders	(614.5)	(606)	(598.6)
Issuance of long-term debt	595.2	493.6
Net cash provided by (used in) financing activities	(283.5)	(355.7)	(1,206.2)
Net increase (decrease) in cash and cash equivalents	(92.5)	60	(507.9)
Cash and cash equivalents at beginning of period	394.9	334.9	842.8
Cash and cash equivalents at end of period	302.4	394.9	334.9
Principal Financial Services, Inc. only | Legal Entities
Operating activities
Net cash provided by (used in) operating activities	1,490.5	(54.7)	696.3
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases		(0.2)
Fixed maturities available-for-sale and equity securities with intent to hold: Sales		0.2
Net (purchases) sales of property and equipment	(3.5)	(2)
Purchase of business or interests in subsidiaries, net of cash acquired		(1,209.6)
Dividends and returns of capital received from unconsolidated entities	1,189.2	2,118.7	589.1
Net change in other investments	(1,610.4)	(362.9)	(166.2)
Net cash provided by (used in) investing activities	(424.7)	544.2	422.9
Financing activities
Issuance of long-term debt	8.5	10	11.1
Principal repayments of long-term debt	(54.5)	(55.9)	(57.1)
Dividends and capital received from (dividends and capital paid to) parent	(799.1)	(494.2)	(1,041.6)
Net cash provided by (used in) financing activities	(845.1)	(540.1)	(1,087.6)
Net increase (decrease) in cash and cash equivalents	220.7	(50.6)	31.6
Cash and cash equivalents at beginning of period	598.4	649	617.4
Cash and cash equivalents at end of period	819.1	598.4	649
Principal Life Insurance Company and other subsidiaries combined | Legal Entities
Operating activities
Net cash provided by (used in) operating activities	4,014.8	5,760.7	5,030.9
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases	(14,976.9)	(13,885.4)	(13,698.9)
Fixed maturities available-for-sale and equity securities with intent to hold: Sales	3,043.9	2,397.2	3,813.1
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities	8,625.8	6,864.2	6,215.3
Mortgage loans acquired or originated	(3,249.5)	(3,487.7)	(3,447.5)
Mortgage loans sold or repaid	2,477.2	2,335.9	2,228.4
Real estate acquired	(230.6)	(127.5)	(88.1)
Real estate sold	2.3	96.3	63.5
Net (purchases) sales of property and equipment	(105.2)	(130.3)	(92.2)
Purchase of business or interests in subsidiaries, net of cash acquired		1.1	(184.7)
Net change in other investments	(232.7)	(235.8)	(413.9)
Net cash provided by (used in) investing activities	(4,645.7)	(6,172)	(5,605)
Financing activities
Payments for financing element derivatives	(30.9)	(26.9)	(65.9)
Purchase of subsidiary shares from noncontrolling interest	(1.4)	(1.7)	(31.1)
Issuance of long-term debt	13.7	11.3	80.8
Principal repayments of long-term debt	(65.8)	(32.2)	(1.3)
Net proceeds from short-term borrowings	(12.6)	57.5	8.5
Dividends and capital received from (dividends and capital paid to) parent	(1,189.2)	(2,118.7)	(589.1)
Investment contract deposits	10,284.4	9,200	8,308.8
Investment contract withdrawals	(8,852.7)	(7,747.7)	(6,589.6)
Net increase (decrease) in banking operation deposits	569.7	623.4	553
Other	0.2	5.7	(4.3)
Net cash provided by (used in) financing activities	715.4	(29.3)	1,669.8
Net increase (decrease) in cash and cash equivalents	84.5	(440.6)	1,095.7
Cash and cash equivalents at beginning of period	2,656.2	3,096.8	2,001.1
Cash and cash equivalents at end of period	2,740.7	2,656.2	3,096.8
Eliminations, Shelf Registration Debt Guarantor | Eliminations
Operating activities
Net cash provided by (used in) operating activities	(1,751.5)	(219.9)	(438.3)
Investing activities
Dividends and returns of capital received from unconsolidated entities	(1,988.3)	(2,612.9)	(1,630.7)
Net change in other investments	1,826.7	143.6	279.6
Net cash provided by (used in) investing activities	(161.6)	(2,469.3)	(1,351.1)
Financing activities
Issuance of long-term debt	(8.5)	(10)	(11.1)
Principal repayments of long-term debt	54.5	55.9	57.1
Dividends and capital received from (dividends and capital paid to) parent	1,988.3	2,612.9	1,630.7
Net cash provided by (used in) financing activities	2,034.3	2,658.8	1,676.7
Net increase (decrease) in cash and cash equivalents	121.2	(30.4)	(112.7)
Cash and cash equivalents at beginning of period	(1,133.6)	(1,103.2)	(990.5)
Cash and cash equivalents at end of period	$ (1,012.4)	$ (1,133.6)	$ (1,103.2)

Schedule I - Summary of Inves_2

Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details) $ in Millions	Dec. 31, 2020USD ($)
Summary of Investments - Other Than Investments in Related Parties
Cost	$ 98,143.4
Amount as shown in the Consolidated Statement of Financial Position	106,306.9
Fixed maturities | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	70,546.8
Value	78,710.3
Amount as shown in the Consolidated Statement of Financial Position	78,710.3
Fixed maturities | Trading
Summary of Investments - Other Than Investments in Related Parties
Cost	532.1
Value	532.1
Amount as shown in the Consolidated Statement of Financial Position	532.1
U.S. government and agencies | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	1,893.1
Value	2,111.5
Amount as shown in the Consolidated Statement of Financial Position	2,111.5
States and political subdivisions | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	8,004.9
Value	9,167.8
Amount as shown in the Consolidated Statement of Financial Position	9,167.8
Non-U.S. governments | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	881.6
Value	1,073.7
Amount as shown in the Consolidated Statement of Financial Position	1,073.7
Public utilities | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	5,375.6
Value	6,114.3
Amount as shown in the Consolidated Statement of Financial Position	6,114.3
Redeemable preferred stock | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	19.3
Value	20.8
Amount as shown in the Consolidated Statement of Financial Position	20.8
All other corporate bonds | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	35,895
Value	41,219.7
Amount as shown in the Consolidated Statement of Financial Position	41,219.7
Residential mortgage-backed pass-through securities | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	2,857.6
Value	2,986.8
Amount as shown in the Consolidated Statement of Financial Position	2,986.8
Commercial mortgage-backed securities | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	4,741.2
Value	4,942.3
Amount as shown in the Consolidated Statement of Financial Position	4,942.3
Collateralized debt obligations | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	4,045.9
Value	4,027.5
Amount as shown in the Consolidated Statement of Financial Position	4,027.5
Other debt obligations | Available-for-sale
Summary of Investments - Other Than Investments in Related Parties
Cost	6,832.6
Value	7,045.9
Amount as shown in the Consolidated Statement of Financial Position	7,045.9
Equity securities
Summary of Investments - Other Than Investments in Related Parties
Cost	2,013.4
Value	2,013.4
Amount as shown in the Consolidated Statement of Financial Position	2,013.4
Common stocks: Banks, trust and insurance companies
Summary of Investments - Other Than Investments in Related Parties
Cost	483.4
Value	483.4
Amount as shown in the Consolidated Statement of Financial Position	483.4
Common stocks: Public Utilities
Summary of Investments - Other Than Investments in Related Parties
Cost	6.8
Value	6.8
Amount as shown in the Consolidated Statement of Financial Position	6.8
Common stocks: Industrial, miscellaneous and all other
Summary of Investments - Other Than Investments in Related Parties
Cost	874.6
Value	874.6
Amount as shown in the Consolidated Statement of Financial Position	874.6
Other corporate
Summary of Investments - Other Than Investments in Related Parties
Cost	499.7
Value	499.7
Amount as shown in the Consolidated Statement of Financial Position	499.7
Non-redeemable preferred stock
Summary of Investments - Other Than Investments in Related Parties
Cost	148.9
Value	148.9
Amount as shown in the Consolidated Statement of Financial Position	148.9
Mortgage loans
Summary of Investments - Other Than Investments in Related Parties
Cost	17,343
Amount as shown in the Consolidated Statement of Financial Position	17,343
Real estate acquired in satisfaction of debt
Summary of Investments - Other Than Investments in Related Parties
Cost	1.2
Amount as shown in the Consolidated Statement of Financial Position	1.2
Other real estate
Summary of Investments - Other Than Investments in Related Parties
Cost	1,796.1
Amount as shown in the Consolidated Statement of Financial Position	1,796.1
Policy loans
Summary of Investments - Other Than Investments in Related Parties
Cost	784
Amount as shown in the Consolidated Statement of Financial Position	784
Investments: Other investments
Summary of Investments - Other Than Investments in Related Parties
Cost	5,126.8
Amount as shown in the Consolidated Statement of Financial Position	$ 5,126.8

Schedule II - Condensed Finan_2

Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Fixed maturities, available-for-sale	$ 78,710.3	$ 70,106.2
Fixed maturities, trading	532.1	675.9
Other investments	5,126.8	4,690.2
Cash and cash equivalents	2,849.8	2,515.9
Deferred income taxes	113.8	123.6
Investment in unconsolidated entities	842.7	830.2
Total assets	296,627.7	276,087.8
Liabilities
Long-term debt	4,279.2	3,734.1
Total liabilities	279,754.8	261,137.1
Stockholders' equity
Common stock, par value $0.01 per share; 2,500 million shares authorized; 481.9 million and 479.3 million shares issued as of 2020 and 2019; 273.3 million and 276.6 million shares outstanding as of 2020 and 2019	4.8	4.8
Additional paid-in capital	10,321.6	10,182.6
Retained earnings (accumulated deficit)	11,838	11,074.3
Accumulated other comprehensive income (loss)	2,383.1	1,037.9
Treasury stock, at cost (208.6 million and 202.7 million shares as of 2020 and 2019)	(7,988.6)	(7,681.6)
Total stockholders' equity attributable to Principal Financial Group, Inc.	16,558.9	14,618
Total liabilities and stockholders' equity	296,627.7	276,087.8
Principal Financial Group, Inc. parent only | Legal Entities
Assets
Fixed maturities, available-for-sale	813.2	265.8
Fixed maturities, trading	178.8	268.2
Other investments	63.7	10.4
Cash and cash equivalents	302.4	394.9
Income taxes receivable	7.4	11.1
Deferred income taxes	371.2	344.4
Amounts receivable from subsidiaries	4.7	3.8
Other assets	27.1	25.5
Investment in unconsolidated entities	19,714.3	17,539.6
Total assets	21,482.8	18,863.7
Liabilities
Long-term debt	4,223.3	3,625.5
Accrued investment payable	25.3	25.4
Pension liability	668.9	590.6
Other liabilities	6.4	4.2
Total liabilities	4,923.9	4,245.7
Stockholders' equity
Common stock, par value $0.01 per share; 2,500 million shares authorized; 481.9 million and 479.3 million shares issued as of 2020 and 2019; 273.3 million and 276.6 million shares outstanding as of 2020 and 2019	4.8	4.8
Additional paid-in capital	10,321.6	10,182.6
Retained earnings (accumulated deficit)	11,838	11,074.3
Accumulated other comprehensive income (loss)	2,383.1	1,037.9
Treasury stock, at cost (208.6 million and 202.7 million shares as of 2020 and 2019)	(7,988.6)	(7,681.6)
Total stockholders' equity attributable to Principal Financial Group, Inc.	16,558.9	14,618
Total liabilities and stockholders' equity	$ 21,482.8	$ 18,863.7

Schedule II - Condensed Finan_3

Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Financial Position - Parenthetical (Details) - $ / shares shares in Millions	Dec. 31, 2020	Dec. 31, 2019
Condensed Financial Statements, Captions [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	2,500	2,500
Common stock, issued (in shares)	481.9	479.3
Common stock, outstanding (in shares)	273.3	276.6
Treasury stock (in shares)	208.6	202.7
Principal Financial Group, Inc. parent only | Legal Entities
Condensed Financial Statements, Captions [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	2,500	2,500
Common stock, issued (in shares)	481.9	479.3
Common stock, outstanding (in shares)	273.3	276.6
Treasury stock (in shares)	208.6	202.7

Schedule II - Condensed Finan_4

Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Net investment income (loss)									$ 3,890.6	$ 3,998.4	$ 3,629.2
Net realized capital gains (losses)									302.6	(52.8)	(75.4)
Total revenues	$ 3,765.1	$ 3,310.7	$ 3,114.6	$ 4,551.3	$ 4,047.2	$ 4,458.4	$ 3,972.6	$ 3,743.9	14,741.7	16,222.1	14,237.2
Expenses
Other operating costs and expenses									4,646.5	4,503.9	4,136.7
Total expenses	3,173.5	3,035.6	2,616	4,223.1	3,675.9	4,112.7	3,522.3	3,217.9	13,048.2	14,528.8	12,452.8
Loss before income taxes									1,693.5	1,693.3	1,784.4
Income taxes (benefits)									265	249.2	230.7
Net income (loss) attributable to Principal Financial Group, Inc.	$ 472.6	$ 236	$ 398.3	$ 288.9	$ 300.9	$ 277.1	$ 386.3	$ 429.9	1,395.8	1,394.2	1,546.5
Principal Financial Group, Inc. parent only | Legal Entities
Revenues
Net investment income (loss)									13.3	19.4	25.8
Net realized capital gains (losses)									7	12.3	(8.2)
Total revenues									20.3	31.7	17.6
Expenses
Other operating costs and expenses									200	210.9	191.9
Total expenses									200	210.9	191.9
Loss before income taxes									(179.7)	(179.2)	(174.3)
Income taxes (benefits)									(46.1)	(44.2)	(62.5)
Equity in the net income (loss) of subsidiaries									1,529.4	1,529.2	1,658.3
Net income (loss) attributable to Principal Financial Group, Inc.									$ 1,395.8	$ 1,394.2	$ 1,546.5

Schedule II - Condensed Finan_5

Schedule II - Condensed Financial Information of Registrant (Parent Only) - Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net income (loss)	$ 491.5	$ 235.9	$ 416.1	$ 285	$ 315.3	$ 284.6	$ 392.1	$ 452.1	$ 1,428.5	$ 1,444.1	$ 1,553.7
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Net realized capital (gains) losses									(302.6)	52.8	75.4
Stock-based compensation									87.6	82.6	77.4
Changes in:
Net cash flows for trading securities and equity securities with operating intent									144.2	(53.8)	(133.7)
Current and deferred income taxes (benefits)									442.5	211.2	274.7
Other									110.4	11.1	(35.7)
Net cash provided by (used in) operating activities									3,738.6	5,493.2	5,156.5
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases									(15,713.4)	(14,137.1)	(13,909.8)
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities									8,819.5	7,064.2	6,217.6
Net (purchases) sales of property and equipment									(108.8)	(132.4)	(92.3)
Net change in other investments									(66.4)	(489.1)	(302.7)
Net cash provided by (used in) investing activities									(5,025.8)	(7,688.5)	(5,702.5)
Financing activities
Issuance of common stock									42.8	37.7	64
Acquisition of treasury stock									(307)	(281)	(671.6)
Dividends to common stockholders									(614.5)	(606)	(598.6)
Principal repayments of long-term debt									(65.8)	(32.2)	(1.3)
Issuance of long-term debt									608.9	504.9	80.8
Net cash provided by (used in) financing activities									1,621.1	1,733.7	1,052.7
Net increase (decrease) in cash and cash equivalents									333.9	(461.6)	506.7
Cash and cash equivalents at beginning of period				2,515.9				2,977.5	2,515.9	2,977.5	2,470.8
Cash and cash equivalents at end of period	2,849.8				2,515.9				2,849.8	2,515.9	2,977.5
Principal Financial Group, Inc. parent only | Legal Entities
Operating activities
Net income (loss)									1,395.8	1,394.2	1,546.5
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Net realized capital (gains) losses									(7)	(12.3)	8.2
Stock-based compensation									1.4	1.3	2.9
Equity in the net (income) loss of subsidiaries									(1,529.4)	(1,529.2)	(1,658.3)
Changes in:
Net cash flows for trading securities and equity securities with operating intent									88.4	48.7	32.4
Current and deferred income taxes (benefits)									(13.5)	(31)	15.7
Other									49.1	135.4	(79.8)
Net cash provided by (used in) operating activities									(15.2)	7.1	(132.4)
Investing activities
Fixed maturities available-for-sale and equity securities with intent to hold: Purchases									(736.5)	(251.5)	(210.9)
Fixed maturities available-for-sale and equity securities with intent to hold: Maturities									193.7	200	2.3
Net (purchases) sales of property and equipment									(0.1)	(0.1)	(0.1)
Net change in other investments									(50)	(34)	(2.2)
Dividends and returns of capital received from unconsolidated entities									799.1	494.2	1,041.6
Net cash provided by (used in) investing activities									206.2	408.6	830.7
Financing activities
Issuance of common stock									42.8	37.7	64
Acquisition of treasury stock									(307)	(281)	(671.6)
Dividends to common stockholders									(614.5)	(606)	(598.6)
Issuance of long-term debt									595.2	493.6
Net cash provided by (used in) financing activities									(283.5)	(355.7)	(1,206.2)
Net increase (decrease) in cash and cash equivalents									(92.5)	60	(507.9)
Cash and cash equivalents at beginning of period				$ 394.9				$ 334.9	394.9	334.9	842.8
Cash and cash equivalents at end of period	$ 302.4				$ 394.9				$ 302.4	$ 394.9	$ 334.9

Schedule II - Condensed Finan_6

Schedule II - Condensed Financial Information of Registrant (Parent Only) - Financial Statement Footnotes (Details) - Principal Financial Group, Inc. parent only - Legal Entities - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividends and Returns of Capital Received from (Contributed to) Unconsolidated Entities
Dividends and returns of capital received from unconsolidated entities	$ 799.1	$ 494.2	$ 1,041.6
Nonqualified benefit plans
Condensed Financial Statements, Captions [Line Items]
Assets held in Rabbi trusts	801.7	731.9
Liabilities held in Rabbi trusts	$ 653.3	$ 593.7

Schedule III - Supplementary _2

Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplementary Insurance Information
Deferred acquisition costs	$ 3,409.7	$ 3,521.3	$ 3,693.5	$ 3,540.7
Future policy benefits and claims	45,207.2	40,838.2
Contractholder and other policyholder funds	44,297.1	42,326.9
Premiums and other considerations	6,037.4	7,866.6	6,409.6
Net investment income (loss)	3,890.6	3,998.4	3,629.2
Benefits, claims and settlement expenses	8,281.5	9,905.8	8,192.5
Amortization of deferred acquisition costs	388.1	347	253.5
Other operating expenses	4,258.4	4,156.9	3,883.2
Retirement and Income Solutions
Supplementary Insurance Information
Deferred acquisition costs	730.4	833.9
Future policy benefits and claims	28,134.1	25,305.1
Contractholder and other policyholder funds	35,576	33,814.4
Premiums and other considerations	3,221	4,862.7	3,635.9
Net investment income (loss)	2,457.9	2,420.4	2,195.2
Benefits, claims and settlement expenses	4,899.4	6,527.8	5,099
Amortization of deferred acquisition costs	82.2	87.8	124.5
Other operating expenses	1,578.2	1,403.5	1,140.7
Principal Global Investors
Supplementary Insurance Information
Net investment income (loss)	5.6	10.1	4.2
Other operating expenses	1,029.6	1,028.5	1,168
Principal International
Supplementary Insurance Information
Deferred acquisition costs	11.2	11.3
Future policy benefits and claims	5,109.5	4,537.1
Contractholder and other policyholder funds	1,167.3	1,145
Premiums and other considerations	156.6	393.3	317.2
Net investment income (loss)	446.8	575.9	494.9
Benefits, claims and settlement expenses	440.7	728.3	646.6
Amortization of deferred acquisition costs	1.2	1.3	1.3
Other operating expenses	416.8	436	451
U.S. Insurance Solutions
Supplementary Insurance Information
Deferred acquisition costs	2,668.1	2,676.1
Future policy benefits and claims	11,800.3	10,823.5
Contractholder and other policyholder funds	7,909.5	7,720
Premiums and other considerations	2,659.8	2,610.6	2,456.5
Net investment income (loss)	850.6	854.5	815.1
Benefits, claims and settlement expenses	2,937.2	2,639.2	2,444.6
Amortization of deferred acquisition costs	304.7	257.9	127.7
Other operating expenses	936.9	946.5	925.4
Corporate
Supplementary Insurance Information
Future policy benefits and claims	163.3	172.5
Contractholder and other policyholder funds	(355.7)	(352.5)
Net investment income (loss)	129.7	137.5	119.8
Benefits, claims and settlement expenses	4.2	10.5	2.3
Other operating expenses	$ 296.9	$ 342.4	$ 198.1

Schedule IV - Reinsurance (Deta

Schedule IV - Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Life insurance in force
Life insurance in force gross amount	$ 626,155.6	$ 577,735.3	$ 530,828.6
Life insurance in force ceded to other companies	377,308.2	368,583	324,691.3
Life insurance in force assumed from other companies	904.1	999.5	1,028.6
Life insurance in force net amount	$ 249,751.5	$ 210,151.8	$ 207,165.9
Life insurance in force, percentage of amount assumed to net (as a percent)	0.40%	0.50%	0.50%
Premiums:
Premiums gross amount	$ 6,645.4	$ 8,428.1	$ 6,928.3
Premiums ceded to other companies	609.7	563.1	520.4
Premiums assumed from other companies	1.7	1.6	1.7
Premiums net amount	6,037.4	7,866.6	6,409.6
Life insurance and annuities
Premiums:
Premiums gross amount	4,608.7	6,424.8	5,055.8
Premiums ceded to other companies	453.1	407.5	359.9
Premiums assumed from other companies	1.7	1.6	1.7
Premiums net amount	4,157.3	6,018.9	4,697.6
Accident and health insurance
Premiums:
Premiums gross amount	2,036.7	2,003.3	1,872.5
Premiums ceded to other companies	156.6	155.6	160.5
Premiums net amount	$ 1,880.1	$ 1,847.7	$ 1,712