Principal Financial (PFG) 10-K 12 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 05, 2014	Jun. 28, 2013
Document and Entity Information	'	'	'
Entity Registrant Name	'PRINCIPAL FINANCIAL GROUP INC	'	'
Entity Central Index Key	'0001126328	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Amendment Flag	'false	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$11,007,711,269
Entity Common Stock, Shares Outstanding	'	295,521,829	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'

Consolidated_Statements_of_Fin

Consolidated Statements of Financial Position (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Assets	'	'	'	'
Fixed maturities, available-for-sale (2013 and 2012 include $272.0 million and $194.6 million related to consolidated variable interest entities)	$48,757.10	$50,939.30	'	'
Fixed maturities, trading (2013 and 2012 both include $110.4 million related to consolidated variable interest entities)	563.1	626.7	'	'
Equity securities, available-for-sale	110.5	136.5	'	'
Equity securities, trading (2013 includes $327.2 million related to consolidated variable interest entities)	716.9	252.8	'	'
Mortgage loans	11,533.60	11,519.70	'	'
Real estate	1,271.60	1,180.30	'	'
Policy loans	859.7	864.9	'	'
Other investments (2013 and 2012 include $68.1 million and $80.3 million related to consolidated variable interest entities and $142.9 million and $113.9 million measured at fair value under the fair value option)	2,944.40	3,291.10	'	'
Total investments	66,756.90	68,811.30	'	'
Cash and cash equivalents	2,371.80	4,177.20	2,833.90	1,877.40
Accrued investment income	532.1	584.4	'	'
Premiums due and other receivables	1,241	1,084.40	'	'
Deferred acquisition costs	3,077	2,590	2,358.10	2,442.20
Property and equipment	500.7	464.2	'	'
Goodwill	1,100.30	543.4	482.3	'
Other intangibles	1,459	914.7	'	'
Separate account assets (2013 includes $32,824.7 million related to consolidated variable interest entities)	130,018.40	81,653.80	'	'
Other assets	1,134.20	1,006.80	'	'
Total assets	208,191.40	161,830.20	'	'
Liabilities	'	'	'	'
Contractholder funds	35,958.30	37,786.50	'	'
Future policy benefits and claims	22,626.20	22,436.20	'	'
Other policyholder funds	758.9	716.4	'	'
Short-term debt	150.6	40.8	'	'
Long-term debt	2,601.40	2,671.30	'	'
Income taxes currently payable	5.2	15.3	'	'
Deferred income taxes	824	600	'	'
Separate account liabilities (2013 includes $32,824.7 million related to consolidated variable interest entities)	130,018.40	81,653.80	'	'
Other liabilities (2013 and 2012 include $342.4 million and $302.9 million related to consolidated variable interest entities, of which $104.9 million and $85.0 million are measured at fair value under the fair value option)	5,224.20	6,146.10	'	'
Total liabilities	198,167.20	152,066.40	'	'
Redeemable noncontrolling interest	247.2	60.4	22.2	'
Stockholders' equity	'	'	'	'
Common stock, par value $.01 per share - 2,500.0 million shares authorized, 459.3 million and 453.5 million shares issued, and 295.2 million and 293.8 million shares outstanding in 2013 and 2012	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income (loss)	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Noncontrolling interest	92.8	20	'	'
Total stockholders' equity	9,777	9,703.40	9,306.20	9,246.80
Total liabilities and stockholders' equity	208,191.40	161,830.20	'	'
Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
Total stockholders' equity	0	0	0	0
Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	0.1	0.1	0.1	'
Total stockholders' equity	$0.10	$0.10	$0.10	$0.10

Consolidated_Statements_of_Fin1

Consolidated Statements of Financial Position (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, except Per Share data, unless otherwise specified
Fixed maturities, available-for-sale	$48,757.10	$50,939.30
Fixed maturities, trading	563.1	626.7
Equity securities, trading	716.9	252.8
Other investments	2,944.40	3,291.10
Other investments measured at fair value under fair value option	142.9	113.9
Separate account assets	130,018.40	81,653.80
Separate account liabilities	130,018.40	81,653.80
Other liabilities	5,224.20	6,146.10
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)	459.3	453.5
Common stock, outstanding (in shares)	295.2	293.8
Treasury stock (in shares)	164.1	159.7
Series A	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, liquidation preference (in dollars per share)	$100	$100
Preferred stock, authorized (in shares)	3	3
Preferred stock, issued (in shares)	3	3
Preferred stock, outstanding (in shares)	3	3
Series B	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, liquidation preference (in dollars per share)	$25	$25
Preferred stock, authorized (in shares)	10	10
Preferred stock, issued (in shares)	10	10
Preferred stock, outstanding (in shares)	10	10
Aggregate consolidated variable interest entities	'	'
Fixed maturities, available-for-sale	272	194.6
Fixed maturities, trading	110.4	110.4
Equity securities, trading	327.2	'
Other investments	68.1	80.3
Separate account assets	32,824.70	'
Separate account liabilities	32,824.70	'
Other liabilities	342.4	302.9
Other liabilities measured at fair value under fair value option	$104.90	$85

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	$700.10	$1,158.20	$681.30	$679.80	$3,154.10	$3,219.40	$2,891
Fees and other revenues	'	'	'	'	717.6	675	636.1	598	3,222.20	2,626.70	2,526.70
Net investment income (loss)	'	'	'	'	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	56.3	122.1	32.2	22.1	-109.2	232.7	75
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	-9.5	-43.6	-49.1	-33.7	-91.5	-135.9	-147.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	-13.9	9.2	17.1	4.9	-24.5	17.3	-49.7
Net impairment losses on available-for-sale securities	'	'	'	'	-23.4	-34.4	-32	-28.8	-116	-118.6	-197.3
Net realized capital gains (losses)	'	'	'	'	32.9	87.7	0.2	-6.7	-225.2	114.1	-122.3
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	1,154.40	1,647	1,110	1,212.50	4,683.60	5,123.90	4,616.60
Dividends to policyholders	'	'	'	'	48.2	49.7	49.5	50.3	189	197.7	210.2
Operating expenses	'	'	'	'	832.4	816.4	729.6	555.1	3,292.90	2,933.50	2,971.10
Total expenses	2,362.70	1,919.30	1,945	1,938.50	2,035	2,513.10	1,889.10	1,817.90	8,165.50	8,255.10	7,797.90
Income (loss) before income taxes	'	'	'	'	260.9	191.6	229.5	278	1,124	960	872.8
Income taxes (benefits)	'	'	'	'	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Net income (loss) attributable to noncontrolling interest	'	'	'	'	3.5	3.4	2.7	9.2	23.4	18.8	36.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	223.2	195.4	175.9	212.1	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	33	33	33
Net income (loss) available to common stockholders	$233.40	$245.70	$222.30	$178.30	$214.90	$187.20	$167.60	$203.90	$879.70	$773.60	$605.30
Earnings per common share	'	'	'	'	'	'	'	'	'	'	'
Basic earnings per common share (in dollars per share)	$0.79	$0.83	$0.76	$0.61	$0.72	$0.64	$0.56	$0.68	$2.99	$2.60	$1.92
Diluted earnings per common share (in dollars per share)	$0.78	$0.82	$0.75	$0.61	$0.72	$0.63	$0.56	$0.68	$2.95	$2.58	$1.91

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statements of Comprehensive Income	'	'	'	'	'	'	'	'	'	'	'
Net income (loss)	$250.40	$259.10	$236.60	$190	$226.70	$198.80	$178.60	$221.30	$936.10	$825.40	$674.50
Other comprehensive income (loss), net:	'	'	'	'	'	'	'	'	'	'	'
Net unrealized gains (losses) on available-for-sale securities	'	'	'	'	'	'	'	'	-540.2	557.6	208.6
Noncredit component of impairment losses on fixed maturities, available-for-sale	'	'	'	'	'	'	'	'	6.9	-6.7	31
Net unrealized gains (losses) on derivative instruments	'	'	'	'	'	'	'	'	-1.8	-43.6	23.6
Foreign currency translation adjustment	'	'	'	'	'	'	'	'	-269.4	-9.8	-130.9
Net unrecognized postretirement benefit obligation	'	'	'	'	'	'	'	'	332.6	-127.4	-172.9
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-471.9	370.1	-40.6
Comprehensive income (loss)	'	'	'	'	'	'	'	'	464.2	1,195.50	633.9
Comprehensive income (loss) attributable to noncontrolling interest	'	'	'	'	'	'	'	'	8.6	20	35.7
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	$455.60	$1,175.50	$598.20

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common stock	Additional paid-in capital	Retained earnings (accumulated deficit)	Accumulated other comprehensive income (loss)	Treasury stock	Noncontrolling interest	Series A	Series B
In Millions, unless otherwise specified
Balances at Dec. 31, 2010	$9,246.80	$4.50	$9,564	$3,934.80	$311.50	($4,725.30)	$157.20	$0	$0.10
Increase (decrease) in stockholders' equity	'	'	'	'	'	'	'	'	'
Common stock issued	25.9	'	25.9	'	'	'	'	'	'
Stock-based compensation and additional related tax benefits	43.8	'	46.8	-3	'	'	'	'	'
Treasury stock acquired, common	-556.4	'	'	'	'	-556.4	'	'	'
Dividends to common stockholders	-213.7	'	'	-213.7	'	'	'	'	'
Dividends to preferred stockholders	-33	'	'	-33	'	'	'	'	'
Distributions to noncontrolling interest	-9.8	'	'	'	'	'	-9.8	'	'
Contributions from noncontrolling interest	174.6	'	'	'	'	'	174.6	'	'
Purchase of subsidiary shares from noncontrolling interest	-5.7	'	-2	'	'	'	-3.7	'	'
Net income (loss) (excludes $13.6 million, $1.9 million and $0.2 million attributable to redeemable noncontrolling interest in 2013, 2012 and 2011, respectively)	674.3	'	'	638.3	'	'	36	'	'
Other comprehensive income (loss) (excludes $(4.8) million, $1.1 million attributable to redeemable noncontrolling interest in 2013 and 2012, respectively)	-40.6	'	'	'	-40.1	'	-0.5	'	'
Balances at Dec. 31, 2011	9,306.20	4.5	9,634.70	4,323.40	271.4	-5,281.70	353.8	0	0.1
Increase (decrease) in stockholders' equity	'	'	'	'	'	'	'	'	'
Common stock issued	28.9	'	28.9	'	'	'	'	'	'
Stock-based compensation and additional related tax benefits	63.6	'	67.3	-3.7	'	'	'	'	'
Treasury stock acquired, common	-272.7	'	'	'	'	-272.7	'	'	'
Dividends to common stockholders	-231.3	'	'	-231.3	'	'	'	'	'
Dividends to preferred stockholders	-33	'	'	-33	'	'	'	'	'
Distributions to noncontrolling interest	-10.7	'	'	'	'	'	-10.7	'	'
Contributions from noncontrolling interest	13.1	'	'	'	'	'	13.1	'	'
Deconsolidation of certain variable interest entities	-353.2	'	'	'	'	'	-353.2	'	'
Net income (loss) (excludes $13.6 million, $1.9 million and $0.2 million attributable to redeemable noncontrolling interest in 2013, 2012 and 2011, respectively)	823.5	'	'	806.6	'	'	16.9	'	'
Other comprehensive income (loss) (excludes $(4.8) million, $1.1 million attributable to redeemable noncontrolling interest in 2013 and 2012, respectively)	369	'	'	'	368.9	'	0.1	'	'
Balances at Dec. 31, 2012	9,703.40	4.5	9,730.90	4,862	640.3	-5,554.40	20	0	0.1
Increase (decrease) in stockholders' equity	'	'	'	'	'	'	'	'	'
Common stock issued	125.8	0.1	125.7	'	'	'	'	'	'
Stock-based compensation and additional related tax benefits	68.1	'	72.7	-4.6	'	'	'	'	'
Treasury stock acquired, common	-153.6	'	'	'	'	-153.6	'	'	'
Dividends to common stockholders	-288.4	'	'	-288.4	'	'	'	'	'
Dividends to preferred stockholders	-33	'	'	-33	'	'	'	'	'
Distributions to noncontrolling interest	-2	'	'	'	'	'	-2	'	'
Contributions from noncontrolling interest	115.3	'	'	'	'	'	115.3	'	'
Purchase of subsidiary shares from noncontrolling interest	-52.7	'	1.4	'	'	'	-54.1	'	'
Sale of subsidiary shares to noncontrolling interest	31.8	'	11.5	'	'	'	20.3	'	'
Adjustments to redemption amount of redeemable noncontrolling interest	-193.1	'	-143.3	-43.3	'	'	-6.5	'	'
Net income (loss) (excludes $13.6 million, $1.9 million and $0.2 million attributable to redeemable noncontrolling interest in 2013, 2012 and 2011, respectively)	922.5	'	'	912.7	'	'	9.8	'	'
Other comprehensive income (loss) (excludes $(4.8) million, $1.1 million attributable to redeemable noncontrolling interest in 2013 and 2012, respectively)	-467.1	'	'	'	-457.1	'	-10	'	'
Balances at Dec. 31, 2013	$9,777	$4.60	$9,798.90	$5,405.40	$183.20	($5,708)	$92.80	$0	$0.10

Consolidated_Statements_of_Sto1

Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Consolidated Statements of Stockholders' Equity	'	'
Net income (loss) attributable to redeemable noncontrolling interest	$13.60	$1.90
Other comprehensive income (loss) attributable to redeemable noncontrolling interest	($4.80)	$1.10

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities	'	'	'
Net income (loss)	$936.10	$825.40	$674.50
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:	'	'	'
Amortization of deferred acquisition costs	187.1	94.9	271.4
Additions to deferred acquisition costs	-447	-428.9	-344.4
Accrued investment income	52.3	30.8	50.9
Net cash flows for trading securities	-76	335.8	110.8
Premiums due and other receivables	-131.9	70.6	-130.2
Contractholder and policyholder liabilities and dividends	1,614.70	2,054.70	1,017.70
Current and deferred income taxes (benefits)	211.7	18.4	17.8
Net realized capital (gains) losses	225.2	-114.1	122.3
Depreciation and amortization expense	153.9	132.1	119.9
Mortgage loans held for sale, acquired or originated	'	-48	-132.3
Mortgage loans held for sale, sold or repaid, net of gain	0.2	90	82
Real estate acquired through operating activities	-107.2	-46.4	-37.4
Real estate sold through operating activities	24.2	43.9	141.8
Stock-based compensation	68.5	63.8	43.4
Other	-490.6	-42.2	705.1
Net adjustments	1,285.10	2,255.40	2,038.80
Net cash provided by (used in) operating activities	2,221.20	3,080.80	2,713.30
Investing activities	'	'	'
Available-for-sale securities: Purchases	-9,025.20	-8,263.90	-6,742.40
Available-for-sale securities: Sales	1,919.10	1,303.70	980.7
Available-for-sale securities: Maturities	7,359.20	6,647.50	5,760.80
Mortgage loans acquired or originated	-2,192.90	-2,538.40	-1,484.90
Mortgage loans sold or repaid	2,095.10	1,668	1,793.10
Real estate acquired	-85.6	-151.8	-129.9
Net (purchases) sales of property and equipment	-59.4	-38.9	-56.9
Purchases of interest in subsidiaries, net of cash acquired	-1,268.30	-80.4	-270.5
Net change in other investments	31.7	-157.1	-52.1
Net cash provided by (used in) investing activities	-1,226.30	-1,611.30	-202.1
Financing activities	'	'	'
Issuance of common stock	125.8	28.9	25.9
Acquisition of treasury stock	-153.6	-272.7	-556.4
Proceeds from financing element derivatives	47	51.8	75.9
Payments for financing element derivatives	-48	-49.9	-46.5
Excess tax benefits from share-based payment arrangements	10.1	10.8	2
Purchase of subsidiary shares from noncontrolling interest	-52.9	'	'
Sale of subsidiary shares to noncontrolling interest	31.8	'	'
Dividends to common stockholders	-288.4	-231.3	-213.7
Dividends to preferred stockholders	-33	-33	-33
Issuance of long-term debt	38.2	1,493.40	'
Principal repayments of long-term debt	-218.2	-450.6	-12.2
Net proceeds from (repayments of) short-term borrowings	108	-68.8	3.2
Investment contract deposits	6,716.30	6,900.40	6,302.10
Investment contract withdrawals	-8,852.70	-7,522.60	-7,079
Net increase (decrease) in banking operation deposits	-225.7	32	-18.5
Other	-5	-14.6	-4.5
Net cash provided by (used in) financing activities	-2,800.30	-126.2	-1,554.70
Net increase (decrease) in cash and cash equivalents	-1,805.40	1,343.30	956.5
Cash and cash equivalents at beginning of period	4,177.20	2,833.90	1,877.40
Cash and cash equivalents at end of period	2,371.80	4,177.20	2,833.90
Supplemental Information:	'	'	'
Cash paid for interest	144.1	127.7	154.1
Cash paid for income taxes	$61.20	$82.70	$152.80

Nature_of_Operations_and_Signi

Nature of Operations and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
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"), along with its consolidated subsidiaries, is a diversified financial services organization offering retirement services, insurance solutions and asset management in the U.S. and selected international markets.
	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. Entities in which we have significant 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. 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.
	Reclassifications have been made to prior period financial statements to conform to the December 31, 2013, presentation.
	Revisions of Previously Issued Financial Statements
	In conjunction with our first quarter 2013 acquisition of AFP Cuprum S.A. ("Cuprum") in Chile, we re-evaluated the accounting treatment for similar products offered in other foreign jurisdictions, including the AFORE retirement accumulation business in Mexico. As a result of this re-evaluation, we have concluded that the AFORE product, which was previously accounted for under Accounting Standards Codification 944, Financial Services — Insurance, should be accounted for as a long-term service contract, consistent with the accounting requirements for our recently acquired retirement accumulation business in Chile. The revision to the accounting treatment for the AFORE product in Mexico resulted in the following changes:
	(a)
	Fewer acquisition costs are capitalized. Specifically, we expense as incurred salary and related costs associated with the successful efforts of our proprietary sales force and sales support staff. All direct and incremental costs such as commissions will continue to be deferred.
	(b)
	Deferred costs are amortized on a straight line basis over the expected contract life rather than based on estimated gross profits. The amortization method change also impacts purchased customer intangible assets.
	We have revised our prior period consolidated financial statements accordingly. These revisions, inclusive of any other potential adjustments, are not material in any prior period based on an analysis of quantitative and qualitative factors in accordance with SEC Staff Accounting Bulletins 99 and 108, and, as a result, amendment of previously filed periodic reports is not required.
	The following tables quantify the prior period impact of this revision.
	Principal Financial Group, Inc.
	Consolidated Statements of Financial Position
		December 31, 2012
		As originally			As adjusted
		reported
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	50,939.30		$	50,939.30
	Fixed maturities, trading		626.7			626.7
	Equity securities, available-for-sale		136.5			136.5
	Equity securities, trading		252.8			252.8
	Mortgage loans		11,519.70			11,519.70
	Real estate		1,180.30			1,180.30
	Policy loans		864.9			864.9
	Other investments		3,291.10			3,291.10
	Total investments		68,811.30			68,811.30
	Cash and cash equivalents		4,177.20			4,177.20
	Accrued investment income		584.4			584.4
	Premiums due and other receivables		1,084.40			1,084.40
	Deferred acquisition costs		2,673.80			2,590.00
	Property and equipment		464.2			464.2
	Goodwill		543.4			543.4
	Other intangibles		927.2			914.7
	Separate account assets		81,653.80			81,653.80
	Other assets		1,006.80			1,006.80
	Total assets	$	161,926.50		$	161,830.20
	Liabilities
	Contractholder funds	$	37,786.50		$	37,786.50
	Future policy benefits and claims		22,436.20			22,436.20
	Other policyholder funds		716.4			716.4
	Short-term debt		40.8			40.8
	Long-term debt		2,671.30			2,671.30
	Income taxes currently payable		15.3			15.3
	Deferred income taxes		626.5			600
	Separate account liabilities		81,653.80			81,653.80
	Other liabilities		6,146.10			6,146.10
	Total liabilities		152,092.90			152,066.40
	Redeemable noncontrolling interest		60.4			60.4
	Stockholders' equity
	Series A preferred stock, par value		—			—
	Series B preferred stock, par value		0.1			0.1
	Common stock, par value		4.5			4.5
	Additional paid-in capital		9,730.90			9,730.90
	Retained earnings		4,940.20			4,862.00
	Accumulated other comprehensive income		631.9			640.3
	Treasury stock, at cost		(5,554.4	)		(5,554.4	)
	Total stockholders' equity attributable to Principal Financial Group, Inc.		9,753.20			9,683.40
	Noncontrolling interest		20			20
	Total stockholders' equity		9,773.20			9,703.40
Total liabilities and stockholders' equity	$	161,926.50		$	161,830.20
Principal Financial Group, Inc.
Consolidated Statements of Operations
	For the year ended						For the year ended
	December 31, 2012						December 31, 2011
	As originally			As adjusted			As originally			As adjusted
	reported						reported
	(in millions, except per share data)
Revenues
Premiums and other considerations	$	3,219.40		$	3,219.40		$	2,891.00		$	2,891.00
Fees and other revenues		2,626.70			2,626.70			2,526.70			2,526.70
Net investment income		3,254.90			3,254.90			3,375.30			3,375.30
Net realized capital gains, excluding impairment losses on available-for-sale securities		232.7			232.7			75			75
Total other-than-temporary impairment losses on available-for- sale securities		(135.9	)		(135.9	)		(147.6	)		(147.6	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income		17.3			17.3			(49.7	)		(49.7	)
Net impairment losses on available-for-sale securities		(118.6	)		(118.6	)		(197.3	)		(197.3	)
Net realized capital gains (losses)		114.1			114.1			(122.3	)		(122.3	)
Total revenues		9,215.10			9,215.10			8,670.70			8,670.70
Expenses
Benefits, claims and settlement expenses		5,123.90			5,123.90			4,616.60			4,616.60
Dividends to policyholders		197.7			197.7			210.2			210.2
Operating expenses		2,934.10			2,933.50			2,950.80			2,971.10
Total expenses		8,255.70			8,255.10			7,777.60			7,797.90
Income before income taxes		959.4			960			893.1			872.8
Income taxes		134.7			134.6			204.2			198.3
Net income		824.7			825.4			688.9			674.5
Net income attributable to noncontrolling interest		18.8			18.8			36.2			36.2
Net income attributable to Principal Financial Group, Inc.		805.9			806.6			652.7			638.3
Preferred stock dividends		33			33			33			33
Net income available to common stockholders	$	772.9		$	773.6		$	619.7		$	605.3
Earnings per common share
Basic earnings per common share	$	2.6		$	2.6		$	1.97		$	1.92
Diluted earnings per common share	$	2.57		$	2.58		$	1.95		$	1.91
Principal Financial Group, Inc.
Consolidated Statements of Operations
	For the three months						For the three months						For the three months						For the three months
	ended						ended						ended						ended
	March 31, 2012						June 30, 2012						September 30, 2012						December 31, 2012
	As originally			As adjusted			As originally			As adjusted			As originally			As adjusted			As originally			As adjusted
	reported						reported						reported						reported
	(in millions, except per share data)
Revenues
Premiums and other considerations	$	679.8		$	679.8		$	681.3		$	681.3		$	1,158.20		$	1,158.20		$	700.1		$	700.1
Fees and other revenues		598			598			636.1			636.1			675			675			717.6			717.6
Net investment income		824.8			824.8			801			801			783.8			783.8			845.3			845.3
Net realized capital gains, excluding impairment losses on available-for-sale securities		22.1			22.1			32.2			32.2			122.1			122.1			56.3			56.3
Total other-than-temporary impairment losses on available-for-sale securities		(33.7	)		(33.7	)		(49.1	)		(49.1	)		(43.6	)		(43.6	)		(9.5	)		(9.5	)
Other-than-temporary impairment losses on fixed maturities, available-for- sale reclassified to (from) other comprehensive income		4.9			4.9			17.1			17.1			9.2			9.2			(13.9	)		(13.9	)
Net impairment losses on available-for-sale securities		(28.8	)		(28.8	)		(32.0	)		(32.0	)		(34.4	)		(34.4	)		(23.4	)		(23.4	)
Net realized capital gains (losses)		(6.7	)		(6.7	)		0.2			0.2			87.7			87.7			32.9			32.9
Total revenues		2,095.90			2,095.90			2,118.60			2,118.60			2,704.70			2,704.70			2,295.90			2,295.90
Expenses
Benefits, claims and settlement expenses		1,212.50			1,212.50			1,110.00			1,110.00			1,647.00			1,647.00			1,154.40			1,154.40
Dividends to policyholders		50.3			50.3			49.5			49.5			49.7			49.7			48.2			48.2
Operating expenses		556			555.1			724.1			729.6			826.6			816.4			827.4			832.4
Total expenses		1,818.80			1,817.90			1,883.60			1,889.10			2,523.30			2,513.10			2,030.00			2,035.00
Income before income taxes		277.1			278			235			229.5			181.4			191.6			265.9			260.9
Income taxes (benefits)		58.2			56.7			50.9			50.9			(9.9	)		(7.2	)		35.5			34.2
Net income		218.9			221.3			184.1			178.6			191.3			198.8			230.4			226.7
Net income attributable to noncontrolling interest		9.2			9.2			2.7			2.7			3.4			3.4			3.5			3.5
Net income attributable to Principal Financial Group, Inc.		209.7			212.1			181.4			175.9			187.9			195.4			226.9			223.2
Preferred stock dividends		8.2			8.2			8.3			8.3			8.2			8.2			8.3			8.3
Net income available to common stockholders	$	201.5		$	203.9		$	173.1		$	167.6		$	179.7		$	187.2		$	218.6		$	214.9
Earnings per common share
Basic earnings per common share	$	0.67		$	0.68		$	0.58		$	0.56		$	0.61		$	0.64		$	0.74		$	0.72
Diluted earnings per common share	$	0.66		$	0.68		$	0.58		$	0.56		$	0.6		$	0.63		$	0.74		$	0.72
Principal Financial Group, Inc.
Consolidated Statements of Comprehensive Income
	For the year ended						For the year ended
	December 31, 2012						December 31, 2011
	As originally			As adjusted			As originally			As adjusted
	reported						reported
	(in millions)
Net income	$	824.7		$	825.4		$	688.9		$	674.5
Other comprehensive income (loss), net:
Net unrealized gains on available-for-sale securities		557.6			557.6			208.6			208.6
Noncredit component of impairment losses on fixed maturities, available-for-sale		(6.7	)		(6.7	)		31			31
Net unrealized gains (losses) on derivative instruments		(43.6	)		(43.6	)		23.6			23.6
Foreign currency translation adjustment		(4.8	)		(9.8	)		(139.5	)		(130.9	)
Net unrecognized postretirement benefit obligation		(127.4	)		(127.4	)		(172.9	)		(172.9	)
Other comprehensive income (loss)		375.1			370.1			(49.2	)		(40.6	)
Comprehensive income		1,199.80			1,195.50			639.7			633.9
Comprehensive income attributable to noncontrolling interest		20			20			35.7			35.7
Comprehensive income attributable to Principal Financial Group, Inc.	$	1,179.80		$	1,175.50		$	604		$	598.2
Certain of the prior period line items in the consolidated statements of cash flows and stockholders' equity were immaterially affected by the revisions of previously issued financial statements. All of the line item changes in the consolidated statements of cash flows were included in the operating activities section and the changes in the consolidated statements of stockholders' equity have largely been addressed through the preceding disclosures.
Recent Accounting Pronouncements
In January 2014, the Financial Accounting Standards Board ("FASB") issued authoritative guidance to reduce diversity in practice by clarifying when an in substance repossession or foreclosure occurs. This guidance will be effective for us beginning January 1, 2015, and is not expected to have a material impact on our consolidated financial statements.
Also, in January 2014, the FASB issued authoritative guidance on accounting for investments by a reporting entity in flow-through limited liability entities that manage or invest in affordable housing projects that qualify for the low-income housing tax credit. This guidance will be effective for us beginning January 1, 2015, and is not expected to have a material impact on our consolidated financial statements.
In July 2013, the FASB issued authoritative guidance that requires the liability related to certain unrecognized benefits to be offset against a deferred tax asset from operating loss carryforwards. This guidance will be effective for us beginning January 1, 2014, and is not expected to have a material impact on our consolidated financial statements.
In June 2013, the FASB issued authoritative guidance that formalizes the definition of an investment company. This guidance will be effective for us beginning January 1, 2014, and is not expected to have a material impact on our consolidated financial statements.
In March 2013, the FASB issued authoritative guidance that clarifies how the cumulative translation adjustment ("CTA") related to a parent's investment in a foreign entity should be released when certain transactions related to the foreign entity occur. This guidance will be effective prospectively for us beginning January 1, 2014, and is not expected to have a material impact on our consolidated financial statements.
In February 2013, the FASB issued authoritative guidance that requires entities to disclose additional information about items reclassified out of accumulated other comprehensive income ("AOCI"). Entities are required to disclose information regarding changes in AOCI balances by component and significant items reclassified out of AOCI by component either on the face of the income statement or as a separate footnote to the financial statements. This guidance was effective for us beginning January 1, 2013, and did not have a material impact on our consolidated financial statements. This guidance did not impact the requirements for reporting of comprehensive income under FASB guidance issued in June 2011, which changed the presentation of comprehensive income in the financial statements. The guidance eliminated the presentation options contained in previous guidance and instead required entities to report components of comprehensive income in either a continuous statement of comprehensive income or two separate but consecutive statements that show the components of net income and other comprehensive income ("OCI"), including adjustments for items that are reclassified from OCI to net income. The guidance did not change the items that must be reported in OCI or when an item of OCI must be reclassified to net income. This guidance was effective for us on January 1, 2012, and did not have a material impact on our consolidated financial statements. See Note 14, Stockholders' Equity, for further details.
In January 2013 and December 2011, the FASB issued authoritative guidance related to balance sheet offsetting. The 2011 guidance requires disclosures about assets and liabilities that are offset or have the potential to be offset. These disclosures are intended to address differences in the asset and liability offsetting requirements under U.S. GAAP and International Financial Reporting Standards. The 2013 guidance clarified that the disclosure requirements would apply to derivative instruments, including bifurcated embedded derivatives, repurchase and reverse repurchase agreements and securities borrowing and securities lending arrangements that are either offset on the balance sheet or subject to an enforceable master netting arrangement or similar agreement. Both pieces of guidance were effective for us beginning January 1, 2013, with retrospective application required and did not have a material impact on our consolidated financial statements. See Note 5, Investments, for further details.
In July 2012, the FASB issued authoritative guidance that amends how indefinite-lived intangible assets are tested for impairment. The amendments provide an option to perform a qualitative assessment to determine whether it is necessary to perform the annual fair value calculation impairment test. This new guidance was effective for our 2013 indefinite-lived intangible asset impairment testing and did not have a material impact on our consolidated financial statements.
In December 2011, the FASB issued authoritative guidance that requires a reporting entity to follow the real estate sales guidance when the reporting entity ceases to have a controlling financial interest in a subsidiary that is in-substance real estate as a result of a default on the subsidiary's nonrecourse debt. This guidance was effective for us on January 1, 2013, and did not have a material impact on our consolidated financial statements.
In September 2011, the FASB issued authoritative guidance that amends how goodwill is tested for impairment. The amendments provide an option to perform a qualitative assessment to determine whether it is necessary to perform the annual two-step quantitative goodwill impairment test. This guidance was effective for our 2012 goodwill impairment test and did not have a material impact on our consolidated financial statements.
In June 2011, the FASB issued authoritative guidance that changes the presentation of comprehensive income in the financial statements. The new guidance eliminates the presentation options contained in current guidance and instead requires entities to report components of comprehensive income in either a continuous statement of comprehensive income or two separate but consecutive statements that show the components of net income and OCI, including adjustments for items that are reclassified from OCI to net income. The guidance does not change the items that must be reported in OCI or when an item of OCI must be reclassified to net income. In December 2011, the FASB issued a final standard to defer the new requirement to present classification adjustments out of OCI to net income on the face of the financial statements. All other requirements contained in the original statement on comprehensive income are still effective. This guidance was effective for us on January 1, 2012, and did not have a material impact on our consolidated financial statements. The required disclosures are included in our consolidated financial statements. See Note 14, Stockholders' Equity, for further details.
In May 2011, the FASB issued authoritative guidance that clarifies and changes fair value measurement and disclosure requirements. This guidance expands existing disclosure requirements for fair value measurements and makes other amendments but does not require additional fair value measurements. This guidance was effective for us on January 1, 2012, and did not have a material impact on our consolidated financial statements. See Note 15, Fair Value Measurements, for further details.
In April 2011, the FASB issued authoritative guidance that modifies the criteria for determining when repurchase agreements would be accounted for as secured borrowings as opposed to sales. The guidance was effective for us on January 1, 2012, for new transfers and modifications to existing transactions and did not have a material impact on our consolidated financial statements.
Also in April 2011, the FASB issued authoritative guidance which clarifies when creditors should classify a loan modification as a troubled debt restructuring ("TDR"). A TDR occurs when a creditor grants a concession to a debtor experiencing financial difficulties. Loans denoted as a TDR are considered impaired and are specifically reserved for when calculating the allowance for credit losses. This guidance also ended the indefinite deferral issued in January 2011 surrounding new disclosures on loans classified as a TDR required as part of the credit quality disclosures guidance issued in July 2010. This guidance was effective for us on July 1, 2011, and was applied retrospectively to restructurings occurring on or after January 1, 2011. This guidance did not have a material impact on our consolidated financial statements. See Note 5, Investments, for further details.
In October 2010, the FASB issued authoritative guidance that modifies the definition of the types of costs incurred by insurance entities that can be capitalized in the successful acquisition of new or renewal insurance contracts. Capitalized costs should include incremental direct costs of contract acquisition, as well as certain costs related directly to acquisition activities such as underwriting, policy issuance and processing, medical and inspection and sales force contract selling. This guidance was effective for us on January 1, 2012, and we adopted the guidance retrospectively.
In July 2010, the FASB issued authoritative guidance that requires new and expanded disclosures related to the credit quality of financing receivables and the allowance for credit losses. Reporting entities are required to provide qualitative and quantitative disclosures on the allowance for credit losses, credit quality, impaired loans, modifications and nonaccrual and past due financing receivables. The disclosures are required to be presented on a disaggregated basis by portfolio segment and class of financing receivable. Disclosures required by the guidance that relate to the end of a reporting period were effective for us in our December 31, 2010, consolidated financial statements. Disclosures required by the guidance that relate to an activity that occurs during a reporting period were effective for us on January 1, 2011, and did not have a material impact on our consolidated financial statements. See Note 5, Investments, for further details.
In April 2010, the FASB issued authoritative guidance addressing how investments held through the separate accounts of an insurance entity affect the entity's consolidation analysis. This guidance clarifies that an insurance entity should not consider any separate account interests held for the benefit of policyholders in an investment to be the insurer's interests and should not combine those interests with its general account interest in the same investment when assessing the investment for consolidation. This guidance was effective for us on January 1, 2011, and did not have a material impact on our consolidated financial statements.
In January 2010, the FASB issued authoritative guidance that requires new disclosures related to fair value measurements and clarifies existing disclosure requirements about the level of disaggregation, inputs and valuation techniques. Specifically, reporting entities now must disclose separately the amounts of significant transfers in and out of Level 1 and Level 2 fair value measurements and describe the reasons for the transfers. In addition, in the reconciliation for Level 3 fair value measurements, a reporting entity should present separately information about purchases, sales, issuances and settlements. The guidance clarifies that a reporting entity needs to use judgment in determining the appropriate classes of assets and liabilities for disclosure of fair value measurement, considering the level of disaggregated information required by other applicable U.S. GAAP guidance and should also provide disclosures about the valuation techniques and inputs used to measure fair value for each class of assets and liabilities. This guidance was effective for us on January 1, 2010, except for the disclosures about purchases, sales, issuances and settlements in the reconciliation for Level 3 fair value measurements, which were effective for us on January 1, 2011. This guidance did not have a material impact on our consolidated financial statements. See Note 15, Fair Value Measurements, for further details.
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 deferred acquisition costs ("DAC") and other actuarial balances where the amortization is based on estimated gross profits;
•
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. Many of these policies, estimates and related judgments are common in the insurance and financial services industries; others are specific to our businesses and operations. 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 7, 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, redeemable preferred stock and certain nonredeemable preferred securities. Equity securities include mutual funds, common stock and nonredeemable preferred stock. We classify fixed maturities and equity securities as either available-for-sale or trading at the time of the purchase and, accordingly, carry them at fair value. See Note 15, Fair Value Measurements, for methodologies related to the determination of fair value. Unrealized gains and losses related to available-for-sale securities, excluding those in fair value hedging relationships, are reflected in stockholders' equity, net of adjustments related to DAC, reinsurance assets or liabilities, sales inducements, unearned revenue reserves, policyholder liabilities, derivatives in cash flow hedge relationships and applicable income taxes. Unrealized gains and losses related to hedged portions of available-for-sale securities in fair value hedging relationships and mark-to-market adjustments on certain trading securities are reflected in net realized capital gains (losses). We also have certain equity securities, trading that represent mandatory required investments and a minimal amount of assets within trading securities portfolios that support investment strategies that involve the active and frequent purchase and sale of fixed maturities. Mark-to-market adjustments related to these trading securities are reflected in net investment income.
The cost of fixed maturities is adjusted for amortization of premiums and accrual of discounts, both computed using the interest method. The cost of fixed maturities and equity securities classified as available-for-sale is adjusted for declines in value that are other than temporary. Impairments in value deemed to be other than temporary are 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.
Real estate investments are reported at cost less accumulated depreciation. The initial cost basis 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 properties are 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 $182.3 million and $87.0 million as of December 31, 2013 and 2012, respectively. Any impairment losses and any changes in valuation allowances are reported in net income.
Commercial and residential mortgage loans are generally reported at cost adjusted for amortization of premiums and accrual of discounts, computed using the interest method, net of valuation allowances. 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. Any changes in the valuation allowances are reported in net income as net realized capital gains (losses). We measure impairment based upon the difference between carrying value and estimated value less cost to sell. Estimated value is based on either the present value of expected cash flows discounted at the loan's effective interest rate, the loan's observable market price or the fair value of the collateral. If foreclosure is probable, the measurement of any valuation allowance is based upon the fair value of the collateral.
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): other-than-temporary impairments of securities and subsequent realized recoveries, mark-to-market adjustments on certain trading securities, mark-to-market adjustments on certain seed money investments, fair value hedge and cash flow hedge ineffectiveness, mark-to-market adjustments on derivatives not designated as hedges, changes in the mortgage loan valuation allowance provision and impairments of real estate held for investment. Investment gains and losses on sales of certain real estate held for sale that do not meet the criteria for classification as a discontinued operation, mark-to-market adjustments on certain equity securities, trading that represent mandatory required investments and mark-to-market adjustments on trading securities that support investment strategies that involve the active and frequent purchase and sale of fixed maturities are reported as net investment income and are excluded from net realized capital gains (losses).
Policy loans and other investments, excluding investments in unconsolidated entities and commercial mortgage loans of consolidated VIEs for which the fair value option was elected, are primarily reported at cost.
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 interest rate swaps, interest rate options, swaptions, currency swaps, currency forwards, currency options, equity options, futures, credit default swaps and total return swaps. Derivatives may be exchange traded, cleared through centralized clearinghouses, or contracted in the over-the-counter market without being cleared. 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 15, 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.
Fair Value Hedges.    When a derivative is designated as a fair value hedge and is determined to be highly effective, changes in its fair value, along with changes in the fair value of the hedged asset, liability or firm commitment attributable to the hedged risk, are reported in net realized capital gains (losses). Any difference between the net change in fair value of the derivative and the hedged item represents hedge ineffectiveness.
Cash Flow Hedges.    When a derivative is designated as a cash flow hedge and is determined to be highly effective, changes in its fair value are recorded as a component of OCI. Any hedge ineffectiveness is recorded immediately in net income. At the time the variability of cash flows being hedged impacts net income, the related portion of deferred gains or losses on the derivative instrument is reclassified and reported in net income.
Net Investment in a Foreign Operation Hedge.    When a derivative is used as a hedge of a net investment in a foreign operation, its change in fair value, to the extent effective as a hedge, is recorded as a component of OCI. Any hedge ineffectiveness is recorded immediately in net income. If the foreign operation is sold or upon complete or substantially complete liquidation, the deferred gains or losses on the derivative instrument are reclassified into net income.
Non-Hedge Derivatives.    If a derivative does not qualify or is not designated for hedge accounting, all changes in fair value are reported in net income without considering the changes in the fair value of the economically associated assets or liabilities.
Hedge Documentation and Effectiveness Testing.    At inception, we formally document all relationships between hedging instruments and hedged items, as well as our risk management objective and strategy for undertaking various hedge transactions. This process includes associating all derivatives designated as fair value or cash flow hedges with specific assets or liabilities on the statement of financial position or with specific firm commitments or forecasted transactions. Effectiveness of the hedge is formally assessed at inception and throughout the life of the hedging relationship. Even if a derivative is highly effective and qualifies for hedge accounting treatment, the hedge might have some ineffectiveness.
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.    We prospectively discontinue hedge accounting when (1) the criteria to qualify for hedge accounting is no longer met, e.g., a derivative is determined to no longer be highly effective in offsetting the change in fair value or cash flows of a hedged item; (2) the derivative expires, is sold, terminated or exercised or (3) we remove the designation of the derivative being the hedging instrument for a fair value or cash flow hedge.
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 OCI 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 OCI into net income.
Embedded Derivatives.    We purchase and issue certain financial instruments and products that contain a derivative that is embedded in the financial instrument or product. We assess whether this embedded derivative is clearly and closely related to the asset or liability that serves as its host contract. If we deem that the embedded derivative's terms are not clearly and closely related to the host contract, and a separate instrument with the same terms would qualify as a derivative instrument, the derivative is bifurcated from that contract and held at fair value on the consolidated statements of financial position, with changes in fair value reported in net income.
Contractholder and Policyholder Liabilities
Contractholder and policyholder liabilities (contractholder funds, future policy benefits and claims and other policyholder funds) include reserves for investment contracts and reserves for universal life, term life insurance, participating traditional individual life insurance, group life insurance, health insurance and disability income policies, as well as 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 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 contracts that contain no lapse guarantee features, or annuities with guaranteed minimum death benefits.
Reserves for 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.
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 12%, 13% and 15% of our life insurance in force and 43%, 47% and 50% of the number of life insurance policies in force at December 31, 2013, 2012 and 2011, respectively. Participating business represented approximately 40%, 43% and 47% of life insurance premiums for the years ended December 31, 2013, 2012 and 2011, 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 operations over the estimated lives of these policies and contracts in relation to the emergence of estimated gross profit margins.
The liability for unpaid disability and health claims 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 that 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.
Recognition of Premiums and Other Considerations, Fees and Other Revenues and Benefits
Traditional individual life insurance products include those products with fixed and guaranteed premiums and benefits and consist principally of whole life and term life insurance policies. 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 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 and health insurance 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 for group life and health insurance products 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 services provided to retail and institutional clients based largely upon contractual rates applied to the market value of the client's portfolio. Additionally, fees and other revenues are earned for administrative services performed including recordkeeping and reporting services for retirement savings plans. 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
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 of contract acquisition 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 operations as incurred.
DAC for universal life-type insurance contracts, participating life insurance policies and certain investment contracts are being amortized over the lives of the policies and contracts in relation to the emergence of estimated gross profits ("EGPs") or, in certain circumstances, estimated gross revenues. This amortization is adjusted in the current period when EGPs or estimated gross revenues are revised. For individual variable life insurance, individual variable annuities and group annuities that have separate account U.S. equity investment options, we utilize a mean reversion method (reversion to the mean assumption), a common industry practice, to determine the future domestic equity market growth assumption used for the amortization of DAC. The DAC of nonparticipating term life insurance and individual disability policies are being amortized over the premium-paying period of the related policies using assumptions consistent with those used in computing policyholder liabilities.
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 is necessary, DAC would be written off to the extent that it is determined that future policy premiums and investment income or gross profits are not adequate to cover related losses and expenses.
DAC on long-term service contracts are amortized in proportion to the revenue recognized or straight-line if no pattern of revenue recognition can be reasonably predicted. We amortize capitalized costs of long-term service contracts on a straight-line basis over the expected contract life.
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
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 statement of financial position.
Reinsurance
We enter into reinsurance agreements with other companies in the normal course of business. 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. At December 31, 2013 and 2012, our largest exposures to a single third-party reinsurer was in our life insurance business, which totaled $35.9 billion and $29.7 billion of life insurance in force, representing 17% and 18% of total net life insurance in force, respectively. The reinsurance recoverable relating to paid and unpaid claims associated to this single third party reinsurer recorded in our consolidated statements of financial position was $31.3 million and $26.1 million at December 31, 2013 and 2012, respectively.
The effects of reinsurance on premiums and other considerations and policy and contract benefits were as follows:
	For the year ended
	December 31,
	2013			2012			2011
	(in millions)
Premiums and other considerations:
Direct	$	3,524.80		$	3,554.10		$	3,205.60
Assumed		2.5			2.6			3
Ceded		(373.2	)		(337.3	)		(317.6	)
Net premiums and other considerations	$	3,154.10		$	3,219.40		$	2,891.00
Benefits, claims and settlement expenses:
Direct	$	4,933.30		$	5,268.60		$	4,926.50
Assumed		32.2			33.9			34
Ceded		(281.9	)		(178.6	)		(343.9	)
Net benefits, claims and settlement expenses	$	4,683.60		$	5,123.90		$	4,616.60
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 statement 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 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.
At December 31, 2013 and December 31, 2012, the separate accounts include a separate account valued at $223.1 million and $148.3 million, respectively, which primarily includes 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 to eligible participants of the qualified plan. 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
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 and net operating losses 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 operations in the period in which the change is enacted.
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
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 to which it was assigned. A reporting unit is an operating segment or a business one level below that 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 consists of 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
Basic earnings per common share is calculated by dividing 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.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2013
Acquisition	'
Acquisition	'
	2. Acquisition
	On February 4, 2013, we completed the purchase of Cuprum, a premier pension manager in Chile that will grow our ability to offer customers in Chile unmatched pension savings and retirement solutions. Our acquisition agreement required Empresas Penta S.A. and Inversiones Banpenta Limitada to sell their 63% ownership in Cuprum pursuant to a public tender offer that also included the remaining 37% of publicly traded shares. As a result of the public tender offer, we initially acquired a 91.55% ownership stake in Cuprum for a purchase price of $1.3 billion. Cuprum is consolidated within the Principal International segment.
	A summary of the fair values of the net assets acquired as of February 4, 2013, based upon current valuation estimates, is as follows (in millions):
	Assets
	Equity securities, available-for-sale	$	3.2
	Equity securities, trading		340.5
	Real estate		1.9
	Other investments		24.2
	Cash and cash equivalents		3.5
	Premiums due and other receivables		1.4
	Property and equipment		19.6
	Goodwill		631.8
	Other intangibles		671.3
	Separate account assets		33,919.40
	Other assets		27.3
	Total assets		35,644.10
	Liabilities
	Short-term debt		5
	Long-term debt		114.6
	Separate account liabilities		33,919.40
	Other liabilities		228
	Total liabilities		34,267.00
	Noncontrolling interest		113.6
	Net assets acquired	$	1,263.50
	Of the acquired intangible assets, $631.8 million was assigned to goodwill and is not subject to amortization. The goodwill is largely related to future sales anticipated from our internal workforce and entity-specific revenue synergies that will be generated by combining Cuprum with our existing businesses.
	Of the remaining acquired intangible assets, $185.2 million was assigned to trade name, which is not subject to amortization, and $486.1 million was assigned to customer relationships, which is subject to amortization over a 15-year useful life.
	See Note 4, Variable Interest Entities, for further information on Cuprum's separate account assets and liabilities.
	The following (unaudited) pro forma consolidated results of operations have been prepared to show the impact of the acquisition of Cuprum as if the acquisition had occurred January 1, 2013, for the year ended December 31, 2013, as if the acquisition had occurred on January 1, 2012, for the year ended December 31, 2012 and as if the acquisition had occurred on January 1, 2011, for the year ended December 31, 2011. This supplemental pro forma information has been prepared for comparative purposes and is not necessarily indicative of the results of operations that actually would have been achieved had the acquisition been consummated as of that time, nor is it intended to be a projection of future results.
		For the year ended
		December 31,
		2013		2012		2011
		(in millions,
		except per share data)
	Total revenues	$	9,339.40	$	9,424.40	$	8,840.30
	Net income		956.6		939.3		753.2
	Basic earnings per common share		3.25		3.16		2.39
	Diluted earnings per common share		3.21		3.13		2.37
	The (unaudited) total revenues and net income of Cuprum included in the consolidated statement of operations from the acquisition date to the period ended December 31, 2013, were as follows:
		For the year ended,
		December 31, 2013
	Total revenues	$	186.4
	Net income		87

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2013
Goodwill and Other Intangible Assets	'
Goodwill and Other Intangible Assets	'
	3. Goodwill and Other Intangible Assets
	Goodwill
	The changes in the carrying amount of goodwill reported in our segments were as follows:
		Retirement			Principal		Principal			U.S.			Corporate		Consolidated
		and Investor			Global		International			Insurance
		Services			Investors					Solutions
		(in millions)
	Balance at January 1, 2012	$	72.6		$	237	$	127.8		$	44.9		$	—	$	482.3
	Goodwill from acquisitions		—			—		63.3			10.5			—		73.8
	Foreign currency		—			2.9		(11.6	)		—			—		(8.7	)
	Other		(4.0	)		—		—			—			—		(4.0	)
	Balance at December 31, 2012		68.6			239.9		179.5			55.4			—		543.4
	Goodwill from acquisitions		—			—		631.8			2.6			—		634.4
	Goodwill disposed		—			—		—			(1.4	)		—		(1.4	)
	Foreign currency		—			1.2		(81.3	)		—			—		(80.1	)
	Other		4			—		—			—			—		4
	Balance at December 31, 2013	$	72.6		$	241.1	$	730		$	56.6		$	—	$	1,100.30
	Finite Lived Intangible Assets
	Amortized intangible assets that continue to be subject to amortization over a weighted average remaining expected life of 14 years were as follows:
		December 31,
		2013								2012
		Gross			Accumulated		Net			Gross			Accumulated		Net
		carrying			amortization		carrying			carrying			amortization		carrying
		value					value			value					value
		(in millions)
	Present value of future profits	$	13.5		$	6.7	$	6.8		$	13.5		$	6.1	$	7.4
	Other finite lived intangible assets		858.8			262.9		595.9			436.1			224.1		212
	Total amortized intangible assets	$	872.3		$	269.6	$	602.7		$	449.6		$	230.2	$	219.4
	During 2013 and 2012, we fully amortized other finite lived intangible assets of $5.2 million and $5.0 million, respectively. We had no fully amortized other finite lived intangible assets in 2011.
	Other Finite Lived Intangible Assets.    The amortization expense for intangible assets with finite useful lives was $48.0 million, $22.7 million and $20.1 million for 2013, 2012 and 2011, respectively. At December 31, 2013, the estimated amortization expense for the next five years is as follows (in millions):
	Year ending December 31:
	2014	$	52.3
	2015		50.9
	2016		50.1
	2017		49.2
	2018		48
	Indefinite Lived Intangible Assets
	The net carrying amount of unamortized indefinite lived intangible assets was $856.3 million and $695.3 million as of December 31, 2013 and 2012, respectively. As of both December 31, 2013 and 2012, $608.0 million relates to investment management contracts associated with our acquisition of WM Advisors, Inc. in 2006. In addition, as of December 31, 2013, $185.2 million relates to trade name intangibles associated with our acquisition of Cuprum in 2013.

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2013
Variable Interest Entities	'
Variable Interest Entities	'
	4. Variable Interest Entities
	We have relationships with and may have a variable interest in various types of special purpose entities. Following is a discussion of our interest in entities that meet the definition of a VIE. When we are the primary beneficiary, we are required to consolidate the entity in our financial statements. The primary beneficiary of a VIE is defined as 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. On an ongoing basis, we assess whether we are the primary beneficiary of VIEs we have relationships with.
	Consolidated Variable Interest Entities
	Grantor Trusts
	We contributed undated subordinated floating rate notes to three grantor trusts. The trusts separated the cash flows by issuing an interest-only certificate and a residual certificate related to each note contributed. Each interest-only certificate entitles the holder to interest on the stated note for a specified term, while the residual certificate entitles 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 have determined these grantor trusts are VIEs due to insufficient equity to sustain them. We determined we are the primary beneficiary as a result of our contribution of securities into the trusts and our continuing interest in the trusts.
	Collateralized Private Investment Vehicle
	We invest in synthetic collateralized debt obligations, collateralized bond obligations, collateralized loan obligations and other collateralized structures, which are VIEs due to insufficient equity to sustain the entities (collectively known as "collateralized private investment vehicles"). The performance of the notes of these structures is primarily linked to a synthetic portfolio by derivatives; each note has a specific loss attachment and detachment point. The notes and related derivatives are collateralized by a pool of permitted investments. The investments are held by a trustee and can only be liquidated to settle obligations of the trusts. These obligations primarily include derivatives and the notes due at maturity or termination of the trusts. We determined we are the primary beneficiary for one of these entities because we act as the investment manager of the underlying portfolio and we have an ownership interest.
	Commercial Mortgage-Backed Securities
	In September 2000, we sold commercial mortgage loans to a real estate mortgage investment conduit trust. The trust issued various commercial mortgage-backed securities ("CMBS") certificates using the cash flows of the underlying commercial mortgages it purchased. This is considered a VIE due to insufficient equity to sustain itself. We have determined we are the primary beneficiary as we retained the special servicing role for the assets within the trust as well as the ownership of the bond class that controls the unilateral kick out rights of the special servicer.
	Mandatory Retirement Savings
	As a result of our first quarter 2013 acquisition of Cuprum, we hold an equity interest in mandatory privatized social security funds in which we provide asset management services. We determined that the mandatory privatized social security funds, which include contributors 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 that we are the primary beneficiary through our power to make decisions and our 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 client 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.
	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 are as follows:
		Grantor trusts		Collateralized		CMBS		Mandatory		Total
				private investment				retirement
				vehicle				savings
		(in millions)
	December 31, 2013
	Fixed maturities, available-for-sale	$	272	$	—	$	—	$	—	$	272
	Fixed maturities, trading		—		110.4		—		—		110.4
	Equity securities, trading		—		—		—		327.2		327.2
	Other investments		—		—		68.1		—		68.1
	Accrued investment income		0.3		—		0.6		—		0.9
	Separate account assets		—		—		—		32,824.70		32,824.70
	Total assets	$	272.3	$	110.4	$	68.7	$	33,151.90	$	33,603.30
	Deferred income taxes	$	1.5	$	—	$	—	$	—	$	1.5
	Separate account liabilities		—		—		—		32,824.70		32,824.70
	Other liabilities (1)		217.2		93.8		31.4		—		342.4
	Total liabilities	$	218.7	$	93.8	$	31.4	$	32,824.70	$	33,168.60
	December 31, 2012
	Fixed maturities, available-for-sale	$	194.6	$	—	$	—	$	—	$	194.6
	Fixed maturities, trading		—		110.4		—		—		110.4
	Equity securities, trading		—		—		—		—		—
	Other investments		—		—		80.3		—		80.3
	Accrued investment income		0.5		—		0.6		—		1.1
	Total assets	$	195.1	$	110.4	$	80.9	$	—	$	386.4
	Deferred income taxes	$	1.8	$	—	$	—	$	—	$	1.8
	Other liabilities (1)		152.4		104.8		45.7		—		302.9
	Total liabilities	$	154.2	$	104.8	$	45.7	$	—	$	304.7
	-1
	Grantor trusts contain an embedded derivative of a forecasted transaction to deliver the underlying securities; the collateralized private investment vehicle includes derivative liabilities and an obligation to redeem notes at maturity or termination of the trust; and CMBS includes an obligation to the bondholders.
	We did not provide financial or other support to investees designated as VIEs for the years ended December 31, 2013 and 2012.
	Unconsolidated Variable Interest Entities
	Invested Securities
	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 and other investments in the consolidated statements of financial position and are described below.
	Unconsolidated VIEs include CMBS, residential mortgage-backed pass-through securities ("RMBS") and other asset-backed securities ("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 any of 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.
	As previously discussed, we invest in several types of collateralized private investment vehicles, which are VIEs. These include cash and synthetic structures that we do not manage. We have determined we are not the primary beneficiary of these collateralized private investment vehicles 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 various VIE trusts as a debt holder. All of these entities are classified as VIEs due to insufficient equity to sustain them. 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, some of which are classified as VIEs. The returns from the partnerships are in the form of income tax credits and investment income. These entities are classified as VIEs as the general partner does not have an equity investment at risk in the entity. We have determined we are not the primary beneficiary because we are not the general partner, who makes all the significant decisions for the entity.
	The carrying value and maximum loss exposure for our unconsolidated VIEs were as follows:
		Asset carrying value		Maximum exposure to
				loss (1)
		(in millions)
	December 31, 2013
	Fixed maturities, available-for-sale:
	Corporate	$	523.4	$	448.2
	Residential mortgage-backed pass-through securities		2,845.20		2,799.10
	Commercial mortgage-backed securities		4,026.40		4,078.00
	Collateralized debt obligations		363.4		391.9
	Other debt obligations		4,167.80		4,157.50
	Fixed maturities, trading:
	Residential mortgage-backed pass-through securities		47.5		47.5
	Commercial mortgage-backed securities		1.8		1.8
	Collateralized debt obligations		59.6		59.6
Other debt obligations		1.2		1.2
Other investments:
Other limited partnership interests		123.5		123.5
December 31, 2012
Fixed maturities, available-for-sale:
Corporate	$	523.2	$	403.7
Residential mortgage-backed pass-through securities		3,226.70		3,022.70
Commercial mortgage-backed securities		3,897.40		4,094.80
Collateralized debt obligations		379.2		428.8
Other debt obligations		3,779.20		3,756.90
Fixed maturities, trading:
Residential mortgage-backed pass-through securities		77.7		77.7
Commercial mortgage-backed securities		2.8		2.8
Collateralized debt obligations		56.4		56.4
Other debt obligations		3.2		3.2
Other investments:
Other limited partnership interests		136.2		136.2
-1
Our risk of loss is limited to our initial investment measured at amortized cost for fixed maturities, available-for-sale and other investments. Our risk of loss is limited to our investment measured at fair value for our fixed maturities, trading.
Sponsored Investment Funds
We are the investment manager for certain money market mutual funds that are deemed to be VIEs. We are not the primary beneficiary of these VIEs since our involvement is limited primarily to being a service provider, and our variable interest does not absorb the majority of the variability of the entities' net assets. As of December 31, 2013 and December 31, 2012, these VIEs held $1.4 billion and $1.5 billion in total assets, respectively. We have no contractual obligation to contribute to the funds.
We provide asset management and other services to certain investment structures that are considered VIEs as we generally earn performance-based management fees. We are not the primary beneficiary of these entities as we do not have the obligation to absorb losses of the entities that could be potentially significant to the VIE or the right to receive benefits from these entities that could be potentially significant.

Investments

Investments	12 Months Ended
	Dec. 31, 2013
Investments	'
Investments	'
	5. Investments
	Fixed Maturities and Equity Securities
	The amortized cost, gross unrealized gains and losses, other-than-temporary impairments in AOCI and fair value of fixed maturities and equity securities available-for-sale are summarized as follows:
		Amortized			Gross			Gross			Fair value			Other-than-
		cost			unrealized			unrealized						temporary
					gains			losses						impairments in
														AOCI (1)
		(in millions)
	December 31, 2013
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	818.2		$	12.7		$	50.4		$	780.5		$	—
	Non-U.S. government and agencies		853.2			148.8			5.2			996.8			—
	States and political subdivisions		3,622.80			120.9			85.7			3,658.00			—
	Corporate		30,280.60			1,958.80			320.4			31,919.00			17.1
	Residential mortgage-backed pass-through securities		2,799.10			92.8			46.7			2,845.20			—
	Commercial mortgage-backed securities		4,078.00			170.6			222.2			4,026.40			183.4
	Collateralized debt obligations		391.9			6			34.5			363.4			0.7
	Other debt obligations		4,157.50			51.8			41.5			4,167.80			76.3
	Total fixed maturities, available-for-sale	$	47,001.30		$	2,562.40		$	806.6		$	48,757.10		$	277.5
	Total equity securities, available-for-sale	$	113.8		$	10		$	13.3		$	110.5
	December 31, 2012
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	911.4		$	33.2		$	0.3		$	944.3		$	—
	Non-U.S. government and agencies		944.9			264.3			0.9			1,208.30			—
	States and political subdivisions		2,940.40			241.1			2.7			3,178.80			—
	Corporate		31,615.40			3,029.90			319.9			34,325.40			19.5
	Residential mortgage-backed pass-through securities		3,022.70			204.4			0.4			3,226.70			—
	Commercial mortgage-backed securities		4,094.80			241.7			439.1			3,897.40			195.4
	Collateralized debt obligations		428.8			7			56.6			379.2			4.3
	Other debt obligations		3,756.90			73.5			51.2			3,779.20			82.8
	Total fixed maturities, available-for-sale	$	47,715.30		$	4,095.10		$	871.1		$	50,939.30		$	302
	Total equity securities, available-for-sale	$	132.4		$	12.6		$	8.5		$	136.5
	-1
	Excludes $148.6 million and $95.0 million as of December 31, 2013 and December 31, 2012, respectively, 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 at December 31, 2013, by expected maturity, were as follows:
		Amortized			Fair
		cost			value
		(in millions)
	Due in one year or less	$	2,977.30		$	3,019.00
	Due after one year through five years		12,674.40			13,297.30
	Due after five years through ten years		8,669.80			9,091.20
	Due after ten years		11,253.30			11,946.80
	Subtotal		35,574.80			37,354.30
	Mortgage-backed and other asset-backed securities		11,426.50			11,402.80
	Total	$	47,001.30		$	48,757.10
	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 categories of net investment income are summarized as follows:
		For the year ended December 31,
		2013			2012			2011
		(in millions)
	Fixed maturities, available-for-sale	$	2,321.30		$	2,454.80		$	2,596.20
	Fixed maturities, trading		22.5			30.2			64.7
	Equity securities, available-for-sale		7.6			8.6			10.5
	Equity securities, trading		19.8			6.6			4.4
	Mortgage loans		611.5			635.8			649.2
	Real estate		61.2			71.4			74.2
	Policy loans		49.9			53.7			58.2
	Cash and cash equivalents		14			9.6			8.5
	Derivatives		(115.2	)		(131.2	)		(196.1	)
	Other		222			196.6			188.5
	Total		3,214.60			3,336.10			3,458.30
	Investment expenses		(76.2	)		(81.2	)		(83.0	)
Net investment income	$	3,138.40		$	3,254.90		$	3,375.30
Net Realized Capital Gains and Losses
	For the year ended December 31,
	2013			2012			2011
	(in millions)
Fixed maturities, available-for-sale:
Gross gains	$	45.5		$	31		$	26.4
Gross losses		(122.1	)		(144.9	)		(158.8	)
Other-than-temporary impairment losses reclassified to (from) OCI		(24.5	)		17.3			(49.7	)
Hedging, net		(115.5	)		(27.5	)		130.5
Fixed maturities, trading		(7.1	)		2.2			(6.7	)
Equity securities, available-for-sale:
Gross gains		0.8			0.6			2.2
Gross losses		(0.3	)		(0.9	)		(6.4	)
Equity securities, trading		26.9			34.1			20.3
Mortgage loans		(15.8	)		(51.3	)		(42.1	)
Derivatives		(23.0	)		(10.9	)		(180.5	)
Other		9.9			264.4			142.5
Net realized capital gains (losses)	$	(225.2	)	$	114.1		$	(122.3	)
Proceeds from sales of investments (excluding call and maturity proceeds) in fixed maturities, available-for-sale were $1,773.0 million, $1,228.6 million and $881.7 million in 2013, 2012 and 2011, respectively.
Other-Than-Temporary Impairments
We have a process in place to identify fixed maturity and equity securities that could potentially have a credit impairment that is other than temporary. 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 are reviewed to determine whether an other-than-temporary decline in value exists and whether losses should be recognized. We consider relevant facts and circumstances in evaluating whether a credit or interest-related impairment of a security is other than temporary. Relevant facts and circumstances considered include: (1) the extent and length of time the fair value has been 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; (5) for fixed maturities, 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 and (6) for equity securities, our ability and intent to hold the security for a period of time that allows for the recovery in value. To the extent we determine that a security is deemed to be other than temporarily impaired, an impairment loss is recognized.
Impairment losses on equity securities are recognized in net income and are measured as the difference between amortized cost and fair value. The way in which impairment losses on fixed maturities are recognized in the financial statements is dependent on the facts and circumstances related to the specific security. If we intend to sell a security or it is more likely than not that we would be required to sell a security before the recovery of its amortized cost, we recognize an other-than-temporary impairment in net income for the difference between amortized cost and fair value. If we do not expect to recover the amortized cost basis, we do not plan to sell the security and if it is 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 is bifurcated. We recognize the credit loss portion in net income and the noncredit loss portion in OCI ("bifurcated OTTI").
Total other-than-temporary impairment losses, net of recoveries from the sale of previously impaired securities, were as follows:
	For the year ended
	December 31,
	2013			2012			2011
	(in millions)
Fixed maturities, available-for-sale	$	(91.2	)	$	(135.5	)	$	(143.8	)
Equity securities, available-for-sale		(0.3	)		(0.4	)		(3.8	)
Total other-than-temporary impairment losses, net of recoveries from the sale of previously impaired securities		(91.5	)		(135.9	)		(147.6	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) OCI (1)		(24.5	)		17.3			(49.7	)
Net impairment losses on available-for-sale securities	$	(116.0	)	$	(118.6	)	$	(197.3	)
-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 estimate 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 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.
The following table provides a rollforward of accumulated credit losses for fixed maturities with bifurcated credit losses. 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,
	2013			2012			2011
	(in millions)
Beginning balance	$	(335.2	)	$	(434.8	)	$	(325.7	)
Credit losses for which an other-than-temporary impairment was not previously recognized		(15.1	)		(20.7	)		(37.8	)
Credit losses for which an other-than-temporary impairment was previously recognized		(75.9	)		(80.0	)		(135.6	)
Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold		177.6			191.9			68.2
Net reduction (increase) for positive changes in cash flows expected to be collected and amortization (1)		12.6			8.4			(3.9	)
Ending balance	$	(236.0	)	$	(335.2	)	$	(434.8	)
-1
Amounts are recognized in net investment income.
Gross Unrealized Losses for Fixed Maturities and Equity Securities
For fixed maturities and equity securities available-for-sale with unrealized losses, including other-than-temporary impairment losses reported in OCI, 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 are summarized as follows:
	December 31, 2013
	Less than twelve						Greater than or						Total
	months						equal to twelve
							months
	Fair			Gross			Fair			Gross			Fair		Gross
	value			unrealized			value			unrealized			value		unrealized
				losses						losses					losses
	(in millions)
Fixed maturities, available-for-sale:
U.S. government and agencies	$	526.8		$	49.6		$	9.2		$	0.8		$	536	$	50.4
Non-U.S. governments		78.1			5.1			5.8			0.1			83.9		5.2
States and political subdivisions		1,338.60			75.3			46.1			10.4			1,384.70		85.7
Corporate		4,087.90			155.4			1,278.10			165			5,366.00		320.4
Residential mortgage-backed pass- through securities		1,150.30			38.2			85.9			8.5			1,236.20		46.7
Commercial mortgage-backed securities		683.7			15.3			495.6			206.9			1,179.30		222.2
Collateralized debt obligations		88.8			1.4			47.4			33.1			136.2		34.5
Other debt obligations		1,359.00			16.1			287.9			25.4			1,646.90		41.5
Total fixed maturities, available-for-sale	$	9,313.20		$	356.4		$	2,256.00		$	450.2		$	11,569.20	$	806.6
Total equity securities, available-for-sale	$	16.7		$	0.3		$	48.3		$	13		$	65	$	13.3
Of the total amounts, Principal Life Insurance Company's ("Principal Life") consolidated portfolio represented $10,905.4 million in available-for-sale fixed maturities with gross unrealized losses of $752.5 million. Of those fixed maturity securities in Principal Life's consolidated portfolio with a gross unrealized loss position, 87% were investment grade (rated AAA through BBB-) with an average price of 94 (carrying value/amortized cost) at December 31, 2013. Gross unrealized losses in our fixed maturities portfolio decreased slightly during the year ended December 31, 2013, due to spread improvements.
For those securities that had been in a continuous unrealized loss position for less than twelve months, Principal Life's consolidated portfolio held 1,154 securities with a carrying value of $8,899.5 million and unrealized losses of $339.8 million reflecting an average price of 96 at December 31, 2013. Of this portfolio, 94% was investment grade (rated AAA through BBB-) at December 31, 2013, with associated unrealized losses of $325.9 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 359 securities with a carrying value of $2,005.9 million and unrealized losses of $412.7 million. The average rating of this portfolio was BBB- with an average price of 83 at December 31, 2013. Of the $412.7 million in unrealized losses, the commercial mortgage-backed securities sector accounts for $206.9 million in unrealized losses with an average price of 71 and an average credit rating of BB-. The remaining unrealized losses consist primarily of $127.6 million within the corporate sector at December 31, 2013. The average price of the corporate sector was 89 and the average credit rating was BBB+. 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 maturity, we did not consider these investments to be other-than-temporarily impaired at December 31, 2013.
	December 31, 2012
	Less than twelve						Greater than or						Total
	months						equal to twelve
							months
	Fair			Gross			Fair			Gross			Fair		Gross
	value			unrealized			value			unrealized			value		unrealized
				losses						losses					losses
	(in millions)
Fixed maturities, available-for-sale:
U.S. government and agencies	$	115.4		$	0.3		$	—		$	—		$	115.4	$	0.3
Non-U.S. governments		17.3			0.2			13.4			0.7			30.7		0.9
States and political subdivisions		235.3			2.1			8.8			0.6			244.1		2.7
Corporate		831.8			10.6			1,961.70			309.3			2,793.50		319.9
Residential mortgage-backed pass- through securities		70.4			0.3			2.4			0.1			72.8		0.4
Commercial mortgage-backed securities		98.9			3.3			785			435.8			883.9		439.1
Collateralized debt obligations		72.2			1			133.8			55.6			206		56.6
Other debt obligations		235.6			2			414.9			49.2			650.5		51.2
Total fixed maturities, available-for-sale	$	1,676.90		$	19.8		$	3,320.00		$	851.3		$	4,996.90	$	871.1
Total equity securities, available-for-sale	$	5.8		$	0.1		$	52.9		$	8.4		$	58.7	$	8.5
Of the total amounts, Principal Life's consolidated portfolio represented $4,419.4 million in available-for-sale fixed maturities with gross unrealized losses of $825.7 million. Of those fixed maturity securities in Principal Life's consolidated portfolio with a gross unrealized loss position, 71% were investment grade (rated AAA through BBB-) with an average price of 84 (carrying value/amortized cost) at December 31, 2012. Gross unrealized losses in our fixed maturities portfolio decreased during the year ended December 31, 2012, due to a tightening of credit spreads, primarily in the corporate and commercial mortgage-backed securities sectors.
For those securities that had been in a continuous unrealized loss position for less than twelve months, Principal Life's consolidated portfolio held 224 securities with a carrying value of $1,382.1 million and unrealized losses of $16.2 million reflecting an average price of 99 at December 31, 2012. Of this portfolio, 89% was investment grade (rated AAA through BBB-) at December 31, 2012, with associated unrealized losses of $13.3 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 488 securities with a carrying value of $3,037.3 million and unrealized losses of $809.5 million. The average rating of this portfolio was BBB- with an average price of 79 at December 31, 2012. Of the $809.5 million in unrealized losses, the commercial mortgage-backed securities sector accounts for $435.8 million in unrealized losses with an average price of 64 and an average credit rating of BB+. The remaining unrealized losses consist primarily of $268.1 million within the corporate sector at December 31, 2012. The average price of the corporate sector was 86 and the average credit rating was BBB. 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 maturity, we did not consider these investments to be other-than-temporarily impaired at December 31, 2012.
Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments
The net unrealized gains and losses on investments in fixed maturities available-for-sale, equity securities available-for-sale and derivative instruments in cash flow hedge relationships are reported as a separate component 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, reinsurance assets or liabilities, sales inducements, unearned revenue reserves, changes in policyholder liabilities and applicable income taxes was as follows:
	December 31, 2013			December 31, 2012
	(in millions)
Net unrealized gains on fixed maturities, available-for-sale (1)	$	2,064.00		$	3,562.50
Noncredit component of impairment losses on fixed maturities, available-for-sale		(277.5	)		(302.0	)
Net unrealized gains (losses) on equity securities, available-for-sale		(3.3	)		4.1
Adjustments for assumed changes in amortization patterns		(265.9	)		(515.2	)
Adjustments for assumed changes in policyholder liabilities		(602.5	)		(1,198.7	)
Net unrealized gains on derivative instruments		56			90.7
Net unrealized gains on equity method subsidiaries and noncontrolling interest adjustments		71.8			191.3
Provision for deferred income taxes		(342.0	)		(597.0	)
Net unrealized gains on available-for-sale securities and derivative instruments	$	700.6		$	1,235.70
-1
Excludes net unrealized gains (losses) on fixed maturities, available-for-sale included in fair value hedging relationships.
Mortgage Loans
Mortgage loans consist of commercial and residential mortgage loans. We evaluate risks inherent in our commercial mortgage loans in two classes: (1) brick and mortar property loans, where we analyze the property's rent payments as support for the loan, and (2) credit tenant loans ("CTL"), where we rely on the credit analysis of the tenant for the repayment of the loan. We evaluate risks inherent in our residential mortgage loan portfolio in two classes: (1) home equity mortgages and (2) first lien mortgages. The carrying amount of our mortgage loan portfolio was as follows:
	December 31, 2013			December 31, 2012
	(in millions)
Commercial mortgage loans	$	10,327.70		$	10,235.10
Residential mortgage loans		1,275.70			1,382.00
Total amortized cost		11,603.40			11,617.10
Valuation allowance		(69.8	)		(97.4	)
Total carrying value	$	11,533.60		$	11,519.70
We periodically purchase mortgage loans as well as sell mortgage loans we have originated. We purchased $157.2 million, $153.0 million and $40.6 million of residential mortgage loans in 2013, 2012 and 2011, respectively. We sold $0.0 million, $14.2 million and $18.4 million of residential mortgage loans in 2013, 2012 and 2011, respectively. We purchased $166.1 million, $149.1 million and $50.3 million of commercial mortgage loans in 2013, 2012 and 2011, respectively. We sold $13.0 million, $31.1 million and $0.0 million of commercial mortgage loans in 2013, 2012 and 2011, respectively.
Our commercial mortgage loan portfolio consists primarily of non-recourse, fixed rate mortgages on stabilized properties. Our commercial mortgage loan portfolio is diversified by geographic region and specific collateral property type as follows:
	December 31, 2013						December 31, 2012
	Amortized			Percent			Amortized			Percent
	cost			of total			cost			of total
	($ in millions)
Geographic distribution
New England	$	528.5			5.1	%	$	536.6			5.2	%
Middle Atlantic		2,489.00			24.1			2,233.40			21.8
East North Central		519.9			5			635.6			6.2
West North Central		302.9			2.9			377.3			3.7
South Atlantic		1,949.50			18.9			2,135.00			20.9
East South Central		192.8			1.9			244.8			2.4
West South Central		830.3			8			767.9			7.5
Mountain		747.1			7.2			726.6			7.1
Pacific		2,722.50			26.5			2,562.30			25
International		45.2			0.4			15.6			0.2
Total	$	10,327.70			100	%	$	10,235.10			100	%
Property type distribution
Office	$	3,360.50			32.6	%	$	3,078.80			30.1	%
Retail		2,668.50			25.8			2,928.30			28.6
Industrial		1,766.20			17.1			1,765.50			17.2
Apartments		1,911.20			18.5			1,685.90			16.5
Hotel		333.1			3.2			445.8			4.4
Mixed use/other		288.2			2.8			330.8			3.2
Total	$	10,327.70			100	%	$	10,235.10			100	%
Our residential mortgage loan portfolio is composed of home equity mortgages with an amortized cost of $394.9 million and $495.7 million and first lien mortgages with an amortized cost of $880.8 million and $886.3 million as of December 31, 2013 and December 31, 2012, respectively. Our residential home equity mortgages are concentrated in the United States and are generally second lien mortgages comprised of closed-end loans and lines of credit. The majority of our first lien loans are concentrated in the Chilean market.
Mortgage Loan Credit Monitoring
Commercial Credit Risk Profile Based on Internal Rating
We actively monitor and manage our commercial mortgage loan portfolio. All commercial mortgage loans are analyzed regularly and substantially all are internally rated, based on a proprietary risk rating cash flow model, in order to monitor the financial quality of these assets. The model stresses expected cash flows at various levels and at different points in time depending on the durability of the income stream, which includes our assessment of factors such as location (macro and micro markets), tenant quality and lease expirations. Our internal rating analysis presents expected losses in terms of a Standard & Poor's ("S&P") bond equivalent rating. As the credit risk for commercial mortgage loans increases, we adjust our internal ratings downward with loans in the category "B+ and below" having the highest risk for credit loss. Internal ratings on commercial mortgage loans are updated at least annually and potentially more often for certain loans with material changes in collateral value or occupancy and for loans on an internal "watch list".
Commercial mortgage loans that require more frequent and detailed attention than other loans in our portfolio are identified and placed on an internal "watch list". Among the criteria that would indicate a potential problem are imbalances in ratios of loan to value or contract rents to debt service, major tenant vacancies or bankruptcies, borrower sponsorship problems, late payments, delinquent taxes and loan relief/restructuring requests.
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:
	December 31, 2013
	Brick and mortar			CTL			Total
	(in millions)
A- and above	$	8,091.90		$	194.5		$	8,286.40
BBB+ thru BBB-		1,463.70			250			1,713.70
BB+ thru BB-		155.4			0.1			155.5
B+ and below		170.1			2			172.1
Total	$	9,881.10		$	446.6		$	10,327.70
	December 31, 2012
	Brick and mortar			CTL			Total
	(in millions)
A- and above	$	7,257.70		$	231.3		$	7,489.00
BBB+ thru BBB-		1,804.50			294.9			2,099.40
BB+ thru BB-		266.8			1.6			268.4
B+ and below		376			2.3			378.3
Total	$	9,705.00		$	530.1		$	10,235.10
Residential Credit Risk Profile Based on Performance Status
Our residential mortgage loan portfolio is monitored based on performance of the loans. Monitoring on a residential mortgage loan increases when the loan is delinquent or earlier if there is an indication of impairment. We define non-performing residential mortgage loans as loans 90 days or greater delinquent or on non-accrual status.
The amortized cost of our performing and non-performing residential mortgage loans was as follows:
	December 31, 2013
	Home equity			First liens			Total
	(in millions)
Performing	$	378.3		$	862.1		$	1,240.40
Nonperforming		16.6			18.7			35.3
Total	$	394.9		$	880.8		$	1,275.70
	December 31, 2012
	Home equity			First liens			Total
	(in millions)
Performing	$	472.6		$	865		$	1,337.60
Nonperforming		23.1			21.3			44.4
Total	$	495.7		$	886.3		$	1,382.00
Non-Accrual Mortgage Loans
Commercial and residential mortgage loans are placed on non-accrual status if we have concern regarding the collectability of future payments or if a loan has matured without being paid off or extended. Factors considered may include conversations with the borrower, loss of major tenant, bankruptcy of borrower or major tenant, decreased property cash flow for commercial mortgage loans or number of days past due and other circumstances for residential mortgage loans. Based on an assessment as to the collectability of the principal, a determination is made to apply any payments received either against the principal or according to the contractual terms of the loan. When a loan is placed on nonaccrual status, the accrued unpaid interest receivable is reversed against interest income. Accrual of interest resumes after factors resulting in doubts about collectability have improved. Residential first lien mortgages in the Chilean market are carried on accrual for a longer period of delinquency than domestic loans, as assessment of collectability is based on the nature of the loans and collection practices in that market.
The amortized cost of mortgage loans on non-accrual status was as follows:
	December 31, 2013			December 31, 2012
	(in millions)
Commercial:
Brick and mortar	$	33.2		$	44.5
Residential:
Home equity		16.6			23.1
First liens		11.4			13.2
Total	$	61.2		$	80.8
The aging of our mortgage loans, based on amortized cost, was as follows:
	December 31, 2013
	30 - 59 days			60 - 89 days			90 days or			Total			Current		Total		Recorded
	past due			past due			more past			past due					loans		investment
							due										90 days or
																	more and
																	accruing
	(in millions)
Commercial-brick and mortar	$	—		$	—		$	16.7		$	16.7		$	9,864.40	$	9,881.10	$	—
Commercial-CTL		—			—			—			—			446.6		446.6		—
Residential-home equity		4.4			1			3			8.4			386.5		394.9		—
Residential-first liens		32.4			7.4			17.1			56.9			823.9		880.8		7.3
Total	$	36.8		$	8.4		$	36.8		$	82		$	11,521.40	$	11,603.40	$	7.3
	December 31, 2012
	30 - 59 days			60 - 89 days			90 days or			Total past due			Current		Total		Recorded
	past due			past due			more past								loans		investment
							due										90 days or
																	more and
																	accruing
	(in millions)
Commercial-brick and mortar	$	32.8		$	13.7		$	—		$	46.5		$	9,658.50	$	9,705.00	$	—
Commercial-CTL		—			—			—			—			530.1		530.1		—
Residential-home equity		5.7			2.8			3.9			12.4			483.3		495.7		—
Residential-first liens		22.3			5.1			19.8			47.2			839.1		886.3		8.1
Total	$	60.8		$	21.6		$	23.7		$	106.1		$	11,511.00	$	11,617.10	$	8.1
Mortgage Loan Valuation Allowance
We establish a valuation allowance to provide for the risk of credit losses inherent in our portfolio. The valuation allowance includes loan specific reserves for loans that are deemed to be impaired as well as reserves for pools of loans with similar risk characteristics where a property risk or market specific risk has not been identified but for which we anticipate a loss may occur. Mortgage loans on real estate are considered impaired when, based on current information and events, it is probable that we will be unable to collect all amounts due according to contractual terms of the loan agreement. When we determine that a loan is impaired, a valuation allowance is established equal to the difference between the carrying amount of the mortgage loan and the estimated value reduced by the cost to sell. Estimated value is based on either the present value of the expected future cash flows discounted at the loan's effective interest rate, the loan's observable market price or fair value of the collateral. Subsequent changes in the estimated value are reflected in the valuation allowance. Amounts on loans deemed to be uncollectible are charged off and removed from the valuation allowance. The change in the valuation allowance provision is included in net realized capital gains (losses) on our consolidated statements of operations.
The valuation allowance is maintained at a level believed adequate by management to absorb estimated probable credit losses. Management's periodic evaluation and assessment of the valuation allowance adequacy is based on known and inherent risks in the portfolio, adverse situations that may affect a borrower's ability to repay, the estimated value of the underlying collateral, composition of the loan portfolio, portfolio delinquency information, underwriting standards, peer group information, current economic conditions, loss experience and other relevant factors. The evaluation of our impaired loan component is subjective, as it requires the estimation of timing and amount of future cash flows expected to be received on impaired loans.
We review our commercial mortgage loan portfolio and analyze the need for a valuation allowance for any loan that is delinquent for 60 days or more, in process of foreclosure, restructured, on the internal "watch list" or that currently has a valuation allowance. In addition to establishing allowance levels for specifically identified impaired commercial mortgage loans, management determines an allowance for all other loans in the portfolio for which historical experience and current economic conditions indicate certain losses exist. These loans are segregated by major product type and/or risk level with an estimated loss ratio applied against each product type and/or risk level. The loss ratio is generally based upon historic loss experience for each loan type as adjusted for certain current environmental factors management believes to be relevant.
For our residential mortgage loan portfolio, we separate the loans into several homogeneous pools, each of which consist of loans of a similar nature including but not limited to loans similar in collateral, term and structure and loan purpose or type. We evaluate loan pools based on aggregated risk ratings, estimated specific loss potential in the different classes of credits, and historical loss experience by pool type. We adjust these quantitative factors for qualitative factors of present conditions. Qualitative factors include items such as economic and business conditions, changes in the portfolio, value of underlying collateral, and concentrations. Residential mortgage loan pools exclude loans that have been restructured or impaired, as those loans are evaluated individually.
A rollforward of our valuation allowance and ending balances of the allowance and loan balance by basis of impairment method was as follows:
	Commercial			Residential			Total
	(in millions)
For the year ended December 31, 2013
Beginning balance	$	51.8		$	45.6		$	97.4
Provision		4.1			10.8			14.9
Charge-offs		(28.0	)		(18.3	)		(46.3	)
Recoveries		0.8			3.1			3.9
Effect of exchange rates		—			(0.1	)		(0.1	)
Ending balance	$	28.7		$	41.1		$	69.8
Allowance ending balance by basis of impairment method:
Individually evaluated for impairment	$	2.4		$	10.2		$	12.6
Collectively evaluated for impairment		26.3			30.9			57.2
Allowance ending balance	$	28.7		$	41.1		$	69.8
Loan balance by basis of impairment method:
Individually evaluated for impairment	$	4.4		$	33		$	37.4
Collectively evaluated for impairment		10,323.30			1,242.70			11,566.00
Loan ending balance	$	10,327.70		$	1,275.70		$	11,603.40
For the year ended December 31, 2012
Beginning balance	$	64.8		$	37.3		$	102.1
Provision		13.5			39.7			53.2
Charge-offs		(26.7	)		(35.1	)		(61.8	)
Recoveries		0.2			3.6			3.8
Effect of exchange rates		—			0.1			0.1
Ending balance	$	51.8		$	45.6		$	97.4
Allowance ending balance by basis of impairment method:
Individually evaluated for impairment	$	2.4		$	10.4		$	12.8
Collectively evaluated for impairment		49.4			35.2			84.6
Allowance ending balance	$	51.8		$	45.6		$	97.4
Loan balance by basis of impairment method:
Individually evaluated for impairment	$	13.6		$	39.7		$	53.3
Collectively evaluated for impairment		10,221.50			1,342.30			11,563.80
Loan ending balance	$	10,235.10		$	1,382.00		$	11,617.10
For the year ended December 31, 2011
Beginning balance	$	80.6		$	40.5		$	121.1
Provision		17			27.2			44.2
Charge-offs		(32.9	)		(33.4	)		(66.3	)
Recoveries		0.1			3.2			3.3
Effect of exchange rates		—			(0.2	)		(0.2	)
Ending balance	$	64.8		$	37.3		$	102.1
Allowance ending balance by basis of impairment method:
Individually evaluated for impairment	$	16.3		$	3.2		$	19.5
Collectively evaluated for impairment		48.5			34.1			82.6
Allowance ending balance	$	64.8		$	37.3		$	102.1
Loan balance by basis of impairment method:
Individually evaluated for impairment	$	114		$	27.4		$	141.4
Collectively evaluated for impairment		9,347.40			1,340.50			10,687.90
Loan ending balance	$	9,461.40		$	1,367.90		$	10,829.30
Impaired Mortgage Loans
Impaired mortgage loans are loans with a related specific valuation allowance, loans whose carrying amount has been reduced to the expected collectible amount because the impairment has been considered other than temporary or a loan modification has been classified as a TDR. Based on an assessment as to the collectability of the principal, a determination is made to apply any payments received either against the principal or according to the contractual terms of the loan. Our recorded investment in and unpaid principal balance of impaired loans along with the related loan specific allowance for losses, if any, and the average recorded investment and interest income recognized during the time the loans were impaired were as follows:
	December 31, 2013
	Recorded			Unpaid			Related
	investment			principal			allowance
				balance
	(in millions)
With no related allowance recorded:
Commercial-brick and mortar	$	21.5		$	32.7		$	—
Residential-first liens		4.6			4.6			—
With an allowance recorded:
Commercial-brick and mortar		4.4			4.4			2.4
Residential-home equity		19.5			19.7			9.2
Residential-first liens		8.9			7.8			1
Total:
Commercial	$	25.9		$	37.1		$	2.4
Residential	$	33		$	32.1		$	10.2
	December 31, 2012
	Recorded			Unpaid			Related
	investment			principal			allowance
				balance
	(in millions)
With no related allowance recorded:
Commercial-brick and mortar	$	22.9		$	25.3		$	—
Residential-first liens		9.7			6.6			—
With an allowance recorded:
Commercial-brick and mortar		4.4			4.4			2.4
Residential-home equity		20.8			20.7			9.1
Residential-first liens		9.2			9.1			1.3
Total:
Commercial	$	27.3		$	29.7		$	2.4
Residential	$	39.7		$	36.4		$	10.4
	Average			Interest income
	recorded			recognized
	investment
	(in millions)
For the year ended December 31, 2013
With no related allowance recorded:
Commercial-brick and mortar	$	22.2		$	0.2
Residential-first liens		7.2			—
With an allowance recorded:
Commercial-brick and mortar		4.4			0.3
Residential-home equity		20.2			1.1
Residential-first liens		8.9			0.2
Total:
Commercial	$	26.6		$	0.5
Residential	$	36.3		$	1.3
For the year ended December 31, 2012
With no related allowance recorded:
Commercial-brick and mortar	$	11.4		$	2.6
Residential-first liens		7			—
With an allowance recorded:
Commercial-brick and mortar		59.2			0.2
Residential-home equity		17.7			0.9
Residential-first liens		9			0.1
Total:
Commercial	$	70.6		$	2.8
Residential	$	33.7		$	1
For the year ended December 31, 2011
With no related allowance recorded:
Commercial-brick and mortar	$	11.3		$	0.9
Residential-first liens		4.4			—
With an allowance recorded:
Commercial-brick and mortar		79			1
Residential-home equity		12.6			0.8
Residential-first liens		9.6			0.2
Total:
Commercial	$	90.3		$	1.9
Residential	$	26.6		$	1
Mortgage Loan Modifications
Our commercial and residential mortgage loan portfolios include loans that have been modified. We assess loan modifications on a case-by-case basis to evaluate whether a TDR has occurred. The commercial mortgage loan TDRs were modified to delay or reduce principal payments and to increase, reduce or delay interest payments. For these TDR assessments, we have determined the loan rates are now considered below market based on current circumstances. The commercial mortgage loan modifications resulted in delayed cash receipts and a decrease in interest income. The residential mortgage loan TDRs include modifications of interest-only payment periods, delays in principal balloon payments, and interest rate reductions. Residential mortgage loan modifications resulted in delayed or decreased cash receipts and a decrease in interest income.
The following table includes information about outstanding loans that were modified and met the criteria of a TDR during the periods indicated. In addition, the table includes information for loans that were modified and met the criteria of a TDR within the past twelve months that were in payment default during the periods indicated:
	For the year ended December 31, 2013
	TDRs						TDRs in payment default
	Number of			Recorded			Number of			Recorded
	contracts			investment			contracts			investment
				(in millions)						(in millions)
Commercial-brick and mortar		2		$	0.9			—		$	—
Residential-home equity		69			3.8			19			—
Residential-first liens		3			0.6			1			0.3
Total		74		$	5.3			20		$	0.3
	For the year ended December 31, 2012
	TDRs						TDRs in payment default
	Number of			Recorded			Number of			Recorded
	contracts			investment			contracts			investment
				(in millions)						(in millions)
Commercial-brick and mortar		2		$	18			1		$	13.7
Residential-home equity		324			15			12			—
Residential-first liens		12			2.1			—			—
Total		338		$	35.1			13		$	13.7
	For the year ended December 31, 2011
	TDRs						TDRs in payment default
	Number of			Recorded			Number of			Recorded
	contracts			investment			contracts			investment
				(in millions)						(in millions)
Commercial-brick and mortar		1		$	4.4			1		$	4.4
Residential-home equity		151			7.9			6			—
Residential-first liens		7			1.6			1			0.3
Total		159		$	13.9			8		$	4.7
Commercial mortgage loans that have been designated as a TDR have been previously reserved in the mortgage loan valuation allowance to the estimated fair value of the underlying collateral reduced by the cost to sell.
Residential mortgage loans that have been designated as a TDR are specifically reserved for in the mortgage loan valuation allowance if losses result from the modification. Residential mortgage loans that have defaulted or have been discharged through bankruptcy are reduced to the expected collectible amount.
Real Estate
Depreciation expense on invested real estate was $44.4 million, $45.1 million and $41.4 million in 2013, 2012 and 2011, respectively. Accumulated depreciation was $364.9 million and $332.8 million as of December 31, 2013 and 2012, respectively.
Other Investments
Other investments include minority interests in unconsolidated entities, domestic and international joint ventures and partnerships and properties owned jointly with venture partners and operated by the partners. Such investments are generally accounted for using the equity method. In applying the equity method, we record our share of income or loss reported by the equity investees in net investment income. Summarized financial information for these unconsolidated entities was as follows:
	December 31,
	2013			2012
	(in millions)
Total assets	$	47,401.90		$	46,036.20
Total liabilities		39,588.00			38,080.90
Total equity	$	7,813.90		$	7,955.30
Net investment in unconsolidated entities (1)	$	1,098.60		$	1,100.60
	For the year ended
	December 31,
	2013			2012			2011
	(in millions)
Total revenues	$	3,002.90		$	4,555.90		$	5,574.60
Total expenses		2,253.20			3,774.50			4,849.80
Net income		738.6			750.1			719.3
Our share of net income of unconsolidated entities (1)		133.4			120.1			116.5
-1
Primarily relates to Brasilprev Seguros e Previdencia, a co-managed joint venture in Brazil, which is reported in the results of our Principal International segment.
In addition, other investments include $720.2 million and $655.1 million of direct financing leases as of December 31, 2013 and 2012, respectively. 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. The direct financing lease receivables are carried at amortized cost. We actively monitor and manage our direct financing leases. All leases within the portfolio are analyzed regularly and internally rated, based on financial condition, payment history and loan-to-value.
Derivative assets are carried at fair value and reported as a component of other investments. Certain seed money investments are also carried at fair value and reported as a component of other investments, with changes in fair value included in net realized capital gains (losses) on our consolidated statements of operations.
Securities Posted as Collateral
We posted $1,057.4 million in fixed maturities, available-for-sale securities at December 31, 2013, to satisfy collateral requirements primarily associated with a reinsurance arrangement, our derivative credit support annex (collateral) agreements, Futures Commission Merchant ("FCM") agreements and our obligation under funding agreements with the Federal Home Loan Bank of Des Moines ("FHLB Des Moines"). In addition, we posted $2,435.4 million in commercial mortgage loans and home equity mortgages as of December 31, 2013, to satisfy collateral requirements associated with our obligation under funding agreements with the FHLB Des Moines. Since we did not relinquish ownership rights on these instruments, they are reported as fixed maturities, available-for-sale and mortgage loans, respectively, on our consolidated statements of financial position.
Balance Sheet Offsetting
We have financial instruments that are subject to master netting agreements or similar agreements. Financial assets subject to master netting agreements or similar agreements were as follows:
				Gross amounts not offset in
				the Statement of Financial
				Position
	Gross amount			Financial			Collateral			Net amount
	of recognized			instruments (2)			received
	assets (1)
	(in millions)
December 31, 2013
Derivative assets	$	664.9		$	(581.5	)	$	(82.1	)	$	1.3
Reverse repurchase agreements		51.8			—			(51.8	)		—
Total	$	716.7		$	(581.5	)	$	(133.9	)	$	1.3
December 31, 2012
Derivative assets	$	1,016.30		$	(779.3	)	$	(225.5	)	$	11.5
Reverse repurchase agreements		148.2			—			(148.2	)		—
Total	$	1,164.50		$	(779.3	)	$	(373.7	)	$	11.5
-1
The gross amount of recognized derivative and reverse repurchase agreement assets are reported with other investments on the consolidated statements of financial position. The above excludes $0.2 million and $0.4 million of derivative assets as of December 31, 2013 and December 31, 2012, 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 master netting agreements or similar agreements were as follows:
				Gross amounts not offset in
				the Statement of Financial
				Position
	Gross amount			Financial			Collateral			Net amount
	of recognized			instruments (2)			pledged
	liabilities (1)
	(in millions)
December 31, 2013
Derivative liabilities	$	1,022.00		$	(581.5	)	$	(362.1	)	$	78.4
December 31, 2012
Derivative liabilities	$	1,198.20		$	(779.3	)	$	(279.1	)	$	139.8
-1
The gross amount of recognized derivative liabilities are reported with other liabilities and contractholder funds on the consolidated statements of financial position. The above excludes $226.7 million and $329.8 million of derivative liabilities as of December 31, 2013 and December 31, 2012, respectively, which are primarily embedded derivatives that are not subject to master netting agreements or similar agreements. The gross amount of recognized repurchase agreement liabilities are reported with short-term debt on the consolidated statements of financial position. The gross amounts of derivative and repurchase agreement 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.
The financial instruments that are subject to master netting agreements or similar agreements include right of setoff provisions. Derivative instruments include provisions to setoff positions covered under the agreements with the same counterparties and provisions to setoff positions outside of the agreements with the same counterparties in the event of default by one of the parties. Derivative instruments also include collateral provisions. Collateral received and pledged is generally settled daily with each counterparty. See Note 6, Derivative Financial Instruments, for further details.
Repurchase and reverse repurchase agreements include provisions to setoff other repurchase and reverse repurchase balances with the same counterparty. Repurchase and reverse repurchase agreements also include collateral provisions with the counterparties. For reverse repurchase agreements we require the counterparties to pledge collateral with a value greater than the amount of cash transferred. We have the right but do not sell or repledge collateral received in reverse repurchase agreements. Repurchase agreements are structured as secured borrowings for all counterparties. We pledge fixed maturities available-for-sale, which the counterparties have the right to sell or repledge. Interest incurred on repurchase agreements is reported as part of operating expense on the consolidated statements of operations. Net proceeds related to repurchase agreements are reported as a component of financing activities on the consolidated statements of cash flows. We did not have any outstanding repurchase agreements as of December 31, 2013 and December 31, 2012.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2013
Derivative Financial Instruments	'
Derivative Financial Instruments	'
	6. 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 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 collars to manage interest rate risk related to guaranteed minimum interest rate liabilities in our individual annuities contracts and lapse risk associated with higher interest rates.
	A swaption is an option to enter into an interest rate swap at a future date. We purchase swaptions to offset or modify existing exposures. Swaptions provide us the benefit of the agreed-upon strike rate if the market rates for liabilities are higher, with the flexibility to enter into the current market rate swap if the market rates for liabilities are lower. 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.
	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 we issue, foreign currency-denominated fixed maturities we invest in and the financial results of our international operations, including 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 and to hedge the currency risk associated with a business combination. We have also used currency forwards to hedge the currency risk associated with net investments in foreign operations. We did not use any currency forwards during 2013 or 2012 to hedge our net investment in foreign operations.
	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 manage the foreign currency risk associated with a business combination.
	Equity Contracts
	Equity risk is the risk that we will incur economic losses due to adverse fluctuations in common stock. We use various derivatives to manage our exposure to equity risk, which arises from products in which the interest we credit is tied to an external equity index as well as products subject to minimum contractual guarantees.
	We previously sold an investment-type insurance contract with attributes tied to market indices (an embedded derivative as noted below), in which case we wrote an equity call option to convert the overall contract into a fixed-rate liability, essentially eliminating the equity component altogether. We purchase equity call spreads 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, as previously explained. The premium associated with certain options is paid quarterly over the life of the option contract.
	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.
	Total return swaps are contracts in which we agree with other parties to exchange, at specified intervals, an amount determined by the difference between the previous price and the current price of a reference asset based upon an agreed upon notional principal amount plus an additional amount determined by the financing spread. We currently use futures traded on an exchange ("exchange-traded") and total return swaps referencing equity indices to hedge our portfolio from potential credit losses related to systemic events.
	Other Contracts
	Embedded Derivatives.    We purchase or issue certain financial instruments or products that contain a derivative instrument that is embedded in the financial instrument or product. When it is determined that the embedded derivative possesses economic characteristics that are not clearly or closely related to the economic characteristics of the host contract and a separate instrument with the same terms would qualify as a derivative instrument, the embedded derivative is bifurcated from the host instrument for measurement purposes. The embedded derivative, which is reported with the host instrument in the consolidated statements of financial position, is carried at fair value.
	We sell investment-type insurance contracts in which the return is tied to a leveraged inflation index. In addition, we previously sold an investment-type insurance contract in which the return was tied to an external equity index. We economically hedge the risk associated with these investment-type insurance contracts.
	We offer group benefit plan 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 have structured investment relationships with trusts we have determined to be VIEs, which are consolidated in our financial statements. The notes issued by these trusts include obligations to deliver an underlying security to residual interest holders and the obligations contain an embedded derivative of the forecasted transaction to deliver the underlying security.
	We have fixed deferred annuities and universal life contracts 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 reduced to zero. 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 recognized 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.
	We posted $393.1 million and $296.9 million in cash and securities under collateral arrangements as of December 31, 2013 and December 31, 2012, respectively, to satisfy collateral requirements associated with our derivative credit support agreements and FCM agreements. Beginning in the second quarter 2013, these amounts include initial margin requirements.
	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, 2013 and December 31, 2012, was $1,042.9 million and $1,205.4 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 $393.1 million and $296.9 million as of December 31, 2013 and December 31, 2012, 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, 2013, we would be required to post an additional $75.9 million of collateral to our counterparties.
	As of December 31, 2013 and December 31, 2012, we had received $32.5 million and $207.8 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, 2013			December 31, 2012
		(in millions)
	Notional amounts of derivative instruments
	Interest rate contracts:
	Interest rate swaps	$	20,570.80		$	18,381.20
	Interest rate options		4,100.00			500
	Swaptions		325			325
	Interest rate futures		92.5			82
	Foreign exchange contracts:
	Currency swaps		2,367.50			3,454.10
	Currency forwards		247.4			557.2
	Currency options		—			1,400.00
	Equity contracts:
	Equity options		2,010.40			1,811.80
	Equity futures		273.3			373.6
	Credit contracts:
	Credit default swaps		1,153.20			1,378.30
	Total return swaps		90			100
	Futures		9.1			—
	Other contracts:
	Embedded derivative financial instruments		7,601.10			5,893.20
	Total notional amounts at end of period	$	38,840.30		$	34,256.40
	Credit exposure of derivative instruments
	Interest rate contracts:
	Interest rate swaps	$	435.5		$	683.9
	Interest rate options		42.5			48.5
	Swaptions		1			0.7
	Foreign exchange contracts:
	Currency swaps		200.9			263.8
	Currency forwards		0.6			6.8
Currency options		—			1.9
Equity contracts:
Equity options		30			74.3
Credit contracts:
Credit default swaps		9.5			6.8
Total return swaps		0.1			—
Total gross credit exposure		720.1			1,086.70
Less: collateral received		115.9			248
Net credit exposure	$	604.2		$	838.7
The fair value of our derivative instruments classified as assets and liabilities was as follows:
	Derivative assets (1)						Derivative liabilities (2)
	December 31, 2013			December 31, 2012			December 31, 2013			December 31, 2012
	(in millions)
Derivatives designated as hedging instruments
Interest rate contracts	$	0.1		$	10.3		$	285.4		$	440.5
Foreign exchange contracts		121.6			190			51.2			127.2
Total derivatives designated as hedging instruments	$	121.7		$	200.3		$	336.6		$	567.7
Derivatives not designated as hedging instruments
Interest rate contracts	$	452.2		$	677.1		$	489.6		$	493.9
Foreign exchange contracts		51.6			58.2			17.9			14.3
Equity contracts		30			74.3			145			27.7
Credit contracts		9.6			6.8			35.5			96.6
Other contracts		—			—			224.1			327.8
Total derivatives not designated as hedging instruments		543.4			816.4			912.1			960.3
Total derivative instruments	$	665.1		$	1,016.70		$	1,248.70		$	1,528.00
-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 derivative liabilities with a fair value of $6.9 million and $170.5 million as of December 31, 2013 and December 31, 2012, 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. The majority of our credit derivative contracts sold reference a single name or reference security (referred to as "single name credit default swaps"). The remainder of our credit derivatives reference either a basket or index of securities. These instruments are either referenced in an over-the-counter 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 have purchased credit protection with identical underlyings to certain of our sold protection transactions. The effect of this purchased protection would reduce our total maximum future payments by $44.9 million as of December 31, 2013 and $15.0 million as of December 31, 2012. These purchased credit derivative transactions had a net asset (liability) fair value of $(0.5) million as of December 31, 2013 and $0.2 million as of December 31, 2012. In certain circumstances, our potential loss could also be reduced by any amount recovered in the default proceedings of the underlying credit name.
We purchased an investment structure with embedded credit features that is fully consolidated into our financial statements. This consolidation results in recognition of the underlying credit derivatives and collateral within the structure, typically high quality fixed maturities that are owned by a special purpose vehicle. These credit derivatives reference several names in a basket structure. In the event of default, the collateral within the structure would typically be liquidated to pay the claims of the credit derivative counterparty.
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, 2013
	Notional			Fair			Maximum			Weighted
	amount			value			future			average
							payments			expected life
										(in years)
	(in millions)
Single name credit default swaps
Corporate debt
AAA	$	10		$	0.3		$	10			4.7
AA		84			1.8			84			4
A		294.5			4.2			294.5			4
BBB		265			(1.2	)		265			3.9
Total single name credit default swaps		653.5			5.1			653.5			4
Basket and index credit default swaps
Corporate debt
Near default (1)		110.4			(19.9	)		110.4			3.2
Government/municipalities
AA		30			(3.5	)		30			3.7
Structured finance
BBB		25			(0.9	)		25			3.5
Total basket and index credit default swaps		165.4			(24.3	)		165.4			3.4
Total credit default swap protection sold	$	818.9		$	(19.2	)	$	818.9			3.9
	December 31, 2012
	Notional			Fair			Maximum			Weighted
	amount			value			future			average
							payments			expected life
										(in years)
	(in millions)
Single name credit default swaps
Corporate debt
AA	$	70		$	(0.2	)	$	70			2.5
A		572			2.4			572			2.4
BBB		200			(1.6	)		200			3
Structured finance
Near default		11.1			(11.0	)		11.1			8.5
Total single name credit default swaps		853.1			(10.4	)		853.1			2.6
Basket and index credit default swaps
Corporate debt
Near default (1)		110.4			(65.2	)		110.4			4.2
Government/municipalities
AA		30			(7.3	)		30			4.7
Structured finance
BBB		25			(5.6	)		25			4.5
Total basket and index credit default swaps		165.4			(78.1	)		165.4			4.4
Total credit default swap protection sold	$	1,018.50		$	(88.5	)	$	1,018.50			2.9
-1
Includes $88.0 million notional of derivatives in consolidated collateralized private investment vehicle VIEs where the credit risk is borne by third-party investors.
We also have invested in fixed maturities classified as available-for-sale that contain credit default swaps that do not require bifurcation and fixed maturities classified as trading that contain credit default swaps. These securities are subject to the credit risk of the issuer, normally a special purpose vehicle, which consists of the underlying credit default swaps and high quality fixed maturities that serve as collateral. A default event occurs if the cumulative losses exceed a specified attachment point, which is typically not the first loss of the portfolio. If a default event occurs that exceeds the specified attachment point, our investment may not be fully returned. We would have no future potential payments under these investments. The following tables show, by the types of referenced/underlying asset class and external rating, our fixed maturities with embedded credit derivatives.
	December 31, 2013
	Amortized			Carrying			Weighted
	cost			value			average
							expected life
							(in years)
	(in millions)
Corporate debt
BBB	$	23.4		$	23.4			3
Total corporate debt		23.4			23.4			3
Structured finance
A		18.1			16.7			4.8
BB		5.5			5.5			3.3
B		4.1			4.1			3.1
CCC		23.5			23.5			4.8
Total structured finance		51.2			49.8			4.5
Total fixed maturities with credit derivatives	$	74.6		$	73.2			4
	December 31, 2012
	Amortized			Carrying			Weighted
	cost			value			average
							expected life
							(in years)
	(in millions)
Corporate debt
BBB	$	20.5		$	20.5			4
B		25			24.9			0.5
Total corporate debt		45.5			45.4			2.1
Structured finance
AA		4.6			4.6			17
BB		39.6			37.5			2.9
B		4			4			4.4
CCC		17.7			17.7			6.4
Total structured finance		65.9			63.8			4.9
Total fixed maturities with credit derivatives	$	111.4		$	109.2			3.8
Fair Value Hedges
We use fixed-to-floating rate interest rate swaps to more closely align the interest rate characteristics of certain assets and 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.
We enter into currency exchange swap agreements to convert certain foreign denominated assets and liabilities into U.S. dollar floating-rate denominated instruments to eliminate the exposure to future currency volatility on those items.
We have sold callable investment-type insurance contracts and used cancellable interest rate swaps to hedge the changes in fair value of the callable feature.
The net interest effect of interest rate swap and currency 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.
Hedge effectiveness testing for fair value relationships is performed utilizing a regression analysis approach for both prospective and retrospective evaluations. This regression analysis will consider multiple data points for the assessment that the hedge continues to be highly effective in achieving offsetting changes in fair value. In certain periods, the comparison of the change in value of the derivative and the change in the value of the hedged item may not be offsetting at a specific period in time due to small movements in value. However, any amounts recorded as fair value hedges have shown to be highly effective in achieving offsetting changes in fair value both for present and future periods.
The following table shows the effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations. All gains or losses on derivatives were included in the assessment of hedge effectiveness.
	Amount of gain (loss)											Amount of gain (loss)
	recognized in net income											recognized in net income
	on derivatives											on related hedged item
	for the year ended											for the year ended
Derivatives in fair value	December 31, (1)									Hedged items in fair fair value		December 31, (1)
hedging relationships	2013			2012			2011			hedging relationships		2013			2012			2011
	(in millions)											(in millions)
Interest rate contracts	$	139.5		$	38.6		$	(108.5	)	Fixed maturities, available-for-sale		$	(133.3	)	$	(34.1	)	$	105.4
Interest rate contracts		(0.7	)		—			(2.2	)	Investment-type insurance contracts			0.2			—			2.4
Foreign exchange contracts		(0.2	)		0.7			1.1		Fixed maturities, available-for-sale			0.4			0.4			(1.3	)
Foreign exchange contracts		(36.7	)		9.3			(25.6	)	Investment-type insurance contracts			36.5			(12.6	)		25.7
Total	$	101.9		$	48.6		$	(135.2	)	Total		$	(96.2	)	$	(46.3	)	$	132.2
-1
The gain (loss) on both derivatives and hedged items in fair value relationships is reported in net realized capital gains (losses) on the consolidated statements of operations. The net amount represents the ineffective portion of our fair value hedges.
The following table shows the periodic settlements on interest rate contracts and foreign exchange contracts in fair value hedging relationships.
	Amount of gain (loss)
	for the year ended
	December 31,
Hedged Item	2013			2012			2011
	(in millions)
Fixed maturities, available-for-sale (1)	$	(120.7	)	$	(134.3	)	$	(158.9	)
Investment-type insurance contracts (2)		33.2			37.1			44
-1
Reported in net investment income on the consolidated statements of operations.
-2
Reported in benefits, claims and settlement expenses on the consolidated statements of operations.
Cash Flow Hedges
We utilize 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 maximum length of time we are hedging our exposure to the variability in future cash flows for forecasted transactions, excluding those related to the payments of variable interest on existing financial assets and liabilities, is 6.5 years. At December 31, 2013, we had $61.7 million of net gains reported in AOCI on the consolidated statements of financial position related to active hedges of forecasted transactions. If a hedged forecasted transaction is no longer probable of occurring, cash flow hedge accounting is discontinued. If it is probable that the hedged forecasted transaction will not occur, the deferred gain or loss is immediately reclassified from OCI into net income. We reclassified $0.2 million and $0.0 million from AOCI into net realized capital gains (losses) as a result of the determination that hedged cash flows were probable of not occurring during the twelve months ended December 31, 2013 and 2012, respectively.
The following table shows the effect of derivatives in cash flow hedging relationships on the consolidated statements of operations and consolidated statements of financial position. All gains or losses on derivatives were included in the assessment of hedge effectiveness.
			Amount of gain											Amount of gain
			(loss) recognized											(loss) reclassified
			in AOCI on											from AOCI on
			derivatives (effective											derivatives (effective
			portion) for the year									Location of gain (loss)		portion) for the year
			ended December 31,									reclassified from AOCI		ended December 31,
Derivatives in cash flow												into net income
hedging relationships	Related hedged item		2013			2012			2011			(effective portion)		2013			2012			2011
			(in millions)											(in millions)
Interest rate contracts	Fixed maturities, available-for-sale		$	(80.5	)	$	16.2		$	107.1		Net investment income		$	11.7		$	8.9		$	7.2
												Net realized capital losses			—			—			(0.2	)
Interest rate contracts	Investment-type insurance contracts			2.5			2.5			(1.0	)	Benefits, claims and settlement expenses			—			—			(0.8	)
Interest rate contracts	Debt			—			—			—		Operating expense			(6.6	)		(5.9	)		(5.3	)
Foreign exchange contracts	Fixed maturities, available-for-sale			(0.9	)		(27.9	)		29.9		Net realized capital losses			(16.7	)		(6.4	)		(20.4	)
Foreign exchange contracts	Investment-type insurance contract			5			7.6			12.8		Benefits, claims and settlement expenses			—			—			(1.7	)
Total			$	(73.9	)	$	(1.6	)	$	148.8		Total		$	(11.6	)	$	(3.4	)	$	(21.2	)
The following table shows the periodic settlements on interest rate contracts and foreign exchange contracts in cash flow hedging relationships.
	Amount of gain (loss)
	for the year ended
	December 31,
Hedged Item	2013			2012			2011
	(in millions)
Fixed maturities, available-for-sale (1)	$	7.7		$	8		$	9.3
Investment-type insurance contracts (2)		(11.0	)		(13.4	)		(13.1	)
-1
Reported in net investment income on the consolidated statements of operations.
-2
Reported in benefits, claims and settlement expenses on the consolidated statements of operations.
The ineffective portion of our cash flow hedges is reported in net realized capital gains (losses) on the consolidated statements of operations. The net gain resulting from the ineffective portion of foreign currency contracts in cash flow hedging relationships was $0.8 million, $0.5 million and $0.5 million for the years ended December 31, 2013, 2012 and 2011, respectively.
We expect to reclassify net gains of $2.8 million from AOCI into net income in the next 12 months, which includes both net deferred gains on discontinued hedges and net losses on periodic settlements of active hedges. Actual amounts may vary from this amount as a result of market conditions.
Derivatives Not Designated as Hedging Instruments
Our use of futures, certain swaptions and swaps, 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. Gains and losses on certain derivatives used in relation to certain trading portfolios are reported in net investment income 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	2013			2012			2011
	(in millions)
Interest rate contracts	$	(137.6	)	$	(7.9	)	$	93.3
Foreign exchange contracts		(0.1	)		63.1			(34.1	)
Equity contracts		(159.4	)		(100.5	)		55.2
Credit contracts		40.6			11			(9.9	)
Other contracts		154.4			37.3			(200.4	)
Total	$	(102.1	)	$	3		$	(95.9	)

Closed_Block

Closed Block	12 Months Ended
	Dec. 31, 2013
Closed Block	'
Closed Block	'
	7. 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, including, but 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 their 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 earnings in the Closed Block that are not available to stockholders. A model of the Closed Block was established to produce the pattern of expected earnings in the Closed Block, adjusted to eliminate the impact of related amounts in AOCI.
	If actual cumulative earnings of the Closed Block are greater than the expected cumulative earnings of the Closed Block, only the expected cumulative earnings will be recognized in income with the excess recorded as a PDO. This PDO represents undistributed accumulated earnings that will be paid to Closed Block policyholders as additional policyholder dividends unless offset by future performance of the Closed Block that is less favorable than originally expected. If actual cumulative performance is less favorable than expected, only actual earnings will be recognized in income. At December 31, 2013 and 2012, cumulative actual earnings have been less than cumulative expected earnings. However, cumulative net unrealized gains were greater than expected, resulting in the recognition of a PDO of $111.6 million and $131.0 million as of December 31, 2013 and 2012, respectively.
	Closed Block liabilities and assets designated to the Closed Block were as follows:
		December 31, 2013			December 31, 2012
		(in millions)
	Closed Block liabilities
	Future policy benefits and claims	$	4,532.00		$	4,664.50
	Other policyholder funds		10.5			10.7
	Policyholder dividends payable		270.5			280.6
	Policyholder dividends obligation		111.6			131
	Deferred income taxes		2.2			—
	Other liabilities		24.7			31.3
	Total Closed Block liabilities		4,951.50			5,118.10
	Assets designated to the Closed Block
	Fixed maturities, available-for-sale		2,470.90			2,735.10
	Fixed maturities, trading		13.4			17
	Equity securities, available-for-sale		3.6			5.5
	Mortgage loans		828.6			719.4
	Policy loans		644.2			665.5
	Other investments		118.5			158
	Total investments		4,079.20			4,300.50
	Cash and cash equivalents		70.3			51.3
	Accrued investment income		49.5			52.5
	Premiums due and other receivables		11.7			13.2
	Deferred tax asset		66.2			39.2
	Other assets		2.2			—
	Total assets designated to the Closed Block		4,279.10			4,456.70
	Excess of Closed Block liabilities over assets designated to the Closed Block		672.4			661.4
	Amounts included in accumulated other comprehensive income		12.9			62.4
	Maximum future earnings to be recognized from Closed Block assets and liabilities	$	685.3		$	723.8
	Closed Block revenues and expenses were as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Revenues
	Premiums and other considerations	$	379.9		$	397.4		$	428.8
	Net investment income		207.7			222.8			238.2
	Net realized capital gains (losses)		(12.3	)		3.6			7.9
	Total revenues		575.3			623.8			674.9
	Expenses
	Benefits, claims and settlement expenses		320.1			325.7			370.7
	Dividends to policyholders		184.4			192.6			204.2
	Operating expenses		4.7			4.9			2.9
	Total expenses		509.2			523.2			577.8
	Closed Block revenues, net of Closed Block expenses, before income taxes		66.1			100.6			97.1
	Income taxes		21.1			32.6			31.2
	Closed Block revenues, net of Closed Block expenses and income taxes		45			68			65.9
	Funding adjustment charges		(6.5	)		(4.8	)		(5.3	)
	Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustment charges	$	38.5		$	63.2		$	60.6
	The change in maximum future earnings of the Closed Block was as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Beginning of year	$	723.8		$	787		$	847.6
	End of year		685.3			723.8			787
	Change in maximum future earnings	$	(38.5	)	$	(63.2	)	$	(60.6	)
	Principal Life charges the Closed Block with 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, 2013
Deferred Acquisition Costs	'
Deferred Acquisition Costs	'
	8. Deferred Acquisition Costs
	Acquisition costs deferred and amortized were as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Balance at beginning of year	$	2,590.00		$	2,358.10		$	2,442.20
	Cost deferred during the year		447			428.9			344.4
	Amortized to expense during the year (1)		(187.1	)		(94.9	)		(271.4	)
	Adjustment related to unrealized gains on available-for-sale securities and derivative instruments		227.1			(102.1	)		(157.1	)
	Balance at end of year	$	3,077.00		$	2,590.00		$	2,358.10
	-1
	Includes adjustments for revisions to estimated gross profits.

Insurance_Liabilities

Insurance Liabilities	12 Months Ended
	Dec. 31, 2013
Insurance Liabilities	'
Insurance Liabilities	'
	9. Insurance Liabilities
	Contractholder Funds
	Major components of contractholder funds in the consolidated statements of financial position are summarized as follows:
		December 31,
		2013		2012
		(in millions)
	Liabilities for investment-type insurance contracts:
	Liabilities for individual annuities	$	10,582.70	$	11,316.20
	GICs		10,858.30		10,943.10
	Funding agreements		7,642.90		9,077.10
	Other investment-type insurance contracts		832.6		787.2
	Total liabilities for investment-type insurance contracts		29,916.50		32,123.60
	Universal life and other reserves		6,041.80		5,662.90
	Total contractholder funds	$	35,958.30	$	37,786.50
	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, as well as under 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, 2013 and 2012, $370.9 million and $1,189.5 million, respectively, of liabilities are 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 vehicle. As of December 31, 2013 and 2012, $1,278.7 million and $1,251.1 million, respectively, of liabilities are 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, 2013 and 2012, $637.6 million and $1,598.5 million, respectively, of liabilities are 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 $4.0 billion of funding agreements under a program established in March 2004 to support the prospective issuance of medium term notes by unaffiliated entities in both domestic and international markets. In February 2006, this program was amended to authorize issuance of up to an additional $5.0 billion in recognition of the use of nearly all $4.0 billion of initial issuance authorization. In recognition of the use of nearly all $9.0 billion, this program was amended in November 2007 to authorize issuance of up to an additional $5.0 billion. Under this program, both the notes and the supporting funding agreements were registered with the SEC. As of December 31, 2013 and 2012, $975.0 million and $1,875.6 million, respectively, of liabilities are 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 are 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 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. As of December 31, 2013 and 2012, $2,630.5 million and $1,352.3 million of liabilities are being held with respect to any issuances outstanding under this program. Similar to the SEC-registered 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.
	Future Policy Benefits and Claims
	Activity associated with unpaid disability and health claims is summarized as follows:
		December 31,
		2013		2012		2011
		(in millions)
	Balance at beginning of year	$	1,066.00	$	1,006.90	$	1,061.80
	Incurred:
	Current year		712		711.8		1,074.00
	Prior years		1		9.7		(10.8	)
	Total incurred		713		721.5		1,063.20
	Payments:
	Current year		432.1		446.3		820.8
	Prior years		202.2		216.1		297.3
	Total payments		634.3		662.4		1,118.10
	Balance at end of year:
	Current year		279.9		265.5		253.2
	Prior years		864.8		800.5		753.7
	Total balance at end of year	$	1,144.70	$	1,066.00	$	1,006.90
	Amounts not included in the rollforward above:
	Claim adjustment expense liabilities	$	43.4	$	46.6	$	42.9
	Reinsurance recoverables for unpaid claims		260.1		239.1		204.7
	Incurred liability adjustments relating to prior years, which affected current operations during 2013, 2012 and 2011, resulted in part from developed claims for prior years being different than were anticipated when the liabilities for unpaid disability and health claims were originally estimated. These trends have been considered in establishing the current year liability for unpaid disability and health claims.

Debt

Debt	12 Months Ended
	Dec. 31, 2013
Debt	'
Debt	'
	10. Debt
	Short-Term Debt
	The components of short-term debt were as follows:
		December 31,
		2013		2012
		(in millions)
	Line of credit	$	117.8	$	—
	Other recourse short-term debt		32.8		40.8
	Total short-term debt	$	150.6	$	40.8
	As of December 31, 2013 and 2012, we had short-term credit facilities with various financial institutions in an aggregate amount of $1,105.0 million and $905.0 million, respectively. As of December 31, 2013 and 2012, we had $150.6 million and $40.8 million, respectively, of outstanding borrowings, with no assets pledged as support. Our credit facilities include a $500.0 million 4-year facility that matures in March 2016, with Principal Financial Services, Inc., Principal Life and us as co-borrowers and a $300.0 million 364-day facility for Principal Life only which was refinanced in April 2013. Also in April 2013, we added a $200.0 million 3-year facility with Principal Financial Services, Inc., Principal Life Insurance Company, Principal Financial Services V (UK) LTD and us as the borrowers. These facilities may be used for general corporate purposes, including commercial paper back-stop. Our commercial paper programs require 100% back-stop support, of which there were no outstanding balances as of December 31, 2013 and 2012.
	The weighted-average interest rate on short-term borrowings as of both December 31, 2013 and 2012, was 4.7%.
	Long-Term Debt
	The components of long-term debt were as follows:
		December 31,
		2013		2012
		(in millions)
	3.76% notes payable, due 2015	$	—	$	92.7
	1.85% notes payable, due 2017		299.8		299.7
	8.875% notes payable, due 2019		350		350
	3.3% notes payable, due 2022		299		298.9
	3.125% notes payable, due 2023		299.6		299.6
	6.05% notes payable, due 2036		601.6		601.7
	4.625% notes payable, due 2042		299.5		299.5
	4.35% notes payable, due 2043		299.3		299.2
	8.0% surplus notes payable, due 2044		99.3		99.3
	Non-recourse mortgages and notes payable		53.3		30.7
	Total long-term debt	$	2,601.40	$	2,671.30
	The amounts included above are net of the discount and premium associated with issuing these notes, which are being amortized to expense over their respective terms using the interest method.
	On November 16, 2012, we issued $900.0 million of senior notes. We issued a $300.0 million series of notes that bear interest at 1.85% and will mature in 2017, 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 AFP Cuprum S.A.
	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 AFP Cuprum S.A. We incurred a one-time cost to extinguish this debt before the scheduled maturity date.
	On November 3, 2010, Principal International de Chile S.A., a wholly owned indirect subsidiary, entered into a long-term borrowing agreement with Banco de Chile in the amount of US $98.9 million. The debt was denominated in Unidades de Formento ("UF"), a Chilean inflation-indexed, peso-denominated monetary unit, bore interest at UF +3.76% and had a maturity date of November 3, 2015. On May 3, 2013, Principal International de Chile S.A., prepaid these notes without penalty as authorized under the borrowing agreement with Banco de Chile at par value upon the semi — annual interest payment date.
	On May 18, 2009, we issued $750.0 million of senior notes. We issued a $400.0 million series of notes that bear interest at 7.875% and were to mature on May 15, 2014, and a $350.0 million series of notes that bear interest at 8.875% and will mature on May 15, 2019. Interest on the notes is 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 and October 15 each year and began on April 15, 2007. The notes will mature on October 15, 2036. A portion of the proceeds were used to fund the 2006 acquisition of WM Advisors, Inc., with the remaining proceeds being used for general corporate purposes.
	On March 10, 1994, Principal Life issued $100.0 million of surplus notes due March 1, 2044, at an 8% annual interest rate. None of our affiliates hold any portion of the notes. Each payment of interest and principal on the notes, however, may be made only with the prior approval of the Commissioner of Insurance of the State of Iowa (the "Commissioner") and only to the extent that Principal Life has sufficient surplus earnings to make such payments. Interest of $8.0 million for each of the years ended December 31, 2013, 2012 and 2011 was approved by the Commissioner, and charged to expense.
	Subject to Commissioner approval, the notes due March 1, 2044, may be redeemed at Principal Life's election on or after March 1, 2014, in whole or in part at a redemption price of approximately 102.3% of par. The approximate 2.3% premium is scheduled to gradually diminish over the following ten years. These notes may be redeemed on or after March 1, 2024, at a redemption price of 100% of the principal amount plus interest accrued to the date of redemption. On January 21, 2014, the Commissioner approved Principal Life's election to redeem the surplus notes. On January 30, 2014, Principal Life provided surplus note holders with a notice of redemption and will redeem the $100.0 million surplus notes in whole on March 1, 2014, at a redemption price equal to 102.3% of par.
	The non-recourse mortgages, other mortgages and notes payable are primarily financings for real estate developments. Outstanding principal balances as of December 31, 2013, ranged from $1.6 million to $20.1 million per development with interest rates being 5.5% or variable. Outstanding principal balances as of December 31, 2012, ranged from $0.3 million to $9.2 million per development with interest rates generally ranging from 5.5% to 5.8%. 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 $101.4 million and $54.2 million as of December 31, 2013 and 2012, respectively.
	Also included in non-recourse mortgages and notes payable is a long-term debt obligation we assumed with the purchase of WM Advisors, Inc. As part of the purchase, we are bound by a class B share financing agreement previously entered into by WM Advisors, Inc. and a third party. Load mutual fund shares sold without a front end load are referred to as "B shares". In exchange for paying the selling commission, we receive fees in the future to recover the up-front commission cost incurred. Prior to our purchase, WM Advisors, Inc. had entered into a purchase and sale agreement whereby the third party would purchase the rights to future cash flow streams in exchange for funding the sales commissions. The fair value of these relinquished fees is reported as a long-term debt liability. There will be no additional sales under this agreement following the effective date of the purchase. Therefore, this liability will be extinguished in 2014, which equates to the remaining contractual term in which the fund can recover fees to cover the upfront commission costs. The value of this obligation as of December 31, 2013 and 2012, was $0.2 million and $1.2 million, respectively.
	At December 31, 2013, future annual maturities of the long-term debt were as follows (in millions):
	Year ending December 31:
	2014	$	0.3
	2015		5.3
	2016		—
	2017		299.8
	2018		—
	Thereafter		2,296.00
	Total future maturities of the long-term debt	$	2,601.40

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Taxes	'
Income Taxes	'
	11. Income Taxes
	Income Tax Expense
	Our income tax expense was as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Current income taxes (benefits):
	U.S. federal	$	109.5		$	(66.9	)	$	115.4
	State		7.7			(4.7	)		7.2
	Foreign		69.7			48.7			44.4
	Tax benefit of operating loss carryforward		(134.1	)		(73.7	)		(0.2	)
	Total current income taxes (benefits)		52.8			(96.6	)		166.8
	U.S. federal		155.1			221.3			43.9
	State		(3.1	)		(1.7	)		(2.6	)
	Foreign		(16.9	)		11.6			(9.8	)
	Total deferred income taxes		135.1			231.2			31.5
	Total income taxes	$	187.9		$	134.6		$	198.3
	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,
		2013			2012			2011
	U.S. corporate income tax rate		35	%		35	%		35	%
	Dividends received deduction		(10	)		(10	)		(9	)
	Impact of equity method presentation		(3	)		(4	)		(4	)
	Interest exclusion from taxable income		(2	)		(2	)		(3	)
	Foreign tax rate differential		(2	)		(2	)		—
	Impact of court ruling on some uncertain tax positions		—			—			7
	Other		(1	)		(3	)		(3	)
	Effective income tax rate		17	%		14	%		23	%
	Unrecognized Tax Benefits
	A summary of the changes in unrecognized tax benefits follows.
		For the year
		ended
		December 31,
		2013			2012
		(in millions)
	Balance at beginning of period	$	119.5		$	114.3
	Additions based on tax positions related to the current year		10.5			10.5
	Additions for tax positions of prior years		10.9			4.4
	Reductions for tax positions related to the current year		(3.3	)		(4.2	)
	Reductions for tax positions of prior years		(28.7	)		(5.5	)
	Balance at end of period (1)	$	108.9		$	119.5
	-1
	Of this amount, $55.4 million, if recognized, would reduce the 2013 effective income tax rate. We recognize interest and penalties related to uncertain tax positions in operating expenses.
	As of December 31, 2013 and 2012, we had recognized $37.0 million and $44.1 million of accumulated pre-tax interest and penalties related to unrecognized tax benefits, respectively.
	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. We reclassified certain components of deferred income taxes for the year ended December 31, 2012, to conform with December 31, 2013, presentation. The reclassification resulted in an increase in gross deferred income tax assets of $138.9 million and a corresponding increase in gross deferred tax liabilities of $138.9 million. The reclassification had no impact on the amount of valuation allowance established by us and, as a result, the net deferred tax liability remains unchanged. Significant components of our net deferred income taxes were as follows:
		December 31,
		2013			2012
		(in millions)
	Deferred income tax assets:
	Insurance liabilities	$	241.1		$	544
	Investments, including derivatives		464.2			530.5
	Net operating and capital loss carryforwards		339.8			386.2
	Employee benefits		320.6			491.9
	Other deferred income tax assets		90.4			55.9
	Gross deferred income tax assets		1,456.10			2,008.50
	Valuation allowance		(0.7	)		(2.7	)
	Total deferred income tax assets		1,455.40			2,005.80
	Deferred income tax liabilities:
	Deferred acquisition costs		(807.2	)		(635.3	)
Investments, including derivatives		(418.3	)		(562.7	)
Net unrealized gains on available-for-sale securities		(584.5	)		(1,114.9	)
Real estate		(117.3	)		(102.0	)
Intangible assets		(297.7	)		(160.0	)
Other deferred income tax liabilities		(4.8	)		(10.1	)
Total deferred income tax liabilities		(2,229.8	)		(2,585.0	)
Total net deferred income tax liabilities	$	(774.4	)	$	(579.2	)
Net deferred income taxes by jurisdiction were as follows:
	December 31,
	2013			2012
	(in millions)
Deferred income tax assets:
State	$	—		$	3.9
Foreign		49.6			16.9
Net deferred income tax assets		49.6			20.8
Deferred income tax liabilities:
U.S. Federal		(503.4	)		(446.2	)
State		(1.5	)		—
Foreign		(319.1	)		(153.8	)
Net deferred income tax liabilities		(824.0	)		(600.0	)
Total net deferred income tax liabilities	$	(774.4	)	$	(579.2	)
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 net operating loss and tax credit carryforwards for tax purposes available to offset future taxable income. We have net operating loss and tax credit carryforwards for U.S. federal income tax purposes of $670.8 million and $988.1 million at December 31, 2013 and 2012, respectively, primarily attributable to our captive reinsurance companies that joined our consolidated U.S. federal income tax return in 2012 and 2013. These U.S. federal net operating loss and tax credit carryforwards will expire between 2021 and 2034. All accumulated U.S. federal net operating loss and tax credit carryforwards are anticipated to be utilized before expiration; therefore, no valuation allowance has been provided for the related deferred income tax assets.
Domestic state net operating loss carryforwards were $397.7 million and $328.6 million as of December 31, 2013 and 2012, respectively, and will expire between 2015 and 2033. Foreign net operating loss carryforwards generated in various foreign countries were $95.7 million and $70.6 million as of December 31, 2013 and 2012, respectively, with some net operating loss carryforwards expiring in 2014 while others never expire. We maintain valuation allowances by jurisdiction against the deferred income tax assets related to certain of these carryforwards, as utilization of these income tax benefits fail the more likely than not criteria in certain jurisdictions. As of December 31, 2013 and 2012, valuation allowances of $0.7 million and $2.3 million, respectively, have been recorded on income tax benefits associated 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.
U.S. federal and state deferred income taxes have not been provided on approximately $693.7 million and $551.1 million of accumulated but undistributed earnings from operations of foreign subsidiaries at December 31, 2013 and 2012, respectively. These earnings are considered to be indefinitely reinvested in the business. It is not practicable to determine the amount of the unrecognized deferred tax liability that would arise if these earnings were remitted due to foreign tax credits and exclusions that may become available at the time of remittance. At December 31, 2013, 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 of our foreign subsidiaries. A tax liability will be recognized when we no longer plan to indefinitely reinvest these earnings or when we plan to sell all or a portion of our ownership interest.
Other Tax Information
Income tax returns are filed in the 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 Internal Revenue Service ("IRS") has completed examination of our consolidated U.S. federal income tax returns for years prior to 2004. We are contesting certain issues and have filed suit in the Court of Federal Claims, requesting refunds for the years 1995-2003. We do not expect litigation to be resolved within the next twelve months. We had $329.9 million and $334.6 million of current income tax receivables associated with outstanding audit issues reported as other assets in our consolidated statements of financial position as of December 31, 2013 and 2012, respectively.
The IRS completed its examinations of tax years 2004 through 2008. We filed claims for refund for tax years 2004 and 2005 during 2012 and will file claims for refund relating to disputed adjustments for tax years 2006 through 2008 in 2014. The IRS commenced audit of our U.S. federal income tax return for 2009 during the fourth quarter of 2011, for 2010 during the first quarter of 2012 and for 2011 during the first quarter of 2013. We do not expect the results of these audits 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 do not believe there is a reasonable possibility the total amount of unrecognized tax benefits will significantly increase or decrease in the next twelve months. The range disclosed in our 2012 financial statements was prior to the January 2013 expiration of the right to appeal the U.S. District Court for the Southern District of Iowa decision in the case of Pritired 1, LLC. We believe that we have adequate defenses against, or sufficient provisions for, the contested issues, but final resolution of the contested issues could take several years while legal remedies are pursued. Consequently, we do not expect the ultimate resolution of issues from tax years 1995-2003 to have a material impact on our net income. Similarly, we believe there are adequate defenses against, or sufficient provisions for, any challenges that might arise in tax years subsequent to 2003.

Employee_and_Agent_Benefits

Employee and Agent Benefits	12 Months Ended
	Dec. 31, 2013
Employee and Agent Benefits	'
Employee and Agent Benefits	'
	12. Employee and Agent Benefits
	We have defined benefit pension plans covering substantially all of our U.S. employees and certain agents. Some of these plans provide supplemental pension benefits to employees and agents with salaries and/or pension benefits in excess of the qualified plan limits imposed by federal tax law. The employees and agents are generally first eligible for the pension plans when they reach age 21. For plan participants employed prior to January 1, 2002, the pension benefits are based on the greater of a final average pay benefit or a cash balance benefit. 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 of employment. Partial benefit accrual of final average pay benefits is recognized from first eligibility until retirement based on attained service divided by potential service to age 65 with a minimum of 35 years of potential service. The cash balance portion of the plan started on January 1, 2002. An employee's account is credited with an amount based on the employee's salary, age and service. These credits accrue with interest. For plan participants hired on and after January 1, 2002, only the cash balance plan applies. Our policy is to fund the cost of providing pension benefits in the years that the employees and agents are providing service to us. Our funding policy for the qualified defined benefit plan is to contribute an amount annually at least equal to 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 federal income tax purposes. Our funding policy for the nonqualified benefit plan is to fund the plan in the years that the employees are providing service, taking into account the funded status of the trust. 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 also provide certain health care, life insurance and long-term care benefits for retired employees. Subsidized retiree health benefits are provided for employees hired prior to January 1, 2002. Employees hired after December 31, 2001, have access to retiree health benefits but it is intended that they pay for the full cost of the coverage. The health care plans are contributory with participants' contributions adjusted annually. The contributions are based on the number of years of service and age at retirement for those hired prior to January 1, 2002, who retired prior to January 1, 2011. For employees hired prior to January 1, 2002, who retired on or after January 1, 2011, the contributions are 60% of the expected cost. As part of the substantive plan, the retiree health contributions are assumed to be adjusted in the future as claim levels change. The life insurance plans are contributory for a small group of previously grandfathered participants that have elected supplemental coverage and dependent coverage.
	Covered employees are first eligible for the health and life postretirement benefits when they reach age 57 and have completed ten years of service with us. Retiree long-term care benefits are provided for employees whose retirement was effective prior to July 1, 2000. Our policy is to fund the cost of providing retiree benefits in the years that the employees are providing service, taking into account the funded status of the trust.
	Obligations and Funded Status
	The plans' combined funded status, reconciled to amounts recognized in the consolidated statements of financial position and consolidated statements of operations, was as follows:
		Pension benefits						Other
								postretirement
								benefits
		December 31,						December 31,
		2013			2012			2013			2012
		(in millions)
	Change in benefit obligation
	Benefit obligation at beginning of year	$	(2,638.0	)	$	(2,158.4	)	$	(147.8	)	$	(165.1	)
	Service cost		(57.1	)		(47.0	)		(1.0	)		(1.3	)
	Interest cost		(103.8	)		(109.1	)		(5.7	)		(8.2	)
	Actuarial gain (loss)		279.2			(407.1	)		7.9			21.2
	Participant contribution		—			—			(6.8	)		(6.6	)
	Benefits paid		79.5			76.4			13.6			13
	Other		—			7.2			(0.8	)		(0.8	)
	Benefit obligation at end of year	$	(2,440.2	)	$	(2,638.0	)	$	(140.6	)	$	(147.8	)
	Change in plan assets
	Fair value of plan assets at beginning of year	$	1,682.10		$	1,429.00		$	519.7		$	466.6
	Actual return on plan assets		199.8			222.6			95.9			58.6
	Employer contribution		123.2			106.9			4.2			0.9
	Participant contributions		—			—			6.8			6.6
	Benefits paid		(79.5	)		(76.4	)		(13.6	)		(13.0	)
	Fair value of plan assets at end of year	$	1,925.60		$	1,682.10		$	613		$	519.7
	Amount recognized in statement of financial position
	Other assets	$	—		$	—		$	473		$	372.5
	Other liabilities		(514.6	)		(955.9	)		(0.6	)		(0.6	)
	Total	$	(514.6	)	$	(955.9	)	$	472.4		$	371.9
	Amount recognized in accumulated other comprehensive (income) loss
	Total net actuarial (gain) loss	$	391.1		$	861.2		$	(83.1	)	$	(7.1	)
	Prior service benefit		(11.8	)		(20.4	)		(56.2	)		(82.1	)
	Pre-tax accumulated other comprehensive (income) loss	$	379.3		$	840.8		$	(139.3	)	$	(89.2	)
	The accumulated benefit obligation for all defined benefit pension plans was $2,287.4 million and $2,469.1 million at December 31, 2013 and 2012, 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 $304.3 million and $300.8 million as of December 31, 2013 and 2012, respectively.
	Pension Plan Changes and Plan Gains/Losses
	On January 1, 2010, benefits under the Principal Pension Plan were frozen for certain participants.
	For the year ended December 31, 2013, the pension plans had a gain primarily due to an increase in the discount rate. For the year ended December 31, 2012, the pension plans had a loss primarily due to a decrease in the discount rate, partially offset by higher than expected asset returns.
	Other Postretirement Plan Changes and Plan Gains/Losses
	On December 8, 2003, the Medicare Prescription Drug, Improvement and Modernization Act of 2003 (the "Medicare Modernization Act") was signed into law. The Medicare Modernization Act introduced a prescription drug benefit under Medicare ("Medicare Part D") as well as a federal subsidy to sponsors of retiree medical benefit plans. During each of the years ended December 31, 2013, 2012 and 2011, the Medicare subsidies we received and accrued for were $0.8 million, $0.8 million and $0.9 million, respectively.
	An actuarial gain occurred during 2013 for the other postretirement benefit plans. This was due to an increase in the discount rate and trend assumption for post-65 retirees and a change in assumptions for retirees who voluntarily drop medical coverage at age 65 or older. An actuarial gain occurred during 2012 for the other postretirement benefit plans. This was due to a decrease in the trend and claim cost assumptions. This was partially offset by the decrease in the discount rate.
	Impact from Exit of Group Medical Insurance Business
	On September 30, 2010, we announced our decision to exit the group medical insurance business and entered into an agreement with United Healthcare Services, Inc. to renew medical insurance coverage for our customers as the business transitions. Our exit from the group medical insurance business resulted in a curtailment gain associated with the pension and other postretirement benefits of the impacted employees, which was recognized in our consolidated financial statements as impacted employees were terminated. For the year ended December 31, 2011, the curtailment gain recognized was $1.4 million for the pension benefits and $5.1 million for the other postretirement benefits, respectively, from the accelerated recognition of the existing prior service benefits. One final recognition of the curtailment in 2012 resulted in a curtailment gain of $0.7 million for the pension plan and $3.5 million for the other postretirement benefits.
	Information for Pension Plans With an Accumulated Benefit Obligation in Excess of Plan Assets
	For 2013 and 2012, 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,
		2013			2012
		(in millions)
	Projected benefit obligation	$	2,440.20		$	2,638.00
	Accumulated benefit obligation		2,287.40			2,469.10
	Fair value of plan assets		1,925.60			1,682.10
	Information for Other Postretirement Benefit Plans With an Accumulated Postretirement Benefit Obligation in Excess of Plan Assets
		December 31,
		2013			2012
		(in millions)
	Accumulated postretirement benefit obligation	$	1.5		$	1.7
	Fair value of plan assets		0.9			1.1
	Components of Net Periodic Benefit Cost
		Pension benefits									Other postretirement
											benefits
	For the year ended December 31,
	2013			2012			2011			2013			2012			2011
	(in millions)
Service cost	$	57.1		$	47		$	44		$	1		$	1.3		$	1.2
Interest cost		103.8			109.1			108.5			5.7			8.2			8.9
Expected return on plan assets		(127.4	)		(114.6	)		(114.4	)		(28.8	)		(33.5	)		(34.1	)
Amortization of prior service benefit		(8.7	)		(9.4	)		(9.7	)		(25.9	)		(28.6	)		(29.3	)
Recognized net actuarial loss		118.5			90.9			65.8			1			0.9			0.4
Amounts recognized due to special events		—			(0.7	)		(1.4	)		—			(3.5	)		(5.1	)
Net periodic benefit cost (income)	$	143.3		$	122.3		$	92.8		$	(47.0	)	$	(55.2	)	$	(58.0	)
The pension plans' actuarial gains and losses are amortized using a straight-line amortization method over the average remaining service period of plan participants. 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
	benefits						postretirement
							benefits
	For the year ended December 31,
	2013			2012			2013			2012
	(in millions)
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	$	(351.7	)	$	292.1		$	(75.0	)	$	(46.4	)
Amortization of net loss		(118.5	)		(90.9	)		(1.0	)		(0.9	)
Amortization of prior service benefit		8.7			10.1			25.9			32.1
Total recognized in pre-tax accumulated other comprehensive (income) loss	$	(461.5	)	$	211.3		$	(50.1	)	$	(15.2	)
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	$	(318.2	)	$	333.6		$	(97.1	)	$	(70.4	)
Net actuarial (gain) loss and net prior service cost benefit have been recognized in AOCI.
The estimated net actuarial (gain) loss and prior service cost (benefit) that will be amortized from AOCI into net periodic benefit cost for the pension benefits during the 2014 fiscal year are $50.6 million and $(4.8) million, respectively. The estimated net actuarial (gain) loss and prior service cost (benefit) for the postretirement benefits that will be amortized from AOCI into net periodic benefit cost during the 2014 fiscal year are $(3.4) million and $(20.3) million, respectively.
Assumptions
Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section
	Pension						Other
	benefits						postretirement
							benefits
	For the year ended December 31,
	2013			2012			2013			2012
Discount rate		4.9	%		4	%		4.9	%		4	%
Rate of compensation increase		4.8	%		4.8	%		4.83	%		4.83	%
Weighted average assumptions used to determine net periodic benefit cost
	Pension benefits									Other
										postretirement
										benefits
	For the year ended December 31,
	2013			2012			2011			2013			2012			2011
Discount rate		4	%		5.15	%		5.65	%		4	%		5.15	%		5.65	%
Expected long-term return on plan assets		7.5	%		8	%		8	%		5.62	%		7.3	%		7.3	%
Rate of compensation increase		4.8	%		5	%		5	%		4.83	%		5	%		5	%
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 plans' investment strategy. Historical and expected future returns of multiple asset classes were analyzed to develop a risk free rate of return and risk premiums for each asset class. The overall rate for each asset class was developed by combining a long-term inflation component, the risk free real rate of return and the associated risk premium. A weighted average rate was developed based on those overall rates and the target asset allocation of the plans.
For other postretirement benefits, the 5.62% expected long-term return on plan assets for 2013 is based on the weighted average expected long-term asset returns for the medical, life and long-term care plans. The expected long-term rates for the medical, life and long-term care plans are 5.4%, 7.75% and 5.85%, respectively.
Assumed Health Care Cost Trend Rates
	December 31,
	2013			2012
Health care cost trend rate assumed for next year under age 65		8	%		8	%
Health care cost trend rate assumed for next year age 65 and over		6	%		7	%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		4.5	%		4.5	%
Year that the rate reaches the ultimate trend rate (under age 65)		2020			2019
Year that the rate reaches the ultimate trend rate (65 and older)		2019			2017
Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plans. A one-percentage-point change in assumed health care cost trend rates would have the following effects:
	1-percentage			1-percentage
	point increase			point decrease
	(in millions)
Effect on total of service cost and interest cost components	$	0.3		$	(0.3	)
Effect on accumulated postretirement benefit obligation		(6.1	)		5.3
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. Our Level 1 assets include cash, fixed income investment funds and exchange traded equity securities.
•
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. Our Level 2 assets primarily include fixed income and equity investment funds and real estate investments.
•
Level 3 — Fair values are based on significant unobservable inputs for the asset. Our Level 3 assets include a Principal Life general account investment.
Our pension plan assets consist of investments in separate accounts. Net asset value ("NAV") of the 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 separate accounts invest in publicly quoted mutual funds or actively managed stocks. The fair value of the underlying mutual funds or stock is used to determine the NAV of the separate account, which is not publicly quoted. Some of the 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.
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. The fair value of the Principal Life general account investment is the amount the plan would receive if withdrawing funds from this participating contract. The amount that would be received is calculated using a cash-out factor based on an associated pool of general account fixed income securities. The cash-out factor is a ratio of the asset investment value of these securities to asset book value. As the investment values change, the cash-out factor is adjusted, impacting the amount the plan receives at measurement date. To determine investment value for each category of assets, we project cash flows. This is done using contractual provisions for the assets, with adjustment for expected prepayments and call provisions. Projected cash flows are discounted to present value for each asset category. Interest rates for discounting are based on current rates on similar new assets in the general account based on asset strategy.
Pension Plan Assets
The fair value of the qualified pension plan's assets by asset category as of the most recent measurement date is as follows:
	As of December 31, 2013
				Fair value hierarchy level
	Assets
	measured at
	fair value			Level 1			Level 2			Level 3
	(in millions)
Asset category
U.S. large cap equity portfolios (1)	$	414		$	—		$	414		$	—
U.S. small/mid cap equity portfolios (2)		102.9			—			102.9			—
Balanced asset portfolios (3)		96.9			—			96.9			—
International equity portfolios (4)		171			—			171			—
Fixed income security portfolios (5)		1,048.50			—			1,048.50			—
Real estate investment portfolios:
Direct real estate investments (6)		92.3			—			92.3			—
Total	$	1,925.60		$	—		$	1,925.60		$	—
	As of December 31, 2012
				Fair value hierarchy level
	Assets
	measured at
	fair value			Level 1			Level 2			Level 3
	(in millions)
Asset category
U.S. large cap equity portfolios (1)	$	601.8		$	—		$	601.8		$	—
U.S. small/mid cap equity portfolios (2)		156.2			—			156.2			—
Balanced asset portfolios (3)		82.4			—			82.4			—
International equity portfolios (4)		273.9			—			273.9			—
Fixed income security portfolios (5)		486.6			—			486.6			—
Real estate investment portfolios:
Direct real estate investments (6)		81.2			—			81.2			—
Total	$	1,682.10		$	—		$	1,682.10		$	—
-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 portfolios invest in various fixed income securities, primarily of U.S. origin. These include, but are not limited to, corporate bonds, mortgage-backed securities, commercial mortgage-backed securities, U.S. Treasury securities, agency securities, asset-backed securities and collateralized mortgage obligations.
-6
The portfolio invests primarily in U.S. commercial real estate properties.
The reconciliation for all assets measured at fair value using significant unobservable inputs (Level 3) for 2011 was as follows. We had no Level 3 assets in 2012 and 2013.
	For the year ended December 31, 2011
				Actual return gains (losses) on plan assets
																			Ending
																			asset
																			balance
																			as of
																			December 31,
	Beginning			Relating to			Relating to			Net			Transfers			Transfers			2011
	asset			assets still			assets sold			purchases,			into			out of
	balance as			held at the			during the			sales and			Level 3			Level 3
	of December 31,			reporting			period			settlements
	2010			date
	(in millions)
Asset category
Direct real estate investments	$	84.7		$	1.6		$	—		$	1		$	—		$	(87.3	)	$	—
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
U.S. equity portfolios	0% - 45%
International equity portfolios	0% - 15%
Fixed income security portfolios	30% - 100%
Real estate investment portfolios	0% - 10%
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 is as follows:
	As of December 31, 2013
				Fair value hierarchy level
	Assets
	measured at
	fair value			Level 1			Level 2			Level 3
	(in millions)
Asset category
Cash and cash equivalents	$	4.7		$	4.7		$	—		$	—
Fixed income security portfolios:
Fixed income investment funds (1)		157.9			157.9			—			—
Principal Life general account investment (2)		38.8			—			—			38.8
U.S. equity portfolios (3)		351.6			288			63.6			—
International equity portfolios (4)		60			45.9			14.1			—
Total	$	613		$	496.5		$	77.7		$	38.8
	As of December 31, 2012
				Fair value hierarchy level
	Assets
	measured at
	fair value			Level 1			Level 2			Level 3
	(in millions)
Asset category
Cash and cash equivalents	$	1.9		$	1.9		$	—		$	—
Fixed income security portfolios:
Fixed income investment funds (1)		163.5			163.5			—			—
Principal Life general account investment (2)		42.1			—			—			42.1
U.S. equity portfolios (3)		260.8			213.5			47.3			—
International equity portfolios (4)		51.4			39.3			12.1			—
Total	$	519.7		$	418.2		$	59.4		$	42.1
-1
The portfolios invest in various fixed income securities, primarily of U.S. origin. These include, but are not limited to, corporate bonds, mortgage-backed securities, commercial mortgage-backed securities, U.S. Treasury securities, agency securities, asset-backed securities and collateralized mortgage obligations.
-2
The general account is invested in various fixed income securities.
-3
The portfolios invest primarily in publicly traded equity securities of large U.S. companies.
-4
The portfolios invest primarily in publicly traded equity securities of non-U.S. companies.
As of December 31, 2013 and 2012, respectively, $77.7 million and $59.4 million of assets in the U.S. equity and international equity portfolios were included in a trust owned life insurance contract.
The reconciliation for all assets measured at fair value using significant unobservable inputs (Level 3) is as follows:
	For the year ended December 31, 2013
				Actual return gains
				(losses) on plan assets															Ending
																			asset
																			balance
																			as of
																			December 31,
	Beginning			Relating to			Relating to			Net			Transfers			Transfers			2013
	asset			assets still			assets sold			purchases,			into			out of
	balance as			held at the			during the			sales, and			Level 3			Level 3
	of December 31,			reporting			period			settlements
	2012			date
	(in millions)
Asset category
Principal Life general account investment	$	42.1		$	1.1		$	—		$	(4.4	)	$	—		$	—		$	38.8
	For the year ended December 31, 2012
				Actual return gains (losses) on plan assets
																			Ending
																			assets
																			balance
																			as of
	Beginning									Net									December 31,
	assets									purchases,									2012
	balance as									sales,
	of December 31,									and
	2011			Relating to			Relating to			settlements			Transfers			Transfers
				assets still			assets sold						into			out of
				held at the			during the						Level 3			Level 3
				reporting date			period
	(in millions)
Asset category
Principal Life general account investment	$	42.5		$	3.1		$	—		$	(3.5	)	$	—		$	—		$	42.1
	For the year ended December 31, 2011
				Actual return gains
				(losses) on plan assets															Ending
																			assets
																			balance
																			as of
	Beginning																		December 31,
	assets																		2011
	balance as
	of December 31,
	2010			Relating to			Relating to			Net			Transfers			Transfers
				assets still			assets sold			purchases,			into			out of
				held at the			during the			sales, and			Level 3			Level 3
				reporting date			period			settlements
	(in millions)
Asset category
Principal Life general account investment	$	44.5		$	3		$	—		$	(5.0	)	$	—		$	—		$	42.5
According to our investment policy, the target asset allocation for the other postretirement benefit plans is:
Asset Category	Target allocation
U.S. equity portfolios	45% - 65%
International equity portfolios	5% - 15%
Fixed income security portfolios	30% - 50%
The investment strategies and policies for the other postretirement benefit plans are similar to those employed by the qualified pension plan.
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 federal income tax purposes. We do not anticipate contributions will be needed to satisfy the minimum funding requirements of ERISA for our qualified plan. At this time, it is too early to estimate the amount that may be contributed, but it is possible that we may fund the plans in 2014 in the range of $125-$175 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 2014 pending future analysis.
Estimated Future Benefit Payments
The estimated future benefit payments, which reflect expected future service, and the expected amount of subsidy receipts under Medicare Part D are:
	Pension benefits			Other postretirement			Amount of Medicare
				benefits (gross benefit			Part D subsidy receipts
				payments, including
				prescription drug benefits)
	(in millions)
Year ending December 31:
2014	$	98.7		$	18.1		$	1
2015		102.9			18.6			1
2016		108.2			19			1
2017		114.4			19.3			1.1
2018		120.6			19.4			1.1
2019 - 2023		708.4			99.1			5.1
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, 2013.
The information that follows shows supplemental information for our defined benefit pension plans. Certain key summary data is shown separately for qualified and nonqualified plans.
	For the year ended December 31,
	2013									2012
	Qualified			Nonqualified			Total			Qualified			Nonqualified			Total
	Plan			Plan						Plan			Plan
	(in millions)
Amount recognized in statement of financial position
Other assets	$	—		$	—		$	—		$	—		$	—		$	—
Other liabilities		(138.6	)		(376.0	)		(514.6	)		(557.7	)		(398.2	)		(955.9	)
Total	$	(138.6	)	$	(376.0	)	$	(514.6	)	$	(557.7	)	$	(398.2	)	$	(955.9	)
Amount recognized in accumulated other comprehensive loss
Total net actuarial loss	$	298.3		$	92.8		$	391.1		$	725		$	136.2		$	861.2
Prior service benefit		(6.5	)		(5.3	)		(11.8	)		(12.5	)		(7.9	)		(20.4	)
Pre-tax accumulated other comprehensive loss	$	291.8		$	87.5		$	379.3		$	712.5		$	128.3		$	840.8
Components of net periodic benefit cost
Service cost	$	50.4		$	6.7		$	57.1		$	42.3		$	4.7		$	47
Interest cost		88.2			15.6			103.8			92.8			16.3			109.1
Expected return on plan assets		(127.4	)		—			(127.4	)		(114.6	)		—			(114.6	)
Amortization of prior service benefit		(6.1	)		(2.6	)		(8.7	)		(6.3	)		(3.1	)		(9.4	)
Recognized net actuarial loss		104.4			14.1			118.5			84.8			6.1			90.9
Amounts recognized due to special events		—			—			—			(0.4	)		(0.3	)		(0.7	)
Net periodic benefit cost	$	109.5		$	33.8		$	143.3		$	98.6		$	23.7		$	122.3
Other changes recognized in accumulated other comprehensive (income) loss
Net actuarial (gain) loss	$	(322.4	)	$	(29.3	)	$	(351.7	)	$	223.5		$	68.6		$	292.1
Amortization of net loss		(104.4	)		(14.1	)		(118.5	)		(84.8	)		(6.1	)		(90.9	)
Amortization of prior service benefit		6.1			2.6			8.7			6.7			3.4			10.1
Total recognized in pre-tax accumulated other comprehensive (income) loss	$	(420.7	)	$	(40.8	)	$	(461.5	)	$	145.4		$	65.9		$	211.3
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	$	(311.2	)	$	(7.0	)	$	(318.2	)	$	244		$	89.6		$	333.6
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 $17,500 of their compensation to the plans in 2013. 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. The employees who elected to retain the prior benefit provisions are referred to as "Grandfathered Choice Participants." We match the Grandfathered Choice Participant's contribution at a 50% contribution rate up to a maximum contribution of 3% of the participant's compensation. For all other participants, we match the participant's contributions at a 75% contribution rate up to a maximum of 6% of the participant's compensation. The defined contribution plans allow employees to choose among various investment options, including our common stock. We contributed $39.8 million, $37.3 million and $36.3 million in 2013, 2012 and 2011, respectively, to our qualified defined contribution plans.
We also have nonqualified deferred compensation plans available to select employees and agents that allow them to defer compensation amounts in excess of limits imposed by federal tax law with respect to the qualified plans. In 2013, we matched the Grandfathered Choice Participant's deferral at a 50% match deferral rate up to a maximum matching deferral of 3% of the participant's compensation. For all other participants, we matched the participant's deferral at a 75% match deferral rate up to a maximum matching deferral of 6% of the participant's compensation. We contributed $5.0 million, $4.6 million and $3.5 million in 2013, 2012 and 2011, respectively, to our nonqualified deferred compensation plans.

Contingencies_Guarantees_and_I

Contingencies, Guarantees and Indemnifications	12 Months Ended
	Dec. 31, 2013
Contingencies, Guarantees and Indemnifications	'
Contingencies, Guarantees and Indemnifications	'
	13. Contingencies, Guarantees and Indemnifications
	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, the Department of Labor, the Federal Reserve Board and other regulatory agencies 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 8, 2006, a trustee of Fairmount Park Inc. Retirement Savings Plan filed a putative class action lawsuit in the United States District Court for the Southern District of Illinois against Principal Life. The complaint alleged, among other things, that Principal Life breached its alleged fiduciary duties while performing services to 401(k) plans by failing to disclose, or adequately disclose, to employers or plan participants the fact that Principal Life receives "revenue sharing fees from mutual funds that are included in its pre-packaged 401(k) plans" and allegedly failed to use the revenue to defray the expenses of the services provided to the plans. Plaintiff sought to certify a class of all retirement plans to which Principal Life was a service provider and for which Principal Life received and retained "revenue sharing" fees from mutual funds. On June 13, 2011, the court entered a consent judgment resolving the claims of the plaintiff. On July 12, 2011, plaintiff filed a notice of appeal related to the issue of the denial of class certification. On February 13, 2013, the Eighth Circuit Court of Appeals dismissed the appeal. Plaintiff filed a petition for a writ of certiorari with the U.S. Supreme Court, which was denied on October 7, 2013.
	On August 29, 2013, American Chemicals & Equipment, Inc. 401(k) Retirement Plan ("ACE") filed a lawsuit in the United States District Court for the Northern District of Alabama against Principal Management Corporation and Principal Global Investors, LLC (the "ACE Defendants"). The lawsuit alleges the ACE Defendants breached their fiduciary duty under Section 36(b) of the Investment Company Act by charging excessive fees on certain of the LifeTime series target date funds. On January 24, 2014, the court granted the motion filed by the ACE Defendants to transfer the case to the Southern District of Iowa. The ACE Defendants are aggressively defending the lawsuit.
	On December 2, 2009 and December 4, 2009, two plaintiffs, Cruise and Mullaney, each filed putative class action lawsuits in the United States District Court for the Southern District of New York against us; Principal Life; Principal Global Investors, LLC; Principal Management Corporation; and Principal Real Estate Investors, LLC (the "Cruise/Mullaney Defendants"). The lawsuits alleged the Cruise/Mullaney Defendants failed to manage the Principal U.S. Property Separate Account ("PUSPSA") in the best interests of investors, improperly imposed a "withdrawal freeze" on September 26, 2008, and instituted a "withdrawal queue" to honor withdrawal requests as sufficient liquidity became available. The two lawsuits, as well as two subsequently filed complaints asserting similar claims, have been consolidated and are now known as In re Principal U.S. Property Account Litigation. Plaintiffs' request for permission to appeal the denial of class certification was denied by the U.S. Eighth Circuit Court of Appeals on December 31, 2013. The Cruise/Mullaney Defendants are aggressively defending the lawsuit.
	In 2008, Principal Life received approximately $440.0 million in connection with the termination of certain structured transactions and the resulting prepayment of Principal Life's investment in those transactions. The transactions involved Lehman Brothers Special Financing Inc. and Lehman Brothers Holdings Inc. (collectively, "Lehman") in various capacities. Subsequent to Lehman's 2008 bankruptcy filing, its bankruptcy estate initiated several law suits seeking to recover from numerous sources significant amounts to which it claims entitlement under various theories. The estate is attempting to recover from Principal Life an amount, including interest, of approximately $500.0 million. We are one of numerous defendants to this action, which has been stayed by the bankruptcy court. We believe that we have meritorious defenses to Lehman's claims and intend to aggressively defend against them once the stay is lifted and we are allowed to do so.
	While the outcome of any pending or future litigation or regulatory matter cannot be predicted, management does not believe that any such matter will have a material adverse effect on our business or financial position. As of December 31, 2013, there were no estimated losses accrued related to the legal matters discussed above because we believe the loss from these matters is not probable and cannot be reasonably estimated.
	We believe all of the litigation contingencies discussed above involve a chance of loss that is either remote or reasonably possible. Unless otherwise noted, all of these matters involve unspecified claim amounts, in which the respective plaintiffs seek an indeterminate amount of damages. 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, 2013.
	Guarantees and Indemnifications
	In the normal course of business, we have provided guarantees to third parties primarily related to former subsidiaries and joint ventures. These agreements generally expire through 2019. The maximum exposure under these agreements as of December 31, 2013, was approximately $251.0 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 that 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.
	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, 2013 and 2012, the liability balance for guaranty fund assessments, which is not discounted, was $22.5 million and $31.0 million, respectively, and was reported within other liabilities in the consolidated statements of financial position. As of December 31, 2013 and 2012, $11.5 million and $16.5 million, respectively, related to premium tax offsets were included in premiums due and other receivables in the consolidated statements of financial position.
	Operating Leases
	As a lessee, we lease office space, data processing equipment, office furniture and office equipment under various operating leases. Rental expense for the years ended December 31, 2013, 2012 and 2011, respectively, was $36.3 million, $41.9 million and $51.1 million.
	The following represents payments due by period for operating lease obligations (in millions):
	Year ending December 31:
	2014	$	42.3
	2015		37
	2016		30.9
	2017		23.2
	2018		10.8
	2019 and thereafter		53.9
	Total operating lease obligations		198.1
	Less: Future sublease rental income on noncancelable leases		7.7
	Total future minimum lease payments	$	190.4
	Capital Leases
	We lease buildings and hardware storage equipment under capital leases. As of December 31, 2013 and 2012, these leases had a gross asset balance of $42.6 million and $35.5 million and accumulated depreciation of $16.1 million and $11.5 million, respectively. Depreciation expense for the years ended December 31, 2013, 2012 and 2011 was $10.5 million, $7.9 million and $4.4 million, respectively.
	The following represents future minimum lease payments due by period for capital lease obligations (in millions).
	Year ending December 31:
	2014	$	7.2
	2015		6.1
	2016		4.5
	2017		1.7
	2018		0.1
	Total		19.6
	Less: Amounts representing interest		0.6
	Net present value of minimum lease payments	$	19

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity	'
Stockholders' Equity	'
	14. Stockholders' Equity
	Preferred Stock
	As of December 31, 2013, we had 13.0 million shares of preferred stock authorized, issued and outstanding under the two series described below. Preferred stockholders have dividend and liquidation priority over common stockholders.
	Series A.    Dividends on the Series A Preferred Stock are non-cumulative and are payable quarterly when, and if, declared by our Board of Directors at a rate of 5.563% per annum of the liquidation preference. On or after the dividend payment date in June 2015, the Series A initial distribution rate will become a floating rate, subject to reset, at our option, subject to certain conditions and parameters. If reset, the rate may be at fixed or floating rates. On or after the dividend payment date in June 2015, we may, at our option, redeem the shares at a price of $100 per share, or $300.0 million in the aggregate, plus accrued and unpaid dividends for the then current dividend period to the date of redemption, if any.
	The Series A Preferred Stock has no stated maturity and is not convertible into any other of our securities. Series A Preferred Stock will have no voting rights, except with respect to certain fundamental changes in the terms of the shares and in the case of certain dividend non-payments.
	Series B.    Dividends on the Series B Preferred Stock are non-cumulative and are payable quarterly when, and if, declared by the Board of Directors at a rate of 6.518% per annum of the liquidation preference. On or after the dividend payment date in June 2035, the Series B initial distribution rate will become a floating rate, subject to reset, at our option, subject to certain conditions and parameters. If reset, the rate may be at fixed or floating rates. On or after the dividend payment date in June 2015, we may, at our option, redeem the shares at a price of $25 per share, or $250.0 million in the aggregate, plus accrued and unpaid dividends for the then current dividend period to the date of redemption, if any.
	The Series B Preferred Stock has no stated maturity and is not convertible into any other of our securities. Series B Preferred Stock will have no voting rights, except with respect to certain fundamental changes in the terms of the shares and in the case of certain dividend non-payments.
	Dividend Restrictions and Payments
	The certificates of designation for the Series A and B Preferred Stock restrict the declaration of preferred dividends if we fail to meet specified capital adequacy, net income or stockholders' equity levels. As of December 31, 2013, we have no preferred dividend restrictions.
	On April 1, 2013; July 1, 2013; September 30, 2013 and December 30, 2013, we paid a dividend of $8.2 million, $8.3 million, $8.2 million and $8.3 million, respectively, equal to $1.39 per share on Series A non-cumulative perpetual preferred stock and equal to $0.41 per share on Series B non-cumulative perpetual preferred stock. Dividends were paid to stockholders of record as of March 14, 2013; June 13, 2013; September 12, 2013 and December 12, 2013, respectively.
	On March 30, 2012; July 2, 2012; October 1, 2012 and December 31, 2012, we paid a dividend of $8.2 million, $8.3 million, $8.2 million and $8.3 million, respectively, equal to $1.39 per share on Series A non-cumulative perpetual preferred stock and equal to $0.41 per share on Series B non-cumulative perpetual preferred stock. Dividends were paid to stockholders of record as of March 15, 2012; June 14, 2012; September 13, 2012 and December 13, 2012, respectively.
	On March 30, 2011; June 30, 2011; September 30, 2011 and December 30, 2011, we paid a dividend of $8.2 million, $8.3 million, $8.2 million and $8.3 million, respectively, equal to $1.39 per share on Series A non-cumulative perpetual preferred stock and equal to $0.41 per share on Series B non-cumulative perpetual preferred stock. Dividends were paid to stockholders of record as of March 11, 2011; June 9, 2011; September 8, 2011 and December 8, 2011, respectively.
	Common Stock
	Date of dividend payment	Date of record		Dividend per			Common stock
				common share			dividend
							(in millions)
	2013:00:00
	December 27, 2013	December 9, 2013		$	0.26		$	76.7
	September 27, 2013	September 5, 2013			0.26			76.5
	June 28, 2013	June 3, 2013			0.23			67.6
	March 29, 2013	March 11, 2013			0.23			67.6
	2012:00:00
	December 28, 2012	December 10, 2012		$	0.21		$	61.7
	September 28, 2012	September 6, 2012			0.21			61.6
	June 29, 2012	June 11, 2012			0.18			53.7
	March 30, 2012	March 12, 2012			0.18			54.3
	2011:00:00
	December 2, 2011	November 10, 2011		$	0.7		$	213.7
	Reconciliation of Outstanding Shares
		Series A			Series B			Common
		preferred stock			preferred stock			stock
		(in millions)
	Outstanding shares at January 1, 2011		3			10			320.4
	Shares issued		—			—			1.8
	Treasury stock acquired		—			—			(21.1	)
	Outstanding shares at December 31, 2011		3			10			301.1
	Shares issued		—			—			3.2
	Treasury stock acquired		—			—			(10.5	)
	Outstanding shares at December 31, 2012		3			10			293.8
	Shares issued		—			—			5.8
	Treasury stock acquired		—			—			(4.4	)
	Outstanding shares at December 31, 2013		3			10			295.2
	In May 2011, our Board of Directors reinstated the November 2007 share repurchase program. In July 2011, we completed this program. In August 2011, our Board of Directors authorized a share repurchase program of up to $200.0 million of our outstanding common stock. We completed this program in September 2011. In November 2011, our Board of Directors authorized a share repurchase program of up to $100.0 million of our outstanding common stock. We completed this program in December 2011. In February 2012, our Board of Directors authorized a share repurchase program of up to $100.0 million of our outstanding common stock. We completed this program in May 2012. In May 2012, our Board of Directors authorized a share repurchase program of up to $200.0 million of our outstanding common stock. We completed this program in February 2013. Also in February 2013, our Board of Directors authorized a share repurchase program up to $150.0 million of our outstanding common stock.
	Our Board of Directors has authorized various repurchase programs under which we are allowed to purchase shares of our outstanding common stock. 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, 2013
		Pre-Tax			Tax			After-Tax
		(in millions)
	Net unrealized losses on available-for-sale securities during the period	$	(1,686.5	)	$	559.5		$	(1,127.0	)
	Reclassification adjustment for losses included in net income (1)		61.1			(20.9	)		40.2
	Adjustments for assumed changes in amortization patterns		252.8			(88.5	)		164.3
	Adjustments for assumed changes in policyholder liabilities		575.7			(193.4	)		382.3
	Net unrealized losses on available-for-sale securities		(796.9	)		256.7			(540.2	)
	Noncredit component of impairment losses on fixed maturities, available-for-sale during the period		24.5			(8.3	)		16.2
	Adjustments for assumed changes in amortization patterns		(14.4	)		5.1			(9.3	)
	Noncredit component of impairment losses on fixed maturities, available-for-sale (2)		10.1			(3.2	)		6.9
	Net unrealized losses on derivative instruments during the period		(46.3	)		16.8			(29.5	)
	Reclassification adjustment for losses included in net income (3)		11.6			(4.3	)		7.3
	Adjustments for assumed changes in amortization patterns		10.9			(3.8	)		7.1
	Adjustments for assumed changes in policyholder liabilities		20.5			(7.2	)		13.3
	Net unrealized losses on derivative instruments		(3.3	)		1.5			(1.8	)
	Foreign currency translation adjustment		(282.6	)		13.2			(269.4	)
Unrecognized postretirement benefit obligation during the period		426.7			(149.3	)		277.4
Amortization of prior service cost and actuarial loss included in net periodic benefit cost (4)		84.9			(29.7	)		55.2
Net unrecognized postretirement benefit obligation		511.6			(179.0	)		332.6
Other comprehensive loss	$	(561.1	)	$	89.2		$	(471.9	)
	For the year ended
	December 31, 2012
	Pre-Tax			Tax			After-Tax
	(in millions)
Net unrealized gains on available-for-sale securities during the period	$	1,577.30		$	(520.6	)	$	1,056.70
Reclassification adjustment for losses included in net income (1)		107.8			(38.4	)		69.4
Adjustments for assumed changes in amortization patterns		(169.0	)		59.1			(109.9	)
Adjustments for assumed changes in policyholder liabilities		(689.2	)		230.6			(458.6	)
Net unrealized gains on available-for-sale securities		826.9			(269.3	)		557.6
Noncredit component of impairment losses on fixed maturities, available-for-sale during the period		(17.3	)		6.1			(11.2	)
Adjustments for assumed changes in amortization patterns		4			(1.6	)		2.4
Adjustments for assumed changes in policyholder liabilities		3.2			(1.1	)		2.1
Noncredit component of impairment losses on fixed maturities, available-for-sale (2)		(10.1	)		3.4			(6.7	)
Net unrealized losses on derivative instruments during the period		(25.9	)		9.1			(16.8	)
Reclassification adjustment for losses included in net income (3)		3.4			(1.5	)		1.9
Adjustments for assumed changes in amortization patterns		25.9			(9.1	)		16.8
Adjustments for assumed changes in policyholder liabilities		(70.0	)		24.5			(45.5	)
Net unrealized losses on derivative instruments		(66.6	)		23			(43.6	)
Foreign currency translation adjustment		(25.4	)		15.6			(9.8	)
Unrecognized postretirement benefit obligation during the period		(245.7	)		86			(159.7	)
Amortization of prior service cost and actuarial loss included in net periodic benefit cost (4)		49.6			(17.3	)		32.3
Net unrecognized postretirement benefit obligation		(196.1	)		68.7			(127.4	)
Other comprehensive income	$	528.7		$	(158.6	)	$	370.1
	For the year ended
	December 31, 2011
	Pre-Tax			Tax			After-Tax
	(in millions)
Net unrealized gains on available-for-sale securities during the period	$	559.4		$	(207.9	)	$	351.5
Reclassification adjustment for losses included in net income (1)		112			(42.9	)		69.1
Adjustments for assumed changes in amortization patterns		(114.9	)		40.2			(74.7	)
Adjustments for assumed changes in policyholder liabilities		(230.3	)		93			(137.3	)
Net unrealized gains on available-for-sale securities		326.2			(117.6	)		208.6
Noncredit component of impairment losses on fixed maturities, available-for-sale during the period		49.9			(18.0	)		31.9
Adjustments for assumed changes in amortization patterns		(1.4	)		0.5			(0.9	)
Noncredit component of impairment losses on fixed maturities, available-for-sale (2)		48.5			(17.5	)		31
Net unrealized gains on derivative instruments during the period		39.6			(13.8	)		25.8
Reclassification adjustment for losses included in net income (3)		20.7			(7.4	)		13.3
Adjustments for assumed changes in amortization patterns		(23.9	)		8.4			(15.5	)
Net unrealized gains on derivative instruments		36.4			(12.8	)		23.6
Foreign currency translation adjustment		(130.8	)		(0.1	)		(130.9	)
Unrecognized postretirement benefit obligation during the period		(286.7	)		100.3			(186.4	)
Amortization of prior service cost and actuarial loss included in net periodic benefit cost (4)		20.7			(7.2	)		13.5
Net unrecognized postretirement benefit obligation		(266.0	)		93.1			(172.9	)
Other comprehensive loss	$	14.3		$	(54.9	)	$	(40.6	)
-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
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 6, Derivative Financial Instruments — Cash Flow Hedges, for further details.
-4
Pre-tax amortization of prior service cost and actuarial loss included in net periodic benefit cost, which is comprised of amortization of prior service cost (benefit) and recognized net actuarial (gain) loss, is reported in operating expenses on the consolidated statements of operations. See Note 12, Employee and Agent Benefits — Components of Net Periodic Benefit Cost, for further details.
Accumulated Other Comprehensive Income
	Net unrealized			Noncredit			Net unrealized			Foreign			Unrecognized			Accumulated
	gains on			component of			gains (losses) on			currency			postretirement			other
	available-for-sale			impairment losses			derivative			translation			benefit			comprehensive
	securities			on fixed maturities			instruments			adjustment			obligation			income
				available-for-sale
	(in millions)
Balances at January 1, 2011	$	652.1		$	(198.2	)	$	11.3		$	34.5		$	(188.2	)	$	311.5
Other comprehensive income during the period, net of adjustments		139.5			—			10.3			(130.4	)		(186.4	)		(167.0	)
Amounts reclassified from AOCI		69.1			31			13.3			—			13.5			126.9
Other comprehensive loss		208.6			31			23.6			(130.4	)		(172.9	)		(40.1	)
Balances at December 31, 2011		860.7			(167.2	)		34.9			(95.9	)		(361.1	)		271.4
Other comprehensive income during the period, net of adjustments		488.2			(6.7	)		(45.5	)		(11.0	)		(159.7	)		265.3
Amounts reclassified from AOCI		69.4			—			1.9			—			32.3			103.6
Other comprehensive income		557.6			(6.7	)		(43.6	)		(11.0	)		(127.4	)		368.9
Balances at December 31, 2012		1,418.30			(173.9	)		(8.7	)		(106.9	)		(488.5	)		640.3
Other comprehensive income during the period, net of adjustments		(580.4	)		—			(9.1	)		(254.6	)		277.4			(566.7	)
Amounts reclassified from AOCI		40.2			6.9			7.3			—			55.2			109.6
Other comprehensive loss		(540.2	)		6.9			(1.8	)		(254.6	)		332.6			(457.1	)
Balances at December 31, 2013	$	878.1		$	(167.0	)	$	(10.5	)	$	(361.5	)	$	(155.9	)	$	183.2
Noncontrolling Interest
Interest 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 subsidiaries 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 presented on the consolidated statements of financial position line item titled "Redeemable noncontrolling interest." If the interest were to be redeemed, we would be required to purchase such interest at a redemption value based on fair value or a formula that management intended to reasonably approximate fair value based on a fixed multiple of earnings over a measurement period. As such, 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):
Balance at January 1, 2011	$	—
Net income attributable to redeemable noncontrolling interest		0.2
Redeemable noncontrolling interest assumed related to acquisition		22
Balance at December 31, 2011		22.2
Net income attributable to redeemable noncontrolling interest		1.9
Redeemable noncontrolling interest assumed related to acquisition		37.2
Distributions to redeemable noncontrolling interest		(2.0	)
Foreign currency translation adjustment		1.1
Balance at December 31, 2012		60.4
Net income attributable to redeemable noncontrolling interest		13.6
Reclassification from stockholders' equity (1)		173.9
Contributions from redeemable noncontrolling interest		1.2
Distributions to redeemable noncontrolling interest		(13.9	)
Purchase of subsidiary shares from redeemable noncontrolling interest		(2.4	)
Change in redemption value of redeemable noncontrolling interest		19.2
Foreign currency translation adjustment		(4.8	)
Balance at December 31, 2013	$	247.2
-1
During the third quarter of 2013, we identified a classification error of certain of our noncontrolling interests. The classification error had no impact on net income, but did impact earnings per share to the extent the redemption value of the redeemable noncontrolling interest exceeds the fair value. We evaluated the classification error and related earnings per share impact based on qualitative and quantitative factors in accordance with SEC Staff Accounting Bulletins 99 and 108 and concluded the impact was not material in the current or any prior quarterly or annual periods presented. During the third quarter of 2013, we recorded a $173.9 million increase to redeemable noncontrolling interest and a corresponding decrease to stockholders' equity. See related discussion in Note 19, Earnings Per Share.
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. There are no significant restrictions that limit the payment of dividends by us, except those generally applicable to corporations incorporated in Delaware.
Under Iowa law, Principal Life may pay stockholder dividends only from the earned surplus arising from its business and must receive the prior approval of the Commissioner to pay a stockholder dividend if such a stockholder dividend would exceed certain statutory limitations. In general, the current statutory limitation is the greater of 10% of Principal Life's policyholder surplus as of the preceding year-end or the net gain from operations from the previous calendar year. Based on this limitation and 2013 statutory results, Principal Life could pay approximately $687.2 million in stockholder dividends in 2014 without exceeding the statutory limitation.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Measurements	'
Fair Value Measurements	'
	15. 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-type insurance 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. Our Level 1 assets and liabilities primarily include exchange traded equity securities, mutual funds and U.S. Treasury bonds.
	•
	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. Our Level 2 assets and liabilities primarily include fixed maturities (including public and private bonds), equity securities, derivatives and other investments for which public quotations are not available but that are priced by third-party pricing services or internal models using substantially all observable inputs.
	•
	Level 3 — Fair values are based on significant unobservable inputs for the asset or liability. Our Level 3 assets and liabilities include certain assets and liabilities priced using broker quotes or other valuation methods that utilize at least one significant unobservable input. These include fixed maturities, private equity securities, real estate and commercial mortgage loan investments of our separate accounts, commercial mortgage loan investments and obligations of consolidated VIEs for which the fair value option was elected, complex derivatives, embedded derivatives and equity method real estate investments for which the fair value option was elected.
	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 or disclosed at fair value. The techniques utilized in estimating the fair values 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 2013.
	Fixed Maturities
	Fixed maturities include bonds, ABS, redeemable preferred stock and certain nonredeemable 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 where 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 actually 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, which are reflected in Level 3 and can include fixed maturities across all asset classes. As of December 31, 2013, less than 1% of our fixed maturities were valued using internal pricing models, which were classified as Level 3 assets accordingly.
	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.    Inputs include recently executed market transactions, interest rate yield curves, maturity dates, market price quotations and credit spreads relating to similar instruments.
	States and Political Subdivisions.    Inputs include Municipal Securities Rulemaking Board reported trades, U.S. Treasury and other benchmark curves, material event notices, new issue data and obligor credit ratings.
	Corporate.    Inputs include recently executed transactions, market price quotations, benchmark yields, issuer spreads and observations of equity and credit default swap curves related to the issuer. For private placement corporate securities valued through the matrix valuation approach inputs include the current Treasury curve and risk spreads based on sector, rating and average life of the issuance.
	RMBS, CMBS, Collateralized Debt Obligations and Other Debt Obligations.    Inputs include cash flows, priority of the tranche in the capital structure, expected time to maturity for the specific tranche, reinvestment period remaining and performance of the underlying collateral including prepayments, defaults, deferrals, loss severity of defaulted collateral and, for RMBS, prepayment speed assumptions. Other inputs include market indices and recently executed market transactions.
	Equity Securities
	Equity securities include mutual funds, common stock, nonredeemable preferred stock and mandatory regulatory required 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, 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 such that their fair value is not reflected in the consolidated statements of financial position. The fair values of derivative instruments cleared through centralized clearinghouses 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. 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 non-performance risk is appropriate. Our centrally cleared derivative contracts are conducted with regulated centralized clearinghouses, which provide for daily exchange of cash collateral equal to the difference in the daily market values of those contracts that eliminates the non-performance risk on these trades.
	Interest Rate Contracts.    For non-cleared contracts we use discounted cash flow valuation techniques to determine the fair value of interest rate swaps using observable swap curves as the inputs. These are reflected in Level 2. For centrally cleared contracts we use published prices from clearinghouses. These are reflected in Level 2. In addition, we have a limited number of complex inflation-linked interest rate swaps, interest rate collars and swaptions that are valued using broker quotes. These are reflected in Level 3.
	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 valued using observable market inputs, including forward currency exchange rates. These are reflected in Level 2. In addition, we have a limited number of currency options and non-standard currency swaps that are 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 or broker prices to determine the fair value of credit default swaps. These are reflected in Level 3. In addition, we have a limited number of total return swaps that are valued based on the observable quoted price of underlying equity indices. These are reflected in Level 2.
	Other Investments
	Other investments reported at fair value primarily include seed money investments, for which the fair value is determined using the net asset value of the fund. The net asset value of the fund represents the price at which we feel we would be able to initiate a transaction. Seed money investments in mutual funds for which the net asset value is published are reflected in Level 1. Seed money investments in mutual funds or other investment funds in markets that do not have a published net asset value are reflected in Level 2.
	Other investments reported at fair value also include commercial mortgage loans of consolidated VIEs and equity method real estate investments for which the fair value option was elected, which are reflected in Level 3. Fair value of the commercial mortgage loans is computed utilizing a discount rate based on the current market. The market discount rate is then adjusted based on various factors that differentiate it from our pool of loans. 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.
	Cash and 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 less than three months. 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 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 public real estate market data inputs such as transaction prices, market rents, vacancy levels, leasing absorption, market cap rates and discount rates. 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-Type Insurance Contracts
	Certain annuity contracts and other investment-type insurance contracts include embedded derivatives that have been bifurcated from the host contract and that 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 stochastic models that incorporate a spread reflecting our own creditworthiness.
	The assumption for our own non-performance risk for investment-type insurance contracts and any embedded derivatives bifurcated from certain annuity and investment-type insurance contracts is based on the current market credit spreads for debt-like instruments that we have issued and are available in the market.
	Other Liabilities
	Certain obligations reported in other liabilities include embedded derivatives to deliver underlying securities of structured investments to third parties. The fair value of the embedded derivatives is calculated based on the value of the underlying securities that are 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 are reflected in Level 2.
	Additionally, obligations of consolidated VIEs for which the fair value option was elected are included in other liabilities. These obligations are valued either 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 are reflected in Level 2, or broker quotes, which are reflected in Level 3.
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	Assets and liabilities measured at fair value on a recurring basis are summarized below.
		As of December 31, 2013
		Assets/			Fair value hierarchy level
		(liabilities)
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	780.5		$	409.3		$	371.2		$	—
	Non-U.S. governments		996.8			—			949.3			47.5
	States and political subdivisions		3,658.00			—			3,656.20			1.8
	Corporate		31,919.00			40.3			31,714.70			164
	Residential mortgage-backed securities		2,845.20			—			2,845.20			—
	Commercial mortgage-backed securities		4,026.40			—			4,024.80			1.6
	Collateralized debt obligations		363.4			—			325.6			37.8
	Other debt obligations		4,167.80			—			4,083.70			84.1
	Total fixed maturities, available-for-sale		48,757.10			449.6			47,970.70			336.8
Fixed maturities, trading		563.1			—			393.2			169.9
Equity securities, available-for-sale		110.5			38.1			55.5			16.9
Equity securities, trading		716.9			105.1			611.8			—
Derivative assets (1)		665.1			—			590.9			74.2
Other investments (2)		361.1			6.8			211.4			142.9
Cash equivalents (3)		1,459.00			—			1,459.00			—
Sub-total excluding separate account assets		52,632.80			599.6			51,292.50			740.7
Separate account assets		130,018.40			67,215.10			57,538.10			5,265.20
Total assets	$	182,651.20		$	67,814.70		$	108,830.60		$	6,005.90
Liabilities
Investment-type insurance contracts (4)	$	(6.9	)	$	—		$	—		$	(6.9	)
Derivative liabilities (1)		(1,024.6	)		—			(985.0	)		(39.6	)
Other liabilities (4)		(322.1	)		—			(248.2	)		(73.9	)
Total liabilities	$	(1,353.6	)	$	—		$	(1,233.2	)	$	(120.4	)
Net assets (liabilities)	$	181,297.60		$	67,814.70		$	107,597.40		$	5,885.50
	As of December 31, 2012
	Assets/			Fair value hierarchy level
	(liabilities)
	measured at
	fair value			Level 1			Level 2			Level 3
	(in millions)
Assets
Fixed maturities, available-for-sale:
U.S. government and agencies	$	944.3		$	203.5		$	740.8		$	—
Non-U.S. governments		1,208.30			—			1,164.00			44.3
States and political subdivisions		3,178.80			—			3,176.90			1.9
Corporate		34,325.40			85.9			34,065.00			174.5
Residential mortgage-backed securities		3,226.70			—			3,226.70			—
Commercial mortgage-backed securities		3,897.40			—			3,897.40			—
Collateralized debt obligations		379.2			—			301.6			77.6
Other debt obligations		3,779.20			—			3,764.50			14.7
Total fixed maturities, available-for-sale		50,939.30			289.4			50,336.90			313
Fixed maturities, trading		626.7			9.4			450.5			166.8
Equity securities, available-for-sale		136.5			54.4			66.8			15.3
Equity securities, trading		252.8			99.8			153			—
Derivative assets (1)		1,016.70			—			941.6			75.1
Other investments (2)		272.1			64.1			94.1			113.9
Cash equivalents (3)		1,772.60			561.4			1,211.20			—
Sub-total excluding separate account assets		55,016.70			1,078.50			53,254.10			684.1
Separate account assets		81,653.80			54,010.10			23,027.70			4,616.00
Total assets	$	136,670.50		$	55,088.60		$	76,281.80		$	5,300.10
Liabilities
Investment-type insurance contracts (4)	$	(170.5	)	$	—		$	—		$	(170.5	)
Derivative liabilities (1)		(1,205.1	)		—			(1,102.5	)		(102.6	)
Other liabilities (4)		(237.4	)		—			(197.8	)		(39.6	)
Total liabilities	$	(1,613.0	)	$	—		$	(1,300.3	)	$	(312.7	)
Net assets (liabilities)	$	135,057.50		$	55,088.60		$	74,981.50		$	4,987.40
-1
Within the consolidated statements of financial position, derivative assets are reported with other investments and derivative liabilities are reported with other liabilities. Refer to Note 6, Derivative Financial Instruments, for further information on fair value by class of derivative instruments. Our derivatives are primarily Level 2, with the exception of certain credit default swaps and other swaps that are Level 3.
-2
Primarily includes seed money investments, commercial mortgage loans of consolidated VIEs and equity method investments reported at fair value.
-3
Includes money market instruments and short-term investments with a maturity date of three months or less when purchased.
-4
Includes bifurcated embedded derivatives that are reported at fair value within the same line item in the consolidated statements of financial position in which the host contract is reported. Other liabilities also include obligations of consolidated VIEs reported at fair value.
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) are summarized as follows:
	For the year ended December 31, 2013
	Beginning			Total realized/unrealized gains (losses)															Ending			Changes in
	asset/																		asset/			unrealized
	(liability)																		(liability)			gains (losses)
	balance as of																		balance as of			included in
	December 31,																		December 31,			net income
	2012									Net purchases,									2013			relating to positions
										sales,												still held (1)
										issuances
										and
				Included			Included			settlements (4)			Transfers			Transfers
				in net			in other						into			out of
				income (1)			comprehensive						Level 3			Level 3
							income
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	44.3		$	(0.1	)	$	(0.9	)	$	4.2		$	—		$	—		$	47.5		$	(0.1	)
States and political subdivisions		1.9			—			—			(0.1	)		—			—			1.8			—
Corporate		174.5			(13.4	)		4.5			(23.0	)		105.3			(83.9	)		164			(10.4	)
Commercial mortgage-backed securities		—			—			(0.1	)		(0.7	)		2.4			—			1.6			—
Collateralized debt obligations		77.6			2.1			7.2			(56.0	)		31.7			(24.8	)		37.8			—
Other debt obligations		14.7			(0.3	)		2.8			34.9			32			—			84.1			(0.3	)
Total fixed maturities, available-for-sale		313			(11.7	)		13.5			(40.7	)		171.4			(108.7	)		336.8			(10.8	)
Fixed maturities, trading		166.8			3			—			0.1			—			—			169.9			3.1
Equity securities, available-for-sale		15.3			(0.2	)		1.8			—			—			—			16.9			(0.2	)
Derivative assets		75.1			(19.5	)		—			18.6			—			—			74.2			(19.8	)
Other investments		113.9			11.2			—			17.8			—			—			142.9			11.2
Separate account assets (2)		4,616.00			574.9			(0.1	)		68.2			12.7			(6.5	)		5,265.20			545.8
Liabilities
Investments-type insurance contracts		(170.5	)		147.3			—			16.3			—			—			(6.9	)		145
Derivative liabilities		(102.6	)		55			(0.1	)		8.1			—			—			(39.6	)		53.9
Other liabilities (3)		(39.6	)		(34.3	)		—			—			—			—			(73.9	)		(34.3	)
	For the year ended December 31, 2012
																						Changes in
																						unrealized
																						gains (losses)
																						included in
																						net income
	Beginning			Total realized/unrealized gains (losses)															Ending			relating to
	asset/																		asset/			positions
	(liability)																		(liability)			still held (1)
	balance as of																		balance as of
	December 31,									Net purchases,									December 31,
	2011									sales,									2012
										issuances
										and
				Included			Included			settlements (4)			Transfers			Transfers
				in net			in other						into			out of
				income (1)			comprehensive						Level 3			Level 3
							income
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	22.9		$	(0.2	)	$	(0.3	)	$	7.4		$	14.5		$	—		$	44.3		$	(0.1	)
States and political subdivisions		—			—			0.2			(0.1	)		1.8			—			1.9			—
Corporate		297			(9.2	)		19.9			(75.5	)		79.7			(137.4	)		174.5			(2.6	)
Collateralized debt obligations		102.5			(3.3	)		5.1			4.5			—			(31.2	)		77.6			—
Other debt obligations		27.3			(2.3	)		0.6			(26.2	)		15.3			—			14.7			(2.2	)
Total fixed maturities, available-for-sale		449.7			(15.0	)		25.5			(89.9	)		111.3			(168.6	)		313			(4.9	)
Fixed maturities, trading		220.8			3.2			—			(66.7	)		9.5			—			166.8			(4.4	)
Equity securities, available-for-sale		18			(0.3	)		(2.4	)		—			—			—			15.3			—
Derivative assets		60.2			2.9			—			12			—			—			75.1			4.9
Other investments		97.5			2.1			—			14.3			—			—			113.9			2.2
Separate account assets (2)		4,198.20			421.3			0.4			(3.6	)		1.6			(1.9	)		4,616.00			412.8
Liabilities
Investments-type insurance contracts		(195.8	)		38.3			(0.1	)		(12.9	)		—			—			(170.5	)		35.3
Derivative liabilities		(177.1	)		39.8			1.3			33.4			—			—			(102.6	)		38.6
Other liabilities (3)		(24.2	)		(23.5	)		—			8.1			—			—			(39.6	)		(20.2	)
	For the year ended December 31, 2011																					Changes in
																						unrealized
																						gains (losses)
																						included
																						in net
																						income
	Beginning			Total realized/unrealized gains (losses)															Ending			relating to
	asset/																		asset/			positions
	(liability)																		(liability)			still held (1)
	balance as of																		balance as of
	December 31,									Net purchases,									December 31,
	2010									sales,									2011
										issuances
										and
				Included			Included			settlements (4)			Transfers			Transfers
				in net			in other						into			out of
				income (1)			comprehensive						Level 3			Level 3
							income
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	24.5		$	0.2		$	—		$	(1.8	)	$	—		$	—		$	22.9		$	0.1
Corporate		552.1			(10.8	)		(20.8	)		(42.7	)		103.2			(284.0	)		297			(6.1	)
Commercial mortgage-backed securities		16.2			(3.7	)		5.1			(10.5	)		—			(7.1	)		—			—
Collateralized debt obligations		109.3			(19.6	)		13.8			0.3			—			(1.3	)		102.5			(9.3	)
Other debt obligations		88.8			0.1			(1.1	)		(30.5	)		9			(39.0	)		27.3			—
Total fixed maturities, available-for-sale		790.9			(33.8	)		(3.0	)		(85.2	)		112.2			(331.4	)		449.7			(15.3	)
Fixed maturities, trading		269.1			(16.6	)		—			(27.2	)		20.5			(25.0	)		220.8			(15.8	)
Equity securities, available-for-sale		43.2			(6.1	)		12			(28.0	)		13			(16.1	)		18			(4.5	)
Derivative assets		33.3			37.8			(0.1	)		(10.8	)		—			—			60.2			33.4
Other investments		128.3			(2.5	)		—			(28.3	)		—			—			97.5			(2.6	)
Separate account assets (2)		3,771.50			406.6			—			88.9			13.5			(82.3	)		4,198.20			400.9
Liabilities
Investments-type insurance contracts		(6.6	)		(206.3	)		—			17.1			—			—			(195.8	)		(206.6	)
Derivative liabilities		(181.5	)		(11.4	)		0.2			15.6			—			—			(177.1	)		(8.6	)
Other liabilities (3)		(156.8	)		(1.2	)		13.4			(15.9	)		—			136.3			(24.2	)		(1.1	)
-1
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 fixed maturities, trading and certain derivatives used in relation to certain trading portfolios are reported in net investment income within the consolidated statements of operation.
-2
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.
-3
Certain embedded derivatives reported in other liabilities are part of a cash flow hedge, with the effective portion of the unrealized gains (losses) recorded in AOCI.
-4
Gross purchases, sales, issuances and settlements were:
	For the year ended December 31, 2013
	Purchases			Sales			Issuances			Settlements			Net purchases,
													sales, issuances
													and settlements
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. government	$	9.3		$	(3.9	)	$	—		$	(1.2	)	$	4.2
State and political subdivisions		—			—			—			(0.1	)		(0.1	)
Corporate		32.6			(33.3	)		—			(22.3	)		(23.0	)
Commercial mortgage-backed securities		—			—			—			(0.7	)		(0.7	)
Collateralized debt obligations		17			(47.4	)		—			(25.6	)		(56.0	)
Other debt obligations		37.8			—			—			(2.9	)		34.9
Total fixed maturities, available-for-sale		96.7			(84.6	)		—			(52.8	)		(40.7	)
Fixed maturities, trading		—			—			—			0.1			0.1
Derivative assets		22.1			(3.5	)		—			—			18.6
Other investments		30.2			—			—			(12.4	)		17.8
Separate account assets (5)		418.4			(300.8	)		(21.8	)		(27.6	)		68.2
Liabilities
Investment-type insurance contracts		—			—			11			5.3			16.3
Derivative liabilities		(3.4	)		11.5			—			—			8.1
	For the year ended December 31, 2012
	Purchases			Sales			Issuances			Settlements			Net purchases,
													sales, issuances
													and settlements
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. government	$	13.5		$	(5.0	)	$	—		$	(1.1	)	$	7.4
State and political subdivisions		—			—			—			(0.1	)		(0.1	)
Corporate		29.2			(92.0	)		—			(12.7	)		(75.5	)
Collateralized debt obligations		5.1			(1.1	)		—			0.5			4.5
Other debt obligations		—			—			—			(26.2	)		(26.2	)
Total fixed maturities, available-for-sale		47.8			(98.1	)		—			(39.6	)		(89.9	)
Fixed maturities, trading		—			(24.6	)		—			(42.1	)		(66.7	)
Derivative assets		12.6			(0.6	)		—			—			12
Other investments		34			—			—			(19.7	)		14.3
Separate account assets (5)		342.2			(310.6	)		(208.4	)		173.2			(3.6	)
Liabilities
Investment-type insurance contracts		—			—			(16.6	)		3.7			(12.9	)
Derivative liabilities		(8.9	)		42.3			—			—			33.4
Other liabilities		—			8.1			—			—			8.1
	For the year ended December 31, 2011
	Purchases			Sales			Issuances			Settlements			Net purchases,
													sales, issuances
													and settlements
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. government	$	3.6		$	(5.4	)	$	—		$	—		$	(1.8	)
Corporate		21.2			(25.6	)		—			(38.3	)		(42.7	)
Commercial mortgage-backed securities		—			(10.5	)		—			—			(10.5	)
Collateralized debt obligations		1.3			(0.4	)		—			(0.6	)		0.3
Other debt obligations		—			—			—			(30.5	)		(30.5	)
Total fixed maturities, available-for-sale		26.1			(41.9	)		—			(69.4	)		(85.2	)
Fixed maturities, trading		10			(8.7	)		—			(28.5	)		(27.2	)
Equity securities, available-for-sale		0.3			(28.3	)		—			—			(28.0	)
Derivative assets		19			(29.8	)		—			—			(10.8	)
Other investments		—			—			—			(28.3	)		(28.3	)
Separate account assets		342.7			(191.8	)		—			(62.0	)		88.9
Liabilities
Investment-type insurance contracts		—			—			9.2			7.9			17.1
Derivative liabilities		(12.1	)		27.7			—			—			15.6
Other liabilities		(2.1	)		—			—			(13.8	)		(15.9	)
-5
Issuances and settlements include amounts related to mortgage encumbrances associated with real estate in our separate accounts.
Transfers
Transfers of assets and liabilities measured at fair value on a recurring basis between fair value hierarchy levels are summarized below.
	For the year ended December 31, 2013
	Transfers out			Transfers out			Transfers out			Transfers out			Transfers out			Transfers out
	of Level 1 into			of Level 1 into			of Level 2 into			of Level 2 into			of Level 3 into			of Level 3 into
	Level 2			Level 3			Level 1			Level 3			Level 1			Level 2
	(in millions)
Assets
Fixed maturities, available-for-sale:
Corporate	$	—		$	—		$	—		$	105.3		$	—		$	83.9
Commercial mortgage-backed securities		—			—			—			2.4			—			—
Collateralized debt obligations		—			—			—			31.7			—			24.8
Other debt obligations		—			—			—			32			—			—
Total fixed maturities, available-for-sale		—			—			—			171.4			—			108.7
Separate account assets		253.9			0.1			15.5			12.6			—			6.5
	For the year ended December 31, 2012
	Transfers out			Transfers out			Transfers out			Transfers out			Transfers out			Transfers out
	of Level 1 into			of Level 1 into			of Level 2 into			of Level 2 into			of Level 3 into			of Level 3 into
	Level 2			Level 3			Level 1			Level 3			Level 1			Level 2
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	—		$	—		$	—		$	14.5		$	—		$	—
States and political subdivisions		—			—			—			1.8			—			—
Corporate		—			—			—			79.7			—			137.4
Collateralized debt obligations		—			—			—			—			—			31.2
Other debt obligations		—			—			—			15.3			—			—
Total fixed maturities, available-for-sale		—			—			—			111.3			—			168.6
Fixed maturities, trading		—			—			—			9.5			—			—
Separate account assets		3,255.70			0.3			205.5			1.3			—			1.9
Transfers between fair value hierarchy levels are recognized at the beginning of the reporting period.
We had significant transfers of separate account assets between Level 1 and Level 2, primarily related to foreign equity securities. When these securities are valued at the local close price of the exchange where the assets traded, they are reflected in Level 1. When events materially affecting the value occur between the close of the local exchange and the New York Stock Exchange, we use adjusted prices determined by a third party pricing vendor to update the foreign market closing prices and the fair value is reflected in Level 2. During 2011, $2,796.1 million of separate account assets transferred out of Level 2 into Level 1. During 2011, $3,595.9 million, of separate account assets transferred out of Level 1 into Level 2.
Assets transferred into Level 3 during 2013, 2012 and 2011, primarily included those assets for which we are now unable to obtain pricing from a recognized third party pricing vendor as well as assets that were previously priced using a matrix valuation approach that may no longer be relevant when applied to asset-specific situations.
Assets transferred out of Level 3 during 2013, 2012 and 2011, included those for which we are now able to obtain pricing from a recognized third party pricing vendor or from internal models using substantially all market observable information.
Quantitative Information about Level 3 Fair Value Measurements
The following table provides quantitative information about the significant unobservable inputs used for recurring fair value measurements categorized within Level 3, excluding assets and liabilities for which significant quantitative unobservable inputs are not developed internally, which primarily consists of those valued using broker quotes. Refer to "Assets and liabilities measured at fair value on a recurring basis" for a complete valuation hierarchy summary.
	As of December 31, 2013
	Assets /			Valuation		Unobservable		Input/range of		Weighted
	(liabilities)			technique(s)		input description		inputs		average
	measured at
	fair value
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	11.7		Discounted cash flow		Discount rate (1)		2.00%		2.00%
						Illiquidity premium		50 basis points ("bps")		50bps
Corporate		70.1		Discounted cash flow		Discount rate (1)		1.9% - 7.7%		4.40%
						Earnings before interest, taxes, depreciation and amortization multiple		0x - 4.5x		0.2x
						Comparability adjustment		0 - 125bps		43bps
						Probability of default		0% - 100%		5.40%
						Potential loss severity		0% - 16%		0.90%
						Illiquidity premium		0bps - 25bps		15bps
Commercial mortgage-backed securities		1.6		Discounted cash flow		Discount rate (1)		1.5% - 4.5%		0.00%
Collateralized debt obligations		13.6		Discounted cash flow		Discount rate (1)		1.50%		1.50%
						Illiquidity premium		400bps		400bps
Other debt obligations		33.6		Discounted cash flow		Discount rate (1)		2.0% - 15.0%		6.70%
						Illiquidity premium		0bps - 50bps		11bps
Fixed maturities, trading		36.2		Discounted cash flow		Discount rate (1)		1.6% - 83.0%		3.40%
						Illiquidity premium		0bps - 1,400bps		370bps
		110.4		See note (2)
Other investments		68.1		Discounted cash flow — commercial mortgage loans of consolidated VIEs		Discount rate (1)		4.80%		4.80%
						Illiquidity premium		94bps		94bps
		74.8		Discounted cash flow — equity method real estate investments		Discount rate (1)		7.8% - 8.1%		7.90%
						Terminal capitalization rate		5.5% - 6.8%		6.10%
						Average market rent growth rate		3.5% - 3.6%		3.60%
				Discounted cash flow — equity method real estate investment — debt		Loan to value		40.5% - 61.0%		50.70%
						Credit spread rate		1.5% - 2.0%		1.80%
Separate account assets		5,090.40		Discounted cash flow — mortgage loans		Discount rate (1)		0.6% - 5.6%		3.30%
						Illiquidity premium		0bps - 60bps		12bps
						Credit spread rate		32bps - 440bps		214bps
				Discounted cash flow — real estate		Discount rate (1)		6.0% - 16.0%		7.60%
						Terminal capitalization rate		4.5% - 9.0%		6.60%
						Average market rent growth rate		2.4% - 4.7%		3.00%
				Discounted cash flow — real estate debt		Loan to value		11.0% - 55.9%		50.30%
						Credit spread rate		1.5% - 5.2%		3.30%
Liabilities
Investment-type insurance contracts		(6.9	)	Discounted cash flow		Long duration interest rate		3.8% - 3.9% (3)
						Long-term equity market volatility		15.0% - 40.1%
						Non-performance risk		0.2% - 1.2%
						Utilization rate		See note (4)
						Lapse rate		0.5% - 14.6%
						Mortality rate		See note (5)
Derivative liabilities		(19.9	)	See note (2)
Other liabilities		(73.9	)	See note (2)
	As of December 31, 2012
	Assets /			Valuation		Unobservable		Input/range of		Weighted
	(liabilities)			technique(s)		input description		inputs		average
	measured at
	fair value
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	12.9		Discounted cash flow		Discount rate (1)		1.60%		1.60%
						Illiquidity premium		50 basis points ("bps")		50bps
Corporate		66.6		Discounted cash flow		Discount rate (1)		1.7% - 29.0%		8.40%
						Illiquidity premium		0bps - 100bps		39bps
						Earnings before interest, taxes, depreciation and amortization multiple		0x - 3.5x		0.2x
						Probability of default		0% - 100%		6.40%
						Potential loss severity		0% - 30%		1.90%
Collateralized debt obligations		38.2		Discounted cash flow		Discount rate (1)		1.0% - 19.8%		13.30%
						Illiquidity premium		400bps - 1,000bps		791bps
Other debt obligations		14.7		Discounted cash flow		Discount rate (1)		6.5% - 20.0%		11.80%
						Illiquidity premium		0bps - 50bps		30bps
Fixed maturities, trading		35.9		Discounted cash flow		Discount rate (1)		1.2% - 60.5%		4.10%
						Illiquidity premium		0bps - 1,400bps		390bps
		110.4		See note (2)
Other investments		80.3		Discounted cash flow — commercial mortgage loans of consolidated VIEs		Discount rate (1)		3.50%		3.50%
						Illiquidity premium		287bps		287bps
		33.6		Discounted cash flow — equity method real estate investment		Discount rate (1)		9.30%		9.30%
						Terminal capitalization rate		5.50%		5.50%
						Average market rent growth rate		3.60%		3.60%
				Discounted cash flow — equity method real estate investment debt		Loan to value		49.40%		49.40%
						Credit spread rate		3.30%		3.30%
Separate account assets		4,449.00		Discounted cash flow — mortgage loans		Discount rate (1)		0.8% - 10.4%		3.30%
						Illiquidity premium		0bps - 50bps		20bps
						Credit spread rate		44bps - 975bps		286bps
				Discounted cash flow — real estate		Discount rate (1)		6.5% - 16.0%		8.30%
						Terminal capitalization rate		4.8% - 9.0%		7.20%
						Average market rent growth rate		2.3% - 5.5%		3.30%
				Discounted cash flow — real estate debt		Loan to value		17.0% - 86.0%		54.80%
						Credit spread rate		1.6% - 5.3%		3.50%
Liabilities
Investment-type insurance contracts		(170.5	)	Discounted cash flow		Long duration interest rate		2.6% - 2.8% (3)
						Long-term equity market volatility		16.1% - 38.3%
						Non-performance risk		0.3% - 1.6%
						Utilization rate		See note (4)
						Lapse rate		0.5% - 14.6%
						Mortality rate		See note (5)
Derivative liabilities		(65.1	)	See note (2)
Other liabilities		(39.6	)	See note (2)
-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 credit spread, illiquidity or other adjustments, where applicable.
-2
Relates to a consolidated collateralized private investment vehicle that is a VIE. Fixed maturities, trading represents the underlying collateral of the investment structure and consists of high-grade fixed maturity investments, which are over-collateralized based on outstanding notes priced at par. The derivative liability represents credit default swaps that are valued using a correlation model to the credit default swap ("CDS") Index ("CDX") and inputs to the valuation are based on observable market data such as the end of period swap curve, CDS constituents of the index and spread levels of the index, as well as CDX tranche spreads. The other liabilities represent obligations to third party note holders due at maturity or termination of the trust. The value of the obligations reflect the third parties' interest in the investment structure.
-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 observable 20 and 30-year 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.
Market comparable discount rates are used as the base rate in the discounted cash flows used to determine the fair value of certain assets. Increases or decreases in the credit spreads on the comparable assets could cause the fair value of the assets to significantly decrease or increase, respectively. Additionally, we may adjust the base discount rate or the modeled price by applying an illiquidity premium given the highly structured nature of certain assets. Increases or decreases in this illiquidity premium could cause significant decreases or increases, respectively, in the fair value of the asset.
Embedded derivatives can be either assets or liabilities within the investment-type insurance contracts line item, depending on certain inputs at the reporting date. Increases to an asset or decreases to a liability are described as increases to fair value. Increases or decreases in market volatilities could cause significant decreases or increases, respectively, in the fair value of embedded derivatives in investment-type insurance contracts. Long duration interest rates are used as the mean return when projecting the growth in the value of associated account value and impact the discount rate used in the discounted future cash flows valuation. The amount of claims will increase if account value is not sufficient to cover guaranteed withdrawals. Increases or decreases in risk free rates could cause the fair value of the embedded derivative to significantly increase or decrease, respectively. Increases or decreases in our own credit risks, which impact the rates used to discount future cash flows, could significantly increase or decrease, respectively, the fair value of the embedded derivative. All of these changes in fair value would impact net income.
Decreases or increases in the mortality rate assumption could cause the fair value of the embedded derivative to decrease or increase, respectively. Decreases or increases in the overall lapse rate assumption could cause the fair value of the embedded derivative to decrease or increase, respectively. The lapse rate assumption varies dynamically based on the relationship of the guarantee and associated account value. A stronger or weaker dynamic lapse rate assumption could cause the fair value of the embedded derivative to decrease or increase, respectively. The utilization rate assumption includes how many contractholders will take withdrawals, when they will take them and how much of their benefit they will take. Increases or decreases in the assumption of the number of contractholders taking withdrawals could cause the fair value of the embedded derivative to decrease or increase, respectively. Assuming contractholders take withdrawals earlier or later could cause the fair value of the embedded derivative to decrease or increase, respectively. Assuming contractholders take more or less of their benefit could cause the fair value of the embedded derivative to decrease or increase, respectively.
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Certain assets are measured at fair value on a nonrecurring basis. During 2013, certain mortgage loans had been marked to fair value of $153.1 million. The net impact of impairments and improvements in estimated fair value of previously impaired loans resulted in a net loss of $27.5 million that was recorded in net realized capital gains (losses) as part of the mortgage loan valuation allowance. This includes the impact of certain loans no longer on our books. These collateral-dependent mortgage loans are a Level 3 fair value measurement, as fair value is based on the fair value of the underlying real estate collateral, which is estimated using appraised values that involve significant unobservable inputs. The fair value of the underlying collateral is determined based on a discounted cash flow valuation either from an external broker opinion of value or an internal model. Significant inputs used in the discounted cash flow calculation include: a discount rate, terminal capitalization rate and average market rent growth. The ranges of inputs used in the fair value measurements for the mortgage loans marked to fair value during 2013 were:
Discount rate =.0% - 20.0%
Terminal capitalization rate =.3% - 10.5%
Average market rent growth =.0% - 10.9%
During 2013, certain mortgage servicing rights had been marked to fair value of $7.3 million. The net impact of impairments and subsequent improvements in estimated fair value of previously impaired mortgage servicing rights resulted in a net gain of $1.3 million that was recorded in operating expenses. These mortgage servicing rights are a Level 3 fair value measurement, as fair value is determined by calculating the present value of the future servicing cash flows from the underlying mortgage loans. The discount rate used in calculating the present value of the future servicing cash flows was 4.3% for the year ended December 31, 2013.
During 2012, certain mortgage loans had been marked to fair value of $173.8 million. The net impact of impairments and improvements in estimated fair value of previously impaired loans resulted in a net loss of $12.3 million that was recorded in net realized capital gains (losses) as part of the mortgage loan valuation allowance. This includes the impact of certain loans no longer on our books. These collateral-dependent mortgage loans are a Level 3 fair value measurement, as fair value is based on the fair value of the underlying real estate collateral, which is estimated using appraised values that involve significant unobservable inputs. The fair value of the underlying collateral is determined based on a discounted cash flow valuation either from an external broker opinion of value or an internal model. Significant inputs used in the discounted cash flow calculation include: a discount rate, terminal capitalization rate and average market rent growth. The ranges of inputs used in the fair value measurements for the mortgage loans marked to fair value during 2012 were:
Discount rate =.0% - 20.0%
Terminal capitalization rate =.3% - 10.5%
Average market rent growth =.0% - 8.0%
During 2012, certain mortgage servicing rights had been marked to fair value of $7.0 million. The net impact of impairments and subsequent improvements in estimated fair value of previously impaired mortgage servicing rights resulted in a net gain of $0.4 million that was recorded in operating expenses. These mortgage servicing rights are a Level 3 fair value measurement, as fair value is determined by calculating the present value of the future servicing cash flows from the underlying mortgage loans. The discount rate used in calculating the present value of the future servicing cash flows was 3.1% for the year ended December 31, 2012.
During 2012, certain real estate had been written down to fair value of $5.0 million. This write down resulted in a loss of $0.1 million that was recorded in net realized capital gains (losses). This is a Level 3 fair value measurement, as the fair value of real estate is estimated using appraised values that involve significant unobservable inputs that are not developed internally.
During 2011, certain mortgage loans had been marked to fair value of $206.0 million. The net impact of impairments and improvements in estimated fair value of previously impaired loans resulted in a net loss of $27.7 million that was recorded in net realized capital gains (losses) as part of the mortgage loan valuation allowance. This includes the impact of certain loans no longer on our books. These collateral-dependent mortgage loans are a Level 3 fair value measurement, as fair value is based on the fair value of the underlying real estate collateral, which is estimated using appraised values that involve significant unobservable inputs.
During 2011, certain mortgage servicing rights had been written down to fair value of $4.4 million. The net impact of impairments and improvements in estimated fair value of previously impaired mortgage servicing rights resulted in a net loss of $1.1 million that was recorded in operating expenses. These mortgage servicing rights are a Level 3 fair value measurement, as fair value is determined by calculating the present value of the future servicing cash flows from the underlying mortgage loans.
During 2011, certain real estate had been written down to fair value of $3.9 million. This write down resulted in a loss of $0.6 million that was recorded in net realized capital gains (losses). This is a Level 3 fair value measurement, as the fair value of real estate is estimated using appraised values that involve significant unobservable inputs that are not developed internally.
Fair Value Option
As a result of our implementation of new authoritative guidance related to the accounting for VIEs effective January 1, 2010, we elected fair value accounting for certain assets and liabilities of consolidated VIEs for which it was not practicable for us to determine the carrying value. The fair value option was elected for commercial mortgage loans reported with other investments and obligations reported with other liabilities in the consolidated statements of financial position. The changes in fair value of these items are reported in net realized capital gains (losses) on the consolidated statements of operations.
The fair value and aggregate contractual principal amounts of commercial mortgage loans for which the fair value option has been elected were $68.1 million and $64.0 million as of December 31, 2013, and $80.3 million and $76.4 million as of December 31, 2012, respectively. The change in fair value of the loans resulted in a $0.2 million, $2.6 million and ($2.6) million pre-tax gain (loss) for the years ended December 31, 2013, 2012 and 2011, respectively, none of which related to instrument-specific credit risk. None of these loans were more than 90 days past due or in nonaccrual status. Interest income on these commercial mortgage loans is included in net investment income on the consolidated statements of operations and is recorded based on the effective interest rates as determined at the closing of the loan. Interest income recorded on these commercial mortgage loans was $5.7 million, $6.9 million and $8.6 million for the years ended December 31, 2013, 2012 and 2011, respectively.
The fair value and aggregate unpaid principal amounts of obligations for which the fair value option has been elected were $104.9 million and $174.4 million as of December 31, 2013, and $85.0 million and $186.8 million as of December 31, 2012, respectively. For the years ended December 31, 2013, 2012 and 2011, the change in fair value of the obligations resulted in a pre-tax gain (loss) of ($32.8) million, ($37.7) million and $1.2 million, which includes a pre-tax loss of $34.3 million, $37.4 million and $1.1 million related to instrument-specific credit risk that is estimated based on credit spreads and quality ratings, respectively. Interest expense recorded on these obligations is included in operating expenses on the consolidated statements of operations and was $3.6 million, $5.3 million and $6.7 million for the years ended December 31, 2013, 2012 and 2011, respectively.
We invest in real estate ventures for the purpose of earning investment returns and for capital appreciation. We elected the fair value option for certain ventures that are subject to the equity method of accounting because the nature of the investments are to add value to the properties and generate income from the operations of the properties. Other equity method real estate investments are not fair valued because the investments mainly generate income from the operations of the underlying properties. These investments are reported with other investments in the consolidated statements of financial position. The changes in fair value are reported in net investment income on the consolidated statements of operations. The fair value of the equity method investments for which the fair value option has been elected was $74.8 million and $33.6 million as of December 31, 2013 and 2012, respectively. The change in fair value of the investments resulted in an $11.0 million and $(0.4) million pre-tax gain (loss) for the years ended December 31, 2013 and 2012, respectively.
Financial Instruments Not Reported at Fair Value
The carrying value and estimated fair value of financial instruments not recorded at fair value on a recurring basis but required to be disclosed at fair value were as follows:
	December 31, 2013
							Fair value hierarchy level
	Carrying amount
				Fair value			Level 1			Level 2			Level 3
	(in millions)
Assets (liabilities)
Mortgage loans	$	11,533.60		$	11,773.50		$	—		$	—		$	11,773.50
Policy loans		859.7			963.3			—			—			963.3
Other investments		174			174.7			—			140.9			33.8
Cash and cash equivalents		912.8			912.8			912.8			—			—
Investments-type insurance contracts		(29,909.6	)		(30,093.1	)		—			(5,902.2	)		(24,190.9	)
Short-term debt		(150.6	)		(150.6	)		—			(150.6	)		—
Long-term debt		(2,601.4	)		(2,692.1	)		—			(2,639.0	)		(53.1	)
Separate account liabilities		(119,500.7	)		(118,059.7	)		—			—			(118,059.7	)
Bank deposits		(1,949.0	)		(1,951.1	)		(1,252.2	)		(698.9	)		—
Cash collateral payable		(32.5	)		(32.5	)		(32.5	)		—			—
	December 31, 2012
							Fair value hierarchy level
	Carrying amount
				Fair value			Level 1			Level 2			Level 3
	(in millions)
Assets (liabilities)
Mortgage loans	$	11,519.70		$	12,163.70		$	—		$	—		$	12,163.70
Policy loans		864.9			1,056.80			—			—			1,056.80
Other investments		280.1			280.5			—			195.3			85.2
Cash and cash equivalents		2,404.60			2,404.60			2,364.60			40			—
Investments-type insurance contracts		(31,953.1	)		(32,531.6	)		—			(7,367.4	)		(25,164.2	)
Short-term debt		(40.8	)		(40.8	)		—			(40.8	)		—
Long-term debt		(2,671.3	)		(2,951.4	)		—			(2,921.7	)		(29.7	)
Separate account liabilities		(73,096.0	)		(72,173.8	)		—			—			(72,173.8	)
Bank deposits		(2,174.7	)		(2,177.7	)		(1,404.4	)		(773.3	)		—
Cash collateral payable		(205.6	)		(205.6	)		(205.6	)		—			—
Mortgage Loans
Fair values of commercial and residential mortgage loans are primarily determined by discounting the expected cash flows at current treasury rates plus an applicable risk spread, which reflects credit quality and maturity of the loans. The risk spread is based on market clearing levels for loans with comparable credit quality, maturities and risk. The fair value of mortgage loans may also be based on the fair value of the underlying real estate collateral less cost to sell, which is estimated using appraised values. These are reflected in Level 3.
Policy Loans
Fair values of policy loans are estimated by discounting expected cash flows using a risk-free rate based on the Treasury curve. The expected cash flows reflect an estimate of timing of the repayment of the loans. These are reflected in Level 3.
Other Investments
The fair value of commercial loans and certain consumer loans included in other investments is calculated by discounting scheduled cash flows through the estimated maturity date using market interest rates that reflect the credit and interest rate risk inherent in the loans. The estimate of term to maturity is based on historical experience, adjusted as required, for current economic and lending conditions. The effect of nonperforming loans is considered in assessing the credit risk inherent in the fair value estimate. These are reflected in Level 3. The carrying value of the remaining investments reported in this line item approximate their fair value and are of a short-term nature. These are reflected in Level 2.
Cash and Cash Equivalents
Certain cash equivalents not reported at fair value include short-term investments with maturities of less than three months for which public quotations are not available to use in determining fair value. Because of the highly liquid nature of these assets, carrying amounts are used to approximate fair value, which are reflected in Level 2. The carrying amounts of the remaining cash and cash equivalents that are not reported at fair value on a recurring basis approximate their fair value, which are reflected in Level 1 given the nature of cash.
Investment-Type Insurance Contracts
The fair values of our reserves and liabilities for investment-type insurance contracts are determined via a third party pricing vendor or using discounted cash flow analyses when we are unable to find a price from third party pricing vendors. Third party pricing on various outstanding medium-term notes and funding agreements is based on observable inputs such as benchmark yields and spreads based on reported trades for our medium-term notes and funding agreement issuances. These are reflected in Level 2. The discounted cash flow analyses for the remaining contracts is based on current interest rates, including non-performance risk, being offered for similar contracts with maturities consistent with those remaining for the investment-type contracts being valued. These are reflected in Level 3. Investment-type insurance contracts include insurance, annuity and other policy contracts that do not involve significant mortality or morbidity risk and are only a portion of the policyholder liabilities appearing in the consolidated statements of financial position. Insurance contracts include insurance, annuity and other policy contracts that do involve significant mortality or morbidity risk. The fair values for our insurance contracts, other than investment-type contracts, are not required to be disclosed.
Short-Term Debt
The carrying amount of short-term debt approximates its fair value because of the relatively short time between origination of the debt instrument and its maturity, which is reflected in Level 2.
Long-Term Debt
Long-term debt primarily includes senior note issuances for which the fair values are determined using inputs that are observable in the market or that can be derived from or corroborated with observable market data. These are reflected in Level 2. Additionally, our long-term debt includes non-recourse mortgages and notes payable that are primarily financings for real estate developments for which the fair values are estimated using discounted cash flow analysis based on our incremental borrowing rate for similar borrowing arrangements. These are reflected in Level 3.
Separate Account Liabilities
Fair values of separate account liabilities, excluding insurance-related elements, are estimated based on market assumptions around what a potential acquirer would pay for the associated block of business, including both the separate account assets and liabilities. As the applicable separate account assets are already reflected at fair value, any adjustment to the fair value of the block is an assumed adjustment to the separate account liabilities. To compute fair value, the separate account liabilities are originally set to equal separate account assets because these are pass-through contracts. The separate account liabilities are reduced by the amount of future fees expected to be collected that are intended to offset upfront acquisition costs already incurred that a potential acquirer would not have to pay. The estimated future fees are adjusted by an adverse deviation discount and the amount is then discounted at a risk-free rate as measured by the yield on Treasury securities at maturities aligned with the estimated timing of fee collection. These are reflected in Level 3.
Bank Deposits
The fair value of deposits of our Principal Bank subsidiary with no stated maturity is equal to the amount payable on demand (i.e., their carrying amounts). These are reflected in Level 1. The fair value of certificates of deposit is based on the discounted value of contractual cash flows. The discount is estimated using the rates currently offered for deposits of similar remaining maturities. These are reflected in Level 2.
Cash Collateral Payable
The carrying amount of the payable associated with our obligation to return the cash collateral received under derivative credit support annex (collateral) agreements approximates its fair value, which is reflected in Level 1.

Statutory_Insurance_Financial_

Statutory Insurance Financial Information	12 Months Ended
	Dec. 31, 2013
Statutory Insurance Financial Information	'
Statutory Insurance Financial Information	'
	16. 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 "State of Iowa"). The State of Iowa 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. As of December 31, 2013, our use of prescribed and permitted statutory accounting practices has resulted in higher statutory net income of $9.0 million relative to the accounting practices and procedures of the NAIC due to our accounting for derivatives that hedge some of our equity indexed products. 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.
	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, 2013, our affiliated reinsurance subsidiaries assumed statutory reserves of $2,765.7 million from Principal Life. 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, 2013, assets admitted under these practices totaled $1,059.0 million.
	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. At December 31, 2013, Principal Life meets 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,
		2013		2012		2011
		(in millions)
	Statutory net income	$	607.9	$	576.1	$	326.8
	Statutory capital and surplus		4,142.20		3,944.30		4,218.20

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2013
Segment Information	'
Segment Information	'
	17. Segment Information
	We provide financial products and services through the following segments: Retirement and Investor Services, Principal Global Investors, Principal International and U.S. Insurance Solutions. In addition, there is 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 Investor Services segment provides retirement and related financial products and services primarily to businesses, their employees and other individuals.
	The Principal Global Investors segment provides asset management services to our asset accumulation business, our insurance operations, the Corporate segment and third-party clients.
	The Principal International segment has operations in Brazil, Chile, China, Hong Kong Special Administrative Region, India, Mexico and Southeast Asia. We focus on countries with large middle classes, favorable demographics and growing long-term savings, ideally with defined contribution markets. We entered these countries through acquisitions, start-up operations and joint ventures.
	The U.S. Insurance Solutions segment provides individual life insurance and specialty benefits, which consists of group dental and vision insurance, individual and group disability insurance, group life insurance and non-medical fee-for-service claims administration, throughout the United States.
	The 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 interest expense and preferred stock dividends), income on capital not allocated to other segments, inter-segment eliminations, U.S. income tax risks and certain income, expenses and other after-tax adjustments not allocated to the segments based on the nature of such items. Results of our exited group medical insurance business are reported in this segment.
	Management uses segment operating earnings in goal setting, as a basis for determining employee compensation and in evaluating performance on a basis comparable to that used by securities analysts. We determine segment operating earnings by adjusting U.S. GAAP net income for net realized capital gains (losses), as adjusted, and other after-tax adjustments which management believes are not indicative of overall operating trends. Net realized capital gains (losses), as adjusted, are net of income taxes, related changes in the amortization pattern of DAC and other actuarial balances, recognition of deferred front-end fee revenues for sales charges on retirement and life insurance products and services, amortization of hedge accounting book value adjustments for certain discontinued hedges, net realized capital gains and losses distributed, noncontrolling interest capital gains and losses and certain market value adjustments to fee revenues. Net realized capital gains (losses), as adjusted, exclude periodic settlements and accruals on derivative instruments not designated as hedging instruments and exclude certain market value adjustments of embedded derivatives and realized capital gains (losses) associated with our exited group medical insurance business. Segment operating revenues exclude net realized capital gains (losses) (except periodic settlements and accruals on derivatives not designated as hedging instruments), including their impact on recognition of front-end fee revenues, certain market value adjustments to fee revenues and amortization of hedge accounting book value adjustments for certain discontinued hedges, and revenue from our exited group medical insurance business. Segment operating revenues include operating revenues from real estate properties that qualify for discontinued operations. While these items may be significant components in understanding and assessing the consolidated financial performance, management believes the presentation of segment operating earnings enhances the understanding of our results of operations by highlighting earnings attributable to the normal, ongoing operations of the business.
	The accounting policies of the segments are consistent with the accounting policies for the consolidated financial statements, with the exception of income tax allocation. The Corporate segment functions to absorb the risk inherent in interpreting and applying tax law. The segments are allocated tax adjustments consistent with the positions we took on tax returns. The Corporate segment results reflect any differences between the U.S. tax returns and the estimated resolution of any disputes.
	The following tables summarize select financial information by segment and reconcile segment totals to those reported in the consolidated financial statements:
		December 31, 2013			December 31, 2012
		(in millions)
	Assets:
	Retirement and Investor Services	$	128,736.70		$	117,399.50
	Principal Global Investors		1,312.10			1,282.20
	Principal International		54,243.60			19,170.90
	U.S. Insurance Solutions		20,033.60			19,017.20
	Corporate		3,865.40			4,960.40
	Total consolidated assets	$	208,191.40		$	161,830.20
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Operating revenues by segment:
	Retirement and Investor Services	$	4,847.60		$	4,834.90		$	4,075.00
	Principal Global Investors		719.2			591.2			546.3
	Principal International		1,150.00			942.7			909
	U.S. Insurance Solutions		3,106.40			2,994.70			2,939.90
	Corporate		(215.8	)		(188.1	)		(189.2	)
	Total segment operating revenues		9,607.40			9,175.40			8,281.00
	Net realized capital gains (losses), net of related revenue adjustments		(320.0	)		14.7			(221.5	)
	Exited group medical insurance business		2.1			25			606.3
	Assumption change within our Individual Life business		—			—			4.9
	Total revenues per consolidated statements of operations	$	9,289.50		$	9,215.10		$	8,670.70
	Operating earnings (loss) by segment, net of related income taxes:
	Retirement and Investor Services	$	694.4		$	575.1		$	562.9
	Principal Global Investors		102.6			81.2			74
	Principal International		215.2			154.1			135
	U.S. Insurance Solutions		196.6			138.2			204.3
	Corporate		(148.9	)		(139.8	)		(146.9	)
	Total segment operating earnings, net of related income taxes		1,059.90			808.8			829.3
	Net realized capital gains (losses), as adjusted (1)		(179.1	)		39			(141.7	)
	Other after-tax adjustments (2)		(1.1	)		(74.2	)		(82.3	)
	Net income available to common stockholders per consolidated statements of operations	$	879.7		$	773.6		$	605.3
	-1
	Net realized capital gains (losses), as adjusted, is derived as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Net realized capital gains (losses):
	Net realized capital gains (losses)	$	(225.2	)	$	114.1		$	(122.3	)
	Certain derivative and hedging-related adjustments		(93.9	)		(98.9	)		(98.8	)
	Certain market value adjustments to fee revenues		—			(0.3	)		(0.1	)
	Recognition of front-end fee revenue		(0.9	)		(0.2	)		(0.3	)
	Net realized capital gains (losses), net of related revenue adjustments		(320.0	)		14.7			(221.5	)
	Amortization of deferred acquisition costs and other actuarial balances		47.1			36.6			(21.5	)
	Capital gains distributed		(25.8	)		(12.2	)		(3.1	)
	Certain market value adjustments of embedded derivatives		18.4			(0.6	)		65.6
	Net realized capital (gains) losses associated with exited group medical insurance business		—			0.2			(0.2	)
	Noncontrolling interest capital gains		(0.2	)		(8.3	)		(31.6	)
	Income tax effect		101.4			8.6			70.6
	Net realized capital gains (losses), as adjusted	$	(179.1	)	$	39		$	(141.7	)
-2
For the year ended December 31, 2013, other after-tax adjustments included the negative effect of losses associated with our exited group medical insurance business that does not qualify for discontinued operations accounting treatment under U.S. GAAP.
For the year ended December 31, 2012, other after-tax adjustments included the negative effect of (a) a contribution made to The Principal Financial Group Foundation, Inc. ($39.8 million), (b) one-time costs incurred to extinguish long-term debt that was scheduled to mature in 2014 ($24.8 million) and (c) losses associated with our exited group medical insurance business that does not qualify for discontinued operations accounting treatment under U.S. GAAP ($9.6 million).
For the year ended December 31, 2011, other after-tax adjustments included (1) the negative effect resulting from (a) the impact of a court ruling on some uncertain tax positions ($68.9 million), (b) an assumption change in our Individual Life business ($34.5 million), (c) a contribution made to The Principal Financial Group Foundation, Inc. ($19.5 million) and (d) our estimated obligation associated with Executive Life of New York's liquidation petition ($10.3 million) and (2) the positive effect of gains associated with our exited group medical insurance business that does not qualify for discontinued operations accounting treatment under U.S. GAAP ($50.9 million).
The following is a summary of income tax expense (benefit) allocated to our segments for purposes of determining operating earnings. Segment income taxes are reconciled to income taxes reported on our consolidated statements of operations.
	For the year ended
	December 31,
	2013			2012			2011
	(in millions)
Income tax expense by segment:
Retirement and Investor Services	$	195.6		$	150		$	163.9
Principal Global Investors		55.5			43.5			41
Principal International		28			0.6			(3.1	)
U.S. Insurance Solutions		94			61.3			95.3
Corporate		(83.2	)		(69.6	)		(72.9	)
Total segment income taxes from operating earnings		289.9			185.8			224.2
Tax benefit related to net realized capital losses, as adjusted		(101.4	)		(8.6	)		(70.6	)
Tax expense (benefit) related to other after-tax adjustments		(0.6	)		(42.6	)		44.7
Total income taxes expense per consolidated statements of operations	$	187.9		$	134.6		$	198.3
The following is a summary of depreciation and amortization expense allocated to our segments for purposes of determining operating earnings. Segment depreciation and amortization equates to depreciation and amortization included in our consolidated statements of operations.
	For the year ended
	December 31,
	2013			2012			2011
	(in millions)
Depreciation and amortization expense by segment:
Retirement and Investor Services	$	26.7		$	26.3		$	24.7
Principal Global Investors		11.8			13.3			11.3
Principal International		47.8			18.9			14.8
U.S. Insurance Solutions		17.2			17			16.6
Corporate		4.6			5.4			5
Total segment depreciation and amortization expense included in operating earnings		108.1			80.9			72.4
Depreciation and amortization expense related to other after-tax adjustments		1.4			6.1			6.1
Total depreciation and amortization expense included in our consolidated statements of operations	$	109.5		$	87		$	78.5
The following table summarizes operating revenues for our products and services:
	For the year ended
	December 31,
	2013			2012			2011
	(in millions)
Retirement and Investor Services:
Full service accumulation	$	1,470.70		$	1,357.00		$	1,338.00
Principal Funds		765.8			619.6			560.4
Individual annuities		1,366.50			1,162.40			1,119.20
Bank and trust services		95.2			101.6			100.5
Eliminations		(146.8	)		(120.3	)		(111.8	)
Total Accumulation		3,551.40			3,120.30			3,006.30
Investment only		341			431.6			508
Full service payout		955.2			1,283.00			560.7
Total Guaranteed		1,296.20			1,714.60			1,068.70
Total Retirement and Investor Services		4,847.60			4,834.90			4,075.00
Principal Global Investors (1)		719.2			591.2			546.3
Principal International		1,150.00			942.7			909
U.S. Insurance Solutions:
Individual life insurance		1,483.00			1,423.30			1,432.00
Specialty benefits insurance		1,623.60			1,571.40			1,507.90
Eliminations		(0.2	)		—			—
Total U.S. Insurance Solutions		3,106.40			2,994.70			2,939.90
Corporate		(215.8	)		(188.1	)		(189.2	)
Total operating revenues	$	9,607.40		$	9,175.40		$	8,281.00
Total operating revenues	$	9,607.40		$	9,175.40		$	8,281.00
Net realized capital gains (losses), net of related revenue adjustments		(320.0	)		14.7			(221.5	)
Exited group medical insurance business		2.1			25			606.3
Assumption change within our Individual Life business		—			—			4.9
Total revenues per consolidated statements of operations	$	9,289.50		$	9,215.10		$	8,670.70
-1
Reflects inter-segment revenues of $243.7 million, $217.6 million and $212.2 million for the years ended December 31, 2013, 2012 and 2011, respectively.

StockBased_Compensation_Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2013
Stock-Based Compensation Plans	'
Stock-Based Compensation Plans	'
	18. Stock-Based Compensation Plans
	As of December 31, 2013, we have the Amended and Restated 2010 Stock Incentive Plan, the Employee Stock Purchase Plan, the 2005 Directors Stock Plan, the Stock Incentive Plan, the Directors Stock Plan and the Long-Term Performance Plan ("Stock-Based Compensation Plans"). As of May 17, 2005, no new grants will be made under the Stock Incentive Plan, the Directors Stock Plan or the Long-Term Performance Plan. Under the terms of the Amended and Restated 2010 Stock Incentive Plan, grants may be nonqualified stock options, incentive stock options qualifying under Section 422 of the Internal Revenue Code, restricted stock, restricted stock units, stock appreciation rights, performance shares, performance units or other stock-based awards. The 2005 Directors Stock Plan provides for the grant of nonqualified stock options, restricted stock, restricted stock units or other stock-based awards to our nonemployee directors. To date, we have not granted any incentive stock options, restricted stock or performance units.
	As of December 31, 2013, the maximum number of new shares of common stock that were available for grant under the Amended and Restated 2010 Stock Incentive Plan and the 2005 Directors Stock Plan was 6.5 million.
	For awards with graded vesting, we use an accelerated expense attribution method. The compensation cost that was charged against income for stock-based awards granted under the Stock-Based Compensation Plans was as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Compensation cost	$	65.2		$	53.7		$	46.3
	Related income tax benefit		20			17.7			15.8
	Capitalized as part of an asset		2.6			2.3			2.2
	Nonqualified Stock Options
	Nonqualified stock options were granted to certain employees under the Amended and Restated 2010 Stock Incentive Plan and the Stock Incentive Plan. Options outstanding under the Amended and Restated 2010 Stock Incentive Plan and the Stock Incentive Plan 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 period, except in the case of approved retirement. Total options granted under the Amended and Restated 2010 Stock Incentive Plan were 0.8 million, 0.8 million and 0.5 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	Nonqualified stock options granted under the Directors Stock Plan have an exercise price equal to the fair market value of our common stock on the date of the grant and a contractual term equal to the earlier of five years from the date the participant ceases to provide service or the tenth anniversary of the date the option was granted. Beginning with the 2003 grant, options become exercisable in four approximately equal installments on the three, six and nine month anniversaries of the grant date, and on the date that the Director's full term of office expires. There were no options granted during the years ended December 31, 2013, 2012 and 2011.
	The following is a summary of the status of all of our stock option plans:
		Number of options			Weighted-			Intrinsic value
					average
					exercise price
		(in millions)						(in millions)
	Options outstanding at January 1, 2013		12.2		$	39.61
	Granted		0.8			30.7
	Exercised		3.3			32.03
	Expired		0.1			44.75
	Options outstanding at December 31, 2013		9.6		$	41.37		$	112.2
	Options vested or expected to vest at December 31, 2013		9.6		$	41.39		$	112
	Options exercisable at December 31, 2013		8.1		$	43.47		$	83.3
	The total intrinsic value of stock options exercised was $30.7 million, $5.7 million and $4.0 million during 2013, 2012, and 2011, 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, 2013:
	Range of exercise prices	Number of options			Weighted-
		outstanding			average remaining
					contractual life
		(in millions)
	$11.07 - $21.69		1.1			5.2
	$21.70 - $32.32		2.3			8
	$32.33 - $42.95		1.5			3
	$42.96 - $53.58		1.7			2.2
	$53.59 - $64.22		3			3.7
	$11.07 - $64.22		9.6			4.5
	The weighted-average remaining contractual lives for stock options exercisable is approximately 3.7 years as of December 31, 2013.
	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	2013			2012			2011
	Expected volatility		53.3	%		70	%		67.9	%
	Expected term (in years)		6.5			6			6
	Risk-free interest rate		1.1	%		1.1	%		2.5	%
	Expected dividend yield		3	%		2.55	%		1.6	%
	Weighted average estimated fair value	$	11.95		$	13.95		$	18.82
	We previously determined expected volatility based on, among other factors, historical volatility using daily price observations. Beginning with nonqualified stock options granted in 2013, 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, 2013, there was $2.7 million of total unrecognized compensation costs related to nonvested stock options. The cost is expected to be recognized over a weighted-average service period of approximately 1.6 years.
	Cash received from stock options exercised under these share-based payment arrangements during 2013, 2012 and 2011 was $105.6 million, $11.3 million and $7.3 million, respectively. The actual tax benefits realized for the tax deductions for options exercised under these share-based payment arrangements during 2013, 2012 and 2011 was $10.6 million, $1.6 million and $1.4 million, respectively.
	Performance Share Awards
	We granted performance share awards to certain employees under 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 an approved retirement) and our performance against three-year goals set at the beginning of the performance period. Performance goals based on various factors, including return on equity, operating income and book value per share, must be achieved for any of the performance shares to be earned. If the performance requirements are not met, the performance shares will be forfeited, no compensation cost is recognized and any previously recognized compensation cost is reversed. There is no maximum contractual term on these awards. Dividend equivalents are credited on performance shares outstanding as of the record date. These dividend equivalents are only paid on the shares released. Total performance share awards granted were 0.3 million, 0.4 million and 0.3 million in 2013, 2012 and 2011, respectively.
	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 at January 1, 2013		1		$	27.28
	Granted		0.3			30.7
	Vested		0.3			22.21
	Nonvested performance share awards at December 31, 2013		1		$	30.3
	The total intrinsic value of performance share awards vested was $10.9 million, $13.0 million and zero during 2013, 2012 and 2011, respectively.
Performance share awards above represent initial target awards and do not reflect potential increases or decreases resulting from the final performance objectives to be determined at the end of the respective performance period. The actual number of 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 2013, 2012 and 2011 were $30.70, $27.46 and $34.26, respectively.
As of December 31, 2013, there was $5.2 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 1.5 years.
Actual tax benefits realized for the tax deductions for performance share awards paid out under these share based payment arrangements for 2013, 2012 and 2011 was $4.7 million, $4.7 million and zero, respectively.
Restricted Stock Units
We issue restricted stock units under the Amended and Restated 2010 Stock Incentive Plan, 2005 Directors Stock Plan, Stock Incentive Plan, and Directors Stock Plan. Restricted stock units are treated as an equity award and are paid in shares. There is no maximum contractual term on these awards. Dividend equivalents are credited on restricted stock units outstanding as of the record date. These dividend equivalents are only paid on the shares released. In 2013, 2012 and 2011, 1.3 million, 1.2 million and 0.9 million restricted stock units were granted, respectively.
Restricted stock units were issued to certain employees and agents pursuant to the Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan. Under these plans, awards have graded or cliff vesting over a three-year service period. When service for PFG ceases (except in the case of an approved retirement), all vesting stops and unvested units are forfeited.
Pursuant to 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 the 2005 Directors Stock Plan, awards are granted on an annual basis and cliff vest after a one-year service period. When service to PFG ceases, all vesting stops and unvested units are forfeited.
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 at January 1, 2013		3.1		$	27.3
Granted		1.3			31.02
Vested		1.2			22.73
Canceled		0.1			30.37
Nonvested restricted stock units at December 31, 2013		3.1		$	30.46
The total intrinsic value of restricted stock units vested was $37.7 million, $31.9 million and $19.9 million during 2013, 2012 and 2011, 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 2013, 2012 and 2011 was $31.02, $27.33 and $33.35, respectively.
As of December 31, 2013, there was $36.6 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 1.8 years.
The actual tax benefits realized for the tax deductions for restricted stock unit payouts under these share-based payment arrangements for 2013, 2012 and 2011 was $11.5 million, $11.1 million and $7.3 million, respectively.
Employee Stock Purchase Plan
Under our Employee Stock Purchase Plan, participating employees have the opportunity to purchase shares of our common stock on a semi-annual basis. Employees may purchase up to $25,000 worth of company stock each year. 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 0.8 million, 0.9 million and 0.7 million shares during 2013, 2012 and 2011, 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 $14.20, $5.34 and $4.20 during 2013, 2012 and 2011, respectively. The total intrinsic value of the Employee Stock Purchase Plan shares settled was $11.4 million, $4.6 million and $3.1 million during 2013, 2012 and 2011, respectively.
Cash received from shares issued under these share-based payment arrangements for 2013, 2012 and 2011 was $20.4 million, $17.8 million and $18.7 million, respectively. The actual tax benefits realized for the tax deductions for the settlement of the share-based payment arrangements for 2013, 2012 and 2011 was $1.1 million, $0.5 million and $0.7 million, respectively.
As of December 31, 2013, a total of 5.2 million of new shares are available to be made issuable by us for this plan.

Earnings_Per_Common_Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2013
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,
		2013		2012		2011
		(in millions, except per
		share data)
	Net income	$	936.1	$	825.4	$	674.5
	Subtract:
	Net income attributable to noncontrolling interest		23.4		18.8		36.2
	Preferred stock dividends		33		33		33
	Adjustments to redemption amounts of redeemable noncontrolling interests (1)		—		—		—
	Net income available to common stockholders	$	879.7	$	773.6	$	605.3
	Weighted-average shares outstanding:
	Basic		294.6		297.5		314.5
	Dilutive effects:
	Stock options		1.6		1		1.2
	Restricted stock units		1.7		1.5		1.5
	Performance share awards		0.3		0.4		0.4
	Diluted		298.2		300.4		317.6
	Net income per common share:
	Basic	$	2.99	$	2.6	$	1.92
	Diluted	$	2.95	$	2.58	$	1.91
	-1
	During the third quarter of 2013, we identified a classification error of certain of our noncontrolling interests, which had a related impact to earnings per share. See related discussion in Note 14, Stockholders' Equity — Noncontrolling Interest. The correction of the classification error in the third quarter of 2013 did not significantly impact earnings per share.
	The calculation of diluted earnings per share for the years ended December 31, 2013, 2012 and 2011, excludes the incremental effect related to certain outstanding stock-based compensation grants due to their anti-dilutive effect.

Quarterly_Results_of_Operation

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2013
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)
	2013
	Total revenues	$	2,672.60	$	2,239.60	$	2,210.60	$	2,166.70
	Total expenses		2,362.70		1,919.30		1,945.00		1,938.50
	Net income		250.4		259.1		236.6		190
	Net income available to common stockholders		233.4		245.7		222.3		178.3
	Basic earnings per common share for net income available to common stockholders		0.79		0.83		0.76		0.61
	Diluted earnings per common share for net income available to common stockholders		0.78		0.82		0.75		0.61
	2012
	Total revenues	$	2,295.90	$	2,704.70	$	2,118.60	$	2,095.90
	Total expenses		2,035.00		2,513.10		1,889.10		1,817.90
	Net income		226.7		198.8		178.6		221.3
	Net income available to common stockholders		214.9		187.2		167.6		203.9
	Basic earnings per common share for net income available to common stockholders		0.72		0.64		0.56		0.68
	Diluted earnings per common share for net income available to common stockholders		0.72		0.63		0.56		0.68

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information	12 Months Ended
	Dec. 31, 2013
Condensed Consolidating Financial Information	'
Condensed Consolidating Financial Information	'
	21. Condensed Consolidating Financial Information
	Principal Life has established special purpose entities to issue secured medium-term notes. Under the program, the payment obligations of principal and interest on the notes are secured by funding agreements issued by Principal Life. Principal Life's payment obligations on the funding agreements are fully and unconditionally guaranteed by PFG. All of the outstanding stock of Principal Life is indirectly owned by PFG and PFG is the only guarantor of the payment obligations of the funding agreements.
	The following tables set forth condensed consolidating financial information of (i) PFG, (ii) Principal Life, (iii) Principal Financial Services, Inc. ("PFS") 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, 2013 and December 31, 2012, and for the years ended December 31, 2013, 2012 and 2011.
	In presenting the condensed consolidating financial statements, the equity method of accounting has been applied to (i) PFG's interest in PFS, (ii) Principal Life's interest in all direct subsidiaries of Principal Life and (iii) PFS's interest in Principal Life 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, Principal Life and PFS 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.
	Condensed Consolidating Statements of Financial Position
	December 31, 2013
		Principal			Principal Life			Principal Financial			Eliminations			Principal
		Financial			Insurance			Services, Inc. and						Financial
		Group, Inc.			Company			Other Subsidiaries						Group, Inc.
		Parent Only			Only			Combined						Consolidated
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	—		$	42,794.70		$	6,357.50		$	(395.1	)	$	48,757.10
	Fixed maturities, trading		—			245.5			317.6			—			563.1
	Equity securities, available-for-sale		—			102.6			7.9			—			110.5
	Equity securities, trading		—			0.3			716.6			—			716.9
	Mortgage loans		—			10,501.50			1,345.90			(313.8	)		11,533.60
	Real estate		—			7.9			1,263.70			—			1,271.60
	Policy loans		—			830.1			29.6			—			859.7
	Investment in unconsolidated entities		11,956.20			3,396.80			4,891.60			(19,364.6	)		880
	Other investments		9.3			1,892.40			1,238.80			(1,076.1	)		2,064.40
	Cash and cash equivalents		131.5			1,332.20			894.5			13.6			2,371.80
	Accrued investment income		—			474.5			59			(1.4	)		532.1
	Premiums due and other receivables		—			1,029.00			1,814.50			(1,602.5	)		1,241.00
	Deferred acquisition costs		—			2,848.80			228.2			—			3,077.00
	Property and equipment		—			422.1			78.6			—			500.7
	Goodwill		—			54.3			1,046.00			—			1,100.30
	Other intangibles		—			26.9			1,432.10			—			1,459.00
	Separate account assets		—			83,790.20			46,228.20			—			130,018.40
	Other assets		59.2			976.9			2,115.30			(2,017.2	)		1,134.20
	Total assets	$	12,156.20		$	150,726.70		$	70,065.60		$	(24,757.1	)	$	208,191.40
	Liabilities
	Contractholder funds	$	—		$	34,918.00		$	1,330.70		$	(290.4	)	$	35,958.30
	Future policy benefits and claims		—			18,292.90			4,625.00			(291.7	)		22,626.20
	Other policyholder funds		—			705.1			54.2			(0.4	)		758.9
	Short-term debt		—			—			150.6			—			150.6
	Long-term debt		2,448.80			99.4			367			(313.8	)		2,601.40
	Income taxes currently payable		—			—			67.4			(62.2	)		5.2
	Deferred income taxes		—			(25.0	)		1,030.10			(181.1	)		824
	Separate account liabilities		—			83,790.20			46,228.20			—			130,018.40
	Other liabilities		23.2			5,204.80			3,911.80			(3,915.6	)		5,224.20
	Total liabilities		2,472.00			142,985.40			57,765.00			(5,055.2	)		198,167.20
	Redeemable noncontrolling interest		—			—			247.2			—			247.2
	Stockholders' equity
	Series A preferred stock		—			—			—			—			—
	Series B preferred stock		0.1			—			—			—			0.1
	Common stock		4.6			2.5			—			(2.5	)		4.6
	Additional paid-in capital		9,798.90			5,505.00			9,163.70			(14,668.7	)		9,798.90
	Retained earnings		5,405.40			1,738.10			2,578.20			(4,316.3	)		5,405.40
	Accumulated other comprehensive income		183.2			495.7			214.3			(710.0	)		183.2
	Treasury stock, at cost		(5,708.0	)		—			—			—			(5,708.0	)
	Total stockholders' equity attributable to PFG		9,684.20			7,741.30			11,956.20			(19,697.5	)		9,684.20
	Noncontrolling interest		—			—			97.2			(4.4	)		92.8
	Total stockholders' equity		9,684.20			7,741.30			12,053.40			(19,701.9	)		9,777.00
	Total liabilities and stockholders' equity	$	12,156.20		$	150,726.70		$	70,065.60		$	(24,757.1	)	$	208,191.40
	Condensed Consolidating Statements of Financial Position
	December 31, 2012
		Principal			Principal Life			Principal Financial			Eliminations			Principal
		Financial			Insurance			Services, Inc. and						Financial
		Group, Inc.			Company			Other Subsidiaries						Group, Inc.
		Parent Only			Only			Combined						Consolidated
		(in millions)
	Assets
Fixed maturities, available-for-sale	$	—		$	44,614.60		$	6,681.70		$	(357.0	)	$	50,939.30
Fixed maturities, trading		10.5			284.4			331.8			—			626.7
Equity securities, available-for-sale		—			131.3			5.2			—			136.5
Equity securities, trading		—			0.3			252.5			—			252.8
Mortgage loans		—			10,054.20			1,775.50			(310.0	)		11,519.70
Real estate		—			8.4			1,171.90			—			1,180.30
Policy loans		—			834			30.9			—			864.9
Investment in unconsolidated entities		11,853.30			3,309.20			4,808.30			(19,101.8	)		869
Other investments		11.1			2,834.00			1,208.40			(1,631.4	)		2,422.10
Cash and cash equivalents		207.1			1,698.40			2,286.90			(15.2	)		4,177.20
Accrued investment income		—			521.6			64.5			(1.7	)		584.4
Premiums due and other receivables		0.1			916.7			1,327.10			(1,159.5	)		1,084.40
Deferred acquisition costs		—			2,394.80			195.2			—			2,590.00
Property and equipment		—			402.2			62			—			464.2
Goodwill		—			54.3			489.1			—			543.4
Other intangibles		—			27.9			886.8			—			914.7
Separate account assets		—			69,217.80			12,436.00			—			81,653.80
Other assets		78			947.8			1,567.70			(1,586.7	)		1,006.80
Total assets	$	12,160.10		$	138,251.90		$	35,581.50		$	(24,163.3	)	$	161,830.20
Liabilities
Contractholder funds	$	—		$	37,053.30		$	1,011.90		$	(278.7	)	$	37,786.50
Future policy benefits and claims		—			17,944.90			4,679.60			(188.3	)		22,436.20
Other policyholder funds		—			676.5			40.3			(0.4	)		716.4
Short-term debt		—			—			40.8			—			40.8
Long-term debt		2,448.60			99.4			433.3			(310.0	)		2,671.30
Income taxes currently payable		—			—			84.7			(69.4	)		15.3
Deferred income taxes		—			324.5			378.4			(102.9	)		600
Separate account liabilities		—			69,217.80			12,436.00			—			81,653.80
Other liabilities		28.1			5,375.10			4,538.40			(3,795.5	)		6,146.10
Total liabilities		2,476.70			130,691.50			23,643.40			(4,745.2	)		152,066.40
Redeemable noncontrolling interest		—			—			60.4			—			60.4
Stockholders' equity
Series A preferred stock		—			—			—			—			—
Series B preferred stock		0.1			—			—			—			0.1
Common stock		4.5			2.5			—			(2.5	)		4.5
Additional paid-in capital		9,730.90			5,747.60			9,393.80			(15,141.4	)		9,730.90
Retained earnings		4,862.00			1,167.70			1,783.40			(2,951.1	)		4,862.00
Accumulated other comprehensive income		640.3			642.6			676.1			(1,318.7	)		640.3
Treasury stock, at cost		(5,554.4	)		—			—			—			(5,554.4	)
Total stockholders' equity attributable to PFG		9,683.40			7,560.40			11,853.30			(19,413.7	)		9,683.40
Noncontrolling interest		—			—			24.4			(4.4	)		20
Total stockholders' equity		9,683.40			7,560.40			11,877.70			(19,418.1	)		9,703.40
Total liabilities and stockholders' equity	$	12,160.10		$	138,251.90		$	35,581.50		$	(24,163.3	)	$	161,830.20
Condensed Consolidating Statements of Operations
For the year ended December 31, 2013
	Principal			Principal Life			Principal Financial			Eliminations			Principal
	Financial			Insurance			Services, Inc. and						Financial
	Group, Inc.			Company			Other Subsidiaries						Group, Inc.
	Parent Only			Only			Combined						Consolidated
	(in millions)
Revenues
Premiums and other considerations	$	—		$	2,788.10		$	366		$	—		$	3,154.10
Fees and other revenues		—			1,723.80			1,855.00			(356.6	)		3,222.20
Net investment income		0.4			2,354.50			753.8			29.7			3,138.40
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		6.3			(779.5	)		663.9			0.1			(109.2	)
Total other-than-temporary impairment losses on available-for-sale securities		—			(85.6	)		(5.9	)		—			(91.5	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income		—			(17.0	)		(7.5	)		—			(24.5	)
Net impairment losses on available-for-sale securities		—			(102.6	)		(13.4	)		—			(116.0	)
Net realized capital gains (losses)		6.3			(882.1	)		650.5			0.1			(225.2	)
Total revenues		6.7			5,984.30			3,625.30			(326.8	)		9,289.50
Expenses
Benefits, claims and settlement expenses		—			4,056.60			639.2			(12.2	)		4,683.60
Dividends to policyholders		—			189			—			—			189
Operating expenses		140.5			1,887.70			1,567.50			(302.8	)		3,292.90
Total expenses		140.5			6,133.30			2,206.70			(315.0	)		8,165.50
Income (loss) before income taxes		(133.8	)		(149.0	)		1,418.60			(11.8	)		1,124.00
Income taxes (benefits)		(54.0	)		(167.5	)		412.6			(3.2	)		187.9
Equity in the net income of subsidiaries		992.5			678.1			10.1			(1,680.7	)		—
Net income		912.7			696.6			1,016.10			(1,689.3	)		936.1
Net income attributable to noncontrolling interest		—			—			23.6			(0.2	)		23.4
Net income attributable to PFG		912.7			696.6			992.5			(1,689.1	)		912.7
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	879.7		$	696.6		$	992.5		$	(1,689.1	)	$	879.7
Net income	$	912.7		$	696.6		$	1,016.10		$	(1,689.3	)	$	936.1
Other comprehensive loss		(450.1	)		(146.6	)		(300.1	)		424.9			(471.9	)
Comprehensive income	$	462.6		$	550		$	716		$	(1,264.4	)	$	464.2
Condensed Consolidating Statements of Operations
For the year ended December 31, 2012
	Principal			Principal Life			Principal Financial			Eliminations			Principal
	Financial			Insurance			Services, Inc. and						Financial
	Group, Inc.			Company			Other Subsidiaries						Group, Inc.
	Parent Only			Only			Combined						Consolidated
	(in millions)
Revenues
Premiums and other considerations	$	—		$	2,878.90		$	340.5		$	—		$	3,219.40
Fees and other revenues		0.5			1,529.70			1,404.10			(307.6	)		2,626.70
Net investment income		3			2,484.50			743.1			24.3			3,254.90
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		0.3			(194.8	)		454.8			(27.6	)		232.7
Total other-than-temporary impairment losses on available-for-sale securities		—			(121.1	)		(14.8	)		—			(135.9	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to other comprehensive income		—			13.8			3.5			—			17.3
Net impairment losses on available-for-sale securities		—			(107.3	)		(11.3	)		—			(118.6	)
Net realized capital gains (losses)		0.3			(302.1	)		443.5			(27.6	)		114.1
Total revenues		3.8			6,591.00			2,931.20			(310.9	)		9,215.10
Expenses
Benefits, claims and settlement expenses		—			4,517.80			618.5			(12.4	)		5,123.90
Dividends to policyholders		—			197.7			—			—			197.7
Operating expenses		170.2			1,764.20			1,265.00			(265.9	)		2,933.50
Total expenses		170.2			6,479.70			1,883.50			(278.3	)		8,255.10
Income (loss) before income taxes		(166.4	)		111.3			1,047.70			(32.6	)		960
Income taxes (benefits)		(67.6	)		(83.2	)		287.1			(1.7	)		134.6
Equity in the net income of subsidiaries		905.4			480.4			163.9			(1,549.7	)		—
Net income		806.6			674.9			924.5			(1,580.6	)		825.4
Net income attributable to noncontrolling interest		—			—			19.1			(0.3	)		18.8
Net income attributable to PFG		806.6			674.9			905.4			(1,580.3	)		806.6
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	773.6		$	674.9		$	905.4		$	(1,580.3	)	$	773.6
Net income	$	806.6		$	674.9		$	924.5		$	(1,580.6	)	$	825.4
Other comprehensive income		321.2			315.2			95.1			(361.4	)		370.1
Comprehensive income	$	1,127.80		$	990.1		$	1,019.60		$	(1,942.0	)	$	1,195.50
Condensed Consolidating Statements of Operations
For the year ended December 31, 2011
	Principal			Principal Life			Principal Financial			Eliminations			Principal
	Financial			Insurance			Services, Inc. and						Financial
	Group, Inc.			Company			Other Subsidiaries						Group, Inc.
	Parent Only			Only			Combined						Consolidated
	(in millions)
Revenues
Premiums and other considerations	$	—		$	2,579.60		$	311.4		$	—		$	2,891.00
Fees and other revenues		0.2			1,566.70			1,257.60			(297.8	)		2,526.70
Net investment income (loss)		(12.0	)		2,578.90			763.2			45.2			3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		—			442.8			(388.7	)		20.9			75
Total other-than-temporary impairment losses on available-for-sale securities		—			(130.6	)		(17.0	)		—			(147.6	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income		—			(51.5	)		1.8			—			(49.7	)
Net impairment losses on available-for-sale securities		—			(182.1	)		(15.2	)		—			(197.3	)
Net realized capital gains (losses)		—			260.7			(403.9	)		20.9			(122.3	)
Total revenues		(11.8	)		6,985.90			1,928.30			(231.7	)		8,670.70
Expenses
Benefits, claims and settlement expenses		—			4,013.00			616.9			(13.3	)		4,616.60
Dividends to policyholders		—			210.2			—			—			210.2
Operating expenses		116			1,965.00			1,142.90			(252.8	)		2,971.10
Total expenses		116			6,188.20			1,759.80			(266.1	)		7,797.90
Income (loss) before income taxes		(127.8	)		797.7			168.5			34.4			872.8
Income taxes (benefits)		(50.4	)		267			(18.5	)		0.2			198.3
Equity in the net income of subsidiaries		715.7			7.2			565.1			(1,288.0	)		—
Net income		638.3			537.9			752.1			(1,253.8	)		674.5
Net income attributable to noncontrolling interest		—			—			36.4			(0.2	)		36.2
Net income attributable to PFG		638.3			537.9			715.7			(1,253.6	)		638.3
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	605.3		$	537.9		$	715.7		$	(1,253.6	)	$	605.3
Net income	$	638.3		$	537.9		$	752.1		$	(1,253.8	)	$	674.5
Other comprehensive income (loss)		(34.5	)		100.1			(166.6	)		60.4			(40.6	)
Comprehensive income	$	603.8		$	638		$	585.5		$	(1,193.4	)	$	633.9
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2013
	Principal			Principal Life			Principal			Eliminations			Principal
	Financial			Insurance			Financial						Financial
	Group, Inc.			Company			Services, Inc. and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(42.8	)	$	2,271.70		$	(170.1	)	$	162.4		$	2,221.20
Investing activities
Available-for-sale securities:
Purchases		—			(7,850.8	)		(1,186.1	)		11.7			(9,025.2	)
Sales		—			1,536.00			434			(50.9	)		1,919.10
Maturities		—			6,433.30			925.9			—			7,359.20
Mortgage loans acquired or originated		—			(2,378.4	)		(202.2	)		387.7			(2,192.9	)
Mortgage loans sold or repaid		—			1,918.00			634.3			(457.2	)		2,095.10
Real estate acquired		—			—			(85.6	)		—			(85.6	)
Net purchases of property and equipment		—			(52.4	)		(7.0	)		—			(59.4	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(1,268.3	)		—			(1,268.3	)
Dividends and returns of capital received from unconsolidated entities		319.5			444.2			319.5			(1,083.2	)		—
Net change in other investments		(3.1	)		56.1			(70.2	)		48.9			31.7
Net cash provided by (used in) investing activities		316.4			106			(505.7	)		(1,143.0	)		(1,226.3	)
Financing activities
Issuance of common stock		125.8			—			—			—			125.8
Acquisition of treasury stock		(153.6	)		—			—			—			(153.6	)
Proceeds from financing element derivatives		—			47			—			—			47
Payments for financing element derivatives		—			(48.0	)		—			—			(48.0	)
Excess tax benefits from share-based payment arrangements		—			3.1			7			—			10.1
Purchase of subsidiary shares from noncontrolling interest		—			—			(52.9	)		—			(52.9	)
Sale of subsidiary shares to noncontrolling interest		—			—			31.8			—			31.8
Dividends to common stockholders		(288.4	)		—			—			—			(288.4	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		—			—			38.2			—			38.2
Principal repayments of long-term debt		—			—			(214.4	)		(3.8	)		(218.2	)
Net proceeds from short-term borrowings		—			—			108			—			108
Dividends and capital paid to parent		—			(249.5	)		(763.7	)		1,013.20			—
Investment contract deposits		—			6,355.10			361.2			—			6,716.30
Investment contract withdrawals		—			(8,846.6	)		(6.1	)		—			(8,852.7	)
Net decrease in banking operation deposits		—			—			(225.7	)		—			(225.7	)
Other		—			(5.0	)		—			—			(5.0	)
Net cash used in financing activities		(349.2	)		(2,743.9	)		(716.6	)		1,009.40			(2,800.3	)
Net decrease in cash and cash equivalents		(75.6	)		(366.2	)		(1,392.4	)		28.8			(1,805.4	)
Cash and cash equivalents at beginning of period		207.1			1,698.40			2,286.90			(15.2	)		4,177.20
Cash and cash equivalents at end of period	$	131.5		$	1,332.20		$	894.5		$	13.6		$	2,371.80
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2012
	Principal			Principal Life			Principal			Eliminations			Principal
	Financial			Insurance			Financial						Financial
	Group, Inc.			Company			Services, Inc. and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	204.8		$	3,133.80		$	(382.5	)	$	124.7		$	3,080.80
Investing activities
Available-for-sale securities:
Purchases		—			(7,254.5	)		(1,024.9	)		15.5			(8,263.9	)
Sales		—			1,183.90			134.8			(15.0	)		1,303.70
Maturities		—			5,805.70			841.8			—			6,647.50
Mortgage loans acquired or originated		—			(2,224.8	)		(250.4	)		(63.2	)		(2,538.4	)
Mortgage loans sold or repaid		—			1,422.20			382.3			(136.5	)		1,668.00
Real estate acquired		—			—			(151.8	)		—			(151.8	)
Net purchases of property and equipment		—			(22.2	)		(16.7	)		—			(38.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(80.4	)		—			(80.4	)
Dividends and returns of capital received from (contributions to) unconsolidated entities		(759.2	)		299.2			714.8			(254.8	)		—
Net change in other investments		(0.2	)		(148.4	)		(1.6	)		(6.9	)		(157.1	)
Net cash provided by (used in) investing activities		(759.4	)		(938.9	)		547.9			(460.9	)		(1,611.3	)
Financing activities
Issuance of common stock		28.9			—			—			—			28.9
Acquisition of treasury stock		(272.7	)		—			—			—			(272.7	)
Proceeds from financing element derivatives		—			51.8			—			—			51.8
Payments for financing element derivatives		—			(49.9	)		—			—			(49.9	)
Excess tax benefits from share-based payment arrangements		—			5.1			5.7			—			10.8
Dividends to common stockholders		(231.3	)		—			—			—			(231.3	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		1,483.90			—			9.5			—			1,493.40
Principal repayments of long-term debt		(440.8	)		—			(90.9	)		81.1			(450.6	)
Net repayments of short-term borrowings		—			—			(68.8	)		—			(68.8	)
Capital received from (dividends and capital paid to) parent		—			(714.8	)		460			254.8			—
Investment contract deposits		—			6,401.20			499.2			—			6,900.40
Investment contract withdrawals		—			(7,519.8	)		(2.8	)		—			(7,522.6	)
Net increase in banking operation deposits		—			—			32			—			32
Other		—			(14.6	)		—			—			(14.6	)
Net cash provided by (used in) financing activities		535			(1,841.0	)		843.9			335.9			(126.2	)
Net increase (decrease) in cash and cash equivalents		(19.6	)		353.9			1,009.30			(0.3	)		1,343.30
Cash and cash equivalents at beginning of period		226.7			1,344.50			1,277.60			(14.9	)		2,833.90
Cash and cash equivalents at end of period	$	207.1		$	1,698.40		$	2,286.90		$	(15.2	)	$	4,177.20
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2011
	Principal			Principal Life			Principal			Eliminations			Principal
	Financial			Insurance			Financial						Financial
	Group, Inc.			Company			Services, Inc. and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(73.3	)	$	2,495.50		$	304.7		$	(13.6	)	$	2,713.30
Investing activities
Available-for-sale securities:
Purchases		(4.4	)		(6,047.2	)		(696.8	)		6			(6,742.4	)
Sales		200			689.5			116.2			(25.0	)		980.7
Maturities		4.4			5,037.00			719.4			—			5,760.80
Mortgage loans acquired or originated		—			(1,372.7	)		(169.0	)		56.8			(1,484.9	)
Mortgage loans sold or repaid		—			1,548.60			339.3			(94.8	)		1,793.10
Real estate acquired		—			(0.3	)		(129.6	)		—			(129.9	)
Net purchases of property and equipment		—			(46.7	)		(10.2	)		—			(56.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(270.5	)		—			(270.5	)
Dividends and returns of capital received from unconsolidated entities		506.5			327.9			756.5			(1,590.9	)		—
Net change in other investments		(0.2	)		(48.1	)		84.5			(88.3	)		(52.1	)
Net cash provided by (used in) investing activities		706.3			88			739.8			(1,736.2	)		(202.1	)
Financing activities
Issuance of common stock		25.9			—			—			—			25.9
Acquisition of treasury stock		(556.4	)		—			—			—			(556.4	)
Proceeds from financing element derivatives		—			75.9			—			—			75.9
Payments for financing element derivatives		—			(46.5	)		—			—			(46.5	)
Excess tax benefits from share-based payment arrangements		—			0.8			1.2			—			2
Dividends to common stockholders		(213.7	)		—			—			—			(213.7	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Principal repayments of long-term debt		—			—			(69.4	)		57.2			(12.2	)
Net proceeds from short-term borrowings		—			—			3.2			—			3.2
Dividends and capital paid to parent		—			(756.5	)		(834.4	)		1,590.90			—
Investment contract deposits		—			5,868.70			433.4			—			6,302.10
Investment contract withdrawals		—			(7,076.7	)		(2.3	)		—			(7,079.0	)
Net decrease in banking operation deposits		—			—			(18.5	)		—			(18.5	)
Other		—			(4.5	)		—			—			(4.5	)
Net cash used in financing activities		(777.2	)		(1,938.8	)		(486.8	)		1,648.10			(1,554.7	)
Net increase (decrease) in cash and cash equivalents		(144.2	)		644.7			557.7			(101.7	)		956.5
Cash and cash equivalents at beginning of period		370.9			699.8			719.9			86.8			1,877.40
Cash and cash equivalents at end of period	$	226.7		$	1,344.50		$	1,277.60		$	(14.9	)	$	2,833.90
On May 24, 2011, our shelf registration statement was filed with the SEC and became effective. The shelf registration replaces the shelf registration that had been in effect since June 2008, as it was scheduled to expire in June 2011. Under our current shelf registration, we have the ability to issue unsecured senior debt securities or subordinated debt securities, junior subordinated debt, preferred stock, common stock, warrants, depository shares, stock purchase contracts and stock purchase units of PFG, trust preferred securities of three subsidiary trusts and guarantees by PFG of these trust preferred securities. 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 statement.
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, 2013 and December 31, 2012, and for the years ended December 31, 2013, 2012 and 2011.
In presenting the condensed consolidating financial statements, the equity method of accounting has been applied to (i) PFG's interest in PFS 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.
Condensed Consolidating Statements of Financial Position
December 31, 2013
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance Company						Financial
	Group, Inc.			Services, Inc.			and Other						Group, Inc.
	Parent Only			Only			Subsidiaries						Consolidated
							Combined
	(in millions)
Assets
Fixed maturities, available-for-sale	$	—		$	—		$	48,757.10		$	—		$	48,757.10
Fixed maturities, trading		—			—			563.1			—			563.1
Equity securities, available-for-sale		—			—			110.5			—			110.5
Equity securities, trading		—			—			716.9			—			716.9
Mortgage loans		—			—			11,533.60			—			11,533.60
Real estate		—			—			1,271.60			—			1,271.60
Policy loans		—			—			859.7			—			859.7
Investment in unconsolidated entities		11,956.20			11,647.60			879.8			(23,603.6	)		880
Other investments		9.3			72.7			1,982.50			(0.1	)		2,064.40
Cash and cash equivalents		131.5			688.7			2,384.00			(832.4	)		2,371.80
Accrued investment income		—			—			532.1			—			532.1
Premiums due and other receivables		—			0.1			2,330.40			(1,089.5	)		1,241.00
Deferred acquisition costs		—			—			3,077.00			—			3,077.00
Property and equipment		—			—			500.7			—			500.7
Goodwill		—			—			1,100.30			—			1,100.30
Other intangibles		—			—			1,459.00			—			1,459.00
Separate account assets		—			—			130,018.40			—			130,018.40
Other assets		59.2			94.8			1,181.00			(200.8	)		1,134.20
Total assets	$	12,156.20		$	12,503.90		$	209,257.70		$	(25,726.4	)	$	208,191.40
Liabilities
Contractholder funds	$	—		$	—		$	35,958.30		$	—		$	35,958.30
Future policy benefits and claims		—			—			22,626.20			—			22,626.20
Other policyholder funds		—			—			758.9			—			758.9
Short-term debt		—			—			443			(292.4	)		150.6
Long-term debt		2,448.80			—			1,236.90			(1,084.3	)		2,601.40
Income taxes currently payable		—			2.8			44.7			(42.3	)		5.2
Deferred income taxes		—			—			979.6			(155.6	)		824
Separate account liabilities		—			—			130,018.40			—			130,018.40
Other liabilities		23.2			544.9			5,204.10			(548.0	)		5,224.20
Total liabilities		2,472.00			547.7			197,270.10			(2,122.6	)		198,167.20
Redeemable noncontrolling interest		—			—			247.2			—			247.2
Stockholders' equity
Series A preferred stock		—			—			—			—			—
Series B preferred stock		0.1			—			—			—			0.1
Common stock		4.6			—			17.8			(17.8	)		4.6
Additional paid-in capital		9,798.90			9,163.70			9,057.10			(18,220.8	)		9,798.90
Retained earnings		5,405.40			2,578.20			2,387.20			(4,965.4	)		5,405.40
Accumulated other comprehensive income		183.2			214.3			187.5			(401.8	)		183.2
Treasury stock, at cost		(5,708.0	)		—			(2.0	)		2			(5,708.0	)
Total stockholders' equity attributable to PFG		9,684.20			11,956.20			11,647.60			(23,603.8	)		9,684.20
Noncontrolling interest		—			—			92.8			—			92.8
Total stockholders' equity		9,684.20			11,956.20			11,740.40			(23,603.8	)		9,777.00
Total liabilities and stockholders' equity	$	12,156.20		$	12,503.90		$	209,257.70		$	(25,726.4	)	$	208,191.40
Condensed Consolidating Statements of Financial Position
December 31, 2012
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance Company						Financial
	Group, Inc.			Services, Inc.			and Other						Group, Inc.
	Parent Only			Only			Subsidiaries						Consolidated
							Combined
	(in millions)
Assets
Fixed maturities, available-for-sale	$	—		$	—		$	50,939.30		$	—		$	50,939.30
Fixed maturities, trading		10.5			—			616.2			—			626.7
Equity securities, available-for-sale		—			—			136.5			—			136.5
Equity securities, trading		—			—			252.8			—			252.8
Mortgage loans		—			—			11,519.70			—			11,519.70
Real estate		—			—			1,180.30			—			1,180.30
Policy loans		—			—			864.9			—			864.9
Investment in unconsolidated entities		11,853.30			10,632.10			860.2			(22,476.6	)		869
Other investments		11.1			39.6			2,371.40			—			2,422.10
Cash and cash equivalents		207.1			612.5			4,241.30			(883.7	)		4,177.20
Accrued investment income		—			—			584.4			—			584.4
Premiums due and other receivables		0.1			1,122.10			2,206.70			(2,244.5	)		1,084.40
Deferred acquisition costs		—			—			2,590.00			—			2,590.00
Property and equipment		—			—			464.2			—			464.2
Goodwill		—			—			543.4			—			543.4
Other intangibles		—			—			914.7			—			914.7
Separate account assets		—			—			81,653.80			—			81,653.80
Other assets		78			51			1,003.50			(125.7	)		1,006.80
Total assets	$	12,160.10		$	12,457.30		$	162,943.30		$	(25,730.5	)	$	161,830.20
Liabilities
Contractholder funds	$	—		$	—		$	37,786.50		$	—		$	37,786.50
Future policy benefits and claims		—			—			22,436.20			—			22,436.20
Other policyholder funds		—			—			716.4			—			716.4
Short-term debt		—			—			2,564.10			(2,523.3	)		40.8
Long-term debt		2,448.60			—			222.7			—			2,671.30
Income taxes currently payable		—			0.1			47.2			(32.0	)		15.3
Deferred income taxes		—			—			686.1			(86.1	)		600
Separate account liabilities		—			—			81,653.80			—			81,653.80
Other liabilities		28.1			603.9			6,117.80			(603.7	)		6,146.10
Total liabilities		2,476.70			604			152,230.80			(3,245.1	)		152,066.40
Redeemable noncontrolling interest		—			—			60.4			—			60.4
Stockholders' equity
Series A preferred stock		—			—			—			—			—
Series B preferred stock		0.1			—			—			—			0.1
Common stock		4.5			—			17.8			(17.8	)		4.5
Additional paid-in capital		9,730.90			9,393.80			8,287.70			(17,681.5	)		9,730.90
Retained earnings		4,862.00			1,783.40			1,666.70			(3,450.1	)		4,862.00
Accumulated other comprehensive income		640.3			676.1			661.9			(1,338.0	)		640.3
Treasury stock, at cost		(5,554.4	)		—			(2.0	)		2			(5,554.4	)
Total stockholders' equity attributable to PFG		9,683.40			11,853.30			10,632.10			(22,485.4	)		9,683.40
Noncontrolling interest		—			—			20			—			20
Total stockholders' equity		9,683.40			11,853.30			10,652.10			(22,485.4	)		9,703.40
Total liabilities and stockholders' equity	$	12,160.10		$	12,457.30		$	162,943.30		$	(25,730.5	)	$	161,830.20
Condensed Consolidating Statements of Operations
For the year ended December 31, 2013
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Revenues
Premiums and other considerations	$	—		$	—		$	3,154.10		$	—		$	3,154.10
Fees and other revenues		—			1			3,250.20			(29.0	)		3,222.20
Net investment income		0.4			1.3			3,136.50			0.2			3,138.40
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		6.3			4.6			(120.1	)		—			(109.2	)
Total other-than-temporary impairment losses on available-for-sale securities		—			—			(91.5	)		—			(91.5	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income		—			—			(24.5	)		—			(24.5	)
Net impairment losses on available-for-sale securities		—			—			(116.0	)		—			(116.0	)
Net realized capital gains (losses)		6.3			4.6			(236.1	)		—			(225.2	)
Total revenues		6.7			6.9			9,304.70			(28.8	)		9,289.50
Expenses
Benefits, claims and settlement expenses		—			—			4,683.60			—			4,683.60
Dividends to policyholders		—			—			189			—			189
Operating expenses		140.5			9			3,172.20			(28.8	)		3,292.90
Total expenses		140.5			9			8,044.80			(28.8	)		8,165.50
Income (loss) before income taxes		(133.8	)		(2.1	)		1,259.90			—			1,124.00
Income taxes (benefits)		(54.0	)		(2.9	)		244.8			—			187.9
Equity in the net income of subsidiaries		992.5			991.7			—			(1,984.2	)		—
Net income		912.7			992.5			1,015.10			(1,984.2	)		936.1
Net income attributable to noncontrolling interest		—			—			23.4			—			23.4
Net income attributable to PFG		912.7			992.5			991.7			(1,984.2	)		912.7
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	879.7		$	992.5		$	991.7		$	(1,984.2	)	$	879.7
Net income	$	912.7		$	992.5		$	1,015.10		$	(1,984.2	)	$	936.1
Other comprehensive loss		(450.1	)		(476.4	)		(489.3	)		943.9			(471.9	)
Comprehensive income	$	462.6		$	516.1		$	525.8		$	(1,040.3	)	$	464.2
Condensed Consolidating Statements of Operations
For the year ended December 31, 2012
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Revenues
Premiums and other considerations	$	—		$	—		$	3,219.40		$	—		$	3,219.40
Fees and other revenues		0.5			—			2,627.30			(1.1	)		2,626.70
Net investment income		3			0.4			3,250.80			0.7			3,254.90
Net realized capital gains, excluding impairment losses on available-for-sale securities		0.3			3			229.6			(0.2	)		232.7
Total other-than-temporary impairment losses on available-for-sale securities		—			—			(135.9	)		—			(135.9	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to other comprehensive income		—			—			17.3			—			17.3
Net impairment losses on available-for-sale securities		—			—			(118.6	)		—			(118.6	)
Net realized capital gains		0.3			3			111			(0.2	)		114.1
Total revenues		3.8			3.4			9,208.50			(0.6	)		9,215.10
Expenses
Benefits, claims and settlement expenses		—			—			5,123.90			—			5,123.90
Dividends to policyholders		—			—			197.7			—			197.7
Operating expenses		170.2			9.3			2,754.60			(0.6	)		2,933.50
Total expenses		170.2			9.3			8,076.20			(0.6	)		8,255.10
Income (loss) before income taxes		(166.4	)		(5.9	)		1,132.30			—			960
Income taxes (benefits)		(67.6	)		(6.9	)		209.1			—			134.6
Equity in the net income of subsidiaries		905.4			904.4			—			(1,809.8	)		—
Net income		806.6			905.4			923.2			(1,809.8	)		825.4
Net income attributable to noncontrolling interest		—			—			18.8			—			18.8
Net income attributable to PFG		806.6			905.4			904.4			(1,809.8	)		806.6
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	773.6		$	905.4		$	904.4		$	(1,809.8	)	$	773.6
Net income	$	806.6		$	905.4		$	923.2		$	(1,809.8	)	$	825.4
Other comprehensive income		321.2			366.3			353.7			(671.1	)		370.1
Comprehensive income	$	1,127.80		$	1,271.70		$	1,276.90		$	(2,480.9	)	$	1,195.50
Condensed Consolidating Statements of Operations
For the year ended December 31, 2011
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Revenues
Premiums and other considerations	$	—		$	—		$	2,891.00		$	—		$	2,891.00
Fees and other revenues		0.2			—			2,529.50			(3.0	)		2,526.70
Net investment income (loss)		(12.0	)		(3.2	)		3,387.50			3			3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		—			(0.1	)		75.1			—			75
Total other-than-temporary impairment losses on available-for-sale securities		—			—			(147.6	)		—			(147.6	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income		—			—			(49.7	)		—			(49.7	)
Net impairment losses on available-for-sale securities		—			—			(197.3	)		—			(197.3	)
Net realized capital losses		—			(0.1	)		(122.2	)		—			(122.3	)
Total revenues		(11.8	)		(3.3	)		8,685.80			—			8,670.70
Expenses
Benefits, claims and settlement expenses		—			—			4,616.60			—			4,616.60
Dividends to policyholders		—			—			210.2			—			210.2
Operating expenses		116			1.7			2,853.40			—			2,971.10
Total expenses		116			1.7			7,680.20			—			7,797.90
Income (loss) before income taxes		(127.8	)		(5.0	)		1,005.60			—			872.8
Income taxes (benefits)		(50.4	)		(9.9	)		258.6			—			198.3
Equity in the net income of subsidiaries		715.7			710.8			—			(1,426.5	)		—
Net income		638.3			715.7			747			(1,426.5	)		674.5
Net income attributable to noncontrolling interest		—			—			36.2			—			36.2
Net income attributable to PFG		638.3			715.7			710.8			(1,426.5	)		638.3
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	605.3		$	715.7		$	710.8		$	(1,426.5	)	$	605.3
Net income	$	638.3		$	715.7		$	747		$	(1,426.5	)	$	674.5
Other comprehensive loss		(34.5	)		(44.0	)		(51.1	)		89			(40.6	)
Comprehensive income	$	603.8		$	671.7		$	695.9		$	(1,337.5	)	$	633.9
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2013
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(42.8	)	$	1,019.00		$	2,340.20		$	(1,095.2	)	$	2,221.20
Investing activities
Available-for-sale securities:
Purchases		—			—			(9,025.2	)		—			(9,025.2	)
Sales		—			—			1,919.10			—			1,919.10
Maturities		—			—			7,359.20			—			7,359.20
Mortgage loans acquired or originated		—			—			(2,192.9	)		—			(2,192.9	)
Mortgage loans sold or repaid		—			—			2,095.10			—			2,095.10
Real estate acquired		—			—			(85.6	)		—			(85.6	)
Net purchases of property and equipment		—			—			(59.4	)		—			(59.4	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(1,268.3	)		—			(1,268.3	)
Dividends and returns of capital received from (contributions to) unconsolidated entities		319.5			(594.6	)		—			275.1			—
Net change in other investments		(3.1	)		(28.7	)		63.5			—			31.7
Net cash provided by (used in) investing activities		316.4			(623.3	)		(1,194.5	)		275.1			(1,226.3	)
Financing activities
Issuance of common stock		125.8			—			—			—			125.8
Acquisition of treasury stock		(153.6	)		—			—			—			(153.6	)
Proceeds from financing element derivatives		—			—			47			—			47
Payments for financing element derivatives		—			—			(48.0	)		—			(48.0	)
Excess tax benefits from share-based payment arrangements		—			—			10.1			—			10.1
Purchase of subsidiary shares from noncontrolling interest		—			—			(52.9	)		—			(52.9	)
Sale of subsidiary shares to noncontrolling interest		—			—			31.8			—			31.8
Dividends to common stockholders		(288.4	)		—			—			—			(288.4	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		—			—			1,122.50			(1,084.3	)		38.2
Principal repayments of long-term debt		—			—			(218.2	)		—			(218.2	)
Net proceeds from (repayments of) short-term borrowings		—			—			(2,122.8	)		2,230.80			108
Capital received from (dividends and capital paid to) parent		—			(319.5	)		594.6			(275.1	)		—
Investment contract deposits		—			—			6,716.30			—			6,716.30
Investment contract withdrawals		—			—			(8,852.7	)		—			(8,852.7	)
Net decrease in banking operation deposits		—			—			(225.7	)		—			(225.7	)
Other		—			—			(5.0	)		—			(5.0	)
Net cash used in financing activities		(349.2	)		(319.5	)		(3,003.0	)		871.4			(2,800.3	)
Net increase (decrease) in cash and cash equivalents		(75.6	)		76.2			(1,857.3	)		51.3			(1,805.4	)
Cash and cash equivalents at beginning of period		207.1			612.5			4,241.30			(883.7	)		4,177.20
Cash and cash equivalents at end of period	$	131.5		$	688.7		$	2,384.00		$	(832.4	)	$	2,371.80
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2012
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	204.8		$	(1,145.0	)	$	1,762.00		$	2,259.00		$	3,080.80
Investing activities
Available-for-sale securities:
Purchases		—			—			(8,263.9	)		—			(8,263.9	)
Sales		—			—			1,303.70			—			1,303.70
Maturities		—			—			6,647.50			—			6,647.50
Mortgage loans acquired or originated		—			—			(2,538.4	)		—			(2,538.4	)
Mortgage loans sold or repaid		—			—			1,668.00			—			1,668.00
Real estate acquired		—			—			(151.8	)		—			(151.8	)
Net purchases of property and equipment		—			—			(38.9	)		—			(38.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(80.4	)		—			(80.4	)
Dividends and returns of capital received from (contributions to) unconsolidated entities		(759.2	)		381			—			378.2			—
Net change in other investments		(0.2	)		(35.1	)		(121.8	)		—			(157.1	)
Net cash provided by (used in) investing activities		(759.4	)		345.9			(1,576.0	)		378.2			(1,611.3	)
Financing activities
Issuance of common stock		28.9			—			—			—			28.9
Acquisition of treasury stock		(272.7	)		—			—			—			(272.7	)
Proceeds from financing element derivatives		—			—			51.8			—			51.8
Payments for financing element derivatives		—			—			(49.9	)		—			(49.9	)
Excess tax benefits from share-based payment arrangements		—			—			10.8			—			10.8
Dividends to common stockholders		(231.3	)		—			—			—			(231.3	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		1,483.90			—			9.5			—			1,493.40
Principal repayments of long-term debt		(440.8	)		—			(9.8	)		—			(450.6	)
Net proceeds from (repayments of) short-term borrowings		—			(50.0	)		2,240.80			(2,259.6	)		(68.8	)
Capital received from (dividends and capital paid to) parent		—			759.2			(381.0	)		(378.2	)		—
Investment contract deposits		—			—			6,900.40			—			6,900.40
Investment contract withdrawals		—			—			(7,522.6	)		—			(7,522.6	)
Net increase in banking operation deposits		—			—			32			—			32
Other		—			—			(14.6	)		—			(14.6	)
Net cash provided by (used in) financing activities		535			709.2			1,267.40			(2,637.8	)		(126.2	)
Net increase (decrease) in cash and cash equivalents		(19.6	)		(89.9	)		1,453.40			(0.6	)		1,343.30
Cash and cash equivalents at beginning of period		226.7			702.4			2,787.90			(883.1	)		2,833.90
Cash and cash equivalents at end of period	$	207.1		$	612.5		$	4,241.30		$	(883.7	)	$	4,177.20
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2011
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(73.3	)	$	70.5		$	2,795.00		$	(78.9	)	$	2,713.30
Investing activities
Available-for-sale securities:
Purchases		(4.4	)		—			(6,738.0	)		—			(6,742.4	)
Sales		200			—			780.7			—			980.7
Maturities		4.4			—			5,756.40			—			5,760.80
Mortgage loans acquired or originated		—			—			(1,484.9	)		—			(1,484.9	)
Mortgage loans sold or repaid		—			—			1,793.10			—			1,793.10
Real estate acquired		—			—			(129.9	)		—			(129.9	)
Net purchases of property and equipment		—			—			(56.9	)		—			(56.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(270.5	)		—			(270.5	)
Dividends and returns of capital received from unconsolidated entities		506.5			624.1			—			(1,130.6	)		—
Net change in other investments		(0.2	)		(5.4	)		(46.5	)		—			(52.1	)
Net cash provided by (used in) investing activities		706.3			618.7			(396.5	)		(1,130.6	)		(202.1	)
Financing activities
Issuance of common stock		25.9			—			—			—			25.9
Acquisition of treasury stock		(556.4	)		—			—			—			(556.4	)
Proceeds from financing element derivatives		—			—			75.9			—			75.9
Payments for financing element derivatives		—			—			(46.5	)		—			(46.5	)
Excess tax benefits from share-based payment arrangements		—			—			2			—			2
Dividends to common stockholders		(213.7	)		—			—			—			(213.7	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Principal repayments of long-term debt		—			—			(12.2	)		—			(12.2	)
Net proceeds from (repayments of) short-term borrowings		—			—			(27.5	)		30.7			3.2
Dividends and capital paid to parent		—			(506.5	)		(624.1	)		1,130.60			—
Investment contract deposits		—			—			6,302.10			—			6,302.10
Investment contract withdrawals		—			—			(7,079.0	)		—			(7,079.0	)
Net decrease in banking operation deposits		—			—			(18.5	)		—			(18.5	)
Other		—			—			(4.5	)		—			(4.5	)
Net cash used in financing activities		(777.2	)		(506.5	)		(1,432.3	)		1,161.30			(1,554.7	)
Net increase (decrease) in cash and cash equivalents		(144.2	)		182.7			966.2			(48.2	)		956.5
Cash and cash equivalents at beginning of period		370.9			519.7			1,821.70			(834.9	)		1,877.40
Cash and cash equivalents at end of period	$	226.7		$	702.4		$	2,787.90		$	(883.1	)	$	2,833.90

Schedule_I_Summary_of_Investme

Schedule I - Summary of Investments - Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2013
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
	As of December 31, 2013
	Type of Investment	Cost		Value		Amount as
						shown in the
						Consolidated
						Statement of
						Financial
						Position
		(in millions)
	Fixed maturities, available-for-sale:
	U.S Treasury securities and obligations of U.S government corporations and agencies	$	818.2	$	780.5	$	780.5
	States, municipalities and political subdivisions		3,622.80		3,658.00		3,658.00
	Foreign governments		853.2		996.8		996.8
	Public utilities		4,846.60		4,424.00		4,424.00
	Redeemable preferred stock		37.8		41.2		41.2
	All other corporate bonds		25,396.20		27,453.80		27,453.80
	Residential mortgage-backed securities		2,799.10		2,845.20		2,845.20
	Commercial mortgage-backed securities		4,078.00		4,026.40		4,026.40
	Collateralized debt obligations		391.9		363.4		363.4
	Other debt obligations		4,157.50		4,167.80		4,167.80
	Total fixed maturities, available-for-sale		47,001.30		48,757.10		48,757.10
	Fixed maturities, trading		563.1		563.1		563.1
	Equity securities, available-for-sale:
	Banks, trust and insurance companies		60.8		51.1		51.1
	Industrial, miscellaneous and all other		7.7		10.2		10.2
	Non-redeemable preferred stock		45.3		49.2		49.2
	Total equity securities, available-for-sale		113.8		110.5		110.5
	Equity securities, trading		716.9		716.9		716.9
	Mortgage loans (1)		11,603.30		XXXX		11,533.60
	Real estate, net:
	Real estate acquired in satisfaction of debt		213.6		XXXX		213.8
	Other real estate		1,058.00		XXXX		1,057.80
	Policy loans		859.7		XXXX		859.7
	Other investments (2)		1,542.00		XXXX		2,944.40
	Total investments	$	63,671.70		XXXX	$	66,756.90
	-1
	The amount shown in the Consolidated Statement of Financial Position for mortgage loans differs from cost as 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.
	-2
	The amount shown in the Consolidated Statement of Financial Position for other investments differs from cost due to accumulated earnings from minority interests in unconsolidated entities and properties owned jointly with venture partners and operated by the partners. Other investments also includes derivative assets and certain seed money investments, which are reported at fair value, and commercial mortgage loans of consolidated VIEs for which the fair value option was elected.

Schedule_II_Condensed_Financia

Schedule II - Condensed Financial Information of Registrant (Parent Only)	12 Months Ended
	Dec. 31, 2013
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,
		2013			2012
		(in millions)
	Assets
	Fixed maturities, trading	$	—		$	10.5
	Cash and cash equivalents		131.5			207.1
	Other investments		9.3			11.1
	Income taxes receivable		22.2			35.8
	Deferred income taxes		17.2			20.6
	Amounts receivable from subsidiary		0.8			0.9
	Other assets		19			20.8
	Investment in subsidiary		11,956.20			11,853.30
	Total assets	$	12,156.20		$	12,160.10
	Liabilities
	Amounts payable to subsidiary	$	1.4		$	2.1
	Long-term debt		2,448.80			2,448.60
	Accrued investment payable		21.8			22.3
	Other liabilities		—			3.7
	Total liabilities		2,472.00			2,476.70
	Stockholders' equity
	Series A preferred stock, par value $0.01 per share with liquidation preference of $100 per share — 3.0 million shares authorized, issued and outstanding in 2013 and 2012		—			—
	Series B preferred stock, par value $0.01 per share with liquidation preference of $25 per share — 10.0 million shares authorized, issued and outstanding in 2013 and 2012		0.1			0.1
	Common stock, par value $.01 per share — 2,500 million shares authorized, 459.3 million and 453.5 million shares issued, and 295.2 million and 293.8 million shares outstanding in 2013 and 2012		4.6			4.5
	Additional paid-in capital		9,798.90			9,730.90
	Retained earnings		5,405.40			4,862.00
	Accumulated other comprehensive income		183.2			640.3
	Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)		(5,708.0	)		(5,554.4	)
	Total stockholders' equity attributable to Principal Financial Group, Inc.		9,684.20			9,683.40
	Total liabilities and stockholders' equity	$	12,156.20		$	12,160.10
	See accompanying notes.
	Statements of Operations
		For the year ended December 31,
		2013			2012			2011
		(in millions)
	Revenues
	Fees and other revenues	$	—		$	0.5		$	0.2
	Net investment income (loss)		0.4			3			(12.0	)
	Net realized capital gains		6.3			0.3			—
	Total revenues		6.7			3.8			(11.8	)
	Expenses
	Other operating costs and expenses		140.5			170.2			116
	Total expenses		140.5			170.2			116
	Losses before income taxes		(133.8	)		(166.4	)		(127.8	)
	Income tax benefits		(54.0	)		(67.6	)		(50.4	)
	Equity in the net income of subsidiaries		992.5			905.4			715.7
	Net income attributable to Principal Financial Group, Inc.		912.7			806.6			638.3
	Preferred stock dividends		33			33			33
	Net income available to common stockholders	$	879.7		$	773.6		$	605.3
	See accompanying notes.
	Statements of Cash Flows
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Operating activities
	Net income	$	912.7		$	806.6		$	638.3
	Adjustments to reconcile net income to net cash provided by (used in) operating activities:
	Equity in the net income of subsidiaries		(992.5	)		(905.4	)		(715.7	)
	Net realized capital gains		(6.3	)		(0.3	)		—
	Net cash flows for trading securities		10.4			258.2			21.7
	Current and deferred income tax benefits		12.6			(2.3	)		(3.7	)
Stock-based compensation		2.2			2.2			1.6
Other		18.1			45.8			(15.5	)
Net cash provided by (used in) operating activities		(42.8	)		204.8			(73.3	)
Investing activities
Available-for-sale securities:
Purchases		—			—			(4.4	)
Sales		—			—			200
Maturities		—			—			4.4
Net change in other investments		(3.1	)		(0.2	)		(0.2	)
Dividends and returns of capital received from (contributions to) unconsolidated entity		319.5			(759.2	)		506.5
Net cash provided by (used in) investing activities		316.4			(759.4	)		706.3
Financing activities
Issuance of common stock		125.8			28.9			25.9
Acquisition of treasury stock		(153.6	)		(272.7	)		(556.4	)
Dividends to common stockholders		(288.4	)		(231.3	)		(213.7	)
Dividends to preferred stockholders		(33.0	)		(33.0	)		(33.0	)
Principal repayments of long term debt		—			(440.8	)		—
Issuance of long-term debt		—			1,483.90			—
Net cash provided by (used in) financing activities		(349.2	)		535			(777.2	)
Net decrease in cash and cash equivalents		(75.6	)		(19.6	)		(144.2	)
Cash and cash equivalents at beginning of year		207.1			226.7			370.9
Cash and cash equivalents at end of year	$	131.5		$	207.1		$	226.7
See accompanying notes
(1)   Basis of Presentation
The accompanying condensed financial statement 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 investments in subsidiaries are stated as cost plus equity in undistributed earnings of subsidiaries.
(2)   Cash Dividends and Returns of Capital Received from (Capital Contributed to) Unconsolidated Entity
The parent company received cash dividends and returns of capital totaling $319.5 million in 2013 from its unconsolidated entity. The parent company contributed capital of $759.2 million to its unconsolidated entity in 2012. In 2011, the parent company received cash dividends and returns of capital totaling $506.5 million.

Schedule_III_Supplementary_Ins

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2013
Schedule III - Supplementary Insurance Information	'
Schedule III - Supplementary Insurance Information	'
	Schedule III — Supplementary Insurance Information
	As of December 31, 2013 and 2012 and for each of the years ended December 31, 2013, 2012 and 2011
	Segment	Deferred		Future policy		Contractholder
		acquisition		benefits and		and other
		costs		claims		policyholder
						funds
		(in millions)
	2013:00:00
	Retirement and Investor Services	$	848.9	$	9,975.60	$	30,537.50
	Principal Global Investors		—		—		—
	Principal International		228.2		4,220.20		172.2
	U.S. Insurance Solutions		1,999.90		8,389.00		6,293.90
	Corporate		—		41.4		(286.4	)
	Total	$	3,077.00	$	22,626.20	$	36,717.20
	2012:00:00
	Retirement and Investor Services	$	699.4	$	9,702.70	$	32,801.40
	Principal Global Investors		—		—		—
	Principal International		195.3		4,435.50		108.5
	U.S. Insurance Solutions		1,695.30		8,247.60		5,867.40
	Corporate		—		50.4		(274.4	)
	Total	$	2,590.00	$	22,436.20	$	38,502.90
	Segment	Premiums and		Net		Benefits, claims			Amortization of			Other
		other		investment		and settlement			deferred			operating
		considerations		income (1)		expenses			acquisition			expenses (1)
									costs
		(in millions)
	2013:00:00
	Retirement and Investor Services	$	1,045.50	$	1,933.30	$	2,303.40		$	75		$	1,529.90
	Principal Global Investors		—		17		—			—			545.7
	Principal International		291.6		447.1		569			16.5			318
	U.S. Insurance Solutions		1,816.50		686.3		1,826.00			95.6			689
	Corporate		0.5		54.7		(14.8	)		—			23.2
	Total	$	3,154.10	$	3,138.40	$	4,683.60		$	187.1		$	3,105.80
	2012:00:00
	Retirement and Investor Services	$	1,162.60	$	2,075.40	$	2,629.10		$	84.8		$	1,362.50
	Principal Global Investors		—		15.4		—			—			456.9
	Principal International		284.6		435.2		567.2			12.6			208.5
	U.S. Insurance Solutions		1,769.30		675.2		1,935.50			(2.5	)		662
	Corporate		2.9		53.7		(7.9	)		—			148.7
	Total	$	3,219.40	$	3,254.90	$	5,123.90		$	94.9		$	2,838.60
	2011:00:00
	Retirement and Investor Services	$	390.4	$	2,182.80	$	1,933.30		$	119.4		$	1,258.50
	Principal Global Investors		—		15.1		—			—			429.3
	Principal International		264.5		469.9		581.7			8.4			184.8
	U.S. Insurance Solutions		1,724.00		669.9		1,725.10			143.6			630.2
	Corporate		512.1		37.6		376.5			—			196.9
	Total	$	2,891.00	$	3,375.30	$	4,616.60		$	271.4		$	2,699.70
	-1
	Allocations of net investment income and certain operating expenses are based on a number of assumptions and estimates, and reported operating results would change by segment if different methods were applied.

Schedule_IV_Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2013
Schedule IV - Reinsurance	'
Schedule IV - Reinsurance	'
	Schedule IV — Reinsurance
	As of December 31, 2013, 2012 and 2011 and for each of the years then ended
		Gross		Ceded to		Assumed		Net amount		Percentage
		amount		other		from other				of amount
				companies		companies				assumed
										to net
		($ in millions)
	2013:00:00
	Life insurance in force	$	317,154.50	$	144,024.90	$	1,455.40	$	174,585.00		0.8	%
	Premiums:
	Life insurance	$	2,216.90	$	205.2	$	2.5	$	2,014.20		0.1	%
	Accident and health insurance		1,307.90		168		—		1,139.90		—	%
	Total	$	3,524.80	$	373.2	$	2.5	$	3,154.10		0.1	%
	2012:00:00
	Life insurance in force	$	286,435.30	$	115,315.70	$	1,606.20	$	172,725.80		0.9	%
	Premiums:
	Life insurance	$	2,289.40	$	174.4	$	2.6	$	2,117.60		0.1	%
	Accident and health insurance		1,264.70		162.9		—		1,101.80		—	%
	Total	$	3,554.10	$	337.3	$	2.6	$	3,219.40		0.1	%
	2011:00:00
	Life insurance in force	$	256,880.30	$	94,839.70	$	1,814.90	$	163,855.50		1.1	%
	Premiums:
	Life insurance	$	1,490.80	$	158.5	$	3	$	1,335.30		0.2	%
	Accident and health insurance		1,714.80		159.1		—		1,555.70		—	%
	Total	$	3,205.60	$	317.6	$	3	$	2,891.00		0.1	%

Nature_of_Operations_and_Signi1

Nature of Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Nature of Operations and Significant Accounting Policies	'
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, redeemable preferred stock and certain nonredeemable preferred securities. Equity securities include mutual funds, common stock and nonredeemable preferred stock. We classify fixed maturities and equity securities as either available-for-sale or trading at the time of the purchase and, accordingly, carry them at fair value. See Note 15, Fair Value Measurements, for methodologies related to the determination of fair value. Unrealized gains and losses related to available-for-sale securities, excluding those in fair value hedging relationships, are reflected in stockholders' equity, net of adjustments related to DAC, reinsurance assets or liabilities, sales inducements, unearned revenue reserves, policyholder liabilities, derivatives in cash flow hedge relationships and applicable income taxes. Unrealized gains and losses related to hedged portions of available-for-sale securities in fair value hedging relationships and mark-to-market adjustments on certain trading securities are reflected in net realized capital gains (losses). We also have certain equity securities, trading that represent mandatory required investments and a minimal amount of assets within trading securities portfolios that support investment strategies that involve the active and frequent purchase and sale of fixed maturities. Mark-to-market adjustments related to these trading securities are reflected in net investment income.
	The cost of fixed maturities is adjusted for amortization of premiums and accrual of discounts, both computed using the interest method. The cost of fixed maturities and equity securities classified as available-for-sale is adjusted for declines in value that are other than temporary. Impairments in value deemed to be other than temporary are 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.
	Real estate investments are reported at cost less accumulated depreciation. The initial cost basis 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 properties are 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 $182.3 million and $87.0 million as of December 31, 2013 and 2012, respectively. Any impairment losses and any changes in valuation allowances are reported in net income.
	Commercial and residential mortgage loans are generally reported at cost adjusted for amortization of premiums and accrual of discounts, computed using the interest method, net of valuation allowances. 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. Any changes in the valuation allowances are reported in net income as net realized capital gains (losses). We measure impairment based upon the difference between carrying value and estimated value less cost to sell. Estimated value is based on either the present value of expected cash flows discounted at the loan's effective interest rate, the loan's observable market price or the fair value of the collateral. If foreclosure is probable, the measurement of any valuation allowance is based upon the fair value of the collateral.
	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): other-than-temporary impairments of securities and subsequent realized recoveries, mark-to-market adjustments on certain trading securities, mark-to-market adjustments on certain seed money investments, fair value hedge and cash flow hedge ineffectiveness, mark-to-market adjustments on derivatives not designated as hedges, changes in the mortgage loan valuation allowance provision and impairments of real estate held for investment. Investment gains and losses on sales of certain real estate held for sale that do not meet the criteria for classification as a discontinued operation, mark-to-market adjustments on certain equity securities, trading that represent mandatory required investments and mark-to-market adjustments on trading securities that support investment strategies that involve the active and frequent purchase and sale of fixed maturities are reported as net investment income and are excluded from net realized capital gains (losses).
	Policy loans and other investments, excluding investments in unconsolidated entities and commercial mortgage loans of consolidated VIEs for which the fair value option was elected, are primarily reported at cost.
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 interest rate swaps, interest rate options, swaptions, currency swaps, currency forwards, currency options, equity options, futures, credit default swaps and total return swaps. Derivatives may be exchange traded, cleared through centralized clearinghouses, or contracted in the over-the-counter market without being cleared. 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 15, 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.
	Fair Value Hedges.    When a derivative is designated as a fair value hedge and is determined to be highly effective, changes in its fair value, along with changes in the fair value of the hedged asset, liability or firm commitment attributable to the hedged risk, are reported in net realized capital gains (losses). Any difference between the net change in fair value of the derivative and the hedged item represents hedge ineffectiveness.
	Cash Flow Hedges.    When a derivative is designated as a cash flow hedge and is determined to be highly effective, changes in its fair value are recorded as a component of OCI. Any hedge ineffectiveness is recorded immediately in net income. At the time the variability of cash flows being hedged impacts net income, the related portion of deferred gains or losses on the derivative instrument is reclassified and reported in net income.
	Net Investment in a Foreign Operation Hedge.    When a derivative is used as a hedge of a net investment in a foreign operation, its change in fair value, to the extent effective as a hedge, is recorded as a component of OCI. Any hedge ineffectiveness is recorded immediately in net income. If the foreign operation is sold or upon complete or substantially complete liquidation, the deferred gains or losses on the derivative instrument are reclassified into net income.
	Non-Hedge Derivatives.    If a derivative does not qualify or is not designated for hedge accounting, all changes in fair value are reported in net income without considering the changes in the fair value of the economically associated assets or liabilities.
	Hedge Documentation and Effectiveness Testing.    At inception, we formally document all relationships between hedging instruments and hedged items, as well as our risk management objective and strategy for undertaking various hedge transactions. This process includes associating all derivatives designated as fair value or cash flow hedges with specific assets or liabilities on the statement of financial position or with specific firm commitments or forecasted transactions. Effectiveness of the hedge is formally assessed at inception and throughout the life of the hedging relationship. Even if a derivative is highly effective and qualifies for hedge accounting treatment, the hedge might have some ineffectiveness.
	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.    We prospectively discontinue hedge accounting when (1) the criteria to qualify for hedge accounting is no longer met, e.g., a derivative is determined to no longer be highly effective in offsetting the change in fair value or cash flows of a hedged item; (2) the derivative expires, is sold, terminated or exercised or (3) we remove the designation of the derivative being the hedging instrument for a fair value or cash flow hedge.
	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 OCI 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 OCI into net income.
	Embedded Derivatives.    We purchase and issue certain financial instruments and products that contain a derivative that is embedded in the financial instrument or product. We assess whether this embedded derivative is clearly and closely related to the asset or liability that serves as its host contract. If we deem that the embedded derivative's terms are not clearly and closely related to the host contract, and a separate instrument with the same terms would qualify as a derivative instrument, the derivative is bifurcated from that contract and held at fair value on the consolidated statements of financial position, with changes in fair value reported in net income.
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 and reserves for universal life, term life insurance, participating traditional individual life insurance, group life insurance, health insurance and disability income policies, as well as 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 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 contracts that contain no lapse guarantee features, or annuities with guaranteed minimum death benefits.
	Reserves for 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.
	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 12%, 13% and 15% of our life insurance in force and 43%, 47% and 50% of the number of life insurance policies in force at December 31, 2013, 2012 and 2011, respectively. Participating business represented approximately 40%, 43% and 47% of life insurance premiums for the years ended December 31, 2013, 2012 and 2011, 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 operations over the estimated lives of these policies and contracts in relation to the emergence of estimated gross profit margins.
	The liability for unpaid disability and health claims 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 that 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.
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
	Traditional individual life insurance products include those products with fixed and guaranteed premiums and benefits and consist principally of whole life and term life insurance policies. 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 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 and health insurance 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 for group life and health insurance products 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 services provided to retail and institutional clients based largely upon contractual rates applied to the market value of the client's portfolio. Additionally, fees and other revenues are earned for administrative services performed including recordkeeping and reporting services for retirement savings plans. 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 of contract acquisition 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 operations as incurred.
	DAC for universal life-type insurance contracts, participating life insurance policies and certain investment contracts are being amortized over the lives of the policies and contracts in relation to the emergence of estimated gross profits ("EGPs") or, in certain circumstances, estimated gross revenues. This amortization is adjusted in the current period when EGPs or estimated gross revenues are revised. For individual variable life insurance, individual variable annuities and group annuities that have separate account U.S. equity investment options, we utilize a mean reversion method (reversion to the mean assumption), a common industry practice, to determine the future domestic equity market growth assumption used for the amortization of DAC. The DAC of nonparticipating term life insurance and individual disability policies are being amortized over the premium-paying period of the related policies using assumptions consistent with those used in computing policyholder liabilities.
	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 is necessary, DAC would be written off to the extent that it is determined that future policy premiums and investment income or gross profits are not adequate to cover related losses and expenses.
	DAC on long-term service contracts are amortized in proportion to the revenue recognized or straight-line if no pattern of revenue recognition can be reasonably predicted. We amortize capitalized costs of long-term service contracts on a straight-line basis over the expected contract life.
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 statement of financial position.
Reinsurance - Policy	'
	Reinsurance
	We enter into reinsurance agreements with other companies in the normal course of business. 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. At December 31, 2013 and 2012, our largest exposures to a single third-party reinsurer was in our life insurance business, which totaled $35.9 billion and $29.7 billion of life insurance in force, representing 17% and 18% of total net life insurance in force, respectively. The reinsurance recoverable relating to paid and unpaid claims associated to this single third party reinsurer recorded in our consolidated statements of financial position was $31.3 million and $26.1 million at December 31, 2013 and 2012, respectively.
	The effects of reinsurance on premiums and other considerations and policy and contract benefits were as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Premiums and other considerations:
	Direct	$	3,524.80		$	3,554.10		$	3,205.60
	Assumed		2.5			2.6			3
	Ceded		(373.2	)		(337.3	)		(317.6	)
	Net premiums and other considerations	$	3,154.10		$	3,219.40		$	2,891.00
	Benefits, claims and settlement expenses:
	Direct	$	4,933.30		$	5,268.60		$	4,926.50
	Assumed		32.2			33.9			34
	Ceded		(281.9	)		(178.6	)		(343.9	)
	Net benefits, claims and settlement expenses	$	4,683.60		$	5,123.90		$	4,616.60
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 statement 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 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.
	At December 31, 2013 and December 31, 2012, the separate accounts include a separate account valued at $223.1 million and $148.3 million, respectively, which primarily includes 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 to eligible participants of the qualified plan. 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 and net operating losses 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 operations in the period in which the change is enacted.
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 to which it was assigned. A reporting unit is an operating segment or a business one level below that 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 consists of 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 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_Signi2

Nature of Operations and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Nature of Operations and Significant Accounting Policies	'
Effects of Deferred Acquisition Cost Accounting Change on Prior Period Consolidated Statements of Financial Position (Table)	'
		December 31, 2012
		As originally			As adjusted
		reported
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	50,939.30		$	50,939.30
	Fixed maturities, trading		626.7			626.7
	Equity securities, available-for-sale		136.5			136.5
	Equity securities, trading		252.8			252.8
	Mortgage loans		11,519.70			11,519.70
	Real estate		1,180.30			1,180.30
	Policy loans		864.9			864.9
	Other investments		3,291.10			3,291.10
	Total investments		68,811.30			68,811.30
	Cash and cash equivalents		4,177.20			4,177.20
	Accrued investment income		584.4			584.4
	Premiums due and other receivables		1,084.40			1,084.40
	Deferred acquisition costs		2,673.80			2,590.00
	Property and equipment		464.2			464.2
	Goodwill		543.4			543.4
	Other intangibles		927.2			914.7
	Separate account assets		81,653.80			81,653.80
	Other assets		1,006.80			1,006.80
	Total assets	$	161,926.50		$	161,830.20
	Liabilities
	Contractholder funds	$	37,786.50		$	37,786.50
	Future policy benefits and claims		22,436.20			22,436.20
	Other policyholder funds		716.4			716.4
	Short-term debt		40.8			40.8
	Long-term debt		2,671.30			2,671.30
	Income taxes currently payable		15.3			15.3
	Deferred income taxes		626.5			600
	Separate account liabilities		81,653.80			81,653.80
	Other liabilities		6,146.10			6,146.10
	Total liabilities		152,092.90			152,066.40
	Redeemable noncontrolling interest		60.4			60.4
	Stockholders' equity
	Series A preferred stock, par value		—			—
	Series B preferred stock, par value		0.1			0.1
	Common stock, par value		4.5			4.5
	Additional paid-in capital		9,730.90			9,730.90
	Retained earnings		4,940.20			4,862.00
	Accumulated other comprehensive income		631.9			640.3
	Treasury stock, at cost		(5,554.4	)		(5,554.4	)
	Total stockholders' equity attributable to Principal Financial Group, Inc.		9,753.20			9,683.40
	Noncontrolling interest		20			20
	Total stockholders' equity		9,773.20			9,703.40
	Total liabilities and stockholders' equity	$	161,926.50		$	161,830.20
Effects of Deferred Acquisition Cost Accounting Change on Prior Period Consolidated Statements of Operations (Table)	'
		For the year ended						For the year ended
		December 31, 2012						December 31, 2011
		As originally			As adjusted			As originally			As adjusted
		reported						reported
		(in millions, except per share data)
	Revenues
	Premiums and other considerations	$	3,219.40		$	3,219.40		$	2,891.00		$	2,891.00
	Fees and other revenues		2,626.70			2,626.70			2,526.70			2,526.70
	Net investment income		3,254.90			3,254.90			3,375.30			3,375.30
	Net realized capital gains, excluding impairment losses on available-for-sale securities		232.7			232.7			75			75
	Total other-than-temporary impairment losses on available-for- sale securities		(135.9	)		(135.9	)		(147.6	)		(147.6	)
	Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income		17.3			17.3			(49.7	)		(49.7	)
	Net impairment losses on available-for-sale securities		(118.6	)		(118.6	)		(197.3	)		(197.3	)
	Net realized capital gains (losses)		114.1			114.1			(122.3	)		(122.3	)
	Total revenues		9,215.10			9,215.10			8,670.70			8,670.70
	Expenses
	Benefits, claims and settlement expenses		5,123.90			5,123.90			4,616.60			4,616.60
	Dividends to policyholders		197.7			197.7			210.2			210.2
	Operating expenses		2,934.10			2,933.50			2,950.80			2,971.10
	Total expenses		8,255.70			8,255.10			7,777.60			7,797.90
	Income before income taxes		959.4			960			893.1			872.8
	Income taxes		134.7			134.6			204.2			198.3
	Net income		824.7			825.4			688.9			674.5
	Net income attributable to noncontrolling interest		18.8			18.8			36.2			36.2
	Net income attributable to Principal Financial Group, Inc.		805.9			806.6			652.7			638.3
	Preferred stock dividends		33			33			33			33
	Net income available to common stockholders	$	772.9		$	773.6		$	619.7		$	605.3
	Earnings per common share
	Basic earnings per common share	$	2.6		$	2.6		$	1.97		$	1.92
	Diluted earnings per common share	$	2.57		$	2.58		$	1.95		$	1.91
		For the three months						For the three months						For the three months						For the three months
		ended						ended						ended						ended
		March 31, 2012						June 30, 2012						September 30, 2012						December 31, 2012
		As originally			As adjusted			As originally			As adjusted			As originally			As adjusted			As originally			As adjusted
		reported						reported						reported						reported
		(in millions, except per share data)
	Revenues
	Premiums and other considerations	$	679.8		$	679.8		$	681.3		$	681.3		$	1,158.20		$	1,158.20		$	700.1		$	700.1
	Fees and other revenues		598			598			636.1			636.1			675			675			717.6			717.6
	Net investment income		824.8			824.8			801			801			783.8			783.8			845.3			845.3
	Net realized capital gains, excluding impairment losses on available-for-sale securities		22.1			22.1			32.2			32.2			122.1			122.1			56.3			56.3
	Total other-than-temporary impairment losses on available-for-sale securities		(33.7	)		(33.7	)		(49.1	)		(49.1	)		(43.6	)		(43.6	)		(9.5	)		(9.5	)
	Other-than-temporary impairment losses on fixed maturities, available-for- sale reclassified to (from) other comprehensive income		4.9			4.9			17.1			17.1			9.2			9.2			(13.9	)		(13.9	)
	Net impairment losses on available-for-sale securities		(28.8	)		(28.8	)		(32.0	)		(32.0	)		(34.4	)		(34.4	)		(23.4	)		(23.4	)
	Net realized capital gains (losses)		(6.7	)		(6.7	)		0.2			0.2			87.7			87.7			32.9			32.9
	Total revenues		2,095.90			2,095.90			2,118.60			2,118.60			2,704.70			2,704.70			2,295.90			2,295.90
	Expenses
	Benefits, claims and settlement expenses		1,212.50			1,212.50			1,110.00			1,110.00			1,647.00			1,647.00			1,154.40			1,154.40
	Dividends to policyholders		50.3			50.3			49.5			49.5			49.7			49.7			48.2			48.2
	Operating expenses		556			555.1			724.1			729.6			826.6			816.4			827.4			832.4
	Total expenses		1,818.80			1,817.90			1,883.60			1,889.10			2,523.30			2,513.10			2,030.00			2,035.00
	Income before income taxes		277.1			278			235			229.5			181.4			191.6			265.9			260.9
	Income taxes (benefits)		58.2			56.7			50.9			50.9			(9.9	)		(7.2	)		35.5			34.2
	Net income		218.9			221.3			184.1			178.6			191.3			198.8			230.4			226.7
	Net income attributable to noncontrolling interest		9.2			9.2			2.7			2.7			3.4			3.4			3.5			3.5
	Net income attributable to Principal Financial Group, Inc.		209.7			212.1			181.4			175.9			187.9			195.4			226.9			223.2
	Preferred stock dividends		8.2			8.2			8.3			8.3			8.2			8.2			8.3			8.3
	Net income available to common stockholders	$	201.5		$	203.9		$	173.1		$	167.6		$	179.7		$	187.2		$	218.6		$	214.9
	Earnings per common share
	Basic earnings per common share	$	0.67		$	0.68		$	0.58		$	0.56		$	0.61		$	0.64		$	0.74		$	0.72
	Diluted earnings per common share	$	0.66		$	0.68		$	0.58		$	0.56		$	0.6		$	0.63		$	0.74		$	0.72
Effects of Deferred Acquisition Cost Accounting Change on Prior Period Consolidated Statements of Comprehensive Income (Table)	'
		For the year ended						For the year ended
		December 31, 2012						December 31, 2011
		As originally			As adjusted			As originally			As adjusted
		reported						reported
		(in millions)
	Net income	$	824.7		$	825.4		$	688.9		$	674.5
	Other comprehensive income (loss), net:
	Net unrealized gains on available-for-sale securities		557.6			557.6			208.6			208.6
	Noncredit component of impairment losses on fixed maturities, available-for-sale		(6.7	)		(6.7	)		31			31
	Net unrealized gains (losses) on derivative instruments		(43.6	)		(43.6	)		23.6			23.6
	Foreign currency translation adjustment		(4.8	)		(9.8	)		(139.5	)		(130.9	)
	Net unrecognized postretirement benefit obligation		(127.4	)		(127.4	)		(172.9	)		(172.9	)
	Other comprehensive income (loss)		375.1			370.1			(49.2	)		(40.6	)
	Comprehensive income		1,199.80			1,195.50			639.7			633.9
	Comprehensive income attributable to noncontrolling interest		20			20			35.7			35.7
	Comprehensive income attributable to Principal Financial Group, Inc.	$	1,179.80		$	1,175.50		$	604		$	598.2
Effects of Reinsurance on Premiums and Other Considerations and Policy and Contract Benefits (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Premiums and other considerations:
	Direct	$	3,524.80		$	3,554.10		$	3,205.60
	Assumed		2.5			2.6			3
	Ceded		(373.2	)		(337.3	)		(317.6	)
	Net premiums and other considerations	$	3,154.10		$	3,219.40		$	2,891.00
	Benefits, claims and settlement expenses:
	Direct	$	4,933.30		$	5,268.60		$	4,926.50
	Assumed		32.2			33.9			34
	Ceded		(281.9	)		(178.6	)		(343.9	)
	Net benefits, claims and settlement expenses	$	4,683.60		$	5,123.90		$	4,616.60

Acquisition_Tables

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2013
Acquisition	'
Fair Value of Net Assets Acquired (Table)	'
	A summary of the fair values of the net assets acquired as of February 4, 2013, based upon current valuation estimates, is as follows (in millions):
	Assets
	Equity securities, available-for-sale	$	3.2
	Equity securities, trading		340.5
	Real estate		1.9
	Other investments		24.2
	Cash and cash equivalents		3.5
	Premiums due and other receivables		1.4
	Property and equipment		19.6
	Goodwill		631.8
	Other intangibles		671.3
	Separate account assets		33,919.40
	Other assets		27.3
	Total assets		35,644.10
	Liabilities
	Short-term debt		5
	Long-term debt		114.6
	Separate account liabilities		33,919.40
	Other liabilities		228
	Total liabilities		34,267.00
	Noncontrolling interest		113.6
	Net assets acquired	$	1,263.50
Pro Forma Consolidated Results of Operations (Table)	'
		For the year ended
		December 31,
		2013		2012		2011
		(in millions,
		except per share data)
	Total revenues	$	9,339.40	$	9,424.40	$	8,840.30
	Net income		956.6		939.3		753.2
	Basic earnings per common share		3.25		3.16		2.39
	Diluted earnings per common share		3.21		3.13		2.37
Results of Operations of Acquiree (Table)	'
		For the year ended,
		December 31, 2013
	Total revenues	$	186.4
	Net income		87

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Other Intangible Assets	'
Goodwill (Table)	'
		Retirement			Principal		Principal			U.S.			Corporate		Consolidated
		and Investor			Global		International			Insurance
		Services			Investors					Solutions
		(in millions)
	Balance at January 1, 2012	$	72.6		$	237	$	127.8		$	44.9		$	—	$	482.3
	Goodwill from acquisitions		—			—		63.3			10.5			—		73.8
	Foreign currency		—			2.9		(11.6	)		—			—		(8.7	)
	Other		(4.0	)		—		—			—			—		(4.0	)
	Balance at December 31, 2012		68.6			239.9		179.5			55.4			—		543.4
	Goodwill from acquisitions		—			—		631.8			2.6			—		634.4
	Goodwill disposed		—			—		—			(1.4	)		—		(1.4	)
	Foreign currency		—			1.2		(81.3	)		—			—		(80.1	)
	Other		4			—		—			—			—		4
	Balance at December 31, 2013	$	72.6		$	241.1	$	730		$	56.6		$	—	$	1,100.30
Finite Lived Intangible Assets (Table)	'
		December 31,
		2013								2012
		Gross			Accumulated		Net			Gross			Accumulated		Net
		carrying			amortization		carrying			carrying			amortization		carrying
		value					value			value					value
		(in millions)
	Present value of future profits	$	13.5		$	6.7	$	6.8		$	13.5		$	6.1	$	7.4
	Other finite lived intangible assets		858.8			262.9		595.9			436.1			224.1		212
	Total amortized intangible assets	$	872.3		$	269.6	$	602.7		$	449.6		$	230.2	$	219.4
Other Finite Lived Intangible Assets Estimated Amortization Expense (Table)	'
	At December 31, 2013, the estimated amortization expense for the next five years is as follows (in millions):
	Year ending December 31:
	2014	$	52.3
	2015		50.9
	2016		50.1
	2017		49.2
	2018		48

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2013
Variable Interest Entities	'
Carrying Amounts of Assets and Liabilities of Consolidated Variable Interest Entities (Table)	'
		Grantor trusts		Collateralized		CMBS		Mandatory		Total
				private investment				retirement
				vehicle				savings
		(in millions)
	December 31, 2013
	Fixed maturities, available-for-sale	$	272	$	—	$	—	$	—	$	272
	Fixed maturities, trading		—		110.4		—		—		110.4
	Equity securities, trading		—		—		—		327.2		327.2
	Other investments		—		—		68.1		—		68.1
	Accrued investment income		0.3		—		0.6		—		0.9
	Separate account assets		—		—		—		32,824.70		32,824.70
	Total assets	$	272.3	$	110.4	$	68.7	$	33,151.90	$	33,603.30
	Deferred income taxes	$	1.5	$	—	$	—	$	—	$	1.5
	Separate account liabilities		—		—		—		32,824.70		32,824.70
	Other liabilities (1)		217.2		93.8		31.4		—		342.4
	Total liabilities	$	218.7	$	93.8	$	31.4	$	32,824.70	$	33,168.60
	December 31, 2012
	Fixed maturities, available-for-sale	$	194.6	$	—	$	—	$	—	$	194.6
	Fixed maturities, trading		—		110.4		—		—		110.4
	Equity securities, trading		—		—		—		—		—
	Other investments		—		—		80.3		—		80.3
	Accrued investment income		0.5		—		0.6		—		1.1
	Total assets	$	195.1	$	110.4	$	80.9	$	—	$	386.4
	Deferred income taxes	$	1.8	$	—	$	—	$	—	$	1.8
	Other liabilities (1)		152.4		104.8		45.7		—		302.9
	Total liabilities	$	154.2	$	104.8	$	45.7	$	—	$	304.7
	-1
	Grantor trusts contain an embedded derivative of a forecasted transaction to deliver the underlying securities; the collateralized private investment vehicle includes derivative liabilities and an obligation to redeem notes at maturity or termination of the trust; and CMBS includes an obligation to the bondholders.
Asset Carrying Value and Maximum Loss Exposure of Unconsolidated Variable Interest Entities (Table)	'
		Asset carrying value		Maximum exposure to
				loss (1)
		(in millions)
	December 31, 2013
	Fixed maturities, available-for-sale:
	Corporate	$	523.4	$	448.2
	Residential mortgage-backed pass-through securities		2,845.20		2,799.10
	Commercial mortgage-backed securities		4,026.40		4,078.00
	Collateralized debt obligations		363.4		391.9
	Other debt obligations		4,167.80		4,157.50
	Fixed maturities, trading:
	Residential mortgage-backed pass-through securities		47.5		47.5
	Commercial mortgage-backed securities		1.8		1.8
	Collateralized debt obligations		59.6		59.6
	Other debt obligations		1.2		1.2
	Other investments:
	Other limited partnership interests		123.5		123.5
	December 31, 2012
	Fixed maturities, available-for-sale:
	Corporate	$	523.2	$	403.7
	Residential mortgage-backed pass-through securities		3,226.70		3,022.70
	Commercial mortgage-backed securities		3,897.40		4,094.80
	Collateralized debt obligations		379.2		428.8
	Other debt obligations		3,779.20		3,756.90
	Fixed maturities, trading:
	Residential mortgage-backed pass-through securities		77.7		77.7
	Commercial mortgage-backed securities		2.8		2.8
	Collateralized debt obligations		56.4		56.4
	Other debt obligations		3.2		3.2
	Other investments:
	Other limited partnership interests		136.2		136.2
	-1
	Our risk of loss is limited to our initial investment measured at amortized cost for fixed maturities, available-for-sale and other investments. Our risk of loss is limited to our investment measured at fair value for our fixed maturities, trading.

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Investments	'
Fixed Maturities and Equity Securities Available-for-Sale (Table)	'
		Amortized			Gross			Gross			Fair value			Other-than-
		cost			unrealized			unrealized						temporary
					gains			losses						impairments in
														AOCI (1)
		(in millions)
	December 31, 2013
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	818.2		$	12.7		$	50.4		$	780.5		$	—
	Non-U.S. government and agencies		853.2			148.8			5.2			996.8			—
	States and political subdivisions		3,622.80			120.9			85.7			3,658.00			—
	Corporate		30,280.60			1,958.80			320.4			31,919.00			17.1
	Residential mortgage-backed pass-through securities		2,799.10			92.8			46.7			2,845.20			—
	Commercial mortgage-backed securities		4,078.00			170.6			222.2			4,026.40			183.4
	Collateralized debt obligations		391.9			6			34.5			363.4			0.7
	Other debt obligations		4,157.50			51.8			41.5			4,167.80			76.3
	Total fixed maturities, available-for-sale	$	47,001.30		$	2,562.40		$	806.6		$	48,757.10		$	277.5
	Total equity securities, available-for-sale	$	113.8		$	10		$	13.3		$	110.5
	December 31, 2012
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	911.4		$	33.2		$	0.3		$	944.3		$	—
	Non-U.S. government and agencies		944.9			264.3			0.9			1,208.30			—
	States and political subdivisions		2,940.40			241.1			2.7			3,178.80			—
	Corporate		31,615.40			3,029.90			319.9			34,325.40			19.5
	Residential mortgage-backed pass-through securities		3,022.70			204.4			0.4			3,226.70			—
	Commercial mortgage-backed securities		4,094.80			241.7			439.1			3,897.40			195.4
	Collateralized debt obligations		428.8			7			56.6			379.2			4.3
	Other debt obligations		3,756.90			73.5			51.2			3,779.20			82.8
	Total fixed maturities, available-for-sale	$	47,715.30		$	4,095.10		$	871.1		$	50,939.30		$	302
	Total equity securities, available-for-sale	$	132.4		$	12.6		$	8.5		$	136.5
	-1
	Excludes $148.6 million and $95.0 million as of December 31, 2013 and December 31, 2012, respectively, 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			Fair
		cost			value
		(in millions)
	Due in one year or less	$	2,977.30		$	3,019.00
	Due after one year through five years		12,674.40			13,297.30
	Due after five years through ten years		8,669.80			9,091.20
	Due after ten years		11,253.30			11,946.80
	Subtotal		35,574.80			37,354.30
	Mortgage-backed and other asset-backed securities		11,426.50			11,402.80
	Total	$	47,001.30		$	48,757.10
Net Investment Income (Table)	'
		For the year ended December 31,
		2013			2012			2011
		(in millions)
	Fixed maturities, available-for-sale	$	2,321.30		$	2,454.80		$	2,596.20
	Fixed maturities, trading		22.5			30.2			64.7
	Equity securities, available-for-sale		7.6			8.6			10.5
	Equity securities, trading		19.8			6.6			4.4
	Mortgage loans		611.5			635.8			649.2
	Real estate		61.2			71.4			74.2
	Policy loans		49.9			53.7			58.2
	Cash and cash equivalents		14			9.6			8.5
	Derivatives		(115.2	)		(131.2	)		(196.1	)
	Other		222			196.6			188.5
	Total		3,214.60			3,336.10			3,458.30
	Investment expenses		(76.2	)		(81.2	)		(83.0	)
	Net investment income	$	3,138.40		$	3,254.90		$	3,375.30
Net Realized Capital Gains and Losses (Table)	'
		For the year ended December 31,
		2013			2012			2011
		(in millions)
	Fixed maturities, available-for-sale:
	Gross gains	$	45.5		$	31		$	26.4
	Gross losses		(122.1	)		(144.9	)		(158.8	)
	Other-than-temporary impairment losses reclassified to (from) OCI		(24.5	)		17.3			(49.7	)
	Hedging, net		(115.5	)		(27.5	)		130.5
	Fixed maturities, trading		(7.1	)		2.2			(6.7	)
	Equity securities, available-for-sale:
	Gross gains		0.8			0.6			2.2
	Gross losses		(0.3	)		(0.9	)		(6.4	)
	Equity securities, trading		26.9			34.1			20.3
	Mortgage loans		(15.8	)		(51.3	)		(42.1	)
	Derivatives		(23.0	)		(10.9	)		(180.5	)
	Other		9.9			264.4			142.5
	Net realized capital gains (losses)	$	(225.2	)	$	114.1		$	(122.3	)
Other-Than-Temporary Impairment Losses, Net of Recoveries (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Fixed maturities, available-for-sale	$	(91.2	)	$	(135.5	)	$	(143.8	)
	Equity securities, available-for-sale		(0.3	)		(0.4	)		(3.8	)
	Total other-than-temporary impairment losses, net of recoveries from the sale of previously impaired securities		(91.5	)		(135.9	)		(147.6	)
	Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) OCI (1)		(24.5	)		17.3			(49.7	)
	Net impairment losses on available-for-sale securities	$	(116.0	)	$	(118.6	)	$	(197.3	)
	-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,
		2013			2012			2011
		(in millions)
	Beginning balance	$	(335.2	)	$	(434.8	)	$	(325.7	)
	Credit losses for which an other-than-temporary impairment was not previously recognized		(15.1	)		(20.7	)		(37.8	)
	Credit losses for which an other-than-temporary impairment was previously recognized		(75.9	)		(80.0	)		(135.6	)
	Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold		177.6			191.9			68.2
	Net reduction (increase) for positive changes in cash flows expected to be collected and amortization (1)		12.6			8.4			(3.9	)
	Ending balance	$	(236.0	)	$	(335.2	)	$	(434.8	)
	(1)Amounts are recognized in net investment income.
Gross Unrealized Losses for Fixed Maturities and Equity Securities (Table)	'
		December 31, 2013
		Less than twelve						Greater than or						Total
		months						equal to twelve
								months
		Fair			Gross			Fair			Gross			Fair		Gross
		value			unrealized			value			unrealized			value		unrealized
					losses						losses					losses
		(in millions)
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	526.8		$	49.6		$	9.2		$	0.8		$	536	$	50.4
	Non-U.S. governments		78.1			5.1			5.8			0.1			83.9		5.2
	States and political subdivisions		1,338.60			75.3			46.1			10.4			1,384.70		85.7
	Corporate		4,087.90			155.4			1,278.10			165			5,366.00		320.4
	Residential mortgage-backed pass- through securities		1,150.30			38.2			85.9			8.5			1,236.20		46.7
	Commercial mortgage-backed securities		683.7			15.3			495.6			206.9			1,179.30		222.2
	Collateralized debt obligations		88.8			1.4			47.4			33.1			136.2		34.5
	Other debt obligations		1,359.00			16.1			287.9			25.4			1,646.90		41.5
	Total fixed maturities, available-for-sale	$	9,313.20		$	356.4		$	2,256.00		$	450.2		$	11,569.20	$	806.6
	Total equity securities, available-for-sale	$	16.7		$	0.3		$	48.3		$	13		$	65	$	13.3
		December 31, 2012
		Less than twelve						Greater than or						Total
		months						equal to twelve
								months
		Fair			Gross			Fair			Gross			Fair		Gross
		value			unrealized			value			unrealized			value		unrealized
					losses						losses					losses
		(in millions)
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	115.4		$	0.3		$	—		$	—		$	115.4	$	0.3
	Non-U.S. governments		17.3			0.2			13.4			0.7			30.7		0.9
	States and political subdivisions		235.3			2.1			8.8			0.6			244.1		2.7
	Corporate		831.8			10.6			1,961.70			309.3			2,793.50		319.9
	Residential mortgage-backed pass- through securities		70.4			0.3			2.4			0.1			72.8		0.4
	Commercial mortgage-backed securities		98.9			3.3			785			435.8			883.9		439.1
	Collateralized debt obligations		72.2			1			133.8			55.6			206		56.6
	Other debt obligations		235.6			2			414.9			49.2			650.5		51.2
	Total fixed maturities, available-for-sale	$	1,676.90		$	19.8		$	3,320.00		$	851.3		$	4,996.90	$	871.1
	Total equity securities, available-for-sale	$	5.8		$	0.1		$	52.9		$	8.4		$	58.7	$	8.5
Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments (Table)	'
		December 31, 2013			December 31, 2012
		(in millions)
	Net unrealized gains on fixed maturities, available-for-sale (1)	$	2,064.00		$	3,562.50
	Noncredit component of impairment losses on fixed maturities, available-for-sale		(277.5	)		(302.0	)
	Net unrealized gains (losses) on equity securities, available-for-sale		(3.3	)		4.1
	Adjustments for assumed changes in amortization patterns		(265.9	)		(515.2	)
	Adjustments for assumed changes in policyholder liabilities		(602.5	)		(1,198.7	)
	Net unrealized gains on derivative instruments		56			90.7
	Net unrealized gains on equity method subsidiaries and noncontrolling interest adjustments		71.8			191.3
	Provision for deferred income taxes		(342.0	)		(597.0	)
	Net unrealized gains on available-for-sale securities and derivative instruments	$	700.6		$	1,235.70
	-1
	Excludes net unrealized gains (losses) on fixed maturities, available-for-sale included in fair value hedging relationships.
Mortgage Loans (Table)	'
		December 31, 2013			December 31, 2012
		(in millions)
	Commercial mortgage loans	$	10,327.70		$	10,235.10
	Residential mortgage loans		1,275.70			1,382.00
	Total amortized cost		11,603.40			11,617.10
	Valuation allowance		(69.8	)		(97.4	)
	Total carrying value	$	11,533.60		$	11,519.70
Commercial Mortgage Loans by Geographic Distribution and Property Type Distribution (Table)	'
		December 31, 2013						December 31, 2012
		Amortized			Percent			Amortized			Percent
		cost			of total			cost			of total
		($ in millions)
	Geographic distribution
	New England	$	528.5			5.1	%	$	536.6			5.2	%
	Middle Atlantic		2,489.00			24.1			2,233.40			21.8
	East North Central		519.9			5			635.6			6.2
	West North Central		302.9			2.9			377.3			3.7
	South Atlantic		1,949.50			18.9			2,135.00			20.9
	East South Central		192.8			1.9			244.8			2.4
	West South Central		830.3			8			767.9			7.5
	Mountain		747.1			7.2			726.6			7.1
	Pacific		2,722.50			26.5			2,562.30			25
	International		45.2			0.4			15.6			0.2
	Total	$	10,327.70			100	%	$	10,235.10			100	%
	Property type distribution
	Office	$	3,360.50			32.6	%	$	3,078.80			30.1	%
	Retail		2,668.50			25.8			2,928.30			28.6
	Industrial		1,766.20			17.1			1,765.50			17.2
	Apartments		1,911.20			18.5			1,685.90			16.5
	Hotel		333.1			3.2			445.8			4.4
	Mixed use/other		288.2			2.8			330.8			3.2
	Total	$	10,327.70			100	%	$	10,235.10			100	%
Commercial Mortgage Loan Portfolio by Credit Risk (Table)	'
		December 31, 2013
		Brick and mortar			CTL			Total
		(in millions)
	A- and above	$	8,091.90		$	194.5		$	8,286.40
	BBB+ thru BBB-		1,463.70			250			1,713.70
	BB+ thru BB-		155.4			0.1			155.5
	B+ and below		170.1			2			172.1
	Total	$	9,881.10		$	446.6		$	10,327.70
		December 31, 2012
		Brick and mortar			CTL			Total
		(in millions)
	A- and above	$	7,257.70		$	231.3		$	7,489.00
	BBB+ thru BBB-		1,804.50			294.9			2,099.40
	BB+ thru BB-		266.8			1.6			268.4
	B+ and below		376			2.3			378.3
	Total	$	9,705.00		$	530.1		$	10,235.10
Performing and Non-Performing Residential Mortgage Loans (Table)	'
		December 31, 2013
		Home equity			First liens			Total
		(in millions)
	Performing	$	378.3		$	862.1		$	1,240.40
	Nonperforming		16.6			18.7			35.3
	Total	$	394.9		$	880.8		$	1,275.70
		December 31, 2012
		Home equity			First liens			Total
		(in millions)
	Performing	$	472.6		$	865		$	1,337.60
	Nonperforming		23.1			21.3			44.4
	Total	$	495.7		$	886.3		$	1,382.00
Non-Accrual Mortgage Loans (Table)	'
		December 31, 2013			December 31, 2012
		(in millions)
	Commercial:
	Brick and mortar	$	33.2		$	44.5
	Residential:
	Home equity		16.6			23.1
	First liens		11.4			13.2
	Total	$	61.2		$	80.8
Mortgage Loans Aging (Table)	'
		December 31, 2013
		30 - 59 days			60 - 89 days			90 days or			Total			Current		Total		Recorded
		past due			past due			more past			past due					loans		investment
								due										90 days or
																		more and
																		accruing
		(in millions)
	Commercial-brick and mortar	$	—		$	—		$	16.7		$	16.7		$	9,864.40	$	9,881.10	$	—
	Commercial-CTL		—			—			—			—			446.6		446.6		—
	Residential-home equity		4.4			1			3			8.4			386.5		394.9		—
	Residential-first liens		32.4			7.4			17.1			56.9			823.9		880.8		7.3
	Total	$	36.8		$	8.4		$	36.8		$	82		$	11,521.40	$	11,603.40	$	7.3
		December 31, 2012
		30 - 59 days			60 - 89 days			90 days or			Total past due			Current		Total		Recorded
		past due			past due			more past								loans		investment
								due										90 days or
																		more and
																		accruing
		(in millions)
	Commercial-brick and mortar	$	32.8		$	13.7		$	—		$	46.5		$	9,658.50	$	9,705.00	$	—
	Commercial-CTL		—			—			—			—			530.1		530.1		—
	Residential-home equity		5.7			2.8			3.9			12.4			483.3		495.7		—
	Residential-first liens		22.3			5.1			19.8			47.2			839.1		886.3		8.1
	Total	$	60.8		$	21.6		$	23.7		$	106.1		$	11,511.00	$	11,617.10	$	8.1
Mortgage Loan Valuation Allowance (Table)	'
		Commercial			Residential			Total
		(in millions)
	For the year ended December 31, 2013
	Beginning balance	$	51.8		$	45.6		$	97.4
	Provision		4.1			10.8			14.9
	Charge-offs		(28.0	)		(18.3	)		(46.3	)
	Recoveries		0.8			3.1			3.9
	Effect of exchange rates		—			(0.1	)		(0.1	)
	Ending balance	$	28.7		$	41.1		$	69.8
	Allowance ending balance by basis of impairment method:
	Individually evaluated for impairment	$	2.4		$	10.2		$	12.6
	Collectively evaluated for impairment		26.3			30.9			57.2
	Allowance ending balance	$	28.7		$	41.1		$	69.8
	Loan balance by basis of impairment method:
	Individually evaluated for impairment	$	4.4		$	33		$	37.4
	Collectively evaluated for impairment		10,323.30			1,242.70			11,566.00
	Loan ending balance	$	10,327.70		$	1,275.70		$	11,603.40
	For the year ended December 31, 2012
	Beginning balance	$	64.8		$	37.3		$	102.1
	Provision		13.5			39.7			53.2
	Charge-offs		(26.7	)		(35.1	)		(61.8	)
	Recoveries		0.2			3.6			3.8
	Effect of exchange rates		—			0.1			0.1
	Ending balance	$	51.8		$	45.6		$	97.4
	Allowance ending balance by basis of impairment method:
	Individually evaluated for impairment	$	2.4		$	10.4		$	12.8
	Collectively evaluated for impairment		49.4			35.2			84.6
	Allowance ending balance	$	51.8		$	45.6		$	97.4
	Loan balance by basis of impairment method:
	Individually evaluated for impairment	$	13.6		$	39.7		$	53.3
	Collectively evaluated for impairment		10,221.50			1,342.30			11,563.80
	Loan ending balance	$	10,235.10		$	1,382.00		$	11,617.10
	For the year ended December 31, 2011
	Beginning balance	$	80.6		$	40.5		$	121.1
	Provision		17			27.2			44.2
	Charge-offs		(32.9	)		(33.4	)		(66.3	)
	Recoveries		0.1			3.2			3.3
	Effect of exchange rates		—			(0.2	)		(0.2	)
	Ending balance	$	64.8		$	37.3		$	102.1
	Allowance ending balance by basis of impairment method:
	Individually evaluated for impairment	$	16.3		$	3.2		$	19.5
	Collectively evaluated for impairment		48.5			34.1			82.6
	Allowance ending balance	$	64.8		$	37.3		$	102.1
	Loan balance by basis of impairment method:
	Individually evaluated for impairment	$	114		$	27.4		$	141.4
	Collectively evaluated for impairment		9,347.40			1,340.50			10,687.90
	Loan ending balance	$	9,461.40		$	1,367.90		$	10,829.30
Impaired Mortgage Loans (Table)	'
		December 31, 2013
		Recorded			Unpaid			Related
		investment			principal			allowance
					balance
		(in millions)
	With no related allowance recorded:
	Commercial-brick and mortar	$	21.5		$	32.7		$	—
	Residential-first liens		4.6			4.6			—
	With an allowance recorded:
	Commercial-brick and mortar		4.4			4.4			2.4
	Residential-home equity		19.5			19.7			9.2
	Residential-first liens		8.9			7.8			1
	Total:
	Commercial	$	25.9		$	37.1		$	2.4
	Residential	$	33		$	32.1		$	10.2
		Average			Interest income
		recorded			recognized
		investment
		(in millions)
	For the year ended December 31, 2013
	With no related allowance recorded:
	Commercial-brick and mortar	$	22.2		$	0.2
	Residential-first liens		7.2			—
	With an allowance recorded:
	Commercial-brick and mortar		4.4			0.3
	Residential-home equity		20.2			1.1
	Residential-first liens		8.9			0.2
	Total:
	Commercial	$	26.6		$	0.5
	Residential	$	36.3		$	1.3
	For the year ended December 31, 2012
	With no related allowance recorded:
	Commercial-brick and mortar	$	11.4		$	2.6
	Residential-first liens		7			—
	With an allowance recorded:
	Commercial-brick and mortar		59.2			0.2
	Residential-home equity		17.7			0.9
	Residential-first liens		9			0.1
	Total:
	Commercial	$	70.6		$	2.8
	Residential	$	33.7		$	1
	For the year ended December 31, 2011
	With no related allowance recorded:
	Commercial-brick and mortar	$	11.3		$	0.9
	Residential-first liens		4.4			—
	With an allowance recorded:
	Commercial-brick and mortar		79			1
	Residential-home equity		12.6			0.8
	Residential-first liens		9.6			0.2
	Total:
	Commercial	$	90.3		$	1.9
	Residential	$	26.6		$	1
Mortgage Loans Modified as a Troubled Debt Restructuring (Table)	'
		For the year ended December 31, 2013
		TDRs						TDRs in payment default
		Number of			Recorded			Number of			Recorded
		contracts			investment			contracts			investment
					(in millions)						(in millions)
	Commercial-brick and mortar		2		$	0.9			—		$	—
	Residential-home equity		69			3.8			19			—
	Residential-first liens		3			0.6			1			0.3
	Total		74		$	5.3			20		$	0.3
		For the year ended December 31, 2012
		TDRs						TDRs in payment default
		Number of			Recorded			Number of			Recorded
		contracts			investment			contracts			investment
					(in millions)						(in millions)
	Commercial-brick and mortar		2		$	18			1		$	13.7
	Residential-home equity		324			15			12			—
	Residential-first liens		12			2.1			—			—
	Total		338		$	35.1			13		$	13.7
		For the year ended December 31, 2011
		TDRs						TDRs in payment default
		Number of			Recorded			Number of			Recorded
		contracts			investment			contracts			investment
					(in millions)						(in millions)
	Commercial-brick and mortar		1		$	4.4			1		$	4.4
	Residential-home equity		151			7.9			6			—
	Residential-first liens		7			1.6			1			0.3
	Total		159		$	13.9			8		$	4.7
Minority Interests in Unconsolidated Entities-Balance Sheet (Table)	'
		December 31,
		2013			2012
		(in millions)
	Total assets	$	47,401.90		$	46,036.20
	Total liabilities		39,588.00			38,080.90
	Total equity	$	7,813.90		$	7,955.30
	Net investment in unconsolidated entities (1)	$	1,098.60		$	1,100.60
	-1
	Primarily relates to Brasilprev Seguros e Previdencia, a co-managed joint venture in Brazil, which is reported in the results of our Principal International segment.
Minority Interests in Unconsolidated Entities-Income Statement (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Total revenues	$	3,002.90		$	4,555.90		$	5,574.60
	Total expenses		2,253.20			3,774.50			4,849.80
	Net income		738.6			750.1			719.3
	Our share of net income of unconsolidated entities (1)		133.4			120.1			116.5
	-1
	Primarily relates to Brasilprev Seguros e Previdencia, a co-managed joint venture in Brazil, which is reported in the results of our Principal International segment.
Financial Assets Subject to Netting Agreements (Table)	'
					Gross amounts not offset in
					the Statement of Financial
					Position
		Gross amount			Financial			Collateral			Net amount
		of recognized			instruments (2)			received
		assets (1)
		(in millions)
	December 31, 2013
	Derivative assets	$	664.9		$	(581.5	)	$	(82.1	)	$	1.3
	Reverse repurchase agreements		51.8			—			(51.8	)		—
	Total	$	716.7		$	(581.5	)	$	(133.9	)	$	1.3
	December 31, 2012
	Derivative assets	$	1,016.30		$	(779.3	)	$	(225.5	)	$	11.5
	Reverse repurchase agreements		148.2			—			(148.2	)		—
	Total	$	1,164.50		$	(779.3	)	$	(373.7	)	$	11.5
	-1
	The gross amount of recognized derivative and reverse repurchase agreement assets are reported with other investments on the consolidated statements of financial position. The above excludes $0.2 million and $0.4 million of derivative assets as of December 31, 2013 and December 31, 2012, 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 Statement of Financial
					Position
		Gross amount			Financial			Collateral			Net amount
		of recognized			instruments (2)			pledged
		liabilities (1)
		(in millions)
	December 31, 2013
	Derivative liabilities	$	1,022.00		$	(581.5	)	$	(362.1	)	$	78.4
	December 31, 2012
	Derivative liabilities	$	1,198.20		$	(779.3	)	$	(279.1	)	$	139.8
	-1
	The gross amount of recognized derivative liabilities are reported with other liabilities and contractholder funds on the consolidated statements of financial position. The above excludes $226.7 million and $329.8 million of derivative liabilities as of December 31, 2013 and December 31, 2012, respectively, which are primarily embedded derivatives that are not subject to master netting agreements or similar agreements. The gross amount of recognized repurchase agreement liabilities are reported with short-term debt on the consolidated statements of financial position. The gross amounts of derivative and repurchase agreement 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_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Derivative Financial Instruments	'
Derivative Financial Instruments, Exposure (Table)	'
		December 31, 2013			December 31, 2012
		(in millions)
	Notional amounts of derivative instruments
	Interest rate contracts:
	Interest rate swaps	$	20,570.80		$	18,381.20
	Interest rate options		4,100.00			500
	Swaptions		325			325
	Interest rate futures		92.5			82
	Foreign exchange contracts:
	Currency swaps		2,367.50			3,454.10
	Currency forwards		247.4			557.2
	Currency options		—			1,400.00
	Equity contracts:
	Equity options		2,010.40			1,811.80
	Equity futures		273.3			373.6
	Credit contracts:
	Credit default swaps		1,153.20			1,378.30
	Total return swaps		90			100
	Futures		9.1			—
	Other contracts:
	Embedded derivative financial instruments		7,601.10			5,893.20
	Total notional amounts at end of period	$	38,840.30		$	34,256.40
	Credit exposure of derivative instruments
	Interest rate contracts:
	Interest rate swaps	$	435.5		$	683.9
	Interest rate options		42.5			48.5
	Swaptions		1			0.7
	Foreign exchange contracts:
	Currency swaps		200.9			263.8
	Currency forwards		0.6			6.8
	Currency options		—			1.9
	Equity contracts:
	Equity options		30			74.3
	Credit contracts:
	Credit default swaps		9.5			6.8
	Total return swaps		0.1			—
	Total gross credit exposure		720.1			1,086.70
	Less: collateral received		115.9			248
	Net credit exposure	$	604.2		$	838.7
Derivative Financial Instruments, Fair Value Disclosures (Table)	'
		Derivative assets (1)						Derivative liabilities (2)
		December 31, 2013			December 31, 2012			December 31, 2013			December 31, 2012
		(in millions)
	Derivatives designated as hedging instruments
	Interest rate contracts	$	0.1		$	10.3		$	285.4		$	440.5
	Foreign exchange contracts		121.6			190			51.2			127.2
	Total derivatives designated as hedging instruments	$	121.7		$	200.3		$	336.6		$	567.7
	Derivatives not designated as hedging instruments
	Interest rate contracts	$	452.2		$	677.1		$	489.6		$	493.9
	Foreign exchange contracts		51.6			58.2			17.9			14.3
	Equity contracts		30			74.3			145			27.7
	Credit contracts		9.6			6.8			35.5			96.6
	Other contracts		—			—			224.1			327.8
	Total derivatives not designated as hedging instruments		543.4			816.4			912.1			960.3
	Total derivative instruments	$	665.1		$	1,016.70		$	1,248.70		$	1,528.00
	-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 derivative liabilities with a fair value of $6.9 million and $170.5 million as of December 31, 2013 and December 31, 2012, respectively, are reported with contractholder funds on the consolidated statements of financial position.
Credit Derivatives Sold (Table)	'
		December 31, 2013
		Notional			Fair			Maximum			Weighted
		amount			value			future			average
								payments			expected life
											(in years)
		(in millions)
	Single name credit default swaps
	Corporate debt
	AAA	$	10		$	0.3		$	10			4.7
	AA		84			1.8			84			4
	A		294.5			4.2			294.5			4
	BBB		265			(1.2	)		265			3.9
	Total single name credit default swaps		653.5			5.1			653.5			4
	Basket and index credit default swaps
	Corporate debt
	Near default (1)		110.4			(19.9	)		110.4			3.2
	Government/municipalities
	AA		30			(3.5	)		30			3.7
	Structured finance
	BBB		25			(0.9	)		25			3.5
	Total basket and index credit default swaps		165.4			(24.3	)		165.4			3.4
	Total credit default swap protection sold	$	818.9		$	(19.2	)	$	818.9			3.9
		December 31, 2012
		Notional			Fair			Maximum			Weighted
		amount			value			future			average
								payments			expected life
											(in years)
		(in millions)
	Single name credit default swaps
	Corporate debt
	AA	$	70		$	(0.2	)	$	70			2.5
	A		572			2.4			572			2.4
	BBB		200			(1.6	)		200			3
	Structured finance
	Near default		11.1			(11.0	)		11.1			8.5
	Total single name credit default swaps		853.1			(10.4	)		853.1			2.6
	Basket and index credit default swaps
	Corporate debt
	Near default (1)		110.4			(65.2	)		110.4			4.2
	Government/municipalities
	AA		30			(7.3	)		30			4.7
	Structured finance
	BBB		25			(5.6	)		25			4.5
	Total basket and index credit default swaps		165.4			(78.1	)		165.4			4.4
	Total credit default swap protection sold	$	1,018.50		$	(88.5	)	$	1,018.50			2.9
	-1
	Includes $88.0 million notional of derivatives in consolidated collateralized private investment vehicle VIEs where the credit risk is borne by third-party investors.
Hybrid Instruments (Table)	'
		December 31, 2013
		Amortized			Carrying			Weighted
		cost			value			average
								expected life
								(in years)
		(in millions)
	Corporate debt
	BBB	$	23.4		$	23.4			3
	Total corporate debt		23.4			23.4			3
	Structured finance
	A		18.1			16.7			4.8
	BB		5.5			5.5			3.3
	B		4.1			4.1			3.1
	CCC		23.5			23.5			4.8
	Total structured finance		51.2			49.8			4.5
	Total fixed maturities with credit derivatives	$	74.6		$	73.2			4
		December 31, 2012
		Amortized			Carrying			Weighted
		cost			value			average
								expected life
								(in years)
		(in millions)
	Corporate debt
	BBB	$	20.5		$	20.5			4
	B		25			24.9			0.5
	Total corporate debt		45.5			45.4			2.1
	Structured finance
	AA		4.6			4.6			17
	BB		39.6			37.5			2.9
	B		4			4			4.4
	CCC		17.7			17.7			6.4
	Total structured finance		65.9			63.8			4.9
	Total fixed maturities with credit derivatives	$	111.4		$	109.2			3.8
Fair Value Hedges (Table)	'
		Amount of gain (loss)											Amount of gain (loss)
		recognized in net income											recognized in net income
		on derivatives											on related hedged item
		for the year ended											for the year ended
	Derivatives in fair value	December 31, (1)									Hedged items in fair fair value		December 31, (1)
	hedging relationships	2013			2012			2011			hedging relationships		2013			2012			2011
		(in millions)											(in millions)
	Interest rate contracts	$	139.5		$	38.6		$	(108.5	)	Fixed maturities, available-for-sale		$	(133.3	)	$	(34.1	)	$	105.4
	Interest rate contracts		(0.7	)		—			(2.2	)	Investment-type insurance contracts			0.2			—			2.4
	Foreign exchange contracts		(0.2	)		0.7			1.1		Fixed maturities, available-for-sale			0.4			0.4			(1.3	)
	Foreign exchange contracts		(36.7	)		9.3			(25.6	)	Investment-type insurance contracts			36.5			(12.6	)		25.7
	Total	$	101.9		$	48.6		$	(135.2	)	Total		$	(96.2	)	$	(46.3	)	$	132.2
	-1
	The gain (loss) on both derivatives and hedged items in fair value relationships is reported in net realized capital gains (losses) on the consolidated statements of operations. The net amount represents the ineffective portion of our fair value hedges.
Fair Value Hedges, Periodic Settlements Disclosures (Table)	'
		Amount of gain (loss)
		for the year ended
		December 31,
	Hedged Item	2013			2012			2011
		(in millions)
	Fixed maturities, available-for-sale (1)	$	(120.7	)	$	(134.3	)	$	(158.9	)
	Investment-type insurance contracts (2)		33.2			37.1			44
	-1
	Reported in net investment income on the consolidated statements of operations.
	-2
	Reported in benefits, claims and settlement expenses on the consolidated statements of operations.
Cash Flow Hedges (Table)	'
				Amount of gain											Amount of gain
				(loss) recognized											(loss) reclassified
				in AOCI on											from AOCI on
				derivatives (effective											derivatives (effective
				portion) for the year									Location of gain (loss)		portion) for the year
				ended December 31,									reclassified from AOCI		ended December 31,
	Derivatives in cash flow												into net income
	hedging relationships	Related hedged item		2013			2012			2011			(effective portion)		2013			2012			2011
				(in millions)											(in millions)
	Interest rate contracts	Fixed maturities, available-for-sale		$	(80.5	)	$	16.2		$	107.1		Net investment income		$	11.7		$	8.9		$	7.2
													Net realized capital losses			—			—			(0.2	)
	Interest rate contracts	Investment-type insurance contracts			2.5			2.5			(1.0	)	Benefits, claims and settlement expenses			—			—			(0.8	)
	Interest rate contracts	Debt			—			—			—		Operating expense			(6.6	)		(5.9	)		(5.3	)
	Foreign exchange contracts	Fixed maturities, available-for-sale			(0.9	)		(27.9	)		29.9		Net realized capital losses			(16.7	)		(6.4	)		(20.4	)
	Foreign exchange contracts	Investment-type insurance contract			5			7.6			12.8		Benefits, claims and settlement expenses			—			—			(1.7	)
	Total			$	(73.9	)	$	(1.6	)	$	148.8		Total		$	(11.6	)	$	(3.4	)	$	(21.2	)
Cash Flow Hedges, Periodic Settlements Disclosures (Table)	'
		Amount of gain (loss)
		for the year ended
		December 31,
	Hedged Item	2013			2012			2011
		(in millions)
	Fixed maturities, available-for-sale (1)	$	7.7		$	8		$	9.3
	Investment-type insurance contracts (2)		(11.0	)		(13.4	)		(13.1	)
	-1
	Reported in net investment income on the consolidated statements of operations.
	-2
	Reported in benefits, claims and settlement expenses on the consolidated statements of operations.
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	2013			2012			2011
		(in millions)
	Interest rate contracts	$	(137.6	)	$	(7.9	)	$	93.3
	Foreign exchange contracts		(0.1	)		63.1			(34.1	)
	Equity contracts		(159.4	)		(100.5	)		55.2
	Credit contracts		40.6			11			(9.9	)
	Other contracts		154.4			37.3			(200.4	)
	Total	$	(102.1	)	$	3		$	(95.9	)

Closed_Block_Tables

Closed Block (Tables)	12 Months Ended
	Dec. 31, 2013
Closed Block	'
Closed Block Liabilities and Assets Designated to the Closed Block (Table)	'
		December 31, 2013			December 31, 2012
		(in millions)
	Closed Block liabilities
	Future policy benefits and claims	$	4,532.00		$	4,664.50
	Other policyholder funds		10.5			10.7
	Policyholder dividends payable		270.5			280.6
	Policyholder dividends obligation		111.6			131
	Deferred income taxes		2.2			—
	Other liabilities		24.7			31.3
	Total Closed Block liabilities		4,951.50			5,118.10
	Assets designated to the Closed Block
	Fixed maturities, available-for-sale		2,470.90			2,735.10
	Fixed maturities, trading		13.4			17
	Equity securities, available-for-sale		3.6			5.5
	Mortgage loans		828.6			719.4
	Policy loans		644.2			665.5
	Other investments		118.5			158
	Total investments		4,079.20			4,300.50
	Cash and cash equivalents		70.3			51.3
	Accrued investment income		49.5			52.5
	Premiums due and other receivables		11.7			13.2
	Deferred tax asset		66.2			39.2
	Other assets		2.2			—
	Total assets designated to the Closed Block		4,279.10			4,456.70
	Excess of Closed Block liabilities over assets designated to the Closed Block		672.4			661.4
	Amounts included in accumulated other comprehensive income		12.9			62.4
	Maximum future earnings to be recognized from Closed Block assets and liabilities	$	685.3		$	723.8
Closed Block Revenues and Expenses (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Revenues
	Premiums and other considerations	$	379.9		$	397.4		$	428.8
	Net investment income		207.7			222.8			238.2
	Net realized capital gains (losses)		(12.3	)		3.6			7.9
	Total revenues		575.3			623.8			674.9
	Expenses
	Benefits, claims and settlement expenses		320.1			325.7			370.7
	Dividends to policyholders		184.4			192.6			204.2
	Operating expenses		4.7			4.9			2.9
	Total expenses		509.2			523.2			577.8
	Closed Block revenues, net of Closed Block expenses, before income taxes		66.1			100.6			97.1
	Income taxes		21.1			32.6			31.2
	Closed Block revenues, net of Closed Block expenses and income taxes		45			68			65.9
	Funding adjustment charges		(6.5	)		(4.8	)		(5.3	)
	Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustment charges	$	38.5		$	63.2		$	60.6
Change in Maximum Future Earnings of the Closed Block (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Beginning of year	$	723.8		$	787		$	847.6
	End of year		685.3			723.8			787
	Change in maximum future earnings	$	(38.5	)	$	(63.2	)	$	(60.6	)

Deferred_Acquisition_Costs_Tab

Deferred Acquisition Costs (Tables)	12 Months Ended
	Dec. 31, 2013
Deferred Acquisition Costs	'
Deferred Acquisition Costs Rollforward (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Balance at beginning of year	$	2,590.00		$	2,358.10		$	2,442.20
	Cost deferred during the year		447			428.9			344.4
	Amortized to expense during the year (1)		(187.1	)		(94.9	)		(271.4	)
	Adjustment related to unrealized gains on available-for-sale securities and derivative instruments		227.1			(102.1	)		(157.1	)
	Balance at end of year	$	3,077.00		$	2,590.00		$	2,358.10
	-1
	Includes adjustments for revisions to estimated gross profits.

Insurance_Liabilities_Tables

Insurance Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Insurance Liabilities	'
Contractholder Funds (Table)	'
		December 31,
		2013		2012
		(in millions)
	Liabilities for investment-type insurance contracts:
	Liabilities for individual annuities	$	10,582.70	$	11,316.20
	GICs		10,858.30		10,943.10
	Funding agreements		7,642.90		9,077.10
	Other investment-type insurance contracts		832.6		787.2
	Total liabilities for investment-type insurance contracts		29,916.50		32,123.60
	Universal life and other reserves		6,041.80		5,662.90
	Total contractholder funds	$	35,958.30	$	37,786.50
Future Policy Benefits and Claims (Table)	'
		December 31,
		2013		2012		2011
		(in millions)
	Balance at beginning of year	$	1,066.00	$	1,006.90	$	1,061.80
	Incurred:
	Current year		712		711.8		1,074.00
	Prior years		1		9.7		(10.8	)
	Total incurred		713		721.5		1,063.20
	Payments:
	Current year		432.1		446.3		820.8
	Prior years		202.2		216.1		297.3
	Total payments		634.3		662.4		1,118.10
	Balance at end of year:
	Current year		279.9		265.5		253.2
	Prior years		864.8		800.5		753.7
	Total balance at end of year	$	1,144.70	$	1,066.00	$	1,006.90
	Amounts not included in the rollforward above:
	Claim adjustment expense liabilities	$	43.4	$	46.6	$	42.9
	Reinsurance recoverables for unpaid claims		260.1		239.1		204.7

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt	'
Short-Term Debt (Table)	'
		December 31,
		2013		2012
		(in millions)
	Line of credit	$	117.8	$	—
	Other recourse short-term debt		32.8		40.8
	Total short-term debt	$	150.6	$	40.8
Long-Term Debt (Table)	'
		December 31,
		2013		2012
		(in millions)
	3.76% notes payable, due 2015	$	—	$	92.7
	1.85% notes payable, due 2017		299.8		299.7
	8.875% notes payable, due 2019		350		350
	3.3% notes payable, due 2022		299		298.9
	3.125% notes payable, due 2023		299.6		299.6
	6.05% notes payable, due 2036		601.6		601.7
	4.625% notes payable, due 2042		299.5		299.5
	4.35% notes payable, due 2043		299.3		299.2
	8.0% surplus notes payable, due 2044		99.3		99.3
	Non-recourse mortgages and notes payable		53.3		30.7
	Total long-term debt	$	2,601.40	$	2,671.30
Future Annual Maturities of Long-Term Debt (Table)	'
	At December 31, 2013, future annual maturities of the long-term debt were as follows (in millions):
	Year ending December 31:
	2014	$	0.3
	2015		5.3
	2016		—
	2017		299.8
	2018		—
	Thereafter		2,296.00
	Total future maturities of the long-term debt	$	2,601.40

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Taxes	'
Income Tax Expense (Benefit) from Continuing Operations (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Current income taxes (benefits):
	U.S. federal	$	109.5		$	(66.9	)	$	115.4
	State		7.7			(4.7	)		7.2
	Foreign		69.7			48.7			44.4
	Tax benefit of operating loss carryforward		(134.1	)		(73.7	)		(0.2	)
	Total current income taxes (benefits)		52.8			(96.6	)		166.8
	U.S. federal		155.1			221.3			43.9
	State		(3.1	)		(1.7	)		(2.6	)
	Foreign		(16.9	)		11.6			(9.8	)
	Total deferred income taxes		135.1			231.2			31.5
	Total income taxes	$	187.9		$	134.6		$	198.3
Reconciliation Between U.S. Corporate Income Tax Rate and Effective Income Tax Rate from Continuing Operations (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
	U.S. corporate income tax rate		35	%		35	%		35	%
	Dividends received deduction		(10	)		(10	)		(9	)
	Impact of equity method presentation		(3	)		(4	)		(4	)
	Interest exclusion from taxable income		(2	)		(2	)		(3	)
	Foreign tax rate differential		(2	)		(2	)		—
	Impact of court ruling on some uncertain tax positions		—			—			7
	Other		(1	)		(3	)		(3	)
	Effective income tax rate		17	%		14	%		23	%
Changes in Unrecognized Tax Benefits (Table)	'
		For the year
		ended
		December 31,
		2013			2012
		(in millions)
	Balance at beginning of period	$	119.5		$	114.3
	Additions based on tax positions related to the current year		10.5			10.5
	Additions for tax positions of prior years		10.9			4.4
	Reductions for tax positions related to the current year		(3.3	)		(4.2	)
	Reductions for tax positions of prior years		(28.7	)		(5.5	)
	Balance at end of period (1)	$	108.9		$	119.5
	-1
	Of this amount, $55.4 million, if recognized, would reduce the 2013 effective income tax rate. We recognize interest and penalties related to uncertain tax positions in operating expenses.
Components of Net Deferred Income Taxes (Table)	'
		December 31,
		2013			2012
		(in millions)
	Deferred income tax assets:
	Insurance liabilities	$	241.1		$	544
	Investments, including derivatives		464.2			530.5
	Net operating and capital loss carryforwards		339.8			386.2
	Employee benefits		320.6			491.9
	Other deferred income tax assets		90.4			55.9
	Gross deferred income tax assets		1,456.10			2,008.50
	Valuation allowance		(0.7	)		(2.7	)
	Total deferred income tax assets		1,455.40			2,005.80
	Deferred income tax liabilities:
	Deferred acquisition costs		(807.2	)		(635.3	)
	Investments, including derivatives		(418.3	)		(562.7	)
	Net unrealized gains on available-for-sale securities		(584.5	)		(1,114.9	)
	Real estate		(117.3	)		(102.0	)
	Intangible assets		(297.7	)		(160.0	)
	Other deferred income tax liabilities		(4.8	)		(10.1	)
	Total deferred income tax liabilities		(2,229.8	)		(2,585.0	)
	Total net deferred income tax liabilities	$	(774.4	)	$	(579.2	)
Net Deferred Income Taxes by Jurisdiction (Table)	'
		December 31,
		2013			2012
		(in millions)
	Deferred income tax assets:
	State	$	—		$	3.9
	Foreign		49.6			16.9
	Net deferred income tax assets		49.6			20.8
	Deferred income tax liabilities:
	U.S. Federal		(503.4	)		(446.2	)
	State		(1.5	)		—
	Foreign		(319.1	)		(153.8	)
	Net deferred income tax liabilities		(824.0	)		(600.0	)
	Total net deferred income tax liabilities	$	(774.4	)	$	(579.2	)

Employee_and_Agent_Benefits_Ta

Employee and Agent Benefits (Tables)	12 Months Ended
	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans	'
Obligations and Funded Status (Table)	'
		Pension benefits						Other
								postretirement
								benefits
		December 31,						December 31,
		2013			2012			2013			2012
		(in millions)
	Change in benefit obligation
	Benefit obligation at beginning of year	$	(2,638.0	)	$	(2,158.4	)	$	(147.8	)	$	(165.1	)
	Service cost		(57.1	)		(47.0	)		(1.0	)		(1.3	)
	Interest cost		(103.8	)		(109.1	)		(5.7	)		(8.2	)
	Actuarial gain (loss)		279.2			(407.1	)		7.9			21.2
	Participant contribution		—			—			(6.8	)		(6.6	)
	Benefits paid		79.5			76.4			13.6			13
	Other		—			7.2			(0.8	)		(0.8	)
	Benefit obligation at end of year	$	(2,440.2	)	$	(2,638.0	)	$	(140.6	)	$	(147.8	)
	Change in plan assets
	Fair value of plan assets at beginning of year	$	1,682.10		$	1,429.00		$	519.7		$	466.6
	Actual return on plan assets		199.8			222.6			95.9			58.6
	Employer contribution		123.2			106.9			4.2			0.9
	Participant contributions		—			—			6.8			6.6
	Benefits paid		(79.5	)		(76.4	)		(13.6	)		(13.0	)
	Fair value of plan assets at end of year	$	1,925.60		$	1,682.10		$	613		$	519.7
	Amount recognized in statement of financial position
	Other assets	$	—		$	—		$	473		$	372.5
	Other liabilities		(514.6	)		(955.9	)		(0.6	)		(0.6	)
	Total	$	(514.6	)	$	(955.9	)	$	472.4		$	371.9
	Amount recognized in accumulated other comprehensive (income) loss
	Total net actuarial (gain) loss	$	391.1		$	861.2		$	(83.1	)	$	(7.1	)
	Prior service benefit		(11.8	)		(20.4	)		(56.2	)		(82.1	)
	Pre-tax accumulated other comprehensive (income) loss	$	379.3		$	840.8		$	(139.3	)	$	(89.2	)
Components of Net Periodic Benefit Cost (Income) (Table)	'
		Pension benefits									Other postretirement
											benefits
		For the year ended December 31,
		2013			2012			2011			2013			2012			2011
		(in millions)
	Service cost	$	57.1		$	47		$	44		$	1		$	1.3		$	1.2
	Interest cost		103.8			109.1			108.5			5.7			8.2			8.9
	Expected return on plan assets		(127.4	)		(114.6	)		(114.4	)		(28.8	)		(33.5	)		(34.1	)
	Amortization of prior service benefit		(8.7	)		(9.4	)		(9.7	)		(25.9	)		(28.6	)		(29.3	)
	Recognized net actuarial loss		118.5			90.9			65.8			1			0.9			0.4
	Amounts recognized due to special events		—			(0.7	)		(1.4	)		—			(3.5	)		(5.1	)
	Net periodic benefit cost (income)	$	143.3		$	122.3		$	92.8		$	(47.0	)	$	(55.2	)	$	(58.0	)
Amounts Recognized in Net Periodic Benefit Cost and Accumulated Other Comprehensive (Income) Loss (Table)	'
		Pension						Other
		benefits						postretirement
								benefits
		For the year ended December 31,
		2013			2012			2013			2012
		(in millions)
	Other changes recognized in accumulated other comprehensive (income) loss
	Net actuarial (gain) loss	$	(351.7	)	$	292.1		$	(75.0	)	$	(46.4	)
	Amortization of net loss		(118.5	)		(90.9	)		(1.0	)		(0.9	)
	Amortization of prior service benefit		8.7			10.1			25.9			32.1
	Total recognized in pre-tax accumulated other comprehensive (income) loss	$	(461.5	)	$	211.3		$	(50.1	)	$	(15.2	)
	Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	$	(318.2	)	$	333.6		$	(97.1	)	$	(70.4	)
Weighted-Average Assumptions Used to Determine Benefit Obligations (Table)	'
		Pension						Other
		benefits						postretirement
								benefits
		For the year ended December 31,
		2013			2012			2013			2012
	Discount rate		4.9	%		4	%		4.9	%		4	%
	Rate of compensation increase		4.8	%		4.8	%		4.83	%		4.83	%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Table)	'
		Pension benefits									Other
											postretirement
											benefits
		For the year ended December 31,
		2013			2012			2011			2013			2012			2011
	Discount rate		4	%		5.15	%		5.65	%		4	%		5.15	%		5.65	%
	Expected long-term return on plan assets		7.5	%		8	%		8	%		5.62	%		7.3	%		7.3	%
	Rate of compensation increase		4.8	%		5	%		5	%		4.83	%		5	%		5	%
Assumed Health Care Cost Trend Rates (Table)	'
		December 31,
		2013			2012
	Health care cost trend rate assumed for next year under age 65		8	%		8	%
	Health care cost trend rate assumed for next year age 65 and over		6	%		7	%
	Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		4.5	%		4.5	%
	Year that the rate reaches the ultimate trend rate (under age 65)		2020			2019
	Year that the rate reaches the ultimate trend rate (65 and older)		2019			2017
Effects of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Table)	'
		1-percentage			1-percentage
		point increase			point decrease
		(in millions)
	Effect on total of service cost and interest cost components	$	0.3		$	(0.3	)
	Effect on accumulated postretirement benefit obligation		(6.1	)		5.3
Estimated Future Benefit Payments (Table)	'
		Pension benefits			Other postretirement			Amount of Medicare
					benefits (gross benefit			Part D subsidy receipts
					payments, including
					prescription drug benefits)
		(in millions)
	Year ending December 31:
	2014	$	98.7		$	18.1		$	1
	2015		102.9			18.6			1
	2016		108.2			19			1
	2017		114.4			19.3			1.1
	2018		120.6			19.4			1.1
	2019 - 2023		708.4			99.1			5.1
Defined Benefit Pension Plans Supplemental Information (Table)	'
		For the year ended December 31,
		2013									2012
		Qualified			Nonqualified			Total			Qualified			Nonqualified			Total
		Plan			Plan						Plan			Plan
		(in millions)
	Amount recognized in statement of financial position
	Other assets	$	—		$	—		$	—		$	—		$	—		$	—
	Other liabilities		(138.6	)		(376.0	)		(514.6	)		(557.7	)		(398.2	)		(955.9	)
	Total	$	(138.6	)	$	(376.0	)	$	(514.6	)	$	(557.7	)	$	(398.2	)	$	(955.9	)
	Amount recognized in accumulated other comprehensive loss
	Total net actuarial loss	$	298.3		$	92.8		$	391.1		$	725		$	136.2		$	861.2
	Prior service benefit		(6.5	)		(5.3	)		(11.8	)		(12.5	)		(7.9	)		(20.4	)
	Pre-tax accumulated other comprehensive loss	$	291.8		$	87.5		$	379.3		$	712.5		$	128.3		$	840.8
	Components of net periodic benefit cost
	Service cost	$	50.4		$	6.7		$	57.1		$	42.3		$	4.7		$	47
	Interest cost		88.2			15.6			103.8			92.8			16.3			109.1
	Expected return on plan assets		(127.4	)		—			(127.4	)		(114.6	)		—			(114.6	)
	Amortization of prior service benefit		(6.1	)		(2.6	)		(8.7	)		(6.3	)		(3.1	)		(9.4	)
	Recognized net actuarial loss		104.4			14.1			118.5			84.8			6.1			90.9
	Amounts recognized due to special events		—			—			—			(0.4	)		(0.3	)		(0.7	)
	Net periodic benefit cost	$	109.5		$	33.8		$	143.3		$	98.6		$	23.7		$	122.3
	Other changes recognized in accumulated other comprehensive (income) loss
	Net actuarial (gain) loss	$	(322.4	)	$	(29.3	)	$	(351.7	)	$	223.5		$	68.6		$	292.1
	Amortization of net loss		(104.4	)		(14.1	)		(118.5	)		(84.8	)		(6.1	)		(90.9	)
	Amortization of prior service benefit		6.1			2.6			8.7			6.7			3.4			10.1
	Total recognized in pre-tax accumulated other comprehensive (income) loss	$	(420.7	)	$	(40.8	)	$	(461.5	)	$	145.4		$	65.9		$	211.3
	Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	$	(311.2	)	$	(7.0	)	$	(318.2	)	$	244		$	89.6		$	333.6
Pension benefits	'
Defined Benefit Plans and Other Postretirement Benefit Plans	'
Accumulated Benefit Obligation in Excess of Plan Assets (Table)	'
		December 31,
		2013			2012
		(in millions)
	Projected benefit obligation	$	2,440.20		$	2,638.00
	Accumulated benefit obligation		2,287.40			2,469.10
	Fair value of plan assets		1,925.60			1,682.10
Fair Value of Plan Assets (Table)	'
		As of December 31, 2013
					Fair value hierarchy level
		Assets
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Asset category
	U.S. large cap equity portfolios (1)	$	414		$	—		$	414		$	—
	U.S. small/mid cap equity portfolios (2)		102.9			—			102.9			—
	Balanced asset portfolios (3)		96.9			—			96.9			—
	International equity portfolios (4)		171			—			171			—
	Fixed income security portfolios (5)		1,048.50			—			1,048.50			—
	Real estate investment portfolios:
	Direct real estate investments (6)		92.3			—			92.3			—
	Total	$	1,925.60		$	—		$	1,925.60		$	—
		As of December 31, 2012
					Fair value hierarchy level
		Assets
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Asset category
	U.S. large cap equity portfolios (1)	$	601.8		$	—		$	601.8		$	—
	U.S. small/mid cap equity portfolios (2)		156.2			—			156.2			—
	Balanced asset portfolios (3)		82.4			—			82.4			—
	International equity portfolios (4)		273.9			—			273.9			—
	Fixed income security portfolios (5)		486.6			—			486.6			—
	Real estate investment portfolios:
	Direct real estate investments (6)		81.2			—			81.2			—
	Total	$	1,682.10		$	—		$	1,682.10		$	—
	-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 portfolios invest in various fixed income securities, primarily of U.S. origin. These include, but are not limited to, corporate bonds, mortgage-backed securities, commercial mortgage-backed securities, U.S. Treasury securities, agency securities, asset-backed securities and collateralized mortgage obligations.
	-6
	The portfolio invests primarily in U.S. commercial real estate properties.
Reconciliation of Plan Assets Measured at Fair Value Using Significant Unobservable Inputs (Table)	'
		For the year ended December 31, 2011
					Actual return gains (losses) on plan assets
																				Ending
																				asset
																				balance
																				as of
																				December 31,
		Beginning			Relating to			Relating to			Net			Transfers			Transfers			2011
		asset			assets still			assets sold			purchases,			into			out of
		balance as			held at the			during the			sales and			Level 3			Level 3
		of December 31,			reporting			period			settlements
		2010			date
		(in millions)
	Asset category
	Direct real estate investments	$	84.7		$	1.6		$	—		$	1		$	—		$	(87.3	)	$	—
Target Asset Allocation (Table)	'
	Asset Category	Target allocation
	U.S. equity portfolios	0% - 45%
	International equity portfolios	0% - 15%
	Fixed income security portfolios	30% - 100%
	Real estate investment portfolios	0% - 10%
Other postretirement benefits	'
Defined Benefit Plans and Other Postretirement Benefit Plans	'
Accumulated Benefit Obligation in Excess of Plan Assets (Table)	'
		December 31,
		2013			2012
		(in millions)
	Accumulated postretirement benefit obligation	$	1.5		$	1.7
	Fair value of plan assets		0.9			1.1
Fair Value of Plan Assets (Table)	'
		As of December 31, 2013
					Fair value hierarchy level
		Assets
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Asset category
	Cash and cash equivalents	$	4.7		$	4.7		$	—		$	—
	Fixed income security portfolios:
	Fixed income investment funds (1)		157.9			157.9			—			—
	Principal Life general account investment (2)		38.8			—			—			38.8
	U.S. equity portfolios (3)		351.6			288			63.6			—
	International equity portfolios (4)		60			45.9			14.1			—
	Total	$	613		$	496.5		$	77.7		$	38.8
		As of December 31, 2012
					Fair value hierarchy level
		Assets
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Asset category
	Cash and cash equivalents	$	1.9		$	1.9		$	—		$	—
	Fixed income security portfolios:
	Fixed income investment funds (1)		163.5			163.5			—			—
	Principal Life general account investment (2)		42.1			—			—			42.1
	U.S. equity portfolios (3)		260.8			213.5			47.3			—
	International equity portfolios (4)		51.4			39.3			12.1			—
	Total	$	519.7		$	418.2		$	59.4		$	42.1
	-1
	The portfolios invest in various fixed income securities, primarily of U.S. origin. These include, but are not limited to, corporate bonds, mortgage-backed securities, commercial mortgage-backed securities, U.S. Treasury securities, agency securities, asset-backed securities and collateralized mortgage obligations.
	-2
	The general account is invested in various fixed income securities.
	-3
	The portfolios invest primarily in publicly traded equity securities of large U.S. companies.
	-4
	The portfolios invest primarily in publicly traded equity securities of non-U.S. companies.
Reconciliation of Plan Assets Measured at Fair Value Using Significant Unobservable Inputs (Table)	'
		For the year ended December 31, 2013
					Actual return gains
					(losses) on plan assets															Ending
																				asset
																				balance
																				as of
																				December 31,
		Beginning			Relating to			Relating to			Net			Transfers			Transfers			2013
		asset			assets still			assets sold			purchases,			into			out of
		balance as			held at the			during the			sales, and			Level 3			Level 3
		of December 31,			reporting			period			settlements
		2012			date
		(in millions)
	Asset category
	Principal Life general account investment	$	42.1		$	1.1		$	—		$	(4.4	)	$	—		$	—		$	38.8
		For the year ended December 31, 2012
					Actual return gains (losses) on plan assets
																				Ending
																				assets
																				balance
																				as of
		Beginning									Net									December 31,
		assets									purchases,									2012
		balance as									sales,
		of December 31,									and
		2011			Relating to			Relating to			settlements			Transfers			Transfers
					assets still			assets sold						into			out of
					held at the			during the						Level 3			Level 3
					reporting date			period
		(in millions)
	Asset category
	Principal Life general account investment	$	42.5		$	3.1		$	—		$	(3.5	)	$	—		$	—		$	42.1
		For the year ended December 31, 2011
					Actual return gains
					(losses) on plan assets															Ending
																				assets
																				balance
																				as of
		Beginning																		December 31,
		assets																		2011
		balance as
		of December 31,
		2010			Relating to			Relating to			Net			Transfers			Transfers
					assets still			assets sold			purchases,			into			out of
					held at the			during the			sales, and			Level 3			Level 3
					reporting date			period			settlements
		(in millions)
	Asset category
	Principal Life general account investment	$	44.5		$	3		$	—		$	(5.0	)	$	—		$	—		$	42.5
Target Asset Allocation (Table)	'
	Asset Category	Target allocation
	U.S. equity portfolios	45% - 65%
	International equity portfolios	5% - 15%
	Fixed income security portfolios	30% - 50%

Contingencies_Guarantees_and_I1

Contingencies, Guarantees and Indemnifications (Tables)	12 Months Ended
	Dec. 31, 2013
Contingencies, Guarantees and Indemnifications	'
Operating Lease Obligations (Table)	'
	The following represents payments due by period for operating lease obligations (in millions):
	Year ending December 31:
	2014	$	42.3
	2015		37
	2016		30.9
	2017		23.2
	2018		10.8
	2019 and thereafter		53.9
	Total operating lease obligations		198.1
	Less: Future sublease rental income on noncancelable leases		7.7
	Total future minimum lease payments	$	190.4
Capital Leases Future Minimum Lease Payments (Table)	'
	The following represents future minimum lease payments due by period for capital lease obligations (in millions).
	Year ending December 31:
	2014	$	7.2
	2015		6.1
	2016		4.5
	2017		1.7
	2018		0.1
	Total		19.6
	Less: Amounts representing interest		0.6
	Net present value of minimum lease payments	$	19

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity	'
Schedule of Dividend Payments (Table)	'
	Date of dividend payment	Date of record		Dividend per			Common stock
				common share			dividend
							(in millions)
	2013:00:00
	December 27, 2013	December 9, 2013		$	0.26		$	76.7
	September 27, 2013	September 5, 2013			0.26			76.5
	June 28, 2013	June 3, 2013			0.23			67.6
	March 29, 2013	March 11, 2013			0.23			67.6
	2012:00:00
	December 28, 2012	December 10, 2012		$	0.21		$	61.7
	September 28, 2012	September 6, 2012			0.21			61.6
	June 29, 2012	June 11, 2012			0.18			53.7
	March 30, 2012	March 12, 2012			0.18			54.3
	2011:00:00
	December 2, 2011	November 10, 2011		$	0.7		$	213.7
Reconciliation of Outstanding Shares (Table)	'
		Series A			Series B			Common
		preferred stock			preferred stock			stock
		(in millions)
	Outstanding shares at January 1, 2011		3			10			320.4
	Shares issued		—			—			1.8
	Treasury stock acquired		—			—			(21.1	)
	Outstanding shares at December 31, 2011		3			10			301.1
	Shares issued		—			—			3.2
	Treasury stock acquired		—			—			(10.5	)
	Outstanding shares at December 31, 2012		3			10			293.8
	Shares issued		—			—			5.8
	Treasury stock acquired		—			—			(4.4	)
	Outstanding shares at December 31, 2013		3			10			295.2
Other Comprehensive Income (Loss) (Table)	'
		For the year ended
		December 31, 2013
		Pre-Tax			Tax			After-Tax
		(in millions)
	Net unrealized losses on available-for-sale securities during the period	$	(1,686.5	)	$	559.5		$	(1,127.0	)
	Reclassification adjustment for losses included in net income (1)		61.1			(20.9	)		40.2
	Adjustments for assumed changes in amortization patterns		252.8			(88.5	)		164.3
	Adjustments for assumed changes in policyholder liabilities		575.7			(193.4	)		382.3
	Net unrealized losses on available-for-sale securities		(796.9	)		256.7			(540.2	)
	Noncredit component of impairment losses on fixed maturities, available-for-sale during the period		24.5			(8.3	)		16.2
	Adjustments for assumed changes in amortization patterns		(14.4	)		5.1			(9.3	)
	Noncredit component of impairment losses on fixed maturities, available-for-sale (2)		10.1			(3.2	)		6.9
	Net unrealized losses on derivative instruments during the period		(46.3	)		16.8			(29.5	)
	Reclassification adjustment for losses included in net income (3)		11.6			(4.3	)		7.3
	Adjustments for assumed changes in amortization patterns		10.9			(3.8	)		7.1
	Adjustments for assumed changes in policyholder liabilities		20.5			(7.2	)		13.3
	Net unrealized losses on derivative instruments		(3.3	)		1.5			(1.8	)
	Foreign currency translation adjustment		(282.6	)		13.2			(269.4	)
	Unrecognized postretirement benefit obligation during the period		426.7			(149.3	)		277.4
	Amortization of prior service cost and actuarial loss included in net periodic benefit cost (4)		84.9			(29.7	)		55.2
	Net unrecognized postretirement benefit obligation		511.6			(179.0	)		332.6
	Other comprehensive loss	$	(561.1	)	$	89.2		$	(471.9	)
		For the year ended
		December 31, 2012
		Pre-Tax			Tax			After-Tax
		(in millions)
	Net unrealized gains on available-for-sale securities during the period	$	1,577.30		$	(520.6	)	$	1,056.70
	Reclassification adjustment for losses included in net income (1)		107.8			(38.4	)		69.4
	Adjustments for assumed changes in amortization patterns		(169.0	)		59.1			(109.9	)
	Adjustments for assumed changes in policyholder liabilities		(689.2	)		230.6			(458.6	)
	Net unrealized gains on available-for-sale securities		826.9			(269.3	)		557.6
	Noncredit component of impairment losses on fixed maturities, available-for-sale during the period		(17.3	)		6.1			(11.2	)
	Adjustments for assumed changes in amortization patterns		4			(1.6	)		2.4
	Adjustments for assumed changes in policyholder liabilities		3.2			(1.1	)		2.1
	Noncredit component of impairment losses on fixed maturities, available-for-sale (2)		(10.1	)		3.4			(6.7	)
	Net unrealized losses on derivative instruments during the period		(25.9	)		9.1			(16.8	)
	Reclassification adjustment for losses included in net income (3)		3.4			(1.5	)		1.9
	Adjustments for assumed changes in amortization patterns		25.9			(9.1	)		16.8
	Adjustments for assumed changes in policyholder liabilities		(70.0	)		24.5			(45.5	)
	Net unrealized losses on derivative instruments		(66.6	)		23			(43.6	)
	Foreign currency translation adjustment		(25.4	)		15.6			(9.8	)
	Unrecognized postretirement benefit obligation during the period		(245.7	)		86			(159.7	)
	Amortization of prior service cost and actuarial loss included in net periodic benefit cost (4)		49.6			(17.3	)		32.3
	Net unrecognized postretirement benefit obligation		(196.1	)		68.7			(127.4	)
	Other comprehensive income	$	528.7		$	(158.6	)	$	370.1
		For the year ended
		December 31, 2011
		Pre-Tax			Tax			After-Tax
		(in millions)
	Net unrealized gains on available-for-sale securities during the period	$	559.4		$	(207.9	)	$	351.5
	Reclassification adjustment for losses included in net income (1)		112			(42.9	)		69.1
	Adjustments for assumed changes in amortization patterns		(114.9	)		40.2			(74.7	)
	Adjustments for assumed changes in policyholder liabilities		(230.3	)		93			(137.3	)
	Net unrealized gains on available-for-sale securities		326.2			(117.6	)		208.6
	Noncredit component of impairment losses on fixed maturities, available-for-sale during the period		49.9			(18.0	)		31.9
	Adjustments for assumed changes in amortization patterns		(1.4	)		0.5			(0.9	)
	Noncredit component of impairment losses on fixed maturities, available-for-sale (2)		48.5			(17.5	)		31
	Net unrealized gains on derivative instruments during the period		39.6			(13.8	)		25.8
	Reclassification adjustment for losses included in net income (3)		20.7			(7.4	)		13.3
	Adjustments for assumed changes in amortization patterns		(23.9	)		8.4			(15.5	)
	Net unrealized gains on derivative instruments		36.4			(12.8	)		23.6
	Foreign currency translation adjustment		(130.8	)		(0.1	)		(130.9	)
	Unrecognized postretirement benefit obligation during the period		(286.7	)		100.3			(186.4	)
Amortization of prior service cost and actuarial loss included in net periodic benefit cost (4)		20.7			(7.2	)		13.5
Net unrecognized postretirement benefit obligation		(266.0	)		93.1			(172.9	)
Other comprehensive loss	$	14.3		$	(54.9	)	$	(40.6	)
-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
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 6, Derivative Financial Instruments — Cash Flow Hedges, for further details.
-4
Pre-tax amortization of prior service cost and actuarial loss included in net periodic benefit cost, which is comprised of amortization of prior service cost (benefit) and recognized net actuarial (gain) loss, is reported in operating expenses on the consolidated statements of operations. See Note 12, Employee and Agent Benefits — Components of Net Periodic Benefit Cost, for further details.
Accumulated Other Comprehensive Income (Loss) (Table)	'
		Net unrealized			Noncredit			Net unrealized			Foreign			Unrecognized			Accumulated
		gains on			component of			gains (losses) on			currency			postretirement			other
		available-for-sale			impairment losses			derivative			translation			benefit			comprehensive
		securities			on fixed maturities			instruments			adjustment			obligation			income
					available-for-sale
		(in millions)
	Balances at January 1, 2011	$	652.1		$	(198.2	)	$	11.3		$	34.5		$	(188.2	)	$	311.5
	Other comprehensive income during the period, net of adjustments		139.5			—			10.3			(130.4	)		(186.4	)		(167.0	)
	Amounts reclassified from AOCI		69.1			31			13.3			—			13.5			126.9
	Other comprehensive loss		208.6			31			23.6			(130.4	)		(172.9	)		(40.1	)
	Balances at December 31, 2011		860.7			(167.2	)		34.9			(95.9	)		(361.1	)		271.4
	Other comprehensive income during the period, net of adjustments		488.2			(6.7	)		(45.5	)		(11.0	)		(159.7	)		265.3
	Amounts reclassified from AOCI		69.4			—			1.9			—			32.3			103.6
	Other comprehensive income		557.6			(6.7	)		(43.6	)		(11.0	)		(127.4	)		368.9
	Balances at December 31, 2012		1,418.30			(173.9	)		(8.7	)		(106.9	)		(488.5	)		640.3
	Other comprehensive income during the period, net of adjustments		(580.4	)		—			(9.1	)		(254.6	)		277.4			(566.7	)
	Amounts reclassified from AOCI		40.2			6.9			7.3			—			55.2			109.6
	Other comprehensive loss		(540.2	)		6.9			(1.8	)		(254.6	)		332.6			(457.1	)
	Balances at December 31, 2013	$	878.1		$	(167.0	)	$	(10.5	)	$	(361.5	)	$	(155.9	)	$	183.2
Redeemable Noncontrolling Interest (Table)	'
	Following is a reconciliation of the changes in the redeemable noncontrolling interest (in millions):
	Balance at January 1, 2011	$	—
	Net income attributable to redeemable noncontrolling interest		0.2
	Redeemable noncontrolling interest assumed related to acquisition		22
	Balance at December 31, 2011		22.2
	Net income attributable to redeemable noncontrolling interest		1.9
	Redeemable noncontrolling interest assumed related to acquisition		37.2
	Distributions to redeemable noncontrolling interest		(2.0	)
	Foreign currency translation adjustment		1.1
	Balance at December 31, 2012		60.4
	Net income attributable to redeemable noncontrolling interest		13.6
	Reclassification from stockholders' equity (1)		173.9
	Contributions from redeemable noncontrolling interest		1.2
	Distributions to redeemable noncontrolling interest		(13.9	)
	Purchase of subsidiary shares from redeemable noncontrolling interest		(2.4	)
	Change in redemption value of redeemable noncontrolling interest		19.2
	Foreign currency translation adjustment		(4.8	)
	Balance at December 31, 2013	$	247.2
	-1
	During the third quarter of 2013, we identified a classification error of certain of our noncontrolling interests. The classification error had no impact on net income, but did impact earnings per share to the extent the redemption value of the redeemable noncontrolling interest exceeds the fair value. We evaluated the classification error and related earnings per share impact based on qualitative and quantitative factors in accordance with SEC Staff Accounting Bulletins 99 and 108 and concluded the impact was not material in the current or any prior quarterly or annual periods presented. During the third quarter of 2013, we recorded a $173.9 million increase to redeemable noncontrolling interest and a corresponding decrease to stockholders' equity. See related discussion in Note 19, Earnings Per Share.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Measurements	'
Fair Value (Table)	'
		As of December 31, 2013
		Assets/			Fair value hierarchy level
		(liabilities)
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	780.5		$	409.3		$	371.2		$	—
	Non-U.S. governments		996.8			—			949.3			47.5
	States and political subdivisions		3,658.00			—			3,656.20			1.8
	Corporate		31,919.00			40.3			31,714.70			164
	Residential mortgage-backed securities		2,845.20			—			2,845.20			—
	Commercial mortgage-backed securities		4,026.40			—			4,024.80			1.6
	Collateralized debt obligations		363.4			—			325.6			37.8
	Other debt obligations		4,167.80			—			4,083.70			84.1
	Total fixed maturities, available-for-sale		48,757.10			449.6			47,970.70			336.8
	Fixed maturities, trading		563.1			—			393.2			169.9
	Equity securities, available-for-sale		110.5			38.1			55.5			16.9
	Equity securities, trading		716.9			105.1			611.8			—
	Derivative assets (1)		665.1			—			590.9			74.2
	Other investments (2)		361.1			6.8			211.4			142.9
	Cash equivalents (3)		1,459.00			—			1,459.00			—
	Sub-total excluding separate account assets		52,632.80			599.6			51,292.50			740.7
	Separate account assets		130,018.40			67,215.10			57,538.10			5,265.20
	Total assets	$	182,651.20		$	67,814.70		$	108,830.60		$	6,005.90
	Liabilities
	Investment-type insurance contracts (4)	$	(6.9	)	$	—		$	—		$	(6.9	)
	Derivative liabilities (1)		(1,024.6	)		—			(985.0	)		(39.6	)
	Other liabilities (4)		(322.1	)		—			(248.2	)		(73.9	)
	Total liabilities	$	(1,353.6	)	$	—		$	(1,233.2	)	$	(120.4	)
	Net assets (liabilities)	$	181,297.60		$	67,814.70		$	107,597.40		$	5,885.50
		As of December 31, 2012
		Assets/			Fair value hierarchy level
		(liabilities)
		measured at
		fair value			Level 1			Level 2			Level 3
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	U.S. government and agencies	$	944.3		$	203.5		$	740.8		$	—
	Non-U.S. governments		1,208.30			—			1,164.00			44.3
	States and political subdivisions		3,178.80			—			3,176.90			1.9
	Corporate		34,325.40			85.9			34,065.00			174.5
	Residential mortgage-backed securities		3,226.70			—			3,226.70			—
	Commercial mortgage-backed securities		3,897.40			—			3,897.40			—
	Collateralized debt obligations		379.2			—			301.6			77.6
	Other debt obligations		3,779.20			—			3,764.50			14.7
	Total fixed maturities, available-for-sale		50,939.30			289.4			50,336.90			313
	Fixed maturities, trading		626.7			9.4			450.5			166.8
	Equity securities, available-for-sale		136.5			54.4			66.8			15.3
	Equity securities, trading		252.8			99.8			153			—
	Derivative assets (1)		1,016.70			—			941.6			75.1
	Other investments (2)		272.1			64.1			94.1			113.9
	Cash equivalents (3)		1,772.60			561.4			1,211.20			—
	Sub-total excluding separate account assets		55,016.70			1,078.50			53,254.10			684.1
	Separate account assets		81,653.80			54,010.10			23,027.70			4,616.00
	Total assets	$	136,670.50		$	55,088.60		$	76,281.80		$	5,300.10
	Liabilities
	Investment-type insurance contracts (4)	$	(170.5	)	$	—		$	—		$	(170.5	)
	Derivative liabilities (1)		(1,205.1	)		—			(1,102.5	)		(102.6	)
	Other liabilities (4)		(237.4	)		—			(197.8	)		(39.6	)
	Total liabilities	$	(1,613.0	)	$	—		$	(1,300.3	)	$	(312.7	)
Net assets (liabilities)	$	135,057.50		$	55,088.60		$	74,981.50		$	4,987.40
-1
Within the consolidated statements of financial position, derivative assets are reported with other investments and derivative liabilities are reported with other liabilities. Refer to Note 6, Derivative Financial Instruments, for further information on fair value by class of derivative instruments. Our derivatives are primarily Level 2, with the exception of certain credit default swaps and other swaps that are Level 3.
-2
Primarily includes seed money investments, commercial mortgage loans of consolidated VIEs and equity method investments reported at fair value.
-3
Includes money market instruments and short-term investments with a maturity date of three months or less when purchased.
-4
Includes bifurcated embedded derivatives that are reported at fair value within the same line item in the consolidated statements of financial position in which the host contract is reported. Other liabilities also include obligations of consolidated VIEs reported at fair value.
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, 2013
		Beginning			Total realized/unrealized gains (losses)															Ending			Changes in
		asset/																		asset/			unrealized
		(liability)																		(liability)			gains (losses)
		balance as of																		balance as of			included in
		December 31,																		December 31,			net income
		2012									Net purchases,									2013			relating to positions
											sales,												still held (1)
											issuances
											and
					Included			Included			settlements (4)			Transfers			Transfers
					in net			in other						into			out of
					income (1)			comprehensive						Level 3			Level 3
								income
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	Non-U.S. governments	$	44.3		$	(0.1	)	$	(0.9	)	$	4.2		$	—		$	—		$	47.5		$	(0.1	)
	States and political subdivisions		1.9			—			—			(0.1	)		—			—			1.8			—
	Corporate		174.5			(13.4	)		4.5			(23.0	)		105.3			(83.9	)		164			(10.4	)
	Commercial mortgage-backed securities		—			—			(0.1	)		(0.7	)		2.4			—			1.6			—
	Collateralized debt obligations		77.6			2.1			7.2			(56.0	)		31.7			(24.8	)		37.8			—
	Other debt obligations		14.7			(0.3	)		2.8			34.9			32			—			84.1			(0.3	)
	Total fixed maturities, available-for-sale		313			(11.7	)		13.5			(40.7	)		171.4			(108.7	)		336.8			(10.8	)
	Fixed maturities, trading		166.8			3			—			0.1			—			—			169.9			3.1
	Equity securities, available-for-sale		15.3			(0.2	)		1.8			—			—			—			16.9			(0.2	)
	Derivative assets		75.1			(19.5	)		—			18.6			—			—			74.2			(19.8	)
	Other investments		113.9			11.2			—			17.8			—			—			142.9			11.2
	Separate account assets (2)		4,616.00			574.9			(0.1	)		68.2			12.7			(6.5	)		5,265.20			545.8
	Liabilities
	Investments-type insurance contracts		(170.5	)		147.3			—			16.3			—			—			(6.9	)		145
	Derivative liabilities		(102.6	)		55			(0.1	)		8.1			—			—			(39.6	)		53.9
	Other liabilities (3)		(39.6	)		(34.3	)		—			—			—			—			(73.9	)		(34.3	)
		For the year ended December 31, 2012
																							Changes in
																							unrealized
																							gains (losses)
																							included in
																							net income
		Beginning			Total realized/unrealized gains (losses)															Ending			relating to
		asset/																		asset/			positions
		(liability)																		(liability)			still held (1)
		balance as of																		balance as of
		December 31,									Net purchases,									December 31,
		2011									sales,									2012
											issuances
											and
					Included			Included			settlements (4)			Transfers			Transfers
					in net			in other						into			out of
					income (1)			comprehensive						Level 3			Level 3
								income
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	Non-U.S. governments	$	22.9		$	(0.2	)	$	(0.3	)	$	7.4		$	14.5		$	—		$	44.3		$	(0.1	)
	States and political subdivisions		—			—			0.2			(0.1	)		1.8			—			1.9			—
	Corporate		297			(9.2	)		19.9			(75.5	)		79.7			(137.4	)		174.5			(2.6	)
	Collateralized debt obligations		102.5			(3.3	)		5.1			4.5			—			(31.2	)		77.6			—
	Other debt obligations		27.3			(2.3	)		0.6			(26.2	)		15.3			—			14.7			(2.2	)
	Total fixed maturities, available-for-sale		449.7			(15.0	)		25.5			(89.9	)		111.3			(168.6	)		313			(4.9	)
	Fixed maturities, trading		220.8			3.2			—			(66.7	)		9.5			—			166.8			(4.4	)
	Equity securities, available-for-sale		18			(0.3	)		(2.4	)		—			—			—			15.3			—
	Derivative assets		60.2			2.9			—			12			—			—			75.1			4.9
Other investments		97.5			2.1			—			14.3			—			—			113.9			2.2
Separate account assets (2)		4,198.20			421.3			0.4			(3.6	)		1.6			(1.9	)		4,616.00			412.8
Liabilities
Investments-type insurance contracts		(195.8	)		38.3			(0.1	)		(12.9	)		—			—			(170.5	)		35.3
Derivative liabilities		(177.1	)		39.8			1.3			33.4			—			—			(102.6	)		38.6
Other liabilities (3)		(24.2	)		(23.5	)		—			8.1			—			—			(39.6	)		(20.2	)
	For the year ended December 31, 2011																					Changes in
																						unrealized
																						gains (losses)
																						included
																						in net
																						income
	Beginning			Total realized/unrealized gains (losses)															Ending			relating to
	asset/																		asset/			positions
	(liability)																		(liability)			still held (1)
	balance as of																		balance as of
	December 31,									Net purchases,									December 31,
	2010									sales,									2011
										issuances
										and
				Included			Included			settlements (4)			Transfers			Transfers
				in net			in other						into			out of
				income (1)			comprehensive						Level 3			Level 3
							income
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. governments	$	24.5		$	0.2		$	—		$	(1.8	)	$	—		$	—		$	22.9		$	0.1
Corporate		552.1			(10.8	)		(20.8	)		(42.7	)		103.2			(284.0	)		297			(6.1	)
Commercial mortgage-backed securities		16.2			(3.7	)		5.1			(10.5	)		—			(7.1	)		—			—
Collateralized debt obligations		109.3			(19.6	)		13.8			0.3			—			(1.3	)		102.5			(9.3	)
Other debt obligations		88.8			0.1			(1.1	)		(30.5	)		9			(39.0	)		27.3			—
Total fixed maturities, available-for-sale		790.9			(33.8	)		(3.0	)		(85.2	)		112.2			(331.4	)		449.7			(15.3	)
Fixed maturities, trading		269.1			(16.6	)		—			(27.2	)		20.5			(25.0	)		220.8			(15.8	)
Equity securities, available-for-sale		43.2			(6.1	)		12			(28.0	)		13			(16.1	)		18			(4.5	)
Derivative assets		33.3			37.8			(0.1	)		(10.8	)		—			—			60.2			33.4
Other investments		128.3			(2.5	)		—			(28.3	)		—			—			97.5			(2.6	)
Separate account assets (2)		3,771.50			406.6			—			88.9			13.5			(82.3	)		4,198.20			400.9
Liabilities
Investments-type insurance contracts		(6.6	)		(206.3	)		—			17.1			—			—			(195.8	)		(206.6	)
Derivative liabilities		(181.5	)		(11.4	)		0.2			15.6			—			—			(177.1	)		(8.6	)
Other liabilities (3)		(156.8	)		(1.2	)		13.4			(15.9	)		—			136.3			(24.2	)		(1.1	)
-1
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 fixed maturities, trading and certain derivatives used in relation to certain trading portfolios are reported in net investment income within the consolidated statements of operation.
-2
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.
-3
Certain embedded derivatives reported in other liabilities are part of a cash flow hedge, with the effective portion of the unrealized gains (losses) recorded in AOCI.
-4
Gross purchases, sales, issuances and settlements were:
	For the year ended December 31, 2013
	Purchases			Sales			Issuances			Settlements			Net purchases,
													sales, issuances
													and settlements
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. government	$	9.3		$	(3.9	)	$	—		$	(1.2	)	$	4.2
State and political subdivisions		—			—			—			(0.1	)		(0.1	)
Corporate		32.6			(33.3	)		—			(22.3	)		(23.0	)
Commercial mortgage-backed securities		—			—			—			(0.7	)		(0.7	)
Collateralized debt obligations		17			(47.4	)		—			(25.6	)		(56.0	)
Other debt obligations		37.8			—			—			(2.9	)		34.9
Total fixed maturities, available-for-sale		96.7			(84.6	)		—			(52.8	)		(40.7	)
Fixed maturities, trading		—			—			—			0.1			0.1
Derivative assets		22.1			(3.5	)		—			—			18.6
Other investments		30.2			—			—			(12.4	)		17.8
Separate account assets (5)		418.4			(300.8	)		(21.8	)		(27.6	)		68.2
Liabilities
Investment-type insurance contracts		—			—			11			5.3			16.3
Derivative liabilities		(3.4	)		11.5			—			—			8.1
	For the year ended December 31, 2012
	Purchases			Sales			Issuances			Settlements			Net purchases,
													sales, issuances
													and settlements
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. government	$	13.5		$	(5.0	)	$	—		$	(1.1	)	$	7.4
State and political subdivisions		—			—			—			(0.1	)		(0.1	)
Corporate		29.2			(92.0	)		—			(12.7	)		(75.5	)
Collateralized debt obligations		5.1			(1.1	)		—			0.5			4.5
Other debt obligations		—			—			—			(26.2	)		(26.2	)
Total fixed maturities, available-for-sale		47.8			(98.1	)		—			(39.6	)		(89.9	)
Fixed maturities, trading		—			(24.6	)		—			(42.1	)		(66.7	)
Derivative assets		12.6			(0.6	)		—			—			12
Other investments		34			—			—			(19.7	)		14.3
Separate account assets (5)		342.2			(310.6	)		(208.4	)		173.2			(3.6	)
Liabilities
Investment-type insurance contracts		—			—			(16.6	)		3.7			(12.9	)
Derivative liabilities		(8.9	)		42.3			—			—			33.4
Other liabilities		—			8.1			—			—			8.1
	For the year ended December 31, 2011
	Purchases			Sales			Issuances			Settlements			Net purchases,
													sales, issuances
													and settlements
	(in millions)
Assets
Fixed maturities, available-for-sale:
Non-U.S. government	$	3.6		$	(5.4	)	$	—		$	—		$	(1.8	)
Corporate		21.2			(25.6	)		—			(38.3	)		(42.7	)
Commercial mortgage-backed securities		—			(10.5	)		—			—			(10.5	)
Collateralized debt obligations		1.3			(0.4	)		—			(0.6	)		0.3
Other debt obligations		—			—			—			(30.5	)		(30.5	)
Total fixed maturities, available-for-sale		26.1			(41.9	)		—			(69.4	)		(85.2	)
Fixed maturities, trading		10			(8.7	)		—			(28.5	)		(27.2	)
Equity securities, available-for-sale		0.3			(28.3	)		—			—			(28.0	)
Derivative assets		19			(29.8	)		—			—			(10.8	)
Other investments		—			—			—			(28.3	)		(28.3	)
Separate account assets		342.7			(191.8	)		—			(62.0	)		88.9
Liabilities
Investment-type insurance contracts		—			—			9.2			7.9			17.1
Derivative liabilities		(12.1	)		27.7			—			—			15.6
Other liabilities		(2.1	)		—			—			(13.8	)		(15.9	)
-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, 2013
		Transfers out			Transfers out			Transfers out			Transfers out			Transfers out			Transfers out
		of Level 1 into			of Level 1 into			of Level 2 into			of Level 2 into			of Level 3 into			of Level 3 into
		Level 2			Level 3			Level 1			Level 3			Level 1			Level 2
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	Corporate	$	—		$	—		$	—		$	105.3		$	—		$	83.9
	Commercial mortgage-backed securities		—			—			—			2.4			—			—
	Collateralized debt obligations		—			—			—			31.7			—			24.8
	Other debt obligations		—			—			—			32			—			—
	Total fixed maturities, available-for-sale		—			—			—			171.4			—			108.7
	Separate account assets		253.9			0.1			15.5			12.6			—			6.5
		For the year ended December 31, 2012
		Transfers out			Transfers out			Transfers out			Transfers out			Transfers out			Transfers out
		of Level 1 into			of Level 1 into			of Level 2 into			of Level 2 into			of Level 3 into			of Level 3 into
		Level 2			Level 3			Level 1			Level 3			Level 1			Level 2
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	Non-U.S. governments	$	—		$	—		$	—		$	14.5		$	—		$	—
	States and political subdivisions		—			—			—			1.8			—			—
	Corporate		—			—			—			79.7			—			137.4
	Collateralized debt obligations		—			—			—			—			—			31.2
	Other debt obligations		—			—			—			15.3			—			—
	Total fixed maturities, available-for-sale		—			—			—			111.3			—			168.6
	Fixed maturities, trading		—			—			—			9.5			—			—
	Separate account assets		3,255.70			0.3			205.5			1.3			—			1.9
Quantitative Information about Level 3 Fair Value Measurements (Table)	'
		As of December 31, 2013
		Assets /			Valuation		Unobservable		Input/range of		Weighted
		(liabilities)			technique(s)		input description		inputs		average
		measured at
		fair value
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	Non-U.S. governments	$	11.7		Discounted cash flow		Discount rate (1)		2.00%		2.00%
							Illiquidity premium		50 basis points ("bps")		50bps
	Corporate		70.1		Discounted cash flow		Discount rate (1)		1.9% - 7.7%		4.40%
							Earnings before interest, taxes, depreciation and amortization multiple		0x - 4.5x		0.2x
							Comparability adjustment		0 - 125bps		43bps
							Probability of default		0% - 100%		5.40%
							Potential loss severity		0% - 16%		0.90%
							Illiquidity premium		0bps - 25bps		15bps
	Commercial mortgage-backed securities		1.6		Discounted cash flow		Discount rate (1)		1.5% - 4.5%		0.00%
	Collateralized debt obligations		13.6		Discounted cash flow		Discount rate (1)		1.50%		1.50%
							Illiquidity premium		400bps		400bps
	Other debt obligations		33.6		Discounted cash flow		Discount rate (1)		2.0% - 15.0%		6.70%
							Illiquidity premium		0bps - 50bps		11bps
	Fixed maturities, trading		36.2		Discounted cash flow		Discount rate (1)		1.6% - 83.0%		3.40%
							Illiquidity premium		0bps - 1,400bps		370bps
			110.4		See note (2)
	Other investments		68.1		Discounted cash flow — commercial mortgage loans of consolidated VIEs		Discount rate (1)		4.80%		4.80%
							Illiquidity premium		94bps		94bps
			74.8		Discounted cash flow — equity method real estate investments		Discount rate (1)		7.8% - 8.1%		7.90%
							Terminal capitalization rate		5.5% - 6.8%		6.10%
							Average market rent growth rate		3.5% - 3.6%		3.60%
					Discounted cash flow — equity method real estate investment — debt		Loan to value		40.5% - 61.0%		50.70%
							Credit spread rate		1.5% - 2.0%		1.80%
	Separate account assets		5,090.40		Discounted cash flow — mortgage loans		Discount rate (1)		0.6% - 5.6%		3.30%
							Illiquidity premium		0bps - 60bps		12bps
							Credit spread rate		32bps - 440bps		214bps
					Discounted cash flow — real estate		Discount rate (1)		6.0% - 16.0%		7.60%
							Terminal capitalization rate		4.5% - 9.0%		6.60%
							Average market rent growth rate		2.4% - 4.7%		3.00%
					Discounted cash flow — real estate debt		Loan to value		11.0% - 55.9%		50.30%
							Credit spread rate		1.5% - 5.2%		3.30%
	Liabilities
	Investment-type insurance contracts		(6.9	)	Discounted cash flow		Long duration interest rate		3.8% - 3.9% (3)
							Long-term equity market volatility		15.0% - 40.1%
							Non-performance risk		0.2% - 1.2%
							Utilization rate		See note (4)
							Lapse rate		0.5% - 14.6%
							Mortality rate		See note (5)
	Derivative liabilities		(19.9	)	See note (2)
	Other liabilities		(73.9	)	See note (2)
		As of December 31, 2012
		Assets /			Valuation		Unobservable		Input/range of		Weighted
		(liabilities)			technique(s)		input description		inputs		average
		measured at
		fair value
		(in millions)
	Assets
	Fixed maturities, available-for-sale:
	Non-U.S. governments	$	12.9		Discounted cash flow		Discount rate (1)		1.60%		1.60%
							Illiquidity premium		50 basis points ("bps")		50bps
	Corporate		66.6		Discounted cash flow		Discount rate (1)		1.7% - 29.0%		8.40%
							Illiquidity premium		0bps - 100bps		39bps
							Earnings before interest, taxes, depreciation and amortization multiple		0x - 3.5x		0.2x
							Probability of default		0% - 100%		6.40%
							Potential loss severity		0% - 30%		1.90%
Collateralized debt obligations		38.2		Discounted cash flow		Discount rate (1)		1.0% - 19.8%		13.30%
						Illiquidity premium		400bps - 1,000bps		791bps
Other debt obligations		14.7		Discounted cash flow		Discount rate (1)		6.5% - 20.0%		11.80%
						Illiquidity premium		0bps - 50bps		30bps
Fixed maturities, trading		35.9		Discounted cash flow		Discount rate (1)		1.2% - 60.5%		4.10%
						Illiquidity premium		0bps - 1,400bps		390bps
		110.4		See note (2)
Other investments		80.3		Discounted cash flow — commercial mortgage loans of consolidated VIEs		Discount rate (1)		3.50%		3.50%
						Illiquidity premium		287bps		287bps
		33.6		Discounted cash flow — equity method real estate investment		Discount rate (1)		9.30%		9.30%
						Terminal capitalization rate		5.50%		5.50%
						Average market rent growth rate		3.60%		3.60%
				Discounted cash flow — equity method real estate investment debt		Loan to value		49.40%		49.40%
						Credit spread rate		3.30%		3.30%
Separate account assets		4,449.00		Discounted cash flow — mortgage loans		Discount rate (1)		0.8% - 10.4%		3.30%
						Illiquidity premium		0bps - 50bps		20bps
						Credit spread rate		44bps - 975bps		286bps
				Discounted cash flow — real estate		Discount rate (1)		6.5% - 16.0%		8.30%
						Terminal capitalization rate		4.8% - 9.0%		7.20%
						Average market rent growth rate		2.3% - 5.5%		3.30%
				Discounted cash flow — real estate debt		Loan to value		17.0% - 86.0%		54.80%
						Credit spread rate		1.6% - 5.3%		3.50%
Liabilities
Investment-type insurance contracts		(170.5	)	Discounted cash flow		Long duration interest rate		2.6% - 2.8% (3)
						Long-term equity market volatility		16.1% - 38.3%
						Non-performance risk		0.3% - 1.6%
						Utilization rate		See note (4)
						Lapse rate		0.5% - 14.6%
						Mortality rate		See note (5)
Derivative liabilities		(65.1	)	See note (2)
Other liabilities		(39.6	)	See note (2)
-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 credit spread, illiquidity or other adjustments, where applicable.
-2
Relates to a consolidated collateralized private investment vehicle that is a VIE. Fixed maturities, trading represents the underlying collateral of the investment structure and consists of high-grade fixed maturity investments, which are over-collateralized based on outstanding notes priced at par. The derivative liability represents credit default swaps that are valued using a correlation model to the credit default swap ("CDS") Index ("CDX") and inputs to the valuation are based on observable market data such as the end of period swap curve, CDS constituents of the index and spread levels of the index, as well as CDX tranche spreads. The other liabilities represent obligations to third party note holders due at maturity or termination of the trust. The value of the obligations reflect the third parties' interest in the investment structure.
-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 observable 20 and 30-year 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.
Financial Instruments Not Reported at Fair Value (Table)	'
		December 31, 2013
								Fair value hierarchy level
		Carrying amount
					Fair value			Level 1			Level 2			Level 3
		(in millions)
	Assets (liabilities)
	Mortgage loans	$	11,533.60		$	11,773.50		$	—		$	—		$	11,773.50
	Policy loans		859.7			963.3			—			—			963.3
	Other investments		174			174.7			—			140.9			33.8
	Cash and cash equivalents		912.8			912.8			912.8			—			—
	Investments-type insurance contracts		(29,909.6	)		(30,093.1	)		—			(5,902.2	)		(24,190.9	)
	Short-term debt		(150.6	)		(150.6	)		—			(150.6	)		—
	Long-term debt		(2,601.4	)		(2,692.1	)		—			(2,639.0	)		(53.1	)
	Separate account liabilities		(119,500.7	)		(118,059.7	)		—			—			(118,059.7	)
	Bank deposits		(1,949.0	)		(1,951.1	)		(1,252.2	)		(698.9	)		—
	Cash collateral payable		(32.5	)		(32.5	)		(32.5	)		—			—
		December 31, 2012
								Fair value hierarchy level
		Carrying amount
					Fair value			Level 1			Level 2			Level 3
		(in millions)
	Assets (liabilities)
	Mortgage loans	$	11,519.70		$	12,163.70		$	—		$	—		$	12,163.70
	Policy loans		864.9			1,056.80			—			—			1,056.80
	Other investments		280.1			280.5			—			195.3			85.2
	Cash and cash equivalents		2,404.60			2,404.60			2,364.60			40			—
	Investments-type insurance contracts		(31,953.1	)		(32,531.6	)		—			(7,367.4	)		(25,164.2	)
	Short-term debt		(40.8	)		(40.8	)		—			(40.8	)		—
	Long-term debt		(2,671.3	)		(2,951.4	)		—			(2,921.7	)		(29.7	)
	Separate account liabilities		(73,096.0	)		(72,173.8	)		—			—			(72,173.8	)
	Bank deposits		(2,174.7	)		(2,177.7	)		(1,404.4	)		(773.3	)		—
	Cash collateral payable		(205.6	)		(205.6	)		(205.6	)		—			—

Statutory_Insurance_Financial_1

Statutory Insurance Financial Information (Tables)	12 Months Ended
	Dec. 31, 2013
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,
		2013		2012		2011
		(in millions)
	Statutory net income	$	607.9	$	576.1	$	326.8
	Statutory capital and surplus		4,142.20		3,944.30		4,218.20

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Information	'
Reconciliation of Assets from Segment to Consolidated (Table)	'
		December 31, 2013			December 31, 2012
		(in millions)
	Assets:
	Retirement and Investor Services	$	128,736.70		$	117,399.50
	Principal Global Investors		1,312.10			1,282.20
	Principal International		54,243.60			19,170.90
	U.S. Insurance Solutions		20,033.60			19,017.20
	Corporate		3,865.40			4,960.40
	Total consolidated assets	$	208,191.40		$	161,830.20
Reconciliation of Operating Revenues and Operating Earnings (Losses) by Segment (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Operating revenues by segment:
	Retirement and Investor Services	$	4,847.60		$	4,834.90		$	4,075.00
	Principal Global Investors		719.2			591.2			546.3
	Principal International		1,150.00			942.7			909
	U.S. Insurance Solutions		3,106.40			2,994.70			2,939.90
	Corporate		(215.8	)		(188.1	)		(189.2	)
	Total segment operating revenues		9,607.40			9,175.40			8,281.00
	Net realized capital gains (losses), net of related revenue adjustments		(320.0	)		14.7			(221.5	)
	Exited group medical insurance business		2.1			25			606.3
	Assumption change within our Individual Life business		—			—			4.9
	Total revenues per consolidated statements of operations	$	9,289.50		$	9,215.10		$	8,670.70
	Operating earnings (loss) by segment, net of related income taxes:
	Retirement and Investor Services	$	694.4		$	575.1		$	562.9
	Principal Global Investors		102.6			81.2			74
	Principal International		215.2			154.1			135
	U.S. Insurance Solutions		196.6			138.2			204.3
	Corporate		(148.9	)		(139.8	)		(146.9	)
	Total segment operating earnings, net of related income taxes		1,059.90			808.8			829.3
	Net realized capital gains (losses), as adjusted (1)		(179.1	)		39			(141.7	)
	Other after-tax adjustments (2)		(1.1	)		(74.2	)		(82.3	)
	Net income available to common stockholders per consolidated statements of operations	$	879.7		$	773.6		$	605.3
	-1
	Net realized capital gains (losses), as adjusted, is derived as follows:
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Net realized capital gains (losses):
	Net realized capital gains (losses)	$	(225.2	)	$	114.1		$	(122.3	)
	Certain derivative and hedging-related adjustments		(93.9	)		(98.9	)		(98.8	)
	Certain market value adjustments to fee revenues		—			(0.3	)		(0.1	)
	Recognition of front-end fee revenue		(0.9	)		(0.2	)		(0.3	)
	Net realized capital gains (losses), net of related revenue adjustments		(320.0	)		14.7			(221.5	)
	Amortization of deferred acquisition costs and other actuarial balances		47.1			36.6			(21.5	)
	Capital gains distributed		(25.8	)		(12.2	)		(3.1	)
	Certain market value adjustments of embedded derivatives		18.4			(0.6	)		65.6
	Net realized capital (gains) losses associated with exited group medical insurance business		—			0.2			(0.2	)
	Noncontrolling interest capital gains		(0.2	)		(8.3	)		(31.6	)
	Income tax effect		101.4			8.6			70.6
	Net realized capital gains (losses), as adjusted	$	(179.1	)	$	39		$	(141.7	)
	-2
	For the year ended December 31, 2013, other after-tax adjustments included the negative effect of losses associated with our exited group medical insurance business that does not qualify for discontinued operations accounting treatment under U.S. GAAP.
	For the year ended December 31, 2012, other after-tax adjustments included the negative effect of (a) a contribution made to The Principal Financial Group Foundation, Inc. ($39.8 million), (b) one-time costs incurred to extinguish long-term debt that was scheduled to mature in 2014 ($24.8 million) and (c) losses associated with our exited group medical insurance business that does not qualify for discontinued operations accounting treatment under U.S. GAAP ($9.6 million).
	For the year ended December 31, 2011, other after-tax adjustments included (1) the negative effect resulting from (a) the impact of a court ruling on some uncertain tax positions ($68.9 million), (b) an assumption change in our Individual Life business ($34.5 million), (c) a contribution made to The Principal Financial Group Foundation, Inc. ($19.5 million) and (d) our estimated obligation associated with Executive Life of New York's liquidation petition ($10.3 million) and (2) the positive effect of gains associated with our exited group medical insurance business that does not qualify for discontinued operations accounting treatment under U.S. GAAP ($50.9 million).
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Income tax expense by segment:
	Retirement and Investor Services	$	195.6		$	150		$	163.9
	Principal Global Investors		55.5			43.5			41
	Principal International		28			0.6			(3.1	)
	U.S. Insurance Solutions		94			61.3			95.3
	Corporate		(83.2	)		(69.6	)		(72.9	)
	Total segment income taxes from operating earnings		289.9			185.8			224.2
	Tax benefit related to net realized capital losses, as adjusted		(101.4	)		(8.6	)		(70.6	)
	Tax expense (benefit) related to other after-tax adjustments		(0.6	)		(42.6	)		44.7
	Total income taxes expense per consolidated statements of operations	$	187.9		$	134.6		$	198.3
Reconciliation of Depreciation and Amortization Expense from Segments to Consolidated (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Depreciation and amortization expense by segment:
	Retirement and Investor Services	$	26.7		$	26.3		$	24.7
	Principal Global Investors		11.8			13.3			11.3
	Principal International		47.8			18.9			14.8
	U.S. Insurance Solutions		17.2			17			16.6
	Corporate		4.6			5.4			5
	Total segment depreciation and amortization expense included in operating earnings		108.1			80.9			72.4
	Depreciation and amortization expense related to other after-tax adjustments		1.4			6.1			6.1
	Total depreciation and amortization expense included in our consolidated statements of operations	$	109.5		$	87		$	78.5
Operating Revenue for Products and Services by Segment (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Retirement and Investor Services:
	Full service accumulation	$	1,470.70		$	1,357.00		$	1,338.00
	Principal Funds		765.8			619.6			560.4
	Individual annuities		1,366.50			1,162.40			1,119.20
	Bank and trust services		95.2			101.6			100.5
	Eliminations		(146.8	)		(120.3	)		(111.8	)
	Total Accumulation		3,551.40			3,120.30			3,006.30
	Investment only		341			431.6			508
	Full service payout		955.2			1,283.00			560.7
	Total Guaranteed		1,296.20			1,714.60			1,068.70
	Total Retirement and Investor Services		4,847.60			4,834.90			4,075.00
	Principal Global Investors (1)		719.2			591.2			546.3
	Principal International		1,150.00			942.7			909
	U.S. Insurance Solutions:
	Individual life insurance		1,483.00			1,423.30			1,432.00
	Specialty benefits insurance		1,623.60			1,571.40			1,507.90
	Eliminations		(0.2	)		—			—
	Total U.S. Insurance Solutions		3,106.40			2,994.70			2,939.90
	Corporate		(215.8	)		(188.1	)		(189.2	)
	Total operating revenues	$	9,607.40		$	9,175.40		$	8,281.00
	Total operating revenues	$	9,607.40		$	9,175.40		$	8,281.00
	Net realized capital gains (losses), net of related revenue adjustments		(320.0	)		14.7			(221.5	)
	Exited group medical insurance business		2.1			25			606.3
	Assumption change within our Individual Life business		—			—			4.9
	Total revenues per consolidated statements of operations	$	9,289.50		$	9,215.10		$	8,670.70
	-1
	Reflects inter-segment revenues of $243.7 million, $217.6 million and $212.2 million for the years ended December 31, 2013, 2012 and 2011, respectively.

StockBased_Compensation_Plans_

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Stock-Based Compensation Plans	'
Stock-Based Compensation Disclosures (Table)	'
		For the year ended
		December 31,
		2013			2012			2011
		(in millions)
	Compensation cost	$	65.2		$	53.7		$	46.3
	Related income tax benefit		20			17.7			15.8
	Capitalized as part of an asset		2.6			2.3			2.2
Nonqualified Stock Options Status (Table)	'
		Number of options			Weighted-			Intrinsic value
					average
					exercise price
		(in millions)						(in millions)
	Options outstanding at January 1, 2013		12.2		$	39.61
	Granted		0.8			30.7
	Exercised		3.3			32.03
	Expired		0.1			44.75
	Options outstanding at December 31, 2013		9.6		$	41.37		$	112.2
	Options vested or expected to vest at December 31, 2013		9.6		$	41.39		$	112
	Options exercisable at December 31, 2013		8.1		$	43.47		$	83.3
Nonqualified Stock Options Remaining Contractual Lives and Range of Exercise Prices (Table)	'
	Range of exercise prices	Number of options			Weighted-
		outstanding			average remaining
					contractual life
		(in millions)
	$11.07 - $21.69		1.1			5.2
	$21.70 - $32.32		2.3			8
	$32.33 - $42.95		1.5			3
	$42.96 - $53.58		1.7			2.2
	$53.59 - $64.22		3			3.7
	$11.07 - $64.22		9.6			4.5
Nonqualified Stock Options Fair Value (Table)	'
		For the year ended
		December 31,
	Options	2013			2012			2011
	Expected volatility		53.3	%		70	%		67.9	%
	Expected term (in years)		6.5			6			6
	Risk-free interest rate		1.1	%		1.1	%		2.5	%
	Expected dividend yield		3	%		2.55	%		1.6	%
	Weighted average estimated fair value	$	11.95		$	13.95		$	18.82
Nonvested Performance Share Awards Activity (Table)	'
		Number of			Weighted-
		performance			average grant-date
		share awards			fair value
		(in millions)
	Nonvested performance share awards at January 1, 2013		1		$	27.28
	Granted		0.3			30.7
	Vested		0.3			22.21
	Nonvested performance share awards at December 31, 2013		1		$	30.3
Nonvested Restricted Stock Units Activity (Table)	'
		Number of			Weighted-
		restricted			average grant-date
		stock units			fair value
		(in millions)
	Nonvested restricted stock units at January 1, 2013		3.1		$	27.3
	Granted		1.3			31.02
	Vested		1.2			22.73
	Canceled		0.1			30.37
	Nonvested restricted stock units at December 31, 2013		3.1		$	30.46

Earnings_Per_Common_Share_Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Common Share	'
Earnings Per Common Share (Table)	'
		For the year ended
		December 31,
		2013		2012		2011
		(in millions, except per
		share data)
	Net income	$	936.1	$	825.4	$	674.5
	Subtract:
	Net income attributable to noncontrolling interest		23.4		18.8		36.2
	Preferred stock dividends		33		33		33
	Adjustments to redemption amounts of redeemable noncontrolling interests (1)		—		—		—
	Net income available to common stockholders	$	879.7	$	773.6	$	605.3
	Weighted-average shares outstanding:
	Basic		294.6		297.5		314.5
	Dilutive effects:
	Stock options		1.6		1		1.2
	Restricted stock units		1.7		1.5		1.5
	Performance share awards		0.3		0.4		0.4
	Diluted		298.2		300.4		317.6
	Net income per common share:
	Basic	$	2.99	$	2.6	$	1.92
	Diluted	$	2.95	$	2.58	$	1.91
	-1
	During the third quarter of 2013, we identified a classification error of certain of our noncontrolling interests, which had a related impact to earnings per share. See related discussion in Note 14, Stockholders' Equity — Noncontrolling Interest. The correction of the classification error in the third quarter of 2013 did not significantly impact earnings per share.

Quarterly_Results_of_Operation1

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
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)
	2013
	Total revenues	$	2,672.60	$	2,239.60	$	2,210.60	$	2,166.70
	Total expenses		2,362.70		1,919.30		1,945.00		1,938.50
	Net income		250.4		259.1		236.6		190
	Net income available to common stockholders		233.4		245.7		222.3		178.3
	Basic earnings per common share for net income available to common stockholders		0.79		0.83		0.76		0.61
	Diluted earnings per common share for net income available to common stockholders		0.78		0.82		0.75		0.61
	2012
	Total revenues	$	2,295.90	$	2,704.70	$	2,118.60	$	2,095.90
	Total expenses		2,035.00		2,513.10		1,889.10		1,817.90
	Net income		226.7		198.8		178.6		221.3
	Net income available to common stockholders		214.9		187.2		167.6		203.9
	Basic earnings per common share for net income available to common stockholders		0.72		0.64		0.56		0.68
	Diluted earnings per common share for net income available to common stockholders		0.72		0.63		0.56		0.68

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	12 Months Ended
	Dec. 31, 2013
Condensed Consolidating Financial Information	'
Condensed Consolidating Financial Information, Notes Guarantor (Table)	'
	Condensed Consolidating Statements of Financial Position
	December 31, 2013
		Principal			Principal Life			Principal Financial			Eliminations			Principal
		Financial			Insurance			Services, Inc. and						Financial
		Group, Inc.			Company			Other Subsidiaries						Group, Inc.
		Parent Only			Only			Combined						Consolidated
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	—		$	42,794.70		$	6,357.50		$	(395.1	)	$	48,757.10
	Fixed maturities, trading		—			245.5			317.6			—			563.1
	Equity securities, available-for-sale		—			102.6			7.9			—			110.5
	Equity securities, trading		—			0.3			716.6			—			716.9
	Mortgage loans		—			10,501.50			1,345.90			(313.8	)		11,533.60
	Real estate		—			7.9			1,263.70			—			1,271.60
	Policy loans		—			830.1			29.6			—			859.7
	Investment in unconsolidated entities		11,956.20			3,396.80			4,891.60			(19,364.6	)		880
	Other investments		9.3			1,892.40			1,238.80			(1,076.1	)		2,064.40
	Cash and cash equivalents		131.5			1,332.20			894.5			13.6			2,371.80
	Accrued investment income		—			474.5			59			(1.4	)		532.1
	Premiums due and other receivables		—			1,029.00			1,814.50			(1,602.5	)		1,241.00
	Deferred acquisition costs		—			2,848.80			228.2			—			3,077.00
	Property and equipment		—			422.1			78.6			—			500.7
	Goodwill		—			54.3			1,046.00			—			1,100.30
	Other intangibles		—			26.9			1,432.10			—			1,459.00
	Separate account assets		—			83,790.20			46,228.20			—			130,018.40
	Other assets		59.2			976.9			2,115.30			(2,017.2	)		1,134.20
	Total assets	$	12,156.20		$	150,726.70		$	70,065.60		$	(24,757.1	)	$	208,191.40
	Liabilities
	Contractholder funds	$	—		$	34,918.00		$	1,330.70		$	(290.4	)	$	35,958.30
	Future policy benefits and claims		—			18,292.90			4,625.00			(291.7	)		22,626.20
	Other policyholder funds		—			705.1			54.2			(0.4	)		758.9
	Short-term debt		—			—			150.6			—			150.6
	Long-term debt		2,448.80			99.4			367			(313.8	)		2,601.40
	Income taxes currently payable		—			—			67.4			(62.2	)		5.2
	Deferred income taxes		—			(25.0	)		1,030.10			(181.1	)		824
	Separate account liabilities		—			83,790.20			46,228.20			—			130,018.40
	Other liabilities		23.2			5,204.80			3,911.80			(3,915.6	)		5,224.20
	Total liabilities		2,472.00			142,985.40			57,765.00			(5,055.2	)		198,167.20
	Redeemable noncontrolling interest		—			—			247.2			—			247.2
	Stockholders' equity
	Series A preferred stock		—			—			—			—			—
	Series B preferred stock		0.1			—			—			—			0.1
	Common stock		4.6			2.5			—			(2.5	)		4.6
	Additional paid-in capital		9,798.90			5,505.00			9,163.70			(14,668.7	)		9,798.90
	Retained earnings		5,405.40			1,738.10			2,578.20			(4,316.3	)		5,405.40
	Accumulated other comprehensive income		183.2			495.7			214.3			(710.0	)		183.2
	Treasury stock, at cost		(5,708.0	)		—			—			—			(5,708.0	)
	Total stockholders' equity attributable to PFG		9,684.20			7,741.30			11,956.20			(19,697.5	)		9,684.20
	Noncontrolling interest		—			—			97.2			(4.4	)		92.8
	Total stockholders' equity		9,684.20			7,741.30			12,053.40			(19,701.9	)		9,777.00
	Total liabilities and stockholders' equity	$	12,156.20		$	150,726.70		$	70,065.60		$	(24,757.1	)	$	208,191.40
	Condensed Consolidating Statements of Financial Position
	December 31, 2012
		Principal			Principal Life			Principal Financial			Eliminations			Principal
		Financial			Insurance			Services, Inc. and						Financial
		Group, Inc.			Company			Other Subsidiaries						Group, Inc.
		Parent Only			Only			Combined						Consolidated
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	—		$	44,614.60		$	6,681.70		$	(357.0	)	$	50,939.30
	Fixed maturities, trading		10.5			284.4			331.8			—			626.7
	Equity securities, available-for-sale		—			131.3			5.2			—			136.5
	Equity securities, trading		—			0.3			252.5			—			252.8
Mortgage loans		—			10,054.20			1,775.50			(310.0	)		11,519.70
Real estate		—			8.4			1,171.90			—			1,180.30
Policy loans		—			834			30.9			—			864.9
Investment in unconsolidated entities		11,853.30			3,309.20			4,808.30			(19,101.8	)		869
Other investments		11.1			2,834.00			1,208.40			(1,631.4	)		2,422.10
Cash and cash equivalents		207.1			1,698.40			2,286.90			(15.2	)		4,177.20
Accrued investment income		—			521.6			64.5			(1.7	)		584.4
Premiums due and other receivables		0.1			916.7			1,327.10			(1,159.5	)		1,084.40
Deferred acquisition costs		—			2,394.80			195.2			—			2,590.00
Property and equipment		—			402.2			62			—			464.2
Goodwill		—			54.3			489.1			—			543.4
Other intangibles		—			27.9			886.8			—			914.7
Separate account assets		—			69,217.80			12,436.00			—			81,653.80
Other assets		78			947.8			1,567.70			(1,586.7	)		1,006.80
Total assets	$	12,160.10		$	138,251.90		$	35,581.50		$	(24,163.3	)	$	161,830.20
Liabilities
Contractholder funds	$	—		$	37,053.30		$	1,011.90		$	(278.7	)	$	37,786.50
Future policy benefits and claims		—			17,944.90			4,679.60			(188.3	)		22,436.20
Other policyholder funds		—			676.5			40.3			(0.4	)		716.4
Short-term debt		—			—			40.8			—			40.8
Long-term debt		2,448.60			99.4			433.3			(310.0	)		2,671.30
Income taxes currently payable		—			—			84.7			(69.4	)		15.3
Deferred income taxes		—			324.5			378.4			(102.9	)		600
Separate account liabilities		—			69,217.80			12,436.00			—			81,653.80
Other liabilities		28.1			5,375.10			4,538.40			(3,795.5	)		6,146.10
Total liabilities		2,476.70			130,691.50			23,643.40			(4,745.2	)		152,066.40
Redeemable noncontrolling interest		—			—			60.4			—			60.4
Stockholders' equity
Series A preferred stock		—			—			—			—			—
Series B preferred stock		0.1			—			—			—			0.1
Common stock		4.5			2.5			—			(2.5	)		4.5
Additional paid-in capital		9,730.90			5,747.60			9,393.80			(15,141.4	)		9,730.90
Retained earnings		4,862.00			1,167.70			1,783.40			(2,951.1	)		4,862.00
Accumulated other comprehensive income		640.3			642.6			676.1			(1,318.7	)		640.3
Treasury stock, at cost		(5,554.4	)		—			—			—			(5,554.4	)
Total stockholders' equity attributable to PFG		9,683.40			7,560.40			11,853.30			(19,413.7	)		9,683.40
Noncontrolling interest		—			—			24.4			(4.4	)		20
Total stockholders' equity		9,683.40			7,560.40			11,877.70			(19,418.1	)		9,703.40
Total liabilities and stockholders' equity	$	12,160.10		$	138,251.90		$	35,581.50		$	(24,163.3	)	$	161,830.20
Condensed Consolidating Statements of Operations
For the year ended December 31, 2013
	Principal			Principal Life			Principal Financial			Eliminations			Principal
	Financial			Insurance			Services, Inc. and						Financial
	Group, Inc.			Company			Other Subsidiaries						Group, Inc.
	Parent Only			Only			Combined						Consolidated
	(in millions)
Revenues
Premiums and other considerations	$	—		$	2,788.10		$	366		$	—		$	3,154.10
Fees and other revenues		—			1,723.80			1,855.00			(356.6	)		3,222.20
Net investment income		0.4			2,354.50			753.8			29.7			3,138.40
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		6.3			(779.5	)		663.9			0.1			(109.2	)
Total other-than-temporary impairment losses on available-for-sale securities		—			(85.6	)		(5.9	)		—			(91.5	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income		—			(17.0	)		(7.5	)		—			(24.5	)
Net impairment losses on available-for-sale securities		—			(102.6	)		(13.4	)		—			(116.0	)
Net realized capital gains (losses)		6.3			(882.1	)		650.5			0.1			(225.2	)
Total revenues		6.7			5,984.30			3,625.30			(326.8	)		9,289.50
Expenses
Benefits, claims and settlement expenses		—			4,056.60			639.2			(12.2	)		4,683.60
Dividends to policyholders		—			189			—			—			189
Operating expenses		140.5			1,887.70			1,567.50			(302.8	)		3,292.90
Total expenses		140.5			6,133.30			2,206.70			(315.0	)		8,165.50
Income (loss) before income taxes		(133.8	)		(149.0	)		1,418.60			(11.8	)		1,124.00
Income taxes (benefits)		(54.0	)		(167.5	)		412.6			(3.2	)		187.9
Equity in the net income of subsidiaries		992.5			678.1			10.1			(1,680.7	)		—
Net income		912.7			696.6			1,016.10			(1,689.3	)		936.1
Net income attributable to noncontrolling interest		—			—			23.6			(0.2	)		23.4
Net income attributable to PFG		912.7			696.6			992.5			(1,689.1	)		912.7
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	879.7		$	696.6		$	992.5		$	(1,689.1	)	$	879.7
Net income	$	912.7		$	696.6		$	1,016.10		$	(1,689.3	)	$	936.1
Other comprehensive loss		(450.1	)		(146.6	)		(300.1	)		424.9			(471.9	)
Comprehensive income	$	462.6		$	550		$	716		$	(1,264.4	)	$	464.2
Condensed Consolidating Statements of Operations
For the year ended December 31, 2012
	Principal			Principal Life			Principal Financial			Eliminations			Principal
	Financial			Insurance			Services, Inc. and						Financial
	Group, Inc.			Company			Other Subsidiaries						Group, Inc.
	Parent Only			Only			Combined						Consolidated
	(in millions)
Revenues
Premiums and other considerations	$	—		$	2,878.90		$	340.5		$	—		$	3,219.40
Fees and other revenues		0.5			1,529.70			1,404.10			(307.6	)		2,626.70
Net investment income		3			2,484.50			743.1			24.3			3,254.90
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		0.3			(194.8	)		454.8			(27.6	)		232.7
Total other-than-temporary impairment losses on available-for-sale securities		—			(121.1	)		(14.8	)		—			(135.9	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to other comprehensive income		—			13.8			3.5			—			17.3
Net impairment losses on available-for-sale securities		—			(107.3	)		(11.3	)		—			(118.6	)
Net realized capital gains (losses)		0.3			(302.1	)		443.5			(27.6	)		114.1
Total revenues		3.8			6,591.00			2,931.20			(310.9	)		9,215.10
Expenses
Benefits, claims and settlement expenses		—			4,517.80			618.5			(12.4	)		5,123.90
Dividends to policyholders		—			197.7			—			—			197.7
Operating expenses		170.2			1,764.20			1,265.00			(265.9	)		2,933.50
Total expenses		170.2			6,479.70			1,883.50			(278.3	)		8,255.10
Income (loss) before income taxes		(166.4	)		111.3			1,047.70			(32.6	)		960
Income taxes (benefits)		(67.6	)		(83.2	)		287.1			(1.7	)		134.6
Equity in the net income of subsidiaries		905.4			480.4			163.9			(1,549.7	)		—
Net income		806.6			674.9			924.5			(1,580.6	)		825.4
Net income attributable to noncontrolling interest		—			—			19.1			(0.3	)		18.8
Net income attributable to PFG		806.6			674.9			905.4			(1,580.3	)		806.6
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	773.6		$	674.9		$	905.4		$	(1,580.3	)	$	773.6
Net income	$	806.6		$	674.9		$	924.5		$	(1,580.6	)	$	825.4
Other comprehensive income		321.2			315.2			95.1			(361.4	)		370.1
Comprehensive income	$	1,127.80		$	990.1		$	1,019.60		$	(1,942.0	)	$	1,195.50
Condensed Consolidating Statements of Operations
For the year ended December 31, 2011
	Principal			Principal Life			Principal Financial			Eliminations			Principal
	Financial			Insurance			Services, Inc. and						Financial
	Group, Inc.			Company			Other Subsidiaries						Group, Inc.
	Parent Only			Only			Combined						Consolidated
	(in millions)
Revenues
Premiums and other considerations	$	—		$	2,579.60		$	311.4		$	—		$	2,891.00
Fees and other revenues		0.2			1,566.70			1,257.60			(297.8	)		2,526.70
Net investment income (loss)		(12.0	)		2,578.90			763.2			45.2			3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		—			442.8			(388.7	)		20.9			75
Total other-than-temporary impairment losses on available-for-sale securities		—			(130.6	)		(17.0	)		—			(147.6	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income		—			(51.5	)		1.8			—			(49.7	)
Net impairment losses on available-for-sale securities		—			(182.1	)		(15.2	)		—			(197.3	)
Net realized capital gains (losses)		—			260.7			(403.9	)		20.9			(122.3	)
Total revenues		(11.8	)		6,985.90			1,928.30			(231.7	)		8,670.70
Expenses
Benefits, claims and settlement expenses		—			4,013.00			616.9			(13.3	)		4,616.60
Dividends to policyholders		—			210.2			—			—			210.2
Operating expenses		116			1,965.00			1,142.90			(252.8	)		2,971.10
Total expenses		116			6,188.20			1,759.80			(266.1	)		7,797.90
Income (loss) before income taxes		(127.8	)		797.7			168.5			34.4			872.8
Income taxes (benefits)		(50.4	)		267			(18.5	)		0.2			198.3
Equity in the net income of subsidiaries		715.7			7.2			565.1			(1,288.0	)		—
Net income		638.3			537.9			752.1			(1,253.8	)		674.5
Net income attributable to noncontrolling interest		—			—			36.4			(0.2	)		36.2
Net income attributable to PFG		638.3			537.9			715.7			(1,253.6	)		638.3
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	605.3		$	537.9		$	715.7		$	(1,253.6	)	$	605.3
Net income	$	638.3		$	537.9		$	752.1		$	(1,253.8	)	$	674.5
Other comprehensive income (loss)		(34.5	)		100.1			(166.6	)		60.4			(40.6	)
Comprehensive income	$	603.8		$	638		$	585.5		$	(1,193.4	)	$	633.9
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2013
	Principal			Principal Life			Principal			Eliminations			Principal
	Financial			Insurance			Financial						Financial
	Group, Inc.			Company			Services, Inc. and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(42.8	)	$	2,271.70		$	(170.1	)	$	162.4		$	2,221.20
Investing activities
Available-for-sale securities:
Purchases		—			(7,850.8	)		(1,186.1	)		11.7			(9,025.2	)
Sales		—			1,536.00			434			(50.9	)		1,919.10
Maturities		—			6,433.30			925.9			—			7,359.20
Mortgage loans acquired or originated		—			(2,378.4	)		(202.2	)		387.7			(2,192.9	)
Mortgage loans sold or repaid		—			1,918.00			634.3			(457.2	)		2,095.10
Real estate acquired		—			—			(85.6	)		—			(85.6	)
Net purchases of property and equipment		—			(52.4	)		(7.0	)		—			(59.4	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(1,268.3	)		—			(1,268.3	)
Dividends and returns of capital received from unconsolidated entities		319.5			444.2			319.5			(1,083.2	)		—
Net change in other investments		(3.1	)		56.1			(70.2	)		48.9			31.7
Net cash provided by (used in) investing activities		316.4			106			(505.7	)		(1,143.0	)		(1,226.3	)
Financing activities
Issuance of common stock		125.8			—			—			—			125.8
Acquisition of treasury stock		(153.6	)		—			—			—			(153.6	)
Proceeds from financing element derivatives		—			47			—			—			47
Payments for financing element derivatives		—			(48.0	)		—			—			(48.0	)
Excess tax benefits from share-based payment arrangements		—			3.1			7			—			10.1
Purchase of subsidiary shares from noncontrolling interest		—			—			(52.9	)		—			(52.9	)
Sale of subsidiary shares to noncontrolling interest		—			—			31.8			—			31.8
Dividends to common stockholders		(288.4	)		—			—			—			(288.4	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		—			—			38.2			—			38.2
Principal repayments of long-term debt		—			—			(214.4	)		(3.8	)		(218.2	)
Net proceeds from short-term borrowings		—			—			108			—			108
Dividends and capital paid to parent		—			(249.5	)		(763.7	)		1,013.20			—
Investment contract deposits		—			6,355.10			361.2			—			6,716.30
Investment contract withdrawals		—			(8,846.6	)		(6.1	)		—			(8,852.7	)
Net decrease in banking operation deposits		—			—			(225.7	)		—			(225.7	)
Other		—			(5.0	)		—			—			(5.0	)
Net cash used in financing activities		(349.2	)		(2,743.9	)		(716.6	)		1,009.40			(2,800.3	)
Net decrease in cash and cash equivalents		(75.6	)		(366.2	)		(1,392.4	)		28.8			(1,805.4	)
Cash and cash equivalents at beginning of period		207.1			1,698.40			2,286.90			(15.2	)		4,177.20
Cash and cash equivalents at end of period	$	131.5		$	1,332.20		$	894.5		$	13.6		$	2,371.80
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2012
	Principal			Principal Life			Principal			Eliminations			Principal
	Financial			Insurance			Financial						Financial
	Group, Inc.			Company			Services, Inc. and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	204.8		$	3,133.80		$	(382.5	)	$	124.7		$	3,080.80
Investing activities
Available-for-sale securities:
Purchases		—			(7,254.5	)		(1,024.9	)		15.5			(8,263.9	)
Sales		—			1,183.90			134.8			(15.0	)		1,303.70
Maturities		—			5,805.70			841.8			—			6,647.50
Mortgage loans acquired or originated		—			(2,224.8	)		(250.4	)		(63.2	)		(2,538.4	)
Mortgage loans sold or repaid		—			1,422.20			382.3			(136.5	)		1,668.00
Real estate acquired		—			—			(151.8	)		—			(151.8	)
Net purchases of property and equipment		—			(22.2	)		(16.7	)		—			(38.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(80.4	)		—			(80.4	)
Dividends and returns of capital received from (contributions to) unconsolidated entities		(759.2	)		299.2			714.8			(254.8	)		—
Net change in other investments		(0.2	)		(148.4	)		(1.6	)		(6.9	)		(157.1	)
Net cash provided by (used in) investing activities		(759.4	)		(938.9	)		547.9			(460.9	)		(1,611.3	)
Financing activities
Issuance of common stock		28.9			—			—			—			28.9
Acquisition of treasury stock		(272.7	)		—			—			—			(272.7	)
Proceeds from financing element derivatives		—			51.8			—			—			51.8
Payments for financing element derivatives		—			(49.9	)		—			—			(49.9	)
Excess tax benefits from share-based payment arrangements		—			5.1			5.7			—			10.8
Dividends to common stockholders		(231.3	)		—			—			—			(231.3	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		1,483.90			—			9.5			—			1,493.40
Principal repayments of long-term debt		(440.8	)		—			(90.9	)		81.1			(450.6	)
Net repayments of short-term borrowings		—			—			(68.8	)		—			(68.8	)
Capital received from (dividends and capital paid to) parent		—			(714.8	)		460			254.8			—
Investment contract deposits		—			6,401.20			499.2			—			6,900.40
Investment contract withdrawals		—			(7,519.8	)		(2.8	)		—			(7,522.6	)
Net increase in banking operation deposits		—			—			32			—			32
Other		—			(14.6	)		—			—			(14.6	)
Net cash provided by (used in) financing activities		535			(1,841.0	)		843.9			335.9			(126.2	)
Net increase (decrease) in cash and cash equivalents		(19.6	)		353.9			1,009.30			(0.3	)		1,343.30
Cash and cash equivalents at beginning of period		226.7			1,344.50			1,277.60			(14.9	)		2,833.90
Cash and cash equivalents at end of period	$	207.1		$	1,698.40		$	2,286.90		$	(15.2	)	$	4,177.20
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2011
	Principal			Principal Life			Principal			Eliminations			Principal
	Financial			Insurance			Financial						Financial
	Group, Inc.			Company			Services, Inc. and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(73.3	)	$	2,495.50		$	304.7		$	(13.6	)	$	2,713.30
Investing activities
Available-for-sale securities:
Purchases		(4.4	)		(6,047.2	)		(696.8	)		6			(6,742.4	)
Sales		200			689.5			116.2			(25.0	)		980.7
Maturities		4.4			5,037.00			719.4			—			5,760.80
Mortgage loans acquired or originated		—			(1,372.7	)		(169.0	)		56.8			(1,484.9	)
Mortgage loans sold or repaid		—			1,548.60			339.3			(94.8	)		1,793.10
Real estate acquired		—			(0.3	)		(129.6	)		—			(129.9	)
Net purchases of property and equipment		—			(46.7	)		(10.2	)		—			(56.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(270.5	)		—			(270.5	)
Dividends and returns of capital received from unconsolidated entities		506.5			327.9			756.5			(1,590.9	)		—
Net change in other investments		(0.2	)		(48.1	)		84.5			(88.3	)		(52.1	)
Net cash provided by (used in) investing activities		706.3			88			739.8			(1,736.2	)		(202.1	)
Financing activities
Issuance of common stock		25.9			—			—			—			25.9
Acquisition of treasury stock		(556.4	)		—			—			—			(556.4	)
Proceeds from financing element derivatives		—			75.9			—			—			75.9
Payments for financing element derivatives		—			(46.5	)		—			—			(46.5	)
Excess tax benefits from share-based payment arrangements		—			0.8			1.2			—			2
Dividends to common stockholders		(213.7	)		—			—			—			(213.7	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Principal repayments of long-term debt		—			—			(69.4	)		57.2			(12.2	)
Net proceeds from short-term borrowings		—			—			3.2			—			3.2
Dividends and capital paid to parent		—			(756.5	)		(834.4	)		1,590.90			—
Investment contract deposits		—			5,868.70			433.4			—			6,302.10
Investment contract withdrawals		—			(7,076.7	)		(2.3	)		—			(7,079.0	)
Net decrease in banking operation deposits		—			—			(18.5	)		—			(18.5	)
Other		—			(4.5	)		—			—			(4.5	)
Net cash used in financing activities		(777.2	)		(1,938.8	)		(486.8	)		1,648.10			(1,554.7	)
Net increase (decrease) in cash and cash equivalents		(144.2	)		644.7			557.7			(101.7	)		956.5
Cash and cash equivalents at beginning of period		370.9			699.8			719.9			86.8			1,877.40
Cash and cash equivalents at end of period	$	226.7		$	1,344.50		$	1,277.60		$	(14.9	)	$	2,833.90
Condensed Consolidating Financial Information, Shelf Registration Guarantor (Table)	'
	Condensed Consolidating Statements of Financial Position
	December 31, 2013
		Principal			Principal			Principal Life			Eliminations			Principal
		Financial			Financial			Insurance Company						Financial
		Group, Inc.			Services, Inc.			and Other						Group, Inc.
		Parent Only			Only			Subsidiaries						Consolidated
								Combined
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	—		$	—		$	48,757.10		$	—		$	48,757.10
	Fixed maturities, trading		—			—			563.1			—			563.1
	Equity securities, available-for-sale		—			—			110.5			—			110.5
	Equity securities, trading		—			—			716.9			—			716.9
	Mortgage loans		—			—			11,533.60			—			11,533.60
	Real estate		—			—			1,271.60			—			1,271.60
	Policy loans		—			—			859.7			—			859.7
	Investment in unconsolidated entities		11,956.20			11,647.60			879.8			(23,603.6	)		880
	Other investments		9.3			72.7			1,982.50			(0.1	)		2,064.40
	Cash and cash equivalents		131.5			688.7			2,384.00			(832.4	)		2,371.80
	Accrued investment income		—			—			532.1			—			532.1
	Premiums due and other receivables		—			0.1			2,330.40			(1,089.5	)		1,241.00
	Deferred acquisition costs		—			—			3,077.00			—			3,077.00
	Property and equipment		—			—			500.7			—			500.7
	Goodwill		—			—			1,100.30			—			1,100.30
	Other intangibles		—			—			1,459.00			—			1,459.00
	Separate account assets		—			—			130,018.40			—			130,018.40
	Other assets		59.2			94.8			1,181.00			(200.8	)		1,134.20
	Total assets	$	12,156.20		$	12,503.90		$	209,257.70		$	(25,726.4	)	$	208,191.40
	Liabilities
	Contractholder funds	$	—		$	—		$	35,958.30		$	—		$	35,958.30
	Future policy benefits and claims		—			—			22,626.20			—			22,626.20
	Other policyholder funds		—			—			758.9			—			758.9
	Short-term debt		—			—			443			(292.4	)		150.6
	Long-term debt		2,448.80			—			1,236.90			(1,084.3	)		2,601.40
	Income taxes currently payable		—			2.8			44.7			(42.3	)		5.2
	Deferred income taxes		—			—			979.6			(155.6	)		824
	Separate account liabilities		—			—			130,018.40			—			130,018.40
	Other liabilities		23.2			544.9			5,204.10			(548.0	)		5,224.20
	Total liabilities		2,472.00			547.7			197,270.10			(2,122.6	)		198,167.20
	Redeemable noncontrolling interest		—			—			247.2			—			247.2
	Stockholders' equity
	Series A preferred stock		—			—			—			—			—
	Series B preferred stock		0.1			—			—			—			0.1
	Common stock		4.6			—			17.8			(17.8	)		4.6
	Additional paid-in capital		9,798.90			9,163.70			9,057.10			(18,220.8	)		9,798.90
	Retained earnings		5,405.40			2,578.20			2,387.20			(4,965.4	)		5,405.40
	Accumulated other comprehensive income		183.2			214.3			187.5			(401.8	)		183.2
	Treasury stock, at cost		(5,708.0	)		—			(2.0	)		2			(5,708.0	)
	Total stockholders' equity attributable to PFG		9,684.20			11,956.20			11,647.60			(23,603.8	)		9,684.20
	Noncontrolling interest		—			—			92.8			—			92.8
	Total stockholders' equity		9,684.20			11,956.20			11,740.40			(23,603.8	)		9,777.00
	Total liabilities and stockholders' equity	$	12,156.20		$	12,503.90		$	209,257.70		$	(25,726.4	)	$	208,191.40
	Condensed Consolidating Statements of Financial Position
	December 31, 2012
		Principal			Principal			Principal Life			Eliminations			Principal
		Financial			Financial			Insurance Company						Financial
		Group, Inc.			Services, Inc.			and Other						Group, Inc.
		Parent Only			Only			Subsidiaries						Consolidated
								Combined
		(in millions)
	Assets
	Fixed maturities, available-for-sale	$	—		$	—		$	50,939.30		$	—		$	50,939.30
	Fixed maturities, trading		10.5			—			616.2			—			626.7
Equity securities, available-for-sale		—			—			136.5			—			136.5
Equity securities, trading		—			—			252.8			—			252.8
Mortgage loans		—			—			11,519.70			—			11,519.70
Real estate		—			—			1,180.30			—			1,180.30
Policy loans		—			—			864.9			—			864.9
Investment in unconsolidated entities		11,853.30			10,632.10			860.2			(22,476.6	)		869
Other investments		11.1			39.6			2,371.40			—			2,422.10
Cash and cash equivalents		207.1			612.5			4,241.30			(883.7	)		4,177.20
Accrued investment income		—			—			584.4			—			584.4
Premiums due and other receivables		0.1			1,122.10			2,206.70			(2,244.5	)		1,084.40
Deferred acquisition costs		—			—			2,590.00			—			2,590.00
Property and equipment		—			—			464.2			—			464.2
Goodwill		—			—			543.4			—			543.4
Other intangibles		—			—			914.7			—			914.7
Separate account assets		—			—			81,653.80			—			81,653.80
Other assets		78			51			1,003.50			(125.7	)		1,006.80
Total assets	$	12,160.10		$	12,457.30		$	162,943.30		$	(25,730.5	)	$	161,830.20
Liabilities
Contractholder funds	$	—		$	—		$	37,786.50		$	—		$	37,786.50
Future policy benefits and claims		—			—			22,436.20			—			22,436.20
Other policyholder funds		—			—			716.4			—			716.4
Short-term debt		—			—			2,564.10			(2,523.3	)		40.8
Long-term debt		2,448.60			—			222.7			—			2,671.30
Income taxes currently payable		—			0.1			47.2			(32.0	)		15.3
Deferred income taxes		—			—			686.1			(86.1	)		600
Separate account liabilities		—			—			81,653.80			—			81,653.80
Other liabilities		28.1			603.9			6,117.80			(603.7	)		6,146.10
Total liabilities		2,476.70			604			152,230.80			(3,245.1	)		152,066.40
Redeemable noncontrolling interest		—			—			60.4			—			60.4
Stockholders' equity
Series A preferred stock		—			—			—			—			—
Series B preferred stock		0.1			—			—			—			0.1
Common stock		4.5			—			17.8			(17.8	)		4.5
Additional paid-in capital		9,730.90			9,393.80			8,287.70			(17,681.5	)		9,730.90
Retained earnings		4,862.00			1,783.40			1,666.70			(3,450.1	)		4,862.00
Accumulated other comprehensive income		640.3			676.1			661.9			(1,338.0	)		640.3
Treasury stock, at cost		(5,554.4	)		—			(2.0	)		2			(5,554.4	)
Total stockholders' equity attributable to PFG		9,683.40			11,853.30			10,632.10			(22,485.4	)		9,683.40
Noncontrolling interest		—			—			20			—			20
Total stockholders' equity		9,683.40			11,853.30			10,652.10			(22,485.4	)		9,703.40
Total liabilities and stockholders' equity	$	12,160.10		$	12,457.30		$	162,943.30		$	(25,730.5	)	$	161,830.20
Condensed Consolidating Statements of Operations
For the year ended December 31, 2013
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Revenues
Premiums and other considerations	$	—		$	—		$	3,154.10		$	—		$	3,154.10
Fees and other revenues		—			1			3,250.20			(29.0	)		3,222.20
Net investment income		0.4			1.3			3,136.50			0.2			3,138.40
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		6.3			4.6			(120.1	)		—			(109.2	)
Total other-than-temporary impairment losses on available-for-sale securities		—			—			(91.5	)		—			(91.5	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income		—			—			(24.5	)		—			(24.5	)
Net impairment losses on available-for-sale securities		—			—			(116.0	)		—			(116.0	)
Net realized capital gains (losses)		6.3			4.6			(236.1	)		—			(225.2	)
Total revenues		6.7			6.9			9,304.70			(28.8	)		9,289.50
Expenses
Benefits, claims and settlement expenses		—			—			4,683.60			—			4,683.60
Dividends to policyholders		—			—			189			—			189
Operating expenses		140.5			9			3,172.20			(28.8	)		3,292.90
Total expenses		140.5			9			8,044.80			(28.8	)		8,165.50
Income (loss) before income taxes		(133.8	)		(2.1	)		1,259.90			—			1,124.00
Income taxes (benefits)		(54.0	)		(2.9	)		244.8			—			187.9
Equity in the net income of subsidiaries		992.5			991.7			—			(1,984.2	)		—
Net income		912.7			992.5			1,015.10			(1,984.2	)		936.1
Net income attributable to noncontrolling interest		—			—			23.4			—			23.4
Net income attributable to PFG		912.7			992.5			991.7			(1,984.2	)		912.7
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	879.7		$	992.5		$	991.7		$	(1,984.2	)	$	879.7
Net income	$	912.7		$	992.5		$	1,015.10		$	(1,984.2	)	$	936.1
Other comprehensive loss		(450.1	)		(476.4	)		(489.3	)		943.9			(471.9	)
Comprehensive income	$	462.6		$	516.1		$	525.8		$	(1,040.3	)	$	464.2
Condensed Consolidating Statements of Operations
For the year ended December 31, 2012
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Revenues
Premiums and other considerations	$	—		$	—		$	3,219.40		$	—		$	3,219.40
Fees and other revenues		0.5			—			2,627.30			(1.1	)		2,626.70
Net investment income		3			0.4			3,250.80			0.7			3,254.90
Net realized capital gains, excluding impairment losses on available-for-sale securities		0.3			3			229.6			(0.2	)		232.7
Total other-than-temporary impairment losses on available-for-sale securities		—			—			(135.9	)		—			(135.9	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to other comprehensive income		—			—			17.3			—			17.3
Net impairment losses on available-for-sale securities		—			—			(118.6	)		—			(118.6	)
Net realized capital gains		0.3			3			111			(0.2	)		114.1
Total revenues		3.8			3.4			9,208.50			(0.6	)		9,215.10
Expenses
Benefits, claims and settlement expenses		—			—			5,123.90			—			5,123.90
Dividends to policyholders		—			—			197.7			—			197.7
Operating expenses		170.2			9.3			2,754.60			(0.6	)		2,933.50
Total expenses		170.2			9.3			8,076.20			(0.6	)		8,255.10
Income (loss) before income taxes		(166.4	)		(5.9	)		1,132.30			—			960
Income taxes (benefits)		(67.6	)		(6.9	)		209.1			—			134.6
Equity in the net income of subsidiaries		905.4			904.4			—			(1,809.8	)		—
Net income		806.6			905.4			923.2			(1,809.8	)		825.4
Net income attributable to noncontrolling interest		—			—			18.8			—			18.8
Net income attributable to PFG		806.6			905.4			904.4			(1,809.8	)		806.6
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	773.6		$	905.4		$	904.4		$	(1,809.8	)	$	773.6
Net income	$	806.6		$	905.4		$	923.2		$	(1,809.8	)	$	825.4
Other comprehensive income		321.2			366.3			353.7			(671.1	)		370.1
Comprehensive income	$	1,127.80		$	1,271.70		$	1,276.90		$	(2,480.9	)	$	1,195.50
Condensed Consolidating Statements of Operations
For the year ended December 31, 2011
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Revenues
Premiums and other considerations	$	—		$	—		$	2,891.00		$	—		$	2,891.00
Fees and other revenues		0.2			—			2,529.50			(3.0	)		2,526.70
Net investment income (loss)		(12.0	)		(3.2	)		3,387.50			3			3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities		—			(0.1	)		75.1			—			75
Total other-than-temporary impairment losses on available-for-sale securities		—			—			(147.6	)		—			(147.6	)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified from other comprehensive income		—			—			(49.7	)		—			(49.7	)
Net impairment losses on available-for-sale securities		—			—			(197.3	)		—			(197.3	)
Net realized capital losses		—			(0.1	)		(122.2	)		—			(122.3	)
Total revenues		(11.8	)		(3.3	)		8,685.80			—			8,670.70
Expenses
Benefits, claims and settlement expenses		—			—			4,616.60			—			4,616.60
Dividends to policyholders		—			—			210.2			—			210.2
Operating expenses		116			1.7			2,853.40			—			2,971.10
Total expenses		116			1.7			7,680.20			—			7,797.90
Income (loss) before income taxes		(127.8	)		(5.0	)		1,005.60			—			872.8
Income taxes (benefits)		(50.4	)		(9.9	)		258.6			—			198.3
Equity in the net income of subsidiaries		715.7			710.8			—			(1,426.5	)		—
Net income		638.3			715.7			747			(1,426.5	)		674.5
Net income attributable to noncontrolling interest		—			—			36.2			—			36.2
Net income attributable to PFG		638.3			715.7			710.8			(1,426.5	)		638.3
Preferred stock dividends		33			—			—			—			33
Net income available to common stockholders	$	605.3		$	715.7		$	710.8		$	(1,426.5	)	$	605.3
Net income	$	638.3		$	715.7		$	747		$	(1,426.5	)	$	674.5
Other comprehensive loss		(34.5	)		(44.0	)		(51.1	)		89			(40.6	)
Comprehensive income	$	603.8		$	671.7		$	695.9		$	(1,337.5	)	$	633.9
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2013
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(42.8	)	$	1,019.00		$	2,340.20		$	(1,095.2	)	$	2,221.20
Investing activities
Available-for-sale securities:
Purchases		—			—			(9,025.2	)		—			(9,025.2	)
Sales		—			—			1,919.10			—			1,919.10
Maturities		—			—			7,359.20			—			7,359.20
Mortgage loans acquired or originated		—			—			(2,192.9	)		—			(2,192.9	)
Mortgage loans sold or repaid		—			—			2,095.10			—			2,095.10
Real estate acquired		—			—			(85.6	)		—			(85.6	)
Net purchases of property and equipment		—			—			(59.4	)		—			(59.4	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(1,268.3	)		—			(1,268.3	)
Dividends and returns of capital received from (contributions to) unconsolidated entities		319.5			(594.6	)		—			275.1			—
Net change in other investments		(3.1	)		(28.7	)		63.5			—			31.7
Net cash provided by (used in) investing activities		316.4			(623.3	)		(1,194.5	)		275.1			(1,226.3	)
Financing activities
Issuance of common stock		125.8			—			—			—			125.8
Acquisition of treasury stock		(153.6	)		—			—			—			(153.6	)
Proceeds from financing element derivatives		—			—			47			—			47
Payments for financing element derivatives		—			—			(48.0	)		—			(48.0	)
Excess tax benefits from share-based payment arrangements		—			—			10.1			—			10.1
Purchase of subsidiary shares from noncontrolling interest		—			—			(52.9	)		—			(52.9	)
Sale of subsidiary shares to noncontrolling interest		—			—			31.8			—			31.8
Dividends to common stockholders		(288.4	)		—			—			—			(288.4	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		—			—			1,122.50			(1,084.3	)		38.2
Principal repayments of long-term debt		—			—			(218.2	)		—			(218.2	)
Net proceeds from (repayments of) short-term borrowings		—			—			(2,122.8	)		2,230.80			108
Capital received from (dividends and capital paid to) parent		—			(319.5	)		594.6			(275.1	)		—
Investment contract deposits		—			—			6,716.30			—			6,716.30
Investment contract withdrawals		—			—			(8,852.7	)		—			(8,852.7	)
Net decrease in banking operation deposits		—			—			(225.7	)		—			(225.7	)
Other		—			—			(5.0	)		—			(5.0	)
Net cash used in financing activities		(349.2	)		(319.5	)		(3,003.0	)		871.4			(2,800.3	)
Net increase (decrease) in cash and cash equivalents		(75.6	)		76.2			(1,857.3	)		51.3			(1,805.4	)
Cash and cash equivalents at beginning of period		207.1			612.5			4,241.30			(883.7	)		4,177.20
Cash and cash equivalents at end of period	$	131.5		$	688.7		$	2,384.00		$	(832.4	)	$	2,371.80
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2012
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	204.8		$	(1,145.0	)	$	1,762.00		$	2,259.00		$	3,080.80
Investing activities
Available-for-sale securities:
Purchases		—			—			(8,263.9	)		—			(8,263.9	)
Sales		—			—			1,303.70			—			1,303.70
Maturities		—			—			6,647.50			—			6,647.50
Mortgage loans acquired or originated		—			—			(2,538.4	)		—			(2,538.4	)
Mortgage loans sold or repaid		—			—			1,668.00			—			1,668.00
Real estate acquired		—			—			(151.8	)		—			(151.8	)
Net purchases of property and equipment		—			—			(38.9	)		—			(38.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(80.4	)		—			(80.4	)
Dividends and returns of capital received from (contributions to) unconsolidated entities		(759.2	)		381			—			378.2			—
Net change in other investments		(0.2	)		(35.1	)		(121.8	)		—			(157.1	)
Net cash provided by (used in) investing activities		(759.4	)		345.9			(1,576.0	)		378.2			(1,611.3	)
Financing activities
Issuance of common stock		28.9			—			—			—			28.9
Acquisition of treasury stock		(272.7	)		—			—			—			(272.7	)
Proceeds from financing element derivatives		—			—			51.8			—			51.8
Payments for financing element derivatives		—			—			(49.9	)		—			(49.9	)
Excess tax benefits from share-based payment arrangements		—			—			10.8			—			10.8
Dividends to common stockholders		(231.3	)		—			—			—			(231.3	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Issuance of long-term debt		1,483.90			—			9.5			—			1,493.40
Principal repayments of long-term debt		(440.8	)		—			(9.8	)		—			(450.6	)
Net proceeds from (repayments of) short-term borrowings		—			(50.0	)		2,240.80			(2,259.6	)		(68.8	)
Capital received from (dividends and capital paid to) parent		—			759.2			(381.0	)		(378.2	)		—
Investment contract deposits		—			—			6,900.40			—			6,900.40
Investment contract withdrawals		—			—			(7,522.6	)		—			(7,522.6	)
Net increase in banking operation deposits		—			—			32			—			32
Other		—			—			(14.6	)		—			(14.6	)
Net cash provided by (used in) financing activities		535			709.2			1,267.40			(2,637.8	)		(126.2	)
Net increase (decrease) in cash and cash equivalents		(19.6	)		(89.9	)		1,453.40			(0.6	)		1,343.30
Cash and cash equivalents at beginning of period		226.7			702.4			2,787.90			(883.1	)		2,833.90
Cash and cash equivalents at end of period	$	207.1		$	612.5		$	4,241.30		$	(883.7	)	$	4,177.20
Condensed Consolidating Statements of Cash Flows
For the year ended December 31, 2011
	Principal			Principal			Principal Life			Eliminations			Principal
	Financial			Financial			Insurance						Financial
	Group, Inc.			Services, Inc.			Company and						Group, Inc.
	Parent Only			Only			Other Subsidiaries						Consolidated
							Combined
	(in millions)
Operating activities
Net cash provided by (used in) operating activities	$	(73.3	)	$	70.5		$	2,795.00		$	(78.9	)	$	2,713.30
Investing activities
Available-for-sale securities:
Purchases		(4.4	)		—			(6,738.0	)		—			(6,742.4	)
Sales		200			—			780.7			—			980.7
Maturities		4.4			—			5,756.40			—			5,760.80
Mortgage loans acquired or originated		—			—			(1,484.9	)		—			(1,484.9	)
Mortgage loans sold or repaid		—			—			1,793.10			—			1,793.10
Real estate acquired		—			—			(129.9	)		—			(129.9	)
Net purchases of property and equipment		—			—			(56.9	)		—			(56.9	)
Purchases of interests in subsidiaries, net of cash acquired		—			—			(270.5	)		—			(270.5	)
Dividends and returns of capital received from unconsolidated entities		506.5			624.1			—			(1,130.6	)		—
Net change in other investments		(0.2	)		(5.4	)		(46.5	)		—			(52.1	)
Net cash provided by (used in) investing activities		706.3			618.7			(396.5	)		(1,130.6	)		(202.1	)
Financing activities
Issuance of common stock		25.9			—			—			—			25.9
Acquisition of treasury stock		(556.4	)		—			—			—			(556.4	)
Proceeds from financing element derivatives		—			—			75.9			—			75.9
Payments for financing element derivatives		—			—			(46.5	)		—			(46.5	)
Excess tax benefits from share-based payment arrangements		—			—			2			—			2
Dividends to common stockholders		(213.7	)		—			—			—			(213.7	)
Dividends to preferred stockholders		(33.0	)		—			—			—			(33.0	)
Principal repayments of long-term debt		—			—			(12.2	)		—			(12.2	)
Net proceeds from (repayments of) short-term borrowings		—			—			(27.5	)		30.7			3.2
Dividends and capital paid to parent		—			(506.5	)		(624.1	)		1,130.60			—
Investment contract deposits		—			—			6,302.10			—			6,302.10
Investment contract withdrawals		—			—			(7,079.0	)		—			(7,079.0	)
Net decrease in banking operation deposits		—			—			(18.5	)		—			(18.5	)
Other		—			—			(4.5	)		—			(4.5	)
Net cash used in financing activities		(777.2	)		(506.5	)		(1,432.3	)		1,161.30			(1,554.7	)
Net increase (decrease) in cash and cash equivalents		(144.2	)		182.7			966.2			(48.2	)		956.5
Cash and cash equivalents at beginning of period		370.9			519.7			1,821.70			(834.9	)		1,877.40
Cash and cash equivalents at end of period	$	226.7		$	702.4		$	2,787.90		$	(883.1	)	$	2,833.90

Nature_of_Operations_and_Signi3

Nature of Operations and Significant Accounting Policies (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Assets	'	'	'	'
Fixed maturities, available-for-sale	$48,757.10	$50,939.30	'	'
Fixed maturities, trading	563.1	626.7	'	'
Equity securities, available-for-sale	110.5	136.5	'	'
Equity securities, trading	716.9	252.8	'	'
Mortgage loans	11,533.60	11,519.70	'	'
Real estate	1,271.60	1,180.30	'	'
Policy loans	859.7	864.9	'	'
Other investments	2,944.40	3,291.10	'	'
Total investments	66,756.90	68,811.30	'	'
Cash and cash equivalents	2,371.80	4,177.20	2,833.90	1,877.40
Accrued investment income	532.1	584.4	'	'
Premiums due and other receivables	1,241	1,084.40	'	'
Deferred acquisition costs	3,077	2,590	2,358.10	2,442.20
Property and equipment	500.7	464.2	'	'
Goodwill	1,100.30	543.4	482.3	'
Other intangibles	1,459	914.7	'	'
Separate account assets	130,018.40	81,653.80	'	'
Other assets	1,134.20	1,006.80	'	'
Total assets	208,191.40	161,830.20	'	'
Liabilities	'	'	'	'
Contractholder funds	35,958.30	37,786.50	'	'
Future policy benefits and claims	22,626.20	22,436.20	'	'
Other policyholder funds	758.9	716.4	'	'
Short-term debt	150.6	40.8	'	'
Long-term debt	2,601.40	2,671.30	'	'
Income taxes currently payable	5.2	15.3	'	'
Deferred income taxes	824	600	'	'
Separate account liabilities	130,018.40	81,653.80	'	'
Other liabilities	5,224.20	6,146.10	'	'
Total liabilities	198,167.20	152,066.40	'	'
Redeemable noncontrolling interest	247.2	60.4	22.2	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income (loss)	183.2	640.3	'	'
Treasury stock, at cost	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Noncontrolling interest	92.8	20	'	'
Total stockholders' equity	9,777	9,703.40	9,306.20	9,246.80
Total liabilities and stockholders' equity	208,191.40	161,830.20	'	'
Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
Total stockholders' equity	0	0	0	0
Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	0.1	0.1	0.1	'
Total stockholders' equity	0.1	0.1	0.1	0.1
As originally reported	'	'	'	'
Assets	'	'	'	'
Fixed maturities, available-for-sale	'	50,939.30	'	'
Fixed maturities, trading	'	626.7	'	'
Equity securities, available-for-sale	'	136.5	'	'
Equity securities, trading	'	252.8	'	'
Mortgage loans	'	11,519.70	'	'
Real estate	'	1,180.30	'	'
Policy loans	'	864.9	'	'
Other investments	'	3,291.10	'	'
Total investments	'	68,811.30	'	'
Cash and cash equivalents	'	4,177.20	'	'
Accrued investment income	'	584.4	'	'
Premiums due and other receivables	'	1,084.40	'	'
Deferred acquisition costs	'	2,673.80	'	'
Property and equipment	'	464.2	'	'
Goodwill	'	543.4	'	'
Other intangibles	'	927.2	'	'
Separate account assets	'	81,653.80	'	'
Other assets	'	1,006.80	'	'
Total assets	'	161,926.50	'	'
Liabilities	'	'	'	'
Contractholder funds	'	37,786.50	'	'
Future policy benefits and claims	'	22,436.20	'	'
Other policyholder funds	'	716.4	'	'
Short-term debt	'	40.8	'	'
Long-term debt	'	2,671.30	'	'
Income taxes currently payable	'	15.3	'	'
Deferred income taxes	'	626.5	'	'
Separate account liabilities	'	81,653.80	'	'
Other liabilities	'	6,146.10	'	'
Total liabilities	'	152,092.90	'	'
Redeemable noncontrolling interest	'	60.4	'	'
Stockholders' equity	'	'	'	'
Common stock	'	4.5	'	'
Additional paid-in capital	'	9,730.90	'	'
Retained earnings (accumulated deficit)	'	4,940.20	'	'
Accumulated other comprehensive income (loss)	'	631.9	'	'
Treasury stock, at cost	'	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	'	9,753.20	'	'
Noncontrolling interest	'	20	'	'
Total stockholders' equity	'	9,773.20	'	'
Total liabilities and stockholders' equity	'	161,926.50	'	'
As originally reported | Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
As originally reported | Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	$0.10	$0.10	'

Nature_of_Operations_and_Signi4

Nature of Operations and Significant Accounting Policies (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	$700.10	$1,158.20	$681.30	$679.80	$3,154.10	$3,219.40	$2,891
Fees and other revenues	'	'	'	'	717.6	675	636.1	598	3,222.20	2,626.70	2,526.70
Net investment income (loss)	'	'	'	'	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	56.3	122.1	32.2	22.1	-109.2	232.7	75
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	-9.5	-43.6	-49.1	-33.7	-91.5	-135.9	-147.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	-13.9	9.2	17.1	4.9	-24.5	17.3	-49.7
Net impairment losses on available-for-sale securities	'	'	'	'	-23.4	-34.4	-32	-28.8	-116	-118.6	-197.3
Net realized capital gains (losses)	'	'	'	'	32.9	87.7	0.2	-6.7	-225.2	114.1	-122.3
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	1,154.40	1,647	1,110	1,212.50	4,683.60	5,123.90	4,616.60
Dividends to policyholders	'	'	'	'	48.2	49.7	49.5	50.3	189	197.7	210.2
Operating expenses	'	'	'	'	832.4	816.4	729.6	555.1	3,292.90	2,933.50	2,971.10
Total expenses	2,362.70	1,919.30	1,945	1,938.50	2,035	2,513.10	1,889.10	1,817.90	8,165.50	8,255.10	7,797.90
Income (loss) before income taxes	'	'	'	'	260.9	191.6	229.5	278	1,124	960	872.8
Income taxes (benefits)	'	'	'	'	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Net income (loss) attributable to noncontrolling interest	'	'	'	'	3.5	3.4	2.7	9.2	23.4	18.8	36.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	223.2	195.4	175.9	212.1	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	33	33	33
Net income (loss) available to common stockholders	233.4	245.7	222.3	178.3	214.9	187.2	167.6	203.9	879.7	773.6	605.3
Earnings per common share	'	'	'	'	'	'	'	'	'	'	'
Basic earnings per common share (in dollars per share)	$0.79	$0.83	$0.76	$0.61	$0.72	$0.64	$0.56	$0.68	$2.99	$2.60	$1.92
Diluted earnings per common share (in dollars per share)	$0.78	$0.82	$0.75	$0.61	$0.72	$0.63	$0.56	$0.68	$2.95	$2.58	$1.91
As originally reported	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	700.1	1,158.20	681.3	679.8	'	3,219.40	2,891
Fees and other revenues	'	'	'	'	717.6	675	636.1	598	'	2,626.70	2,526.70
Net investment income (loss)	'	'	'	'	845.3	783.8	801	824.8	'	3,254.90	3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	56.3	122.1	32.2	22.1	'	232.7	75
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	-9.5	-43.6	-49.1	-33.7	'	-135.9	-147.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	-13.9	9.2	17.1	4.9	'	17.3	-49.7
Net impairment losses on available-for-sale securities	'	'	'	'	-23.4	-34.4	-32	-28.8	'	-118.6	-197.3
Net realized capital gains (losses)	'	'	'	'	32.9	87.7	0.2	-6.7	'	114.1	-122.3
Total revenues	'	'	'	'	2,295.90	2,704.70	2,118.60	2,095.90	'	9,215.10	8,670.70
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	1,154.40	1,647	1,110	1,212.50	'	5,123.90	4,616.60
Dividends to policyholders	'	'	'	'	48.2	49.7	49.5	50.3	'	197.7	210.2
Operating expenses	'	'	'	'	827.4	826.6	724.1	556	'	2,934.10	2,950.80
Total expenses	'	'	'	'	2,030	2,523.30	1,883.60	1,818.80	'	8,255.70	7,777.60
Income (loss) before income taxes	'	'	'	'	265.9	181.4	235	277.1	'	959.4	893.1
Income taxes (benefits)	'	'	'	'	35.5	-9.9	50.9	58.2	'	134.7	204.2
Net income (loss)	'	'	'	'	230.4	191.3	184.1	218.9	'	824.7	688.9
Net income (loss) attributable to noncontrolling interest	'	'	'	'	3.5	3.4	2.7	9.2	'	18.8	36.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	226.9	187.9	181.4	209.7	'	805.9	652.7
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	'	33	33
Net income (loss) available to common stockholders	'	'	'	'	$218.60	$179.70	$173.10	$201.50	'	$772.90	$619.70
Earnings per common share	'	'	'	'	'	'	'	'	'	'	'
Basic earnings per common share (in dollars per share)	'	'	'	'	$0.74	$0.61	$0.58	$0.67	'	$2.60	$1.97
Diluted earnings per common share (in dollars per share)	'	'	'	'	$0.74	$0.60	$0.58	$0.66	'	$2.57	$1.95

Nature_of_Operations_and_Signi5

Nature of Operations and Significant Accounting Policies (Details 3) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated statements of comprehensive income	'	'	'	'	'	'	'	'	'	'	'
Net income (loss)	$250.40	$259.10	$236.60	$190	$226.70	$198.80	$178.60	$221.30	$936.10	$825.40	$674.50
Net unrealized gains (losses) on available-for-sale securities	'	'	'	'	'	'	'	'	-540.2	557.6	208.6
Noncredit component of impairment losses on fixed maturities, available-for-sale	'	'	'	'	'	'	'	'	6.9	-6.7	31
Net unrealized gains (losses) on derivative instruments	'	'	'	'	'	'	'	'	-1.8	-43.6	23.6
Foreign currency translation adjustment	'	'	'	'	'	'	'	'	-269.4	-9.8	-130.9
Net unrecognized postretirement benefit obligation	'	'	'	'	'	'	'	'	332.6	-127.4	-172.9
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-471.9	370.1	-40.6
Comprehensive income (loss)	'	'	'	'	'	'	'	'	464.2	1,195.50	633.9
Comprehensive income (loss) attributable to noncontrolling interest	'	'	'	'	'	'	'	'	8.6	20	35.7
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	455.6	1,175.50	598.2
As originally reported	'	'	'	'	'	'	'	'	'	'	'
Consolidated statements of comprehensive income	'	'	'	'	'	'	'	'	'	'	'
Net income (loss)	'	'	'	'	230.4	191.3	184.1	218.9	'	824.7	688.9
Net unrealized gains (losses) on available-for-sale securities	'	'	'	'	'	'	'	'	'	557.6	208.6
Noncredit component of impairment losses on fixed maturities, available-for-sale	'	'	'	'	'	'	'	'	'	-6.7	31
Net unrealized gains (losses) on derivative instruments	'	'	'	'	'	'	'	'	'	-43.6	23.6
Foreign currency translation adjustment	'	'	'	'	'	'	'	'	'	-4.8	-139.5
Net unrecognized postretirement benefit obligation	'	'	'	'	'	'	'	'	'	-127.4	-172.9
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	'	375.1	-49.2
Comprehensive income (loss)	'	'	'	'	'	'	'	'	'	1,199.80	639.7
Comprehensive income (loss) attributable to noncontrolling interest	'	'	'	'	'	'	'	'	'	20	35.7
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	'	$1,179.80	$604

Nature_of_Operations_and_Signi6

Nature of Operations and Significant Accounting Policies (Details 4) (USD $)	3 Months Ended				12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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	$87,000,000	'	'	'	$182,300,000	$87,000,000	'
Contractholder and Policyholder Liabilities	'	'	'	'	'	'	'
Participating business as a percentage of life insurance in force (as a percent)	13.00%	'	'	'	12.00%	13.00%	15.00%
Participating business as a percentage of life insurance policies in force (as a percent)	47.00%	'	'	'	43.00%	47.00%	50.00%
Participating business as a percentage of life insurance premiums (as a percent)	'	'	'	'	40.00%	43.00%	47.00%
Long-Term Debt	'	'	'	'	'	'	'
Minimum maturity period at date of issuance for debt to be classified as long-term	'	'	'	'	'1 year	'	'
Reinsurance	'	'	'	'	'	'	'
Life insurance in force of largest exposure to a single third-party reinsurer in individual life insurance business	29,700,000,000	'	'	'	35,900,000,000	29,700,000,000	'
Largest exposure to a single third-party reinsurer in individual life insurance business as percentage of total net individual life insurance in force (as a percent)	18.00%	'	'	'	17.00%	18.00%	'
Reinsurance recoverable of largest exposure to a single third-party reinsurer in individual life insurance business	26,100,000	'	'	'	31,300,000	26,100,000	'
Premiums and other considerations:	'	'	'	'	'	'	'
Premiums and other considerations, Direct	'	'	'	'	3,524,800,000	3,554,100,000	3,205,600,000
Premiums and other considerations, Assumed	'	'	'	'	2,500,000	2,600,000	3,000,000
Premiums and other considerations, Ceded	'	'	'	'	-373,200,000	-337,300,000	-317,600,000
Premiums and other considerations	700,100,000	1,158,200,000	681,300,000	679,800,000	3,154,100,000	3,219,400,000	2,891,000,000
Benefits, claims and settlement expenses:	'	'	'	'	'	'	'
Benefits, claims and settlement expenses, Direct	'	'	'	'	4,933,300,000	5,268,600,000	4,926,500,000
Benefits, claims and settlement expenses, Assumed	'	'	'	'	32,200,000	33,900,000	34,000,000
Benefits, claims and settlement expenses, Ceded	'	'	'	'	-281,900,000	-178,600,000	-343,900,000
Benefits, claims and settlement expenses	1,154,400,000	1,647,000,000	1,110,000,000	1,212,500,000	4,683,600,000	5,123,900,000	4,616,600,000
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	$148,300,000	'	'	'	$223,100,000	$148,300,000	'

Acquisition_Details

Acquisition (Details) (Cuprum, USD $)	0 Months Ended
	Feb. 04, 2013
Business Acquisition	'
Percent of principal shareholders ownership acquired (as a percent)	63.00%
Potential percent of publicly traded shares acquired (as a percent)	37.00%
Percent of business acquired (as a percent)	91.55%
Purchase price of acquired business	$1,300,000,000
Equity securities, available-for-sale	3,200,000
Equity securities, trading	340,500,000
Real estate	1,900,000
Other investments	24,200,000
Cash and cash equivalents	3,500,000
Premiums due and other receivables	1,400,000
Property and equipment	19,600,000
Goodwill	631,800,000
Other intangibles	671,300,000
Separate account assets	33,919,400,000
Other assets	27,300,000
Total assets acquired	35,644,100,000
Short-term debt	5,000,000
Long-term debt	114,600,000
Separate account liabilities	33,919,400,000
Other liabilities	228,000,000
Total liabilities assumed	34,267,000,000
Noncontrolling interest	113,600,000
Net assets acquired	1,263,500,000
Trade names	'
Business Acquisition	'
Acquired Indefinite-lived Intangible Asset, Amount	185,200,000
Customer relationships	'
Business Acquisition	'
Acquired Finite-lived Intangible Asset, Amount	$486,100,000
Acquired Finite-Lived Intangible Asset, Useful Life	'15 years

Acquisition_Details_2

Acquisition (Details 2) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquisition	'	'	'
Total revenues - Pro forma	$9,339.40	$9,424.40	$8,840.30
Net income (loss) - Pro forma	$956.60	$939.30	$753.20
Basic earnings (loss) per common share (in dollars per share) - Pro forma	$3.25	$3.16	$2.39
Diluted earnings (loss) per common share (in dollars per share) - Pro forma	$3.21	$3.13	$2.37

Acquisition_Details_3

Acquisition (Details 3) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition	'	'	'	'	'	'	'	'	'	'	'
Total revenues	$2,672.60	$2,239.60	$2,210.60	$2,166.70	$2,295.90	$2,704.70	$2,118.60	$2,095.90	$9,289.50	$9,215.10	$8,670.70
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Cuprum	'	'	'	'	'	'	'	'	'	'	'
Business Acquisition	'	'	'	'	'	'	'	'	'	'	'
Total revenues	'	'	'	'	'	'	'	'	186.4	'	'
Net income (loss)	'	'	'	'	'	'	'	'	$87	'	'

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Changes in Goodwill	'	'
Beginning balance, Goodwill	$543.40	$482.30
Goodwill from acquisitions	634.4	73.8
Goodwill disposed	-1.4	'
Foreign currency, Goodwill	-80.1	-8.7
Other changes in goodwill	4	-4
Ending balance, Goodwill	1,100.30	543.4
Retirement and Investor Services	'	'
Changes in Goodwill	'	'
Beginning balance, Goodwill	68.6	72.6
Other changes in goodwill	4	-4
Ending balance, Goodwill	72.6	68.6
Principal Global Investors	'	'
Changes in Goodwill	'	'
Beginning balance, Goodwill	239.9	237
Foreign currency, Goodwill	1.2	2.9
Ending balance, Goodwill	241.1	239.9
Principal International	'	'
Changes in Goodwill	'	'
Beginning balance, Goodwill	179.5	127.8
Goodwill from acquisitions	631.8	63.3
Foreign currency, Goodwill	-81.3	-11.6
Ending balance, Goodwill	730	179.5
U.S. Insurance Solutions	'	'
Changes in Goodwill	'	'
Beginning balance, Goodwill	55.4	44.9
Goodwill from acquisitions	2.6	10.5
Goodwill disposed	-1.4	'
Ending balance, Goodwill	$56.60	$55.40

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite Lived Intangible Asset Disclosures	'	'	'
Weighted average remaining expected life of finite lived intangible assets	'14 years	'	'
Gross carrying amount	$872.30	$449.60	'
Accumulated amortization	269.6	230.2	'
Net carrying amount	602.7	219.4	'
Present value of future profits	'	'	'
Finite Lived Intangible Asset Disclosures	'	'	'
Gross carrying amount	13.5	13.5	'
Accumulated amortization	6.7	6.1	'
Net carrying amount	6.8	7.4	'
Other finite lived intangible assets	'	'	'
Finite Lived Intangible Asset Disclosures	'	'	'
Gross carrying amount	858.8	436.1	'
Accumulated amortization	262.9	224.1	'
Net carrying amount	595.9	212	'
Finite lived intangible assets fully amortized during the period	5.2	5	0
Other Finite Lived Intangible Assets	'	'	'
Amortization expense for intangible assets with finite useful lives	48	22.7	20.1
Estimated amortization expense for the next five years	'	'	'
Year 1: Finite lived intangible assets amortization	52.3	'	'
Year 2: Finite lived intangible assets amortization	50.9	'	'
Year 3: Finite lived intangible assets amortization	50.1	'	'
Year 4: Finite lived intangible assets amortization	49.2	'	'
Year 5: Finite lived intangible assets amortization	$48	'	'

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets (Details 3) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Indefinite Lived Intangible Assets	'	'
Net carrying amount of unamortized indefinite lived intangible assets	$856.30	$695.30
WM Advisors, Inc.	'	'
Indefinite Lived Intangible Assets	'	'
Net carrying amount of unamortized indefinite lived intangible assets	608	608
Cuprum | Trade names	'	'
Indefinite Lived Intangible Assets	'	'
Net carrying amount of unamortized indefinite lived intangible assets	$185.20	'

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Carrying amounts of consolidated VIE assets and liabilities	'	'
Fixed maturities, available-for-sale	$48,757.10	$50,939.30
Fixed maturities, trading	563.1	626.7
Equity securities, trading	716.9	252.8
Other investments	2,944.40	3,291.10
Accrued investment income	532.1	584.4
Separate account assets	130,018.40	81,653.80
Total assets	208,191.40	161,830.20
Deferred income taxes	824	600
Separate account liabilities	130,018.40	81,653.80
Other liabilities	5,224.20	6,146.10
Total liabilities	198,167.20	152,066.40
Aggregate consolidated variable interest entities	'	'
Carrying amounts of consolidated VIE assets and liabilities	'	'
Fixed maturities, available-for-sale	272	194.6
Fixed maturities, trading	110.4	110.4
Equity securities, trading	327.2	'
Other investments	68.1	80.3
Accrued investment income	0.9	1.1
Separate account assets	32,824.70	'
Total assets	33,603.30	386.4
Deferred income taxes	1.5	1.8
Separate account liabilities	32,824.70	'
Other liabilities	342.4	302.9
Total liabilities	33,168.60	304.7
Grantor trusts	'	'
Consolidated Variable Interest Entity disclosures	'	'
Number of consolidated variable interest entities	3	'
Carrying amounts of consolidated VIE assets and liabilities	'	'
Fixed maturities, available-for-sale	272	194.6
Accrued investment income	0.3	0.5
Total assets	272.3	195.1
Deferred income taxes	1.5	1.8
Other liabilities	217.2	152.4
Total liabilities	218.7	154.2
Collateralized private investment vehicle	'	'
Consolidated Variable Interest Entity disclosures	'	'
Number of entities for which the reporting entity acts as primary beneficiary	1	'
Carrying amounts of consolidated VIE assets and liabilities	'	'
Fixed maturities, trading	110.4	110.4
Total assets	110.4	110.4
Other liabilities	93.8	104.8
Total liabilities	93.8	104.8
Commercial mortgage-backed securities VIE	'	'
Carrying amounts of consolidated VIE assets and liabilities	'	'
Other investments	68.1	80.3
Accrued investment income	0.6	0.6
Total assets	68.7	80.9
Other liabilities	31.4	45.7
Total liabilities	31.4	45.7
Mandatory retirement savings	'	'
Carrying amounts of consolidated VIE assets and liabilities	'	'
Equity securities, trading	327.2	'
Separate account assets	32,824.70	'
Total assets	33,151.90	'
Separate account liabilities	32,824.70	'
Total liabilities	$32,824.70	'

Variable_Interest_Entities_Det1

Variable Interest Entities (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Sponsored Investment Funds	'	'
Total assets of unconsolidated money market mutual fund variable interest entities	$1,400,000,000	$1,500,000,000
Other investments: Other limited partnership interests	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	123,500,000	136,200,000
Maximum exposure to loss	123,500,000	136,200,000
Available-for-sale | Corporate debt securities	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	523,400,000	523,200,000
Maximum exposure to loss	448,200,000	403,700,000
Available-for-sale | Residential mortgage-backed pass-through securities	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	2,845,200,000	3,226,700,000
Maximum exposure to loss	2,799,100,000	3,022,700,000
Available-for-sale | Commercial mortgage-backed securities	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	4,026,400,000	3,897,400,000
Maximum exposure to loss	4,078,000,000	4,094,800,000
Available-for-sale | Collateralized debt obligations	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	363,400,000	379,200,000
Maximum exposure to loss	391,900,000	428,800,000
Available-for-sale | Other debt obligations	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	4,167,800,000	3,779,200,000
Maximum exposure to loss	4,157,500,000	3,756,900,000
Trading | Residential mortgage-backed pass-through securities	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	47,500,000	77,700,000
Maximum exposure to loss	47,500,000	77,700,000
Trading | Commercial mortgage-backed securities	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	1,800,000	2,800,000
Maximum exposure to loss	1,800,000	2,800,000
Trading | Collateralized debt obligations	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	59,600,000	56,400,000
Maximum exposure to loss	59,600,000	56,400,000
Trading | Other debt obligations	'	'
Unconsolidated Variable Interest Entity disclosures	'	'
Asset carrying value	1,200,000	3,200,000
Maximum exposure to loss	$1,200,000	$3,200,000

Investments_Details

Investments (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fixed maturities	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	$47,001.30	$47,715.30
Gross unrealized gains	2,562.40	4,095.10
Gross unrealized losses	806.6	871.1
Fair value	48,757.10	50,939.30
Other-than-temporary impairments in AOCI	277.5	302
Net unrealized gains (losses) on impaired fixed maturities, available-for-sale related to changes in fair value subsequent to the impairment date	148.6	95
U.S. government and agencies	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	818.2	911.4
Gross unrealized gains	12.7	33.2
Gross unrealized losses	50.4	0.3
Fair value	780.5	944.3
Non-U.S. governments	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	853.2	944.9
Gross unrealized gains	148.8	264.3
Gross unrealized losses	5.2	0.9
Fair value	996.8	1,208.30
States and political subdivisions	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	3,622.80	2,940.40
Gross unrealized gains	120.9	241.1
Gross unrealized losses	85.7	2.7
Fair value	3,658	3,178.80
Corporate debt securities	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	30,280.60	31,615.40
Gross unrealized gains	1,958.80	3,029.90
Gross unrealized losses	320.4	319.9
Fair value	31,919	34,325.40
Other-than-temporary impairments in AOCI	17.1	19.5
Residential mortgage-backed pass-through securities	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	2,799.10	3,022.70
Gross unrealized gains	92.8	204.4
Gross unrealized losses	46.7	0.4
Fair value	2,845.20	3,226.70
Commercial mortgage-backed securities	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	4,078	4,094.80
Gross unrealized gains	170.6	241.7
Gross unrealized losses	222.2	439.1
Fair value	4,026.40	3,897.40
Other-than-temporary impairments in AOCI	183.4	195.4
Collateralized debt obligations	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	391.9	428.8
Gross unrealized gains	6	7
Gross unrealized losses	34.5	56.6
Fair value	363.4	379.2
Other-than-temporary impairments in AOCI	0.7	4.3
Other debt obligations	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	4,157.50	3,756.90
Gross unrealized gains	51.8	73.5
Gross unrealized losses	41.5	51.2
Fair value	4,167.80	3,779.20
Other-than-temporary impairments in AOCI	76.3	82.8
Equity securities	'	'
Available-for-sale securities disclosures	'	'
Amortized cost	113.8	132.4
Gross unrealized gains	10	12.6
Gross unrealized losses	13.3	8.5
Fair value	$110.50	$136.50

Investments_Details_2

Investments (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Amortized cost of fixed maturities available-for-sale	'	'
Due in one year or less	$2,977.30	'
Due after one year through five years	12,674.40	'
Due after five years through ten years	8,669.80	'
Due after ten years	11,253.30	'
Subtotal	35,574.80	'
Mortgage-backed and other asset-backed securities	11,426.50	'
Total	47,001.30	'
Fair value of fixed maturities available-for-sale	'	'
Due in one year or less	3,019	'
Due after one year through five years	13,297.30	'
Due after five years through ten years	9,091.20	'
Due after ten years	11,946.80	'
Subtotal	37,354.30	'
Mortgage-backed and other asset-backed securities	11,402.80	'
Total	$48,757.10	$50,939.30

Investments_Details_3

Investments (Details 3) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	$3,214.60	$3,336.10	$3,458.30
Investment expenses	'	'	'	'	-76.2	-81.2	-83
Net investment income (loss)	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30
Mortgage loans	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	611.5	635.8	649.2
Real estate	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	61.2	71.4	74.2
Policy loans	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	49.9	53.7	58.2
Cash and cash equivalents	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	14	9.6	8.5
Derivatives	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	-115.2	-131.2	-196.1
Other investment types	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	222	196.6	188.5
Available-for-sale | Fixed maturities	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	2,321.30	2,454.80	2,596.20
Available-for-sale | Equity securities	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	7.6	8.6	10.5
Trading | Fixed maturities	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	22.5	30.2	64.7
Trading | Equity securities	'	'	'	'	'	'	'
Major categories of net investment income	'	'	'	'	'	'	'
Gross investment income (loss)	'	'	'	'	$19.80	$6.60	$4.40

Investments_Details_4

Investments (Details 4) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fixed maturities, available-for-sale:	'	'	'	'	'	'	'
Gross gains	'	'	'	'	$45.50	$31	$26.40
Gross losses	'	'	'	'	-122.1	-144.9	-158.8
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	-13.9	9.2	17.1	4.9	-24.5	17.3	-49.7
Hedging, net	'	'	'	'	-115.5	-27.5	130.5
Fixed maturities, trading	'	'	'	'	-7.1	2.2	-6.7
Equity securities, available-for-sale:	'	'	'	'	'	'	'
Gross gains	'	'	'	'	0.8	0.6	2.2
Gross losses	'	'	'	'	-0.3	-0.9	-6.4
Equity securities, trading	'	'	'	'	26.9	34.1	20.3
Mortgage loans	'	'	'	'	-15.8	-51.3	-42.1
Derivatives	'	'	'	'	-23	-10.9	-180.5
Other	'	'	'	'	9.9	264.4	142.5
Net realized capital gains (losses)	32.9	87.7	0.2	-6.7	-225.2	114.1	-122.3
Proceeds from sales of investments	'	'	'	'	'	'	'
Proceeds from sales of investments in fixed maturities, available-for-sale	'	'	'	'	$1,773	$1,228.60	$881.70

Investments_Details_5

Investments (Details 5) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other-than-temporary impairment losses, net of recoveries	'	'	'	'	'	'	'
Total other-than-temporary impairment losses on available-for-sale securities	($9.50)	($43.60)	($49.10)	($33.70)	($91.50)	($135.90)	($147.60)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	-13.9	9.2	17.1	4.9	-24.5	17.3	-49.7
Net impairment losses on available-for-sale securities	-23.4	-34.4	-32	-28.8	-116	-118.6	-197.3
Fixed maturities	'	'	'	'	'	'	'
Other-than-temporary impairment losses, net of recoveries	'	'	'	'	'	'	'
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	-91.2	-135.5	-143.8
Equity securities	'	'	'	'	'	'	'
Other-than-temporary impairment losses, net of recoveries	'	'	'	'	'	'	'
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	($0.30)	($0.40)	($3.80)

Investments_Details_6

Investments (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other-Than-Temporary Impairment Credit Losses Recognized in Net Income - Rollforward	'	'	'
Beginning balance	($335.20)	($434.80)	($325.70)
Credit losses for which an other-than-temporary impairment was not previously recognized	-15.1	-20.7	-37.8
Credit losses for which an other-than-temporary impairment was previously recognized	-75.9	-80	-135.6
Reduction for credit losses previously recognized on fixed maturities now sold, paid down or intended to be sold	177.6	191.9	68.2
Net reduction (increase) for positive changes in cash flows expected to be collected and amortization	12.6	8.4	-3.9
Ending balance	($236)	($335.20)	($434.80)

Investments_Details_7

Investments (Details 7) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fixed maturities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	$9,313.20	$1,676.90
Less than twelve months, Gross unrealized losses	356.4	19.8
Greater than or equal to twelve months, Fair value	2,256	3,320
Greater than or equal to twelve months, Gross unrealized losses	450.2	851.3
Total, Fair value	11,569.20	4,996.90
Total, Gross unrealized losses	806.6	871.1
U.S. government and agencies	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	526.8	115.4
Less than twelve months, Gross unrealized losses	49.6	0.3
Greater than or equal to twelve months, Fair value	9.2	'
Greater than or equal to twelve months, Gross unrealized losses	0.8	'
Total, Fair value	536	115.4
Total, Gross unrealized losses	50.4	0.3
Non-U.S. governments	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	78.1	17.3
Less than twelve months, Gross unrealized losses	5.1	0.2
Greater than or equal to twelve months, Fair value	5.8	13.4
Greater than or equal to twelve months, Gross unrealized losses	0.1	0.7
Total, Fair value	83.9	30.7
Total, Gross unrealized losses	5.2	0.9
States and political subdivisions	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	1,338.60	235.3
Less than twelve months, Gross unrealized losses	75.3	2.1
Greater than or equal to twelve months, Fair value	46.1	8.8
Greater than or equal to twelve months, Gross unrealized losses	10.4	0.6
Total, Fair value	1,384.70	244.1
Total, Gross unrealized losses	85.7	2.7
Corporate debt securities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	4,087.90	831.8
Less than twelve months, Gross unrealized losses	155.4	10.6
Greater than or equal to twelve months, Fair value	1,278.10	1,961.70
Greater than or equal to twelve months, Gross unrealized losses	165	309.3
Total, Fair value	5,366	2,793.50
Total, Gross unrealized losses	320.4	319.9
Residential mortgage-backed pass-through securities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	1,150.30	70.4
Less than twelve months, Gross unrealized losses	38.2	0.3
Greater than or equal to twelve months, Fair value	85.9	2.4
Greater than or equal to twelve months, Gross unrealized losses	8.5	0.1
Total, Fair value	1,236.20	72.8
Total, Gross unrealized losses	46.7	0.4
Commercial mortgage-backed securities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	683.7	98.9
Less than twelve months, Gross unrealized losses	15.3	3.3
Greater than or equal to twelve months, Fair value	495.6	785
Greater than or equal to twelve months, Gross unrealized losses	206.9	435.8
Total, Fair value	1,179.30	883.9
Total, Gross unrealized losses	222.2	439.1
Collateralized debt obligations	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	88.8	72.2
Less than twelve months, Gross unrealized losses	1.4	1
Greater than or equal to twelve months, Fair value	47.4	133.8
Greater than or equal to twelve months, Gross unrealized losses	33.1	55.6
Total, Fair value	136.2	206
Total, Gross unrealized losses	34.5	56.6
Other debt obligations	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	1,359	235.6
Less than twelve months, Gross unrealized losses	16.1	2
Greater than or equal to twelve months, Fair value	287.9	414.9
Greater than or equal to twelve months, Gross unrealized losses	25.4	49.2
Total, Fair value	1,646.90	650.5
Total, Gross unrealized losses	41.5	51.2
Equity securities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	16.7	5.8
Less than twelve months, Gross unrealized losses	0.3	0.1
Greater than or equal to twelve months, Fair value	48.3	52.9
Greater than or equal to twelve months, Gross unrealized losses	13	8.4
Total, Fair value	65	58.7
Total, Gross unrealized losses	13.3	8.5
Principal Life Insurance Company | Fixed maturities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Less than twelve months, Fair value	8,899.50	1,382.10
Less than twelve months, Gross unrealized losses	339.8	16.2
Greater than or equal to twelve months, Fair value	2,005.90	3,037.30
Greater than or equal to twelve months, Gross unrealized losses	412.7	809.5
Total, Fair value	10,905.40	4,419.40
Total, Gross unrealized losses	752.5	825.7
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure	'	'
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less Than Twelve Months	1,154	224
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Twelve Months or Longer	359	488
Available-for-sale Securities in Unrealized Loss Position, Aggregate Losses On Investment Grade Investments, Less Than Twelve Months	325.9	13.3
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Percent Investment Grade (as a percent)	87.00%	71.00%
Available-for-sale Securities in Unrealized Loss Positions, Qualitative Disclosure, Average Price (percent of carrying value to amortized cost)	94	84
Available-for-sale Securities in Unrealized Loss Positions, Percent Investment Grade, Less Than Twelve Months (as a percent)	94.00%	89.00%
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Less Than Twelve Months (percent of carrying value to amortized cost)	96	99
Available-for-sale Securities in Unrealized Loss Positions, Average Price, Twelve Months or Longer (percent of carrying value to amortized cost)	83	79
Principal Life Insurance Company | Corporate debt securities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Greater than or equal to twelve months, Gross unrealized losses	127.6	268.1
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)	89	86
Principal Life Insurance Company | Commercial mortgage-backed securities	'	'
Gross Unrealized Losses for Fixed Maturities and Equity Securities	'	'
Greater than or equal to twelve months, Gross unrealized losses	$206.90	$435.80
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)	71	64

Investments_Details_8

Investments (Details 8) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Net Unrealized Gains and Losses on Available-for-Sale Securities and Derivative Instruments	'	'
Net unrealized gains (losses) on fixed maturities, available-for-sale	$2,064	$3,562.50
Noncredit component of impairment losses on fixed maturities, available-for-sale	-277.5	-302
Net unrealized gains (losses) on equity securities, available-for-sale	-3.3	4.1
Adjustments for assumed changes in amortization patterns	-265.9	-515.2
Adjustments for assumed changes in policyholder liabilities	-602.5	-1,198.70
Net unrealized gains (losses) on derivative instruments	56	90.7
Net unrealized gains (losses) on equity method subsidiaries and noncontrolling interest adjustments	71.8	191.3
Provision for deferred income tax benefits (taxes)	-342	-597
Net unrealized gains (losses) on available-for-sale securities and derivative instruments	$700.60	$1,235.70

Investments_Details_9

Investments (Details 9) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	$11,603.40	$11,617.10	$10,829.30	'
Mortgage loan valuation allowance	-69.8	-97.4	-102.1	-121.1
Mortgage loans, Total carrying value	11,533.60	11,519.70	'	'
Commercial mortgage loans	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	10,327.70	10,235.10	9,461.40	'
Mortgage loan valuation allowance	-28.7	-51.8	-64.8	-80.6
Mortgage loans, purchased	166.1	149.1	50.3	'
Mortgage loans, sold	13	31.1	0	'
Percent of mortgage loans (as a percent)	100.00%	100.00%	'	'
Commercial mortgage loans | Office	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	3,360.50	3,078.80	'	'
Percent of mortgage loans (as a percent)	32.60%	30.10%	'	'
Commercial mortgage loans | Retail	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	2,668.50	2,928.30	'	'
Percent of mortgage loans (as a percent)	25.80%	28.60%	'	'
Commercial mortgage loans | Industrial	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	1,766.20	1,765.50	'	'
Percent of mortgage loans (as a percent)	17.10%	17.20%	'	'
Commercial mortgage loans | Apartments	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	1,911.20	1,685.90	'	'
Percent of mortgage loans (as a percent)	18.50%	16.50%	'	'
Commercial mortgage loans | Hotel	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	333.1	445.8	'	'
Percent of mortgage loans (as a percent)	3.20%	4.40%	'	'
Commercial mortgage loans | Mixed use/other	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	288.2	330.8	'	'
Percent of mortgage loans (as a percent)	2.80%	3.20%	'	'
Commercial mortgage loans | New England	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	528.5	536.6	'	'
Percent of mortgage loans (as a percent)	5.10%	5.20%	'	'
Commercial mortgage loans | Middle Atlantic	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	2,489	2,233.40	'	'
Percent of mortgage loans (as a percent)	24.10%	21.80%	'	'
Commercial mortgage loans | East North Central	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	519.9	635.6	'	'
Percent of mortgage loans (as a percent)	5.00%	6.20%	'	'
Commercial mortgage loans | West North Central	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	302.9	377.3	'	'
Percent of mortgage loans (as a percent)	2.90%	3.70%	'	'
Commercial mortgage loans | South Atlantic	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	1,949.50	2,135	'	'
Percent of mortgage loans (as a percent)	18.90%	20.90%	'	'
Commercial mortgage loans | East South Central	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	192.8	244.8	'	'
Percent of mortgage loans (as a percent)	1.90%	2.40%	'	'
Commercial mortgage loans | West South Central	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	830.3	767.9	'	'
Percent of mortgage loans (as a percent)	8.00%	7.50%	'	'
Commercial mortgage loans | Mountain	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	747.1	726.6	'	'
Percent of mortgage loans (as a percent)	7.20%	7.10%	'	'
Commercial mortgage loans | Pacific	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	2,722.50	2,562.30	'	'
Percent of mortgage loans (as a percent)	26.50%	25.00%	'	'
Commercial mortgage loans | International	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	45.2	15.6	'	'
Percent of mortgage loans (as a percent)	0.40%	0.20%	'	'
Residential mortgage loans	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	1,275.70	1,382	1,367.90	'
Mortgage loan valuation allowance	-41.1	-45.6	-37.3	-40.5
Mortgage loans, purchased	157.2	153	40.6	'
Mortgage loans, sold	0	14.2	18.4	'
Home equity	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	394.9	495.7	'	'
First liens	'	'	'	'
Mortgage loan disclosures	'	'	'	'
Mortgage loans, Total amortized cost	$880.80	$886.30	'	'

Investments_Details_10

Investments (Details 10) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

In Millions, unless otherwise specified

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Commercial mortgage loans

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Brick and mortar

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Credit tenant loans

Residential mortgage loans

Residential mortgage loans

Residential mortgage loans

Residential mortgage loans

Residential mortgage loans

Residential mortgage loans

Residential mortgage loans

Home equity

Home equity

Home equity

Home equity

Home equity

Home equity

First liens

First liens

First liens

First liens

First liens

First liens

A- and above

A- and above

BBB+ thru BBB-

BBB+ thru BBB-

BB+ thru BB-

BB+ thru BB-

B+ and below

B+ and below

A- and above

A- and above

BBB+ thru BBB-

BBB+ thru BBB-

BB+ thru BB-

BB+ thru BB-

B+ and below

B+ and below

A- and above

A- and above

BBB+ thru BBB-

BBB+ thru BBB-

BB+ thru BB-

BB+ thru BB-

B+ and below

B+ and below

Performing

Performing

Nonperforming

Nonperforming

Performing

Performing

Nonperforming

Nonperforming

Performing

Performing

Nonperforming

Nonperforming

Mortgage loan credit quality disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

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'

Mortgage loans, Total amortized cost

$11,603.40

$11,617.10

$10,829.30

$10,327.70

$10,235.10

$9,461.40

$8,286.40

$7,489

$1,713.70

$2,099.40

$155.50

$268.40

$172.10

$378.30

$9,881.10

$9,705

$8,091.90

$7,257.70

$1,463.70

$1,804.50

$155.40

$266.80

$170.10

$376

$446.60

$530.10

$194.50

$231.30

$250

$294.90

$0.10

$1.60

$2

$2.30

$1,275.70

$1,382

$1,367.90

$1,240.40

$1,337.60

$35.30

$44.40

$394.90

$495.70

$378.30

$472.60

$16.60

$23.10

$880.80

$886.30

$862.10

$865

$18.70

$21.30

Mortgage loans, Days delinquent to be considered nonperforming

'

'

'

'

'

'

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'90 days

'90 days

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Investments_Details_11

Investments (Details 11) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Mortgage loan non-accrual and aging disclosures	'	'	'
Mortgage loans, Non-accrual status	$61.20	$80.80	'
30-59 days past due	36.8	60.8	'
60-89 days past due	8.4	21.6	'
90 days or more past due	36.8	23.7	'
Total past due	82	106.1	'
Current	11,521.40	11,511	'
Mortgage loans, Total amortized cost	11,603.40	11,617.10	10,829.30
Recorded investment 90 days or more past due and accruing	7.3	8.1	'
Commercial mortgage loans	'	'	'
Mortgage loan non-accrual and aging disclosures	'	'	'
Mortgage loans, Total amortized cost	10,327.70	10,235.10	9,461.40
Brick and mortar	'	'	'
Mortgage loan non-accrual and aging disclosures	'	'	'
Mortgage loans, Non-accrual status	33.2	44.5	'
30-59 days past due	'	32.8	'
60-89 days past due	'	13.7	'
90 days or more past due	16.7	'	'
Total past due	16.7	46.5	'
Current	9,864.40	9,658.50	'
Mortgage loans, Total amortized cost	9,881.10	9,705	'
Credit tenant loans	'	'	'
Mortgage loan non-accrual and aging disclosures	'	'	'
Current	446.6	530.1	'
Mortgage loans, Total amortized cost	446.6	530.1	'
Residential mortgage loans	'	'	'
Mortgage loan non-accrual and aging disclosures	'	'	'
Mortgage loans, Total amortized cost	1,275.70	1,382	1,367.90
Home equity	'	'	'
Mortgage loan non-accrual and aging disclosures	'	'	'
Mortgage loans, Non-accrual status	16.6	23.1	'
30-59 days past due	4.4	5.7	'
60-89 days past due	1	2.8	'
90 days or more past due	3	3.9	'
Total past due	8.4	12.4	'
Current	386.5	483.3	'
Mortgage loans, Total amortized cost	394.9	495.7	'
First liens	'	'	'
Mortgage loan non-accrual and aging disclosures	'	'	'
Mortgage loans, Non-accrual status	11.4	13.2	'
30-59 days past due	32.4	22.3	'
60-89 days past due	7.4	5.1	'
90 days or more past due	17.1	19.8	'
Total past due	56.9	47.2	'
Current	823.9	839.1	'
Mortgage loans, Total amortized cost	880.8	886.3	'
Recorded investment 90 days or more past due and accruing	$7.30	$8.10	'

Investments_Details_12

Investments (Details 12) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in mortgage loan valuation allowance	'	'	'
Beginning balance, Mortgage loan valuation allowance	$97.40	$102.10	$121.10
Provision: Mortgage loan valuation allowance	14.9	53.2	44.2
Charge-offs: Mortgage loan valuation allowance	-46.3	-61.8	-66.3
Recoveries: Mortgage loan valuation allowance	3.9	3.8	3.3
Effect of exchange rates: Mortgage loan valuation allowance	-0.1	0.1	-0.2
Ending balance, Mortgage loan valuation allowance	69.8	97.4	102.1
Individually evaluated for impairment, Mortgage loan valuation allowance	12.6	12.8	19.5
Collectively evaluated for impairment, Mortgage loan valuation allowance	57.2	84.6	82.6
Individually evaluated for impairment, Mortgage loans	37.4	53.3	141.4
Collectively evaluated for impairment, Mortgage loans	11,566	11,563.80	10,687.90
Mortgage loans, Total amortized cost	11,603.40	11,617.10	10,829.30
Commercial mortgage loans	'	'	'
Mortgage loan valuation allowance disclosures	'	'	'
Mortgage loans, Days delinquent to be analyzed for valuation allowance	'60 days	'	'
Changes in mortgage loan valuation allowance	'	'	'
Beginning balance, Mortgage loan valuation allowance	51.8	64.8	80.6
Provision: Mortgage loan valuation allowance	4.1	13.5	17
Charge-offs: Mortgage loan valuation allowance	-28	-26.7	-32.9
Recoveries: Mortgage loan valuation allowance	0.8	0.2	0.1
Ending balance, Mortgage loan valuation allowance	28.7	51.8	64.8
Individually evaluated for impairment, Mortgage loan valuation allowance	2.4	2.4	16.3
Collectively evaluated for impairment, Mortgage loan valuation allowance	26.3	49.4	48.5
Individually evaluated for impairment, Mortgage loans	4.4	13.6	114
Collectively evaluated for impairment, Mortgage loans	10,323.30	10,221.50	9,347.40
Mortgage loans, Total amortized cost	10,327.70	10,235.10	9,461.40
Residential mortgage loans	'	'	'
Changes in mortgage loan valuation allowance	'	'	'
Beginning balance, Mortgage loan valuation allowance	45.6	37.3	40.5
Provision: Mortgage loan valuation allowance	10.8	39.7	27.2
Charge-offs: Mortgage loan valuation allowance	-18.3	-35.1	-33.4
Recoveries: Mortgage loan valuation allowance	3.1	3.6	3.2
Effect of exchange rates: Mortgage loan valuation allowance	-0.1	0.1	-0.2
Ending balance, Mortgage loan valuation allowance	41.1	45.6	37.3
Individually evaluated for impairment, Mortgage loan valuation allowance	10.2	10.4	3.2
Collectively evaluated for impairment, Mortgage loan valuation allowance	30.9	35.2	34.1
Individually evaluated for impairment, Mortgage loans	33	39.7	27.4
Collectively evaluated for impairment, Mortgage loans	1,242.70	1,342.30	1,340.50
Mortgage loans, Total amortized cost	$1,275.70	$1,382	$1,367.90

Investments_Details_13

Investments (Details 13) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commercial mortgage loans	'	'	'
Impaired mortgage loans	'	'	'
Recorded investment in impaired mortgage loans	$25.90	$27.30	'
Unpaid principal balance of impaired mortgage loans	37.1	29.7	'
Related allowance for impaired mortgage loans	2.4	2.4	'
Average investment in impaired mortgage loans	26.6	70.6	90.3
Interest income recognized on impaired mortgage loans	0.5	2.8	1.9
Brick and mortar	'	'	'
Impaired mortgage loans	'	'	'
Recorded investment in impaired mortgage loans with no related allowance	21.5	22.9	'
Recorded investment in impaired mortgage loans with related allowance	4.4	4.4	'
Unpaid principal balance of impaired mortgage loans with no related allowance	32.7	25.3	'
Unpaid principal balance of impaired mortgage loans with related allowance	4.4	4.4	'
Related allowance for impaired mortgage loans	2.4	2.4	'
Average investment in impaired mortgage loans with no related allowance	22.2	11.4	11.3
Average investment in impaired mortgage loans with related allowance	4.4	59.2	79
Interest income recognized on impaired mortgage loans with no related allowance	0.2	2.6	0.9
Interest income recognized on impaired mortgage loans with related allowance	0.3	0.2	1
Residential mortgage loans	'	'	'
Impaired mortgage loans	'	'	'
Recorded investment in impaired mortgage loans	33	39.7	'
Unpaid principal balance of impaired mortgage loans	32.1	36.4	'
Related allowance for impaired mortgage loans	10.2	10.4	'
Average investment in impaired mortgage loans	36.3	33.7	26.6
Interest income recognized on impaired mortgage loans	1.3	1	1
Home equity	'	'	'
Impaired mortgage loans	'	'	'
Recorded investment in impaired mortgage loans with related allowance	19.5	20.8	'
Unpaid principal balance of impaired mortgage loans with related allowance	19.7	20.7	'
Related allowance for impaired mortgage loans	9.2	9.1	'
Average investment in impaired mortgage loans with related allowance	20.2	17.7	12.6
Interest income recognized on impaired mortgage loans with related allowance	1.1	0.9	0.8
First liens	'	'	'
Impaired mortgage loans	'	'	'
Recorded investment in impaired mortgage loans with no related allowance	4.6	9.7	'
Recorded investment in impaired mortgage loans with related allowance	8.9	9.2	'
Unpaid principal balance of impaired mortgage loans with no related allowance	4.6	6.6	'
Unpaid principal balance of impaired mortgage loans with related allowance	7.8	9.1	'
Related allowance for impaired mortgage loans	1	1.3	'
Average investment in impaired mortgage loans with no related allowance	7.2	7	4.4
Average investment in impaired mortgage loans with related allowance	8.9	9	9.6
Interest income recognized on impaired mortgage loans with related allowance	$0.20	$0.10	$0.20

Investments_Details_14

Investments (Details 14) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	item	item	item
Mortgage Loan Modifications	'	'	'
Number of mortgage loans modified as a troubled debt restructuring	74	338	159
Recorded investment of mortgage loans modified as a troubled debt restructuring	$5.30	$35.10	$13.90
Number of mortgage loans modified as a troubled debt restructuring in payment default	20	13	8
Recorded investment of mortgage loans modified as a troubled debt restructuring in payment default	0.3	13.7	4.7
Brick and mortar	'	'	'
Mortgage Loan Modifications	'	'	'
Number of mortgage loans modified as a troubled debt restructuring	2	2	1
Recorded investment of mortgage loans modified as a troubled debt restructuring	0.9	18	4.4
Number of mortgage loans modified as a troubled debt restructuring in payment default	'	1	1
Recorded investment of mortgage loans modified as a troubled debt restructuring in payment default	'	13.7	4.4
Home equity	'	'	'
Mortgage Loan Modifications	'	'	'
Number of mortgage loans modified as a troubled debt restructuring	69	324	151
Recorded investment of mortgage loans modified as a troubled debt restructuring	3.8	15	7.9
Number of mortgage loans modified as a troubled debt restructuring in payment default	19	12	6
First liens	'	'	'
Mortgage Loan Modifications	'	'	'
Number of mortgage loans modified as a troubled debt restructuring	3	12	7
Recorded investment of mortgage loans modified as a troubled debt restructuring	0.6	2.1	1.6
Number of mortgage loans modified as a troubled debt restructuring in payment default	1	'	1
Recorded investment of mortgage loans modified as a troubled debt restructuring in payment default	$0.30	'	$0.30

Investments_Details_15

Investments (Details 15) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real estate	'	'	'
Depreciation expense on invested real estate	$44.40	$45.10	$41.40
Accumulated depreciation on invested real estate	364.9	332.8	'
Summarized financial information of unconsolidated entities	'	'	'
Total assets, unconsolidated entities	47,401.90	46,036.20	'
Total liabilities, unconsolidated entities	39,588	38,080.90	'
Total equity, unconsolidated entities	7,813.90	7,955.30	'
Net investment in unconsolidated entities	1,098.60	1,100.60	'
Total revenues, unconsolidated entities	3,002.90	4,555.90	5,574.60
Total expenses, unconsolidated entities	2,253.20	3,774.50	4,849.80
Net income, unconsolidated entities	738.6	750.1	719.3
Our share of net income of unconsolidated entities	133.4	120.1	116.5
Other Types of Investments	'	'	'
Direct financing leases	720.2	655.1	'
Securities Posted as Collateral	'	'	'
Fixed maturity securities posted as collateral for a reinsurance arrangement, derivative credit support annex (collateral) agreements, Futures Commission Merchant agreements and an obligation under funding agreements with the Federal Home Loan Bank of Des Moines	1,057.40	'	'
Commercial mortgage loans and home equity mortgages posted as collateral associated with obligation under funding agreements with the Federal Home Loan Bank of Des Moines	$2,435.40	'	'

Investments_Details_16

Investments (Details 16) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Financial Asset Offsetting	'	'
Gross amount of recognized assets subject to netting agreements	$716.70	$1,164.50
Amount of liabilities that offset the gross amount of assets subject to netting agreements not offset in statement of financial position	-581.5	-779.3
Collateral received, financial assets	-133.9	-373.7
Net amount of assets subject to netting agreements	1.3	11.5
Derivative assets	'	'
Financial Asset Offsetting	'	'
Gross amount of recognized assets subject to netting agreements	664.9	1,016.30
Amount of liabilities that offset the gross amount of assets subject to netting agreements not offset in statement of financial position	-581.5	-779.3
Collateral received, financial assets	-82.1	-225.5
Net amount of assets subject to netting agreements	1.3	11.5
Gross amount of assets not subject to netting agreements	0.2	0.4
Reverse repurchase agreements	'	'
Financial Asset Offsetting	'	'
Gross amount of recognized assets subject to netting agreements	51.8	148.2
Collateral received, financial assets	($51.80)	($148.20)

Investments_Details_17

Investments (Details 17) (Derivative liabilities, USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Derivative liabilities	'	'
Financial Liability Offsetting	'	'
Gross amount of recognized liabilities subject to netting agreements	$1,022	$1,198.20
Amount of assets that offset the gross amount of liabilities subject to netting agreements not offset in statement of financial position	-581.5	-779.3
Collateral pledged, financial liabilities	-362.1	-279.1
Net amount of liabilities subject to netting agreements	78.4	139.8
Gross amount of liabilities not subject to netting agreements	$226.70	$329.80

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative Financial Instruments, exposure	'	'
GMWB minimum account balance to make withdrawals by customer	$0	'
Cash and securities posted under collateral arrangements associated with derivative credit support agreements and Futures Commission Merchant agreements	393.1	296.9
Aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position	1,042.90	1,205.40
Collateral and initial margin posted supporting derivatives with credit-risk-related contingent features that were in a liability position	393.1	296.9
Additional collateral required to be posted if derivative credit-risk-related contingent features were triggered	75.9	'
Cash collateral received associated with derivative credit support annex agreements and Futures Commission Merchant agreements	32.5	207.8
Notional amount	38,840.30	34,256.40
Gross credit exposure	720.1	1,086.70
Less: collateral received	115.9	248
Net credit exposure	604.2	838.7
Interest rate swaps	'	'
Derivative Financial Instruments, exposure	'	'
Cash exchanged under contract	0	'
Principal payments made under contract	0	'
Notional amount	20,570.80	18,381.20
Gross credit exposure	435.5	683.9
Interest rate options	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	4,100	500
Gross credit exposure	42.5	48.5
Swaptions	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	325	325
Gross credit exposure	1	0.7
Interest rate futures	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	92.5	82
Currency swaps	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	2,367.50	3,454.10
Gross credit exposure	200.9	263.8
Currency forwards	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	247.4	557.2
Gross credit exposure	0.6	6.8
Currency options	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	'	1,400
Gross credit exposure	'	1.9
Equity options	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	2,010.40	1,811.80
Gross credit exposure	30	74.3
Equity futures	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	273.3	373.6
Credit default swaps	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	1,153.20	1,378.30
Gross credit exposure	9.5	6.8
Total return swaps	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	90	100
Gross credit exposure	0.1	'
Futures	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	9.1	'
Embedded derivative financial instruments	'	'
Derivative Financial Instruments, exposure	'	'
Notional amount	$7,601.10	$5,893.20

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	$665.10	$1,016.70
Total derivative instruments, liabilities	1,248.70	1,528
Fair value of embedded derivative liabilities reported with contractholder funds	6.9	170.5
Derivatives designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	121.7	200.3
Total derivative instruments, liabilities	336.6	567.7
Derivatives not designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	543.4	816.4
Total derivative instruments, liabilities	912.1	960.3
Interest rate contracts | Derivatives designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	0.1	10.3
Total derivative instruments, liabilities	285.4	440.5
Interest rate contracts | Derivatives not designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	452.2	677.1
Total derivative instruments, liabilities	489.6	493.9
Foreign exchange contracts | Derivatives designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	121.6	190
Total derivative instruments, liabilities	51.2	127.2
Foreign exchange contracts | Derivatives not designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	51.6	58.2
Total derivative instruments, liabilities	17.9	14.3
Equity contracts | Derivatives not designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	30	74.3
Total derivative instruments, liabilities	145	27.7
Credit contracts | Derivatives not designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, assets	9.6	6.8
Total derivative instruments, liabilities	35.5	96.6
Other contracts | Derivatives not designated as hedging instrument	'	'
Derivatives, fair value disclosures	'	'
Total derivative instruments, liabilities	$224.10	$327.80

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Credit derivatives sold disclosures	'	'
Reduction in total maximum future payments due to purchased credit protection	$44.90	$15
Net asset (liability) fair value of purchased credit derivative transactions	-0.5	0.2
Notional amount	818.9	1,018.50
Fair value	-19.2	-88.5
Maximum future payments	818.9	1,018.50
Weighted average expected life	'3 years 10 months 24 days	'2 years 10 months 24 days
Single name credit default swaps	'	'
Credit derivatives sold disclosures	'	'
Notional amount	653.5	853.1
Fair value	5.1	-10.4
Maximum future payments	653.5	853.1
Weighted average expected life	'4 years	'2 years 7 months 6 days
Single name credit default swaps | Corporate debt securities | AAA	'	'
Credit derivatives sold disclosures	'	'
Notional amount	10	'
Fair value	0.3	'
Maximum future payments	10	'
Weighted average expected life	'4 years 8 months 12 days	'
Single name credit default swaps | Corporate debt securities | AA	'	'
Credit derivatives sold disclosures	'	'
Notional amount	84	70
Fair value	1.8	-0.2
Maximum future payments	84	70
Weighted average expected life	'4 years	'2 years 6 months
Single name credit default swaps | Corporate debt securities | A	'	'
Credit derivatives sold disclosures	'	'
Notional amount	294.5	572
Fair value	4.2	2.4
Maximum future payments	294.5	572
Weighted average expected life	'4 years	'2 years 4 months 24 days
Single name credit default swaps | Corporate debt securities | BBB	'	'
Credit derivatives sold disclosures	'	'
Notional amount	265	200
Fair value	-1.2	-1.6
Maximum future payments	265	200
Weighted average expected life	'3 years 10 months 24 days	'3 years
Single name credit default swaps | Structured finance | Near default	'	'
Credit derivatives sold disclosures	'	'
Notional amount	'	11.1
Fair value	'	-11
Maximum future payments	'	11.1
Weighted average expected life	'	'8 years 6 months
Basket and index credit default swaps	'	'
Credit derivatives sold disclosures	'	'
Notional amount	165.4	165.4
Fair value	-24.3	-78.1
Maximum future payments	165.4	165.4
Weighted average expected life	'3 years 4 months 24 days	'4 years 4 months 24 days
Basket and index credit default swaps | Corporate debt securities | Near default	'	'
Credit derivatives sold disclosures	'	'
Notional amount	110.4	110.4
Fair value	-19.9	-65.2
Maximum future payments	110.4	110.4
Weighted average expected life	'3 years 2 months 12 days	'4 years 2 months 12 days
Notional amount of derivative whose credit risk is borne by third party investors	88	88
Basket and index credit default swaps | Government/municipalities | AA	'	'
Credit derivatives sold disclosures	'	'
Notional amount	30	30
Fair value	-3.5	-7.3
Maximum future payments	30	30
Weighted average expected life	'3 years 8 months 12 days	'4 years 8 months 12 days
Basket and index credit default swaps | Structured finance | BBB	'	'
Credit derivatives sold disclosures	'	'
Notional amount	25	25
Fair value	-0.9	-5.6
Maximum future payments	$25	$25
Weighted average expected life	'3 years 6 months	'4 years 6 months

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative Financial Instruments	'	'
Future potential payments in the event of default of an investment in fixed maturity securities that contain embedded credit derivatives	$0	'
Hybrid instruments disclosures	'	'
Amortized cost	74.6	111.4
Carrying value	73.2	109.2
Weighted average expected life	'4 years	'3 years 9 months 18 days
Corporate debt securities	'	'
Hybrid instruments disclosures	'	'
Amortized cost	23.4	45.5
Carrying value	23.4	45.4
Weighted average expected life	'3 years	'2 years 1 month 6 days
Corporate debt securities | BBB	'	'
Hybrid instruments disclosures	'	'
Amortized cost	23.4	20.5
Carrying value	23.4	20.5
Weighted average expected life	'3 years	'4 years
Corporate debt securities | B	'	'
Hybrid instruments disclosures	'	'
Amortized cost	'	25
Carrying value	'	24.9
Weighted average expected life	'	'6 months
Structured finance	'	'
Hybrid instruments disclosures	'	'
Amortized cost	51.2	65.9
Carrying value	49.8	63.8
Weighted average expected life	'4 years 6 months	'4 years 10 months 24 days
Structured finance | A	'	'
Hybrid instruments disclosures	'	'
Amortized cost	18.1	'
Carrying value	16.7	'
Weighted average expected life	'4 years 9 months 18 days	'
Structured finance | AA	'	'
Hybrid instruments disclosures	'	'
Amortized cost	'	4.6
Carrying value	'	4.6
Weighted average expected life	'	'17 years
Structured finance | BB	'	'
Hybrid instruments disclosures	'	'
Amortized cost	5.5	39.6
Carrying value	5.5	37.5
Weighted average expected life	'3 years 3 months 18 days	'2 years 10 months 24 days
Structured finance | B	'	'
Hybrid instruments disclosures	'	'
Amortized cost	4.1	4
Carrying value	4.1	4
Weighted average expected life	'3 years 1 month 6 days	'4 years 4 months 24 days
Structured finance | CCC	'	'
Hybrid instruments disclosures	'	'
Amortized cost	23.5	17.7
Carrying value	$23.50	$17.70
Weighted average expected life	'4 years 9 months 18 days	'6 years 4 months 24 days

Derivative_Financial_Instrumen6

Derivative Financial Instruments (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in net income on derivatives	$101.90	$48.60	($135.20)
Amount of gain (loss) recognized in net income on related hedged item	-96.2	-46.3	132.2
Fair Value Hedges	'	'	'
Effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Gain (loss) on periodic settlements on interest rate and foreign exchange contracts in fair value hedge of fixed maturities, available-for-sale reported in net investment income	-120.7	-134.3	-158.9
Gain (loss) on periodic settlements on interest rate and foreign exchange contracts in fair value hedge of investment-type insurance contracts reported in benefits, claims and settlement expenses	33.2	37.1	44
Fair Value Hedges | Interest rate contracts | Fixed maturities, available-for-sale	'	'	'
Effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in net income on derivatives	139.5	38.6	-108.5
Amount of gain (loss) recognized in net income on related hedged item	-133.3	-34.1	105.4
Fair Value Hedges | Interest rate contracts | Investment-type insurance contracts	'	'	'
Effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in net income on derivatives	-0.7	'	-2.2
Amount of gain (loss) recognized in net income on related hedged item	0.2	'	2.4
Fair Value Hedges | Foreign exchange contracts | Fixed maturities, available-for-sale	'	'	'
Effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in net income on derivatives	-0.2	0.7	1.1
Amount of gain (loss) recognized in net income on related hedged item	0.4	0.4	-1.3
Fair Value Hedges | Foreign exchange contracts | Investment-type insurance contracts	'	'	'
Effect of derivatives in fair value hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in net income on derivatives	-36.7	9.3	-25.6
Amount of gain (loss) recognized in net income on related hedged item	$36.50	($12.60)	$25.70

Derivative_Financial_Instrumen7

Derivative Financial Instruments (Details 6) (Cash Flow Hedges, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Maximum length of time hedging exposure to variability in future cash flows for forecasted transactions	'6 years 6 months	'	'
Gross unrealized gains (losses) reported in accumulated OCI related to active hedges of forecasted transactions	$61.70	'	'
Gross unrealized gains (losses) reclassified from OCI into net income due to forecasted transaction probable of not occurring	0.2	0	'
Amount of gain (loss) recognized in accumulated OCI on derivatives (effective portion)	-73.9	-1.6	148.8
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	-11.6	-3.4	-21.2
Gain (loss) on periodic settlements on interest rate and foreign exchange contracts in cash flow hedge of fixed maturities, available-for-sale reported in net investment income	7.7	8	9.3
Gain (loss) on periodic settlements on interest rate and foreign exchange contracts in cash flow hedge of investment-type insurance contracts reported in benefits, claims and settlement expenses	-11	-13.4	-13.1
Net gains (losses) expected to be reclassified from accumulated OCI into net income in the next 12 months	2.8	'	'
Interest rate contracts | Fixed maturities, available-for-sale | Net investment income	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in accumulated OCI on derivatives (effective portion)	-80.5	16.2	107.1
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	11.7	8.9	7.2
Interest rate contracts | Fixed maturities, available-for-sale | Net realized capital gains (losses)	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	'	'	-0.2
Interest rate contracts | Investment-type insurance contracts | Benefits, claims and settlement expenses	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in accumulated OCI on derivatives (effective portion)	2.5	2.5	-1
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	'	'	-0.8
Interest rate contracts | Hedged debt | Operating expense	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	-6.6	-5.9	-5.3
Foreign exchange contracts | Net realized capital gains (losses)	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Gain (loss) resulting from the ineffective portion in cash flow hedging relationships	0.8	0.5	0.5
Foreign exchange contracts | Fixed maturities, available-for-sale | Net realized capital gains (losses)	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in accumulated OCI on derivatives (effective portion)	-0.9	-27.9	29.9
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	-16.7	-6.4	-20.4
Foreign exchange contracts | Investment-type insurance contracts | Benefits, claims and settlement expenses	'	'	'
Effect of derivatives in cash flow hedging relationships and the related hedged items on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in accumulated OCI on derivatives (effective portion)	5	7.6	12.8
Amount of gain (loss) reclassified from accumulated OCI on derivatives (effective portion)	'	'	($1.70)

Derivative_Financial_Instrumen8

Derivative Financial Instruments (Details 7) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effect of derivatives not designated as hedging instruments on the consolidated statements of operations	'	'	'
Amount of gain (loss) recognized in net income on derivatives	($102.10)	$3	($95.90)
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	-137.6	-7.9	93.3
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	-0.1	63.1	-34.1
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	-159.4	-100.5	55.2
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	40.6	11	-9.9
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	$154.40	$37.30	($200.40)

Closed_Block_Details

Closed Block (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Closed Block liabilities	'	'	'	'
Closed Block liabilities: Future policy benefits and claims	$4,532	$4,664.50	'	'
Closed Block liabilities: Other policyholder funds	10.5	10.7	'	'
Closed Block liabilities: Policyholder dividends payable	270.5	280.6	'	'
Closed Block liabilities: Policyholder dividend obligation	111.6	131	'	'
Closed Block Liabilities: Deferred income taxes	2.2	'	'	'
Closed Block liabilities: Other liabilities	24.7	31.3	'	'
Total Closed Block liabilities	4,951.50	5,118.10	'	'
Assets designated to the Closed Block	'	'	'	'
Closed Block assets: Fixed maturities, available-for-sale	2,470.90	2,735.10	'	'
Closed Block assets: Fixed maturities, trading	13.4	17	'	'
Closed Block assets: Equity securities, available-for-sale	3.6	5.5	'	'
Closed Block assets: Mortgage loans	828.6	719.4	'	'
Closed Block assets: Policy loans	644.2	665.5	'	'
Closed Block assets: Other investments	118.5	158	'	'
Closed Block assets: Total investments	4,079.20	4,300.50	'	'
Closed Block assets: Cash and cash equivalents	70.3	51.3	'	'
Closed Block assets: Accrued investment income	49.5	52.5	'	'
Closed Block assets: Premiums due and other receivables	11.7	13.2	'	'
Closed Block assets: Deferred income tax asset	66.2	39.2	'	'
Closed Block assets: Other assets	2.2	'	'	'
Total assets designated to the Closed Block	4,279.10	4,456.70	'	'
Excess of Closed Block liabilities over assets designated to the Closed Block	672.4	661.4	'	'
Amounts included in accumulated other comprehensive income (loss)	12.9	62.4	'	'
Maximum future earnings to be recognized from Closed Block assets and liabilities	$685.30	$723.80	$787	$847.60

Closed_Block_Details_2

Closed Block (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'
Closed Block: Premiums and other considerations	$379.90	$397.40	$428.80
Closed Block: Net investment income (loss)	207.7	222.8	238.2
Closed Block: Net realized capital gains (losses)	-12.3	3.6	7.9
Closed Block: Total revenues	575.3	623.8	674.9
Expenses	'	'	'
Closed Block: Benefits, claims and settlement expenses	320.1	325.7	370.7
Closed Block: Dividends to policyholders	184.4	192.6	204.2
Closed Block: Operating expenses	4.7	4.9	2.9
Closed Block: Total expenses	509.2	523.2	577.8
Closed Block revenues, net of Closed Block expenses, before income taxes	66.1	100.6	97.1
Closed Block: Income taxes (benefits)	21.1	32.6	31.2
Closed Block revenues, net of Closed Block expenses and income taxes	45	68	65.9
Funding adjustment charges	-6.5	-4.8	-5.3
Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustment charges	$38.50	$63.20	$60.60

Closed_Block_Details_3

Closed Block (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in maximum future earnings of the Closed Block	'	'	'
Maximum future earnings to be recognized from Closed Block assets and liabilities, Beginning of year	$723.80	$787	$847.60
Maximum future earnings to be recognized from Closed Block assets and liabilities, End of year	685.3	723.8	787
Closed Block revenues, net of Closed Block expenses, income taxes and funding adjustment charges	($38.50)	($63.20)	($60.60)

Deferred_Acquisition_Costs_Det

Deferred Acquisition Costs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in deferred acquisition costs	'	'	'
Balance at beginning of year, deferred acquisition costs	$2,590	$2,358.10	$2,442.20
Additions to deferred acquisition costs	447	428.9	344.4
Amortization of deferred acquisition costs	-187.1	-94.9	-271.4
Adjustment related to unrealized (gains) losses on available-for-sale securities and derivative instruments	227.1	-102.1	-157.1
Balance at end of year, deferred acquisition costs	$3,077	$2,590	$2,358.10

Insurance_Liabilities_Details

Insurance Liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Liabilities for investment-type insurance contracts:	'	'
Liabilities for individual annuities	$10,582.70	$11,316.20
GICs	10,858.30	10,943.10
Funding agreements	7,642.90	9,077.10
Other investment-type insurance contracts	832.6	787.2
Total liabilities for investment-type insurance contracts	29,916.50	32,123.60
Universal life and other reserves	6,041.80	5,662.90
Contractholder funds	$35,958.30	$37,786.50

Insurance_Liabilities_Details_

Insurance Liabilities (Details 2)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 1998

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2001

Dec. 31, 2013

Dec. 31, 2012

Nov. 30, 2007

Feb. 28, 2006

Mar. 31, 2004

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2006

Dec. 31, 2006

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

USD ($)

USD ($)

Principal Life Insurance Company

1998 Funding agreement program

1998 Funding agreement program

1998 Funding agreement program

2001 Funding agreement program

2001 Funding agreement program

2001 Funding agreement program

2004 Funding agreement program

2004 Funding agreement program

2004 Funding agreement program

2004 Funding agreement program

2004 Funding agreement program

2006 Funding agreement program

2006 Funding agreement program

2006 Funding agreement program

2006 Funding agreement program

2011 Funding agreement program

2011 Funding agreement program

2011 Funding agreement program

item

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

Principal Life Insurance Company

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

EUR (€)

USD ($)

USD ($)

USD ($)

Funding agreement disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of separate funding agreement programs

'

'

5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of funding agreement programs not guaranteed by PFG

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum authorized amount of funding agreements to be issued

'

'

'

'

'

$4,000,000,000

'

'

$7,000,000,000

'

'

'

'

$4,000,000,000

'

'

$5,300,000,000

€ 4,000,000,000

'

'

$5,000,000,000

Funding agreements

7,642,900,000

9,077,100,000

'

370,900,000

1,189,500,000

'

637,600,000

1,598,500,000

'

975,000,000

1,875,600,000

'

'

'

1,278,700,000

1,251,100,000

'

'

2,630,500,000

1,352,300,000

'

Additional maximum authorized amount of funding agreements to be issued

'

'

'

'

'

'

'

'

'

'

'

5,000,000,000

5,000,000,000

'

'

'

'

'

'

'

'

Amount of funding agreement authorization used at time additional amount authorized

'

'

'

'

'

'

'

'

'

'

'

$9,000,000,000

$4,000,000,000

'

'

'

'

'

'

'

'

Insurance_Liabilities_Details_1

Insurance Liabilities (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in unpaid disability and health claims	'	'	'
Balance at beginning of year, Unpaid disability and health claims	$1,066	$1,006.90	$1,061.80
Incurred:	'	'	'
Incurred: Current year	712	711.8	1,074
Incurred: Prior years	1	9.7	-10.8
Total incurred	713	721.5	1,063.20
Payments:	'	'	'
Payments: Current year	432.1	446.3	820.8
Payments: Prior years	202.2	216.1	297.3
Total payments	634.3	662.4	1,118.10
Balance at end of year:	'	'	'
Total balance at end of year, Unpaid disability and health claims: Current year	279.9	265.5	253.2
Total balance at end of year, Unpaid disability and health claims: Prior years	864.8	800.5	753.7
Total balance at end of year, Unpaid disability and health claims	1,144.70	1,066	1,006.90
Supplemental information:	'	'	'
Claim adjustment expense liabilities	43.4	46.6	42.9
Reinsurance recoverables for unpaid claims	$260.10	$239.10	$204.70

Debt_Details

Debt (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Apr. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified			Other recourse short-term debt	Other recourse short-term debt	Line of credit	Line of credit	Line of credit	Line of credit	Line of credit	Commercial paper	Commercial paper
						Principal Financial Services, Inc., Principal Life Insurance Company, and Principal Financial Group, co-borrowers	Principal Life	Principal Financial Services, Inc., Principal Life Insurance Company, Principal Financial Services V (UK) LTD, and Principal Financial Group, co-borrowers	Principal Financial Services, Inc., Principal Life Insurance Company, Principal Financial Services V (UK) LTD, and Principal Financial Group, co-borrowers
Short-Term Debt	'	'	'	'	'	'	'	'	'	'	'
Short-term debt	$150.60	$40.80	$32.80	$40.80	$117.80	'	'	'	'	'	'
Credit facilities	1,105	905	'	'	'	500	300	'	200	'	'
Term of credit facility	'	'	'	'	'	'4 years	'364 days	'3 years	'	'	'
Outstanding borrowings related to credit facilities	150.6	40.8	'	'	'	'	'	'	'	'	'
Assets pledged as support for credit facilities	0	'	'	'	'	'	'	'	'	'	'
Support provided by back-stop facility for commercial paper program (as a percent)	'	'	'	'	'	'	'	'	'	100.00%	100.00%
Weighted-average interest rates on short-term borrowings (as a percent)	4.70%	4.70%	'	'	'	'	'	'	'	'	'
Back-stop facility outstanding balances	'	'	'	'	'	'	'	'	'	$0	$0

Debt_Details_2

Debt (Details 2) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 16, 2012

Dec. 31, 2013

Dec. 31, 2012

18-May-09

Dec. 31, 2013

Dec. 31, 2012

Sep. 05, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 16, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 05, 2006

Oct. 16, 2006

Dec. 31, 2013

Dec. 31, 2012

Sep. 05, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 16, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

In Millions, unless otherwise specified

3.76% notes payable, due 2015

1.85% notes payable, due 2017

1.85% notes payable, due 2017

1.85% notes payable, due 2017

8.875% notes payable, due 2019

8.875% notes payable, due 2019

8.875% notes payable, due 2019

3.3% notes payable, due 2022

3.3% notes payable, due 2022

3.3% notes payable, due 2022

3.125% notes payable, due 2023

3.125% notes payable, due 2023

3.125% notes payable, due 2023

6.05% notes payable, due 2036

6.05% notes payable, due 2036

6.05% notes payable, due 2036

6.05% notes payable, due 2036

4.625% notes payable, due 2042

4.625% notes payable, due 2042

4.625% notes payable, due 2042

4.35% notes payable, due 2043

4.35% notes payable, due 2043

4.35% notes payable, due 2043

8% surplus notes payable, due 2044

8% surplus notes payable, due 2044

Non-recourse mortgages and notes payable

Non-recourse mortgages and notes payable

Long-Term Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt interest rate (as a percent)

'

'

3.76%

1.85%

1.85%

1.85%

8.88%

8.88%

8.88%

3.30%

3.30%

3.30%

3.13%

3.13%

3.13%

6.05%

6.05%

6.05%

6.05%

4.63%

4.63%

4.63%

4.35%

4.35%

4.35%

8.00%

8.00%

5.50%

'

Long-term debt

$2,601.40

$2,671.30

$92.70

$299.80

$299.70

'

$350

$350

'

$299

$298.90

'

$299.60

$299.60

'

$601.60

$601.70

'

'

$299.50

$299.50

'

$299.30

$299.20

'

$99.30

$99.30

$53.30

$30.70

Debt_Details_3

Debt (Details 3) (USD $)

12 Months Ended

0 Months Ended

0 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Nov. 16, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 16, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 16, 2012

Dec. 31, 2013

Dec. 31, 2012

Nov. 16, 2012

Sep. 05, 2012

Dec. 31, 2013

Dec. 31, 2012

Sep. 05, 2012

Dec. 31, 2013

Dec. 31, 2012

Sep. 05, 2012

18-May-09

Sep. 05, 2012

18-May-09

Dec. 31, 2013

Dec. 31, 2012

18-May-09

Aug. 15, 2009

Dec. 31, 2013

Dec. 31, 2012

Dec. 05, 2006

Oct. 16, 2006

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

1.85% notes payable, due 2017

1.85% notes payable, due 2017

1.85% notes payable, due 2017

3.125% notes payable, due 2023

3.125% notes payable, due 2023

3.125% notes payable, due 2023

4.35% notes payable, due 2043

4.35% notes payable, due 2043

4.35% notes payable, due 2043

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

3.3% notes payable, due 2022

3.3% notes payable, due 2022

3.3% notes payable, due 2022

4.625% notes payable, due 2042

4.625% notes payable, due 2042

4.625% notes payable, due 2042

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

7.875% notes payable, due 2014

7.875% notes payable, due 2014

8.875% notes payable, due 2019

8.875% notes payable, due 2019

8.875% notes payable, due 2019

8.2% notes payable, due 2009

6.05% notes payable, due 2036

6.05% notes payable, due 2036

6.05% notes payable, due 2036

6.05% notes payable, due 2036

Long-Term Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt interest rate (as a percent)

'

'

'

'

1.85%

1.85%

1.85%

3.13%

3.13%

3.13%

4.35%

4.35%

4.35%

'

3.30%

3.30%

3.30%

4.63%

4.63%

4.63%

'

'

7.88%

8.88%

8.88%

8.88%

'

6.05%

6.05%

6.05%

6.05%

Long-term debt issued

'

'

'

$900

'

'

$300

'

'

$300

'

'

$300

$600

'

'

$300

'

'

$300

$750

'

$400

'

'

$350

'

'

'

$100

$500

Principal repayments of long-term debt

$218.20

$450.60

$12.20

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$400

'

'

'

'

$440.90

'

'

'

'

Debt_Details_4

Debt (Details 4) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 10, 1994	Dec. 31, 2012	Nov. 03, 2010
In Millions, unless otherwise specified	8% surplus notes payable, due 2044	8% surplus notes payable, due 2044	8% surplus notes payable, due 2044	8% surplus notes payable, due 2044	8% surplus notes payable, due 2044	8% surplus notes payable, due 2044	3.76% notes payable, due 2015	3.76% notes payable, due 2015
			Principal Life Insurance Company Only	Principal Life Insurance Company Only	Principal Life Insurance Company Only	Principal Life Insurance Company Only		Principal International de Chile S.A.
Long-Term Debt	'	'	'	'	'	'	'	'
Long-term debt issued	'	'	'	'	'	$100	'	$98.90
Long-term debt interest rate (as a percent)	8.00%	8.00%	'	'	'	8.00%	3.76%	'
Monetary unit used for denominating Chilean debt	'	'	'	'	'	'	'	'Unidades de Formento ("UF")
Spread on UF interest rate basis for Chilean debt (as a percent)	'	'	'	'	'	'	'	3.76%
Interest expense	'	'	8	8	8	'	'	'
Redemption price of par on or after March 1, 2014 (as a percent)	'	'	102.30%	'	'	'	'	'
Redemption price premium (as a percent)	'	'	2.30%	'	'	'	'	'
Period for redemption price premium	'	'	'10 years	'	'	'	'	'
Redemption price of principal amount plus interest accrued on or after March 1, 2024 (as a percent)	'	'	100.00%	'	'	'	'	'
Principal amount of notes approved for early redemption	'	'	$100	'	'	'	'	'
Approved redemption price of par (as a percent)	'	'	102.30%	'	'	'	'	'

Debt_Details_5

Debt (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2013
Non-recourse mortgages and notes payable	'	'
Long-Term Debt	'	'
Outstanding principal balances per real estate development, low end of range	$0.30	$1.60
Outstanding principal balances per real estate development, high end of range	9.2	20.1
Interest rates per real estate development (as a percent)	'	5.50%
Interest rates per real estate development, low end of range (as a percent)	5.50%	'
Interest rates per real estate development, high end of range (as a percent)	5.80%	'
Real estate	54.2	101.4
Other mortgages and notes payable	'	'
Long-Term Debt	'	'
Long-term debt obligation assumed with purchase of WM Advisors, Inc.	$1.20	$0.20

Debt_Details_6

Debt (Details 6) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Future maturities of long-term debt	'	'
Year 1: Long-term debt maturities	$0.30	'
Year 2: Long-term debt maturities	5.3	'
Year 4: Long-term debt maturities	299.8	'
Year 6 and thereafter: Long-term debt maturities	2,296	'
Long-term debt	$2,601.40	$2,671.30

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes	'	'	'	'	'	'	'
Current income taxes (benefits): U.S. federal	'	'	'	'	$109.50	($66.90)	$115.40
Current income taxes (benefits): State	'	'	'	'	7.7	-4.7	7.2
Current income taxes (benefits): Foreign	'	'	'	'	69.7	48.7	44.4
Current income taxes (benefits): Tax benefit of operating loss carryforwards	'	'	'	'	-134.1	-73.7	-0.2
Total current income taxes (benefits)	'	'	'	'	52.8	-96.6	166.8
Deferred income taxes (benefits): U.S. federal	'	'	'	'	155.1	221.3	43.9
Deferred income taxes (benefits): State	'	'	'	'	-3.1	-1.7	-2.6
Deferred income taxes (benefits): Foreign	'	'	'	'	-16.9	11.6	-9.8
Deferred income taxes (benefits)	'	'	'	'	135.1	231.2	31.5
Income taxes (benefits)	$34.20	($7.20)	$50.90	$56.70	$187.90	$134.60	$198.30

Income_Taxes_Details_2

Income Taxes (Details 2) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net deferred income taxes by jurisdiction	'	'	'	'	'	'	'
Net deferred income tax assets	$20.80	'	'	'	$49.60	$20.80	'
Deferred income taxes	-600	'	'	'	-824	-600	'
Total net deferred income tax assets (liabilities)	-579.2	'	'	'	-774.4	-579.2	'
Current income taxes (benefits):	'	'	'	'	'	'	'
U.S. federal	'	'	'	'	109.5	-66.9	115.4
Total current income taxes (benefits)	'	'	'	'	52.8	-96.6	166.8
Deferred income taxes (benefits)	'	'	'	'	135.1	231.2	31.5
Income taxes (benefits)	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Reconciliation between the U.S. corporate income tax rate and the effective income tax rate from continuing operations	'	'	'	'	'	'	'
U.S. corporate statutory income tax rate (as a percent)	'	'	'	'	35.00%	35.00%	35.00%
Dividends received deduction (as a percent)	'	'	'	'	-10.00%	-10.00%	-9.00%
Impact of equity method presentation (as a percent)	'	'	'	'	-3.00%	-4.00%	-4.00%
Interest exclusion from taxable income (as a percent)	'	'	'	'	-2.00%	-2.00%	-3.00%
Foreign tax rate differential	'	'	'	'	-2.00%	-2.00%	'
Impact of court ruling on some uncertain tax positions (as a percent)	'	'	'	'	'	'	7.00%
Other income tax rate impacts (as a percent)	'	'	'	'	-1.00%	-3.00%	-3.00%
Effective income tax rate (as a percent)	'	'	'	'	17.00%	14.00%	23.00%
Changes in Unrecognized Tax Benefits	'	'	'	'	'	'	'
Beginning balance, Unrecognized tax benefits	'	'	'	114.3	119.5	114.3	'
Additions based on tax positions related to the current year	'	'	'	'	10.5	10.5	'
Additions for tax positions of prior years	'	'	'	'	10.9	4.4	'
Reductions for tax positions related to the current year	'	'	'	'	-3.3	-4.2	'
Reductions for tax positions of prior years	'	'	'	'	-28.7	-5.5	'
Ending balance, Unrecognized tax benefits	119.5	'	'	'	108.9	119.5	114.3
Amount of unrecognized tax benefits that would reduce the effective income tax rate, if recognized	'	'	'	'	55.4	'	'
Accumulated pre-tax interest and penalties related to unrecognized tax benefits	44.1	'	'	'	37	44.1	'
Increase in gross deferred income tax assets	'	'	'	'	138.9	'	'
Increase in gross deferred tax liabilities	'	'	'	'	138.9	'	'
Deferred income tax assets:	'	'	'	'	'	'	'
Insurance liabilities	544	'	'	'	241.1	544	'
Investments, including derivative liabilities	530.5	'	'	'	464.2	530.5	'
Net operating and capital loss carryforwards	386.2	'	'	'	339.8	386.2	'
Employee benefits	491.9	'	'	'	320.6	491.9	'
Other deferred income tax assets	55.9	'	'	'	90.4	55.9	'
Gross deferred income tax assets	2,008.50	'	'	'	1,456.10	2,008.50	'
Valuation allowance	-2.7	'	'	'	-0.7	-2.7	'
Total deferred income tax assets	2,005.80	'	'	'	1,455.40	2,005.80	'
Deferred income tax liabilities:	'	'	'	'	'	'	'
Deferred income tax liabilities: Deferred acquisition costs	-635.3	'	'	'	-807.2	-635.3	'
Investments, including derivative assets	-562.7	'	'	'	-418.3	-562.7	'
Net unrealized gains on available-for-sale securities	-1,114.90	'	'	'	-584.5	-1,114.90	'
Deferred income tax liabilities: Real estate	-102	'	'	'	-117.3	-102	'
Intangible assets	-160	'	'	'	-297.7	-160	'
Other deferred income tax liabilities	-10.1	'	'	'	-4.8	-10.1	'
Total deferred income tax liabilities	-2,585	'	'	'	-2,229.80	-2,585	'
Total net deferred income tax assets (liabilities)	-579.2	'	'	'	-774.4	-579.2	'
Deferred income tax disclosures	'	'	'	'	'	'	'
Net operating loss and tax credit carryforwards attributed to captive reinsurance company included in consolidated U.S. federal income tax return	988.1	'	'	'	670.8	988.1	'
Valuation allowances on income tax benefits associated with foreign net operating loss carryforwards	2.3	'	'	'	0.7	2.3	'
Accumulated but undistributed earnings from operations of foreign subsidiaries for which U.S. federal and state deferred income taxes have not been provided	551.1	'	'	'	693.7	551.1	'
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	'	'
Valuation allowance provided for the deferred tax asset attributable to net operating losses of captive reinsurance companies	'	'	'	'	0	'	'
Current income tax receivables associated with outstanding audit issues	'	'	'	'	'	'	'
Current income tax (receivables) payables associated with outstanding audit issues	-334.6	'	'	'	-329.9	-334.6	'
U.S. Federal	'	'	'	'	'	'	'
Net deferred income taxes by jurisdiction	'	'	'	'	'	'	'
Deferred income taxes	-446.2	'	'	'	-503.4	-446.2	'
State	'	'	'	'	'	'	'
Net deferred income taxes by jurisdiction	'	'	'	'	'	'	'
Net deferred income tax assets	3.9	'	'	'	'	3.9	'
Deferred income taxes	'	'	'	'	-1.5	'	'
Deferred income tax disclosures-operating loss carryforwards	'	'	'	'	'	'	'
Net operating loss carryforwards	328.6	'	'	'	397.7	328.6	'
Foreign	'	'	'	'	'	'	'
Net deferred income taxes by jurisdiction	'	'	'	'	'	'	'
Net deferred income tax assets	16.9	'	'	'	49.6	16.9	'
Deferred income taxes	-153.8	'	'	'	-319.1	-153.8	'
Deferred income tax disclosures-operating loss carryforwards	'	'	'	'	'	'	'
Net operating loss carryforwards	$70.60	'	'	'	$95.70	$70.60	'

Employee_and_Agent_Benefits_De

Employee and Agent Benefits (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	($511.60)	$196.10	$266
Pension benefits	'	'	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	57.1	47	44
Interest cost	103.8	109.1	108.5
Expected return on plan assets	-127.4	-114.6	-114.4
Amortization of prior service (benefit) cost	-8.7	-9.4	-9.7
Recognized net actuarial (gain) loss	118.5	90.9	65.8
Amount recognized due to special events	'	-0.7	-1.4
Net periodic benefit cost (income)	143.3	122.3	92.8
Eligibility age	'21 years	'	'
Period of employment used to calculate average annual compensation for the final average pay benefit	'5 years	'	'
Maximum age used to calculate a partial benefit accrual of final average pay benefits	'65 years	'	'
Minimum years of potential service used to calculate a partial benefit accrual of final average pay benefits	'35 years	'	'
Change in benefit obligation	'	'	'
Benefit obligation at beginning of year	-2,638	-2,158.40	'
Service cost	-57.1	-47	'
Interest cost	-103.8	-109.1	'
Actuarial gain (loss)	279.2	-407.1	'
Benefits paid	79.5	76.4	'
Other changes in benefit obligation	'	7.2	'
Benefit obligation at end of year	-2,440.20	-2,638	-2,158.40
Change in plan assets	'	'	'
Fair value of plan assets at beginning of year	1,682.10	1,429	'
Actual return on plan assets	199.8	222.6	'
Employer contribution	123.2	106.9	'
Benefits paid	-79.5	-76.4	'
Fair value of plan assets at end of year	1,925.60	1,682.10	1,429
Amount recognized in statement of financial position	'	'	'
Amount recognized in other liabilities	-514.6	-955.9	'
Total assets (liabilities) recognized in statement of financial position	-514.6	-955.9	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	391.1	861.2	'
Prior service (benefit) cost	-11.8	-20.4	'
Pre-tax accumulated other comprehensive (income) loss	379.3	840.8	'
Additional defined benefit plan disclosures	'	'	'
Accumulated benefit obligation	2,287.40	2,469.10	'
Impact from Exit of Group Medical Insurance Business	'	'	'
Curtailment (gain) loss	'	-0.7	-1.4
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	2,440.20	2,638	'
Accumulated benefit obligation for defined benefit plans with an accumulated benefit obligation in excess of plan assets	2,287.40	2,469.10	'
Fair value of plan assets for defined benefit plans with an accumulated benefit obligation in excess of plan assets	1,925.60	1,682.10	'
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-351.7	292.1	'
Amortization of net gain (loss)	-118.5	-90.9	'
Amortization of prior service benefit (cost)	8.7	10.1	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-461.5	211.3	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	-318.2	333.6	'
Estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year	'	'	'
Estimated net actuarial (gain) loss that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year	50.6	'	'
Estimated prior service cost (benefit) that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year	-4.8	'	'
Qualified defined benefit pension plans	'	'	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	50.4	42.3	'
Interest cost	88.2	92.8	'
Expected return on plan assets	-127.4	-114.6	'
Amortization of prior service (benefit) cost	-6.1	-6.3	'
Recognized net actuarial (gain) loss	104.4	84.8	'
Amount recognized due to special events	'	-0.4	'
Net periodic benefit cost (income)	109.5	98.6	'
Change in plan assets	'	'	'
Fair value of plan assets at beginning of year	1,682.10	'	'
Fair value of plan assets at end of year	1,925.60	1,682.10	'
Amount recognized in statement of financial position	'	'	'
Amount recognized in other liabilities	-138.6	-557.7	'
Total assets (liabilities) recognized in statement of financial position	-138.6	-557.7	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	298.3	725	'
Prior service (benefit) cost	-6.5	-12.5	'
Pre-tax accumulated other comprehensive (income) loss	291.8	712.5	'
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%	'	'
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-322.4	223.5	'
Amortization of net gain (loss)	-104.4	-84.8	'
Amortization of prior service benefit (cost)	6.1	6.7	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-420.7	145.4	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	-311.2	244	'
Nonqualified defined benefit pension plans	'	'	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	6.7	4.7	'
Interest cost	15.6	16.3	'
Amortization of prior service (benefit) cost	-2.6	-3.1	'
Recognized net actuarial (gain) loss	14.1	6.1	'
Amount recognized due to special events	'	-0.3	'
Net periodic benefit cost (income)	33.8	23.7	'
Amount recognized in statement of financial position	'	'	'
Amount recognized in other liabilities	-376	-398.2	'
Total assets (liabilities) recognized in statement of financial position	-376	-398.2	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	92.8	136.2	'
Prior service (benefit) cost	-5.3	-7.9	'
Pre-tax accumulated other comprehensive (income) loss	87.5	128.3	'
Additional defined benefit plan disclosures	'	'	'
Market value of assets held in Rabbi trusts for benefit of nonqualified pension plan participants	304.3	300.8	'
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-29.3	68.6	'
Amortization of net gain (loss)	-14.1	-6.1	'
Amortization of prior service benefit (cost)	2.6	3.4	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-40.8	65.9	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	-7	89.6	'
Other postretirement benefits	'	'	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	1	1.3	1.2
Interest cost	5.7	8.2	8.9
Expected return on plan assets	-28.8	-33.5	-34.1
Amortization of prior service (benefit) cost	-25.9	-28.6	-29.3
Recognized net actuarial (gain) loss	1	0.9	0.4
Amount recognized due to special events	'	-3.5	-5.1
Net periodic benefit cost (income)	-47	-55.2	-58
Eligibility age	'57 years	'	'
Eligibility service period	'10 years	'	'
Change in benefit obligation	'	'	'
Benefit obligation at beginning of year	-147.8	-165.1	'
Service cost	-1	-1.3	'
Interest cost	-5.7	-8.2	'
Actuarial gain (loss)	7.9	21.2	'
Participant contributions	-6.8	-6.6	'
Benefits paid	13.6	13	'
Other changes in benefit obligation	-0.8	-0.8	'
Benefit obligation at end of year	-140.6	-147.8	-165.1
Change in plan assets	'	'	'
Fair value of plan assets at beginning of year	519.7	466.6	'
Actual return on plan assets	95.9	58.6	'
Employer contribution	4.2	0.9	'
Participant contributions	6.8	6.6	'
Benefits paid	-13.6	-13	'
Fair value of plan assets at end of year	613	519.7	466.6
Amount recognized in statement of financial position	'	'	'
Amount recognized in other assets	473	372.5	'
Amount recognized in other liabilities	-0.6	-0.6	'
Total assets (liabilities) recognized in statement of financial position	472.4	371.9	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	-83.1	-7.1	'
Prior service (benefit) cost	-56.2	-82.1	'
Pre-tax accumulated other comprehensive (income) loss	-139.3	-89.2	'
Additional defined benefit plan disclosures	'	'	'
Medicare subsidies received, accrued and included in service cost	0.8	0.8	0.9
Minimum age for voluntarily drop medical coverage	'65 years	'	'
Impact from Exit of Group Medical Insurance Business	'	'	'
Curtailment (gain) loss	'	-3.5	-5.1
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	1.5	1.7	'
Fair value of plan assets for defined benefit plans with an accumulated benefit obligation in excess of plan assets	0.9	1.1	'
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-75	-46.4	'
Amortization of net gain (loss)	-1	-0.9	'
Amortization of prior service benefit (cost)	25.9	32.1	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-50.1	-15.2	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	-97.1	-70.4	'
Estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year	'	'	'
Estimated net actuarial (gain) loss that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year	-3.4	'	'
Estimated prior service cost (benefit) that will be amortized from accumulated other comprehensive income into net periodic benefit cost during the next fiscal year	($20.30)	'	'
Retiree health benefits	'	'	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Participant contributions as a percent of expected cost of coverage for employees hired prior to January 1, 2002, who retired on or after January 1, 2011 (as a percent)	60.00%	'	'

Employee_and_Agent_Benefits_De1

Employee and Agent Benefits (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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)	4.90%	4.00%	'
Rate of compensation increase: Benefit obligation (as a percent)	4.80%	4.80%	'
Weighted-average assumptions used to determine net periodic benefit cost	'	'	'
Discount rate: Net periodic benefit cost (as a percent)	4.00%	5.15%	5.65%
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)	7.50%	8.00%	8.00%
Rate of compensation increase: Net periodic benefit cost (as a percent)	4.80%	5.00%	5.00%
Other postretirement benefits	'	'	'
Effect of one-percentage-point change in assumed health care cost trend rates	'	'	'
Effect on total of service cost and interest cost components of a one-percentage-point increase in assumed health care cost trend rates	0.3	'	'
Effect on total of service cost and interest cost components of a one-percentage-point decrease in assumed health care cost trend rates	-0.3	'	'
Effect on accumulated postretirement benefit obligation of a one-percentage-point increase in assumed health care cost trend rates	-6.1	'	'
Effect on accumulated postretirement benefit obligation of a one-percentage-point decrease in assumed health care cost trend rates	5.3	'	'
Weighted-average assumptions used to determine benefit obligations as disclosed under the Obligations and Funded Status section	'	'	'
Discount rate: Benefit obligation (as a percent)	4.90%	4.00%	'
Rate of compensation increase: Benefit obligation (as a percent)	4.83%	4.83%	'
Weighted-average assumptions used to determine net periodic benefit cost	'	'	'
Discount rate: Net periodic benefit cost (as a percent)	4.00%	5.15%	5.65%
Expected long-term return on plan assets: Net periodic benefit cost (as a percent)	5.62%	7.30%	7.30%
Rate of compensation increase: Net periodic benefit cost (as a percent)	4.83%	5.00%	5.00%
Assumed Health Care Cost Trend Rates	'	'	'
Health care cost trend rate assumed for next year under age 65 (as a percent)	8.00%	8.00%	'
Health care cost trend rate assumed for next year age 65 and over (as a percent)	6.00%	7.00%	'
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate) (as a percent)	4.50%	4.50%	'
Year that the health care cost trend rate reaches the ultimate trend rate under age 65 (calendar year)	'2020	'2019	'
Year that the health care cost trend rate reaches the ultimate trend rate age 65 and over (calendar year)	'2019	'2017	'
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)	5.40%	'	'
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)	7.75%	'	'
Long-term care 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)	5.85%	'	'

Employee_and_Agent_Benefits_De2

Employee and Agent Benefits (Details 3) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Pension benefits	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	$1,925.60	$1,682.10	$1,429	'
Qualified defined benefit pension plans	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	1,925.60	1,682.10	'	'
Qualified defined benefit pension plans | U.S. large cap equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	414	601.8	'	'
Qualified defined benefit pension plans | U.S. small/mid cap equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	102.9	156.2	'	'
Qualified defined benefit pension plans | Balance asset allocation portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	96.9	82.4	'	'
Qualified defined benefit pension plans | International equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	171	273.9	'	'
Qualified defined benefit pension plans | Fixed income security portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	1,048.50	486.6	'	'
Qualified defined benefit pension plans | Direct real estate investments	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	92.3	81.2	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	1,925.60	1,682.10	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2 | U.S. large cap equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	414	601.8	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2 | U.S. small/mid cap equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	102.9	156.2	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2 | Balance asset allocation portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	96.9	82.4	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2 | International equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	171	273.9	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2 | Fixed income security portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	1,048.50	486.6	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 2 | Direct real estate investments	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	92.3	81.2	'	'
Qualified defined benefit pension plans | Fair value hierarchy Level 3 | Direct real estate investments	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	'	'	'	84.7
Other postretirement benefits	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	613	519.7	466.6	'
Fair value of plan assets included in trust owned life insurance contract	77.7	59.4	'	'
Other postretirement benefits | Cash and cash equivalents	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	4.7	1.9	'	'
Other postretirement benefits | U.S. equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	351.6	260.8	'	'
Other postretirement benefits | International equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	60	51.4	'	'
Other postretirement benefits | Fixed income investment funds	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	157.9	163.5	'	'
Other postretirement benefits | Principal Life general account investment	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	38.8	42.1	'	'
Other postretirement benefits | Fair value hierarchy Level 1	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	496.5	418.2	'	'
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	4.7	1.9	'	'
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	288	213.5	'	'
Other postretirement benefits | Fair value hierarchy Level 1 | International equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	45.9	39.3	'	'
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	157.9	163.5	'	'
Other postretirement benefits | Fair value hierarchy Level 2	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	77.7	59.4	'	'
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	63.6	47.3	'	'
Other postretirement benefits | Fair value hierarchy Level 2 | International equity portfolios	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	14.1	12.1	'	'
Other postretirement benefits | Fair value hierarchy Level 3	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	38.8	42.1	'	'
Other postretirement benefits | Fair value hierarchy Level 3 | Principal Life general account investment	'	'	'	'
Defined benefit plan, fair value of plan assets	'	'	'	'
Fair value of plan assets	$38.80	$42.10	$42.50	$44.50

Employee_and_Agent_Benefits_De3

Employee and Agent Benefits (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension benefits	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	$1,925.60	$1,682.10	$1,429
Qualified defined benefit pension plans	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	1,925.60	1,682.10	'
Qualified defined benefit pension plans | Direct real estate investments	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	92.3	81.2	'
Qualified defined benefit pension plans | Fixed income security portfolios	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	1,048.50	486.6	'
Qualified defined benefit pension plans | Fair value hierarchy Level 3 | Direct real estate investments	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at beginning of year	'	'	84.7
Actual return gains (losses) on plan assets relating to assets still held at the reporting date	'	'	1.6
Net purchases, sales and settlements	'	'	1
Transfers out of Level 3	'	'	-87.3
Other postretirement benefits	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	613	519.7	466.6
Other postretirement benefits | Principal Life general account investment	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	38.8	42.1	'
Other postretirement benefits | Fair value hierarchy Level 3	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at end of year	38.8	42.1	'
Other postretirement benefits | Fair value hierarchy Level 3 | Principal Life general account investment	'	'	'
Change in Level 3 fair value measurement rollforward, plan assets	'	'	'
Fair value of plan assets at beginning of year	42.1	42.5	44.5
Actual return gains (losses) on plan assets relating to assets still held at the reporting date	1.1	3.1	3
Net purchases, sales and settlements	-4.4	-3.5	-5
Fair value of plan assets at end of year	$38.80	$42.10	$42.50

Employee_and_Agent_Benefits_De4

Employee and Agent Benefits (Details 5)	12 Months Ended
	Dec. 31, 2013
Qualified defined benefit pension plans | U.S. equity portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'0%
Qualified defined benefit pension plans | U.S. equity portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'45%
Qualified defined benefit pension plans | International equity portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'0%
Qualified defined benefit pension plans | International equity portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'15%
Qualified defined benefit pension plans | Fixed income security portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'30%
Qualified defined benefit pension plans | Fixed income security portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'100%
Qualified defined benefit pension plans | Real estate investment portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'0%
Qualified defined benefit pension plans | Real estate investment portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'10%
Other postretirement benefits | U.S. equity portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'45%
Other postretirement benefits | U.S. equity portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'65%
Other postretirement benefits | International equity portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'5%
Other postretirement benefits | International equity portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'15%
Other postretirement benefits | Fixed income security portfolios | Minimum	'
Asset category target allocation	'
Asset category target allocation	'30%
Other postretirement benefits | Fixed income security portfolios | Maximum	'
Asset category target allocation	'
Asset category target allocation	'50%

Employee_and_Agent_Benefits_De5

Employee and Agent Benefits (Details 6) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Pension benefits	'
Contributions	'
The low end of the range of possible contributions to be made during the next fiscal year to the qualified and nonqualified pension plans combined	$125
The high end of the range of possible contributions to be made during the next fiscal year to the qualified and nonqualified pension plans combined	175
Estimated Future Benefit Payments	'
Estimated future benefit payments, Year 1	98.7
Estimated future benefit payments, Year 2	102.9
Estimated future benefit payments, Year 3	108.2
Estimated future benefit payments, Year 4	114.4
Estimated future benefit payments, Year 5	120.6
Estimated future benefit payments, Years 6-10	708.4
Other postretirement benefits	'
Estimated Future Benefit Payments	'
Estimated future benefit payments, Year 1	18.1
Estimated future benefit payments, Year 2	18.6
Estimated future benefit payments, Year 3	19
Estimated future benefit payments, Year 4	19.3
Estimated future benefit payments, Year 5	19.4
Estimated future benefit payments, Years 6-10	99.1
Amount of Medicare Part D subsidy receipts	'
Medicare Part D subsidy receipts, Year 1	1
Medicare Part D subsidy receipts, Year 2	1
Medicare Part D subsidy receipts, Year 3	1
Medicare Part D subsidy receipts, Year 4	1.1
Medicare Part D subsidy receipts, Year 5	1.1
Medicare Part D subsidy receipts, Years 6-10	$5.10

Employee_and_Agent_Benefits_De6

Employee and Agent Benefits (Details 7) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	($511.60)	$196.10	$266
Pension benefits	'	'	'
Amount recognized in statement of financial position	'	'	'
Amount recognized in other liabilities	-514.6	-955.9	'
Total assets (liabilities) recognized in statement of financial position	-514.6	-955.9	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	391.1	861.2	'
Prior service (benefit) cost	-11.8	-20.4	'
Pre-tax accumulated other comprehensive (income) loss	379.3	840.8	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	57.1	47	44
Interest cost	103.8	109.1	108.5
Expected return on plan assets	-127.4	-114.6	-114.4
Amortization of prior service (benefit) cost	-8.7	-9.4	-9.7
Recognized net actuarial (gain) loss	118.5	90.9	65.8
Amount recognized due to special events	'	-0.7	-1.4
Net periodic benefit cost (income)	143.3	122.3	92.8
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-351.7	292.1	'
Amortization of net gain (loss)	-118.5	-90.9	'
Amortization of prior service benefit (cost)	8.7	10.1	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-461.5	211.3	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	-318.2	333.6	'
Qualified defined benefit pension plans	'	'	'
Amount recognized in statement of financial position	'	'	'
Amount recognized in other liabilities	-138.6	-557.7	'
Total assets (liabilities) recognized in statement of financial position	-138.6	-557.7	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	298.3	725	'
Prior service (benefit) cost	-6.5	-12.5	'
Pre-tax accumulated other comprehensive (income) loss	291.8	712.5	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	50.4	42.3	'
Interest cost	88.2	92.8	'
Expected return on plan assets	-127.4	-114.6	'
Amortization of prior service (benefit) cost	-6.1	-6.3	'
Recognized net actuarial (gain) loss	104.4	84.8	'
Amount recognized due to special events	'	-0.4	'
Net periodic benefit cost (income)	109.5	98.6	'
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-322.4	223.5	'
Amortization of net gain (loss)	-104.4	-84.8	'
Amortization of prior service benefit (cost)	6.1	6.7	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-420.7	145.4	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	-311.2	244	'
Nonqualified defined benefit pension plans	'	'	'
Amount recognized in statement of financial position	'	'	'
Amount recognized in other liabilities	-376	-398.2	'
Total assets (liabilities) recognized in statement of financial position	-376	-398.2	'
Amount recognized in accumulated other comprehensive (income) loss	'	'	'
Total net actuarial (gain) loss	92.8	136.2	'
Prior service (benefit) cost	-5.3	-7.9	'
Pre-tax accumulated other comprehensive (income) loss	87.5	128.3	'
Components of Net Periodic Benefit Cost (Income)	'	'	'
Service cost	6.7	4.7	'
Interest cost	15.6	16.3	'
Amortization of prior service (benefit) cost	-2.6	-3.1	'
Recognized net actuarial (gain) loss	14.1	6.1	'
Amount recognized due to special events	'	-0.3	'
Net periodic benefit cost (income)	33.8	23.7	'
Other changes recognized in accumulated other comprehensive (income) loss	'	'	'
Net actuarial (gain) loss	-29.3	68.6	'
Amortization of net gain (loss)	-14.1	-6.1	'
Amortization of prior service benefit (cost)	2.6	3.4	'
Total recognized in pre-tax accumulated other comprehensive (income) loss	-40.8	65.9	'
Total recognized in net periodic benefit cost and pre-tax accumulated other comprehensive (income) loss	($7)	$89.60	'

Employee_and_Agent_Benefits_De7

Employee and Agent Benefits (Details 8) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Qualified defined contribution plan	'	'	'
Defined Contribution Plan Disclosures	'	'	'
Maximum amount of compensation eligible participants could contribute to defined contribution plans	$17,500	'	'
Amount contributed by the employer to defined contribution plans	39,800,000	37,300,000	36,300,000
Qualified defined contribution plan | Grandfathered Choice Participant	'	'	'
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%	'	'
Qualified defined contribution plan | All other participants	'	'	'
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%	'	'
Nonqualified deferred compensation plan	'	'	'
Defined Contribution Plan Disclosures	'	'	'
Amount contributed by the employer to defined contribution plans	$5,000,000	$4,600,000	$3,500,000
Nonqualified deferred compensation plan | Grandfathered Choice Participant	'	'	'
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%	'	'
Nonqualified deferred compensation plan | All other participants	'	'	'
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_and_I2

Contingencies, Guarantees and Indemnifications (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2008
Loss contingencies - disclosures	'	'	'
Proceeds from termination of certain structured transactions and the resulting prepayment	'	'	$440
Amount, including interest, attempted to be recovered	500	'	'
Estimated losses accrued related to legal matters	0	'	'
Maximum exposure under guarantees	251	'	'
Guaranty Funds	'	'	'
Undiscounted liability balance for guaranty fund assessments	22.5	31	'
Premium tax offsets	$11.50	$16.50	'

Contingencies_Guarantees_and_I3

Contingencies, Guarantees and Indemnifications (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating leases	'	'	'
Operating lease rental expense	$36.30	$41.90	$51.10
Operating lease obligations	'	'	'
Year 1: Operating lease obligations	42.3	'	'
Year 2: Operating lease obligations	37	'	'
Year 3: Operating lease obligations	30.9	'	'
Year 4: Operating lease obligations	23.2	'	'
Year 5: Operating lease obligations	10.8	'	'
Year 6 and thereafter: Operating lease obligations	53.9	'	'
Total operating lease obligations	198.1	'	'
Less: Future sublease rental income on noncancelable leases	7.7	'	'
Total future minimum lease payments	190.4	'	'
Capital leases	'	'	'
Capital lease gross asset balance	42.6	35.5	'
Capital lease accumulated depreciation	16.1	11.5	'
Capital lease depreciation expense	10.5	7.9	4.4
Capital lease future minimum lease payments	'	'	'
Year 1: Capital lease future minimum lease payments	7.2	'	'
Year 2: Capital lease future minimum lease payments	6.1	'	'
Year 3: Capital lease future minimum lease payments	4.5	'	'
Year 4: Capital lease future minimum lease payments	1.7	'	'
Year 5: Capital lease future minimum lease payments	0.1	'	'
Total capital lease future minimum lease payments	19.6	'	'
Less: Amounts representing interest	0.6	'	'
Net present value of minimum lease payments	$19	'	'

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)

12 Months Ended

0 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 30, 2013

Sep. 30, 2013

Jul. 02, 2013

Apr. 03, 2013

Dec. 31, 2012

Oct. 03, 2012

Jul. 02, 2012

Mar. 30, 2012

Dec. 30, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 30, 2011

Dec. 31, 2013

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred Stock

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock, authorized (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

13

Preferred stock, issued (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

13

Preferred stock, outstanding (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

13

Dividends to preferred stockholders

$33

$33

$33

$8.30

$8.20

$8.30

$8.20

$8.30

$8.20

$8.30

$8.20

$8.30

$8.20

$8.30

$8.20

'

Stockholders_Equity_Details_2

Stockholders' Equity (Details 2) (USD $)

12 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

In Millions, except Per Share data, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 27, 2013

Sep. 27, 2013

Jun. 28, 2013

Mar. 29, 2013

Dec. 28, 2012

Sep. 28, 2012

Jun. 29, 2012

Mar. 30, 2012

Dec. 02, 2011

Feb. 28, 2013

31-May-12

Feb. 29, 2012

Nov. 30, 2011

Aug. 31, 2011

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 30, 2013

Sep. 30, 2013

Jul. 02, 2013

Apr. 03, 2013

Dec. 31, 2012

Oct. 03, 2012

Jul. 02, 2012

Mar. 30, 2012

Dec. 30, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 30, 2011

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2010

Dec. 30, 2013

Sep. 30, 2013

Jul. 02, 2013

Apr. 03, 2013

Dec. 31, 2012

Oct. 03, 2012

Jul. 02, 2012

Mar. 30, 2012

Dec. 30, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 30, 2011

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2010

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Common stock

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series A

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Series B

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred stock

Preferred Stock

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock dividend rate per annum (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.56%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.52%

'

'

Preferred stock redemption price (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$25

'

'

Preferred stock aggregate redemption amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$300

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$250

'

'

Preferred stock dividend (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

$1.39

'

'

'

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

$0.41

'

'

'

Quarterly Common Stock Dividend Paid

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends to common stockholders

288.4

231.3

213.7

76.7

76.5

67.6

67.6

61.7

61.6

53.7

54.3

213.7

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividend paid on common stock (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.26

$0.26

$0.23

$0.23

$0.21

$0.21

$0.18

$0.18

'

'

$0.70

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Reconciliation of Outstanding Shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding shares at beginning of period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

293.8

'

'

'

301.1

293.8

301.1

320.4

'

'

'

'

'

'

'

'

'

'

'

'

3

3

3

'

'

'

'

'

'

'

'

'

'

'

'

10

10

10

Shares issued

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.8

3.2

1.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-4.4

-10.5

-21.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding shares at end of period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

295.2

'

'

'

293.8

'

'

'

295.2

293.8

301.1

'

'

'

'

3

'

'

'

'

'

'

'

3

3

3

'

'

'

'

10

'

'

'

'

'

'

'

10

10

10

Common stock share repurchase disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

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'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share repurchase program, maximum authorized amount (in dollars)

'

'

'

'

'

'

'

'

'

'

'

'

$150

$200

$100

$100

$200

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stockholders_Equity_Details_3

Stockholders' Equity (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Comprehensive Income (Loss) Pre-Tax	'	'	'
Net unrealized gains (losses) on available-for-sale securities during the period, pre-tax	($1,686.50)	$1,577.30	$559.40
Reclassification adjustment for (gains) losses on available-for-sale securities included in net income, pre-tax	61.1	107.8	112
Adjustments for assumed changes in amortization patterns related to available-for-sale securities, pre-tax	252.8	-169	-114.9
Adjustments for assumed changes in policyholder liabilities related to available-for-sale securities, pre-tax	575.7	-689.2	-230.3
Net unrealized gains (losses) on available-for-sale securities, pre-tax	-796.9	826.9	326.2
Noncredit component of impairment losses on fixed maturities, available-for-sale during the period, pre-tax	24.5	-17.3	49.9
Adjustments for assumed changes in amortization patterns related to noncredit component of impairment losses on fixed maturities, available-for-sale, pre-tax	-14.4	4	-1.4
Adjustments for assumed changes in policyholder liabilities related to noncredit component of impairment losses on fixed maturities, available-for-sale, pre-tax	'	3.2	'
Noncredit component of impairment losses on fixed maturities, available-for-sale, pre-tax	10.1	-10.1	48.5
Net unrealized gains (losses) on derivative instruments during the period, pre-tax	-46.3	-25.9	39.6
Reclassification adjustment for (gains) losses on derivative instruments included in net income, pre-tax	11.6	3.4	20.7
Adjustments for assumed changes in amortization patterns related to derivative instruments, pre-tax	10.9	25.9	-23.9
Adjustments for assumed changes in policyholder liabilities related to derivative instruments, pre-tax	20.5	-70	'
Net unrealized gains (losses) on derivative instruments, pre-tax	-3.3	-66.6	36.4
Foreign currency translation adjustment, pre-tax	-282.6	-25.4	-130.8
Unrecognized postretirement benefit obligation during the period, pre-tax	426.7	-245.7	-286.7
Amortization of prior service (benefit) cost and actuarial (gain) loss included in net periodic benefit cost, pre-tax	84.9	49.6	20.7
Net unrecognized postretirement benefit obligation, pre-tax	511.6	-196.1	-266
Other comprehensive income (loss), pre-tax	-561.1	528.7	14.3
Other Comprehensive Income (Loss) Tax	'	'	'
Net unrealized gains (losses) on available-for-sale securities during the period, tax	559.5	-520.6	-207.9
Reclassification adjustment for (gains) losses on available-for-sale securities included in net income, tax	-20.9	-38.4	-42.9
Adjustments for assumed changes in amortization patterns related to available-for-sale securities, tax	-88.5	59.1	40.2
Adjustments for assumed changes in policyholder liabilities related to available-for-sale securities, tax	-193.4	230.6	93
Net unrealized gains (losses) on available-for-sale securities, tax	256.7	-269.3	-117.6
Noncredit component of impairment losses on fixed maturities, available-for-sale during the period, tax	-8.3	6.1	-18
Adjustments for assumed changes in amortization patterns related to noncredit component of impairment losses on fixed maturities, available-for-sale, tax	5.1	-1.6	0.5
Adjustments for assumed changes in policyholder liabilities related to noncredit component of impairment losses on fixed maturities, available-for-sale, tax	'	-1.1	'
Noncredit component of impairment losses on fixed maturities, available-for-sale, tax	-3.2	3.4	-17.5
Net unrealized gains (losses) on derivative instruments during the period, tax	16.8	9.1	-13.8
Reclassification adjustment for (gains) losses on derivative instruments included in net income, tax	-4.3	-1.5	-7.4
Adjustments for assumed changes in amortization patterns related to derivative instruments, tax	-3.8	-9.1	8.4
Adjustments for assumed changes in policyholder liabilities related to derivative instruments, tax	-7.2	24.5	'
Net unrealized gains (losses) on derivative instruments, tax	1.5	23	-12.8
Foreign currency translation adjustment, tax	13.2	15.6	-0.1
Unrecognized postretirement benefit obligation during the period, tax	-149.3	86	100.3
Amortization of prior service (benefit) cost and actuarial (gain) loss included in net periodic benefit cost, tax	-29.7	-17.3	-7.2
Net unrecognized postretirement benefit obligation, tax	-179	68.7	93.1
Other comprehensive income (loss), tax	89.2	-158.6	-54.9
Other Comprehensive Income (Loss) After-Tax	'	'	'
Net unrealized gains (losses) on available-for-sale securities during the period	-1,127	1,056.70	351.5
Reclassification adjustment for (gains) losses on available-for-sale securities included in net income	40.2	69.4	69.1
Adjustments for assumed changes in amortization patterns related to available-for-sale securities	164.3	-109.9	-74.7
Adjustments for assumed changes in policyholder liabilities related to available-for-sale securities	382.3	-458.6	-137.3
Net unrealized gains (losses) on available-for-sale securities	-540.2	557.6	208.6
Noncredit component of impairment losses on fixed maturities, available-for-sale during the period	16.2	-11.2	31.9
Adjustments for assumed changes in amortization patterns related to noncredit component of impairment losses on fixed maturities, available-for-sale	-9.3	2.4	-0.9
Adjustments for assumed changes in policyholder liabilities related to noncredit component of impairment losses on fixed maturities, available-for-sale	'	2.1	'
Noncredit component of impairment losses on fixed maturities, available-for-sale	6.9	-6.7	31
Net unrealized gains (losses) on derivative instruments during the period	-29.5	-16.8	25.8
Reclassification adjustment for (gains) losses on derivative instruments included in net income	7.3	1.9	13.3
Adjustments for assumed changes in amortization patterns related to derivative instruments	7.1	16.8	-15.5
Adjustments for assumed changes in policyholder liabilities related to derivative instruments	13.3	-45.5	'
Net unrealized gains (losses) on derivative instruments	-1.8	-43.6	23.6
Foreign currency translation adjustment	-269.4	-9.8	-130.9
Unrecognized postretirement benefit obligation during the period	277.4	-159.7	-186.4
Amortization of prior service (benefit) cost and actuarial (gain) loss included in net periodic benefit cost	55.2	32.3	13.5
Net unrecognized postretirement benefit obligation	332.6	-127.4	-172.9
Other comprehensive income (loss)	($471.90)	$370.10	($40.60)

Stockholders_Equity_Details_4

Stockholders' Equity (Details 4) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	$640.30	'	'
Accumulated other comprehensive income (loss), balance at end of period	'	183.2	640.3	'
Change in redeemable noncontrolling interest rollforward	'	'	'	'
Redeemable noncontrolling interest, balance at beginning of period	'	60.4	22.2	'
Net income (loss) attributable to redeemable noncontrolling interest	'	13.6	1.9	0.2
Reclassification from stockholders' equity	173.9	173.9	'	'
Contributions from redeemable noncontrolling interest	'	1.2	'	'
Redeemable noncontrolling interest assumed related to acquisition	'	'	37.2	22
Distributions to redeemable noncontrolling interest	'	-13.9	-2	'
Purchase of subsidiary shares from redeemable noncontrolling interest	'	-2.4	'	'
Change in redemption value of redeemable noncontrolling interest	'	19.2	'	'
Foreign currency translation adjustment, redeemable noncontrolling interest	'	-4.8	1.1	'
Redeemable noncontrolling interest, balance at end of period	'	247.2	60.4	22.2
Dividend Limitations	'	'	'	'
Statutory dividend limitation as percentage of policyholder surplus (as a percent)	'	10.00%	'	'
Dividends that can be paid in upcoming calendar year without exceeding statutory limitation	'	687.2	'	'
Net unrealized gains (losses) on available-for-sale securities	'	'	'	'
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	1,418.30	860.7	652.1
Other comprehensive income (loss) during the period, net of adjustments	'	-580.4	488.2	139.5
Amounts reclassified from accumulated other comprehensive income (loss)	'	40.2	69.4	69.1
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	-540.2	557.6	208.6
Accumulated other comprehensive income (loss), balance at end of period	'	878.1	1,418.30	860.7
Noncredit component of impairment losses on fixed maturities available-for-sale	'	'	'	'
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	-173.9	-167.2	-198.2
Other comprehensive income (loss) during the period, net of adjustments	'	'	-6.7	'
Amounts reclassified from accumulated other comprehensive income (loss)	'	6.9	'	31
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	6.9	-6.7	31
Accumulated other comprehensive income (loss), balance at end of period	'	-167	-173.9	-167.2
Net unrealized gains (losses) on derivative instruments	'	'	'	'
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	-8.7	34.9	11.3
Other comprehensive income (loss) during the period, net of adjustments	'	-9.1	-45.5	10.3
Amounts reclassified from accumulated other comprehensive income (loss)	'	7.3	1.9	13.3
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	-1.8	-43.6	23.6
Accumulated other comprehensive income (loss), balance at end of period	'	-10.5	-8.7	34.9
Foreign currency translation adjustment	'	'	'	'
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	-106.9	-95.9	34.5
Other comprehensive income (loss) during the period, net of adjustments	'	-254.6	-11	-130.4
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	-254.6	-11	-130.4
Accumulated other comprehensive income (loss), balance at end of period	'	-361.5	-106.9	-95.9
Unrecognized postretirement benefit obligations	'	'	'	'
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	-488.5	-361.1	-188.2
Other comprehensive income (loss) during the period, net of adjustments	'	277.4	-159.7	-186.4
Amounts reclassified from accumulated other comprehensive income (loss)	'	55.2	32.3	13.5
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	332.6	-127.4	-172.9
Accumulated other comprehensive income (loss), balance at end of period	'	-155.9	-488.5	-361.1
Accumulated other comprehensive income (loss)	'	'	'	'
Change in accumulated other comprehensive income (loss) rollforward	'	'	'	'
Accumulated other comprehensive income (loss), balance at beginning of period	'	640.3	271.4	311.5
Other comprehensive income (loss) during the period, net of adjustments	'	-566.7	265.3	-167
Amounts reclassified from accumulated other comprehensive income (loss)	'	109.6	103.6	126.9
Other comprehensive income (loss) attributable to Principal Financial Group, Inc.	'	-457.1	368.9	-40.1
Accumulated other comprehensive income (loss), balance at end of period	'	$183.20	$640.30	$271.40

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Assets (liabilities) measured at fair value on a recurring basis	'	'
Derivative assets	$665.10	$1,016.70
Separate account assets	130,018.40	81,653.80
Investment-type insurance contracts	-6.9	-170.5
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%	'
Fixed maturities	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	48,757.10	50,939.30
U.S. government and agencies	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	780.5	944.3
Non-U.S. governments	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	996.8	1,208.30
States and political subdivisions	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	3,658	3,178.80
Corporate debt securities	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	31,919	34,325.40
Residential mortgage-backed pass-through securities	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	2,845.20	3,226.70
Commercial mortgage-backed securities	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	4,026.40	3,897.40
Collateralized debt obligations	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	363.4	379.2
Other debt obligations	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	4,167.80	3,779.20
Equity securities	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	110.5	136.5
Recurring Fair Value Measurements | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Derivative assets	665.1	1,016.70
Other investments	361.1	272.1
Cash equivalents	1,459	1,772.60
Sub-total excluding separate account assets	52,632.80	55,016.70
Separate account assets	130,018.40	81,653.80
Total assets	182,651.20	136,670.50
Investment-type insurance contracts	-6.9	-170.5
Derivative liabilities	-1,024.60	-1,205.10
Other liabilities	-322.1	-237.4
Total liabilities	-1,353.60	-1,613
Net assets (liabilities)	181,297.60	135,057.50
Recurring Fair Value Measurements | Fair value hierarchy Level 1	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Other investments	6.8	64.1
Cash equivalents	'	561.4
Sub-total excluding separate account assets	599.6	1,078.50
Separate account assets	67,215.10	54,010.10
Total assets	67,814.70	55,088.60
Net assets (liabilities)	67,814.70	55,088.60
Recurring Fair Value Measurements | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Derivative assets	590.9	941.6
Other investments	211.4	94.1
Cash equivalents	1,459	1,211.20
Sub-total excluding separate account assets	51,292.50	53,254.10
Separate account assets	57,538.10	23,027.70
Total assets	108,830.60	76,281.80
Derivative liabilities	-985	-1,102.50
Other liabilities	-248.2	-197.8
Total liabilities	-1,233.20	-1,300.30
Net assets (liabilities)	107,597.40	74,981.50
Recurring Fair Value Measurements | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Derivative assets	74.2	75.1
Other investments	142.9	113.9
Sub-total excluding separate account assets	740.7	684.1
Separate account assets	5,265.20	4,616
Total assets	6,005.90	5,300.10
Investment-type insurance contracts	-6.9	-170.5
Derivative liabilities	-39.6	-102.6
Other liabilities	-73.9	-39.6
Total liabilities	-120.4	-312.7
Net assets (liabilities)	5,885.50	4,987.40
Recurring Fair Value Measurements | Fixed maturities | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	48,757.10	50,939.30
Trading	563.1	626.7
Recurring Fair Value Measurements | Fixed maturities | Fair value hierarchy Level 1	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	449.6	289.4
Trading	'	9.4
Recurring Fair Value Measurements | Fixed maturities | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	47,970.70	50,336.90
Trading	393.2	450.5
Recurring Fair Value Measurements | Fixed maturities | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	336.8	313
Trading	169.9	166.8
Recurring Fair Value Measurements | U.S. government and agencies | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	780.5	944.3
Recurring Fair Value Measurements | U.S. government and agencies | Fair value hierarchy Level 1	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	409.3	203.5
Recurring Fair Value Measurements | U.S. government and agencies | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	371.2	740.8
Recurring Fair Value Measurements | Non-U.S. governments | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	996.8	1,208.30
Recurring Fair Value Measurements | Non-U.S. governments | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	949.3	1,164
Recurring Fair Value Measurements | Non-U.S. governments | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	47.5	44.3
Recurring Fair Value Measurements | States and political subdivisions | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	3,658	3,178.80
Recurring Fair Value Measurements | States and political subdivisions | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	3,656.20	3,176.90
Recurring Fair Value Measurements | States and political subdivisions | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	1.8	1.9
Recurring Fair Value Measurements | Corporate debt securities | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	31,919	34,325.40
Recurring Fair Value Measurements | Corporate debt securities | Fair value hierarchy Level 1	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	40.3	85.9
Recurring Fair Value Measurements | Corporate debt securities | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	31,714.70	34,065
Recurring Fair Value Measurements | Corporate debt securities | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	164	174.5
Recurring Fair Value Measurements | Residential mortgage-backed pass-through securities | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	2,845.20	3,226.70
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	'	'
Available-for-sale	2,845.20	3,226.70
Recurring Fair Value Measurements | Commercial mortgage-backed securities | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	4,026.40	3,897.40
Recurring Fair Value Measurements | Commercial mortgage-backed securities | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	4,024.80	3,897.40
Recurring Fair Value Measurements | Commercial mortgage-backed securities | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	1.6	'
Recurring Fair Value Measurements | Collateralized debt obligations | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	363.4	379.2
Recurring Fair Value Measurements | Collateralized debt obligations | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	325.6	301.6
Recurring Fair Value Measurements | Collateralized debt obligations | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	37.8	77.6
Recurring Fair Value Measurements | Other debt obligations | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	4,167.80	3,779.20
Recurring Fair Value Measurements | Other debt obligations | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	4,083.70	3,764.50
Recurring Fair Value Measurements | Other debt obligations | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	84.1	14.7
Recurring Fair Value Measurements | Equity securities | Assets (liabilities) measured at fair value	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	110.5	136.5
Trading	716.9	252.8
Recurring Fair Value Measurements | Equity securities | Fair value hierarchy Level 1	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	38.1	54.4
Trading	105.1	99.8
Recurring Fair Value Measurements | Equity securities | Fair value hierarchy Level 2	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	55.5	66.8
Trading	611.8	153
Recurring Fair Value Measurements | Equity securities | Fair value hierarchy Level 3	'	'
Assets (liabilities) measured at fair value on a recurring basis	'	'
Available-for-sale	$16.90	$15.30

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (Recurring Fair Value Measurements, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale | Fixed maturities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	$313	$449.70	$790.90
Total realized/unrealized gains (losses) included in net income, assets	-11.7	-15	-33.8
Total realized/unrealized gains (losses) included in other comprehensive income, assets	13.5	25.5	-3
Net purchases, sales, issuances and settlements, assets	-40.7	-89.9	-85.2
Transfers into Level 3, assets	171.4	111.3	112.2
Transfers out of Level 3, assets	-108.7	-168.6	-331.4
Ending balance, assets	336.8	313	449.7
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	-10.8	-4.9	-15.3
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	96.7	47.8	26.1
Sales, assets	-84.6	-98.1	-41.9
Settlements, assets	-52.8	-39.6	-69.4
Net purchases, sales, issuances and settlements, assets	-40.7	-89.9	-85.2
Available-for-sale | Non-U.S. governments	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	44.3	22.9	24.5
Total realized/unrealized gains (losses) included in net income, assets	-0.1	-0.2	0.2
Total realized/unrealized gains (losses) included in other comprehensive income, assets	-0.9	-0.3	'
Net purchases, sales, issuances and settlements, assets	4.2	7.4	-1.8
Transfers into Level 3, assets	'	14.5	'
Ending balance, assets	47.5	44.3	22.9
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	-0.1	-0.1	0.1
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	9.3	13.5	3.6
Sales, assets	-3.9	-5	-5.4
Settlements, assets	-1.2	-1.1	'
Net purchases, sales, issuances and settlements, assets	4.2	7.4	-1.8
Available-for-sale | States and political subdivisions	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	1.9	'	'
Total realized/unrealized gains (losses) included in other comprehensive income, assets	'	0.2	'
Net purchases, sales, issuances and settlements, assets	-0.1	-0.1	'
Transfers into Level 3, assets	'	1.8	'
Ending balance, assets	1.8	1.9	'
Gross purchases, sales, issuances and settlements	'	'	'
Settlements, assets	-0.1	-0.1	'
Net purchases, sales, issuances and settlements, assets	-0.1	-0.1	'
Available-for-sale | Corporate debt securities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	174.5	297	552.1
Total realized/unrealized gains (losses) included in net income, assets	-13.4	-9.2	-10.8
Total realized/unrealized gains (losses) included in other comprehensive income, assets	4.5	19.9	-20.8
Net purchases, sales, issuances and settlements, assets	-23	-75.5	-42.7
Transfers into Level 3, assets	105.3	79.7	103.2
Transfers out of Level 3, assets	-83.9	-137.4	-284
Ending balance, assets	164	174.5	297
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	-10.4	-2.6	-6.1
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	32.6	29.2	21.2
Sales, assets	-33.3	-92	-25.6
Settlements, assets	-22.3	-12.7	-38.3
Net purchases, sales, issuances and settlements, assets	-23	-75.5	-42.7
Available-for-sale | Commercial mortgage-backed securities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	'	'	16.2
Total realized/unrealized gains (losses) included in net income, assets	'	'	-3.7
Total realized/unrealized gains (losses) included in other comprehensive income, assets	-0.1	'	5.1
Net purchases, sales, issuances and settlements, assets	-0.7	'	-10.5
Transfers into Level 3, assets	2.4	'	'
Transfers out of Level 3, assets	'	'	-7.1
Ending balance, assets	1.6	'	'
Gross purchases, sales, issuances and settlements	'	'	'
Sales, assets	'	'	-10.5
Settlements, assets	-0.7	'	'
Net purchases, sales, issuances and settlements, assets	-0.7	'	-10.5
Available-for-sale | Collateralized debt obligations	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	77.6	102.5	109.3
Total realized/unrealized gains (losses) included in net income, assets	2.1	-3.3	-19.6
Total realized/unrealized gains (losses) included in other comprehensive income, assets	7.2	5.1	13.8
Net purchases, sales, issuances and settlements, assets	-56	4.5	0.3
Transfers into Level 3, assets	31.7	'	'
Transfers out of Level 3, assets	-24.8	-31.2	-1.3
Ending balance, assets	37.8	77.6	102.5
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	'	'	-9.3
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	17	5.1	1.3
Sales, assets	-47.4	-1.1	-0.4
Settlements, assets	-25.6	0.5	-0.6
Net purchases, sales, issuances and settlements, assets	-56	4.5	0.3
Available-for-sale | Other debt obligations	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	14.7	27.3	88.8
Total realized/unrealized gains (losses) included in net income, assets	-0.3	-2.3	0.1
Total realized/unrealized gains (losses) included in other comprehensive income, assets	2.8	0.6	-1.1
Net purchases, sales, issuances and settlements, assets	34.9	-26.2	-30.5
Transfers into Level 3, assets	32	15.3	9
Transfers out of Level 3, assets	'	'	-39
Ending balance, assets	84.1	14.7	27.3
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	-0.3	-2.2	'
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	37.8	'	'
Settlements, assets	-2.9	-26.2	-30.5
Net purchases, sales, issuances and settlements, assets	34.9	-26.2	-30.5
Available-for-sale | Equity securities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	15.3	18	43.2
Total realized/unrealized gains (losses) included in net income, assets	-0.2	-0.3	-6.1
Total realized/unrealized gains (losses) included in other comprehensive income, assets	1.8	-2.4	12
Net purchases, sales, issuances and settlements, assets	'	'	-28
Transfers into Level 3, assets	'	'	13
Transfers out of Level 3, assets	'	'	-16.1
Ending balance, assets	16.9	15.3	18
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	-0.2	'	-4.5
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	'	'	0.3
Sales, assets	'	'	-28.3
Net purchases, sales, issuances and settlements, assets	'	'	-28
Trading | Fixed maturities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	166.8	220.8	269.1
Total realized/unrealized gains (losses) included in net income, assets	3	3.2	-16.6
Net purchases, sales, issuances and settlements, assets	0.1	-66.7	-27.2
Transfers into Level 3, assets	'	9.5	20.5
Transfers out of Level 3, assets	'	'	-25
Ending balance, assets	169.9	166.8	220.8
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	3.1	-4.4	-15.8
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	'	'	10
Sales, assets	'	-24.6	-8.7
Settlements, assets	0.1	-42.1	-28.5
Net purchases, sales, issuances and settlements, assets	0.1	-66.7	-27.2
Derivative assets	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	75.1	60.2	33.3
Total realized/unrealized gains (losses) included in net income, assets	-19.5	2.9	37.8
Total realized/unrealized gains (losses) included in other comprehensive income, assets	'	'	-0.1
Net purchases, sales, issuances and settlements, assets	18.6	12	-10.8
Ending balance, assets	74.2	75.1	60.2
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	-19.8	4.9	33.4
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	22.1	12.6	19
Sales, assets	-3.5	-0.6	-29.8
Net purchases, sales, issuances and settlements, assets	18.6	12	-10.8
Other investments	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	113.9	97.5	128.3
Total realized/unrealized gains (losses) included in net income, assets	11.2	2.1	-2.5
Net purchases, sales, issuances and settlements, assets	17.8	14.3	-28.3
Ending balance, assets	142.9	113.9	97.5
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	11.2	2.2	-2.6
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	30.2	34	'
Settlements, assets	-12.4	-19.7	-28.3
Net purchases, sales, issuances and settlements, assets	17.8	14.3	-28.3
Separate account assets	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, assets	4,616	4,198.20	3,771.50
Total realized/unrealized gains (losses) included in net income, assets	574.9	421.3	406.6
Total realized/unrealized gains (losses) included in other comprehensive income, assets	-0.1	0.4	'
Net purchases, sales, issuances and settlements, assets	68.2	-3.6	88.9
Transfers into Level 3, assets	12.7	1.6	13.5
Transfers out of Level 3, assets	-6.5	-1.9	-82.3
Ending balance, assets	5,265.20	4,616	4,198.20
Changes in unrealized gains (losses) included in net income relating to positions still held, assets	545.8	412.8	400.9
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, assets	418.4	342.2	342.7
Sales, assets	-300.8	-310.6	-191.8
Issuances, assets	-21.8	-208.4	'
Settlements, assets	-27.6	173.2	-62
Net purchases, sales, issuances and settlements, assets	68.2	-3.6	88.9
Investment-type insurance contracts	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, liabilities	-170.5	-195.8	-6.6
Total realized/unrealized gains (losses) included in net income, liabilities	147.3	38.3	-206.3
Total realized/unrealized gains (losses) included in other comprehensive income, liabilities	'	-0.1	'
Net purchases, sales, issuances and settlements, liabilities	16.3	-12.9	17.1
Ending balance, liabilities	-6.9	-170.5	-195.8
Changes in unrealized gains (losses) included in net income relating to positions still held, liabilities	145	35.3	-206.6
Gross purchases, sales, issuances and settlements	'	'	'
Issuances, liabilities	11	-16.6	9.2
Settlements, liabilities	5.3	3.7	7.9
Net purchases, sales, issuances and settlements, liabilities	16.3	-12.9	17.1
Derivative liabilities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, liabilities	-102.6	-177.1	-181.5
Total realized/unrealized gains (losses) included in net income, liabilities	55	39.8	-11.4
Total realized/unrealized gains (losses) included in other comprehensive income, liabilities	-0.1	1.3	0.2
Net purchases, sales, issuances and settlements, liabilities	8.1	33.4	15.6
Ending balance, liabilities	-39.6	-102.6	-177.1
Changes in unrealized gains (losses) included in net income relating to positions still held, liabilities	53.9	38.6	-8.6
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, liabilities	-3.4	-8.9	-12.1
Sales, liabilities	11.5	42.3	27.7
Net purchases, sales, issuances and settlements, liabilities	8.1	33.4	15.6
Other liabilities	'	'	'
Changes in Level 3 fair value measurements rollforward, assets and liabilities	'	'	'
Beginning balance, liabilities	-39.6	-24.2	-156.8
Total realized/unrealized gains (losses) included in net income, liabilities	-34.3	-23.5	-1.2
Total realized/unrealized gains (losses) included in other comprehensive income, liabilities	'	'	13.4
Net purchases, sales, issuances and settlements, liabilities	'	8.1	-15.9
Transfers out of Level 3, liabilities	'	'	136.3
Ending balance, liabilities	-73.9	-39.6	-24.2
Changes in unrealized gains (losses) included in net income relating to positions still held, liabilities	-34.3	-20.2	-1.1
Gross purchases, sales, issuances and settlements	'	'	'
Purchases, liabilities	'	'	-2.1
Sales, liabilities	'	8.1	'
Settlements, liabilities	'	'	-13.8
Net purchases, sales, issuances and settlements, liabilities	'	$8.10	($15.90)

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 3) (Recurring Fair Value Measurements, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale | Fixed maturities	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	$171.40	$111.30	'
Transfers out of Level 3 into Level 2	108.7	168.6	'
Available-for-sale | Non-U.S. governments	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	'	14.5	'
Available-for-sale | States and political subdivisions	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	'	1.8	'
Available-for-sale | Corporate debt securities	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	105.3	79.7	'
Transfers out of Level 3 into Level 2	83.9	137.4	'
Available-for-sale | Collateralized debt obligations	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	31.7	'	'
Transfers out of Level 3 into Level 2	24.8	31.2	'
Available-for-sale | Other debt obligations	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	32	15.3	'
Available-for-sale | Commercial mortgage-backed securities	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	2.4	'	'
Separate account assets	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 1 into Level 2	253.9	3,255.70	3,595.90
Transfers out of Level 1 into Level 3	0.1	0.3	'
Transfers out of Level 2 into Level 1	15.5	205.5	2,796.10
Transfers out of Level 2 into Level 3	12.6	1.3	'
Transfers out of Level 3 into Level 2	6.5	1.9	'
Trading | Fixed maturities	'	'	'
Fair Value Hierarchy Levels Transfers	'	'	'
Transfers out of Level 2 into Level 3	'	$9.50	'

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details 4) (Recurring Fair Value Measurements, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets (liabilities) measured at fair value	'	'
Unobservable inputs	'	'
Assets measured at fair value	182,651.20	136,670.50
Liabilities measured at fair value	-1,353.60	-1,613
Assets (liabilities) measured at fair value | Available-for-sale | Non-U.S. governments	'	'
Unobservable inputs	'	'
Assets measured at fair value	11.7	12.9
Assets (liabilities) measured at fair value | Available-for-sale | Corporate debt securities	'	'
Unobservable inputs	'	'
Assets measured at fair value	70.1	66.6
Assets (liabilities) measured at fair value | Available-for-sale | Commercial mortgage-backed securities	'	'
Unobservable inputs	'	'
Assets measured at fair value	1.6	'
Assets (liabilities) measured at fair value | Available-for-sale | Collateralized debt obligations	'	'
Unobservable inputs	'	'
Assets measured at fair value	13.6	38.2
Assets (liabilities) measured at fair value | Available-for-sale | Other debt obligations	'	'
Unobservable inputs	'	'
Assets measured at fair value	33.6	14.7
Assets (liabilities) measured at fair value | Trading | Fixed maturities	'	'
Unobservable inputs	'	'
Assets measured at fair value	36.2	35.9
Assets (liabilities) measured at fair value | Trading | Collateralized private investment vehicle | Fixed maturities	'	'
Unobservable inputs	'	'
Assets measured at fair value	110.4	110.4
Assets (liabilities) measured at fair value | Other investments | Discounted cash flow, commercial mortgage loans of consolidated VIEs	'	'
Unobservable inputs	'	'
Assets measured at fair value	68.1	80.3
Assets (liabilities) measured at fair value | Other investments | Discounted cash flow, equity method real estate investment	'	'
Unobservable inputs	'	'
Assets measured at fair value	74.8	33.6
Assets (liabilities) measured at fair value | Separate account assets	'	'
Unobservable inputs	'	'
Assets measured at fair value	5,090.40	4,449
Assets (liabilities) measured at fair value | Investment-type insurance contracts	'	'
Unobservable inputs	'	'
Liabilities measured at fair value	-6.9	-170.5
Assets (liabilities) measured at fair value | Derivative liabilities	'	'
Unobservable inputs	'	'
Liabilities measured at fair value	-19.9	-65.1
Assets (liabilities) measured at fair value | Other liabilities	'	'
Unobservable inputs	'	'
Liabilities measured at fair value	-73.9	-39.6
Fair value hierarchy Level 3	'	'
Unobservable inputs	'	'
Assets measured at fair value	6,005.90	5,300.10
Liabilities measured at fair value	-120.4	-312.7
Fair value hierarchy Level 3 | Available-for-sale | Non-U.S. governments | Discounted cash flow | Input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	2.00%	1.60%
Illiquidity premium (as a percent)	0.50%	0.50%
Fair value hierarchy Level 3 | Available-for-sale | Non-U.S. governments | Discounted cash flow | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	2.00%	1.60%
Illiquidity premium (as a percent)	0.50%	0.50%
Fair value hierarchy Level 3 | Available-for-sale | Corporate debt securities | Discounted cash flow | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	1.90%	1.70%
Illiquidity premium (as a percent)	0.00%	0.00%
Earnings before interest, taxes, depreciation and amortization multiple	0	0
Comparability adjustment (as a percent)	0.00%	'
Probability of default (as a percent)	0.00%	0.00%
Potential loss severity (as a percent)	0.00%	0.00%
Fair value hierarchy Level 3 | Available-for-sale | Corporate debt securities | Discounted cash flow | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	7.70%	29.00%
Illiquidity premium (as a percent)	0.25%	1.00%
Earnings before interest, taxes, depreciation and amortization multiple	4.5	3.5
Comparability adjustment (as a percent)	1.25%	'
Probability of default (as a percent)	100.00%	100.00%
Potential loss severity (as a percent)	16.00%	30.00%
Fair value hierarchy Level 3 | Available-for-sale | Corporate debt securities | Discounted cash flow | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	4.40%	8.40%
Illiquidity premium (as a percent)	0.15%	0.39%
Earnings before interest, taxes, depreciation and amortization multiple	0.2	0.2
Comparability adjustment (as a percent)	0.43%	'
Probability of default (as a percent)	5.40%	6.40%
Potential loss severity (as a percent)	0.90%	1.90%
Fair value hierarchy Level 3 | Available-for-sale | Commercial mortgage-backed securities | Discounted cash flow | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	1.50%	'
Fair value hierarchy Level 3 | Available-for-sale | Commercial mortgage-backed securities | Discounted cash flow | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	4.50%	'
Fair value hierarchy Level 3 | Available-for-sale | Commercial mortgage-backed securities | Discounted cash flow | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	0.00%	'
Fair value hierarchy Level 3 | Available-for-sale | Collateralized debt obligations | Discounted cash flow | Input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	1.50%	'
Illiquidity premium (as a percent)	4.00%	'
Fair value hierarchy Level 3 | Available-for-sale | Collateralized debt obligations | Discounted cash flow | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	'	1.00%
Illiquidity premium (as a percent)	'	4.00%
Fair value hierarchy Level 3 | Available-for-sale | Collateralized debt obligations | Discounted cash flow | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	'	19.80%
Illiquidity premium (as a percent)	'	10.00%
Fair value hierarchy Level 3 | Available-for-sale | Collateralized debt obligations | Discounted cash flow | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	1.50%	13.30%
Illiquidity premium (as a percent)	4.00%	7.91%
Fair value hierarchy Level 3 | Available-for-sale | Other debt obligations | Discounted cash flow | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	2.00%	6.50%
Illiquidity premium (as a percent)	0.00%	0.00%
Fair value hierarchy Level 3 | Available-for-sale | Other debt obligations | Discounted cash flow | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	15.00%	20.00%
Illiquidity premium (as a percent)	0.50%	0.50%
Fair value hierarchy Level 3 | Available-for-sale | Other debt obligations | Discounted cash flow | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	6.70%	11.80%
Illiquidity premium (as a percent)	0.11%	0.30%
Fair value hierarchy Level 3 | Trading | Fixed maturities | Discounted cash flow | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	1.60%	1.20%
Illiquidity premium (as a percent)	0.00%	0.00%
Fair value hierarchy Level 3 | Trading | Fixed maturities | Discounted cash flow | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	83.00%	60.50%
Illiquidity premium (as a percent)	14.00%	14.00%
Fair value hierarchy Level 3 | Trading | Fixed maturities | Discounted cash flow | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	3.40%	4.10%
Illiquidity premium (as a percent)	3.70%	3.90%
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, commercial mortgage loans of consolidated VIEs | Input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	4.80%	3.50%
Illiquidity premium (as a percent)	0.94%	2.87%
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, commercial mortgage loans of consolidated VIEs | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	4.80%	3.50%
Illiquidity premium (as a percent)	0.94%	2.87%
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment | Input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	'	9.30%
Terminal capitalization rate (as a percent)	'	5.50%
Average market rent growth rate (as a percent)	'	3.60%
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	7.80%	'
Terminal capitalization rate (as a percent)	5.50%	'
Average market rent growth rate (as a percent)	3.50%	'
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	8.10%	'
Terminal capitalization rate (as a percent)	6.80%	'
Average market rent growth rate (as a percent)	3.60%	'
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	7.90%	9.30%
Terminal capitalization rate (as a percent)	6.10%	5.50%
Average market rent growth rate (as a percent)	3.60%	3.60%
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment debt | Input	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	'	49.40%
Credit spread rate (as a percent)	'	3.30%
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment debt | Minimum	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	40.50%	'
Credit spread rate (as a percent)	1.50%	'
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment debt | Maximum	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	61.00%	'
Credit spread rate (as a percent)	2.00%	'
Fair value hierarchy Level 3 | Other investments | Discounted cash flow, equity method real estate investment debt | Weighted average input	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	50.70%	49.40%
Credit spread rate (as a percent)	1.80%	3.30%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	0.60%	0.80%
Illiquidity premium (as a percent)	0.00%	0.00%
Credit spread rate (as a percent)	0.32%	0.44%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	5.60%	10.40%
Illiquidity premium (as a percent)	0.60%	0.50%
Credit spread rate (as a percent)	4.40%	9.75%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, mortgage loans | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	3.30%	3.30%
Illiquidity premium (as a percent)	0.12%	0.20%
Credit spread rate (as a percent)	2.14%	2.86%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Minimum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	6.00%	6.50%
Terminal capitalization rate (as a percent)	4.50%	4.80%
Average market rent growth rate (as a percent)	2.40%	2.30%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Maximum	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	16.00%	16.00%
Terminal capitalization rate (as a percent)	9.00%	9.00%
Average market rent growth rate (as a percent)	4.70%	5.50%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Weighted average input	'	'
Unobservable inputs	'	'
Discount rate (as a percent)	7.60%	8.30%
Terminal capitalization rate (as a percent)	6.60%	7.20%
Average market rent growth rate (as a percent)	3.00%	3.30%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Minimum	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	11.00%	17.00%
Credit spread rate (as a percent)	1.50%	1.60%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Maximum	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	55.90%	86.00%
Credit spread rate (as a percent)	5.20%	5.30%
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Weighted average input	'	'
Unobservable inputs	'	'
Loan to value (as a percent)	50.30%	54.80%
Credit spread rate (as a percent)	3.30%	3.50%
Fair value hierarchy Level 3 | Investment-type insurance contracts | Discounted cash flow | Minimum	'	'
Unobservable inputs	'	'
Long duration interest rate (as a percent)	3.80%	2.60%
Long-term equity market volatility (as a percent)	15.00%	16.10%
Non-performance risk (as a percent)	0.20%	0.30%
Lapse rate (as a percent)	0.50%	0.50%
Period of swap rate used for calculating long duration interest rate	'20 years	'20 years
Fair value hierarchy Level 3 | Investment-type insurance contracts | Discounted cash flow | Maximum	'	'
Unobservable inputs	'	'
Long duration interest rate (as a percent)	3.90%	2.80%
Long-term equity market volatility (as a percent)	40.10%	38.30%
Non-performance risk (as a percent)	1.20%	1.60%
Lapse rate (as a percent)	14.60%	14.60%
Period of swap rate used for calculating long duration interest rate	'30 years	'30 years

Fair_Value_Measurements_Detail4

Fair Value Measurements (Details 5) (Nonrecurring Fair Value Measurements, Fair value hierarchy Level 3, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Mortgage loans	'	'	'
Assets and liabilities measured at fair value on a nonrecurring basis	'	'	'
Fair value of assets measured on nonrecurring basis	$153.10	$173.80	$206
Net (gain) loss due to change in fair value of assets measured on nonrecurring basis	27.5	12.3	27.7
Mortgage loans | Minimum	'	'	'
Assets and liabilities measured at fair value on a nonrecurring basis	'	'	'
Discount rate (as a percent)	8.00%	8.00%	'
Terminal capitalization rate (as a percent)	7.30%	6.30%	'
Average market rent growth rate (as a percent)	1.00%	3.00%	'
Mortgage loans | Maximum	'	'	'
Assets and liabilities measured at fair value on a nonrecurring basis	'	'	'
Discount rate (as a percent)	20.00%	20.00%	'
Terminal capitalization rate (as a percent)	10.50%	10.50%	'
Average market rent growth rate (as a percent)	10.90%	8.00%	'
Mortgage servicing rights	'	'	'
Assets and liabilities measured at fair value on a nonrecurring basis	'	'	'
Fair value of assets measured on nonrecurring basis	7.3	7	4.4
Net (gain) loss due to change in fair value of assets measured on nonrecurring basis	-1.3	-0.4	1.1
Mortgage servicing rights | Input	'	'	'
Assets and liabilities measured at fair value on a nonrecurring basis	'	'	'
Discount rate (as a percent)	4.30%	3.10%	'
Real estate	'	'	'
Assets and liabilities measured at fair value on a nonrecurring basis	'	'	'
Fair value of assets measured on nonrecurring basis	'	5	3.9
Net (gain) loss due to change in fair value of assets measured on nonrecurring basis	'	$0.10	$0.60

Fair_Value_Measurements_Detail5

Fair Value Measurements (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	item	item	item
Commercial Mortgage Loans of Consolidated VIEs	'	'	'
Fair Value Option, Quantitative Disclosures	'	'	'
Fair value of assets for which fair value option was elected	$68.10	$80.30	'
Contractual principal amounts of assets for which the fair value option was elected	64	76.4	'
Pre-tax gain (loss) due to change in fair value of assets and liabilities for which the fair value option was elected	0.2	2.6	-2.6
Credit risk portion of pre-tax gain (loss) due to change in fair value of assets for which the fair value option was elected	0	0	0
Number of loans which are more than 90 days past due or in nonaccrual status	0	0	0
Interest income	5.7	6.9	8.6
Obligations of Consolidated VIEs	'	'	'
Fair Value Option, Quantitative Disclosures	'	'	'
Fair value of liabilities for which the fair value option was elected	104.9	85	'
Aggregate unpaid principal amounts of obligations for which the fair value option was elected	174.4	186.8	'
Pre-tax gain (loss) due to change in fair value of assets and liabilities for which the fair value option was elected	-32.8	-37.7	1.2
Credit risk portion of pre-tax gain (loss) due to change in fair value of liabilities for which the fair value option was elected	-34.3	-37.4	-1.1
Interest expense	3.6	5.3	6.7
Equity Method Investment	'	'	'
Fair Value Option, Quantitative Disclosures	'	'	'
Fair value of assets for which fair value option was elected	74.8	33.6	'
Pre-tax gain (loss) due to change in fair value of assets and liabilities for which the fair value option was elected	$11	($0.40)	'

Fair_Value_Measurements_Detail6

Fair Value Measurements (Details 7) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Assets (liabilities)	'	'
Mortgage loans	$11,533.60	$11,519.70
Policy loans	859.7	864.9
Short-term debt	-150.6	-40.8
Long-term debt	-2,601.40	-2,671.30
Fair value hierarchy Level 1	'	'
Assets (liabilities)	'	'
Cash and cash equivalents not required to be reported at fair value	912.8	2,364.60
Bank deposits	-1,252.20	-1,404.40
Cash collateral payable	-32.5	-205.6
Fair value hierarchy Level 2	'	'
Assets (liabilities)	'	'
Other investments	140.9	195.3
Cash and cash equivalents not required to be reported at fair value	'	40
Investment-type insurance contracts	-5,902.20	-7,367.40
Short-term debt	-150.6	-40.8
Long-term debt	-2,639	-2,921.70
Bank deposits	-698.9	-773.3
Fair value hierarchy Level 3	'	'
Assets (liabilities)	'	'
Mortgage loans	11,773.50	12,163.70
Policy loans	963.3	1,056.80
Other investments	33.8	85.2
Investment-type insurance contracts	-24,190.90	-25,164.20
Long-term debt	-53.1	-29.7
Separate account liabilities	-118,059.70	-72,173.80
Carrying amount	'	'
Assets (liabilities)	'	'
Mortgage loans	11,533.60	11,519.70
Policy loans	859.7	864.9
Other investments	174	280.1
Cash and cash equivalents not required to be reported at fair value	912.8	2,404.60
Investment-type insurance contracts	-29,909.60	-31,953.10
Short-term debt	-150.6	-40.8
Long-term debt	-2,601.40	-2,671.30
Separate account liabilities	-119,500.70	-73,096
Bank deposits	-1,949	-2,174.70
Cash collateral payable	-32.5	-205.6
Fair Value	'	'
Assets (liabilities)	'	'
Mortgage loans	11,773.50	12,163.70
Policy loans	963.3	1,056.80
Other investments	174.7	280.5
Cash and cash equivalents not required to be reported at fair value	912.8	2,404.60
Investment-type insurance contracts	-30,093.10	-32,531.60
Short-term debt	-150.6	-40.8
Long-term debt	-2,692.10	-2,951.40
Separate account liabilities	-118,059.70	-72,173.80
Bank deposits	-1,951.10	-2,177.70
Cash collateral payable	($32.50)	($205.60)

Statutory_Insurance_Financial_2

Statutory Insurance Financial Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statutory disclosures	'	'	'
Impact of prescribed and permitted practices on statutory net income	$9	'	'
Statutory reserves assumed by affiliated reinsurance subsidiaries	2,765.70	'	'
Admitted assets under prescribed and permitted statutory accounting practices	1,059	'	'
Statutory net income	607.9	576.1	326.8
Statutory capital and surplus	$4,142.20	$3,944.30	$4,218.20

Segment_Information_Details

Segment Information (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Segment Information: Assets	'	'
Total assets	$208,191.40	$161,830.20
Retirement and Investor Services	'	'
Segment Information: Assets	'	'
Total assets	128,736.70	117,399.50
Principal Global Investors	'	'
Segment Information: Assets	'	'
Total assets	1,312.10	1,282.20
Principal International	'	'
Segment Information: Assets	'	'
Total assets	54,243.60	19,170.90
U.S. Insurance Solutions	'	'
Segment Information: Assets	'	'
Total assets	20,033.60	19,017.20
Corporate	'	'
Segment Information: Assets	'	'
Total assets	$3,865.40	$4,960.40

Segment_Information_Details_2

Segment Information (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	$9,607.40	$9,175.40	$8,281
Net realized capital gains (losses), net of related revenue adjustments	'	'	'	'	'	'	'	'	-320	14.7	-221.5
Exited group medical insurance business	'	'	'	'	'	'	'	'	2.1	25	606.3
Assumption change within Individual Life business	'	'	'	'	'	'	'	'	'	'	4.9
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Operating earnings (loss)	'	'	'	'	'	'	'	'	1,059.90	808.8	829.3
Net realized capital gains (losses), as adjusted	'	'	'	'	'	'	'	'	-179.1	39	-141.7
Other after-tax adjustments	'	'	'	'	'	'	'	'	-1.1	-74.2	-82.3
Net income (loss) available to common stockholders	233.4	245.7	222.3	178.3	214.9	187.2	167.6	203.9	879.7	773.6	605.3
One-time costs associated with early extinguishment of long-term debt	'	'	'	'	'	'	'	'	'	-24.8	'
Impact of court ruling on uncertain tax positions	'	'	'	'	'	'	'	'	'	'	-68.9
Impact of assumption change within Individual Life business	'	'	'	'	'	'	'	'	'	'	-34.5
Contribution to The Principal Financial Group Foundation, Inc.	'	'	'	'	'	'	'	'	'	-39.8	-19.5
Estimated obligation associated with Executive Life of New York's liquidation petition	'	'	'	'	'	'	'	'	'	'	-10.3
After-tax gains (losses) associated with exited group medical insurance business that does not qualify for discontinued operations	'	'	'	'	'	'	'	'	-1.1	-9.6	50.9
Aggregate Segments	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	9,607.40	9,175.40	8,281
Operating earnings (loss)	'	'	'	'	'	'	'	'	1,059.90	808.8	829.3
Retirement and Investor Services	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	4,847.60	4,834.90	4,075
Operating earnings (loss)	'	'	'	'	'	'	'	'	694.4	575.1	562.9
Principal Global Investors	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	719.2	591.2	546.3
Operating earnings (loss)	'	'	'	'	'	'	'	'	102.6	81.2	74
Principal International	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,150	942.7	909
Operating earnings (loss)	'	'	'	'	'	'	'	'	215.2	154.1	135
U.S. Insurance Solutions	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	3,106.40	2,994.70	2,939.90
Operating earnings (loss)	'	'	'	'	'	'	'	'	196.6	138.2	204.3
Corporate	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	-215.8	-188.1	-189.2
Operating earnings (loss)	'	'	'	'	'	'	'	'	($148.90)	($139.80)	($146.90)

Segment_Information_Details_3

Segment Information (Details 3) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Information: Net realized capital gains (losses), as adjusted	'	'	'	'	'	'	'
Net realized capital gains (losses)	$32.90	$87.70	$0.20	($6.70)	($225.20)	$114.10	($122.30)
Certain derivative and hedging-related adjustments	'	'	'	'	-93.9	-98.9	-98.8
Certain market value adjustments to fee revenues	'	'	'	'	'	-0.3	-0.1
Recognition of front-end fee revenues	'	'	'	'	-0.9	-0.2	-0.3
Net realized capital gains (losses), net of related revenue adjustments	'	'	'	'	-320	14.7	-221.5
Amortization of deferred acquisition costs and other actuarial balances	'	'	'	'	47.1	36.6	-21.5
Capital (gains) losses distributed	'	'	'	'	-25.8	-12.2	-3.1
Certain market value adjustments of embedded derivatives	'	'	'	'	18.4	-0.6	65.6
Net realized capital (gains) losses associated with exited group medical insurance business	'	'	'	'	'	0.2	-0.2
Noncontrolling interest capital (gains) losses	'	'	'	'	-0.2	-8.3	-31.6
Tax expense/benefit related to net realized capital gains (losses), as adjusted	'	'	'	'	101.4	8.6	70.6
Net realized capital gains (losses), as adjusted	'	'	'	'	($179.10)	$39	($141.70)

Segment_Information_Details_4

Segment Information (Details 4) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	$289.90	$185.80	$224.20
Tax expense/benefit related to net realized capital gains (losses), as adjusted	'	'	'	'	-101.4	-8.6	-70.6
Tax expense (benefit) related to other after-tax adjustments	'	'	'	'	-0.6	-42.6	44.7
Income taxes (benefits)	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Aggregate Segments	'	'	'	'	'	'	'
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	289.9	185.8	224.2
Retirement and Investor Services	'	'	'	'	'	'	'
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	195.6	150	163.9
Principal Global Investors	'	'	'	'	'	'	'
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	55.5	43.5	41
Principal International	'	'	'	'	'	'	'
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	28	0.6	-3.1
U.S. Insurance Solutions	'	'	'	'	'	'	'
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	94	61.3	95.3
Corporate	'	'	'	'	'	'	'
Segment Information: Income tax expense (benefit)	'	'	'	'	'	'	'
Total segment income tax expense (benefit) from operating earnings (loss)	'	'	'	'	($83.20)	($69.60)	($72.90)

Segment_Information_Details_5

Segment Information (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	$108.10	$80.90	$72.40
Depreciation and amortization expense related to other after-tax adjustments	1.4	6.1	6.1
Depreciation and amortization expense	109.5	87	78.5
Aggregate Segments	'	'	'
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	108.1	80.9	72.4
Retirement and Investor Services	'	'	'
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	26.7	26.3	24.7
Principal Global Investors	'	'	'
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	11.8	13.3	11.3
Principal International	'	'	'
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	47.8	18.9	14.8
U.S. Insurance Solutions	'	'	'
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	17.2	17	16.6
Corporate	'	'	'
Segment Information: Depreciation and amortization expense	'	'	'
Total segment depreciation and amortization expense	$4.60	$5.40	$5

Segment_Information_Details_6

Segment Information (Details 6) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	$9,607.40	$9,175.40	$8,281
Net realized capital gains (losses), net of related revenue adjustments	'	'	'	'	'	'	'	'	-320	14.7	-221.5
Exited group medical insurance business	'	'	'	'	'	'	'	'	2.1	25	606.3
Assumption change within Individual Life business	'	'	'	'	'	'	'	'	'	'	4.9
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Aggregate Segments	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	9,607.40	9,175.40	8,281
Retirement and Investor Services	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	4,847.60	4,834.90	4,075
Retirement and Investor Services | Total Accumulation	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	3,551.40	3,120.30	3,006.30
Retirement and Investor Services | Full service accumulation	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,470.70	1,357	1,338
Retirement and Investor Services | Principal Funds	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	765.8	619.6	560.4
Retirement and Investor Services | Individual annuities	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,366.50	1,162.40	1,119.20
Retirement and Investor Services | Bank and trust services	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	95.2	101.6	100.5
Retirement and Investor Services | Accumulation Eliminations	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	-146.8	-120.3	-111.8
Retirement and Investor Services | Total Guaranteed	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,296.20	1,714.60	1,068.70
Retirement and Investor Services | Investment only	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	341	431.6	508
Retirement and Investor Services | Full service payout	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	955.2	1,283	560.7
Principal Global Investors	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	719.2	591.2	546.3
Inter-segment revenues	'	'	'	'	'	'	'	'	243.7	217.6	212.2
Principal International	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,150	942.7	909
U.S. Insurance Solutions	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	3,106.40	2,994.70	2,939.90
U.S. Insurance Solutions | Individual life insurance	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,483	1,423.30	1,432
U.S. Insurance Solutions | Specialty benefits insurance	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	1,623.60	1,571.40	1,507.90
U.S. Insurance Solutions | U.S. Insurance Solutions Eliminations	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	-0.2	'	'
Corporate	'	'	'	'	'	'	'	'	'	'	'
Operating Revenues for Products and Services	'	'	'	'	'	'	'	'	'	'	'
Operating revenues	'	'	'	'	'	'	'	'	($215.80)	($188.10)	($189.20)

StockBased_Compensation_Plans_1

Stock-Based Compensation Plans (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	17-May-05
	Stock-Based Comp Plans	Stock-Based Comp Plans	Stock-Based Comp Plans	Amended and Restated 2010 Stock Incentive Plan and 2005 Directors Stock Plan	Stock Incentive Plan, Directors Stock Plan and Long-Term Performance Plan
Stock-Based Compensation Plans - Disclosures	'	'	'	'	'
Number of shares that will be granted	'	'	'	'	0
Maximum number of new shares of common stock available for grant (in shares)	'	'	'	6,500,000	'
Compensation cost	$65.20	$53.70	$46.30	'	'
Related income tax benefit	20	17.7	15.8	'	'
Capitalized as part of an asset	$2.60	$2.30	$2.20	'	'

StockBased_Compensation_Plans_2

Stock-Based Compensation Plans (Details 2) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan	'	'	'
Stock-Based Compensation Plans - Disclosures	'	'	'
Option expiration period	'10 years	'	'
Amended and Restated 2010 Stock Incentive Plan	'	'	'
Change in options outstanding	'	'	'
Options granted (in shares)	0.8	0.8	0.5
Directors Stock Plan	'	'	'
Stock-Based Compensation Plans - Disclosures	'	'	'
Contractual term of options granted	'the earlier of five years from the date the participant ceases to provide service or the tenth anniversary of the date the option was granted	'	'
Number of installments in which options become exercisable	4	'	'
Installment periods over which options become exercisable after grant date	'three, six and nine months anniversaries of the grant date, and on the date that the Director's full term of office expires	'	'
Change in options outstanding	'	'	'
Options granted (in shares)	0	0	0
Nonqualified Stock Options	'	'	'
Change in options outstanding	'	'	'
Options outstanding at beginning of period (in shares)	12.2	'	'
Options granted (in shares)	0.8	'	'
Options exercised (in shares)	3.3	'	'
Options expired (in shares)	0.1	'	'
Options outstanding at end of period (in shares)	9.6	12.2	'
Options vested or expected to vest at end of period (in shares)	9.6	'	'
Options exercisable at end of period (in shares)	8.1	'	'
Options outstanding at beginning of period weighted-average exercise price (in dollars per share)	39.61	'	'
Options granted weighted-average exercise price (in dollars per share)	30.7	'	'
Options exercised weighted-average exercise price (in dollars per share)	32.03	'	'
Options expired weighted-average exercise price (in dollars per share)	44.75	'	'
Options outstanding at end of period weighted-average exercise price (in dollars per share)	41.37	39.61	'
Options vested or expected to vest at end of period weighted-average exercise price (in dollars per share)	41.39	'	'
Options exercisable at end of period weighted-average exercise price (in dollars per share)	43.47	'	'
Options outstanding at end of period intrinsic value	112.2	'	'
Options vested or expected to vest at end of period intrinsic value	112	'	'
Options exercisable at end of period intrinsic value	83.3	'	'
Total intrinsic value of options exercised	30.7	5.7	4
Summary of weighted-average remaining contractual lives for stock options outstanding and range of exercise prices	'	'	'
Weighted-average remaining contractual life for stock options exercisable	'3 years 8 months 12 days	'	'
Assumptions used to estimate fair value of stock options granted during period	'	'	'
Weighted-average expected volatility (as a percent)	53.30%	70.00%	67.90%
Weighted-average expected term	'6 years 6 months	'6 years	'6 years
Weighted-average risk-free interest rate (as a percent)	1.10%	1.10%	2.50%
Weighted-average expected dividend yield (as a percent)	3.00%	2.55%	1.60%
Weighted-average estimated fair value of stock options granted (in dollars per share)	11.95	13.95	18.82
Other nonqualified stock option disclosures	'	'	'
Unrecognized compensation costs	2.7	'	'
Weighted-average service period over which unrecognized compensation costs will be recognized	'1 year 7 months 6 days	'	'
Cash received from stock options exercised	105.6	11.3	7.3
Tax benefits realized for the tax deductions from options exercised	10.6	1.6	1.4
Nonqualified Stock Options | 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)	11.07	'	'
Upper limit of exercise price range (in dollars per share)	21.69	'	'
Options outstanding at end of period (in shares)	1.1	'	'
Weighted-average remaining contractual life	'5 years 2 months 12 days	'	'
Nonqualified Stock Options | 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)	21.7	'	'
Upper limit of exercise price range (in dollars per share)	32.32	'	'
Options outstanding at end of period (in shares)	2.3	'	'
Weighted-average remaining contractual life	'8 years	'	'
Nonqualified Stock Options | 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)	32.33	'	'
Upper limit of exercise price range (in dollars per share)	42.95	'	'
Options outstanding at end of period (in shares)	1.5	'	'
Weighted-average remaining contractual life	'3 years	'	'
Nonqualified Stock Options | 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)	42.96	'	'
Upper limit of exercise price range (in dollars per share)	53.58	'	'
Options outstanding at end of period (in shares)	1.7	'	'
Weighted-average remaining contractual life	'2 years 2 months 12 days	'	'
Nonqualified Stock Options | 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)	53.59	'	'
Upper limit of exercise price range (in dollars per share)	64.22	'	'
Options outstanding at end of period (in shares)	3	'	'
Weighted-average remaining contractual life	'3 years 8 months 12 days	'	'
Nonqualified Stock Options | 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)	11.07	'	'
Upper limit of exercise price range (in dollars per share)	64.22	'	'
Options outstanding at end of period (in shares)	9.6	'	'
Weighted-average remaining contractual life	'4 years 6 months	'	'

StockBased_Compensation_Plans_3

Stock-Based Compensation Plans (Details 3) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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)	1	'	'
Awards or units granted (in shares)	0.3	0.4	0.3
Awards or units vested (in shares)	0.3	'	'
Awards or units outstanding at end of period (in shares)	1	1	'
Awards or units outstanding at beginning of period weighted-average grant-date fair value (in dollars per share)	$27.28	'	'
Awards or units granted weighted-average grant-date fair value (in dollars per share)	$30.70	$27.46	$34.26
Awards or units vested weighted-average grant-date fair value (in dollars per share)	$22.21	'	'
Awards or units outstanding at end of period weighted-average grant-date fair value (in dollars per share)	$30.30	$27.28	'
Other award and unit disclosures	'	'	'
Intrinsic value from awards or units vested	$10.90	$13	$0
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	5.2	'	'
Weighted-average service period over which unrecognized compensation costs will be recognized	'1 year 6 months	'	'
Tax benefits realized for the tax deductions from awards or units paid out	4.7	4.7	0
Restricted Stock Units	'	'	'
Change in nonvested units outstanding	'	'	'
Awards or units outstanding at beginning of period (in shares)	3.1	'	'
Awards or units granted (in shares)	1.3	1.2	0.9
Awards or units vested (in shares)	1.2	'	'
Awards or units canceled (in shares)	0.1	'	'
Awards or units outstanding at end of period (in shares)	3.1	3.1	'
Awards or units outstanding at beginning of period weighted-average grant-date fair value (in dollars per share)	$27.30	'	'
Awards or units granted weighted-average grant-date fair value (in dollars per share)	$31.02	$27.33	$33.35
Awards or units vested weighted-average grant-date fair value (in dollars per share)	$22.73	'	'
Awards or units canceled weighted-average grant-date fair value (in dollars per share)	$30.37	'	'
Awards or units outstanding at end of period weighted-average grant-date fair value (in dollars per share)	$30.46	$27.30	'
Other award and unit disclosures	'	'	'
Intrinsic value from awards or units vested	37.7	31.9	19.9
Unrecognized compensation costs	36.6	'	'
Weighted-average service period over which unrecognized compensation costs will be recognized	'1 year 9 months 18 days	'	'
Tax benefits realized for the tax deductions from awards or units paid out	$11.50	$11.10	$7.30
2005 Directors Stock Plan | Restricted Stock Units	'	'	'
Other award and unit disclosures	'	'	'
Vesting period	'1 year	'	'
Amended and Restated 2010 Stock Incentive Plan and Stock Incentive Plan | Restricted Stock Units	'	'	'
Other award and unit disclosures	'	'	'
Vesting period	'3 years	'	'

StockBased_Compensation_Plans_4

Stock-Based Compensation Plans (Details 4) (Employee Stock Purchase Plan, USD $)	12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Stock Purchase Plan	'	'	'
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)	0.8	0.9	0.7
Weighted-average fair value of discount on employee stock purchase plan (in dollars per share)	$14.20	$5.34	$4.20
Intrinsic value from shares settled	11,400,000	4,600,000	3,100,000
Cash received from shares issued	20,400,000	17,800,000	18,700,000
Tax benefits realized from the settlement of share-based payment arrangements	$1,100,000	$500,000	$700,000
Shares available to be issued under employee stock purchase plan (in shares)	5.2	'	'

Earnings_Per_Common_Share_Deta

Earnings Per Common Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Common Share	'	'	'	'	'	'	'	'	'	'	'
Net income (loss)	$250.40	$259.10	$236.60	$190	$226.70	$198.80	$178.60	$221.30	$936.10	$825.40	$674.50
Subtract:	'	'	'	'	'	'	'	'	'	'	'
Net income (loss) attributable to noncontrolling interest	'	'	'	'	3.5	3.4	2.7	9.2	23.4	18.8	36.2
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	33	33	33
Net income (loss) available to common stockholders	$233.40	$245.70	$222.30	$178.30	$214.90	$187.20	$167.60	$203.90	$879.70	$773.60	$605.30
Weighted-average shares outstanding	'	'	'	'	'	'	'	'	'	'	'
Basic	'	'	'	'	'	'	'	'	294.6	297.5	314.5
Dilutive effects:	'	'	'	'	'	'	'	'	'	'	'
Stock options	'	'	'	'	'	'	'	'	1.6	1	1.2
Restricted stock units	'	'	'	'	'	'	'	'	1.7	1.5	1.5
Performance share awards	'	'	'	'	'	'	'	'	0.3	0.4	0.4
Diluted	'	'	'	'	'	'	'	'	298.2	300.4	317.6
Net income (loss) per common share:	'	'	'	'	'	'	'	'	'	'	'
Basic	$0.79	$0.83	$0.76	$0.61	$0.72	$0.64	$0.56	$0.68	$2.99	$2.60	$1.92
Diluted	$0.78	$0.82	$0.75	$0.61	$0.72	$0.63	$0.56	$0.68	$2.95	$2.58	$1.91

Quarterly_Results_of_Operation2

Quarterly Results of Operations (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Results of Operations (Unaudited)	'	'	'	'	'	'	'	'	'	'	'
Total revenues	$2,672.60	$2,239.60	$2,210.60	$2,166.70	$2,295.90	$2,704.70	$2,118.60	$2,095.90	$9,289.50	$9,215.10	$8,670.70
Total expenses	2,362.70	1,919.30	1,945	1,938.50	2,035	2,513.10	1,889.10	1,817.90	8,165.50	8,255.10	7,797.90
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Net income (loss) available to common stockholders	$233.40	$245.70	$222.30	$178.30	$214.90	$187.20	$167.60	$203.90	$879.70	$773.60	$605.30
Basic earnings per common share (in dollars per share)	$0.79	$0.83	$0.76	$0.61	$0.72	$0.64	$0.56	$0.68	$2.99	$2.60	$1.92
Diluted earnings per common share (in dollars per share)	$0.78	$0.82	$0.75	$0.61	$0.72	$0.63	$0.56	$0.68	$2.95	$2.58	$1.91

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Assets	'	'	'	'
Fixed maturities, available-for-sale	$48,757.10	$50,939.30	'	'
Fixed maturities, trading	563.1	626.7	'	'
Equity securities, available-for-sale	110.5	136.5	'	'
Equity securities, trading	716.9	252.8	'	'
Mortgage loans	11,533.60	11,519.70	'	'
Real estate	1,271.60	1,180.30	'	'
Policy loans	859.7	864.9	'	'
Investment in unconsolidated entities	880	869	'	'
Other investments	2,064.40	2,422.10	'	'
Cash and cash equivalents	2,371.80	4,177.20	2,833.90	1,877.40
Accrued investment income	532.1	584.4	'	'
Premiums due and other receivables	1,241	1,084.40	'	'
Deferred acquisition costs	3,077	2,590	2,358.10	2,442.20
Property and equipment	500.7	464.2	'	'
Goodwill	1,100.30	543.4	482.3	'
Other intangibles	1,459	914.7	'	'
Separate account assets	130,018.40	81,653.80	'	'
Other assets	1,134.20	1,006.80	'	'
Total assets	208,191.40	161,830.20	'	'
Liabilities	'	'	'	'
Contractholder funds	35,958.30	37,786.50	'	'
Future policy benefits and claims	22,626.20	22,436.20	'	'
Other policyholder funds	758.9	716.4	'	'
Short-term debt	150.6	40.8	'	'
Long-term debt	2,601.40	2,671.30	'	'
Income taxes currently payable	5.2	15.3	'	'
Deferred income taxes	824	600	'	'
Separate account liabilities	130,018.40	81,653.80	'	'
Other liabilities	5,224.20	6,146.10	'	'
Total liabilities	198,167.20	152,066.40	'	'
Redeemable noncontrolling interest	247.2	60.4	22.2	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Noncontrolling interest	92.8	20	'	'
Total stockholders' equity	9,777	9,703.40	9,306.20	9,246.80
Total liabilities and stockholders' equity	208,191.40	161,830.20	'	'
Principal Financial Group, Inc. Parent Only	'	'	'	'
Assets	'	'	'	'
Fixed maturities, trading	'	10.5	'	'
Investment in unconsolidated entities	11,956.20	11,853.30	'	'
Other investments	9.3	11.1	'	'
Cash and cash equivalents	131.5	207.1	226.7	370.9
Premiums due and other receivables	'	0.1	'	'
Other assets	59.2	78	'	'
Total assets	12,156.20	12,160.10	'	'
Liabilities	'	'	'	'
Long-term debt	2,448.80	2,448.60	'	'
Other liabilities	23.2	28.1	'	'
Total liabilities	2,472	2,476.70	'	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Total stockholders' equity	9,684.20	9,683.40	'	'
Total liabilities and stockholders' equity	12,156.20	12,160.10	'	'
Principal Life Insurance Company Only	'	'	'	'
Assets	'	'	'	'
Fixed maturities, available-for-sale	42,794.70	44,614.60	'	'
Fixed maturities, trading	245.5	284.4	'	'
Equity securities, available-for-sale	102.6	131.3	'	'
Equity securities, trading	0.3	0.3	'	'
Mortgage loans	10,501.50	10,054.20	'	'
Real estate	7.9	8.4	'	'
Policy loans	830.1	834	'	'
Investment in unconsolidated entities	3,396.80	3,309.20	'	'
Other investments	1,892.40	2,834	'	'
Cash and cash equivalents	1,332.20	1,698.40	1,344.50	699.8
Accrued investment income	474.5	521.6	'	'
Premiums due and other receivables	1,029	916.7	'	'
Deferred acquisition costs	2,848.80	2,394.80	'	'
Property and equipment	422.1	402.2	'	'
Goodwill	54.3	54.3	'	'
Other intangibles	26.9	27.9	'	'
Separate account assets	83,790.20	69,217.80	'	'
Other assets	976.9	947.8	'	'
Total assets	150,726.70	138,251.90	'	'
Liabilities	'	'	'	'
Contractholder funds	34,918	37,053.30	'	'
Future policy benefits and claims	18,292.90	17,944.90	'	'
Other policyholder funds	705.1	676.5	'	'
Long-term debt	99.4	99.4	'	'
Deferred income taxes	-25	324.5	'	'
Separate account liabilities	83,790.20	69,217.80	'	'
Other liabilities	5,204.80	5,375.10	'	'
Total liabilities	142,985.40	130,691.50	'	'
Stockholders' equity	'	'	'	'
Common stock	2.5	2.5	'	'
Additional paid-in capital	5,505	5,747.60	'	'
Retained earnings (accumulated deficit)	1,738.10	1,167.70	'	'
Accumulated other comprehensive income	495.7	642.6	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	7,741.30	7,560.40	'	'
Total stockholders' equity	7,741.30	7,560.40	'	'
Total liabilities and stockholders' equity	150,726.70	138,251.90	'	'
Principal Financial Services, Inc. and Other Subsidiaries Combined	'	'	'	'
Assets	'	'	'	'
Fixed maturities, available-for-sale	6,357.50	6,681.70	'	'
Fixed maturities, trading	317.6	331.8	'	'
Equity securities, available-for-sale	7.9	5.2	'	'
Equity securities, trading	716.6	252.5	'	'
Mortgage loans	1,345.90	1,775.50	'	'
Real estate	1,263.70	1,171.90	'	'
Policy loans	29.6	30.9	'	'
Investment in unconsolidated entities	4,891.60	4,808.30	'	'
Other investments	1,238.80	1,208.40	'	'
Cash and cash equivalents	894.5	2,286.90	1,277.60	719.9
Accrued investment income	59	64.5	'	'
Premiums due and other receivables	1,814.50	1,327.10	'	'
Deferred acquisition costs	228.2	195.2	'	'
Property and equipment	78.6	62	'	'
Goodwill	1,046	489.1	'	'
Other intangibles	1,432.10	886.8	'	'
Separate account assets	46,228.20	12,436	'	'
Other assets	2,115.30	1,567.70	'	'
Total assets	70,065.60	35,581.50	'	'
Liabilities	'	'	'	'
Contractholder funds	1,330.70	1,011.90	'	'
Future policy benefits and claims	4,625	4,679.60	'	'
Other policyholder funds	54.2	40.3	'	'
Short-term debt	150.6	40.8	'	'
Long-term debt	367	433.3	'	'
Income taxes currently payable	67.4	84.7	'	'
Deferred income taxes	1,030.10	378.4	'	'
Separate account liabilities	46,228.20	12,436	'	'
Other liabilities	3,911.80	4,538.40	'	'
Total liabilities	57,765	23,643.40	'	'
Redeemable noncontrolling interest	247.2	60.4	'	'
Stockholders' equity	'	'	'	'
Additional paid-in capital	9,163.70	9,393.80	'	'
Retained earnings (accumulated deficit)	2,578.20	1,783.40	'	'
Accumulated other comprehensive income	214.3	676.1	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	11,956.20	11,853.30	'	'
Noncontrolling interest	97.2	24.4	'	'
Total stockholders' equity	12,053.40	11,877.70	'	'
Total liabilities and stockholders' equity	70,065.60	35,581.50	'	'
Eliminations, Notes Guarantor	'	'	'	'
Assets	'	'	'	'
Fixed maturities, available-for-sale	-395.1	-357	'	'
Mortgage loans	-313.8	-310	'	'
Investment in unconsolidated entities	-19,364.60	-19,101.80	'	'
Other investments	-1,076.10	-1,631.40	'	'
Cash and cash equivalents	13.6	-15.2	-14.9	86.8
Accrued investment income	-1.4	-1.7	'	'
Premiums due and other receivables	-1,602.50	-1,159.50	'	'
Other assets	-2,017.20	-1,586.70	'	'
Total assets	-24,757.10	-24,163.30	'	'
Liabilities	'	'	'	'
Contractholder funds	-290.4	-278.7	'	'
Future policy benefits and claims	-291.7	-188.3	'	'
Other policyholder funds	-0.4	-0.4	'	'
Long-term debt	-313.8	-310	'	'
Income taxes currently payable	-62.2	-69.4	'	'
Deferred income taxes	-181.1	-102.9	'	'
Other liabilities	-3,915.60	-3,795.50	'	'
Total liabilities	-5,055.20	-4,745.20	'	'
Stockholders' equity	'	'	'	'
Common stock	-2.5	-2.5	'	'
Additional paid-in capital	-14,668.70	-15,141.40	'	'
Retained earnings (accumulated deficit)	-4,316.30	-2,951.10	'	'
Accumulated other comprehensive income	-710	-1,318.70	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	-19,697.50	-19,413.70	'	'
Noncontrolling interest	-4.4	-4.4	'	'
Total stockholders' equity	-19,701.90	-19,418.10	'	'
Total liabilities and stockholders' equity	-24,757.10	-24,163.30	'	'
Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
Total stockholders' equity	0	0	0	0
Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	0.1	0.1	0.1	'
Total stockholders' equity	0.1	0.1	0.1	0.1
Series B | Principal Financial Group, Inc. Parent Only	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	$0.10	$0.10	'	'

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	$700.10	$1,158.20	$681.30	$679.80	$3,154.10	$3,219.40	$2,891
Fees and other revenues	'	'	'	'	717.6	675	636.1	598	3,222.20	2,626.70	2,526.70
Net investment income (loss)	'	'	'	'	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	56.3	122.1	32.2	22.1	-109.2	232.7	75
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	-9.5	-43.6	-49.1	-33.7	-91.5	-135.9	-147.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	-13.9	9.2	17.1	4.9	-24.5	17.3	-49.7
Net impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-116	-118.6	-197.3
Net realized capital gains (losses)	'	'	'	'	32.9	87.7	0.2	-6.7	-225.2	114.1	-122.3
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	1,154.40	1,647	1,110	1,212.50	4,683.60	5,123.90	4,616.60
Dividends to policyholders	'	'	'	'	48.2	49.7	49.5	50.3	189	197.7	210.2
Operating expenses	'	'	'	'	832.4	816.4	729.6	555.1	3,292.90	2,933.50	2,971.10
Total expenses	2,362.70	1,919.30	1,945	1,938.50	2,035	2,513.10	1,889.10	1,817.90	8,165.50	8,255.10	7,797.90
Income (loss) before income taxes	'	'	'	'	260.9	191.6	229.5	278	1,124	960	872.8
Income taxes (benefits)	'	'	'	'	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Net income (loss) attributable to noncontrolling interest	'	'	'	'	3.5	3.4	2.7	9.2	23.4	18.8	36.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	223.2	195.4	175.9	212.1	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	33	33	33
Net income (loss) available to common stockholders	233.4	245.7	222.3	178.3	214.9	187.2	167.6	203.9	879.7	773.6	605.3
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-471.9	370.1	-40.6
Comprehensive income (loss)	'	'	'	'	'	'	'	'	464.2	1,195.50	633.9
Principal Financial Group, Inc. Parent Only	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	'	'	'	'	'	0.5	0.2
Net investment income (loss)	'	'	'	'	'	'	'	'	0.4	3	-12
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	6.3	0.3	'
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	6.3	0.3	'
Total revenues	'	'	'	'	'	'	'	'	6.7	3.8	-11.8
Expenses	'	'	'	'	'	'	'	'	'	'	'
Operating expenses	'	'	'	'	'	'	'	'	140.5	170.2	116
Total expenses	'	'	'	'	'	'	'	'	140.5	170.2	116
Income (loss) before income taxes	'	'	'	'	'	'	'	'	-133.8	-166.4	-127.8
Income taxes (benefits)	'	'	'	'	'	'	'	'	-54	-67.6	-50.4
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss)	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	'	'	'	'	33	33	33
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	879.7	773.6	605.3
Net income (loss)	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-450.1	321.2	-34.5
Comprehensive income (loss)	'	'	'	'	'	'	'	'	462.6	1,127.80	603.8
Principal Life Insurance Company Only	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	'	'	'	'	2,788.10	2,878.90	2,579.60
Fees and other revenues	'	'	'	'	'	'	'	'	1,723.80	1,529.70	1,566.70
Net investment income (loss)	'	'	'	'	'	'	'	'	2,354.50	2,484.50	2,578.90
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-779.5	-194.8	442.8
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-85.6	-121.1	-130.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	'	'	'	'	-17	13.8	-51.5
Net impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-102.6	-107.3	-182.1
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	-882.1	-302.1	260.7
Total revenues	'	'	'	'	'	'	'	'	5,984.30	6,591	6,985.90
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	'	'	'	'	4,056.60	4,517.80	4,013
Dividends to policyholders	'	'	'	'	'	'	'	'	189	197.7	210.2
Operating expenses	'	'	'	'	'	'	'	'	1,887.70	1,764.20	1,965
Total expenses	'	'	'	'	'	'	'	'	6,133.30	6,479.70	6,188.20
Income (loss) before income taxes	'	'	'	'	'	'	'	'	-149	111.3	797.7
Income taxes (benefits)	'	'	'	'	'	'	'	'	-167.5	-83.2	267
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	678.1	480.4	7.2
Net income (loss)	'	'	'	'	'	'	'	'	696.6	674.9	537.9
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	696.6	674.9	537.9
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	696.6	674.9	537.9
Net income (loss)	'	'	'	'	'	'	'	'	696.6	674.9	537.9
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-146.6	315.2	100.1
Comprehensive income (loss)	'	'	'	'	'	'	'	'	550	990.1	638
Principal Financial Services, Inc. and Other Subsidiaries Combined	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	'	'	'	'	366	340.5	311.4
Fees and other revenues	'	'	'	'	'	'	'	'	1,855	1,404.10	1,257.60
Net investment income (loss)	'	'	'	'	'	'	'	'	753.8	743.1	763.2
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	663.9	454.8	-388.7
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-5.9	-14.8	-17
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	'	'	'	'	-7.5	3.5	1.8
Net impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-13.4	-11.3	-15.2
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	650.5	443.5	-403.9
Total revenues	'	'	'	'	'	'	'	'	3,625.30	2,931.20	1,928.30
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	'	'	'	'	639.2	618.5	616.9
Operating expenses	'	'	'	'	'	'	'	'	1,567.50	1,265	1,142.90
Total expenses	'	'	'	'	'	'	'	'	2,206.70	1,883.50	1,759.80
Income (loss) before income taxes	'	'	'	'	'	'	'	'	1,418.60	1,047.70	168.5
Income taxes (benefits)	'	'	'	'	'	'	'	'	412.6	287.1	-18.5
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	10.1	163.9	565.1
Net income (loss)	'	'	'	'	'	'	'	'	1,016.10	924.5	752.1
Net income (loss) attributable to noncontrolling interest	'	'	'	'	'	'	'	'	23.6	19.1	36.4
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss)	'	'	'	'	'	'	'	'	1,016.10	924.5	752.1
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-300.1	95.1	-166.6
Comprehensive income (loss)	'	'	'	'	'	'	'	'	716	1,019.60	585.5
Eliminations, Notes Guarantor	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	'	'	'	'	-356.6	-307.6	-297.8
Net investment income (loss)	'	'	'	'	'	'	'	'	29.7	24.3	45.2
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	0.1	-27.6	20.9
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	0.1	-27.6	20.9
Total revenues	'	'	'	'	'	'	'	'	-326.8	-310.9	-231.7
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	'	'	'	'	-12.2	-12.4	-13.3
Operating expenses	'	'	'	'	'	'	'	'	-302.8	-265.9	-252.8
Total expenses	'	'	'	'	'	'	'	'	-315	-278.3	-266.1
Income (loss) before income taxes	'	'	'	'	'	'	'	'	-11.8	-32.6	34.4
Income taxes (benefits)	'	'	'	'	'	'	'	'	-3.2	-1.7	0.2
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	-1,680.70	-1,549.70	-1,288
Net income (loss)	'	'	'	'	'	'	'	'	-1,689.30	-1,580.60	-1,253.80
Net income (loss) attributable to noncontrolling interest	'	'	'	'	'	'	'	'	-0.2	-0.3	-0.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	-1,689.10	-1,580.30	-1,253.60
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	-1,689.10	-1,580.30	-1,253.60
Net income (loss)	'	'	'	'	'	'	'	'	-1,689.30	-1,580.60	-1,253.80
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	424.9	-361.4	60.4
Comprehensive income (loss)	'	'	'	'	'	'	'	'	($1,264.40)	($1,942)	($1,193.40)

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities	'	'	'
Net cash provided by (used in) operating activities	$2,221.20	$3,080.80	$2,713.30
Investing activities	'	'	'
Available-for-sale securities: Purchases	-9,025.20	-8,263.90	-6,742.40
Available-for-sale securities: Sales	1,919.10	1,303.70	980.7
Available-for-sale securities: Maturities	7,359.20	6,647.50	5,760.80
Mortgage loans acquired or originated	-2,192.90	-2,538.40	-1,484.90
Mortgage loans sold or repaid	2,095.10	1,668	1,793.10
Real estate acquired	-85.6	-151.8	-129.9
Net (purchases) sales of property and equipment	-59.4	-38.9	-56.9
Purchases of interest in subsidiaries, net of cash acquired	-1,268.30	-80.4	-270.5
Net change in other investments	31.7	-157.1	-52.1
Net cash provided by (used in) investing activities	-1,226.30	-1,611.30	-202.1
Financing activities	'	'	'
Issuance of common stock	125.8	28.9	25.9
Acquisition of treasury stock	-153.6	-272.7	-556.4
Proceeds from financing element derivatives	47	51.8	75.9
Payments for financing element derivatives	-48	-49.9	-46.5
Excess tax benefits from share-based payment arrangements	10.1	10.8	2
Purchase of subsidiary shares from noncontrolling interest	-52.9	'	'
Sale of subsidiary shares to noncontrolling interest	31.8	'	'
Dividends to common stockholders	-288.4	-231.3	-213.7
Dividends to preferred stockholders	-33	-33	-33
Issuance of long-term debt	38.2	1,493.40	'
Principal repayments of long-term debt	-218.2	-450.6	-12.2
Net proceeds from (repayments of) short-term borrowings	108	-68.8	3.2
Investment contract deposits	6,716.30	6,900.40	6,302.10
Investment contract withdrawals	-8,852.70	-7,522.60	-7,079
Net increase (decrease) in banking operation deposits	-225.7	32	-18.5
Other	-5	-14.6	-4.5
Net cash provided by (used in) financing activities	-2,800.30	-126.2	-1,554.70
Net increase (decrease) in cash and cash equivalents	-1,805.40	1,343.30	956.5
Cash and cash equivalents at beginning of period	4,177.20	2,833.90	1,877.40
Cash and cash equivalents at end of period	2,371.80	4,177.20	2,833.90
Principal Financial Group, Inc. Parent Only	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	-42.8	204.8	-73.3
Investing activities	'	'	'
Available-for-sale securities: Purchases	'	'	-4.4
Available-for-sale securities: Sales	'	'	200
Available-for-sale securities: Maturities	'	'	4.4
Dividends and returns of capital received from (contributions to) unconsolidated entities	319.5	-759.2	506.5
Net change in other investments	-3.1	-0.2	-0.2
Net cash provided by (used in) investing activities	316.4	-759.4	706.3
Financing activities	'	'	'
Issuance of common stock	125.8	28.9	25.9
Acquisition of treasury stock	-153.6	-272.7	-556.4
Dividends to common stockholders	-288.4	-231.3	-213.7
Dividends to preferred stockholders	-33	-33	-33
Issuance of long-term debt	'	1,483.90	'
Principal repayments of long-term debt	'	-440.8	'
Net cash provided by (used in) financing activities	-349.2	535	-777.2
Net increase (decrease) in cash and cash equivalents	-75.6	-19.6	-144.2
Cash and cash equivalents at beginning of period	207.1	226.7	370.9
Cash and cash equivalents at end of period	131.5	207.1	226.7
Principal Life Insurance Company Only	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	2,271.70	3,133.80	2,495.50
Investing activities	'	'	'
Available-for-sale securities: Purchases	-7,850.80	-7,254.50	-6,047.20
Available-for-sale securities: Sales	1,536	1,183.90	689.5
Available-for-sale securities: Maturities	6,433.30	5,805.70	5,037
Mortgage loans acquired or originated	-2,378.40	-2,224.80	-1,372.70
Mortgage loans sold or repaid	1,918	1,422.20	1,548.60
Real estate acquired	'	'	-0.3
Net (purchases) sales of property and equipment	-52.4	-22.2	-46.7
Dividends and returns of capital received from (contributions to) unconsolidated entities	444.2	299.2	327.9
Net change in other investments	56.1	-148.4	-48.1
Net cash provided by (used in) investing activities	106	-938.9	88
Financing activities	'	'	'
Proceeds from financing element derivatives	47	51.8	75.9
Payments for financing element derivatives	-48	-49.9	-46.5
Excess tax benefits from share-based payment arrangements	3.1	5.1	0.8
Capital received from (dividends and capital paid to) parent	-249.5	-714.8	-756.5
Investment contract deposits	6,355.10	6,401.20	5,868.70
Investment contract withdrawals	-8,846.60	-7,519.80	-7,076.70
Other	-5	-14.6	-4.5
Net cash provided by (used in) financing activities	-2,743.90	-1,841	-1,938.80
Net increase (decrease) in cash and cash equivalents	-366.2	353.9	644.7
Cash and cash equivalents at beginning of period	1,698.40	1,344.50	699.8
Cash and cash equivalents at end of period	1,332.20	1,698.40	1,344.50
Principal Financial Services, Inc. and Other Subsidiaries Combined	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	-170.1	-382.5	304.7
Investing activities	'	'	'
Available-for-sale securities: Purchases	-1,186.10	-1,024.90	-696.8
Available-for-sale securities: Sales	434	134.8	116.2
Available-for-sale securities: Maturities	925.9	841.8	719.4
Mortgage loans acquired or originated	-202.2	-250.4	-169
Mortgage loans sold or repaid	634.3	382.3	339.3
Real estate acquired	-85.6	-151.8	-129.6
Net (purchases) sales of property and equipment	-7	-16.7	-10.2
Purchases of interest in subsidiaries, net of cash acquired	-1,268.30	-80.4	-270.5
Dividends and returns of capital received from (contributions to) unconsolidated entities	319.5	714.8	756.5
Net change in other investments	-70.2	-1.6	84.5
Net cash provided by (used in) investing activities	-505.7	547.9	739.8
Financing activities	'	'	'
Excess tax benefits from share-based payment arrangements	7	5.7	1.2
Purchase of subsidiary shares from noncontrolling interest	-52.9	'	'
Sale of subsidiary shares to noncontrolling interest	31.8	'	'
Issuance of long-term debt	38.2	9.5	'
Principal repayments of long-term debt	-214.4	-90.9	-69.4
Net proceeds from (repayments of) short-term borrowings	108	-68.8	3.2
Capital received from (dividends and capital paid to) parent	-763.7	460	-834.4
Investment contract deposits	361.2	499.2	433.4
Investment contract withdrawals	-6.1	-2.8	-2.3
Net increase (decrease) in banking operation deposits	-225.7	32	-18.5
Net cash provided by (used in) financing activities	-716.6	843.9	-486.8
Net increase (decrease) in cash and cash equivalents	-1,392.40	1,009.30	557.7
Cash and cash equivalents at beginning of period	2,286.90	1,277.60	719.9
Cash and cash equivalents at end of period	894.5	2,286.90	1,277.60
Eliminations, Notes Guarantor	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	162.4	124.7	-13.6
Investing activities	'	'	'
Available-for-sale securities: Purchases	11.7	15.5	6
Available-for-sale securities: Sales	-50.9	-15	-25
Mortgage loans acquired or originated	387.7	-63.2	56.8
Mortgage loans sold or repaid	-457.2	-136.5	-94.8
Dividends and returns of capital received from (contributions to) unconsolidated entities	-1,083.20	-254.8	-1,590.90
Net change in other investments	48.9	-6.9	-88.3
Net cash provided by (used in) investing activities	-1,143	-460.9	-1,736.20
Financing activities	'	'	'
Principal repayments of long-term debt	-3.8	81.1	57.2
Capital received from (dividends and capital paid to) parent	1,013.20	254.8	1,590.90
Net cash provided by (used in) financing activities	1,009.40	335.9	1,648.10
Net increase (decrease) in cash and cash equivalents	28.8	-0.3	-101.7
Cash and cash equivalents at beginning of period	-15.2	-14.9	86.8
Cash and cash equivalents at end of period	$13.60	($15.20)	($14.90)

Condensed_Consolidating_Financ5

Condensed Consolidating Financial Information (Details 4) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Assets	'	'	'	'
Fixed maturities, available-for-sale	$48,757.10	$50,939.30	'	'
Fixed maturities, trading	563.1	626.7	'	'
Equity securities, available-for-sale	110.5	136.5	'	'
Equity securities, trading	716.9	252.8	'	'
Mortgage loans	11,533.60	11,519.70	'	'
Real estate	1,271.60	1,180.30	'	'
Policy loans	859.7	864.9	'	'
Investment in unconsolidated entities	880	869	'	'
Other investments	2,064.40	2,422.10	'	'
Cash and cash equivalents	2,371.80	4,177.20	2,833.90	1,877.40
Accrued investment income	532.1	584.4	'	'
Premiums due and other receivables	1,241	1,084.40	'	'
Deferred acquisition costs	3,077	2,590	2,358.10	2,442.20
Property and equipment	500.7	464.2	'	'
Goodwill	1,100.30	543.4	482.3	'
Other intangibles	1,459	914.7	'	'
Separate account assets	130,018.40	81,653.80	'	'
Other assets	1,134.20	1,006.80	'	'
Total assets	208,191.40	161,830.20	'	'
Liabilities	'	'	'	'
Contractholder funds	35,958.30	37,786.50	'	'
Future policy benefits and claims	22,626.20	22,436.20	'	'
Other policyholder funds	758.9	716.4	'	'
Short-term debt	150.6	40.8	'	'
Long-term debt	2,601.40	2,671.30	'	'
Income taxes currently payable	5.2	15.3	'	'
Deferred income taxes	824	600	'	'
Separate account liabilities	130,018.40	81,653.80	'	'
Other liabilities	5,224.20	6,146.10	'	'
Total liabilities	198,167.20	152,066.40	'	'
Redeemable noncontrolling interest	247.2	60.4	22.2	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Noncontrolling interest	92.8	20	'	'
Total stockholders' equity	9,777	9,703.40	9,306.20	9,246.80
Total liabilities and stockholders' equity	208,191.40	161,830.20	'	'
Principal Financial Group, Inc. Parent Only	'	'	'	'
Assets	'	'	'	'
Fixed maturities, trading	'	10.5	'	'
Investment in unconsolidated entities	11,956.20	11,853.30	'	'
Other investments	9.3	11.1	'	'
Cash and cash equivalents	131.5	207.1	226.7	370.9
Premiums due and other receivables	'	0.1	'	'
Other assets	59.2	78	'	'
Total assets	12,156.20	12,160.10	'	'
Liabilities	'	'	'	'
Long-term debt	2,448.80	2,448.60	'	'
Other liabilities	23.2	28.1	'	'
Total liabilities	2,472	2,476.70	'	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Total stockholders' equity	9,684.20	9,683.40	'	'
Total liabilities and stockholders' equity	12,156.20	12,160.10	'	'
Principal Financial Services, Inc. Only	'	'	'	'
Assets	'	'	'	'
Investment in unconsolidated entities	11,647.60	10,632.10	'	'
Other investments	72.7	39.6	'	'
Cash and cash equivalents	688.7	612.5	702.4	519.7
Premiums due and other receivables	0.1	1,122.10	'	'
Other assets	94.8	51	'	'
Total assets	12,503.90	12,457.30	'	'
Liabilities	'	'	'	'
Income taxes currently payable	2.8	0.1	'	'
Other liabilities	544.9	603.9	'	'
Total liabilities	547.7	604	'	'
Stockholders' equity	'	'	'	'
Additional paid-in capital	9,163.70	9,393.80	'	'
Retained earnings (accumulated deficit)	2,578.20	1,783.40	'	'
Accumulated other comprehensive income	214.3	676.1	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	11,956.20	11,853.30	'	'
Total stockholders' equity	11,956.20	11,853.30	'	'
Total liabilities and stockholders' equity	12,503.90	12,457.30	'	'
Principal Life Insurance Company and Other Subsidiaries Combined	'	'	'	'
Assets	'	'	'	'
Fixed maturities, available-for-sale	48,757.10	50,939.30	'	'
Fixed maturities, trading	563.1	616.2	'	'
Equity securities, available-for-sale	110.5	136.5	'	'
Equity securities, trading	716.9	252.8	'	'
Mortgage loans	11,533.60	11,519.70	'	'
Real estate	1,271.60	1,180.30	'	'
Policy loans	859.7	864.9	'	'
Investment in unconsolidated entities	879.8	860.2	'	'
Other investments	1,982.50	2,371.40	'	'
Cash and cash equivalents	2,384	4,241.30	2,787.90	1,821.70
Accrued investment income	532.1	584.4	'	'
Premiums due and other receivables	2,330.40	2,206.70	'	'
Deferred acquisition costs	3,077	2,590	'	'
Property and equipment	500.7	464.2	'	'
Goodwill	1,100.30	543.4	'	'
Other intangibles	1,459	914.7	'	'
Separate account assets	130,018.40	81,653.80	'	'
Other assets	1,181	1,003.50	'	'
Total assets	209,257.70	162,943.30	'	'
Liabilities	'	'	'	'
Contractholder funds	35,958.30	37,786.50	'	'
Future policy benefits and claims	22,626.20	22,436.20	'	'
Other policyholder funds	758.9	716.4	'	'
Short-term debt	443	2,564.10	'	'
Long-term debt	1,236.90	222.7	'	'
Income taxes currently payable	44.7	47.2	'	'
Deferred income taxes	979.6	686.1	'	'
Separate account liabilities	130,018.40	81,653.80	'	'
Other liabilities	5,204.10	6,117.80	'	'
Total liabilities	197,270.10	152,230.80	'	'
Redeemable noncontrolling interest	247.2	60.4	'	'
Stockholders' equity	'	'	'	'
Common stock	17.8	17.8	'	'
Additional paid-in capital	9,057.10	8,287.70	'	'
Retained earnings (accumulated deficit)	2,387.20	1,666.70	'	'
Accumulated other comprehensive income	187.5	661.9	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-2	-2	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	11,647.60	10,632.10	'	'
Noncontrolling interest	92.8	20	'	'
Total stockholders' equity	11,740.40	10,652.10	'	'
Total liabilities and stockholders' equity	209,257.70	162,943.30	'	'
Eliminations, Shelf Registration Debt Guarantor	'	'	'	'
Assets	'	'	'	'
Investment in unconsolidated entities	-23,603.60	-22,476.60	'	'
Other investments	-0.1	'	'	'
Cash and cash equivalents	-832.4	-883.7	-883.1	-834.9
Premiums due and other receivables	-1,089.50	-2,244.50	'	'
Other assets	-200.8	-125.7	'	'
Total assets	-25,726.40	-25,730.50	'	'
Liabilities	'	'	'	'
Short-term debt	-292.4	-2,523.30	'	'
Long-term debt	-1,084.30	'	'	'
Income taxes currently payable	-42.3	-32	'	'
Deferred income taxes	-155.6	-86.1	'	'
Other liabilities	-548	-603.7	'	'
Total liabilities	-2,122.60	-3,245.10	'	'
Stockholders' equity	'	'	'	'
Common stock	-17.8	-17.8	'	'
Additional paid-in capital	-18,220.80	-17,681.50	'	'
Retained earnings (accumulated deficit)	-4,965.40	-3,450.10	'	'
Accumulated other comprehensive income	-401.8	-1,338	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	2	2	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	-23,603.80	-22,485.40	'	'
Total stockholders' equity	-23,603.80	-22,485.40	'	'
Total liabilities and stockholders' equity	-25,726.40	-25,730.50	'	'
Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
Total stockholders' equity	0	0	0	0
Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	0.1	0.1	0.1	'
Total stockholders' equity	0.1	0.1	0.1	0.1
Series B | Principal Financial Group, Inc. Parent Only	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	$0.10	$0.10	'	'

Condensed_Consolidating_Financ6

Condensed Consolidating Financial Information (Details 5) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	$700.10	$1,158.20	$681.30	$679.80	$3,154.10	$3,219.40	$2,891
Fees and other revenues	'	'	'	'	717.6	675	636.1	598	3,222.20	2,626.70	2,526.70
Net investment income (loss)	'	'	'	'	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	56.3	122.1	32.2	22.1	-109.2	232.7	75
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	-9.5	-43.6	-49.1	-33.7	-91.5	-135.9	-147.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	-13.9	9.2	17.1	4.9	-24.5	17.3	-49.7
Net impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-116	-118.6	-197.3
Net realized capital gains (losses)	'	'	'	'	32.9	87.7	0.2	-6.7	-225.2	114.1	-122.3
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	1,154.40	1,647	1,110	1,212.50	4,683.60	5,123.90	4,616.60
Dividends to policyholders	'	'	'	'	48.2	49.7	49.5	50.3	189	197.7	210.2
Operating expenses	'	'	'	'	832.4	816.4	729.6	555.1	3,292.90	2,933.50	2,971.10
Total expenses	2,362.70	1,919.30	1,945	1,938.50	2,035	2,513.10	1,889.10	1,817.90	8,165.50	8,255.10	7,797.90
Income (loss) before income taxes	'	'	'	'	260.9	191.6	229.5	278	1,124	960	872.8
Income taxes (benefits)	'	'	'	'	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Net income (loss) attributable to noncontrolling interest	'	'	'	'	3.5	3.4	2.7	9.2	23.4	18.8	36.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	223.2	195.4	175.9	212.1	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	33	33	33
Net income (loss) available to common stockholders	233.4	245.7	222.3	178.3	214.9	187.2	167.6	203.9	879.7	773.6	605.3
Net income (loss)	250.4	259.1	236.6	190	226.7	198.8	178.6	221.3	936.1	825.4	674.5
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-471.9	370.1	-40.6
Comprehensive income (loss)	'	'	'	'	'	'	'	'	464.2	1,195.50	633.9
Principal Financial Group, Inc. Parent Only	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	'	'	'	'	'	0.5	0.2
Net investment income (loss)	'	'	'	'	'	'	'	'	0.4	3	-12
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	6.3	0.3	'
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	6.3	0.3	'
Total revenues	'	'	'	'	'	'	'	'	6.7	3.8	-11.8
Expenses	'	'	'	'	'	'	'	'	'	'	'
Operating expenses	'	'	'	'	'	'	'	'	140.5	170.2	116
Total expenses	'	'	'	'	'	'	'	'	140.5	170.2	116
Income (loss) before income taxes	'	'	'	'	'	'	'	'	-133.8	-166.4	-127.8
Income taxes (benefits)	'	'	'	'	'	'	'	'	-54	-67.6	-50.4
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss)	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	'	'	'	'	33	33	33
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	879.7	773.6	605.3
Net income (loss)	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-450.1	321.2	-34.5
Comprehensive income (loss)	'	'	'	'	'	'	'	'	462.6	1,127.80	603.8
Principal Financial Services, Inc. Only	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	'	'	'	'	1	'	'
Net investment income (loss)	'	'	'	'	'	'	'	'	1.3	0.4	-3.2
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	4.6	3	-0.1
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	4.6	3	-0.1
Total revenues	'	'	'	'	'	'	'	'	6.9	3.4	-3.3
Expenses	'	'	'	'	'	'	'	'	'	'	'
Operating expenses	'	'	'	'	'	'	'	'	9	9.3	1.7
Total expenses	'	'	'	'	'	'	'	'	9	9.3	1.7
Income (loss) before income taxes	'	'	'	'	'	'	'	'	-2.1	-5.9	-5
Income taxes (benefits)	'	'	'	'	'	'	'	'	-2.9	-6.9	-9.9
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	991.7	904.4	710.8
Net income (loss)	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss)	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-476.4	366.3	-44
Comprehensive income (loss)	'	'	'	'	'	'	'	'	516.1	1,271.70	671.7
Principal Life Insurance Company and Other Subsidiaries Combined	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Premiums and other considerations	'	'	'	'	'	'	'	'	3,154.10	3,219.40	2,891
Fees and other revenues	'	'	'	'	'	'	'	'	3,250.20	2,627.30	2,529.50
Net investment income (loss)	'	'	'	'	'	'	'	'	3,136.50	3,250.80	3,387.50
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-120.1	229.6	75.1
Total other-than-temporary impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-91.5	-135.9	-147.6
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	'	'	'	'	'	'	'	'	-24.5	17.3	-49.7
Net impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	-116	-118.6	-197.3
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	-236.1	111	-122.2
Total revenues	'	'	'	'	'	'	'	'	9,304.70	9,208.50	8,685.80
Expenses	'	'	'	'	'	'	'	'	'	'	'
Benefits, claims and settlement expenses	'	'	'	'	'	'	'	'	4,683.60	5,123.90	4,616.60
Dividends to policyholders	'	'	'	'	'	'	'	'	189	197.7	210.2
Operating expenses	'	'	'	'	'	'	'	'	3,172.20	2,754.60	2,853.40
Total expenses	'	'	'	'	'	'	'	'	8,044.80	8,076.20	7,680.20
Income (loss) before income taxes	'	'	'	'	'	'	'	'	1,259.90	1,132.30	1,005.60
Income taxes (benefits)	'	'	'	'	'	'	'	'	244.8	209.1	258.6
Net income (loss)	'	'	'	'	'	'	'	'	1,015.10	923.2	747
Net income (loss) attributable to noncontrolling interest	'	'	'	'	'	'	'	'	23.4	18.8	36.2
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	991.7	904.4	710.8
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	991.7	904.4	710.8
Net income (loss)	'	'	'	'	'	'	'	'	1,015.10	923.2	747
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	-489.3	353.7	-51.1
Comprehensive income (loss)	'	'	'	'	'	'	'	'	525.8	1,276.90	695.9
Eliminations, Shelf Registration Debt Guarantor	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	'	'	'	'	-29	-1.1	-3
Net investment income (loss)	'	'	'	'	'	'	'	'	0.2	0.7	3
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	'	'	'	'	'	'	'	'	'	-0.2	'
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	'	-0.2	'
Total revenues	'	'	'	'	'	'	'	'	-28.8	-0.6	'
Expenses	'	'	'	'	'	'	'	'	'	'	'
Operating expenses	'	'	'	'	'	'	'	'	-28.8	-0.6	'
Total expenses	'	'	'	'	'	'	'	'	-28.8	-0.6	'
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	-1,984.20	-1,809.80	-1,426.50
Net income (loss)	'	'	'	'	'	'	'	'	-1,984.20	-1,809.80	-1,426.50
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	-1,984.20	-1,809.80	-1,426.50
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	-1,984.20	-1,809.80	-1,426.50
Net income (loss)	'	'	'	'	'	'	'	'	-1,984.20	-1,809.80	-1,426.50
Other comprehensive income (loss)	'	'	'	'	'	'	'	'	943.9	-671.1	89
Comprehensive income (loss)	'	'	'	'	'	'	'	'	($1,040.30)	($2,480.90)	($1,337.50)

Condensed_Consolidating_Financ7

Condensed Consolidating Financial Information (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities	'	'	'
Net cash provided by (used in) operating activities	$2,221.20	$3,080.80	$2,713.30
Investing activities	'	'	'
Available-for-sale securities: Purchases	-9,025.20	-8,263.90	-6,742.40
Available-for-sale securities: Sales	1,919.10	1,303.70	980.7
Available-for-sale securities: Maturities	7,359.20	6,647.50	5,760.80
Mortgage loans acquired or originated	-2,192.90	-2,538.40	-1,484.90
Mortgage loans sold or repaid	2,095.10	1,668	1,793.10
Real estate acquired	-85.6	-151.8	-129.9
Net (purchases) sales of property and equipment	-59.4	-38.9	-56.9
Purchases of interest in subsidiaries, net of cash acquired	-1,268.30	-80.4	-270.5
Net change in other investments	31.7	-157.1	-52.1
Net cash provided by (used in) investing activities	-1,226.30	-1,611.30	-202.1
Financing activities	'	'	'
Issuance of common stock	125.8	28.9	25.9
Acquisition of treasury stock	-153.6	-272.7	-556.4
Proceeds from financing element derivatives	47	51.8	75.9
Payments for financing element derivatives	-48	-49.9	-46.5
Excess tax benefits from share-based payment arrangements	10.1	10.8	2
Purchase of subsidiary shares from noncontrolling interest	-52.9	'	'
Sale of subsidiary shares to noncontrolling interest	31.8	'	'
Dividends to common stockholders	-288.4	-231.3	-213.7
Dividends to preferred stockholders	-33	-33	-33
Issuance of long-term debt	38.2	1,493.40	'
Principal repayments of long-term debt	-218.2	-450.6	-12.2
Net proceeds from (repayments of) short-term borrowings	108	-68.8	3.2
Investment contract deposits	6,716.30	6,900.40	6,302.10
Investment contract withdrawals	-8,852.70	-7,522.60	-7,079
Net increase (decrease) in banking operation deposits	-225.7	32	-18.5
Other	-5	-14.6	-4.5
Net cash provided by (used in) financing activities	-2,800.30	-126.2	-1,554.70
Net increase (decrease) in cash and cash equivalents	-1,805.40	1,343.30	956.5
Cash and cash equivalents at beginning of period	4,177.20	2,833.90	1,877.40
Cash and cash equivalents at end of period	2,371.80	4,177.20	2,833.90
Principal Financial Group, Inc. Parent Only	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	-42.8	204.8	-73.3
Investing activities	'	'	'
Available-for-sale securities: Purchases	'	'	-4.4
Available-for-sale securities: Sales	'	'	200
Available-for-sale securities: Maturities	'	'	4.4
Dividends and returns of capital received from (contributions to) unconsolidated entities	319.5	-759.2	506.5
Net change in other investments	-3.1	-0.2	-0.2
Net cash provided by (used in) investing activities	316.4	-759.4	706.3
Financing activities	'	'	'
Issuance of common stock	125.8	28.9	25.9
Acquisition of treasury stock	-153.6	-272.7	-556.4
Dividends to common stockholders	-288.4	-231.3	-213.7
Dividends to preferred stockholders	-33	-33	-33
Issuance of long-term debt	'	1,483.90	'
Principal repayments of long-term debt	'	-440.8	'
Net cash provided by (used in) financing activities	-349.2	535	-777.2
Net increase (decrease) in cash and cash equivalents	-75.6	-19.6	-144.2
Cash and cash equivalents at beginning of period	207.1	226.7	370.9
Cash and cash equivalents at end of period	131.5	207.1	226.7
Principal Financial Services, Inc. Only	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	1,019	-1,145	70.5
Investing activities	'	'	'
Dividends and returns of capital received from (contributions to) unconsolidated entities	-594.6	381	624.1
Net change in other investments	-28.7	-35.1	-5.4
Net cash provided by (used in) investing activities	-623.3	345.9	618.7
Financing activities	'	'	'
Net proceeds from (repayments of) short-term borrowings	'	-50	'
Capital received from (dividends and capital paid to) parent	-319.5	759.2	-506.5
Net cash provided by (used in) financing activities	-319.5	709.2	-506.5
Net increase (decrease) in cash and cash equivalents	76.2	-89.9	182.7
Cash and cash equivalents at beginning of period	612.5	702.4	519.7
Cash and cash equivalents at end of period	688.7	612.5	702.4
Principal Life Insurance Company and Other Subsidiaries Combined	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	2,340.20	1,762	2,795
Investing activities	'	'	'
Available-for-sale securities: Purchases	-9,025.20	-8,263.90	-6,738
Available-for-sale securities: Sales	1,919.10	1,303.70	780.7
Available-for-sale securities: Maturities	7,359.20	6,647.50	5,756.40
Mortgage loans acquired or originated	-2,192.90	-2,538.40	-1,484.90
Mortgage loans sold or repaid	2,095.10	1,668	1,793.10
Real estate acquired	-85.6	-151.8	-129.9
Net (purchases) sales of property and equipment	-59.4	-38.9	-56.9
Purchases of interest in subsidiaries, net of cash acquired	-1,268.30	-80.4	-270.5
Net change in other investments	63.5	-121.8	-46.5
Net cash provided by (used in) investing activities	-1,194.50	-1,576	-396.5
Financing activities	'	'	'
Proceeds from financing element derivatives	47	51.8	75.9
Payments for financing element derivatives	-48	-49.9	-46.5
Excess tax benefits from share-based payment arrangements	10.1	10.8	2
Purchase of subsidiary shares from noncontrolling interest	-52.9	'	'
Sale of subsidiary shares to noncontrolling interest	31.8	'	'
Issuance of long-term debt	1,122.50	9.5	'
Principal repayments of long-term debt	-218.2	-9.8	-12.2
Net proceeds from (repayments of) short-term borrowings	-2,122.80	2,240.80	-27.5
Capital received from (dividends and capital paid to) parent	594.6	-381	-624.1
Investment contract deposits	6,716.30	6,900.40	6,302.10
Investment contract withdrawals	-8,852.70	-7,522.60	-7,079
Net increase (decrease) in banking operation deposits	-225.7	32	-18.5
Other	-5	-14.6	-4.5
Net cash provided by (used in) financing activities	-3,003	1,267.40	-1,432.30
Net increase (decrease) in cash and cash equivalents	-1,857.30	1,453.40	966.2
Cash and cash equivalents at beginning of period	4,241.30	2,787.90	1,821.70
Cash and cash equivalents at end of period	2,384	4,241.30	2,787.90
Eliminations, Shelf Registration Debt Guarantor	'	'	'
Operating activities	'	'	'
Net cash provided by (used in) operating activities	-1,095.20	2,259	-78.9
Investing activities	'	'	'
Dividends and returns of capital received from (contributions to) unconsolidated entities	275.1	378.2	-1,130.60
Net cash provided by (used in) investing activities	275.1	378.2	-1,130.60
Financing activities	'	'	'
Issuance of long-term debt	-1,084.30	'	'
Net proceeds from (repayments of) short-term borrowings	2,230.80	-2,259.60	30.7
Capital received from (dividends and capital paid to) parent	-275.1	-378.2	1,130.60
Net cash provided by (used in) financing activities	871.4	-2,637.80	1,161.30
Net increase (decrease) in cash and cash equivalents	51.3	-0.6	-48.2
Cash and cash equivalents at beginning of period	-883.7	-883.1	-834.9
Cash and cash equivalents at end of period	($832.40)	($883.70)	($883.10)

Schedule_I_Summary_of_Investme1

Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Summary of Investments - Other Than Investments in Related Parties	'
Cost	$63,671.70
Amount as shown in the Consolidated Statement of Financial Position	66,756.90
U.S. government and agencies | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	818.2
Value	780.5
Amount as shown in the Consolidated Statement of Financial Position	780.5
States and political subdivisions | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	3,622.80
Value	3,658
Amount as shown in the Consolidated Statement of Financial Position	3,658
Non-U.S. governments | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	853.2
Value	996.8
Amount as shown in the Consolidated Statement of Financial Position	996.8
Public utilities | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	4,846.60
Value	4,424
Amount as shown in the Consolidated Statement of Financial Position	4,424
Redeemable preferred stock | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	37.8
Value	41.2
Amount as shown in the Consolidated Statement of Financial Position	41.2
All other corporate bonds | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	25,396.20
Value	27,453.80
Amount as shown in the Consolidated Statement of Financial Position	27,453.80
Residential mortgage-backed pass-through securities | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	2,799.10
Value	2,845.20
Amount as shown in the Consolidated Statement of Financial Position	2,845.20
Commercial mortgage-backed securities | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	4,078
Value	4,026.40
Amount as shown in the Consolidated Statement of Financial Position	4,026.40
Collateralized debt obligations | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	391.9
Value	363.4
Amount as shown in the Consolidated Statement of Financial Position	363.4
Other debt obligations | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	4,157.50
Value	4,167.80
Amount as shown in the Consolidated Statement of Financial Position	4,167.80
Fixed maturities | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	47,001.30
Value	48,757.10
Amount as shown in the Consolidated Statement of Financial Position	48,757.10
Fixed maturities | Trading	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	563.1
Value	563.1
Amount as shown in the Consolidated Statement of Financial Position	563.1
Common stocks: Banks, trust and insurance companies | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	60.8
Value	51.1
Amount as shown in the Consolidated Statement of Financial Position	51.1
Common stocks: Industrial, miscellaneous and all other | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	7.7
Value	10.2
Amount as shown in the Consolidated Statement of Financial Position	10.2
Non-redeemable preferred stock | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	45.3
Value	49.2
Amount as shown in the Consolidated Statement of Financial Position	49.2
Equity securities | Available-for-sale	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	113.8
Value	110.5
Amount as shown in the Consolidated Statement of Financial Position	110.5
Equity securities | Trading	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	716.9
Value	716.9
Amount as shown in the Consolidated Statement of Financial Position	716.9
Mortgage loans	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	11,603.30
Amount as shown in the Consolidated Statement of Financial Position	11,533.60
Real estate acquired in satisfaction of debt	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	213.6
Amount as shown in the Consolidated Statement of Financial Position	213.8
Other real estate	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	1,058
Amount as shown in the Consolidated Statement of Financial Position	1,057.80
Policy loans	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	859.7
Amount as shown in the Consolidated Statement of Financial Position	859.7
Investments: Other investments	'
Summary of Investments - Other Than Investments in Related Parties	'
Cost	1,542
Amount as shown in the Consolidated Statement of Financial Position	$2,944.40

Schedule_II_Condensed_Financia1

Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Assets	'	'	'	'
Fixed maturities, trading	$563.10	$626.70	'	'
Cash and cash equivalents	2,371.80	4,177.20	2,833.90	1,877.40
Other investments	2,944.40	3,291.10	'	'
Deferred income taxes	49.6	20.8	'	'
Investment in subsidiary	880	869	'	'
Total assets	208,191.40	161,830.20	'	'
Liabilities	'	'	'	'
Long-term debt	2,601.40	2,671.30	'	'
Total liabilities	198,167.20	152,066.40	'	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income (loss)	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Total liabilities and stockholders' equity	208,191.40	161,830.20	'	'
Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	0.1	0.1	0.1	'
Principal Financial Group, Inc. Parent Only	'	'	'	'
Assets	'	'	'	'
Fixed maturities, trading	'	10.5	'	'
Cash and cash equivalents	131.5	207.1	226.7	370.9
Other investments	9.3	11.1	'	'
Income taxes receivable	22.2	35.8	'	'
Deferred income taxes	17.2	20.6	'	'
Amounts receivable from subsidiary	0.8	0.9	'	'
Other assets	19	20.8	'	'
Investment in subsidiary	11,956.20	11,853.30	'	'
Total assets	12,156.20	12,160.10	'	'
Liabilities	'	'	'	'
Amounts payable to subsidiary	1.4	2.1	'	'
Long-term debt	2,448.80	2,448.60	'	'
Accrued interest payable	21.8	22.3	'	'
Other liabilities	'	3.7	'	'
Total liabilities	2,472	2,476.70	'	'
Stockholders' equity	'	'	'	'
Common stock	4.6	4.5	'	'
Additional paid-in capital	9,798.90	9,730.90	'	'
Retained earnings (accumulated deficit)	5,405.40	4,862	'	'
Accumulated other comprehensive income (loss)	183.2	640.3	'	'
Treasury stock, at cost (164.1 million and 159.7 million shares in 2013 and 2012)	-5,708	-5,554.40	'	'
Total stockholders' equity attributable to Principal Financial Group, Inc.	9,684.20	9,683.40	'	'
Total liabilities and stockholders' equity	12,156.20	12,160.10	'	'
Principal Financial Group, Inc. Parent Only | Series A	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	'	'	'	'
Principal Financial Group, Inc. Parent Only | Series B	'	'	'	'
Stockholders' equity	'	'	'	'
Preferred stock, value	$0.10	$0.10	'	'

Schedule_II_Condensed_Financia2

Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, except Per Share data, unless otherwise specified
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)	459.3	453.5
Common stock, outstanding (in shares)	295.2	293.8
Treasury stock (in shares)	164.1	159.7
Series A	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, liquidation preference (in dollars per share)	$100	$100
Preferred stock, authorized (in shares)	3	3
Preferred stock, issued (in shares)	3	3
Preferred stock, outstanding (in shares)	3	3
Series B	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, liquidation preference (in dollars per share)	$25	$25
Preferred stock, authorized (in shares)	10	10
Preferred stock, issued (in shares)	10	10
Preferred stock, outstanding (in shares)	10	10
Principal Financial Group, Inc. Parent Only	'	'
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)	459.3	453.5
Common stock, outstanding (in shares)	295.2	293.8
Treasury stock (in shares)	164.1	159.7
Principal Financial Group, Inc. Parent Only | Series A	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, liquidation preference (in dollars per share)	$100	$100
Preferred stock, authorized (in shares)	3	3
Preferred stock, issued (in shares)	3	3
Preferred stock, outstanding (in shares)	3	3
Principal Financial Group, Inc. Parent Only | Series B	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, liquidation preference (in dollars per share)	$25	$25
Preferred stock, authorized (in shares)	10	10
Preferred stock, issued (in shares)	10	10
Preferred stock, outstanding (in shares)	10	10

Schedule_II_Condensed_Financia3

Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 3) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	$717.60	$675	$636.10	$598	$3,222.20	$2,626.70	$2,526.70
Net investment income (loss)	'	'	'	'	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30
Net realized capital gains (losses)	'	'	'	'	32.9	87.7	0.2	-6.7	-225.2	114.1	-122.3
Total revenues	2,672.60	2,239.60	2,210.60	2,166.70	2,295.90	2,704.70	2,118.60	2,095.90	9,289.50	9,215.10	8,670.70
Expenses	'	'	'	'	'	'	'	'	'	'	'
Other operating costs and expenses	'	'	'	'	832.4	816.4	729.6	555.1	3,292.90	2,933.50	2,971.10
Total expenses	2,362.70	1,919.30	1,945	1,938.50	2,035	2,513.10	1,889.10	1,817.90	8,165.50	8,255.10	7,797.90
Income before income taxes	'	'	'	'	260.9	191.6	229.5	278	1,124	960	872.8
Income taxes (benefits)	'	'	'	'	34.2	-7.2	50.9	56.7	187.9	134.6	198.3
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	223.2	195.4	175.9	212.1	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	8.3	8.2	8.3	8.2	33	33	33
Net income (loss) available to common stockholders	233.4	245.7	222.3	178.3	214.9	187.2	167.6	203.9	879.7	773.6	605.3
Principal Financial Group, Inc. Parent Only	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	'	'	'
Fees and other revenues	'	'	'	'	'	'	'	'	'	0.5	0.2
Net investment income (loss)	'	'	'	'	'	'	'	'	0.4	3	-12
Net realized capital gains (losses)	'	'	'	'	'	'	'	'	6.3	0.3	'
Total revenues	'	'	'	'	'	'	'	'	6.7	3.8	-11.8
Expenses	'	'	'	'	'	'	'	'	'	'	'
Other operating costs and expenses	'	'	'	'	'	'	'	'	140.5	170.2	116
Total expenses	'	'	'	'	'	'	'	'	140.5	170.2	116
Income before income taxes	'	'	'	'	'	'	'	'	-133.8	-166.4	-127.8
Income taxes (benefits)	'	'	'	'	'	'	'	'	-54	-67.6	-50.4
Equity in the net income (loss) of subsidiaries	'	'	'	'	'	'	'	'	992.5	905.4	715.7
Net income (loss) attributable to Principal Financial Group, Inc.	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Preferred stock dividends	'	'	'	'	'	'	'	'	33	33	33
Net income (loss) available to common stockholders	'	'	'	'	'	'	'	'	$879.70	$773.60	$605.30

Schedule_II_Condensed_Financia4

Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 4) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net income (loss)	$250.40	$259.10	$236.60	$190	$226.70	$198.80	$178.60	$221.30	$936.10	$825.40	$674.50
Operating activities	'	'	'	'	'	'	'	'	'	'	'
Net realized capital (gains) losses	'	'	'	'	-32.9	-87.7	-0.2	6.7	225.2	-114.1	122.3
Net cash flows for trading securities	'	'	'	'	'	'	'	'	-76	335.8	110.8
Current and deferred income tax benefits	'	'	'	'	'	'	'	'	211.7	18.4	17.8
Stock-based compensation	'	'	'	'	'	'	'	'	68.5	63.8	43.4
Other	'	'	'	'	'	'	'	'	-490.6	-42.2	705.1
Net cash provided by (used in) operating activities	'	'	'	'	'	'	'	'	2,221.20	3,080.80	2,713.30
Investing activities	'	'	'	'	'	'	'	'	'	'	'
Available-for-sale securities: Purchases	'	'	'	'	'	'	'	'	-9,025.20	-8,263.90	-6,742.40
Available-for-sale securities: Sales	'	'	'	'	'	'	'	'	1,919.10	1,303.70	980.7
Available-for-sale securities: Maturities	'	'	'	'	'	'	'	'	7,359.20	6,647.50	5,760.80
Net change in other investments	'	'	'	'	'	'	'	'	31.7	-157.1	-52.1
Net cash provided by (used in) investing activities	'	'	'	'	'	'	'	'	-1,226.30	-1,611.30	-202.1
Financing activities	'	'	'	'	'	'	'	'	'	'	'
Issuance of common stock	'	'	'	'	'	'	'	'	125.8	28.9	25.9
Acquisition of treasury stock	'	'	'	'	'	'	'	'	-153.6	-272.7	-556.4
Dividends to common stockholders	'	'	'	'	'	'	'	'	-288.4	-231.3	-213.7
Dividends to preferred stockholders	'	'	'	'	'	'	'	'	-33	-33	-33
Principal repayments of long-term debt	'	'	'	'	'	'	'	'	-218.2	-450.6	-12.2
Issuance of long-term debt	'	'	'	'	'	'	'	'	38.2	1,493.40	'
Net cash provided by (used in) financing activities	'	'	'	'	'	'	'	'	-2,800.30	-126.2	-1,554.70
Net increase (decrease) in cash and cash equivalents	'	'	'	'	'	'	'	'	-1,805.40	1,343.30	956.5
Cash and cash equivalents at beginning of period	'	'	'	4,177.20	'	'	'	2,833.90	4,177.20	2,833.90	1,877.40
Cash and cash equivalents at end of period	2,371.80	'	'	'	4,177.20	'	'	'	2,371.80	4,177.20	2,833.90
Principal Financial Group, Inc. Parent Only	'	'	'	'	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net income (loss)	'	'	'	'	'	'	'	'	912.7	806.6	638.3
Operating activities	'	'	'	'	'	'	'	'	'	'	'
Equity in the net (income) loss of subsidiaries	'	'	'	'	'	'	'	'	-992.5	-905.4	-715.7
Net realized capital (gains) losses	'	'	'	'	'	'	'	'	-6.3	-0.3	'
Net cash flows for trading securities	'	'	'	'	'	'	'	'	10.4	258.2	21.7
Current and deferred income tax benefits	'	'	'	'	'	'	'	'	12.6	-2.3	-3.7
Stock-based compensation	'	'	'	'	'	'	'	'	2.2	2.2	1.6
Other	'	'	'	'	'	'	'	'	18.1	45.8	-15.5
Net cash provided by (used in) operating activities	'	'	'	'	'	'	'	'	-42.8	204.8	-73.3
Investing activities	'	'	'	'	'	'	'	'	'	'	'
Available-for-sale securities: Purchases	'	'	'	'	'	'	'	'	'	'	-4.4
Available-for-sale securities: Sales	'	'	'	'	'	'	'	'	'	'	200
Available-for-sale securities: Maturities	'	'	'	'	'	'	'	'	'	'	4.4
Net change in other investments	'	'	'	'	'	'	'	'	-3.1	-0.2	-0.2
Dividends and returns of capital received from (contributions to) unconsolidated entities	'	'	'	'	'	'	'	'	319.5	-759.2	506.5
Net cash provided by (used in) investing activities	'	'	'	'	'	'	'	'	316.4	-759.4	706.3
Financing activities	'	'	'	'	'	'	'	'	'	'	'
Issuance of common stock	'	'	'	'	'	'	'	'	125.8	28.9	25.9
Acquisition of treasury stock	'	'	'	'	'	'	'	'	-153.6	-272.7	-556.4
Dividends to common stockholders	'	'	'	'	'	'	'	'	-288.4	-231.3	-213.7
Dividends to preferred stockholders	'	'	'	'	'	'	'	'	-33	-33	-33
Principal repayments of long-term debt	'	'	'	'	'	'	'	'	'	-440.8	'
Issuance of long-term debt	'	'	'	'	'	'	'	'	'	1,483.90	'
Net cash provided by (used in) financing activities	'	'	'	'	'	'	'	'	-349.2	535	-777.2
Net increase (decrease) in cash and cash equivalents	'	'	'	'	'	'	'	'	-75.6	-19.6	-144.2
Cash and cash equivalents at beginning of period	'	'	'	207.1	'	'	'	226.7	207.1	226.7	370.9
Cash and cash equivalents at end of period	$131.50	'	'	'	$207.10	'	'	'	$131.50	$207.10	$226.70

Schedule_II_Condensed_Financia5

Schedule II - Condensed Financial Information of Registrant (Parent Only) (Details 5) (Principal Financial Group, Inc. Parent Only, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Principal Financial Group, Inc. Parent Only	'	'	'
Cash Dividends and Returns of Capital Received from (Capital Contributed to) Unconsolidated Entity	'	'	'
Dividends and returns of capital received from (contributions to) unconsolidated entities	$319.50	($759.20)	$506.50

Schedule_III_Supplementary_Ins1

Schedule III - Supplementary Insurance Information (Details) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplementary Insurance Information	'	'	'	'	'	'	'	'
Deferred acquisition costs	$2,590	'	'	'	$3,077	$2,590	$2,358.10	$2,442.20
Future policy benefits and claims	22,436.20	'	'	'	22,626.20	22,436.20	'	'
Contractholder and other policyholder funds	38,502.90	'	'	'	36,717.20	38,502.90	'	'
Premiums and other considerations	700.1	1,158.20	681.3	679.8	3,154.10	3,219.40	2,891	'
Net investment income (loss)	845.3	783.8	801	824.8	3,138.40	3,254.90	3,375.30	'
Benefits, claims and settlement expenses	1,154.40	1,647	1,110	1,212.50	4,683.60	5,123.90	4,616.60	'
Amortization of deferred acquisition costs	'	'	'	'	187.1	94.9	271.4	'
Other operating expenses	'	'	'	'	3,105.80	2,838.60	2,699.70	'
Retirement and Investor Services	'	'	'	'	'	'	'	'
Supplementary Insurance Information	'	'	'	'	'	'	'	'
Deferred acquisition costs	699.4	'	'	'	848.9	699.4	'	'
Future policy benefits and claims	9,702.70	'	'	'	9,975.60	9,702.70	'	'
Contractholder and other policyholder funds	32,801.40	'	'	'	30,537.50	32,801.40	'	'
Premiums and other considerations	'	'	'	'	1,045.50	1,162.60	390.4	'
Net investment income (loss)	'	'	'	'	1,933.30	2,075.40	2,182.80	'
Benefits, claims and settlement expenses	'	'	'	'	2,303.40	2,629.10	1,933.30	'
Amortization of deferred acquisition costs	'	'	'	'	75	84.8	119.4	'
Other operating expenses	'	'	'	'	1,529.90	1,362.50	1,258.50	'
Principal Global Investors	'	'	'	'	'	'	'	'
Supplementary Insurance Information	'	'	'	'	'	'	'	'
Net investment income (loss)	'	'	'	'	17	15.4	15.1	'
Other operating expenses	'	'	'	'	545.7	456.9	429.3	'
Principal International	'	'	'	'	'	'	'	'
Supplementary Insurance Information	'	'	'	'	'	'	'	'
Deferred acquisition costs	195.3	'	'	'	228.2	195.3	'	'
Future policy benefits and claims	4,435.50	'	'	'	4,220.20	4,435.50	'	'
Contractholder and other policyholder funds	108.5	'	'	'	172.2	108.5	'	'
Premiums and other considerations	'	'	'	'	291.6	284.6	264.5	'
Net investment income (loss)	'	'	'	'	447.1	435.2	469.9	'
Benefits, claims and settlement expenses	'	'	'	'	569	567.2	581.7	'
Amortization of deferred acquisition costs	'	'	'	'	16.5	12.6	8.4	'
Other operating expenses	'	'	'	'	318	208.5	184.8	'
U.S. Insurance Solutions	'	'	'	'	'	'	'	'
Supplementary Insurance Information	'	'	'	'	'	'	'	'
Deferred acquisition costs	1,695.30	'	'	'	1,999.90	1,695.30	'	'
Future policy benefits and claims	8,247.60	'	'	'	8,389	8,247.60	'	'
Contractholder and other policyholder funds	5,867.40	'	'	'	6,293.90	5,867.40	'	'
Premiums and other considerations	'	'	'	'	1,816.50	1,769.30	1,724	'
Net investment income (loss)	'	'	'	'	686.3	675.2	669.9	'
Benefits, claims and settlement expenses	'	'	'	'	1,826	1,935.50	1,725.10	'
Amortization of deferred acquisition costs	'	'	'	'	95.6	-2.5	143.6	'
Other operating expenses	'	'	'	'	689	662	630.2	'
Corporate	'	'	'	'	'	'	'	'
Supplementary Insurance Information	'	'	'	'	'	'	'	'
Future policy benefits and claims	50.4	'	'	'	41.4	50.4	'	'
Contractholder and other policyholder funds	-274.4	'	'	'	-286.4	-274.4	'	'
Premiums and other considerations	'	'	'	'	0.5	2.9	512.1	'
Net investment income (loss)	'	'	'	'	54.7	53.7	37.6	'
Benefits, claims and settlement expenses	'	'	'	'	-14.8	-7.9	376.5	'
Other operating expenses	'	'	'	'	$23.20	$148.70	$196.90	'

Schedule_IV_Reinsurance_Detail

Schedule IV - Reinsurance (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reinsurance information	'	'	'
Gross amount	$3,524.80	$3,554.10	$3,205.60
Ceded to other companies	373.2	337.3	317.6
Assumed from other companies	2.5	2.6	3
Life insurance in force	'	'	'
Reinsurance information	'	'	'
Gross amount	317,154.50	286,435.30	256,880.30
Ceded to other companies	144,024.90	115,315.70	94,839.70
Assumed from other companies	1,455.40	1,606.20	1,814.90
Net amount	174,585	172,725.80	163,855.50
Percentage of amount assumed to net (as a percent)	0.80%	0.90%	1.10%
Premiums	'	'	'
Reinsurance information	'	'	'
Gross amount	3,524.80	3,554.10	3,205.60
Ceded to other companies	373.2	337.3	317.6
Assumed from other companies	2.5	2.6	3
Net amount	3,154.10	3,219.40	2,891
Percentage of amount assumed to net (as a percent)	0.10%	0.10%	0.10%
Life insurance premiums	'	'	'
Reinsurance information	'	'	'
Gross amount	2,216.90	2,289.40	1,490.80
Ceded to other companies	205.2	174.4	158.5
Assumed from other companies	2.5	2.6	3
Net amount	2,014.20	2,117.60	1,335.30
Percentage of amount assumed to net (as a percent)	0.10%	0.10%	0.20%
Accident and health insurance premiums	'	'	'
Reinsurance information	'	'	'
Gross amount	1,307.90	1,264.70	1,714.80
Ceded to other companies	168	162.9	159.1
Net amount	$1,139.90	$1,101.80	$1,555.70