Reinsurance Group of America (RGA) 10-K 27 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Jan. 31, 2019	Jun. 30, 2018
Document And Entitiy Information [Abstract]
Document type	10-K
Document period end date	Dec. 31, 2018
Amendment flag	false
Entity registrant name	REINSURANCE GROUP OF AMERICA INC
Entity central index key	898,174
Entity current reporting status	Yes
Entity voluntary filers	No
Current fiscal year end date	--12-31
Entity filer category	Large Accelerated Filer
Entity well known seasoned issuer	Yes
Common Shares Outstanding		62,839,877
Entity public float			$ 8.5
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fixed Maturity Securities [Abstract]
Available-for-sale at fair value (amortized cost of $38,882,168 and $35,281,412)	$ 39,992,346	$ 38,150,820
Equity Securities, FV-NI	82,197	100,152
Mortgage loans on real estate (net of allowances of $11,286 and $9,384)	4,966,298	4,400,533
Policy loans	1,344,980	1,357,624
Funds withheld at interest	5,761,471	6,083,388
Short-term investments	142,598	93,304
Other invested assets	1,915,297	1,505,332
Total investments	54,205,187	51,691,153
Cash and cash equivalents	1,889,733	1,303,524
Accrued investment income	427,893	392,721
Premiums receivable and other reinsurance balances	3,017,868	2,338,481
Reinsurance ceded receivables	757,572	782,027
Deferred policy acquisition costs	3,397,770	3,239,824
Other assets	839,222	767,088
Total assets	64,535,245	60,514,818
Liabilities and Stockholders’ Equity
Future policy benefits	25,285,400	22,363,241
Interest-sensitive contract liabilities	18,004,526	16,227,642
Other policy claims and benefits	5,642,755	4,992,074
Other reinsurance balances	487,177	488,739
Deferred income taxes	1,798,800	2,198,309
Other liabilities	1,396,200	1,102,975
Long-term debt	2,787,873	2,788,365
Collateral finance and securitization notes	681,961	783,938
Total liabilities	56,084,692	50,945,283
Commitments and contingent liabilities (See Note 12)
Stockholders Equity:
Preferred stock (par value $.01 per share; 10,000,000 shares authorized; no shares issued or outstanding)	0	0
Common stock (par value $.01 per share; 140,000,000 shares authorized; shares issued: 79,137,758 at December 31, 2018 and 2017)	791	791
Additional paid-in-capital	1,898,652	1,870,906
Retained earnings	7,284,949	6,736,265
Treasury stock, at cost - 16,323,390 and 14,685,663 shares	(1,370,602)	(1,102,058)
Accumulated other comprehensive income	636,763	2,063,631
Total stockholders’ equity	8,450,553	9,569,535
Total liabilities and stockholders’ equity	$ 64,535,245	$ 60,514,818

CONSOLIDATED BALANCE SHEETS PAR

CONSOLIDATED BALANCE SHEETS PARENTHETICAL - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Available for Sale at Fair value - Amortized cost	$ 38,882,168	$ 35,281,412
Available-for-sale Equity Securities, Amortized Cost Basis	$ 107,721	$ 102,841
Preferred stock par value	$ 0.01	$ 0.01
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock par value	$ 0.01	$ 0.01
Common stock shares authorized	140,000,000	140,000,000
Common Stock, Shares, Issued	79,137,758	79,137,758
Common stock shares outstanding	62,814,368	64,452,095
Treasury Shares Held	16,323,390	14,685,663
Allowances for Loan and Lease Losses, Real Estate	$ 11,286	$ 9,384

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums	$ 10,543,776	$ 9,841,130	$ 9,248,871
Investment income, net of related expenses	2,138,525	2,154,651	1,911,886
Investment related gains (losses), net:
Other-than-temporary impairments on fixed maturity securities	(28,494)	(42,639)	(38,805)
Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income	0	0	74
Other investment related gains (losses), net	(141,594)	210,519	132,926
Total investment related gains (losses), net	(170,088)	167,880	94,195
Other revenues	363,451	352,108	266,559
Total revenues	12,875,664	12,515,769	11,521,511
Benefits and expenses
Claims and other policy benefits	9,318,929	8,518,917	7,993,375
Interest credited	425,204	502,040	364,691
Policy acquisition costs and other insurance expenses	1,322,520	1,466,646	1,310,540
Other operating expenses	786,137	710,690	645,509
Interest expense	147,355	146,025	137,623
Collateral finance and securitization expense	29,699	28,636	25,827
Total benefits and expenses	12,029,844	11,372,954	10,477,565
Income before income taxes	845,820	1,142,815	1,043,946
Provision for income taxes	129,978	(679,366)	342,503
Net income	$ 715,842	$ 1,822,181	$ 701,443
Earnings per share
Basic earnings per share (in dollars per share)	$ 11.25	$ 28.28	$ 10.91
Diluted earnings per share (in dollars per share)	$ 11	$ 27.71	$ 10.79

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Comprehensive income
Net Income (Loss) Attributable to Parent	$ 715,842	$ 1,822,181	$ 701,443
Other comprehensive income (loss), net of tax:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(79,775)	69,126	8,610
Net unrealized investment gains (losses)	(1,344,502)	698,078	419,336
Change in other-than-temporary impairment losses on fixed maturity securities		(244)	(947)
Defined benefit pension and postretirement plan adjustments	(18)	726	3,099
Total other comprehensive income (loss), net of tax	(1,424,295)	767,930	431,045
Total comprehensive income (loss)	$ (708,453)	$ 2,590,111	$ 1,132,488

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Treasury Stock Member	Accumulated Other Comprehensive Income Member
Total stockholders equity at Dec. 31, 2015	$ 6,135,381	$ 791	$ 1,816,142	$ 4,620,303	$ (1,010,139)	$ 708,284
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	701,443			701,443
Other Comprehensive Income (Loss), Net of Tax	431,045					431,045
Dividends to stockholders, $2.20 per share	(100,371)			(100,371)
Purchase of treasury stock	(122,916)				122,916
Reissuance of treasury stock	(48,500)		(32,469)	(22,245)	(38,276)
Total stockholders equity at Dec. 31, 2016	7,093,082	791	1,848,611	5,199,130	(1,094,779)	1,139,329
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	156,400
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2018 02 [Member]	17,723			(138,649)		156,372
Net Income (Loss) Attributable to Parent	1,822,181			1,822,181
Other Comprehensive Income (Loss), Net of Tax	767,930					767,930
Dividends to stockholders, $2.20 per share	(117,291)			(117,291)
Purchase of treasury stock	(43,508)				43,508
Reissuance of treasury stock	(29,418)		(22,295)	(29,106)	(36,229)
Total stockholders equity at Dec. 31, 2017	9,569,535	791	1,870,906	6,736,265	(1,102,058)	2,063,631
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	2,600
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2018 02 [Member]	(2,020)			553		(2,573)
Net Income (Loss) Attributable to Parent	715,842			715,842
Other Comprehensive Income (Loss), Net of Tax	(1,424,295)					(1,424,295)
Dividends to stockholders, $2.20 per share	(140,110)			(140,110)
Purchase of treasury stock	(299,679)				299,679
Reissuance of treasury stock	(31,280)		(27,746)	(27,601)	(31,135)
Total stockholders equity at Dec. 31, 2018	$ 8,450,553	$ 791	$ 1,898,652	$ 7,284,949	$ (1,370,602)	$ 636,763

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 2,200	$ 1,820	$ 1,560

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Cash flows from operating activities
Net Income (Loss) Attributable to Parent	$ 715,842	$ 1,822,181	$ 701,443
Change in operating assets and liabilities:
Accrued investment income	7,159	(43,142)	(18,761)
Premiums receivable and other reinsurance balances	(764,159)	(346,737)	(156,836)
Deferred policy acquisition costs	(107,325)	154,234	31,024
Reinsurance ceded receivable balances	66,298	(124,056)	(53,221)
Future policy benefits, other policy claims and benefits, and other reinsurance balances	1,593,065	1,320,810	810,474
Deferred income taxes	76,507	(847,304)	293,777
Other assets and other liabilities, net	(162,835)	242,466	(98,675)
Amortization of net investment premiums, discounts and other	(57,378)	(105,382)	(93,952)
Depreciation, Depletion and Amortization	45,127	52,902	26,853
Investment related (gains) losses, net	170,088	(167,880)	(94,195)
Excess tax benefits from share-based payment arrangement	0	0	(162)
Other, net	(1,268)	24,216	117,949
Net cash provided by operating activities	1,581,121	1,982,308	1,465,718
Cash flows from investing activities
Sales of fixed maturity securities available-for-sale	9,339,632	7,308,608	4,584,828
Principal payments on mortgage loans on real estate	626,650	589,214	472,435
Proceeds from Sale of Available-for-sale Securities, Equity	45,863	207,347	434,518
Proceeds from Sale and Collection of Mortgage Notes Receivable	445,360	339,919	442,755
Proceeds from Collection of Policy Loans	57,352	114,586	88,840
Payments to Acquire Available-for-sale Securities	(9,724,190)	(8,941,293)	(7,414,647)
Payments to Acquire Available-for-sale Securities, Equity	(13,428)	(81,254)	(584,532)
Purchases of fixed maturity securities available-for-sale	(1,019,212)	(964,421)	(1,092,876)
Payments to Fund Policy Loans	(44,708)	(44,607)	(47,646)
Cash invested in funds withheld at interest	(53,626)	(22,557)	(32,597)
Purchase of businesses, net of cash acquired of $4,988	(31,441)	0	0
Payments to Acquire Property, Plant, and Equipment	(28,891)	(44,211)	(44,642)
Change in short-term investments	129,329	52,302	465,628
Change in other invested assets	(365,242)	(121,206)	(97,790)
Net cash used in investing activities	(636,552)	(1,607,573)	(2,825,726)
Cash flows from financing activities
Dividends to stockholders	(140,110)	(117,291)	(100,371)
Repayment of collateral finance and securitization notes	(96,354)	(68,429)	(64,571)
Proceeds from long-term debt issuance	0	0	799,984
Debt issuance costs	0	0	(8,766)
Principal payments of long-term debt	(2,690)	(302,582)	(2,479)
Purchases of treasury stock	(299,679)	(43,508)	(122,916)
Excess tax benefits from share-based payment arrangement	0	0	162
Exercise of stock options, net	3,459	7,292	15,321
Change in cash collateral for derivative positions and other arrangements	43,607	(65,422)	26,413
Deposits on universal life and other investment type policies and contracts	864,193	1,017,699	1,041,623
Withdrawals on universal life and other investment type policies and contracts	(694,399)	(752,381)	(529,011)
Net cash used in financing activities	(321,973)	(324,622)	1,055,389
Effect of exchange rate changes on cash	(36,387)	52,693	(19,938)
Change in cash and cash equivalents	586,209	102,806	(324,557)
Cash and cash equivalents, beginning of period	1,303,524	1,200,718	1,525,275
Cash and cash equivalents, end of period	1,889,733	1,303,524	1,200,718
Supplementary information:
Interest paid	170,191	173,471	156,727
Income taxes paid, net of refunds	141,703	37,098	61,085
Transfer to Investments	4,636,099	3,285,837	120,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(38,350)	0	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 69,791	$ 0	$ 0

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS PARENTHETICAL - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Cash Acquired from Acquisition	$ 4,988	$ 0	$ 0

Business and Basis of Presentat

Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	BUSINESS AND BASIS OF PRESENTATION Business Reinsurance Group of America, Incorporated (“RGA”) is an insurance holding company that was formed on December 31, 1992. The consolidated financial statements herein include the assets, liabilities, and results of operations of RGA and its subsidiaries, all of which are wholly owned (collectively, the “Company”). The Company is engaged in providing traditional reinsurance, which includes individual and group life and health, disability, and critical illness reinsurance. The Company also provides financial solutions, which includes longevity reinsurance, asset-intensive products, primarily annuities, financial reinsurance and stable value products. Reinsurance is an arrangement under which an insurance company, the reinsurer, agrees to indemnify another insurance company, the ceding company, for all or a portion of the insurance risks underwritten by the ceding company. Reinsurance is designed to (i) reduce the net amount at risk on individual risks, thereby enabling the ceding company to increase the volume of business it can underwrite, as well as increase the maximum risk it can underwrite on a single risk; (ii) enhance the ceding company’s financial strength and surplus position; (iii) stabilize operating results by leveling fluctuations in the ceding company’s loss experience; and (iv) assist the ceding company in meeting applicable regulatory requirements. Basis of Presentation The consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The most significant estimates include those used in determining deferred policy acquisition costs, premiums receivable, future policy benefits, incurred but not reported claims, income taxes, valuation of investments and investment impairments, and valuation of embedded derivatives. Actual results could differ materially from the estimates and assumptions used by management. The accompanying consolidated financial statements include the accounts of RGA and its subsidiaries, all of which are wholly owned, and any variable interest entities where the Company is the primary beneficiary. Entities in which the Company has significant influence over the operating and financing decisions but are not required to be consolidated are reported under the equity method of accounting. The Company evaluates variable interest entities in accordance with the general accounting principles for Consolidation . Intercompany balances and transactions have been eliminated. There were no subsequent events, other than as disclosed in Note 19 - “Subsequent Event,” that would require disclosure or adjustments to the accompanying consolidated financial statements through the date the consolidated financial statements were issued.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES AND PRONOUNCEMENTS Investments Fixed Maturity Securities Fixed maturity securities classified as available-for-sale are reported at fair value and are so classified based upon the possibility that such securities could be sold prior to maturity if that action enables the Company to execute its investment philosophy and appropriately match investment results to operating and liquidity needs. Unrealized gains and losses on fixed maturity securities classified as available-for-sale, less applicable deferred income taxes as well as related adjustments to deferred acquisition costs, if applicable, are reflected as a direct charge or credit to accumulated other comprehensive income (“AOCI”) in stockholders’ equity on the consolidated balance sheets. Investment income is recognized as it accrues or is legally due. Realized gains and losses on sales of investments are included in investment related gains (losses), net, as are credit impairments that are other-than-temporary in nature. The cost of investments sold is primarily determined based upon the specific identification method. Equity Securities Equity securities are carried at fair value with the exception of the Company’s investment in the Federal Home Loan Bank of Des Moines (“FHLB”) common stock, which is carried at cost and included in other invested assets. Realized and unrealized gains and losses associated with equity securities carried at fair value are included in investment related gains (losses), net. Mortgage Loans on Real Estate Mortgage loans on real estate are carried at unpaid principal balances, net of any unamortized premium or discount and valuation allowances. Interest income is accrued on the principal amount of the mortgage loan based on its contractual interest rate. Amortization of premiums and discounts is recorded using the effective yield method. The Company accrues interest on loans until it is probable the Company will not receive interest or the loan is 90 days past due. Interest income, amortization of premiums, accretion of discounts and prepayment fees are reported in investment income, net of related expenses in the consolidated statements of income. A mortgage loan is considered to be impaired when, based on the current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the mortgage agreement. Although all available and applicable factors are considered in the Company’s analysis, loan-to-value and debt service coverage ratios are the most critical factors in determining impairment. Valuation allowances on mortgage loans are established based upon inherent losses expected by management to be realized in connection with future dispositions or settlement of mortgage loans, including foreclosures. The Company establishes valuation allowances for estimated impairments on an individual loan basis as of the balance sheet date. Such valuation allowances are based on the excess carrying value of the loan over the present value of expected future cash flows discounted at the loan’s original effective interest rate, the value of the loan’s collateral if the loan is in the process of foreclosure or is otherwise collateral-dependent, or the loan’s market value if the loan is being sold. Non-specific valuation allowances are established for mortgage loans based upon several loan factors, including the Company’s historical experience for loan losses, defaults and loss severity, loss expectations for loans with similar risk characteristics and industry statistics. These evaluations are revised as conditions change and new information becomes available. In addition to historical experience, management considers qualitative factors that include the impact of changing macro-economic conditions, which may not be currently reflected in the loan portfolio performance, and the quality of the loan portfolio. Any interest accrued or received on the net carrying amount of the impaired loan will be included in investment income or applied to the principal of the loan, depending on the assessment of the collectability of the loan. Mortgage loans deemed to be uncollectible or that have been foreclosed are charged off against the valuation allowances and subsequent recoveries, if any, are credited to the valuation allowances. Changes in valuation allowances are reported in investment related gains (losses), net on the consolidated statements of income. The Company evaluates whether a mortgage loan modification represents a troubled debt restructuring. In a troubled debt restructuring, the Company grants concessions related to the borrower’s financial difficulties. Generally, the types of concessions include: reduction of the contractual interest rate, extension of the maturity date at an interest rate lower than current market interest rates and/or a reduction of accrued interest. The Company considers the amount, timing and extent of the concession granted in determining any impairment or changes in the specific valuation allowance recorded in connection with the troubled debt restructuring. Through the continuous monitoring process, the Company may have recorded a specific valuation allowance prior to when the mortgage loan is modified in a troubled debt restructuring. Accordingly, the carrying value (after specific valuation allowance) before and after modification through a troubled debt restructuring may not change significantly, or may increase if the expected recovery is higher than the pre-modification recovery assessment. Policy Loans Policy loans are reported at the unpaid principal balance. Interest income on such loans is recorded as earned using the contractually agreed-upon interest rate. These policy loans present no credit risk because the amount of the loan cannot exceed the obligation due the ceding company upon the death of the insured or surrender of the underlying policy. Funds Withheld at Interest Funds withheld at interest represent amounts contractually withheld by ceding companies in accordance with reinsurance agreements. For agreements written on a modified coinsurance (“modco”) basis and agreements written on a coinsurance funds withheld basis, assets that support the net statutory reserves or as defined in the treaty, are withheld and legally owned by the ceding company. Interest, recorded in investment income, net of related expenses in the consolidated statements of income, accrues to these assets at calculated rates as defined by the treaty terms. Changes in the value of the equity options held within the funds withheld portfolio associated with equity-indexed annuity treaties are reflected in investment income, net of related expenses. Short-term Investments Short-term investments represent investments with remaining maturities of one year or less, but greater than three months, at the time of acquisition and are stated at estimated fair value or amortized cost, which approximates estimated fair value. Interest on short-term investments is recorded in investment income, net of related expenses in the consolidated statements of income. Other Invested Assets In addition to FHLB common stock discussed in the Equity Securities section above and derivative contracts discussed below, other invested assets include limited partnership interests, joint ventures (other than operating joint ventures), equity release mortgages and contractholder-directed investments. Limited partnership interests are primarily carried at cost. Based on the nature and structure of these investments, they do not meet the characteristics of an equity security in accordance with applicable accounting standards. Joint ventures and certain limited partnerships are reported using the equity method of accounting. Equity release mortgages are carried at unpaid principal balances, net of any unamortized premium or discount and valuation allowance. Interest income is accrued on the principal amount of the equity release mortgage based on its contractual interest rate. The fair value option (“FVO”) was elected for contractholder-directed investments supporting unit-linked variable annuity type liabilities that do not qualify for presentation and reporting as separate accounts. Changes in estimated fair value of these securities are included in investment income, net of related expenses. Securities Borrowing, Lending and Repurchase Agreements The Company participates in securities borrowing programs whereby securities, which are not reflected on the Company’s consolidated balance sheets, are borrowed from third parties. The borrowed securities are used to provide collateral under affiliated reinsurance transactions. The Company is required to maintain a minimum of 100% of the fair value, or par value under certain programs, of the borrowed securities as collateral. The collateral consists of rights to reinsurance treaty cash flows. If cash flows from the reinsurance treaties are insufficient to maintain the minimum collateral requirement, the Company may substitute cash or securities to meet the requirement. The Company participates in a securities lending program whereby securities, reflected as investments on the Company’s consolidated balance sheets, are loaned to a third party. The Company receives securities as collateral, in an amount equal to a minimum of 105% of the fair value of the securities lent. The securities received as collateral are not reflected on the Company’s consolidated balance sheets. The Company participates in a repurchase program in which securities, reflected as investments on the Company’s consolidated balance sheets, are pledged to a third party. In return, the Company receives cash from the third party, which is reflected as a payable to a third party, included in other liabilities on the consolidated balance sheets. The Company is required to maintain a minimum collateral balance with a fair value of 105% of the cash received. The Company participates in repurchase/reverse repurchase programs in which securities, reflected as investments on the Company’s consolidated balance sheets, are pledged to third parties. In return, the Company receives securities from the third parties with an estimated fair value equal to a minimum of 100% of the securities pledged. The securities received are not reflected on the Company’s consolidated balance sheets. Other-than-Temporary Impairment The Company identifies fixed maturity securities that could potentially have credit impairments that are other-than-temporary by monitoring market events that could impact issuers’ credit ratings, business climates, management changes, litigation, government actions and other similar factors. The Company also monitors late payments, pricing levels, rating agency actions, key financial ratios, financial statements, revenue forecasts and cash flow projections as indicators of credit issues. The Company reviews all securities on a case-by-case basis to determine whether an other-than-temporary decline in value exists and whether losses should be recognized. The Company considers relevant facts and circumstances in evaluating whether a credit or interest rate-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 or amortized cost; (2) the reasons for the decline in fair value; (3) the issuer’s financial position and access to capital; and (4) the Company’s intent to sell a security or whether it is more likely than not it will be required to sell the security before the recovery of its amortized cost that, in some cases, may extend to maturity. To the extent the Company determines that a security is deemed to be other-than-temporarily impaired, an impairment loss is recognized. Impairment losses on fixed maturity securities recognized in the financial statements are dependent on the facts and circumstances related to the specific security. If the Company intends to sell a security or it is more likely than not that it would be required to sell a security before the recovery of its amortized cost, less any recorded credit loss, it recognizes an other-than-temporary impairment in investment related gains (losses), net on the consolidated statements of income for the difference between amortized cost and fair value. If neither of these two conditions exists then the recognition of the other-than-temporary impairment is bifurcated and the Company recognizes the credit loss portion in investment related gains (losses), net and the non-credit loss portion in AOCI. The Company estimates 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 techniques and assumptions for establishing the best estimate cash flows vary depending on the type of security. The asset-backed securities’ 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 fixed maturity security cash flow estimates are derived from scenario-based outcomes of expected corporate restructurings or the disposition of assets using security specific facts and circumstances including timing, security interests and loss severity. In periods after an other-than-temporary impairment loss is recognized on a fixed maturity security, the Company will report the impaired security as if it had been purchased on the date it was impaired and will continue to estimate the present value of the estimated cash flows of the security. Accordingly, the discount (or reduced premium) based on the new cost basis is accreted into net investment income over the remaining term of the fixed maturity security in a prospective manner based on the amount and timing of estimated future cash flows. The Company considers its cost method investments for other-than-temporary impairment when the carrying value of these investments exceeds the net asset value. The Company takes into consideration the severity and duration of this excess when deciding if the cost method investment is other-than-temporarily impaired. For equity method investments (including real estate joint ventures), the Company considers financial and other information provided by the investee, other known information and inherent risks in the underlying investments, as well as future capital commitments, in determining whether an impairment has occurred. Derivative Instruments Overview The Company utilizes a variety of derivative instruments including swaps, options, forwards and futures, primarily to manage or hedge interest rate risk, credit risk, inflation risk, foreign currency risk, market volatility and various other market risks associated with its business. The Company does not invest in derivatives for speculative purposes. It is the Company’s policy to enter into derivative contracts primarily with highly rated parties. See Note 5 - “Derivative Instruments” for additional detail on the Company’s derivative positions. Accounting and Financial Statement Presentation of Derivatives Derivatives are carried on the Company’s consolidated balance sheets primarily in other invested assets or other liabilities, at fair value. Certain derivatives are subject to master netting provisions and reported as a net asset or liability. On the date a derivative contract is executed, the Company designates the derivative as (1) a fair value hedge, (2) a cash flow hedge, (3) a net investment hedge in a foreign operation or (4) free-standing derivatives held for other risk management purposes, which primarily involve managing asset or liability risks associated with the Company’s reinsurance treaties that do not qualify for hedge accounting. Changes in the fair value of free-standing derivative instruments, which do not receive accounting hedge treatment, are primarily reflected in investment related gains (losses), net. Changes in the fair value of non-investment free-standing derivative instruments (e.g. mortality and longevity swaps), which do not receive accounting hedge treatment, are reflected in other revenues. Hedge Documentation and Hedge Effectiveness To qualify for hedge accounting, at the inception of the hedging relationship, the Company formally documents its risk management objective and strategy for undertaking the hedging transaction, as well as its designation of the hedge as either (i) a fair value hedge; (ii) a cash flow hedge; or (iii) a hedge of a net investment in a foreign operation. In this documentation, the Company sets forth how the hedging instrument is expected to hedge the designated risks related to the hedged item and sets forth the method that will be used to retrospectively and prospectively assess the hedging instrument’s effectiveness and the method that will be used to measure ineffectiveness. A derivative designated as a hedging instrument must be assessed as being highly effective in offsetting the designated risk of the hedged item. Hedge effectiveness is formally assessed at inception and periodically throughout the life of the designated hedging relationship. Under a fair value hedge, changes in the fair value of the hedging derivative, including amounts measured as ineffective, and changes in the fair value of the hedged item related to the designated risk being hedged, are reported within investment related gains (losses), net. The fair values of the hedging derivatives are exclusive of any accruals that are separately reported in the consolidated statements of income within interest income or interest expense to match the location of the hedged item. Under a cash flow hedge, changes in the fair value of the hedging derivative measured as effective are reported within AOCI and the deferred gains or losses on the derivative are reclassified into the consolidated statements of income when the Company’s earnings are affected by the variability in cash flows of the hedged item. Changes in the fair value of the hedging instrument measured as ineffective are reported within investment related gains (losses), net. The fair values of the hedging derivatives are exclusive of any accruals that are separately reported in the consolidated statements of income within interest income or interest expense to match the location of the hedged item. In a hedge of a net investment in a foreign operation, changes in the fair value of the hedging derivative that are measured as effective are reported within AOCI consistent with the translation adjustment for the hedged net investment in the foreign operation. Changes in the fair value of the hedging instrument measured as ineffective are reported within investment related gains (losses), net. The Company discontinues hedge accounting prospectively when: (i) it is determined that the derivative is no longer highly effective in offsetting changes in the estimated fair value or cash flows of a hedged item; (ii) the derivative expires, is sold, terminated, or exercised; (iii) it is no longer probable that the hedged forecasted transaction will occur; or (iv) the derivative is de-designated as a hedging instrument. When hedge accounting is discontinued because it is determined that the derivative is not highly effective, the derivative continues to be carried in the consolidated balance sheets at fair value, with changes in fair value recognized in investment related gains (losses), net. The carrying value of the hedged asset or liability under a fair value hedge is no longer adjusted for changes in its estimated fair value due to the hedged risk, and the cumulative adjustment to its carrying value is amortized into income over the remaining life of the hedged item. Provided the hedged forecasted transaction occurrence is still probable, the changes in estimated fair value of derivatives recorded in other comprehensive income (loss) (“OCI”) related to discontinued cash flow hedges are released into the consolidated statements of income when the Company’s earnings are affected by the variability in cash flows of the hedged item. When hedge accounting is discontinued because it is no longer probable that the forecasted transactions will occur on the anticipated date or within two months of that date, the derivative continues to be carried in the consolidated balance sheets at its estimated fair value, with changes in estimated fair value recognized currently in investment related gains (losses), net. Deferred gains and losses of a derivative recorded in OCI pursuant to the discontinued cash flow hedge of a forecasted transaction that is no longer probable are recognized immediately in investment related gains (losses), net. In all other situations in which hedge accounting is discontinued, the derivative is carried at its estimated fair value in the consolidated balance sheets, with changes in its estimated fair value recognized in the current period as investment related gains (losses), net. Embedded Derivatives The Company reinsures certain annuity products that contain terms that are deemed to be embedded derivatives, primarily equity-indexed annuities and variable annuities with guaranteed minimum benefits. The Company assesses reinsurance contract terms to identify embedded derivatives, which are required to be bifurcated under the general accounting principles for Derivatives and Hedging . If the contract is not reported for in its entirety at fair value and it is determined that the terms of the embedded derivative are not clearly and closely related to the economic characteristics of the host contract, and that a separate instrument with the same terms would qualify as a derivative instrument, the embedded derivative is bifurcated from the host contract and accounted for separately. Such embedded derivatives are carried on the consolidated balance sheets at fair value in the same line item as the host contract. Changes in the fair value of embedded derivatives associated with equity-indexed annuities are reflected in interest credited on the consolidated statements of income and changes in the fair value of embedded derivatives associated with variable annuity guaranteed minimum benefits are reflected in investment related gains (losses), net on the consolidated statements of income. See “Interest-Sensitive Contract Liabilities” below for additional information on embedded derivatives related to equity-indexed and variable annuities. The Company has implemented an economic hedging strategy to mitigate the volatility associated with its reinsurance of variable annuity guaranteed minimum benefits. The hedging strategy is designed such that changes in the fair value of the hedge contracts, primarily futures, swap contracts and options, move in the opposite direction of changes in the fair value of the embedded derivatives. While the Company actively manages its hedging program, the hedges that are in place may not be totally effective in offsetting the embedded derivative changes due to the many variables that must be managed and the Company may see a corresponding increase or decrease in the net liability. The Company has elected not to assess this hedging strategy for hedge accounting treatment. Additionally, reinsurance treaties written on a modco or funds withheld basis are subject to the general accounting principles for Derivatives and Hedging related to embedded derivatives. The Company’s funds withheld at interest balances are primarily associated with its reinsurance treaties structured on a modco or funds withheld basis, the majority of which were subject to the general accounting principles for Derivatives and Hedging related to embedded derivatives. Management believes the embedded derivative feature in each of these reinsurance treaties is similar to a total return swap on the assets held by the ceding companies. The valuation of embedded derivatives is sensitive to the investment credit spread environment. Changes in investment credit spreads are also affected by the application of a credit valuation adjustment (“CVA”). The fair value calculation of an embedded derivative in an asset position utilizes a CVA based on the ceding company’s credit risk. Conversely, the fair value calculation of an embedded derivative in a liability position utilizes a CVA based on the Company’s credit risk. Generally, an increase in investment credit spreads, ignoring changes in the CVA, will have a negative impact on the fair value of the embedded derivative (decrease in income). The fair value of the embedded derivatives is included in the funds withheld at interest line item on the consolidated balance sheets. The change in the fair value of the embedded derivatives is recorded in investment related gains (losses), net on the consolidated statements of income. The Company has entered into various financial reinsurance treaties on a funds withheld and modco basis. These treaties do not transfer significant insurance risk and are recorded on a deposit method of accounting with the Company earning a net fee. As a result of the experience refund provisions contained in these treaties, the value of the embedded derivatives in these contracts is currently considered immaterial. The Company monitors the performance of these treaties on a quarterly basis. Significant adverse performance or losses on these treaties may result in a loss associated with the embedded derivative. Fair Value Measurements General accounting principles for Fair Value Measurements and Disclosures define fair value, establish a framework for measuring fair value, establish a fair value hierarchy based on the inputs used to measure fair value and enhance disclosure requirements for fair value measurements. In compliance with these principles, the Company has categorized its assets and liabilities, based on the priority of the inputs to the valuation technique, into a three level hierarchy or separately for assets measured using the net asset value (“NAV”). The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1), the second highest priority to quoted prices in markets that are not active or inputs that are observable either directly or indirectly (Level 2) and the lowest priority to unobservable inputs (Level 3). If the inputs used to measure fair value fall within different levels of the hierarchy, the category level is based on the lowest priority level input that is significant to the fair value measurement of the asset or liability. See Note 6 - “Fair Value of Assets and Liabilities” for further details on the Company’s assets and liabilities recorded at fair value. Cash and Cash Equivalents Cash and cash equivalents include cash on deposit and highly liquid debt instruments purchased with an original maturity of three months or less. Premiums Receivable Premiums are accrued when due and in accordance with information received from the ceding company. When the Company enters into a new reinsurance agreement, it records accruals based on the terms of the reinsurance treaty. Similarly, when a ceding company fails to report information on a timely basis, the Company records accruals based on the terms of the reinsurance treaty as well as historical experience. Other management estimates include adjustments for increased in force on existing treaties, lapsed premiums given historical experience, the financial health of specific ceding companies, collateral value and the legal right of offset on related amounts (i.e. allowances and claims) owed to the ceding company. Under the legal right of offset provisions in its reinsurance treaties, the Company can withhold payments for allowances and claims from unpaid premiums. Based on its review of these factors and historical experience, the Company did not believe a provision for doubtful accounts was necessary as of December 31, 2018 or 2017 . Reinsurance Ceded Receivables The Company generally reports retrocession activity on a gross basis. Amounts paid or deemed to have been paid for reinsurance are reflected in reinsurance ceded receivables. The cost of reinsurance related to long-duration contracts is recognized over the terms of the reinsured policies on a basis consistent with the reporting of those policies. Deferred Policy Acquisition Costs Costs of acquiring new business, which vary with and are directly related to the production of new business, have been deferred to the extent that such costs are deemed recoverable from future premiums or gross profits. Such costs include commissions and allowances as well as certain costs of policy issuance and underwriting. Non-commission costs related to the acquisition of new and renewal insurance contracts may be deferred only if they meet the following criteria: • Incremental direct costs of a successful contract acquisition • Portions of employees’ salaries and benefits directly related to time spent performing specified acquisition activities for a contract that has been acquired or renewed • Other costs directly related to the specified acquisition or renewal activities that would not have been incurred had that acquisition contract transaction not occurred The Company tests the recoverability for each year of business at issue before establishing additional deferred acquisition costs (“DAC”). The Company also performs annual tests to establish that DAC are expected to remain recoverable, and if financial performance significantly deteriorates to the point where a deficiency exists, a cumulative charge to current operations will be recorded. No such adjustments related to DAC recoverability were made in 2018, 2017 and 2016 . DAC related to traditional life insurance contracts are amortized with interest over the premium-paying period of the related policies in proportion to the ratio of individual period premium revenues to total anticipated premium revenues over the life of the policy. Such anticipated premium revenues are estimated using the same assumptions used for computing liabilities for future policy benefits. DAC related to interest-sensitive life and investment-type policies are amortized over the lives of the policies, in proportion to the gross profits realized from mortality, investment income less interest credited, and expense margins. Other Reinsurance Balances The Company assumes and retrocedes financial reinsurance contracts that do not expose it to a reasonable possibility of loss from insurance risk. These contracts are reported as deposits and are included in other reinsurance assets/liabilities. The amount of revenue reported in other revenues on these contracts represents fees and the cost of insurance under the terms of the reinsurance agreement. Assets and liabilities are reported on a net or gross basis, depending on the specific details within each treaty. Reinsurance agreements reported on a net basis, where a legal right of offset exists, are generally included in other reinsurance balances on the consolidated balance sheets. Balances resulting from the assumption and/or subsequent transfer of benefits and obligations resulting from cash flows related to variable annuities have also been classified as other reinsurance balance assets and/or liabilities. Other reinsurance assets are included in premiums receivable and other reinsurance balances while other reinsurance liabilities are included in other reinsurance balances on the consolidated balance sheets. Acquired Intangibles Goodwill and Value of Business Acquired Goodwill, reported in other assets, is not amortized into results of operations, but instead is reviewed at least annually for impairment and written down only in the periods in which the recorded value of goodwill exceeds its fair value. Goodwill as of December 31, 2018 and 2017 totaled $7.0 million . The value of business acquired (“VOBA”) is amortized in proportion to the ratio of annual premium revenues to total anticipated premium revenues or in relation to the present value of estimated profits. Anticipated premium revenues have been estimated using assumptions consistent with those used in estimating reserves for future policy benefits. The ca

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following table sets forth the computation of basic and diluted earnings per share on net income (in thousands, except per share information): 2018 2017 2016 Earnings: Net income (numerator for basic and diluted calculations) $ 715,842 $ 1,822,181 $ 701,443 Shares: Weighted average outstanding shares (denominator for basic calculations) 63,658 64,427 64,274 Equivalent shares from outstanding stock options 1,436 1,326 715 Diluted shares (denominator for diluted calculations) 65,094 65,753 64,989 Earnings per share: Basic $ 11.25 $ 28.28 $ 10.91 Diluted 11.00 27.71 10.79 The calculation of common equivalent shares does not include the impact of options having a strike or conversion price that exceeds the average stock price for the earnings period, as the result would be antidilutive. The calculation of common equivalent shares also excludes the impact of outstanding performance contingent shares, as the conditions necessary for their issuance have not been satisfied as of the end of the reporting period. Approximately 0.1 million and 0.2 million outstanding stock options were not included in the calculation of common equivalent shares during 2018 and 2017, respectively. During 2016, all outstanding options were included in the calculation of common equivalent shares. Approximately 0.4 million , 0.3 million and 0.4 million performance contingent shares were excluded from the calculation of common equivalent shares during 2018 , 2017 and 2016 , respectively.

Investments

Investments	12 Months Ended
	Dec. 31, 2018
Investments [Abstract]
Investments	INVESTMENTS Fixed Maturity and Equity Securities Available-for-Sale The Company holds various types of fixed maturity securities available-for-sale and classifies them as corporate securities (“Corporate”), Canadian and Canadian provincial government securities (“Canadian government”), residential mortgage-backed securities (“RMBS”), asset-backed securities (“ABS”), commercial mortgage-backed securities (“CMBS”), U.S. government and agencies (“U.S. government”), state and political subdivisions, and other foreign government, supranational and foreign government-sponsored enterprises (“Other foreign government”). The following table provides information relating to investments in fixed maturity securities by sector as of December 31, 2018 (dollars in thousands): December 31, 2018: Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value % of Total Other-than- temporary impairments in AOCI Available-for-sale: Corporate $ 24,006,407 $ 530,804 $ 555,092 $ 23,982,119 59.9 % $ — Canadian government 2,768,466 1,126,227 2,308 3,892,385 9.7 — RMBS 1,872,236 22,267 25,282 1,869,221 4.7 — ABS 2,171,254 10,779 32,829 2,149,204 5.4 275 CMBS 1,428,115 9,153 18,234 1,419,034 3.5 — U.S. government 2,233,537 10,204 57,867 2,185,874 5.5 — State and political subdivisions 721,290 39,914 9,010 752,194 1.9 — Other foreign government 3,680,863 109,320 47,868 3,742,315 9.4 — Total fixed maturity securities $ 38,882,168 $ 1,858,668 $ 748,490 $ 39,992,346 100.0 % $ 275 The following table provides information relating to investments in fixed maturity and equity securities by sector as of December 31, 2017 (dollars in thousands): December 31, 2017: Amortized Unrealized Unrealized Estimated % of Total Other-than- Available-for-sale: Corporate $ 21,966,803 $ 1,299,594 $ 55,429 $ 23,210,968 60.9 % $ — Canadian government 2,843,273 1,378,510 1,707 4,220,076 11.1 — RMBS 1,695,126 36,632 11,878 1,719,880 4.5 — ABS 1,634,758 18,798 5,194 1,648,362 4.3 275 CMBS 1,285,594 22,627 4,834 1,303,387 3.4 — U.S. government 1,953,436 12,089 21,933 1,943,592 5.1 — State and political subdivisions 647,727 59,997 4,296 703,428 1.8 — Other foreign government 3,254,695 154,507 8,075 3,401,127 8.9 — Total fixed maturity securities $ 35,281,412 $ 2,982,754 $ 113,346 $ 38,150,820 100.0 % $ 275 Non-redeemable preferred stock $ 41,553 $ 479 $ 2,226 $ 39,806 39.7 % Other equity securities 61,288 479 1,421 60,346 60.3 Total equity securities $ 102,841 $ 958 $ 3,647 $ 100,152 100.0 % The Company enters into various collateral arrangements with counterparties that require both the pledging and acceptance of fixed maturity securities as collateral. Pledged fixed maturity securities are included in fixed maturity securities, available-for-sale in the consolidated balance sheets. Fixed maturity securities received as collateral are held in separate custodial accounts and are not recorded on the Company’s consolidated balance sheets. Subject to certain constraints, the Company is permitted by contract to sell or repledge collateral it receives; however, as of December 31, 2018 and 2017 , none of the collateral received had been sold or repledged. The Company also holds assets in trust to satisfy collateral requirements under derivative transactions and certain third-party reinsurance treaties. The following table includes fixed maturity securities pledged and received as collateral and assets in trust held to satisfy collateral requirements under derivative transactions and certain third-party reinsurance treaties as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Fixed maturity securities pledged as collateral $ 80,891 $ 83,950 $ 72,542 $ 75,622 Fixed maturity securities received as collateral n/a 616,584 n/a 590,417 Assets in trust held to satisfy collateral requirements 20,072,735 20,366,170 15,584,296 16,715,281 The Company monitors its concentrations of financial instruments on an ongoing basis and mitigates credit risk by maintaining a diversified investment portfolio that limits exposure to any one issuer. The Company’s exposure to concentrations of credit risk from single issuers greater than 10% of the Company’s stockholders’ equity included securities of the U.S. government and its agencies, as well as the securities disclosed below, as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Fixed maturity securities guaranteed or issued by: Canadian province of Quebec $ 1,091,018 $ 1,757,087 $ 1,119,337 $ 1,917,996 Canadian province of Ontario 913,642 1,187,526 939,837 1,282,944 The amortized cost and estimated fair value of fixed maturity securities classified as available-for-sale as of December 31, 2018 are shown by contractual maturity in the table below (dollars in thousands). Actual maturities can differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Asset and mortgage-backed securities are shown separately in the table below, as they are not due at a single maturity date. Amortized Cost Estimated Fair Value Available-for-sale: Due in one year or less $ 1,185,868 $ 1,190,931 Due after one year through five years 8,760,200 8,851,307 Due after five years through ten years 9,060,972 9,149,497 Due after ten years 14,403,523 15,363,152 Asset and mortgage-backed securities 5,471,605 5,437,459 Total $ 38,882,168 $ 39,992,346 Corporate Fixed Maturity Securities The tables below show the major industry types of the Company’s corporate fixed maturity holdings as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018: Amortized Cost Estimated Fair Value % of Total Finance $ 8,793,742 $ 8,730,568 36.3 % Industrial 12,336,857 12,342,111 51.6 Utility 2,875,808 2,909,440 12.1 Total $ 24,006,407 $ 23,982,119 100.0 % December 31, 2017: Amortized Cost Estimated Fair Value % of Total Finance $ 7,977,885 $ 8,362,774 36.1 % Industrial 11,535,166 12,199,333 52.5 Utility 2,453,752 2,648,861 11.4 Total $ 21,966,803 $ 23,210,968 100.0 % Other-Than-Temporary Impairments—Fixed Maturity Securities As discussed in Note 2 – “Significant Accounting Policies and Pronouncements,” a portion of certain other-than-temporary impairment (“OTTI”) losses on fixed maturity securities is recognized in AOCI. For these securities, the net amount recognized in the consolidated statements of income (“credit loss impairments”) represents the difference between the amortized cost of the security and the net present value of its projected future cash flows discounted at the effective interest rate implicit in the debt security prior to impairment. Any remaining difference between the fair value and amortized cost is recognized in AOCI. The following table sets forth the amount of pre-tax credit loss impairments on fixed maturity securities held by the Company as of the dates indicated, for which a portion of the OTTI loss was recognized in AOCI, and the corresponding changes in such amounts (dollars in thousands): 2018 2017 2016 Balance, beginning of period $ 3,677 $ 6,013 $ 7,284 Additional impairments - credit loss OTTI recognized on securities previously impaired — — 231 Credit loss impairments previously recognized on securities impaired to fair value during the period — (2,336 ) — Credit loss previously recognized on securities that matured, paid down, prepaid or were sold during the period — — (1,502 ) Balance, end of period $ 3,677 $ 3,677 $ 6,013 Unrealized Losses for Fixed Maturity and Equity Securities Available-for-Sale The following table presents the total gross unrealized losses for the 3,109 fixed maturity securities as of December 31, 2018, where the estimated fair value had declined and remained below amortized cost by the indicated amount (dollars in thousands): 2018 Gross Unrealized Losses % of Total Less than 20% $ 721,015 96.3 % 20% or more for less than six months 21,336 2.9 20% or more for six months or greater 6,139 0.8 Total $ 748,490 100.0 % The following table presents the total gross unrealized losses for the 1,116 fixed maturity and equity securities as of December 31, 2017, where the estimated fair value had declined and remained below amortized cost by the indicated amount (dollars in thousands): 2017 Gross Unrealized Losses % of Total Less than 20% $ 113,466 97.0 % 20% or more for less than six months 689 0.6 20% or more for six months or greater 2,838 2.4 Total $ 116,993 100.0 % The Company’s determination of whether a decline in value is other-than-temporary includes an analysis of the underlying credit and the extent and duration of a decline in value. The Company’s credit analysis of an investment includes determining whether the issuer is current on its contractual payments, evaluating whether it is probable that the Company will be able to collect all amounts due according to the contractual terms of the security and analyzing the overall ability of the Company to recover the amortized cost of the investment. In the Company’s impairment review process, the duration and severity of an unrealized loss position for equity securities are given greater weight and consideration given the lack of contractual cash flows or deferability features. The following table presents the estimated fair values and gross unrealized losses, including other-than-temporary impairment losses reported in AOCI, for 3,109 fixed maturity securities that have estimated fair values below amortized cost as of December 31, 2018 (dollars in thousands). These investments are presented by class and grade of security, as well as the length of time the related fair value has remained below amortized cost. Less than 12 months 12 months or greater Total December 31, 2018: Estimated Fair Value Gross Unrealized Losses Estimated Gross Estimated Gross Investment grade securities: Corporate $ 8,505,371 $ 302,604 $ 3,611,266 $ 195,082 $ 12,116,637 $ 497,686 Canadian government 25,169 419 131,806 1,612 156,975 2,031 RMBS 269,558 2,488 836,741 22,760 1,106,299 25,248 ABS 1,102,677 24,271 381,609 8,523 1,484,286 32,794 CMBS 384,259 4,304 414,719 13,930 798,978 18,234 U.S. government 8,616 80 1,086,694 57,787 1,095,310 57,867 State and political subdivisions 103,504 1,538 157,330 7,472 260,834 9,010 Other foreign government 789,859 24,509 472,934 17,446 1,262,793 41,955 Total investment grade securities 11,189,013 360,213 7,093,099 324,612 18,282,112 684,825 Below investment grade securities: Corporate 755,679 42,760 122,559 14,646 878,238 57,406 Canadian government 443 34 1,770 243 2,213 277 RMBS — — 1,026 34 1,026 34 ABS — — 1,063 35 1,063 35 Other foreign government 128,725 5,574 7,479 339 136,204 5,913 Total below investment grade securities 884,847 48,368 133,897 15,297 1,018,744 63,665 Total fixed maturity securities $ 12,073,860 $ 408,581 $ 7,226,996 $ 339,909 $ 19,300,856 $ 748,490 The following table presents the estimated fair values and gross unrealized losses, including other-than-temporary impairment losses reported in AOCI, for 1,116 fixed maturity and equity securities that have estimated fair values below amortized cost as of December 31, 2017 (dollars in thousands): Less than 12 months 12 months or greater Total December 31, 2017: Estimated Gross Estimated Gross Estimated Gross Investment grade securities: Corporate $ 1,886,212 $ 17,099 $ 1,009,750 $ 28,080 $ 2,895,962 $ 45,179 Canadian government 18,688 91 111,560 1,596 130,248 1,687 RMBS 566,699 5,852 224,439 6,004 791,138 11,856 ABS 434,274 2,707 168,524 2,434 602,798 5,141 CMBS 220,401 1,914 103,269 2,920 323,670 4,834 U.S. government 800,298 6,177 767,197 15,756 1,567,495 21,933 State and political subdivisions 43,510 242 68,666 4,054 112,176 4,296 Other foreign government 369,717 2,707 191,265 4,704 560,982 7,411 Total investment grade securities 4,339,799 36,789 2,644,670 65,548 6,984,469 102,337 Below investment grade securities: Corporate 194,879 3,317 75,731 6,933 270,610 10,250 Canadian government 1,995 20 — — 1,995 20 RMBS — — 1,369 22 1,369 22 ABS — — 1,489 53 1,489 53 Other foreign government 28,600 113 15,134 551 43,734 664 Total below investment grade securities 225,474 3,450 93,723 7,559 319,197 11,009 Total fixed maturity securities $ 4,565,273 $ 40,239 $ 2,738,393 $ 73,107 $ 7,303,666 $ 113,346 Non-redeemable preferred stock $ 82 $ 1 $ 26,471 $ 2,225 $ 26,553 $ 2,226 Other equity securities 5,820 1,023 47,251 398 53,071 1,421 Total equity securities $ 5,902 $ 1,024 $ 73,722 $ 2,623 $ 79,624 $ 3,647 The Company has no intention to sell, nor does it expect to be required to sell, the securities outlined in the table above, as of the dates indicated. However, unforeseen facts and circumstances may cause the Company to sell fixed maturity securities in the ordinary course of managing its portfolio to meet certain diversification, credit quality and liquidity guidelines. Changes in unrealized losses are primarily driven by changes in interest rates. Investment Income, Net of Related Expenses Major categories of investment income, net of related expenses, consist of the following (dollars in thousands): 2018 2017 2016 Fixed maturity securities available-for-sale $ 1,528,086 $ 1,401,585 $ 1,285,406 Equity securities 4,343 4,445 12,513 Mortgage loans on real estate 214,387 197,755 168,582 Policy loans 59,332 60,617 63,837 Funds withheld at interest 309,977 457,774 368,728 Short-term investments and cash and cash equivalents 14,349 7,171 8,051 Other invested assets 98,557 106,015 76,858 Investment income 2,229,031 2,235,362 1,983,975 Investment expense (90,506 ) (80,711 ) (72,089 ) Investment income, net of related expenses $ 2,138,525 $ 2,154,651 $ 1,911,886 Investment Related Gains (Losses), Net Investment related gains (losses), net, consist of the following (dollars in thousands): 2018 2017 2016 Fixed maturity securities available-for-sale: Other-than-temporary impairment losses $ (28,494 ) $ (42,639 ) $ (38,805 ) Portion of loss recognized in accumulated other comprehensive income — — 74 Gain on investment activity 65,211 110,546 145,172 Loss on investment activity (158,870 ) (37,328 ) (47,094 ) Equity securities: Other-than-temporary impairment losses — (1,202 ) — Gain on investment activity 4,429 23 9,198 Loss on investment activity (1,937 ) (4,351 ) (2,871 ) Change in unrealized gains (losses) recognized in earnings (23,184 ) — — Other impairment losses and change in mortgage loan provision (11,919 ) (9,497 ) (11,006 ) Derivatives and other, net (15,324 ) 152,328 39,527 Total investment related gains (losses), net $ (170,088 ) $ 167,880 $ 94,195 The other-than-temporary impairment losses on fixed maturity securities for 2018, 2017 and 2016 are primarily due to emerging market and high-yield debt exposures. The fluctuations in investment related gains (losses) for derivatives and other are primarily due to changes in the fair value of embedded derivatives related to modco and funds withheld treaties, as a result of changes in interest rates, driven primarily by credit spreads. These fluctuations were partially offset by changes in the fair value of free-standing derivatives as a result of changes in value of underlying stock indices, movements in credit and inflation spreads, and changes in interest rates. As of December 31, 2018 and 2017 , the Company held non-income producing securities with amortized costs of $41.3 million and $38.8 million , and estimated fair values of $42.7 million and $39.3 million , respectively. Generally, securities are non-income producing when principal or interest is not paid primarily as a result of bankruptcies or credit defaults, but also include securities where amortization has been discontinued. During 2018, 2017 and 2016 , the Company sold fixed maturity securities with fair values of $5,784.6 million , $2,550.1 million , and $1,055.5 million at losses of $158.9 million , $37.3 million and $47.1 million , respectively. During 2018, 2017 and 2016 , the Company sold equity securities with fair values of $32.8 million , $177.7 million , and $126.1 million at losses of $1.9 million , $4.4 million and $2.9 million , respectively. The Company generally does not engage in short-term buying and selling of securities. Securities Borrowing, Lending and Repurchase Agreements The following table includes the amount of borrowed securities, securities lent and securities collateral received as part of the securities lending program, repurchased/reverse repurchased securities pledged and received and cash received as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Borrowed securities $ 335,781 $ 366,663 $ 358,875 $ 377,820 Securities lending: Securities loaned 101,981 102,618 117,246 121,551 Securities received n/a 112,000 n/a 128,000 Repurchase program/reverse repurchase program: Securities pledged 554,806 554,589 413,819 428,344 Securities received n/a 530,932 n/a 417,550 The Company also held cash collateral for securities lending and the repurchase program/reverse repurchase programs of $28.6 million and $31.2 million as of December 31, 2018 and 2017 , respectively. No cash or securities have been pledged by the Company for its securities borrowing program as of December 31, 2018 and 2017 . The following tables present information on the Company’s securities lending and repurchase transactions as of December 31, 2018 and 2017 , respectively (dollars in thousands). Collateral associated with certain borrowed securities is not included within the tables as the collateral pledged to each counterparty is the right to reinsurance treaty cash flows. December 31, 2018 Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total Securities lending transaction: Corporate $ — $ — $ — $ 102,618 $ 102,618 Total — — — 102,618 102,618 Repurchase transactions: Corporate — — — 254,151 254,151 U.S. government — — — 221,572 221,572 Foreign government — — — 78,866 78,866 Total — — — 554,589 554,589 Total transactions $ — $ — $ — $ 657,207 $ 657,207 Gross amount of recognized liabilities for securities lending and repurchase transactions in preceding table $ 671,492 Amounts related to agreements not included in offsetting disclosure $ 14,285 December 31, 2017 Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total Securities lending transaction: Corporate $ — $ — $ — $ 121,551 $ 121,551 Total — — — 121,551 121,551 Repurchase transactions: Corporate — — 312 184,334 $ 184,646 U.S. government — — — 220,765 220,765 Foreign government — — — 21,802 21,802 Other 1,131 — — — 1,131 Total 1,131 — 312 426,901 428,344 Total transactions $ 1,131 $ — $ 312 $ 548,452 $ 549,895 Gross amount of recognized liabilities for repurchase transactions in preceding table $ 576,786 Amounts related to agreements not included in offsetting disclosure $ 26,891 The Company has elected to offset amounts recognized as receivables and payables resulting from the repurchase/reverse repurchase programs. After the effect of offsetting, the net amount presented on the consolidated balance sheets was a liability of $0.4 million and $1.1 million as of December 31, 2018 and 2017 , respectively. As of December 31, 2018 and 2017 , the Company recognized payables resulting from cash received as collateral associated with a repurchase agreement as discussed above. Amounts owed to and due from the counterparties may be settled in cash or offset, in accordance with the agreements. Mortgage Loans on Real Estate Mortgage loans represented approximately 9.1% and 8.5% of the Company’s total investments as of December 31, 2018 and 2017 , respectively. As of December 31, 2018 , mortgage loans were geographically dispersed throughout the U.S. with the largest concentrations in California ( 18.7% ), Texas ( 10.9% ) and Washington ( 7.4% ) and include loans secured by properties in Canada ( 2.7% ) and United Kingdom ( 0.1% ). The recorded investment in mortgage loans on real estate presented below is gross of unamortized deferred loan origination fees and expenses, and valuation allowances. The distribution of mortgage loans by property type is as follows as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Carrying Value Percentage of Total Carrying Value Percentage of Total Property type: Office building $ 1,725,748 34.6 % $ 1,487,392 33.6 % Retail 1,432,394 28.7 1,270,676 28.8 Industrial 961,924 19.3 938,612 21.3 Apartment 571,291 11.5 510,052 11.6 Other commercial 291,997 5.9 206,439 4.7 Recorded investment $ 4,983,354 100.0 % $ 4,413,171 100.0 % Unamortized balance of loan origination fees and expenses (5,770 ) (3,254 ) Valuation allowances (11,286 ) (9,384 ) Total mortgage loans on real estate $ 4,966,298 $ 4,400,533 The maturities of the mortgage loans as of December 31, 2018 and 2017 are as follows (dollars in thousands): 2018 2017 Recorded Investment % of Total Recorded Investment % of Total Due within five years $ 1,425,598 28.6 % $ 1,091,066 24.8 % Due after five years through ten years 2,686,264 53.9 2,516,872 57.0 Due after ten years 871,492 17.5 805,233 18.2 Total $ 4,983,354 100.0 % $ 4,413,171 100.0 % The following tables set forth certain key credit quality indicators of the Company’s recorded investment in mortgage loans as of December 31, 2018 and 2017 (dollars in thousands): Recorded Investment Debt Service Ratios Construction loans >1.20x 1.00x - 1.20x <1.00x Total % of Total December 31, 2018: Loan-to-Value Ratio 0% - 59.99% $ 2,410,556 $ 61,246 $ 38,177 $ 13,691 $ 2,523,670 50.6 % 60% - 69.99% 1,618,374 73,908 38,120 18,929 1,749,331 35.1 70% - 79.99% 414,269 48,438 54,440 — 517,147 10.4 Greater than 80% 117,978 49,668 25,560 — 193,206 3.9 Total $ 4,561,177 $ 233,260 $ 156,297 $ 32,620 $ 4,983,354 100.0 % Recorded Investment Debt Service Ratios Construction loans >1.20x 1.00x - 1.20x <1.00x Total % of Total December 31, 2017: Loan-to-Value Ratio 0% - 59.99% $ 2,148,428 $ 53,979 $ 3,801 $ — $ 2,206,208 50.0 % 60% - 69.99% 1,517,029 47,128 43,921 — 1,608,078 36.4 70% - 79.99% 396,446 19,461 15,367 — 431,274 9.8 Greater than 80% 120,850 30,713 6,362 9,686 167,611 3.8 Total $ 4,182,753 $ 151,281 $ 69,451 $ 9,686 $ 4,413,171 100.0 % The age analysis of the Company’s past due recorded investments in mortgage loans as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 31-60 days past due $ — $ 17,100 61-90 days past due — 2,056 Total past due — 19,156 Current 4,983,354 4,394,015 Total $ 4,983,354 $ 4,413,171 The following table presents the recorded investment in mortgage loans, by method of measuring impairment, and the related valuation allowances, as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Mortgage loans: Individually measured for impairment $ 30,635 $ 5,858 Collectively measured for impairment 4,952,719 4,407,313 Recorded investment $ 4,983,354 $ 4,413,171 Valuation allowances: Individually measured for impairment $ — $ — Collectively measured for impairment 11,286 9,384 Total valuation allowances $ 11,286 $ 9,384 Information regarding the Company’s loan valuation allowances for mortgage loans as of December 31, 2018, 2017 and 2016 are as follows (dollars in thousands): 2018 2017 2016 Balance, beginning of period $ 9,384 $ 7,685 $ 6,813 Provision 1,918 1,691 872 Translation adjustment (16 ) 8 — Balance, end of period $ 11,286 $ 9,384 $ 7,685 Information regarding the portion of the Company’s mortgage loans that were impaired as of December 31, 2018 and 2017 is as follows (dollars in thousands): Unpaid Principal Balance Recorded Investment Related Allowance Carrying Value December 31, 2018: Impaired mortgage loans with no valuation allowance recorded $ 30,660 $ 30,635 $ — $ 30,635 Impaired mortgage loans with valuation allowance recorded — — — — Total impaired mortgage loans $ 30,660 $ 30,635 $ — $ 30,635 December 31, 2017: Impaired mortgage loans with no valuation allowance recorded $ 6,427 $ 5,858 $ — $ 5,858 Impaired mortgage loans with valuation allowance recorded — — — — Total impaired mortgage loans $ 6,427 $ 5,858 $ — $ 5,858 The Company’s average investment balance of impaired mortgage loans and the related interest income are reflected in the table below for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): 2018 2017 2016 Average Investment (1) Interest Income Average Investment (1) Interest Income Average Investment (1) Interest Income Impaired mortgage loans with no valuation allowance recorded $ 24,240 $ 1,129 $ 3,621 $ 186 $ 2,249 $ 142 Impaired mortgage loans with valuation allowance recorded — — — — — — Total $ 24,240 $ 1,129 $ 3,621 $ 186 $ 2,249 $ 142 (1) Average recorded investment represents the average loan balances as of the beginning of period and all subsequent quarterly end of period balances. The Company did not acquire any impaired mortgage loans during the years ended December 31, 2018 and 2017 . The Company had no mortgage loans that were on a nonaccrual status as of December 31, 2018 and 2017 . Policy Loans Policy loans comprised approximately 2.5% and 2.6% of the Company’s total investments as of December 31, 2018 and 2017 , respectively, the majority of which are associated with one client. These policy loans present no credit risk because the amount of the loan cannot exceed the obligation due to the ceding company upon the death of the insured or surrender of the underlying policy. The provisions of the treaties in force and the underlying policies determine the policy loan interest rates. The Company earns a spread between the interest rate earned on policy loans and the interest rate credited to corresponding liabilities. Funds Withheld at Interest Funds withheld at interest comprised approximately 10.6% and 11.8% of the Company’s total investments as of December 31, 2018 and 2017 , respectively. Of the $5.8 billion funds withheld at interest balance, net of embedded derivatives, as of December 31, 2018 , $3.8 billion of the balance is associated with one client. For reinsurance agreements written on a modco basis and certain agreements written on a coinsurance funds withheld basis, assets equal to the net statutory reserves are withheld and legally owned and managed by the ceding company and are reflected as funds withheld at interest on the Company’s consolidated balance sheets. In the event of a ceding company’s insolvency, the Company would need to assert a claim on the assets supporting its reserve liabilities. However, the risk of loss to the Company is mitigated by its ability to offset amounts it owes the ceding company for claims or allowances against amounts owed to the Company from the ceding company. Other Invested Assets Other invested assets include limited partnership interests, joint ventures (other than operating joint ventures), equity release mortgages, derivative contracts and fair value option (“FVO”) contractholder-directed unit-linked investments. Other invested assets also include Federal Home Loan Bank of Des Moines (“FHLB”) common stock, which is included in Other in the table below. Other invested assets represented approximately 3.5% and 2.9% of the Company’s total investments as of December 31, 2018 and 2017 , respectively. Carrying values of these assets as of December 31, 2018 and 2017 are as follows (dollars in thousands): 2018 2017 Limited partnership interests and real estate joint ventures $ 965,094 $ 781,124 Equity release mortgages 475,905 219,940 Derivatives 180,699 137,613 FVO contractholder-directed unit-linked investments 197,770 218,541 Other 95,829 148,114 Total other invested assets $ 1,915,297 $ 1,505,332

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS Accounting for Derivative Instruments and Hedging Activities See Note 2 – “Significant Accounting Policies and Pronouncements” for a detailed discussion of the accounting treatment for derivative instruments, including embedded derivatives and Note 6 – “Fair Value of Assets and Liabilities” for additional disclosures related to the fair value hierarchy for derivative instruments, including embedded derivatives. Types of Derivatives Used by the Company Credit Derivatives The Company sells protection under single name credit default swaps and credit default swap index tranches to diversify its credit risk exposure in certain portfolios and, in combination with purchasing securities, to replicate characteristics of similar investments based on the credit quality and term of the credit default swap. Credit default triggers for indexed reference entities and single name reference entities are defined in the contracts. The Company’s maximum exposure to credit loss equals the notional value for credit default swaps. In the event of default of a referencing entity, the Company is typically required to pay the protection holder the full notional value less a recovery amount determined at auction. The Company also purchases credit default swaps to reduce its risk against a drop in bond prices due to credit concerns of certain bond issuers. If a credit event, as defined by the contract, occurs, the Company is able to put the bond back to the counterparty at par. Equity Derivatives Exchange-traded equity futures are used primarily to economically hedge liabilities embedded in certain variable annuity products. With exchange-traded equity futures transactions, the Company agrees to purchase or sell a specified number of contracts, the value of which is determined by the relevant stock indices, and to post variation margin on a daily basis in an amount equal to the difference between the daily estimated fair values of those contracts. The Company enters into exchange-traded equity futures with regulated futures commission merchants that are members of the exchange. Equity index options are used by the Company primarily to hedge minimum guarantees embedded in certain variable annuity products. To hedge against adverse changes in equity indices volatility, the Company buys put options. The contracts are net settled in cash based on differentials in the indices at the time of exercise and the strike price. Equity warrants have also been used by the Company to economically hedge the variability in anticipated cash flows for the acquisition of investment securities. Foreign Currency Derivatives Foreign currency swaps are used by the Company to reduce the risk from fluctuations in foreign currency exchange rates associated with its assets and liabilities denominated in foreign currencies. With a foreign currency swap transaction, the Company agrees with another party to exchange, at specified intervals, the difference between one currency and another at a forward exchange rate calculated by reference to an agreed upon principal amount. The principal amount of each currency is exchanged at the termination of the currency swap by each party. The Company uses foreign currency swaps in hedges of net investments in foreign operations and fair value hedges. Foreign currency forwards are used by the Company to reduce the risk from fluctuations in foreign currency exchange rates associated with its assets and liabilities denominated in foreign currencies. With a foreign currency forward transaction, the Company agrees with another party to deliver a specified amount of an identified currency at a specified future date. The price is agreed upon at the time of the contract and payment for such a contract is made in a different currency at the specified future date. The Company uses foreign currency forwards in hedges of net investments in foreign operations and non-qualifying hedge relationships. Interest Rate Derivatives Interest rate swaps are used by the Company primarily to reduce market risks from changes in interest rates, to alter interest rate exposure arising from mismatches between assets and liabilities (duration mismatches) and to manage the risk of cash flows of liabilities that are variable based on a benchmark rate. With an interest rate swap, the Company agrees with another party to exchange, at specified intervals, the difference between two rates, which can be either fixed-rate or floating-rate interest amounts, tied to an agreed-upon notional principal amount. These transactions are executed pursuant to master agreements that provide for a single net payment or individual gross payments at each due date. The Company utilizes interest rate swaps in cash flow and non-qualifying hedging relationships. The Company sells fee-based synthetic guaranteed investment contracts (“GICs”) to retirement plans that include investment-only, stable value contracts. The assets are owned by the trustees of such plans, who invest the assets under the terms of investment guidelines to which the Company agrees. The contracts contain a guarantee of a minimum rate of return on participant balances supported by the underlying assets, and a guarantee of liquidity to meet certain participant-initiated plan cash flow requirements. These contracts are reported as derivatives and recorded at fair value. Other Derivatives Consumer price index (“CPI”) swaps are used by the Company primarily to economically hedge liabilities embedded in certain insurance products where value is directly affected by changes in a designated benchmark consumer price index. With a CPI swap transaction, the Company agrees with another party to exchange the actual amount of inflation realized over a specified period of time for a fixed amount of inflation determined at inception. These transactions are executed pursuant to master agreements that provide for a single net payment or individual gross payments to be made by the counterparty at each due date. Most of these swaps will require a single payment to be made by one counterparty at the maturity date of the swap. The Company enters into longevity swaps in the form of out-of-the-money options, which provide protection against changes in mortality improvement to retirement plans and insurers of such plans. With a longevity swap transaction, the Company agrees with another party to exchange a proportion of a notional value. The proportion is determined by the difference between a predefined benefit, and the realized benefit plus the future expected benefit, calculated by reference to a population index for a fixed premium. Mortality swaps are used by the Company to hedge risk from changes in mortality experience associated with its reinsurance of life insurance risk. The Company agrees with another party to exchange, at specified intervals, a proportion of a notional value determined by the difference between a predefined expected and realized claim amount on a designated index of reinsured lives, for a fixed percentage (premium) each term. The Company has certain embedded derivatives that are required to be separated from their host contracts and reported as derivatives. Host contracts include reinsurance treaties structured on a modco or funds withheld basis. Additionally, the Company reinsures equity-indexed annuity and variable annuity contracts with benefits that are considered embedded derivatives, including guaranteed minimum withdrawal benefits, guaranteed minimum accumulation benefits, and guaranteed minimum income benefits. The changes in fair values of embedded derivatives on equity-indexed annuities described below relate to changes in the fair value associated with capital market and other related assumptions. The Company’s utilization of a credit valuation adjustment did not have a material effect on the change in fair value of its embedded derivatives for the years ended December 31, 2018, 2017 and 2016 . Summary of Derivative Positions Derivatives, except for embedded derivatives and longevity and mortality swaps, are carried on the Company’s consolidated balance sheets in other invested assets or other liabilities, at fair value. Longevity and mortality swaps are included on the consolidated balance sheets in other assets or other liabilities, at fair value. Embedded derivative assets and liabilities on modco or funds withheld arrangements are included on the consolidated balance sheets with the host contract in funds withheld at interest, at fair value. Embedded derivative liabilities on indexed annuity and variable annuity products are included on the consolidated balance sheets with the host contract in interest-sensitive contract liabilities, at fair value. The following table presents the notional amounts and gross fair value of derivative instruments prior to taking into account the netting effects of master netting agreements as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018 December 31, 2017 Primary Underlying Risk Notional Carrying Value/Fair Value Notional Carrying Value/Fair Value Amount Assets Liabilities Amount Assets Liabilities Derivatives not designated as hedging instruments: Interest rate swaps Interest rate $ 1,040,588 $ 47,652 $ 961 $ 996,204 $ 59,809 $ 2,372 Financial futures Equity 325,620 — — 412,438 — — Foreign currency swaps Foreign currency 149,698 504 4,659 — — — Foreign currency forwards Foreign currency 25,000 — 234 6,030 — 28 CPI swaps CPI 385,580 — 11,384 221,932 — 2,160 Credit default swaps Credit 1,338,300 6,003 1,166 961,200 8,319 1,651 Equity options Equity 439,158 42,836 — 632,251 23,271 — Longevity swaps Longevity 917,360 47,789 — 960,400 40,659 — Mortality swaps Mortality 25,000 — 369 — — 1,683 Synthetic GICs Interest rate 13,397,729 — — 10,052,576 — — Embedded derivatives in: Modco or funds withheld arrangements — 109,597 — — 122,194 — Indexed annuity products — — 776,940 — — 861,758 Variable annuity products — — 167,925 — — 152,470 Total non-hedging derivatives 18,044,033 254,381 963,638 14,243,031 254,252 1,022,122 Derivatives designated as hedging instruments: Interest rate swaps Foreign currency/Interest rate 435,000 — 27,257 435,000 — 20,389 Foreign currency swaps Foreign currency 494,461 51,311 — 672,921 65,207 8,496 Foreign currency forwards Foreign currency 911,197 50,974 — 553,175 1,265 7,720 Total hedging derivatives 1,840,658 102,285 27,257 1,661,096 66,472 36,605 Total derivatives $ 19,884,691 $ 356,666 $ 990,895 $ 15,904,127 $ 320,724 $ 1,058,727 Fair Value Hedges The Company designates and reports certain foreign currency swaps to hedge the foreign currency fair value exposure of foreign currency denominated assets as fair value hedges when they meet the requirements of the general accounting principles for Derivatives and Hedging. The gain or loss on the hedged item attributable to a change in foreign currency and the offsetting gain or loss on the related foreign currency swaps as of December 31, 2018, 2017 and 2016 were (dollars in thousands): Type of Fair Value Hedge Hedged Item Gains (Losses) Recognized for Derivatives (1) Gains (Losses) Recognized for Hedged Items (1) For the Year Ended December 31, 2018: Foreign currency swaps Foreign-denominated fixed maturity securities $ (11,164 ) $ 12,446 For the Year Ended December 31, 2017: Foreign currency swaps Foreign-denominated fixed maturity securities $ 9,456 $ (9,456 ) For the Year Ended December 31, 2016: Foreign currency swaps Foreign-denominated fixed maturity securities $ (1,700 ) $ 1,700 (1) The net amount represents the ineffective portion of the fair value hedges. Cash Flow Hedges Certain derivative instruments are designated as cash flow hedges when they meet the requirements of the general accounting principles for Derivatives and Hedging . The Company designates and accounts for the following as cash flows: (i) certain interest rate swaps, in which the cash flows of liabilities are variable based on a benchmark rate; (ii) certain interest rate swaps, in which the cash flows of assets are denominated in different currencies, commonly referred to as cross-currency swaps; and (iii) forward bond purchase commitments. The following table presents the components of AOCI, before income tax, and the consolidated income statement classification where the gain or loss is recognized related to cash flow hedges for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): Amounts Included in AOCI Balance December 31, 2015 $ (29,397 ) Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges 27,110 Amounts reclassified to investment related (gains) losses, net 278 Amounts reclassified to investment income (487 ) Balance December 31, 2016 (2,496 ) Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges 6,316 Amounts reclassified to investment related (gains) losses, net (775 ) Amounts reclassified to investment income (505 ) Amounts reclassified to interest expense 79 Balance December 31, 2017 2,619 Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges 6,644 Amounts reclassified to investment income (292 ) Amounts reclassified to interest expense (183 ) Balance December 31, 2018 $ 8,788 As of December 31, 2018 , the before-tax deferred net gains on derivative instruments recorded in AOCI that are expected to be reclassified to earnings during the next twelve months are approximately $0.1 million and $1.9 million in investment income and interest expense, respectively. The following table presents the effective portion of derivatives in cash flow hedging relationships on the consolidated statements of income and the consolidated statements of stockholders’ equity for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): Effective Portion Derivative Type Gains (Losses) Deferred in OCI Gains (Losses) Reclassified into Income from OCI For the year ended December 31, 2018: Investment Related Gains (Losses) Investment Income Interest Expense Interest rate $ 12,886 $ — $ — $ 183 Foreign currency/Interest rate (6,242 ) — 292 — Total $ 6,644 $ — $ 292 $ 183 For the year ended December 31, 2017: Interest rate $ (5,649 ) $ — $ — $ (79 ) Foreign currency/Interest rate 11,955 — 380 — Forward bond purchase commitments 10 775 125 — Total $ 6,316 $ 775 $ 505 $ (79 ) For the year ended December 31, 2016: Interest rate $ 27,901 $ — $ — $ — Foreign currency/Interest rate (791 ) — 510 — Forward bond purchase commitments — (278 ) (23 ) — Total $ 27,110 $ (278 ) $ 487 $ — For the years ended December 31, 2018, 2017 and 2016 , the ineffective portion of derivatives reported as cash flow hedges was not material to the Company’s results of operations. Also, there were no material amounts reclassified into earnings relating to instances in which the Company discontinued cash flow hedge accounting because the forecasted transaction did not occur by the anticipated date or within the additional time period permitted by the authoritative guidance for the accounting for derivatives and hedging. Hedges of Net Investments in Foreign Operations The Company uses foreign currency swaps and foreign currency forwards to hedge a portion of its net investment in certain foreign operations against adverse movements in exchange rates. The following table illustrates the Company’s net investments in foreign operations (“NIFO”) hedges for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): Derivative Gains (Losses) Deferred in AOCI For the year ended Type of NIFO Hedge (1) (2) 2018 2017 2016 Foreign currency swaps $ 31,431 $ (37,567 ) $ (10,234 ) Foreign currency forwards 55,913 (10,386 ) — (1) There were no sales or substantial liquidations of net investments in foreign operations that would have required the reclassification of gains or losses from accumulated other comprehensive income (loss) into investment income during the periods presented. (2) There was no ineffectiveness recognized for the Company’s hedges of net investments in foreign operations. The cumulative foreign currency translation gain recorded in AOCI related to these hedges was $201.0 million and $113.7 million as of December 31, 2018 and 2017 , respectively. If a hedged foreign operation was sold or substantially liquidated, the amounts in AOCI would be reclassified to the consolidated statements of income. A pro rata portion would be reclassified upon partial sale of a hedged foreign operation. Non-qualifying Derivatives and Derivatives for Purposes Other Than Hedging The Company uses various other derivative instruments for risk management purposes that either do not qualify or have not been qualified for hedge accounting treatment. The gain or loss related to the change in fair value for these derivative instruments is recognized in investment related gains (losses), net in the consolidated statements of income, except where otherwise noted. A summary of the effect of non-hedging derivatives, including embedded derivatives, on the Company’s consolidated statements of income for the years ended December 31, 2018, 2017 and 2016 is as follows (dollars in thousands): Gains (Losses) for the Years Ended December 31, Type of Non-hedging Derivative Income Statement Location of Gains (Losses) 2018 2017 2016 Interest rate swaps Investment related gains (losses), net $ (21,314 ) $ 11,278 $ 7,649 Financial futures Investment related gains (losses), net 21,200 (36,160 ) (40,242 ) Foreign currency swaps Investment related gains (losses), net (3,695 ) — — Foreign currency forwards Investment related gains (losses), net (234 ) 591 1,630 Consumer price index swaps Investment related gains (losses), net (10,047 ) (2,078 ) (401 ) Credit default swaps Investment related gains (losses), net (2,150 ) 18,118 18,100 Equity options Investment related gains (losses), net 7,315 (42,953 ) (28,270 ) Longevity swaps Other revenues 9,215 9,358 13,095 Mortality swaps Other revenues (386 ) (921 ) (172 ) Subtotal (96 ) (42,767 ) (28,611 ) Embedded derivatives in: Modco or funds withheld arrangements Investment related gains (losses), net (12,597 ) 144,723 54,169 Indexed annuity products Interest credited 27,591 (80,062 ) 10,708 Variable annuity products Investment related gains (losses), net (15,455 ) 32,166 7,835 Total non-hedging derivatives $ (557 ) $ 54,060 $ 44,101 Credit Derivatives The following table presents the estimated fair value, maximum amount of future payments and weighted average years to maturity of credit default swaps sold by the Company as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Rating Agency Designation of Referenced Credit Obligations (1) Estimated Fair Value of Credit Default Swaps Maximum Amount of Future Payments under Credit Default Swaps (2) Weighted Average Years to Maturity (3) Estimated Fair Maximum (2) Weighted (3) AAA/AA+/AA/AA-/A+/A/A- Single name credit default swaps $ 1,953 $ 152,000 2.2 $ 3,128 $ 162,000 2.9 Subtotal 1,953 152,000 2.2 3,128 162,000 2.9 BBB+/BBB/BBB- Single name credit default swaps 2,930 353,700 2.2 4,469 361,700 2.9 Credit default swaps referencing indices (76 ) 817,600 6.4 (55 ) 422,600 4.0 Subtotal 2,854 1,171,300 5.1 4,414 784,300 3.5 BB+/BB/BB- Single name credit default swaps 30 15,000 0.7 30 5,000 1.5 Subtotal 30 15,000 0.7 30 5,000 1.5 Total $ 4,837 $ 1,338,300 4.7 $ 7,572 $ 951,300 3.4 (1) The rating agency designations are based on ratings from Standard and Poor’s (“S&P”). (2) Assumes the value of the referenced credit obligations is zero. (3) The weighted average years to maturity of the credit default swaps is calculated based on weighted average notional amounts. Netting Arrangements and Credit Risk Certain of the Company’s derivatives are subject to enforceable master netting arrangements and reported as a net asset or liability in the consolidated balance sheets. The Company nets all derivatives that are subject to such arrangements. The Company has elected to include all derivatives, except embedded derivatives, in the tables below, irrespective of whether they are subject to an enforceable master netting arrangement or a similar agreement. See Note 4 – “Investments” for information regarding the Company’s securities borrowing, lending, repurchase and repurchase/reverse repurchase programs. See “Embedded Derivatives” above for information regarding the Company’s bifurcated embedded derivatives. The following table provides information relating to the netting of the Company’s derivative instruments as of December 31, 2018 and December 31, 2017 (dollars in thousands): Gross Amounts Not Offset in the Balance Sheet Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts Presented in the Balance Sheet Financial Instruments (1) Cash Collateral Pledged/ Received Net Amount December 31, 2018: Derivative assets $ 247,069 $ (18,581 ) $ 228,488 $ — $ (235,611 ) $ (7,123 ) Derivative liabilities 46,030 (18,581 ) 27,449 (71,376 ) (24,080 ) (68,007 ) December 31, 2017: Derivative assets $ 198,530 $ (20,258 ) $ 178,272 $ (862 ) $ (185,900 ) $ (8,490 ) Derivative liabilities 44,499 (20,258 ) 24,241 (58,156 ) (22,221 ) (56,136 ) (1) Includes initial margin posted to a central clearing partner. The Company may be exposed to credit-related losses in the event of non-performance by counterparties to derivative financial instruments with a positive fair value. Generally, the credit exposure of the Company’s derivative contracts is limited to the fair value at the reporting date plus or minus any collateral posted or held by the Company. The Company had no credit exposure related to its derivative contracts, as of December 31, 2018 and 2017 , as the net amount of collateral pledged to the Company from counterparties exceeded the fair value of the derivative contracts. Derivatives may be exchange-traded or they may be privately negotiated contracts, which are referred to as over-the-counter (“OTC”) derivatives. Certain of the Company’s OTC derivatives are cleared and settled through central clearing counterparties (“OTC cleared”) and others are bilateral contracts between two counterparties. The Company manages its credit risk related to OTC derivatives by entering into transactions with creditworthy counterparties, maintaining collateral arrangements and through the use of master netting agreements that provide for a single net payment to be made by one counterparty to another at each due date and upon termination. The Company is only exposed to the default of the central clearing counterparties for OTC cleared derivatives, and these transactions require initial and daily variation margin collateral postings. Exchange-traded derivatives are settled on a daily basis, thereby reducing the credit risk exposure in the event of non-performance by counterparties to such financial instruments.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	FAIR VALUE OF ASSETS AND LIABILITIES Fair Value Measurement General accounting principles for Fair Value Measurements and Disclosures define fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. These principles also establish a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value and describes three levels of inputs that may be used to measure fair value: Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities. Active markets are defined as having the following characteristics for the measured asset/liability: (i) many transactions, (ii) current prices, (iii) price quotes not varying substantially among market makers, (iv) narrow bid/ask spreads and (v) most information publicly available. The Company’s Level 1 assets and liabilities are traded in active exchange markets. Level 2 - Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or market standard valuation techniques and assumptions that use significant inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Such observable inputs include benchmarking prices for similar assets in active, liquid markets, quoted prices in markets that are not active and observable yields and spreads in the market. The Company’s Level 2 assets and liabilities include investment securities with quoted prices that are traded less frequently than exchange-traded instruments and derivative contracts whose values are determined using market standard valuation techniques. Level 2 valuations are generally obtained from third party pricing services for identical or comparable assets or liabilities or through the use of valuation methodologies using observable market inputs. Prices from servicers are validated through analytical reviews and assessment of current market activity. Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the related assets or liabilities. Level 3 assets and liabilities include those whose value is determined using market standard valuation techniques described above. When observable inputs are not available, the market standard techniques for determining the estimated fair value of certain securities that trade infrequently, and therefore have little transparency, rely on inputs that are significant to the estimated fair value and that are not observable in the market or cannot be derived principally from or corroborated by observable market data. These unobservable inputs can be based in large part on management judgment or estimation and cannot be supported by reference to market activity. Even though unobservable, management believes these inputs are based on assumptions deemed appropriate given the circumstances and consistent with what other market participants would use when pricing similar assets and liabilities. Prices are determined using valuation methodologies such as discounted cash flow models and other similar techniques that require management’s judgment or estimation in developing inputs that are consistent with those other market participants would use when pricing similar assets and liabilities. Non-binding broker quotes, which are utilized when pricing service information is not available, are reviewed for reasonableness based on the Company’s understanding of the market, and are generally considered Level 3. Under certain circumstances, based on its observations of transactions in active markets, the Company may conclude the prices received from independent third party pricing services or brokers are not reasonable or reflective of market activity. In those instances, the Company would apply internally developed valuation techniques to the related assets or liabilities. Additionally, the Company’s embedded derivatives, all of which are associated with reinsurance treaties, and longevity and mortality swaps are classified in Level 3 since their values include significant unobservable inputs. When inputs used to measure the fair value of an asset or liability fall within different levels of the hierarchy, the level within which the fair value measurement is categorized is based on the lowest level input that is significant to the fair value measurement in its entirety, except for fair value measurements using NAV. For example, a Level 3 fair value measurement may include inputs that are observable (Levels 1 and 2) and unobservable (Level 3). Therefore, gains and losses for such assets and liabilities categorized within Level 3 may include changes in fair value that are attributable to both observable inputs (Levels 1 and 2) and unobservable inputs (Level 3). Assets and Liabilities by Hierarchy Level Assets and liabilities measured at fair value on a recurring basis as of December 31, 2018 and 2017 are summarized below (dollars in thousands): December 31, 2018: Fair Value Measurements Using: Total Level 1 Level 2 Level 3 Assets: Fixed maturity securities – available-for-sale: Corporate $ 23,982,119 $ — $ 22,651,194 $ 1,330,925 Canadian government 3,892,385 — 3,364,261 528,124 RMBS 1,869,221 — 1,862,366 6,855 ABS 2,149,204 — 2,053,632 95,572 CMBS 1,419,034 — 1,419,012 22 U.S. government 2,185,874 2,067,529 100,320 18,025 State and political subdivisions 752,194 — 741,992 10,202 Other foreign government 3,742,315 — 3,737,309 5,006 Total fixed maturity securities – available-for-sale 39,992,346 2,067,529 35,930,086 1,994,731 Equity securities 82,197 48,737 — 33,460 Funds withheld at interest – embedded derivatives 109,597 — — 109,597 Cash equivalents 485,167 473,509 11,658 — Short-term investments 105,991 4,989 98,774 2,228 Other invested assets: Derivatives: Interest rate swaps 37,976 — 37,976 — Foreign currency forwards 50,740 — 50,740 — Credit default swaps 4,466 — 4,466 — Equity options 36,206 — 36,206 — Foreign currency swaps 51,311 — 51,311 — FVO contractholder-directed unit-linked investments 197,770 196,781 989 — Total other invested assets 378,469 196,781 181,688 — Other assets - longevity swaps 47,789 — — 47,789 Total $ 41,201,556 $ 2,791,545 $ 36,222,206 $ 2,187,805 Liabilities: Interest-sensitive contract liabilities – embedded derivatives $ 944,865 $ — $ — $ 944,865 Other liabilities: Derivatives: Interest rate swaps 18,542 — 18,542 — Foreign currency swaps - non-hedged 4,155 — 4,155 — CPI swaps 11,384 — 11,384 — Credit default swaps (371 ) — (371 ) — Equity options (6,630 ) — (6,630 ) — Mortality swaps 369 — — 369 Total $ 972,314 $ — $ 27,080 $ 945,234 December 31, 2017: Fair Value Measurements Using: Total Level 1 Level 2 Level 3 Assets: Fixed maturity securities – available-for-sale: Corporate $ 23,210,968 $ — $ 21,873,696 $ 1,337,272 Canadian government 4,220,076 — 3,626,134 593,942 RMBS 1,719,880 — 1,611,998 107,882 ABS 1,648,362 — 1,524,888 123,474 CMBS 1,303,387 — 1,300,153 3,234 U.S. government 1,943,592 1,818,006 103,075 22,511 State and political subdivisions 703,428 — 662,225 41,203 Other foreign government 3,401,127 — 3,396,035 5,092 Total fixed maturity securities – available-for-sale 38,150,820 1,818,006 34,098,204 2,234,610 Equity securities: Non-redeemable preferred stock 39,806 39,806 — — Other equity securities 60,346 60,346 — — Funds withheld at interest – embedded derivatives 122,194 — — 122,194 Cash equivalents 356,788 354,071 2,717 — Short-term investments 50,746 — 47,650 3,096 Other invested assets: Derivatives: Interest rate swaps 51,359 — 51,359 — Foreign currency forwards 730 — 730 — CPI swaps (221 ) — (221 ) — Credit default swaps 5,908 — 5,908 — Equity options 16,932 — 16,932 — Foreign currency swaps 62,905 — 62,905 — FVO contractholder-directed unit-linked investments 218,541 217,618 923 — Total other invested assets 356,154 217,618 138,536 — Other assets - longevity swaps 40,659 — — 40,659 Total $ 39,177,513 $ 2,489,847 $ 34,287,107 $ 2,400,559 Liabilities: Interest-sensitive contract liabilities – embedded derivatives $ 1,014,228 $ — $ — $ 1,014,228 Other liabilities: Derivatives: Interest rate swaps 14,311 — 14,311 — Foreign currency forwards 7,213 — 7,213 — CPI swaps 1,939 — 1,939 — Credit default swaps (760 ) — (760 ) — Equity options (6,339 ) — (6,339 ) — Foreign currency swaps 6,194 — 6,194 — Mortality swaps 1,683 — — 1,683 Total $ 1,038,469 $ — $ 22,558 $ 1,015,911 The Company may utilize information from third parties, such as pricing services and brokers, to assist in determining the fair value for certain assets and liabilities; however, management is ultimately responsible for all fair values presented in the Company’s financial statements. This includes responsibility for monitoring the fair value process, ensuring objective and reliable valuation practices and pricing of assets and liabilities, and approving changes to valuation methodologies and pricing sources. The selection of the valuation technique(s) to apply considers the definition of an exit price and the nature of the asset or liability being valued and significant expertise and judgment is required. The Company performs initial and ongoing analysis and review of the various techniques utilized in determining fair value to ensure that they are appropriate and consistently applied, and that the various assumptions are reasonable. The Company analyzes and reviews the information and prices received from third parties to ensure that the prices represent a reasonable estimate of the fair value and to monitor controls around pricing, which includes quantitative and qualitative analysis and is overseen by the Company’s investment and accounting personnel. Examples of procedures performed include, but are not limited to, review of pricing trends, comparison of a sample of executed prices of securities sold to the fair value estimates, comparison of fair value estimates to management’s knowledge of the current market, and ongoing confirmation that third party pricing services use, wherever possible, market-based parameters for valuation. In addition, the Company utilizes both internal and external cash flow models to analyze the reasonableness of fair values utilizing credit spread and other market assumptions, where appropriate. As a result of the analysis, if the Company determines there is a more appropriate fair value based upon the available market data, the price received from the third party is adjusted accordingly. The Company also determines if the inputs used in estimated fair values received from pricing services are observable by assessing whether these inputs can be corroborated by observable market data. For assets and liabilities reported at fair value, the Company utilizes when available, fair values based on quoted prices in active markets that are regularly and readily obtainable. Generally, these are very liquid investments and the valuation does not require management judgment. When quoted prices in active markets are not available, fair value is based on market valuation techniques, market comparable pricing and the income approach. The use of different techniques, assumptions and inputs may have a material effect on the estimated fair values of the Company’s securities holdings. For the periods presented, the application of market standard valuation techniques applied to similar assets and liabilities has been consistent. The methods and assumptions the Company uses to estimate the fair value of assets and liabilities measured at fair value on a recurring basis are summarized below. See “Valuation Process for Fair Value Measurements Categorized within Level 3” for additional information on Level 3 valuations. Fixed Maturity Securities – The fair values of the Company’s publicly-traded fixed maturity securities are generally based on prices obtained from independent pricing services. Prices from pricing services are sourced from multiple vendors, and a vendor hierarchy is maintained by asset type based on historical pricing experience and vendor expertise. The Company generally receives prices from multiple pricing services for each security, but ultimately uses the price from the vendor that is highest in the hierarchy for the respective asset type. To validate reasonableness, prices are periodically reviewed as explained above. Consistent with the fair value hierarchy described above, securities with quotes from pricing services are generally reflected within Level 2, as they are primarily based on observable pricing for similar assets and/or other market observable inputs. If the pricing information received from third party pricing services is not reflective of market activity or other inputs observable in the market, the Company may challenge the price through a formal process with the pricing service. If the Company ultimately concludes that pricing information received from the independent pricing service is not reflective of fair value, non-binding broker quotes are used, if available. If the Company concludes that the values from both pricing services and brokers are not reflective of fair value, an internally developed valuation may be prepared; however, this occurs infrequently. Internally developed valuations or non-binding broker quotes are also used to determine fair value in circumstances where vendor pricing is not available. These valuations may use significant unobservable inputs, which reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset. Observable market data may not be available in certain circumstances such as market illiquidity and credit events related to the security. Pricing service overrides, internally developed valuations and non-binding broker quotes are generally based on significant unobservable inputs and are reflected as Level 3 in the valuation hierarchy. The inputs used in the valuation of corporate and government securities include, but are not limited to standard market observable inputs that are derived from, or corroborated by, market observable data including market yield curve, duration, call provisions, observable prices and spreads for similar publicly traded or privately placed issues that incorporate the credit quality and industry sector of the issuer. For private placements and structured securities, valuation is based primarily on matrix pricing or other similar techniques using standard market inputs including spreads for actively traded securities, spreads off benchmark yields, expected prepayment speeds and volumes, current and forecasted loss severity, rating, weighted average coupon, weighted average maturity, average delinquency rates, geographic region, debt service coverage ratios and issuance-specific information including, but not limited to: collateral type, payment terms of the underlying assets, payment priority within the tranche, structure of the security, deal performance and vintage of loans. When observable inputs are not available, the market standard valuation techniques for determining the estimated fair value of certain types of securities that trade infrequently, and therefore have little or no price transparency, rely on inputs that are significant to the estimated fair value that are not observable in the market or cannot be derived principally from or corroborated by observable market data, such as market illiquidity. Other significant unobservable inputs used in the fair value measurement of the Company’s private debt investments include a multiple of earnings before interest, taxes, depreciation and amortization (“EBITDA”). These unobservable inputs can be based in large part on management judgment or estimation, and cannot be supported by reference to market activity. Even though unobservable, these inputs are based on assumptions deemed appropriate given the circumstances and are believed to be consistent with what other market participants would use when pricing such securities. Embedded Derivatives – The fair value of embedded derivative liabilities, including those calculated by third parties, are monitored through the use of attribution reports to quantify the effect of underlying sources of fair value change, including capital market inputs based on policyholder account values, interest rates and short-term and long-term implied volatilities, from period to period. Actuarial assumptions are based on experience studies performed internally in combination with available industry information and are reviewed on a periodic basis, at least annually. For embedded derivative liabilities associated with the underlying products in reinsurance treaties, primarily equity-indexed and variable annuity treaties, the Company utilizes a discounted cash flow model, which includes an estimate of future equity option purchases and an adjustment for a CVA. The variable annuity embedded derivative calculations are performed by third parties based on methodology and input assumptions provided by the Company. To validate the reasonableness of the resulting fair value, the Company’s internal actuaries perform reviews and analytical procedures on the results. The capital market inputs to the model, such as equity indexes, short-term equity volatility and interest rates, are generally observable. The valuation also requires certain significant inputs, which are generally not observable and accordingly, the valuation is considered Level 3 in the fair value hierarchy, The fair value of embedded derivatives associated with funds withheld reinsurance treaties is determined based upon a total return swap technique with reference to the fair value of the investments held by the ceding company that support the Company’s funds withheld at interest asset with an adjustment for a CVA. The fair value of the underlying assets is generally based on market observable inputs using industry standard valuation techniques. The valuation also requires certain significant inputs, which are generally not observable and accordingly, the valuation is considered Level 3 in the fair value hierarchy. Equity Securities – Equity securities consist principally of exchange-traded funds and common and preferred stock of publicly and privately traded companies. The fair values of publicly traded equity securities are primarily based on quoted market prices in active markets and are classified within Level 1 in the fair value hierarchy. Non-binding broker quotes and internally developed evaluations for equity securities are generally based on significant unobservable inputs and are reflected as Level 3 in the fair value hierarchy. Credit Valuation Adjustment – The Company uses a structural default risk model to estimate a CVA. The input assumptions are a combination of externally derived and published values (default threshold and uncertainty), market inputs (interest rate, equity price per share, debt per share, equity price volatility) and insurance industry data (Loss Given Default), adjusted for market recoverability. Cash Equivalents and Short-Term Investments – Cash equivalents and short-term investments include money market instruments, commercial paper and other highly liquid debt instruments. Money market instruments are generally valued using unadjusted quoted prices in active markets that are accessible for identical assets and are primarily classified as Level 1. The fair value of certain other cash equivalents and short-term investments, such as bonds with original maturities twelve months or less, are based upon other market observable data and are typically classified as Level 2. However, certain short-term investments may incorporate significant unobservable inputs resulting in a Level 3 classification. Various time deposits, certificates of deposit and sweeps carried as cash equivalents or short-term investments are not measured at estimated fair value and therefore are excluded from the tables presented. FVO Contractholder-Directed Unit-Linked Investments – FVO contractholder-directed investments supporting unit-linked variable annuity type liabilities primarily consist of exchange-traded funds and, to a lesser extent, fixed maturity securities and cash and cash equivalents. The fair values of the exchange-traded securities are primarily based on quoted market prices in active markets and are classified within Level 1 of the hierarchy. The fair value of the fixed maturity contractholder-directed securities is determined on a basis consistent with the methodologies described above for fixed maturity securities and are classified within Level 2 of the hierarchy. Derivative Assets and Derivative Liabilities – All of the derivative instruments utilized by the Company, except for longevity and mortality swaps, are classified within Level 2 on the fair value hierarchy. These derivatives are principally valued using an income approach. Valuations of interest rate contracts are based on present value techniques, which utilize significant inputs that may include the swap yield curve, London Interbank Offered Rate (“LIBOR”) basis curves, and repurchase rates. Valuations of foreign currency contracts are based on present value techniques, which utilize significant inputs that may include the swap yield curve, LIBOR basis curves, currency spot rates, and cross currency basis curves. Valuations of credit contracts, are based on present value techniques, which utilize significant inputs that may include the swap yield curve, credit curves, and recovery rates. Valuations of equity market contracts, are based on present value techniques, which utilize significant inputs that may include the swap yield curve, spot equity index levels, and dividend yield curves. Valuations of equity market contracts, option-based, are based on option pricing models, which utilize significant inputs that may include the swap yield curve, spot equity index levels, dividend yield curves, and equity volatility. Longevity and Mortality Swaps – The Company utilizes a discounted cash flow model to estimate the fair value of longevity and mortality swaps. The fair value of these swaps includes an accrual for premiums payable and receivable. Some inputs to the valuation model are generally observable, such as interest rates and actual population mortality experience. The valuation also requires significant inputs that are generally not observable and, accordingly, the valuation is considered Level 3 in the fair value hierarchy. Transfers between Levels 1 and 2 Transfers between Levels 1 and 2 are made to reflect changes in observability of inputs and market activity. The Company recognizes transfers of assets and liabilities into and out of levels within the fair value hierarchy at the beginning of the quarter in which the actual event or change in circumstances that caused the transfer occurs. There were no transfers between Level 1 and Level 2 for the year ended December 31, 2018. The following table presents the transfers between Level 1 and Level 2 during the year ended December 31, 2017 (dollars in thousands): 2017 Transfers from Level 1 to Level 2 Transfers from Level 2 to Level 1 Fixed maturity securities - available-for-sale: Corporate $ 596,809 $ 88,674 Other foreign government 317,640 — Quantitative Information Regarding Internally-Priced Assets and Liabilities The following table presents quantitative information about significant unobservable inputs used in Level 3 fair value measurements that are developed internally by the Company as of December 31, 2018 and 2017 (dollars in thousands): Fair Value Valuation Unobservable Range (Weighted Average) Assets: 2018 2017 Technique Input 2018 2017 Corporate $ 642,647 $ 173,579 Market comparable securities Liquidity premium 0-5% (1%) 0-2% (1%) EBITDA Multiple 5.9x-7.5x (6.5x) — ABS 77,842 — Market comparable securities Liquidity premium 0-1% (1%) — U.S. government 18,025 22,511 Market comparable securities Liquidity premium 0-1% (1%) 0-1% (1%) State and political subdivisions — 4,616 Market comparable securities Liquidity premium — 1% Other foreign government 5,006 — Market comparable securities Liquidity premium 1% — Equity securities 25,007 — Market comparable securities Liquidity premium 4% — EBITDA Multiple 6.9x-12.3x (7.9x) — Funds withheld at interest- embedded derivatives 109,597 122,194 Total return swap Mortality 0-100% (2%) 0-100% (2%) Lapse 0-35% (10%) 0-35% (9%) Withdrawal 0-5% (3%) 0-5% (3%) CVA 0-5% (1%) 0-5% (1%) Crediting rate 2-4% (2%) 2-4% (2%) Longevity swaps 47,789 40,659 Discounted cash flow Mortality 0-100% (2%) 0-100% (2%) Mortality improvement (10%)-10% (3%) (10%)-10% (3%) Liabilities: Interest-sensitive contract liabilities- embedded derivatives- indexed annuities 776,940 861,758 Discounted cash flow Mortality 0-100% (2%) 0-100% (2%) Lapse 0-35% (10%) 0-35% (9%) Withdrawal 0-5% (3%) 0-5% (3%) Option budget projection 2-4% (2%) 2-4% (2%) Interest-sensitive contract liabilities- embedded derivatives- variable annuities 167,925 152,470 Discounted cash flow Mortality 0-100% (1%) 0-100% (1%) Lapse 0-25% (5%) 0-25% (5%) Withdrawal 0-7% (5%) 0-7% (3%) CVA 0-5% (1%) 0-5% (1%) Long-term volatility 0-27% (13%) 0-27% (8%) Mortality swaps 369 1,683 Discounted cash flow Mortality 0-100% (1%) 0-100% (1%) Valuation Process for Fair Value Measurements Categorized within Level 3 As of December 31, 2018 and 2017, respectively, the Company classified approximately 5.0% and 5.9% of its fixed maturity securities in the Level 3 category. These securities primarily consist of private placement corporate securities, bank loans and Canadian provincial strips with inactive trading markets. The significant unobservable inputs used in the fair value measurement of the Company’s corporate, sovereign, government-backed, other political subdivision and equity security investments include probability of default, liquidity premium and subordination premium. Significant increases (decreases) in any of those inputs in isolation would result in a significantly lower (higher) fair value measurement. Generally, a change in the assumption used for the probability of default is accompanied by a directionally similar change in the assumptions used for the liquidity premium and subordination premium. For securities with a fair value derived using the market comparable pricing valuation technique, liquidity premium is the only significant unobservable input. Other significant unobservable inputs used in the fair value measurement of the Company’s private debt and equity investments include a multiple of earnings before interest, taxes, depreciation and amortization (“EBITDA”). An increase (decrease) in the EBITDA multiple would result in a higher (lower) fair value measurement. The significant unobservable inputs used in the fair value measurement of the Company’s asset and mortgage-backed securities are prepayment rates, probability of default, liquidity premium and loss severity in the event of default. Significant increases (decreases) in any of those inputs in isolation would result in a significantly lower (higher) fair value measurement. Generally, a change in the assumption used for the probability of default is accompanied by a directionally similar change in the assumption used for the liquidity premium and loss severity and a directionally opposite change in the assumption used for prepayment rates. The actuarial assumptions used in the fair value of embedded derivatives, which include assumptions related to lapses, withdrawals, and mortality, are based on experience studies performed by the Company in combination with available industry information and are reviewed on a periodic basis, at least annually. The significant unobservable inputs used in the fair value measurement of embedded derivatives are assumptions associated with policyholder experience and selected capital market assumptions for equity-indexed and variable annuities. The selected capital market assumptions, which include long-term implied volatilities, are projections based on short-term historical information. Changes in interest rates, equity indices, equity volatility, CVA, and actuarial assumptions regarding policyholder experience may result in significant fluctuations in the value of embedded derivatives. Fair value measurements associated with funds withheld reinsurance treaties are generally not materially sensitive to changes in unobservable inputs associated with policyholder experience. The primary drivers of change in these fair values are related to movements of credit spreads, which are generally observable. Increases (decreases) in market credit spreads tend to decrease (increase) the fair value of embedded derivatives. Increases (decreases) in the CVA assumption tend to decrease (increase) the magnitude of the fair value of embedded derivatives. Fair value measurements associated with variable annuity treaties are sensitive to both capital markets inputs and policyholder experience inputs. Increases (decreases) in lapse rates tend to decrease (increase) the value of the embedded derivatives associated with variable annuity treaties. Increases (decreases) in the long-term volatility assumption tend to increase (decrease) the fair value of embedded derivatives. Increases (decreases) in the CVA assumption tend to decrease (increase) the magnitude of the fair value of embedded derivatives. The actuarial assumptions used in the fair value of longevity and mortality swaps include assumptions related to the level and volatility of mortality. The assumptions are based on studies performed by the Company in combination with available industry information and are reviewed on a periodic basis, at least annually. Changes in Level 3 Assets and Liabilities Assets and liabilities transferred into Level 3 are due to a lack of observable market transactions and price information. Assets and liabilities are transferred out of Level 3 when circumstances change such that significant inputs can be corroborated with market observable data. This may be due to a significant increase in market activity for the asset or liability, a specific event, or one or more significant input(s) becoming observable. Transfers out of Level 3 were primarily the result of the Company obtaining observable pricing information or a third party pricing quotation that appropriately reflects the fair value of those assets and liabilities. The Company also transferred equity securities with a fair value of approximately $38.9 million into Level 3 as a result of the adoption of the new accounting guidance for the recognition and measurement of equity securities. The reconciliations for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) are as follows (dollars in thousands): For the year ended December 31, 2018: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,337,272 $ 593,942 $ 107,882 $ 123,474 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (1,045 ) 13,965 (129 ) 224 Investment related gains (losses), net (4,651 ) — 312 1,910 Included in other comprehensive income (32,983 ) (79,783 ) (1,786 ) (1,344 ) Purchases (1) 509,134 — 52,279 42,120 Sales (1) (106,005 ) — (4,961 ) (462 ) Settlements (1) (273,898 ) — (4,633 ) (57,476 ) Transfers into Level 3 9,948 — 3,031 73,289 Transfers out of Level 3 (106,847 ) — (145,140 ) (86,163 ) Fair value, end of period $ 1,330,925 $ 528,124 $ 6,855 $ 95,572 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (998 ) $ 13,965 $ 3 $ 209 Investment related gains (losses), net (6,320 ) — — — For the year ended December 31, 2018 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 3,234 $ 22,511 $ 41,203 $ 5,092 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses — (423 ) 9 — Investment related gains (losses), net 1 (208 ) — — Included in other comprehensive income (65 ) (436 ) 66 (86 ) Purchases (1) — 418 — — Sales (1) (1,751 ) — — — Settlements (1) (5 ) (3,

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2018
Reinsurance Disclosures [Abstract]
Reinsurance	REINSURANCE In the normal course of business, the Company seeks to limit its exposure to loss on any single insured and to recover a portion of benefits paid by ceding reinsurance to other insurance enterprises or reinsurers under excess coverage and coinsurance contracts. In the individual life markets, the Company retains a maximum of $8.0 million of coverage per individual life. Claims in excess of this retention amount are retroceded to retrocessionaires; however, the Company remains fully liable to the ceding company for the entire amount of risk it assumes. In certain limited situations the Company has retained more than $8.0 million per individual policy. The Company enters into agreements with other reinsurers to mitigate the residual risk related to the over-retained policies. Additionally, due to some lower face amount reinsurance coverage provided by the Company in addition to individual life, such as group life, disability and health, under certain circumstances, the Company could potentially incur net claims totaling more than $8.0 million per individual life. Retrocession reinsurance treaties do not relieve the Company from its obligations to direct writing companies. Failure of retrocessionaires to honor their obligations could result in losses to the Company. Consequently, allowances would be established for amounts deemed uncollectible. At December 31, 2018 and 2017 , no allowances were deemed necessary. The Company regularly evaluates the financial condition of the insurance companies from which it assumes and to which it cedes reinsurance. Retrocessions are arranged through the Company’s retrocession pools for amounts in excess of the Company’s retention limit. As of December 31, 2018 and 2017 , all rated retrocession pool participants followed by the A.M. Best Company were rated “A- (excellent)” or better except one pool member that was rated “ B+ .” The Company verifies retrocession pool participants’ ratings on a quarterly basis. For a majority of the retrocessionaires that were not rated, security in the form of letters of credit or trust assets has been posted. In addition, the Company performs annual financial reviews of its retrocessionaires to evaluate financial stability and performance. In addition to its third party retrocessionaires, various RGA reinsurance subsidiaries retrocede amounts in excess of their retention to affiliated subsidiaries. The following table presents information for the Company’s ceded reinsurance receivable assets, including the respective amount and A.M. Best rating for each reinsurer representing in excess of five percent of the total as of December 31, 2018 or 2017 (dollars in thousands): 2018 2017 Reinsurer A.M. Best Rating Amount % of Total Amount % of Total Reinsurer A A+ $ 303,036 40.0 % $ 301,478 38.6 % Reinsurer B A+ 193,324 25.5 203,898 26.1 Reinsurer C A 69,885 9.2 67,723 8.7 Reinsurer D A+ 40,004 5.3 40,528 5.2 Reinsurer E A++ 36,600 4.8 40,592 5.2 Other reinsurers 114,723 15.2 127,808 16.2 Total $ 757,572 100.0 % $ 782,027 100.0 % Included in the total ceded reinsurance receivables balance were $242.8 million and $243.8 million of claims recoverable, of which $17.4 million and $1.9 million were in excess of 90 days past due, as of December 31, 2018 and 2017 , respectively. The effect of reinsurance on net premiums is as follows (dollars in thousands): Years ended December 31, 2018 2017 2016 Direct $ 62,526 $ 61,571 $ 57,562 Reinsurance assumed 11,341,284 10,642,462 10,049,587 Reinsurance ceded (860,034 ) (862,903 ) (858,278 ) Net premiums $ 10,543,776 $ 9,841,130 $ 9,248,871 The effect of reinsurance on claims and other policy benefits as follows (dollars in thousands): Years ended December 31, 2018 2017 2016 Direct $ 107,405 $ 104,447 $ 105,435 Reinsurance assumed 9,997,173 9,281,590 8,621,647 Reinsurance ceded (785,649 ) (867,120 ) (733,707 ) Net claims and other policy benefits $ 9,318,929 $ 8,518,917 $ 7,993,375 The effect of reinsurance on life insurance in force is shown in the following schedule (dollars in millions): Direct Assumed Ceded Net Assumed/Net % December 31, 2018 $ 1,363 $ 3,329,181 $ 186,172 $ 3,144,372 105.9 % December 31, 2017 1,462 3,297,275 205,529 3,093,208 106.6 December 31, 2016 1,576 3,062,525 214,727 2,849,374 107.5 At December 31, 2018 and 2017 , respectively, the Company provided approximately $18.1 billion and $16.2 billion of financial reinsurance, as measured by pre-tax statutory surplus, risk based capital and other financial reinsurance structures, to other insurance companies under financial reinsurance transactions to assist ceding companies in meeting applicable regulatory requirements. Generally, such financial reinsurance is provided by the Company committing cash or assuming insurance liabilities, which are collateralized by future profits on the reinsured business. The Company earns a fee based on the amount of net outstanding financial reinsurance. Reinsurance agreements, whether facultative or automatic, may provide for recapture rights on the part of the ceding company. Recapture rights permit the ceding company to reassume all or a portion of the risk formerly ceded to the reinsurer after an agreed-upon period of time, generally 10 years, or in some cases due to changes in the financial condition or ratings of the reinsurer. Recapture of business previously ceded does not affect premiums ceded prior to the recapture of such business, but would reduce premiums in subsequent periods. Additionally, some treaties give the ceding company the right to request the Company to place assets in trust for their benefit to support their reserve credits, in the event of a downgrade of the Company’s ratings to specified levels, generally non-investment grade levels, or if minimum levels of financial condition are not maintained. As of December 31, 2018 and 2017 , these treaties had approximately $3,421.0 million and $2,901.1 million , respectively, in statutory reserves. Assets placed in trust continue to be owned by the Company, but their use is restricted based on the terms of the trust agreement. Securities with an amortized cost of $2,910.2 million and $2,214.1 million were held in trust to satisfy collateral requirements for reinsurance business for the benefit of certain RGA subsidiaries at December 31, 2018 and 2017 , respectively. In addition, the Company’s collateral financing operations have asset in trust requirements. See Note 14 – “Collateral Finance and Securitization Notes” for additional information. Securities with an amortized cost of $20,072.7 million and $15,584.3 million , as of December 31, 2018 and 2017 , respectively, were held in trust to satisfy collateral requirements under certain third-party reinsurance treaties. Under certain conditions, RGA may be obligated to move reinsurance from one RGA subsidiary company to another or make payments under the treaty. These conditions include change in control or ratings of the subsidiary, insolvency, nonperformance under a treaty, or loss of reinsurance license of such subsidiary.

Deferred Policy Acquisition Cos

Deferred Policy Acquisition Costs	12 Months Ended
	Dec. 31, 2018
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred Policy Acquisition Costs	DEFERRED POLICY ACQUISITION COSTS The following reflects the amounts of policy acquisition costs deferred and amortized (dollars in thousands): Years ended December 31, 2018 2017 2016 Balance, beginning of year $ 3,239,824 $ 3,338,605 $ 3,392,437 Capitalization 607,743 348,470 350,233 Amortization (including interest) (437,696 ) (432,474 ) (341,115 ) Change in value of embedded derivatives 14,658 (70,392 ) (40,077 ) Attributed to unrealized investment gains (losses) 26,608 (8,220 ) (3,541 ) Foreign currency translation (53,367 ) 63,835 (19,332 ) Balance, end of year $ 3,397,770 $ 3,239,824 $ 3,338,605 Some reinsurance agreements involve reimbursing the ceding company for allowances and commissions in excess of first-year premiums. These amounts represent acquisition costs and are capitalized to the extent deemed recoverable from the future premiums and amortized against future profits of the business. This type of agreement presents a risk to the extent that the business lapses faster than originally anticipated, resulting in future profits being insufficient to recover the Company’s investment.

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax	INCOME TAX The Tax Cuts and Jobs Act (“U.S. Tax Reform”) was signed into law on December 22, 2017. U.S. Tax Reform made broad changes to the U.S. tax code, including (1) reducing the U.S. federal corporate tax rate from 35 percent to 21 percent; (2) imposed a one-time transition tax on certain unrepatriated earnings of foreign subsidiaries; (3) generally eliminated U.S. federal income taxes on dividends from foreign subsidiaries; (4) eliminated the corporate alternative minimum tax (“AMT”) and changed how existing AMT credits can be realized; (5) created the base erosion anti-abuse tax (“BEAT”); (6) established a new provision designed to tax global intangible low-taxed income (“GILTI”), which allows for the possibility of using foreign tax credits and a deduction of up to 50% to offset the income tax liability (subject to some limitations); and (7) modified the rules related to uses and limitations of net operating loss carryforwards created in tax years beginning after December 31, 2017. In connection with the Company’s initial analysis of the impact of U.S. Tax Reform, it recorded a discrete provisional net tax benefit of $1,033.8 million in the period ending December 31, 2017. This estimated net benefit primarily consisted of the U.S. federal rate reduction from 35% to 21% applied to the net deferred tax liability. The Company provisionally estimated there would be no one-time transition tax on unrepatriated earnings of foreign subsidiaries. Further, as a result of U.S. Tax Reform, the Company established a valuation allowance of $58.9 million related to U.S. foreign tax credit carryforwards. The valuation allowance related to the Company’s interpretation of the changes in the ability to use existing foreign tax credit carryforwards against future foreign branch profits. The SEC issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for the tax effects of U.S. Tax Reform. SAB 118 provides a measurement period that should not extend beyond one year from U.S. Tax Reform enactment date for companies to complete the accounting under ASC 740. The Company completed its accounting for the effects of U.S. Tax Reform within the measurement period during the fourth quarter of 2018. The Company’s refinement of the provisional estimates for the impact of U.S. Tax Reform resulted in the aforementioned valuation allowance adjustment and other immaterial adjustments to the amounts originally estimated. Upon review of the Proposed Treasury Regulations issued during the year and completion of the accumulated and current earnings and profits calculations of the Company’s foreign subsidiaries, no adjustment to the provisional estimate of the transition tax on unrepatriated earnings was necessary. The valuation allowance established with U.S. Tax Reform was released in 2018. The Company recognized an uncertain tax position due to the expiration of the statute of limitations. Concurrent with this recognition of a prior year tax position, the Company established a new uncertain tax liability. The foreign tax credits were used to offset the new uncertain tax liability, hence a valuation allowance was no longer necessary. Under GAAP, the Company is allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to the GILTI as a current-period expense when incurred (“the period cost method”) or (2) factoring such amounts into a Company’s measurement of its deferred taxes (“the deferred method”). The Company made a policy election to account for GILTI as a period cost. For the year ended December 31, 2018, the Company is not subject to the BEAT. The Company continues to monitor guidance as it is issued; however, it does not expect changes in guidance to result in a BEAT liability. The effective tax rate for 2018 was lower than the U.S. Statutory rate of 21.0% primarily as a result of the release of a valuation allowance on foreign tax credits, which partially offset tax expense related to GILTI and valuation allowance increases. The effective tax rate for 2017 was lower than the U.S. Statutory rate of 35% primarily as a result of accounting for the effects of U.S. Tax Reform and income generated in non-U.S. jurisdictions with lower tax rates than the U.S. See the table below for additional information. Pre-tax income for the years ended December 31, 2018, 2017 and 2016 consists of the following (dollars in thousands): 2018 2017 2016 Pre-tax income - U.S. $ 626,197 $ 870,532 $ 758,496 Pre-tax income - foreign 219,623 272,283 285,450 Total pre-tax income $ 845,820 $ 1,142,815 $ 1,043,946 The provision for income tax expense for the years ended December 31, 2018, 2017 and 2016 consists of the following (dollars in thousands): 2018 2017 2016 Current income tax expense (benefit): U.S. $ 78,431 $ 131,108 $ 1,020 U.S. Tax Reform (68,080 ) — — Foreign 43,120 36,830 47,706 Total current 53,471 167,938 48,726 Deferred income tax expense (benefit): U.S. 62,890 159,853 273,928 U.S. Tax Reform 5,907 (1,033,755 ) — Foreign 7,710 26,598 19,849 Total deferred 76,507 (847,304 ) 293,777 Total provision for income taxes $ 129,978 $ (679,366 ) $ 342,503 The Company’s effective tax rate differed from the U.S. federal income tax statutory rate of 21%, 35%, and 35% as a result of the following for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): 2018 2017 2016 Tax provision at U.S. statutory rate $ 177,622 $ 399,985 $ 365,381 Increase (decrease) in income taxes resulting from: U.S. Tax Reform (62,173 ) (1,033,755 ) — Foreign tax rate differing from U.S. tax rate 4,526 (21,867 ) (13,974 ) Differences in tax basis in foreign jurisdictions (23,257 ) (23,324 ) (17,770 ) Deferred tax valuation allowance 23,144 29,458 10,963 Amounts related to audit contingencies 1,516 (7,184 ) 111 Equity compensation excess benefit (6,103 ) (10,532 ) — Corporate rate changes 1,008 (6,065 ) — GILTI, net of credits 10,400 — — Subpart F for non-full inclusion companies 583 1,528 1,783 Foreign tax credits (2,544 ) (1,681 ) (1,683 ) Return to provision adjustments (1,305 ) (4,674 ) (1,473 ) Other, net 6,561 (1,255 ) (835 ) Total provision for income taxes $ 129,978 $ (679,366 ) $ 342,503 Effective tax rate 15.4 % (59.4 )% 32.8 % Total income taxes for the years ended December 31, 2018, 2017 and 2016 were as follows (dollars in thousands): 2018 2017 2016 Provision for income taxes $ 129,978 $ (679,366 ) $ 342,503 Income tax from OCI and additional paid-in-capital: Net unrealized holding gain (loss) on debt and equity securities recognized for financial reporting purposes (367,933 ) 306,849 157,929 Exercise of stock options — — (162 ) Foreign currency translation 19,101 (42,153 ) 21,081 Unrealized pension and post retirement 134 404 1,772 Total income taxes provided $ (218,720 ) $ (414,266 ) $ 523,123 The tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities at December 31, 2018 and 2017 , are presented in the following tables (dollars in thousands): 2018 2017 Deferred income tax assets: Nondeductible accruals $ 86,092 $ 80,905 Differences between tax and financial reporting amounts concerning certain reinsurance transactions 102,014 96,043 Differences in the tax basis of cash and invested assets 28,398 557 Investment income differences 80,200 43,230 Deferred acquisition costs capitalized for tax 124,707 88,531 Net operating loss carryforward 405,958 535,374 Capital loss and tax credit carryforwards 32,897 102,143 Subtotal 860,266 946,783 Valuation allowance (181,110 ) (226,884 ) Total deferred income tax assets 679,156 719,899 Deferred income tax liabilities: Deferred acquisition costs capitalized for financial reporting 843,328 627,378 Differences between tax and financial reporting amounts concerning certain reinsurance transactions 1,151,419 1,547,101 Differences in the tax basis of cash and invested assets 345,836 674,569 Investment income differences 9,493 1,858 Differences in foreign currency translation 52,928 33,803 Anticipated future tax credit reduction 25,433 — Total deferred income tax liabilities 2,428,437 2,884,709 Net deferred income tax liabilities $ 1,749,281 $ 2,164,810 Balance sheet presentation of net deferred income tax liabilities: Included in other assets $ 49,519 $ 33,499 Included in deferred income taxes 1,798,800 2,198,309 Net deferred income tax liabilities $ 1,749,281 $ 2,164,810 As of December 31, 2018 , the valuation allowance against deferred tax assets was $181.1 million . During 2018, a valuation allowance on the U.S. Foreign tax credit carryforwards of $65.1 million was released. This release partially offset a $24.5 million increase to the valuation allowance related to the net operating losses of RGA Reinsurance Company of Australia Limited (“RGA Australia”) and increases and decreases to the valuation allowance in jurisdictions where the Company does not have a history of earnings. Further movement in the valuation allowance includes foreign currency translation and reclassifications with other deferred tax assets of ($12.8) million . As of December 31, 2017, the valuation allowance against deferred tax assets was approximately $226.9 million . During 2017 a valuation allowance was established on the U.S. Foreign tax credit carryforwards of $65.1 million , RGA Australia net operating losses of $20.1 million , as well as on the deferred tax assets of other jurisdictions of $3.3 million . Further movement in the valuation allowance includes foreign currency translation and reclassifications with other deferred tax assets of $10.6 million and ($5.6) million , respectively. The other significant components of the valuation allowance relate to a partial valuation allowance on the net operating loss carryforwards in RGA Australia and the foreign tax credit carryforwards in RGA International Reinsurance Company dac (“RGA International”). A valuation allowance also exists against the deferred tax assets of other branches and legal entities most of which there is no history of earnings in recent years. The earnings of substantially all of the Company’s foreign subsidiaries have been permanently reinvested in foreign operations. No provision has been made for U.S. tax or foreign withholding taxes that may be applicable upon any repatriation or sale. At December 31, 2018 and 2017 , the financial reporting basis in excess of the tax basis for which no deferred taxes have been recognized was approximately $1,364.1 million and $1,442.9 million , respectively. As U.S. Tax Reform generally eliminates U.S. federal income taxes on dividends from foreign subsidiaries, the Company does not expect to incur material income taxes if these funds are repatriated. During 2018, 2017 and 2016 , the Company received federal and foreign income tax refunds of approximately $2.4 million , $11.6 million and $6.9 million , respectively. The Company made cash income tax payments of approximately $144.1 million , $48.7 million and $68.0 million in 2018, 2017 and 2016 , respectively. The following table presents consolidated net operating losses (“NOL”) as of December 31, 2018 (dollars in millions): 2018 NOL with no expiration and with no valuation allowance $ 52 NOL with a full valuation allowance 167 NOL with no expiration and a partial valuation allowance 396 NOL with expiration dates between 2029 & 2035 with no valuation allowance 1,118 Total net operating loss carryforwards $ 1,733 These net operating losses, other than the net operating losses for which there is a valuation allowance, are expected to be utilized in the normal course of business during the period allowed for carryforwards and in any event, are not expected to be lost, due to the application of tax planning strategies that management would utilize. As of December 31, 2018 the Company had foreign tax credit carryforwards of $27.8 million in Ireland and as of December 31, 2017, the Company had $152.0 million of foreign tax credit carryforwards in the U.S. and Ireland. The Ireland foreign tax credit carryforward has a full valuation allowance. The Company files income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. The Company is under continuous examination by the Internal Revenue Service and is subject to audit by taxing authorities in other foreign jurisdictions in which the Company has significant business operations. The income tax years under examination vary by jurisdiction. The Company is no longer subject to U.S. federal income tax examinations by tax authorities for years prior to 2015, Canadian tax authorities for years prior to 2014 and with a few exceptions, the Company is no longer subject to state and foreign income tax examinations by tax authorities for years prior to 2013. As of December 31, 2018 , the Company’s total amount of unrecognized tax benefits was $324.6 million and the total amount of unrecognized tax benefits that would affect the effective tax rate, if recognized, was $12.8 million . Management believes there will be no material impact to the Company’s effective tax rate related to unrecognized tax benefits over the next 12 months. A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31, 2018, 2017 and 2016 , is as follows (dollars in thousands): Total Unrecognized Tax Benefits 2018 2017 2016 Beginning balance, January 1 $ 321,224 $ 297,290 $ 296,213 Accounting for business combinations 521 — — Additions for tax positions of prior years 255,970 247,596 226,720 Reductions for tax positions of prior years (256,587 ) (246,894 ) (229,719 ) Additions for tax positions of current year 3,682 36,438 4,186 Payment on deposit (185 ) — — Settlements with tax authorities — (13,206 ) (110 ) Ending balance, December 31 $ 324,625 $ 321,224 $ 297,290 The Company recognized a benefit in interest expense associated with uncertain tax positions in 2018, 2017 and 2016 of $3.3 million , $5.0 million and $8.4 million , respectively. Additionally, the Company recognized penalties of $0.3 million in 2016. As of December 31, 2018 and 2017 , the Company had $11.6 million and $15.1 million , respectively, of accrued interest related to unrecognized tax benefits. There are no penalties accrued as of December 31, 2018 or December 31, 2017.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS Certain subsidiaries of the Company are sponsors or administrators of both qualified and non-qualified defined benefit pension plans (“Pension Plans”). The largest of these plans is a non-contributory qualified defined benefit pension plan sponsored by RGA Reinsurance Company (“RGA Reinsurance”) that covers U.S. employees. The benefits under the Pension Plans are generally based on years of service and compensation levels. The Company also provides select health care and life insurance benefits for certain retired employees. The health care benefits are provided through a self-insured welfare benefit plan. Employees become eligible for these benefits if they meet minimum age and service requirements. The retiree’s cost for health care benefits varies depending upon the credited years of service. Effective January 1, 2017, employees hired in the U. S. are not eligible for retiree health care benefits. The effect of the amendment was recorded in 2016 in AOCI and is being amortized through prior service cost. Virtually all retirees, or their beneficiaries, contribute a portion of the total cost of postretirement health benefits. Prepaid benefit costs and accrued benefit liabilities are included in other assets and other liabilities, respectively, in the Company’s consolidated balance sheets. A December 31 measurement date is used for all of the defined benefit and postretirement plans. The status of these plans as of December 31, 2018 and 2017 is summarized below (dollars in thousands): December 31, Pension Benefits Other Benefits 2018 2017 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 172,143 $ 161,955 $ 70,198 $ 60,524 Service cost 12,502 10,686 3,028 2,543 Interest Cost 5,405 5,326 2,319 2,118 Participant contributions — — 432 354 Amendments — 159 — — Actuarial (gains) losses (1,045 ) 11,336 (7,172 ) 5,510 Settlement (gains) losses — (438 ) — — Settlements — (12,907 ) — — Benefits paid (7,801 ) (5,974 ) (1,409 ) (851 ) Foreign exchange translations and other adjustments (2,600 ) 2,000 — — Benefit obligation at end of year $ 178,604 $ 172,143 $ 67,396 $ 70,198 December 31, Pension Benefits Other Benefits 2018 2017 2018 2017 Change in plan assets: Fair value of plan assets at beginning of year $ 103,236 $ 84,770 $ — $ — Actual return on plan assets (6,464 ) 14,481 — — Employer contributions 13,590 22,866 977 497 Participant contributions — — 432 354 Disbursement for settlements — (12,907 ) — — Benefits paid and expenses (7,801 ) (5,974 ) (1,409 ) (851 ) Fair value of plan assets at end of year $ 102,561 $ 103,236 $ — $ — Funded status at end of year $ (76,043 ) $ (68,907 ) $ (67,396 ) $ (70,198 ) December 31, Qualified Plans Non-Qualified Plans (1) Total 2018 2017 2018 2017 2018 2017 Aggregate fair value of plan assets $ 102,561 $ 103,236 $ — $ — $ 102,561 $ 103,236 Aggregate projected benefit obligations 112,093 107,072 66,511 65,071 178,604 172,143 Under funded $ (9,532 ) $ (3,836 ) $ (66,511 ) $ (65,071 ) $ (76,043 ) $ (68,907 ) (1) For non-qualified plans, there are no required funding levels. December 31, Pension Benefits Other Benefits 2018 2017 2018 2017 Amounts recognized in accumulated other comprehensive income: Net actuarial loss $ 48,744 $ 40,058 $ 25,923 $ 35,672 Net prior service cost (credit) 436 804 (10,491 ) (11,806 ) Total $ 49,180 $ 40,862 $ 15,432 $ 23,866 The following table presents information for qualified and non-qualified pension plans with a projected benefit obligation in excess of plan assets as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Projected benefit obligation $ 178,604 $ 172,143 Fair value of plan assets 102,561 103,236 The following table presents information for pension plans with an accumulated benefit obligation in excess of plan assets as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Accumulated benefit obligation $ 174,400 $ 169,705 Fair value of plan assets 102,561 103,236 The components of net periodic benefit cost, included in other operating expenses on the consolidated statements of income, and other changes in plan assets and benefit obligations recognized in other comprehensive income were as follows (dollars in thousands): Pension Benefits Other Benefits 2018 2017 2016 2018 2017 2016 Net periodic benefit cost: Service cost $ 12,502 $ 10,686 $ 10,319 $ 3,028 $ 2,543 $ 2,883 Interest cost 5,405 5,326 4,790 2,319 2,118 2,259 Expected return on plan assets (7,535 ) (6,215 ) (5,138 ) — — — Amortization of net actuarial losses 3,728 4,382 4,323 2,577 1,992 1,827 Amortization of prior service cost (credit) 344 344 294 (1,315 ) (1,315 ) (622 ) Settlements — 4,785 1,026 — — — Net periodic benefit cost 14,444 19,308 15,614 6,609 5,338 6,347 Other changes in plan assets and benefit obligations recognized in other comprehensive income: Net actuarial (gains) losses 12,954 2,633 8,785 (7,172 ) 5,507 6,228 Amortization of net actuarial (losses) (3,728 ) (4,382 ) (4,323 ) (2,577 ) (1,992 ) (1,827 ) Amortization of prior service (cost) credit (344 ) (344 ) (294 ) 1,315 1,315 622 Settlements — (4,785 ) (1,026 ) — — — Prior service cost (credit) — 159 — — — (13,743 ) Foreign exchange translations and other adjustments (565 ) 759 707 — — — Total recognized in other comprehensive income 8,317 (5,960 ) 3,849 (8,434 ) 4,830 (8,720 ) Total recognized in net periodic benefit cost and other comprehensive income $ 22,761 $ 13,348 $ 19,463 $ (1,825 ) $ 10,168 $ (2,373 ) During 2019, the Company expects to contribute $16.3 million and $1.5 million to the pension plans and other benefit plans, respectively. The following benefit payments, which reflect expected future service as appropriate, are expected to be paid (dollars in thousands): Pension Benefits Other Benefits 2019 $ 9,977 $ 1,528 2020 12,013 1,835 2021 11,663 2,209 2022 14,229 2,633 2023 14,128 3,009 2024-2028 77,832 20,359 Assumptions Weighted average assumptions used to determine the accumulated benefit obligation and net benefit cost or income were as follows: Pension Benefits Other Benefits 2018 2017 2016 2018 2017 2016 Discount rate used to determine benefit obligation 4.02 % 3.40 % 3.80 % 4.17 % 3.56 % 4.10 % Discount rate used to determine net benefit cost or income 3.41 % 3.81 % 3.95 % 3.56 % 4.10 % 4.43 % Expected long-term rate of return on plan assets 7.35 % 7.35 % 7.35 % — % — % — % Rate of compensation increases 4.17 % 4.16 % 4.08 % — % — % — % The expected rate of return on plan assets is based on anticipated performance of the various asset sectors in which the plan invests, weighted by target allocation percentages. Anticipated future performance is based on long-term historical returns of the plan assets by sector, adjusted for the long-term expectations on the performance of the markets. While the precise expected return derived using this approach may fluctuate from year to year, the policy is to hold this long-term assumption constant as long as it remains within reasonable tolerance from the derived rate. This process is consistent for all plan assets as all the assets are invested in mutual funds. The assumed health care cost trend rates used in measuring the accumulated non-pension post-retirement benefit obligation were as follows: December 31, 2018 2017 Pre-Medicare eligible claims 8% down to 5% in 2024 9% down to 5% in 2024 Medicare eligible claims 8% down to 5% in 2024 9% down to 5% in 2024 Plan Assets Target allocations of U.S. qualified pension plan assets are determined with the objective of maximizing returns and minimizing volatility of net assets through adequate asset diversification and partial liability immunization. Adjustments are made to target allocations based on the Company’s assessment of the effect of economic factors and market conditions. The target allocations for plan assets are 60% equity securities and 40% debt securities as of December 31, 2018 and 2017 . The Company’s plan assets are primarily invested in mutual funds. The mutual funds include holdings of S&P 500 securities, large-cap securities, mid-cap securities, small-cap securities, international securities, corporate debt securities, U.S. and other government securities, mortgage-related securities and cash. Equity and debt securities are exposed to various risks, such as interest rate risk, credit risk and overall market volatility. Due to the level of risk associated with certain investment securities, changes in the values of investment securities will occur and any change would affect the amounts reported in the financial statements. The fair values of the Company’s qualified pension plan assets as of December 31, 2018 and 2017 are summarized below (dollars in thousands): December 31, 2018 Fair Value Measurement Using: Total Level 1 Level 2 Level 3 Mutual Funds (1) $ 102,414 $ 102,414 $ — $ — Cash 147 147 — — Total $ 102,561 $ 102,561 $ — $ — (1) Mutual funds were invested 25% in U.S. equity funds, 42% in U.S. fixed income funds, 17% in non-U.S. equity funds and 16% in other. December 31, 2017 Fair Value Measurement Using: Total Level 1 Level 2 Level 3 Mutual Funds (2) $ 103,106 $ 103,106 $ — $ — Cash 130 130 — — Total $ 103,236 $ 103,236 $ — $ — (2) Mutual funds were invested 27% in U.S. equity funds, 36% in U.S. fixed income funds, 22% in non-U.S. equity funds and 15% in other. As of December 31, 2018 and 2017 , the Company classified all of its qualified pension plan assets in the Level 1 category as quoted prices in active markets are available for these assets. See Note 6 – “Fair Value of Asset and Liabilities” for additional detail on the fair value hierarchy. Savings and Investment Plans Certain subsidiaries of RGA also sponsor savings and investment plans under which a portion of employee contributions are matched. Subsidiary contributions to these plans were $15.3 million , $14.2 million and $9.9 million in 2018, 2017 and 2016 , respectively.

Financial Condition and Net Inc

Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries	12 Months Ended
	Dec. 31, 2018
Statutory Basis [Abstract]
Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries	FINANCIAL CONDITION AND NET INCOME ON A STATUTORY BASIS – SIGNIFICANT SUBSIDIARIES The domestic and foreign insurance subsidiaries of RGA prepare their statutory financial statements in conformity with statutory accounting practices prescribed or permitted by the applicable state insurance department or local regulatory authority, which vary materially from statements prepared in accordance with GAAP. Prescribed statutory accounting practices in the U.S. include publications of the National Association of Insurance Commissioners (“NAIC”), as well as state laws, local regulations and general administrative rules. The differences between statutory financial statements and financial statements prepared in accordance with GAAP vary between jurisdictions. The principal differences between GAAP and NAIC are that statutory financial statements do not reflect deferred policy acquisition costs and limit deferred tax assets, life benefit reserves predominately use interest rate and mortality assumptions prescribed by the NAIC and local regulatory agencies, bonds are generally carried at amortized cost and reinsurance assets and liabilities are presented net of reinsurance. Statutory net income, and capital and surplus of the Company’s insurance subsidiaries, determined in accordance with statutory accounting practices prescribed by the applicable state insurance department or local regulatory authority are as follows (dollars in thousands): Statutory Capital & Surplus Statutory Net Income (Loss) 2018 2017 2018 2017 2016 RGA Americas Reinsurance Company, Ltd. $ 4,298,368 $ 4,833,890 $ 208,999 $ 624,145 $ 282,226 RGA Reinsurance (U.S.) 2,078,654 1,584,007 659,941 138,359 148,576 Reinsurance Company of Missouri 2,053,379 1,557,453 (24,907 ) (183,136 ) 272,038 RGA Reinsurance Company (Barbados) Ltd. 1,169,790 1,278,006 48,779 309,346 95,859 RGA Atlantic Reinsurance Company Ltd. 1,083,181 812,307 256,080 213,511 110,172 RGA Life Reinsurance Company of Canada 896,760 1,006,190 (37,922 ) 25,971 13,947 RGA Australia 433,406 476,528 (37,208 ) 78,497 (7,694 ) Other insurance subsidiaries 2,572,307 2,694,317 345,249 65,658 130,289 Each U.S. domestic insurance subsidiary’s state of domicile imposes minimum risk-based capital (“RBC”) requirements that were developed by the NAIC. The formulas for determining the amount of RBC specify various weighting factors that are applied to financial balances or various levels of activity based on the perceived degree of risk. Regulatory compliance is determined by a ratio of total adjusted capital, as defined by the NAIC, to authorized control level RBC, as defined by the NAIC. Companies below specific trigger points or ratios are classified within certain levels, each of which requires specified corrective action. Each of RGA’s U.S. domestic insurance subsidiaries exceeded the minimum RBC requirements for all periods presented herein. These requirements do not represent a significant constraint for the payment of dividends by RGA’s U.S. domestic insurance companies. The licensing orders of the Company’s special purpose companies stipulate a minimum amount of capital required based on the purpose of the entity and the underlying business. These companies are subject to enhanced oversight by the regulator which includes filing detailed plans of operations before commencing operations or making material changes to existing agreements or entering into new agreements. Each of the Company’s Special Purpose Life Reinsurance Captives (“SPLRC”) exceeded the minimum capital requirements for all periods presented herein. The Company’s foreign insurance subsidiaries prepare financial statements in accordance with local regulatory requirements. The regulatory authorities in these foreign jurisdictions establish some form of minimum regulatory capital and surplus requirements. All of the Company’s foreign insurance subsidiaries have regulatory capital and surplus that exceed the local minimum requirements. These requirements do not represent a significant constraint for the payment of dividends by the Company’s foreign insurance companies. The state of domicile of certain of the Company’s SPLRCs follow prescribed accounting practices differing from NAIC statutory accounting practices (“NAIC SAP”) applicable to their statutory financial statements. Specifically, these prescribed practices require that surplus note interest accrued but not approved for payment be reported as a direct reduction of surplus and an addition to the surplus note balance. Under NAIC SAP, surplus note interest is not to be reported until approved for payment and is reported as a reduction of net investment income in the Summary of Operations. In addition, these prescribed practices allow the SPLRC to reflect letters of credit issued for its benefit as an admitted asset and a direct credit to unassigned surplus. Under NAIC SAP, letters of credit issued on behalf of the reporting company are not reported on the balance sheet. A reconciliation of the Company’s surplus between NAIC SAP and practices prescribed by the state of domicile is shown below (dollars in thousands): December 31, 2018 2017 Prescribed practice – surplus note $ 624,266 $ 726,531 Prescribed practice – letters of credit (976,100 ) (960,100 ) Surplus (deficit) – NAIC SAP $ (351,834 ) $ (233,569 ) Reinsurance Company of Missouri (“RCM”), RGA Reinsurance and Chesterfield Reinsurance Company (“Chesterfield Re”) are subject to Missouri statutory provisions that restrict the payment of dividends. They may not pay dividends in any 12 -month period in excess of the greater of the prior year’s statutory net gain from operations or 10% of statutory capital and surplus at the preceding year-end, without regulatory approval. Aurora National Life Assurance Company (“Aurora National”) is subject to California statutory provisions that are identical to those imposed by Missouri regarding the ability of Aurora National to pay dividends to RGA Reinsurance. The applicable statutory provisions only permit an insurer to pay a shareholder dividend from unassigned surplus. As of January 1, 2018, RGA Reinsurance could pay maximum dividends, without prior approval, of approximately $653.9 million . Any dividends paid by RGA Reinsurance would be paid to RCM, its parent company, which in turn has restrictions related to its ability to pay dividends to RGA. Chesterfield Re would pay dividends to its immediate parent Chesterfield Financial Holdings LLC, (“Chesterfield Financial”), which would in turn pay dividends to RCM, subject to the terms of the indenture for the embedded value securitization transaction, in which Chesterfield Financial cannot declare or pay any dividends so long as any private placement notes are outstanding. The Missouri Department of Insurance, Financial Institution and Professional Registration, allows RCM to pay a dividend to RGA to the extent RCM received the dividend from its subsidiaries, without limitation related to the level of unassigned surplus. Dividend payments from other subsidiaries are subject to regulations in the jurisdiction of domicile, which are generally based on their earnings and/or capital level. Dividend payments from non-U.S. operations are subject to similar restrictions established by local regulators. The non-U.S. regulatory regimes also commonly limit the dividend payments to the parent to a portion of the prior year’s statutory income, as determined by the local accounting principles. The regulators of the Company’s non-U.S. operations may also limit or prohibit profit repatriations or other transfers of funds to the U.S. if such transfers are deemed to be detrimental to the solvency or financial strength of the non-U.S. operations, or for other reasons. Most of the non-U.S. operating subsidiaries are second tier subsidiaries that are owned by various non-U.S. holding companies. The capital and rating considerations applicable to the first tier subsidiaries may also impact the dividend flow to RGA. There are no regulatory restrictions that limit the payment of dividends by RGA, except those generally applicable to Missouri corporations. Dividends are payable by Missouri corporations only under the circumstances specified in The General and Business Corporation Law of Missouri. RGA would not be permitted to pay common stock dividends if there is any accrued and unpaid interest on its subordinated debentures and its junior subordinated debentures. Furthermore, the ability of RGA to pay dividends is dependent on business conditions, income, cash requirements of the Company, receipt of dividends from its subsidiaries, financial covenant provisions and other relevant factors.

Commitments Contingencies and G

Commitments Contingencies and Guarantees	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	COMMITMENTS, CONTINGENCIES AND GUARANTEES Commitments Funding of Investments The Company’s commitments to fund investments as of December 31, 2018 and 2017 are presented in the following table (dollars in thousands): 2018 2017 Limited partnership interests and joint ventures $ 523,903 $ 485,197 Commercial mortgage loans 22,605 40,815 Bank loans and private placements 137,076 60,472 Equity release mortgages 264,858 153,937 The Company anticipates that the majority of its current commitments will be invested over the next five years; however, these commitments could become due any time at the request of the counterparties. Bank loans and private placements are included in fixed maturity securities available-for-sale. Leases The Company leases office space and furniture and equipment under non-cancelable operating lease agreements, which expire at various dates. Future minimum office space annual rentals under non-cancelable operating leases at December 31, 2018 are as follows (dollars in thousands): Operating Leases 2019 $ 13,578 2020 11,541 2021 9,447 2022 8,587 2023 8,248 Thereafter 14,101 Rent expenses amounted to approximately $17.5 million , $15.7 million and $13.7 million for the years ended December 31, 2018, 2017 and 2016 , respectively. Off-Balance Sheet Arrangements In 2013, the Company executed a series of incentive agreements with the County of St. Louis, Missouri (the “County”). Under these agreements, the Company transferred its newly constructed world headquarters to the County in exchange for taxable industrial revenue bonds (the “bonds”), in a series of bond issuances during 2013 and 2014, with a maximum amount of $150.0 million . As a result, the Company was able to reduce the cost of constructing and operating its world headquarters by reducing certain state and local tax expenditures. The Company simultaneously leased the world headquarters from the County and has an option to purchase the world headquarters for a nominal fee upon tendering the bonds back to the County. The payments due to the Company under the terms of the bonds and the amounts owed by the Company under the terms of the lease agreement qualify for the right of offset under GAAP. As such, neither the bonds nor the lease obligation is recorded on the consolidated balance sheets as an asset or liability, respectively. The world headquarters is recorded as an asset of the Company in “Other assets” on the consolidated balance sheets. Contingencies Litigation The Company is subject to litigation in the normal course of its business. The Company currently has no material litigation. A legal reserve is established when the Company is notified of an arbitration demand or litigation or is notified that an arbitration demand or litigation is imminent, it is probable that the Company will incur a loss as a result and the amount of the probable loss is reasonably capable of being estimated. Other Contingencies The Company indemnifies its directors and officers as provided in its charters and by-laws. Since this indemnity generally is not subject to limitation with respect to duration or amount, the Company does not believe that it is possible to determine the maximum potential amount due under this indemnity in the future. Guarantees Statutory Reserve Support RGA, through wholly-owned subsidiaries, has committed to provide statutory reserve support to third-parties, in exchange for a fee, by funding loans if certain defined events occur. Such statutory reserves are required under the U.S. Valuation of Life Policies Model Regulation (commonly referred to as Regulation XXX for term life insurance policies and Regulation A-XXX for universal life secondary guarantees). The third-parties have recourse to RGA should the subsidiary fail to provide the required funding, however, as of December 31, 2018 , the Company does not believe that it will be required to provide any funding under these commitments as the occurrence of the defined events is considered remote. The following table presents the maximum potential obligation for these commitments as of December 31, 2018 (dollars in millions): Commitment Period Maximum Potential Obligation 2023 $ 500.0 2033 450.0 2034 2,000.0 2035 1,314.2 2036 2,658.0 2037 6,750.0 2038 800.0 Other Guarantees RGA has issued guarantees to third parties on behalf of its subsidiaries for the payment of amounts due under certain reinsurance treaties, securities borrowing and repurchase arrangements, financing arrangements and office lease obligations, whereby if a subsidiary fails to meet an obligation, RGA or one of its other subsidiaries will make a payment to fulfill the obligation. In limited circumstances, treaty guarantees are granted to ceding companies in order to provide them additional security, particularly in cases where RGA’s subsidiary is relatively new, unrated, or not of a significant size, relative to the ceding company. Liabilities supported by the treaty guarantees, before consideration for any legally offsetting amounts due from the guaranteed party are reflected on the Company’s consolidated balance sheets in a policy related liability. Potential guaranteed amounts of future payments will vary depending on production levels and underwriting results. Guarantees related to securities borrowing and repurchase arrangements provide additional security to third parties should a subsidiary fail to provide securities when due. RGA’s guarantees issued as of December 31, 2018 and 2017 are reflected in the following table (dollars in thousands): 2018 2017 Treaty guarantees $ 1,392,352 $ 1,047,449 Treaty guarantees, net of assets in trust 1,291,445 926,393 Securities borrowing and repurchase arrangements 269,980 294,325 Financing arrangements 61,273 86,183 Lease obligations 392 1,662

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	DEBT Long-Term Debt The Company’s long-term debt consists of the following as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 $400 million 6.45% Senior Notes due 2019 $ 399,941 $ 399,873 $400 million 5.00% Senior Notes due 2021 399,466 399,245 $400 million 4.70% Senior Notes due 2023 399,288 399,138 $400 million 3.95% Senior Notes due 2026 399,988 399,987 $100 million 4.09% Promissory Note due 2039 89,098 91,787 $400 million 6.20% Subordinated Debentures due 2042 400,000 400,000 $400 million 5.75% Subordinated Debentures due 2056 400,000 400,000 $400 million Variable Rate Junior Subordinated Debentures due 2065 318,743 318,740 Sub-total 2,806,524 2,808,770 Unamortized issuance costs (18,651 ) (20,405 ) Long-term Debt $ 2,787,873 $ 2,788,365 RGA has entered into an interest rate swap on its Variable Rate Junior Subordinated Debentures that effectively fixes the interest rate on these securities at 4.82% until December 2037. Certain of the Company’s debt agreements contain financial covenant restrictions related to, among others, liens, the issuance and disposition of stock of restricted subsidiaries, minimum requirements of consolidated net worth, maximum ratios of debt to capitalization and change of control provisions. A material ongoing covenant default could require immediate payment of the amount due, including principal, under the various agreements. Additionally, the Company’s debt agreements contain cross-default covenants, which would make outstanding borrowings immediately payable in the event of a material uncured covenant default under any of the agreements, including, but not limited to, non-payment of indebtedness when due for an amount in excess of the amounts set forth in those agreements, bankruptcy proceedings, or any other event that results in the acceleration of the maturity of indebtedness. As of December 31, 2018 and 2017 , the Company had $2,806.5 million and $2,808.8 million , respectively, in outstanding borrowings under its debt agreements and was in compliance with all covenants under those agreements. As of December 31, 2018 and 2017 , the average interest rate on long-term debt outstanding was 5.24% . The ability of the Company to make debt principal and interest payments depends on the earnings and surplus of subsidiaries, investment earnings on undeployed capital proceeds, and the Company’s ability to raise additional funds. Future principal payments due on long-term debt, excluding discounts, as of December 31, 2018 , were as follows (dollars in thousands): Calendar Year 2019 2020 2021 2022 2023 Thereafter Long-term debt $ 402,802 $ 2,919 $ 403,040 $ 3,167 $ 403,299 $ 1,593,674 Credit and Committed Facilities The Company has obtained bank letters of credit in favor of various affiliated and unaffiliated insurance companies from which the Company assumes business. These letters of credit represent guarantees of performance under the reinsurance agreements and allow ceding companies to take statutory reserve credits. Certain of these letters of credit contain financial covenant restrictions. At December 31, 2018 and 2017 , there were approximately $105.6 million and $120.1 million , respectively, of undrawn outstanding bank letters of credit in favor of third parties. Additionally, the Company utilizes letters of credit primarily to secure reserve credits when it retrocedes business to its affiliated subsidiaries. The Company cedes business to its affiliates to help reduce the amount of regulatory capital required in certain jurisdictions such as the U.S. and the United Kingdom. As of December 31, 2018 and 2017 , $1,356.9 million and $1,492.2 million , respectively, in undrawn letters of credit from various banks were outstanding, primarily backing reinsurance between the various subsidiaries of the Company. The banks providing letters of credit to the Company are included on the NAIC list of approved banks. The Company maintains eight committed credit facilities, a syndicated revolving credit facility with a capacity of $850.0 million and seven letter of credit facilities with a combined capacity of $1,260.3 million . The Company may borrow cash and obtain letters of credit in multiple currencies under its syndicated revolving credit facility. The following table provides additional information on the Company’s existing committed credit facilities as of December 31, 2018 and 2017 (dollars in thousands): Amount Utilized (1) December 31, Current Capacity Maturity Date 2018 2017 Basis of Fees $191,583 (2) March 2019 $ 4,156 $ 5,952 Fixed 188,000 November 2019 188,000 188,000 Fixed 105,735 (2) December 2019 105,735 117,135 Fixed 100,000 June 2020 — 75,573 Fixed 100,000 May 2021 61,000 100,000 Fixed 75,000 June 2021 33,900 61,900 Fixed 500,000 May 2022 395,000 500,000 Debt rating and utilization % 850,000 August 2023 18,153 95,564 Senior unsecured long-term debt rating (1) Represents issued but undrawn letters of credit. There was no cash borrowed for the periods presented. (2) Foreign currency denominated facility, amounts presented are in U.S. dollars. Fees associated with the Company’s other letters of credit are not fixed for periods in excess of one year and are based on the Company’s ratings and the general availability of these instruments in the marketplace. Total fees expensed associated with the Company’s letters of credit were $9.7 million , $10.5 million and $7.9 million for the years ended December 31, 2018, 2017 and 2016 , respectively, and are included in policy acquisition costs and other insurance expenses.

Collateral Finance and Securiti

Collateral Finance and Securitization Notes	12 Months Ended
	Dec. 31, 2018
Collateralized Financings [Abstract]
Collateral Finance and Securitization Notes	COLLATERAL FINANCE AND SECURITIZATION NOTES Collateral Finance Notes In 2006 , RGA’s subsidiary, Timberlake Financial L.L.C. (“Timberlake Financial”), issued $850.0 million of Series A Floating Rate Insured Notes, due June 2036, in a private placement. The notes were issued to fund the collateral requirements for statutory reserves required by Regulation XXX on specified term life insurance policies reinsured by RGA Reinsurance and retroceded to Timberlake Re. Proceeds from the notes, along with a $112.8 million direct investment by RGA, were deposited into a series of accounts that collateralize the notes and are not available to satisfy the general obligations of the Company. As of December 31, 2018 and 2017 , respectively, the Company held assets in trust and in custody of $767.9 million and $841.5 million , of which $57.1 million and $39.7 million were held in a Debt Service Coverage account to cover interest payments on the notes. Interest on the notes accrues at an annual rate of 1-month LIBOR plus a base rate margin, payable monthly, and totaled $9.4 million , $6.4 million and $4.2 million in 2018, 2017 and 2016 , respectively. In 2015, RGA’s subsidiary, RGA Reinsurance Company (Barbados) Ltd. (“RGA Barbados”) obtained CAD$200.0 million of collateral financing from a third party through 2020, enabling RGA Barbados to support collateral requirements for Canadian reinsurance transactions. The obligation is reflected on the consolidated balance sheets in collateral finance and securitization notes. Interest on the collateral financing is payable quarterly and accrues at 3-month Canadian Dealer Offered Rate plus a margin and totaled $5.1 million , $4.2 million and $4.0 million in 2018, 2017 and 2016 , respectively. In 2015, RGA’s subsidiary, RGA Americas Reinsurance Company, Ltd. (“RGA Americas”), entered into a collateral financing transaction pursuant to which it issued a CAD$150 million note and, in return, obtained a CAD$150 million demand note issued by a designated series of a Delaware master trusts. The demand note matures in October 2020 and is used to support collateral requirements for Canadian reinsurance transactions. The demand note is secured by a portfolio of specified assets that have an aggregate market value at least equal to the principal amount of the demand note and a payment obligation pledged by a third party financial institution. The principal amount of the demand note is payable upon demand by the holder, which creates a corresponding payment under the note issued by RGA Americas. The note issued by RGA Americas bears interest at a rate equal to the rate on the corresponding demand note, plus an amount representing fees payable to the applicable third party financial institution. Through December 31, 2018, no principal payments have been received or are currently due on the demand note and, as a result, there was no payment obligation under the note issued by RGA Americas. Accordingly, the notes are not reflected in the Company’s consolidated balance sheet or the table below, as of that date. Securitization Notes In 2014, RGA’s subsidiary, Chesterfield Financial Holdings LLC, (“Chesterfield Financial”), issued $300.0 million of asset-backed notes due December 2024 in a private placement. The notes were issued as part of an embedded value securitization transaction covering a closed block of policies assumed by RGA Reinsurance and retroceded to Chesterfield Re. Proceeds from the notes, along with a direct investment by the Company, were applied by Chesterfield Financial to (i) pay certain transaction-related expenses, (ii) establish a reserve account owned by Chesterfield Financial and pledged to the indenture trustee for the benefit of the holders of the notes (primarily to cover interest payments on the notes), and (iii) to fund an initial stock purchase from and capital contribution to Chesterfield Re to capitalize Chesterfield Re and to finance the payment of a ceding commission by Chesterfield Re to RGA Reinsurance under the retrocession agreement. As of December 31, 2018 and 2017 , the Company held deposits in trust of $13.5 million and $19.4 million , respectively, to cover interest payments on the notes, which are not available to satisfy the general obligations of the Company. Interest on the notes accrues at an annual rate of 4.50% , payable quarterly, and totaled $9.5 million , $11.3 million and $13.1 million in 2018, 2017 and 2016 , respectively. The notes represent senior, secured indebtedness of Chesterfield Financial. Limited support is provided by RGA for temporary potential liquidity events at Chesterfield Financial and for temporary potential statutory capital and surplus events at Chesterfield Re. Otherwise, there is no legal recourse to RGA or its other subsidiaries. The notes are not insured or guaranteed by any other person or entity. The Company’s collateral finance and securitization notes consist of the following as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Timberlake Financial $ 368,207 $ 411,951 RGA Barbados 131,602 159,100 Chesterfield Financial 185,700 217,800 Unamortized issuance costs (3,548 ) (4,913 ) Total $ 681,961 $ 783,938

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION The Company has geographic-based and business-based operational segments. Geographic-based operations are further segmented into traditional and financial solutions businesses. The U.S. and Latin America Traditional segment provides individual and group life and health reinsurance to domestic clients for a variety of products through yearly renewable term agreements, coinsurance, and modified coinsurance. The U.S. and Latin America Financial Solutions segment includes asset-intensive products that concentrate on the investment risk within underlying annuities and corporate-owned life insurance policies, and financial reinsurance that assists ceding companies in meeting applicable regulatory requirements while enhancing their financial strength and regulatory surplus position. The Canada Traditional segment is primarily engaged in individual life reinsurance, and to a lesser extent creditor, group life and health, critical illness and disability reinsurance, through yearly renewable term and coinsurance agreements. The Canada Financial Solutions segment concentrates on assisting clients with longevity risk transfer structures within underlying annuities and pension benefit obligations, and on assisting clients in meeting applicable regulatory requirements while enhancing their financial strength and regulatory surplus position through financial reinsurance structures. The Europe, Middle East and Africa Traditional segment provides individual and group life and health products through yearly renewable term and coinsurance agreements, reinsurance of critical illness coverage that provides a benefit in the event of the diagnosis of a pre-defined critical illness and underwritten annuities. The Europe, Middle East and Africa Financial Solutions segment provides longevity, asset-intensive and financial reinsurance. Longevity reinsurance takes the form of closed block annuity reinsurance and longevity swap structures. The Asia Pacific Traditional segment provides individual and group life and health reinsurance, critical illness coverage, disability and superannuation through yearly renewable term and coinsurance agreements. The Asia Pacific Financial Solutions segment provides financial reinsurance, asset-intensive and certain disability and life blocks. Corporate and Other revenues primarily include investment income from unallocated invested assets, investment related gains and losses and service fees. Corporate and Other expenses consist of the offset to capital charges allocated to the operating segments within the policy acquisition costs and other insurance income line item, unallocated overhead and executive costs, interest expense related to debt, and the investment income and expense associated with the Company’s collateral finance and securitization transactions and service business expenses. Additionally, Corporate and Other includes results from certain wholly-owned subsidiaries, such as RGAx, and joint ventures that, among other activities, develop and market technology, and provide consulting and outsourcing solutions for the insurance and reinsurance industries. In the past two years, the Company has increased its investment and expenditures in this area in an effort to both support its clients and generate new future revenue streams. The accounting policies of the segments are the same as those described in Note 2 – “Significant Accounting Policies and Pronouncements.” The Company measures segment performance primarily based on profit or loss from operations before income taxes. There are no intersegment reinsurance transactions and the Company does not have any material long-lived assets. The Company allocates capital to its segments based on an internally developed economic capital model, the purpose of which is to measure the risk in the business and to provide a basis upon which capital is deployed. The economic capital model considers the unique and specific nature of the risks inherent in the Company’s businesses. As a result of the economic capital allocation process, a portion of investment income is attributed to the segments based on the level of allocated capital. In addition, the segments are charged for excess capital utilized above the allocated economic capital basis. This charge is included in policy acquisition costs and other insurance expenses. Information related to revenues, income (loss) before income taxes, interest expense, depreciation and amortization, and assets of the Company’s operations are summarized below (dollars in thousands): For the years ended December 31, 2018 2017 2016 Revenues: U.S. and Latin America: Traditional $ 6,295,733 $ 6,100,171 $ 5,964,968 Financial Solutions 907,245 1,150,378 840,446 Total 7,202,978 7,250,549 6,805,414 Canada: Traditional 1,224,404 1,103,520 1,118,004 Financial Solutions 48,588 48,938 46,938 Total 1,272,992 1,152,458 1,164,942 Europe, Middle East and Africa: Traditional 1,494,605 1,362,075 1,195,149 Financial Solutions 349,886 311,071 340,518 Total 1,844,491 1,673,146 1,535,667 Asia Pacific: Traditional 2,416,848 2,210,686 1,771,150 Financial Solutions 54,479 73,775 63,382 Total 2,471,327 2,284,461 1,834,532 Corporate and Other 83,876 155,155 180,956 Total $ 12,875,664 $ 12,515,769 $ 11,521,511 For the years ended December 31, 2018 2017 2016 Income (loss) before income taxes: U.S. and Latin America: Traditional $ 286,410 $ 373,434 $ 371,101 Financial Solutions 250,478 401,584 283,380 Total 536,888 775,018 654,481 Canada: Traditional 112,308 120,218 134,705 Financial Solutions 9,576 16,643 7,945 Total 121,884 136,861 142,650 Europe, Middle East and Africa: Traditional 55,119 70,486 30,059 Financial Solutions 196,387 123,514 138,007 Total 251,506 194,000 168,066 Asia Pacific: Traditional 177,501 148,786 113,928 Financial Solutions (5,966 ) 13,130 4,063 Total 171,535 161,916 117,991 Corporate and Other (235,993 ) (124,980 ) (39,242 ) Total $ 845,820 $ 1,142,815 $ 1,043,946 For the years ended December 31, 2018 2017 2016 Interest expense: Corporate and Other $ 147,355 $ 146,025 $ 137,623 Total $ 147,355 $ 146,025 $ 137,623 For the years ended December 31, 2018 2017 2016 Depreciation and amortization: U.S. and Latin America: Traditional $ 272,555 $ 284,959 $ 271,732 Financial Solutions 95,306 208,790 155,560 Total 367,861 493,749 427,292 Canada: Traditional 22,109 24,057 22,170 Financial Solutions 9 10 11 Total 22,118 24,067 22,181 Europe, Middle East and Africa: Traditional 45,140 35,000 46,562 Financial Solutions 384 91 72 Total 45,524 35,091 46,634 Asia Pacific: Traditional 114,870 114,333 45,562 Financial Solutions 1,885 1,448 1,492 Total 116,755 115,781 47,054 Corporate and Other 22,104 37,276 13,894 Total $ 574,362 $ 705,964 $ 557,055 The table above includes amortization of DAC, including the effect from investment related gains and losses. For the years ended December 31, 2018 2017 Assets: U.S. and Latin America: Traditional $ 19,235,781 $ 18,603,423 Financial Solutions 19,870,388 15,959,206 Total 39,106,169 34,562,629 Canada: Traditional 4,200,792 4,161,452 Financial Solutions 154,000 126,372 Total 4,354,792 4,287,824 Europe, Middle East and Africa: Traditional 3,643,174 3,099,495 Financial Solutions 4,737,529 5,274,993 Total 8,380,703 8,374,488 Asia Pacific: Traditional 5,680,978 4,915,442 Financial Solutions 1,180,745 1,198,585 Total 6,861,723 6,114,027 Corporate and Other 5,831,858 7,175,850 Total $ 64,535,245 $ 60,514,818 Companies in which RGA has significant influence over the operating and financing decisions but are not required to be consolidated, are reported on the equity basis of accounting. The equity in the net income of such investments is not material to the results of operations or financial position of individual segments or the Company taken as a whole. Capital expenditures of each reporting segment were immaterial in the periods noted. No individual client generated 10% or more of the Company’s total gross premiums on a consolidated basis in 2018, 2017 and 2016 . For the purpose of this disclosure, companies that are within the same insurance holding company structure are combined.

Policy Claims and Benefits

Policy Claims and Benefits	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Short-Duration Insurance and Deposit Contracts [Text Block]	Liabilities for Unpaid Claims and Claim Expense The Company uses several actuarial methods to compute incurred-but-not reported liabilities. These methods use historical claim reporting patterns to develop a triangle of reported claim amounts. The claim triangle is then used to develop the ultimate claims amount and the incurred-but-not reported liabilities. Expected claim methods use exposure data such as premiums to develop the ultimate claim amount. The final method blends the estimates from the development and the expected claim methods. There were no significant changes in methodologies during 2018. The following tables provide information on incurred and paid claims development, net of retrocession, for short-duration reinsurance contracts for the Company’s U.S. and Latin America and Asia Pacific Traditional segments, which primarily relate to group life and health (including disability) business. The short-duration business for the Company’s other segments is immaterial. Liabilities for claims and claims adjustment expenses, net of reinsurance equals total incurred claims less cumulative paid claims plus outstanding liabilities prior to 2012. The Company provides reinsurance on large quota share transactions. It is common industry practice for cedants to provide loss information on a bulk basis without comprehensive claim details. Additionally, a claim under aggregate stop loss coverage may be the result of thousands of claims, but the Company only pays the excess amount. Therefore, it is impractical to provide meaningful claim count detail by accident year in the tables shown below. U.S. and Latin America As of (in thousands) December 31, 2018 Incurred Claims and Allocated Claim Adjustments, Net of Reinsurance (1) Total of Incurred-but-Not-Reported Liabilities Plus Expected Development on Reported Claims Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 322,579 $ 309,119 $ 297,037 $ 298,262 $ 299,098 $ 297,688 $ 296,717 $ — 2013 349,262 332,907 338,977 336,552 336,436 336,323 24 2014 407,953 411,373 396,383 397,151 396,010 272 2015 459,524 460,917 465,167 461,947 1,505 2016 500,843 499,785 500,725 4,885 2017 485,442 513,722 27,190 2018 538,456 234,548 Total $ 3,043,900 Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net of Reinsurance (1) Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 109,323 $ 222,139 $ 243,890 $ 252,018 $ 258,297 $ 263,565 $ 268,073 2013 114,457 248,828 277,130 285,817 292,067 297,126 2014 128,813 304,578 337,081 349,078 356,026 2015 146,196 360,658 407,282 422,102 2016 184,940 392,517 436,892 2017 189,853 402,759 2018 182,560 Total $ 2,365,538 All outstanding claims prior to 2012, net of reinsurance 178,024 Liabilities for claims and claim adjustment expense, net of reinsurance $ 856,386 (1) 2012-2017 Unaudited. Asia Pacific As of (in thousands) December 31, 2018 Incurred Claims and Allocated Claim Adjustments, Net of Reinsurance (1) Total of Incurred-but-Not-Reported Liabilities Plus Expected Development on Reported Claims Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 207,882 $ 279,008 $ 283,316 $ 286,632 $ 294,265 $ 303,340 $ 309,287 $ 10,352 2013 292,769 313,126 303,779 301,168 314,283 328,017 16,728 2014 277,049 300,336 265,431 272,247 284,237 21,339 2015 278,491 257,146 251,650 267,292 32,392 2016 227,653 211,425 212,722 40,376 2017 216,499 214,707 63,383 2018 253,691 156,761 Total $ 1,869,953 Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net of Reinsurance (1) Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 49,321 $ 135,322 $ 185,322 $ 222,987 $ 243,549 $ 259,917 $ 274,830 2013 49,805 144,247 209,347 235,923 261,299 282,961 2014 34,519 135,668 177,439 206,176 228,873 2015 48,962 118,579 167,350 202,273 2016 38,310 97,769 133,091 2017 35,442 87,037 2018 31,871 Total $ 1,240,936 All outstanding claims prior to 2012, net of reinsurance 112,373 Liabilities for claims and claim adjustment expense, net of reinsurance $ 741,390 (1) 2012-2017 Unaudited. The following is unaudited supplementary information about average historical claims duration as of December 31, 2018 : Average Annual Payout of Incurred Claims by Age, Net of Reinsurance Years 1 2 3 4 5 6 7 U.S. and Latin America 34.7 % 41.9 % 8.6 % 2.9 % 1.9 % 1.6 % 1.5 % Asia Pacific 15.5 % 28.4 % 17.1 % 10.9 % 7.5 % 5.9 % 4.8 % Reconciliation of the Disclosure of Incurred and Paid Claims Development to the Liability for Unpaid Claims and Claims Adjustment Expenses The reconciliation of the net incurred and paid claims development tables to the liability for claims and claim adjustment expense in the consolidated balance sheet as of December 31, 2018 is as follows (dollars in thousands): 2018 Liabilities for claims and claim adjustment expense, net of reinsurance: U.S. and Latin America $ 856,386 Asia Pacific 741,390 Liabilities for claims and claim adjustment expense, net of reinsurance 1,597,776 Adjustments to reconcile to total policy claims and future policy benefits: Reinsurance recoverable 16,121 Effect of discounting (141,689 ) Unallocated claims adjustment expense 5,907 Total adjustments (119,661 ) Other short-duration contracts: Canada 128,831 Europe, Middle East and Africa 383,936 Other 177,416 Liability for unpaid claims and claim adjustment expense - short-duration 2,168,298 Liability for unpaid claims and claim adjustment expense - long-duration 4,416,370 Total liability for unpaid claims and claim adjustment expense (included in future policy benefits and other policy-related balances) $ 6,584,668 Rollforward of Claims and Claim Adjustment Expenses The liability for unpaid claims is reported in future policy benefits and other policy-related balances within the Company’s consolidated balance sheet. Activity associated with unpaid claims is summarized below (dollars in thousands): 2018 2017 2016 Balance at beginning of year $ 5,896,469 $ 5,180,802 $ 4,977,836 Less: reinsurance recoverable (455,547 ) (394,821 ) (405,583 ) Net balance at beginning of year 5,440,922 4,785,981 4,572,253 Incurred: Current year 10,048,866 8,911,640 8,562,036 Prior years 131,181 14,364 (134,765 ) Total incurred 10,180,047 8,926,004 8,427,271 Payments: Current year (4,602,535 ) (4,513,606 ) (4,385,839 ) Prior years (4,691,722 ) (4,004,038 ) (3,777,137 ) Total payments (9,294,257 ) (8,517,644 ) (8,162,976 ) Other changes: Interest accretion 24,802 19,443 18,151 Foreign exchange adjustments (199,428 ) 227,138 (68,718 ) Total other changes (174,626 ) 246,581 (50,567 ) Net balance at end of year 6,152,086 5,440,922 4,785,981 Plus: reinsurance recoverable 432,582 455,547 394,821 Balance at end of year $ 6,584,668 $ 5,896,469 $ 5,180,802 Incurred claims related to prior years reflected in the table above, resulted in part from developed claims for prior years being different than were anticipated when the liabilities for unpaid claims were originally estimated. These trends have been considered in establishing the current year liability for unpaid claims.

Equity

Equity	12 Months Ended
	Dec. 31, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income	EQUITY Common stock The changes in number of common stock shares, issued, held in treasury and outstanding are as follows for the periods indicated: Issued Held In Treasury Outstanding Balance, December 31, 2015 79,137,758 13,933,232 65,204,526 Common Stock acquired — 1,356,892 (1,356,892 ) Stock-based compensation (1) — (454,868 ) 454,868 Balance, December 31, 2016 79,137,758 14,835,256 64,302,502 Common Stock acquired — 208,680 (208,680 ) Stock-based compensation (1) — (358,273 ) 358,273 Balance, December 31, 2017 79,137,758 14,685,663 64,452,095 Common Stock acquired — 1,932,055 (1,932,055 ) Stock-based compensation (1) — (294,328 ) 294,328 Balance, December 31, 2018 79,137,758 16,323,390 62,814,368 (1) Represents net shares issued from treasury pursuant to the Company’s stock-based compensation programs. Common stock held in treasury Common stock held in treasury is accounted for at average cost. Gains resulting from the reissuance of “Common stock held in treasury” are credited to “Additional paid-in capital.” Losses resulting from the reissuance of “Common stock held in treasury” are charged first to “Additional paid-in capital” to the extent the Company has previously recorded gains on treasury share transactions, then to “Retained earnings.” During 2017, RGA’s board of directors authorized and amended a share repurchase program, with no expiration date, to repurchase up to $400.0 million of RGA’s outstanding common stock. In connection with this authorization, the board of directors terminated all previously announced repurchase authorizations. The following table summarizes the Company’s current share repurchase program activity for the years ended 2018 and 2017 (dollar amounts in thousands, except per share amounts): Year of Repurchase Shares Repurchased Amount Paid Average Per Share 2018 1,932,055 $ 283,524 $ 146.75 2017 208,680 26,897 $ 128.89 Total 2,140,735 $ 310,421 During 2016, RGA’s board of directors authorized and amended a share repurchase program, with no expiration date, to repurchase up to $400.0 million of RGA’s outstanding common stock. During 2016, RGA repurchased 1,356,892 shares of common stock under this program for $116.5 million . On January 24, 2019, RGA’s board of directors authorized a share repurchase program for up to $400.0 million of RGA’s outstanding common stock. The authorization was effective immediately and does not have an expiration date. In connection with this new authorization, the board of directors terminated the stock repurchase authority granted in 2017. The timing and amount of share repurchases are determined by management based upon market conditions and other considerations. Factors could affecting the timing and amount of any future repurchases under the share repurchase authorization, include increased capital needs of the Company due to changes in regulatory capital requirements, opportunities for growth and acquisitions, and the effect of adverse market conditions on the segments. Accumulated other comprehensive income (loss) The following table presents the components of the Company’s other comprehensive income (loss) for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): For the year ended December 31, 2018 : Before-Tax Amount Tax (Expense) Benefit After-Tax Amount Foreign currency translation adjustments: Change arising during year $ (148,018 ) $ (759 ) $ (148,777 ) Foreign currency swap 87,344 (18,342 ) 69,002 Net foreign currency translation adjustments (60,674 ) (19,101 ) (79,775 ) Unrealized gains on investments: (1) Unrealized net holding gains arising during the year (1,834,656 ) 393,653 (1,441,003 ) Less: Reclassification adjustment for net gains realized in net income (122,221 ) 25,720 (96,501 ) Net unrealized gains (1,712,435 ) 367,933 (1,344,502 ) Unrealized pension and postretirement benefits: Net prior service cost arising during the year (947 ) 182 (765 ) Net gain arising during the period 1,063 (316 ) 747 Unrealized pension and postretirement benefits, net 116 (134 ) (18 ) Other comprehensive income (loss) $ (1,772,993 ) $ 348,698 $ (1,424,295 ) For the year ended December 31, 2017 : Before-Tax Amount Tax (Expense) Benefit After-Tax Amount Foreign currency translation adjustments: Change arising during year $ 74,926 $ 25,369 $ 100,295 Foreign currency swap (47,953 ) 16,784 (31,169 ) Net foreign currency translation adjustments 26,973 42,153 69,126 Unrealized gains on investments: (1) Unrealized net holding gains arising during the year 1,029,591 (313,729 ) 715,862 Less: Reclassification adjustment for net gains realized in net income 25,039 (7,011 ) 18,028 Net unrealized gains 1,004,552 (306,718 ) 697,834 Change in unrealized OTTI on fixed maturity securities 375 (131 ) 244 Unrealized pension and postretirement benefits: Net prior service cost arising during the year 11,717 (4,095 ) 7,622 Net gain arising during the period (10,587 ) 3,691 (6,896 ) Unrealized pension and postretirement benefits, net 1,130 (404 ) 726 Other comprehensive income (loss) $ 1,033,030 $ (265,100 ) $ 767,930 For the year ended December 31, 2016 : Before-Tax Amount Tax (Expense) Benefit After-Tax Amount Foreign currency translation adjustments: Change arising during year $ 39,925 $ (24,663 ) $ 15,262 Foreign currency swap (10,234 ) 3,582 (6,652 ) Net foreign currency translation adjustments 29,691 (21,081 ) 8,610 Unrealized gains on investments: (1) Unrealized net holding gains arising during the year 641,606 (180,448 ) 461,158 Less: Reclassification adjustment for net gains realized in net income 65,798 (23,029 ) 42,769 Net unrealized gains 575,808 (157,419 ) 418,389 Change in unrealized OTTI on fixed maturity securities 1,457 (510 ) 947 Unrealized pension and postretirement benefits: Net prior service cost arising during the year 444 (149 ) 295 Net gain arising during the period 4,427 (1,623 ) 2,804 Unrealized pension and postretirement benefits, net 4,871 (1,772 ) 3,099 Other comprehensive income (loss) $ 611,827 $ (180,782 ) $ 431,045 (1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges. A summary of the components of net unrealized appreciation (depreciation) of balances carried at fair value is as follows (dollars in thousands): For the years ended December 31, 2018 2017 2016 Change in net unrealized appreciation (depreciation) on: Fixed maturity securities available-for-sale $ (1,759,230 ) $ 987,570 $ 561,906 Other investments (1) 20,187 25,577 18,900 Effect on unrealized appreciation on: Deferred policy acquisition costs 26,608 (8,220 ) (3,541 ) Net unrealized appreciation (depreciation) $ (1,712,435 ) $ 1,004,927 $ 577,265 (1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges. The balance of and changes in each component of AOCI were as follows (dollars in thousands): Accumulated Currency Translation Adjustments Unrealized Appreciation (Depreciation) of Investments (1) Pension and Postretirement Benefits Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2015 $ (181,151 ) $ 935,697 $ (46,262 ) $ 708,284 OCI before reclassifications 29,691 646,887 (951 ) 675,627 Amounts reclassified from AOCI — (69,622 ) 5,822 (63,800 ) Deferred income tax benefit (expense) (21,081 ) (157,929 ) (1,772 ) (180,782 ) Balance, December 31, 2016 (172,541 ) 1,355,033 (43,163 ) 1,139,329 OCI before reclassifications 26,973 1,039,387 (4,273 ) 1,062,087 Amounts reclassified from AOCI — (34,460 ) 5,403 (29,057 ) Deferred income tax benefit (expense) 42,153 (306,849 ) (404 ) (265,100 ) Adoption of new accounting standard 17,065 147,550 (8,243 ) 156,372 Balance, December 31, 2017 (86,350 ) 2,200,661 (50,680 ) 2,063,631 OCI before reclassifications (60,674 ) (1,860,789 ) (5,218 ) (1,926,681 ) Amounts reclassified from AOCI — 148,354 5,334 153,688 Deferred income tax benefit (expense) (19,101 ) 367,933 (134 ) 348,698 Adoption of new accounting standard (2,573 ) — — (2,573 ) Balance, December 31, 2018 $ (168,698 ) $ 856,159 $ (50,698 ) $ 636,763 (1) Includes cash flow hedges of $8,788 , $2,619 and $(2,496) as of December 31, 2018, 2017 and 2016 , respectively. See Note 5 for additional information on cash flow hedges. The following table presents the amounts of AOCI reclassifications for the years ended December 31, 2018 and 2017 (dollars in thousands): Amount Reclassified from AOCI Details about AOCI Components 2018 2017 Affected Line Item in Statement of Income Net unrealized investment gains (losses): Net unrealized gains and losses on available-for-sale securities $ (122,221 ) $ 25,039 Investment related gains (losses), net Cash flow hedges - Interest rate 183 (79 ) (1) Cash flow hedges - Currency/Interest rate 292 380 (1) Cash flow hedges - Forward bond purchase commitments — 900 (1) Deferred policy acquisition costs attributed to unrealized gains and losses (26,608 ) 8,220 (2) Total (148,354 ) 34,460 Provision for income taxes 31,208 (10,308 ) Net unrealized gains (losses), net of tax $ (117,146 ) $ 24,152 Amortization of defined benefit plan items: Prior service cost (credit) $ 971 $ 971 (3) Actuarial gains/(losses) (6,305 ) (6,374 ) (3) Total (5,334 ) (5,403 ) Provision for income taxes 1,176 1,891 Amortization of defined benefit plans, net of tax $ (4,158 ) $ (3,512 ) Total reclassifications for the period $ (121,304 ) $ 20,640 (1) See Note 5 for information on cash flow hedges. (2) See Note 8 for information on deferred policy acquisition costs. (3) See Note 10 for information on employee benefit plans.

Equity Based Compensation

Equity Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Based Compensation	Equity Based Compensation The Company adopted the RGA Flexible Stock Plan (the “Plan”) in February 1993, as amended, and the Flexible Stock Plan for Directors (the “Directors Plan”) in January 1997, as amended, (collectively, the “Stock Plans”). The Stock Plans provide for the award of benefits (collectively “Benefits”) of various types, including stock options, stock appreciation rights (“SARs”), restricted stock, performance shares, cash awards, and other stock-based awards, to key employees, officers, directors and others performing significant services for the benefit of the Company or its subsidiaries. As of December 31, 2018 , shares authorized for the granting of Benefits under the Plan and the Directors Plan totaled 14,960,077 and 412,500 respectively. The Company uses treasury shares or shares made available from authorized but unissued shares to support the future exercise of options or settlement of awards granted under its stock plans. Equity-based compensation expense of $30.1 million , $22.3 million , and $33.1 million related to grants or awards under the Stock Plans was recognized in 2018, 2017 and 2016 , respectively. Equity-based compensation expense is principally related to the issuance of stock options, performance contingent restricted units, stock appreciation rights and restricted stock. In general, options granted under the Plan become exercisable over vesting periods ranging from one to five years. Options are generally granted with an exercise price equal to the stock’s fair value at the date of grant and expire 10 years after the date of grant. There are no options outstanding under the Directors Plan during the periods presented. Information with respect to grants under the Stock Plans follows. Stock Options The following table presents a summary of stock option activity: Number of Options Weighted-Average Exercise Price Aggregate Intrinsic Value (in millions) Outstanding December 31, 2017 2,309,769 $ 75.17 Granted 164,889 $ 150.87 Exercised (286,874 ) $ 59.45 Forfeited (17,341 ) $ 119.63 Outstanding December 31, 2018 2,170,443 $ 82.65 $ 126.7 Options exercisable 1,633,182 $ 73.09 $ 110.1 The intrinsic value of options exercised was $25.6 million , $42.1 million , and $41.4 million for 2018, 2017 and 2016 , respectively. Options Outstanding Options Exercisable Range of Exercise Prices Number Outstanding as of 12/31/2018 Weighted-Average Remaining Contractual Life (years) Weighted- Average Exercise Price Number Exercisable as of 12/31/2018 Weighted-Average Exercise Price $0.00 - $49.99 163,805 0.9 $ 43.97 163,805 $ 43.97 $50.00 - $59.99 775,518 3.5 $ 58.26 775,518 $ 58.26 $60.00 - $69.99 839 4.2 $ 60.24 839 $ 60.24 $70.00 - $79.99 159,593 5.2 $ 78.48 159,593 $ 78.48 $90.00 + 1,070,688 7.4 $ 106.87 533,427 $ 102.00 Totals 2,170,443 5.3 $ 82.65 1,633,182 $ 73.09 The following table presents the weighted average assumptions used to determine the fair value of stock options issued: For the years ended December 31, 2018 2017 2016 Dividend yield 1.33 % 1.26 % 1.58 % Risk-free rate of return 2.79 % 2.32 % 1.69 % Expected volatility 21.4 % 22.8 % 28.1 % Expected life (years) 7.0 7.0 7.0 Weighted average exercise price of stock options granted $ 150.87 $ 129.72 $ 93.53 Weighted average fair value of stock options granted $ 36.31 $ 31.57 $ 24.52 The Black-Scholes model was used to determine the fair value recognized in the financial statements of stock options that have been granted. The Company used daily historical volatility when calculating stock option values. The benchmark rate is based on observed interest rates for instruments with maturities similar to the expected term of the stock options. Dividend yield is determined based on historical dividend distributions compared to the price of the underlying common stock as of the valuation date and held constant over the life of the stock options. The Company estimated expected life using the historical average years to exercise or cancellation. Performance Shares Performance shares, also referred to as performance contingent units (“PCUs”), are units that, if they vest, are multiplied by a performance factor to produce a number of final PCUs that are paid in the Company’s common stock. Each PCU represents the right to receive up to two shares of Company common stock, depending on the results of certain performance measures over a three -year period. The compensation expense related to the PCUs is recognized ratably over the requisite performance period. Performance shares are accounted for as equity awards, but are not credited with dividend-equivalents for actual dividends paid on the Company’s common stock during the performance period. Restricted Stock Units In general, restricted stock units (“RSUs”) become payable at the end of a three- or ten-year vesting period. Each RSU, if they vest, represents the right to receive one share of Company common stock. RSUs awarded under the plan generally have no strike price and are included in the Company’s shares outstanding. The following table presents a summary of Performance Share and Restricted Stock Unit activity: Performance Contingent Units Restricted Stock Units Outstanding December 31, 2017 463,259 77,358 Granted 110,042 20,393 Paid (170,080 ) (28,023 ) Forfeited (7,350 ) (2,729 ) Outstanding December 31, 2018 395,871 66,999 During 2018, the Company issued 110,042 PCUs to key employees at a weighted average fair value per unit of $150.87 . In May 2018 and May 2017, RGA’s board of directors approved a 1.07 and 0.75 share payout for each PCU granted in 2016 and 2015, resulting in the issuance of 170,080 and 137,083 shares of common stock from treasury, respectively. As of December 31, 2018 , the total compensation cost of non-vested awards not yet recognized in the financial statements was $24.7 million . It is estimated that these costs will vest over a weighted average period of 1.4 years. The majority of the awards granted each year under the board-approved incentive compensation package and Directors Plan are made in the first quarter of each year.

Quarterly Results of Operations

Quarterly Results of Operations	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) Years Ended December 31, (in thousands, except per share data) 2018 First Second Third Fourth Total Revenues $ 3,173,707 $ 3,195,908 $ 3,227,531 $ 3,278,518 Total benefits and expenses 3,035,782 2,948,620 2,904,870 3,140,572 Income before income taxes 137,925 247,288 322,661 137,946 Net Income 100,230 204,374 301,199 110,039 Earnings Per Share: Basic earnings per share $ 1.55 $ 3.19 $ 4.76 $ 1.75 Diluted earnings per share 1.52 3.13 4.68 1.72 2017 First Second Third Fourth Total Revenues $ 3,008,740 $ 3,129,276 $ 3,145,310 $ 3,232,443 Total benefits and expenses 2,800,896 2,789,961 2,805,148 2,976,949 Income before income taxes 207,844 339,315 340,162 255,494 Net Income 145,512 232,190 227,591 1,216,888 Earnings Per Share: Basic earnings per share $ 2.26 $ 3.60 $ 3.53 $ 18.89 Diluted earnings per share 2.22 3.54 3.47 18.49

Subsequent Event (Notes)

Subsequent Event (Notes)	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	SUBSEQUENT EVENT On January 24, 2019, RGA’s board of directors authorized a share repurchase program for up to $400.0 million of RGA’s outstanding common stock. The authorization was effective immediately and does not have an expiration date. Repurchases would be made in accordance with applicable securities laws and would be made through market transactions, block trades, privately negotiated transactions or other means or a combination of these methods, with the timing and number of shares repurchased dependent on a variety of factors, including share price, corporate and regulatory requirements and market and business conditions. Repurchases may be commenced or suspended from time to time without prior notice. In connection with this new authorization, the board of directors terminated the stock repurchase authority granted in 2017.

Summary of Investments Other Th

Summary of Investments Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Summary of Investments Other Than Investments in Related Parties	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE I-SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES December 31, 2018 (in millions) Type of Investment Amortized Cost Estimated Fair Value Amount at Which Shown in the Balance Sheets (1) Fixed maturity securities: United States government and government agencies and authorities $ 2,234 $ 2,186 $ 2,186 State and political subdivisions 721 752 752 Foreign governments (2) 6,449 7,635 7,635 Public utilities 2,876 2,909 2,909 Mortgage-backed and asset-backed securities 5,472 5,437 5,437 All other corporate bonds 21,130 21,073 21,073 Total fixed maturity securities $ 38,882 $ 39,992 $ 39,992 Equity securities $ 108 $ 82 $ 82 Mortgage loans on real estate 4,966 4,966 Policy loans 1,345 1,345 Funds withheld at interest 5,762 5,762 Short-term investments 143 143 Other invested assets 1,915 1,915 Total investments $ 53,121 $ 54,205 (1) Fixed maturity securities are classified as available-for-sale and carried at fair value. (2) Includes fixed maturities directly issued by foreign governments, supranational and foreign government-sponsored enterprises.

Condensed Financial Information

Condensed Financial Information of The Registrant	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of The Registrant	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE II—CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT December 31, (in thousands) 2018 2017 2016 CONDENSED BALANCE SHEETS Assets: Fixed maturity securities available-for-sale, at fair value $ 595,303 $ 710,303 Short-term and other investments 42,906 54,517 Cash and cash equivalents 20,641 15,176 Investment in subsidiaries 11,033,195 12,043,911 Loans to subsidiaries 1,010,000 1,010,000 Other assets 239,643 234,707 Total assets $ 12,941,688 $ 14,068,614 Liabilities and stockholders’ equity: Long-term debt - unaffiliated (1) $ 2,777,756 $ 2,775,579 Long-term debt - affiliated (2) 500,000 500,000 Other liabilities 1,213,379 1,223,500 Stockholders’ equity 8,450,553 9,569,535 Total liabilities and stockholders’ equity $ 12,941,688 $ 14,068,614 CONDENSED STATEMENTS OF INCOME Interest / dividend income (3) $ 575,833 $ 131,067 $ 602,830 Investment related gains (losses), net (5,392 ) (5,187 ) 203 Operating expenses (35,912 ) (20,517 ) (20,742 ) Interest expense (181,364 ) (177,417 ) (168,924 ) Income (loss) before income tax and undistributed earnings of subsidiaries 353,165 (72,054 ) 413,367 Income tax expense (benefit) (37,294 ) 65,882 (23,911 ) Net income (loss) before undistributed earnings of subsidiaries 390,459 (137,936 ) 437,278 Equity in undistributed earnings of subsidiaries 325,383 1,960,117 264,165 Net income 715,842 1,822,181 701,443 Other comprehensive income (loss) 21,455 (7,672 ) 5,531 Total comprehensive income $ 737,297 $ 1,814,509 $ 706,974 The condensed financial information of RGA (the “Parent Company”) should be read in conjunction with the consolidated financial statements of RGA and its subsidiaries and the notes thereto (the “Consolidated Financial Statements”). These condensed unconsolidated financial statements reflect the results of operations, financial position and cash flows for RGA. Investments in subsidiaries are accounted for using the equity method of accounting. (1) Long-term debt - unaffiliated consists of the following: 2018 2017 $400 million 6.45% Senior Notes due 2019 $ 399,941 $ 399,873 $400 million 5.00% Senior Notes due 2021 399,466 399,245 $400 million 4.70% Senior Notes due 2023 399,289 399,138 $400 million 3.95% Senior Notes due 2026 399,987 399,987 $400 million 6.20% Subordinated Debentures due 2042 400,000 400,000 $400 million 5.75% Subordinated Debentures due 2056 400,000 400,000 $400 million Variable Rate Junior Subordinated Debentures due 2065 398,674 398,670 Subtotal 2,797,357 2,796,913 Unamortized debt issue costs (19,601 ) (21,334 ) Total $ 2,777,756 $ 2,775,579 Repayments of long-term debt—unaffiliated due over the next five years total $400,000 in 2019, $400,000 in 2021 and $400,000 in 2023. (2) Long-term debt—affiliated in 2018 and 2017 and consists of $500,000 of subordinated debt issued to various operating subsidiaries. (3) Interest/dividend income includes $450,000 and $478,602 of cash dividends received from consolidated subsidiaries in 2018 and 2016, respectively. In 2017 there were no cash dividends received from consolidated subsidiaries. REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE II—CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT (continued) December 31, (in thousands) 2018 2017 2016 CONDENSED STATEMENTS OF CASH FLOWS Operating activities: Net income $ 715,842 $ 1,822,181 $ 701,443 Equity in earnings of subsidiaries (325,383 ) (1,960,117 ) (264,165 ) Other, net 36,754 57,677 (63,795 ) Net cash (used in) provided by operating activities 427,213 (80,259 ) 373,483 Investing activities: Sales of fixed maturity securities available-for-sale 482,324 514,508 228,383 Purchases of fixed maturity securities available-for-sale (383,392 ) (75,000 ) (984,397 ) Repayments/issuances of loans to subsidiaries — 40,000 20,000 Change in short-term investments — — 102,508 Change in other invested assets 44 125,506 (109,914 ) Capital contributions to subsidiaries (82,150 ) (62,500 ) (314,142 ) Net cash (used in) provided by investing activities 16,826 542,514 (1,057,562 ) Financing activities: Dividends to stockholders (140,110 ) (117,291 ) (100,371 ) Purchases of treasury stock (299,679 ) (43,508 ) (122,916 ) Exercise of stock options, net 3,459 7,292 15,321 Net change in cash collateral for loaned securities (2,244 ) (37,290 ) 105,093 Principal payments on debt — (300,000 ) — Proceeds from unaffiliated long-term debt issuance — — 799,984 Debt issuance costs — — (8,766 ) Net cash (used in) provided by financing activities (438,574 ) (490,797 ) 688,345 Net change in cash and cash equivalents 5,465 (28,542 ) 4,266 Cash and cash equivalents at beginning of year 15,176 43,718 39,452 Cash and cash equivalents at end of year $ 20,641 $ 15,176 $ 43,718 Supplementary information: Cash paid for interest $ 176,236 $ 185,554 $ 169,860 Cash paid for income taxes, net of refunds $ 93,000 $ 8,248 $ 1,500

Supplementary Insurance Informa

Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Supplementary Insurance Information	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE III—SUPPLEMENTARY INSURANCE INFORMATION (in thousands) As of December 31, Deferred Policy Acquisition Costs Future Policy Benefits and Interest-Sensitive Contract Liabilities Other Policy Claims and Benefits Payable 2018 U.S. and Latin America: Traditional $ 1,824,874 $ 11,727,505 $ 1,948,335 Financial Solutions 420,154 19,420,906 20,855 Canada: Traditional 192,661 2,929,568 182,343 Financial Solutions — 25,574 34,471 Europe, Middle East and Africa: Traditional 239,161 1,110,194 977,530 Financial Solutions — 4,540,751 34,514 Asia Pacific: Traditional 702,439 1,738,199 2,436,473 Financial Solutions 18,481 1,043,375 2,365 Corporate and Other — 753,854 5,869 Total $ 3,397,770 $ 43,289,926 $ 5,642,755 2017 U.S. and Latin America: Traditional $ 1,818,572 $ 11,343,921 $ 1,814,018 Financial Solutions 405,623 15,127,529 17,876 Canada: Traditional 212,345 3,041,790 206,655 Financial Solutions — 27,908 1,040 Europe, Middle East and Africa: Traditional 229,150 1,075,786 882,744 Financial Solutions — 4,741,983 38,044 Asia Pacific: Traditional 552,947 1,611,633 2,017,920 Financial Solutions 21,187 1,118,012 6,885 Corporate and Other — 502,321 6,892 Total $ 3,239,824 $ 38,590,883 $ 4,992,074 REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE III—SUPPLEMENTARY INSURANCE INFORMATION (continued) (in thousands) Year ended December 31, Premium Income Net Investment Income Policyholder Benefits and Interest Credited Amortization of DAC Other Expenses (1) 2018 U.S. and Latin America: Traditional $ 5,533,256 $ 729,757 $ 5,130,795 $ 180,407 $ 698,121 Financial Solutions 27,203 706,624 442,071 108,697 105,999 Canada: Traditional 1,024,021 199,412 847,828 13,097 251,171 Financial Solutions 43,372 1,334 36,808 — 2,204 Europe, Middle East and Africa: Traditional 1,423,199 66,242 1,233,458 26,915 179,113 Financial Solutions 195,333 133,855 116,492 — 37,007 Asia Pacific: Traditional 2,296,435 95,521 1,885,355 92,231 261,761 Financial Solutions 866 40,729 39,726 1,691 19,028 Corporate and Other 91 165,051 11,600 — 308,269 Total $ 10,543,776 $ 2,138,525 $ 9,744,133 $ 423,038 $ 1,862,673 2017 U.S. and Latin America: Traditional $ 5,356,321 $ 728,073 $ 4,842,412 $ 191,725 $ 692,600 Financial Solutions 23,683 778,473 458,368 185,280 105,146 Canada: Traditional 901,976 189,018 757,912 12,426 212,964 Financial Solutions 38,229 5,115 29,639 — 2,656 Europe, Middle East and Africa: Traditional 1,301,640 55,511 1,096,211 20,570 174,808 Financial Solutions 163,720 123,258 153,874 — 33,683 Asia Pacific: Traditional 2,053,029 91,675 1,635,728 91,477 334,695 Financial Solutions 2,419 34,529 40,467 1,388 18,790 Corporate and Other 113 148,999 6,346 — 273,789 Total $ 9,841,130 $ 2,154,651 $ 9,020,957 $ 502,866 $ 1,849,131 2016 U.S. and Latin America: Traditional $ 5,249,571 $ 699,833 $ 4,717,850 $ 177,255 $ 698,762 Financial Solutions 24,349 631,097 333,107 133,501 90,458 Canada: Traditional 928,642 178,927 707,428 10,621 265,250 Financial Solutions 38,701 2,692 36,275 — 2,718 Europe, Middle East and Africa: Traditional 1,140,062 50,301 999,005 33,795 132,290 Financial Solutions 180,271 125,282 178,014 — 24,497 Asia Pacific: Traditional 1,681,505 83,049 1,345,951 24,597 286,674 Financial Solutions 5,428 23,648 37,976 1,423 19,920 Corporate and Other 342 117,057 2,460 — 217,738 Total $ 9,248,871 $ 1,911,886 $ 8,358,066 $ 381,192 $ 1,738,307 (1) Includes policy acquisition costs and other insurance expenses, excluding amortization of DAC. Also includes other operating expenses, interest expense, and collateral finance and securitization expense.

Supplemental Schedule of Reinsu

Supplemental Schedule of Reinsurance	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Reinsurance	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE IV—REINSURANCE (in millions) As of or for the Year ended December 31, Gross Amount Ceded to Other Companies Assumed from Other Companies Net Amounts Percentage of Amount Assumed to Net 2018 Life insurance in force $ 1,363 $ 186,172 $ 3,329,181 $ 3,144,372 105.9 % Premiums U.S. and Latin America: Traditional $ 31.6 $ 593.7 $ 6,095.4 5,533.3 110.2 % Financial Solutions 4.7 — 22.5 27.2 82.7 Canada: Traditional — 46.9 1,070.9 1,024.0 104.6 Financial Solutions — — 43.4 43.4 100.0 Europe, Middle East and Africa: Traditional 26.0 25.9 1,423.1 1,423.2 100.0 Financial Solutions 0.2 143.7 338.8 195.3 173.5 Asia Pacific: Traditional — 49.8 2,346.2 2,296.4 102.2 Financial Solutions — — 0.9 0.9 100.0 Corporate and Other — — 0.1 0.1 100.0 Total $ 62.5 $ 860.0 $ 11,341.3 $ 10,543.8 107.6 2017 Life insurance in force $ 1,462 $ 205,529 $ 3,297,275 $ 3,093,208 106.6 % Premiums U.S. and Latin America: Traditional $ 30.5 $ 610.4 $ 5,936.2 $ 5,356.3 110.8 % Financial Solutions 4.3 — 19.4 23.7 81.9 Canada: Traditional — 38.1 940.1 902.0 104.2 Financial Solutions — — 38.2 38.2 100.0 Europe, Middle East and Africa: Traditional 26.6 34.9 1,310.0 1,301.7 100.6 Financial Solutions 0.2 125.0 288.5 163.7 176.2 Asia Pacific: Traditional — 54.5 2,107.5 2,053.0 102.7 Financial Solutions — — 2.4 2.4 100.0 Corporate and Other — — 0.1 0.1 100.0 Total $ 61.6 $ 862.9 $ 10,642.4 $ 9,841.1 108.1 2016 Life insurance in force $ 1,576 $ 214,727 $ 3,062,525 $ 2,849,374 107.5 % Premiums U.S. and Latin America: Traditional $ 31.6 $ 616.0 $ 5,834.0 $ 5,249.6 111.1 % Financial Solutions 1.6 40.2 63.0 24.4 258.2 Canada: Traditional — 36.5 965.1 928.6 103.9 Financial Solutions — — 38.7 38.7 100.0 Europe, Middle East and Africa: Traditional 24.1 30.9 1,146.9 1,140.1 100.6 Financial Solutions 0.3 84.4 264.4 180.3 146.6 Asia Pacific: Traditional — 50.3 1,731.8 1,681.5 103.0 Financial Solutions — — 5.4 5.4 100.0 Corporate and Other — — 0.3 0.3 100.0 Total $ 57.6 $ 858.3 $ 10,049.6 $ 9,248.9 108.7

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE V—VALUATION AND QUALIFYING ACCOUNTS (in millions) Additions Description Balance at Beginning of Period Charged to Costs and Expenses Charged to Other Accounts Deductions Balance at End of Period 2018 Valuation allowance for deferred income taxes $ 226.9 $ (33.7 ) $ (12.1 ) $ — $ 181.1 Valuation allowance for mortgage loans 9.4 1.9 — — 11.3 2017 Valuation allowance for deferred income taxes $ 133.4 $ 88.5 $ 10.6 $ 5.6 $ 226.9 Valuation allowance for mortgage loans 7.7 1.7 — — 9.4 2016 Valuation allowance for deferred income taxes $ 127.1 $ 11.0 $ (4.7 ) $ — $ 133.4 Valuation allowance for mortgage loans 6.8 0.9 — — 7.7

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Consolidation and Basis of Presentation	Basis of Presentation The consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The most significant estimates include those used in determining deferred policy acquisition costs, premiums receivable, future policy benefits, incurred but not reported claims, income taxes, valuation of investments and investment impairments, and valuation of embedded derivatives. Actual results could differ materially from the estimates and assumptions used by management. The accompanying consolidated financial statements include the accounts of RGA and its subsidiaries, all of which are wholly owned, and any variable interest entities where the Company is the primary beneficiary. Entities in which the Company has significant influence over the operating and financing decisions but are not required to be consolidated are reported under the equity method of accounting. The Company evaluates variable interest entities in accordance with the general accounting principles for Consolidation . Intercompany balances and transactions have been eliminated. There were no subsequent events, other than as disclosed in Note 19 - “Subsequent Event,” that would require disclosure or adjustments to the accompanying consolidated financial statements through the date the consolidated financial statements were issued.
Investments	Investments Fixed Maturity Securities Fixed maturity securities classified as available-for-sale are reported at fair value and are so classified based upon the possibility that such securities could be sold prior to maturity if that action enables the Company to execute its investment philosophy and appropriately match investment results to operating and liquidity needs. Unrealized gains and losses on fixed maturity securities classified as available-for-sale, less applicable deferred income taxes as well as related adjustments to deferred acquisition costs, if applicable, are reflected as a direct charge or credit to accumulated other comprehensive income (“AOCI”) in stockholders’ equity on the consolidated balance sheets. Investment income is recognized as it accrues or is legally due. Realized gains and losses on sales of investments are included in investment related gains (losses), net, as are credit impairments that are other-than-temporary in nature. The cost of investments sold is primarily determined based upon the specific identification method. Equity Securities Equity securities are carried at fair value with the exception of the Company’s investment in the Federal Home Loan Bank of Des Moines (“FHLB”) common stock, which is carried at cost and included in other invested assets. Realized and unrealized gains and losses associated with equity securities carried at fair value are included in investment related gains (losses), net. Mortgage Loans on Real Estate Mortgage loans on real estate are carried at unpaid principal balances, net of any unamortized premium or discount and valuation allowances. Interest income is accrued on the principal amount of the mortgage loan based on its contractual interest rate. Amortization of premiums and discounts is recorded using the effective yield method. The Company accrues interest on loans until it is probable the Company will not receive interest or the loan is 90 days past due. Interest income, amortization of premiums, accretion of discounts and prepayment fees are reported in investment income, net of related expenses in the consolidated statements of income. A mortgage loan is considered to be impaired when, based on the current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the mortgage agreement. Although all available and applicable factors are considered in the Company’s analysis, loan-to-value and debt service coverage ratios are the most critical factors in determining impairment. Valuation allowances on mortgage loans are established based upon inherent losses expected by management to be realized in connection with future dispositions or settlement of mortgage loans, including foreclosures. The Company establishes valuation allowances for estimated impairments on an individual loan basis as of the balance sheet date. Such valuation allowances are based on the excess carrying value of the loan over the present value of expected future cash flows discounted at the loan’s original effective interest rate, the value of the loan’s collateral if the loan is in the process of foreclosure or is otherwise collateral-dependent, or the loan’s market value if the loan is being sold. Non-specific valuation allowances are established for mortgage loans based upon several loan factors, including the Company’s historical experience for loan losses, defaults and loss severity, loss expectations for loans with similar risk characteristics and industry statistics. These evaluations are revised as conditions change and new information becomes available. In addition to historical experience, management considers qualitative factors that include the impact of changing macro-economic conditions, which may not be currently reflected in the loan portfolio performance, and the quality of the loan portfolio. Any interest accrued or received on the net carrying amount of the impaired loan will be included in investment income or applied to the principal of the loan, depending on the assessment of the collectability of the loan. Mortgage loans deemed to be uncollectible or that have been foreclosed are charged off against the valuation allowances and subsequent recoveries, if any, are credited to the valuation allowances. Changes in valuation allowances are reported in investment related gains (losses), net on the consolidated statements of income. The Company evaluates whether a mortgage loan modification represents a troubled debt restructuring. In a troubled debt restructuring, the Company grants concessions related to the borrower’s financial difficulties. Generally, the types of concessions include: reduction of the contractual interest rate, extension of the maturity date at an interest rate lower than current market interest rates and/or a reduction of accrued interest. The Company considers the amount, timing and extent of the concession granted in determining any impairment or changes in the specific valuation allowance recorded in connection with the troubled debt restructuring. Through the continuous monitoring process, the Company may have recorded a specific valuation allowance prior to when the mortgage loan is modified in a troubled debt restructuring. Accordingly, the carrying value (after specific valuation allowance) before and after modification through a troubled debt restructuring may not change significantly, or may increase if the expected recovery is higher than the pre-modification recovery assessment. Funds Withheld at Interest Funds withheld at interest represent amounts contractually withheld by ceding companies in accordance with reinsurance agreements. For agreements written on a modified coinsurance (“modco”) basis and agreements written on a coinsurance funds withheld basis, assets that support the net statutory reserves or as defined in the treaty, are withheld and legally owned by the ceding company. Interest, recorded in investment income, net of related expenses in the consolidated statements of income, accrues to these assets at calculated rates as defined by the treaty terms. Changes in the value of the equity options held within the funds withheld portfolio associated with equity-indexed annuity treaties are reflected in investment income, net of related expenses. Short-term Investments Short-term investments represent investments with remaining maturities of one year or less, but greater than three months, at the time of acquisition and are stated at estimated fair value or amortized cost, which approximates estimated fair value. Interest on short-term investments is recorded in investment income, net of related expenses in the consolidated statements of income. Other Invested Assets In addition to FHLB common stock discussed in the Equity Securities section above and derivative contracts discussed below, other invested assets include limited partnership interests, joint ventures (other than operating joint ventures), equity release mortgages and contractholder-directed investments. Limited partnership interests are primarily carried at cost. Based on the nature and structure of these investments, they do not meet the characteristics of an equity security in accordance with applicable accounting standards. Joint ventures and certain limited partnerships are reported using the equity method of accounting. Equity release mortgages are carried at unpaid principal balances, net of any unamortized premium or discount and valuation allowance. Interest income is accrued on the principal amount of the equity release mortgage based on its contractual interest rate. The fair value option (“FVO”) was elected for contractholder-directed investments supporting unit-linked variable annuity type liabilities that do not qualify for presentation and reporting as separate accounts. Changes in estimated fair value of these securities are included in investment income, net of related expenses. Securities Borrowing, Lending and Repurchase Agreements The Company participates in securities borrowing programs whereby securities, which are not reflected on the Company’s consolidated balance sheets, are borrowed from third parties. The borrowed securities are used to provide collateral under affiliated reinsurance transactions. The Company is required to maintain a minimum of 100% of the fair value, or par value under certain programs, of the borrowed securities as collateral. The collateral consists of rights to reinsurance treaty cash flows. If cash flows from the reinsurance treaties are insufficient to maintain the minimum collateral requirement, the Company may substitute cash or securities to meet the requirement. The Company participates in a securities lending program whereby securities, reflected as investments on the Company’s consolidated balance sheets, are loaned to a third party. The Company receives securities as collateral, in an amount equal to a minimum of 105% of the fair value of the securities lent. The securities received as collateral are not reflected on the Company’s consolidated balance sheets. The Company participates in a repurchase program in which securities, reflected as investments on the Company’s consolidated balance sheets, are pledged to a third party. In return, the Company receives cash from the third party, which is reflected as a payable to a third party, included in other liabilities on the consolidated balance sheets. The Company is required to maintain a minimum collateral balance with a fair value of 105% of the cash received. The Company participates in repurchase/reverse repurchase programs in which securities, reflected as investments on the Company’s consolidated balance sheets, are pledged to third parties. In return, the Company receives securities from the third parties with an estimated fair value equal to a minimum of 100% of the securities pledged. The securities received are not reflected on the Company’s consolidated balance sheets. Other-than-Temporary Impairment The Company identifies fixed maturity securities that could potentially have credit impairments that are other-than-temporary by monitoring market events that could impact issuers’ credit ratings, business climates, management changes, litigation, government actions and other similar factors. The Company also monitors late payments, pricing levels, rating agency actions, key financial ratios, financial statements, revenue forecasts and cash flow projections as indicators of credit issues. The Company reviews all securities on a case-by-case basis to determine whether an other-than-temporary decline in value exists and whether losses should be recognized. The Company considers relevant facts and circumstances in evaluating whether a credit or interest rate-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 or amortized cost; (2) the reasons for the decline in fair value; (3) the issuer’s financial position and access to capital; and (4) the Company’s intent to sell a security or whether it is more likely than not it will be required to sell the security before the recovery of its amortized cost that, in some cases, may extend to maturity. To the extent the Company determines that a security is deemed to be other-than-temporarily impaired, an impairment loss is recognized. Impairment losses on fixed maturity securities recognized in the financial statements are dependent on the facts and circumstances related to the specific security. If the Company intends to sell a security or it is more likely than not that it would be required to sell a security before the recovery of its amortized cost, less any recorded credit loss, it recognizes an other-than-temporary impairment in investment related gains (losses), net on the consolidated statements of income for the difference between amortized cost and fair value. If neither of these two conditions exists then the recognition of the other-than-temporary impairment is bifurcated and the Company recognizes the credit loss portion in investment related gains (losses), net and the non-credit loss portion in AOCI. The Company estimates 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 techniques and assumptions for establishing the best estimate cash flows vary depending on the type of security. The asset-backed securities’ 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 fixed maturity security cash flow estimates are derived from scenario-based outcomes of expected corporate restructurings or the disposition of assets using security specific facts and circumstances including timing, security interests and loss severity. In periods after an other-than-temporary impairment loss is recognized on a fixed maturity security, the Company will report the impaired security as if it had been purchased on the date it was impaired and will continue to estimate the present value of the estimated cash flows of the security. Accordingly, the discount (or reduced premium) based on the new cost basis is accreted into net investment income over the remaining term of the fixed maturity security in a prospective manner based on the amount and timing of estimated future cash flows. The Company considers its cost method investments for other-than-temporary impairment when the carrying value of these investments exceeds the net asset value. The Company takes into consideration the severity and duration of this excess when deciding if the cost method investment is other-than-temporarily impaired. For equity method investments (including real estate joint ventures), the Company considers financial and other information provided by the investee, other known information and inherent risks in the underlying investments, as well as future capital commitments, in determining whether an impairment has occurred.
Policy Loans Receivable	Policy Loans Policy loans are reported at the unpaid principal balance. Interest income on such loans is recorded as earned using the contractually agreed-upon interest rate. These policy loans present no credit risk because the amount of the loan cannot exceed the obligation due the ceding company upon the death of the insured or surrender of the underlying policy.
Derivative Instruments	Derivative Instruments Overview The Company utilizes a variety of derivative instruments including swaps, options, forwards and futures, primarily to manage or hedge interest rate risk, credit risk, inflation risk, foreign currency risk, market volatility and various other market risks associated with its business. The Company does not invest in derivatives for speculative purposes. It is the Company’s policy to enter into derivative contracts primarily with highly rated parties. See Note 5 - “Derivative Instruments” for additional detail on the Company’s derivative positions. Accounting and Financial Statement Presentation of Derivatives Derivatives are carried on the Company’s consolidated balance sheets primarily in other invested assets or other liabilities, at fair value. Certain derivatives are subject to master netting provisions and reported as a net asset or liability. On the date a derivative contract is executed, the Company designates the derivative as (1) a fair value hedge, (2) a cash flow hedge, (3) a net investment hedge in a foreign operation or (4) free-standing derivatives held for other risk management purposes, which primarily involve managing asset or liability risks associated with the Company’s reinsurance treaties that do not qualify for hedge accounting. Changes in the fair value of free-standing derivative instruments, which do not receive accounting hedge treatment, are primarily reflected in investment related gains (losses), net. Changes in the fair value of non-investment free-standing derivative instruments (e.g. mortality and longevity swaps), which do not receive accounting hedge treatment, are reflected in other revenues. Hedge Documentation and Hedge Effectiveness To qualify for hedge accounting, at the inception of the hedging relationship, the Company formally documents its risk management objective and strategy for undertaking the hedging transaction, as well as its designation of the hedge as either (i) a fair value hedge; (ii) a cash flow hedge; or (iii) a hedge of a net investment in a foreign operation. In this documentation, the Company sets forth how the hedging instrument is expected to hedge the designated risks related to the hedged item and sets forth the method that will be used to retrospectively and prospectively assess the hedging instrument’s effectiveness and the method that will be used to measure ineffectiveness. A derivative designated as a hedging instrument must be assessed as being highly effective in offsetting the designated risk of the hedged item. Hedge effectiveness is formally assessed at inception and periodically throughout the life of the designated hedging relationship. Under a fair value hedge, changes in the fair value of the hedging derivative, including amounts measured as ineffective, and changes in the fair value of the hedged item related to the designated risk being hedged, are reported within investment related gains (losses), net. The fair values of the hedging derivatives are exclusive of any accruals that are separately reported in the consolidated statements of income within interest income or interest expense to match the location of the hedged item. Under a cash flow hedge, changes in the fair value of the hedging derivative measured as effective are reported within AOCI and the deferred gains or losses on the derivative are reclassified into the consolidated statements of income when the Company’s earnings are affected by the variability in cash flows of the hedged item. Changes in the fair value of the hedging instrument measured as ineffective are reported within investment related gains (losses), net. The fair values of the hedging derivatives are exclusive of any accruals that are separately reported in the consolidated statements of income within interest income or interest expense to match the location of the hedged item. In a hedge of a net investment in a foreign operation, changes in the fair value of the hedging derivative that are measured as effective are reported within AOCI consistent with the translation adjustment for the hedged net investment in the foreign operation. Changes in the fair value of the hedging instrument measured as ineffective are reported within investment related gains (losses), net. The Company discontinues hedge accounting prospectively when: (i) it is determined that the derivative is no longer highly effective in offsetting changes in the estimated fair value or cash flows of a hedged item; (ii) the derivative expires, is sold, terminated, or exercised; (iii) it is no longer probable that the hedged forecasted transaction will occur; or (iv) the derivative is de-designated as a hedging instrument. When hedge accounting is discontinued because it is determined that the derivative is not highly effective, the derivative continues to be carried in the consolidated balance sheets at fair value, with changes in fair value recognized in investment related gains (losses), net. The carrying value of the hedged asset or liability under a fair value hedge is no longer adjusted for changes in its estimated fair value due to the hedged risk, and the cumulative adjustment to its carrying value is amortized into income over the remaining life of the hedged item. Provided the hedged forecasted transaction occurrence is still probable, the changes in estimated fair value of derivatives recorded in other comprehensive income (loss) (“OCI”) related to discontinued cash flow hedges are released into the consolidated statements of income when the Company’s earnings are affected by the variability in cash flows of the hedged item. When hedge accounting is discontinued because it is no longer probable that the forecasted transactions will occur on the anticipated date or within two months of that date, the derivative continues to be carried in the consolidated balance sheets at its estimated fair value, with changes in estimated fair value recognized currently in investment related gains (losses), net. Deferred gains and losses of a derivative recorded in OCI pursuant to the discontinued cash flow hedge of a forecasted transaction that is no longer probable are recognized immediately in investment related gains (losses), net. In all other situations in which hedge accounting is discontinued, the derivative is carried at its estimated fair value in the consolidated balance sheets, with changes in its estimated fair value recognized in the current period as investment related gains (losses), net. Embedded Derivatives The Company reinsures certain annuity products that contain terms that are deemed to be embedded derivatives, primarily equity-indexed annuities and variable annuities with guaranteed minimum benefits. The Company assesses reinsurance contract terms to identify embedded derivatives, which are required to be bifurcated under the general accounting principles for Derivatives and Hedging . If the contract is not reported for in its entirety at fair value and it is determined that the terms of the embedded derivative are not clearly and closely related to the economic characteristics of the host contract, and that a separate instrument with the same terms would qualify as a derivative instrument, the embedded derivative is bifurcated from the host contract and accounted for separately. Such embedded derivatives are carried on the consolidated balance sheets at fair value in the same line item as the host contract. Changes in the fair value of embedded derivatives associated with equity-indexed annuities are reflected in interest credited on the consolidated statements of income and changes in the fair value of embedded derivatives associated with variable annuity guaranteed minimum benefits are reflected in investment related gains (losses), net on the consolidated statements of income. See “Interest-Sensitive Contract Liabilities” below for additional information on embedded derivatives related to equity-indexed and variable annuities. The Company has implemented an economic hedging strategy to mitigate the volatility associated with its reinsurance of variable annuity guaranteed minimum benefits. The hedging strategy is designed such that changes in the fair value of the hedge contracts, primarily futures, swap contracts and options, move in the opposite direction of changes in the fair value of the embedded derivatives. While the Company actively manages its hedging program, the hedges that are in place may not be totally effective in offsetting the embedded derivative changes due to the many variables that must be managed and the Company may see a corresponding increase or decrease in the net liability. The Company has elected not to assess this hedging strategy for hedge accounting treatment. Additionally, reinsurance treaties written on a modco or funds withheld basis are subject to the general accounting principles for Derivatives and Hedging related to embedded derivatives. The Company’s funds withheld at interest balances are primarily associated with its reinsurance treaties structured on a modco or funds withheld basis, the majority of which were subject to the general accounting principles for Derivatives and Hedging related to embedded derivatives. Management believes the embedded derivative feature in each of these reinsurance treaties is similar to a total return swap on the assets held by the ceding companies. The valuation of embedded derivatives is sensitive to the investment credit spread environment. Changes in investment credit spreads are also affected by the application of a credit valuation adjustment (“CVA”). The fair value calculation of an embedded derivative in an asset position utilizes a CVA based on the ceding company’s credit risk. Conversely, the fair value calculation of an embedded derivative in a liability position utilizes a CVA based on the Company’s credit risk. Generally, an increase in investment credit spreads, ignoring changes in the CVA, will have a negative impact on the fair value of the embedded derivative (decrease in income). The fair value of the embedded derivatives is included in the funds withheld at interest line item on the consolidated balance sheets. The change in the fair value of the embedded derivatives is recorded in investment related gains (losses), net on the consolidated statements of income. The Company has entered into various financial reinsurance treaties on a funds withheld and modco basis. These treaties do not transfer significant insurance risk and are recorded on a deposit method of accounting with the Company earning a net fee. As a result of the experience refund provisions contained in these treaties, the value of the embedded derivatives in these contracts is currently considered immaterial. The Company monitors the performance of these treaties on a quarterly basis. Significant adverse performance or losses on these treaties may result in a loss associated with the embedded derivative.
Fair Value Measurements	Fair Value Measurements General accounting principles for Fair Value Measurements and Disclosures define fair value, establish a framework for measuring fair value, establish a fair value hierarchy based on the inputs used to measure fair value and enhance disclosure requirements for fair value measurements. In compliance with these principles, the Company has categorized its assets and liabilities, based on the priority of the inputs to the valuation technique, into a three level hierarchy or separately for assets measured using the net asset value (“NAV”). The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1), the second highest priority to quoted prices in markets that are not active or inputs that are observable either directly or indirectly (Level 2) and the lowest priority to unobservable inputs (Level 3). If the inputs used to measure fair value fall within different levels of the hierarchy, the category level is based on the lowest priority level input that is significant to the fair value measurement of the asset or liability. See Note 6 - “Fair Value of Assets and Liabilities” for further details on the Company’s assets and liabilities recorded at fair value.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash on deposit and highly liquid debt instruments purchased with an original maturity of three months or less.
Premiums Receivable	Premiums Receivable Premiums are accrued when due and in accordance with information received from the ceding company. When the Company enters into a new reinsurance agreement, it records accruals based on the terms of the reinsurance treaty. Similarly, when a ceding company fails to report information on a timely basis, the Company records accruals based on the terms of the reinsurance treaty as well as historical experience. Other management estimates include adjustments for increased in force on existing treaties, lapsed premiums given historical experience, the financial health of specific ceding companies, collateral value and the legal right of offset on related amounts (i.e. allowances and claims) owed to the ceding company. Under the legal right of offset provisions in its reinsurance treaties, the Company can withhold payments for allowances and claims from unpaid premiums. Based on its review of these factors and historical experience, the Company did not believe a provision for doubtful accounts was necessary as of December 31, 2018 or 2017 .
Deferred Policy Acquisition Costs	Deferred Policy Acquisition Costs Costs of acquiring new business, which vary with and are directly related to the production of new business, have been deferred to the extent that such costs are deemed recoverable from future premiums or gross profits. Such costs include commissions and allowances as well as certain costs of policy issuance and underwriting. Non-commission costs related to the acquisition of new and renewal insurance contracts may be deferred only if they meet the following criteria: • Incremental direct costs of a successful contract acquisition • Portions of employees’ salaries and benefits directly related to time spent performing specified acquisition activities for a contract that has been acquired or renewed • Other costs directly related to the specified acquisition or renewal activities that would not have been incurred had that acquisition contract transaction not occurred The Company tests the recoverability for each year of business at issue before establishing additional deferred acquisition costs (“DAC”). The Company also performs annual tests to establish that DAC are expected to remain recoverable, and if financial performance significantly deteriorates to the point where a deficiency exists, a cumulative charge to current operations will be recorded. No such adjustments related to DAC recoverability were made in 2018, 2017 and 2016 . DAC related to traditional life insurance contracts are amortized with interest over the premium-paying period of the related policies in proportion to the ratio of individual period premium revenues to total anticipated premium revenues over the life of the policy. Such anticipated premium revenues are estimated using the same assumptions used for computing liabilities for future policy benefits. DAC related to interest-sensitive life and investment-type policies are amortized over the lives of the policies, in proportion to the gross profits realized from mortality, investment income less interest credited, and expense margins.
Other Reinsurance Balances	Other Reinsurance Balances The Company assumes and retrocedes financial reinsurance contracts that do not expose it to a reasonable possibility of loss from insurance risk. These contracts are reported as deposits and are included in other reinsurance assets/liabilities. The amount of revenue reported in other revenues on these contracts represents fees and the cost of insurance under the terms of the reinsurance agreement. Assets and liabilities are reported on a net or gross basis, depending on the specific details within each treaty. Reinsurance agreements reported on a net basis, where a legal right of offset exists, are generally included in other reinsurance balances on the consolidated balance sheets. Balances resulting from the assumption and/or subsequent transfer of benefits and obligations resulting from cash flows related to variable annuities have also been classified as other reinsurance balance assets and/or liabilities. Other reinsurance assets are included in premiums receivable and other reinsurance balances while other reinsurance liabilities are included in other reinsurance balances on the consolidated balance sheets.
Goodwill and Value of Business Acquired	Goodwill and Value of Business Acquired Goodwill, reported in other assets, is not amortized into results of operations, but instead is reviewed at least annually for impairment and written down only in the periods in which the recorded value of goodwill exceeds its fair value. Goodwill as of December 31, 2018 and 2017 totaled $7.0 million . The value of business acquired (“VOBA”) is amortized in proportion to the ratio of annual premium revenues to total anticipated premium revenues or in relation to the present value of estimated profits. Anticipated premium revenues have been estimated using assumptions consistent with those used in estimating reserves for future policy benefits. The carrying value is reviewed at least annually for indicators of impairment in value. The VOBA was approximately $5.1 million and $3.3 million , including accumulated amortization of $15.0 million and $14.6 million , as of December 31, 2018 and 2017 , respectively. The VOBA amortization expense for the years ended December 31, 2018, 2017 and 2016 was $0.4 million , $0.3 million , and $0.5 million , respectively. These amortized balances are included in other assets on the consolidated balance sheets. Future amortization of the VOBA is not material.
Value of Distribution Agreements and Customer Relationships Acquired	Value of Distribution Agreements and Customer Relationships Acquired Value of distribution agreements (“VODA”) is reported in other assets and represents the present value of future profits associated with the expected future business derived from the distribution agreements. Value of customer relationships acquired (“VOCRA”) is also reported in other assets and represents the present value of the expected future profits associated with the expected future business acquired through existing customers of the acquired company or business. The VODA is amortized over a useful life of 15 years and the VOCRA is also amortized over a 15 year period in proportion to expected revenues generated, with amortization included in policy acquisition costs and other insurance expenses. Each year the Company reviews VODA and VOCRA to determine the recoverability of these balances. VODA and VOCRA totaled approximately $40.8 million and $49.2 million , including accumulated amortization of $79.8 million and $71.5 million , as of December 31, 2018 and 2017 , respectively. The VODA and VOCRA amortization expense for the years ended December 31, 2018, 2017 and 2016 was $8.3 million , $8.7 million and $9.0 million , respectively. Amortization of the VODA and VOCRA is estimated to be $8.1 million , $7.6 million , $6.6 million , $6.4 million and $6.2 million during 2019, 2020, 2021, 2022 and 2023, respectively. Other acquired intangible assets Other acquired intangibles are also reported in other assets and primarily represent intangibles and licenses acquired through the Company’s acquisition of service and technology oriented companies in an effort to both support its clients and generate new future revenue streams. Other acquired intangible assets are amortized using the straight-line method over the estimated useful life of 10 years, with amortization included in other operating expenses. Each year the Company reviews other acquired intangibles to determine the recoverability of these balances. Other acquired intangibles totaled approximately $37.4 million and $3.1 million , including accumulated amortization of $4.4 million and $0.6 million , as of December 31, 2018 and 2017, respectively. Other acquired intangibles amortization expense for the years ended December 31, 2018, 2017 and 2016 was $3.8 million , $0.3 million and $0.2 million , respectively. Amortization of other acquired intangibles is estimated to be $4.2 million , $4.2 million , $4.1 million , $4.1 million and $4.1 million during 2019, 2020, 2021, 2022 and 2023, respectively.
Other Assets	Property, Equipment, Leasehold Improvements and Computer Software Property, equipment and leasehold improvements, which are included in other assets, are stated at cost, less accumulated depreciation. Depreciation is determined using the straight-line method over the estimated useful lives of the assets, as appropriate. The estimated life is generally 40 years for company occupied real estate property, from one to seven years for leasehold improvements, and from three to seven years for all other property and equipment. The cost basis of the property, equipment and leasehold improvements was $248.7 million and $236.1 million at December 31, 2018 and 2017 , respectively. Accumulated depreciation of property, equipment and leasehold improvements was $97.0 million and $79.4 million at December 31, 2018 and 2017 , respectively. Related depreciation expense was $18.3 million , $17.2 million and $16.6 million for the years ended December 31, 2018, 2017 and 2016 , respectively. Computer software, which is included in other assets, is stated at cost, less accumulated amortization. Purchased software costs, as well as certain internal and external costs incurred to develop internal-use computer software during the application development stage, are capitalized. Amortization of software costs is recorded on a straight-line basis over periods ranging from three to ten years. Carrying values are reviewed at least annually for indicators of impairment in value. Unamortized computer software costs were $150.4 million and $145.5 million at December 31, 2018 and 2017 , respectively. Amortization expense was $26.9 million , $35.7 million , and $10.3 million for the years ended December 31, 2018, 2017 and 2016 , respectively. The Company recognized capital project write-offs of $4.7 million , $24.5 million and $0.6 million in 2018, 2017 and 2016 , respectively.
Future Policy Benefits	Future Policy Benefits Liabilities for future benefits on life policies are established in an amount adequate to meet the estimated future obligations on policies in force. Liabilities for future policy benefits under long-duration life insurance policies have been computed based upon expected investment yields, mortality and withdrawal (lapse) rates, and other assumptions. These assumptions include a margin for adverse deviation and vary with the characteristics of the plan of insurance, year of issue, age of insured, and other appropriate factors. Interest rates range from 3.0% to 6.0% . The mortality and withdrawal assumptions are based on the Company’s experience as well as industry experience and standards. In establishing reserves for future policy benefits, the Company assigns policy liability assumptions to particular timeframes (eras) in such a manner as to be consistent with the underlying assumptions and economic conditions at the time the risks are assumed. The Company maintains a consistent approach to setting the provision for adverse deviation between eras. Liabilities for future benefits on longevity business, including annuities in the payout phase, are established in an amount adequate to meet the estimated future obligations on policies in force. Liabilities for future benefits related to the longevity business, including annuities in the payout phase have been calculated using expected mortality, investment yields, and other assumptions. These assumptions include a margin for adverse deviation and vary with the characteristics of the plan of insurance, year of issue, age of insured, and other appropriate factors. The mortality assumptions are based on the Company’s experience as well as industry experience and standards. A deferred profit liability is established when the gross premium exceeds the net premium. The Company periodically reviews actual and anticipated experience compared to the assumptions used to establish policy benefits. The Company establishes premium deficiency reserves if actual and anticipated experience indicates that existing policy liabilities together with the present value of future gross premiums will not be sufficient to cover the present value of future benefits, settlement and maintenance costs and to recover unamortized acquisition costs. Anticipated investment income is considered in the calculation of premium deficiency losses for short-duration contracts. The premium deficiency reserve is established by a charge to income, as well as a reduction in unamortized acquisition costs and, to the extent there are no unamortized acquisition costs, an increase in future policy benefits. The reserving process includes normal periodic reviews of assumptions used and adjustments of reserves to incorporate the refinement of the assumptions. Any such adjustments relate only to policies assumed in recent periods and the adjustments are reflected by a cumulative charge or credit to current operations. The Company reinsures disability products in various markets. Liabilities for future benefits on disability policies’ active lives are established in an amount adequate to meet the estimated future obligations on policies in force. These reserves are the amounts that, with the additional premiums to be received and interest thereon compounded annually at certain assumed rates, are calculated to be sufficient to meet the various policy and contract obligations as they mature. The Company establishes future policy benefits for guaranteed minimum death benefits (“GMDB”) relating to the reinsurance of certain variable annuity contracts by estimating the expected value of death benefits in excess of the projected account balance and recognizing the excess proportionally over the accumulation period based on total expected assessments. The Company regularly evaluates estimates used and adjusts the additional liability balance, with a related charge or credit to claims and other policy benefits, if actual experience or other evidence suggests that earlier assumptions should be revised. The assumptions used in estimating the GMDB liabilities are consistent with those used for amortizing DAC, and are thus subject to the same variability and risk. The Company’s GMDB liabilities at December 31, 2018 and 2017 were not material.
Interest-Sensitive Contract Liabilities	Interest-Sensitive Contract Liabilities Liabilities for future benefits on interest-sensitive life and investment-type contract liabilities are carried at the accumulated contract holder values without reduction for potential surrender or withdrawal charges. The Company reinsures asset-intensive products, including annuities and corporate-owned life insurance. The investment portfolios for these products are segregated for management purposes within the general account of the respective legal entity. The liabilities under asset-intensive insurance contracts or reinsurance contracts reinsured on a coinsurance basis are included in interest-sensitive contract liabilities on the consolidated balance sheets. Asset-intensive contracts principally include individual fixed annuities in the accumulation phase, single premium immediate annuities, equity-indexed annuities, individual variable annuities, corporate-owned life and interest-sensitive whole life insurance contracts. Interest-sensitive contract liabilities are equal to (i) policy account values, which consist of an accumulation of gross premium payments; (ii) credited interest less expenses, mortality charges, and withdrawals; and (iii) fair value adjustments relating to business combinations. Liabilities for immediate annuities are calculated as the present value of the expected cash flows, with the locked-in discount rate determined such that there is no gain or loss at inception. Additionally, certain annuity contracts the Company reinsures contain terms, such as guaranteed minimum benefits and equity participation options, which are deemed to be embedded derivatives and are accounted for based on the general accounting principles for Derivatives and Hedging . The Company establishes liabilities for guaranteed minimum living benefits relating to certain variable annuity products as follows: Guaranteed minimum income benefits (“GMIB”) provide the contract holder, after a specified period of time determined at the time of issuance of the variable annuity contract, with a minimum level of income (annuity) payments. Under the reinsurance treaty, the Company makes a payment to the ceding company equal to the GMIB net amount-at-risk at the time of annuitization and thus these contracts meet the net settlement criteria of the general accounting principles for Derivatives and Hedging and the Company assumes no mortality risk. Accordingly, the GMIB is considered an embedded derivative, which is measured at fair value separately from the host variable annuity product. Guaranteed minimum withdrawal benefits (“GMWB”) guarantee the contract holder a return of their purchase payment via partial withdrawals, even if the account value is reduced to zero, provided that the contract holder’s cumulative withdrawals in a contract year do not exceed a certain limit. The initial guaranteed withdrawal amount is equal to the initial benefit base as defined in the contract (typically, the initial purchase payments plus applicable bonus amounts). The GMWB is also an embedded derivative, which is measured at fair value separately from the host variable annuity product. Guaranteed minimum accumulation benefits (“GMAB”) provide the contract holder, after a specified period of time determined at the time of issuance of the variable annuity contract, with a minimum accumulation of their purchase payments even if the account value is reduced to zero. The initial guaranteed accumulation amount is equal to the initial benefit base as defined in the contract (typically, the initial purchase payments plus applicable bonus amounts). The GMAB is also an embedded derivative, which is measured at fair value separately from the host variable annuity product. For GMIB, GMWB and GMAB, the initial benefit base is increased by additional purchase payments made within a certain time period and decreased by benefits paid and/or withdrawal amounts. After a specified period of time, the benefit base may also increase as a result of an optional reset as defined in the contract. The fair values of the GMIB, GMWB and GMAB embedded derivative liabilities are reflected in interest-sensitive contract liabilities on the consolidated balance sheets and are calculated based on actuarial and capital market assumptions related to the projected cash flows, including benefits and related contract charges over the lives of the contracts. These projected cash flows incorporate expectations concerning policyholder behavior, such as lapses, withdrawals and benefit selections, and capital market assumptions such as interest rates and equity market volatilities. In measuring the fair value of GMIBs, GMWBs and GMABs, the Company attributes a portion of the fees collected from the policyholder equal to the present value of expected future guaranteed minimum income, withdrawal and accumulation benefits (at inception). The changes in fair value are reported in investment related gains (losses), net. Any additional fees represent “excess” fees and are reported in other revenues on the consolidated statements of income. These variable annuity guaranteed living benefits may be more costly than expected in volatile or declining equity markets or falling interest rate markets, causing an increase in interest-sensitive contract liabilities, negatively affecting net income. The Company reinsures equity-indexed annuity contracts. These contracts allow the contract holder to elect an interest rate return or an equity market component where interest credited is based on the performance of common stock market indices, such as the S&P 500 Index ® , the Dow Jones Industrial Average, or the NASDAQ. The equity market option is considered an embedded derivative, similar to a call option, which is reflected at fair value on the consolidated balance sheets in interest-sensitive contract liabilities. The fair value of embedded derivatives is computed based on a projection of future equity option costs using a budget methodology, discounted back to the balance sheet date using current market indicators of volatility and interest rates. Changes in the fair value of the embedded derivatives are included as a component of interest credited on the consolidated statements of income. The Company reviews its estimates of actuarial liabilities for interest-sensitive contract liabilities and compares them with its actual experience. Differences between actual experience and the assumptions used in pricing these guarantees and benefits and in the establishment of the related liabilities result in variances in profit and could result in losses. The effects of changes in such estimated liabilities are included in the results of operations in the period in which the changes occur.
Other Policy Claims and Benefits	Other Policy Claims and Benefits Claims payable for incurred but not reported losses are determined using case-basis estimates and lag studies of past experience. The time lag from the date of the claim or death to when the ceding company reports the claim to the Company can vary significantly by ceding company, business segment and product type, but generally averages around 3.8 months. Incurred but not reported claims are estimates on an undiscounted basis, using actuarial estimates of historical claims expense, adjusted for current trends and conditions. These estimates are continually reviewed and the ultimate liability may vary significantly from the amount recognized, which are reflected in claims and other policy benefits in the consolidated statements of income in the period in which they are determined.
Other Liabilities	Other Liabilities Other liabilities primarily include investments in transit, separate accounts, employee benefits, cash collateral received on derivative positions and current federal income taxes payable.
Income Taxes	Income Taxes The U.S. consolidated tax return includes the operations of RGA and all eligible subsidiaries. Certain RGA subsidiaries file separate U.S. income tax returns as these companies are currently ineligible for inclusion in the consolidated federal tax return. The Company’s foreign subsidiaries are taxed under applicable local statutes. The Company provides for federal, state and foreign income taxes currently payable, as well as those deferred due to temporary differences between the tax basis of assets and liabilities and the reported amounts, and are recognized in net income or in certain cases in OCI. The Company’s accounting for income taxes represents management’s best estimate of various events and transactions considering the laws enacted as of the reporting date. The Tax Cuts and Jobs Act of 2017 (“U.S. Tax Reform”) creates additional complexity due to various provisions that require management judgment and assumptions, which are subject to change. Deferred tax assets and liabilities are measured by applying the relevant jurisdictions’ enacted tax rate to the temporary difference in the period in which the temporary differences are expected to reverse. The Company will establish a valuation allowance if management determines, based on available information, that it is more likely than not that deferred income tax assets will not be realized. The Company has deferred tax assets including those related to net operating and capital losses. The Company has projected its ability to utilize its U.S. and foreign deferred tax assets and has determined that all of the U.S. assets including losses are expected to be utilized and established a valuation allowance on the portion of the foreign deferred tax assets the Company believes more likely than not will not be realized. Significant judgment is required in determining whether valuation allowances should be established as well as the amount of such allowances. When making such a determination, consideration is given to, among other things, the following: (i) future taxable income exclusive of reversing temporary differences and carryforwards; (ii) future reversals of existing taxable temporary differences; (iii) taxable income in prior carryback years; and (iv) tax planning strategies. Any such changes could significantly affect the amounts reported in the consolidated financial statements in the year these changes occur. The Company reports uncertain tax positions in accordance with generally accepted accounting principles. In order to recognize the benefit of an uncertain tax position, the position must meet the more likely than not criteria of being sustained. Unrecognized tax benefits due to tax uncertainties that do not meet the more likely than not criteria are included within other liabilities and are charged to earnings in the period that such determination is made. The Company classifies interest related to tax uncertainties as interest expense whereas penalties related to tax uncertainties are classified as a component of income tax.
Collateral Finance Facility	Collateral Finance and Securitization Notes Collateral finance and securitization notes represent private placement asset-backed structured financing transactions. Collateral finance notes are issued on specified insurance policies reinsured by the Company’s regulated subsidiaries. Transaction costs, primarily interest expense, are reflected in collateral finance and securitization expense. See Note 14 - “Collateral Finance and Securitization Notes” for additional information.
Foreign Currency Translation	Foreign Currency Translation Assets, liabilities and results of foreign operations are recorded based on the functional currency of each foreign operation. The determination of the functional currency is based on economic facts and circumstances pertaining to each foreign operation. The Company’s material functional currencies are the U.S. dollar, Canadian dollar, British pound, Australian dollar, Japanese yen, Korean won, Euro and South African rand. The translation of the functional currency into U.S. dollars is performed for balance sheet accounts using current exchange rates in effect at the balance sheet date and for revenue and expense accounts using weighted-average exchange rates during each year. Gains or losses, net of applicable deferred income taxes, resulting from such translation are included in accumulated currency translation adjustments, in AOCI on the consolidated balance sheets until the underlying functional currency operation is sold or substantially liquidated.
Recognition of Revenues and Related Expenses	Recognition of Revenues and Related Expenses Life and health premiums are recognized as revenue when due from the insured, and are reported net of amounts retroceded. Benefits and expenses are reported net of amounts retroceded and are associated with earned premiums so that profits are recognized over the life of the related contract. This association is accomplished through the provision for future policy benefits and the amortization of deferred policy acquisition costs. Other revenue includes items such as treaty recapture fees, fees associated with financial reinsurance and policy changes on interest-sensitive and investment-type products that the Company reinsures. Any fees that are collected in advance of the period benefited are deferred and recognized over the period benefited. For certain reinsurance transactions involving in force blocks of business, the ceding company pays a premium equal to the initial required reserve (future policy benefit). In such transactions, for income statement presentation, the Company nets the expense associated with the establishment of the reserve on the consolidated balance sheets against the premiums from the transaction. Revenues for interest-sensitive and investment-type products consist of investment income, policy charges for the cost of insurance, policy administration, and surrenders that have been assessed against policy account balances during the period. Interest-sensitive contract liabilities for these products represent policy account balances before applicable surrender charges. Policy benefits and claims that are charged to expenses include claims incurred in the period in excess of related policy account balances and interest credited to policy account balances. Interest is credited to policyholder account balances according to terms of the policies or contracts. For each of its reinsurance contracts, the Company must determine if the contract provides indemnification against loss or liability relating to insurance risk, in accordance with GAAP. The Company must review all contractual features, particularly those that may limit the amount of insurance risk to which the Company is subject or features that delay the timely reimbursement of claims. If the Company determines that a contract does not expose it to a reasonable possibility of a significant loss from insurance risk, the Company records the contract on a deposit method of accounting with any net amount receivable reflected as an asset within premiums receivable and other reinsurance balances, and any net amount payable reflected as a liability within other reinsurance balances on the consolidated balance sheets. Fees earned on the contracts are reflected as other revenues, rather than premiums, on the consolidated statements of income.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Equity Based Compensation The Company expenses the fair value of stock awards included in its incentive compensation plans. As of the date stock awards are approved, the fair value of stock options is determined using a Black-Scholes options valuation methodology, and the fair value of other stock awards is based upon the market value of the stock on the grant date. The fair value of the awards is expensed over the performance or service period, which generally corresponds to the vesting period, and is recognized as an increase to additional paid-in-capital in stockholders’ equity, and stock-based compensation expense is reflected in other operating expenses in the consolidated statements of income.
Earnings Per Share	Earnings Per Share Basic earnings per share exclude any dilutive effects of any outstanding options. Diluted earnings per share include the dilutive effects assuming outstanding stock options were exercised.
Future Adoption of New Accounting Standards	New Accounting Pronouncements Changes to the general accounting principles are established by the Financial Accounting Standards Board (“FASB”) in the form of accounting standards updates to the FASB Accounting Standards Codification TM . Accounting standards updates not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on the Company’s consolidated financial statements. Description Date of Adoption Effect on the financial statements or other significant matters Standards adopted: Reporting Comprehensive Income This updated guidance requires reclassification from accumulated other comprehensive income to retained earnings for the stranded tax effects resulting from the newly enacted U.S. federal corporate income tax rate. The amount of the reclassification would be the difference between the historical U.S. federal corporate income tax rate and the newly enacted 21 percent tax rate. December 31, 2017 The Company adopted the new guidance by reclassifying certain income tax effects of items within accumulated other comprehensive income to retained earnings as a result of the Tax Cuts and Jobs Act of 2017. The impact of adopting this standard was an increase in accumulated other comprehensive income and a reduction in retained earnings of approximately $156.4 million. The adjustments to the Company’s deferred tax liabilities was a provisional amount as defined in the SEC’s SAB 118, issued in December 2017 to address complexities in completing the calculations resulting from the U.S. Tax Cuts and Jobs Act of 2017. SAB 118 provides guidance on accounting for the effects of the U.S. Tax and Jobs Act of 2017 when the Company’s process is incomplete, and permits a final determination to be made within a measurement period not to exceed one year from the enactment date. During 2018, the Company continued to evaluate and gather additional information to account for the effects of the Tax Cuts and Jobs Act of 2017, including the preparation of and filing of its U.S. tax returns to more precisely compute the pretax deferred tax items and the impact of adopting the new guidance. As part of this process the Company recorded an additional adjustment in 2018 decreasing accumulated other comprehensive income and increasing retained earnings of approximately $2.6 million. Stock Compensation This updated guidance requires excess tax benefits and deficiencies from share-based payment awards be recorded in income tax expense in the income statement. Previously, excess tax benefits and deficiencies were recognized in shareholders’ equity or deferred taxes on the balance sheet depending on the tax situation of the Company. In addition, the updated guidance also changes the accounting for forfeitures and statutory tax withholding requirements, as well as the classification in the statement of cash flows. January 1, 2017 Upon adoption, the Company recognized excess tax benefits of approximately $17.7 million in deferred tax assets that were previously not recognized in a cumulative-effect adjustment increasing retained earnings by $17.7 million. The Company also recorded excess tax benefits of approximately $10.5 million in the provision for income taxes for the year ended December 31, 2017. The number of weighted average diluted shares outstanding were also adjusted to exclude excess tax benefits from the assumed proceeds in the diluted shares calculation resulting in an immaterial increase in the number of dilutive shares outstanding. The Company also elected to continue estimating forfeitures for purposes of recognizing share-based compensation. Other aspects of the adoption of the updated guidance did not have a material impact to the Company’s consolidated financial statements. Financial Instruments - Recognition and Measurement This guidance requires equity investments that are not accounted for under the equity method of accounting to be measured at fair value with changes recognized in net income and also updates certain presentation and disclosure requirements. January 1, 2018 This guidance required a cumulative-effect adjustment for certain items upon adoption. The adoption of the new guidance was not material to the Company's consolidated financial statements. Compensation - Retirement Benefits - Defined Benefit Plans - General This guidance is part of the FASB’s disclosure framework project and eliminates certain disclosure requirements for defined benefit pension and other postretirement plans. Early adoption is permitted. December 31, 2018 This new guidance was applied retrospectively to all periods presented in the year of adoption. The adoption of the new standard was not material to the Company’s consolidated financial statements. Standards not yet adopted: Leases This new standard, based on the principle that entities should recognize assets and liabilities arising from leases, does not significantly change the lessees’ recognition, measurement and presentation of expenses and cash flows from the previous accounting standard. Leases are classified as finance or operating. The new standard’s primary change is the requirement for entities to recognize a lease liability for payments and a right of use asset representing the right to use the leased asset during the term of operating lease arrangements. Lessees are permitted to make an accounting policy election to not recognize the asset and liability for leases with a term of twelve months or less. Lessors’ accounting is largely unchanged from the previous accounting standard. In addition, the new standard expands the disclosure requirements of lease arrangements. Early adoption is permitted. January 1, 2019 This new standard will be adopted by applying the optional transition method and record a right-of use asset and liability on the Company’s balance sheet relating to existing operating leases. The Company does not expect the adoption of the new standard to have a material impact on its results of operations or balance sheet. The Company will recognize a lease liability and right-of-use asset of approximately $55.2 million related to its operating leases upon adoption of the new standard. Derivatives and Hedging This updated guidance improves the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and make certain targeted improvements to simplify the application of the hedge accounting in current GAAP related to the assessment of hedge effectiveness. Early adoption is permitted. January 1, 2019 This new guidance will be adopted by applying a modified retrospective approach to existing hedging relationships as of the date of adoption. The Company does not expect the adoption of the new standard to have a material impact on its results of operations or balance sheet. Upon adoption of the new standard, the Company will record an immaterial adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective and will modify some disclosures. Financial Instruments - Credit Losses This guidance adds to GAAP an impairment model, known as current expected credit loss (“CECL”) model that is based on expected losses rather than incurred losses. For traditional and other receivables, held-to-maturity debt securities, loans and other instruments entities will be required to use the new forward-looking “expected loss” model that generally will result in earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities will measure credit losses similar to what they do today, except the losses will be recognized as allowances rather than reduction to the amortized cost of the securities. Early adoption is permitted. January 1, 2020 This guidance will be adopted through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective (that is, a modified-retrospective approach). The Company is currently evaluating the impact of this amendment on its consolidated financial statements. Fair Value Measurement This guidance is part of the FASB’s disclosure framework project and eliminates certain disclosure requirements for fair value measurement, requires entities to disclose new information and modifies existing disclosure requirements. Early adoption is permitted. January 1, 2020 Certain disclosure changes in the new guidance will be applied prospectively in the year of adoption. The remaining changes in the new guidance will be applied retrospectively to all periods presented in the year of adoption. The Company is currently evaluating the impact of this amendment on its consolidated financial statements. Financial Services - Insurance This guidance significantly changes how insurers account for long-duration insurance contracts. The new guidance will require insurers to review and update, if necessary, the assumptions used to measure insurance liabilities periodically, rather than retain assumptions used at contract inception. The updated guidance also changes the recognition and measurement of deferred acquisition costs (DAC) and created a new category of benefit features called market risk benefits (MRB) that will be measured at fair value. The guidance also significantly expands the disclosure requirements for long-duration contracts. January 1, 2021 The guidance on measuring the liabilities for future policy benefits and DAC will likely be adopted on a modified retrospective basis as of the earliest period presented in the year of adoption. The guidance on MRB will be adopted on a retrospective basis as of the earliest period presented in the year of adoption. The Company is currently evaluating the impact of this amendment on its consolidated financial statements but anticipates the updated guidance will likely have a material impact on the measurement and recognition of its long-duration insurance contracts.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share Basic And Diluted By Common Class [Table Text Block]	The following table sets forth the computation of basic and diluted earnings per share on net income (in thousands, except per share information): 2018 2017 2016 Earnings: Net income (numerator for basic and diluted calculations) $ 715,842 $ 1,822,181 $ 701,443 Shares: Weighted average outstanding shares (denominator for basic calculations) 63,658 64,427 64,274 Equivalent shares from outstanding stock options 1,436 1,326 715 Diluted shares (denominator for diluted calculations) 65,094 65,753 64,989 Earnings per share: Basic $ 11.25 $ 28.28 $ 10.91 Diluted 11.00 27.71 10.79

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments [Abstract]
Available-for-sale Securities [Table Text Block]	The following table provides information relating to investments in fixed maturity securities by sector as of December 31, 2018 (dollars in thousands): December 31, 2018: Amortized Cost Unrealized Gains Unrealized Losses Estimated Fair Value % of Total Other-than- temporary impairments in AOCI Available-for-sale: Corporate $ 24,006,407 $ 530,804 $ 555,092 $ 23,982,119 59.9 % $ — Canadian government 2,768,466 1,126,227 2,308 3,892,385 9.7 — RMBS 1,872,236 22,267 25,282 1,869,221 4.7 — ABS 2,171,254 10,779 32,829 2,149,204 5.4 275 CMBS 1,428,115 9,153 18,234 1,419,034 3.5 — U.S. government 2,233,537 10,204 57,867 2,185,874 5.5 — State and political subdivisions 721,290 39,914 9,010 752,194 1.9 — Other foreign government 3,680,863 109,320 47,868 3,742,315 9.4 — Total fixed maturity securities $ 38,882,168 $ 1,858,668 $ 748,490 $ 39,992,346 100.0 % $ 275 The following table provides information relating to investments in fixed maturity and equity securities by sector as of December 31, 2017 (dollars in thousands): December 31, 2017: Amortized Unrealized Unrealized Estimated % of Total Other-than- Available-for-sale: Corporate $ 21,966,803 $ 1,299,594 $ 55,429 $ 23,210,968 60.9 % $ — Canadian government 2,843,273 1,378,510 1,707 4,220,076 11.1 — RMBS 1,695,126 36,632 11,878 1,719,880 4.5 — ABS 1,634,758 18,798 5,194 1,648,362 4.3 275 CMBS 1,285,594 22,627 4,834 1,303,387 3.4 — U.S. government 1,953,436 12,089 21,933 1,943,592 5.1 — State and political subdivisions 647,727 59,997 4,296 703,428 1.8 — Other foreign government 3,254,695 154,507 8,075 3,401,127 8.9 — Total fixed maturity securities $ 35,281,412 $ 2,982,754 $ 113,346 $ 38,150,820 100.0 % $ 275 Non-redeemable preferred stock $ 41,553 $ 479 $ 2,226 $ 39,806 39.7 % Other equity securities 61,288 479 1,421 60,346 60.3 Total equity securities $ 102,841 $ 958 $ 3,647 $ 100,152 100.0 %
Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block]	The following table includes fixed maturity securities pledged and received as collateral and assets in trust held to satisfy collateral requirements under derivative transactions and certain third-party reinsurance treaties as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Fixed maturity securities pledged as collateral $ 80,891 $ 83,950 $ 72,542 $ 75,622 Fixed maturity securities received as collateral n/a 616,584 n/a 590,417 Assets in trust held to satisfy collateral requirements 20,072,735 20,366,170 15,584,296 16,715,281
Concentration Risk Disclosure [Text Block]	The Company’s exposure to concentrations of credit risk from single issuers greater than 10% of the Company’s stockholders’ equity included securities of the U.S. government and its agencies, as well as the securities disclosed below, as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Fixed maturity securities guaranteed or issued by: Canadian province of Quebec $ 1,091,018 $ 1,757,087 $ 1,119,337 $ 1,917,996 Canadian province of Ontario 913,642 1,187,526 939,837 1,282,944
Investments Classified By Contractual Maturity Date [Table Text Block]	The amortized cost and estimated fair value of fixed maturity securities classified as available-for-sale as of December 31, 2018 are shown by contractual maturity in the table below (dollars in thousands). Actual maturities can differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Asset and mortgage-backed securities are shown separately in the table below, as they are not due at a single maturity date. Amortized Cost Estimated Fair Value Available-for-sale: Due in one year or less $ 1,185,868 $ 1,190,931 Due after one year through five years 8,760,200 8,851,307 Due after five years through ten years 9,060,972 9,149,497 Due after ten years 14,403,523 15,363,152 Asset and mortgage-backed securities 5,471,605 5,437,459 Total $ 38,882,168 $ 39,992,346
Fixed Maturity Holdings Industry Types [Table Text Block]	The tables below show the major industry types of the Company’s corporate fixed maturity holdings as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018: Amortized Cost Estimated Fair Value % of Total Finance $ 8,793,742 $ 8,730,568 36.3 % Industrial 12,336,857 12,342,111 51.6 Utility 2,875,808 2,909,440 12.1 Total $ 24,006,407 $ 23,982,119 100.0 % December 31, 2017: Amortized Cost Estimated Fair Value % of Total Finance $ 7,977,885 $ 8,362,774 36.1 % Industrial 11,535,166 12,199,333 52.5 Utility 2,453,752 2,648,861 11.4 Total $ 21,966,803 $ 23,210,968 100.0 %
Roll Forward Of Cumulative Credit Loss Component Of Otti Income Loss [Table Text Block]	The following table sets forth the amount of pre-tax credit loss impairments on fixed maturity securities held by the Company as of the dates indicated, for which a portion of the OTTI loss was recognized in AOCI, and the corresponding changes in such amounts (dollars in thousands): 2018 2017 2016 Balance, beginning of period $ 3,677 $ 6,013 $ 7,284 Additional impairments - credit loss OTTI recognized on securities previously impaired — — 231 Credit loss impairments previously recognized on securities impaired to fair value during the period — (2,336 ) — Credit loss previously recognized on securities that matured, paid down, prepaid or were sold during the period — — (1,502 ) Balance, end of period $ 3,677 $ 3,677 $ 6,013
Investments In Debt And Equity Securities Gross Unrealized Losses Disclosures [Table Text Block]	The following table presents the total gross unrealized losses for the 3,109 fixed maturity securities as of December 31, 2018, where the estimated fair value had declined and remained below amortized cost by the indicated amount (dollars in thousands): 2018 Gross Unrealized Losses % of Total Less than 20% $ 721,015 96.3 % 20% or more for less than six months 21,336 2.9 20% or more for six months or greater 6,139 0.8 Total $ 748,490 100.0 % The following table presents the total gross unrealized losses for the 1,116 fixed maturity and equity securities as of December 31, 2017, where the estimated fair value had declined and remained below amortized cost by the indicated amount (dollars in thousands): 2017 Gross Unrealized Losses % of Total Less than 20% $ 113,466 97.0 % 20% or more for less than six months 689 0.6 20% or more for six months or greater 2,838 2.4 Total $ 116,993 100.0 %
Fair Value And Investments In Debt And Equity Securities Disclosures [Table Text Block]	The following table presents the estimated fair values and gross unrealized losses, including other-than-temporary impairment losses reported in AOCI, for 3,109 fixed maturity securities that have estimated fair values below amortized cost as of December 31, 2018 (dollars in thousands). These investments are presented by class and grade of security, as well as the length of time the related fair value has remained below amortized cost. Less than 12 months 12 months or greater Total December 31, 2018: Estimated Fair Value Gross Unrealized Losses Estimated Gross Estimated Gross Investment grade securities: Corporate $ 8,505,371 $ 302,604 $ 3,611,266 $ 195,082 $ 12,116,637 $ 497,686 Canadian government 25,169 419 131,806 1,612 156,975 2,031 RMBS 269,558 2,488 836,741 22,760 1,106,299 25,248 ABS 1,102,677 24,271 381,609 8,523 1,484,286 32,794 CMBS 384,259 4,304 414,719 13,930 798,978 18,234 U.S. government 8,616 80 1,086,694 57,787 1,095,310 57,867 State and political subdivisions 103,504 1,538 157,330 7,472 260,834 9,010 Other foreign government 789,859 24,509 472,934 17,446 1,262,793 41,955 Total investment grade securities 11,189,013 360,213 7,093,099 324,612 18,282,112 684,825 Below investment grade securities: Corporate 755,679 42,760 122,559 14,646 878,238 57,406 Canadian government 443 34 1,770 243 2,213 277 RMBS — — 1,026 34 1,026 34 ABS — — 1,063 35 1,063 35 Other foreign government 128,725 5,574 7,479 339 136,204 5,913 Total below investment grade securities 884,847 48,368 133,897 15,297 1,018,744 63,665 Total fixed maturity securities $ 12,073,860 $ 408,581 $ 7,226,996 $ 339,909 $ 19,300,856 $ 748,490 The following table presents the estimated fair values and gross unrealized losses, including other-than-temporary impairment losses reported in AOCI, for 1,116 fixed maturity and equity securities that have estimated fair values below amortized cost as of December 31, 2017 (dollars in thousands): Less than 12 months 12 months or greater Total December 31, 2017: Estimated Gross Estimated Gross Estimated Gross Investment grade securities: Corporate $ 1,886,212 $ 17,099 $ 1,009,750 $ 28,080 $ 2,895,962 $ 45,179 Canadian government 18,688 91 111,560 1,596 130,248 1,687 RMBS 566,699 5,852 224,439 6,004 791,138 11,856 ABS 434,274 2,707 168,524 2,434 602,798 5,141 CMBS 220,401 1,914 103,269 2,920 323,670 4,834 U.S. government 800,298 6,177 767,197 15,756 1,567,495 21,933 State and political subdivisions 43,510 242 68,666 4,054 112,176 4,296 Other foreign government 369,717 2,707 191,265 4,704 560,982 7,411 Total investment grade securities 4,339,799 36,789 2,644,670 65,548 6,984,469 102,337 Below investment grade securities: Corporate 194,879 3,317 75,731 6,933 270,610 10,250 Canadian government 1,995 20 — — 1,995 20 RMBS — — 1,369 22 1,369 22 ABS — — 1,489 53 1,489 53 Other foreign government 28,600 113 15,134 551 43,734 664 Total below investment grade securities 225,474 3,450 93,723 7,559 319,197 11,009 Total fixed maturity securities $ 4,565,273 $ 40,239 $ 2,738,393 $ 73,107 $ 7,303,666 $ 113,346 Non-redeemable preferred stock $ 82 $ 1 $ 26,471 $ 2,225 $ 26,553 $ 2,226 Other equity securities 5,820 1,023 47,251 398 53,071 1,421 Total equity securities $ 5,902 $ 1,024 $ 73,722 $ 2,623 $ 79,624 $ 3,647
Investment Income [Table Text Block]	Major categories of investment income, net of related expenses, consist of the following (dollars in thousands): 2018 2017 2016 Fixed maturity securities available-for-sale $ 1,528,086 $ 1,401,585 $ 1,285,406 Equity securities 4,343 4,445 12,513 Mortgage loans on real estate 214,387 197,755 168,582 Policy loans 59,332 60,617 63,837 Funds withheld at interest 309,977 457,774 368,728 Short-term investments and cash and cash equivalents 14,349 7,171 8,051 Other invested assets 98,557 106,015 76,858 Investment income 2,229,031 2,235,362 1,983,975 Investment expense (90,506 ) (80,711 ) (72,089 ) Investment income, net of related expenses $ 2,138,525 $ 2,154,651 $ 1,911,886
Gain (Loss) on Securities [Table Text Block]	Investment related gains (losses), net, consist of the following (dollars in thousands): 2018 2017 2016 Fixed maturity securities available-for-sale: Other-than-temporary impairment losses $ (28,494 ) $ (42,639 ) $ (38,805 ) Portion of loss recognized in accumulated other comprehensive income — — 74 Gain on investment activity 65,211 110,546 145,172 Loss on investment activity (158,870 ) (37,328 ) (47,094 ) Equity securities: Other-than-temporary impairment losses — (1,202 ) — Gain on investment activity 4,429 23 9,198 Loss on investment activity (1,937 ) (4,351 ) (2,871 ) Change in unrealized gains (losses) recognized in earnings (23,184 ) — — Other impairment losses and change in mortgage loan provision (11,919 ) (9,497 ) (11,006 ) Derivatives and other, net (15,324 ) 152,328 39,527 Total investment related gains (losses), net $ (170,088 ) $ 167,880 $ 94,195
Schedule of Repurchase Agreements [Table Text Block]	The following table includes the amount of borrowed securities, securities lent and securities collateral received as part of the securities lending program, repurchased/reverse repurchased securities pledged and received and cash received as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Borrowed securities $ 335,781 $ 366,663 $ 358,875 $ 377,820 Securities lending: Securities loaned 101,981 102,618 117,246 121,551 Securities received n/a 112,000 n/a 128,000 Repurchase program/reverse repurchase program: Securities pledged 554,806 554,589 413,819 428,344 Securities received n/a 530,932 n/a 417,550
Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets [Table Text Block]	The following tables present information on the Company’s securities lending and repurchase transactions as of December 31, 2018 and 2017 , respectively (dollars in thousands). Collateral associated with certain borrowed securities is not included within the tables as the collateral pledged to each counterparty is the right to reinsurance treaty cash flows. December 31, 2018 Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total Securities lending transaction: Corporate $ — $ — $ — $ 102,618 $ 102,618 Total — — — 102,618 102,618 Repurchase transactions: Corporate — — — 254,151 254,151 U.S. government — — — 221,572 221,572 Foreign government — — — 78,866 78,866 Total — — — 554,589 554,589 Total transactions $ — $ — $ — $ 657,207 $ 657,207 Gross amount of recognized liabilities for securities lending and repurchase transactions in preceding table $ 671,492 Amounts related to agreements not included in offsetting disclosure $ 14,285 December 31, 2017 Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total Securities lending transaction: Corporate $ — $ — $ — $ 121,551 $ 121,551 Total — — — 121,551 121,551 Repurchase transactions: Corporate — — 312 184,334 $ 184,646 U.S. government — — — 220,765 220,765 Foreign government — — — 21,802 21,802 Other 1,131 — — — 1,131 Total 1,131 — 312 426,901 428,344 Total transactions $ 1,131 $ — $ 312 $ 548,452 $ 549,895 Gross amount of recognized liabilities for repurchase transactions in preceding table $ 576,786 Amounts related to agreements not included in offsetting disclosure $ 26,891
Disclosure Of Real Estate Holdings By Property Type [Table Text Block]	The recorded investment in mortgage loans on real estate presented below is gross of unamortized deferred loan origination fees and expenses, and valuation allowances. The distribution of mortgage loans by property type is as follows as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Carrying Value Percentage of Total Carrying Value Percentage of Total Property type: Office building $ 1,725,748 34.6 % $ 1,487,392 33.6 % Retail 1,432,394 28.7 1,270,676 28.8 Industrial 961,924 19.3 938,612 21.3 Apartment 571,291 11.5 510,052 11.6 Other commercial 291,997 5.9 206,439 4.7 Recorded investment $ 4,983,354 100.0 % $ 4,413,171 100.0 % Unamortized balance of loan origination fees and expenses (5,770 ) (3,254 ) Valuation allowances (11,286 ) (9,384 ) Total mortgage loans on real estate $ 4,966,298 $ 4,400,533
Disclosure of Real Estate Holdings Classified By Contractual Maturity Date [Table Text Block]	The maturities of the mortgage loans as of December 31, 2018 and 2017 are as follows (dollars in thousands): 2018 2017 Recorded Investment % of Total Recorded Investment % of Total Due within five years $ 1,425,598 28.6 % $ 1,091,066 24.8 % Due after five years through ten years 2,686,264 53.9 2,516,872 57.0 Due after ten years 871,492 17.5 805,233 18.2 Total $ 4,983,354 100.0 % $ 4,413,171 100.0 %
Financing Receivable Credit Quality Indicators [Table Text Block]	The following tables set forth certain key credit quality indicators of the Company’s recorded investment in mortgage loans as of December 31, 2018 and 2017 (dollars in thousands): Recorded Investment Debt Service Ratios Construction loans >1.20x 1.00x - 1.20x <1.00x Total % of Total December 31, 2018: Loan-to-Value Ratio 0% - 59.99% $ 2,410,556 $ 61,246 $ 38,177 $ 13,691 $ 2,523,670 50.6 % 60% - 69.99% 1,618,374 73,908 38,120 18,929 1,749,331 35.1 70% - 79.99% 414,269 48,438 54,440 — 517,147 10.4 Greater than 80% 117,978 49,668 25,560 — 193,206 3.9 Total $ 4,561,177 $ 233,260 $ 156,297 $ 32,620 $ 4,983,354 100.0 % Recorded Investment Debt Service Ratios Construction loans >1.20x 1.00x - 1.20x <1.00x Total % of Total December 31, 2017: Loan-to-Value Ratio 0% - 59.99% $ 2,148,428 $ 53,979 $ 3,801 $ — $ 2,206,208 50.0 % 60% - 69.99% 1,517,029 47,128 43,921 — 1,608,078 36.4 70% - 79.99% 396,446 19,461 15,367 — 431,274 9.8 Greater than 80% 120,850 30,713 6,362 9,686 167,611 3.8 Total $ 4,182,753 $ 151,281 $ 69,451 $ 9,686 $ 4,413,171 100.0 %
Past Due Financing Receivables [Table Text Block]	The age analysis of the Company’s past due recorded investments in mortgage loans as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 31-60 days past due $ — $ 17,100 61-90 days past due — 2,056 Total past due — 19,156 Current 4,983,354 4,394,015 Total $ 4,983,354 $ 4,413,171
Recorded Investment And Allowance For Credit Losses [Table Text Block]	The following table presents the recorded investment in mortgage loans, by method of measuring impairment, and the related valuation allowances, as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Mortgage loans: Individually measured for impairment $ 30,635 $ 5,858 Collectively measured for impairment 4,952,719 4,407,313 Recorded investment $ 4,983,354 $ 4,413,171 Valuation allowances: Individually measured for impairment $ — $ — Collectively measured for impairment 11,286 9,384 Total valuation allowances $ 11,286 $ 9,384
Allowance For Loan And Lease Losses Provision For Loss Net [Table Text Block]	Information regarding the Company’s loan valuation allowances for mortgage loans as of December 31, 2018, 2017 and 2016 are as follows (dollars in thousands): 2018 2017 2016 Balance, beginning of period $ 9,384 $ 7,685 $ 6,813 Provision 1,918 1,691 872 Translation adjustment (16 ) 8 — Balance, end of period $ 11,286 $ 9,384 $ 7,685
Impaired Financing Receivables [Table Text Block]	Information regarding the portion of the Company’s mortgage loans that were impaired as of December 31, 2018 and 2017 is as follows (dollars in thousands): Unpaid Principal Balance Recorded Investment Related Allowance Carrying Value December 31, 2018: Impaired mortgage loans with no valuation allowance recorded $ 30,660 $ 30,635 $ — $ 30,635 Impaired mortgage loans with valuation allowance recorded — — — — Total impaired mortgage loans $ 30,660 $ 30,635 $ — $ 30,635 December 31, 2017: Impaired mortgage loans with no valuation allowance recorded $ 6,427 $ 5,858 $ — $ 5,858 Impaired mortgage loans with valuation allowance recorded — — — — Total impaired mortgage loans $ 6,427 $ 5,858 $ — $ 5,858 The Company’s average investment balance of impaired mortgage loans and the related interest income are reflected in the table below for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): 2018 2017 2016 Average Investment (1) Interest Income Average Investment (1) Interest Income Average Investment (1) Interest Income Impaired mortgage loans with no valuation allowance recorded $ 24,240 $ 1,129 $ 3,621 $ 186 $ 2,249 $ 142 Impaired mortgage loans with valuation allowance recorded — — — — — — Total $ 24,240 $ 1,129 $ 3,621 $ 186 $ 2,249 $ 142 (1) Average recorded investment represents the average loan balances as of the beginning of period and all subsequent quarterly end of period balances.
Schedule of Other Assets [Table Text Block]	Other invested assets represented approximately 3.5% and 2.9% of the Company’s total investments as of December 31, 2018 and 2017 , respectively. Carrying values of these assets as of December 31, 2018 and 2017 are as follows (dollars in thousands): 2018 2017 Limited partnership interests and real estate joint ventures $ 965,094 $ 781,124 Equity release mortgages 475,905 219,940 Derivatives 180,699 137,613 FVO contractholder-directed unit-linked investments 197,770 218,541 Other 95,829 148,114 Total other invested assets $ 1,915,297 $ 1,505,332

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table presents the notional amounts and gross fair value of derivative instruments prior to taking into account the netting effects of master netting agreements as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018 December 31, 2017 Primary Underlying Risk Notional Carrying Value/Fair Value Notional Carrying Value/Fair Value Amount Assets Liabilities Amount Assets Liabilities Derivatives not designated as hedging instruments: Interest rate swaps Interest rate $ 1,040,588 $ 47,652 $ 961 $ 996,204 $ 59,809 $ 2,372 Financial futures Equity 325,620 — — 412,438 — — Foreign currency swaps Foreign currency 149,698 504 4,659 — — — Foreign currency forwards Foreign currency 25,000 — 234 6,030 — 28 CPI swaps CPI 385,580 — 11,384 221,932 — 2,160 Credit default swaps Credit 1,338,300 6,003 1,166 961,200 8,319 1,651 Equity options Equity 439,158 42,836 — 632,251 23,271 — Longevity swaps Longevity 917,360 47,789 — 960,400 40,659 — Mortality swaps Mortality 25,000 — 369 — — 1,683 Synthetic GICs Interest rate 13,397,729 — — 10,052,576 — — Embedded derivatives in: Modco or funds withheld arrangements — 109,597 — — 122,194 — Indexed annuity products — — 776,940 — — 861,758 Variable annuity products — — 167,925 — — 152,470 Total non-hedging derivatives 18,044,033 254,381 963,638 14,243,031 254,252 1,022,122 Derivatives designated as hedging instruments: Interest rate swaps Foreign currency/Interest rate 435,000 — 27,257 435,000 — 20,389 Foreign currency swaps Foreign currency 494,461 51,311 — 672,921 65,207 8,496 Foreign currency forwards Foreign currency 911,197 50,974 — 553,175 1,265 7,720 Total hedging derivatives 1,840,658 102,285 27,257 1,661,096 66,472 36,605 Total derivatives $ 19,884,691 $ 356,666 $ 990,895 $ 15,904,127 $ 320,724 $ 1,058,727
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]	The gain or loss on the hedged item attributable to a change in foreign currency and the offsetting gain or loss on the related foreign currency swaps as of December 31, 2018, 2017 and 2016 were (dollars in thousands): Type of Fair Value Hedge Hedged Item Gains (Losses) Recognized for Derivatives (1) Gains (Losses) Recognized for Hedged Items (1) For the Year Ended December 31, 2018: Foreign currency swaps Foreign-denominated fixed maturity securities $ (11,164 ) $ 12,446 For the Year Ended December 31, 2017: Foreign currency swaps Foreign-denominated fixed maturity securities $ 9,456 $ (9,456 ) For the Year Ended December 31, 2016: Foreign currency swaps Foreign-denominated fixed maturity securities $ (1,700 ) $ 1,700 (1) The net amount represents the ineffective portion of the fair value hedges.
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents the components of AOCI, before income tax, and the consolidated income statement classification where the gain or loss is recognized related to cash flow hedges for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): Amounts Included in AOCI Balance December 31, 2015 $ (29,397 ) Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges 27,110 Amounts reclassified to investment related (gains) losses, net 278 Amounts reclassified to investment income (487 ) Balance December 31, 2016 (2,496 ) Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges 6,316 Amounts reclassified to investment related (gains) losses, net (775 ) Amounts reclassified to investment income (505 ) Amounts reclassified to interest expense 79 Balance December 31, 2017 2,619 Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges 6,644 Amounts reclassified to investment income (292 ) Amounts reclassified to interest expense (183 ) Balance December 31, 2018 $ 8,788
Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]	The following table presents the effective portion of derivatives in cash flow hedging relationships on the consolidated statements of income and the consolidated statements of stockholders’ equity for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): Effective Portion Derivative Type Gains (Losses) Deferred in OCI Gains (Losses) Reclassified into Income from OCI For the year ended December 31, 2018: Investment Related Gains (Losses) Investment Income Interest Expense Interest rate $ 12,886 $ — $ — $ 183 Foreign currency/Interest rate (6,242 ) — 292 — Total $ 6,644 $ — $ 292 $ 183 For the year ended December 31, 2017: Interest rate $ (5,649 ) $ — $ — $ (79 ) Foreign currency/Interest rate 11,955 — 380 — Forward bond purchase commitments 10 775 125 — Total $ 6,316 $ 775 $ 505 $ (79 ) For the year ended December 31, 2016: Interest rate $ 27,901 $ — $ — $ — Foreign currency/Interest rate (791 ) — 510 — Forward bond purchase commitments — (278 ) (23 ) — Total $ 27,110 $ (278 ) $ 487 $ —
Schedule of Net Investment Hedges, Statements of Financial Performance and Financial Position, Location [Table Text Block]	The following table illustrates the Company’s net investments in foreign operations (“NIFO”) hedges for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): Derivative Gains (Losses) Deferred in AOCI For the year ended Type of NIFO Hedge (1) (2) 2018 2017 2016 Foreign currency swaps $ 31,431 $ (37,567 ) $ (10,234 ) Foreign currency forwards 55,913 (10,386 ) — (1) There were no sales or substantial liquidations of net investments in foreign operations that would have required the reclassification of gains or losses from accumulated other comprehensive income (loss) into investment income during the periods presented. (2) There was no ineffectiveness recognized for the Company’s hedges of net investments in foreign operations.
Derivative Instruments Gain Loss By Income Statement Location [Table Text Block]	A summary of the effect of non-hedging derivatives, including embedded derivatives, on the Company’s consolidated statements of income for the years ended December 31, 2018, 2017 and 2016 is as follows (dollars in thousands): Gains (Losses) for the Years Ended December 31, Type of Non-hedging Derivative Income Statement Location of Gains (Losses) 2018 2017 2016 Interest rate swaps Investment related gains (losses), net $ (21,314 ) $ 11,278 $ 7,649 Financial futures Investment related gains (losses), net 21,200 (36,160 ) (40,242 ) Foreign currency swaps Investment related gains (losses), net (3,695 ) — — Foreign currency forwards Investment related gains (losses), net (234 ) 591 1,630 Consumer price index swaps Investment related gains (losses), net (10,047 ) (2,078 ) (401 ) Credit default swaps Investment related gains (losses), net (2,150 ) 18,118 18,100 Equity options Investment related gains (losses), net 7,315 (42,953 ) (28,270 ) Longevity swaps Other revenues 9,215 9,358 13,095 Mortality swaps Other revenues (386 ) (921 ) (172 ) Subtotal (96 ) (42,767 ) (28,611 ) Embedded derivatives in: Modco or funds withheld arrangements Investment related gains (losses), net (12,597 ) 144,723 54,169 Indexed annuity products Interest credited 27,591 (80,062 ) 10,708 Variable annuity products Investment related gains (losses), net (15,455 ) 32,166 7,835 Total non-hedging derivatives $ (557 ) $ 54,060 $ 44,101
Disclosure Of Credit Derivatives [Table Text Block]	The following table presents the estimated fair value, maximum amount of future payments and weighted average years to maturity of credit default swaps sold by the Company as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Rating Agency Designation of Referenced Credit Obligations (1) Estimated Fair Value of Credit Default Swaps Maximum Amount of Future Payments under Credit Default Swaps (2) Weighted Average Years to Maturity (3) Estimated Fair Maximum (2) Weighted (3) AAA/AA+/AA/AA-/A+/A/A- Single name credit default swaps $ 1,953 $ 152,000 2.2 $ 3,128 $ 162,000 2.9 Subtotal 1,953 152,000 2.2 3,128 162,000 2.9 BBB+/BBB/BBB- Single name credit default swaps 2,930 353,700 2.2 4,469 361,700 2.9 Credit default swaps referencing indices (76 ) 817,600 6.4 (55 ) 422,600 4.0 Subtotal 2,854 1,171,300 5.1 4,414 784,300 3.5 BB+/BB/BB- Single name credit default swaps 30 15,000 0.7 30 5,000 1.5 Subtotal 30 15,000 0.7 30 5,000 1.5 Total $ 4,837 $ 1,338,300 4.7 $ 7,572 $ 951,300 3.4 (1) The rating agency designations are based on ratings from Standard and Poor’s (“S&P”). (2) Assumes the value of the referenced credit obligations is zero. (3) The weighted average years to maturity of the credit default swaps is calculated based on weighted average notional amounts.
Offsetting Assets [Table Text Block]	The following table provides information relating to the netting of the Company’s derivative instruments as of December 31, 2018 and December 31, 2017 (dollars in thousands): Gross Amounts Not Offset in the Balance Sheet Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts Presented in the Balance Sheet Financial Instruments (1) Cash Collateral Pledged/ Received Net Amount December 31, 2018: Derivative assets $ 247,069 $ (18,581 ) $ 228,488 $ — $ (235,611 ) $ (7,123 ) Derivative liabilities 46,030 (18,581 ) 27,449 (71,376 ) (24,080 ) (68,007 ) December 31, 2017: Derivative assets $ 198,530 $ (20,258 ) $ 178,272 $ (862 ) $ (185,900 ) $ (8,490 ) Derivative liabilities 44,499 (20,258 ) 24,241 (58,156 ) (22,221 ) (56,136 )
Offsetting Liabilities [Table Text Block]	The following table provides information relating to the netting of the Company’s derivative instruments as of December 31, 2018 and December 31, 2017 (dollars in thousands): Gross Amounts Not Offset in the Balance Sheet Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts Presented in the Balance Sheet Financial Instruments (1) Cash Collateral Pledged/ Received Net Amount December 31, 2018: Derivative assets $ 247,069 $ (18,581 ) $ 228,488 $ — $ (235,611 ) $ (7,123 ) Derivative liabilities 46,030 (18,581 ) 27,449 (71,376 ) (24,080 ) (68,007 ) December 31, 2017: Derivative assets $ 198,530 $ (20,258 ) $ 178,272 $ (862 ) $ (185,900 ) $ (8,490 ) Derivative liabilities 44,499 (20,258 ) 24,241 (58,156 ) (22,221 ) (56,136 )

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	Assets and liabilities measured at fair value on a recurring basis as of December 31, 2018 and 2017 are summarized below (dollars in thousands): December 31, 2018: Fair Value Measurements Using: Total Level 1 Level 2 Level 3 Assets: Fixed maturity securities – available-for-sale: Corporate $ 23,982,119 $ — $ 22,651,194 $ 1,330,925 Canadian government 3,892,385 — 3,364,261 528,124 RMBS 1,869,221 — 1,862,366 6,855 ABS 2,149,204 — 2,053,632 95,572 CMBS 1,419,034 — 1,419,012 22 U.S. government 2,185,874 2,067,529 100,320 18,025 State and political subdivisions 752,194 — 741,992 10,202 Other foreign government 3,742,315 — 3,737,309 5,006 Total fixed maturity securities – available-for-sale 39,992,346 2,067,529 35,930,086 1,994,731 Equity securities 82,197 48,737 — 33,460 Funds withheld at interest – embedded derivatives 109,597 — — 109,597 Cash equivalents 485,167 473,509 11,658 — Short-term investments 105,991 4,989 98,774 2,228 Other invested assets: Derivatives: Interest rate swaps 37,976 — 37,976 — Foreign currency forwards 50,740 — 50,740 — Credit default swaps 4,466 — 4,466 — Equity options 36,206 — 36,206 — Foreign currency swaps 51,311 — 51,311 — FVO contractholder-directed unit-linked investments 197,770 196,781 989 — Total other invested assets 378,469 196,781 181,688 — Other assets - longevity swaps 47,789 — — 47,789 Total $ 41,201,556 $ 2,791,545 $ 36,222,206 $ 2,187,805 Liabilities: Interest-sensitive contract liabilities – embedded derivatives $ 944,865 $ — $ — $ 944,865 Other liabilities: Derivatives: Interest rate swaps 18,542 — 18,542 — Foreign currency swaps - non-hedged 4,155 — 4,155 — CPI swaps 11,384 — 11,384 — Credit default swaps (371 ) — (371 ) — Equity options (6,630 ) — (6,630 ) — Mortality swaps 369 — — 369 Total $ 972,314 $ — $ 27,080 $ 945,234 December 31, 2017: Fair Value Measurements Using: Total Level 1 Level 2 Level 3 Assets: Fixed maturity securities – available-for-sale: Corporate $ 23,210,968 $ — $ 21,873,696 $ 1,337,272 Canadian government 4,220,076 — 3,626,134 593,942 RMBS 1,719,880 — 1,611,998 107,882 ABS 1,648,362 — 1,524,888 123,474 CMBS 1,303,387 — 1,300,153 3,234 U.S. government 1,943,592 1,818,006 103,075 22,511 State and political subdivisions 703,428 — 662,225 41,203 Other foreign government 3,401,127 — 3,396,035 5,092 Total fixed maturity securities – available-for-sale 38,150,820 1,818,006 34,098,204 2,234,610 Equity securities: Non-redeemable preferred stock 39,806 39,806 — — Other equity securities 60,346 60,346 — — Funds withheld at interest – embedded derivatives 122,194 — — 122,194 Cash equivalents 356,788 354,071 2,717 — Short-term investments 50,746 — 47,650 3,096 Other invested assets: Derivatives: Interest rate swaps 51,359 — 51,359 — Foreign currency forwards 730 — 730 — CPI swaps (221 ) — (221 ) — Credit default swaps 5,908 — 5,908 — Equity options 16,932 — 16,932 — Foreign currency swaps 62,905 — 62,905 — FVO contractholder-directed unit-linked investments 218,541 217,618 923 — Total other invested assets 356,154 217,618 138,536 — Other assets - longevity swaps 40,659 — — 40,659 Total $ 39,177,513 $ 2,489,847 $ 34,287,107 $ 2,400,559 Liabilities: Interest-sensitive contract liabilities – embedded derivatives $ 1,014,228 $ — $ — $ 1,014,228 Other liabilities: Derivatives: Interest rate swaps 14,311 — 14,311 — Foreign currency forwards 7,213 — 7,213 — CPI swaps 1,939 — 1,939 — Credit default swaps (760 ) — (760 ) — Equity options (6,339 ) — (6,339 ) — Foreign currency swaps 6,194 — 6,194 — Mortality swaps 1,683 — — 1,683 Total $ 1,038,469 $ — $ 22,558 $ 1,015,911
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Level Transfers [Table Text Block]	There were no transfers between Level 1 and Level 2 for the year ended December 31, 2018. The following table presents the transfers between Level 1 and Level 2 during the year ended December 31, 2017 (dollars in thousands): 2017 Transfers from Level 1 to Level 2 Transfers from Level 2 to Level 1 Fixed maturity securities - available-for-sale: Corporate $ 596,809 $ 88,674 Other foreign government 317,640 —
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]	The following table presents quantitative information about significant unobservable inputs used in Level 3 fair value measurements that are developed internally by the Company as of December 31, 2018 and 2017 (dollars in thousands): Fair Value Valuation Unobservable Range (Weighted Average) Assets: 2018 2017 Technique Input 2018 2017 Corporate $ 642,647 $ 173,579 Market comparable securities Liquidity premium 0-5% (1%) 0-2% (1%) EBITDA Multiple 5.9x-7.5x (6.5x) — ABS 77,842 — Market comparable securities Liquidity premium 0-1% (1%) — U.S. government 18,025 22,511 Market comparable securities Liquidity premium 0-1% (1%) 0-1% (1%) State and political subdivisions — 4,616 Market comparable securities Liquidity premium — 1% Other foreign government 5,006 — Market comparable securities Liquidity premium 1% — Equity securities 25,007 — Market comparable securities Liquidity premium 4% — EBITDA Multiple 6.9x-12.3x (7.9x) — Funds withheld at interest- embedded derivatives 109,597 122,194 Total return swap Mortality 0-100% (2%) 0-100% (2%) Lapse 0-35% (10%) 0-35% (9%) Withdrawal 0-5% (3%) 0-5% (3%) CVA 0-5% (1%) 0-5% (1%) Crediting rate 2-4% (2%) 2-4% (2%) Longevity swaps 47,789 40,659 Discounted cash flow Mortality 0-100% (2%) 0-100% (2%) Mortality improvement (10%)-10% (3%) (10%)-10% (3%) Liabilities: Interest-sensitive contract liabilities- embedded derivatives- indexed annuities 776,940 861,758 Discounted cash flow Mortality 0-100% (2%) 0-100% (2%) Lapse 0-35% (10%) 0-35% (9%) Withdrawal 0-5% (3%) 0-5% (3%) Option budget projection 2-4% (2%) 2-4% (2%) Interest-sensitive contract liabilities- embedded derivatives- variable annuities 167,925 152,470 Discounted cash flow Mortality 0-100% (1%) 0-100% (1%) Lapse 0-25% (5%) 0-25% (5%) Withdrawal 0-7% (5%) 0-7% (3%) CVA 0-5% (1%) 0-5% (1%) Long-term volatility 0-27% (13%) 0-27% (8%) Mortality swaps 369 1,683 Discounted cash flow Mortality 0-100% (1%) 0-100% (1%)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	For the year ended December 31, 2018: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,337,272 $ 593,942 $ 107,882 $ 123,474 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (1,045 ) 13,965 (129 ) 224 Investment related gains (losses), net (4,651 ) — 312 1,910 Included in other comprehensive income (32,983 ) (79,783 ) (1,786 ) (1,344 ) Purchases (1) 509,134 — 52,279 42,120 Sales (1) (106,005 ) — (4,961 ) (462 ) Settlements (1) (273,898 ) — (4,633 ) (57,476 ) Transfers into Level 3 9,948 — 3,031 73,289 Transfers out of Level 3 (106,847 ) — (145,140 ) (86,163 ) Fair value, end of period $ 1,330,925 $ 528,124 $ 6,855 $ 95,572 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (998 ) $ 13,965 $ 3 $ 209 Investment related gains (losses), net (6,320 ) — — — For the year ended December 31, 2018 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 3,234 $ 22,511 $ 41,203 $ 5,092 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses — (423 ) 9 — Investment related gains (losses), net 1 (208 ) — — Included in other comprehensive income (65 ) (436 ) 66 (86 ) Purchases (1) — 418 — — Sales (1) (1,751 ) — — — Settlements (1) (5 ) (3,837 ) (494 ) — Transfers into Level 3 1,752 — 9,859 — Transfers out of Level 3 (3,144 ) — (40,441 ) — Fair value, end of period $ 22 $ 18,025 $ 10,202 $ 5,006 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ — $ (417 ) $ 8 $ — For the year ended December 31, 2018 (continued): Equity securities Funds withheld at interest-embedded derivatives Short-term investments Other assets - longevity swaps Interest-sensitive contract Other liabilities - mortality swaps Fair value, beginning of period $ — $ 122,194 $ 3,096 $ 40,659 $ (1,014,228 ) $ (1,683 ) Total gains/losses (realized/unrealized) Included in earnings, net: Investment related gains (losses), net (12,600 ) (12,597 ) — — (15,455 ) — Interest credited — — — — 27,590 — Included in other comprehensive income — — 1 (2,085 ) — — Other revenues — — — 9,215 — (386 ) Purchases (1) 13,962 — 2,624 — (19,182 ) — Sales (1) (6,759 ) — (250 ) — — — Settlements (1) (48 ) — (461 ) — 76,410 1,700 Transfers into Level 3 38,905 — — — — — Transfers out of Level 3 — — (2,782 ) — — — Fair value, end of period $ 33,460 $ 109,597 $ 2,228 $ 47,789 $ (944,865 ) $ (369 ) Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment related gains (losses), net $ (15,992 ) $ (12,597 ) $ — $ — $ (22,393 ) $ — Other revenues — — — 9,215 — (386 ) Interest credited — — — — (48,819 ) — For the year ended December 31, 2017: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,272,253 $ 475,965 $ 160,291 $ 219,280 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (1,429 ) 13,180 (346 ) 1,776 Investment related gains (losses), net 4,991 — 729 245 Included in other comprehensive income (6,719 ) 104,797 2,341 7,044 Purchases (1) 408,995 — 76,792 45,215 Sales (1) (89,248 ) — (28,043 ) — Settlements (1) (285,958 ) — (18,988 ) (87,328 ) Transfers into Level 3 47,360 — 9,100 85,152 Transfers out of Level 3 (12,973 ) — (93,994 ) (147,910 ) Fair value, end of period $ 1,337,272 $ 593,942 $ 107,882 $ 123,474 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (1,457 ) $ 13,180 $ (196 ) $ 669 Investment related gains (losses), net (5,389 ) — (346 ) — For the year ended December 31, 2017 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 21,145 $ 24,488 $ 41,666 $ 12,869 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses 709 (461 ) (55 ) (1 ) Investment related gains (losses), net (595 ) — — — Included in other comprehensive income (71 ) 19 (15 ) (252 ) Purchases (1) — 465 — 496 Sales (1) (3,720 ) — — — Settlements (1) (5,404 ) (2,000 ) (843 ) (672 ) Transfers into Level 3 1,302 — 7,294 — Transfers out of Level 3 (10,132 ) — (6,844 ) (7,348 ) Fair value, end of period $ 3,234 $ 22,511 $ 41,203 $ 5,092 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ — $ (461 ) $ (54 ) $ (1 ) For the year ended December 31, 2017 (continued): Short-term investments Funds withheld at interest-embedded derivatives Other assets - longevity swaps Interest-sensitive contract Other liabilities - mortality swaps Fair value, beginning of period $ 3,346 $ (22,529 ) $ 26,958 $ (990,308 ) $ (2,462 ) Total gains/losses (realized/unrealized) Included in earnings, net: Investment related gains (losses), net — 144,723 — 32,166 — Interest credited — — — (80,062 ) — Included in other comprehensive income 11 — 4,343 — — Other revenues — — 9,358 — (921 ) Purchases (1) 3,703 — — (55,237 ) — Settlements (1) (335 ) — — 79,213 1,700 Transfers out of Level 3 (3,629 ) — — — — Fair value, end of period $ 3,096 $ 122,194 $ 40,659 $ (1,014,228 ) $ (1,683 ) Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment related gains (losses), net $ — $ 144,723 $ — $ 23,472 $ — Other revenues — — 9,358 — (921 ) Interest credited — — — (159,276 ) — For the year ended December 31, 2016: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,226,970 $ 416,076 $ 330,649 $ 303,836 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (2,399 ) 12,197 (595 ) 801 Investment related gains (losses), net (4,756 ) — (2,153 ) 1,101 Included in other comprehensive income 10,022 47,692 (1,621 ) (2,696 ) Purchases (1) 312,720 — 103,553 138,522 Sales (1) (60,399 ) — (167,684 ) (38,681 ) Settlements (1) (195,016 ) — (38,495 ) (61,770 ) Transfers into Level 3 14,098 — 1,728 56,105 Transfers out of Level 3 (28,987 ) — (65,091 ) (177,938 ) Fair value, end of period $ 1,272,253 $ 475,965 $ 160,291 $ 219,280 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (2,343 ) $ 12,197 $ (158 ) $ 734 Investment related gains (losses), net (817 ) — (231 ) — For the year ended December 31, 2016 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 68,563 $ 26,265 $ 38,342 $ 14,065 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses 1,677 (487 ) 215 — Investment related gains (losses), net (876 ) — — — Included in other comprehensive income (5,887 ) 39 962 110 Purchases (1) 1,545 508 6,952 — Sales (1) (41,143 ) — — — Settlements (1) (552 ) (1,837 ) (599 ) (1,306 ) Transfers into Level 3 — — — — Transfers out of Level 3 (2,182 ) — (4,206 ) — Fair value, end of period $ 21,145 $ 24,488 $ 41,666 $ 12,869 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ 1,552 $ (487 ) $ 215 $ — For the year ended December 31, 2016 (continued): Short-term investments Funds withheld at interest-embedded derivatives Other assets - longevity swaps Interest- Other liabilities - mortality swaps Fair value, beginning of period $ — $ (76,698 ) $ 14,996 $ (1,070,584 ) $ (2,619 ) Total gains/losses (realized/unrealized) Included in earnings, net: Investment related gains (losses), net — 54,169 — 7,834 — Interest credited — — — 10,709 — Included in other comprehensive income — — (1,133 ) — — Other revenues — — 13,095 — (172 ) Purchases (1) 3,365 — — (12,725 ) — Settlements (1) (19 ) — — 74,458 329 Fair value, end of period $ 3,346 $ (22,529 ) $ 26,958 $ (990,308 ) $ (2,462 ) Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment related gains (losses), net $ — $ 54,169 $ — $ (4,579 ) $ — Other revenues — — 13,095 — (172 ) Interest credited — — — (63,748 ) — (1) The amount reported within purchases, sales and settlements is the purchase price (for purchases) and the sales/settlement proceeds (for sales and settlements) based upon the actual date purchased or sold/settled. Items purchased and sold/settled in the same period are excluded from the rollforward. The Company had no issuances during the period.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	For the year ended December 31, 2018: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,337,272 $ 593,942 $ 107,882 $ 123,474 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (1,045 ) 13,965 (129 ) 224 Investment related gains (losses), net (4,651 ) — 312 1,910 Included in other comprehensive income (32,983 ) (79,783 ) (1,786 ) (1,344 ) Purchases (1) 509,134 — 52,279 42,120 Sales (1) (106,005 ) — (4,961 ) (462 ) Settlements (1) (273,898 ) — (4,633 ) (57,476 ) Transfers into Level 3 9,948 — 3,031 73,289 Transfers out of Level 3 (106,847 ) — (145,140 ) (86,163 ) Fair value, end of period $ 1,330,925 $ 528,124 $ 6,855 $ 95,572 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (998 ) $ 13,965 $ 3 $ 209 Investment related gains (losses), net (6,320 ) — — — For the year ended December 31, 2018 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 3,234 $ 22,511 $ 41,203 $ 5,092 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses — (423 ) 9 — Investment related gains (losses), net 1 (208 ) — — Included in other comprehensive income (65 ) (436 ) 66 (86 ) Purchases (1) — 418 — — Sales (1) (1,751 ) — — — Settlements (1) (5 ) (3,837 ) (494 ) — Transfers into Level 3 1,752 — 9,859 — Transfers out of Level 3 (3,144 ) — (40,441 ) — Fair value, end of period $ 22 $ 18,025 $ 10,202 $ 5,006 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ — $ (417 ) $ 8 $ — For the year ended December 31, 2018 (continued): Equity securities Funds withheld at interest-embedded derivatives Short-term investments Other assets - longevity swaps Interest-sensitive contract Other liabilities - mortality swaps Fair value, beginning of period $ — $ 122,194 $ 3,096 $ 40,659 $ (1,014,228 ) $ (1,683 ) Total gains/losses (realized/unrealized) Included in earnings, net: Investment related gains (losses), net (12,600 ) (12,597 ) — — (15,455 ) — Interest credited — — — — 27,590 — Included in other comprehensive income — — 1 (2,085 ) — — Other revenues — — — 9,215 — (386 ) Purchases (1) 13,962 — 2,624 — (19,182 ) — Sales (1) (6,759 ) — (250 ) — — — Settlements (1) (48 ) — (461 ) — 76,410 1,700 Transfers into Level 3 38,905 — — — — — Transfers out of Level 3 — — (2,782 ) — — — Fair value, end of period $ 33,460 $ 109,597 $ 2,228 $ 47,789 $ (944,865 ) $ (369 ) Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment related gains (losses), net $ (15,992 ) $ (12,597 ) $ — $ — $ (22,393 ) $ — Other revenues — — — 9,215 — (386 ) Interest credited — — — — (48,819 ) — For the year ended December 31, 2017: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,272,253 $ 475,965 $ 160,291 $ 219,280 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (1,429 ) 13,180 (346 ) 1,776 Investment related gains (losses), net 4,991 — 729 245 Included in other comprehensive income (6,719 ) 104,797 2,341 7,044 Purchases (1) 408,995 — 76,792 45,215 Sales (1) (89,248 ) — (28,043 ) — Settlements (1) (285,958 ) — (18,988 ) (87,328 ) Transfers into Level 3 47,360 — 9,100 85,152 Transfers out of Level 3 (12,973 ) — (93,994 ) (147,910 ) Fair value, end of period $ 1,337,272 $ 593,942 $ 107,882 $ 123,474 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (1,457 ) $ 13,180 $ (196 ) $ 669 Investment related gains (losses), net (5,389 ) — (346 ) — For the year ended December 31, 2017 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 21,145 $ 24,488 $ 41,666 $ 12,869 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses 709 (461 ) (55 ) (1 ) Investment related gains (losses), net (595 ) — — — Included in other comprehensive income (71 ) 19 (15 ) (252 ) Purchases (1) — 465 — 496 Sales (1) (3,720 ) — — — Settlements (1) (5,404 ) (2,000 ) (843 ) (672 ) Transfers into Level 3 1,302 — 7,294 — Transfers out of Level 3 (10,132 ) — (6,844 ) (7,348 ) Fair value, end of period $ 3,234 $ 22,511 $ 41,203 $ 5,092 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ — $ (461 ) $ (54 ) $ (1 ) For the year ended December 31, 2017 (continued): Short-term investments Funds withheld at interest-embedded derivatives Other assets - longevity swaps Interest-sensitive contract Other liabilities - mortality swaps Fair value, beginning of period $ 3,346 $ (22,529 ) $ 26,958 $ (990,308 ) $ (2,462 ) Total gains/losses (realized/unrealized) Included in earnings, net: Investment related gains (losses), net — 144,723 — 32,166 — Interest credited — — — (80,062 ) — Included in other comprehensive income 11 — 4,343 — — Other revenues — — 9,358 — (921 ) Purchases (1) 3,703 — — (55,237 ) — Settlements (1) (335 ) — — 79,213 1,700 Transfers out of Level 3 (3,629 ) — — — — Fair value, end of period $ 3,096 $ 122,194 $ 40,659 $ (1,014,228 ) $ (1,683 ) Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment related gains (losses), net $ — $ 144,723 $ — $ 23,472 $ — Other revenues — — 9,358 — (921 ) Interest credited — — — (159,276 ) — For the year ended December 31, 2016: Fixed maturity securities - available-for-sale Corporate Canadian government RMBS ABS Fair value, beginning of period $ 1,226,970 $ 416,076 $ 330,649 $ 303,836 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses (2,399 ) 12,197 (595 ) 801 Investment related gains (losses), net (4,756 ) — (2,153 ) 1,101 Included in other comprehensive income 10,022 47,692 (1,621 ) (2,696 ) Purchases (1) 312,720 — 103,553 138,522 Sales (1) (60,399 ) — (167,684 ) (38,681 ) Settlements (1) (195,016 ) — (38,495 ) (61,770 ) Transfers into Level 3 14,098 — 1,728 56,105 Transfers out of Level 3 (28,987 ) — (65,091 ) (177,938 ) Fair value, end of period $ 1,272,253 $ 475,965 $ 160,291 $ 219,280 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ (2,343 ) $ 12,197 $ (158 ) $ 734 Investment related gains (losses), net (817 ) — (231 ) — For the year ended December 31, 2016 (continued): Fixed maturity securities - available-for-sale CMBS U.S. government State Other foreign government Fair value, beginning of period $ 68,563 $ 26,265 $ 38,342 $ 14,065 Total gains/losses (realized/unrealized) Included in earnings, net: Investment income, net of related expenses 1,677 (487 ) 215 — Investment related gains (losses), net (876 ) — — — Included in other comprehensive income (5,887 ) 39 962 110 Purchases (1) 1,545 508 6,952 — Sales (1) (41,143 ) — — — Settlements (1) (552 ) (1,837 ) (599 ) (1,306 ) Transfers into Level 3 — — — — Transfers out of Level 3 (2,182 ) — (4,206 ) — Fair value, end of period $ 21,145 $ 24,488 $ 41,666 $ 12,869 Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment income, net of related expenses $ 1,552 $ (487 ) $ 215 $ — For the year ended December 31, 2016 (continued): Short-term investments Funds withheld at interest-embedded derivatives Other assets - longevity swaps Interest- Other liabilities - mortality swaps Fair value, beginning of period $ — $ (76,698 ) $ 14,996 $ (1,070,584 ) $ (2,619 ) Total gains/losses (realized/unrealized) Included in earnings, net: Investment related gains (losses), net — 54,169 — 7,834 — Interest credited — — — 10,709 — Included in other comprehensive income — — (1,133 ) — — Other revenues — — 13,095 — (172 ) Purchases (1) 3,365 — — (12,725 ) — Settlements (1) (19 ) — — 74,458 329 Fair value, end of period $ 3,346 $ (22,529 ) $ 26,958 $ (990,308 ) $ (2,462 ) Unrealized gains and losses recorded in earnings for the period relating to those Level 3 assets and liabilities that were still held at the end of the period Included in earnings, net: Investment related gains (losses), net $ — $ 54,169 $ — $ (4,579 ) $ — Other revenues — — 13,095 — (172 ) Interest credited — — — (63,748 ) — (1) The amount reported within purchases, sales and settlements is the purchase price (for purchases) and the sales/settlement proceeds (for sales and settlements) based upon the actual date purchased or sold/settled. Items purchased and sold/settled in the same period are excluded from the rollforward. The Company had no issuances during the period.
Fair Value Assets Measured On Nonrecurring Basis [Text Block]	Nonrecurring Fair Value Measurements The following table presents information for financial instruments measured at an estimated fair value on a nonrecurring basis during the periods presented and still held at the reporting date (for example, when there is evidence of impairment). The estimated fair values for these financial instruments were determined using significant unobservable inputs (Level 3). Carrying Value After Measurement Net Investment Gains (Losses) At December 31, Years ended December 31, (dollars in thousands) 2018 2017 2018 2017 Limited partnership interests (1) $ 4,596 $ 4,656 $ (3,200 ) $ (7,204 ) Private equities (2) — 106 — (531 ) (1) The impaired limited partnership interests presented above were accounted for using the cost method. Impairments on these cost method investments were recognized at estimated fair value determined using the net asset values of the Company’s ownership interest as provided in the financial statements of the investees. The market for these investments has limited activity and price transparency. (2) The fair value of the Company’s private equity investments is based on external valuation models.
Financial Instruments Carrying Amounts And Estimated Fair Value [Table Text Block]	The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments, which were not measured at fair value on a recurring basis, as of December 31, 2018 and 2017 (dollars in thousands). This table excludes any payables or receivables for collateral under repurchase agreements and other transactions. The estimated fair value of the excluded amount approximates carrying value as they equal the amount of cash collateral received/paid. Estimated Fair Fair Value Measurement Using: December 31, 2018: Carrying Value (1) Value Level 1 Level 2 Level 3 NAV Assets: Mortgage loans on real estate $ 4,966,298 $ 4,917,416 $ — $ — $ 4,917,416 $ — Policy loans 1,344,980 1,344,980 — 1,344,980 — — Funds withheld at interest 5,655,055 5,802,518 — — 5,802,518 — Cash and cash equivalents 1,404,566 1,404,566 1,404,566 — — — Short-term investments 36,607 36,607 36,607 — — — Other invested assets 945,731 941,449 4,640 83,203 477,214 376,392 Accrued investment income 427,893 427,893 — 427,893 — — Liabilities: Interest-sensitive contract liabilities $ 14,547,436 $ 14,611,011 $ — $ — $ 14,611,011 $ — Long-term debt 2,787,873 2,752,047 — — 2,752,047 — Collateral finance and securitization notes 681,961 626,731 — — 626,731 — December 31, 2017: Assets: Mortgage loans on real estate $ 4,400,533 $ 4,477,654 $ — $ — $ 4,477,654 $ — Policy loans 1,357,624 1,357,624 — 1,357,624 — — Funds withheld at interest 5,955,092 6,275,623 — — 6,275,623 — Cash and cash equivalents 946,736 946,736 946,736 — — — Short-term investments 42,558 42,558 42,558 — — — Other invested assets 690,198 718,282 28,540 67,778 286,839 335,125 Accrued investment income 392,721 392,721 — 392,721 — — Liabilities: Interest-sensitive contract liabilities $ 12,683,872 $ 12,917,243 $ — $ — $ 12,917,243 $ — Long-term debt 2,788,365 2,959,912 — — 2,959,912 — Collateral finance and securitization notes 783,938 722,145 — — 722,145 — (1) Carrying values presented herein may differ from those in the Company’s consolidated balance sheets because certain items within the respective financial statement captions may be measured at fair value on a recurring basis.

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2018
Reinsurance Disclosures [Abstract]
Ceded Credit Risk [Table Text Block]	The following table presents information for the Company’s ceded reinsurance receivable assets, including the respective amount and A.M. Best rating for each reinsurer representing in excess of five percent of the total as of December 31, 2018 or 2017 (dollars in thousands): 2018 2017 Reinsurer A.M. Best Rating Amount % of Total Amount % of Total Reinsurer A A+ $ 303,036 40.0 % $ 301,478 38.6 % Reinsurer B A+ 193,324 25.5 203,898 26.1 Reinsurer C A 69,885 9.2 67,723 8.7 Reinsurer D A+ 40,004 5.3 40,528 5.2 Reinsurer E A++ 36,600 4.8 40,592 5.2 Other reinsurers 114,723 15.2 127,808 16.2 Total $ 757,572 100.0 % $ 782,027 100.0 %
Reinsurance Premium And Effect On Claims And Other Policy Benefits [Table Text Block]	The effect of reinsurance on net premiums is as follows (dollars in thousands): Years ended December 31, 2018 2017 2016 Direct $ 62,526 $ 61,571 $ 57,562 Reinsurance assumed 11,341,284 10,642,462 10,049,587 Reinsurance ceded (860,034 ) (862,903 ) (858,278 ) Net premiums $ 10,543,776 $ 9,841,130 $ 9,248,871 The effect of reinsurance on claims and other policy benefits as follows (dollars in thousands): Years ended December 31, 2018 2017 2016 Direct $ 107,405 $ 104,447 $ 105,435 Reinsurance assumed 9,997,173 9,281,590 8,621,647 Reinsurance ceded (785,649 ) (867,120 ) (733,707 ) Net claims and other policy benefits $ 9,318,929 $ 8,518,917 $ 7,993,375
Reinsurance Information [Table Text Block]	The effect of reinsurance on life insurance in force is shown in the following schedule (dollars in millions): Direct Assumed Ceded Net Assumed/Net % December 31, 2018 $ 1,363 $ 3,329,181 $ 186,172 $ 3,144,372 105.9 % December 31, 2017 1,462 3,297,275 205,529 3,093,208 106.6 December 31, 2016 1,576 3,062,525 214,727 2,849,374 107.5

Deferred Policy Acquisition C_2

Deferred Policy Acquisition Costs (Tables)	12 Months Ended
	Dec. 31, 2018
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred Policy Acquisition Costs [Table Text Block]	The following reflects the amounts of policy acquisition costs deferred and amortized (dollars in thousands): Years ended December 31, 2018 2017 2016 Balance, beginning of year $ 3,239,824 $ 3,338,605 $ 3,392,437 Capitalization 607,743 348,470 350,233 Amortization (including interest) (437,696 ) (432,474 ) (341,115 ) Change in value of embedded derivatives 14,658 (70,392 ) (40,077 ) Attributed to unrealized investment gains (losses) 26,608 (8,220 ) (3,541 ) Foreign currency translation (53,367 ) 63,835 (19,332 ) Balance, end of year $ 3,397,770 $ 3,239,824 $ 3,338,605

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	Pre-tax income for the years ended December 31, 2018, 2017 and 2016 consists of the following (dollars in thousands): 2018 2017 2016 Pre-tax income - U.S. $ 626,197 $ 870,532 $ 758,496 Pre-tax income - foreign 219,623 272,283 285,450 Total pre-tax income $ 845,820 $ 1,142,815 $ 1,043,946
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The provision for income tax expense for the years ended December 31, 2018, 2017 and 2016 consists of the following (dollars in thousands): 2018 2017 2016 Current income tax expense (benefit): U.S. $ 78,431 $ 131,108 $ 1,020 U.S. Tax Reform (68,080 ) — — Foreign 43,120 36,830 47,706 Total current 53,471 167,938 48,726 Deferred income tax expense (benefit): U.S. 62,890 159,853 273,928 U.S. Tax Reform 5,907 (1,033,755 ) — Foreign 7,710 26,598 19,849 Total deferred 76,507 (847,304 ) 293,777 Total provision for income taxes $ 129,978 $ (679,366 ) $ 342,503
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The Company’s effective tax rate differed from the U.S. federal income tax statutory rate of 21%, 35%, and 35% as a result of the following for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): 2018 2017 2016 Tax provision at U.S. statutory rate $ 177,622 $ 399,985 $ 365,381 Increase (decrease) in income taxes resulting from: U.S. Tax Reform (62,173 ) (1,033,755 ) — Foreign tax rate differing from U.S. tax rate 4,526 (21,867 ) (13,974 ) Differences in tax basis in foreign jurisdictions (23,257 ) (23,324 ) (17,770 ) Deferred tax valuation allowance 23,144 29,458 10,963 Amounts related to audit contingencies 1,516 (7,184 ) 111 Equity compensation excess benefit (6,103 ) (10,532 ) — Corporate rate changes 1,008 (6,065 ) — GILTI, net of credits 10,400 — — Subpart F for non-full inclusion companies 583 1,528 1,783 Foreign tax credits (2,544 ) (1,681 ) (1,683 ) Return to provision adjustments (1,305 ) (4,674 ) (1,473 ) Other, net 6,561 (1,255 ) (835 ) Total provision for income taxes $ 129,978 $ (679,366 ) $ 342,503 Effective tax rate 15.4 % (59.4 )% 32.8 %
Schedule Of Income Tax Expense Benefit Intraperiod Tax Allocation [Table Text Block]	Total income taxes for the years ended December 31, 2018, 2017 and 2016 were as follows (dollars in thousands): 2018 2017 2016 Provision for income taxes $ 129,978 $ (679,366 ) $ 342,503 Income tax from OCI and additional paid-in-capital: Net unrealized holding gain (loss) on debt and equity securities recognized for financial reporting purposes (367,933 ) 306,849 157,929 Exercise of stock options — — (162 ) Foreign currency translation 19,101 (42,153 ) 21,081 Unrealized pension and post retirement 134 404 1,772 Total income taxes provided $ (218,720 ) $ (414,266 ) $ 523,123
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities at December 31, 2018 and 2017 , are presented in the following tables (dollars in thousands): 2018 2017 Deferred income tax assets: Nondeductible accruals $ 86,092 $ 80,905 Differences between tax and financial reporting amounts concerning certain reinsurance transactions 102,014 96,043 Differences in the tax basis of cash and invested assets 28,398 557 Investment income differences 80,200 43,230 Deferred acquisition costs capitalized for tax 124,707 88,531 Net operating loss carryforward 405,958 535,374 Capital loss and tax credit carryforwards 32,897 102,143 Subtotal 860,266 946,783 Valuation allowance (181,110 ) (226,884 ) Total deferred income tax assets 679,156 719,899 Deferred income tax liabilities: Deferred acquisition costs capitalized for financial reporting 843,328 627,378 Differences between tax and financial reporting amounts concerning certain reinsurance transactions 1,151,419 1,547,101 Differences in the tax basis of cash and invested assets 345,836 674,569 Investment income differences 9,493 1,858 Differences in foreign currency translation 52,928 33,803 Anticipated future tax credit reduction 25,433 — Total deferred income tax liabilities 2,428,437 2,884,709 Net deferred income tax liabilities $ 1,749,281 $ 2,164,810 Balance sheet presentation of net deferred income tax liabilities: Included in other assets $ 49,519 $ 33,499 Included in deferred income taxes 1,798,800 2,198,309 Net deferred income tax liabilities $ 1,749,281 $ 2,164,810
Summary of Operating Loss Carryforwards [Table Text Block]	The following table presents consolidated net operating losses (“NOL”) as of December 31, 2018 (dollars in millions): 2018 NOL with no expiration and with no valuation allowance $ 52 NOL with a full valuation allowance 167 NOL with no expiration and a partial valuation allowance 396 NOL with expiration dates between 2029 & 2035 with no valuation allowance 1,118 Total net operating loss carryforwards $ 1,733
Summary of Income Tax Contingencies [Table Text Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31, 2018, 2017 and 2016 , is as follows (dollars in thousands): Total Unrecognized Tax Benefits 2018 2017 2016 Beginning balance, January 1 $ 321,224 $ 297,290 $ 296,213 Accounting for business combinations 521 — — Additions for tax positions of prior years 255,970 247,596 226,720 Reductions for tax positions of prior years (256,587 ) (246,894 ) (229,719 ) Additions for tax positions of current year 3,682 36,438 4,186 Payment on deposit (185 ) — — Settlements with tax authorities — (13,206 ) (110 ) Ending balance, December 31 $ 324,625 $ 321,224 $ 297,290

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Schedule of Changes in Projected Benefit Obligations [Table Text Block]	A December 31 measurement date is used for all of the defined benefit and postretirement plans. The status of these plans as of December 31, 2018 and 2017 is summarized below (dollars in thousands): December 31, Pension Benefits Other Benefits 2018 2017 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 172,143 $ 161,955 $ 70,198 $ 60,524 Service cost 12,502 10,686 3,028 2,543 Interest Cost 5,405 5,326 2,319 2,118 Participant contributions — — 432 354 Amendments — 159 — — Actuarial (gains) losses (1,045 ) 11,336 (7,172 ) 5,510 Settlement (gains) losses — (438 ) — — Settlements — (12,907 ) — — Benefits paid (7,801 ) (5,974 ) (1,409 ) (851 ) Foreign exchange translations and other adjustments (2,600 ) 2,000 — — Benefit obligation at end of year $ 178,604 $ 172,143 $ 67,396 $ 70,198
Schedule of Changes in Fair Value of Plan Assets [Table Text Block]	December 31, Pension Benefits Other Benefits 2018 2017 2018 2017 Change in plan assets: Fair value of plan assets at beginning of year $ 103,236 $ 84,770 $ — $ — Actual return on plan assets (6,464 ) 14,481 — — Employer contributions 13,590 22,866 977 497 Participant contributions — — 432 354 Disbursement for settlements — (12,907 ) — — Benefits paid and expenses (7,801 ) (5,974 ) (1,409 ) (851 ) Fair value of plan assets at end of year $ 102,561 $ 103,236 $ — $ — Funded status at end of year $ (76,043 ) $ (68,907 ) $ (67,396 ) $ (70,198 )
Schedule of Net Funded Status [Table Text Block]	December 31, Qualified Plans Non-Qualified Plans (1) Total 2018 2017 2018 2017 2018 2017 Aggregate fair value of plan assets $ 102,561 $ 103,236 $ — $ — $ 102,561 $ 103,236 Aggregate projected benefit obligations 112,093 107,072 66,511 65,071 178,604 172,143 Under funded $ (9,532 ) $ (3,836 ) $ (66,511 ) $ (65,071 ) $ (76,043 ) $ (68,907 ) (1) For non-qualified plans, there are no required funding levels.
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	December 31, Pension Benefits Other Benefits 2018 2017 2018 2017 Amounts recognized in accumulated other comprehensive income: Net actuarial loss $ 48,744 $ 40,058 $ 25,923 $ 35,672 Net prior service cost (credit) 436 804 (10,491 ) (11,806 ) Total $ 49,180 $ 40,862 $ 15,432 $ 23,866
Schedule Of Projected Benefit Obligations In Excess Of Fair Value Of Plan Assets [Table Text Block]	The following table presents information for qualified and non-qualified pension plans with a projected benefit obligation in excess of plan assets as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Projected benefit obligation $ 178,604 $ 172,143 Fair value of plan assets 102,561 103,236
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block]	The following table presents information for pension plans with an accumulated benefit obligation in excess of plan assets as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Accumulated benefit obligation $ 174,400 $ 169,705 Fair value of plan assets 102,561 103,236
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	The components of net periodic benefit cost, included in other operating expenses on the consolidated statements of income, and other changes in plan assets and benefit obligations recognized in other comprehensive income were as follows (dollars in thousands): Pension Benefits Other Benefits 2018 2017 2016 2018 2017 2016 Net periodic benefit cost: Service cost $ 12,502 $ 10,686 $ 10,319 $ 3,028 $ 2,543 $ 2,883 Interest cost 5,405 5,326 4,790 2,319 2,118 2,259 Expected return on plan assets (7,535 ) (6,215 ) (5,138 ) — — — Amortization of net actuarial losses 3,728 4,382 4,323 2,577 1,992 1,827 Amortization of prior service cost (credit) 344 344 294 (1,315 ) (1,315 ) (622 ) Settlements — 4,785 1,026 — — — Net periodic benefit cost 14,444 19,308 15,614 6,609 5,338 6,347 Other changes in plan assets and benefit obligations recognized in other comprehensive income: Net actuarial (gains) losses 12,954 2,633 8,785 (7,172 ) 5,507 6,228 Amortization of net actuarial (losses) (3,728 ) (4,382 ) (4,323 ) (2,577 ) (1,992 ) (1,827 ) Amortization of prior service (cost) credit (344 ) (344 ) (294 ) 1,315 1,315 622 Settlements — (4,785 ) (1,026 ) — — — Prior service cost (credit) — 159 — — — (13,743 ) Foreign exchange translations and other adjustments (565 ) 759 707 — — — Total recognized in other comprehensive income 8,317 (5,960 ) 3,849 (8,434 ) 4,830 (8,720 ) Total recognized in net periodic benefit cost and other comprehensive income $ 22,761 $ 13,348 $ 19,463 $ (1,825 ) $ 10,168 $ (2,373 )
Schedule of Expected Benefit Payments [Table Text Block]	The following benefit payments, which reflect expected future service as appropriate, are expected to be paid (dollars in thousands): Pension Benefits Other Benefits 2019 $ 9,977 $ 1,528 2020 12,013 1,835 2021 11,663 2,209 2022 14,229 2,633 2023 14,128 3,009 2024-2028 77,832 20,359
Schedule of Assumptions Used [Table Text Block]	Weighted average assumptions used to determine the accumulated benefit obligation and net benefit cost or income were as follows: Pension Benefits Other Benefits 2018 2017 2016 2018 2017 2016 Discount rate used to determine benefit obligation 4.02 % 3.40 % 3.80 % 4.17 % 3.56 % 4.10 % Discount rate used to determine net benefit cost or income 3.41 % 3.81 % 3.95 % 3.56 % 4.10 % 4.43 % Expected long-term rate of return on plan assets 7.35 % 7.35 % 7.35 % — % — % — % Rate of compensation increases 4.17 % 4.16 % 4.08 % — % — % — %
Schedule of Health Care Cost Trend Rates [Table Text Block]	The assumed health care cost trend rates used in measuring the accumulated non-pension post-retirement benefit obligation were as follows: December 31, 2018 2017 Pre-Medicare eligible claims 8% down to 5% in 2024 9% down to 5% in 2024 Medicare eligible claims 8% down to 5% in 2024 9% down to 5% in 2024
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]	The assumed health care cost trend rates used in measuring the accumulated non-pension post-retirement benefit obligation were as follows: December 31, 2018 2017 Pre-Medicare eligible claims 8% down to 5% in 2024 9% down to 5% in 2024 Medicare eligible claims 8% down to 5% in 2024 9% down to 5% in 2024
Schedule of Allocation of Plan Assets [Table Text Block]	The fair values of the Company’s qualified pension plan assets as of December 31, 2018 and 2017 are summarized below (dollars in thousands): December 31, 2018 Fair Value Measurement Using: Total Level 1 Level 2 Level 3 Mutual Funds (1) $ 102,414 $ 102,414 $ — $ — Cash 147 147 — — Total $ 102,561 $ 102,561 $ — $ — (1) Mutual funds were invested 25% in U.S. equity funds, 42% in U.S. fixed income funds, 17% in non-U.S. equity funds and 16% in other. December 31, 2017 Fair Value Measurement Using: Total Level 1 Level 2 Level 3 Mutual Funds (2) $ 103,106 $ 103,106 $ — $ — Cash 130 130 — — Total $ 103,236 $ 103,236 $ — $ — (2) Mutual funds were invested 27% in U.S. equity funds, 36% in U.S. fixed income funds, 22% in non-U.S. equity funds and 15% in other.

Financial Condition and Net I_2

Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2018
Statutory Basis [Abstract]
Statutory Accounting Practices Disclosure [Table Text Block]	Statutory net income, and capital and surplus of the Company’s insurance subsidiaries, determined in accordance with statutory accounting practices prescribed by the applicable state insurance department or local regulatory authority are as follows (dollars in thousands): Statutory Capital & Surplus Statutory Net Income (Loss) 2018 2017 2018 2017 2016 RGA Americas Reinsurance Company, Ltd. $ 4,298,368 $ 4,833,890 $ 208,999 $ 624,145 $ 282,226 RGA Reinsurance (U.S.) 2,078,654 1,584,007 659,941 138,359 148,576 Reinsurance Company of Missouri 2,053,379 1,557,453 (24,907 ) (183,136 ) 272,038 RGA Reinsurance Company (Barbados) Ltd. 1,169,790 1,278,006 48,779 309,346 95,859 RGA Atlantic Reinsurance Company Ltd. 1,083,181 812,307 256,080 213,511 110,172 RGA Life Reinsurance Company of Canada 896,760 1,006,190 (37,922 ) 25,971 13,947 RGA Australia 433,406 476,528 (37,208 ) 78,497 (7,694 ) Other insurance subsidiaries 2,572,307 2,694,317 345,249 65,658 130,289
Reconciliation Of NAIC SAP And Prescribed Practice [Text Block]	A reconciliation of the Company’s surplus between NAIC SAP and practices prescribed by the state of domicile is shown below (dollars in thousands): December 31, 2018 2017 Prescribed practice – surplus note $ 624,266 $ 726,531 Prescribed practice – letters of credit (976,100 ) (960,100 ) Surplus (deficit) – NAIC SAP $ (351,834 ) $ (233,569 )

Commitments Contingencies and_2

Commitments Contingencies and Guarantees (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block]	The Company’s commitments to fund investments as of December 31, 2018 and 2017 are presented in the following table (dollars in thousands): 2018 2017 Limited partnership interests and joint ventures $ 523,903 $ 485,197 Commercial mortgage loans 22,605 40,815 Bank loans and private placements 137,076 60,472 Equity release mortgages 264,858 153,937
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future minimum office space annual rentals under non-cancelable operating leases at December 31, 2018 are as follows (dollars in thousands): Operating Leases 2019 $ 13,578 2020 11,541 2021 9,447 2022 8,587 2023 8,248 Thereafter 14,101
Other Commitments [Table Text Block]	The following table presents the maximum potential obligation for these commitments as of December 31, 2018 (dollars in millions): Commitment Period Maximum Potential Obligation 2023 $ 500.0 2033 450.0 2034 2,000.0 2035 1,314.2 2036 2,658.0 2037 6,750.0 2038 800.0
Schedule of Guarantor Obligations [Table Text Block]	RGA’s guarantees issued as of December 31, 2018 and 2017 are reflected in the following table (dollars in thousands): 2018 2017 Treaty guarantees $ 1,392,352 $ 1,047,449 Treaty guarantees, net of assets in trust 1,291,445 926,393 Securities borrowing and repurchase arrangements 269,980 294,325 Financing arrangements 61,273 86,183 Lease obligations 392 1,662

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	The Company’s long-term debt consists of the following as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 $400 million 6.45% Senior Notes due 2019 $ 399,941 $ 399,873 $400 million 5.00% Senior Notes due 2021 399,466 399,245 $400 million 4.70% Senior Notes due 2023 399,288 399,138 $400 million 3.95% Senior Notes due 2026 399,988 399,987 $100 million 4.09% Promissory Note due 2039 89,098 91,787 $400 million 6.20% Subordinated Debentures due 2042 400,000 400,000 $400 million 5.75% Subordinated Debentures due 2056 400,000 400,000 $400 million Variable Rate Junior Subordinated Debentures due 2065 318,743 318,740 Sub-total 2,806,524 2,808,770 Unamortized issuance costs (18,651 ) (20,405 ) Long-term Debt $ 2,787,873 $ 2,788,365
Schedule of Maturities of Long-term Debt [Table Text Block]	Future principal payments due on long-term debt, excluding discounts, as of December 31, 2018 , were as follows (dollars in thousands): Calendar Year 2019 2020 2021 2022 2023 Thereafter Long-term debt $ 402,802 $ 2,919 $ 403,040 $ 3,167 $ 403,299 $ 1,593,674
Schedule of Line of Credit Facilities [Table Text Block]	The following table provides additional information on the Company’s existing committed credit facilities as of December 31, 2018 and 2017 (dollars in thousands): Amount Utilized (1) December 31, Current Capacity Maturity Date 2018 2017 Basis of Fees $191,583 (2) March 2019 $ 4,156 $ 5,952 Fixed 188,000 November 2019 188,000 188,000 Fixed 105,735 (2) December 2019 105,735 117,135 Fixed 100,000 June 2020 — 75,573 Fixed 100,000 May 2021 61,000 100,000 Fixed 75,000 June 2021 33,900 61,900 Fixed 500,000 May 2022 395,000 500,000 Debt rating and utilization % 850,000 August 2023 18,153 95,564 Senior unsecured long-term debt rating (1) Represents issued but undrawn letters of credit. There was no cash borrowed for the periods presented. (2) Foreign currency denominated facility, amounts presented are in U.S. dollars.

Collateral Finance and Securi_2

Collateral Finance and Securitization Notes Collateral Finance and Securitization Notes (Tables)	12 Months Ended
	Dec. 31, 2018
Collateralized Financings [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	The Company’s collateral finance and securitization notes consist of the following as of December 31, 2018 and 2017 (dollars in thousands): 2018 2017 Timberlake Financial $ 368,207 $ 411,951 RGA Barbados 131,602 159,100 Chesterfield Financial 185,700 217,800 Unamortized issuance costs (3,548 ) (4,913 ) Total $ 681,961 $ 783,938

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated [Table Text Block]	For the years ended December 31, 2018 2017 2016 Revenues: U.S. and Latin America: Traditional $ 6,295,733 $ 6,100,171 $ 5,964,968 Financial Solutions 907,245 1,150,378 840,446 Total 7,202,978 7,250,549 6,805,414 Canada: Traditional 1,224,404 1,103,520 1,118,004 Financial Solutions 48,588 48,938 46,938 Total 1,272,992 1,152,458 1,164,942 Europe, Middle East and Africa: Traditional 1,494,605 1,362,075 1,195,149 Financial Solutions 349,886 311,071 340,518 Total 1,844,491 1,673,146 1,535,667 Asia Pacific: Traditional 2,416,848 2,210,686 1,771,150 Financial Solutions 54,479 73,775 63,382 Total 2,471,327 2,284,461 1,834,532 Corporate and Other 83,876 155,155 180,956 Total $ 12,875,664 $ 12,515,769 $ 11,521,511
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]	For the years ended December 31, 2018 2017 2016 Income (loss) before income taxes: U.S. and Latin America: Traditional $ 286,410 $ 373,434 $ 371,101 Financial Solutions 250,478 401,584 283,380 Total 536,888 775,018 654,481 Canada: Traditional 112,308 120,218 134,705 Financial Solutions 9,576 16,643 7,945 Total 121,884 136,861 142,650 Europe, Middle East and Africa: Traditional 55,119 70,486 30,059 Financial Solutions 196,387 123,514 138,007 Total 251,506 194,000 168,066 Asia Pacific: Traditional 177,501 148,786 113,928 Financial Solutions (5,966 ) 13,130 4,063 Total 171,535 161,916 117,991 Corporate and Other (235,993 ) (124,980 ) (39,242 ) Total $ 845,820 $ 1,142,815 $ 1,043,946
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table Text Block]	For the years ended December 31, 2018 2017 2016 Interest expense: Corporate and Other $ 147,355 $ 146,025 $ 137,623 Total $ 147,355 $ 146,025 $ 137,623 For the years ended December 31, 2018 2017 2016 Depreciation and amortization: U.S. and Latin America: Traditional $ 272,555 $ 284,959 $ 271,732 Financial Solutions 95,306 208,790 155,560 Total 367,861 493,749 427,292 Canada: Traditional 22,109 24,057 22,170 Financial Solutions 9 10 11 Total 22,118 24,067 22,181 Europe, Middle East and Africa: Traditional 45,140 35,000 46,562 Financial Solutions 384 91 72 Total 45,524 35,091 46,634 Asia Pacific: Traditional 114,870 114,333 45,562 Financial Solutions 1,885 1,448 1,492 Total 116,755 115,781 47,054 Corporate and Other 22,104 37,276 13,894 Total $ 574,362 $ 705,964 $ 557,055
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	The table above includes amortization of DAC, including the effect from investment related gains and losses. For the years ended December 31, 2018 2017 Assets: U.S. and Latin America: Traditional $ 19,235,781 $ 18,603,423 Financial Solutions 19,870,388 15,959,206 Total 39,106,169 34,562,629 Canada: Traditional 4,200,792 4,161,452 Financial Solutions 154,000 126,372 Total 4,354,792 4,287,824 Europe, Middle East and Africa: Traditional 3,643,174 3,099,495 Financial Solutions 4,737,529 5,274,993 Total 8,380,703 8,374,488 Asia Pacific: Traditional 5,680,978 4,915,442 Financial Solutions 1,180,745 1,198,585 Total 6,861,723 6,114,027 Corporate and Other 5,831,858 7,175,850 Total $ 64,535,245 $ 60,514,818

Policy Claims and Benefits (Tab

Policy Claims and Benefits (Tables)	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Short-duration Insurance Contracts, Claims Development [Table Text Block]	U.S. and Latin America As of (in thousands) December 31, 2018 Incurred Claims and Allocated Claim Adjustments, Net of Reinsurance (1) Total of Incurred-but-Not-Reported Liabilities Plus Expected Development on Reported Claims Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 322,579 $ 309,119 $ 297,037 $ 298,262 $ 299,098 $ 297,688 $ 296,717 $ — 2013 349,262 332,907 338,977 336,552 336,436 336,323 24 2014 407,953 411,373 396,383 397,151 396,010 272 2015 459,524 460,917 465,167 461,947 1,505 2016 500,843 499,785 500,725 4,885 2017 485,442 513,722 27,190 2018 538,456 234,548 Total $ 3,043,900 Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net of Reinsurance (1) Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 109,323 $ 222,139 $ 243,890 $ 252,018 $ 258,297 $ 263,565 $ 268,073 2013 114,457 248,828 277,130 285,817 292,067 297,126 2014 128,813 304,578 337,081 349,078 356,026 2015 146,196 360,658 407,282 422,102 2016 184,940 392,517 436,892 2017 189,853 402,759 2018 182,560 Total $ 2,365,538 All outstanding claims prior to 2012, net of reinsurance 178,024 Liabilities for claims and claim adjustment expense, net of reinsurance $ 856,386 (1) 2012-2017 Unaudited. Asia Pacific As of (in thousands) December 31, 2018 Incurred Claims and Allocated Claim Adjustments, Net of Reinsurance (1) Total of Incurred-but-Not-Reported Liabilities Plus Expected Development on Reported Claims Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 207,882 $ 279,008 $ 283,316 $ 286,632 $ 294,265 $ 303,340 $ 309,287 $ 10,352 2013 292,769 313,126 303,779 301,168 314,283 328,017 16,728 2014 277,049 300,336 265,431 272,247 284,237 21,339 2015 278,491 257,146 251,650 267,292 32,392 2016 227,653 211,425 212,722 40,376 2017 216,499 214,707 63,383 2018 253,691 156,761 Total $ 1,869,953 Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net of Reinsurance (1) Accident Year For the Years Ended December 31, 2012 2013 2014 2015 2016 2017 2018 2012 $ 49,321 $ 135,322 $ 185,322 $ 222,987 $ 243,549 $ 259,917 $ 274,830 2013 49,805 144,247 209,347 235,923 261,299 282,961 2014 34,519 135,668 177,439 206,176 228,873 2015 48,962 118,579 167,350 202,273 2016 38,310 97,769 133,091 2017 35,442 87,037 2018 31,871 Total $ 1,240,936 All outstanding claims prior to 2012, net of reinsurance 112,373 Liabilities for claims and claim adjustment expense, net of reinsurance $ 741,390 (1) 2012-2017 Unaudited.
Short-duration Insurance Contracts, Schedule of Historical Claims Duration [Table Text Block]	The following is unaudited supplementary information about average historical claims duration as of December 31, 2018 : Average Annual Payout of Incurred Claims by Age, Net of Reinsurance Years 1 2 3 4 5 6 7 U.S. and Latin America 34.7 % 41.9 % 8.6 % 2.9 % 1.9 % 1.6 % 1.5 % Asia Pacific 15.5 % 28.4 % 17.1 % 10.9 % 7.5 % 5.9 % 4.8 %
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table Text Block]	The reconciliation of the net incurred and paid claims development tables to the liability for claims and claim adjustment expense in the consolidated balance sheet as of December 31, 2018 is as follows (dollars in thousands): 2018 Liabilities for claims and claim adjustment expense, net of reinsurance: U.S. and Latin America $ 856,386 Asia Pacific 741,390 Liabilities for claims and claim adjustment expense, net of reinsurance 1,597,776 Adjustments to reconcile to total policy claims and future policy benefits: Reinsurance recoverable 16,121 Effect of discounting (141,689 ) Unallocated claims adjustment expense 5,907 Total adjustments (119,661 ) Other short-duration contracts: Canada 128,831 Europe, Middle East and Africa 383,936 Other 177,416 Liability for unpaid claims and claim adjustment expense - short-duration 2,168,298 Liability for unpaid claims and claim adjustment expense - long-duration 4,416,370 Total liability for unpaid claims and claim adjustment expense (included in future policy benefits and other policy-related balances) $ 6,584,668
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]	The liability for unpaid claims is reported in future policy benefits and other policy-related balances within the Company’s consolidated balance sheet. Activity associated with unpaid claims is summarized below (dollars in thousands): 2018 2017 2016 Balance at beginning of year $ 5,896,469 $ 5,180,802 $ 4,977,836 Less: reinsurance recoverable (455,547 ) (394,821 ) (405,583 ) Net balance at beginning of year 5,440,922 4,785,981 4,572,253 Incurred: Current year 10,048,866 8,911,640 8,562,036 Prior years 131,181 14,364 (134,765 ) Total incurred 10,180,047 8,926,004 8,427,271 Payments: Current year (4,602,535 ) (4,513,606 ) (4,385,839 ) Prior years (4,691,722 ) (4,004,038 ) (3,777,137 ) Total payments (9,294,257 ) (8,517,644 ) (8,162,976 ) Other changes: Interest accretion 24,802 19,443 18,151 Foreign exchange adjustments (199,428 ) 227,138 (68,718 ) Total other changes (174,626 ) 246,581 (50,567 ) Net balance at end of year 6,152,086 5,440,922 4,785,981 Plus: reinsurance recoverable 432,582 455,547 394,821 Balance at end of year $ 6,584,668 $ 5,896,469 $ 5,180,802

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Schedule of Stock by Class [Table Text Block]	The changes in number of common stock shares, issued, held in treasury and outstanding are as follows for the periods indicated: Issued Held In Treasury Outstanding Balance, December 31, 2015 79,137,758 13,933,232 65,204,526 Common Stock acquired — 1,356,892 (1,356,892 ) Stock-based compensation (1) — (454,868 ) 454,868 Balance, December 31, 2016 79,137,758 14,835,256 64,302,502 Common Stock acquired — 208,680 (208,680 ) Stock-based compensation (1) — (358,273 ) 358,273 Balance, December 31, 2017 79,137,758 14,685,663 64,452,095 Common Stock acquired — 1,932,055 (1,932,055 ) Stock-based compensation (1) — (294,328 ) 294,328 Balance, December 31, 2018 79,137,758 16,323,390 62,814,368 (1) Represents net shares issued from treasury pursuant to the Company’s stock-based compensation programs.
Class of Treasury Stock [Table Text Block]	The following table summarizes the Company’s current share repurchase program activity for the years ended 2018 and 2017 (dollar amounts in thousands, except per share amounts): Year of Repurchase Shares Repurchased Amount Paid Average Per Share 2018 1,932,055 $ 283,524 $ 146.75 2017 208,680 26,897 $ 128.89 Total 2,140,735 $ 310,421
Schedule of Comprehensive Income (Loss) [Table Text Block]	Accumulated other comprehensive income (loss) The following table presents the components of the Company’s other comprehensive income (loss) for the years ended December 31, 2018, 2017 and 2016 (dollars in thousands): For the year ended December 31, 2018 : Before-Tax Amount Tax (Expense) Benefit After-Tax Amount Foreign currency translation adjustments: Change arising during year $ (148,018 ) $ (759 ) $ (148,777 ) Foreign currency swap 87,344 (18,342 ) 69,002 Net foreign currency translation adjustments (60,674 ) (19,101 ) (79,775 ) Unrealized gains on investments: (1) Unrealized net holding gains arising during the year (1,834,656 ) 393,653 (1,441,003 ) Less: Reclassification adjustment for net gains realized in net income (122,221 ) 25,720 (96,501 ) Net unrealized gains (1,712,435 ) 367,933 (1,344,502 ) Unrealized pension and postretirement benefits: Net prior service cost arising during the year (947 ) 182 (765 ) Net gain arising during the period 1,063 (316 ) 747 Unrealized pension and postretirement benefits, net 116 (134 ) (18 ) Other comprehensive income (loss) $ (1,772,993 ) $ 348,698 $ (1,424,295 ) For the year ended December 31, 2017 : Before-Tax Amount Tax (Expense) Benefit After-Tax Amount Foreign currency translation adjustments: Change arising during year $ 74,926 $ 25,369 $ 100,295 Foreign currency swap (47,953 ) 16,784 (31,169 ) Net foreign currency translation adjustments 26,973 42,153 69,126 Unrealized gains on investments: (1) Unrealized net holding gains arising during the year 1,029,591 (313,729 ) 715,862 Less: Reclassification adjustment for net gains realized in net income 25,039 (7,011 ) 18,028 Net unrealized gains 1,004,552 (306,718 ) 697,834 Change in unrealized OTTI on fixed maturity securities 375 (131 ) 244 Unrealized pension and postretirement benefits: Net prior service cost arising during the year 11,717 (4,095 ) 7,622 Net gain arising during the period (10,587 ) 3,691 (6,896 ) Unrealized pension and postretirement benefits, net 1,130 (404 ) 726 Other comprehensive income (loss) $ 1,033,030 $ (265,100 ) $ 767,930 For the year ended December 31, 2016 : Before-Tax Amount Tax (Expense) Benefit After-Tax Amount Foreign currency translation adjustments: Change arising during year $ 39,925 $ (24,663 ) $ 15,262 Foreign currency swap (10,234 ) 3,582 (6,652 ) Net foreign currency translation adjustments 29,691 (21,081 ) 8,610 Unrealized gains on investments: (1) Unrealized net holding gains arising during the year 641,606 (180,448 ) 461,158 Less: Reclassification adjustment for net gains realized in net income 65,798 (23,029 ) 42,769 Net unrealized gains 575,808 (157,419 ) 418,389 Change in unrealized OTTI on fixed maturity securities 1,457 (510 ) 947 Unrealized pension and postretirement benefits: Net prior service cost arising during the year 444 (149 ) 295 Net gain arising during the period 4,427 (1,623 ) 2,804 Unrealized pension and postretirement benefits, net 4,871 (1,772 ) 3,099 Other comprehensive income (loss) $ 611,827 $ (180,782 ) $ 431,045 (1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.
Components Of Accumulated Other Comprehensive Income [Table Text Block]	A summary of the components of net unrealized appreciation (depreciation) of balances carried at fair value is as follows (dollars in thousands): For the years ended December 31, 2018 2017 2016 Change in net unrealized appreciation (depreciation) on: Fixed maturity securities available-for-sale $ (1,759,230 ) $ 987,570 $ 561,906 Other investments (1) 20,187 25,577 18,900 Effect on unrealized appreciation on: Deferred policy acquisition costs 26,608 (8,220 ) (3,541 ) Net unrealized appreciation (depreciation) $ (1,712,435 ) $ 1,004,927 $ 577,265 (1) Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The balance of and changes in each component of AOCI were as follows (dollars in thousands): Accumulated Currency Translation Adjustments Unrealized Appreciation (Depreciation) of Investments (1) Pension and Postretirement Benefits Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2015 $ (181,151 ) $ 935,697 $ (46,262 ) $ 708,284 OCI before reclassifications 29,691 646,887 (951 ) 675,627 Amounts reclassified from AOCI — (69,622 ) 5,822 (63,800 ) Deferred income tax benefit (expense) (21,081 ) (157,929 ) (1,772 ) (180,782 ) Balance, December 31, 2016 (172,541 ) 1,355,033 (43,163 ) 1,139,329 OCI before reclassifications 26,973 1,039,387 (4,273 ) 1,062,087 Amounts reclassified from AOCI — (34,460 ) 5,403 (29,057 ) Deferred income tax benefit (expense) 42,153 (306,849 ) (404 ) (265,100 ) Adoption of new accounting standard 17,065 147,550 (8,243 ) 156,372 Balance, December 31, 2017 (86,350 ) 2,200,661 (50,680 ) 2,063,631 OCI before reclassifications (60,674 ) (1,860,789 ) (5,218 ) (1,926,681 ) Amounts reclassified from AOCI — 148,354 5,334 153,688 Deferred income tax benefit (expense) (19,101 ) 367,933 (134 ) 348,698 Adoption of new accounting standard (2,573 ) — — (2,573 ) Balance, December 31, 2018 $ (168,698 ) $ 856,159 $ (50,698 ) $ 636,763 (1) Includes cash flow hedges of $8,788 , $2,619 and $(2,496) as of December 31, 2018, 2017 and 2016 , respectively. See Note 5 for additional information on cash flow hedges.
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following table presents the amounts of AOCI reclassifications for the years ended December 31, 2018 and 2017 (dollars in thousands): Amount Reclassified from AOCI Details about AOCI Components 2018 2017 Affected Line Item in Statement of Income Net unrealized investment gains (losses): Net unrealized gains and losses on available-for-sale securities $ (122,221 ) $ 25,039 Investment related gains (losses), net Cash flow hedges - Interest rate 183 (79 ) (1) Cash flow hedges - Currency/Interest rate 292 380 (1) Cash flow hedges - Forward bond purchase commitments — 900 (1) Deferred policy acquisition costs attributed to unrealized gains and losses (26,608 ) 8,220 (2) Total (148,354 ) 34,460 Provision for income taxes 31,208 (10,308 ) Net unrealized gains (losses), net of tax $ (117,146 ) $ 24,152 Amortization of defined benefit plan items: Prior service cost (credit) $ 971 $ 971 (3) Actuarial gains/(losses) (6,305 ) (6,374 ) (3) Total (5,334 ) (5,403 ) Provision for income taxes 1,176 1,891 Amortization of defined benefit plans, net of tax $ (4,158 ) $ (3,512 ) Total reclassifications for the period $ (121,304 ) $ 20,640 (1) See Note 5 for information on cash flow hedges. (2) See Note 8 for information on deferred policy acquisition costs. (3) See Note 10 for information on employee benefit plans.

Equity Based Compensation (Tabl

Equity Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	The following table presents a summary of stock option activity: Number of Options Weighted-Average Exercise Price Aggregate Intrinsic Value (in millions) Outstanding December 31, 2017 2,309,769 $ 75.17 Granted 164,889 $ 150.87 Exercised (286,874 ) $ 59.45 Forfeited (17,341 ) $ 119.63 Outstanding December 31, 2018 2,170,443 $ 82.65 $ 126.7 Options exercisable 1,633,182 $ 73.09 $ 110.1
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Options Outstanding Options Exercisable Range of Exercise Prices Number Outstanding as of 12/31/2018 Weighted-Average Remaining Contractual Life (years) Weighted- Average Exercise Price Number Exercisable as of 12/31/2018 Weighted-Average Exercise Price $0.00 - $49.99 163,805 0.9 $ 43.97 163,805 $ 43.97 $50.00 - $59.99 775,518 3.5 $ 58.26 775,518 $ 58.26 $60.00 - $69.99 839 4.2 $ 60.24 839 $ 60.24 $70.00 - $79.99 159,593 5.2 $ 78.48 159,593 $ 78.48 $90.00 + 1,070,688 7.4 $ 106.87 533,427 $ 102.00 Totals 2,170,443 5.3 $ 82.65 1,633,182 $ 73.09
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following table presents the weighted average assumptions used to determine the fair value of stock options issued: For the years ended December 31, 2018 2017 2016 Dividend yield 1.33 % 1.26 % 1.58 % Risk-free rate of return 2.79 % 2.32 % 1.69 % Expected volatility 21.4 % 22.8 % 28.1 % Expected life (years) 7.0 7.0 7.0 Weighted average exercise price of stock options granted $ 150.87 $ 129.72 $ 93.53 Weighted average fair value of stock options granted $ 36.31 $ 31.57 $ 24.52
Share-based Compensation, Activity [Table Text Block]	The following table presents a summary of Performance Share and Restricted Stock Unit activity: Performance Contingent Units Restricted Stock Units Outstanding December 31, 2017 463,259 77,358 Granted 110,042 20,393 Paid (170,080 ) (28,023 ) Forfeited (7,350 ) (2,729 ) Outstanding December 31, 2018 395,871 66,999

Quarterly Results of Operatio_2

Quarterly Results of Operations (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) Years Ended December 31, (in thousands, except per share data) 2018 First Second Third Fourth Total Revenues $ 3,173,707 $ 3,195,908 $ 3,227,531 $ 3,278,518 Total benefits and expenses 3,035,782 2,948,620 2,904,870 3,140,572 Income before income taxes 137,925 247,288 322,661 137,946 Net Income 100,230 204,374 301,199 110,039 Earnings Per Share: Basic earnings per share $ 1.55 $ 3.19 $ 4.76 $ 1.75 Diluted earnings per share 1.52 3.13 4.68 1.72 2017 First Second Third Fourth Total Revenues $ 3,008,740 $ 3,129,276 $ 3,145,310 $ 3,232,443 Total benefits and expenses 2,800,896 2,789,961 2,805,148 2,976,949 Income before income taxes 207,844 339,315 340,162 255,494 Net Income 145,512 232,190 227,591 1,216,888 Earnings Per Share: Basic earnings per share $ 2.26 $ 3.60 $ 3.53 $ 18.89 Diluted earnings per share 2.22 3.54 3.47 18.49

Summary of Investments Other _2

Summary of Investments Other Than Investments in Related Parties (Tables)	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Summary Of Investments Other Than Investments In Related Parties [Table Text Block]	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE I-SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES December 31, 2018 (in millions) Type of Investment Amortized Cost Estimated Fair Value Amount at Which Shown in the Balance Sheets (1) Fixed maturity securities: United States government and government agencies and authorities $ 2,234 $ 2,186 $ 2,186 State and political subdivisions 721 752 752 Foreign governments (2) 6,449 7,635 7,635 Public utilities 2,876 2,909 2,909 Mortgage-backed and asset-backed securities 5,472 5,437 5,437 All other corporate bonds 21,130 21,073 21,073 Total fixed maturity securities $ 38,882 $ 39,992 $ 39,992 Equity securities $ 108 $ 82 $ 82 Mortgage loans on real estate 4,966 4,966 Policy loans 1,345 1,345 Funds withheld at interest 5,762 5,762 Short-term investments 143 143 Other invested assets 1,915 1,915 Total investments $ 53,121 $ 54,205 (1) Fixed maturity securities are classified as available-for-sale and carried at fair value. (2) Includes fixed maturities directly issued by foreign governments, supranational and foreign government-sponsored enterprises.

Condensed Financial Informati_2

Condensed Financial Information of The Registrant (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Statements [Table Text Block]	2018 2017 2016 CONDENSED BALANCE SHEETS Assets: Fixed maturity securities available-for-sale, at fair value $ 595,303 $ 710,303 Short-term and other investments 42,906 54,517 Cash and cash equivalents 20,641 15,176 Investment in subsidiaries 11,033,195 12,043,911 Loans to subsidiaries 1,010,000 1,010,000 Other assets 239,643 234,707 Total assets $ 12,941,688 $ 14,068,614 Liabilities and stockholders’ equity: Long-term debt - unaffiliated (1) $ 2,777,756 $ 2,775,579 Long-term debt - affiliated (2) 500,000 500,000 Other liabilities 1,213,379 1,223,500 Stockholders’ equity 8,450,553 9,569,535 Total liabilities and stockholders’ equity $ 12,941,688 $ 14,068,614 CONDENSED STATEMENTS OF INCOME Interest / dividend income (3) $ 575,833 $ 131,067 $ 602,830 Investment related gains (losses), net (5,392 ) (5,187 ) 203 Operating expenses (35,912 ) (20,517 ) (20,742 ) Interest expense (181,364 ) (177,417 ) (168,924 ) Income (loss) before income tax and undistributed earnings of subsidiaries 353,165 (72,054 ) 413,367 Income tax expense (benefit) (37,294 ) 65,882 (23,911 ) Net income (loss) before undistributed earnings of subsidiaries 390,459 (137,936 ) 437,278 Equity in undistributed earnings of subsidiaries 325,383 1,960,117 264,165 Net income 715,842 1,822,181 701,443 Other comprehensive income (loss) 21,455 (7,672 ) 5,531 Total comprehensive income $ 737,297 $ 1,814,509 $ 706,974 The condensed financial information of RGA (the “Parent Company”) should be read in conjunction with the consolidated financial statements of RGA and its subsidiaries and the notes thereto (the “Consolidated Financial Statements”). These condensed unconsolidated financial statements reflect the results of operations, financial position and cash flows for RGA. Investments in subsidiaries are accounted for using the equity method of accounting. (1) Long-term debt - unaffiliated consists of the following: 2018 2017 $400 million 6.45% Senior Notes due 2019 $ 399,941 $ 399,873 $400 million 5.00% Senior Notes due 2021 399,466 399,245 $400 million 4.70% Senior Notes due 2023 399,289 399,138 $400 million 3.95% Senior Notes due 2026 399,987 399,987 $400 million 6.20% Subordinated Debentures due 2042 400,000 400,000 $400 million 5.75% Subordinated Debentures due 2056 400,000 400,000 $400 million Variable Rate Junior Subordinated Debentures due 2065 398,674 398,670 Subtotal 2,797,357 2,796,913 Unamortized debt issue costs (19,601 ) (21,334 ) Total $ 2,777,756 $ 2,775,579 Repayments of long-term debt—unaffiliated due over the next five years total $400,000 in 2019, $400,000 in 2021 and $400,000 in 2023. (2) Long-term debt—affiliated in 2018 and 2017 and consists of $500,000 of subordinated debt issued to various operating subsidiaries. (3) Interest/dividend income includes $450,000 and $478,602 of cash dividends received from consolidated subsidiaries in 2018 and 2016, respectively. In 2017 there were no cash dividends received from consolidated subsidiaries. REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE II—CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT (continued) December 31, (in thousands) 2018 2017 2016 CONDENSED STATEMENTS OF CASH FLOWS Operating activities: Net income $ 715,842 $ 1,822,181 $ 701,443 Equity in earnings of subsidiaries (325,383 ) (1,960,117 ) (264,165 ) Other, net 36,754 57,677 (63,795 ) Net cash (used in) provided by operating activities 427,213 (80,259 ) 373,483 Investing activities: Sales of fixed maturity securities available-for-sale 482,324 514,508 228,383 Purchases of fixed maturity securities available-for-sale (383,392 ) (75,000 ) (984,397 ) Repayments/issuances of loans to subsidiaries — 40,000 20,000 Change in short-term investments — — 102,508 Change in other invested assets 44 125,506 (109,914 ) Capital contributions to subsidiaries (82,150 ) (62,500 ) (314,142 ) Net cash (used in) provided by investing activities 16,826 542,514 (1,057,562 ) Financing activities: Dividends to stockholders (140,110 ) (117,291 ) (100,371 ) Purchases of treasury stock (299,679 ) (43,508 ) (122,916 ) Exercise of stock options, net 3,459 7,292 15,321 Net change in cash collateral for loaned securities (2,244 ) (37,290 ) 105,093 Principal payments on debt — (300,000 ) — Proceeds from unaffiliated long-term debt issuance — — 799,984 Debt issuance costs — — (8,766 ) Net cash (used in) provided by financing activities (438,574 ) (490,797 ) 688,345 Net change in cash and cash equivalents 5,465 (28,542 ) 4,266 Cash and cash equivalents at beginning of year 15,176 43,718 39,452 Cash and cash equivalents at end of year $ 20,641 $ 15,176 $ 43,718 Supplementary information: Cash paid for interest $ 176,236 $ 185,554 $ 169,860 Cash paid for income taxes, net of refunds $ 93,000 $ 8,248 $ 1,500

Supplementary Insurance Infor_2

Supplementary Insurance Information (Tables)	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Supplementary Insurance Information For Insurance Companies Disclosure [Table Text Block]	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE III—SUPPLEMENTARY INSURANCE INFORMATION (in thousands) As of December 31, Deferred Policy Acquisition Costs Future Policy Benefits and Interest-Sensitive Contract Liabilities Other Policy Claims and Benefits Payable 2018 U.S. and Latin America: Traditional $ 1,824,874 $ 11,727,505 $ 1,948,335 Financial Solutions 420,154 19,420,906 20,855 Canada: Traditional 192,661 2,929,568 182,343 Financial Solutions — 25,574 34,471 Europe, Middle East and Africa: Traditional 239,161 1,110,194 977,530 Financial Solutions — 4,540,751 34,514 Asia Pacific: Traditional 702,439 1,738,199 2,436,473 Financial Solutions 18,481 1,043,375 2,365 Corporate and Other — 753,854 5,869 Total $ 3,397,770 $ 43,289,926 $ 5,642,755 2017 U.S. and Latin America: Traditional $ 1,818,572 $ 11,343,921 $ 1,814,018 Financial Solutions 405,623 15,127,529 17,876 Canada: Traditional 212,345 3,041,790 206,655 Financial Solutions — 27,908 1,040 Europe, Middle East and Africa: Traditional 229,150 1,075,786 882,744 Financial Solutions — 4,741,983 38,044 Asia Pacific: Traditional 552,947 1,611,633 2,017,920 Financial Solutions 21,187 1,118,012 6,885 Corporate and Other — 502,321 6,892 Total $ 3,239,824 $ 38,590,883 $ 4,992,074 REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE III—SUPPLEMENTARY INSURANCE INFORMATION (continued) (in thousands) Year ended December 31, Premium Income Net Investment Income Policyholder Benefits and Interest Credited Amortization of DAC Other Expenses (1) 2018 U.S. and Latin America: Traditional $ 5,533,256 $ 729,757 $ 5,130,795 $ 180,407 $ 698,121 Financial Solutions 27,203 706,624 442,071 108,697 105,999 Canada: Traditional 1,024,021 199,412 847,828 13,097 251,171 Financial Solutions 43,372 1,334 36,808 — 2,204 Europe, Middle East and Africa: Traditional 1,423,199 66,242 1,233,458 26,915 179,113 Financial Solutions 195,333 133,855 116,492 — 37,007 Asia Pacific: Traditional 2,296,435 95,521 1,885,355 92,231 261,761 Financial Solutions 866 40,729 39,726 1,691 19,028 Corporate and Other 91 165,051 11,600 — 308,269 Total $ 10,543,776 $ 2,138,525 $ 9,744,133 $ 423,038 $ 1,862,673 2017 U.S. and Latin America: Traditional $ 5,356,321 $ 728,073 $ 4,842,412 $ 191,725 $ 692,600 Financial Solutions 23,683 778,473 458,368 185,280 105,146 Canada: Traditional 901,976 189,018 757,912 12,426 212,964 Financial Solutions 38,229 5,115 29,639 — 2,656 Europe, Middle East and Africa: Traditional 1,301,640 55,511 1,096,211 20,570 174,808 Financial Solutions 163,720 123,258 153,874 — 33,683 Asia Pacific: Traditional 2,053,029 91,675 1,635,728 91,477 334,695 Financial Solutions 2,419 34,529 40,467 1,388 18,790 Corporate and Other 113 148,999 6,346 — 273,789 Total $ 9,841,130 $ 2,154,651 $ 9,020,957 $ 502,866 $ 1,849,131 2016 U.S. and Latin America: Traditional $ 5,249,571 $ 699,833 $ 4,717,850 $ 177,255 $ 698,762 Financial Solutions 24,349 631,097 333,107 133,501 90,458 Canada: Traditional 928,642 178,927 707,428 10,621 265,250 Financial Solutions 38,701 2,692 36,275 — 2,718 Europe, Middle East and Africa: Traditional 1,140,062 50,301 999,005 33,795 132,290 Financial Solutions 180,271 125,282 178,014 — 24,497 Asia Pacific: Traditional 1,681,505 83,049 1,345,951 24,597 286,674 Financial Solutions 5,428 23,648 37,976 1,423 19,920 Corporate and Other 342 117,057 2,460 — 217,738 Total $ 9,248,871 $ 1,911,886 $ 8,358,066 $ 381,192 $ 1,738,307 (1) Includes policy acquisition costs and other insurance expenses, excluding amortization of DAC. Also includes other operating expenses, interest expense, and collateral finance and securitization expense.

Supplemental Schedule of Rein_2

Supplemental Schedule of Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Supplemental Schedule Of Reinsurance Premiums For Insurance Companies [Table Text Block]	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE IV—REINSURANCE (in millions) As of or for the Year ended December 31, Gross Amount Ceded to Other Companies Assumed from Other Companies Net Amounts Percentage of Amount Assumed to Net 2018 Life insurance in force $ 1,363 $ 186,172 $ 3,329,181 $ 3,144,372 105.9 % Premiums U.S. and Latin America: Traditional $ 31.6 $ 593.7 $ 6,095.4 5,533.3 110.2 % Financial Solutions 4.7 — 22.5 27.2 82.7 Canada: Traditional — 46.9 1,070.9 1,024.0 104.6 Financial Solutions — — 43.4 43.4 100.0 Europe, Middle East and Africa: Traditional 26.0 25.9 1,423.1 1,423.2 100.0 Financial Solutions 0.2 143.7 338.8 195.3 173.5 Asia Pacific: Traditional — 49.8 2,346.2 2,296.4 102.2 Financial Solutions — — 0.9 0.9 100.0 Corporate and Other — — 0.1 0.1 100.0 Total $ 62.5 $ 860.0 $ 11,341.3 $ 10,543.8 107.6 2017 Life insurance in force $ 1,462 $ 205,529 $ 3,297,275 $ 3,093,208 106.6 % Premiums U.S. and Latin America: Traditional $ 30.5 $ 610.4 $ 5,936.2 $ 5,356.3 110.8 % Financial Solutions 4.3 — 19.4 23.7 81.9 Canada: Traditional — 38.1 940.1 902.0 104.2 Financial Solutions — — 38.2 38.2 100.0 Europe, Middle East and Africa: Traditional 26.6 34.9 1,310.0 1,301.7 100.6 Financial Solutions 0.2 125.0 288.5 163.7 176.2 Asia Pacific: Traditional — 54.5 2,107.5 2,053.0 102.7 Financial Solutions — — 2.4 2.4 100.0 Corporate and Other — — 0.1 0.1 100.0 Total $ 61.6 $ 862.9 $ 10,642.4 $ 9,841.1 108.1 2016 Life insurance in force $ 1,576 $ 214,727 $ 3,062,525 $ 2,849,374 107.5 % Premiums U.S. and Latin America: Traditional $ 31.6 $ 616.0 $ 5,834.0 $ 5,249.6 111.1 % Financial Solutions 1.6 40.2 63.0 24.4 258.2 Canada: Traditional — 36.5 965.1 928.6 103.9 Financial Solutions — — 38.7 38.7 100.0 Europe, Middle East and Africa: Traditional 24.1 30.9 1,146.9 1,140.1 100.6 Financial Solutions 0.3 84.4 264.4 180.3 146.6 Asia Pacific: Traditional — 50.3 1,731.8 1,681.5 103.0 Financial Solutions — — 5.4 5.4 100.0 Corporate and Other — — 0.3 0.3 100.0 Total $ 57.6 $ 858.3 $ 10,049.6 $ 9,248.9 108.7

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Tables)	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation And Qualifying Accounts [Table Text Block]	REINSURANCE GROUP OF AMERICA, INCORPORATED SCHEDULE V—VALUATION AND QUALIFYING ACCOUNTS (in millions) Additions Description Balance at Beginning of Period Charged to Costs and Expenses Charged to Other Accounts Deductions Balance at End of Period 2018 Valuation allowance for deferred income taxes $ 226.9 $ (33.7 ) $ (12.1 ) $ — $ 181.1 Valuation allowance for mortgage loans 9.4 1.9 — — 11.3 2017 Valuation allowance for deferred income taxes $ 133.4 $ 88.5 $ 10.6 $ 5.6 $ 226.9 Valuation allowance for mortgage loans 7.7 1.7 — — 9.4 2016 Valuation allowance for deferred income taxes $ 127.1 $ 11.0 $ (4.7 ) $ — $ 133.4 Valuation allowance for mortgage loans 6.8 0.9 — — 7.7

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Collateral Obtained Percent Of Fair Value Reverse Repurchase Agreements	100.00%
Property, Plant and Equipment, Useful Life	40 years
Other Asset Impairment Charges	$ 4.7	$ 24.5	$ 0.6
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	97	79.4
Property, Plant and Equipment, Gross	248.7	236.1
Depreciation	18.3	17.2	16.6
Goodwill	7	7
Present Value of Future Insurance Profits, Net	5.1	3.3
Present Value of Future Insurance Profits, Accumulated Amortization	15	14.6
Amortization of Value of Business Acquired (VOBA)	0.4	0.3	0.5
Values Of Business Acquired Distribution Agreements And Customer Relationships	40.8	49.2
Accumulated Amortization Of Values Of Business Acquired Distribution Agreements And Customer Relationships	79.8	71.5
Amortization Of Values Of Business Acquired Distribution Agreements And Customer Relationships	8.3	8.7	9
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	8.1
Finite-Lived Intangible Assets, Amortization Expense, Year Two	7.6
Finite-Lived Intangible Assets, Amortization Expense, Year Three	6.6
Finite-Lived Intangible Assets, Amortization Expense, Year Four	6.4
Finite-Lived Intangible Assets, Amortization Expense, Year Five	6.2
Capitalized Computer Software, Net	150.4	145.5
Capitalized Computer Software, Amortization	$ 26.9	$ 35.7	$ 10.3
Value of Customer Relationships Acquired [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Value of Distribution Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years

Summary of Significant Accoun_4

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Future Policy Benefits) (Narrative) (Details)	Dec. 31, 2018
Maximum [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Long-Duration Contracts, Assumptions by Product and Guarantee, Discount Rate	6.00%
Minimum [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Long-Duration Contracts, Assumptions by Product and Guarantee, Discount Rate	3.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Intangible Assets) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization Of Values Of Business Acquired Distribution Agreements And Customer Relationships	$ 79.8	$ 71.5
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	8.1
Finite-Lived Intangible Assets, Amortization Expense, Year Two	7.6
Finite-Lived Intangible Assets, Amortization Expense, Year Three	6.6
Finite-Lived Intangible Assets, Amortization Expense, Year Four	6.4
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 6.2
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Finite-lived Intangible Assets Acquired	$ 37.4	3.1
Accumulated Amortization Of Values Of Business Acquired Distribution Agreements And Customer Relationships	4.4	0.6
Amortization of Intangible Assets	3.8	$ 0.3	$ 0.2
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	4.2
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4.2
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4.1
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4.1
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 4.1

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (New Accounting Pronouncements) (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle		$ 17,700
Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Amount	$ 6,103	10,532	$ 0
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(2,600)	(156,400)
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(55,200)
Accounting Standards Update 2018 02 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	2,020	(17,723)
AOCI Attributable to Parent [Member] | Accounting Standards Update 2018 02 [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 2,573	$ (156,372)

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Earnings Per Share Basic and Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to Parent	$ 110,039	$ 301,199	$ 204,374	$ 100,230	$ 1,216,888	$ 227,591	$ 232,190	$ 145,512	$ 715,842	$ 1,822,181	$ 701,443
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted Average Number of Shares Outstanding, Basic									63,658	64,427	64,274
Equivalent shares from outstanding stock options									1,436	1,326	715
Weighted Average Number of Shares Outstanding, Diluted									65,094	65,753	64,989
Earnings per share
Earnings Per Share, Basic (in dollars per share)	$ 1.75	$ 4.76	$ 3.19	$ 1.55	$ 18.89	$ 3.53	$ 3.60	$ 2.26	$ 11.25	$ 28.28	$ 10.91
Earnings Per Share, Diluted (in dollars per share)	$ 1.72	$ 4.68	$ 3.13	$ 1.52	$ 18.49	$ 3.47	$ 3.54	$ 2.22	$ 11	$ 27.71	$ 10.79

Earnings Per Share Earnings Per

Earnings Per Share Earnings Per Share (Narrative) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.1	0.2	0
Contingently Issuable Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.4	0.3	0.4

Investments (Investments in Fix

Investments (Investments in Fixed Maturity and Equity Securities Available-for-Sale by Sector) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 24,006,407	$ 21,966,803
Available-for-sale Securities	23,982,119	23,210,968
Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	38,882,168	35,281,412
Available-for-sale Securities, Gross Unrealized Gains	1,858,668	2,982,754
Available-for-sale Securities, Gross Unrealized Losses	748,490	113,346
Available-for-sale Securities	$ 39,992,346	$ 38,150,820
Percentage Of Total Available For Sale Securities	100.00%	100.00%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 275	$ 275
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis		102,841
Available-for-sale Securities, Gross Unrealized Gains		958
Available-for-sale Securities, Gross Unrealized Losses		3,647
Available-for-sale Securities		$ 100,152
Percentage Of Total Available For Sale Securities		100.00%
Corporate Debt Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	24,006,407	$ 21,966,803
Available-for-sale Securities, Gross Unrealized Gains	530,804	1,299,594
Available-for-sale Securities, Gross Unrealized Losses	555,092	55,429
Available-for-sale Securities	$ 23,982,119	$ 23,210,968
Percentage Of Total Available For Sale Securities	59.90%	60.90%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
Canadian Provincial Governments [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,768,466	2,843,273
Available-for-sale Securities, Gross Unrealized Gains	1,126,227	1,378,510
Available-for-sale Securities, Gross Unrealized Losses	2,308	1,707
Available-for-sale Securities	$ 3,892,385	$ 4,220,076
Percentage Of Total Available For Sale Securities	9.70%	11.10%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
Residential Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,872,236	1,695,126
Available-for-sale Securities, Gross Unrealized Gains	22,267	36,632
Available-for-sale Securities, Gross Unrealized Losses	25,282	11,878
Available-for-sale Securities	$ 1,869,221	$ 1,719,880
Percentage Of Total Available For Sale Securities	4.70%	4.50%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
Asset-backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,171,254	1,634,758
Available-for-sale Securities, Gross Unrealized Gains	10,779	18,798
Available-for-sale Securities, Gross Unrealized Losses	32,829	5,194
Available-for-sale Securities	$ 2,149,204	$ 1,648,362
Percentage Of Total Available For Sale Securities	5.40%	4.30%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 275	$ 275
Commercial Mortgage Backed Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,428,115	1,285,594
Available-for-sale Securities, Gross Unrealized Gains	9,153	22,627
Available-for-sale Securities, Gross Unrealized Losses	18,234	4,834
Available-for-sale Securities	$ 1,419,034	$ 1,303,387
Percentage Of Total Available For Sale Securities	3.50%	3.40%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
US Treasury and Government [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,233,537	1,953,436
Available-for-sale Securities, Gross Unrealized Gains	10,204	12,089
Available-for-sale Securities, Gross Unrealized Losses	57,867	21,933
Available-for-sale Securities	$ 2,185,874	$ 1,943,592
Percentage Of Total Available For Sale Securities	5.50%	5.10%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
US States and Political Subdivisions Debt Securities [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	721,290	647,727
Available-for-sale Securities, Gross Unrealized Gains	39,914	59,997
Available-for-sale Securities, Gross Unrealized Losses	9,010	4,296
Available-for-sale Securities	$ 752,194	$ 703,428
Percentage Of Total Available For Sale Securities	1.90%	1.80%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
Debt Security, Government, Non-US [Member] | Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	3,680,863	3,254,695
Available-for-sale Securities, Gross Unrealized Gains	109,320	154,507
Available-for-sale Securities, Gross Unrealized Losses	47,868	8,075
Available-for-sale Securities	$ 3,742,315	$ 3,401,127
Percentage Of Total Available For Sale Securities	9.40%	8.90%
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities	$ 0	$ 0
Nonredeemable Preferred Stock [Member] | Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis		41,553
Available-for-sale Securities, Gross Unrealized Gains		479
Available-for-sale Securities, Gross Unrealized Losses		2,226
Available-for-sale Securities		$ 39,806
Percentage Of Total Available For Sale Securities		39.70%
Equity Securities Other Than Non-redeemable Preferred Stock [Member] | Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis		$ 61,288
Available-for-sale Securities, Gross Unrealized Gains		479
Available-for-sale Securities, Gross Unrealized Losses		1,421
Available-for-sale Securities		$ 60,346
Percentage Of Total Available For Sale Securities		60.30%

Investments (Fixed Maturity Sec

Investments (Fixed Maturity Securities Pledged And Received As Collateral) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 24,006,407	$ 21,966,803
Available-for-sale Securities	23,982,119	23,210,968
Assets Held-in-trust	767,900	841,500
Estimate of Fair Value Measurement [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held-in-trust	20,366,170	16,715,281
Reported Value Measurement [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held-in-trust	20,072,735	15,584,296
Collateral Fixed Maturity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	80,891	72,542
Available-for-sale Securities	83,950	75,622
Collateral Received Fixed Maturity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	$ 616,584	$ 590,417

Investments (Exposure To Concen

Investments (Exposure To Concentrations Of Credit Risk) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 24,006,407	$ 21,966,803
Available-for-sale Securities	23,982,119	23,210,968
Canadian Province Of Ontario Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,091,018	1,119,337
Available-for-sale Securities	1,757,087	1,917,996
Canadian Province Of Quebec Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	913,642	939,837
Available-for-sale Securities	$ 1,187,526	$ 1,282,944

Investments (Amortized Cost and

Investments (Amortized Cost and Fair Value of Fixed Maturities by Contractual Maturities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis	$ 1,185,868
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis	8,760,200
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis	9,060,972
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	14,403,523
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	5,471,605
Available for Sale at Fair value - Amortized cost	38,882,168	$ 35,281,412
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value	1,190,931
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value	8,851,307
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value	9,149,497
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	15,363,152
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	5,437,459
Fixed maturity securities available-for-sale	$ 39,992,346	$ 38,150,820

Investments (Amortized Cost a_2

Investments (Amortized Cost and Fair Value of Fixed Maturity Holdings by Industry Type) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Corporate Secturities by Investment Sector And Credit Rating [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 24,006,407	$ 21,966,803
Available-for-sale Securities	$ 23,982,119	$ 23,210,968
Percentage Of Total Available For Sales Securities	100.00%	100.00%
Financial Services Sector [Member]
Corporate Secturities by Investment Sector And Credit Rating [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 8,793,742	$ 7,977,885
Available-for-sale Securities	$ 8,730,568	$ 8,362,774
Percentage Of Total Available For Sales Securities	36.30%	36.10%
Commercial and Industrial Sector [Member]
Corporate Secturities by Investment Sector And Credit Rating [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 12,336,857	$ 11,535,166
Available-for-sale Securities	$ 12,342,111	$ 12,199,333
Percentage Of Total Available For Sales Securities	51.60%	52.50%
Utility Industry [Member]
Corporate Secturities by Investment Sector And Credit Rating [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 2,875,808	$ 2,453,752
Available-for-sale Securities	$ 2,909,440	$ 2,648,861
Percentage Of Total Available For Sales Securities	12.10%	11.40%

Investments (Credit Losses Reco

Investments (Credit Losses Recognized in Earnings on Fixed Maturity Securities Held by the Company) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 3,677	$ 6,013	$ 7,284
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses	0	0	231
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Change in Status	0	(2,336)	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold	0	0	(1,502)
Balance, end of period	$ 3,677	$ 3,677	$ 6,013

Investments (Fair Value Below A

Investments (Fair Value Below Amortized Cost of Gross Unrealized Losses for Fixed Maturity and Equity Securities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Gross unrealized losses with number of securities [Line Items]
Available-for-sale Securities, Gross Unrealized Losses	$ 748,490	$ 116,993
Percentage Of Total Gross Unrealized Losses	100.00%	100.00%
Less Than 20 Percent [Member]
Gross unrealized losses with number of securities [Line Items]
Available-for-sale Securities, Gross Unrealized Losses	$ 721,015	$ 113,466
Percentage Of Total Gross Unrealized Losses	96.30%	97.00%
More Than Or Equal To 20 Percent For Less Than Six Months [Member]
Gross unrealized losses with number of securities [Line Items]
Available-for-sale Securities, Gross Unrealized Losses	$ 21,336	$ 689
Percentage Of Total Gross Unrealized Losses	2.90%	0.60%
More Than Or Equal To 20 Percent For Six Months Or Greater [Member]
Gross unrealized losses with number of securities [Line Items]
Available-for-sale Securities, Gross Unrealized Losses	$ 6,139	$ 2,838
Percentage Of Total Gross Unrealized Losses	0.80%	2.40%

Investments (Fair Value and Los

Investments (Fair Value and Losses by Investment Category and Length of Time in a Loss Position) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 12,073,860	$ 4,565,273
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	408,581	40,239
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	7,226,996	2,738,393
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	339,909	73,107
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	19,300,856	7,303,666
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	748,490	113,346
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	11,189,013	4,339,799
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	360,213	36,789
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	7,093,099	2,644,670
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	324,612	65,548
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	18,282,112	6,984,469
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	684,825	102,337
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	8,505,371	1,886,212
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	302,604	17,099
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	3,611,266	1,009,750
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	195,082	28,080
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	12,116,637	2,895,962
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	497,686	45,179
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | Canadian Provincial Governments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	25,169	18,688
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	419	91
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	131,806	111,560
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	1,612	1,596
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	156,975	130,248
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	2,031	1,687
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	269,558	566,699
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	2,488	5,852
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	836,741	224,439
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	22,760	6,004
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,106,299	791,138
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	25,248	11,856
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,102,677	434,274
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	24,271	2,707
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	381,609	168,524
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	8,523	2,434
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,484,286	602,798
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	32,794	5,141
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	384,259	220,401
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	4,304	1,914
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	414,719	103,269
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	13,930	2,920
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	798,978	323,670
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	18,234	4,834
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	8,616	800,298
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	80	6,177
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,086,694	767,197
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	57,787	15,756
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,095,310	1,567,495
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	57,867	21,933
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	103,504	43,510
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	1,538	242
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	157,330	68,666
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	7,472	4,054
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	260,834	112,176
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	9,010	4,296
Fixed Maturities [Member] | External Credit Rating, Investment Grade [Member] | Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	789,859	369,717
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	24,509	2,707
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	472,934	191,265
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	17,446	4,704
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,262,793	560,982
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	41,955	7,411
Fixed Maturities [Member] | External Credit Rating, Non Investment Grade [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	884,847	225,474
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	48,368	3,450
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	133,897	93,723
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	15,297	7,559
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,018,744	319,197
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	63,665	11,009
Fixed Maturities [Member] | External Credit Rating, Non Investment Grade [Member] | Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	755,679	194,879
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	42,760	3,317
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	122,559	75,731
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	14,646	6,933
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	878,238	270,610
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	57,406	10,250
Fixed Maturities [Member] | External Credit Rating, Non Investment Grade [Member] | Canadian Provincial Governments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	443	1,995
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	34	20
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,770	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	243	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,213	1,995
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	277	20
Fixed Maturities [Member] | External Credit Rating, Non Investment Grade [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,026	1,369
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	34	22
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,026	1,369
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	34	22
Fixed Maturities [Member] | External Credit Rating, Non Investment Grade [Member] | Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,063	1,489
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	35	53
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,063	1,489
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	35	53
Fixed Maturities [Member] | External Credit Rating, Non Investment Grade [Member] | Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	128,725	28,600
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	5,574	113
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	7,479	15,134
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	339	551
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	136,204	43,734
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ 5,913	664
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		5,902
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1,024
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		73,722
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		2,623
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		79,624
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses		3,647
Equity Securities [Member] | Nonredeemable Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		82
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		26,471
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		2,225
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		26,553
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses		2,226
Equity Securities [Member] | Equity Securities Other Than Non-redeemable Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		5,820
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1,023
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		47,251
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		398
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		53,071
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses		$ 1,421

Investments (Investment Income

Investments (Investment Income Net of Related Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	$ 2,229,031	$ 2,235,362	$ 1,983,975
Investment Income, Investment Expense	(90,506)	(80,711)	(72,089)
Investment income, net of related expenses	2,138,525	2,154,651	1,911,886
Available-for-sale Securities [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	1,528,086	1,401,585	1,285,406
Equity Securities [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	4,343	4,445	12,513
Mortgage Loans on Real Estate [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	214,387	197,755	168,582
Policy Loans [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	59,332	60,617	63,837
Funds Withheld At Interest [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	309,977	457,774	368,728
Short-term Investments [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	14,349	7,171	8,051
Other Aggregated Investments [Member]
Major Categories Of Investment Income Net Of Expenses [Line Items]
Gross Investment Income, Operating	$ 98,557	$ 106,015	$ 76,858

Investments (Investment Related

Investments (Investment Related Gains (Losses) Net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Securities, Available-for-sale [Abstract]
Other than Temporary Impairment Losses, Investments	$ (28,494)	$ (42,639)	$ (38,805)
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest	0	0	74
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	1,202	0
Available-for-sale Securities, Realized Losses, Excluding Other than Temporary Impairments	(158,870)	(37,328)	(47,094)
Available-for-sale Securities, Gross Realized Gains	65,211	110,546	145,172
Available-for-sale Equity Securities, Gross Unrealized Gain	4,429	23	9,198
Other Impairment Losses And Change In Mortgage Loan Provision	(11,919)	(9,497)	(11,006)
Derivatives And Other Investments Net	(15,324)	152,328	39,527
Available-for-sale Equity Securities, Gross Unrealized Loss	(1,937)	(4,351)	(2,871)
Gain (Loss) on Sale of Equity Investments	(23,184)	0	0
Realized Investment Gains (Losses)	$ (170,088)	$ 167,880	$ 94,195

Investments (Borrowed Securitie

Investments (Borrowed Securities Repurchased Securities And Repurchased Reversed Repurchased Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Securities Received as Collateral	$ 112,000	$ 128,000
Securities for Reverse Repurchase Agreements	554,806	413,819
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	530,932	417,550
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	28,600	31,200
Estimate of Fair Value Measurement [Member]
Debt Securities, Available-for-sale [Line Items]
Securities Borrowed	366,663	377,820
Securities Loaned, Fair Value of Collateral	102,618	121,551
Securities for Reverse Repurchase Agreements	554,589	428,344
Reported Value Measurement [Member]
Debt Securities, Available-for-sale [Line Items]
Securities Borrowed	335,781	358,875
Securities Loaned, Fair Value of Collateral	$ 101,981	$ 117,246

Investments (Securities Pledged

Investments (Securities Pledged as Collateral Related to Repurchase Reverse Repurchase Program) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	$ 102,618	$ 121,551
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	554,589	428,344
Securities Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	671,492	576,786
Secured Borrowings, Gross, Difference, Amount	14,285	26,891
Obligation to Return Securities Received as Collateral	657,207	549,895
Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	1,131
Obligation to Return Securities Received as Collateral	0	1,131
Maturity Less than 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
Obligation to Return Securities Received as Collateral	0	0
Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	312
Obligation to Return Securities Received as Collateral	0	312
Maturity Greater than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	102,618	121,551
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	554,589	426,901
Obligation to Return Securities Received as Collateral	657,207	548,452
Corporate Debt Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	102,618	121,551
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	254,151	184,646
Corporate Debt Securities [Member] | Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
Corporate Debt Securities [Member] | Maturity Less than 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
Corporate Debt Securities [Member] | Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	0	0
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	312
Corporate Debt Securities [Member] | Maturity Greater than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	102,618	121,551
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	254,151	184,334
US Government Agencies Debt Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	221,572	220,765
US Government Agencies Debt Securities [Member] | Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
US Government Agencies Debt Securities [Member] | Maturity Less than 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
US Government Agencies Debt Securities [Member] | Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
US Government Agencies Debt Securities [Member] | Maturity Greater than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	221,572	220,765
Debt Security, Government, Non-US [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	78,866	21,802
Debt Security, Government, Non-US [Member] | Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
Debt Security, Government, Non-US [Member] | Maturity Less than 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
Debt Security, Government, Non-US [Member] | Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	0	0
Debt Security, Government, Non-US [Member] | Maturity Greater than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	$ 78,866	21,802
Other Debt Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		1,131
Other Debt Obligations [Member] | Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		1,131
Other Debt Obligations [Member] | Maturity Less than 30 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		0
Other Debt Obligations [Member] | Maturity 30 to 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		0
Other Debt Obligations [Member] | Maturity Greater than 90 Days [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		$ 0

Investments (Mortgage Loans by

Investments (Mortgage Loans by Property Type) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 4,983,354	$ 4,413,171
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	100.00%	100.00%
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ (5,770)	$ (3,254)
Allowance for Loan and Lease Losses, Real Estate	(11,286)	(9,384)	$ (7,685)	$ (6,813)
Mortgage loans on real estate	4,966,298	4,400,533
Office Building [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 1,725,748	$ 1,487,392
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	34.60%	33.60%
Retail Site [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 1,432,394	$ 1,270,676
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	28.70%	28.80%
Industrial Property [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 961,924	$ 938,612
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	19.30%	21.30%
Apartment Building [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 571,291	$ 510,052
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	11.50%	11.60%
Other Property [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 291,997	$ 206,439
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	5.90%	4.70%

Investments (Mortgage Loans b_2

Investments (Mortgage Loans by Maturity Date) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 4,983,354	$ 4,413,171
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	100.00%	100.00%
Mortgage Loans On Real Estate Due One Year Through Five Years [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 1,425,598	$ 1,091,066
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	28.60%	24.80%
Mortgage Loans On Real Estate Due After Five Years [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 2,686,264	$ 2,516,872
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	53.90%	57.00%
Mortgage Loans On Real Estate Due After Ten Years [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 871,492	$ 805,233
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	17.50%	18.20%

Investments (Mortgage Loans b_3

Investments (Mortgage Loans by Credit Quality Indicator) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 4,983,354	$ 4,413,171
Loans Receivable, Gross, Commercial, Construction	$ 32,620	$ 9,686
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	100.00%	100.00%
Greater than 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 4,561,177	$ 4,182,753
1.00x - 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	233,260	151,281
Less than 1.00x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	156,297	69,451
0% - 59.99%
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	2,523,670	2,206,208
Loans Receivable, Gross, Commercial, Construction	$ 13,691	$ 0
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	50.60%	50.00%
0% - 59.99% | Greater than 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 2,410,556	$ 2,148,428
0% - 59.99% | 1.00x - 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	61,246	53,979
0% - 59.99% | Less than 1.00x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	38,177	3,801
60% - 69.99%
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	1,749,331	1,608,078
Loans Receivable, Gross, Commercial, Construction	$ 18,929	$ 0
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	35.10%	36.40%
60% - 69.99% | Greater than 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 1,618,374	$ 1,517,029
60% - 69.99% | 1.00x - 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	73,908	47,128
60% - 69.99% | Less than 1.00x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	38,120	43,921
70% - 79.99%
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	517,147	431,274
Loans Receivable, Gross, Commercial, Construction	$ 0	$ 0
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	10.40%	9.80%
70% - 79.99% | Greater than 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 414,269	$ 396,446
70% - 79.99% | 1.00x - 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	48,438	19,461
70% - 79.99% | Less than 1.00x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	54,440	15,367
Greater than 80%
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	193,206	167,611
Loans Receivable, Gross, Commercial, Construction	$ 0	$ 9,686
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	3.90%	3.80%
Greater than 80% | Greater than 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 117,978	$ 120,850
Greater than 80% | 1.00x - 1.20x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	49,668	30,713
Greater than 80% | Less than 1.00x
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 25,560	$ 6,362

Investments (Mortgage Loans Age

Investments (Mortgage Loans Age Analysis) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	$ 4,983,354	$ 4,413,171
Financing Receivable, Recorded Investment, Current	4,983,354	4,394,015
Financing Receivable, Recorded Investment, Past Due	0	19,156
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	17,100
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 0	$ 2,056

Investments (Mortgage Loans b_4

Investments (Mortgage Loans by Method of Evaluation and Related Valuation Allowances) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage Loans [Abstract]
Financing Receivable, Individually Evaluated for Impairment	$ 30,635	$ 5,858
Financing Receivable, Collectively Evaluated for Impairment	4,952,719	4,407,313
Loans Receivable, Gross, Commercial, Real Estate	4,983,354	4,413,171
Valuation Allowances [Abstract]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	11,286	9,384
Allowance for Loan and Lease Losses, Real Estate	$ 11,286	$ 9,384	$ 7,685	$ 6,813

Investments (Loan Valuation All

Investments (Loan Valuation Allowance for Mortgage Loans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance beginning	$ 9,384	$ 7,685	$ 6,813
Provision	1,918	1,691	872
SEC Schedule, 12-09, Valuation Allowances and Reserves, Increase (Decrease) Adjustment	(16)	8	0
Balance ending	$ 11,286	$ 9,384	$ 7,685

Investments (Impaired Mortgage

Investments (Impaired Mortgage Loans) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		$ 30,660	$ 6,427
Impaired Financing Receivable, Recorded Investment		30,635	5,858
Impaired Financing Receivable, Related Allowance		0	0
Impaired Financing Receivable Net Of Related Allowance		30,635	5,858
Impaired Financing Receivable, Average Recorded Investment	[1]	24,240	3,621	$ 2,249
Impaired Financing Receivable, Interest Income, Accrual Method		1,129	186	142
Impaired mortgage loans with no valuation allowance recorded
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		30,660	6,427
Impaired Financing Receivable, Recorded Investment		30,635	5,858
Impaired Financing Receivable, Related Allowance		0	0
Impaired Financing Receivable Net Of Related Allowance		30,635	5,858
Impaired Financing Receivable, Average Recorded Investment	[1]	24,240	3,621	2,249
Impaired Financing Receivable, Interest Income, Accrual Method		1,129	186	142
Impaired mortgage loans with valuation allowance recorded
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		0	0
Impaired Financing Receivable, Recorded Investment		0	0
Impaired Financing Receivable, Related Allowance		0	0
Impaired Financing Receivable Net Of Related Allowance		0	0
Impaired Financing Receivable, Average Recorded Investment	[1]	0	0	0
Impaired Financing Receivable, Interest Income, Accrual Method		$ 0	$ 0	$ 0
[1]	Average recorded investment represents the average loan balances as of the beginning of period and all subsequent quarterly end of period balances.

Investments (Other Invested Ass

Investments (Other Invested Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Investments [Abstract]
Other invested assets	$ 1,915,297	$ 1,505,332
Limited Partner [Member]
Other Investments [Abstract]
Other invested assets	965,094	781,124
Gain (Loss) on Derivatives [Member]
Other Investments [Abstract]
Other invested assets	180,699	137,613
Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Other Investments [Abstract]
Other invested assets	197,770	218,541
Other [Member]
Other Investments [Abstract]
Other invested assets	95,829	148,114
Equity Release Mortgages [Member]
Other Investments [Abstract]
Other invested assets	$ 475,905	$ 219,940

Investments Investments (Narrat

Investments Investments (Narrative) (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2018USD ($)position	Dec. 31, 2017USD ($)position	Dec. 31, 2016USD ($)
Investment Narrative [Line Items]
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash		$ 28,600	$ 31,200
Net Amount Assets Liabilities From Repurchase Reverse Repurchase Agreements		400	1,100
Available-for-sale Securities, Amortized Cost Basis		24,006,407	21,966,803
Available-for-sale Securities		$ 23,982,119	$ 23,210,968
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | position		3,109	1,116
Proceeds From Sale Of Available For Sale Securities Sold At Loss		$ 5,784,600	$ 2,550,100	$ 1,055,500
Available-for-sale Securities, Realized Losses, Excluding Other than Temporary Impairments		158,870	37,328	47,094
ProceedsFromSaleOfAvailableForSaleEquitySecuritiesSoldAtLoss		32,800	177,700	126,100
Securities for Reverse Repurchase Agreements		$ 554,806	$ 413,819
Mortgage Loan Percent Of Invested Assets		9.10%	8.50%
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		$ 0	$ 19,156
Policy Loans Percent Of Invested Assets		2.50%	2.60%
Funds Withheld At Interest Percent Of Invested Assets		10.60%	11.80%
Percentage Of Total Gross Unrealized Losses		100.00%	100.00%
Funds withheld at interest		$ 5,761,471	$ 6,083,388
Funds Held Under Reinsurance Agreements Asset Specific Client		$ 3,800,000
Other Invested Assets Percent Of Invested Assets		3.50%	2.90%
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total		100.00%	100.00%
Collateral Obtained Percent Of Fair Value Reverse Repurchase Agreements		100.00%
Available-for-sale Equity Securities, Gross Unrealized Loss		$ 1,937	$ 4,351	$ 2,871
Non-Income Producing Securities [Member]
Investment Narrative [Line Items]
Available-for-sale Securities, Amortized Cost Basis		41,300	38,800
Available-for-sale Securities		42,700	39,300
Canadian Province Of Quebec Securities [Member]
Investment Narrative [Line Items]
Available-for-sale Securities, Amortized Cost Basis		913,642	939,837
Available-for-sale Securities		1,187,526	1,282,944
Collateral Received Fixed Maturity Securities [Member]
Investment Narrative [Line Items]
Available-for-sale Securities		616,584	590,417
Reported Value Measurement [Member]
Investment Narrative [Line Items]
Securities Borrowed		335,781	358,875
Funds withheld at interest	[1]	$ 5,655,055	$ 5,955,092
CALIFORNIA
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total		18.70%
TEXAS
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total		10.90%
GEORGIA
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total		7.40%
CANADA
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total		2.70%
UNITED KINGDOM
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total		0.10%
[1]	Carrying values presented herein may differ from those in the Company’s consolidated balance sheets because certain items within the respective financial statement captions may be measured at fair value on a recurring basis.

Derivative Instruments (Gross N

Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount of Derivatives	$ 19,884,691	$ 15,904,127
Derivative Asset, Fair Value, Gross Asset	356,666	320,724
Derivative Liability, Fair Value, Gross Liability	990,895	1,058,727
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount of Derivatives	18,044,033	14,243,031
Derivative Asset, Fair Value, Gross Asset	254,381	254,252
Derivative Liability, Fair Value, Gross Liability	963,638	1,022,122
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,040,588	996,204
Derivative Asset, Fair Value, Gross Asset	47,652	59,809
Derivative Liability, Fair Value, Gross Liability	961	2,372
Not Designated as Hedging Instrument [Member] | Future [Member]
Derivative [Line Items]
Notional Amount of Derivatives	325,620	412,438
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional Amount of Derivatives	25,000	6,030
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	234	28
Not Designated as Hedging Instrument [Member] | Consumer Price Index Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	385,580	221,932
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	11,384	2,160
Not Designated as Hedging Instrument [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,338,300	961,200
Derivative Asset, Fair Value, Gross Asset	6,003	8,319
Derivative Liability, Fair Value, Gross Liability	1,166	1,651
Not Designated as Hedging Instrument [Member] | Equity [Member]
Derivative [Line Items]
Notional Amount of Derivatives	439,158	632,251
Derivative Asset, Fair Value, Gross Asset	42,836	23,271
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument [Member] | Longevity Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	917,360	960,400
Derivative Asset, Fair Value, Gross Asset	47,789	40,659
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument [Member] | Mortality Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	25,000	0
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	369	1,683
Not Designated as Hedging Instrument [Member] | Synthetic Guaranteed Investment Contracts [Member]
Derivative [Line Items]
Notional Amount of Derivatives	13,397,729	10,052,576
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Modified Coinsurance Or Funds Withheld Arrangements [Member]
Derivative [Line Items]
Notional Amount of Derivatives	0	0
Derivative Asset, Fair Value, Gross Asset	109,597	122,194
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Indexed Annuity [Member]
Derivative [Line Items]
Notional Amount of Derivatives	0	0
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	776,940	861,758
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Variable Annuity [Member]
Derivative [Line Items]
Notional Amount of Derivatives	0	0
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	167,925	152,470
Not Designated as Hedging Instrument [Member] | Currency Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	149,698	0
Derivative Asset, Fair Value, Gross Asset	504	0
Derivative Liability, Fair Value, Gross Liability	4,659	0
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount of Derivatives	1,840,658	1,661,096
Derivative Asset, Fair Value, Gross Asset	102,285	66,472
Derivative Liability, Fair Value, Gross Liability	27,257	36,605
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	435,000	435,000
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	27,257	20,389
Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional Amount of Derivatives	911,197	553,175
Derivative Asset, Fair Value, Gross Asset	50,974	1,265
Derivative Liability, Fair Value, Gross Liability	0	7,720
Designated as Hedging Instrument [Member] | Currency Swap [Member]
Derivative [Line Items]
Notional Amount of Derivatives	494,461	672,921
Derivative Asset, Fair Value, Gross Asset	51,311	65,207
Derivative Liability, Fair Value, Gross Liability	$ 0	$ 8,496

Derivative Instruments Derivati

Derivative Instruments Derivative Instruments (Fair Value Hedge Attributable to Foreign Currency) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	[1]	$ (11,164)	$ 9,456	$ (1,700)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	[1]	$ 12,446	$ (9,456)	$ 1,700
[1]	The net amount represents the ineffective portion of the fair value hedges.

Derivative Instruments (Current

Derivative Instruments (Current Period Cash Flow Hedges in AOCI (loss) before Taxes) (Details) - Cash Flow Hedging [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Balance, Beginning of Period	$ 2,619	$ (2,496)	$ (29,397)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	6,644	6,316	27,110
Balance, End of Period	8,788	2,619	(2,496)
Gain (Loss) on Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	(775)	278
Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(292)	(505)	(487)
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (183)	$ 79	$ 0

Derivative Instruments (Cash Fl

Derivative Instruments (Cash Flow Hedges) (Details) - Cash Flow Hedging [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	$ 6,644	$ 6,316	$ 27,110
Gain (Loss) on Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	775	(278)
Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	292	505	487
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	183	(79)	0
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	12,886	(5,649)	27,901
Interest Rate Swap [Member] | Gain (Loss) on Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	0
Interest Rate Swap [Member] | Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	0
Interest Rate Swap [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	183	(79)	0
Currency Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(6,242)	11,955	(791)
Currency Swap [Member] | Gain (Loss) on Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	0
Currency Swap [Member] | Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	292	380	510
Currency Swap [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0	0	0
Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax		10	0
Forward Contracts [Member] | Gain (Loss) on Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		775	(278)
Forward Contracts [Member] | Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		125	(23)
Forward Contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		$ 0	$ 0

Derivative Instruments (Hedges

Derivative Instruments (Hedges of Net Investments in Foreign Operations) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives	[1],[2]	$ 31,431	$ (37,567)	$ (10,234)
Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives	[1],[2]	$ 55,913	$ (10,386)	$ 0
[1]	There was no ineffectiveness recognized for the Company’s hedges of net investments in foreign operations.
[2]	There were no sales or substantial liquidations of net investments in foreign operations that would have required the reclassification of gains or losses from accumulated other comprehensive income (loss) into investment income during the periods presented.

Derivative Instruments (Non Hed

Derivative Instruments (Non Hedging Derivatives and Embedded Derivatives Effect on Income Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	$ (170,088)	$ 167,880	$ 94,195
Other revenues	(363,451)	(352,108)	(266,559)
Gain Loss On Investments Related To Change In Fair Value Of Derivatives Excluding Embedded Derivatives	(96)	(42,767)	(28,611)
Interest credited	(425,204)	(502,040)	(364,691)
Not Designated as Hedging Instrument [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(557)	54,060	44,101
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(21,314)	11,278	7,649
Not Designated as Hedging Instrument [Member] | Future [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	21,200	(36,160)	(40,242)
Not Designated as Hedging Instrument [Member] | Currency Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(3,695)	0	0
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(234)	591	1,630
Not Designated as Hedging Instrument [Member] | Consumer Price Index Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(10,047)	(2,078)	(401)
Not Designated as Hedging Instrument [Member] | Credit Default Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(2,150)	18,118	18,100
Not Designated as Hedging Instrument [Member] | Equity [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	7,315	(42,953)	(28,270)
Not Designated as Hedging Instrument [Member] | Longevity Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Other revenues	(9,215)	(9,358)	(13,095)
Not Designated as Hedging Instrument [Member] | Mortality Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Other revenues	(386)	(921)	(172)
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Modified Coinsurance Or Funds Withheld Arrangements [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(12,597)	144,723	54,169
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Indexed Annuity [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Interest credited	(27,591)	(80,062)	(10,708)
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Variable Annuity [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	$ (15,455)	$ 32,166	$ 7,835

Derivative Instruments (Exposur

Derivative Instruments (Exposure from Credit Derivatives by Rating of the Underlying Credits) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 4,837	$ 7,572
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,338,300	$ 951,300
Derivative Average Remaining Maturity	[1],[3]	4 years 8 months	3 years 5 months
Standard Poors AAA To A Ratings [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 1,953	$ 3,128
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 152,000	$ 162,000
Derivative Average Remaining Maturity	[1],[3]	2 years 2 months	2 years 11 months
Standard & Poor's, BBB Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 2,854	$ 4,414
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 1,171,300	$ 784,300
Derivative Average Remaining Maturity	[1],[3]	5 years 1 month	3 years 6 months
Standard & Poor's, BB+ Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 30	$ 30
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 15,000	$ 5,000
Derivative Average Remaining Maturity	[1],[3]	8 months	1 year 6 months
Single Name Credit Default Swaps [Member] | Standard Poors AAA To A Ratings [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 1,953	$ 3,128
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 152,000	$ 162,000
Derivative Average Remaining Maturity	[1],[3]	2 years 2 months	2 years 11 months
Single Name Credit Default Swaps [Member] | Standard & Poor's, BBB Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 2,930	$ 4,469
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 353,700	$ 361,700
Derivative Average Remaining Maturity	[1],[3]	2 years 2 months	2 years 11 months
Single Name Credit Default Swaps [Member] | Standard & Poor's, BB+ Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ 30	$ 30
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 15,000	$ 5,000
Derivative Average Remaining Maturity	[1],[3]	8 months	1 year 6 months
Credit Default Swaps Referencing Indices [Member] | Standard & Poor's, BBB Rating [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net	[1]	$ (76)	$ (55)
Maximum Potential Future Exposure on Credit Risk Derivatives	[1],[2]	$ 817,600	$ 422,600
Derivative Average Remaining Maturity	[1],[3]	6 years 5 months	4 years
[1]	The rating agency designations are based on ratings from Standard and Poor’s (“S&P”).
[2]	Assumes the value of the referenced credit obligations is zero.
[3]	The weighted average years to maturity of the credit default swaps is calculated based on weighted average notional amounts.

Derivative Instruments (Derivat

Derivative Instruments (Derivative Instruments Offsetting Balance Sheet) (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Derivative Asset [Abstract]
Derivative Fair Value Of Free Standing Derivative Asset		$ 247,069	$ 198,530
Derivative Asset, Fair Value, Gross Liability		(18,581)	(20,258)
Derivative Asset		228,488	178,272
Derivative Asset, Fair Value of Collateral	[1]	0	(862)
Derivative, Collateral, Obligation to Return Cash		(235,611)	(185,900)
Derivative Asset, Fair Value, Amount Offset Against Collateral		(7,123)	(8,490)
Derivative Liability [Abstract]
Derivative Fair Value Of Free Standing Derivative Liability		46,030	44,499
Derivative Liability, Fair Value, Gross Asset		(18,581)	(20,258)
Derivative Liability		27,449	24,241
Derivative Liability, Fair Value of Collateral	[1]	(71,376)	(58,156)
Derivative, Collateral, Right to Reclaim Cash		(24,080)	(22,221)
Derivative Liability, Fair Value, Amount Offset Against Collateral		$ (68,007)	$ (56,136)
[1]	Includes initial margin posted to a central clearing partner.

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Cumulative Foreign Currency Translation Gain Loss Recorded In Accumulated Other Comprehensive Income Loss For Net Investment In Foreign Operations Hedges	$ 201	$ 113.7
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	1.9
Investment Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 0.1

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities (Balances of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	$ 39,992,346	$ 38,150,820
Non Redeemable Preferred Stock Equity Method Investments Fair Value Disclosure		39,806
Equity Method Investments, Fair Value Disclosure	82,197	60,346
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	109,597	122,194
Cash and Cash Equivalents, Fair Value Disclosure	485,167	356,788
Fair Value Measured On Recurring Basis Short Term Investments	105,991	50,746
Investments, Fair Value Disclosure	378,469	356,154
Other Assets, Fair Value Disclosure	47,789	40,659
Assets, Fair Value Disclosure	41,201,556	39,177,513
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	944,865	1,014,228
Financial Liabilities Fair Value Disclosure	972,314	1,038,469
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,067,529	1,818,006
Non Redeemable Preferred Stock Equity Method Investments Fair Value Disclosure		39,806
Equity Method Investments, Fair Value Disclosure	48,737	60,346
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	0	0
Cash and Cash Equivalents, Fair Value Disclosure	473,509	354,071
Fair Value Measured On Recurring Basis Short Term Investments	4,989	0
Investments, Fair Value Disclosure	196,781	217,618
Other Assets, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	2,791,545	2,489,847
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	0	0
Financial Liabilities Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	35,930,086	34,098,204
Non Redeemable Preferred Stock Equity Method Investments Fair Value Disclosure		0
Equity Method Investments, Fair Value Disclosure	0	0
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	0	0
Cash and Cash Equivalents, Fair Value Disclosure	11,658	2,717
Fair Value Measured On Recurring Basis Short Term Investments	98,774	47,650
Investments, Fair Value Disclosure	181,688	138,536
Other Assets, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	36,222,206	34,287,107
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	0	0
Financial Liabilities Fair Value Disclosure	27,080	22,558
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,994,731	2,234,610
Non Redeemable Preferred Stock Equity Method Investments Fair Value Disclosure		0
Equity Method Investments, Fair Value Disclosure	33,460	0
Fair Value Measured On Recurring Basis Funds Held Under Reinsurance Agreements Asset Embedded Derivatives	109,597	122,194
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair Value Measured On Recurring Basis Short Term Investments	2,228	3,096
Investments, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	47,789	40,659
Assets, Fair Value Disclosure	2,187,805	2,400,559
Liabilities, Fair Value Disclosure [Abstract]
Fair Value Measured On Recurring Basis Guaranteed Interest Contracts Embedded Derivatives	944,865	1,014,228
Financial Liabilities Fair Value Disclosure	945,234	1,015,911
Interest Rate Swap [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	37,976	51,359
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	18,542	14,311
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	37,976	51,359
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	18,542	14,311
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Foreign Exchange Forward [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	50,740	730
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure		7,213
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure		0
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	50,740	730
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure		7,213
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure		0
Consumer Price Index Swap [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure		(221)
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	11,384	1,939
Consumer Price Index Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure		0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Consumer Price Index Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure		(221)
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	11,384	1,939
Consumer Price Index Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure		0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Credit Default Swap [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	4,466	5,908
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	371	760
Credit Default Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Credit Default Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	4,466	5,908
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	371	760
Credit Default Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Equity Option [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	36,206	16,932
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	6,630	6,339
Equity Option [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Equity Option [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	36,206	16,932
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	6,630	6,339
Equity Option [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Currency Swap [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	51,311	62,905
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	4,155	6,194
Currency Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Currency Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	51,311	62,905
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	4,155	6,194
Currency Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Fair Value Option Contractholder Directed Unit Linked Investments [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	197,770	218,541
Fair Value Option Contractholder Directed Unit Linked Investments [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	196,781	217,618
Fair Value Option Contractholder Directed Unit Linked Investments [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	989	923
Fair Value Option Contractholder Directed Unit Linked Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Investments, Fair Value Disclosure	0	0
Mortality Swap [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	369	1,683
Mortality Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Mortality Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	0	0
Mortality Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Other Liabilities, Fair Value Disclosure	369	1,683
Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	23,982,119	23,210,968
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	22,651,194	21,873,696
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,330,925	1,337,272
Canadian Provincial Governments [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	3,892,385	4,220,076
Canadian Provincial Governments [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
Canadian Provincial Governments [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	3,364,261	3,626,134
Canadian Provincial Governments [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	528,124	593,942
Residential Mortgage Backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,869,221	1,719,880
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,862,366	1,611,998
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	6,855	107,882
Asset-backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,149,204	1,648,362
Assets, Fair Value Disclosure	77,842	0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,053,632	1,524,888
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	95,572	123,474
Commercial Mortgage Backed Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,419,034	1,303,387
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	1,419,012	1,300,153
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	22	3,234
US Treasury and Government [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,185,874	1,943,592
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	2,067,529	1,818,006
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	100,320	103,075
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	18,025	22,511
US States and Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	752,194	703,428
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	741,992	662,225
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	10,202	41,203
Debt Security, Government, Non-US [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	3,742,315	3,401,127
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	0	0
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	3,737,309	3,396,035
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Fixed maturity securities available-for-sale	$ 5,006	$ 5,092

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities (Fair Value Assets Transfers between Level 1 and Level 2) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$ 596,809
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	88,674
Foreign Government Debt [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	317,640
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	$ 0

Fair Value of Assets and Liab_5

Fair Value of Assets and Liabilities (Quantitative Information for Level 3 Inputs) (Details) $ in Thousands	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 41,201,556	$ 39,177,513
Longevity Swap [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	47,789	40,659
Embedded Derivatives In Indexed Annuity [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Financial and Nonfinancial Liabilities, Fair Value Disclosure	776,940	861,758
Embedded Derivatives In Variable Annuity [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Financial and Nonfinancial Liabilities, Fair Value Disclosure	167,925	152,470
Mortality Swap [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Financial and Nonfinancial Liabilities, Fair Value Disclosure	369	1,683
Foreign Government Debt [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 5,006	$ 0
Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.02	0.02
Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.04	0.04
Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.02	0.02
Debt Security, Corporate, Non-US [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0
Debt Security, Corporate, Non-US [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0
Debt Security, Corporate, Non-US [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0
US States and Political Subdivisions Debt Securities [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 0	$ 4,616
US States and Political Subdivisions Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0.01
US States and Political Subdivisions Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0.01
US States and Political Subdivisions Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0.01
Asset-backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 77,842	$ 0
Asset-backed Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0
Asset-backed Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0
Asset-backed Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0
Corporate Debt Securities [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 642,647	$ 173,579
Corporate Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0
Corporate Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.05	0.02
Corporate Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0.01
Total Return Swap [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 109,597	$ 122,194
US Government Agencies Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 18,025	$ 22,511
US Government Agencies Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0
US Government Agencies Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0.01
US Government Agencies Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0.01
Equity Securities [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 25,007	$ 0
Equity Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input	0.04	0
Equity Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input	0.04	0
Equity Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input	0.04	0
Measurement Input, Long-term Revenue Growth Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Long-term Revenue Growth Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.27	0.27
Measurement Input, Long-term Revenue Growth Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.13	0.08
Measurement Input Mortality Improvement [Member] | Longevity Swap [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	(0.10)	(0.10)
Measurement Input Mortality Improvement [Member] | Longevity Swap [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.10	0.10
Measurement Input Mortality Improvement [Member] | Longevity Swap [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.03	0.03
Measurement Input Crediting Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.02	0.02
Measurement Input Crediting Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.04	0.04
Measurement Input Crediting Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.02	0.02
Measurement Input, Counterparty Credit Risk [Member] | Embedded Derivatives In Variable Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Counterparty Credit Risk [Member] | Embedded Derivatives In Variable Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.05	0.05
Measurement Input, Counterparty Credit Risk [Member] | Embedded Derivatives In Variable Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.01	0.01
Measurement Input, Counterparty Credit Risk [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0	0
Measurement Input, Counterparty Credit Risk [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.05	0.05
Measurement Input, Counterparty Credit Risk [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.01	0.01
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.07	0.07
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.05	0.03
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.05	0.05
Measurement Input, Withdrawal Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.03	0.03
Measurement Input, Withdrawal Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0	0
Measurement Input, Withdrawal Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.05	0.05
Measurement Input, Withdrawal Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.03	0.03
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.25	0.25
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.05	0.05
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.35	0.35
Measurement Input, Lapse Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.10	0.09
Measurement Input, Lapse Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0	0
Measurement Input, Lapse Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.35	0.35
Measurement Input, Lapse Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.10	0.09
Measurement Input, Mortality Rate [Member] | Mortality Swap [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0
Measurement Input, Mortality Rate [Member] | Mortality Swap [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	1	1
Measurement Input, Mortality Rate [Member] | Mortality Swap [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.01	0.01
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	1	1
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Variable Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.01	0.01
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0	0
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	1	1
Measurement Input, Mortality Rate [Member] | Embedded Derivatives In Indexed Annuity [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Liability, Measurement Input	0.02	0.02
Measurement Input, Mortality Rate [Member] | Longevity Swap [Member] | Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0	0
Measurement Input, Mortality Rate [Member] | Longevity Swap [Member] | Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	1	1
Measurement Input, Mortality Rate [Member] | Longevity Swap [Member] | Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	0.02	0.02
Measurement Input, Mortality Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Minimum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0	0
Measurement Input, Mortality Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Maximum [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	1	1
Measurement Input, Mortality Rate [Member] | Funds Withheld At Interest Embedded Derivatives [Member] | Weighted Average [Member] | Valuation, Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Embedded Derivative Asset, Measurement Input	0.02	0.02
Measurement Input, EBITDA Multiple [Member] | Corporate Debt Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	5.9	0
Measurement Input, EBITDA Multiple [Member] | Corporate Debt Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	7.5	0
Measurement Input, EBITDA Multiple [Member] | Corporate Debt Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Instrument, Measurement Input	6.9	0
Measurement Input, EBITDA Multiple [Member] | Equity Securities [Member] | Minimum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input	6.9	0
Measurement Input, EBITDA Multiple [Member] | Equity Securities [Member] | Maximum [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input	12.3	0
Measurement Input, EBITDA Multiple [Member] | Equity Securities [Member] | Weighted Average [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input	7.9	0

Fair Value of Assets and Liab_6

Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	13,962,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(6,759,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(48,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		38,905,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0
Fair Value, Asset Value, End of period		33,460,000		$ 0
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		1,337,272,000		1,272,253,000	$ 1,226,970,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(32,983,000)		(6,719,000)	10,022,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	509,134,000		408,995,000	312,720,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(106,005,000)		(89,248,000)	(60,399,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(273,898,000)		(285,958,000)	(195,016,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		9,948,000		47,360,000	14,098,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		106,847,000		12,973,000	28,987,000
Fair Value, Asset Value, End of period		1,330,925,000		1,337,272,000	1,272,253,000
Canadian Provincial Governments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		593,942,000		475,965,000	416,076,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(79,783,000)		104,797,000	47,692,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		0	0
Fair Value, Asset Value, End of period		528,124,000		593,942,000	475,965,000
Residential Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		107,882,000		160,291,000	330,649,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(1,786,000)		2,341,000	(1,621,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	52,279,000		76,792,000	103,553,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(4,961,000)		(28,043,000)	(167,684,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(4,633,000)		(18,988,000)	(38,495,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		3,031,000		9,100,000	1,728,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		145,140,000		93,994,000	65,091,000
Fair Value, Asset Value, End of period		6,855,000		107,882,000	160,291,000
Asset-backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		123,474,000		219,280,000	303,836,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(1,344,000)		7,044,000	(2,696,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	42,120,000		45,215,000	138,522,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(462,000)		0	(38,681,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(57,476,000)		(87,328,000)	(61,770,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		73,289,000		85,152,000	56,105,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		86,163,000		147,910,000	177,938,000
Fair Value, Asset Value, End of period		95,572,000		123,474,000	219,280,000
US Treasury and Government [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		22,511,000		24,488,000	26,265,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(436,000)		19,000	39,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		418,000	[1]	465,000	508,000	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(3,837,000)	[1]	(2,000,000)	(1,837,000)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		0	0
Fair Value, Asset Value, End of period		18,025,000		22,511,000	24,488,000
US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		41,203,000		41,666,000	38,342,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		66,000		(15,000)	962,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0	[1]	0	6,952,000	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(494,000)	[1]	(843,000)	(599,000)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		9,859,000		7,294,000	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(40,441,000)		6,844,000	4,206,000
Fair Value, Asset Value, End of period		10,202,000		41,203,000	41,666,000
Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		5,092,000		12,869,000	14,065,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(86,000)		(252,000)	110,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0	[1]	496,000	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		0	[1]	(672,000)	(1,306,000)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		7,348,000	0
Fair Value, Asset Value, End of period		5,006,000		5,092,000	12,869,000
Commercial Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		3,234,000		21,145,000	68,563,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(65,000)		(71,000)	(5,887,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0	[1]	0	1,545,000	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		(1,751,000)	[1]	(3,720,000)	(41,143,000)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(5,000)	[1]	(5,404,000)	(552,000)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		1,752,000		1,302,000	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(3,144,000)		10,132,000	2,182,000
Fair Value, Asset Value, End of period		22,000		3,234,000	21,145,000
Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		122,194,000		(22,529,000)	(76,698,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		0
Fair Value, Asset Value, End of period		109,597,000		122,194,000	(22,529,000)
Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		40,659,000		26,958,000	14,996,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(2,085,000)		4,343,000	(1,133,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		0
Fair Value, Asset Value, End of period		47,789,000		40,659,000	26,958,000
Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		3,096,000		3,346,000	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		1,000		11,000	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	2,624,000		3,703,000	3,365,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(250,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(461,000)		(335,000)	(19,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(2,782,000)		3,629,000
Fair Value, Asset Value, End of period		2,228,000		3,096,000	3,346,000
Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	[1]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		0
Fair Value, Liability Value, Beginning of period		(1,014,228,000)		(990,308,000)	(1,070,584,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	[1]	(19,182,000)		(55,237,000)	(12,725,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	[1]	76,410,000		79,213,000	74,458,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3		0		0
Fair Value, Liability Value, End of period		(944,865,000)		(1,014,228,000)	(990,308,000)
Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	[1]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		0
Fair Value, Liability Value, Beginning of period		1,683,000		(2,462,000)	(2,619,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	[1]	0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	[1]	1,700,000		1,700,000	329,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3		0		0
Fair Value, Liability Value, End of period		369,000		1,683,000	(2,462,000)
Investment Income [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(1,045,000)		(1,429,000)	(2,399,000)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(998,000)		(1,457,000)	(2,343,000)
Investment Income [Member] | Canadian Provincial Governments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		13,965,000		13,180,000	12,197,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		13,965,000		13,180,000	12,197,000
Investment Income [Member] | Residential Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(129,000)		(346,000)	(595,000)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		3,000		(196,000)	(158,000)
Investment Income [Member] | Asset-backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		224,000		1,776,000	801,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		209,000		669,000	734,000
Investment Income [Member] | US Treasury and Government [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(423,000)		(461,000)	(487,000)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(417,000)		(461,000)	(487,000)
Investment Income [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		9,000		(55,000)	215,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		8,000		(54,000)	215,000
Investment Income [Member] | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		(1,000)	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		(1,000)	0
Investment Income [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		709,000	1,677,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	1,552,000
Investment Related Gains Losses [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(12,600,000)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(15,992,000)
Investment Related Gains Losses [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(4,651,000)		4,991,000	(4,756,000)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(6,320,000)		(5,389,000)	(817,000)
Investment Related Gains Losses [Member] | Canadian Provincial Governments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | Residential Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		312,000		729,000	(2,153,000)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		(346,000)	(231,000)
Investment Related Gains Losses [Member] | Asset-backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		1,910,000		245,000	1,101,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | US Treasury and Government [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(208,000)		0	0
Investment Related Gains Losses [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Investment Related Gains Losses [Member] | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Investment Related Gains Losses [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		1,000		(595,000)	(876,000)
Investment Related Gains Losses [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(12,597,000)		144,723,000	54,169,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(12,597,000)		144,723,000	54,169,000
Investment Related Gains Losses [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		15,455,000		(32,166,000)	(7,834,000)
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(22,393,000)		23,472,000	(4,579,000)
Investment Related Gains Losses [Member] | Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0
Interest Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(27,590,000)		80,062,000	(10,709,000)
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(48,819,000)		(159,276,000)	(63,748,000)
Interest Income [Member] | Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Other Income [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0
Other Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Other Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		9,215,000		9,358,000	13,095,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		9,215,000		9,358,000	13,095,000
Other Income [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Other Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Other Income [Member] | Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(386,000)		921,000	172,000
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ (386,000)		$ (921,000)	$ (172,000)
[1]	The amount reported within purchases, sales and settlements is the purchase price (for purchases) and the sales/settlement proceeds (for sales and settlements) based upon the actual date purchased or sold/settled. Items purchased and sold/settled in the same period are excluded from the rollforward. The Company had no issuances during the period.

Fair Value of Assets and Liab_7

Fair Value of Assets and Liabilities (Fair Value Assets Measured on Non-Recurring Basis) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Private Equity Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value Assets Carrying Value Prior To Impairment	[1]	$ 0	$ 106
Fair Value Assets Gains Losses	[1]	0	(531)
Partnership Interest [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value Assets Carrying Value Prior To Impairment	[2]	4,596	4,656
Fair Value Assets Gains Losses	[2]	$ (3,200)	$ (7,204)
[1]	The fair value of the Company’s private equity investments is based on external valuation models.
[2]	The impaired limited partnership interests presented above were accounted for using the cost method. Impairments on these cost method investments were recognized at estimated fair value determined using the net asset values of the Company’s ownership interest as provided in the financial statements of the investees. The market for these investments has limited activity and price transparency

Fair Value of Assets and Liab_8

Fair Value of Assets and Liabilities (Financial Instruments where Carrying Amounts and Fair Values May Differ) (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate		$ 4,966,298	$ 4,400,533
Policy loans		1,344,980	1,357,624
Funds withheld at interest		5,761,471	6,083,388
Cash and cash equivalents		1,889,733	1,303,524	$ 1,200,718	$ 1,525,275
Short-term investments		142,598	93,304
Other invested assets		1,915,297	1,505,332
Accrued investment income		427,893	392,721
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities		18,004,526	16,227,642
Collateral finance and securitization notes		681,961	783,938
Carrying Value [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate	[1]	4,966,298	4,400,533
Policy loans	[1]	1,344,980	1,357,624
Funds withheld at interest	[1]	5,655,055	5,955,092
Cash and cash equivalents	[1]	1,404,566	946,736
Short-term investments	[1]	36,607	42,558
Other invested assets	[1]	945,731	690,198
Accrued investment income	[1]	427,893	392,721
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities	[1]	14,547,436	12,683,872
Long And Short Term Debt	[1]	2,787,873	2,788,365
Collateral finance and securitization notes	[1]	681,961	783,938
Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate		4,917,416	4,477,654
Policy loans		1,344,980	1,357,624
Funds withheld at interest		5,802,518	6,275,623
Cash and cash equivalents		1,404,566	946,736
Short-term investments		36,607	42,558
Other invested assets		941,449	718,282
Accrued investment income		427,893	392,721
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities		14,611,011	12,917,243
Long And Short Term Debt		2,752,047	2,959,912
Collateral finance and securitization notes		626,731	722,145
Estimate of Fair Value Measurement [Member] | Net Asset Value [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate		0	0
Policy loans		0	0
Funds withheld at interest		0	0
Cash and cash equivalents		0	0
Short-term investments		0	0
Other invested assets		376,392	335,125
Accrued investment income		0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities		0	0
Long And Short Term Debt		0	0
Collateral finance and securitization notes		0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate		0	0
Policy loans		0	0
Funds withheld at interest		0	0
Cash and cash equivalents		1,404,566	946,736
Short-term investments		36,607	42,558
Other invested assets		4,640	28,540
Accrued investment income		0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities		0	0
Long And Short Term Debt		0	0
Collateral finance and securitization notes		0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate		0	0
Policy loans		1,344,980	1,357,624
Funds withheld at interest		0	0
Cash and cash equivalents		0	0
Short-term investments		0	0
Other invested assets		83,203	67,778
Accrued investment income		427,893	392,721
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities		0	0
Long And Short Term Debt		0	0
Collateral finance and securitization notes		0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans on real estate		4,917,416	4,477,654
Policy loans		0	0
Funds withheld at interest		5,802,518	6,275,623
Cash and cash equivalents		0	0
Short-term investments		0	0
Other invested assets		477,214	286,839
Accrued investment income		0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Interest-sensitive contract liabilities		14,611,011	12,917,243
Long And Short Term Debt		2,752,047	2,959,912
Collateral finance and securitization notes		$ 626,731	$ 722,145
[1]	Carrying values presented herein may differ from those in the Company’s consolidated balance sheets because certain items within the respective financial statement captions may be measured at fair value on a recurring basis.

Fair Value of Assets and Liab_9

Fair Value of Assets and Liabilities (Narrative) (Details)	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Percentage Of Fixed Maturity Securities Classified As Level 3	5.00%	5.90%

Reinsurance Reinsurance (Ceded

Reinsurance Reinsurance (Ceded Reinsurance Receivable Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 757,572	$ 782,027
Reinsurance Recoverables, Percentage of Total	100.00%	100.00%
Other Reinsurers [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 114,723	$ 127,808
Reinsurance Recoverables, Percentage of Total	15.20%	16.20%
AM Best, A+ Rating [Member] | Reinsurer A [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 303,036	$ 301,478
Reinsurance Recoverables, Percentage of Total	40.00%	38.60%
AM Best, A+ Rating [Member] | Reinsurer B [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 193,324	$ 203,898
Reinsurance Recoverables, Percentage of Total	25.50%	26.10%
AM Best, A+ Rating [Member] | Reinsurer D [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 40,004	$ 40,528
Reinsurance Recoverables, Percentage of Total	5.30%	5.20%
AM Best, A Rating [Member] | Reinsurer C [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 69,885	$ 67,723
Reinsurance Recoverables, Percentage of Total	9.20%	8.70%
AM Best, A++ Rating [Member] | Reinsurer E [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 36,600	$ 40,592
Reinsurance Recoverables, Percentage of Total	4.80%	5.20%

Reinsurance (Effect of Reinsura

Reinsurance (Effect of Reinsurance on Net Premiums and Claims and Other Policy Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Premiums Earned, Net [Abstract]
Direct Premiums Earned	$ 62,526	$ 61,571	$ 57,562
Assumed Premiums Earned	11,341,284	10,642,462	10,049,587
Ceded Premiums Earned	(860,034)	(862,903)	(858,278)
Net premiums	10,543,776	9,841,130	9,248,871
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Direct	107,405	104,447	105,435
Policyholder Benefits and Claims Incurred, Assumed	9,997,173	9,281,590	8,621,647
Policyholder Benefits and Claims Incurred, Ceded	(785,649)	(867,120)	(733,707)
Claims and other policy benefits	$ 9,318,929	$ 8,518,917	$ 7,993,375

Reinsurance (Effect of Reinsu_2

Reinsurance (Effect of Reinsurance on Life Insurance In Force) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reinsurance Disclosures [Abstract]
Reinsurance Premiums for Insurance Companies, by Product Segment, Gross Amount	$ 1,363	$ 1,462	$ 1,576
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Assumed from Other Companies	3,329,181	3,297,275	3,062,525
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	186,172	205,529	214,727
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 3,144,372	$ 3,093,208	$ 2,849,374
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	105.90%	106.60%	107.50%

Reinsurance (Narrative) (Detail

Reinsurance (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Effects of Reinsurance [Line Items]
Maximum Life Insurance Retention Per Individual Life	$ 8,000
Reinsurance ceded receivables	757,572	$ 782,027
Reinsurance Claims Recoverables	242,800	243,800
Claims Recoverable From Retrocessionaires Past Due	17,400	1,900
Statutory Financial Reinsurance	18,100,000	16,200,000
Statutory Reserves Related To Financial Requirements	3,421,000	2,901,100
Assets Held-in-trust	767,900	841,500
Benefit Of RGA Subsidiaries [Member]
Effects of Reinsurance [Line Items]
Assets Held-in-trust	2,910,200	2,214,100
Benefit Of Third Parties [Member]
Effects of Reinsurance [Line Items]
Assets Held-in-trust	$ 20,072,700	$ 15,584,300
AM Best, A- Rating [Member]
Effects of Reinsurance [Line Items]
Retrocession Pool Participants Minimum AM Best Rating	“A- (excellent)”	“A- (excellent)”
AM Best, B+ Rating [Member]
Effects of Reinsurance [Line Items]
Retrocession Pool Participants Minimum AM Best Rating	B+

Deferred Policy Acquisition C_3

Deferred Policy Acquisition Costs (Movement Analysis Of Deferred Policy Acquisition Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred Policy Acquisition Costs	$ 3,239,824	$ 3,338,605	$ 3,392,437
Deferred Policy Acquisition Costs, Additions	607,743	348,470	350,233
Deferred Policy Acquisition Costs, Amortization Expense	(437,696)	(432,474)	(341,115)
Deferred Policy Acquisition Cost, Amortization Expense, Other	14,658	(70,392)	(40,077)
Deferred Policy Acquisition Cost, Amortization Expense, Unrealized Investment Gains (Losses)	26,608	(8,220)	(3,541)
Deferred Policy Acquisition Cost, Foreign Currency Translation Adjustment	(53,367)	63,835	(19,332)
Deferred Policy Acquisition Costs	$ 3,397,770	$ 3,239,824	$ 3,338,605

Deferred Policy Acquisition C_4

Deferred Policy Acquisition Costs Deferred Policy Acquisition Costs (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred Policy Acquisition Costs Disclosure	Some reinsurance agreements involve reimbursing the ceding company for allowances and commissions in excess of first-year premiums. These amounts represent acquisition costs and are capitalized to the extent deemed recoverable from the future premiums and amortized against future profits of the business.

Income Tax (Pre-tax Income Fore

Income Tax (Pre-tax Income Foreign and Domestic) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Domestic									$ 626,197	$ 870,532	$ 758,496
Income (Loss) from Continuing Operations before Income Taxes, Foreign									219,623	272,283	285,450
Income before income taxes	$ 137,946	$ 322,661	$ 247,288	$ 137,925	$ 255,494	$ 340,162	$ 339,315	$ 207,844	$ 845,820	$ 1,142,815	$ 1,043,946

Income Tax (Provision for Incom

Income Tax (Provision for Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 78,431	$ 131,108	$ 1,020
Current Federal Tax Expense (Benefit) Relating To US Tax Reform	(68,080)	0	0
Current Foreign Tax Expense (Benefit)	43,120	36,830	47,706
Current Income Tax Expense (Benefit)	53,471	167,938	48,726
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	62,890	159,853	273,928
Deferred Federal Income Tax Expense (Benefit) Related To US Tax Reform	5,907	(1,033,755)	0
Tax Adjustments, Settlements, and Unusual Provisions	(62,173)	(1,033,755)	0
Deferred Foreign Income Tax Expense (Benefit)	7,710	26,598	19,849
Deferred income taxes	76,507	(847,304)	293,777
Income Tax Expense (Benefit)	$ 129,978	$ (679,366)	$ 342,503

Income Tax (Provision for Inc_2

Income Tax (Provision for Income Tax Expense Computed from Statutory Rate to Pre-tax Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation, Equity in Earnings (Losses) of Unconsolidated Subsidiary, Amount	$ (6,103)	$ (10,532)	$ 0
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	177,622	399,985	365,381
Tax Adjustments, Settlements, and Unusual Provisions	(62,173)	(1,033,755)	0
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	4,526	(21,867)	(13,974)
Income Tax Reconciliation Foreign Income Tax Basis Differential	(23,257)	(23,324)	(17,770)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	23,144	29,458	10,963
Effective Income Tax Rate Reconciliation, Tax Contingency, Domestic, Amount	1,516	(7,184)	111
Income Tax Reconciliation Change In Foreign Enacted Tax Rate	1,008	(6,065)	0
Gilti Net of Credits	10,400	0	0
Income Tax Reconciliation Subpart F	583	1,528	1,783
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount	(2,544)	(1,681)	(1,683)
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount	(1,305)	(4,674)	(1,473)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	6,561	(1,255)	(835)
Income Tax Expense (Benefit)	$ 129,978	$ (679,366)	$ 342,503
Effective Income Tax Rate Reconciliation, Percent	15.40%	(59.40%)	32.80%

Income Tax (Total Income Taxes

Income Tax (Total Income Taxes Provided) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Effects Allocated Directly to Equity [Abstract]
Income Tax Expense (Benefit)	$ 129,978	$ (679,366)	$ 342,503
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	(367,933)	306,849	157,929
Income Tax Effects Allocated Directly to Equity, Employee Stock Options	0	0	(162)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	19,101	(42,153)	21,081
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	134	404	1,772
Income Tax Expense (Benefit), Intraperiod Tax Allocation	$ (218,720)	$ (414,266)	$ 523,123

Income Tax (Tax Effects of Temp

Income Tax (Tax Effects of Temporary Differences that Give Rise to Significant Portions of the Deferred Income Tax Asset and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets, Net [Abstract]
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals	$ 86,092	$ 80,905
Deferred Tax Assets Reinsurance Transactions	102,014	96,043
Deferred Tax Assets Cash And Invested Assets	28,398	557
Deferred Tax Assets Investment Income	80,200	43,230
Deferred Tax Assets Deferred Acquisition Costs Capitalized For Tax	124,707	88,531
Deferred Tax Assets, Operating Loss Carryforwards	405,958	535,374
Deferred Tax Assets Deferred Acquisition Costs Capitalized For Financial Reporting	32,897	102,143
Deferred Tax Assets, Gross	860,266	946,783
Deferred Tax Assets, Valuation Allowance	(181,110)	(226,884)
Deferred Tax Assets, Net	679,156	719,899
Deferred Tax Liabilities [Abstract]
Deferred Tax Liabilities, Deferred Expense, Deferred Policy Acquisition Cost	843,328	627,378
Deferred Tax Liabilities Reinsurance Transactions	1,151,419	1,547,101
Deferred Tax Liabilities Cash And Invested Assets	345,836	674,569
Deferred Tax Liabilities Investment Income	9,493	1,858
Deferred Tax Liabilities, Unrealized Currency Transaction Gains	52,928	33,803
Deferred Tax Liabilities, Prepaid Expenses	25,433	0
Total Deferred Income Tax Liabilities	2,428,437	2,884,709
Deferred Tax Liabilities, Net	1,749,281	2,164,810
Balance Sheet Presentation Of Deferred Tax Liabilities [Abstract]
Deferred Tax Assets, Other	49,519	33,499
Deferred income taxes	1,798,800	2,198,309
Deferred Tax Liabilities, Net	$ 1,749,281	$ 2,164,810

Income Tax Income Tax (Net Oper

Income Tax Income Tax (Net Operating Loss Carryforward) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 1,733
No Expiration And No Valuation Allowance [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	52
Full Valuation Allowance [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	167
No Expiration And Partial Valuation Allowance [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	396
Expiration Dates Between 2029 And 2035 With No Valuation Allowance [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 1,118

Income Tax (Reconciliation of t

Income Tax (Reconciliation of the Amount of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Increase Resulting from Acquisition	$ 521	$ 0	$ 0
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits Beginning balance, January 1	321,224	297,290	296,213
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	255,970	247,596	226,720
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions	(256,587)	(246,894)	(229,719)
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	3,682	36,438	4,186
Unrecognized Tax Benefits, Payment On Deposit	(185)	0	0
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	0	(13,206)	(110)
Unrecognized Tax Benefits Ending balance, December 31	$ 324,625	$ 321,224	$ 297,290

Income Tax (Narrative) (Details

Income Tax (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 27,800	$ 152,000
Valuation Allowance Related To Tax Cuts And Jobs Act Of 2017	58,900
Foreign Currency Translation Adjustment On Valuation Allowance	(12,800)	10,600
Reclassification With Other Deferred Tax Assets Impact on Valuation Allowance		(5,600)
Cash paid for income taxes	144,100	48,700	$ 68,000
Tax Adjustments, Settlements, and Unusual Provisions	(62,173)	(1,033,755)	0
Deferred Tax Assets, Valuation Allowance	181,110	226,884
Proceeds from Income Tax Refunds	2,400	11,600	6,900
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability	1,364,100	1,442,900
Tax Credit Carryforward, Valuation Allowance	65,100
Subsidiary Net Operating Loss	24,500
Operating Loss Carryforwards	1,733
Unrecognized Tax Benefits	324,625	321,224	297,290	$ 296,213
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	12,800
Unrecognized Tax Benefits, Interest on Income Taxes Expense	3,300	5,000	$ 8,400
Income Tax Examination, Penalties Expense		300
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 11,600	15,100
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign		3,300
Foreign Tax Authority [Member] | Australian Taxation Office [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign		20,100
Foreign Tax Authority [Member] | Revenue Commissioners, Ireland [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign		$ 65,100

Employee Benefit Plans (Schedul

Employee Benefit Plans (Schedule of Changes in Projected Benefit Obligations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	$ 172,143
Defined Benefit Plan, Benefit Obligation, Ending Balance	178,604	$ 172,143
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	172,143	161,955
Defined Benefit Plan, Service Cost	12,502	10,686	$ 10,319
Defined Benefit Plan, Interest Cost	5,405	5,326	4,790
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	159	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	(1,045)	11,336
Defined Benefit Plan Settlement Gain Loss	0	(438)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	12,907
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(7,801)	(5,974)
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	(2,600)	2,000
Defined Benefit Plan, Benefit Obligation, Ending Balance	178,604	172,143	161,955
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	70,198	60,524
Defined Benefit Plan, Service Cost	3,028	2,543	2,883
Defined Benefit Plan, Interest Cost	2,319	2,118	2,259
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	432	354
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0	(13,743)
Defined Benefit Plan, Actuarial Net (Gains) Losses	(7,172)	5,510
Defined Benefit Plan Settlement Gain Loss	0	0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(1,409)	(851)
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	0	0
Defined Benefit Plan, Benefit Obligation, Ending Balance	$ 67,396	$ 70,198	$ 60,524

Employee Benefit Plans (Sched_2

Employee Benefit Plans (Schedule of Changes in Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	$ 103,236
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	102,561	$ 103,236
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(76,043)	(68,907)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	103,236	84,770
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	(6,464)	14,481
Defined Benefit Plan, Plan Assets, Contributions by Employer	13,590	22,866
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Plan Assets, Payment for Settlement	0	(12,907)
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(7,801)	(5,974)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	102,561	103,236
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(76,043)	(68,907)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	977	497
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	432	354
Defined Benefit Plan, Plan Assets, Payment for Settlement	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(1,409)	(851)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (67,396)	$ (70,198)

Employee Benefit Plans (Sched_3

Employee Benefit Plans (Schedule of Net Funded Status) (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 102,561	$ 103,236
Defined Benefit Plan, Benefit Obligation		178,604	172,143
Defined Benefit Plan, Funded Status of Plan, Total		(76,043)	(68,907)
Qualified Plan [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount		102,561	103,236
Defined Benefit Plan, Benefit Obligation		112,093	107,072
Defined Benefit Plan, Funded Status of Plan, Total		(9,532)	(3,836)
Nonqualified Plan [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	[1]	0	0
Defined Benefit Plan, Benefit Obligation	[1]	66,511	65,071
Defined Benefit Plan, Funded Status of Plan, Total	[1]	$ (66,511)	$ (65,071)
[1]	For non-qualified plans, there are no required funding levels.

Employee Benefit Plans (Sched_4

Employee Benefit Plans (Schedule of Amounts Recognized in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	$ 48,744	$ 40,058
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Costs (Credit) Arising During Period, Net of Tax	436	804
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	49,180	40,862
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	25,923	35,672
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Costs (Credit) Arising During Period, Net of Tax	(10,491)	(11,806)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 15,432	$ 23,866

Employee Benefit Plans (Sched_5

Employee Benefit Plans (Schedule of Projected Benefit Obligations in Excess of Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Defined Benefit Plan, Benefit Obligation	$ 178,604	$ 172,143
Defined Benefit Plan, Plan Assets, Amount	$ 102,561	$ 103,236

Employee Benefit Plans (Sched_6

Employee Benefit Plans (Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	$ 174,400	$ 169,705
Defined Benefit Plan, Plan Assets, Amount	$ 102,561	$ 103,236

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Benefit Cost Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	$ 1,063	$ (10,587)	$ 4,427
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	947	(11,717)	(444)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	12,502	10,686	10,319
Defined Benefit Plan, Interest Cost	5,405	5,326	4,790
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(7,535)	(6,215)	(5,138)
Defined Benefit Plan, Amortization of Gain (Loss)	3,728	4,382	4,323
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	344	344	294
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0	(4,785)	(1,026)
Defined Benefit Plan, Net Periodic Benefit Cost, Total	14,444	19,308	15,614
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	12,954	2,633	8,785
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(3,728)	(4,382)	(4,323)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	(344)	(344)	(294)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	0	(4,785)	(1,026)
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	159	0
Other Comprehensive Income Defined Benefit Plan Net Foreign Exchange Translations And Other Adjustments	(565)	759	707
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	8,317	(5,960)	3,849
Defined Benefit Plan Net Periodic Benefit Cost And Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Period Increase Decrease	22,761	13,348	19,463
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	3,028	2,543	2,883
Defined Benefit Plan, Interest Cost	2,319	2,118	2,259
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	0	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	2,577	1,992	1,827
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(1,315)	(1,315)	(622)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost, Total	6,609	5,338	6,347
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	(7,172)	5,507	6,228
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(2,577)	(1,992)	(1,827)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	1,315	1,315	622
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	0	0	0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0	(13,743)
Other Comprehensive Income Defined Benefit Plan Net Foreign Exchange Translations And Other Adjustments	0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	(8,434)	4,830	(8,720)
Defined Benefit Plan Net Periodic Benefit Cost And Other Comprehensive Income Defined Benefit Plans Adjustment Before Tax Period Increase Decrease	$ (1,825)	$ 10,168	$ (2,373)

Employee Benefit Plans (Sched_7

Employee Benefit Plans (Schedule of Expected Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 9,977
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	12,013
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	11,663
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	14,229
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	14,128
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	77,832
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	1,528
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	1,835
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	2,209
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	2,633
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	3,009
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 20,359

Employee Benefit Plans (Sched_8

Employee Benefit Plans (Schedule of Assumptions Used Calculating Benefit Obligations) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.02%	3.40%	3.80%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.41%	3.81%	3.95%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	7.35%	7.35%	7.35%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	4.17%	4.16%	4.08%
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.17%	3.56%	4.10%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.56%	4.10%	4.43%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	0.00%	0.00%	0.00%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	0.00%	0.00%	0.00%

Employee Benefit Plans (Sched_9

Employee Benefit Plans (Schedule of Health Care Costs Trend Rates) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Medicare Eligible Claims [Member]
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	10.00%	8.00%
Defined Benefit Plan, Assumed Health Care Cost Trend Rate, Description	8% down to 5% in 2024	9% down to 5% in 2024
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2,024	2,020
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
Pre Medicare Eligible Claims [Member]
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	10.00%	8.00%
Defined Benefit Plan, Assumed Health Care Cost Trend Rate, Description	8% down to 5% in 2024	9% down to 5% in 2024
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2,024	2,020
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%

Employee Benefit Plans (Sche_10

Employee Benefit Plans (Schedule of Allocation of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018		Dec. 31, 2017
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 102,561		$ 103,236
Mutual Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 102,414	[1]	$ 103,106	[2]
U.S. Equity Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	25.00%		27.00%
U.S. Fixed Income Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	42.00%		36.00%
Non-U.S. Equity Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	17.00%		22.00%
Other [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	16.00%		15.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 147		$ 130
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	102,561		103,236
Fair Value, Inputs, Level 1 [Member] | Mutual Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	102,414	[1]	103,106	[2]
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	147		130
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0		0
Fair Value, Inputs, Level 2 [Member] | Mutual Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	[1]	0	[2]
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0		0
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0		0
Fair Value, Inputs, Level 3 [Member] | Mutual Funds [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	[1]	0	[2]
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 0		$ 0
[1]	Mutual funds were invested 25% in U.S. equity funds, 42% in U.S. fixed income funds, 17% in non-U.S. equity funds and 16% in other.
[2]	Mutual funds were invested 27% in U.S. equity funds, 36% in U.S. fixed income funds, 22% in non-U.S. equity funds and 15% in other.

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	$ 174,400	$ 169,705
Defined Contribution Plan, Cost	15,300	14,200	$ 9,900
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	14,444	19,308	15,614
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	16,300
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	6,609	$ 5,338	$ 6,347
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 1,500
Debt Securities [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	40.00%
Equity Securities [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	60.00%

Financial Condition and Net I_3

Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries (Statutory Accounting Practices Disclosure) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
RGA Reinsurance [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 2,078,654	$ 1,584,007
Statutory Accounting Practices, Statutory Net Income Amount	659,941	138,359	$ 148,576
RCM [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	2,053,379	1,557,453
Statutory Accounting Practices, Statutory Net Income Amount	(24,907)	(183,136)	272,038
RGA Canada [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	896,760	1,006,190
Statutory Accounting Practices, Statutory Net Income Amount	(37,922)	25,971	13,947
RGA Barbados [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	1,169,790	1,278,006
Statutory Accounting Practices, Statutory Net Income Amount	48,779	309,346	95,859
RGA Australia [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	433,406	476,528
Statutory Accounting Practices, Statutory Net Income Amount	(37,208)	78,497	(7,694)
RGA Atlantic [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	1,083,181	812,307
Statutory Accounting Practices, Statutory Net Income Amount	256,080	213,511	110,172
RGA Americas [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	4,298,368	4,833,890
Statutory Accounting Practices, Statutory Net Income Amount	208,999	624,145	282,226
Other Reinsurance Subsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	2,572,307	2,694,317
Statutory Accounting Practices, Statutory Net Income Amount	$ 345,249	$ 65,658	$ 130,289

Financial Condition and Net I_4

Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries (Reconciliation of NAIC SAP and Prescribed Practice) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statutory Basis [Abstract]
Prescribed Practice Surplus Note	$ 624,266	$ 726,531
Prescribed Practice Letters Of Credit	(976,100)	(960,100)
Surplus Deficit NAIC SAP	$ (351,834)	$ (233,569)

Financial Condition and Net I_5

Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Statutory Basis [Abstract]
Number Of Preceeding Months To Accumulate Dividend Paid For Approval	12 months
Future Dividend Payment Restricted To Such Percent Of Surplus To Policy Holders	10.00%
RGA Reinsurance Max Dividend Payments Without Approval	$ 653.9

Commitments Contingencies and_3

Commitments Contingencies and Guarantees (Commitments to Fund Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Limited Partner [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 523,903	$ 485,197
Commercial Loan [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	22,605	40,815
Bank Loan Obligations [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	137,076	60,472
Equity Release Mortgages [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 264,858	$ 153,937

Commitments Contingencies and_4

Commitments Contingencies and Guarantees (Schedule of Future Minimum Rental Payments for Operating Leases) (Details) - Property Subject to Operating Lease [Member] $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases, Future Minimum Payments Due [Abstract]
Operating Leases, Future Minimum Payments Due, Current	$ 13,578
Operating Leases, Future Minimum Payments, Due in Two Years	11,541
Operating Leases, Future Minimum Payments, Due in Three Years	9,447
Operating Leases, Future Minimum Payments, Due in Four Years	8,587
Operating Leases, Future Minimum Payments, Due in Five Years	8,248
Operating Leases, Future Minimum Payments, Due Thereafter	$ 14,101

Commitments Contingencies and_5

Commitments Contingencies and Guarantees (Maximum Potential Obligation) (Details) $ in Millions	Dec. 31, 2018USD ($)
Commitment Period Two Thousand Twenty Six [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 500
Commitment Period Two Thousand Thirty Three [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	450
Commitment Period Two Thousand Thirty Four [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	2,000
Commitment Period Two Thousand Thirty Five [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	1,314.2
Commitment Period Two Thousand Thirty Six [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	2,658
Commitment Period Two Thousand Thirty Seven [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 6,750

Commitments Contingencies and_6

Commitments Contingencies and Guarantees (Guarantees Issued) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Insurance Treaty Guarantee [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Current Carrying Value	$ 1,392,352	$ 1,047,449
Insurance Treaty Guarantee Net Of Assets Held In Trust [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Current Carrying Value	1,291,445	926,393
Guarantee Of Borrowed Securities [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Current Carrying Value	269,980	294,325
Product Financing Arrangement [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Current Carrying Value	61,273	86,183
Guarantee Of Lease Obligations [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Current Carrying Value	392	$ 1,662
Commitment Period Two Thousand Thirty Seven [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	6,750
Commitment Period Two Thousand Thirty Eight [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 800

Commitments Contingencies and_7

Commitments Contingencies and Guarantees (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Rent Expense	$ 17.5	$ 15.7	$ 13.7
Maximum Capital Lease Obligations As Offset Against Industrial Bonds	$ 150

Debt (Schedule of Long-term Deb

Debt (Schedule of Long-term Debt Instruments) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2006
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 2,806,524,000	$ 2,808,770,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	18,651,000	20,405,000
Debt Instrument, Face Amount			$ 850,000,000
Long-term debt	2,787,873,000	2,788,365,000
Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 300,000,000
Debt Instrument, Maturity Date	Dec. 31, 2017
Debt Instrument, Interest Rate, Stated Percentage	5.625%
Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 399,941,000	399,873,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2019
Debt Instrument, Interest Rate, Stated Percentage	6.45%
Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 399,466,000	399,245,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2021
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 399,288,000	399,138,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2023
Debt Instrument, Interest Rate, Stated Percentage	4.70%
Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 399,988,000	399,987,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2026
Debt Instrument, Interest Rate, Stated Percentage	3.95%
Subordinated Debentures Due 2042 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000,000	400,000,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2042
Debt Instrument, Interest Rate, Stated Percentage	6.20%
Subordinated Debentures Due 2056 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000,000	400,000,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2056
Debt Instrument, Interest Rate, Stated Percentage	5.75%
Junior Subordinated Debentures Due 2065 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 318,743,000	318,740,000
Debt Instrument, Face Amount	$ 400,000,000
Debt Instrument, Maturity Date	Dec. 31, 2065
Debt Instrument, Interest Rate, Stated Percentage	4.82%
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 89,098,000	$ 91,787,000
Debt Instrument, Face Amount	$ 100,000,000
Debt Instrument, Maturity Date	Dec. 31, 2039
Debt Instrument, Interest Rate, Stated Percentage	4.09%

Debt (Repayments of Debt) (Deta

Debt (Repayments of Debt) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt Disclosure [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 402,802
Long-term Debt, Maturities, Repayments of Principal in Year Two	2,919
Long-term Debt, Maturities, Repayments of Principal in Year Three	403,040
Long-term Debt, Maturities, Repayments of Principal in Year Four	3,167
Long-term Debt, Maturities, Repayments of Principal in Year Five	403,299
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 1,593,674

Debt (Schedule of Line of Credi

Debt (Schedule of Line of Credit Facilities) (Details) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,260,300,000
Syndicated Credit Facility $850 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date		Aug. 31, 2023
Line of Credit Facility, Maximum Borrowing Capacity		$ 850,000,000
Long-term Line of Credit	[1]	$ 18,153,000	$ 95,564,000
Line of Credit Facility, Interest Rate Description		Senior unsecured long-term debt rating
Credit Facility 270 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date		Nov. 30, 2019
Credit Facility Two Thousand Nineteen [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date	[2]	Mar. 31, 2019
Line of Credit Facility, Maximum Borrowing Capacity	[2]	$ 191,583,000
Long-term Line of Credit	[1],[2]	$ 4,156,000	5,952,000
Line of Credit Facility, Interest Rate Description	[2]	Fixed
Credit Facility $188 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 188,000,000
Long-term Line of Credit	[1]	$ 188,000,000	188,000,000
Line of Credit Facility, Interest Rate Description		Fixed
Credit Facility 100 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date		Jun. 30, 2020
Line of Credit Facility, Maximum Borrowing Capacity		$ 100,000,000
Long-term Line of Credit	[1]	$ 0	75,573,000
Line of Credit Facility, Interest Rate Description		Fixed
Foreign Credit Facility December 2019 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date	[2]	Dec. 31, 2019
Line of Credit Facility, Maximum Borrowing Capacity	[2]	$ 105,735,000
Long-term Line of Credit	[1],[2]	$ 105,735,000	117,135,000
Line of Credit Facility, Interest Rate Description	[2]	Fixed
Credit Facility $100 Million 2021 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date		May 31, 2021
Line of Credit Facility, Maximum Borrowing Capacity		$ 100,000,000
Long-term Line of Credit	[1]	$ 61,000,000	100,000,000
Line of Credit Facility, Interest Rate Description		Fixed
Syndicated Credit Facility $75 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date		Jun. 30, 2021
Line of Credit Facility, Maximum Borrowing Capacity		$ 75,000,000
Long-term Line of Credit	[1]	$ 33,900,000	61,900,000
Line of Credit Facility, Interest Rate Description		Fixed
Syndicated Credit Facility $500 Million [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Date		May 31, 2022
Line of Credit Facility, Maximum Borrowing Capacity		$ 500,000,000
Long-term Line of Credit	[1]	$ 395,000,000	$ 500,000,000
Line of Credit Facility, Interest Rate Description		Debt rating and utilization %
[1]	Represents issued but undrawn letters of credit. There was no cash borrowed for the periods presented.
[2]	Foreign currency denominated facility, amounts presented are in U.S. dollars.

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2006
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net		$ 18,651,000	$ 20,405,000
Undrawn Outstanding Letters Of Credit In Favor Of Third Parties		105,600,000	120,100,000
Undrawn Outstanding Letters Of Credit Between Subsidiaries		1,356,900,000	1,492,200,000
Debt Instrument, Face Amount					$ 850,000,000
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,260,300,000
Debt, Weighted Average Interest Rate		5.24%
Long-term Debt, Gross		$ 2,806,524,000	2,808,770,000
Long-term debt		2,787,873,000	2,788,365,000
Long-term Debt, Maturities, Repayments of Principal in Year Four		3,167,000
Line of Credit Facility, Commitment Fee Amount		$ 9,700,000	10,500,000	$ 7,900,000
Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.95%
Debt Instrument, Maturity Date		Dec. 31, 2026
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 399,988,000	399,987,000
Subordinated Debentures Due 2056 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.75%
Debt Instrument, Maturity Date		Dec. 31, 2056
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 400,000,000	400,000,000
Junior Subordinated Debentures Due 2065 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.82%
Debt Instrument, Maturity Date		Dec. 31, 2065
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 318,743,000	318,740,000
Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.00%
Debt Instrument, Maturity Date		Dec. 31, 2021
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 399,466,000	399,245,000
Subordinated Debentures Due 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.20%
Debt Instrument, Maturity Date		Dec. 31, 2042
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 400,000,000	400,000,000
Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.70%
Debt Instrument, Maturity Date		Dec. 31, 2023
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 399,288,000	399,138,000
Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.09%
Debt Instrument, Maturity Date		Dec. 31, 2039
Debt Instrument, Face Amount		$ 100,000,000
Long-term Debt, Gross		$ 89,098,000	91,787,000
Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.45%
Debt Instrument, Maturity Date		Dec. 31, 2019
Debt Instrument, Face Amount		$ 400,000,000
Long-term Debt, Gross		$ 399,941,000	399,873,000
Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.625%
Debt Instrument, Maturity Date		Dec. 31, 2017
Debt Instrument, Face Amount		$ 300,000,000
Syndicated Credit Facility $850 Million [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		850,000,000
Long-term Line of Credit	[1]	$ 18,153,000	$ 95,564,000
[1]	Represents issued but undrawn letters of credit. There was no cash borrowed for the periods presented.

Collateral Finance and Securi_3

Collateral Finance and Securitization Notes Collateral Finance and Securitization Notes (List of Collateral Finance and Securitization Notes) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Collateralized Financings	$ 681,961	$ 783,938
Debt Issuance Cost	(18,651)	(20,405)
Timerberlake Financial [Member]
Collateralized Financings	368,207	411,951
Reinsurance Group Of America Barbados [Member]
Collateralized Financings	131,602	159,100
Chesterfield Financial Holdings LLC [Member]
Collateralized Financings	185,700	217,800
Secured Debt [Member]
Debt Issuance Cost	$ (3,548)	$ (4,913)

Collateral Finance and Securi_4

Collateral Finance and Securitization Notes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2006
Collateral Finance Facility [Line Items]
Debt Instrument, Face Amount				$ 850,000,000
Direct investment in subsidiary				$ 112,800,000
Assets Held-in-trust	$ 767,900,000	$ 841,500,000
Amount Held In Debt Service Coverage Account	57,100,000	39,700,000
Collateral Financing Expense	29,699,000	28,636,000	$ 25,827,000
Debt Issuance Cost	18,651,000	20,405,000
Reinsurance Group Of America Barbados [Member]
Collateral Finance Facility [Line Items]
Collateral Financing Expense	$ 5,100,000	4,200,000	4,000,000
Timerberlake Financial [Member]
Collateral Finance Facility [Line Items]
Debt Instrument, Issuance Date	Jun. 1, 2006
Collateral Financing Expense	$ 9,400,000	6,400,000	4,200,000
Chesterfield Financial Holdings LLC [Member]
Collateral Finance Facility [Line Items]
Debt Instrument, Face Amount	300,000,000
Assets Held-in-trust	13,500,000	19,400,000
Collateral Financing Expense	$ 9,500,000	$ 11,300,000	$ 13,100,000
Debt Instrument, Interest Rate, Stated Percentage	4.50%
Minimum [Member]
Collateral Finance Facility [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 35,000,000

Segment Information (Reconcilia

Segment Information (Reconciliation of Revenue from Segments to Consolidated) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 3,278,518	$ 3,227,531	$ 3,195,908	$ 3,173,707	$ 3,232,443	$ 3,145,310	$ 3,129,276	$ 3,008,740	$ 12,875,664	$ 12,515,769	$ 11,521,511
Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									7,202,978	7,250,549	6,805,414
Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,272,992	1,152,458	1,164,942
EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,844,491	1,673,146	1,535,667
Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									2,471,327	2,284,461	1,834,532
Corporate and Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									83,876	155,155	180,956
Life Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									6,295,733	6,100,171	5,964,968
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,224,404	1,103,520	1,118,004
Life Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									1,494,605	1,362,075	1,195,149
Life Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									2,416,848	2,210,686	1,771,150
Other Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									907,245	1,150,378	840,446
Other Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									48,588	48,938	46,938
Other Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									349,886	311,071	340,518
Other Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									$ 54,479	$ 73,775	$ 63,382

Segment Information (Reconcil_2

Segment Information (Reconciliation of Income before Income Taxes from Segments to Consolidated) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	$ 137,946	$ 322,661	$ 247,288	$ 137,925	$ 255,494	$ 340,162	$ 339,315	$ 207,844	$ 845,820	$ 1,142,815	$ 1,043,946
Americas [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									536,888	775,018	654,481
Canada Segment Reporting Information [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									121,884	136,861	142,650
EMEA [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									251,506	194,000	168,066
Asia Pacific [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									171,535	161,916	117,991
Corporate and Other [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									(235,993)	(124,980)	(39,242)
Life Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									286,410	373,434	371,101
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									112,308	120,218	134,705
Life Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									55,119	70,486	30,059
Life Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									177,501	148,786	113,928
Other Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									250,478	401,584	283,380
Other Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									9,576	16,643	7,945
Other Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									196,387	123,514	138,007
Other Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									$ (5,966)	$ 13,130	$ 4,063

Segment Information (Reconcil_3

Segment Information (Reconciliation of Interest Expense from Segments to Consolidated) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Interest expense	$ 147,355	$ 146,025	$ 137,623
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Interest expense	$ 147,355	$ 146,025	$ 137,623

Segment Information (Reconcil_4

Segment Information (Reconciliation of Depreciation and Amortization from Segment to Consolidated) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	$ 574,362	$ 705,964	$ 557,055
Americas [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	367,861	493,749	427,292
Canada Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	22,118	24,067	22,181
EMEA [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	45,524	35,091	46,634
Asia Pacific [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	116,755	115,781	47,054
Corporate and Other [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	22,104	37,276	13,894
Life Insurance Product Line [Member] | Americas [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	272,555	284,959	271,732
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	22,109	24,057	22,170
Life Insurance Product Line [Member] | EMEA [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	45,140	35,000	46,562
Life Insurance Product Line [Member] | Asia Pacific [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	114,870	114,333	45,562
Other Insurance Product Line [Member] | Americas [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	95,306	208,790	155,560
Other Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	9	10	11
Other Insurance Product Line [Member] | EMEA [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	384	91	72
Other Insurance Product Line [Member] | Asia Pacific [Member]
Depreciation, Depletion and Amortization [Abstract]
Depreciation, Depletion and Amortization, Nonproduction	$ 1,885	$ 1,448	$ 1,492

Segment Information (Reconcil_5

Segment Information (Reconciliation of Assets from Segment to Consolidated) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 64,535,245	$ 60,514,818
Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	39,106,169	34,562,629
Canada Segment Reporting Information [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,354,792	4,287,824
EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	8,380,703	8,374,488
Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	6,861,723	6,114,027
Corporate and Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,831,858	7,175,850
Life Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	19,235,781	18,603,423
Life Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,200,792	4,161,452
Life Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	3,643,174	3,099,495
Life Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	5,680,978	4,915,442
Other Insurance Product Line [Member] | Americas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	19,870,388	15,959,206
Other Insurance Product Line [Member] | Canada Segment Reporting Information [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	154,000	126,372
Other Insurance Product Line [Member] | EMEA [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	4,737,529	5,274,993
Other Insurance Product Line [Member] | Asia Pacific [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 1,180,745	$ 1,198,585

Policy Claims and Benefits (Cla

Policy Claims and Benefits (Claims Development) (Details) - Life Insurance Product Line [Member] - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net		$ 1,597,776
Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	1,240,936
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	1,869,953
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	[1]	112,373
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	[1]	741,390
Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	2,365,538
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	3,043,900
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	[1]	178,024
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	[1]	856,386
Short-duration Insurance Contracts, Accident Year 2012 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	274,830	$ 259,917	$ 243,549	$ 222,987	$ 185,322	$ 135,322	$ 49,321
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	309,287	303,340	294,265	286,632	283,316	279,008	207,882
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		10,352
Short-duration Insurance Contracts, Accident Year 2012 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	268,073	263,565	258,297	252,018	243,890	222,139	109,323
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	296,717	297,688	299,098	298,262	297,037	309,119	$ 322,579
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		0
Short-duration Insurance Contracts, Accident Year 2013 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	282,961	261,299	235,923	209,347	144,247	49,805
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	328,017	314,283	301,168	303,779	313,126	292,769
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		16,728
Short-duration Insurance Contracts, Accident Year 2013 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	297,126	292,067	285,817	277,130	248,828	114,457
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	336,323	336,436	336,552	338,977	332,907	$ 349,262
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		24
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	228,873	206,176	177,439	135,668	34,519
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	284,237	272,247	265,431	300,336	277,049
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		21,339
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	356,026	349,078	337,081	304,578	128,813
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	396,010	397,151	396,383	411,373	$ 407,953
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		272
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	202,273	167,350	118,579	48,962
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	267,292	251,650	257,146	278,491
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		32,392
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	422,102	407,282	360,658	146,196
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	461,947	465,167	460,917	$ 459,524
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		1,505
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	133,091	97,769	38,310
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	212,722	211,425	227,653
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		40,376
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	436,892	392,517	184,940
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	500,725	499,785	$ 500,843
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		4,885
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	87,037	35,442
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	214,707	216,499
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		63,383
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	402,759	189,853
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	513,722	$ 485,442
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		27,190
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Asia Pacific [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	31,871
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	253,691
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		156,761
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Americas [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	[1]	182,560
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	[1]	538,456
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net		$ 234,548
[1]	2012-2017 Unaudited.

Policy Claims and Benefits Poli

Policy Claims and Benefits Policy Claims and Benefits (Schedule of Historical Claims Duration) (Details) - Life Insurance Product Line [Member]	Dec. 31, 2018
Americas [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	34.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	41.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	8.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	2.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	1.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	1.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	1.50%
Asia Pacific [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	15.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	28.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	17.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	10.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	7.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	5.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	4.80%

Policy Claims and Benefits (Rec

Policy Claims and Benefits (Reconciliation of Claims Development to Liability) (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments		$ 432,582	$ 455,547	$ 394,821	$ 405,583
Short-duration Insurance Contract, Discounted Liability, Discount		119,661
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Other Reconciling Item		2,168,298
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Aggregate Reconciling Items		4,416,370
Liability for Claims and Claims Adjustment Expense		6,584,668	$ 5,896,469	$ 5,180,802	$ 4,977,836
Canada Segment Reporting Information [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Other Reconciling Item		128,831
EMEA [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Other Reconciling Item		383,936
Corporate And Other Segment Reporting Information [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Other Reconciling Item		177,416
Life Insurance Product Line [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net		1,597,776
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments		16,121
Short-duration Insurance Contract, Discounted Liability, Discount for Reinsurance		(141,689)
Short-duration Insurance Contracts, Liability for Unpaid Claims and Claims Adjustment Expense, Accumulated Unallocated Claim Adjustment Expense		5,907
Life Insurance Product Line [Member] | Americas [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	[1]	856,386
Life Insurance Product Line [Member] | Asia Pacific [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	[1]	$ 741,390
[1]	2012-2017 Unaudited.

Policy Claims and Benefits Po_2

Policy Claims and Benefits Policy Claims and Benefits (Rollforward of Claims and Claim Adjustment Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Liability for Claims and Claims Adjustment Expense Beginning Balance	$ 5,896,469	$ 5,180,802	$ 4,977,836
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments, Beginning Balance	(455,547)	(394,821)	(405,583)
Liability For Unpaid Claims And Claims Adjustment Expense Net Of Recoverable, Beginning Balance	5,440,922	4,785,981	4,572,253
Current Year Claims and Claims Adjustment Expense	10,048,866	8,911,640	8,562,036
Prior Year Claims and Claims Adjustment Expense	131,181	14,364	(134,765)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	10,180,047	8,926,004	8,427,271
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	(4,602,535)	(4,513,606)	(4,385,839)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	(4,691,722)	(4,004,038)	(3,777,137)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	(9,294,257)	(8,517,644)	(8,162,976)
Interest On Liability For Policy And Contract Claims	24,802	19,443	18,151
Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss)	(199,428)	227,138	(68,718)
Liability for Unpaid Claims and Claims Adjustment Expense Other	(174,626)	246,581	(50,567)
Liability For Unpaid Claims And Claims Adjustment Expense Net Of Recoverable, Ending Balance	6,152,086	5,440,922	4,785,981
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments, Ending Balance	432,582	455,547	394,821
Liability for Claims and Claims Adjustment Expense, Ending Balance	$ 6,584,668	$ 5,896,469	$ 5,180,802

Equity Equity (Common Stock Cha

Equity Equity (Common Stock Changes in Number of Shares Issued, Held in Treasury and Oustanding) (Details) - shares		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common Stock, Shares, Issued		79,137,758	79,137,758
Treasury Stock, Shares, Acquired				(1,356,892)
Common Stock Issuable [Member]
Class of Stock [Line Items]
Common Stock, Shares, Issued		79,137,758	79,137,758	79,137,758	79,137,758
Stock Based Compensation Shares	[1]	0	0	0
Treasury Stock, Shares, Acquired		0	0	0
Common Stock Held In Treasury [Member]
Class of Stock [Line Items]
Common Stock, Shares, Issued		16,323,390	14,685,663	14,835,256	13,933,232
Stock Based Compensation Shares	[1]	(294,328)	(358,273)	(454,868)
Treasury Stock, Shares, Acquired		(1,932,055)	(208,680)	(1,356,892)
Common Stock Outstanding [Member]
Class of Stock [Line Items]
Common Stock, Shares, Issued		62,814,368	64,452,095	64,302,502	65,204,526
Stock Based Compensation Shares	[1]	(294,328)	(358,273)	(454,868)
Treasury Stock, Shares, Acquired		(1,932,055)	(208,680)	(1,356,892)
[1]	Represents net shares issued from treasury pursuant to the Company’s stock-based compensation programs.

Equity Equity (Share Repurchase

Equity Equity (Share Repurchase Program) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired			1,356,892
Treasury Stock, Value, Acquired, Cost Method	$ 299,679	$ 43,508	$ 122,916
Treasury Stock Value Acquired Cost Method Repurchase Agreement			$ 116,500
Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired	1,932,055,000	208,680,000
Treasury Stock, Value, Acquired, Cost Method	$ 283,524	$ 26,897
Treasury Stock Acquired, Average Cost Per Share	$ 146,750	$ 128,890
Treasury Stock Shares Acquired Share Repurchase Authorization	2,140,735,000
Treasury Stock Value Acquired Cost Method Repurchase Agreement	$ 310,421

Equity (Components of Other Com

Equity (Components of Other Comprehensive Income) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax		$ (148,018)	$ 74,926	$ 39,925
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax		(759)	25,369	(24,663)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		(148,777)	100,295	15,262
Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Foreign Currency Swap, Before Reclassification and Tax		87,344	(47,953)	(10,234)
Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Foreign Currency Swap Tax		(18,342)	16,784	3,582
Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Foreign Currency Swap Net Of Tax		69,002	(31,169)	(6,652)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax		(60,674)	26,973	29,691
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax		(19,101)	42,153	(21,081)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		(79,775)	69,126	8,610
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax	[1]	(1,834,656)	1,029,591	641,606
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	[1]	393,653	(313,729)	(180,448)
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	[1]	(1,441,003)	715,862	461,158
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, before Tax	[1]	(122,221)	25,039	65,798
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax	[1]	25,720	(7,011)	(23,029)
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax	[1]	(96,501)	18,028	42,769
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments and Tax	[1]	(1,712,435)	1,004,552	575,808
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	[1]	367,933	(306,718)	(157,419)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	[1]	(1,344,502)	697,834	418,389
Other than Temporary Impairment Loss, Investments, Portion in Other Comprehensive Loss, before Tax, Portion Attributable to Parent, Available-for-sale Securities			(375)	(1,457)
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Tax, Portion Attributable to Parent, Available-for-sale Securities			(131)	(510)
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Portion Attributable to Parent, Available-for-sale Securities			244	947
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax		(947)	11,717	444
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax		182	(4,095)	(149)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax		(765)	7,622	295
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		1,063	(10,587)	4,427
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax		(316)	3,691	(1,623)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		747	(6,896)	2,804
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax		116	1,130	4,871
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax		(134)	(404)	(1,772)
Defined benefit pension and postretirement plan adjustments		(18)	726	3,099
Other Comprehensive Income (Loss), before Tax		(1,772,993)	1,033,030	611,827
Other Comprehensive Income (Loss), Tax		348,698	(265,100)	(180,782)
Other Comprehensive Income (Loss), Net of Tax		$ (1,424,295)	$ 767,930	$ 431,045
[1]	Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.

Equity (Components of Net Unrea

Equity (Components of Net Unrealized Appreciation Depreciation of Balances Carried at Fair Value) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Comprehensive Income Net Of Tax [Line Items]
Fixed maturity securities available-for-sale		$ 39,992,346	$ 38,150,820
Other invested assets		1,915,297	1,505,332
Deferred policy acquisition costs		3,397,770	3,239,824	$ 3,338,605	$ 3,392,437
Accumulated Other Comprehensive Income Loss Change In Component During Period		(1,712,435)	1,004,927	577,265
Change In Net Unrealized Appreciation Depreciation [Member]
Comprehensive Income Net Of Tax [Line Items]
Fixed maturity securities available-for-sale		(1,759,230)	987,570	561,906
Other invested assets	[1]	20,187	25,577	18,900
Effect On Unrealized Appreciation Depreciation [Member]
Comprehensive Income Net Of Tax [Line Items]
Deferred policy acquisition costs		$ 26,608	$ (8,220)	$ (3,541)
[1]	Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.

Equity (Balance of and Changes

Equity (Balance of and Changes in Each Component of AOCI) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance, beginning of year		$ 2,063,631	$ 1,139,329	$ 708,284
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		(1,926,681)	1,062,087	675,627
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		153,688	(29,057)	(63,800)
Other Comprehensive Income (Loss), Tax		348,698	(265,100)	(180,782)
Balance, end of year		636,763	2,063,631	1,139,329
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		2,600	156,400
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance, beginning of year		(86,350)	(172,541)	(181,151)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		(60,674)	26,973	29,691
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0	0	0
Other Comprehensive Income (Loss), Tax		(19,101)	42,153	(21,081)
Balance, end of year		(168,698)	(86,350)	(172,541)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance, beginning of year	[1]	2,200,661	1,355,033	935,697
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	[1]	(1,860,789)	1,039,387	646,887
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	(148,354)	34,460	69,622
Other Comprehensive Income (Loss), Tax	[1]	367,933	(306,849)	(157,929)
Balance, end of year	[1]	856,159	2,200,661	1,355,033
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance, beginning of year		(50,680)	(43,163)	(46,262)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		(5,218)	(4,273)	(951)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(5,334)	(5,403)	(5,822)
Other Comprehensive Income (Loss), Tax		(134)	(404)	(1,772)
Balance, end of year		(50,698)	(50,680)	$ (43,163)
Accounting Standards Update 2018 02 [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		(2,020)	17,723
Accounting Standards Update 2018 02 [Member] | Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		(2,573)	17,065
Accounting Standards Update 2018 02 [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		0	147,550
Accounting Standards Update 2018 02 [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		0	(8,243)
Accounting Standards Update 2018 02 [Member] | AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ (2,573)	$ 156,372
[1]	Includes cash flow hedges of $8,788, $2,619 and $(2,496) as of December 31, 2018, 2017 and 2016, respectively. See Note 5 for additional information on cash flow hedges.

Equity Equity (Balance of and C

Equity Equity (Balance of and Changes in Each Component of AOCI) (Footnote) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$ 8,788	$ 2,619	$ (2,496)	$ (29,397)

Equity (Schedule of Reclassific

Equity (Schedule of Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other investment related gains (losses), net										$ (141,594)	$ 210,519	$ 132,926
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest										0	0	(74)
Investment income, net of related expenses										2,138,525	2,154,651	1,911,886
Deferred Policy Acquisition Cost, Amortization Expense, Unrealized Investment Gains (Losses)										(26,608)	8,220	3,541
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax										947	(11,717)	(444)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax										(1,063)	10,587	(4,427)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		$ 137,946	$ 322,661	$ 247,288	$ 137,925	$ 255,494	$ 340,162	$ 339,315	$ 207,844	845,820	1,142,815	1,043,946
Income Tax Expense (Benefit)										(129,978)	679,366	(342,503)
Net Income (Loss) Attributable to Parent		$ 110,039	$ 301,199	$ 204,374	$ 100,230	$ 1,216,888	$ 227,591	$ 232,190	$ 145,512	715,842	1,822,181	$ 701,443
Amortization Of Unrealized Pension And Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	[1]									971	(971)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	[1]									(6,305)	(6,374)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest										(5,334)	(5,403)
Income Tax Expense (Benefit)										1,176	1,891
Net Income (Loss) Attributable to Parent										(4,158)	(3,512)
Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other investment related gains (losses), net										(122,221)	25,039
Deferred Policy Acquisition Cost, Amortization Expense, Unrealized Investment Gains (Losses)	[2]									(26,608)	8,220
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest										(148,354)	34,460
Income Tax Expense (Benefit)										31,208	(10,308)
Net Income (Loss) Attributable to Parent										(117,146)	24,152
Amounts Reclassified From AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income (Loss) Attributable to Parent										(121,304)	20,640
Interest Rate Options [Member] | Unrealized Gains Losses On Available For Sale Securities [Member] | Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[3]									183	(79)
Currency Swap [Member] | Unrealized Gains Losses On Available For Sale Securities [Member] | Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[3]									292	380
Forward Contracts [Member] | Unrealized Gains Losses On Available For Sale Securities [Member] | Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[3]									$ 0	$ 900
[1]	See Note 10 for information on employee benefit plans.
[2]	See Note 8 for information on deferred policy acquisition costs.
[3]	See Note 5 for information on cash flow hedges.

Equity (Narrative) (Details)

Equity (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Stock Repurchase Program, Authorized Amount		$ 400,000	$ 400,000
Treasury Stock, Shares, Acquired			1,356,892
Treasury Stock Value Acquired Cost Method Repurchase Agreement			$ 116,500
Treasury Stock, Value, Acquired, Cost Method	$ 299,679	$ 43,508	$ 122,916

Equity Based Compensation (Disc

Equity Based Compensation (Disclosure of Share-based Compensation Arrangements by Share-based Payment Award) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options, Grants in Period, Weighted Average Exercise Price	$ 150.87	$ 129.72	$ 93.53
Options, Outstanding, Intrinsic Value	$ 126.7
Options, Exercisable, Intrinsic Value	$ 110.1
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Number, Beginning Balance	2,309,769,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	164,889,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	(286,874,000)
Forfeited	(17,341,000)
Outstanding, Number, Ending Balance	2,170,443,000	2,309,769,000
Options exercisable	1,633,182,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options, Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 75.17
Options, Grants in Period, Weighted Average Exercise Price	150.87
Exercised / Lapsed	59.45
Forfeited	119.63
Options, Outstanding, Weighted Average Exercise Price, End of Period	82.65	$ 75.17
Options exercisable	$ 73.09

Equity Based Compensation (Di_2

Equity Based Compensation (Disclosure of Share-based Compensation Shares Authorized under Stock Option Plans by Exercise Price Range) (Details)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding | shares	2,170,443,000
Options Outstanding, Weighted-Average Remaining Contractual Life	5 years 3 months
Options Outstanding, Weighted Average Exercise Price	$ 82.65
Options Exercisable | shares	1,633,182,000
Options Exercisable, Weighted-Average Exercise Price	$ 73.09
$0.00 - $49.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding | shares	163,805,000
Options Outstanding, Weighted-Average Remaining Contractual Life	11 months
Options Outstanding, Weighted Average Exercise Price	$ 43.97
Options Exercisable | shares	163,805,000
Options Exercisable, Weighted-Average Exercise Price	$ 43.97
Exercise Price Range, Lower Range Limit	25
Exercise Price Range, Upper Range Limit	$ 44.99
$50.00 - $59.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding | shares	775,518,000
Options Outstanding, Weighted-Average Remaining Contractual Life	3 years 6 months
Options Outstanding, Weighted Average Exercise Price	$ 58.26
Options Exercisable | shares	775,518,000
Options Exercisable, Weighted-Average Exercise Price	$ 58.26
$60.00 - $69.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding | shares	839,000
Options Outstanding, Weighted-Average Remaining Contractual Life	4 years 2 months
Options Outstanding, Weighted Average Exercise Price	$ 60.24
Options Exercisable | shares	839,000
Options Exercisable, Weighted-Average Exercise Price	$ 60.24
Exercise Price Range, Lower Range Limit	45
Exercise Price Range, Upper Range Limit	$ 54.99
$70.00 - $79.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding | shares	159,593,000
Options Outstanding, Weighted-Average Remaining Contractual Life	5 years 2 months
Options Outstanding, Weighted Average Exercise Price	$ 78.48
Options Exercisable | shares	159,593,000
Options Exercisable, Weighted-Average Exercise Price	$ 78.48
Exercise Price Range, Lower Range Limit	$ 55
$90.00 plus [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding | shares	1,070,688,000
Options Outstanding, Weighted-Average Remaining Contractual Life	7 years 5 months
Options Outstanding, Weighted Average Exercise Price	$ 106.87
Options Exercisable | shares	533,427,000
Options Exercisable, Weighted-Average Exercise Price	$ 102

Equity Based Compensation (Weig

Equity Based Compensation (Weighted Average Assumptions) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.33%	1.26%	1.58%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	2.79%	2.32%	1.69%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	21.40%	22.80%	28.10%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	7 years	7 years	7 years
Options, Grants in Period, Weighted Average Exercise Price	$ 150.87	$ 129.72	$ 93.53
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 36.31	$ 31.57	$ 24.52

Equity Based Compensation (Summ

Equity Based Compensation (Summary of Performance Contingent Unit Activity) (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Number, Beginning Balance	463,259
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	110,042
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	170,080	137,083
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	7,350
Outstanding, Number, Ending Balance	395,871	463,259
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Number, Beginning Balance	77,358
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	20,393
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	28,023
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	2,729
Outstanding, Number, Ending Balance	66,999	77,358

Equity Based Compensation (Narr

Equity Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercises in Period, Total Intrinsic Value	$ 25.6	$ 42.1	$ 41.4
Performance Contingent Unit Share Payout	1.07	0.75
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	1 year 5 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 24.7
Performance Contingent Units Measurement Period	3 years
Allocated Share-based Compensation Expense	$ 30.1	$ 22.3	$ 33.1
Options, Grants in Period, Weighted Average Exercise Price	$ 150.87	$ 129.72	$ 93.53
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	286,874,000
Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	164,889,000
Options, Grants in Period, Weighted Average Exercise Price	$ 150.87
Flexible Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Of Shares Available For Grant	14,960,077
Flexible Stock Plan For Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Of Shares Available For Grant	412,500
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	170,080	137,083
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	110,042
Options, Grants in Period, Weighted Average Exercise Price	$ 150.87
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	28,023
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	20,393
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	1 year
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	5 years

Quarterly Results of Operatio_3

Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 3,278,518	$ 3,227,531	$ 3,195,908	$ 3,173,707	$ 3,232,443	$ 3,145,310	$ 3,129,276	$ 3,008,740	$ 12,875,664	$ 12,515,769	$ 11,521,511
Total benefits and expenses	3,140,572	2,904,870	2,948,620	3,035,782	2,976,949	2,805,148	2,789,961	2,800,896	12,029,844	11,372,954	10,477,565
Income before income taxes	137,946	322,661	247,288	137,925	255,494	340,162	339,315	207,844	845,820	1,142,815	1,043,946
Net Income (Loss) Attributable to Parent	$ 110,039	$ 301,199	$ 204,374	$ 100,230	$ 1,216,888	$ 227,591	$ 232,190	$ 145,512	$ 715,842	$ 1,822,181	$ 701,443
Basic earnings per share:
Earnings Per Share, Basic (in dollars per share)	$ 1.75	$ 4.76	$ 3.19	$ 1.55	$ 18.89	$ 3.53	$ 3.60	$ 2.26	$ 11.25	$ 28.28	$ 10.91
Earnings Per Share, Diluted (in dollars per share)	$ 1.72	$ 4.68	$ 3.13	$ 1.52	$ 18.49	$ 3.47	$ 3.54	$ 2.22	$ 11	$ 27.71	$ 10.79

Subsequent Event (Details)

Subsequent Event (Details) - USD ($) $ in Millions	Jan. 24, 2019	Dec. 31, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount		$ 400	$ 400
Subsequent Event [Member]
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount	$ 400

Summary of Investments Other _3

Summary of Investments Other Than Investments in Related Parties (Details) $ in Millions	Dec. 31, 2018USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	$ 53,121
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	54,205	[1]
Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	38,882
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	39,992
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	39,992	[1]
US Treasury and Government [Member] | Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	2,234
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	2,186
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	2,186	[1]
US States and Political Subdivisions Debt Securities [Member] | Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	721
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	752
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	752	[1]
Foreign Government Debt [Member] | Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	6,449	[2]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	7,635	[2]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	7,635	[1],[2]
Public Utility, Bonds [Member] | Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	2,876
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	2,909
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	2,909	[1]
Asset-backed Securities [Member] | Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	5,472
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	5,437
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	5,437	[1]
All Other Corporate Bonds [Member] | Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	21,130
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	21,073
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	21,073	[1]
Equity Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	108
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value	82
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	82	[1]
Mortgage Loans on Real Estate [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	4,966
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	4,966	[1]
Policy Loans [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	1,345
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	1,345	[1]
Funds Withheld At Interest [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	5,762
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	5,762	[1]
Short-term Investments [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	143
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	143	[1]
Other Invested Assets [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	1,915
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount	$ 1,915	[1]
[1]	Fixed maturity securities are classified as available-for-sale and carried at fair value.
[2]	Includes fixed maturities directly issued by foreign governments, supranational and foreign government-sponsored enterprises.

Condensed Financial Informati_3

Condensed Financial Information of The Registrant (Details) - USD ($)		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2006
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 2,806,524,000	$ 2,808,770,000
Debt Issuance Cost													(18,651,000)	(20,405,000)
Long-term debt													2,787,873,000	2,788,365,000
Assets
Fixed maturity securities available-for-sale													39,992,346,000	38,150,820,000
Short-term investments													142,598,000	93,304,000
Cash and cash equivalents		$ 1,889,733,000			$ 1,303,524,000	$ 1,303,524,000			$ 1,200,718,000	$ 1,303,524,000	$ 1,200,718,000	$ 1,525,275,000	1,889,733,000	1,303,524,000	$ 1,200,718,000	$ 1,525,275,000
Other assets													839,222,000	767,088,000
Total assets													64,535,245,000	60,514,818,000
Liabilities and Stockholders’ Equity
Other liabilities													1,396,200,000	1,102,975,000
Total stockholders equity													8,450,553,000	9,569,535,000	7,093,082,000	6,135,381,000
Total liabilities and stockholders’ equity													64,535,245,000	60,514,818,000
CONSOLIDATED STATEMENTS OF INCOME
Total investment related gains (losses), net										(170,088,000)	167,880,000	94,195,000
Income Tax Expense (Benefit)										129,978,000	(679,366,000)	342,503,000
Net Income (Loss) Attributable to Parent		110,039,000	$ 301,199,000	$ 204,374,000	100,230,000	1,216,888,000	$ 227,591,000	$ 232,190,000	145,512,000	715,842,000	1,822,181,000	701,443,000
Other Comprehensive Income (Loss), Net of Tax										(1,424,295,000)	767,930,000	431,045,000
Total comprehensive income (loss)										(708,453,000)	2,590,111,000	1,132,488,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount																	$ 850,000,000
Cash flows from operating activities
Net Income (Loss) Attributable to Parent		110,039,000	$ 301,199,000	$ 204,374,000	100,230,000	1,216,888,000	$ 227,591,000	$ 232,190,000	145,512,000	715,842,000	1,822,181,000	701,443,000
Other, net										(1,268,000)	24,216,000	117,949,000
Net cash provided by operating activities										1,581,121,000	1,982,308,000	1,465,718,000
Cash flows from investing activities
Sales of fixed maturity securities available-for-sale										9,339,632,000	7,308,608,000	4,584,828,000
Payments to Acquire Businesses, Net of Cash Acquired										(31,441,000)	0	0
Payments for (Proceeds from) Short-term Investments										129,329,000	52,302,000	465,628,000
Payments for (Proceeds from) Other Investing Activities										(365,242,000)	(121,206,000)	(97,790,000)
Net cash used in investing activities										(636,552,000)	(1,607,573,000)	(2,825,726,000)
Cash flows from financing activities
Dividends to stockholders										(140,110,000)	(117,291,000)	(100,371,000)
Purchases of treasury stock										(299,679,000)	(43,508,000)	(122,916,000)
Excess tax benefits from share-based payment arrangement cash flow										0	0	162,000
Exercise of stock options, net										3,459,000	7,292,000	15,321,000
Maturities of Senior Debt										2,690,000	302,582,000	2,479,000
Proceeds from affiliated long-term debt issuance										0	0	(799,984,000)
Payments Of Debt Issuance Costs										0	0	(8,766,000)
Net cash used in financing activities										(321,973,000)	(324,622,000)	1,055,389,000
Change in cash and cash equivalents										586,209,000	102,806,000	(324,557,000)
Cash and cash equivalents, beginning of period					1,303,524,000				1,200,718,000	1,303,524,000	1,200,718,000	1,525,275,000
Cash and cash equivalents, end of period		1,889,733,000				1,303,524,000				1,889,733,000	1,303,524,000	1,200,718,000
Supplementary information:
Interest paid										170,191,000	173,471,000	156,727,000
Income taxes paid, net of refunds										141,703,000	37,098,000	61,085,000
Cash Acquired from Acquisition										4,988,000	0	0
Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													2,797,357,000	2,796,913,000
Debt Issuance Cost													(19,601,000)	(21,334,000)
Long-term debt	[1]												2,777,756,000	2,775,579,000
Assets
Fixed maturity securities available-for-sale													595,303,000	710,303,000
Short-term investments													42,906,000	54,517,000
Cash and cash equivalents		20,641,000			15,176,000	15,176,000			43,718,000	15,176,000	43,718,000	39,452,000	20,641,000	15,176,000	$ 43,718,000	$ 39,452,000
Investments In Subsidiary													11,033,195,000	12,043,911,000
Loans and Leases Receivable, Related Parties													1,010,000,000	1,010,000,000
Other assets													239,643,000	234,707,000
Total assets													12,941,688,000	14,068,614,000
Liabilities and Stockholders’ Equity
Long-term debt - affiliated	[2]												500,000,000	500,000,000
Other liabilities													1,213,379,000	1,223,500,000
Total stockholders equity													8,450,553,000	9,569,535,000
Total liabilities and stockholders’ equity													12,941,688,000	14,068,614,000
CONSOLIDATED STATEMENTS OF INCOME
Interest and Dividend Income, Operating	[3]									575,833,000	131,067,000	602,830,000
Total investment related gains (losses), net										(5,392,000)	(5,187,000)	203,000
Operating Expenses										(35,912,000)	(20,517,000)	(20,742,000)
Interest and Debt Expense										(181,364,000)	(177,417,000)	(168,924,000)
Income (loss) before income tax and undistributed earnings of subsidiaries										353,165,000	(72,054,000)	413,367,000
Income Tax Expense (Benefit)										(37,294,000)	65,882,000	(23,911,000)
Net income (loss) before undistributed earnings of subsidiaries										390,459,000	(137,936,000)	437,278,000
Equity In Undistributed Earnings Of Subsidiaries										325,383,000	1,960,117,000	264,165,000
Net Income (Loss) Attributable to Parent										715,842,000	1,822,181,000	701,443,000
Other Comprehensive Income (Loss), Net of Tax										21,455,000	(7,672,000)	5,531,000
Total comprehensive income (loss)										737,297,000	1,814,509,000	706,974,000
Debt Disclosure [Abstract]
Proceeds from Dividends Received										0	478,602,000	196,445,000
Long-term Debt													500,000,000	500,000,000
Cash flows from operating activities
Net Income (Loss) Attributable to Parent										715,842,000	1,822,181,000	701,443,000
Equity Net Earnings Subsidiaries										(325,383,000)	(1,960,117,000)	(264,165,000)
Other, net										36,754,000	57,677,000	(63,795,000)
Net cash provided by operating activities										427,213,000	(80,259,000)	373,483,000
Cash flows from investing activities
Sales of fixed maturity securities available-for-sale										482,324,000	514,508,000	228,383,000
Purchases of fixed maturity securities available-for-sale										(383,392,000)	(75,000,000)	(984,397,000)
Purchases Of Subsidiary Debt Securities										0	40,000,000	20,000,000
Payments for (Proceeds from) Short-term Investments										0	0	102,508,000
Payments for (Proceeds from) Other Investing Activities										44,000	125,506,000	(109,914,000)
Capital Contributions To Subsidiaries										(82,150,000)	(62,500,000)	(314,142,000)
Net cash used in investing activities										16,826,000	542,514,000	(1,057,562,000)
Cash flows from financing activities
Dividends to stockholders										(140,110,000)	(117,291,000)	(100,371,000)
Purchases of treasury stock										(299,679,000)	(43,508,000)	(122,916,000)
Exercise of stock options, net										3,459,000	7,292,000	15,321,000
Net Change In Cash Collateral For Loaned Securities										(2,244,000)	(37,290,000)	105,093,000
Maturities of Senior Debt										0	(300,000,000)	0
Proceeds from affiliated long-term debt issuance										0	0	(799,984,000)
Payments Of Debt Issuance Costs										0	0	(8,766,000)
Net cash used in financing activities										(438,574,000)	(490,797,000)	688,345,000
Change in cash and cash equivalents										5,465,000	(28,542,000)	4,266,000
Cash and cash equivalents, beginning of period					$ 15,176,000				$ 43,718,000	15,176,000	43,718,000	39,452,000
Cash and cash equivalents, end of period		$ 20,641,000				$ 15,176,000				20,641,000	15,176,000	43,718,000
Supplementary information:
Interest paid										176,236,000	185,554,000	169,860,000
Income taxes paid, net of refunds										93,000,000	8,248,000	1,500,000
Cash Acquired from Acquisition										0	$ 0	$ 529,000
Senior Notes Due 2017 [Member]
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 300,000,000
Debt Instrument, Interest Rate, Stated Percentage													5.625%
Senior Notes Due 2017 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Repayments of Long-term Debt										300,000,000
Senior Notes Due 2019 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 399,941,000	399,873,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													6.45%
Senior Notes Due 2019 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 399,941,000	399,873,000
Debt Disclosure [Abstract]
Repayments of Long-term Debt										$ 400,000,000
Senior Notes Due 2021 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													399,466,000	399,245,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													5.00%
Senior Notes Due 2021 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 399,466,000	399,245,000
Senior Notes Due 2023 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													399,288,000	399,138,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													4.70%
Senior Notes Due 2023 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 399,289,000	399,138,000
Senior Notes Due 2026 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													399,988,000	399,987,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													3.95%
Senior Notes Due 2026 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 399,987,000	399,987,000
Subordinated Debentures Due 2042 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													400,000,000	400,000,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													6.20%
Subordinated Debentures Due 2042 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Subordinated Debentures Due 2056 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													400,000,000	400,000,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													5.75%
Subordinated Debentures Due 2056 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Junior Subordinated Debentures Due 2065 [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													318,743,000	318,740,000
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													4.82%
Junior Subordinated Debentures Due 2065 [Member] | Parent Company [Member]
Supplemental Condensed Financial Information Of The Registrant [Line Items]
Long-term Debt, Gross													$ 398,674,000	$ 398,670,000
[1]	Long-term debt - unaffiliated consists of the following: 2018 2017$400 million 6.45% Senior Notes due 2019 $399,941 $399,873$400 million 5.00% Senior Notes due 2021 399,466 399,245$400 million 4.70% Senior Notes due 2023 399,289 399,138$400 million 3.95% Senior Notes due 2026 399,987 399,987$400 million 6.20% Subordinated Debentures due 2042 400,000 400,000$400 million 5.75% Subordinated Debentures due 2056 400,000 400,000$400 million Variable Rate Junior Subordinated Debentures due 2065 398,674 398,670Subtotal 2,797,357 2,796,913Unamortized debt issue costs (19,601) (21,334)Total $2,777,756 $2,775,579Repayments of long-term debt—unaffiliated due over the next five years total $400,000 in 2019, $400,000 in 2021 and $400,000 in 2023.
[2]	Long-term debt—affiliated in 2018 and 2017 and consists of $500,000 of subordinated debt issued to various operating subsidiaries.
[3]	Interest/dividend income includes $450,000 and $478,602 of cash dividends received from consolidated subsidiaries in 2018 and 2016, respectively. In 2017 there were no cash dividends received from consolidated subsidiaries.

Supplementary Insurance Infor_3

Supplementary Insurance Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		$ 3,397,770	$ 3,239,824
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		43,289,926	38,590,883
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		5,642,755	4,992,074
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		10,543,776	9,841,130	$ 9,248,871
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		2,138,525	2,154,651	1,911,886
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		9,744,133	9,020,957	8,358,066
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		423,038	502,866	381,192
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	1,862,673	1,849,131	1,738,307
US Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		1,824,874	1,818,572
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		11,727,505	11,343,921
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		1,948,335	1,814,018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		5,533,256	5,356,321	5,249,571
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		729,757	728,073	699,833
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		5,130,795	4,842,412	4,717,850
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		180,407	191,725	177,255
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	698,121	692,600	698,762
US Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		420,154	405,623
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		19,420,906	15,127,529
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		20,855	17,876
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		27,203	23,683	24,349
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		706,624	778,473	631,097
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		442,071	458,368	333,107
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		108,697	185,280	133,501
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	105,999	105,146	90,458
Canada Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		192,661	212,345
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		2,929,568	3,041,790
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		182,343	206,655
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		1,024,021	901,976	928,642
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		199,412	189,018	178,927
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		847,828	757,912	707,428
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		13,097	12,426	10,621
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	251,171	212,964	265,250
Canada Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		0	0
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		25,574	27,908
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		34,471	1,040
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		43,372	38,229	38,701
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		1,334	5,115	2,692
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		36,808	29,639	36,275
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		0	0	0
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	2,204	2,656	2,718
EMEA Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		239,161	229,150
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		1,110,194	1,075,786
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		977,530	882,744
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		1,423,199	1,301,640	1,140,062
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		66,242	55,511	50,301
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		1,233,458	1,096,211	999,005
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		26,915	20,570	33,795
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	179,113	174,808	132,290
EMEA Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		0	0
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		4,540,751	4,741,983
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		34,514	38,044
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		195,333	163,720	180,271
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		133,855	123,258	125,282
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		116,492	153,874	178,014
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		0	0	0
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	37,007	33,683	24,497
Asia Pacific Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		702,439	552,947
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		1,738,199	1,611,633
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		2,436,473	2,017,920
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		2,296,435	2,053,029	1,681,505
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		95,521	91,675	83,049
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		1,885,355	1,635,728	1,345,951
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		92,231	91,477	24,597
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	261,761	334,695	286,674
Asia Pacific Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		18,481	21,187
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		1,043,375	1,118,012
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		2,365	6,885
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		866	2,419	5,428
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		40,729	34,529	23,648
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		39,726	40,467	37,976
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		1,691	1,388	1,423
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	19,028	18,790	19,920
Corporate And Other Segment Reporting Information [Member]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost		0	0
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense		753,854	502,321
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable		5,869	6,892
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue		91	113	342
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income		165,051	148,999	117,057
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses		11,600	6,346	2,460
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost		0	0	0
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense	[1]	$ 308,269	$ 273,789	$ 217,738
[1]	Includes policy acquisition costs and other insurance expenses, excluding amortization of DAC. Also includes other operating expenses, interest expense, and collateral finance and securitization expense.

Supplemental Schedule of Rein_3

Supplemental Schedule of Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums, Life Insurance in Force	$ 1,363,000	$ 1,462,000	$ 1,576,000
Ceded Premiums, Life Insurance in Force	186,172,000	205,529,000	214,727,000
Assumed Premiums, Life Insurance in Force	3,329,181,000	3,297,275,000	3,062,525,000
Premiums, Net, Life Insurance in Force	$ 3,144,372,000	$ 3,093,208,000	$ 2,849,374,000
Life Insurance in Force Premiums, Percentage Assumed to Net	105.90%	106.60%	107.50%
Direct Premiums Earned	$ 62,526	$ 61,571	$ 57,562
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	860,034	862,903	858,278
Assumed Premiums Earned	11,341,284	10,642,462	10,049,587
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 10,543,776	$ 9,841,130	$ 9,248,871
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	107.60%	108.10%	108.70%
US Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 31,600	$ 30,500	$ 31,600
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	593,700	610,400	616,000
Assumed Premiums Earned	6,095,400	5,936,200	5,834,000
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 5,533,300	$ 5,356,300	$ 5,249,600
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	110.20%	110.80%	111.10%
US Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 4,700	$ 4,300	$ 1,600
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0	0	40,200
Assumed Premiums Earned	22,500	19,400	63,000
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 27,200	$ 23,700	$ 24,400
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	82.70%	81.90%	258.20%
Canada Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0	$ 0	$ 0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	46,900	38,100	36,500
Assumed Premiums Earned	1,070,900	940,100	965,100
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,024,000	$ 902,000	$ 928,600
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	104.60%	104.20%	103.90%
Canada Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0	$ 0	$ 0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0	0	0
Assumed Premiums Earned	43,400	38,200	38,700
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 43,400	$ 38,200	$ 38,700
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%
EMEA Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 26,000	$ 26,600	$ 24,100
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	25,900	34,900	30,900
Assumed Premiums Earned	1,423,100	1,310,000	1,146,900
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 1,423,200	$ 1,301,700	$ 1,140,100
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.60%	100.60%
EMEA Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 200	$ 200	$ 300
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	143,700	125,000	84,400
Assumed Premiums Earned	338,800	288,500	264,400
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 195,300	$ 163,700	$ 180,300
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	173.50%	176.20%	146.60%
Asia Pacific Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0	$ 0	$ 0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	49,800	54,500	50,300
Assumed Premiums Earned	2,346,200	2,107,500	1,731,800
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 2,296,400	$ 2,053,000	$ 1,681,500
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	102.20%	102.70%	103.00%
Asia Pacific Non-Traditional Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0	$ 0	$ 0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0	0	0
Assumed Premiums Earned	900	2,400	5,400
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 900	$ 2,400	$ 5,400
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%
Corporate And Other Segment Reporting Information [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Earned	$ 0	$ 0	$ 0
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	0	0	0
Assumed Premiums Earned	100	100	300
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	$ 100	$ 100	$ 300
Reinsurance Premiums for Insurance Companies, by Product Segment, Percentage of Amount Assumed to Net	100.00%	100.00%	100.00%

Valuation and Qualifying Acco_3

Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning Balance	$ 226.9	$ 133.4	$ 127.1
Valuation Allowances and Reserves, Charged to Cost and Expense	(33.7)	(88.5)	(11)
Valuation Allowances and Reserves, Charged to Other Accounts	12.1	10.6	4.7
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	0	5.6	0
Valuation Allowances and Reserves, Balance, Ending Balance	181.1	226.9	133.4
SEC Schedule, 12-09, Allowance, Loan and Lease Loss, Real Estate [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Balance, Beginning Balance	9.4	7.7	6.8
Valuation Allowances and Reserves, Charged to Cost and Expense	(1.9)	(1.7)	(0.9)
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	0	0	0
Valuation Allowances and Reserves, Balance, Ending Balance	$ 11.3	$ 9.4	$ 7.7