Aflac (AFL) 10-Q 26 Apr 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 17, 2019
Document Type	10-Q
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	AFL
Entity Registrant Name	Aflac Incorporated
Entity Central Index Key	0000004977
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		745,469,119

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Net premiums, principally supplemental health insurance	$ 4,691	$ 4,745
Net investment income	878	837
Realized investment gains (losses):
Other-than-temporary impairment losses realized	(2)	(7)
Other gains (losses)	73	(127)
Total realized investment gains (losses)	71	(134)
Other income (loss)	17	16
Total revenues	5,657	5,464
Benefits and expenses:
Benefits and claims, net	2,967	3,042
Acquisition and operating expenses:
Amortization of deferred policy acquisition costs	340	314
Insurance commissions	331	337
Insurance and other expenses	719	733
Interest expense	58	56
Total acquisition and operating expenses	1,448	1,440
Total benefits and expenses	4,415	4,482
Earnings before income taxes	1,242	982
Income taxes	314	265
Net earnings	$ 928	$ 717
Net earnings per share:
Basic (in dollars per share)	$ 1.23	$ 0.92
Diluted (in dollars per share)	$ 1.23	$ 0.91
Weighted-average outstanding common shares used in computing earnings per share (In thousands):
Basic (in shares)	751,423	778,550
Diluted (in shares)	755,790	783,852
Cash dividends per share	$ 0.27	$ 0.26

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net earnings	$ 928	$ 717
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period	(1)	824
Unrealized gains (losses) on fixed maturity securities:
Unrealized holding gains (losses) on fixed maturity securities during period	3,196	(1,931)
Reclassification adjustment for realized (gains) losses on fixed maturity securities included in net earnings	(17)	(2)
Unrealized gains (losses) on derivatives during period	(3)	6
Pension liability adjustment during period	7	(3)
Total other comprehensive income (loss) before income taxes	3,182	(1,106)
Income tax expense (benefit) related to items of other comprehensive income (loss)	852	(763)
Other comprehensive income (loss), net of income taxes	2,330	(343)
Total comprehensive income (loss)	$ 3,258	$ 374

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Investments and Cash:
Available for sale, fixed maturity securities		$ 87,924	$ 82,895
Held to maturity, fixed maturity securities		30,163	30,318
Equity securities		1,041	987
Commercial mortgage and other loans		7,180	6,919
Other investments		1,238	787
Cash and cash equivalents		3,892	4,337
Total investments and cash		131,438	126,243
Receivables		858	851
Accrued investment income		728	773
Deferred policy acquisition costs		9,892	9,875
Property and equipment, at cost less accumulated depreciation	[1]	559	443
Other		2,204	2,221
Total assets		145,679	140,406
Policy Liabilities:
Future policy benefits		87,011	86,368
Unpaid policy claims		4,625	4,584
Unearned premiums		4,859	5,090
Other policyholders’ funds		7,185	7,146
Total policy liabilities		103,680	103,188
Income taxes		5,182	4,020
Payables for return of cash collateral on loaned securities		1,969	1,052
Notes payable and lease obligations	[1]	5,900	5,778
Other		2,899	2,906
Total liabilities		119,630	116,944
Commitments and contingent liabilities (Note 12)
Shareholders’ equity:
Common stock of $.10 par value. In thousands: authorized 1,900,000 shares in 2019 and 2018; issued 1,348,600 shares in 2019 and 1,347,540 shares in 2018		135	135
Additional paid-in capital		2,208	2,177
Retained earnings		32,513	31,788
Accumulated other comprehensive income (loss):
Unrealized foreign currency translation gains (losses)		(1,848)	(1,847)
Unrealized gain (losses) on fixed maturity securities		6,561	4,234
Unrealized gains (losses) on derivatives		(26)	(24)
Pension liability adjustment		(206)	(212)
Treasury stock, at average cost		(13,288)	(12,789)
Total shareholders’ equity		26,049	23,462
Total liabilities and shareholders’ equity		145,679	140,406
Consolidated Entity Excluding Variable Interest Entities (VIE)
Investments and Cash:
Available for sale, fixed maturity securities		83,381	78,429
Variable Interest Entity, Consolidated
Investments and Cash:
Available for sale, fixed maturity securities		4,543	4,466
Equity securities		180	160
Commercial mortgage and other loans		5,892	5,528
Other investments	[2]	374	328
Policy Liabilities:
Total liabilities		$ 108	$ 102
[1]	See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2019 related to leases.
[2]	Consists entirely of alternative investments in limited partnerships

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Available for sale, fixed maturity securities, amortized cost		$ 78,706	$ 76,856
Held to maturity, fixed maturity securities, fair value		37,446	36,722
Commercial mortgage and other loans		7,180	6,919
Other investments		$ 1,238	$ 787
Common stock, par value (in dollars per share)		$ 0.10	$ 0.10
Common stock, shares authorized (in shares)		1,900,000	1,900,000
Common stock, shares issued (in shares)		1,348,600	1,347,540
Variable Interest Entity, Consolidated
Available for sale, fixed maturity securities, amortized cost		$ 3,756	$ 3,849
Commercial mortgage and other loans		5,892	5,528
Other investments	[1]	374	328
Consolidated Entity Excluding Variable Interest Entities (VIE)
Available for sale, fixed maturity securities, amortized cost		$ 74,950	$ 73,007
[1]	Consists entirely of alternative investments in limited partnerships

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions		Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle, net of income taxes	[1]	$ 0	$ 0	$ 0	$ (226)	$ 226	$ 0
Balance, beginning of period at Dec. 31, 2017		24,598	135	2,052	29,895	4,028	(11,512)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		717	0	0	717	0	0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		447	0	0	0	447	0
Unrealized gains (losses) on fixed maturity securities during period, net of income taxes and reclassification adjustments	[1]	(984)	0	0	0	(984)	0
Unrealized gains (losses) on derivatives during period, net of income taxes		2	0	0	0	2	0
Pension liability adjustment during period, net of income taxes		(34)	0	0	0	(34)	0
Dividends to shareholders		(203)	0	0	(203)	0	0
Exercise of stock options		14	0	14	0	0	0
Share-based compensation		10	0	10	0	0	0
Purchases of treasury stock		(309)	0	0	0	0	(309)
Treasury stock reissued		29	0	13	0	0	16
Balance, end of period at Mar. 31, 2018		24,287	135	2,089	30,183	3,685	(11,805)
Balance, beginning of period at Dec. 31, 2018		23,462	135	2,177	31,788	2,151	(12,789)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		928	0	0	928	0	0
Unrealized foreign currency translation gains (losses) during period, net of income taxes		(1)	0	0	0	(1)	0
Unrealized gains (losses) on fixed maturity securities during period, net of income taxes and reclassification adjustments		2,327	0	0	0	2,327	0
Unrealized gains (losses) on derivatives during period, net of income taxes		(2)	0	0	0	(2)	0
Pension liability adjustment during period, net of income taxes		6	0	0	0	6	0
Dividends to shareholders		(203)	0	0	(203)	0	0
Exercise of stock options		11	0	11	0	0	0
Share-based compensation		8	0	8	0	0	0
Purchases of treasury stock		(517)	0	0	0	0	(517)
Treasury stock reissued		30	0	12	0	0	18
Balance, end of period at Mar. 31, 2019		$ 26,049	$ 135	$ 2,208	$ 32,513	$ 4,481	$ (13,288)
[1]	See Note 1 of the Notes to the Consolidated Financial Statements in the Company's 2018 Annual Report on Form 10-K

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Retained earnings
Dividends to shareholders (in dollars per share)	$ 0.27	$ 0.26

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net earnings	$ 928	$ 717
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in receivables and advance premiums	35	14
Capitalization of deferred policy acquisition costs	(357)	(349)
Amortization of deferred policy acquisition costs	340	314
Increase in policy liabilities	468	572
Change in income tax liabilities	316	(131)
Realized investment (gains) losses	(71)	134
Other, net	(115)	(33)
Net cash provided (used) by operating activities	1,544	1,238
Proceeds from investments sold or matured:
Available-for-sale fixed maturity securities	760	943
Equity securities	153	157
Held-to-maturity fixed maturity securities	155	50
Commercial mortgage and other loans	493	146
Costs of investments acquired:
Available for sale fixed maturity securities	(2,548)	(3,975)
Equity securities	(151)	(166)
Commercial mortgage and other loans	(669)	(1,772)
Other investments, net	(442)	(125)
Settlement of derivatives, net	(3)	(1)
Cash received (pledged or returned) as collateral, net	976	4,578
Other, net	(15)	(34)
Net cash provided (used) by investing activities	(1,291)	(199)
Cash flows from financing activities:
Purchases of treasury stock	(490)	(296)
Proceeds from borrowings	0	2
Dividends paid to shareholders	(195)	(195)
Change in investment-type contracts, net	(13)	7
Treasury stock reissued	12	14
Other, net	0	(5)
Net cash provided (used) by financing activities	(686)	(473)
Effect of exchange rate changes on cash and cash equivalents	(12)	23
Net change in cash and cash equivalents	(445)	589
Cash and cash equivalents, beginning of period	4,337	3,491
Cash and cash equivalents, end of period	3,892	4,080
Supplemental disclosures of cash flow information:
Income taxes paid	(2)	396
Interest paid	36	36
Noncash interest	22	21
Impairment losses included in realized investment losses	2	7
Noncash financing activities:
Lease obligations	1	1
Associate stock bonus
Treasury stock issued for:
Treasury stock issued	6	5
Shareholder dividend reinvestment
Treasury stock issued for:
Treasury stock issued	8	8
Share-based compensation grants
Treasury stock issued for:
Treasury stock issued	$ 4	$ 2

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Description of Business Aflac Incorporated (the Parent Company) and its subsidiaries (collectively, the Company) primarily sell supplemental health and life insurance in the United States and Japan. The Company's insurance business is marketed and administered through American Family Life Assurance Company of Columbus (Aflac) in the United States and, effective April 1, 2018, through Aflac Life Insurance Japan Ltd. (ALIJ) in Japan. Prior to April 1, 2018, the Company's insurance business was marketed in Japan as a branch of Aflac. The Company’s operations consist of two reportable business segments: Aflac U.S., which includes Aflac, and Aflac Japan, which includes ALIJ. American Family Life Assurance Company of New York (Aflac New York) is a wholly owned subsidiary of Aflac. Most of Aflac's policies are individually underwritten and marketed through independent agents. Additionally, Aflac U.S. markets and administers group products through Continental American Insurance Company (CAIC), branded as Aflac Group Insurance. The Company's insurance operations in the United States and Japan service the two markets for the Company's insurance business. Aflac Japan's revenues, including realized gains and losses on its investment portfolio, accounted for 68% and 71% of the Company's total revenues in the three -month periods ended March 31, 2019 and 2018 , respectively. The percentage of the Company's total assets attributable to Aflac Japan was 84% at March 31, 2019 and December 31, 2018 , respectively. Basis of Presentation The Company prepares its financial statements in accordance with U.S. generally accepted accounting principles (U.S. GAAP). These principles are established primarily by the Financial Accounting Standards Board (FASB). In these Notes to the Consolidated Financial Statements, references to U.S. GAAP issued by the FASB are derived from the FASB Accounting Standards Codification TM (ASC). The preparation of financial statements in conformity with U.S. GAAP requires the Company to make estimates based on currently available information when recording transactions resulting from business operations. The most significant items on the Company's balance sheet that involve a greater degree of accounting estimates and actuarial determinations subject to changes in the future are the valuation of investments and derivatives, deferred policy acquisition costs (DAC), liabilities for future policy benefits and unpaid policy claims, and income taxes. These accounting estimates and actuarial determinations are sensitive to market conditions, investment yields, mortality, morbidity, commission and other acquisition expenses, and terminations by policyholders. As additional information becomes available, or actual amounts are determinable, the recorded estimates will be revised and reflected in operating results. Although some variability is inherent in these estimates, the Company believes the amounts provided are adequate. The unaudited consolidated financial statements include the accounts of the Parent Company, its subsidiaries and those entities required to be consolidated under applicable accounting standards. All material intercompany accounts and transactions have been eliminated. In the opinion of management, the accompanying unaudited consolidated financial statements of the Company contain all adjustments, consisting of normal recurring accruals, which are necessary to fairly present the consolidated balance sheets as of March 31, 2019 , and December 31, 2018 , the consolidated statements of earnings and comprehensive income (loss), shareholders' equity and cash flows for the three -month periods ended March 31, 2019 and 2018 . Results of operations for interim periods are not necessarily indicative of results for the entire year. As a result, these financial statements should be read in conjunction with the financial statements and notes thereto included in the Company's annual report on Form 10-K for the year ended December 31, 2018 ( 2018 Annual Report). Reclassifications : Certain reclassifications have been made to prior-year amounts to conform to current-year reporting classifications. These reclassifications had no impact on net earnings or total shareholders' equity. New Accounting Pronouncements Recently Adopted Accounting Pronouncements Standard Description Date of Adoption Effect on Financial Statements or Other Significant Matters Accounting Standard Update (ASU) 2018-15 Intangibles - Goodwill and Other - Internal-Use Software, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract In August 2018, the FASB issued amendments to align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. Early adopted as of January 1, 2019 The adoption of this guidance did not have a significant impact on the Company’s financial position, results of operations or disclosures Standard Description Date of Adoption Effect on Financial Statements or Other Significant Matters ASU 2016-02 Leases as clarified and amended by: ASU 2018-01, Leases: Land Easement Practical Expedient for Transition to Topic 842, ASU 2018-10 , Codification Improvements to Topic 842, Leases, ASU 2018-11 , Leases, Targeted Improvements, and ASU 2018-20 , Leases: Narrow-Scope Improvements for Lessors In February 2016, the FASB issued updated guidance for accounting for leases (“Leases Update”). Per the Leases Update, lessees are required to recognize all leases on the balance sheet with the exception of short-term leases. A lease liability will be recorded for the obligation of a lessee to make lease payments arising from a lease. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The Leases Update provided a number of optional practical expedients. The Company elected the "package of practical expedients," which permits the Company not to reassess under the new standard its prior conclusions about lease identification, lease classification and initial direct costs. Under the Leases Update, lessor accounting is largely unchanged. In January 2018, an amendment was issued to the Leases Update which provided an entity with the option to elect a transition practical expedient to not evaluate land easements that exist or expired before the entity's adoption of the Leases Update and that were not previously accounted for as leases. In July 2018, the FASB issued two amendments to the Leases Update which clarified, corrected errors in, or made minor improvements to the Leases Update and provided entities with an optional transition method to adopt the Leases Update by recording a cumulative-effect adjustment to beginning retained earnings. Additionally, the amendments provided lessors with a practical expedient to not separate nonlease components from associated lease components and instead account for those components as a single component under certain conditions. In December 2018, an amendment to the Leases Update was issued to clarify: 1) lessor accounting for all sales (and other similar) taxes; 2) the handling of certain lessor costs when the amount of those costs is not readily determinable; and 3) lessor allocation of certain variable payments to the lease and non-lease components. January 1, 2019 The Company has operating and finance leases for office space and equipment. The Company elected the short-term lease exemption for all classes of leases which allows the Company to not recognize right-of-use assets and lease liabilities on the consolidated balance sheet and allows the Company to recognize the lease expense for short-term leases on a straight-line basis over the lease term. The Company elected the practical expedient to not separate lease and non-lease components and applied it to all classes of leases where the non-lease components are not significant. Some of the Company's leases include options to extend or terminate the lease and the lease terms may include such options when it is reasonably certain that the Company will exercise that option. Certain leases also include options to purchase the leased property. The leases within scope of the Leases Update increased the Company's right-of-use assets and lease liabilities recorded in its consolidated balance sheet by $134 million. As of January 1, 2019, the Company did not have land easements, but has elected the practical expedient as a safe harbor. The Company elected the optional transition method and as a safe harbor, the practical expedient provided to lessors. The Company has made an accounting policy election to exclude amounts collected from customers for all sales (and other similar) taxes from the transaction price. The adoption of the Leases Update and related amendments did not have a significant impact on the Company's financial position, results of operations, or disclosures. Accounting Pronouncements Pending Adoption Standard Description Effect on Financial Statements or Other Significant Matters ASU 2018-17 Consolidation: Targeted Improvements to Related Party Guidance for Variable Interest Entities In October 2018, the FASB issued targeted improvements which provide that indirect interests held through related parties under common control should be considered on a proportional basis for determining whether fees paid to decision makers and service providers are variable interests. The amendments are effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on the Company’s financial position, results of operations or disclosures. ASU 2018-14 Compensation - Retirement Benefits - Defined Benefit Plans - General, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans In August 2018, the FASB issued amendments to modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. Accordingly, six disclosures requirements were removed, two added and two clarified. The amendments are effective for public business entities for fiscal years beginning after December 15, 2020. Early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on the Company’s financial position, results of operations, or disclosures. ASU 2018-13 Fair Value Measurement, Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement In August 2018, the FASB issued amendments to the disclosure requirements on fair value measurements. The amendments remove, modify, and add certain disclosures. The amendments are effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. Further, an entity is permitted to early adopt any removed or modified disclosures upon issuance of this update and delay adoption of the additional disclosures until their effective date. The adoption of this guidance is not expected to have a significant impact on the Company’s financial position, results of operations, or disclosures. ASU 2018-12 Financial Services - Insurance, Targeted Improvements to the Accounting for Long-Duration Contracts In August 2018, the FASB issued amendments that will significantly change how insurers account for long-duration contracts. The amendments will change existing recognition, measurement, presentation, and disclosure requirements. Issues addressed in the new guidance include: 1) a requirement to review and, if there is a change, update assumptions for the liability for future policy benefits at least annually, and to update the discount rate assumption quarterly, 2) accounting for market risk benefits at fair value, 3) simplified amortization for deferred acquisition costs, and 4) enhanced financial statement presentation and disclosures. The amendments are effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early application of the amendments is permitted. The Company is thoroughly evaluating the impact of adoption and expects that the adoption will have a significant impact on the Company’s financial position, results of operations, and disclosures. The Company anticipates that the requirement to update assumptions for liability for future policy benefits will have a significant impact on its results of operations, systems, processes and controls while the requirement to update the discount rate will have a significant impact on its equity. The Company has no products with market risk benefits. The Company does not expect to early adopt the updated standard. ASU 2017-04 Intangibles - Goodwill and Other: Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued amendments simplifying the subsequent measurement of goodwill. An entity, under this update, is no longer required to perform a hypothetical purchase price allocation to measure goodwill impairment. Instead, the entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The amendments are effective for public business entities that are SEC filers for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for any goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Standard Description Effect on Financial Statements or Other Significant Matters ASU 2016-13 Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued amendments that require a financial asset (or a group of financial assets) measured on an amortized cost basis to be presented net of an allowance for credit losses in order to reflect the amount expected to be collected on the financial asset(s). The measurement of expected credit losses is amended by replacing the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform about a credit loss. Credit losses on available-for-sale debt securities will continue to be measured in a manner similar to current U.S. GAAP; however, the amendments require that credit losses be presented as an allowance rather than as a write-down. Other amendments include changes to the balance sheet presentation and interest income recognition of purchased financial assets with a more-than-insignificant amount of credit deterioration since origination (PCD financial assets). The amendments are effective for public companies for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Companies may early adopt this guidance as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The amendments will be adopted following a modified-retrospective approach resulting in a cumulative effect adjustment in retained earnings as of the beginning of the year of adoption. Two exceptions to this adoption method are for PCD financial assets and debt securities for which other-than-temporary impairment (OTTI) will have been recognized before the effective date. Loans purchased with credit deterioration accounted for under current U.S. GAAP as "purchased credit impaired" (PCI) financial assets will be classified as PCD financial assets at transition and PCD guidance will be applied prospectively. Debt securities that have experienced OTTI before the effective date will follow a prospective adoption method which allows an entity to maintain the same amortized cost basis before and after the effective date. The Company has identified certain financial instruments in scope of this guidance to include certain fixed maturity securities, loans and loan receivables and reinsurance recoverables (See Notes 3 and 7 for current balances of instruments in scope). The Company is continuing its progress towards updating its credit loss projection models and accounting systems in order to comply with the required changes in measurement of credit losses. The Company currently expects loans and loan receivables and held-to-maturity fixed maturity securities to be the asset classes most significantly impacted upon adoption of the guidance. The Company continues to evaluate the impact of adoption of this guidance on its financial position, results of operations, and disclosures. Recent accounting guidance not discussed above is not applicable, did not have, or is not expected to have a material impact to the Company's business. For additional information on new accounting pronouncements and recent accounting guidance and their impact, if any, on the Company's financial position or results of operations, see Note 1 of the Notes to the Consolidated Financial Statements in the 2018

BUSINESS SEGMENT INFORMATION

BUSINESS SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
BUSINESS SEGMENT INFORMATION	BUSINESS SEGMENT INFORMATION The Company consists of two reportable insurance business segments: Aflac Japan and Aflac U.S., both of which sell supplemental health and life insurance. In addition, operating business units that are not individually reportable and business activities, including reinsurance retrocession activities, not included in Aflac Japan or Aflac U.S. are included in Corporate and other. The Company does not allocate corporate overhead expenses to business segments. Consistent with U.S. GAAP accounting guidance for segment reporting, the Company evaluates and manages its business segments using a financial performance measure called pretax adjusted earnings. Adjusted earnings are adjusted revenues less benefits and adjusted expenses. The adjustments to both revenues and expenses account for certain items that cannot be predicted or that are outside management’s control. Adjusted revenues are U.S. GAAP total revenues excluding realized investment gains and losses, except for amortized hedge costs/income related to foreign currency exposure management strategies and net interest cash flows from derivatives associated with certain investment strategies. Adjusted expenses are U.S. GAAP total acquisition and operating expenses including the impact of interest cash flows from derivatives associated with notes payable but excluding any nonrecurring or other items not associated with the normal course of the Company’s insurance operations and that do not reflect Aflac’s underlying business performance. The Company excludes income taxes related to operations to arrive at pretax adjusted earnings. Information regarding operations by reportable segment and Corporate and other, follows: Three Months Ended (In millions) 2019 2018 Revenues: Aflac Japan: Net earned premiums $ 3,180 $ 3,263 Net investment income, less amortized hedge costs 610 588 Other income 12 12 Total Aflac Japan 3,802 3,863 Aflac U.S.: Net earned premiums 1,461 1,427 Net investment income 177 175 Other income 2 2 Total Aflac U.S. 1,640 1,604 Corporate and other 95 79 Total adjusted revenues 5,537 5,546 Realized investment gains (losses) (1),(2),(3) 120 (82 ) Total revenues $ 5,657 $ 5,464 (1) Amortized hedge costs of $62 and $55 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency exposure management strategies have been reclassified from realized investment gains (losses) and reported as a deduction from net investment income when analyzing operations. (2) Amortized hedge income of $20 and $2 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency exposure management strategies has been reclassified from realized investment gains (losses) and reported as an increase to net investment income when analyzing operations. (3) Net interest cash flows from derivatives associated with certain investment strategies of $(7) for the three -month period ended March 31, 2019 and an immaterial amount in 2018, respectively, have been reclassified from realized investment gains (losses) and included in adjusted earnings as a component of net investment income. Three Months Ended (In millions) 2019 2018 Pretax earnings: Aflac Japan $ 834 $ 818 Aflac U.S. 323 337 Corporate and other (18 ) (46 ) Pretax adjusted earnings 1,139 1,109 Realized investment gains (losses) (1),(2),(3),(4) 103 (98 ) Other income (loss) 0 (29 ) Total earnings before income taxes $ 1,242 $ 982 Income taxes applicable to pretax adjusted earnings $ 291 $ 289 Effect of foreign currency translation on after-tax (8 ) 21 (1) Amortized hedge costs of $62 and $55 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency management strategies have been reclassified from realized investment gains (losses) and reported as a deduction from pretax adjusted earnings when analyzing operations. (2) Amortized hedge income of $20 and $2 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency management strategies has been reclassified from realized investment gains (losses) and reported as an increase in pretax adjusted earnings when analyzing operations. (3) Net interest cash flows from derivatives associated with certain investment strategies of $(7) for the three -month period ended March 31, 2019 and an immaterial amount in 2018, respectively, have been reclassified from realized investment gains (losses) and included in adjusted earnings as a component of net investment income. (4) A gain of $17 and $17 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable have been reclassified from realized investment gains (losses) and included in adjusted earnings when analyzing operations Assets were as follows: (In millions) March 31, December 31, Assets: Aflac Japan $ 123,042 $ 118,342 Aflac U.S. 19,965 19,100 Corporate and other 2,672 2,964 Total assets $ 145,679 $ 140,406

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2019
Investments [Abstract]
INVESTMENTS	INVESTMENTS Investment Holdings The amortized cost for the Company's investments in fixed maturity securities, the cost for equity securities and the fair values of these investments are shown in the following tables. March 31, 2019 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value Fixed maturity securities: Yen-denominated: Japan government and agencies $ 31,238 $ 4,813 $ 2 $ 36,049 Municipalities 509 93 3 599 Mortgage- and asset-backed securities 233 27 0 260 Public utilities 1,822 344 0 2,166 Sovereign and supranational 740 65 0 805 Banks/financial institutions 5,664 597 139 6,122 Other corporate 5,043 824 20 5,847 Total yen-denominated 45,249 6,763 164 51,848 U.S. dollar-denominated: U.S. government and agencies 190 11 1 200 Municipalities 1,204 105 0 1,309 Mortgage- and asset-backed securities 147 7 0 154 Public utilities 3,841 522 32 4,331 Sovereign and supranational 276 73 0 349 Banks/financial institutions 2,798 484 13 3,269 Other corporate 25,001 2,061 598 26,464 Total U.S. dollar-denominated 33,457 3,263 644 36,076 Total securities available for sale $ 78,706 $ 10,026 $ 808 $ 87,924 December 31, 2018 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value through other comprehensive income: Fixed maturity securities: Yen-denominated: Japan government and agencies $ 30,637 $ 3,700 $ 140 $ 34,197 Municipalities 385 32 9 408 Mortgage- and asset-backed securities 155 22 0 177 Public utilities 1,732 280 4 2,008 Sovereign and supranational 826 123 0 949 Banks/financial institutions 5,440 502 238 5,704 Other corporate 4,852 649 44 5,457 Total yen-denominated 44,027 5,308 435 48,900 U.S dollar-denominated: U.S. government and agencies 137 9 1 145 Municipalities 1,343 120 8 1,455 Mortgage- and asset-backed securities 155 8 1 162 Public utilities 4,772 496 105 5,163 Sovereign and supranational 251 60 0 311 Banks/financial institutions 2,860 389 35 3,214 Other corporate 23,311 1,343 1,109 23,545 Total U.S. dollar-denominated 32,829 2,425 1,259 33,995 Total securities available for sale $ 76,856 $ 7,733 $ 1,694 $ 82,895 March 31, 2019 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturity securities: Yen-denominated: Japan government and agencies $ 21,961 $ 6,018 $ 0 $ 27,979 Municipalities 814 247 0 1,061 Mortgage- and asset-backed securities 20 1 0 21 Public utilities 2,728 340 0 3,068 Sovereign and supranational 1,154 178 0 1,332 Banks/financial institutions 949 100 10 1,039 Other corporate 2,537 414 5 2,946 Total yen-denominated 30,163 7,298 15 37,446 Total securities held to maturity $ 30,163 $ 7,298 $ 15 $ 37,446 December 31, 2018 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturity securities: Yen-denominated: Japan government and agencies $ 21,712 $ 5,326 $ 0 $ 27,038 Municipalities 359 110 0 469 Mortgage- and asset-backed securities 14 1 0 15 Public utilities 2,727 254 8 2,973 Sovereign and supranational 1,551 289 0 1,840 Banks/financial institutions 1,445 158 20 1,583 Other corporate 2,510 332 38 2,804 Total yen-denominated 30,318 6,470 66 36,722 Total securities held to maturity $ 30,318 $ 6,470 $ 66 $ 36,722 March 31, 2019 December 31, 2018 (In millions) Fair Value Fair Value Equity securities, carried at fair value through net earnings: Equity securities: Yen-denominated $ 662 $ 641 U.S. dollar-denominated 379 346 Total equity securities $ 1,041 $ 987 The methods of determining the fair values of the Company's investments in fixed maturity securities and equity securities are described in Note 5. During the first quarter of 2019 and 2018, respectively, the Company did not reclassify any investments from the held-to-maturity category to the available-for-sale category. Contractual and Economic Maturities The contractual and economic maturities of the Company's investments in fixed maturity securities at March 31, 2019 , were as follows: (In millions) Amortized Fair Available for sale: Due in one year or less $ 889 $ 950 Due after one year through five years 8,483 8,624 Due after five years through 10 years 10,111 11,034 Due after 10 years 58,843 66,902 Mortgage- and asset-backed securities 380 414 Total fixed maturity securities available for sale $ 78,706 $ 87,924 Held to maturity: Due in one year or less $ 135 $ 137 Due after one year through five years 1,112 1,187 Due after five years through 10 years 678 739 Due after 10 years 28,218 35,362 Mortgage- and asset-backed securities 20 21 Total fixed maturity securities held to maturity $ 30,163 $ 37,446 Economic maturities are the expected maturity date created by the combination of features in the financial instrument. Expected maturities may differ from contractual maturities because some issuers have the right to call or prepay obligations with or without call or prepayment penalties. Investment Concentrations The Company's process for investing in credit-related investments begins with an independent approach to underwriting each issuer's fundamental credit quality. The Company evaluates independently those factors that it believes could influence an issuer's ability to make payments under the contractual terms of the Company's instruments. This includes a thorough analysis of a variety of items including the issuer's country of domicile (including political, legal, and financial considerations); the industry in which the issuer competes (with an analysis of industry structure, end-market dynamics, and regulation); company specific issues (such as management, assets, earnings, cash generation, and capital needs); and contractual provisions of the instrument (such as financial covenants and position in the capital structure). The Company further evaluates the investment considering broad business and portfolio management objectives, including asset/liability needs, portfolio diversification, and expected income. Investment exposures that individually exceeded 10% of shareholders' equity were as follows: March 31, 2019 December 31, 2018 (In millions) Credit Amortized Fair Credit Amortized Fair Japan National Government (1) A+ $51,775 $62,275 A+ $51,207 $59,945 (1) Japan Government Bonds (JGBs) or JGB-backed securities Realized Investment Gains and Losses Information regarding pretax realized gains and losses from investments is as follows: Three Months Ended (In millions) 2019 2018 Realized investment gains (losses): Fixed maturity securities: Available for sale: Gross gains from sales $ 12 $ 10 Gross losses from sales (8 ) (2 ) Foreign currency gains (losses) on sales and redemptions 13 (5 ) Total fixed maturity securities 17 3 Equity securities 58 (46 ) Loan receivables: Loan loss reserves (2 ) (7 ) Total loan receivables (2 ) (7 ) Derivatives and other: Derivative gains (losses) 0 144 Foreign currency gains (losses) (2 ) (228 ) Total derivatives and other (2 ) (84 ) Total realized investment gains (losses) $ 71 $ (134 ) The unrealized holding gains , net of losses , recorded as a component of realized investment gains and losses for the three -month period ended March 31, 2019 , that relates to equity securities still held at the March 31, 2019 , reporting date was $47 million . Unrealized Investment Gains and Losses Effect on Shareholders’ Equity The net effect on shareholders’ equity of unrealized gains and losses from fixed maturity securities was as follows: (In millions) March 31, 2019 December 31, Unrealized gains (losses) on securities available for sale $ 9,218 $ 6,039 Deferred income taxes (2,657 ) (1,805 ) Shareholders’ equity, unrealized gains (losses) on fixed maturity securities $ 6,561 $ 4,234 Gross Unrealized Loss Aging The following tables show the fair values and gross unrealized losses of the Company's available-for-sale and held-to-maturity investments that were in an unrealized loss position, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position. March 31, 2019 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. government and U.S. dollar-denominated $ 65 $ 1 $ 65 $ 1 $ 0 $ 0 Japan government and Yen-denominated 139 2 139 2 0 0 Municipalities: Yen-denominated 70 3 70 3 0 0 Mortgage- and asset- U.S. dollar-denominated 53 0 53 0 0 0 Public utilities: U.S. dollar-denominated 808 32 306 14 502 18 Banks/financial institutions: U.S. dollar-denominated 345 13 209 10 136 3 Yen-denominated 2,229 149 2,229 149 0 0 Other corporate: U.S. dollar-denominated 9,182 598 3,149 213 6,033 385 Yen-denominated 525 25 525 25 0 0 Total $ 13,416 $ 823 $ 6,745 $ 417 $ 6,671 $ 406 December 31, 2018 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. government and U.S. dollar-denominated $ 67 $ 1 $ 67 $ 1 $ 0 $ 0 Japan government and Yen-denominated 3,604 140 3,604 140 0 0 Municipalities: U.S. dollar-denominated 515 8 515 8 0 0 Yen-denominated 148 9 148 9 0 0 Mortgage- and asset- U.S. dollar-denominated 74 1 74 1 0 0 Public utilities: U.S. dollar-denominated 1,585 105 892 48 693 57 Yen-denominated 604 12 604 12 0 0 Banks/financial institutions: U.S. dollar-denominated 625 35 340 19 285 16 Yen-denominated 3,057 258 3,057 258 0 0 Other corporate: U.S. dollar-denominated 12,899 1,109 5,782 407 7,117 702 Yen-denominated 1,306 82 1,306 82 0 0 Total $ 24,484 $ 1,760 $ 16,389 $ 985 $ 8,095 $ 775 Analysis of Securities in Unrealized Loss Positions The unrealized losses on the Company's fixed maturity securities investments have been primarily related to general market changes in interest rates, foreign exchange rates, and/or the levels of credit spreads rather than specific concerns with the issuer's ability to pay interest and repay principal. For any significant declines in fair value of its fixed maturity securities, the Company performs a more focused review of the related issuers' credit profile. For corporate issuers, the Company evaluates their assets, business profile including industry dynamics and competitive positioning, financial statements and other available financial data. For non-corporate issuers, the Company analyzes all sources of credit support, including issuer-specific factors. The Company utilizes information available in the public domain and, for certain private placement issuers, from consultations with the issuers directly. The Company also considers ratings from Nationally Recognized Statistical Rating Organizations (NRSROs), as well as the specific characteristics of the security it owns including seniority in the issuer's capital structure, covenant protections, or other relevant features. From these reviews, the Company evaluates the issuers' continued ability to service the Company's investment through payment of interest and principal. Assuming no credit-related factors develop, unrealized gains and losses on fixed maturity securities are expected to diminish as investments near maturity. Based on its credit analysis, the Company believes that the issuers of its fixed maturity investments in the sectors shown in the table above have the ability to service their obligations to the Company. Commercial Mortgage and Other Loans The Company classifies its transitional real estate loans (TREs), commercial mortgage loans (CMLs) and middle market loans (MMLs) as held-for-investment and includes them in the commercial mortgage and other loans line on the consolidated balance sheets. The Company carries them on the balance sheet at amortized cost less an estimated allowance for loan losses. The following table reflects the composition of commercial mortgage and other loans by portfolio segment as of the periods presented. (In millions) March 31, 2019 December 31, 2018 Commercial mortgage and other loans: Transitional real estate loans $ 4,398 $ 4,394 Commercial mortgage loans 1,085 1,065 Middle market loans 1,726 1,487 Total gross commercial mortgage and other loans 7,209 6,946 Valuation allowance (29 ) (27 ) Total net commercial mortgage and other loans $ 7,180 $ 6,919 Commercial mortgage and transitional real estate loans were secured by properties entirely within the United States. Middle market loans are issued only to companies domiciled within the United States. Transitional Real Estate Loans Transitional real estate loans are commercial mortgage loans that are typically relatively short-term floating rate instruments secured by a first lien on the property. These loans provide funding for properties undergoing a change in their physical characteristics and/or economic profile and do not typically require any principal repayment prior to the maturity date. This loan portfolio has guidelines that limit the average loan-to-value at origination to be 70% or lower with individual loan-to-value limits at origination of 80% or less. As of March 31, 2019 , the Company had $733 million in outstanding commitments to fund transitional real estate loans. These commitments are contingent on the final underwriting and due diligence to be performed. Commercial Mortgage Loans Commercial mortgage loans are typically fixed rate loans on commercial real estate with partial repayment of principal over the life of the loan with the remaining outstanding principal being repaid upon maturity. This loan portfolio has guidelines that limit the average loan-to-value at origination to be 65% or lower with individual loan-to-value limits at origination of 70% or less. As of March 31, 2019 , the Company had $28 million in outstanding commitments to fund commercial mortgage loans. These commitments are contingent on the final underwriting and due diligence to be performed. Middle Market Loans Middle market loans are typically first lien senior secured cash flow loans to small to mid-size companies for working capital, refinancing, acquisition, and recapitalization. These loans are generally considered to be below investment grade. The carrying value for middle market loans included an unfunded amount of $127 million and $56 million , as of March 31, 2019 , and December 31, 2018 , respectively, that is reflected in other liabilities on the consolidated balance sheets. As of March 31, 2019 , the Company had commitments of approximately $677 million to fund potential future loan originations related to this investment program. These commitments are contingent upon the availability of middle market loans that meet the Company's underwriting criteria. Allowance for Loan Losses The Company's allowance for loan losses is established using both general and specific allowances. The general allowance is used for loans grouped by similar risk characteristics where a loan-specific or market-specific risk has not been identified, but for which the Company estimates probable incurred losses. The specific allowance is used on an individual loan basis when it is probable that a loss has been incurred. There was no specific loan loss reserve as of March 31, 2019 , and December 31, 2018 . As of March 31, 2019 , and December 31, 2018 , the Company's general allowance for loan losses was $29 million and $27 million , respectively. The following table presents the rollforward of the allowance for loan losses by portfolio segment during the three -month period ended March 31 . (In millions) Commercial Mortgage Loans Transitional Real Estate Loans Middle Market Loans Total Allowance for loan losses at December 31, 2018 $ (1 ) $ (17 ) $ (9 ) $ (27 ) Addition to (release of) allowance for credit losses 0 (1 ) (1 ) (2 ) Allowance for loan losses at March 31, 2019 $ (1 ) $ (18 ) $ (10 ) $ (29 ) The key credit quality indicators used by the company in establishing the general and specific loan loss reserves, as well as in determining whether or not a loan should be impaired, include loan-to-value and debt service coverage ratios for CMLs and TREs and ratings for our middle market loan portfolio. Given that transitional real estate loans involve properties undergoing renovation or construction, loan-to-value provides the most insight on the credit risk of the property. The performance of the loans are monitored and reviewed periodically, but not less than quarterly. As of March 31, 2019 , and December 31, 2018 , the Company had no loans that were past due in regards to principal and/or interest payments. Additionally, the Company held no loans that were on nonaccrual status or considered impaired as of March 31, 2019 , and December 31, 2018 . The Company had no troubled debt restructurings during the three months ended March 31, 2019 and 2018. Other Investments The table below reflects the composition of the carrying value for other investments as of the periods presented. (In millions) March 31, 2019 December 31, 2018 Other investments: Policy loans $ 236 $ 232 Short-term investments (1) 543 152 Limited partnerships 434 377 Other 25 26 Total other investments $ 1,238 $ 787 (1) Includes securities lending collateral As of March 31, 2019 , the Company had $915 million in outstanding commitments to fund alternative investments in limited partnerships. Variable Interest Entities (VIEs) As a condition of its involvement or investment in a VIE, the Company enters into certain protective rights and covenants that preclude changes in the structure of the VIE that would alter the creditworthiness of the Company's investment or its beneficial interest in the VIE. For those VIEs other than certain unit trust structures, the Company's involvement is passive in nature. The Company has not, nor has it been, required to purchase any securities issued in the future by these VIEs. The Company's ownership interest in VIEs is limited to holding the obligations issued by them. The Company has no direct or contingent obligations to fund the limited activities of these VIEs, nor does it have any direct or indirect financial guarantees related to the limited activities of these VIEs. The Company has not provided any assistance or any other type of financing support to any of the VIEs it invests in, nor does it have any intention to do so in the future. For those VIEs in which the Company holds debt obligations, the weighted-average lives of the Company's notes are very similar to the underlying collateral held by these VIEs where applicable. The Company's risk of loss related to its interests in any of its VIEs is limited to the carrying value of the related investments held in the VIE. VIEs - Consolidated The following table presents the cost or amortized cost, fair value and balance sheet caption in which the assets and liabilities of consolidated VIEs are reported. Investments in Consolidated Variable Interest Entities March 31, 2019 December 31, 2018 (In millions) Cost or Amortized Fair Cost or Amortized Fair Assets: Fixed maturity securities, available for sale $ 3,756 $ 4,543 $ 3,849 $ 4,466 Equity securities 180 180 160 160 Commercial mortgage and other loans 5,892 5,894 5,528 5,506 Other investments (1) 374 374 328 328 Other assets (2) 178 178 182 182 Total assets of consolidated VIEs $ 10,380 $ 11,169 $ 10,047 $ 10,642 Liabilities: Other liabilities (2) $ 108 $ 108 $ 102 $ 102 Total liabilities of consolidated VIEs $ 108 $ 108 $ 102 $ 102 (1) Consists entirely of alternative investments in limited partnerships (2) Consists entirely of derivatives The Company is substantively the only investor in the consolidated VIEs listed in the table above. As the sole investor in these VIEs, the Company has the power to direct the activities of a variable interest entity that most significantly impact the entity's economic performance and is therefore considered to be the primary beneficiary of the VIEs that it consolidates. The Company also participates in substantially all of the variability created by these VIEs. The activities of these VIEs are limited to holding invested assets and foreign currency swaps, as appropriate, and utilizing the cash flows from these securities to service its investment. Neither the Company nor any of its creditors are able to obtain the underlying collateral of the VIEs unless there is an event of default or other specified event. For those VIEs that contain a swap, the Company is not a direct counterparty to the swap contracts and has no control over them. The Company's loss exposure to these VIEs is limited to its original investment. The Company's consolidated VIEs do not rely on outside or ongoing sources of funding to support their activities beyond the underlying collateral and swap contracts, if applicable. With the exception of its investment in unit trust structures, the underlying collateral assets and funding of the Company's consolidated VIEs are generally static in nature. Investments in Unit Trust Structures The Company also utilizes unit trust structures in its Aflac Japan segment to invest in various asset classes. As the sole investor of these VIEs, the Company is required to consolidate these trusts under U.S. GAAP. VIEs - Not Consolidated The table below reflects the amortized cost, fair value and balance sheet caption in which the Company's investment in VIEs not consolidated are reported. Investments in Variable Interest Entities Not Consolidated March 31, 2019 December 31, 2018 (In millions) Amortized Fair Amortized Fair Assets: Fixed maturity securities, available for sale $ 4,455 $ 5,025 $ 4,575 $ 4,982 Fixed maturity securities, held to maturity 2,006 2,331 2,007 2,254 Other investments (1) 59 59 49 49 Total investments in VIEs not consolidated $ 6,520 $ 7,415 $ 6,631 $ 7,285 (1) Consists entirely of alternative investments in limited partnerships The Company holds alternative investments in limited partnerships that have been determined to be VIEs. These partnerships invest in private equity and structured investments. The Company’s maximum exposure to loss on these investments is limited to the amount of its investment. The Company is not the primary beneficiary of these VIEs and is therefore not required to consolidate them. The Company classifies these investments as Other investments in the consolidated balance sheets. Certain investments in VIEs that the Company is not required to consolidate are investments that are in the form of debt obligations from the VIEs that are irrevocably and unconditionally guaranteed by their corporate parents or sponsors. These VIEs are the primary financing vehicles used by their corporate sponsors to raise financing in the capital markets. The variable interests created by these VIEs are principally or solely a result of the debt instruments issued by them. The Company does not have the power to direct the activities that most significantly impact the entity's economic performance, nor does it have the obligation to absorb losses of the entity or the right to receive benefits from the entity. As such, the Company is not the primary beneficiary of these VIEs and is therefore not required to consolidate them. Securities Lending and Pledged Securities The Company lends fixed maturity and public equity securities to financial institutions in short-term security-lending transactions. These short-term security-lending arrangements increase investment income with minimal risk. The Company receives cash or other securities as collateral for such loans. The Company's security lending policy requires that the fair value of the securities received as collateral be 102% or more of the fair value of the loaned securities and that unrestricted cash received as collateral be 100% or more of the fair value of the loaned securities. The securities loaned continue to be carried as investment assets on the Company's balance sheet during the terms of the loans and are not reported as sales. For loans involving unrestricted cash or securities as collateral, the collateral is reported as an asset with a corresponding liability for the return of the collateral. For loans where the Company receives as collateral securities that the Company is not permitted to sell or repledge, the collateral is not reflected on the consolidated financial statements. Details of collateral by loaned security type and remaining maturity of the agreements were as follows: Securities Lending Transactions Accounted for as Secured Borrowings March 31, 2019 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Greater Total Securities lending transactions: Fixed maturity securities: Japan government and agencies $ 0 $ 1,101 $ 1,901 $ 3,002 Public utilities 15 0 0 15 Banks/financial institutions 74 0 0 74 Other corporate 764 0 0 764 Equity securities 15 0 0 15 Total borrowings $ 868 $ 1,101 $ 1,901 $ 3,870 Gross amount of recognized liabilities for securities lending transactions $ 1,969 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 1,901 (1) The related loaned security, under the Company's U.S. securities lending program, can be returned to the Company at the transferee's discretion; therefore, they are classified as Overnight and Continuous. Securities Lending Transactions Accounted for as Secured Borrowings December 31, 2018 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Greater Total Securities lending transactions: Fixed maturity securities: Japan government and agencies $ 0 $ 387 $ 1,190 $ 1,577 Municipalities 5 0 0 5 Public utilities 27 0 0 27 Banks/financial institutions 74 0 0 74 Other corporate 549 0 0 549 Equity securities 10 0 0 10 Total borrowings $ 665 $ 387 $ 1,190 $ 2,242 Gross amount of recognized liabilities for securities lending transactions $ 1,052 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 1,190 (1) The related loaned security, under the Company's U.S. securities lending program, can be returned to the Company at the transferee's discretion; therefore, they are classified as Overnight and Continuous The Company did not have any repurchase agreements or repurchase-to-maturity transactions outstanding as of March 31, 2019 , and December 31, 2018 , respectively.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS The Company's freestanding derivative financial instruments have historically consisted of: • foreign currency forwards and options used in hedging foreign exchange risk on U.S. dollar-denominated investments in Aflac Japan's portfolio • foreign currency forwards and options used to economically hedge certain portions of forecasted cash flows denominated in yen and hedge the Company's long term exposure to a weakening yen • cross-currency interest rate swaps, also referred to as foreign currency swaps, associated with certain senior notes and subordinated debentures • foreign currency swaps and, in prior periods, credit default swaps that are associated with investments in special-purpose entities, including VIEs where the Company is the primary beneficiary • interest rate swaps used to economically hedge interest rate fluctuations in certain variable-rate investments • interest rate swaptions used to hedge changes in the fair value associated with interest rate fluctuations for certain U.S. dollar-denominated available-for-sale fixed-maturity securities. Some of the Company's derivatives are designated as cash flow hedges, fair value hedges or net investment hedges; however, other derivatives do not qualify for hedge accounting or the Company elects not to designate them as accounting hedges. Derivative Types Foreign currency forwards and options are executed for the Aflac Japan segment in order to hedge the currency risk on the carrying value of certain U.S. dollar-denominated investments. The average maturity of these forwards and options can change depending on factors such as market conditions and types of investments being held. In situations where the maturity of the forwards and options is shorter than the underlying investment being hedged, the Company may enter into new forwards and options near maturity of the existing derivative in order to continue hedging the underlying investment. In forward transactions, Aflac Japan agrees with another party to buy a fixed amount of yen and sell a corresponding amount of U.S. dollars at a specified future date. Aflac Japan also executes foreign currency option transactions in a collar strategy, where Aflac Japan agrees with another party to simultaneously purchase put options and sell call options. In the purchased put transactions, Aflac Japan obtains the option to buy a fixed amount of yen and sell a corresponding amount of U.S. dollars at a specified future date. In the sold call transaction, Aflac Japan agrees to sell a fixed amount of yen and buy a corresponding amount of U.S. dollars at a specified future date. The combination of purchasing the put option and selling the call option results in no net premium being paid (i.e. a costless or zero-cost collar). The foreign currency forwards and options are used in fair value hedging relationships to mitigate the foreign exchange risk associated with U.S. dollar-denominated investments supporting yen-denominated liabilities. Prior to April 1, 2018, foreign currency forwards and options (through a collar strategy, as discussed above) were used to hedge the currency risk associated with the net investment in Aflac Japan. In these forward transactions, Aflac agreed with another party to buy a fixed amount of U.S. dollars and sell a corresponding amount of yen at a specified price at a specified future date. In the option transactions, the Company used a combination of foreign currency options to protect expected future cash flows by simultaneously purchasing yen put options (options that protect against a weakening yen) and selling yen call options (options that limit participation in a strengthening yen). The combination of these two actions created a zero-cost collar. The Company enters into foreign currency swaps pursuant to which it exchanges an initial principal amount in one currency for an initial principal amount of another currency, with an agreement to re-exchange the principal amounts at a future date. There may also be periodic exchanges of payments at specified intervals based on the agreed upon rates and notional amounts. Foreign currency swaps are used primarily in the consolidated VIEs in the Company's Aflac Japan portfolio to convert foreign-denominated cash flows to yen, the functional currency of Aflac Japan, in order to minimize cash flow fluctuations. The Company also uses foreign currency swaps to economically convert certain of its U.S. dollar-denominated senior note and subordinated debenture principal and interest obligations into yen-denominated obligations. In order to reduce investment income volatility from its variable-rate investments, the Company enters into receive–fixed, pay–floating interest rate swaps. These derivatives are cleared and settled through a central clearinghouse. Swaptions are used to mitigate the adverse impact resulting from significant changes in the fair value of U.S. dollar-denominated available-for-sale securities due to fluctuation in interest rates. In a payer swaption, the Company pays a premium to obtain the right, but not the obligation, to enter into a swap contract where it will pay a fixed rate and receive a floating rate. Interest rate swaption collars are combinations of two swaption positions. In order to maximize the efficiency of the collars while minimizing cost, a collar strategy is used whereby the Company purchases a long payer swaption (the Company purchases an option that allows it to enter into a swap where the Company will pay the fixed rate and receive the floating rate of the swap) and sells a short receiver swaption (the Company sells an option that provides the counterparty with the right to enter into a swap where the Company will receive the fixed rate and pay the floating rate of the swap). The combination of purchasing the long payer swaption and selling the short receiver swaption results in no net premium being paid (i.e. a costless or zero-cost collar). Derivative Balance Sheet Classification The table below summarizes the balance sheet classification of the Company's derivative fair value amounts, as well as the gross asset and liability fair value amounts. The fair value amounts presented do not include income accruals. Derivative assets are included in “Other Assets,” while derivative liabilities are included in “Other Liabilities” within the Company’s Consolidated Balance Sheets. The notional amount of derivative contracts represents the basis upon which pay or receive amounts are calculated and are not reflective of exposure or credit risk. March 31, 2019 December 31, 2018 (In millions) Asset Liability Asset Liability Hedge Designation/ Derivative Notional Fair Value Fair Value Notional Fair Value Fair Value Cash flow hedges: Foreign currency swaps - VIE $ 75 $ 0 $ 6 $ 75 $ 1 $ 4 Total cash flow hedges 75 0 6 75 1 4 Fair value hedges: Foreign currency forwards 691 0 24 2,086 0 34 Foreign currency options 10,887 0 2 9,070 3 1 Interest rate swaptions 1,500 0 1 500 0 1 Total fair value hedges 13,079 0 27 11,656 3 36 Non-qualifying strategies: Foreign currency swaps 2,800 96 98 2,800 103 129 Foreign currency swaps - VIE 2,587 178 102 2,587 181 101 Foreign currency forwards 15,208 119 132 16,057 126 117 Foreign currency options 552 0 0 430 0 0 Interest rate swaps 4,750 8 0 4,750 3 0 Total non-qualifying strategies 25,897 401 332 26,624 413 347 Total derivatives $ 39,051 $ 401 $ 365 $ 38,355 $ 417 $ 387 Cash Flow Hedges For certain variable-rate U.S. dollar-denominated available-for-sale securities held by Aflac Japan via consolidated VIEs, foreign currency swaps are used to swap the USD variable rate interest and principal payments to fixed rate JPY interest and principal payments. The Company has designated foreign currency swaps as a hedge of the variability in cash flows of a forecasted transaction or of amounts to be received or paid related to a recognized asset (“cash flow” hedge). The remaining maximum length of time for which these cash flows are hedged is eight years. The derivatives in the Company's consolidated VIEs that are not designated as accounting hedges are discussed in the "non-qualifying strategies" section of this note. Fair Value Hedges The Company designates and accounts for certain foreign currency forwards, options, and interest rate swaptions as fair value hedges when they meet the requirements for hedge accounting. The Company recognizes gains and losses on these derivatives as well as the offsetting gain or loss on the related hedged items in current earnings. Foreign currency forwards and options hedge the foreign currency exposure of certain U.S. dollar-denominated available-for-sale fixed-maturity investments held in Aflac Japan. The change in the fair value of the foreign currency forwards related to the changes in the difference between the spot rate and the forward price is excluded from the assessment of hedge effectiveness. The change in fair value of the foreign currency option related to the time value of the option is recognized in current earnings and is excluded from the assessment of hedge effectiveness. Interest rate swaptions hedge the interest rate exposure of certain U.S. dollar-denominated available-for-sale securities held in Aflac Japan. For these hedging relationships, the Company excludes time value from the assessment of hedge effectiveness and recognizes changes in the intrinsic value of the swaptions in current earnings within net investment income. The change in the time value of the swaptions is recognized in other comprehensive income (loss) and amortized into earnings (net investment income) over its legal term. The following table presents the gains and losses on derivatives and the related hedged items in fair value hedges. Fair Value Hedging Relationships (In millions) Hedging Derivatives Hedged Items Hedging Derivatives Hedged Items Total Gains (Losses) (1) Gains (Losses) (2) Gains (Losses) (2) Net Realized Gains (Losses) Recognized for Fair Value Hedge Three Months Ended March 31, 2019: Foreign currency Fixed maturity securities $ 9 $ (10 ) $ 19 $ (18 ) $ 1 Foreign currency Fixed maturity securities (4 ) (4 ) 0 0 0 Interest rate Fixed maturity securities (1 ) (1 ) 0 0 0 Total gains (losses) $ 4 $ (15 ) $ 19 $ (18 ) $ 1 Three Months Ended March 31, 2018: Foreign currency forwards Fixed maturity securities $ 414 $ (39 ) $ 453 $ (464 ) $ (11 ) Foreign currency options Fixed maturity securities (1 ) (1 ) 0 0 0 Total gains (losses) $ 413 $ (40 ) $ 453 $ (464 ) $ (11 ) (1) Gains (losses) excluded from effectiveness testing includes the forward point on foreign currency forwards and time value change on foreign currency options which are reported in the consolidated statement of earnings as realized investment gains (losses). It also includes the change in the fair value of the interest rate swaptions related to the time value of the swaptions which is recognized as a component of other comprehensive income (loss). (2) Gains and losses on foreign currency forwards and options and related hedged items are reported in the consolidated statement of earnings as realized investment gains (losses). For interest rate swaptions and related hedged items, gains and losses included in the hedge assessment are reported within net investment income. For the three -month period ended March 31, 2019 , those gains and losses on interest rate swaptions and related hedged items were immaterial. The following table shows the carrying amounts of assets designated and qualifying as hedged items in fair value hedges of interest rate risk and the related cumulative hedge adjustment included in the carrying amount. (In millions) Carrying Amount of the Hedged Assets/(Liabilities) (1) Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of Hedged Assets/(Liabilities) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Fixed maturity securities $ 5,285 $ 6,593 $ 276 $ 294 (1) The balance includes hedging adjustment on discontinued hedging relationships of $276 in 2019 and $294 in 2018. The total notional amount of the Company's interest rate swaptions was $1,500 in 2019 and $500 in 2018. The hedging adjustment related to these derivatives was immaterial. Net Investment Hedge The Company's investment in Aflac Japan is affected by changes in the yen/dollar exchange rate. To mitigate this exposure, the Parent Company's yen-denominated liabilities (see Note 8) have been designated as non-derivative hedges and, prior to April 1, 2018, foreign currency forwards and options have been designated as derivative hedges of the foreign currency exposure of the Company's net investment in Aflac Japan. The Company's net investment hedge was effective during the three -month periods ended March 31, 2019 and 2018 , respectively. Non-qualifying Strategies For the Company's derivative instruments in consolidated VIEs that do not qualify for hedge accounting treatment, all changes in their fair value are reported in current period earnings within realized investment gains (losses). The amount of gain or loss recognized in earnings for the Company's VIEs is attributable to the derivatives in those investment structures. While the change in value of the swaps is recorded through current period earnings, the change in value of the available-for-sale fixed maturity securities associated with these swaps is recorded through other comprehensive income. As of March 31, 2019 , the Parent Company had cross-currency interest rate swap agreements related to its $350 million senior notes due February 2022, $700 million senior notes due June 2023, $750 million senior notes due November 2024 and $450 million senior notes due March 2025. Changes in the values of these swaps are recorded through current period earnings. For additional information regarding these swaps, see Note 9 of the Notes to the Consolidated Financial Statements in the 2018 Annual Report. The Company uses foreign exchange forwards and options to economically mitigate the currency risk of some of its U.S. dollar-denominated loan receivables held within the Aflac Japan segment. These arrangements are not designated as accounting hedges, as the foreign currency remeasurement of the loan receivables impacts current period earnings, and generally offsets gains and losses from foreign exchange forwards within realized investment gains (losses). The Company also has certain foreign exchange forwards on U.S. dollar-denominated AFS securities where hedge accounting is not being applied. In order to economically mitigate currency risk of future yen dividends from Aflac Japan while lowering consolidated hedge costs associated with Aflac Japan's U.S. dollar investment hedging, the Parent Company entered into offsetting hedge positions using foreign exchange forwards. This activity is reported in the Corporate and other segment. The Company uses interest rate swaps to economically convert the variable rate investment income to a fixed rate on certain variable-rate investments. Impact of Derivatives and Hedging Instruments The following table summarizes the impact to realized investment gains (losses) and other comprehensive income (loss) from all derivatives and hedging instruments. Three Months Ended March 31, 2019 2018 (In millions) Net Investment Income Loss (1) Realized Investment Other (2) Net Investment Income Loss (1) Realized Investment Other (2) Qualifying hedges: Cash flow hedges: Foreign currency swaps - VIE $ (1 ) $ 0 $ (2 ) $ 0 $ 1 $ 6 Total cash flow hedges (1 ) 0 (3 ) (2 ) 0 1 (3 ) 6 Fair value hedges: Foreign currency forwards (4) (9 ) (50 ) Foreign currency options (4) (4 ) (1 ) Interest rate swaptions (4) 0 0 (1 ) 0 0 0 Total fair value hedges 0 (13 ) (1 ) 0 (51 ) 0 Net investment hedge: Non-derivative hedging instruments 0 0 0 (84 ) Foreign currency options 0 0 0 (8 ) Total net investment hedge 0 0 0 (92 ) Non-qualifying strategies: Foreign currency swaps 44 (110 ) Foreign currency swaps - VIE (16 ) 124 Foreign currency forwards (21 ) 179 Foreign currency options 0 1 Interest rate swaps 6 0 Total non-qualifying strategies 13 194 Total $ (1 ) $ 0 $ (3 ) $ 0 $ 144 $ (86 ) (1) Net investment income (loss) includes net interest on swaps. (2) Cash flow hedge items and the change in the fair value of interest rate swaptions related to the time value of the swaptions in fair value hedges are recorded as unrealized gains (losses) on derivatives and net investment hedge items are recorded in the unrealized foreign currency translation gains (losses) line in the consolidated statement of comprehensive income (loss). (3) Impact of cash flow hedges reported as realized investment gains (losses) includes an immaterial amount of gains or losses reclassified from accumulated other comprehensive income (loss) into earnings. It also includes an immaterial amount excluded from effectiveness testing during the three-month periods ended March 31, 2019 and 2018 , respectively. (4) Impact shown net of effect of hedged items (see Fair Value Hedges section of this Note 4 for further detail) The impact on earnings from derivatives in cash flow hedge relationships includes a loss of an immaterial amount during the three-month periods ended March 31, 2019 and 2018 , respectively, resulting from reclassifications from accumulated other comprehensive income (loss) to net investment income. As of March 31, 2019 , deferred gains and losses on derivative instruments recorded in accumulated other comprehensive income that are expected to be reclassified to earnings during the next twelve months were immaterial. Credit Risk Assumed through Derivatives For the foreign currency and credit default swaps associated with the Company's VIE investments for which it is the primary beneficiary, the Company bears the risk of loss due to counterparty default even though it is not a direct counterparty to those contracts. The Company is a direct counterparty to the foreign currency swaps that it has entered into in connection with certain of its senior notes and subordinated debentures; foreign currency forwards; and foreign currency options, and therefore the Company is exposed to credit risk in the event of nonperformance by the counterparties in those contracts. The risk of counterparty default for the Company's foreign currency swaps, certain foreign currency forwards, and foreign currency options is mitigated by collateral posting requirements that counterparties to those transactions must meet. As of March 31, 2019 , there were 16 counterparties to the Company's derivative agreements, with four comprising 65% of the aggregate notional amount. As of March 31, 2019, all counterparties were investment grade. The Company engages in over-the-counter (OTC) bilateral derivative transactions directly with unaffiliated third parties under International Swaps and Derivatives Association, Inc. (ISDA) agreements and other documentation. Most of the ISDA agreements also include Credit Support Annexes (CSAs) provisions, which generally provide for two-way collateral postings at the first dollar of exposure. The Company mitigates the risk that counterparties to transactions might be unable to fulfill their contractual obligations by monitoring counterparty credit exposure and collateral value while generally requiring that collateral be posted at the outset of the transaction. In addition, a significant portion of the derivative transactions have provisions that give the counterparty the right to terminate the transaction upon a downgrade of Aflac’s financial strength rating. The actual amount of payments that the Company could be required to make depends on market conditions, the fair value of outstanding affected transactions, and other factors prevailing at and after the time of the downgrade. The Company also engages in OTC cleared derivative transactions through regulated central clearing counterparties. These positions are marked to market and margined on a daily basis (both initial margin and variation margin), and the Company has minimal exposure to credit-related losses in the event of nonperformance by counterparties to these derivatives. Collateral posted by the Company to third parties for derivative transactions can generally be repledged or resold by the counterparties. The aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a net liability position by counterparty was approximately $133 million and $139 million as of March 31, 2019 , and December 31, 2018 , respectively. If the credit-risk-related contingent features underlying these agreements had been triggered on March 31, 2019 , the Company estimates that it would be required to post a maximum of $23 million of additional collateral to these derivative counterparties. The Company is generally allowed to sell or repledge collateral obtained from its derivative counterparties, although it does not typically exercise such rights. (See the Offsetting tables below for collateral posted or received as of the reported balance sheet dates.) Offsetting of Financial Instruments and Derivatives Most of the Company's derivative instruments are subject to enforceable master netting arrangements that provide for the net settlement of all derivative contracts between the Parent Company or its subsidiaries and the respective counterparty in the event of default or upon the occurrence of certain termination events. Collateral support agreements with the master netting arrangements generally provide that the Company will receive or pledge financial collateral at the first dollar of exposure. The Company has securities lending agreements with unaffiliated financial institutions that post collateral to the Company in return for the use of its fixed maturity and public equity securities (see Note 3). When the Company has entered into securities lending agreements with the same counterparty, the agreements generally provide for net settlement in the event of default by the counterparty. This right of set-off allows the Company to keep and apply collateral received if the counterparty failed to return the securities borrowed from the Company as contractually agreed. The tables below summarize the Company's derivatives and securities lending transactions, and as reflected in the tables, in accordance with U.S. GAAP, the Company's policy is to not offset these financial instruments in the Consolidated Balance Sheets. Offsetting of Financial Assets and Derivative Asset March 31, 2019 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Assets Gross Amount Offset in Balance Sheet Net Amount of Assets Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Received Net Amount Derivative assets: Derivative assets subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 215 $ 0 $ 215 $ (118 ) $ (10 ) $ (80 ) $ 7 OTC - cleared 8 0 8 0 0 (1 ) 7 Total derivative assets subject to a master netting agreement or offsetting arrangement 223 0 223 (118 ) (10 ) (81 ) 14 Derivative assets not subject to a master netting agreement or offsetting arrangement OTC - bilateral 178 178 178 Total derivative assets not subject to a master netting agreement or offsetting arrangement 178 178 178 Total derivative assets 401 0 401 (118 ) (10 ) (81 ) 192 Securities lending and similar arrangements 1,959 0 1,959 0 0 (1,959 ) 0 Total $ 2,360 $ 0 $ 2,360 $ (118 ) $ (10 ) $ (2,040 ) $ 192 December 31, 2018 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Assets Gross Amount Offset in Balance Sheet Net Amount of Assets Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Received Net Amount Derivative assets: Derivative assets subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 231 $ 0 $ 231 $ (152 ) $ (23 ) $ (55 ) $ 1 OTC - cleared 3 0 3 0 0 (3 ) 0 Total derivative assets subject to a master netting agreement or offsetting arrangement 234 0 234 (152 ) (23 ) (58 ) 1 Derivative assets not subject to a master netting agreement or offsetting arrangement OTC - bilateral 183 183 183 Total derivative assets not subject to a master netting agreement or offsetting arrangement 183 183 183 Total derivative assets 417 0 417 (152 ) (23 ) (58 ) 184 Securities lending and similar arrangements 1,029 0 1,029 0 0 (1,029 ) 0 Total $ 1,446 $ 0 $ 1,446 $ (152 ) $ (23 ) $ (1,087 ) $ 184 Offsetting of Financial Liabilities and Derivative Liabilities March 31, 2019 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Liabilities Gross Amount Offset in Balance Sheet Net Amount of Liabilities Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Pledged Net Amount Derivative liabilities: Derivative liabilities subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 257 $ 0 $ 257 $ (118 ) $ (65 ) $ (45 ) $ 29 Total derivative liabilities subject to a master netting agreement or offsetting arrangement 257 0 257 (118 ) (65 ) (45 ) 29 Derivative liabilities not subject to a master netting agreement or offsetting arrangement OTC - bilateral 108 108 108 Total derivative liabilities not subject to a master netting agreement or offsetting arrangement 108 108 108 Total derivative liabilities 365 0 365 (118 ) (65 ) (45 ) 137 Securities lending and similar arrangements 1,969 0 1,969 (1,959 ) 0 0 10 Total $ 2,334 $ 0 $ 2,334 $ (2,077 ) $ (65 ) $ (45 ) $ 147 December 31, 2018 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Liabilities Gross Amount Offset in Balance Sheet Net Amount of Liabilities Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Pledged Net Amount Derivative liabilities: Derivative liabilities subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 285 $ 0 $ 285 $ (152 ) $ (37 ) $ (68 ) $ 28 Total derivative liabilities subject to a master netting agreement or offsetting arrangement 285 0 285 (152 ) (37 ) (68 ) 28 Derivative liabilities not subject to a master netting agreement or offsetting arrangement OTC - bilateral 102 102 102 Total derivative liabilities not subject to a master netting agreement or offsetting arrangement 102 102 102 Total derivative liabilities 387 0 387 (152 ) (37 ) (68 ) 130 Securities lending and similar arrangements 1,052 0 1,052 (1,029 ) 0 0 23 Total $ 1,439 $ 0 $ 1,439 $ (1,181 ) $ (37 ) $ (68 ) $ 153 For additional information on the Company's financial instruments, see the accompanying Notes 1, 3 and 5 and Notes 1, 3 and 5 of the Notes to the Consolidated Financial Statements in the 2018

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair Value Hierarchy U.S. GAAP specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. These two types of inputs create three valuation hierarchy levels. Level 1 valuations reflect quoted market prices for identical assets or liabilities in active markets. Level 2 valuations reflect quoted market prices for similar assets or liabilities in an active market, quoted market prices for identical or similar assets or liabilities in non-active markets or model-derived valuations in which all significant valuation inputs are observable in active markets. Level 3 valuations reflect valuations in which one or more of the significant inputs are not observable in an active market. The following tables present the fair value hierarchy levels of the Company's assets and liabilities that are measured and carried at fair value on a recurring basis. March 31, 2019 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturity securities: Government and agencies $ 34,727 $ 1,522 $ 0 $ 36,249 Municipalities 0 1,908 0 1,908 Mortgage- and asset-backed securities 0 236 178 414 Public utilities 0 6,412 85 6,497 Sovereign and supranational 0 1,154 0 1,154 Banks/financial institutions 0 9,368 23 9,391 Other corporate 0 32,027 284 32,311 Total fixed maturity securities 34,727 52,627 570 87,924 Equity securities 925 70 46 1,041 Other investments 543 0 0 543 Cash and cash equivalents 3,892 0 0 3,892 Other assets: Foreign currency swaps 0 96 178 274 Foreign currency forwards 0 119 0 119 Interest rate swaps 0 8 0 8 Total other assets 0 223 178 401 Total assets $ 40,087 $ 52,920 $ 794 $ 93,801 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 98 $ 108 $ 206 Foreign currency forwards 0 156 0 156 Foreign currency options 0 2 0 2 Interest rate swaptions 0 1 0 1 Total liabilities $ 0 $ 257 $ 108 $ 365 December 31, 2018 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturity securities: Government and agencies $ 32,993 $ 1,349 $ 0 $ 34,342 Municipalities 0 1,863 0 1,863 Mortgage- and asset-backed securities 0 162 177 339 Public utilities 0 7,062 109 7,171 Sovereign and supranational 0 1,260 0 1,260 Banks/financial institutions 0 8,895 23 8,918 Other corporate 0 28,789 213 29,002 Total fixed maturity securities 32,993 49,380 522 82,895 Equity securities 874 67 46 987 Other investments 152 0 0 152 Cash and cash equivalents 4,337 0 0 4,337 Other assets: Foreign currency swaps 0 103 182 285 Foreign currency forwards 0 126 0 126 Foreign currency options 0 3 0 3 Interest rate swaps 0 3 0 3 Total other assets 0 235 182 417 Total assets $ 38,356 $ 49,682 $ 750 $ 88,788 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 132 $ 102 $ 234 Foreign currency forwards 0 151 0 151 Foreign currency options 0 1 0 1 Interest rate swaptions 0 1 0 1 Total liabilities $ 0 $ 285 $ 102 $ 387 The following tables present the carrying amount and fair value categorized by fair value hierarchy level for the Company's financial instruments that are not carried at fair value. March 31, 2019 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturity securities: Government and agencies $ 21,961 $ 27,629 $ 350 $ 0 $ 27,979 Municipalities 814 0 1,061 0 1,061 Mortgage and asset-backed 20 0 8 13 21 Public utilities 2,728 0 3,068 0 3,068 Sovereign and 1,154 0 1,332 0 1,332 Banks/financial institutions 949 0 1,039 0 1,039 Other corporate 2,537 0 2,946 0 2,946 Commercial mortgage and 7,180 0 0 7,185 7,185 Other investments (1) 25 0 25 0 25 Total assets $ 37,368 $ 27,629 $ 9,829 $ 7,198 $ 44,656 Liabilities: Other policyholders’ funds $ 7,185 $ 0 $ 0 $ 7,110 $ 7,110 Notes payable 5,766 0 5,809 270 6,079 Total liabilities $ 12,951 $ 0 $ 5,809 $ 7,380 $ 13,189 (1) Excludes policy loans of $236 and equity method investments of $434 , at carrying value December 31, 2018 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturity securities: Government and agencies $ 21,712 $ 27,030 $ 8 $ 0 $ 27,038 Municipalities 359 0 469 0 469 Mortgage and asset-backed 14 0 0 15 15 Public utilities 2,727 0 2,973 0 2,973 Sovereign and 1,551 0 1,840 0 1,840 Banks/financial institutions 1,445 0 1,583 0 1,583 Other corporate 2,510 0 2,804 0 2,804 Commercial mortgage and 6,919 0 0 6,893 6,893 Other investments (1) 26 0 26 0 26 Total assets $ 37,263 $ 27,030 $ 9,703 $ 6,908 $ 43,641 Liabilities: Other policyholders’ funds $ 7,146 $ 0 $ 0 $ 7,067 $ 7,067 Notes payable 5,765 0 5,606 270 5,876 Total liabilities $ 12,911 $ 0 $ 5,606 $ 7,337 $ 12,943 (1) Excludes policy loans of $232 and equity method investments of $377 , at carrying value Fair Value of Financial Instruments Fixed maturity and equity securities The Company determines the fair values of fixed maturity securities and public and privately-issued equity securities using the following approaches or techniques: price quotes and valuations from third party pricing vendors (including quoted market prices readily available from public exchange markets) and non-binding price quotes the Company obtains from outside brokers. A third party pricing vendor has developed valuation models to determine fair values of privately issued securities to reflect the impact of the persistent economic environment and the changing regulatory framework. These models are discounted cash flow (DCF) valuation models, but also use information from related markets, specifically the CDS market to estimate expected cash flows. These models take into consideration any unique characteristics of the securities and make various adjustments to arrive at an appropriate issuer-specific loss adjusted credit curve. This credit curve is then used with the relevant recovery rates to estimate expected cash flows and modeling of additional features, including illiquidity adjustments, if necessary, to price the security by discounting those loss adjusted cash flows. In cases where a credit curve cannot be developed from the specific security features, the valuation methodology takes into consideration other market observable inputs, including: 1) the most appropriate comparable security(ies) of the issuer; 2) issuer-specific CDS spreads; 3) bonds or CDS spreads of comparable issuers with similar characteristics such as rating, geography, or sector; or 4) bond indices that are comparative in rating, industry, maturity and region. The pricing data and market quotes the Company obtains from outside sources, including third party pricing services, are reviewed internally for reasonableness. If a fair value appears unreasonable, the Company will re-examine the inputs and assess the reasonableness of the pricing data with the vendor. Additionally, the Company may compare the inputs to relevant market indices and other performance measurements. Based on management's analysis, the valuation is confirmed or may be revised if there is evidence of a more appropriate estimate of fair value based on available market data. The Company has performed verification of the inputs and calculations in any valuation models to confirm that the valuations represent reasonable estimates of fair value. The fixed maturity securities classified as Level 3 consist of securities with limited or no observable valuation inputs. For Level 3 securities, the Company estimates the fair value of these securities by obtaining non-binding broker quotes from a limited number of brokers. These brokers base their quotes on a combination of their knowledge of the current pricing environment and market conditions. The Company considers these inputs to be unobservable. The Company also considers a variety of significant valuation inputs in the valuation process, including forward exchange rates, yen swap rates, dollar swap rates, interest rate volatilities, credit spread data on specific issuers, assumed default and default recovery rates, and certain probability assumptions. In obtaining these valuation inputs, the Company has determined that certain pricing assumptions and data used by its pricing sources are difficult to validate or corroborate by the market and/or appear to be internally developed rather than observed in or corroborated by the market. The use of these unobservable valuation inputs causes more subjectivity in the valuation process for these securities. For the periods presented, the Company has not adjusted the quotes or prices it obtains from the pricing services and brokers it uses. The following tables present the pricing sources for the fair values of the Company's fixed maturity and equity securities. March 31, 2019 (In millions) Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Total Securities available for sale, carried at fair value: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 34,727 $ 1,522 $ 0 $ 36,249 Total government and agencies 34,727 1,522 0 36,249 Municipalities: Third party pricing vendor 0 1,908 0 1,908 Total municipalities 0 1,908 0 1,908 Mortgage- and asset-backed securities: Third party pricing vendor 0 236 0 236 Broker/other 0 0 178 178 Total mortgage- and asset-backed securities 0 236 178 414 Public utilities: Third party pricing vendor 0 6,412 0 6,412 Broker/other 0 0 85 85 Total public utilities 0 6,412 85 6,497 Sovereign and supranational: Third party pricing vendor 0 1,154 0 1,154 Total sovereign and supranational 0 1,154 0 1,154 Banks/financial institutions: Third party pricing vendor 0 9,323 0 9,323 Broker/other 0 45 23 68 Total banks/financial institutions 0 9,368 23 9,391 Other corporate: Third party pricing vendor 0 31,964 0 31,964 Broker/other 0 63 284 347 Total other corporate 0 32,027 284 32,311 Total securities available for sale $ 34,727 $ 52,627 $ 570 $ 87,924 Equity securities, carried at fair value: Third party pricing vendor $ 925 $ 70 $ 0 $ 995 Broker/other 0 0 46 46 Total equity securities $ 925 $ 70 $ 46 $ 1,041 March 31, 2019 (In millions) Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Total Securities held to maturity, carried at amortized cost: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 27,629 $ 350 $ 0 $ 27,979 Total government and agencies 27,629 350 0 27,979 Municipalities: Third party pricing vendor 0 1,061 0 1,061 Total municipalities 0 1,061 0 1,061 Mortgage- and asset-backed securities: Third party pricing vendor 0 8 0 8 Broker/other 0 0 13 13 Total mortgage- and asset-backed securities 0 8 13 21 Public utilities: Third party pricing vendor 0 3,068 0 3,068 Total public utilities 0 3,068 0 3,068 Sovereign and supranational: Third party pricing vendor 0 1,332 0 1,332 Total sovereign and supranational 0 1,332 0 1,332 Banks/financial institutions: Third party pricing vendor 0 1,039 0 1,039 Total banks/financial institutions 0 1,039 0 1,039 Other corporate: Third party pricing vendor 0 2,946 0 2,946 Total other corporate 0 2,946 0 2,946 Total securities held to maturity $ 27,629 $ 9,804 $ 13 $ 37,446 December 31, 2018 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities available for sale, carried at fair value: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 32,993 $ 1,349 $ 0 $ 34,342 Total government and agencies 32,993 1,349 0 34,342 Municipalities: Third party pricing vendor 0 1,863 0 1,863 Total municipalities 0 1,863 0 1,863 Mortgage- and asset-backed securities: Third party pricing vendor 0 162 0 162 Broker/other 0 0 177 177 Total mortgage- and asset-backed securities 0 162 177 339 Public utilities: Third party pricing vendor 0 7,062 0 7,062 Broker/other 0 0 109 109 Total public utilities 0 7,062 109 7,171 Sovereign and supranational: Third party pricing vendor 0 1,260 0 1,260 Total sovereign and supranational 0 1,260 0 1,260 Banks/financial institutions: Third party pricing vendor 0 8,895 0 8,895 Broker/other 0 0 23 23 Total banks/financial institutions 0 8,895 23 8,918 Other corporate: Third party pricing vendor 0 28,789 0 28,789 Broker/other 0 0 213 213 Total other corporate 0 28,789 213 29,002 Total securities available for sale $ 32,993 $ 49,380 $ 522 $ 82,895 Equity securities, carried at fair value: Third party pricing vendor $ 874 $ 67 $ 0 $ 941 Broker/other 0 0 46 46 Total equity securities $ 874 $ 67 $ 46 $ 987 December 31, 2018 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities held to maturity, carried at amortized cost: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 27,030 $ 8 $ 0 $ 27,038 Total government and agencies 27,030 8 0 27,038 Municipalities: Third party pricing vendor 0 469 0 469 Total municipalities 0 469 0 469 Mortgage- and asset-backed securities: Broker/other 0 0 15 15 Total mortgage- and asset-backed securities 0 0 15 15 Public utilities: Third party pricing vendor 0 2,973 0 2,973 Total public utilities 0 2,973 0 2,973 Sovereign and supranational: Third party pricing vendor 0 1,840 0 1,840 Total sovereign and supranational 0 1,840 0 1,840 Banks/financial institutions: Third party pricing vendor 0 1,583 0 1,583 Total banks/financial institutions 0 1,583 0 1,583 Other corporate: Third party pricing vendor 0 2,804 0 2,804 Total other corporate 0 2,804 0 2,804 Total securities held to maturity $ 27,030 $ 9,677 $ 15 $ 36,722 The following is a discussion of the determination of fair value of the Company's remaining financial instruments. Derivatives The Company uses derivative instruments to manage the risk associated with certain assets. However, the derivative instrument may not be classified in the same fair value hierarchy level as the associated asset. The Company uses pricing models to determine the estimated fair value of derivatives. Inputs used to value derivatives include, but are not limited to, interest rates, credit spreads, foreign currency forward and spot rates, and interest volatility. The significant inputs to pricing derivatives are generally observable in the market or can be derived by observable market data. When these inputs are observable, the derivatives are classified as Level 2. The fair values of the foreign currency forwards and options associated with certain investments; the foreign currency forwards and options used to hedge foreign exchange risk from the Company's net investment in Aflac Japan and economically hedge certain portions of forecasted cash flows denominated in yen; and the foreign currency swaps associated with certain senior notes are based on the amounts the Company would expect to receive or pay. The determination of the fair value of these derivatives is based on observable market inputs, therefore they are classified as Level 2. To determine the fair value of its interest rate derivatives, the Company uses inputs that are generally observable in the market or can be derived from observable market data. Interest rate swaps are cleared trades. In a cleared swap contract, the clearinghouse provides benefits to the counterparties similar to contracts listed for investment traded on an exchange since it maintains a daily margin to mitigate counterparties' credit risk. These derivatives are priced using observable inputs, accordingly, they are classified as Level 2. For its interest rate swaptions, the Company estimates their fair values using observable market data, including interest rate curves and volatilities. Their fair values are also classified as Level 2. For derivatives associated with VIEs where the Company is the primary beneficiary, the Company is not the direct counterparty to the swap contracts. As a result, the fair value measurements incorporate the credit risk of the collateral associated with the VIE. The Company receives valuations from a third party pricing vendor for these derivatives. Based on an analysis of these derivatives and a review of the methodology employed by the pricing vendor, the Company determined that due to the long duration of these swaps and the need to extrapolate from short-term observable data to derive and measure long-term inputs, certain inputs, assumptions and judgments are required to value future cash flows that cannot be corroborated by current inputs or current observable market data. As a result, the derivatives associated with the Company's consolidated VIEs are classified as Level 3 of the fair value hierarchy. Commercial mortgage and other loans Commercial mortgage and other loans include transitional real estate loans, commercial mortgage loans and middle market loans. The Company's loan receivables do not have readily determinable market prices and generally lack market liquidity. Fair values for loan receivables are determined based on the present value of expected future cash flows discounted at the applicable U.S. Treasury or London Interbank Offered Rate (LIBOR) yield plus an appropriate spread that considers other risk factors, such as credit and liquidity risk. These spreads are provided by the applicable asset managers based on their knowledge of the current loan pricing environment and market conditions. The spreads are a significant component of the pricing inputs and are generally considered unobservable. Therefore, these investments have been assigned a Level 3 within the fair value hierarchy. Other investments Other investments includes short-term investments that are measured at fair value where amortized cost approximates fair value. Other policyholders' funds The largest component of the other policyholders' funds liability is the Company's annuity line of business in Aflac Japan. The Company's annuities have fixed benefits and premiums. For this product, the Company estimates the fair value to be equal to the cash surrender value. This is analogous to the value paid to policyholders on the valuation date if they were to surrender their policy. The Company periodically checks the cash value against discounted cash flow projections for reasonableness. The Company considers its inputs for this valuation to be unobservable and have accordingly classified this valuation as Level 3. Notes payable During the three -month periods ended March 31, 2019 and 2018 , respectively, there were no transfers between Level 1 and 2 for assets and liabilities that are measured and carried at fair value on a recurring basis. The following tables present the changes in fair value of the Company's investments and derivatives carried at fair value classified as Level 3. Three Months Ended Fixed Maturity Securities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 177 $ 109 $ 23 $ 213 $ 46 $ 80 $ 0 $ 648 Realized investment gains (losses) included 0 0 0 0 0 (8 ) 0 (8 ) Unrealized gains (losses) included in other 1 1 0 1 0 (2 ) 0 1 Purchases, issuances, sales and settlements: Purchases 0 0 0 63 0 0 0 63 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 (2 ) 0 0 0 (2 ) Settlements 0 0 0 0 0 0 0 0 Transfers into Level 3 0 0 0 25 (2) 0 0 0 25 Transfers out of Level 3 0 (25 ) (2) 0 (16 ) (3) 0 0 0 (41 ) Balance, end of period $ 178 $ 85 $ 23 $ 284 $ 46 $ 70 $ 0 $ 686 Changes in unrealized gains (losses) relating earnings $ 0 $ 0 $ 0 $ 0 $ 0 $ (8 ) $ 0 $ (8 ) (1) Derivative assets and liabilities are presented net (2) Transfer due to sector classification change (3) Transfer due to availability of observable market inputs Three Months Ended Fixed Maturity Securities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 175 $ 68 $ 25 $ 146 $ 16 $ 22 $ 1 $ 453 Realized investment gains (losses) included in earnings 0 0 0 0 0 126 0 126 Unrealized gains (losses) included in other comprehensive income (loss) 11 (1 ) (1 ) (2 ) 0 6 0 13 Purchases, issuances, sales and settlements: Purchases 0 16 0 0 0 0 0 16 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 0 0 0 0 0 Settlements 0 0 0 (1 ) 0 0 0 (1 ) Transfers into Level 3 0 0 0 0 0 0 0 0 Transfers out of Level 3 0 0 0 0 0 0 0 0 Balance, end of period $ 186 $ 83 $ 24 $ 143 $ 16 $ 154 $ 1 $ 607 Changes in unrealized gains (losses) relating earnings $ 0 $ 0 $ 0 $ 0 $ 0 $ 126 $ 0 $ 126 (1) Level 3 Significant Unobservable Input Sensitivity The following tables summarize the significant unobservable inputs used in the valuation of the Company's Level 3 investments and derivatives carried at fair value. Included in the tables are the inputs or range of possible inputs that have an effect on the overall valuation of the financial instruments. March 31, 2019 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturity securities: Mortgage- and asset-backed securities $ 178 Consensus pricing Offered quotes N/A (a) Public utilities 85 Discounted cash flow Credit spreads N/A (a) Banks/financial institutions 23 Consensus pricing Offered quotes N/A (a) Other corporate 284 Discounted cash flow Credit spreads N/A (a) Equity securities 46 Net asset value Offered quotes N/A (a) Other assets: Foreign currency swaps 117 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) CDS spreads 13 - 109 bps 61 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) Total assets $ 794 Liabilities: Other liabilities: Foreign currency swaps $ 102 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) CDS spreads 30 - 187 bps 6 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) Total liabilities $ 108 (a) N/A represents securities where the Company receives unadjusted broker quotes and for which there is no transparency into the providers' valuation techniques or unobservable inputs. (b) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (c) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps December 31, 2018 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturity securities: Mortgage- and asset-backed securities $ 177 Consensus pricing Offered quotes N/A (a) Public utilities 109 Discounted cash flow Credit spreads N/A (a) Banks/financial institutions 23 Consensus pricing Offered quotes N/A (a) Other corporate 213 Discounted cash flow Credit spreads N/A (a) Equity securities 46 Net asset value Offered quotes N/A (a) Other assets: Foreign currency swaps 125 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) CDS spreads 19 - 120 bps 57 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) Total assets $ 750 Liabilities: Other liabilities: Foreign currency swaps $ 98 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) CDS spreads 28 - 211 bps 4 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) Total liabilities $ 102 (a) N/A represents securities where the Company receives unadjusted broker quotes and for which there is no transparency into the providers' valuation techniques or unobservable inputs. (b) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps Net Asset Value The Company holds certain unlisted equity securities whose fair value is derived based on the financial statements published by the investee. These securities do not trade on an active market and the valuations derived are dependent on the availability of timely financial reporting of the investee. Net asset value is an unobservable input in the determination of fair value of equity securities. Offered Quotes In circumstances where the Company's valuation model price is overridden because it implies a value that is not consistent with current market conditions, the Company will solicit bids from a limited number of brokers. The Company also receives unadjusted prices from brokers for its mortgage and asset-backed securities. These quotes are non-binding but are reflective of valuation best estimates at that particular point in time. Offered quotes are an unobservable input in the determination of fair value of mortgage- and asset-backed securities, certain banks/financial institutions, certain other corporate, and equity securities investments. Interest Rates and CDS Spreads The significant drivers of the valuation of the interest and foreign exchange swaps are interest rates and CDS spreads. Some of the Company's swaps have long maturities that increase the sensitivity of the swaps to interest rate fluctuations. For the Company's foreign exchange or cross currency swaps that are in a net asset position, an increase in yen interest rates (all other factors held constant) will decrease the present value of the yen final settlement receivable (receive leg), thus decreasing the value of the swap as long as the derivative remains in a net asset position. Foreign exchange swaps also have a lump-sum final settlement of foreign exchange principal amounts at the termination of the swap. Assuming all other factors are held constant, an increase in yen interest rates will decrease the receive leg and decrease the net value of the swap. Likewise, holding all other factors constant, an increase in U.S. dollar interest rates will increase the swap's net value due to the decrease in the present value of the dollar final settlement payable (pay leg). The extinguisher feature in most of the Company's VIE swaps results in a cessation of cash flows and no further payments between the parties to the swap in the event of a default on the referenced or underlying collateral. To price this feature, the Company applies the survival probability of the referenced entity to the projected cash flows. The survival probability uses the CDS spreads and recovery rates to adjust the present value of the cash flows. For extinguisher swaps with positive values, an increase in CDS spreads decreases the likelihood of receiving the final exchange payments and reduces the value of the swap. For additional information on the Company's investments and financial instruments, see the accompanying Notes 1, 3 and 4 and Notes 1, 3 and 4 of the Notes to the Consolidated Financial Statements in the 2018

POLICY LIABILITIES

POLICY LIABILITIES	3 Months Ended
	Mar. 31, 2019
Insurance Loss Reserves [Abstract]
POLICY LIABILITIES	POLICY LIABILITIES Changes in the liability for unpaid policy claims were as follows: Three Months Ended (In millions) 2019 2018 Unpaid supplemental health claims, beginning of period $ 3,952 $ 3,884 Less reinsurance recoverables 29 30 Net balance, beginning of period 3,923 3,854 Add claims incurred during the period related to: Current year 1,825 1,842 Prior years (167 ) (192 ) Total incurred 1,658 1,650 Less claims paid during the period on claims incurred during: Current year 506 518 Prior years 1,137 1,116 Total paid 1,643 1,634 Effect of foreign exchange rate changes on unpaid claims 0 142 Net balance, end of period 3,938 4,012 Add reinsurance recoverables 29 31 Unpaid supplemental health claims, end of period 3,967 4,043 Unpaid life claims, end of period 658 587 Total liability for unpaid policy claims $ 4,625 $ 4,630 The incurred claims development related to prior years reflects favorable claims experience compared to previous estimates. The favorable claims development of $167 million for the three -month period ended March 31, 2019 comprises approximately $91 million from Japan, which represents approximately 54% of the total. The impact of foreign currency exchange for the period December 31, 2018 to March 31, 2019 was immaterial. The Company has experienced continued favorable claim trends in 2019 for its core health products in Japan. The Company's experience in Japan related to the average length of stay in the hospital for cancer treatment has shown continued decline in the current period. In addition, cancer treatment patterns in Japan are continuing to be influenced by significant advances in early-detection techniques and by the increased use of pathological diagnosis rather than clinical exams. Additionally, follow-up radiation and chemotherapy treatments are occurring more often on an outpatient basis. Such changes in treatment not only increase the quality of life and initial outcomes for the patients, but also decrease the average length of each hospital stay, resulting in favorable claims development. The remainder of the favorable claims development related to prior years for the three -month period ended March 31, 2019

REINSURANCE

REINSURANCE	3 Months Ended
	Mar. 31, 2019
Reinsurance Disclosures [Abstract]
REINSURANCE	REINSURANCE The Company periodically enters into fixed quota-share coinsurance agreements with other companies in the normal course of business. For each of its reinsurance agreements, the Company determines whether the agreement provides indemnification against loss or liability relating to insurance risk in accordance with applicable accounting standards. Reinsurance premiums and benefits paid or provided are accounted for on bases consistent with those used in accounting for the original policies issued and the terms of the reinsurance contracts. Premiums and benefits are reported net of insurance ceded. The Company has recorded a deferred profit liability related to reinsurance transactions. The remaining deferred profit liability of $1.0 billion , as of March 31, 2019 , is included in future policy benefits in the consolidated balance sheet and is being amortized into income over the expected lives of the policies. The Company has also recorded a reinsurance recoverable for reinsurance transactions, which is included in other assets in the consolidated balance sheet and had a remaining balance of $944 million and $941 million as of March 31, 2019 , and December 31, 2018 , respectively. The increase in the reinsurance recoverable balance was driven by the growth in reserves related to the business that has been reinsured as the policies age. The ceded reserves increased approximately .3% from December 31, 2018 , to March 31, 2019 . The following table reconciles direct premium income and direct benefits and claims to net amounts after the effect of reinsurance. Three Months Ended (In millions) 2019 2018 Direct premium income $ 4,776 $ 4,833 Ceded to other companies: Ceded Aflac Japan closed blocks (121 ) (129 ) Other (15 ) (15 ) Assumed from other companies: Retrocession activities 50 54 Other 1 2 Net premium income $ 4,691 $ 4,745 Direct benefits and claims $ 3,041 $ 3,119 Ceded benefits and change in reserves for future benefits: Ceded Aflac Japan closed blocks (111 ) (117 ) Eliminations 10 12 Other (11 ) (12 ) Assumed from other companies: Retrocession activities 48 52 Eliminations (10 ) (12 ) Benefits and claims, net $ 2,967 $ 3,042 These reinsurance transactions are indemnity reinsurance that do not relieve the Company from its obligations to policyholders. In the event that the reinsurer is unable to meet their obligations, the Company remains liable for the reinsured claims. As a part of its capital contingency plan, the Company entered into a committed reinsurance facility agreement on December 1, 2015 in the amount of approximately 110 billion yen of reserves. This reinsurance facility agreement was renewed in 2018 and is effective until December 31, 2019. There are also additional commitment periods of a one-year duration, each of which are automatically extended unless notification is received from the reinsurer within 60 days prior to the expiration. The reinsurer can withdraw from the committed facility if Aflac‘s Standard and Poor's (S&P) rating drops below BBB-. As of March 31, 2019

NOTES PAYABLE AND LEASE OBLIGAT

NOTES PAYABLE AND LEASE OBLIGATIONS	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
NOTES PAYABLE AND LEASE OBLIGATIONS	NOTES PAYABLE AND LEASE OBLIGATIONS A summary of notes payable and lease obligations follows: (In millions) March 31, 2019 December 31, 2018 4.00% senior notes due February 2022 $ 348 $ 348 3.625% senior notes due June 2023 698 698 3.625% senior notes due November 2024 746 746 3.25% senior notes due March 2025 448 447 2.875% senior notes due October 2026 297 297 6.90% senior notes due December 2039 220 220 6.45% senior notes due August 2040 254 254 4.00% senior notes due October 2046 394 394 4.750% senior notes due January 2049 540 540 Yen-denominated senior notes and subordinated debentures: .932% senior notes due January 2027 (principal amount 60.0 billion yen) 538 538 1.159% senior notes due October 2030 (principal amount 29.3 billion yen) 262 262 1.488% senior notes due October 2033 (principal amount 15.2 billion yen) 136 136 1.750% senior notes due October 2038 (principal amount 8.9 billion yen) 79 79 2.108% subordinated debentures due October 2047 (principal amount 60.0 billion yen) 536 536 Yen-denominated loans: Variable interest rate loan due September 2021 (.32% in 2019 and 2018, principal amount 5.0 billion yen) 45 45 Variable interest rate loan due September 2023 (.47% in 2019 and 2018, principal amount 25.0 billion yen) 225 225 Finance lease obligations payable through 2025 12 13 Operating lease obligations payable through 2028 (1) 122 0 Total notes payable and lease obligations $ 5,900 $ 5,778 (1) See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2019 related to leases. Amounts in the table above are reported net of debt issuance costs and issuance premiums or discounts, if applicable, that are being amortized over the life of the notes. The following table presents the contractual maturities and present value of lease liabilities. March 31, 2019 (In millions) Operating Leases Finance Leases Total 2019 $ 33 $ 3 $ 36 2020 30 3 33 2021 20 2 22 2022 17 2 19 2023 9 1 10 After 2023 24 1 25 Total lease payments $ 133 $ 12 $ 145 Less: Interest $ 11 $ 0 $ 11 Present value of lease liabilities $ 122 $ 12 $ 134 The following table presents the weighted average remaining lease term and weighted average discount rate for lease liabilities. March 31, 2019 Weighted average remaining lease term (years): Operating leases 4.4 Finance leases 3.8 Weighted average discount rate: Operating leases 2.55 % Finance leases 1.56 % Operating lease cost for the three-month period ended March 31, 2019 was $14 million . Operating cash outflow for operating leases for the three-month period ended March 31, 2019 was $14 million March 31, 2019 follows: Borrower Type Term Expiration Date Capacity Amount Outstanding Interest Rate on Borrowed Amount Maturity Period Commitment Fee Business Purpose Aflac Incorporated uncommitted bilateral 364 days December 27, 2019 $100 million $0 million The rate quoted by the bank and agreed upon at the time of borrowing Up to 3 months None General corporate purposes Aflac Incorporated unsecured revolving 5 years March 29, 2024, or the date commitments are terminated pursuant to an event of default 100.0 billion yen 0.0 billion yen A rate per annum equal to (a) Tokyo interbank market rate (TIBOR) plus, the alternative applicable TIBOR margin during the availability period from the closing date to the commitment termination date or (b) the TIBOR rate offered by the agent to major banks in yen for the applicable period plus, the applicable alternative TIBOR margin during the term out period No later than .30% to .50%, depending on the Parent Company's debt ratings as of the date of determination General corporate purposes, including a capital contingency plan for the operations of the Parent Company Aflac Incorporated unsecured revolving 5 years April 4, 2023, or the date commitments are terminated pursuant to an event of default 55.0 billion yen, or the equivalent amount in U.S. dollars 0.0 billion yen A rate per annum equal to, at the Company's option, either, (a) London Interbank Offered Rate (LIBOR) adjusted for certain costs or (b) a base rate determined by reference to the highest of (1) the federal funds rate plus 1/2 of 1%, (2) the rate of interest for such day announced by Mizuho Bank, Ltd. as its prime rate, or (3) the eurocurrency rate for an interest period of one month plus 1.00%, in each case plus an applicable margin No later than April 4, 2023 .085% to .225%, depending on the Parent Company's debt ratings as of the date of determination General corporate purposes, including a capital contingency plan for the operations of the Parent Company Aflac Incorporated uncommitted bilateral None specified None specified $50 million $0 million A rate per annum equal to, at the Parent Company's option, either (a) a eurocurrency rate determined by reference to the agent's LIBOR for the interest period relevant to such borrowing or (b) the base rate determined by reference to the greater of (i) the prime rate as determined by the agent, and (ii) the sum of 0.50% and the federal funds rate for such day Up to 3 months None General corporate purposes Aflac (1) uncommitted revolving 364 days November 29, 2019 $250 million $0 million USD three-month LIBOR plus 75 basis points per annum 3 months None General corporate purposes Aflac Incorporated (1) uncommitted revolving 364 days April 2, 2019 (2) 50.0 billion yen 0.0 billion yen Three-month TIBOR plus 80 basis points per annum 3 months None General corporate purposes (1) Intercompany credit agreement (2) Renewed in April 2019 with an expiration date of April 2, 2020 The Company was in compliance with all of the covenants of its notes payable and lines of credit at March 31, 2019 . No events of default or defaults occurred during the three -month period ended March 31, 2019 . For additional information, see Notes 4 and 9 of the Notes to the Consolidated Financial Statements in the 2018

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
SHAREHOLDERS' EQUITY	SHAREHOLDERS’ EQUITY The following table is a reconciliation of the number of shares of the Company's common stock for the three -month periods ended March 31 . (In thousands of shares) 2019 2018 Common stock - issued: Balance, beginning of period 1,347,540 1,345,762 Exercise of stock options and issuance of restricted shares 1,060 1,014 Balance, end of period 1,348,600 1,346,776 Treasury stock: Balance, beginning of period 592,254 564,852 Purchases of treasury stock: Open market 10,237 6,640 Other 561 315 Dispositions of treasury stock: Shares issued to AFL Stock Plan (430 ) (384 ) Exercise of stock options (231 ) (305 ) Other (278 ) (99 ) Balance, end of period 602,113 571,019 Shares outstanding, end of period 746,487 775,757 Outstanding share-based awards are excluded from the calculation of weighted-average shares used in the computation of basic earnings per share (EPS). The following table presents the approximate number of share-based awards to purchase shares, on a weighted-average basis, that were considered to be anti-dilutive and were excluded from the calculation of diluted earnings per share for the following periods. Three Months Ended (In thousands) 2019 2018 Anti-dilutive share-based awards 22 9 Share Repurchase Program During the first three months of 2019 , the Company repurchased 10.2 million shares of its common stock in the open market for $490 million as part of its share repurchase program. During the first three months of 2018 , the Company repurchased 6.6 million shares of its common stock in the open market for $296 million as part of its share repurchase program. As of March 31, 2019 , a remaining balance of 58.8 million shares of the Company's common stock was available for purchase under share repurchase authorizations by its board of directors. Reclassifications from Accumulated Other Comprehensive Income The tables below are reconciliations of accumulated other comprehensive income by component for the following periods. Changes in Accumulated Other Comprehensive Income Three Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Total Balance, beginning of period $ (1,847 ) $ 4,234 $ (24 ) $ (212 ) $ 2,151 Other comprehensive (1 ) 2,340 (2 ) 3 2,340 Amounts reclassified from 0 (13 ) 0 3 (10 ) Net current-period other (1 ) 2,327 (2 ) 6 2,330 Balance, end of period $ (1,848 ) $ 6,561 $ (26 ) $ (206 ) $ 4,481 All amounts in the table above are net of tax. Three Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Liability Adjustment Total Balance, beginning of period $ (1,750 ) $ 5,964 $ (23 ) $ (163 ) $ 4,028 Other comprehensive 447 (983 ) 2 (37 ) (571 ) Amounts reclassified from 0 225 (1) 0 3 228 Net current-period other 447 (758 ) 2 (34 ) (343 ) Balance, end of period $ (1,303 ) $ 5,206 $ (21 ) $ (197 ) $ 3,685 (1) Includes amounts reclassified due to changes in accounting principles of $(148) related to financial instruments and $374 related to tax effects from tax reform All amounts in the table above are net of tax. The tables below summarize the amounts reclassified from each component of accumulated other comprehensive income into net earnings for the following periods. Reclassifications Out of Accumulated Other Comprehensive Income (In millions) Three Months Ended Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Unrealized gains (losses) on available-for-sale $ 0 Other-than-temporary impairment 17 Other gains (losses) 17 Total before tax (4 ) Tax (expense) or benefit (1) $ 13 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (4 ) Acquisition and operating expenses (2) Prior service (cost) credit 0 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (3 ) Net of tax Total reclassifications for the period $ 10 Net of tax (1) Based on 25% blended tax rate (2) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 11 for additional details). (In millions) Three Months Ended Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Unrealized gains (losses) on available-for-sale $ 0 Other-than-temporary impairment 2 Other gains (losses) 2 Total before tax (1 ) Tax (expense) or benefit (1) $ 1 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (4 ) Acquisition and operating expenses (2) Prior service (cost) credit 0 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (3 ) Net of tax Total reclassifications for the period $ (2 ) Net of tax (1) Based on 27% blended tax rate (2)

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION As of March 31, 2019 , the Company has outstanding share-based awards under the Aflac Incorporated Long-Term Incentive Plan (the Plan). Share-based awards are designed to reward employees for their long-term contributions to the Company and provide incentives for them to remain with the Company. The number and frequency of share-based awards are based on competitive practices, operating results of the Company, government regulations, and other factors. The Plan, as amended on February 14, 2017, allows for a maximum number of shares issuable over its term of 75 million shares including 38 million shares that may be awarded in respect of awards other than options or stock appreciation rights. If any awards granted under the Plan are forfeited or are terminated before being exercised or settled for any reason other than tax forfeiture, then the shares underlying the awards will again be available under the Plan. The Plan allows awards to Company employees for incentive stock options (ISOs), non-qualifying stock options (NQSOs), restricted stock, restricted stock units, and stock appreciation rights. Non-employee directors are eligible for grants of NQSOs, restricted stock, and stock appreciation rights. As of March 31, 2019 , approximately 39.4 million shares were available for future grants under this plan. The ISOs and NQSOs have a term of 10 years , and the share-based awards generally vest upon time-based conditions or time and performance-based conditions. Time-based vesting generally occurs after three years . Performance-based vesting conditions generally include the attainment of goals related to Company financial performance. As of March 31, 2019 , the only performance-based awards issued and outstanding were restricted stock awards. Stock options and stock appreciation rights granted under the amended Plan have an exercise price of at least the fair market value of the underlying stock on the grant date and have an expiration date no later than 10 years from the grant date. Time-based restricted stock awards, restricted stock units and stock options granted after January 1, 2017 generally vest on a ratable basis over three years , and awards granted prior to the amendment vest on a three years cliff basis. The Compensation Committee of the Board of Directors has the discretion to determine vesting schedules . Share-based awards granted to U.S.-based grantees are settled with authorized but unissued Company stock, while those issued to Japan-based grantees are settled with treasury shares. The following table provides information on stock options outstanding and exercisable at March 31, 2019 . Stock Weighted-Average Aggregate Weighted-Average Outstanding 4,558 5.0 $ 94 $ 29.36 Exercisable 4,097 4.6 88 28.54 The Company received cash from the exercise of stock options in the amount of $17 million during the first three months of 2019, compared with $23 million in the first three months of 2018. The tax benefit realized as a result of stock option exercises and restricted stock releases was $22 million in the first three months of 2019, compared with $12 million in the first three months of 2018. As of March 31, 2019 , total compensation cost not yet recognized in the Company's financial statements related to restricted stock awards was $70 million , of which $33 million ( 824 thousand shares) was related to restricted stock awards with a performance-based vesting condition. The Company expects to recognize these amounts over a weighted-average period of approximately 1.4 years . There are no other contractual terms covering restricted stock awards once vested. The following table summarizes restricted stock activity during the three -month period ended March 31 . (In thousands of shares) Shares Weighted-Average Grant-Date Fair Value Per Share Restricted stock at December 31, 2018 3,407 $ 36.52 Granted in 2019 940 49.17 Canceled in 2019 (18 ) 37.98 Vested in 2019 (1,732 ) 32.16 Restricted stock at March 31, 2019 2,597 $ 44.02 In February 2019, the Company granted 399 thousand performance-based stock awards, which are contingent on the achievement of the Company's financial performance metrics and its market-based conditions. On the date of grant, the Company estimated the fair value of restricted stock awards with market-based conditions using a Monte Carlo simulation model. The model discounts the value of the stock at the assumed vesting date based on the risk-free interest rate. Based on estimates of actual performance versus the vesting thresholds, the calculated fair value percentage pay-out estimate will be updated each quarter. The Company uses third-party analyses to assist in developing the assumptions used in, as well as calibrating, a Monte Carlo simulation model. The Company is responsible for determining the assumptions used in estimating the fair value of its share-based payment awards. For additional information on the Company's long-term share-based compensation plans and the types of share-based awards, see Note 12 of the Notes to the Consolidated Financial Statements included in the 2018

BENEFIT PLANS

BENEFIT PLANS	3 Months Ended
	Mar. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
BENEFIT PLANS	BENEFIT PLANS The Company has funded defined benefit plans in Japan and the United States, however the U.S. plan was frozen to new participants effective October 1, 2013. The Company also maintains non-qualified, unfunded supplemental retirement plans that provide defined pension benefits in excess of limits imposed by federal tax law for certain Japanese, U.S. and former employees, however the U.S. plan was frozen to new participants effective January 1, 2015. U.S. employees who are not participants in the defined benefit plan receive a nonelective 401(k) employer contribution. The Company provides certain health care benefits for eligible U.S. retired employees, their beneficiaries and covered dependents (other postretirement benefits). The health care plan is contributory and unfunded. Effective January 1, 2014, employees eligible for benefits included the following: (1) active employees whose age plus service, in years, equaled or exceeded 80 (rule of 80 ); (2) active employees who were age 55 or older and have met the 15 years of service requirement; (3) active employees who would meet the rule of 80 in the next 5 years ; (4) active employees who were age 55 or older and who would meet the 15 years of service requirement within the next 5 years ; and (5) current retirees. For certain employees and former employees, additional coverage is provided for all medical expenses for life. Pension and other postretirement benefit expenses are included in acquisition and operating expenses in the consolidated statement of earnings, which includes other components of net periodic pension cost and postretirement costs (other than service costs) of $5 million for both the periods ended March 31, 2019 and 2018 . Total net periodic cost includes the following components: Three Months Ended March 31, Pension Benefits Japan U.S. (In millions) 2019 2018 2019 2018 Components of net periodic Service cost $ 5 $ 5 $ 6 $ 7 Interest cost 1 2 9 9 Expected return on plan (2 ) (2 ) (7 ) (7 ) Amortization of net actuarial 1 0 3 4 Net periodic (benefit) cost $ 5 $ 5 $ 11 $ 13 During the three months ended March 31, 2019 , Aflac Japan contributed approximately $9 million (using the weighted-average yen/dollar exchange rate for the three -month period ending March 31, 2019 ) to the Japanese funded defined benefit plan, and Aflac U.S. contributed $10 million to the U.S. funded defined benefit plan. For additional information regarding the Company's Japanese and U.S. benefit plans, see Note 14 of the Notes to the Consolidated Financial Statements in the 2018

COMMITMENTS AND CONTINGENT LIAB

COMMITMENTS AND CONTINGENT LIABILITIES	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENT LIABILITIES	COMMITMENTS AND CONTINGENT LIABILITIES Effective for 2019, the Company entered into an outsourcing agreement with an information technology and data services company to provide application maintenance and development services for its Japanese operation. As of March 31, 2019 , the agreement has a remaining term of five years and an aggregate remaining cost of 9.7 billion yen ( $87 million using the March 31, 2019 , exchange rate). The Company is a defendant in various lawsuits considered to be in the normal course of business. Members of the Company's senior legal and financial management teams review litigation on a quarterly and annual basis. The final results of any litigation cannot be predicted with certainty. Although some of this litigation is pending in states where large punitive damages, bearing little relation to the actual damages sustained by plaintiffs, have been awarded in recent years, the Company believes the outcome of pending litigation will not have a material adverse effect on its financial position, results of operations, or cash flows. See Note 3 of the Notes to the Consolidated Financial Statements for details on certain investment commitments. Guaranty Fund Assessments The United States insurance industry has a policyholder protection system that is monitored and regulated by state insurance departments. These life and health insurance guaranty associations are state entities (in all 50 states as well as Puerto Rico and the District of Columbia) created to protect policyholders of an insolvent insurance company. All insurance companies (with limited exceptions) licensed to sell life or health insurance in a state must be members of that state’s guaranty association. Under state guaranty association laws, certain insurance companies can be assessed (up to prescribed limits) for certain obligations to the policyholders and claimants of impaired or insolvent insurance companies that write the same line or similar lines of business. In 2009, the Pennsylvania Insurance Commissioner placed long-term care insurer Penn Treaty Network America Insurance Company and its subsidiary American Network Insurance Company (collectively referred to as Penn Treaty), neither of which is affiliated with Aflac, in rehabilitation and petitioned a state court for approval to liquidate Penn Treaty. A final order of liquidation was granted by a recognized judicial authority on March 1, 2017, and as a result, Penn Treaty is in the process of liquidation. The Company estimated and recognized the impact of its share of guaranty fund assessments resulting from the liquidation using a discounted rate of 4.25% . The Company recognized a discounted liability for the assessments of $62 million (undiscounted $94 million ), offset by discounted premium tax credits of $48 million (undiscounted $74 million ), for a net $14 million impact to net income in the quarter ended March 31, 2017. The Company paid a majority of these assessments by March 31, 2019. The Company used the cost estimate provided as of the liquidation date by the National Organization of Life and Health Guaranty Associations (NOLHGA) to calculate its estimated assessments and tax credits. Guaranty fund assessments for the three-month period ended March 31, 2019

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On April 12, 2019, the Company announced that ALIJ priced 30.0 billion yen (par value) of perpetual subordinated bonds. These bonds will bear interest at a fixed rate of .963% per annum and then at six-month Euro Yen LIBOR plus an applicable spread on and after the day immediately following April 18, 2024.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business Aflac Incorporated (the Parent Company) and its subsidiaries (collectively, the Company) primarily sell supplemental health and life insurance in the United States and Japan. The Company's insurance business is marketed and administered through American Family Life Assurance Company of Columbus (Aflac) in the United States and, effective April 1, 2018, through Aflac Life Insurance Japan Ltd. (ALIJ) in Japan. Prior to April 1, 2018, the Company's insurance business was marketed in Japan as a branch of Aflac. The Company’s operations consist of two reportable business segments: Aflac U.S., which includes Aflac, and Aflac Japan, which includes ALIJ. American Family Life Assurance Company of New York (Aflac New York) is a wholly owned subsidiary of Aflac. Most of Aflac's policies are individually underwritten and marketed through independent agents. Additionally, Aflac U.S. markets and administers group products through Continental American Insurance Company (CAIC), branded as Aflac Group Insurance. The Company's insurance operations in the United States and Japan service the two markets for the Company's insurance business. Aflac Japan's revenues, including realized gains and losses on its investment portfolio, accounted for 68% and 71% of the Company's total revenues in the three -month periods ended March 31, 2019 and 2018 , respectively. The percentage of the Company's total assets attributable to Aflac Japan was 84% at March 31, 2019 and December 31, 2018 , respectively. Basis of Presentation The Company prepares its financial statements in accordance with U.S. generally accepted accounting principles (U.S. GAAP). These principles are established primarily by the Financial Accounting Standards Board (FASB). In these Notes to the Consolidated Financial Statements, references to U.S. GAAP issued by the FASB are derived from the FASB Accounting Standards Codification TM (ASC). The preparation of financial statements in conformity with U.S. GAAP requires the Company to make estimates based on currently available information when recording transactions resulting from business operations. The most significant items on the Company's balance sheet that involve a greater degree of accounting estimates and actuarial determinations subject to changes in the future are the valuation of investments and derivatives, deferred policy acquisition costs (DAC), liabilities for future policy benefits and unpaid policy claims, and income taxes. These accounting estimates and actuarial determinations are sensitive to market conditions, investment yields, mortality, morbidity, commission and other acquisition expenses, and terminations by policyholders. As additional information becomes available, or actual amounts are determinable, the recorded estimates will be revised and reflected in operating results. Although some variability is inherent in these estimates, the Company believes the amounts provided are adequate. The unaudited consolidated financial statements include the accounts of the Parent Company, its subsidiaries and those entities required to be consolidated under applicable accounting standards. All material intercompany accounts and transactions have been eliminated. In the opinion of management, the accompanying unaudited consolidated financial statements of the Company contain all adjustments, consisting of normal recurring accruals, which are necessary to fairly present the consolidated balance sheets as of March 31, 2019 , and December 31, 2018 , the consolidated statements of earnings and comprehensive income (loss), shareholders' equity and cash flows for the three -month periods ended March 31, 2019 and 2018 . Results of operations for interim periods are not necessarily indicative of results for the entire year. As a result, these financial statements should be read in conjunction with the financial statements and notes thereto included in the Company's annual report on Form 10-K for the year ended December 31, 2018 ( 2018 Annual Report).
Reclassifications	Reclassifications : Certain reclassifications have been made to prior-year amounts to conform to current-year reporting classifications. These reclassifications had no impact on net earnings or total shareholders' equity.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Standard Description Date of Adoption Effect on Financial Statements or Other Significant Matters Accounting Standard Update (ASU) 2018-15 Intangibles - Goodwill and Other - Internal-Use Software, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract In August 2018, the FASB issued amendments to align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. Early adopted as of January 1, 2019 The adoption of this guidance did not have a significant impact on the Company’s financial position, results of operations or disclosures Standard Description Date of Adoption Effect on Financial Statements or Other Significant Matters ASU 2016-02 Leases as clarified and amended by: ASU 2018-01, Leases: Land Easement Practical Expedient for Transition to Topic 842, ASU 2018-10 , Codification Improvements to Topic 842, Leases, ASU 2018-11 , Leases, Targeted Improvements, and ASU 2018-20 , Leases: Narrow-Scope Improvements for Lessors In February 2016, the FASB issued updated guidance for accounting for leases (“Leases Update”). Per the Leases Update, lessees are required to recognize all leases on the balance sheet with the exception of short-term leases. A lease liability will be recorded for the obligation of a lessee to make lease payments arising from a lease. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The Leases Update provided a number of optional practical expedients. The Company elected the "package of practical expedients," which permits the Company not to reassess under the new standard its prior conclusions about lease identification, lease classification and initial direct costs. Under the Leases Update, lessor accounting is largely unchanged. In January 2018, an amendment was issued to the Leases Update which provided an entity with the option to elect a transition practical expedient to not evaluate land easements that exist or expired before the entity's adoption of the Leases Update and that were not previously accounted for as leases. In July 2018, the FASB issued two amendments to the Leases Update which clarified, corrected errors in, or made minor improvements to the Leases Update and provided entities with an optional transition method to adopt the Leases Update by recording a cumulative-effect adjustment to beginning retained earnings. Additionally, the amendments provided lessors with a practical expedient to not separate nonlease components from associated lease components and instead account for those components as a single component under certain conditions. In December 2018, an amendment to the Leases Update was issued to clarify: 1) lessor accounting for all sales (and other similar) taxes; 2) the handling of certain lessor costs when the amount of those costs is not readily determinable; and 3) lessor allocation of certain variable payments to the lease and non-lease components. January 1, 2019 The Company has operating and finance leases for office space and equipment. The Company elected the short-term lease exemption for all classes of leases which allows the Company to not recognize right-of-use assets and lease liabilities on the consolidated balance sheet and allows the Company to recognize the lease expense for short-term leases on a straight-line basis over the lease term. The Company elected the practical expedient to not separate lease and non-lease components and applied it to all classes of leases where the non-lease components are not significant. Some of the Company's leases include options to extend or terminate the lease and the lease terms may include such options when it is reasonably certain that the Company will exercise that option. Certain leases also include options to purchase the leased property. The leases within scope of the Leases Update increased the Company's right-of-use assets and lease liabilities recorded in its consolidated balance sheet by $134 million. As of January 1, 2019, the Company did not have land easements, but has elected the practical expedient as a safe harbor. The Company elected the optional transition method and as a safe harbor, the practical expedient provided to lessors. The Company has made an accounting policy election to exclude amounts collected from customers for all sales (and other similar) taxes from the transaction price. The adoption of the Leases Update and related amendments did not have a significant impact on the Company's financial position, results of operations, or disclosures.
Description of Accounting Pronouncements Pending Adoption	Accounting Pronouncements Pending Adoption Standard Description Effect on Financial Statements or Other Significant Matters ASU 2018-17 Consolidation: Targeted Improvements to Related Party Guidance for Variable Interest Entities In October 2018, the FASB issued targeted improvements which provide that indirect interests held through related parties under common control should be considered on a proportional basis for determining whether fees paid to decision makers and service providers are variable interests. The amendments are effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on the Company’s financial position, results of operations or disclosures. ASU 2018-14 Compensation - Retirement Benefits - Defined Benefit Plans - General, Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans In August 2018, the FASB issued amendments to modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. Accordingly, six disclosures requirements were removed, two added and two clarified. The amendments are effective for public business entities for fiscal years beginning after December 15, 2020. Early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on the Company’s financial position, results of operations, or disclosures. ASU 2018-13 Fair Value Measurement, Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement In August 2018, the FASB issued amendments to the disclosure requirements on fair value measurements. The amendments remove, modify, and add certain disclosures. The amendments are effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. Further, an entity is permitted to early adopt any removed or modified disclosures upon issuance of this update and delay adoption of the additional disclosures until their effective date. The adoption of this guidance is not expected to have a significant impact on the Company’s financial position, results of operations, or disclosures. ASU 2018-12 Financial Services - Insurance, Targeted Improvements to the Accounting for Long-Duration Contracts In August 2018, the FASB issued amendments that will significantly change how insurers account for long-duration contracts. The amendments will change existing recognition, measurement, presentation, and disclosure requirements. Issues addressed in the new guidance include: 1) a requirement to review and, if there is a change, update assumptions for the liability for future policy benefits at least annually, and to update the discount rate assumption quarterly, 2) accounting for market risk benefits at fair value, 3) simplified amortization for deferred acquisition costs, and 4) enhanced financial statement presentation and disclosures. The amendments are effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early application of the amendments is permitted. The Company is thoroughly evaluating the impact of adoption and expects that the adoption will have a significant impact on the Company’s financial position, results of operations, and disclosures. The Company anticipates that the requirement to update assumptions for liability for future policy benefits will have a significant impact on its results of operations, systems, processes and controls while the requirement to update the discount rate will have a significant impact on its equity. The Company has no products with market risk benefits. The Company does not expect to early adopt the updated standard. ASU 2017-04 Intangibles - Goodwill and Other: Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued amendments simplifying the subsequent measurement of goodwill. An entity, under this update, is no longer required to perform a hypothetical purchase price allocation to measure goodwill impairment. Instead, the entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The amendments are effective for public business entities that are SEC filers for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for any goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Standard Description Effect on Financial Statements or Other Significant Matters ASU 2016-13 Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued amendments that require a financial asset (or a group of financial assets) measured on an amortized cost basis to be presented net of an allowance for credit losses in order to reflect the amount expected to be collected on the financial asset(s). The measurement of expected credit losses is amended by replacing the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform about a credit loss. Credit losses on available-for-sale debt securities will continue to be measured in a manner similar to current U.S. GAAP; however, the amendments require that credit losses be presented as an allowance rather than as a write-down. Other amendments include changes to the balance sheet presentation and interest income recognition of purchased financial assets with a more-than-insignificant amount of credit deterioration since origination (PCD financial assets). The amendments are effective for public companies for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Companies may early adopt this guidance as of the fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The amendments will be adopted following a modified-retrospective approach resulting in a cumulative effect adjustment in retained earnings as of the beginning of the year of adoption. Two exceptions to this adoption method are for PCD financial assets and debt securities for which other-than-temporary impairment (OTTI) will have been recognized before the effective date. Loans purchased with credit deterioration accounted for under current U.S. GAAP as "purchased credit impaired" (PCI) financial assets will be classified as PCD financial assets at transition and PCD guidance will be applied prospectively. Debt securities that have experienced OTTI before the effective date will follow a prospective adoption method which allows an entity to maintain the same amortized cost basis before and after the effective date. The Company has identified certain financial instruments in scope of this guidance to include certain fixed maturity securities, loans and loan receivables and reinsurance recoverables (See Notes 3 and 7 for current balances of instruments in scope). The Company is continuing its progress towards updating its credit loss projection models and accounting systems in order to comply with the required changes in measurement of credit losses. The Company currently expects loans and loan receivables and held-to-maturity fixed maturity securities to be the asset classes most significantly impacted upon adoption of the guidance. The Company continues to evaluate the impact of adoption of this guidance on its financial position, results of operations, and disclosures.

BUSINESS SEGMENT INFORMATION (T

BUSINESS SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated	Information regarding operations by reportable segment and Corporate and other, follows: Three Months Ended (In millions) 2019 2018 Revenues: Aflac Japan: Net earned premiums $ 3,180 $ 3,263 Net investment income, less amortized hedge costs 610 588 Other income 12 12 Total Aflac Japan 3,802 3,863 Aflac U.S.: Net earned premiums 1,461 1,427 Net investment income 177 175 Other income 2 2 Total Aflac U.S. 1,640 1,604 Corporate and other 95 79 Total adjusted revenues 5,537 5,546 Realized investment gains (losses) (1),(2),(3) 120 (82 ) Total revenues $ 5,657 $ 5,464 (1) Amortized hedge costs of $62 and $55 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency exposure management strategies have been reclassified from realized investment gains (losses) and reported as a deduction from net investment income when analyzing operations. (2) Amortized hedge income of $20 and $2 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency exposure management strategies has been reclassified from realized investment gains (losses) and reported as an increase to net investment income when analyzing operations. (3) Net interest cash flows from derivatives associated with certain investment strategies of $(7) for the three -month period ended March 31, 2019 and an immaterial amount in 2018, respectively, have been reclassified from realized investment gains (losses) and included in adjusted earnings as a component of net investment income.
Reconciliation of Adjusted Profit (Loss) from Segments to Consolidated	Three Months Ended (In millions) 2019 2018 Pretax earnings: Aflac Japan $ 834 $ 818 Aflac U.S. 323 337 Corporate and other (18 ) (46 ) Pretax adjusted earnings 1,139 1,109 Realized investment gains (losses) (1),(2),(3),(4) 103 (98 ) Other income (loss) 0 (29 ) Total earnings before income taxes $ 1,242 $ 982 Income taxes applicable to pretax adjusted earnings $ 291 $ 289 Effect of foreign currency translation on after-tax (8 ) 21 (1) Amortized hedge costs of $62 and $55 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency management strategies have been reclassified from realized investment gains (losses) and reported as a deduction from pretax adjusted earnings when analyzing operations. (2) Amortized hedge income of $20 and $2 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to certain foreign currency management strategies has been reclassified from realized investment gains (losses) and reported as an increase in pretax adjusted earnings when analyzing operations. (3) Net interest cash flows from derivatives associated with certain investment strategies of $(7) for the three -month period ended March 31, 2019 and an immaterial amount in 2018, respectively, have been reclassified from realized investment gains (losses) and included in adjusted earnings as a component of net investment income. (4) A gain of $17 and $17 for the three -month periods ended March 31, 2019 , and 2018 , respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable have been reclassified from realized investment gains (losses) and included in adjusted earnings when analyzing operations
Reconciliation of Assets from Segment to Consolidated	Assets were as follows: (In millions) March 31, December 31, Assets: Aflac Japan $ 123,042 $ 118,342 Aflac U.S. 19,965 19,100 Corporate and other 2,672 2,964 Total assets $ 145,679 $ 140,406

INVESTMENTS (Tables)

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Available-for-Sale Debt Securities	The amortized cost for the Company's investments in fixed maturity securities, the cost for equity securities and the fair values of these investments are shown in the following tables. March 31, 2019 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value Fixed maturity securities: Yen-denominated: Japan government and agencies $ 31,238 $ 4,813 $ 2 $ 36,049 Municipalities 509 93 3 599 Mortgage- and asset-backed securities 233 27 0 260 Public utilities 1,822 344 0 2,166 Sovereign and supranational 740 65 0 805 Banks/financial institutions 5,664 597 139 6,122 Other corporate 5,043 824 20 5,847 Total yen-denominated 45,249 6,763 164 51,848 U.S. dollar-denominated: U.S. government and agencies 190 11 1 200 Municipalities 1,204 105 0 1,309 Mortgage- and asset-backed securities 147 7 0 154 Public utilities 3,841 522 32 4,331 Sovereign and supranational 276 73 0 349 Banks/financial institutions 2,798 484 13 3,269 Other corporate 25,001 2,061 598 26,464 Total U.S. dollar-denominated 33,457 3,263 644 36,076 Total securities available for sale $ 78,706 $ 10,026 $ 808 $ 87,924 December 31, 2018 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value through other comprehensive income: Fixed maturity securities: Yen-denominated: Japan government and agencies $ 30,637 $ 3,700 $ 140 $ 34,197 Municipalities 385 32 9 408 Mortgage- and asset-backed securities 155 22 0 177 Public utilities 1,732 280 4 2,008 Sovereign and supranational 826 123 0 949 Banks/financial institutions 5,440 502 238 5,704 Other corporate 4,852 649 44 5,457 Total yen-denominated 44,027 5,308 435 48,900 U.S dollar-denominated: U.S. government and agencies 137 9 1 145 Municipalities 1,343 120 8 1,455 Mortgage- and asset-backed securities 155 8 1 162 Public utilities 4,772 496 105 5,163 Sovereign and supranational 251 60 0 311 Banks/financial institutions 2,860 389 35 3,214 Other corporate 23,311 1,343 1,109 23,545 Total U.S. dollar-denominated 32,829 2,425 1,259 33,995 Total securities available for sale $ 76,856 $ 7,733 $ 1,694 $ 82,895
Held-to-maturity Securities	March 31, 2019 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturity securities: Yen-denominated: Japan government and agencies $ 21,961 $ 6,018 $ 0 $ 27,979 Municipalities 814 247 0 1,061 Mortgage- and asset-backed securities 20 1 0 21 Public utilities 2,728 340 0 3,068 Sovereign and supranational 1,154 178 0 1,332 Banks/financial institutions 949 100 10 1,039 Other corporate 2,537 414 5 2,946 Total yen-denominated 30,163 7,298 15 37,446 Total securities held to maturity $ 30,163 $ 7,298 $ 15 $ 37,446 December 31, 2018 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturity securities: Yen-denominated: Japan government and agencies $ 21,712 $ 5,326 $ 0 $ 27,038 Municipalities 359 110 0 469 Mortgage- and asset-backed securities 14 1 0 15 Public utilities 2,727 254 8 2,973 Sovereign and supranational 1,551 289 0 1,840 Banks/financial institutions 1,445 158 20 1,583 Other corporate 2,510 332 38 2,804 Total yen-denominated 30,318 6,470 66 36,722 Total securities held to maturity $ 30,318 $ 6,470 $ 66 $ 36,722
Equity securities, FV-NI	March 31, 2019 December 31, 2018 (In millions) Fair Value Fair Value Equity securities, carried at fair value through net earnings: Equity securities: Yen-denominated $ 662 $ 641 U.S. dollar-denominated 379 346 Total equity securities $ 1,041 $ 987
Investments Classified by Contractual Maturity Date	The contractual and economic maturities of the Company's investments in fixed maturity securities at March 31, 2019 , were as follows: (In millions) Amortized Fair Available for sale: Due in one year or less $ 889 $ 950 Due after one year through five years 8,483 8,624 Due after five years through 10 years 10,111 11,034 Due after 10 years 58,843 66,902 Mortgage- and asset-backed securities 380 414 Total fixed maturity securities available for sale $ 78,706 $ 87,924 Held to maturity: Due in one year or less $ 135 $ 137 Due after one year through five years 1,112 1,187 Due after five years through 10 years 678 739 Due after 10 years 28,218 35,362 Mortgage- and asset-backed securities 20 21 Total fixed maturity securities held to maturity $ 30,163 $ 37,446
Investment Exposures Exceeding Ten Percent Shareholders Equity	Investment exposures that individually exceeded 10% of shareholders' equity were as follows: March 31, 2019 December 31, 2018 (In millions) Credit Amortized Fair Credit Amortized Fair Japan National Government (1) A+ $51,775 $62,275 A+ $51,207 $59,945 (1) Japan Government Bonds (JGBs) or JGB-backed securities
Gain (Loss) on Investments	Information regarding pretax realized gains and losses from investments is as follows: Three Months Ended (In millions) 2019 2018 Realized investment gains (losses): Fixed maturity securities: Available for sale: Gross gains from sales $ 12 $ 10 Gross losses from sales (8 ) (2 ) Foreign currency gains (losses) on sales and redemptions 13 (5 ) Total fixed maturity securities 17 3 Equity securities 58 (46 ) Loan receivables: Loan loss reserves (2 ) (7 ) Total loan receivables (2 ) (7 ) Derivatives and other: Derivative gains (losses) 0 144 Foreign currency gains (losses) (2 ) (228 ) Total derivatives and other (2 ) (84 ) Total realized investment gains (losses) $ 71 $ (134 )
Net Effect on Shareholders' Equity of Unrealized Gains and Losses from Investment Securities	The net effect on shareholders’ equity of unrealized gains and losses from fixed maturity securities was as follows: (In millions) March 31, 2019 December 31, Unrealized gains (losses) on securities available for sale $ 9,218 $ 6,039 Deferred income taxes (2,657 ) (1,805 ) Shareholders’ equity, unrealized gains (losses) on fixed maturity securities $ 6,561 $ 4,234
Investments Gross Unrealized Loss Aging	The following tables show the fair values and gross unrealized losses of the Company's available-for-sale and held-to-maturity investments that were in an unrealized loss position, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position. March 31, 2019 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. government and U.S. dollar-denominated $ 65 $ 1 $ 65 $ 1 $ 0 $ 0 Japan government and Yen-denominated 139 2 139 2 0 0 Municipalities: Yen-denominated 70 3 70 3 0 0 Mortgage- and asset- U.S. dollar-denominated 53 0 53 0 0 0 Public utilities: U.S. dollar-denominated 808 32 306 14 502 18 Banks/financial institutions: U.S. dollar-denominated 345 13 209 10 136 3 Yen-denominated 2,229 149 2,229 149 0 0 Other corporate: U.S. dollar-denominated 9,182 598 3,149 213 6,033 385 Yen-denominated 525 25 525 25 0 0 Total $ 13,416 $ 823 $ 6,745 $ 417 $ 6,671 $ 406 December 31, 2018 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. government and U.S. dollar-denominated $ 67 $ 1 $ 67 $ 1 $ 0 $ 0 Japan government and Yen-denominated 3,604 140 3,604 140 0 0 Municipalities: U.S. dollar-denominated 515 8 515 8 0 0 Yen-denominated 148 9 148 9 0 0 Mortgage- and asset- U.S. dollar-denominated 74 1 74 1 0 0 Public utilities: U.S. dollar-denominated 1,585 105 892 48 693 57 Yen-denominated 604 12 604 12 0 0 Banks/financial institutions: U.S. dollar-denominated 625 35 340 19 285 16 Yen-denominated 3,057 258 3,057 258 0 0 Other corporate: U.S. dollar-denominated 12,899 1,109 5,782 407 7,117 702 Yen-denominated 1,306 82 1,306 82 0 0 Total $ 24,484 $ 1,760 $ 16,389 $ 985 $ 8,095 $ 775
Composition of Commercial Mortgage and Other Loans	The following table reflects the composition of commercial mortgage and other loans by portfolio segment as of the periods presented. (In millions) March 31, 2019 December 31, 2018 Commercial mortgage and other loans: Transitional real estate loans $ 4,398 $ 4,394 Commercial mortgage loans 1,085 1,065 Middle market loans 1,726 1,487 Total gross commercial mortgage and other loans 7,209 6,946 Valuation allowance (29 ) (27 ) Total net commercial mortgage and other loans $ 7,180 $ 6,919
Allowance for Loan Losses by Portfolio Segment	The following table presents the rollforward of the allowance for loan losses by portfolio segment during the three -month period ended March 31 . (In millions) Commercial Mortgage Loans Transitional Real Estate Loans Middle Market Loans Total Allowance for loan losses at December 31, 2018 $ (1 ) $ (17 ) $ (9 ) $ (27 ) Addition to (release of) allowance for credit losses 0 (1 ) (1 ) (2 ) Allowance for loan losses at March 31, 2019 $ (1 ) $ (18 ) $ (10 ) $ (29 )
Other Investments	The table below reflects the composition of the carrying value for other investments as of the periods presented. (In millions) March 31, 2019 December 31, 2018 Other investments: Policy loans $ 236 $ 232 Short-term investments (1) 543 152 Limited partnerships 434 377 Other 25 26 Total other investments $ 1,238 $ 787 (1)
Securities Lending Transactions Accounted for as Secured Borrowings	Details of collateral by loaned security type and remaining maturity of the agreements were as follows: Securities Lending Transactions Accounted for as Secured Borrowings March 31, 2019 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Greater Total Securities lending transactions: Fixed maturity securities: Japan government and agencies $ 0 $ 1,101 $ 1,901 $ 3,002 Public utilities 15 0 0 15 Banks/financial institutions 74 0 0 74 Other corporate 764 0 0 764 Equity securities 15 0 0 15 Total borrowings $ 868 $ 1,101 $ 1,901 $ 3,870 Gross amount of recognized liabilities for securities lending transactions $ 1,969 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 1,901 (1) The related loaned security, under the Company's U.S. securities lending program, can be returned to the Company at the transferee's discretion; therefore, they are classified as Overnight and Continuous. Securities Lending Transactions Accounted for as Secured Borrowings December 31, 2018 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Greater Total Securities lending transactions: Fixed maturity securities: Japan government and agencies $ 0 $ 387 $ 1,190 $ 1,577 Municipalities 5 0 0 5 Public utilities 27 0 0 27 Banks/financial institutions 74 0 0 74 Other corporate 549 0 0 549 Equity securities 10 0 0 10 Total borrowings $ 665 $ 387 $ 1,190 $ 2,242 Gross amount of recognized liabilities for securities lending transactions $ 1,052 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 1,190 (1) The related loaned security, under the Company's U.S. securities lending program, can be returned to the Company at the transferee's discretion; therefore, they are classified as Overnight and Continuous
Variable Interest Entity, Consolidated
Investments in Variable Interest Entities	VIEs - Consolidated The following table presents the cost or amortized cost, fair value and balance sheet caption in which the assets and liabilities of consolidated VIEs are reported. Investments in Consolidated Variable Interest Entities March 31, 2019 December 31, 2018 (In millions) Cost or Amortized Fair Cost or Amortized Fair Assets: Fixed maturity securities, available for sale $ 3,756 $ 4,543 $ 3,849 $ 4,466 Equity securities 180 180 160 160 Commercial mortgage and other loans 5,892 5,894 5,528 5,506 Other investments (1) 374 374 328 328 Other assets (2) 178 178 182 182 Total assets of consolidated VIEs $ 10,380 $ 11,169 $ 10,047 $ 10,642 Liabilities: Other liabilities (2) $ 108 $ 108 $ 102 $ 102 Total liabilities of consolidated VIEs $ 108 $ 108 $ 102 $ 102 (1) Consists entirely of alternative investments in limited partnerships (2)
Variable Interest Entity, Not Consolidated
Investments in Variable Interest Entities	VIEs - Not Consolidated The table below reflects the amortized cost, fair value and balance sheet caption in which the Company's investment in VIEs not consolidated are reported. Investments in Variable Interest Entities Not Consolidated March 31, 2019 December 31, 2018 (In millions) Amortized Fair Amortized Fair Assets: Fixed maturity securities, available for sale $ 4,455 $ 5,025 $ 4,575 $ 4,982 Fixed maturity securities, held to maturity 2,006 2,331 2,007 2,254 Other investments (1) 59 59 49 49 Total investments in VIEs not consolidated $ 6,520 $ 7,415 $ 6,631 $ 7,285 (1)

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	March 31, 2019 December 31, 2018 (In millions) Asset Liability Asset Liability Hedge Designation/ Derivative Notional Fair Value Fair Value Notional Fair Value Fair Value Cash flow hedges: Foreign currency swaps - VIE $ 75 $ 0 $ 6 $ 75 $ 1 $ 4 Total cash flow hedges 75 0 6 75 1 4 Fair value hedges: Foreign currency forwards 691 0 24 2,086 0 34 Foreign currency options 10,887 0 2 9,070 3 1 Interest rate swaptions 1,500 0 1 500 0 1 Total fair value hedges 13,079 0 27 11,656 3 36 Non-qualifying strategies: Foreign currency swaps 2,800 96 98 2,800 103 129 Foreign currency swaps - VIE 2,587 178 102 2,587 181 101 Foreign currency forwards 15,208 119 132 16,057 126 117 Foreign currency options 552 0 0 430 0 0 Interest rate swaps 4,750 8 0 4,750 3 0 Total non-qualifying strategies 25,897 401 332 26,624 413 347 Total derivatives $ 39,051 $ 401 $ 365 $ 38,355 $ 417 $ 387
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following table presents the gains and losses on derivatives and the related hedged items in fair value hedges. Fair Value Hedging Relationships (In millions) Hedging Derivatives Hedged Items Hedging Derivatives Hedged Items Total Gains (Losses) (1) Gains (Losses) (2) Gains (Losses) (2) Net Realized Gains (Losses) Recognized for Fair Value Hedge Three Months Ended March 31, 2019: Foreign currency Fixed maturity securities $ 9 $ (10 ) $ 19 $ (18 ) $ 1 Foreign currency Fixed maturity securities (4 ) (4 ) 0 0 0 Interest rate Fixed maturity securities (1 ) (1 ) 0 0 0 Total gains (losses) $ 4 $ (15 ) $ 19 $ (18 ) $ 1 Three Months Ended March 31, 2018: Foreign currency forwards Fixed maturity securities $ 414 $ (39 ) $ 453 $ (464 ) $ (11 ) Foreign currency options Fixed maturity securities (1 ) (1 ) 0 0 0 Total gains (losses) $ 413 $ (40 ) $ 453 $ (464 ) $ (11 ) (1) Gains (losses) excluded from effectiveness testing includes the forward point on foreign currency forwards and time value change on foreign currency options which are reported in the consolidated statement of earnings as realized investment gains (losses). It also includes the change in the fair value of the interest rate swaptions related to the time value of the swaptions which is recognized as a component of other comprehensive income (loss). (2) Gains and losses on foreign currency forwards and options and related hedged items are reported in the consolidated statement of earnings as realized investment gains (losses). For interest rate swaptions and related hedged items, gains and losses included in the hedge assessment are reported within net investment income. For the three -month period ended March 31, 2019
Schedule of Interest Rate Fair Value Hedges Hedged Items	The following table shows the carrying amounts of assets designated and qualifying as hedged items in fair value hedges of interest rate risk and the related cumulative hedge adjustment included in the carrying amount. (In millions) Carrying Amount of the Hedged Assets/(Liabilities) (1) Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of Hedged Assets/(Liabilities) March 31, 2019 December 31, 2018 March 31, 2019 December 31, 2018 Fixed maturity securities $ 5,285 $ 6,593 $ 276 $ 294 (1) The balance includes hedging adjustment on discontinued hedging relationships of $276 in 2019 and $294 in 2018. The total notional amount of the Company's interest rate swaptions was $1,500 in 2019 and $500
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following table summarizes the impact to realized investment gains (losses) and other comprehensive income (loss) from all derivatives and hedging instruments. Three Months Ended March 31, 2019 2018 (In millions) Net Investment Income Loss (1) Realized Investment Other (2) Net Investment Income Loss (1) Realized Investment Other (2) Qualifying hedges: Cash flow hedges: Foreign currency swaps - VIE $ (1 ) $ 0 $ (2 ) $ 0 $ 1 $ 6 Total cash flow hedges (1 ) 0 (3 ) (2 ) 0 1 (3 ) 6 Fair value hedges: Foreign currency forwards (4) (9 ) (50 ) Foreign currency options (4) (4 ) (1 ) Interest rate swaptions (4) 0 0 (1 ) 0 0 0 Total fair value hedges 0 (13 ) (1 ) 0 (51 ) 0 Net investment hedge: Non-derivative hedging instruments 0 0 0 (84 ) Foreign currency options 0 0 0 (8 ) Total net investment hedge 0 0 0 (92 ) Non-qualifying strategies: Foreign currency swaps 44 (110 ) Foreign currency swaps - VIE (16 ) 124 Foreign currency forwards (21 ) 179 Foreign currency options 0 1 Interest rate swaps 6 0 Total non-qualifying strategies 13 194 Total $ (1 ) $ 0 $ (3 ) $ 0 $ 144 $ (86 ) (1) Net investment income (loss) includes net interest on swaps. (2) Cash flow hedge items and the change in the fair value of interest rate swaptions related to the time value of the swaptions in fair value hedges are recorded as unrealized gains (losses) on derivatives and net investment hedge items are recorded in the unrealized foreign currency translation gains (losses) line in the consolidated statement of comprehensive income (loss). (3) Impact of cash flow hedges reported as realized investment gains (losses) includes an immaterial amount of gains or losses reclassified from accumulated other comprehensive income (loss) into earnings. It also includes an immaterial amount excluded from effectiveness testing during the three-month periods ended March 31, 2019 and 2018 , respectively. (4)
Offsetting Assets	Offsetting of Financial Assets and Derivative Asset March 31, 2019 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Assets Gross Amount Offset in Balance Sheet Net Amount of Assets Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Received Net Amount Derivative assets: Derivative assets subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 215 $ 0 $ 215 $ (118 ) $ (10 ) $ (80 ) $ 7 OTC - cleared 8 0 8 0 0 (1 ) 7 Total derivative assets subject to a master netting agreement or offsetting arrangement 223 0 223 (118 ) (10 ) (81 ) 14 Derivative assets not subject to a master netting agreement or offsetting arrangement OTC - bilateral 178 178 178 Total derivative assets not subject to a master netting agreement or offsetting arrangement 178 178 178 Total derivative assets 401 0 401 (118 ) (10 ) (81 ) 192 Securities lending and similar arrangements 1,959 0 1,959 0 0 (1,959 ) 0 Total $ 2,360 $ 0 $ 2,360 $ (118 ) $ (10 ) $ (2,040 ) $ 192 December 31, 2018 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Assets Gross Amount Offset in Balance Sheet Net Amount of Assets Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Received Net Amount Derivative assets: Derivative assets subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 231 $ 0 $ 231 $ (152 ) $ (23 ) $ (55 ) $ 1 OTC - cleared 3 0 3 0 0 (3 ) 0 Total derivative assets subject to a master netting agreement or offsetting arrangement 234 0 234 (152 ) (23 ) (58 ) 1 Derivative assets not subject to a master netting agreement or offsetting arrangement OTC - bilateral 183 183 183 Total derivative assets not subject to a master netting agreement or offsetting arrangement 183 183 183 Total derivative assets 417 0 417 (152 ) (23 ) (58 ) 184 Securities lending and similar arrangements 1,029 0 1,029 0 0 (1,029 ) 0 Total $ 1,446 $ 0 $ 1,446 $ (152 ) $ (23 ) $ (1,087 ) $ 184
Offsetting Liabilities	Offsetting of Financial Liabilities and Derivative Liabilities March 31, 2019 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Liabilities Gross Amount Offset in Balance Sheet Net Amount of Liabilities Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Pledged Net Amount Derivative liabilities: Derivative liabilities subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 257 $ 0 $ 257 $ (118 ) $ (65 ) $ (45 ) $ 29 Total derivative liabilities subject to a master netting agreement or offsetting arrangement 257 0 257 (118 ) (65 ) (45 ) 29 Derivative liabilities not subject to a master netting agreement or offsetting arrangement OTC - bilateral 108 108 108 Total derivative liabilities not subject to a master netting agreement or offsetting arrangement 108 108 108 Total derivative liabilities 365 0 365 (118 ) (65 ) (45 ) 137 Securities lending and similar arrangements 1,969 0 1,969 (1,959 ) 0 0 10 Total $ 2,334 $ 0 $ 2,334 $ (2,077 ) $ (65 ) $ (45 ) $ 147 December 31, 2018 Gross Amounts Not Offset (In millions) Gross Amount of Recognized Liabilities Gross Amount Offset in Balance Sheet Net Amount of Liabilities Presented in Balance Sheet Financial Instruments Securities Collateral Cash Collateral Pledged Net Amount Derivative liabilities: Derivative liabilities subject to a master netting agreement or offsetting arrangement OTC - bilateral $ 285 $ 0 $ 285 $ (152 ) $ (37 ) $ (68 ) $ 28 Total derivative liabilities subject to a master netting agreement or offsetting arrangement 285 0 285 (152 ) (37 ) (68 ) 28 Derivative liabilities not subject to a master netting agreement or offsetting arrangement OTC - bilateral 102 102 102 Total derivative liabilities not subject to a master netting agreement or offsetting arrangement 102 102 102 Total derivative liabilities 387 0 387 (152 ) (37 ) (68 ) 130 Securities lending and similar arrangements 1,052 0 1,052 (1,029 ) 0 0 23 Total $ 1,439 $ 0 $ 1,439 $ (1,181 ) $ (37 ) $ (68 ) $ 153

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Hierarchy, Assets and Liabilities Measured on Recurring Basis	The following tables present the fair value hierarchy levels of the Company's assets and liabilities that are measured and carried at fair value on a recurring basis. March 31, 2019 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturity securities: Government and agencies $ 34,727 $ 1,522 $ 0 $ 36,249 Municipalities 0 1,908 0 1,908 Mortgage- and asset-backed securities 0 236 178 414 Public utilities 0 6,412 85 6,497 Sovereign and supranational 0 1,154 0 1,154 Banks/financial institutions 0 9,368 23 9,391 Other corporate 0 32,027 284 32,311 Total fixed maturity securities 34,727 52,627 570 87,924 Equity securities 925 70 46 1,041 Other investments 543 0 0 543 Cash and cash equivalents 3,892 0 0 3,892 Other assets: Foreign currency swaps 0 96 178 274 Foreign currency forwards 0 119 0 119 Interest rate swaps 0 8 0 8 Total other assets 0 223 178 401 Total assets $ 40,087 $ 52,920 $ 794 $ 93,801 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 98 $ 108 $ 206 Foreign currency forwards 0 156 0 156 Foreign currency options 0 2 0 2 Interest rate swaptions 0 1 0 1 Total liabilities $ 0 $ 257 $ 108 $ 365 December 31, 2018 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturity securities: Government and agencies $ 32,993 $ 1,349 $ 0 $ 34,342 Municipalities 0 1,863 0 1,863 Mortgage- and asset-backed securities 0 162 177 339 Public utilities 0 7,062 109 7,171 Sovereign and supranational 0 1,260 0 1,260 Banks/financial institutions 0 8,895 23 8,918 Other corporate 0 28,789 213 29,002 Total fixed maturity securities 32,993 49,380 522 82,895 Equity securities 874 67 46 987 Other investments 152 0 0 152 Cash and cash equivalents 4,337 0 0 4,337 Other assets: Foreign currency swaps 0 103 182 285 Foreign currency forwards 0 126 0 126 Foreign currency options 0 3 0 3 Interest rate swaps 0 3 0 3 Total other assets 0 235 182 417 Total assets $ 38,356 $ 49,682 $ 750 $ 88,788 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 132 $ 102 $ 234 Foreign currency forwards 0 151 0 151 Foreign currency options 0 1 0 1 Interest rate swaptions 0 1 0 1 Total liabilities $ 0 $ 285 $ 102 $ 387
Fair Value Hierarchy Levels of Assets and Liabilities Carried at Cost or Amortized Cost	The following tables present the carrying amount and fair value categorized by fair value hierarchy level for the Company's financial instruments that are not carried at fair value. March 31, 2019 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturity securities: Government and agencies $ 21,961 $ 27,629 $ 350 $ 0 $ 27,979 Municipalities 814 0 1,061 0 1,061 Mortgage and asset-backed 20 0 8 13 21 Public utilities 2,728 0 3,068 0 3,068 Sovereign and 1,154 0 1,332 0 1,332 Banks/financial institutions 949 0 1,039 0 1,039 Other corporate 2,537 0 2,946 0 2,946 Commercial mortgage and 7,180 0 0 7,185 7,185 Other investments (1) 25 0 25 0 25 Total assets $ 37,368 $ 27,629 $ 9,829 $ 7,198 $ 44,656 Liabilities: Other policyholders’ funds $ 7,185 $ 0 $ 0 $ 7,110 $ 7,110 Notes payable 5,766 0 5,809 270 6,079 Total liabilities $ 12,951 $ 0 $ 5,809 $ 7,380 $ 13,189 (1) Excludes policy loans of $236 and equity method investments of $434 , at carrying value December 31, 2018 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturity securities: Government and agencies $ 21,712 $ 27,030 $ 8 $ 0 $ 27,038 Municipalities 359 0 469 0 469 Mortgage and asset-backed 14 0 0 15 15 Public utilities 2,727 0 2,973 0 2,973 Sovereign and 1,551 0 1,840 0 1,840 Banks/financial institutions 1,445 0 1,583 0 1,583 Other corporate 2,510 0 2,804 0 2,804 Commercial mortgage and 6,919 0 0 6,893 6,893 Other investments (1) 26 0 26 0 26 Total assets $ 37,263 $ 27,030 $ 9,703 $ 6,908 $ 43,641 Liabilities: Other policyholders’ funds $ 7,146 $ 0 $ 0 $ 7,067 $ 7,067 Notes payable 5,765 0 5,606 270 5,876 Total liabilities $ 12,911 $ 0 $ 5,606 $ 7,337 $ 12,943 (1) Excludes policy loans of $232 and equity method investments of $377
Fair Value Assets Securities Carried At Fair Value Primary Pricing Sources	December 31, 2018 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities available for sale, carried at fair value: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 32,993 $ 1,349 $ 0 $ 34,342 Total government and agencies 32,993 1,349 0 34,342 Municipalities: Third party pricing vendor 0 1,863 0 1,863 Total municipalities 0 1,863 0 1,863 Mortgage- and asset-backed securities: Third party pricing vendor 0 162 0 162 Broker/other 0 0 177 177 Total mortgage- and asset-backed securities 0 162 177 339 Public utilities: Third party pricing vendor 0 7,062 0 7,062 Broker/other 0 0 109 109 Total public utilities 0 7,062 109 7,171 Sovereign and supranational: Third party pricing vendor 0 1,260 0 1,260 Total sovereign and supranational 0 1,260 0 1,260 Banks/financial institutions: Third party pricing vendor 0 8,895 0 8,895 Broker/other 0 0 23 23 Total banks/financial institutions 0 8,895 23 8,918 Other corporate: Third party pricing vendor 0 28,789 0 28,789 Broker/other 0 0 213 213 Total other corporate 0 28,789 213 29,002 Total securities available for sale $ 32,993 $ 49,380 $ 522 $ 82,895 Equity securities, carried at fair value: Third party pricing vendor $ 874 $ 67 $ 0 $ 941 Broker/other 0 0 46 46 Total equity securities $ 874 $ 67 $ 46 $ 987 March 31, 2019 (In millions) Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Total Securities available for sale, carried at fair value: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 34,727 $ 1,522 $ 0 $ 36,249 Total government and agencies 34,727 1,522 0 36,249 Municipalities: Third party pricing vendor 0 1,908 0 1,908 Total municipalities 0 1,908 0 1,908 Mortgage- and asset-backed securities: Third party pricing vendor 0 236 0 236 Broker/other 0 0 178 178 Total mortgage- and asset-backed securities 0 236 178 414 Public utilities: Third party pricing vendor 0 6,412 0 6,412 Broker/other 0 0 85 85 Total public utilities 0 6,412 85 6,497 Sovereign and supranational: Third party pricing vendor 0 1,154 0 1,154 Total sovereign and supranational 0 1,154 0 1,154 Banks/financial institutions: Third party pricing vendor 0 9,323 0 9,323 Broker/other 0 45 23 68 Total banks/financial institutions 0 9,368 23 9,391 Other corporate: Third party pricing vendor 0 31,964 0 31,964 Broker/other 0 63 284 347 Total other corporate 0 32,027 284 32,311 Total securities available for sale $ 34,727 $ 52,627 $ 570 $ 87,924 Equity securities, carried at fair value: Third party pricing vendor $ 925 $ 70 $ 0 $ 995 Broker/other 0 0 46 46 Total equity securities $ 925 $ 70 $ 46 $ 1,041
Fair Value Assets Held-To-Maturity Securities Primary Pricing Sources	March 31, 2019 (In millions) Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Total Securities held to maturity, carried at amortized cost: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 27,629 $ 350 $ 0 $ 27,979 Total government and agencies 27,629 350 0 27,979 Municipalities: Third party pricing vendor 0 1,061 0 1,061 Total municipalities 0 1,061 0 1,061 Mortgage- and asset-backed securities: Third party pricing vendor 0 8 0 8 Broker/other 0 0 13 13 Total mortgage- and asset-backed securities 0 8 13 21 Public utilities: Third party pricing vendor 0 3,068 0 3,068 Total public utilities 0 3,068 0 3,068 Sovereign and supranational: Third party pricing vendor 0 1,332 0 1,332 Total sovereign and supranational 0 1,332 0 1,332 Banks/financial institutions: Third party pricing vendor 0 1,039 0 1,039 Total banks/financial institutions 0 1,039 0 1,039 Other corporate: Third party pricing vendor 0 2,946 0 2,946 Total other corporate 0 2,946 0 2,946 Total securities held to maturity $ 27,629 $ 9,804 $ 13 $ 37,446 December 31, 2018 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities held to maturity, carried at amortized cost: Fixed maturity securities: Government and agencies: Third party pricing vendor $ 27,030 $ 8 $ 0 $ 27,038 Total government and agencies 27,030 8 0 27,038 Municipalities: Third party pricing vendor 0 469 0 469 Total municipalities 0 469 0 469 Mortgage- and asset-backed securities: Broker/other 0 0 15 15 Total mortgage- and asset-backed securities 0 0 15 15 Public utilities: Third party pricing vendor 0 2,973 0 2,973 Total public utilities 0 2,973 0 2,973 Sovereign and supranational: Third party pricing vendor 0 1,840 0 1,840 Total sovereign and supranational 0 1,840 0 1,840 Banks/financial institutions: Third party pricing vendor 0 1,583 0 1,583 Total banks/financial institutions 0 1,583 0 1,583 Other corporate: Third party pricing vendor 0 2,804 0 2,804 Total other corporate 0 2,804 0 2,804 Total securities held to maturity $ 27,030 $ 9,677 $ 15 $ 36,722
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following tables present the changes in fair value of the Company's investments and derivatives carried at fair value classified as Level 3. Three Months Ended Fixed Maturity Securities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 177 $ 109 $ 23 $ 213 $ 46 $ 80 $ 0 $ 648 Realized investment gains (losses) included 0 0 0 0 0 (8 ) 0 (8 ) Unrealized gains (losses) included in other 1 1 0 1 0 (2 ) 0 1 Purchases, issuances, sales and settlements: Purchases 0 0 0 63 0 0 0 63 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 (2 ) 0 0 0 (2 ) Settlements 0 0 0 0 0 0 0 0 Transfers into Level 3 0 0 0 25 (2) 0 0 0 25 Transfers out of Level 3 0 (25 ) (2) 0 (16 ) (3) 0 0 0 (41 ) Balance, end of period $ 178 $ 85 $ 23 $ 284 $ 46 $ 70 $ 0 $ 686 Changes in unrealized gains (losses) relating earnings $ 0 $ 0 $ 0 $ 0 $ 0 $ (8 ) $ 0 $ (8 ) (1) Derivative assets and liabilities are presented net (2) Transfer due to sector classification change (3) Transfer due to availability of observable market inputs Three Months Ended Fixed Maturity Securities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 175 $ 68 $ 25 $ 146 $ 16 $ 22 $ 1 $ 453 Realized investment gains (losses) included in earnings 0 0 0 0 0 126 0 126 Unrealized gains (losses) included in other comprehensive income (loss) 11 (1 ) (1 ) (2 ) 0 6 0 13 Purchases, issuances, sales and settlements: Purchases 0 16 0 0 0 0 0 16 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 0 0 0 0 0 Settlements 0 0 0 (1 ) 0 0 0 (1 ) Transfers into Level 3 0 0 0 0 0 0 0 0 Transfers out of Level 3 0 0 0 0 0 0 0 0 Balance, end of period $ 186 $ 83 $ 24 $ 143 $ 16 $ 154 $ 1 $ 607 Changes in unrealized gains (losses) relating earnings $ 0 $ 0 $ 0 $ 0 $ 0 $ 126 $ 0 $ 126 (1)
Fair Value Measurement Inputs and Valuation Techniques	Level 3 Significant Unobservable Input Sensitivity The following tables summarize the significant unobservable inputs used in the valuation of the Company's Level 3 investments and derivatives carried at fair value. Included in the tables are the inputs or range of possible inputs that have an effect on the overall valuation of the financial instruments. March 31, 2019 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturity securities: Mortgage- and asset-backed securities $ 178 Consensus pricing Offered quotes N/A (a) Public utilities 85 Discounted cash flow Credit spreads N/A (a) Banks/financial institutions 23 Consensus pricing Offered quotes N/A (a) Other corporate 284 Discounted cash flow Credit spreads N/A (a) Equity securities 46 Net asset value Offered quotes N/A (a) Other assets: Foreign currency swaps 117 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) CDS spreads 13 - 109 bps 61 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) Total assets $ 794 Liabilities: Other liabilities: Foreign currency swaps $ 102 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) CDS spreads 30 - 187 bps 6 Discounted cash flow Interest rates (USD) 2.48% - 2.66% (b) Interest rates (JPY) .13% - .57% (c) Total liabilities $ 108 (a) N/A represents securities where the Company receives unadjusted broker quotes and for which there is no transparency into the providers' valuation techniques or unobservable inputs. (b) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (c) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps December 31, 2018 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturity securities: Mortgage- and asset-backed securities $ 177 Consensus pricing Offered quotes N/A (a) Public utilities 109 Discounted cash flow Credit spreads N/A (a) Banks/financial institutions 23 Consensus pricing Offered quotes N/A (a) Other corporate 213 Discounted cash flow Credit spreads N/A (a) Equity securities 46 Net asset value Offered quotes N/A (a) Other assets: Foreign currency swaps 125 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) CDS spreads 19 - 120 bps 57 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) Total assets $ 750 Liabilities: Other liabilities: Foreign currency swaps $ 98 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) CDS spreads 28 - 211 bps 4 Discounted cash flow Interest rates (USD) 2.75% - 2.84% (b) Interest rates (JPY) .18% - .71% (c) Total liabilities $ 102 (a) N/A represents securities where the Company receives unadjusted broker quotes and for which there is no transparency into the providers' valuation techniques or unobservable inputs. (b) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps

POLICY LIABILITIES (Tables)

POLICY LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2019
Insurance Loss Reserves [Abstract]
Schedule of Liability for Unpaid Claims Adjustment Expense	Changes in the liability for unpaid policy claims were as follows: Three Months Ended (In millions) 2019 2018 Unpaid supplemental health claims, beginning of period $ 3,952 $ 3,884 Less reinsurance recoverables 29 30 Net balance, beginning of period 3,923 3,854 Add claims incurred during the period related to: Current year 1,825 1,842 Prior years (167 ) (192 ) Total incurred 1,658 1,650 Less claims paid during the period on claims incurred during: Current year 506 518 Prior years 1,137 1,116 Total paid 1,643 1,634 Effect of foreign exchange rate changes on unpaid claims 0 142 Net balance, end of period 3,938 4,012 Add reinsurance recoverables 29 31 Unpaid supplemental health claims, end of period 3,967 4,043 Unpaid life claims, end of period 658 587 Total liability for unpaid policy claims $ 4,625 $ 4,630

REINSURANCE (Tables)

REINSURANCE (Tables)	3 Months Ended
	Mar. 31, 2019
Reinsurance Disclosures [Abstract]
Effects of Reinsurance	The following table reconciles direct premium income and direct benefits and claims to net amounts after the effect of reinsurance. Three Months Ended (In millions) 2019 2018 Direct premium income $ 4,776 $ 4,833 Ceded to other companies: Ceded Aflac Japan closed blocks (121 ) (129 ) Other (15 ) (15 ) Assumed from other companies: Retrocession activities 50 54 Other 1 2 Net premium income $ 4,691 $ 4,745 Direct benefits and claims $ 3,041 $ 3,119 Ceded benefits and change in reserves for future benefits: Ceded Aflac Japan closed blocks (111 ) (117 ) Eliminations 10 12 Other (11 ) (12 ) Assumed from other companies: Retrocession activities 48 52 Eliminations (10 ) (12 ) Benefits and claims, net $ 2,967 $ 3,042

NOTES PAYABLE AND LEASE OBLIG_2

NOTES PAYABLE AND LEASE OBLIGATIONS (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	A summary of notes payable and lease obligations follows: (In millions) March 31, 2019 December 31, 2018 4.00% senior notes due February 2022 $ 348 $ 348 3.625% senior notes due June 2023 698 698 3.625% senior notes due November 2024 746 746 3.25% senior notes due March 2025 448 447 2.875% senior notes due October 2026 297 297 6.90% senior notes due December 2039 220 220 6.45% senior notes due August 2040 254 254 4.00% senior notes due October 2046 394 394 4.750% senior notes due January 2049 540 540 Yen-denominated senior notes and subordinated debentures: .932% senior notes due January 2027 (principal amount 60.0 billion yen) 538 538 1.159% senior notes due October 2030 (principal amount 29.3 billion yen) 262 262 1.488% senior notes due October 2033 (principal amount 15.2 billion yen) 136 136 1.750% senior notes due October 2038 (principal amount 8.9 billion yen) 79 79 2.108% subordinated debentures due October 2047 (principal amount 60.0 billion yen) 536 536 Yen-denominated loans: Variable interest rate loan due September 2021 (.32% in 2019 and 2018, principal amount 5.0 billion yen) 45 45 Variable interest rate loan due September 2023 (.47% in 2019 and 2018, principal amount 25.0 billion yen) 225 225 Finance lease obligations payable through 2025 12 13 Operating lease obligations payable through 2028 (1) 122 0 Total notes payable and lease obligations $ 5,900 $ 5,778 (1) See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2019 related to leases.
Schedule of Lease Maturities	The following table presents the contractual maturities and present value of lease liabilities. March 31, 2019 (In millions) Operating Leases Finance Leases Total 2019 $ 33 $ 3 $ 36 2020 30 3 33 2021 20 2 22 2022 17 2 19 2023 9 1 10 After 2023 24 1 25 Total lease payments $ 133 $ 12 $ 145 Less: Interest $ 11 $ 0 $ 11 Present value of lease liabilities $ 122 $ 12 $ 134
Lease, Cost	The following table presents the weighted average remaining lease term and weighted average discount rate for lease liabilities. March 31, 2019 Weighted average remaining lease term (years): Operating leases 4.4 Finance leases 3.8 Weighted average discount rate: Operating leases 2.55 % Finance leases 1.56 %
Schedule of Line of Credit Facilities	A summary of the Company's lines of credit as of March 31, 2019 follows: Borrower Type Term Expiration Date Capacity Amount Outstanding Interest Rate on Borrowed Amount Maturity Period Commitment Fee Business Purpose Aflac Incorporated uncommitted bilateral 364 days December 27, 2019 $100 million $0 million The rate quoted by the bank and agreed upon at the time of borrowing Up to 3 months None General corporate purposes Aflac Incorporated unsecured revolving 5 years March 29, 2024, or the date commitments are terminated pursuant to an event of default 100.0 billion yen 0.0 billion yen A rate per annum equal to (a) Tokyo interbank market rate (TIBOR) plus, the alternative applicable TIBOR margin during the availability period from the closing date to the commitment termination date or (b) the TIBOR rate offered by the agent to major banks in yen for the applicable period plus, the applicable alternative TIBOR margin during the term out period No later than .30% to .50%, depending on the Parent Company's debt ratings as of the date of determination General corporate purposes, including a capital contingency plan for the operations of the Parent Company Aflac Incorporated unsecured revolving 5 years April 4, 2023, or the date commitments are terminated pursuant to an event of default 55.0 billion yen, or the equivalent amount in U.S. dollars 0.0 billion yen A rate per annum equal to, at the Company's option, either, (a) London Interbank Offered Rate (LIBOR) adjusted for certain costs or (b) a base rate determined by reference to the highest of (1) the federal funds rate plus 1/2 of 1%, (2) the rate of interest for such day announced by Mizuho Bank, Ltd. as its prime rate, or (3) the eurocurrency rate for an interest period of one month plus 1.00%, in each case plus an applicable margin No later than April 4, 2023 .085% to .225%, depending on the Parent Company's debt ratings as of the date of determination General corporate purposes, including a capital contingency plan for the operations of the Parent Company Aflac Incorporated uncommitted bilateral None specified None specified $50 million $0 million A rate per annum equal to, at the Parent Company's option, either (a) a eurocurrency rate determined by reference to the agent's LIBOR for the interest period relevant to such borrowing or (b) the base rate determined by reference to the greater of (i) the prime rate as determined by the agent, and (ii) the sum of 0.50% and the federal funds rate for such day Up to 3 months None General corporate purposes Aflac (1) uncommitted revolving 364 days November 29, 2019 $250 million $0 million USD three-month LIBOR plus 75 basis points per annum 3 months None General corporate purposes Aflac Incorporated (1) uncommitted revolving 364 days April 2, 2019 (2) 50.0 billion yen 0.0 billion yen Three-month TIBOR plus 80 basis points per annum 3 months None General corporate purposes (1) Intercompany credit agreement (2) Renewed in April 2019 with an expiration date of April 2, 2020

SHAREHOLDERS' EQUITY (Tables)

SHAREHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Outstanding Roll Forward	The following table is a reconciliation of the number of shares of the Company's common stock for the three -month periods ended March 31 . (In thousands of shares) 2019 2018 Common stock - issued: Balance, beginning of period 1,347,540 1,345,762 Exercise of stock options and issuance of restricted shares 1,060 1,014 Balance, end of period 1,348,600 1,346,776 Treasury stock: Balance, beginning of period 592,254 564,852 Purchases of treasury stock: Open market 10,237 6,640 Other 561 315 Dispositions of treasury stock: Shares issued to AFL Stock Plan (430 ) (384 ) Exercise of stock options (231 ) (305 ) Other (278 ) (99 ) Balance, end of period 602,113 571,019 Shares outstanding, end of period 746,487 775,757
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table presents the approximate number of share-based awards to purchase shares, on a weighted-average basis, that were considered to be anti-dilutive and were excluded from the calculation of diluted earnings per share for the following periods. Three Months Ended (In thousands) 2019 2018 Anti-dilutive share-based awards 22 9
Schedule of Accumulated Other Comprehensive Income (Loss)	Reclassifications from Accumulated Other Comprehensive Income The tables below are reconciliations of accumulated other comprehensive income by component for the following periods. Changes in Accumulated Other Comprehensive Income Three Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Total Balance, beginning of period $ (1,847 ) $ 4,234 $ (24 ) $ (212 ) $ 2,151 Other comprehensive (1 ) 2,340 (2 ) 3 2,340 Amounts reclassified from 0 (13 ) 0 3 (10 ) Net current-period other (1 ) 2,327 (2 ) 6 2,330 Balance, end of period $ (1,848 ) $ 6,561 $ (26 ) $ (206 ) $ 4,481 All amounts in the table above are net of tax. Three Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Liability Adjustment Total Balance, beginning of period $ (1,750 ) $ 5,964 $ (23 ) $ (163 ) $ 4,028 Other comprehensive 447 (983 ) 2 (37 ) (571 ) Amounts reclassified from 0 225 (1) 0 3 228 Net current-period other 447 (758 ) 2 (34 ) (343 ) Balance, end of period $ (1,303 ) $ 5,206 $ (21 ) $ (197 ) $ 3,685 (1) Includes amounts reclassified due to changes in accounting principles of $(148) related to financial instruments and $374 related to tax effects from tax reform
Reclassification Out Of Accumulated Other Comprehensive Income	The tables below summarize the amounts reclassified from each component of accumulated other comprehensive income into net earnings for the following periods. Reclassifications Out of Accumulated Other Comprehensive Income (In millions) Three Months Ended Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Unrealized gains (losses) on available-for-sale $ 0 Other-than-temporary impairment 17 Other gains (losses) 17 Total before tax (4 ) Tax (expense) or benefit (1) $ 13 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (4 ) Acquisition and operating expenses (2) Prior service (cost) credit 0 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (3 ) Net of tax Total reclassifications for the period $ 10 Net of tax (1) Based on 25% blended tax rate (2) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 11 for additional details). (In millions) Three Months Ended Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Unrealized gains (losses) on available-for-sale $ 0 Other-than-temporary impairment 2 Other gains (losses) 2 Total before tax (1 ) Tax (expense) or benefit (1) $ 1 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (4 ) Acquisition and operating expenses (2) Prior service (cost) credit 0 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (3 ) Net of tax Total reclassifications for the period $ (2 ) Net of tax (1) Based on 27% blended tax rate (2)

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Options Outstanding and Exercisable	The following table provides information on stock options outstanding and exercisable at March 31, 2019 . Stock Weighted-Average Aggregate Weighted-Average Outstanding 4,558 5.0 $ 94 $ 29.36 Exercisable 4,097 4.6 88 28.54
Schedule of Nonvested Restricted Stock Units Activity	The following table summarizes restricted stock activity during the three -month period ended March 31 . (In thousands of shares) Shares Weighted-Average Grant-Date Fair Value Per Share Restricted stock at December 31, 2018 3,407 $ 36.52 Granted in 2019 940 49.17 Canceled in 2019 (18 ) 37.98 Vested in 2019 (1,732 ) 32.16 Restricted stock at March 31, 2019 2,597 $ 44.02

BENEFIT PLANS (Tables)

BENEFIT PLANS (Tables)	3 Months Ended
	Mar. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Schedule of Net Benefit Costs	Pension and other postretirement benefit expenses are included in acquisition and operating expenses in the consolidated statement of earnings, which includes other components of net periodic pension cost and postretirement costs (other than service costs) of $5 million for both the periods ended March 31, 2019 and 2018 . Total net periodic cost includes the following components: Three Months Ended March 31, Pension Benefits Japan U.S. (In millions) 2019 2018 2019 2018 Components of net periodic Service cost $ 5 $ 5 $ 6 $ 7 Interest cost 1 2 9 9 Expected return on plan (2 ) (2 ) (7 ) (7 ) Amortization of net actuarial 1 0 3 4 Net periodic (benefit) cost $ 5 $ 5 $ 11 $ 13

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Aflac Japan
Significant Accounting Policies [Line Items]
Percentage of the Company's total assets	84.00%			84.00%
Percentage of the Company's total revenues	68.00%	71.00%
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
New accounting pronouncement or change in accounting principle, cumulative effect of change on assets			$ 134
New accounting pronouncement or change in accounting principle, cumulative effect of change on liabilities			$ 134

BUSINESS SEGMENT INFORMATION -

BUSINESS SEGMENT INFORMATION - Operations by Segment - Revenues (Details) $ in Millions		3 Months Ended
		Mar. 31, 2019USD ($)segment	Mar. 31, 2018USD ($)
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of Reportable Insurance Business Segments | segment		2
Net earned premiums		$ 4,691	$ 4,745
Net investment income		878	837
Total adjusted revenues		5,537	5,546
Realized investment gains (losses)	[1],[2],[3]	120	(82)
Total revenues		5,657	5,464
Net interest cash flows from derivatives		(7)
Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		3,180	3,263
Net investment income, less amortized hedge costs		610	588
Other income (loss)		12	12
Total revenues		3,802	3,863
Hedge costs		62	55
Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		1,461	1,427
Net investment income		177	175
Other income (loss)		2	2
Total revenues		1,640	1,604
Corporate and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		95	79
Hedge income		$ 20	$ 2
[1]	Amortized hedge costs of $62 and $55 for the three -month periods ended March 31, 2019 , and 2018
[2]	Amortized hedge income of $20 and $2 for the three -month periods ended March 31, 2019 , and 2018
[3]	Net interest cash flows from derivatives associated with certain investment strategies of $(7) for the three -month period ended March 31, 2019 and an immaterial amount in 2018, respectively, have been reclassified from realized investment gains (losses) and included in adjusted earnings as a component of net investment income.

BUSINESS SEGMENT INFORMATION _2

BUSINESS SEGMENT INFORMATION - Operations by Segment - Pretax Earnings (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		$ 1,139	$ 1,109
Realized investment gains (losses)	[1],[2],[3],[4]	103	(98)
Other income (loss)		0	(29)
Earnings before income taxes		1,242	982
Income taxes applicable to pretax adjusted earnings		291	289
Effect of foreign currency translation on after tax adjusted earnings		(8)	21
Net interest cash flows from derivatives		(7)
Gain (loss) on change in fair value of derivative, interest rate component		17	17
Aflac Japan
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		834	818
Hedge costs		62	55
Aflac U.S.
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		323	337
Corporate and other
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		(18)	(46)
Hedge income		$ 20	$ 2
[1]	A gain of $17 and $17 for the three -month periods ended March 31, 2019 , and 2018
[2]	Amortized hedge costs of $62 and $55 for the three -month periods ended March 31, 2019 , and 2018
[3]	Amortized hedge income of $20 and $2 for the three -month periods ended March 31, 2019 , and 2018
[4]	Net interest cash flows from derivatives associated with certain investment strategies of $(7) for the three -month period ended March 31, 2019

BUSINESS SEGMENT INFORMATION _3

BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 145,679	$ 140,406
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	123,042	118,342
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	19,965	19,100
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 2,672	$ 2,964

INVESTMENTS - Available-for-sal

INVESTMENTS - Available-for-sale Debt Securities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	$ 78,706	$ 76,856
Gross Unrealized Gains	10,026	7,733
Gross Unrealized Losses	808	1,694
Fair Value	87,924	82,895
Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	45,249	44,027
Gross Unrealized Gains	6,763	5,308
Gross Unrealized Losses	164	435
Fair Value	51,848	48,900
Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	33,457	32,829
Gross Unrealized Gains	3,263	2,425
Gross Unrealized Losses	644	1,259
Fair Value	36,076	33,995
Japan government and agencies | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	31,238	30,637
Gross Unrealized Gains	4,813	3,700
Gross Unrealized Losses	2	140
Fair Value	36,049	34,197
Municipalities
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,908	1,863
Municipalities | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	509	385
Gross Unrealized Gains	93	32
Gross Unrealized Losses	3	9
Fair Value	599	408
Municipalities | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	1,204	1,343
Gross Unrealized Gains	105	120
Gross Unrealized Losses	0	8
Fair Value	1,309	1,455
Mortgage- and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	414	339
Mortgage- and asset-backed securities | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	233	155
Gross Unrealized Gains	27	22
Gross Unrealized Losses	0	0
Fair Value	260	177
Mortgage- and asset-backed securities | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	147	155
Gross Unrealized Gains	7	8
Gross Unrealized Losses	0	1
Fair Value	154	162
Public utilities
Debt Securities, Available-for-sale [Line Items]
Fair Value	6,497	7,171
Public utilities | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	1,822	1,732
Gross Unrealized Gains	344	280
Gross Unrealized Losses	0	4
Fair Value	2,166	2,008
Public utilities | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	3,841	4,772
Gross Unrealized Gains	522	496
Gross Unrealized Losses	32	105
Fair Value	4,331	5,163
Sovereign and supranational
Debt Securities, Available-for-sale [Line Items]
Fair Value	1,154	1,260
Sovereign and supranational | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	740	826
Gross Unrealized Gains	65	123
Gross Unrealized Losses	0	0
Fair Value	805	949
Sovereign and supranational | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	276	251
Gross Unrealized Gains	73	60
Gross Unrealized Losses	0	0
Fair Value	349	311
Banks/financial institutions
Debt Securities, Available-for-sale [Line Items]
Fair Value	9,391	8,918
Banks/financial institutions | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	5,664	5,440
Gross Unrealized Gains	597	502
Gross Unrealized Losses	139	238
Fair Value	6,122	5,704
Banks/financial institutions | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	2,798	2,860
Gross Unrealized Gains	484	389
Gross Unrealized Losses	13	35
Fair Value	3,269	3,214
Other corporate
Debt Securities, Available-for-sale [Line Items]
Fair Value	32,311	29,002
Other corporate | Yen-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	5,043	4,852
Gross Unrealized Gains	824	649
Gross Unrealized Losses	20	44
Fair Value	5,847	5,457
Other corporate | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	25,001	23,311
Gross Unrealized Gains	2,061	1,343
Gross Unrealized Losses	598	1,109
Fair Value	26,464	23,545
U.S. government and agencies | Dollar-denominated
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	190	137
Gross Unrealized Gains	11	9
Gross Unrealized Losses	1	1
Fair Value	$ 200	$ 145

INVESTMENTS - Held-to-Maturity

INVESTMENTS - Held-to-Maturity Debt Securities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	$ 30,163	$ 30,318
Gross Unrealized Gains	7,298	6,470
Gross Unrealized Losses	15	66
Fair Value	37,446	36,722
Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	30,163	30,318
Gross Unrealized Gains	7,298	6,470
Gross Unrealized Losses	15	66
Fair Value	37,446	36,722
Japan government and agencies | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	21,961	21,712
Gross Unrealized Gains	6,018	5,326
Gross Unrealized Losses	0	0
Fair Value	27,979	27,038
Municipalities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	814	359
Fair Value	1,061	469
Municipalities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	814	359
Gross Unrealized Gains	247	110
Gross Unrealized Losses	0	0
Fair Value	1,061	469
Mortgage- and asset-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	20	14
Fair Value	21	15
Mortgage- and asset-backed securities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	20	14
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	0
Fair Value	21	15
Public utilities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,728	2,727
Fair Value	3,068	2,973
Public utilities | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,728	2,727
Gross Unrealized Gains	340	254
Gross Unrealized Losses	0	8
Fair Value	3,068	2,973
Sovereign and supranational
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	1,154	1,551
Fair Value	1,332	1,840
Sovereign and supranational | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	1,154	1,551
Gross Unrealized Gains	178	289
Gross Unrealized Losses	0	0
Fair Value	1,332	1,840
Banks/financial institutions
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	949	1,445
Fair Value	1,039	1,583
Banks/financial institutions | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	949	1,445
Gross Unrealized Gains	100	158
Gross Unrealized Losses	10	20
Fair Value	1,039	1,583
Other corporate
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,537	2,510
Fair Value	2,946	2,804
Other corporate | Yen-denominated
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,537	2,510
Gross Unrealized Gains	414	332
Gross Unrealized Losses	5	38
Fair Value	$ 2,946	$ 2,804

INVESTMENTS - Equity Securities

INVESTMENTS - Equity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Equity Securities, FV-NI [Line Items]
Fair Value	$ 1,041	$ 987
Yen-denominated
Equity Securities, FV-NI [Line Items]
Fair Value	662	641
Dollar-denominated
Equity Securities, FV-NI [Line Items]
Fair Value	$ 379	$ 346

INVESTMENTS - Contractual and E

INVESTMENTS - Contractual and Economic Maturities of Investments in Fixed Maturities (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Available for sale:
Due in one year or less	$ 889
Due after one year through five years	8,483
Due after five years through 10 years	10,111
Due after 10 years	58,843
Mortgage- and asset-backed securities	380
Total fixed maturity securities, available for sale, amortized cost	78,706	$ 76,856
Held to maturity:
Due in one year or less	135
Due after one year through five years	1,112
Due after five years through 10 years	678
Due after 10 years	28,218
Mortgage- and asset-backed securities	20
Total fixed maturity securities, held to maturity, amortized cost	30,163	30,318
Available for sale:
Due in one year or less	950
Due after one year through five years	8,624
Due after five years through 10 years	11,034
Due after 10 years	66,902
Mortgage- and asset-backed securities	414
Total fixed maturity securities, available for sale, fair value	87,924	82,895
Held to maturity:
Due in one year or less	137
Due after one year through five years	1,187
Due after five years through 10 years	739
Due after 10 years	35,362
Mortgage- and asset-backed securities	21
Total fixed maturity securities, held to maturity, fair value	$ 37,446	$ 36,722

INVESTMENTS - Investment Exposu

INVESTMENTS - Investment Exposures Individually Exceeded 10% of Shareholders' Equity (Details) - Japan National Government - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Summary of Investment Holdings [Line Items]
Credit Rating	[1]	A+	A+
Amortized Cost	[1]	$ 51,775	$ 51,207
Fair Value	[1]	$ 62,275	$ 59,945
[1]	Japan Government Bonds (JGBs) or JGB-backed securities

INVESTMENTS - Information Regar

INVESTMENTS - Information Regarding Pretax Realized Gains and Losses From Investments (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Gain (Loss) on Securities [Line Items]
Other-than-temporary impairment losses realized	$ (2)	$ (7)
Loan loss reserves	(2)	(7)
Derivative gains (losses)	0	144
Foreign currency gains (losses)	(2)	(228)
Total realized investment gains (losses)	71	(134)
Loan receivables
Gain (Loss) on Securities [Line Items]
Total realized investment gains (losses)	(2)	(7)
Derivatives and other
Gain (Loss) on Securities [Line Items]
Total realized investment gains (losses)	(2)	(84)
Equity securities
Gain (Loss) on Securities [Line Items]
Total realized investment gains (losses)	58	(46)
Available-for-sale securities | Fixed maturities
Gain (Loss) on Securities [Line Items]
Gross gains from sales	12	10
Gross losses from sales	(8)	(2)
Foreign currency gains (losses) on sales and redemptions	13	(5)
Total realized investment gains (losses)	$ 17	$ 3

INVESTMENTS - Net Effect on Sha

INVESTMENTS - Net Effect on Shareholders' Equity of Unrealized Gains and Losses from Investment Securities (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Investments [Abstract]
Unrealized gains (losses) on securities available-for-sale	$ 9,218	$ 6,039
Deferred income taxes	(2,657)	(1,805)
Shareholders' equity, unrealized gains (losses) on fixed maturity securities	$ 6,561	$ 4,234

INVESTMENTS - Fair Value and Gr

INVESTMENTS - Fair Value and Gross Unrealized Losses for Securities That Have Been in Continuous Unrealized Loss Position (Detail) - Fixed maturity securities - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	$ 13,416	$ 24,484
Total Unrealized Losses	823	1,760
Less than 12 months Fair Value	6,745	16,389
Less than 12 months Unrealized Losses	417	985
12 months or longer Fair Value	6,671	8,095
12 months or longer Unrealized Losses	406	775
Dollar-denominated | U.S. government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	65	67
Total Unrealized Losses	1	1
Less than 12 months Fair Value	65	67
Less than 12 months Unrealized Losses	1	1
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Dollar-denominated | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		515
Total Unrealized Losses		8
Less than 12 months Fair Value		515
Less than 12 months Unrealized Losses		8
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Dollar-denominated | Mortgage- and asset-backed securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	53	74
Total Unrealized Losses	0	1
Less than 12 months Fair Value	53	74
Less than 12 months Unrealized Losses	0	1
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Dollar-denominated | Public utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	808	1,585
Total Unrealized Losses	32	105
Less than 12 months Fair Value	306	892
Less than 12 months Unrealized Losses	14	48
12 months or longer Fair Value	502	693
12 months or longer Unrealized Losses	18	57
Dollar-denominated | Banks/financial institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	345	625
Total Unrealized Losses	13	35
Less than 12 months Fair Value	209	340
Less than 12 months Unrealized Losses	10	19
12 months or longer Fair Value	136	285
12 months or longer Unrealized Losses	3	16
Dollar-denominated | Other corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	9,182	12,899
Total Unrealized Losses	598	1,109
Less than 12 months Fair Value	3,149	5,782
Less than 12 months Unrealized Losses	213	407
12 months or longer Fair Value	6,033	7,117
12 months or longer Unrealized Losses	385	702
Yen-denominated | Japan government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	139	3,604
Total Unrealized Losses	2	140
Less than 12 months Fair Value	139	3,604
Less than 12 months Unrealized Losses	2	140
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Yen-denominated | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	70	148
Total Unrealized Losses	3	9
Less than 12 months Fair Value	70	148
Less than 12 months Unrealized Losses	3	9
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Yen-denominated | Public utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		604
Total Unrealized Losses		12
Less than 12 months Fair Value		604
Less than 12 months Unrealized Losses		12
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Yen-denominated | Banks/financial institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	2,229	3,057
Total Unrealized Losses	149	258
Less than 12 months Fair Value	2,229	3,057
Less than 12 months Unrealized Losses	149	258
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	0	0
Yen-denominated | Other corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	525	1,306
Total Unrealized Losses	25	82
Less than 12 months Fair Value	525	1,306
Less than 12 months Unrealized Losses	25	82
12 months or longer Fair Value	0	0
12 months or longer Unrealized Losses	$ 0	$ 0

INVESTMENTS - Commercial Mortga

INVESTMENTS - Commercial Mortgage and Other Loans by Portfolio Segment (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Commercial Mortgage and Other Loans
Gross commercial mortgage and other loans	$ 7,209	$ 6,946
Valuation allowance	(29)	(27)
Commercial mortgage and other loans	7,180	6,919
Transitional real estate loans
Commercial Mortgage and Other Loans
Gross commercial mortgage and other loans	4,398	4,394
Valuation allowance	(18)	(17)
Commercial mortgage loans
Commercial Mortgage and Other Loans
Gross commercial mortgage and other loans	1,085	1,065
Valuation allowance	(1)	(1)
Middle market loans
Commercial Mortgage and Other Loans
Gross commercial mortgage and other loans	1,726	1,487
Valuation allowance	$ (10)	$ (9)

INVESTMENTS - Allowance for Loa

INVESTMENTS - Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Allowance for Loan Losses by Portfolio Segment [Roll Forward]
Balance, beginning of period	$ (27)
Addition to (release of) allowance for credit losses	(2)	$ (7)
Balance, end of period	(29)
Commercial mortgage loans
Allowance for Loan Losses by Portfolio Segment [Roll Forward]
Balance, beginning of period	(1)
Addition to (release of) allowance for credit losses	0
Balance, end of period	(1)
Transitional real estate loans
Allowance for Loan Losses by Portfolio Segment [Roll Forward]
Balance, beginning of period	(17)
Addition to (release of) allowance for credit losses	(1)
Balance, end of period	(18)
Middle market loans
Allowance for Loan Losses by Portfolio Segment [Roll Forward]
Balance, beginning of period	(9)
Addition to (release of) allowance for credit losses	(1)
Balance, end of period	$ (10)

INVESTMENTS - Other Investments

INVESTMENTS - Other Investments (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Other investments		$ 1,238	$ 787
Policy loans
Investment Holdings [Line Items]
Other investments		236	232
Short-term investments
Investment Holdings [Line Items]
Other investments	[1]	543	152
Limited partnerships
Investment Holdings [Line Items]
Other investments		434	377
Other
Investment Holdings [Line Items]
Other investments		$ 25	$ 26
[1]	Includes securities lending collateral

INVESTMENTS - Investments in Co

INVESTMENTS - Investments in Consolidated Variable Interest Entities (Detail) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Available for sale, fixed maturity securities, amortized cost		$ 78,706	$ 76,856
Available for sale, fixed maturity securities		87,924	82,895
Equity securities		1,041	987
Commercial mortgage and other loans		7,180	6,919
Commercial mortgage and other loans, fair value		7,185	6,893
Other investments		1,238	787
Asset derivatives		401	417
Assets, fair value		93,801	88,788
Liability derivatives		365	387
Liabilities		119,630	116,944
Liabilities, fair value		365	387
Variable Interest Entity, Consolidated
Variable Interest Entity [Line Items]
Available for sale, fixed maturity securities, amortized cost		3,756	3,849
Available for sale, fixed maturity securities		4,543	4,466
Equity securities, FV-NI, cost		180	160
Equity securities		180	160
Commercial mortgage and other loans		5,892	5,528
Commercial mortgage and other loans, fair value		5,894	5,506
Other investments	[1]	374	328
Other investments, fair value	[1]	374	328
Asset derivatives, amortized cost	[2]	178	182
Asset derivatives	[2]	178	182
Assets, amortized cost		10,380	10,047
Assets, fair value		11,169	10,642
Liability derivatives, amortized cost	[2]	108	102
Liability derivatives	[2]	108	102
Liabilities		108	102
Liabilities, fair value		$ 108	$ 102
[1]	Consists entirely of alternative investments in limited partnerships
[2]	Consists entirely of derivatives

INVESTMENTS - Investments in Va

INVESTMENTS - Investments in Variable Interest Entities Not Consolidated (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Available for sale, fixed maturity securities, amortized cost		$ 78,706	$ 76,856
Available for sale, fixed maturity securities		87,924	82,895
Securities held to maturity, fixed maturities, amortized cost		30,163	30,318
Held to maturity, fixed maturity securities, fair value		37,446	36,722
Other investments		1,238	787
Assets, fair value		93,801	88,788
Variable Interest Entity, Not Consolidated
Variable Interest Entity [Line Items]
Available for sale, fixed maturity securities, amortized cost		4,455	4,575
Available for sale, fixed maturity securities		5,025	4,982
Securities held to maturity, fixed maturities, amortized cost		2,006	2,007
Held to maturity, fixed maturity securities, fair value		2,331	2,254
Other investments	[1]	59	49
Other investments, fair value	[1]	59	49
Assets, amortized cost		6,520	6,631
Assets, fair value		$ 7,415	$ 7,285
[1]	Consists entirely of alternative investments in limited partnerships

INVESTMENTS - Securities Lendin

INVESTMENTS - Securities Lending Transactions Accounted for as Secured Borrowings (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		$ 3,870	$ 2,242
Gross amount of recognized liabilities for securities lending		1,969	1,052
Amounts related to agreements not included in offsetting disclosure in Note 4		1,901	1,190
Japan government and agencies
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		3,002	1,577
Municipalities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred			5
Public utilities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		15	27
Banks/financial institutions
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		74	74
Other corporate
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		764	549
Equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		15	10
Maturity Overnight and Continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]	868	665
Maturity Overnight and Continuous | Japan government and agencies
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]	0	0
Maturity Overnight and Continuous | Municipalities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]		5
Maturity Overnight and Continuous | Public utilities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]	15	27
Maturity Overnight and Continuous | Banks/financial institutions
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]	74	74
Maturity Overnight and Continuous | Other corporate
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]	764	549
Maturity Overnight and Continuous | Equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred	[1]	15	10
Maturity up to 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		1,101	387
Maturity up to 30 Days | Japan government and agencies
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		1,101	387
Maturity up to 30 Days | Municipalities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred			0
Maturity up to 30 Days | Public utilities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity up to 30 Days | Banks/financial institutions
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity up to 30 Days | Other corporate
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity up to 30 Days | Equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity Greater than 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		1,901	1,190
Maturity Greater than 90 Days | Japan government and agencies
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		1,901	1,190
Maturity Greater than 90 Days | Municipalities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred			0
Maturity Greater than 90 Days | Public utilities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity Greater than 90 Days | Banks/financial institutions
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity Greater than 90 Days | Other corporate
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		0	0
Maturity Greater than 90 Days | Equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred		$ 0	$ 0
[1]	The related loaned security, under the Company's U.S. securities lending program, can be returned to the Company at the transferee's discretion; therefore, they are classified as Overnight and Continuous

INVESTMENTS - Additional Inform

INVESTMENTS - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)investment	Mar. 31, 2018investment	Dec. 31, 2018USD ($)
Schedule of Investments [Line Items]
Held to maturity securities transferred to available for sale securities, number of investments | investment	0	0
Equity securities, FV-NI, unrealized gain (loss)	$ 47
Transitional real estate loans, average loan-to-value at origination, limit	70.00%
Transitional real estate loans, individual loan-to-value at origination, limit	80.00%
Transitional real estate loan commitments	$ 733
Commercial mortgage loans, average loan-to-value at origination, limit	65.00%
Commercial mortgage loans, individual loan-to-value at origination, limit	70.00%
Commercial mortgage loan commitments	$ 28
Middle market loan program unfunded amount	127		$ 56
Middle market loan commitments	677
Allowance for loan loss	29		$ 27
Limited partnerships investment commitments	$ 915
Percentage that the lending policy requires that the fair value of the securities received as collateral be of the fair value of the loaned securities	102.00%
Percentage that the lending policy requires that the fair value of the unrestricted cash received as collateral be of the fair value of the loaned securities	100.00%

DERIVATIVE INSTRUMENTS - Additi

DERIVATIVE INSTRUMENTS - Additional Information (Detail) $ in Millions	Mar. 31, 2019USD ($)yrcounterparties	Dec. 31, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Cash flow hedging activity, maximum time period | yr	8
Number of counterparties | counterparties	16
Number of counterparties that comprise majority of aggregate notional amount of swaps | counterparties	4
Percentage of notional amount of swaps from certain number of counterparties	65.00%
Derivative, net liability position, aggregate fair value	$ 133	$ 139
Additional collateral, aggregate fair value	23
4.00% senior notes due February 2022
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	350
3.625% senior notes due June 2023
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	700
3.625% senior notes due November 2024
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	750
3.25% senior notes due March 2025
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	$ 450

DERIVATIVE INSTRUMENTS - Summar

DERIVATIVE INSTRUMENTS - Summary of Balance Sheet Classification of Derivative Fair Value Amounts, as well as Gross Asset and Liability Fair Value Amounts (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	$ 39,051	$ 38,355
Derivative asset, fair value, gross asset including not subject to master netting arrangement	401	417
Derivative liability, fair value, gross liability including not subject to master netting arrangement	365	387
Asset derivatives fair value	223	234
Liability derivatives fair value	257	285
Cash flow hedges
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	75	75
Asset derivatives fair value	0	1
Liability derivatives fair value	6	4
Cash flow hedges | Foreign currency swaps | Variable Interest Entity
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	75	75
Asset derivatives fair value	0	1
Liability derivatives fair value	6	4
Fair value hedges
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	13,079	11,656
Asset derivatives fair value	0	3
Liability derivatives fair value	27	36
Fair value hedges | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	691	2,086
Asset derivatives fair value	0	0
Liability derivatives fair value	24	34
Fair value hedges | Foreign currency options
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	10,887	9,070
Asset derivatives fair value	0	3
Liability derivatives fair value	2	1
Fair value hedges | Interest rate swaptions
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	1,500	500
Asset derivatives fair value	0	0
Liability derivatives fair value	1	1
Non-qualifying strategies
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	25,897	26,624
Asset derivatives fair value	401	413
Liability derivatives fair value	332	347
Non-qualifying strategies | Foreign currency swaps | Variable Interest Entity
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	2,587	2,587
Asset derivatives fair value	178	181
Liability derivatives fair value	102	101
Non-qualifying strategies | Foreign currency swaps | Consolidated Entity Excluding Variable Interest Entities (VIE)
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	2,800	2,800
Asset derivatives fair value	96	103
Liability derivatives fair value	98	129
Non-qualifying strategies | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	15,208	16,057
Asset derivatives fair value	119	126
Liability derivatives fair value	132	117
Non-qualifying strategies | Foreign currency options
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	552	430
Asset derivatives fair value	0	0
Liability derivatives fair value	0	0
Non-qualifying strategies | Interest rate swaps
Derivatives, Fair Value [Line Items]
Net derivatives notional amount	4,750	4,750
Asset derivatives fair value	8	3
Liability derivatives fair value	$ 0	$ 0

DERIVATIVE INSTRUMENTS - Gains

DERIVATIVE INSTRUMENTS - Gains (Losses) Recognized on Fair Value Hedging Relationships (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives		$ 4	$ 413
Gains (losses) on derivatives excluded from effectiveness testing	[1]	(15)	(40)
Gains (losses) on derivatives included in effectiveness testing	[2]	19	453
Gains (losses) recognized for hedged items	[2]	(18)	(464)
Net realized gains (losses) recognized for fair value hedge		1	(11)
Fixed maturity securities | Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives		9	414
Gains (losses) on derivatives excluded from effectiveness testing	[1]	(10)	(39)
Gains (losses) on derivatives included in effectiveness testing	[2]	19	453
Gains (losses) recognized for hedged items	[2]	(18)	(464)
Net realized gains (losses) recognized for fair value hedge		1	(11)
Fixed maturity securities | Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives		(4)	(1)
Gains (losses) on derivatives excluded from effectiveness testing	[1]	(4)	(1)
Gains (losses) on derivatives included in effectiveness testing	[2]	0	0
Gains (losses) recognized for hedged items	[2]	0	0
Net realized gains (losses) recognized for fair value hedge		0	$ 0
Fixed maturity securities | Interest rate swaptions
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives		(1)
Gains (losses) on derivatives excluded from effectiveness testing	[1]	(1)
Gains (losses) on derivatives included in effectiveness testing	[2]	0
Gains (losses) recognized for hedged items	[2]	0
Net realized gains (losses) recognized for fair value hedge		$ 0
[1]	Gains (losses) excluded from effectiveness testing includes the forward point on foreign currency forwards and time value change on foreign currency options which are reported in the consolidated statement of earnings as realized investment gains (losses). It also includes the change in the fair value of the interest rate swaptions related to the time value of the swaptions which is recognized as a component of other comprehensive income (loss).
[2]	Gains and losses on foreign currency forwards and options and related hedged items are reported in the consolidated statement of earnings as realized investment gains (losses). For interest rate swaptions and related hedged items, gains and losses included in the hedge assessment are reported within net investment income. For the three -month period ended March 31, 2019

DERIVATIVE INSTRUMENTS - Schedu

DERIVATIVE INSTRUMENTS - Schedule of Interest Rate Fair Value Hedges Hedged Items (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount of Derivatives		$ 39,051	$ 38,355
Fair value hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount of Derivatives		13,079	11,656
Interest rate swaptions | Fair value hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount of Derivatives		1,500	500
Fixed maturity securities | Interest rate swaptions
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Assets/ (Liabilities)	[1]	5,285	6,593
Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of Hedged Assets/(Liabilities)		$ 276	$ 294
[1]	The balance includes hedging adjustment on discontinued hedging relationships of $276 in 2019 and $294

DERIVATIVE INSTRUMENTS - Deriva

DERIVATIVE INSTRUMENTS - Derivatives and Hedging Instruments Gain (Loss) Summary (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net	[1]	$ (1)	$ 0
Unrealized foreign currency translation gains (losses) during period		(1)	824
Derivative gains (losses)		0	144
Derivative and non-derivative hedging instruments gain (loss) recognized in other comprehensive income effective portion before tax	[2]	(3)	(86)
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net	[1]	(1)	0
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)	[3]	0	1
Gain (loss) recognized in other comprehensive income on derivative (effective portion)	[2]	(2)	6
Cash flow hedges | Foreign currency swaps | Variable Interest Entity
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net	[1]	(1)	0
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)		0	1
Gain (loss) recognized in other comprehensive income on derivative (effective portion)	[2]	(2)	6
Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net	[1]	0	0
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)		(13)	(51)
Gain (loss) recognized in other comprehensive income on derivative (effective portion)	[2]	(1)	0
Fair value hedges | Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)	[4]	(9)	(50)
Fair value hedges | Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)	[4]	(4)	(1)
Fair value hedges | Interest rate swaptions
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net	[1]	0	0
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)	[4]	0	0
Gain (loss) recognized in other comprehensive income on derivative (effective portion)	[2],[4]	(1)	0
Net investment hedge
Derivative Instruments, Gain (Loss) [Line Items]
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)		0	0
Unrealized foreign currency translation gains (losses) during period	[2]	0	(92)
Net investment hedge | Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)		0	0
Unrealized foreign currency translation gains (losses) during period	[2]	0	(8)
Net investment hedge | Non-derivative hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Net realized investment gains (losses) recognized in income on derivative (ineffective portion)		0	0
Unrealized foreign currency translation gains (losses) during period	[2]	0	(84)
Non-qualifying strategies
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net		13	194
Non-qualifying strategies | Foreign currency swaps | Variable Interest Entity
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net		(16)	124
Non-qualifying strategies | Foreign currency swaps | Consolidated Entity Excluding Variable Interest Entities (VIE)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net		44	(110)
Non-qualifying strategies | Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net		(21)	179
Non-qualifying strategies | Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net		0	1
Non-qualifying strategies | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net		$ 6	$ 0
[1]	Net investment income (loss) includes net interest on swaps.
[2]	Cash flow hedge items and the change in the fair value of interest rate swaptions related to the time value of the swaptions in fair value hedges are recorded as unrealized gains (losses) on derivatives and net investment hedge items are recorded in the unrealized foreign currency translation gains (losses) line in the consolidated statement of comprehensive income (loss).
[3]	Impact of cash flow hedges reported as realized investment gains (losses) includes an immaterial amount of gains or losses reclassified from accumulated other comprehensive income (loss) into earnings. It also includes an immaterial amount excluded from effectiveness testing during the three-month periods ended March 31, 2019 and 2018
[4]	Impact shown net of effect of hedged items (see Fair Value Hedges section of this Note 4 for further detail)

DERIVATIVE INSTRUMENTS - Offset

DERIVATIVE INSTRUMENTS - Offsetting of Financial Assets and Derivative Assets (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	$ 223	$ 234
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	223	234
Financial instruments, amount not offset	(118)	(152)
Derivative, collateral, obligation to return securities	(10)	(23)
Derivative, collateral, obligation to return cash	(81)	(58)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	14	1
Derivative asset, not subject to master netting arrangement	178	183
Derivative asset, fair value, amount offset against collateral, not subject to master netting agreement	178	183
Derivative asset, fair value, gross asset including not subject to master netting arrangement	401	417
Net amount of derivative assets presented in balance sheet	401	417
Derivative asset, fair value, amount offset against collateral	192	184
Gross amounts of recognized financial instruments	2,360	1,446
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	2,360	1,446
Carrying value of financial instruments not offset in balance sheet	(118)	(152)
Securities collateral, not offset in balance sheet	(10)	(23)
Cash collateral, not offset in balance sheet	(2,040)	(1,087)
Financial instruments, amount of assets offset against collateral	192	184
Over the Counter - Bilateral
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	215	231
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	215	231
Financial instruments, amount not offset	(118)	(152)
Derivative, collateral, obligation to return securities	(10)	(23)
Derivative, collateral, obligation to return cash	(80)	(55)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	7	1
Derivative asset, not subject to master netting arrangement	178	183
Derivative asset, fair value, amount offset against collateral, not subject to master netting agreement	178	183
Other the Counter - Cleared
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	8	3
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in balance sheet	8	3
Financial instruments, amount not offset	0	0
Derivative, collateral, obligation to return securities	0	0
Derivative, collateral, obligation to return cash	(1)	(3)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	7	0
Securities Lending and Similar Arrangements
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	1,959	1,029
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	1,959	1,029
Carrying value of financial instruments not offset in balance sheet	0	0
Securities collateral, not offset in balance sheet	0	0
Cash collateral, not offset in balance sheet	(1,959)	(1,029)
Financial instruments, amount of assets offset against collateral	$ 0	$ 0

DERIVATIVE INSTRUMENTS - Offs_2

DERIVATIVE INSTRUMENTS - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	$ 257	$ 285
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	257	285
Financial instruments, amount not offset	(118)	(152)
Derivative, collateral, right to reclaim securities	(65)	(37)
Derivative, collateral, right to reclaim cash	(45)	(68)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	29	28
Derivative liability, not subject to master netting arrangement	108	102
Derivative liability, fair value, amount offset against collateral, not subject to master netting agreement	108	102
Derivative liability, fair value, gross liability including not subject to master netting arrangement	365	387
Net amount of derivative liabilities presented in balance sheet	365	387
Derivative liability, fair value, amount offset against collateral	137	130
Gross Amounts of Recognized Financial Instruments, Offsetting Liabilities	2,334	1,439
Gross Amounts Offset in Statement of Financial Position, Offsetting Liabilities	0	0
Net Amounts of Financial Instruments Presented in Balance Sheet, Offsetting Liabilities	2,334	1,439
Carrying value of financial instruments, liabilities not offset in balance sheet	(2,077)	(1,181)
Securities Collateral, Liabilities Not Offset in Balance Sheet	(65)	(37)
Cash Collateral, Liabilities Not Offset in Balance Sheet	(45)	(68)
Financial instruments, amount of liabilities offset against collateral	147	153
Over the Counter - Bilateral
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	257	285
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	257	285
Financial instruments, amount not offset	(118)	(152)
Derivative, collateral, right to reclaim securities	(65)	(37)
Derivative, collateral, right to reclaim cash	(45)	(68)
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	29	28
Derivative liability, not subject to master netting arrangement	108	102
Derivative liability, fair value, amount offset against collateral, not subject to master netting agreement	108	102
Securities Lending and Similar Arrangements
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Financial Instruments, Offsetting Liabilities	1,969	1,052
Gross Amounts Offset in Statement of Financial Position, Offsetting Liabilities	0	0
Net Amounts of Financial Instruments Presented in Balance Sheet, Offsetting Liabilities	1,969	1,052
Carrying value of financial instruments, liabilities not offset in balance sheet	(1,959)	(1,029)
Securities Collateral, Liabilities Not Offset in Balance Sheet	0	0
Cash Collateral, Liabilities Not Offset in Balance Sheet	0	0
Financial instruments, amount of liabilities offset against collateral	$ 10	$ 23

FAIR VALUE MEASUREMENTS - Fair

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets:
Available for sale, fixed maturity securities	$ 87,924	$ 82,895
Equity securities	1,041	987
Other investments	543	152
Cash and cash equivalents	3,892	4,337
Asset derivatives	401	417
Total assets	93,801	88,788
Liabilities:
Liability derivatives	365	387
Total liabilities	365	387
Foreign currency swaps
Assets:
Asset derivatives	274	285
Liabilities:
Liability derivatives	206	234
Foreign currency forwards
Assets:
Asset derivatives	119	126
Liabilities:
Liability derivatives	156	151
Foreign currency options
Assets:
Asset derivatives		3
Liabilities:
Liability derivatives	2	1
Interest rate swaps
Assets:
Asset derivatives	8	3
Interest rate swaptions
Liabilities:
Liability derivatives	1	1
Government and agencies
Assets:
Available for sale, fixed maturity securities	36,249	34,342
Municipalities
Assets:
Available for sale, fixed maturity securities	1,908	1,863
Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	414	339
Public utilities
Assets:
Available for sale, fixed maturity securities	6,497	7,171
Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	1,154	1,260
Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	9,391	8,918
Other corporate
Assets:
Available for sale, fixed maturity securities	32,311	29,002
Level 1
Assets:
Available for sale, fixed maturity securities	34,727	32,993
Equity securities	925	874
Other investments	543	152
Cash and cash equivalents	3,892	4,337
Asset derivatives	0	0
Total assets	40,087	38,356
Liabilities:
Total liabilities	0	0
Level 1 | Foreign currency swaps
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 1 | Foreign currency options
Assets:
Asset derivatives		0
Liabilities:
Liability derivatives	0	0
Level 1 | Interest rate swaps
Assets:
Asset derivatives	0	0
Level 1 | Interest rate swaptions
Liabilities:
Liability derivatives	0	0
Level 1 | Government and agencies
Assets:
Available for sale, fixed maturity securities	34,727	32,993
Level 1 | Municipalities
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 | Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 | Public utilities
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 | Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 | Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	0	0
Level 1 | Other corporate
Assets:
Available for sale, fixed maturity securities	0	0
Level 2
Assets:
Available for sale, fixed maturity securities	52,627	49,380
Equity securities	70	67
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	223	235
Total assets	52,920	49,682
Liabilities:
Total liabilities	257	285
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	96	103
Liabilities:
Liability derivatives	98	132
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	119	126
Liabilities:
Liability derivatives	156	151
Level 2 | Foreign currency options
Assets:
Asset derivatives		3
Liabilities:
Liability derivatives	2	1
Level 2 | Interest rate swaps
Assets:
Asset derivatives	8	3
Level 2 | Interest rate swaptions
Liabilities:
Liability derivatives	1	1
Level 2 | Government and agencies
Assets:
Available for sale, fixed maturity securities	1,522	1,349
Level 2 | Municipalities
Assets:
Available for sale, fixed maturity securities	1,908	1,863
Level 2 | Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	236	162
Level 2 | Public utilities
Assets:
Available for sale, fixed maturity securities	6,412	7,062
Level 2 | Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	1,154	1,260
Level 2 | Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	9,368	8,895
Level 2 | Other corporate
Assets:
Available for sale, fixed maturity securities	32,027	28,789
Level 3
Assets:
Available for sale, fixed maturity securities	570	522
Equity securities	46	46
Other investments	0	0
Cash and cash equivalents	0	0
Asset derivatives	178	182
Total assets	794	750
Liabilities:
Total liabilities	108	102
Level 3 | Foreign currency swaps
Assets:
Asset derivatives	178	182
Liabilities:
Liability derivatives	108	102
Level 3 | Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 | Foreign currency options
Assets:
Asset derivatives		0
Liabilities:
Liability derivatives	0	0
Level 3 | Interest rate swaps
Assets:
Asset derivatives	0	0
Level 3 | Interest rate swaptions
Liabilities:
Liability derivatives	0	0
Level 3 | Government and agencies
Assets:
Available for sale, fixed maturity securities	0	0
Level 3 | Municipalities
Assets:
Available for sale, fixed maturity securities	0	0
Level 3 | Mortgage- and asset-backed securities
Assets:
Available for sale, fixed maturity securities	178	177
Level 3 | Public utilities
Assets:
Available for sale, fixed maturity securities	85	109
Level 3 | Sovereign and supranational
Assets:
Available for sale, fixed maturity securities	0	0
Level 3 | Banks/financial institutions
Assets:
Available for sale, fixed maturity securities	23	23
Level 3 | Other corporate
Assets:
Available for sale, fixed maturity securities	$ 284	$ 213

FAIR VALUE MEASUREMENTS - Fai_2

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Carried at Cost or Amortized Cost (Details) - USD ($) $ in Millions	Mar. 31, 2019		Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 1,238		$ 787
Assets:
Securities held to maturity, fixed maturities, amortized cost	30,163		30,318
Held to maturity, fixed maturity securities, fair value	37,446		36,722
Commercial mortgage and other loans	7,180		6,919
Commercial mortgage and other loans, fair value	7,185		6,893
Other investments carried at amortized cost	25	[1]	26	[2]
Other investments carried at amortized cost, fair value	25	[1]	26	[2]
Total financial instruments assets not carried at fair value	37,368		37,263
Assets fair value disclosure financial instruments carried at cost	44,656		43,641
Liabilities:
Other policyholders’ funds	7,185		7,146
Other policyholders' funds fair value disclosure	7,110		7,067
Notes payable	5,766		5,765
Notes payable, fair value disclosure	6,079		5,876
Total financial instrument liabilities not carried at fair value	12,951		12,911
Liabilities fair value disclosure financial instruments carried at cost	13,189		12,943
Government and agencies
Assets:
Securities held to maturity, fixed maturities, amortized cost	21,961		21,712
Held to maturity, fixed maturity securities, fair value	27,979		27,038
Municipalities
Assets:
Securities held to maturity, fixed maturities, amortized cost	814		359
Held to maturity, fixed maturity securities, fair value	1,061		469
Mortgage- and asset-backed securities
Assets:
Securities held to maturity, fixed maturities, amortized cost	20		14
Held to maturity, fixed maturity securities, fair value	21		15
Public utilities
Assets:
Securities held to maturity, fixed maturities, amortized cost	2,728		2,727
Held to maturity, fixed maturity securities, fair value	3,068		2,973
Sovereign and supranational
Assets:
Securities held to maturity, fixed maturities, amortized cost	1,154		1,551
Held to maturity, fixed maturity securities, fair value	1,332		1,840
Banks/financial institutions
Assets:
Securities held to maturity, fixed maturities, amortized cost	949		1,445
Held to maturity, fixed maturity securities, fair value	1,039		1,583
Other corporate
Assets:
Securities held to maturity, fixed maturities, amortized cost	2,537		2,510
Held to maturity, fixed maturity securities, fair value	2,946		2,804
Policy loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	236		232
Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	434		377
Level 1
Assets:
Held to maturity, fixed maturity securities, fair value	27,629		27,030
Commercial mortgage and other loans, fair value	0		0
Other investments carried at amortized cost, fair value	0	[1]	0	[2]
Assets fair value disclosure financial instruments carried at cost	27,629		27,030
Liabilities:
Other policyholders' funds fair value disclosure	0		0
Notes payable, fair value disclosure	0		0
Liabilities fair value disclosure financial instruments carried at cost	0		0
Level 1 | Government and agencies
Assets:
Held to maturity, fixed maturity securities, fair value	27,629		27,030
Level 1 | Municipalities
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 1 | Mortgage- and asset-backed securities
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 1 | Public utilities
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 1 | Sovereign and supranational
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 1 | Banks/financial institutions
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 1 | Other corporate
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 2
Assets:
Held to maturity, fixed maturity securities, fair value	9,804		9,677
Commercial mortgage and other loans, fair value	0		0
Other investments carried at amortized cost, fair value	25	[1]	26	[2]
Assets fair value disclosure financial instruments carried at cost	9,829		9,703
Liabilities:
Other policyholders' funds fair value disclosure	0		0
Notes payable, fair value disclosure	5,809		5,606
Liabilities fair value disclosure financial instruments carried at cost	5,809		5,606
Level 2 | Government and agencies
Assets:
Held to maturity, fixed maturity securities, fair value	350		8
Level 2 | Municipalities
Assets:
Held to maturity, fixed maturity securities, fair value	1,061		469
Level 2 | Mortgage- and asset-backed securities
Assets:
Held to maturity, fixed maturity securities, fair value	8		0
Level 2 | Public utilities
Assets:
Held to maturity, fixed maturity securities, fair value	3,068		2,973
Level 2 | Sovereign and supranational
Assets:
Held to maturity, fixed maturity securities, fair value	1,332		1,840
Level 2 | Banks/financial institutions
Assets:
Held to maturity, fixed maturity securities, fair value	1,039		1,583
Level 2 | Other corporate
Assets:
Held to maturity, fixed maturity securities, fair value	2,946		2,804
Level 3
Assets:
Held to maturity, fixed maturity securities, fair value	13		15
Commercial mortgage and other loans, fair value	7,185		6,893
Other investments carried at amortized cost, fair value	0	[1]	0	[2]
Assets fair value disclosure financial instruments carried at cost	7,198		6,908
Liabilities:
Other policyholders' funds fair value disclosure	7,110		7,067
Notes payable, fair value disclosure	270		270
Liabilities fair value disclosure financial instruments carried at cost	7,380		7,337
Level 3 | Government and agencies
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 3 | Municipalities
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 3 | Mortgage- and asset-backed securities
Assets:
Held to maturity, fixed maturity securities, fair value	13		15
Level 3 | Public utilities
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 3 | Sovereign and supranational
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 3 | Banks/financial institutions
Assets:
Held to maturity, fixed maturity securities, fair value	0		0
Level 3 | Other corporate
Assets:
Held to maturity, fixed maturity securities, fair value	$ 0		$ 0
[1]	Excludes policy loans of $236 and equity method investments of $434
[2]	Excludes policy loans of $232 and equity method investments of $377

FAIR VALUE MEASUREMENTS - Fai_3

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets by Pricing Source, Securities Carried at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	$ 87,924	$ 82,895
Equity securities	1,041	987
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	34,727	32,993
Equity securities	925	874
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	52,627	49,380
Equity securities	70	67
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	570	522
Equity securities	46	46
Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	995	941
Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	925	874
Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	70	67
Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Net asset value valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	46	46
Net asset value valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Net asset value valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Net asset value valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	46	46
Government and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	36,249	34,342
Government and agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	34,727	32,993
Government and agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,522	1,349
Government and agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Government and agencies | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	36,249	34,342
Government and agencies | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	34,727	32,993
Government and agencies | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,522	1,349
Government and agencies | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,908	1,863
Municipalities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,908	1,863
Municipalities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,908	1,863
Municipalities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,908	1,863
Municipalities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	414	339
Mortgage- and asset-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	236	162
Mortgage- and asset-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	178	177
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	236	162
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	236	162
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	178	177
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	178	177
Public utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	6,497	7,171
Public utilities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	6,412	7,062
Public utilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	85	109
Public utilities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	6,412	7,062
Public utilities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	6,412	7,062
Public utilities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Discounted cash flow technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	85	109
Public utilities | Discounted cash flow technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Discounted cash flow technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Discounted cash flow technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	85	109
Sovereign and supranational
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,154	1,260
Sovereign and supranational | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Sovereign and supranational | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,154	1,260
Sovereign and supranational | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Sovereign and supranational | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,154	1,260
Sovereign and supranational | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Sovereign and supranational | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	1,154	1,260
Sovereign and supranational | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	9,391	8,918
Banks/financial institutions | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	9,368	8,895
Banks/financial institutions | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	23	23
Banks/financial institutions | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	9,323	8,895
Banks/financial institutions | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	9,323	8,895
Banks/financial institutions | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	68	23
Banks/financial institutions | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	45	0
Banks/financial institutions | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	23	23
Other corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	32,311	29,002
Other corporate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	32,027	28,789
Other corporate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	284	213
Other corporate | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	31,964	28,789
Other corporate | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	31,964	28,789
Other corporate | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Discounted cash flow technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	347	213
Other corporate | Discounted cash flow technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Discounted cash flow technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	63	0
Other corporate | Discounted cash flow technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, fixed maturity securities	$ 284	$ 213

FAIR VALUE MEASUREMENTS - Fai_4

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets by Pricing Source, Securities Carried at Amortized Cost (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	$ 37,446	$ 36,722
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	27,629	27,030
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	9,804	9,677
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	13	15
Government and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	27,979	27,038
Government and agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	27,629	27,030
Government and agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	350	8
Government and agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Government and agencies | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	27,979	27,038
Government and agencies | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	27,629	27,030
Government and agencies | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	350	8
Government and agencies | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Municipalities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,061	469
Municipalities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Municipalities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,061	469
Municipalities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Municipalities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,061	469
Municipalities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Municipalities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,061	469
Municipalities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Mortgage- and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	21	15
Mortgage- and asset-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Mortgage- and asset-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	8	0
Mortgage- and asset-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	13	15
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	8
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	8
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	13	15
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	13	15
Public utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	3,068	2,973
Public utilities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Public utilities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	3,068	2,973
Public utilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Public utilities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	3,068	2,973
Public utilities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Public utilities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	3,068	2,973
Public utilities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Sovereign and supranational
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,332	1,840
Sovereign and supranational | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Sovereign and supranational | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,332	1,840
Sovereign and supranational | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Sovereign and supranational | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,332	1,840
Sovereign and supranational | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Sovereign and supranational | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,332	1,840
Sovereign and supranational | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Banks/financial institutions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,039	1,583
Banks/financial institutions | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Banks/financial institutions | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,039	1,583
Banks/financial institutions | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Banks/financial institutions | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,039	1,583
Banks/financial institutions | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Banks/financial institutions | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	1,039	1,583
Banks/financial institutions | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Other corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	2,946	2,804
Other corporate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Other corporate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	2,946	2,804
Other corporate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Other corporate | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	2,946	2,804
Other corporate | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	0	0
Other corporate | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	2,946	2,804
Other corporate | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held to maturity, fixed maturity securities, fair value	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Chang

FAIR VALUE MEASUREMENTS - Changes in Investments and Derivatives Carried at Fair Value Classified as Level 3 (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		$ 648		$ 453
Realized investment gains (losses) included in earnings		(8)		126
Unrealized gains (losses) included in other comprehensive income (loss)		1		13
Purchases		63		16
Issuances		0		0
Sales		(2)		0
Settlements		0		(1)
Transfers into Level 3		25		0
Transfers out of Level 3		(41)		0
Balance, end of period		686		607
Change in unrealized gains (losses) still held		(8)		126
Foreign currency swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	[1]	80		22
Realized gains or losses included in earnings	[1]	(8)		126
Unrealized gains or losses included in other comprehensive income (loss)	[1]	(2)		6
Purchases	[1]	0		0
Issuances	[1]	0		0
Sales	[1]	0		0
Settlements	[1]	0		0
Transfers into Level 3	[1]	0		0
Transfers out of Level 3	[1]	0		0
Balance, end of period	[1]	70		154
Changes in unrealized gain (losses) still held	[1]	(8)		126
Credit default swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	[1]	0		1
Realized gains or losses included in earnings	[1]	0		0
Unrealized gains or losses included in other comprehensive income (loss)	[1]	0		0
Purchases	[1]	0		0
Issuances	[1]	0		0
Sales	[1]	0		0
Settlements	[1]	0		0
Transfers into Level 3	[1]	0		0
Transfers out of Level 3	[1]	0		0
Balance, end of period	[1]	0		1
Changes in unrealized gain (losses) still held	[1]	0		0
Fixed maturity securities | Mortgage- and asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		177		175
Realized investment gains (losses) included in earnings		0		0
Unrealized gains (losses) included in other comprehensive income (loss)		1		11
Purchases		0		0
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Balance, end of period		178		186
Change in unrealized gains (losses) still held		0		0
Fixed maturity securities | Public utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		109		68
Realized investment gains (losses) included in earnings		0		0
Unrealized gains (losses) included in other comprehensive income (loss)		1		(1)
Purchases		0		16
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		(25)	[2]	0
Balance, end of period		85		83
Change in unrealized gains (losses) still held		0		0
Fixed maturity securities | Banks/financial institutions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		23		25
Realized investment gains (losses) included in earnings		0		0
Unrealized gains (losses) included in other comprehensive income (loss)		0		(1)
Purchases		0		0
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Balance, end of period		23		24
Change in unrealized gains (losses) still held		0		0
Fixed maturity securities | Other corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		213		146
Realized investment gains (losses) included in earnings		0		0
Unrealized gains (losses) included in other comprehensive income (loss)		1		(2)
Purchases		63		0
Issuances		0		0
Sales		(2)		0
Settlements		0		(1)
Transfers into Level 3		25	[2]	0
Transfers out of Level 3		(16)	[3]	0
Balance, end of period		284		143
Change in unrealized gains (losses) still held		0		0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		46		16
Realized investment gains (losses) included in earnings		0		0
Unrealized gains (losses) included in other comprehensive income (loss)		0		0
Purchases		0		0
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Balance, end of period		46		16
Change in unrealized gains (losses) still held		$ 0		$ 0
[1]	Derivative assets and liabilities are presented net
[2]	Transfer due to sector classification change
[3]	Transfer due to availability of observable market inputs

FAIR VALUE MEASUREMENTS - Fai_5

FAIR VALUE MEASUREMENTS - Fair Value Measurement Inputs and Valuation Techniques (Details) $ in Millions		Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		$ 87,924	$ 82,895
Equity securities		1,041	987
Asset derivatives		401	417
Liability derivatives		365	387
Assets, fair value		93,801	88,788
Liabilities, fair value		365	387
Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		570	522
Equity securities		46	46
Asset derivatives		178	182
Assets, fair value		794	750
Liabilities, fair value		108	102
Net asset value valuation technique
Fair Value Measurement Inputs and Valuation Techniques
Equity securities		46	46
Net asset value valuation technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Equity securities		46	46
Foreign currency swaps
Fair Value Measurement Inputs and Valuation Techniques
Asset derivatives		274	285
Liability derivatives		206	234
Foreign currency swaps | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Asset derivatives		178	182
Liability derivatives		108	102
Foreign currency swaps | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Discounted cash flow technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Asset derivatives		117	125
Liability derivatives		102	98
Foreign currency swaps | Fair Value, Unobservable Input, Interest Rates (USD) and Interest Rates (JPY) | Discounted cash flow technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Asset derivatives		61	57
Liability derivatives		$ 6	$ 4
Foreign currency swaps | Credit Spread | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input		0.0013	0.0019
Derivative liability, measurement input		0.0030	0.0028
Foreign currency swaps | Credit Spread | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input		0.0109	0.0120
Derivative liability, measurement input		0.0187	0.0211
Dollar-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		$ 36,076	$ 33,995
Equity securities		$ 379	$ 346
Dollar-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[1]	0.0248	0.0275
Derivative liability, measurement input	[1]	0.0248	0.0275
Dollar-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[1]	0.0266	0.0284
Derivative liability, measurement input	[1]	0.0266	0.0284
Dollar-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD) and Interest Rates (JPY) | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[1]	0.0248	0.0275
Derivative liability, measurement input	[1]	0.0248	0.0275
Dollar-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD) and Interest Rates (JPY) | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[1]	0.0266	0.0284
Derivative liability, measurement input	[1]	0.0266	0.0284
Yen-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		$ 51,848	$ 48,900
Equity securities		$ 662	$ 641
Yen-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[2]	0.0013	0.0018
Derivative liability, measurement input	[2]	0.0013	0.0018
Yen-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY) and CDS Spreads | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[2]	0.0057	0.0071
Derivative liability, measurement input	[2]	0.0057	0.0071
Yen-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD) and Interest Rates (JPY) | Lower Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[2]	0.0013	0.0018
Derivative liability, measurement input	[2]	0.0013	0.0018
Yen-denominated | Foreign currency swaps | Discount Rate | Fair Value, Unobservable Input, Interest Rates (USD) and Interest Rates (JPY) | Upper Limit | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Derivative asset, measurement input	[2]	0.0057	0.0071
Derivative liability, measurement input	[2]	0.0057	0.0071
Mortgage- and asset-backed securities
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		$ 414	$ 339
Mortgage- and asset-backed securities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		178	177
Mortgage- and asset-backed securities | Consensus pricing valuation technique
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		178	177
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		178	177
Mortgage- and asset-backed securities | Dollar-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		154	162
Mortgage- and asset-backed securities | Yen-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		260	177
Banks/financial institutions
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		9,391	8,918
Banks/financial institutions | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		23	23
Banks/financial institutions | Consensus pricing valuation technique
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		68	23
Banks/financial institutions | Consensus pricing valuation technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		23	23
Banks/financial institutions | Dollar-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		3,269	3,214
Banks/financial institutions | Yen-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		6,122	5,704
Public utilities
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		6,497	7,171
Public utilities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		85	109
Public utilities | Discounted cash flow technique
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		85	109
Public utilities | Discounted cash flow technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		85	109
Public utilities | Dollar-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		4,331	5,163
Public utilities | Yen-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		2,166	2,008
Other corporate
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		32,311	29,002
Other corporate | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		284	213
Other corporate | Discounted cash flow technique
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		347	213
Other corporate | Discounted cash flow technique | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		284	213
Other corporate | Dollar-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		26,464	23,545
Other corporate | Yen-denominated
Fair Value Measurement Inputs and Valuation Techniques
Available for sale, fixed maturity securities		$ 5,847	$ 5,457
[1]	Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps
[2]	Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps

FAIR VALUE MEASUREMENTS - Addit

FAIR VALUE MEASUREMENTS - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$ 0	$ 0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	$ 0	$ 0

POLICY LIABILITIES - Changes in

POLICY LIABILITIES - Changes in Liability for Unpaid Policy Claims (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Liability for Unpaid Claims and Claims Expenses
Net balance, beginning of period	$ 4,584
Less claims paid during the period on claims incurred during:
Net balance, end of period	4,625
Total liability for unpaid policy claims	4,625	$ 4,630
Health insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of period	3,952	3,884
Less reinsurance recoverables	29	30
Net balance, beginning of period	3,923	3,854
Add claims incurred during the period related to:
Current year	1,825	1,842
Prior years	(167)	(192)
Total incurred	1,658	1,650
Less claims paid during the period on claims incurred during:
Current year	506	518
Prior years	1,137	1,116
Total paid	1,643	1,634
Effect of foreign exchange rate changes on unpaid claims	0	142
Net balance, end of period	3,938	4,012
Add reinsurance recoverables	29	31
Total liability for unpaid policy claims	3,967	4,043
Life insurance
Less claims paid during the period on claims incurred during:
Total liability for unpaid policy claims	$ 658	$ 587

POLICY LIABILITIES - Additional

POLICY LIABILITIES - Additional Information (Details) - Health insurance - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense	$ (167)	$ (192)
Aflac Japan
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense	$ (91)
Percentage of total prior year claims and claims adjustment expense	54.00%

REINSURANCE - Additional Infor

REINSURANCE - Additional Information (Details) $ in Millions, ¥ in Billions	3 Months Ended
	Mar. 31, 2019JPY (¥)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Effects of Reinsurance [Line Items]
Percent change in ceded reserves		0.30%
Aflac Japan
Effects of Reinsurance [Line Items]
Committed reinsurance facility | ¥	¥ 110
Aflac Japan | Closed Block
Effects of Reinsurance [Line Items]
Reinsurance deferred profit liability		$ 1,000
Reinsurance recoverable		$ 944	$ 941

REINSURANCE - Effect of Reinsu

REINSURANCE - Effect of Reinsurance on Premiums and Benefits and Claims (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Effects of Reinsurance [Line Items]
Direct premium income	$ 4,776	$ 4,833
Net premium income	4,691	4,745
Direct benefits and claims	3,041	3,119
Benefits and claims, net	2,967	3,042
All other
Effects of Reinsurance [Line Items]
Ceded premiums	(15)	(15)
Assumed premiums earned	1	2
Ceded benefits and claims	(11)	(12)
Aflac Japan
Effects of Reinsurance [Line Items]
Net premium income	3,180	3,263
Aflac Japan | Closed Block
Effects of Reinsurance [Line Items]
Ceded premiums	(121)	(129)
Assumed premiums earned	50	54
Ceded benefits and claims	(111)	(117)
Assumed benefits and claims from other companies	48	52
Intercompany eliminations
Effects of Reinsurance [Line Items]
Ceded benefits and claims	10	12
Assumed benefits and claims from other companies	$ (10)	$ (12)

NOTES PAYABLE AND LEASE OBLIG_3

NOTES PAYABLE AND LEASE OBLIGATIONS - Additional Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Debt Instrument [Line Items]
Operating lease, cost	$ 14
Operating lease, payments	14
Lines of credit
Debt Instrument [Line Items]
Debt instrument, debt default, amount	0
Notes Payable
Debt Instrument [Line Items]
Debt instrument, debt default, amount	$ 0

NOTES PAYABLE AND LEASE OBLIG_4

NOTES PAYABLE AND LEASE OBLIGATIONS - Summary of Notes Payable (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Notes payable and lease obligations	[1]	$ 5,900	$ 5,778
Finance lease obligations		12	13
Operating lease obligations	[1]	122	0
4.00% senior notes due February 2022
Debt Instrument [Line Items]
Notes payable and lease obligations		348	348
3.625% senior notes due June 2023
Debt Instrument [Line Items]
Notes payable and lease obligations		698	698
3.625% senior notes due November 2024
Debt Instrument [Line Items]
Notes payable and lease obligations		746	746
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Notes payable and lease obligations		448	447
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Notes payable and lease obligations		297	297
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Notes payable and lease obligations		220	220
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Notes payable and lease obligations		254	254
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Notes payable and lease obligations		394	394
4.750% senior notes due January 2049
Debt Instrument [Line Items]
Notes payable and lease obligations		540	540
.932% senior notes due January 2027
Debt Instrument [Line Items]
Notes payable and lease obligations		538	538
1.159% senior notes due October 2030
Debt Instrument [Line Items]
Notes payable and lease obligations		262	262
1.488% senior notes due October 2033
Debt Instrument [Line Items]
Notes payable and lease obligations		136	136
1.750% senior notes due October 2038
Debt Instrument [Line Items]
Notes payable and lease obligations		79	79
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Notes payable and lease obligations		536	536
Yen-denominated loan variable interest rate due September 2021
Debt Instrument [Line Items]
Notes payable and lease obligations		45	45
Yen-denominated loan variable interest rate due September 2023
Debt Instrument [Line Items]
Notes payable and lease obligations		$ 225	$ 225
[1]	See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2019 related to leases.

NOTES PAYABLE AND LEASE OBLIG_5

NOTES PAYABLE AND LEASE OBLIGATIONS - Summary of Notes Payable (Parenthetical) (Details) $ in Millions, ¥ in Billions	Mar. 31, 2019USD ($)	Mar. 31, 2019JPY (¥)	Dec. 31, 2018JPY (¥)
4.00% senior notes due February 2022
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%	4.00%	4.00%
Debt instrument, principal amount | $	$ 350
3.625% senior notes due June 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	3.625%	3.625%	3.625%
Debt instrument, principal amount | $	$ 700
3.625% senior notes due November 2024
Debt Instrument [Line Items]
Debt instrument, interest rate	3.625%	3.625%	3.625%
Debt instrument, principal amount | $	$ 750
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Debt instrument, interest rate	3.25%	3.25%	3.25%
Debt instrument, principal amount | $	$ 450
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Debt instrument, interest rate	2.875%	2.875%	2.875%
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Debt instrument, interest rate	6.90%	6.90%	6.90%
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Debt instrument, interest rate	6.45%	6.45%	6.45%
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%	4.00%	4.00%
4.750% senior notes due January 2049
Debt Instrument [Line Items]
Debt instrument, interest rate	4.75%	4.75%	4.75%
.932% senior notes due January 2027
Debt Instrument [Line Items]
Debt instrument, interest rate	0.932%	0.932%	0.932%
Debt instrument, principal amount		¥ 60	¥ 60
1.159% senior notes due October 2030
Debt Instrument [Line Items]
Debt instrument, interest rate	1.159%	1.159%	1.159%
Debt instrument, principal amount		¥ 29.3	¥ 29.3
1.488% senior notes due October 2033
Debt Instrument [Line Items]
Debt instrument, interest rate	1.488%	1.488%	1.488%
Debt instrument, principal amount		¥ 15.2	¥ 15.2
1.750% senior notes due October 2038
Debt Instrument [Line Items]
Debt instrument, interest rate	1.75%	1.75%	1.75%
Debt instrument, principal amount		¥ 8.9	¥ 8.9
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Debt instrument, interest rate	2.108%	2.108%	2.108%
Debt instrument, principal amount		¥ 60	¥ 60
Yen-denominated loan variable interest rate due September 2021
Debt Instrument [Line Items]
Debt instrument, interest rate	0.32%	0.32%	0.32%
Debt instrument, principal amount		¥ 5	¥ 5
Yen-denominated loan variable interest rate due September 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	0.47%	0.47%	0.47%
Debt instrument, principal amount		¥ 25	¥ 25

NOTES PAYABLE AND LEASE OBLIG_6

NOTES PAYABLE AND LEASE OBLIGATIONS - Contractual Maturities of Leases (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019		$ 33
2020		30
2021		20
2022		17
2023		9
After 2023		24
Total lease payments		133
Less: Interest		11
Present value of lease liabilities	[1]	122	$ 0
Finance Leases
2019		3
2020		3
2021		2
2022		2
2023		1
After 2023		1
Total lease payments		12
Less: Interest		0
Present value of lease liabilities		12	$ 13
Total
2019		36
2020		33
2021		22
2022		19
2023		10
After 2023		25
Total lease payments		145
Less: Interest		11
Present value of lease liabilities		$ 134
[1]	See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2019 related to leases.

NOTES PAYABLE AND LEASE OBLIG_7

NOTES PAYABLE AND LEASE OBLIGATIONS - Weighted Average Lease Term and Discount Rate (Details)	Mar. 31, 2019
Debt Disclosure [Abstract]
Operating lease, weighted average remaining lease term	4 years 4 months 24 days
Finance lease, weighted average remaining lease term	3 years 9 months 18 days
Operating lease, weighted average discount rate, percent	2.55%
Finance lease, weighted average discount rate, percent	1.56%

NOTES PAYABLE AND LEASE OBLIG_8

NOTES PAYABLE AND LEASE OBLIGATIONS - Summary of Lines of Credit (Details) - 3 months ended Mar. 31, 2019 ¥ in Millions, $ in Millions	USD ($)	JPY (¥)
$100 million line of credit
Line of Credit Facility [Line Items]
Line of credit facility, interest rate description	The rate quoted by the bank and agreed upon at the time of borrowing
Line of credit facility term	364 days
Line of credit facility, maximum borrowing capacity | $	$ 100
Line of credit facility, amount outstanding | $	$ 0
100.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, interest rate description	A rate per annum equal to (a) Tokyo interbank market rate (TIBOR) plus, the alternative applicable TIBOR margin during the availability period from the closing date to the commitment termination date or (b) the TIBOR rate offered by the agent to major banks in yen for the applicable period plus, the applicable alternative TIBOR margin during the term out period
Line of credit facility term	5 years
Line of credit facility, maximum borrowing capacity | ¥		¥ 100,000
Line of credit facility, amount outstanding | ¥		0
55.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, interest rate description	A rate per annum equal to, at the Company's option, either, (a) London Interbank Offered Rate (LIBOR) adjusted for certain costs or (b) a base rate determined by reference to the highest of (1) the federal funds rate plus 1/2 of 1%, (2) the rate of interest for such day announced by Mizuho Bank, Ltd. as its prime rate, or (3) the eurocurrency rate for an interest period of one month plus 1.00%, in each case plus an applicable margin
Line of credit facility term	5 years
Line of credit facility, maximum borrowing capacity | ¥		55,000
Line of credit facility, amount outstanding | ¥		0
$50 million line of credit
Line of Credit Facility [Line Items]
Line of credit facility, interest rate description	A rate per annum equal to, at the Parent Company's option, either (a) a eurocurrency rate determined by reference to the agent's LIBOR for the interest period relevant to such borrowing or (b) the base rate determined by reference to the greater of (i) the prime rate as determined by the agent, and (ii) the sum of 0.50% and the federal funds rate for such day
Line of credit facility, maximum borrowing capacity | $	$ 50
Line of credit facility, amount outstanding | $	$ 0
$250 million line of credit
Line of Credit Facility [Line Items]
Line of credit facility, interest rate description	USD three-month LIBOR plus 75 basis points per annum
Line of credit facility term	364 days
Line of credit facility, maximum borrowing capacity | $	$ 250
Line of credit facility, amount outstanding | $	$ 0
Debt instrument, term	3 months
50.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, interest rate description	Three-month TIBOR plus 80 basis points per annum
Line of credit facility term	364 days
Line of credit facility, maximum borrowing capacity | ¥		50,000
Line of credit facility, amount outstanding | ¥		¥ 0
Debt instrument, term	3 months
Lower Limit | 100.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.30%
Lower Limit | 55.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.085%
Upper Limit | $100 million line of credit
Line of Credit Facility [Line Items]
Debt instrument, term	3 months
Upper Limit | 100.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.50%
Upper Limit | 55.0 billion yen line of credit
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.225%
Upper Limit | $50 million line of credit
Line of Credit Facility [Line Items]
Debt instrument, term	3 months

SHAREHOLDERS' EQUITY - Reconcil

SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Common Stock Issued [Roll Forward]
Balance, beginning of period	1,347,540	1,345,762
Exercise of stock options and issuance of restricted shares	1,060	1,014
Balance, end of period	1,348,600	1,346,776
Treasury Stock [Roll Forward]
Balance, beginning of period	592,254	564,852
Balance, end of period	602,113	571,019
Shares outstanding, end of period	746,487	775,757
Treasury Stock
Treasury Stock [Roll Forward]
Stock acquired in open market, shares	10,237	6,640
Other purchases	561	315
Shares issued to AFL Stock Plan	(430)	(384)
Exercise of stock options	(231)	(305)
Other dispositions	(278)	(99)

SHAREHOLDERS' EQUITY - Anti-Dil

SHAREHOLDERS' EQUITY - Anti-Dilutive Share-Based Awards Excluded from Calculation of Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Anti-dilutive share-based awards	22	9

SHAREHOLDERS' EQUITY - Addition

SHAREHOLDERS' EQUITY - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders Equity Note [Line Items]
Common stock, share repurchase, dollar amount	$ 490	$ 296
Remaining common stock available for purchase under share repurchase authorizations	58.8
Share Repurchase Program
Stockholders Equity Note [Line Items]
Stock acquired in open market, shares	10.2	6.6
Common stock, share repurchase, dollar amount	$ 490	$ 296

SHAREHOLDERS' EQUITY - Changes

SHAREHOLDERS' EQUITY - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018		Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative effect of change in accounting principle, net of income taxes	[1]				$ 0
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period		$ 2,151	$ 4,028
Other comprehensive income (loss) before reclassifications net of tax		2,340	(571)
Amounts reclassified from accumulated other comprehensive income net of tax		(10)	228
Other comprehensive income (loss), net of tax		2,330	(343)
Balance, end of period		4,481	3,685
Accumulated other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative effect of change in accounting principle, net of income taxes	[1]				$ 226
Accumulated other comprehensive income (loss) | Accounting Standards Update 2016-01
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative effect of change in accounting principle, net of income taxes			(148)
Accumulated other comprehensive income (loss) | Accounting Standards Update 2018-02
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative effect of change in accounting principle, net of income taxes			374
Unrealized foreign currency translation gains (losses)
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period		(1,847)	(1,750)
Other comprehensive income (loss) before reclassifications net of tax		(1)	447
Amounts reclassified from accumulated other comprehensive income net of tax		0	0
Other comprehensive income (loss), net of tax		(1)	447
Balance, end of period		(1,848)	(1,303)
Unrealized gains (losses) on investment securities
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period		4,234	5,964
Other comprehensive income (loss) before reclassifications net of tax		2,340	(983)
Amounts reclassified from accumulated other comprehensive income net of tax		(13)	225	[2]
Other comprehensive income (loss), net of tax		2,327	(758)
Balance, end of period		6,561	5,206
Unrealized gains (losses) on derivatives
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period		(24)	(23)
Other comprehensive income (loss) before reclassifications net of tax		(2)	2
Amounts reclassified from accumulated other comprehensive income net of tax		0	0
Other comprehensive income (loss), net of tax		(2)	2
Balance, end of period		(26)	(21)
Pension liability adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period		(212)	(163)
Other comprehensive income (loss) before reclassifications net of tax		3	(37)
Amounts reclassified from accumulated other comprehensive income net of tax		3	3
Other comprehensive income (loss), net of tax		6	(34)
Balance, end of period		$ (206)	$ (197)
[1]	See Note 1 of the Notes to the Consolidated Financial Statements in the Company's 2018 Annual Report on Form 10-K
[2]	Includes amounts reclassified due to changes in accounting principles of $(148) related to financial instruments and $374 related to

SHAREHOLDERS' EQUITY - Reclassi

SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other-than-temporary impairment losses realized		$ (2)		$ (7)
Other gains (losses)		73		(127)
Total before tax		1,242		982
Income tax (expense) or benefit		(314)		(265)
Net of tax		$ 928		$ 717
Blended statutory income tax rate		25.00%		27.00%
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		$ 10		$ (2)
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized gains (losses) on investment securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other-than-temporary impairment losses realized		0		0
Other gains (losses)		17		2
Total before tax		17		2
Income tax (expense) or benefit		(4)	[1]	(1)	[2]
Net of tax		13		1
Reclassification Out Of Accumulated Other Comprehensive Income | Pension liability adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Acquisition and operating expenses, actuarial gains (losses)	[3]	(4)		(4)
Acquisition and operating expenses, prior service (cost) credit	[3]	0		0
Income tax (expense) or benefit		1	[1]	1	[2]
Net of tax		$ (3)		$ (3)
[1]	Based on 25%
[2]	Based on 27%
[3]	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 11 for additional details).

SHARE-BASED COMPENSATION - Addi

SHARE-BASED COMPENSATION - Additional Information (Detail) - USD ($) shares in Thousands, $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock options exercised		$ 17	$ 23
Tax benefit from exercise of stock options		$ 22	$ 12
Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, maximum number of shares issuable		75,000
Share-based compensation arrangement by share-based payment award, maximum number of shares issuable other than options and stock appreciation rights		38,000
Shares available for future grants under the long-term incentive plan		39,400
Long-term incentive plan awards, term (in years)		10 years
Long-term incentive plan awards, vesting period		3 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost not yet recognized, restricted stock awards		$ 70
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number, shares		2,597		3,407
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition		1 year 4 months 24 days
Restricted stock awards, grants in period		940
Performance based Vesting Condition | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost not yet recognized, restricted stock awards		$ 33
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number, shares		824
Restricted stock awards, grants in period	399

SHARE-BASED COMPENSATION - Stoc

SHARE-BASED COMPENSATION - Stock Options Outstanding and Exercisable (Detail) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options Outstanding - Stock Option Shares | shares	4,558
Options Outstanding - Weighted-Average Remaining Term (Yrs)	5 years
Options Outstanding - Aggregate Intrinsic Value | $	$ 94
Options Outstanding - Weighted-Average Exercise Price Per Share | $ / shares	$ 29.36
Options Exercisable - Stock Option Shares | shares	4,097
Options Exercisable - Weighted-Average Remaining Term (Yrs.)	4 years 7 months 6 days
Options Exercisable - Aggregate Intrinsic Value | $	$ 88
Options Exercisable - Weighted-Average Exercise Price Per Share | $ / shares	$ 28.54

SHARE-BASED COMPENSATION - Rest

SHARE-BASED COMPENSATION - Restricted Stock Activity (Details) - Restricted Stock shares in Thousands	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Shares
Beginning Balance | shares	3,407
Granted | shares	940
Canceled | shares	(18)
Vested | shares	(1,732)
Ending Balance | shares	2,597
Weighted-Average Grant-Date Fair Value Per Share
Beginning Balance | $ / shares	$ 36.52
Granted | $ / shares	49.17
Cancelled | $ / shares	37.98
Vested | $ / shares	32.16
Ending Balance | $ / shares	$ 44.02

BENEFIT PLANS - Additional Info

BENEFIT PLANS - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amount of years active employees have left to meet rule of 80 in order to be eligible for postretirement medical benefits			5 years
Amount of years left to meet 15 year service requirement for active employees age 55 or older to be eligible for postretirement medical benefits			5 years
Net periodic (benefit) cost, excluding service cost	$ 5	$ 5
Lower Limit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Health care plan, retirement age and years of service combined years for eligibility (rule of 80)			80 years
Health care plan, retirement age for eligibility, (in years)			55 years
Health care plan, number of years of service for eligibility			15 years
Japan | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	9
U.S. | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 10

BENEFIT PLANS - Net Periodic (B

BENEFIT PLANS - Net Periodic (Benefit) Cost Included in Acquisition and Operating Expenses (Detail) - Pension Plan - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Japan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 5	$ 5
Interest cost	1	2
Expected return on plan assets	(2)	(2)
Amortization of net actuarial loss	1	0
Net periodic (benefit) cost	5	5
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6	7
Interest cost	9	9
Expected return on plan assets	(7)	(7)
Amortization of net actuarial loss	3	4
Net periodic (benefit) cost	$ 11	$ 13

COMMITMENTS AND CONTINGENT LI_2

COMMITMENTS AND CONTINGENT LIABILITIES - Additional Information (Details) $ in Millions, ¥ in Billions	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2019JPY (¥)	Mar. 31, 2017USD ($)
Commitments And Contingencies Disclosure [Line Items]
Loss contingency accrual, insurance-related assessment, discount rate			4.25%
Loss contingency, discounted amount of insurance-related assessment liability			$ 62
Loss contingency, undiscounted amount of insurance-related assessment liability			94
Loss contingency, insurance-related assessment, discounted amount of premium tax offset			48
Loss contingency, insurance-related assessment, undiscounted amount of premium tax offset			74
Loss contingency, loss in period			$ 14
Information technology and data services company application maintenance and development services first agreement
Commitments And Contingencies Disclosure [Line Items]
Outsourcing agreements, remaining term	5 years	5 years
Outsourcing agreements, aggregate remaining cost	$ 87	¥ 9.7

SUBSEQUENT EVENTS Additional In

SUBSEQUENT EVENTS Additional Information (Detail) - Perpetual subordinated bonds - Subsequent events ¥ in Billions	Apr. 12, 2019JPY (¥)
Subsequent Event [Line Items]
Debt instrument, principal amount	¥ 30
Debt instrument, interest rate	0.963%
Debt instrument, description of variable rate basis	These bonds will bear interest at a fixed rate of .963% per annum and then at six-month Euro Yen LIBOR plus an applicable spread on and after the day immediately following April 18, 2024.