Aflac (AFL) 10-Q 2 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 25, 2017
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	AFL
Entity Registrant Name	AFLAC INC
Entity Central Index Key	4,977
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		393,149,620

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Net premiums, principally supplemental health insurance	$ 4,648	$ 5,022	$ 13,951	$ 14,447
Net investment income	811	842	2,408	2,465
Realized investment gains (losses):
Other-than-temporary impairment losses realized	(8)	(23)	(27)	(71)
Sales and redemptions	61	(14)	60	100
Derivative and other gains (losses)	(23)	(127)	(199)	(387)
Total realized investment gains (losses)	30	(164)	(166)	(358)
Other income (loss)	17	16	50	50
Total revenues	5,506	5,716	16,243	16,604
Benefits and expenses:
Benefits and claims, net	3,083	3,378	9,174	9,657
Acquisition and operating expenses:
Amortization of deferred policy acquisition costs	271	282	848	858
Insurance commissions	332	353	996	1,031
Insurance and other expenses	686	675	2,025	1,948
Interest expense	59	65	181	196
Total acquisition and operating expenses	1,348	1,375	4,050	4,033
Total benefits and expenses	4,431	4,753	13,224	13,690
Earnings before income taxes	1,075	963	3,019	2,914
Income taxes	359	334	998	1,006
Net earnings	$ 716	$ 629	$ 2,021	$ 1,908
Net earnings per share:
Basic (in dollars per share)	$ 1.81	$ 1.54	$ 5.09	$ 4.62
Diluted (in dollars per share)	$ 1.80	$ 1.53	$ 5.05	$ 4.59
Weighted-average outstanding common shares used in computing earnings per share (In thousands):
Basic (in shares)	394,479	408,519	397,323	413,023
Diluted (in shares)	397,381	411,140	400,241	415,446
Cash dividends per share	$ 0.43	$ 0.41	$ 1.29	$ 1.23

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net earnings		$ 716	$ 629	$ 2,021	$ 1,908
Other comprehensive income (loss) before income taxes:
Unrealized foreign currency translation gains (losses) during period		(58)	195	325	1,783
Unrealized gains (losses) on investment securities:
Unrealized holding gains (losses) on investment securities during period		457	(527)	1,006	4,855
Reclassification adjustment for realized (gains) losses on investment securities included in net earnings		(50)	33	(33)	(33)
Unrealized gains (losses) on derivatives during period		(1)	0	0	11
Pension liability adjustment during period		1	0	(1)	(6)
Total other comprehensive income (loss) before income taxes		349	(299)	1,297	6,610
Income tax expense (benefit) related to items of other comprehensive income (loss)		219	(231)	396	1,871
Other comprehensive income (loss), net of income taxes	[1]	130	(68)	901	4,739
Total comprehensive income (loss)		$ 846	$ 561	$ 2,922	$ 6,647
[1]	All amounts in the table above are net of tax.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Securities held to maturity, at amortized cost:
Fixed maturities		$ 31,998	$ 33,350
Other Investments	[1]	2,358	1,450
Cash and cash equivalents		4,927	4,859
Total investments and cash		122,489	116,361
Receivables		937	669
Accrued investment income		730	754
Deferred policy acquisition costs		9,413	8,993
Property and equipment, at cost less accumulated depreciation		439	433
Other	[2]	2,075	2,609
Total assets		136,083	129,819
Policy Liabilities:
Future policy benefits		81,116	76,106
Unpaid policy claims		4,368	4,045
Unearned premiums		6,262	6,916
Other policyholders’ funds		6,967	6,659
Total policy liabilities		98,713	93,726
Income Taxes		6,195	5,387
Payables for return of cash collateral on loaned securities		522	526
Notes payable		5,248	5,360
Other	[3]	3,428	4,338
Total liabilities		114,106	109,337
Shareholders’ equity:
Common stock of $.10 par value. In thousands: authorized 1,900,000 shares in 2017 and 2016; issued 672,669 shares in 2017 and 671,249 shares in 2016		67	67
Additional paid-in capital		2,077	1,976
Retained earnings		27,489	25,981
Accumulated other comprehensive income (loss):
Unrealized foreign currency translation gains (losses)		(1,715)	(1,983)
Unrealized gain (losses) on investment securities		5,437	4,805
Unrealized gains (losses) on derivatives		(23)	(24)
Pension liability adjustment		(168)	(168)
Treasury stock, at average cost		(11,187)	(10,172)
Total shareholders’ equity		21,977	20,482
Total liabilities and shareholders’ equity		136,083	129,819
Variable Interest Entity, Consolidated
Securities available for sale, at fair value:
Fixed maturities		5,224	4,982
Perpetual securities		211	208
Equity securities		690	1,044
Securities held to maturity, at amortized cost:
Other Investments	[4]	1,500	819
Policy Liabilities:
Total liabilities		132	146
Investments Other Than Consolidated Variable Interest Entities
Securities available for sale, at fair value:
Fixed maturities		75,191	68,778
Perpetual securities		1,652	1,425
Equity securities		238	265
Securities held to maturity, at amortized cost:
Fixed maturities		$ 31,998	$ 33,350
[1]	Includes $1,500 in 2017 and $819 in 2016 of loan receivables and limited partnerships from consolidated variable interest entities
[2]	Includes $148 in 2017 and $127 in 2016 of derivatives from consolidated variable interest entities
[3]	Includes $132 in 2017 and $146 in 2016 of derivatives from consolidated variable interest entities
[4]	Consists of CMLs, MMLs, and alternative investments in limited partnerships

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Securities held to maturity, fixed maturities, fair value		$ 38,599	$ 40,021
Common stock, par value (in dollars per share)		$ 0.1	$ 0.1
Common stock, shares authorized (in shares)		1,900,000,000	1,900,000,000
Common stock, shares issued (in shares)		672,669,000	671,249,000
Asset derivatives		$ 479	$ 1,207
Liability derivatives		974	1,998
Variable Interest Entity, Consolidated
Securities available for sale, fixed maturities, amortized cost		4,274	4,168
Securities available for sale, perpetual securities, amortized cost		239	237
Securities available for sale, equity securities, cost		595	972
Asset derivatives	[1]	148	127
Liability derivatives	[1]	132	146
Investments Other Than Consolidated Variable Interest Entities
Securities available for sale, fixed maturities, amortized cost		67,970	62,195
Securities available for sale, perpetual securities, amortized cost		1,310	1,269
Securities available for sale, equity securities, cost		216	231
Securities held to maturity, fixed maturities, fair value		38,599	40,021
Loan Receivables and Limited Partnerships | Variable Interest Entity, Consolidated
Other investments held in unit trust, net of reserves, amortized cost		$ 1,500	$ 819
[1]	Consists entirely of derivatives

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:
Balance, beginning of period at Dec. 31, 2015		$ 67	$ 1,828	$ 24,007	$ 625	$ (8,819)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options			38
Share-based compensation			41
Net earnings	$ 1,908			1,908
Dividends to shareholders				(511)
Unrealized foreign currency translation gains (losses) during period, net of income taxes					1,602
Unrealized gains (losses) on investment securities during period, net of income taxes and reclassification adjustments					3,134
Unrealized gains (losses) on derivatives during period, net of income taxes					7
Pension liability adjustment during period, net of income taxes					(4)
Purchases of treasury stock						(1,222)
Treasury stock reissued			29			55
Balance, end of period at Sep. 30, 2016	22,785	67	1,936	25,404	5,364	(9,986)
Balance, beginning of period at Dec. 31, 2016	20,482	67	1,976	25,981	2,630	(10,172)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options			33
Share-based compensation			38
Net earnings	2,021			2,021
Dividends to shareholders				(513)
Unrealized foreign currency translation gains (losses) during period, net of income taxes					268
Unrealized gains (losses) on investment securities during period, net of income taxes and reclassification adjustments					632
Unrealized gains (losses) on derivatives during period, net of income taxes					1
Pension liability adjustment during period, net of income taxes					0
Purchases of treasury stock						(1,053)
Treasury stock reissued			30			38
Balance, end of period at Sep. 30, 2017	$ 21,977	$ 67	$ 2,077	$ 27,489	$ 3,531	$ (11,187)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net earnings	$ 2,021	$ 1,908
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in receivables and advance premiums	(32)	41
Increase in deferred policy acquisition costs	(229)	(186)
Increase in policy liabilities	2,137	2,329
Change in income tax liabilities	323	(365)
Realized investment (gains) losses	166	358
Other, net	210	35
Net cash provided (used) by operating activities	4,596	4,120
Securities available for sale:
Fixed maturities sold	2,633	978
Fixed maturities matured or called	740	774
Perpetual securities matured or called	9	234
Equity securities sold	755	173
Securities held to maturity:
Fixed maturities matured or called	1,714	946
Costs of investments acquired:
Available for sale fixed maturities acquired	(6,827)	(4,871)
Available for sale equity securities acquired	(391)	(868)
Other investments, net	(949)	(801)
Settlement of derivatives, net	(240)	1,203
Cash received (pledged or returned) as collateral, net	(273)	(350)
Other, net	(58)	(56)
Net cash provided (used) by investing activities	(2,887)	(2,638)
Cash flows from financing activities:
Purchases of treasury stock	(1,053)	(1,222)
Proceeds from borrowings	524	988
Principal payments under debt obligations	(660)	(232)
Dividends paid to shareholders	(491)	(492)
Change in investment-type contracts, net	39	117
Treasury stock reissued	23	37
Other, net	5	(31)
Net cash provided (used) by financing activities	(1,613)	(835)
Effect of exchange rate changes on cash and cash equivalents	(28)	273
Net change in cash and cash equivalents	68	920
Cash and cash equivalents, beginning of period	4,859	4,350
Cash and cash equivalents, end of period	4,927	5,270
Supplemental disclosures of cash flow information:
Income taxes paid	693	1,594
Interest paid	144	155
Noncash interest	38	41
Impairment losses included in realized investment losses	27	71
Capital lease obligations incurred	7	2
Associate stock bonus
Treasury stock issued for:
Treasury stock issued	22	24
Shareholder dividend reinvestment
Treasury stock issued for:
Treasury stock issued	22	19
Share-based compensation grants
Treasury stock issued for:
Treasury stock issued	$ 1	$ 4

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2017
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), which operates in the United States (Aflac U.S.) and as a branch in Japan (Aflac Japan). 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 its branch in 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 69% and 74% of the Company's total revenues in the nine -month periods ended September 30, 2017 and 2016 , respectively. The percentage of the Company's total assets attributable to Aflac Japan was 83% at both September 30, 2017 , and December 31, 2016 . Basis of Presentation The Company prepares its financial statements in accordance with U.S. generally accepted accounting principles (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 September 30, 2017 , and December 31, 2016 , the consolidated statements of earnings and comprehensive income (loss) for the three- and nine -month periods ended September 30, 2017 and 2016 , and the consolidated statements of shareholders' equity and cash flows for the nine -month periods ended September 30, 2017 and 2016 . 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, 2016 (2016 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. Prior year foreign currency transaction gains and losses have been reclassified from Other income (loss) to Realized investment gains (losses) - Derivative and other gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on net earnings or total shareholders' equity. This change in classification was made to reflect that the major source of the Company's foreign currency transaction gains and losses is directly or indirectly a result of its investment activity. New Accounting Pronouncements Recently Adopted Accounting Pronouncements Consolidation - Interests Held through Related Parties That Are under Common Control: In October 2016, the FASB issued amendments which clarify the consolidation guidance on how a reporting entity that is the single decision maker of a variable interest entity (VIE) should treat indirect interests in the entity held through related parties that are under common control with the reporting entity when determining whether it is the primary beneficiary of that VIE. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Compensation - Stock Compensation - Improvements to Employee Share-Based Payment Accounting: In March 2016, the FASB issued amendments which simplify several aspects for share-based payment award transactions, including income tax consequences, classification of awards as either liability or equity, and classification on the statement of cash flows. The Company adopted this guidance as of January 1, 2017. The amendment requires prospective recognition of excess tax benefits and deficiencies in the income statement, rather than in paid-in capital. As a result of applying this requirement, the Company believes that recognition of excess tax benefits will increase volatility in its statement of operations, but the adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. The amendment also requires all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) to be recognized as income tax expense or benefit in the income statement. The guidance requires modified retrospective transition for settlements on all outstanding awards (both historical and future) that did not give rise to an excess benefit to be recorded through retained earnings on a cumulative-effect basis. The adoption of these amendments in the guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Additionally, the amendment requires that the minimum statutory tax withholding for all outstanding liability awards be reclassified at the date of adoption to equity (assuming equity classification results from the guidance change), and as a cumulative-effect adjustment to equity be recorded on a modified retrospective basis. The adoption of these amendments in the guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. The guidance requires certain reclassifications of balances on the statement of cash flows to or from operating and financing activities. The reclassification guidance did not have a significant impact on the Company's statement of cash flows. The amendment allows an entity to elect whether to use estimates of forfeitures, or to account for forfeitures as they occur, using modified retrospective application. The Company made an entity-wide accounting policy election to estimate the number of awards that are expected to vest (consistent with the Company's prior policy) . The election and adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Investments - Equity Method and Joint Ventures - Simplifying the Transition to the Equity Method of Accounting: In March 2016, the FASB issued amendments which eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. Per the amendments, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendments also require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Derivatives and Hedging - Contingent Put and Call Options in Debt Instruments: In March 2016, the FASB issued amendments which clarify what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts, which is one of the criteria for bifurcating an embedded derivative. Consequently, when a call (put) option is contingently exercisable, an entity does not have to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Derivatives and Hedging - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships: In March 2016, the FASB issued amendments which clarify that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria remain intact. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Accounting Pronouncements Pending Adoption Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities: In August 2017, FASB issued guidance which improves and simplifies the accounting rules around hedge accounting and will create more transparency around how economic results are presented on financial statements. Issues addressed in this new guidance include: 1) risk component hedging, 2) accounting for the hedged item in fair value hedges of interest rate risk, 3) recognition and presentation of the effects of hedging instruments, and 4) amounts excluded from the assessment of hedge effectiveness. The amendments are effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted in any interim period after issuance of the guidance. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Compensation-Stock Compensation: Scope of Modification Accounting: In May 2017, the FASB issued amendments to provide guidance clarifying when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. An entity should apply modification accounting if the fair value, vesting conditions or classification of the award (as an equity instrument or liability instrument) changes as a result of the change in terms or conditions of the award. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted and should be applied prospectively. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Receivables-Nonrefundable Fees and Other Costs: Premium Amortization on Purchased Callable Debt Securities: In March 2017, the FASB issued amendments to shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount. The amendments are effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Compensation-Retirement Benefit: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost: In March 2017, the FASB issued amendments requiring that an employer report the service cost component of net periodic pension cost and net periodic postretirement benefit cost in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net periodic pension cost and net periodic postretirement benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. If a separate line item or items are used to present the other components of net benefit cost, that line item or items must be appropriately described. If a separate line item or items are not used, the line item or items used in the income statement to present the other components of net benefit cost must be disclosed. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. 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, disclosures, or statements of cash flows. Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets - Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets: In February 2017, the FASB issued amendments that clarify the scope and accounting guidance for the derecognition of a nonfinancial asset or a financial asset that meets the definition of an "in substance nonfinancial asset." The amendments define an "in substance nonfinancial asset" and provide additional accounting guidance for partial sales of nonfinancial assets. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Earlier adoption is permitted for fiscal years beginning after December 15, 2016, including interim periods therein. An entity is required to apply the amendments at the same time that it applies the FASB amendments for Revenue from Contracts with Customers. The Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, disclosures, and statements of cash flows. 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 U.S. Securities and Exchange Commission (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 Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, or disclosures. Business Combinations - Clarifying the Definition of a Business: In January 2017, the FASB issued amendments clarifying when a set of assets and activities is a business. The amendments provide a screen to exclude transactions where substantially all the fair value of the transferred set is concentrated in a single asset, or group of similar assets, from being evaluated as a business. The amendments are effective for public business entities beginning after December 15, 2017, including interim periods within those periods. The Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, or disclosures. Statement of Cash Flows - Restricted Cash: In November 2016, the FASB issued amendments requiring that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, disclosures, or statement of cash flows. Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory: In October 2016, the FASB issued amendments that require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments are effective for public business entities for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. Early adoption is permitted. The Company is evaluating the impact of adoption of this guidance on its financial position, results of operations, and disclosures. Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payment s: In August 2016, the FASB issued amendments that provide guidance on eight specific statement of cash flows classification issues. The amendments are effective for public companies for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted for any interim or annual period. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, disclosures, or statements of cash flows. 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 writedown. 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. 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 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 continues to evaluate the impact of adoption of this guidance on its financial position, results of operations, and disclosures. Leases: In February 2016, the FASB issued updated guidance for accounting for leases. Per the amendments, lessees will be 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. A right-of-use asset will be recorded which represents the lessee’s right to use, or to control the use of, a specified asset for a lease term. Under the new guidance, lessor accounting is largely unchanged. The amendments are effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company has identified certain operating leases in scope of this guidance to include office space and equipment leases (See Note 15 of the Notes to the Consolidated Financial Statements in the 2016 Annual Report for current balances of leases in scope). The leases within scope of this guidance will increase the Company's right-of-use assets and lease liabilities recorded on its statement of financial position, however the Company estimates leases within scope of the guidance to represent less than 1% of its total assets as of September 30, 2017 . The Company estimates that the adoption of this guidance will not have a significant impact on its financial position, results of operations, and disclosures. Financial Instruments - Overall - Recognition and Measurement of Financial Assets and Financial Liabilities: In January 2016, the FASB issued guidance to address certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. The main provisions require that equity investments be measured at fair value with changes recognized in net income; that changes in instrument-specific credit risk for financial liabilities that are measured under the fair value option be recognized in other comprehensive income; and that entities would make the assessment of the ability to realize a deferred tax asset (DTA) related to an available-for-sale (AFS) debt security in combination with the entity's other DTAs. The amendments are effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is not permitted, with the exception of the own credit provision if an entity has elected to measure a liability at fair value. The Company has identified certain financial instruments in scope of this guidance to include certain fixed maturity securities, perpetual securities and equity securities (See Note 3 for current balances of instruments in scope). The Company estimates that the impact of this guidance will increase volatility in its statement of operations and the Company continues to evaluate the impact of this guidance on its statement of financial position, results of operations, and disclosures. Revenue from Contracts with Customers: In May 2014, the FASB issued updated guidance that affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (e.g., insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB deferred the effective date for this standard to annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods. The Company has identified revenue in scope of this guidance to include certain revenues associated with affiliated entities in support of its operations. The Company estimates the revenue within scope of the guidance to represent less than 1% of its total revenues as of September 30, 2017 . The Company estimates that the adoption of this guidance will not have a significant impact 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 2016 Annual Report.

BUSINESS SEGMENT INFORMATION

BUSINESS SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2017
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. Operating business segments that are not individually reportable and business activities, including reinsurance retrocession activities, not included in Aflac Japan or Aflac U.S. are included in the "Other business segments" category. 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 operating earnings. The Company's definition of operating earnings includes interest cash flows associated with notes payable and amortized hedge costs related to foreign currency denominated investments, but excludes certain items that cannot be predicted or that are outside of management's control, such as realized investment gains and losses from securities transactions, impairments, change in loan loss reserves and certain derivative and foreign currency activities; nonrecurring items; and other non-operating income (loss) from net earnings. Nonrecurring and other non-operating items consist of infrequent events and activity not associated with the normal course of the Company’s insurance operations and do not reflect Aflac’s underlying business performance. The Company excludes income taxes related to operations to arrive at pretax operating earnings. Information regarding operations by segment follows: Three Months Ended Nine Months Ended (In millions) 2017 2016 2017 2016 Revenues: Aflac Japan: Net earned premiums $ 3,200 $ 3,596 $ 9,616 $ 10,177 Net investment income, less amortized hedge costs (1) 561 607 1,676 1,802 Other income 11 10 31 29 Total Aflac Japan 3,772 4,213 11,323 12,008 Aflac U.S.: Net earned premiums 1,393 1,365 4,172 4,093 Net investment income 181 176 539 526 Other income 1 1 3 5 Total Aflac U.S. 1,575 1,542 4,714 4,624 Other business segments 69 71 204 207 Total business segment revenues 5,416 5,826 16,241 16,839 Corporate and eliminations 19 20 59 63 Total operating revenues 5,435 5,846 16,300 16,902 Realized investment gains (losses) (1), (2), (3) 71 (130 ) (57 ) (298 ) Total revenues $ 5,506 $ 5,716 $ 16,243 $ 16,604 (1) Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from net investment income when analyzing segment operations to conform to current year reporting. (2) Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations (3) Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total revenues. Three Months Ended Nine Months Ended (In millions) 2017 2016 2017 2016 Pretax earnings: Aflac Japan (1) $ 748 $ 827 $ 2,308 $ 2,436 Aflac U.S. 316 323 956 946 Other business segments 5 4 9 12 Total business segment pretax operating earnings 1,069 1,154 3,273 3,394 Interest expense, noninsurance operations (30 ) (31 ) (89 ) (90 ) Corporate and eliminations (25 ) (31 ) (70 ) (91 ) Pretax operating earnings 1,014 1,092 3,114 3,213 Realized investment gains (losses) (1), (2), (3) 71 (130 ) (57 ) (298 ) Other non-operating income (loss) (3) (10 ) 1 (38 ) (1 ) Total earnings before income taxes $ 1,075 $ 963 $ 3,019 $ 2,914 Income taxes applicable to pretax operating earnings $ 338 $ 379 $ 1,031 $ 1,112 Effect of foreign currency translation on after-tax (29 ) 61 (31 ) 110 (1) Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from pretax operating earnings when analyzing segment operations to conform to current year reporting. (2) Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations (3) Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total earnings before income taxes. Assets were as follows: (In millions) September 30, December 31, Assets: Aflac Japan $ 113,625 $ 107,858 Aflac U.S. 20,348 19,453 Other business segments 513 270 Total business segment assets 134,486 127,581 Corporate and eliminations 1,597 2,238 Total assets $ 136,083 $ 129,819

INVESTMENTS

INVESTMENTS	9 Months Ended
	Sep. 30, 2017
Investments [Abstract]
INVESTMENTS	INVESTMENTS Investment Holdings The amortized cost for the Company's investments in debt and perpetual securities, the cost for equity securities and the fair values of these investments are shown in the following tables. September 30, 2017 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value: Fixed maturities: Yen-denominated: Japan government and agencies $ 27,027 $ 3,272 $ 423 $ 29,876 Municipalities 315 26 15 326 Mortgage- and asset-backed securities 248 29 0 277 Public utilities 1,643 369 7 2,005 Sovereign and supranational 1,428 190 3 1,615 Banks/financial institutions 3,307 494 59 3,742 Other corporate 3,811 771 25 4,557 Total yen-denominated 37,779 5,151 532 42,398 U.S. dollar-denominated: U.S. government and agencies 150 12 0 162 Municipalities 818 148 0 966 Mortgage- and asset-backed securities 166 13 0 179 Public utilities 5,231 813 34 6,010 Sovereign and supranational 325 89 0 414 Banks/financial institutions 2,683 592 7 3,268 Other corporate 25,092 2,388 462 27,018 Total U.S. dollar-denominated 34,465 4,055 503 38,017 Total fixed maturities 72,244 9,206 1,035 80,415 Perpetual securities: Yen-denominated: Banks/financial institutions 1,308 277 32 1,553 Other corporate 195 41 0 236 U.S. dollar-denominated: Banks/financial institutions 46 28 0 74 Total perpetual securities 1,549 346 32 1,863 Equity securities: Yen-denominated 555 95 2 648 U.S. dollar-denominated 256 30 6 280 Total equity securities 811 125 8 928 Total securities available for sale $ 74,604 $ 9,677 $ 1,075 $ 83,206 September 30, 2017 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturities: Yen-denominated: Japan government and agencies $ 21,385 $ 5,070 $ 0 $ 26,455 Municipalities 359 104 0 463 Mortgage- and asset-backed securities 27 2 0 29 Public utilities 3,308 426 0 3,734 Sovereign and supranational 1,527 319 0 1,846 Banks/financial institutions 2,700 205 18 2,887 Other corporate 2,692 493 0 3,185 Total yen-denominated 31,998 6,619 18 38,599 Total securities held to maturity $ 31,998 $ 6,619 $ 18 $ 38,599 December 31, 2016 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value: Fixed maturities: Yen-denominated: Japan government and agencies $ 22,857 $ 3,359 $ 160 $ 26,056 Municipalities 246 29 8 267 Mortgage- and asset-backed securities 1,096 33 8 1,121 Public utilities 1,533 318 3 1,848 Sovereign and supranational 862 186 5 1,043 Banks/financial institutions 2,673 403 74 3,002 Other corporate 3,192 623 3 3,812 Total yen-denominated 32,459 4,951 261 37,149 U.S dollar-denominated: U.S. government and agencies 148 10 0 158 Municipalities 894 142 8 1,028 Mortgage- and asset-backed securities 196 20 0 216 Public utilities 5,205 690 60 5,835 Sovereign and supranational 335 91 0 426 Banks/financial institutions 2,570 507 16 3,061 Other corporate 24,556 2,021 690 25,887 Total U.S. dollar-denominated 33,904 3,481 774 36,611 Total fixed maturities 66,363 8,432 1,035 73,760 Perpetual securities: Yen-denominated: Banks/financial institutions 1,266 128 49 1,345 Other corporate 189 24 0 213 U.S. dollar-denominated: Banks/financial institutions 51 24 0 75 Total perpetual securities 1,506 176 49 1,633 Equity securities: Yen-denominated 624 83 2 705 U.S. dollar-denominated 579 31 6 604 Total equity securities 1,203 114 8 1,309 Total securities available for sale $ 69,072 $ 8,722 $ 1,092 $ 76,702 December 31, 2016 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturities: Yen-denominated: Japan government and agencies $ 20,702 $ 5,338 $ 0 $ 26,040 Municipalities 350 107 0 457 Mortgage- and asset-backed securities 30 2 0 32 Public utilities 3,201 358 23 3,536 Sovereign and supranational 2,602 283 8 2,877 Banks/financial institutions 3,731 195 26 3,900 Other corporate 2,734 452 7 3,179 Total yen-denominated 33,350 6,735 64 40,021 Total securities held to maturity $ 33,350 $ 6,735 $ 64 $ 40,021 The methods of determining the fair values of the Company's investments in fixed-maturity securities, perpetual securities and equity securities are described in Note 5. During the third quarter of 2017, the Company did not reclassify any investments from the held-to-maturity category to the available-for-sale category. During the second quarter of 2017, the Company reclassified three investments from the held-to-maturity category to the available-for-sale category as a result of the issuers' credit rating being downgraded to below investment grade. At the time of the transfer, the securities had an amortized cost of $773 million and an unrealized gain of $47 million . During the first quarter of 2017, the Company did not reclassify any investments from the held-to-maturity category to the available-for-sale category. During the first nine months of 2016, 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 maturities of the Company's investments in fixed maturities at September 30, 2017 , were as follows: Aflac Japan Aflac U.S. (In millions) Amortized Fair Amortized Fair Available for sale: Due in one year or less $ 175 $ 181 $ 53 $ 54 Due after one year through five years 5,734 6,029 637 682 Due after five years through 10 years 9,078 9,668 3,253 3,529 Due after 10 years 43,860 49,502 8,443 9,698 Mortgage- and asset-backed securities 290 330 40 42 Total fixed maturities available for sale $ 59,137 $ 65,710 $ 12,426 $ 14,005 Held to maturity: Due in one year or less $ 488 $ 497 $ 0 $ 0 Due after one year through five years 923 970 0 0 Due after five years through 10 years 1,638 1,810 0 0 Due after 10 years 28,922 35,293 0 0 Mortgage- and asset-backed securities 27 29 0 0 Total fixed maturities held to maturity $ 31,998 $ 38,599 $ 0 $ 0 At September 30, 2017 , the Parent Company and other business segments had portfolios of available-for-sale fixed-maturity securities totaling $681 million at amortized cost and $700 million at fair value, which are not included in the table above. 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. The majority of the Company's perpetual securities are subordinated to other debt obligations of the issuer, but rank higher than the issuer's equity securities. Perpetual securities have characteristics of both debt and equity investments, along with unique features that create economic maturity dates for the securities. Although perpetual securities have no contractual maturity date, they have stated interest coupons that were fixed at their issuance and subsequently change to a floating short-term interest rate after some period of time. The instruments are generally callable by the issuer at the time of changing from a fixed coupon rate to a new variable rate of interest, which is determined by the combination of some market index plus a fixed amount of basis points. The net effect is to create an expected maturity date for the instrument. The economic maturities of the Company's investments in perpetual securities, which were all reported as available for sale at September 30, 2017 , were as follows: Aflac Japan Aflac U.S. (In millions) Amortized Fair Amortized Fair Due in one year or less $ 84 $ 85 $ 0 $ 0 Due after one year through five years 194 236 0 0 Due after 10 years 1,232 1,482 39 60 Total perpetual securities available for sale $ 1,510 $ 1,803 $ 39 $ 60 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: September 30, 2017 December 31, 2016 (In millions) Credit Amortized Fair Credit Amortized Fair Japan National Government (1) A $47,637 $55,444 A $42,931 $51,345 (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 Nine Months Ended (In millions) 2017 2016 2017 2016 Realized investment gains (losses): Fixed maturities: Available for sale: Gross gains from sales $ 10 $ 2 $ 27 $ 10 Gross losses from sales (8 ) (22 ) (38 ) (38 ) Net gains (losses) from redemptions 14 1 (24 ) 88 Other-than-temporary impairment losses (2 ) (1 ) (9 ) (23 ) Total fixed maturities 14 (20 ) (44 ) 37 Perpetual securities: Available for sale: Net gains (losses) from redemptions 0 0 4 40 Other-than-temporary impairment losses 0 0 0 (2 ) Total perpetual securities 0 0 4 38 Equity securities: Gross gains from sales 54 5 102 10 Gross losses from sales (9 ) 0 (11 ) (10 ) Other-than-temporary impairment losses (6 ) (22 ) (18 ) (46 ) Total equity securities 39 (17 ) 73 (46 ) Derivatives and other: Derivative gains (losses) (40 ) (107 ) (143 ) (278 ) Foreign currency gains (losses) 17 (20 ) (56 ) (109 ) Total derivatives and other (23 ) (127 ) (199 ) (387 ) Total realized investment gains (losses) $ 30 $ (164 ) $ (166 ) $ (358 ) Prior year foreign currency transaction gains and losses have been reclassified to conform to current-year reporting classifications Unrealized Investment Gains and Losses Effect on Shareholders’ Equity The net effect on shareholders’ equity of unrealized gains and losses from investment securities was as follows: (In millions) September 30, 2017 December 31, Unrealized gains (losses) on securities available for sale $ 8,602 $ 7,630 Deferred income taxes (3,165 ) (2,825 ) Shareholders’ equity, unrealized gains (losses) on investment securities $ 5,437 $ 4,805 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. September 30, 2017 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed Maturities: Japan government and Yen-denominated $ 6,404 $ 423 $ 6,208 $ 399 $ 196 $ 24 Municipalities: Yen-denominated 152 15 62 3 90 12 Public utilities: U.S. dollar-denominated 879 34 252 4 627 30 Yen-denominated 95 7 69 6 26 1 Sovereign and supranational: Yen-denominated 352 3 352 3 0 0 Banks/financial institutions: U.S. dollar-denominated 188 7 145 3 43 4 Yen-denominated 1,616 77 637 29 979 48 Other corporate: U.S. dollar-denominated 7,886 462 2,803 52 5,083 410 Yen-denominated 424 25 386 24 38 1 Total fixed maturities 17,996 1,053 10,914 523 7,082 530 Perpetual securities: Yen-denominated 340 32 0 0 340 32 Total perpetual securities 340 32 0 0 340 32 Equity securities: U.S. dollar-denominated 58 6 50 5 8 1 Yen-denominated 72 2 67 1 5 1 Total equity securities 130 8 117 6 13 2 Total $ 18,466 $ 1,093 $ 11,031 $ 529 $ 7,435 $ 564 December 31, 2016 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed Maturities: Japan government and Yen-denominated $ 3,958 $ 160 $ 3,958 $ 160 $ 0 $ 0 Municipalities: U.S. dollar-denominated 44 8 0 0 44 8 Yen-denominated 105 8 105 8 0 0 Mortgage- and asset- Yen-denominated 713 8 713 8 0 0 Public utilities: U.S. dollar-denominated 1,265 60 790 32 475 28 Yen-denominated 635 26 347 14 288 12 Sovereign and supranational: Yen-denominated 244 13 38 5 206 8 Banks/financial institutions: U.S. dollar-denominated 268 16 238 10 30 6 Yen-denominated 1,521 100 636 19 885 81 Other corporate: U.S. dollar-denominated 10,462 690 7,252 346 3,210 344 Yen-denominated 321 10 321 10 0 0 Total fixed maturities 19,536 1,099 14,398 612 5,138 487 Perpetual securities: Yen-denominated 479 49 85 1 394 48 Total perpetual securities 479 49 85 1 394 48 Equity securities: U.S. dollar-denominated 211 6 211 6 0 0 Yen-denominated 49 2 49 2 0 0 Total equity securities 260 8 260 8 0 0 Total $ 20,275 $ 1,156 $ 14,743 $ 621 $ 5,532 $ 535 Analysis of Securities in Unrealized Loss Positions The unrealized losses on the Company's fixed maturity or perpetual 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. The unrealized losses on the Company's investments in equity securities are primarily related to foreign exchange rates, general market conditions which reflect prospects for the economy as a whole, or specific information pertaining to an industry or an individual company. For any significant declines in fair value of its fixed income or perpetual 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 predictions, 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. For any significant declines in fair value of its equity securities, the Company reviews the severity of the security’s decline in fair value coupled with the length of time the fair value of the security has been below cost. The Company also performs a more focused review of the financial condition and near-term prospects of the issuer as well as general market conditions reflecting the prospects for the economy as a whole, and determines whether it has the intent to hold the securities until they recover in value. Assuming no credit-related factors develop, unrealized gains and losses on fixed maturities and perpetual securities are expected to diminish as investments near maturity. Based on its credit analysis, the Company believes that the issuers of its fixed maturity and perpetual security investments in the sectors shown in the table above have the ability to service their obligations to the Company. Other Investments The table below reflects the composition of the carrying value for other investments as of the periods presented. (In millions) September 30, 2017 December 31, 2016 Other investments: Commercial mortgage loans $ 1,199 $ 855 Middle market loans 798 319 Policy loans 207 184 Short-term investments 57 89 Other 97 3 Total other investments $ 2,358 $ 1,450 Loans and Loan Receivables The Company classifies its commercial mortgage loans (CMLs) and middle market loans (MMLs) as held-for-investment and includes them in the other investments 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 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. As of September 30, 2017 , and December 31, 2016 , the Company's allowance for loan losses was $8 million and $3 million , respectively. As of September 30, 2017 , and December 31, 2016 , 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 September 30, 2017 , and December 31, 2016 . The Company had no troubled debt restructurings during the nine months ended September 30, 2017 and 2016. Commercial Mortgage Loans Commercial mortgage loans include transitional real estate (TRE) loans. As of September 30, 2017 , the Company had $103 million in outstanding commitments to fund commercial mortgage loans, inclusive of loans held in unit trust structures. These commitments are contingent on the final underwriting and due diligence to be performed. Middle Market Loans Middle market loans are generally considered to be below investment grade. The carrying value for middle market loans included an unfunded amount of $133 million and $91 million , as of September 30, 2017 , and December 31, 2016, respectively, that is reflected in other liabilities on the consolidated balance sheets. As of September 30, 2017 , the Company had commitments of approximately $530 million to fund potential future loan originations related to this investment program, inclusive of loans held in unit trust structures. These commitments are contingent upon the availability of middle market loans that meet the Company's underwriting criteria. Other Other investments primarily includes investments in limited partnerships. As of September 30, 2017 , the Company had $365 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 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 entities under U.S. GAAP. 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 September 30, 2017 December 31, 2016 (In millions) Cost or Amortized Fair Cost or Amortized Fair Assets: Fixed maturities, available for sale $ 4,274 $ 5,224 $ 4,168 $ 4,982 Perpetual securities, available for sale 239 211 237 208 Equity securities 595 690 972 1,044 Other investments (1) 1,500 1,491 819 789 Other assets (2) 148 148 127 127 Total assets of consolidated VIEs $ 6,756 $ 7,764 $ 6,323 $ 7,150 Liabilities: Other liabilities (2) $ 132 $ 132 $ 146 $ 146 Total liabilities of consolidated VIEs $ 132 $ 132 $ 146 $ 146 (1) Consists of CMLs, MMLs, and 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, and/or credit default swaps (CDS), 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 and the underlying collateral and the reference corporate entities covered by any CDS contracts were all investment grade at the time of issuance. Investments in Unit Trust Structures The Company invests through unit trust structures in yen-denominated public equity securities, U.S. dollar-denominated public equity securities, bank loans, commercial mortgage loans, infrastructure debt, middle market loans, and alternative investments in limited partnerships. The Company is the only investor in these trusts and meets the requirements to consolidate these trusts under U.S. GAAP. The yen-denominated and U.S. dollar-denominated equity securities, bank loans and certain infrastructure debt are classified as available for sale in the financial statements. The commercial mortgage loans, middle market loans and certain infrastructure debt that meets the criteria to be classified as a loan are classified as loans held for investment and reflected in other investments on the consolidated balance sheets at amortized cost. Limited partnership investments are recognized as equity method investments. 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 September 30, 2017 December 31, 2016 (In millions) Amortized Fair Amortized Fair Assets: Fixed maturities, available for sale $ 4,766 $ 5,439 $ 4,729 $ 5,261 Perpetual securities, available for sale 177 220 172 200 Fixed maturities, held to maturity 2,645 3,047 2,563 2,948 Other investments 50 50 1 1 Total investments in VIEs not consolidated $ 7,638 $ 8,756 $ 7,465 $ 8,410 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's security lending policy requires that the fair value of the securities and/or unrestricted cash received as collateral be 102% or more of the fair value of the loaned securities. These securities 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. The Company receives cash or other securities as collateral for such loans. 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. Details of the Company's securities lending activities were as follows: Securities Lending Transactions Accounted for as Secured Borrowings September 30, 2017 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Total Securities lending transactions: Public utilities $ 37 $ 0 $ 37 Banks/financial institutions 37 0 37 Other corporate 434 0 434 Equity securities 14 0 14 Total borrowings $ 522 $ 0 $ 522 Gross amount of recognized liabilities for securities lending transactions $ 522 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 0 (1) These securities are pledged as collateral under the Company's U.S. securities lending program and can be called at its discretion; therefore, they are classified as Overnight and Continuous. Securities Lending Transactions Accounted for as Secured Borrowings December 31, 2016 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Total Securities lending transactions: Public utilities $ 62 $ 0 $ 62 Banks/financial institutions 34 0 34 Other corporate 430 0 430 Total borrowings $ 526 $ 0 $ 526 Gross amount of recognized liabilities for securities lending transactions $ 526 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 0 (1) These securities are pledged as collateral under the Company's U.S. securities lending program and can be called at its 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 September 30, 2017 , and December 31, 2016 , respectively. Certain fixed-maturity securities can be pledged as collateral as part of derivative transactions, or pledged to support state deposit requirements or certain investment programs. For additional information regarding pledged securities related to derivative transactions, see Note 4.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS The Company's freestanding derivative financial instruments have historically consisted of: (1) foreign currency forwards and options used in hedging foreign exchange risk on U.S. dollar-denominated investments in Aflac Japan's portfolio; (2) 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; (3) swaps associated with the Company's notes payable, consisting of cross-currency interest rate swaps, also referred to as foreign currency swaps, associated with certain senior notes and its subordinated debentures; (4) foreign currency swaps and credit default swaps that are associated with investments in special-purpose entities, including VIEs where the Company is the primary beneficiary; and (5) options on interest rate swaps (or interest rate swaptions) and futures used to hedge interest rate risk for certain available-for-sale securities. The Company does not use derivative financial instruments for trading purposes, nor does it engage in leveraged derivative transactions. 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 an accounting hedge. The Company utilizes a net investment hedge to mitigate foreign exchange exposure resulting from its net investment in Aflac Japan. In addition to designating derivatives as hedging instruments, the Company has designated the majority of the Parent Company's yen-denominated liabilities (notes payable and loans) as nonderivative hedging instruments for this net investment hedge. 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 are 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 a fixed amount of U.S. dollar put options and sell U.S. dollar call options. The combination of these two actions 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. Foreign currency forwards and options are also used to hedge the currency risk associated with the net investment in Aflac Japan. In these forward transactions, Aflac agrees with another party to buy a fixed amount of U.S. dollars and sell a corresponding amount of yen at a specified future date. In the option transactions, the Company uses 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 results in no net premium being paid (i.e. a costless or 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 currencies at a future date at an agreed upon exchange rate. 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. The only CDS that the Company currently holds relates to components of an investment in a VIE and is used to assume credit risk related to an individual security. This CDS contract entitles the consolidated VIE to receive periodic fees in exchange for an obligation to compensate the derivative counterparties should the referenced security issuer experience a credit event, as defined in the contract. Interest rate swaps involve the periodic exchange of cash flows with other parties, at specified intervals, calculated using agreed upon rates or other financial variables and notional principal amounts. Typically, at the time a swap is entered into, the cash flow streams exchanged by the counterparties are equal in value. No cash or principal payments are exchanged at the inception of the contract. Interest rate swaps are primarily used to convert interest receipts on floating-rate fixed-maturity securities contracts to fixed rates. These derivatives are predominantly used to better match cash receipts from assets with cash disbursements required to fund liabilities. Interest rate swaptions are options on interest rate swaps. Interest rate collars are combinations of two swaption positions and are executed in order to hedge certain U.S. dollar-denominated available-for-sale securities that are held in the Aflac Japan segment. The Company uses collars to protect against significant changes in the fair value associated with its U.S. dollar-denominated available-for-sale securities due to interest rates. In order to maximize the efficiency of the collars while minimizing cost, the Company sets the strike price on each collar so that the premium paid for the ‘payer leg’ is offset by the premium received for having sold the ‘receiver leg.' Periodically, the Company may enter into other derivative transactions depending on general economic conditions. Derivative Balance Sheet Classification The tables below summarize 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. 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. September 30, 2017 December 31, 2016 (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 $ 75 $ 0 $ (9 ) $ 75 $ 0 $ (10 ) Total cash flow hedges 75 0 (9 ) 75 0 (10 ) Fair value hedges: Foreign currency forwards 9,278 0 (411 ) 10,965 0 (759 ) Foreign currency options 5,660 0 (20 ) 4,224 2 (32 ) Total fair value hedges 14,938 0 (431 ) 15,189 2 (791 ) Net investment hedge: Foreign currency forwards 48 1 0 209 5 (2 ) Foreign currency options 564 17 (4 ) 843 41 (17 ) Total net investment hedge 612 18 (4 ) 1,052 46 (19 ) Non-qualifying strategies: Foreign currency swaps 5,387 301 (187 ) 6,266 490 (220 ) Foreign currency forwards 7,124 159 (343 ) 21,218 667 (956 ) Foreign currency options 25 0 0 41 0 (2 ) Credit default swaps 89 1 0 86 2 0 Total non-qualifying strategies 12,625 461 (530 ) 27,611 1,159 (1,178 ) Total derivatives $ 28,250 $ 479 $ (974 ) $ 43,927 $ 1,207 $ (1,998 ) Balance Sheet Location Other assets $ 9,509 $ 479 $ 0 $ 18,329 $ 1,207 $ 0 Other liabilities 18,741 0 (974 ) 25,598 0 (1,998 ) Total derivatives $ 28,250 $ 479 $ (974 ) $ 43,927 $ 1,207 $ (1,998 ) Cash Flow Hedges Certain of the Company's consolidated VIEs have foreign currency swaps that qualify for hedge accounting treatment. For those that have qualified, the Company has designated the derivative 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 maximum length of time for which these cash flows are hedged is nine years. The remaining derivatives in the Company's consolidated VIEs that have not qualified for hedge accounting are included in “non-qualifying strategies.” Fair Value Hedges The Company designates and accounts for certain foreign currency forwards and options as fair value hedges when they meet the requirements for hedge accounting. These foreign currency forwards and options hedge the foreign currency exposure of certain U.S. dollar-denominated investments. The Company recognizes gains and losses on these derivatives and the related hedged items in current earnings within derivative and other gains (losses). 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 excluded from the assessment of hedge effectiveness. The Company designates and accounts for interest rate swaptions as fair value hedges when they meet the requirements for hedge accounting. These interest rate swaptions hedge the interest rate exposure of certain U.S. dollar-denominated fixed maturity securities within the investment portfolio of the Company's Aflac Japan segment. The Company recognizes gains and losses on these derivatives and the related hedged items in current earnings within derivative and other gains (losses). The change in the fair value of the interest rate swaptions related to the time value of the option is excluded from the assessment of hedge effectiveness. 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) Gains (Losses) Gains (Losses) Ineffectiveness Three Months Ended September 30, 2017: Foreign currency Fixed-maturity and equity securities $ (114 ) $ (53 ) $ (61 ) $ 61 $ 0 Foreign currency Fixed-maturity securities (14 ) (14 ) 0 0 0 Nine Months Ended September 30, 2017: Foreign currency forwards Fixed-maturity and equity securities $ 193 $ (151 ) $ 344 $ (326 ) $ 18 Foreign currency options Fixed-maturity securities 3 (8 ) 11 (10 ) 1 Three Months Ended September 30, 2016: Foreign currency Fixed-maturity and equity securities $ 90 $ (186 ) $ 276 $ (288 ) $ (12 ) Foreign currency options Fixed-maturity securities (4 ) (4 ) 0 0 0 Nine Months Ended September 30, 2016: Foreign currency forwards Fixed-maturity and equity securities $ 2,103 $ (278 ) $ 2,381 $ (2,406 ) $ (25 ) Foreign currency options Fixed-maturity securities 2 2 0 0 0 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 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 used foreign exchange forwards and options to hedge foreign exchange risk on 21.9 billion yen and 45.0 billion yen of profit repatriation received from Aflac Japan in September 2017 and July 2017, respectively. As of September 30, 2017 , the Company had foreign exchange forwards and options as part of a hedge on 68.9 billion yen of future profit repatriation. The Company's net investment hedge was effective during the three- and nine -month periods ended September 30, 2017 and 2016 , 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 derivative and other 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 or perpetual securities associated with these swaps is recorded through other comprehensive income. The Parent Company has cross-currency interest rate swap agreements related to its $550 million senior notes due March 2020, $350 million senior notes due February 2022, $700 million senior notes due June 2023, $750 million senior notes due November 2024, $450 million senior notes due March 2025, and $500 million subordinated debentures due September 2052. Changes in the values of these swaps are recorded through current period earnings. For additional information regarding these swaps, see Note 8 in this report and Note 9 of the Notes to the Consolidated Financial Statements in the 2016 Annual Report. In 2016, the Company began using foreign exchange forwards to mitigate the currency risk of its U.S. dollar-denominated loan receivables held within the Aflac Japan segment. As of September 30, 2017 , the outstanding derivative notional amounts associated with these U.S. dollar-denominated loan receivables were approximately $1.6 billion . The Company has not elected to apply hedge accounting for these loan receivables due to the change in fair value of the foreign exchange forwards and the foreign currency remeasurement of the loan receivables being recorded through current period earnings, and generally offsetting each other within realized investment gains (losses). 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 September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (In millions) Realized Investment Other (1) Realized Investment Other (1) Realized Investment Other (1) Realized Investment Other (1) Qualifying hedges: Cash flow hedges: Foreign currency swaps $ 0 $ (1 ) $ 0 $ 0 $ 0 $ 0 $ 1 $ 11 Total cash flow hedges 0 (1 ) 0 0 0 0 1 11 Fair value hedges: Foreign currency forwards (2) (53 ) 0 (198 ) 0 (133 ) 0 (303 ) 0 Foreign currency options (2) (14 ) 0 (4 ) 0 (7 ) 0 2 0 Total fair value hedges (67 ) 0 (202 ) 0 (140 ) 0 (301 ) 0 Net investment hedge: Non- derivative hedging instruments 0 5 0 (2 ) 0 (13 ) 0 (39 ) Foreign currency forwards 0 4 0 (28 ) 0 (24 ) 0 (161 ) Foreign currency options 0 (5 ) 0 31 0 3 0 0 Total net investment hedge 0 4 0 1 0 (34 ) 0 (200 ) Non-qualifying strategies: Foreign currency swaps 17 0 (51 ) 0 43 0 (145 ) 0 Foreign currency forwards 10 0 144 0 (46 ) 0 165 0 Credit default swaps 0 0 2 0 0 0 2 0 Total non- qualifying strategies 27 0 95 0 (3 ) 0 22 0 Total $ (40 ) $ 3 $ (107 ) $ 1 $ (143 ) $ (34 ) $ (278 ) $ (189 ) (1) Cash flow hedge items 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). (2) Impact shown net of effect of hedged items (see Fair Value Hedges section of this Note 4 for further detail) The Company reclassified an immaterial amount related to its cash flow hedges from accumulated other comprehensive income (loss) into earnings for the three- and nine -month periods ended September 30, 2017 , and reclassified an immaterial amount and a $1 million gain for the three- and nine -month periods ended September 30, 2016 , respectively. There was no gain or loss reclassified from accumulated other comprehensive income (loss) into earnings related to the net investment hedge for the three- and nine -month periods ended September 30, 2017 and 2016 , respectively. As of September 30, 2017 , 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; foreign currency options; and interest rate swaptions, 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, foreign currency options and interest rate swaptions is mitigated by collateral posting requirements that counterparties to those transactions must meet. As of September 30, 2017 , there were 15 counterparties to the Company's derivative agreements, with five comprising 67% of the aggregate notional amount. The counterparties to these derivatives are financial institutions with the following credit ratings: September 30, 2017 December 31, 2016 (In millions) Notional Amount Asset Derivatives Liability Derivatives Notional Amount Asset Derivatives Liability Derivatives Counterparties' credit rating: AA $ 5,553 $ 90 $ (189 ) $ 6,844 $ 247 $ (308 ) A 22,257 381 (718 ) 36,019 900 (1,621 ) BBB 440 8 (67 ) 1,064 60 (69 ) Total $ 28,250 $ 479 $ (974 ) $ 43,927 $ 1,207 $ (1,998 ) The Company engages in 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. 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 $623 million and $1.2 billion as of September 30, 2017 , and December 31, 2016 , respectively. If the credit-risk-related contingent features underlying these agreements had been triggered on September 30, 2017 , the Company estimates that it would be required to post a maximum of $5 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 Aflac and its 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 September 30, 2017 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 $ 331 $ 0 $ 331 $ (219 ) $ 0 $ (112 ) $ 0 Derivative assets not subject to a master netting agreement or offsetting arrangement 148 148 148 Total derivative assets 479 0 479 (219 ) 0 (112 ) 148 Securities lending and similar arrangements 509 0 509 0 0 (509 ) 0 Total $ 988 $ 0 $ 988 $ (219 ) $ 0 $ (621 ) $ 148 December 31, 2016 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 $ 1,080 $ 0 $ 1,080 $ (698 ) $ 0 $ (382 ) $ 0 Derivative assets not subject to a master netting agreement or offsetting arrangement 127 127 127 Total derivative assets 1,207 0 1,207 (698 ) 0 (382 ) 127 Securities lending and similar arrangements 513 0 513 0 0 (513 ) 0 Total $ 1,720 $ 0 $ 1,720 $ (698 ) $ 0 $ (895 ) $ 127 Offsetting of Financial Liabilities and Derivative Liabilities September 30, 2017 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 $ (842 ) $ 0 $ (842 ) $ 219 $ 611 $ 7 $ (5 ) Derivative liabilities not subject to a master netting agreement or offsetting arrangement (132 ) (132 ) (132 ) Total derivative liabilities (974 ) 0 (974 ) 219 611 7 (137 ) Securities lending and similar arrangements (522 ) 0 (522 ) 509 0 0 (13 ) Total $ (1,496 ) $ 0 $ (1,496 ) $ 728 $ 611 $ 7 $ (150 ) December 31, 2016 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 $ (1,852 ) $ 0 $ (1,852 ) $ 698 $ 1,130 $ 21 $ (3 ) Derivative liabilities not subject to a master netting agreement or offsetting arrangement (146 ) (146 ) (146 ) Total derivative liabilities (1,998 ) 0 (1,998 ) 698 1,130 21 (149 ) Securities lending and similar arrangements (526 ) 0 (526 ) 513 0 0 (13 ) Total $ (2,524 ) $ 0 $ (2,524 ) $ 1,211 $ 1,130 $ 21 $ (162 ) 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 2016 Annual Report.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2017
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. September 30, 2017 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturities: Government and agencies $ 29,067 $ 971 $ 0 $ 30,038 Municipalities 0 1,292 0 1,292 Mortgage- and asset-backed securities 0 278 178 456 Public utilities 0 7,938 77 8,015 Sovereign and supranational 0 2,029 0 2,029 Banks/financial institutions 0 6,985 25 7,010 Other corporate 0 31,473 102 31,575 Total fixed maturities 29,067 50,966 382 80,415 Perpetual securities: Banks/financial institutions 0 1,627 0 1,627 Other corporate 0 236 0 236 Total perpetual securities 0 1,863 0 1,863 Equity securities 905 5 18 928 Other assets: Foreign currency swaps 0 154 147 301 Foreign currency forwards 0 160 0 160 Foreign currency options 0 17 0 17 Credit default swaps 0 0 1 1 Total other assets 0 331 148 479 Other investments 57 0 0 57 Cash and cash equivalents 4,927 0 0 4,927 Total assets $ 34,956 $ 53,165 $ 548 $ 88,669 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 64 $ 132 $ 196 Foreign currency forwards 0 754 0 754 Foreign currency options 0 24 0 24 Total liabilities $ 0 $ 842 $ 132 $ 974 December 31, 2016 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturities: Government and agencies $ 25,387 $ 827 $ 0 $ 26,214 Municipalities 0 1,295 0 1,295 Mortgage- and asset-backed securities 0 1,139 198 1,337 Public utilities 0 7,667 16 7,683 Sovereign and supranational 0 1,469 0 1,469 Banks/financial institutions 0 6,038 25 6,063 Other corporate 0 29,699 0 29,699 Total fixed maturities 25,387 48,134 239 73,760 Perpetual securities: Banks/financial institutions 0 1,420 0 1,420 Other corporate 0 213 0 213 Total perpetual securities 0 1,633 0 1,633 Equity securities 1,300 6 3 1,309 Other assets: Foreign currency swaps 0 365 125 490 Foreign currency forwards 0 672 0 672 Foreign currency options 0 43 0 43 Credit default swaps 0 0 2 2 Total other assets 0 1,080 127 1,207 Other investments 276 0 0 276 Cash and cash equivalents 4,859 0 0 4,859 Total assets $ 31,822 $ 50,853 $ 369 $ 83,044 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 84 $ 146 $ 230 Foreign currency forwards 0 1,717 0 1,717 Foreign currency options 0 51 0 51 Total liabilities $ 0 $ 1,852 $ 146 $ 1,998 U.S. GAAP requires disclosure of the fair value of certain financial instruments including those that are not carried at fair value. The carrying amounts for cash and cash equivalents, other investments (excluding loan receivables), receivables, accrued investment income, accounts payable, cash collateral and payables for security transactions approximated their fair values due to the nature of these instruments. Liabilities for future policy benefits and unpaid policy claims are not financial instruments as defined by U.S. GAAP. 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. September 30, 2017 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturities: Government and agencies $ 21,385 $ 26,455 $ 0 $ 0 $ 26,455 Municipalities 359 0 463 0 463 Mortgage and asset-backed 27 0 9 20 29 Public utilities 3,308 0 3,734 0 3,734 Sovereign and 1,527 0 1,846 0 1,846 Banks/financial institutions 2,700 0 2,887 0 2,887 Other corporate 2,692 0 3,185 0 3,185 Other investments (1) 2,011 0 15 1,985 2,000 Total assets $ 34,009 $ 26,455 $ 12,139 $ 2,005 $ 40,599 Liabilities: Other policyholders’ funds $ 6,967 $ 0 $ 0 $ 6,849 $ 6,849 Notes payable 5,230 506 4,780 265 5,551 Total liabilities $ 12,197 $ 506 $ 4,780 $ 7,114 $ 12,400 (1) Excludes policy loans of $207 and equity method investments of $83 , at carrying value December 31, 2016 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturities: Government and agencies $ 20,702 $ 26,040 $ 0 $ 0 $ 26,040 Municipalities 350 0 457 0 457 Mortgage and asset-backed 30 0 10 22 32 Public utilities 3,201 0 3,536 0 3,536 Sovereign and 2,602 0 2,877 0 2,877 Banks/financial institutions 3,731 0 3,900 0 3,900 Other corporate 2,734 0 3,179 0 3,179 Other investments 1,174 0 0 1,142 1,142 Total assets $ 34,524 $ 26,040 $ 13,959 $ 1,164 $ 41,163 Liabilities: Other policyholders’ funds $ 6,659 $ 0 $ 0 $ 6,540 $ 6,540 Notes payable 5,339 0 0 5,530 5,530 Total liabilities $ 11,998 $ 0 $ 0 $ 12,070 $ 12,070 Fair Value of Financial Instruments Fixed maturities, perpetual securities, and equity securities The Company determines the fair values of its fixed maturity securities, perpetual 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. The output of this analysis is presented to the Company's Valuation and Classification Subcommittee (VCS). Based on the analysis provided to the VCS, 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 maturities 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 maturities, perpetual securities, and equity securities. September 30, 2017 (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 maturities: Government and agencies: Third party pricing vendor $ 29,067 $ 971 $ 0 $ 30,038 Total government and agencies 29,067 971 0 30,038 Municipalities: Third party pricing vendor 0 1,292 0 1,292 Total municipalities 0 1,292 0 1,292 Mortgage- and asset-backed securities: Third party pricing vendor 0 278 0 278 Broker/other 0 0 178 178 Total mortgage- and asset-backed securities 0 278 178 456 Public utilities: Third party pricing vendor 0 7,938 0 7,938 Broker/other 0 0 77 77 Total public utilities 0 7,938 77 8,015 Sovereign and supranational: Third party pricing vendor 0 2,029 0 2,029 Total sovereign and supranational 0 2,029 0 2,029 Banks/financial institutions: Third party pricing vendor 0 6,985 0 6,985 Broker/other 0 0 25 25 Total banks/financial institutions 0 6,985 25 7,010 Other corporate: Third party pricing vendor 0 31,473 0 31,473 Broker/other 0 0 102 102 Total other corporate 0 31,473 102 31,575 Total fixed maturities 29,067 50,966 382 80,415 Perpetual securities: Banks/financial institutions: Third party pricing vendor 0 1,627 0 1,627 Total banks/financial institutions 0 1,627 0 1,627 Other corporate: Third party pricing vendor 0 236 0 236 Total other corporate 0 236 0 236 Total perpetual securities 0 1,863 0 1,863 Equity securities: Third party pricing vendor 905 5 0 910 Broker/other 0 0 18 18 Total equity securities 905 5 18 928 Total securities available for sale $ 29,972 $ 52,834 $ 400 $ 83,206 September 30, 2017 (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 maturities: Government and agencies: Third party pricing vendor $ 26,455 $ 0 $ 0 $ 26,455 Total government and agencies 26,455 0 0 26,455 Municipalities: Third party pricing vendor 0 463 0 463 Total municipalities 0 463 0 463 Mortgage- and asset-backed securities: Third party pricing vendor 0 9 0 9 Broker/other 0 0 20 20 Total mortgage- and asset-backed securities 0 9 20 29 Public utilities: Third party pricing vendor 0 3,734 0 3,734 Total public utilities 0 3,734 0 3,734 Sovereign and supranational: Third party pricing vendor 0 1,846 0 1,846 Total sovereign and supranational 0 1,846 0 1,846 Banks/financial institutions: Third party pricing vendor 0 2,887 0 2,887 Total banks/financial institutions 0 2,887 0 2,887 Other corporate: Third party pricing vendor 0 3,185 0 3,185 Total other corporate 0 3,185 0 3,185 Total securities held to maturity $ 26,455 $ 12,124 $ 20 $ 38,599 December 31, 2016 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities available for sale, carried at fair value: Fixed maturities: Government and agencies: Third party pricing vendor $ 25,387 $ 827 $ 0 $ 26,214 Total government and agencies 25,387 827 0 26,214 Municipalities: Third party pricing vendor 0 1,295 0 1,295 Total municipalities 0 1,295 0 1,295 Mortgage- and asset-backed securities: Third party pricing vendor 0 1,139 0 1,139 Broker/other 0 0 198 198 Total mortgage- and asset-backed securities 0 1,139 198 1,337 Public utilities: Third party pricing vendor 0 7,667 0 7,667 Broker/other 0 0 16 16 Total public utilities 0 7,667 16 7,683 Sovereign and supranational: Third party pricing vendor 0 1,469 0 1,469 Total sovereign and supranational 0 1,469 0 1,469 Banks/financial institutions: Third party pricing vendor 0 6,038 0 6,038 Broker/other 0 0 25 25 Total banks/financial institutions 0 6,038 25 6,063 Other corporate: Third party pricing vendor 0 29,699 0 29,699 Total other corporate 0 29,699 0 29,699 Total fixed maturities 25,387 48,134 239 73,760 Perpetual securities: Banks/financial institutions: Third party pricing vendor 0 1,420 0 1,420 Total banks/financial institutions 0 1,420 0 1,420 Other corporate: Third party pricing vendor 0 213 0 213 Total other corporate 0 213 0 213 Total perpetual securities 0 1,633 0 1,633 Equity securities: Third party pricing vendor 1,300 6 0 1,306 Broker/other 0 0 3 3 Total equity securities 1,300 6 3 1,309 Total securities available for sale $ 26,687 $ 49,773 $ 242 $ 76,702 December 31, 2016 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities held to maturity, carried at amortized cost: Fixed maturities: Government and agencies: Third party pricing vendor $ 26,040 $ 0 $ 0 $ 26,040 Total government and agencies 26,040 0 0 26,040 Municipalities: Third party pricing vendor 0 457 0 457 Total municipalities 0 457 0 457 Mortgage- and asset-backed securities: Third party pricing vendor 0 10 0 10 Broker/other 0 0 22 22 Total mortgage- and asset-backed securities 0 10 22 32 Public utilities: Third party pricing vendor 0 3,536 0 3,536 Total public utilities 0 3,536 0 3,536 Sovereign and supranational: Third party pricing vendor 0 2,877 0 2,877 Total sovereign and supranational 0 2,877 0 2,877 Banks/financial institutions: Third party pricing vendor 0 3,900 0 3,900 Total banks/financial institutions 0 3,900 0 3,900 Other corporate: Third party pricing vendor 0 3,179 0 3,179 Total other corporate 0 3,179 0 3,179 Total securities held to maturity $ 26,040 $ 13,959 $ 22 $ 40,021 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. 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 fair values of the foreign currency forwards, options, and interest rate swaptions 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 and subordinated debentures 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. 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. Other investments Other investments where fair value is disclosed above include short-term investments and loan receivables. Loan receivables include 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 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 As of December 31, 2016, the fair values of the Company's publicly issued notes payable were obtained from a limited number of independent brokers and classified as Level 3 within the fair value hierarchy. However, in 2017 recognizing the similarities of the Company's publicly issued notes payable to fixed income securities in its investment portfolios, the Company aligned the determination of the fair values of these liabilities with its practices of determining asset fair values whereby the Company utilizes available sources of observable inputs from third party pricing vendors; therefore, the fair values of the Company's publicly issued notes payable were reclassified into Level 2 from Level 3 in the first quarter of 2017. Further review of available sources for these liabilities has led to reclassifying the Parent Company’s subordinated debentures into Level 1 from Level 2 in the second quarter of 2017 given these securities are listed and traded on an exchange where their valuations reflect quoted market prices for identical assets or liabilities in an active market . The fair values of the Company's yen-denominated loans approximate their carrying values. Transfers between Hierarchy Levels and Level 3 Rollforward During the three- and nine -month periods ended September 30, 2017 and 2016 , 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 available-for-sale investments and derivatives classified as Level 3. Three Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 188 $ 53 $ 25 $ 77 $ 14 $ 7 $ 2 $ 366 Realized investment gains (losses) included in earnings 0 0 0 0 0 8 (1 ) 7 Unrealized gains (losses) included in other comprehensive income (loss) (2 ) 0 0 1 0 0 0 (1 ) Purchases, issuances, sales and settlements: Purchases 0 24 0 25 4 0 0 53 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 (1 ) 0 0 0 (1 ) Settlements (8 ) 0 0 0 0 0 0 (8 ) 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 $ 178 $ 77 $ 25 $ 102 $ 18 $ 15 $ 1 $ 416 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ 8 $ (1 ) $ 7 (1) Derivative assets and liabilities are presented net Three Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 252 $ 0 $ 26 $ 0 $ 3 $ 59 $ 1 $ 341 Realized investment gains (losses) included in 0 0 0 0 0 (18 ) 2 (16 ) Unrealized gains (losses) included in other 1 0 0 0 0 0 0 1 Purchases, issuances, sales and settlements: Purchases 0 0 0 0 0 0 0 0 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 0 0 0 0 0 Settlements (13 ) 0 0 0 0 0 0 (13 ) 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 $ 240 $ 0 $ 26 $ 0 $ 3 $ 41 $ 3 $ 313 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ (18 ) $ 2 $ (16 ) (1) Derivative assets and liabilities are presented net Nine Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 198 $ 16 $ 25 $ 0 $ 3 $ (21 ) $ 2 $ 223 Realized investment gains (losses) included 0 0 0 0 0 36 (1 ) 35 Unrealized gains (losses) included in other 4 0 0 3 0 0 0 7 Purchases, issuances, sales and settlements: Purchases 0 61 0 100 16 0 0 177 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 (1 ) (1 ) 0 0 (2 ) Settlements (24 ) 0 0 0 0 0 0 (24 ) 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 $ 178 $ 77 $ 25 $ 102 $ 18 $ 15 $ 1 $ 416 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ 36 $ (1 ) $ 35 (1) Derivative assets and liabilities are presented net Nine Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 220 $ 0 $ 26 $ 0 $ 3 $ (192 ) $ 1 $ 58 Realized investment gains (losses) included in earnings 0 0 0 0 0 250 2 252 Unrealized gains (losses) included in other comprehensive income (loss) 48 0 0 0 0 (16 ) 0 32 Purchases, issuances, sales and settlements: Purchases 0 0 0 0 0 0 0 0 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 0 0 0 0 0 Settlements (28 ) 0 0 0 0 (1 ) 0 (29 ) 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 $ 240 $ 0 $ 26 $ 0 $ 3 $ 41 $ 3 $ 313 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ 250 $ 2 $ 252 (1) Derivative assets and liabilities are presented net Fair Value Sensitivity Level 3 Significant Unobservable Input Sensitivity The following tables summarize the significant unobservable inputs used in the valuation of the Company's Level 3 available-for-sale investments and derivatives. Included in the tables are the inputs or range of possible inputs that have an effect on the overall valuation of the financial instruments. September 30, 2017 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturities: Mortgage- and asset-backed securities $ 178 Consensus pricing Offered quotes N/A (d) Public utilities 77 Discounted cash flow Historical volatility N/A (d) Banks/financial institutions 25 Consensus pricing Offered quotes N/A (d) Other corporate 102 Discounted cash flow Historical volatility N/A (e) Equity securities 18 Net asset value Offered quotes $1 - $724 ($6) Other assets: Foreign currency swaps 27 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 11 - 116 bps Foreign exchange rates 21.00% (c) 45 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 11 - 83 bps 75 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) Foreign exchange rates 21.00% (c) Credit default swaps 1 Discounted cash flow Base correlation 62.73% - 66.88% (e) CDS spreads 19 bps Recovery rate 37.24% Total assets $ 548 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate (d) 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. (e) Range of base correlation for the Company's bespoke tranche for attachment and detachment points corresponding to market indices. September 30, 2017 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Liabilities: Other liabilities: Foreign currency swaps $ 112 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 11 - 116 bps Foreign exchange rates 21.00% (c) 11 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 9 - 120 bps 9 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) Foreign exchange rates 21.00% (c) Total liabilities $ 132 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate December 31, 2016 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturities: Mortgage- and asset-backed securities $ 198 Consensus pricing Offered quotes N/A (d) Public utilities 16 Discounted cash flow Historical volatility N/A (d) Banks/financial institutions 25 Consensus pricing Offered quotes N/A (d) Equity securities 3 Net asset value Offered quotes $1-$701 ($8) Other assets: Foreign currency swaps 16 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 17 - 172 bps Foreign exchange rates 21.47% (c) 29 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 16 - 88 bps 80 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) Foreign exchange rates 21.47% (c) Credit default swaps 2 Discounted cash flow Base correlation 52.18% - 56.07% (e) CDS spreads 54 bps Recovery rate 36.69% Total assets $ 369 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate (d) 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. (e) Range of base correlation for the Company's bespoke tranche for attachment and detachment points corresponding to market indices December 31, 2016 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Liabilities: Other liabilities: Foreign currency swaps $ 113 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 17 - 172 bps Foreign exchange rates 21.47% (c) 23 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 24 - 216 bps 10 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) Foreign exchange rates 21.47% (c) Total liabilities $ 146 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate The following is a discussion of the significant unobservable inputs or valuation techniques used in determining the fair value of securities and derivatives classified as Level 3. 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, CDS Spreads, Foreign Exchange Rates The significant drivers of the valuation of the interest and foreign exchange swaps are interest rates, foreign exchange rates and CDS spreads. The Company's swaps have long maturities that increase the sensitivity of the swaps to interest rate fluctuations. Since most of the Company's yen-denominated cross currency swaps are in a net liability position, an increase in interest rates will decrease the liabilities and increase the value of the swap. Foreign exchange swaps also have a lump-sum final settlement of foreign exchange principal receivables at the termination of the swap. An increase in yen interest rates will decrease the value of the final settlement foreign exchange receivables and decrease the value of the swap, and an increase in U.S. dollar interest rates will increase the swap value. A similar sensitivity pattern is observed for the foreign exchange rates. When the spot U.S. dollar/Japanese yen (USD/JPY) foreign exchange rate decreases and the swap is receiving a final exchange payment in JPY, the swap value will increase due to the appreciation of the JPY. Most of the Company's swaps are designed to receive payments in JPY at the termination and will thus be impacted by the USD/JPY foreign exchange rate in this way. In cases where there is no final foreign exchange receivable in JPY and the Company is paying JPY as interest payments and receiving USD, a decrease in the foreign exchange rate will lead to a decrease in the swap value. 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. Base Correlations, CDS Spreads, Recovery Rates The Company's remaining collateralized debt obligation (CDO) is a tranche on a basket of single-name credit default swaps. The risk in this synthetic CDO comes from the single-name CDS risk and the correlations between the single names. The valuation of synthetic CDOs is dependent on the calibration of market prices for interest rates, single name CDS default probabilities

POLICY LIABILITIES

POLICY LIABILITIES	9 Months Ended
	Sep. 30, 2017
Insurance Loss Reserves [Abstract]
POLICY LIABILITIES	POLICY LIABILITIES Changes in the liability for unpaid policy claims were as follows: Three Months Ended Nine Months Ended (In millions) 2017 2016 2017 2016 Unpaid supplemental health claims, beginning of period $ 3,872 $ 3,941 $ 3,707 $ 3,548 Less reinsurance recoverables 30 30 27 26 Net balance, beginning of period 3,842 3,911 3,680 3,522 Add claims incurred during the period related to: Current year 1,759 1,843 5,278 5,309 Prior years (126 ) (148 ) (386 ) (374 ) Total incurred 1,633 1,695 4,892 4,935 Less claims paid during the period on claims incurred during: Current year 1,357 1,462 3,074 3,160 Prior years 234 232 1,697 1,722 Total paid 1,591 1,694 4,771 4,882 Effect of foreign exchange rate changes on unpaid claims (14 ) 42 69 379 Net balance, end of period 3,870 3,954 3,870 3,954 Add reinsurance recoverables 30 31 30 31 Unpaid supplemental health claims, end of period 3,900 3,985 3,900 3,985 Unpaid life claims, end of period 468 361 468 361 Total liability for unpaid policy claims $ 4,368 $ 4,346 $ 4,368 $ 4,346 The incurred claims development related to prior years reflects favorable claims experience, compared with previous estimates, primarily in the Company's lines of business in Japan. The favorable claims development of $386 million for the nine -month period ended September 30, 2017 comprises approximately $301 million from Japan, which represents approximately 78% of the total. Excluding the impact of foreign exchange of a loss of approximately $13 million from December 31, 2016 to September 30, 2017 , the favorable claims development in Japan would have been approximately $315 million , representing approximately 82% of the total. The Company has experienced continued favorable claim trends in 2017 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.

REINSURANCE

REINSURANCE	9 Months Ended
	Sep. 30, 2017
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 $942 million , as of September 30, 2017 , 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 $906 million and $860 million as of September 30, 2017 , and December 31, 2016 , respectively. The increase in the reinsurance recoverable balance was driven by two aggregating factors: yen strengthening and the growth in reserves related to the business that has been reinsured as the policies age. The spot yen/dollar exchange rate strengthened by approximately 3% and ceded reserves increased approximately 2% from December 31, 2016 , to September 30, 2017 . The following table reconciles direct premium income and direct benefits and claims to net amounts after the effect of reinsurance. Three Months Ended Nine Months Ended (In millions) 2017 2016 2017 2016 Direct premium income $ 4,734 $ 5,119 $ 14,210 $ 14,724 Ceded to other companies: Ceded Aflac Japan closed blocks (130 ) (148 ) (390 ) (423 ) Other (12 ) (13 ) (37 ) (37 ) Assumed from other companies: Retrocession activities 54 62 163 177 Other 2 2 5 6 Net premium income $ 4,648 $ 5,022 $ 13,951 $ 14,447 Direct benefits and claims $ 3,157 $ 3,463 $ 9,403 $ 9,898 Ceded benefits and change in reserves for future benefits: Ceded Aflac Japan closed blocks (118 ) (135 ) (359 ) (385 ) Eliminations 13 16 39 44 Other (9 ) (10 ) (31 ) (26 ) Assumed from other companies: Retrocession activities 53 59 159 168 Eliminations (13 ) (16 ) (39 ) (44 ) Other 0 1 2 2 Benefits and claims, net $ 3,083 $ 3,378 $ 9,174 $ 9,657 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. This reinsurance facility agreement was renewed in 2016 and is effective until December 31, 2017. There are also additional commitment periods of a one-year duration each 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 September 30, 2017 , the Company has not executed a reinsurance treaty under this committed reinsurance facility.

NOTES PAYABLE

NOTES PAYABLE	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
NOTES PAYABLE	NOTES PAYABLE A summary of notes payable follows: (In millions) September 30, 2017 December 31, 2016 2.65% senior notes paid February 2017 $ 0 $ 649 2.40% senior notes due March 2020 545 547 4.00% senior notes due February 2022 346 348 3.625% senior notes due June 2023 694 696 3.625% senior notes due November 2024 743 745 3.25% senior notes due March 2025 445 445 2.875% senior notes due October 2026 298 298 6.90% senior notes due December 2039 221 220 6.45% senior notes due August 2040 256 254 4.00% senior notes due October 2046 394 394 5.50% subordinated debentures due September 2052 494 486 Yen-denominated senior notes: .932% senior notes due January 2027 (principal amount 60.0 billion yen) 529 0 Yen-denominated loans: Variable interest rate loan due September 2021 (.31% in 2017 and 2016, principal amount 5.0 billion yen) 44 43 Variable interest rate loan due September 2023 (.46% in 2017 and 2016, principal amount 25.0 billion yen) 221 214 Capitalized lease obligations payable through 2024 18 21 Total notes payable $ 5,248 $ 5,360 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. In January 2017, the Parent Company issued 60.0 billion yen of senior notes through a U.S. public debt offering. The notes bear interest at a fixed rate of .932% per annum, payable semi-annually, and have a 10 -year maturity. These notes may only be redeemed before maturity, in whole but not in part, upon the occurrence of certain changes affecting U.S. taxation, as specified in the indenture governing the terms of the issuance. In February 2017, the Parent Company extinguished $650 million of 2.65% senior notes upon their maturity. The Parent Company and Aflac have a 364 -day uncommitted bilateral line of credit with a third party that provides for borrowings in the amount of $100 million . Borrowings will bear interest at the rate quoted by the bank and agreed upon at the time of making such loan and will have up to a three-month maturity period. There are no related facility fees, upfront expenses or financial covenant requirements. Borrowings under this credit agreement may be used for general corporate purposes. Borrowings under the financing agreement will mature no later than three months after the last drawdown date of October 14, 2017. As of September 30, 2017 , the Company did not have any borrowings outstanding under its $100 million credit agreement. The Parent Company has a three -year senior unsecured revolving credit facility agreement with a syndicate of financial institutions that provides for borrowings of up to 100.0 billion yen on a revolving basis. Borrowings bear interest at a rate per annum equal to the Tokyo interbank market rate (TIBOR) plus, at the Company's option, either (a) the applicable TIBOR margin during the period from the closing date to the commitment termination date or (b) the applicable TIBOR margin during the term out period. The applicable margin ranges between .35% and .75% during the period from the closing date to the commitment termination date and .70% and 1.50% during the term out period, depending on the Parent Company’s debt ratings as of the date of determination. In addition, the Parent Company is required to pay a facility fee on the commitments ranging between .30% and .50% , also based on the Parent Company’s debt ratings as of the date of determination. Borrowings under this credit agreement may be used for general corporate purposes, including a capital contingency plan for the operations of the Parent Company, and will expire on the earlier of (a) March 31, 2019, or (b) the date the commitments are terminated pursuant to an event of default, as such term is defined in the credit agreement. The credit facility requires compliance with certain financial covenants on a quarterly basis. As of September 30, 2017 , the Parent Company did not have any borrowings outstanding under its 100.0 billion yen revolving credit agreement. The Parent Company and Aflac have a five -year senior unsecured revolving credit facility agreement with a syndicate of financial institutions that provides for borrowings of up to 55.0 billion yen or the equivalent of yen in U.S. dollars on a revolving basis. This credit agreement provides for borrowings in Japanese yen or the equivalent of Japanese yen in U.S. dollars on a revolving basis. Borrowings bear interest at a rate per annum equal to, at the Company's option, either (a) a eurocurrency rate determined by reference to the LIBOR for the interest period relevant to such borrowing adjusted for certain additional costs or (b) a base rate determined by reference to the highest of (1) the federal funds effective rate plus ½ of 1%, (2) the rate of interest for such day announced by Mizuho Bank, Ltd. as its prime rate and (3) the eurocurrency rate for an interest period of one month plus 1.00%, in each case plus an applicable margin. The applicable margin ranges between .79% and 1.275% for eurocurrency rate borrowings and 0.0% and .275% for base rate borrowings, depending on the Parent Company’s debt ratings as of the date of determination. In addition, the Parent Company and Aflac are required to pay a facility fee on the commitments ranging between .085% and .225% , also based on the Parent Company’s debt ratings as of the date of determination. Borrowings under the amended and restated credit facility may be used for general corporate purposes, including a capital contingency plan for the operations of the Parent Company and Aflac. The amended and restated credit facility requires compliance with certain financial covenants on a quarterly basis and will expire on the earlier of (a) September 18, 2020, or (b) the date the commitments are terminated pursuant to an event of default, as such term is defined in the credit agreement. As of September 30, 2017 , the Company did not have any borrowings outstanding under its 55.0 billion yen revolving credit agreement. The Parent Company and Aflac have an uncommitted bilateral line of credit with a third party that provides for borrowings in the amount of $50 million . Borrowings will bear interest at the rate quoted by the bank and agreed upon at the time of making such loan and will have up to a three-month maturity period. There are no related facility fees, upfront expenses or financial covenant requirements. Borrowings under this credit agreement may be used for general corporate purposes. As of September 30, 2017 , the Company did not have any borrowings outstanding under its $50 million credit agreement. The Company was in compliance with all of the covenants of its notes payable and lines of credit at September 30, 2017 . No events of default or defaults occurred during the nine -month period ended September 30, 2017 . For additional information, see Notes 4 and 9 of the Notes to the Consolidated Financial Statements in the 2016 Annual Report.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2017
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 nine -month periods ended September 30 . (In thousands of shares) 2017 2016 Common stock - issued: Balance, beginning of period 671,249 669,723 Exercise of stock options and issuance of restricted shares 1,420 1,261 Balance, end of period 672,669 670,984 Treasury stock: Balance, beginning of period 265,439 245,343 Purchases of treasury stock: Open market 13,898 18,774 Other 435 329 Dispositions of treasury stock: Shares issued to AFL Stock Plan (696 ) (822 ) Exercise of stock options (263 ) (554 ) Other (19 ) (107 ) Balance, end of period 278,794 262,963 Shares outstanding, end of period 393,875 408,021 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 Nine Months Ended (In thousands) 2017 2016 2017 2016 Anti-dilutive share-based awards 266 109 335 1,162 Share Repurchase Program During the first nine months of 2017 , the Company repurchased 13.9 million shares of its common stock in the open market for $1.0 billion as part of its share repurchase program. During the first nine months of 2016 , the Company repurchased 18.8 million shares of its common stock in the open market for $1.2 billion as part of its share repurchase program. In August 2017, the Company's board of directors authorized the purchase of an additional 40 million shares of its common stock. As of September 30, 2017 , a remaining balance of 52.9 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 Liability Adjustment Total Balance, beginning of period $ (1,580 ) $ 5,173 $ (23 ) $ (169 ) $ 3,401 Other comprehensive (135 ) 296 0 (2 ) 159 Amounts reclassified from 0 (32 ) 0 3 (29 ) Net current-period other (135 ) 264 0 1 130 Balance, end of period $ (1,715 ) $ 5,437 $ (23 ) $ (168 ) $ 3,531 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 $ (847 ) $ 6,441 $ (19 ) $ (143 ) $ 5,432 Other comprehensive 253 (342 ) 0 (1 ) (90 ) Amounts reclassified from 0 21 0 1 22 Net current-period other 253 (321 ) 0 0 (68 ) Balance, end of period $ (594 ) $ 6,120 $ (19 ) $ (143 ) $ 5,364 All amounts in the table above are net of tax. Nine Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Total Balance, beginning of period $ (1,983 ) $ 4,805 $ (24 ) $ (168 ) $ 2,630 Other comprehensive 268 653 1 (8 ) 914 Amounts reclassified from 0 (21 ) 0 8 (13 ) Net current-period other 268 632 1 0 901 Balance, end of period $ (1,715 ) $ 5,437 $ (23 ) $ (168 ) $ 3,531 All amounts in the table above are net of tax. Nine Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Liability Adjustment Total Balance, beginning of period $ (2,196 ) $ 2,986 $ (26 ) $ (139 ) $ 625 Other comprehensive 1,602 3,155 7 (7 ) 4,757 Amounts reclassified from 0 (21 ) 0 3 (18 ) Net current-period other 1,602 3,134 7 (4 ) 4,739 Balance, end of period $ (594 ) $ 6,120 $ (19 ) $ (143 ) $ 5,364 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 based on source 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 $ 56 Sales and redemptions (6 ) Other-than-temporary impairment 50 Total before tax (18 ) Tax (expense) or benefit (1) $ 32 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 $ 29 Net of tax (1) Based on 35% 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 $ (11 ) Sales and redemptions (22 ) Other-than-temporary impairment (33 ) Total before tax 12 Tax (expense) or benefit (1) $ (21 ) Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (4 ) Acquisition and operating expenses (2) Prior service (cost) credit 2 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (1 ) Net of tax Total reclassifications for the period $ (22 ) Net of tax (1) Based on 35% 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) Nine 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 $ 56 Sales and redemptions (23 ) Other-than-temporary impairment 33 Total before tax (12 ) Tax (expense) or benefit (1) $ 21 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (12 ) Acquisition and operating expenses (2) Prior service (cost) credit 0 Acquisition and operating expenses (2) 4 Tax (expense) or benefit (1) $ (8 ) Net of tax Total reclassifications for the period $ 13 Net of tax (1) Based on 35% 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) Nine 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 $ 102 Sales and redemptions (69 ) Other-than-temporary impairment 33 Total before tax (12 ) Tax (expense) or benefit (1) $ 21 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (12 ) Acquisition and operating expenses (2) Prior service (cost) credit 8 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (3 ) Net of tax Total reclassifications for the period $ 18 Net of tax (1) Based on 35% 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).

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION As of September 30, 2017 , 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 37.5 million shares including 19 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 September 30, 2017 , approximately 20.6 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 September 30, 2017 , 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 100% of 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 -year 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 September 30, 2017 . Stock Weighted-Average Aggregate Weighted-Average Outstanding 4,181 5.4 $ 108 $ 55.61 Exercisable 2,563 3.6 79 50.73 The Company received cash from the exercise of stock options in the amount of $48 million during the first nine months of 2017, compared with $59 million in the first nine months of 2016. The tax benefit realized as a result of stock option exercises and restricted stock releases was $37 million in the first nine months of 2017, compared with $29 million in the first nine months of 2016. As of September 30, 2017 , total compensation cost not yet recognized in the Company's financial statements related to restricted stock awards was $43 million , of which $17 million ( 968 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 1.1 years. There are no other contractual terms covering restricted stock awards once vested. The following table summarizes restricted stock activity during the nine -month period ended September 30 . (In thousands of shares) Shares Weighted-Average Grant-Date Fair Value Per Share Restricted stock at December 31, 2016 1,868 $ 61.76 Granted in 2017 555 72.85 Canceled in 2017 (79 ) 64.22 Vested in 2017 (486 ) 62.22 Restricted stock at September 30, 2017 1,858 $ 64.71 In February 2017, the Company granted 253 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. On January 1, 2017, the Company adopted accounting guidance related to employee share-based payment accounting, which requires an entity to elect whether to use estimates of forfeitures, or to account for forfeitures as they occur, using modified retrospective application. The Company has made an entity-wide accounting policy election to estimate the number of awards that are expected to vest (consistent with the Company's prior policy). The election and adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. 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 2016 Annual Report.

BENEFIT PLANS

BENEFIT PLANS	9 Months Ended
	Sep. 30, 2017
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 five years ; (4) active employees who were age 55 or older and who would meet the 15 years of service requirement within the next five 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, included in acquisition and operating expenses in the consolidated statement of earnings, included the following components: Three Months Ended September 30, Pension Benefits Other Japan U.S. Postretirement Benefits (In millions) 2017 2016 2017 2016 2017 2016 Components of net periodic Service cost $ 4 $ 4 $ 6 $ 5 $ 0 $ 0 Interest cost 2 2 8 8 0 0 Expected return on plan (1 ) (1 ) (6 ) (6 ) 0 0 Amortization of net actuarial 1 0 3 4 0 0 Amortization of prior service 0 0 0 0 0 (2 ) Net periodic (benefit) cost $ 6 $ 5 $ 11 $ 11 $ 0 $ (2 ) Nine Months Ended September 30, Pension Benefits Other Japan U.S. Postretirement Benefits (In millions) 2017 2016 2017 2016 2017 2016 Components of net periodic Service cost $ 13 $ 12 $ 18 $ 17 $ 0 $ 0 Interest cost 5 5 24 24 1 1 Expected return on plan (3 ) (3 ) (17 ) (17 ) 0 0 Amortization of net actuarial 2 1 10 10 0 1 Amortization of prior service 0 0 0 0 0 (8 ) Net periodic (benefit) cost $ 17 $ 15 $ 35 $ 34 $ 1 $ (6 ) During the nine months ended September 30, 2017 , Aflac Japan contributed approximately $18 million (using the weighted-average yen/dollar exchange rate for the nine -month period ending September 30, 2017 ) to the Japanese funded defined benefit plan, and Aflac U.S. contributed $40 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 2016 Annual Report.

COMMITMENTS AND CONTINGENT LIAB

COMMITMENTS AND CONTINGENT LIABILITIES	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENT LIABILITIES	COMMITMENTS AND CONTINGENT LIABILITIES Effective for 2017, 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 September 30, 2017 , the agreement has a remaining term of five years and an aggregate remaining cost of 7.8 billion yen ( $69 million using the September 30, 2017 , 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 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 expects a majority of these assessments to be paid over the next year and a majority of the tax credits to be realized over the next five years. The Company uses the most current cost estimate provided by the National Organization of Life and Health Guaranty Associations (NOLHGA) to calculate its estimated assessments and tax credits. To the extent Medicare part D related premiums are included in the industry premiums within the latest NOLHGA annual report, the Company's assessments estimate will increase. Since this information is not available at this time, the Company cannot at this time estimate the extent of the increase, if any. Guaranty fund assessments in the second and third quarters of 2017 were immaterial.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS In October 2017, the Parent Company issued 60.0 billion yen of subordinated debentures through a public debt offering under its U.S. shelf registration statement. The debentures bear interest at an initial rate of 2.108% per annum through October 22, 2027, or earlier redemption. Thereafter, the rate of the interest of the debentures will be reset every five years at a rate of interest equal to the then-current JPY 5-year Swap Offered Rate plus 205 basis points. The debentures are payable semi-annually in arrears and have a 30 -year maturity. The debentures are redeemable (i) at any time, in whole but not in part, upon the occurrence of certain tax events or certain rating agency events, as specified in the indenture governing the terms of the debentures or (ii) in 10 years, in whole or in part, at a redemption price equal to their principal amount plus accrued and unpaid interest to, but excluding, the date of redemption.

SUMMARY OF SIGNIFICANT ACCOUN21

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2017
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), which operates in the United States (Aflac U.S.) and as a branch in Japan (Aflac Japan). 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 its branch in 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 69% and 74% of the Company's total revenues in the nine -month periods ended September 30, 2017 and 2016 , respectively. The percentage of the Company's total assets attributable to Aflac Japan was 83% at both September 30, 2017 , and December 31, 2016 . Basis of Presentation The Company prepares its financial statements in accordance with U.S. generally accepted accounting principles (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 September 30, 2017 , and December 31, 2016 , the consolidated statements of earnings and comprehensive income (loss) for the three- and nine -month periods ended September 30, 2017 and 2016 , and the consolidated statements of shareholders' equity and cash flows for the nine -month periods ended September 30, 2017 and 2016 . 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, 2016 (2016 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. Prior year foreign currency transaction gains and losses have been reclassified from Other income (loss) to Realized investment gains (losses) - Derivative and other gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on net earnings or total shareholders' equity. This change in classification was made to reflect that the major source of the Company's foreign currency transaction gains and losses is directly or indirectly a result of its investment activity.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Consolidation - Interests Held through Related Parties That Are under Common Control: In October 2016, the FASB issued amendments which clarify the consolidation guidance on how a reporting entity that is the single decision maker of a variable interest entity (VIE) should treat indirect interests in the entity held through related parties that are under common control with the reporting entity when determining whether it is the primary beneficiary of that VIE. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Compensation - Stock Compensation - Improvements to Employee Share-Based Payment Accounting: In March 2016, the FASB issued amendments which simplify several aspects for share-based payment award transactions, including income tax consequences, classification of awards as either liability or equity, and classification on the statement of cash flows. The Company adopted this guidance as of January 1, 2017. The amendment requires prospective recognition of excess tax benefits and deficiencies in the income statement, rather than in paid-in capital. As a result of applying this requirement, the Company believes that recognition of excess tax benefits will increase volatility in its statement of operations, but the adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. The amendment also requires all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) to be recognized as income tax expense or benefit in the income statement. The guidance requires modified retrospective transition for settlements on all outstanding awards (both historical and future) that did not give rise to an excess benefit to be recorded through retained earnings on a cumulative-effect basis. The adoption of these amendments in the guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Additionally, the amendment requires that the minimum statutory tax withholding for all outstanding liability awards be reclassified at the date of adoption to equity (assuming equity classification results from the guidance change), and as a cumulative-effect adjustment to equity be recorded on a modified retrospective basis. The adoption of these amendments in the guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. The guidance requires certain reclassifications of balances on the statement of cash flows to or from operating and financing activities. The reclassification guidance did not have a significant impact on the Company's statement of cash flows. The amendment allows an entity to elect whether to use estimates of forfeitures, or to account for forfeitures as they occur, using modified retrospective application. The Company made an entity-wide accounting policy election to estimate the number of awards that are expected to vest (consistent with the Company's prior policy) . The election and adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Investments - Equity Method and Joint Ventures - Simplifying the Transition to the Equity Method of Accounting: In March 2016, the FASB issued amendments which eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. Per the amendments, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendments also require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Derivatives and Hedging - Contingent Put and Call Options in Debt Instruments: In March 2016, the FASB issued amendments which clarify what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts, which is one of the criteria for bifurcating an embedded derivative. Consequently, when a call (put) option is contingently exercisable, an entity does not have to assess whether the event that triggers the ability to exercise a call (put) option is related to interest rates or credit risks. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's financial position, results of operations, or disclosures. Derivatives and Hedging - Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships: In March 2016, the FASB issued amendments which clarify that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria remain intact. The Company adopted this guidance as of January 1, 2017. The adoption of this guidance 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 Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities: In August 2017, FASB issued guidance which improves and simplifies the accounting rules around hedge accounting and will create more transparency around how economic results are presented on financial statements. Issues addressed in this new guidance include: 1) risk component hedging, 2) accounting for the hedged item in fair value hedges of interest rate risk, 3) recognition and presentation of the effects of hedging instruments, and 4) amounts excluded from the assessment of hedge effectiveness. The amendments are effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted in any interim period after issuance of the guidance. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Compensation-Stock Compensation: Scope of Modification Accounting: In May 2017, the FASB issued amendments to provide guidance clarifying when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. An entity should apply modification accounting if the fair value, vesting conditions or classification of the award (as an equity instrument or liability instrument) changes as a result of the change in terms or conditions of the award. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted and should be applied prospectively. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Receivables-Nonrefundable Fees and Other Costs: Premium Amortization on Purchased Callable Debt Securities: In March 2017, the FASB issued amendments to shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount. The amendments are effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, or disclosures. Compensation-Retirement Benefit: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost: In March 2017, the FASB issued amendments requiring that an employer report the service cost component of net periodic pension cost and net periodic postretirement benefit cost in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net periodic pension cost and net periodic postretirement benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. If a separate line item or items are used to present the other components of net benefit cost, that line item or items must be appropriately described. If a separate line item or items are not used, the line item or items used in the income statement to present the other components of net benefit cost must be disclosed. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. 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, disclosures, or statements of cash flows. Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets - Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets: In February 2017, the FASB issued amendments that clarify the scope and accounting guidance for the derecognition of a nonfinancial asset or a financial asset that meets the definition of an "in substance nonfinancial asset." The amendments define an "in substance nonfinancial asset" and provide additional accounting guidance for partial sales of nonfinancial assets. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Earlier adoption is permitted for fiscal years beginning after December 15, 2016, including interim periods therein. An entity is required to apply the amendments at the same time that it applies the FASB amendments for Revenue from Contracts with Customers. The Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, disclosures, and statements of cash flows. 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 U.S. Securities and Exchange Commission (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 Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, or disclosures. Business Combinations - Clarifying the Definition of a Business: In January 2017, the FASB issued amendments clarifying when a set of assets and activities is a business. The amendments provide a screen to exclude transactions where substantially all the fair value of the transferred set is concentrated in a single asset, or group of similar assets, from being evaluated as a business. The amendments are effective for public business entities beginning after December 15, 2017, including interim periods within those periods. The Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, or disclosures. Statement of Cash Flows - Restricted Cash: In November 2016, the FASB issued amendments requiring that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The amendments are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of this guidance to have a significant impact on its financial position, results of operations, disclosures, or statement of cash flows. Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory: In October 2016, the FASB issued amendments that require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments are effective for public business entities for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. Early adoption is permitted. The Company is evaluating the impact of adoption of this guidance on its financial position, results of operations, and disclosures. Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payment s: In August 2016, the FASB issued amendments that provide guidance on eight specific statement of cash flows classification issues. The amendments are effective for public companies for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted for any interim or annual period. The adoption of this guidance is not expected to have a significant impact on the Company's financial position, results of operations, disclosures, or statements of cash flows. 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 writedown. 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. 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 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 continues to evaluate the impact of adoption of this guidance on its financial position, results of operations, and disclosures. Leases: In February 2016, the FASB issued updated guidance for accounting for leases. Per the amendments, lessees will be 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. A right-of-use asset will be recorded which represents the lessee’s right to use, or to control the use of, a specified asset for a lease term. Under the new guidance, lessor accounting is largely unchanged. The amendments are effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company has identified certain operating leases in scope of this guidance to include office space and equipment leases (See Note 15 of the Notes to the Consolidated Financial Statements in the 2016 Annual Report for current balances of leases in scope). The leases within scope of this guidance will increase the Company's right-of-use assets and lease liabilities recorded on its statement of financial position, however the Company estimates leases within scope of the guidance to represent less than 1% of its total assets as of September 30, 2017 . The Company estimates that the adoption of this guidance will not have a significant impact on its financial position, results of operations, and disclosures. Financial Instruments - Overall - Recognition and Measurement of Financial Assets and Financial Liabilities: In January 2016, the FASB issued guidance to address certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. The main provisions require that equity investments be measured at fair value with changes recognized in net income; that changes in instrument-specific credit risk for financial liabilities that are measured under the fair value option be recognized in other comprehensive income; and that entities would make the assessment of the ability to realize a deferred tax asset (DTA) related to an available-for-sale (AFS) debt security in combination with the entity's other DTAs. The amendments are effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is not permitted, with the exception of the own credit provision if an entity has elected to measure a liability at fair value. The Company has identified certain financial instruments in scope of this guidance to include certain fixed maturity securities, perpetual securities and equity securities (See Note 3 for current balances of instruments in scope). The Company estimates that the impact of this guidance will increase volatility in its statement of operations and the Company continues to evaluate the impact of this guidance on its statement of financial position, results of operations, and disclosures. Revenue from Contracts with Customers: In May 2014, the FASB issued updated guidance that affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (e.g., insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB deferred the effective date for this standard to annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods. The Company has identified revenue in scope of this guidance to include certain revenues associated with affiliated entities in support of its operations. The Company estimates the revenue within scope of the guidance to represent less than 1% of its total revenues as of September 30, 2017 . The Company estimates that the adoption of this guidance will not have a significant impact on its financial position, results of operations, and disclosures.

BUSINESS SEGMENT INFORMATION (T

BUSINESS SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated	Three Months Ended Nine Months Ended (In millions) 2017 2016 2017 2016 Revenues: Aflac Japan: Net earned premiums $ 3,200 $ 3,596 $ 9,616 $ 10,177 Net investment income, less amortized hedge costs (1) 561 607 1,676 1,802 Other income 11 10 31 29 Total Aflac Japan 3,772 4,213 11,323 12,008 Aflac U.S.: Net earned premiums 1,393 1,365 4,172 4,093 Net investment income 181 176 539 526 Other income 1 1 3 5 Total Aflac U.S. 1,575 1,542 4,714 4,624 Other business segments 69 71 204 207 Total business segment revenues 5,416 5,826 16,241 16,839 Corporate and eliminations 19 20 59 63 Total operating revenues 5,435 5,846 16,300 16,902 Realized investment gains (losses) (1), (2), (3) 71 (130 ) (57 ) (298 ) Total revenues $ 5,506 $ 5,716 $ 16,243 $ 16,604 (1) Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from net investment income when analyzing segment operations to conform to current year reporting. (2) Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations (3) Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total revenues.
Reconciliation of Operating Profit (Loss) from Segments to Consolidated	Three Months Ended Nine Months Ended (In millions) 2017 2016 2017 2016 Pretax earnings: Aflac Japan (1) $ 748 $ 827 $ 2,308 $ 2,436 Aflac U.S. 316 323 956 946 Other business segments 5 4 9 12 Total business segment pretax operating earnings 1,069 1,154 3,273 3,394 Interest expense, noninsurance operations (30 ) (31 ) (89 ) (90 ) Corporate and eliminations (25 ) (31 ) (70 ) (91 ) Pretax operating earnings 1,014 1,092 3,114 3,213 Realized investment gains (losses) (1), (2), (3) 71 (130 ) (57 ) (298 ) Other non-operating income (loss) (3) (10 ) 1 (38 ) (1 ) Total earnings before income taxes $ 1,075 $ 963 $ 3,019 $ 2,914 Income taxes applicable to pretax operating earnings $ 338 $ 379 $ 1,031 $ 1,112 Effect of foreign currency translation on after-tax (29 ) 61 (31 ) 110 (1) Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from pretax operating earnings when analyzing segment operations to conform to current year reporting. (2) Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine -month periods ended September 30, 2017 , and 2016 , respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations (3) Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total earnings before income taxes.
Reconciliation of Assets from Segment to Consolidated	Assets were as follows: (In millions) September 30, December 31, Assets: Aflac Japan $ 113,625 $ 107,858 Aflac U.S. 20,348 19,453 Other business segments 513 270 Total business segment assets 134,486 127,581 Corporate and eliminations 1,597 2,238 Total assets $ 136,083 $ 129,819

INVESTMENTS (Tables)

INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
Available-for-sale Securities	The amortized cost for the Company's investments in debt and perpetual securities, the cost for equity securities and the fair values of these investments are shown in the following tables. September 30, 2017 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value: Fixed maturities: Yen-denominated: Japan government and agencies $ 27,027 $ 3,272 $ 423 $ 29,876 Municipalities 315 26 15 326 Mortgage- and asset-backed securities 248 29 0 277 Public utilities 1,643 369 7 2,005 Sovereign and supranational 1,428 190 3 1,615 Banks/financial institutions 3,307 494 59 3,742 Other corporate 3,811 771 25 4,557 Total yen-denominated 37,779 5,151 532 42,398 U.S. dollar-denominated: U.S. government and agencies 150 12 0 162 Municipalities 818 148 0 966 Mortgage- and asset-backed securities 166 13 0 179 Public utilities 5,231 813 34 6,010 Sovereign and supranational 325 89 0 414 Banks/financial institutions 2,683 592 7 3,268 Other corporate 25,092 2,388 462 27,018 Total U.S. dollar-denominated 34,465 4,055 503 38,017 Total fixed maturities 72,244 9,206 1,035 80,415 Perpetual securities: Yen-denominated: Banks/financial institutions 1,308 277 32 1,553 Other corporate 195 41 0 236 U.S. dollar-denominated: Banks/financial institutions 46 28 0 74 Total perpetual securities 1,549 346 32 1,863 Equity securities: Yen-denominated 555 95 2 648 U.S. dollar-denominated 256 30 6 280 Total equity securities 811 125 8 928 Total securities available for sale $ 74,604 $ 9,677 $ 1,075 $ 83,206 December 31, 2016 (In millions) Cost or Gross Gross Fair Securities available for sale, carried at fair value: Fixed maturities: Yen-denominated: Japan government and agencies $ 22,857 $ 3,359 $ 160 $ 26,056 Municipalities 246 29 8 267 Mortgage- and asset-backed securities 1,096 33 8 1,121 Public utilities 1,533 318 3 1,848 Sovereign and supranational 862 186 5 1,043 Banks/financial institutions 2,673 403 74 3,002 Other corporate 3,192 623 3 3,812 Total yen-denominated 32,459 4,951 261 37,149 U.S dollar-denominated: U.S. government and agencies 148 10 0 158 Municipalities 894 142 8 1,028 Mortgage- and asset-backed securities 196 20 0 216 Public utilities 5,205 690 60 5,835 Sovereign and supranational 335 91 0 426 Banks/financial institutions 2,570 507 16 3,061 Other corporate 24,556 2,021 690 25,887 Total U.S. dollar-denominated 33,904 3,481 774 36,611 Total fixed maturities 66,363 8,432 1,035 73,760 Perpetual securities: Yen-denominated: Banks/financial institutions 1,266 128 49 1,345 Other corporate 189 24 0 213 U.S. dollar-denominated: Banks/financial institutions 51 24 0 75 Total perpetual securities 1,506 176 49 1,633 Equity securities: Yen-denominated 624 83 2 705 U.S. dollar-denominated 579 31 6 604 Total equity securities 1,203 114 8 1,309 Total securities available for sale $ 69,072 $ 8,722 $ 1,092 $ 76,702
Held-to-maturity Securities	December 31, 2016 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturities: Yen-denominated: Japan government and agencies $ 20,702 $ 5,338 $ 0 $ 26,040 Municipalities 350 107 0 457 Mortgage- and asset-backed securities 30 2 0 32 Public utilities 3,201 358 23 3,536 Sovereign and supranational 2,602 283 8 2,877 Banks/financial institutions 3,731 195 26 3,900 Other corporate 2,734 452 7 3,179 Total yen-denominated 33,350 6,735 64 40,021 Total securities held to maturity $ 33,350 $ 6,735 $ 64 $ 40,021 September 30, 2017 (In millions) Cost or Gross Gross Fair Securities held to maturity, carried at amortized cost: Fixed maturities: Yen-denominated: Japan government and agencies $ 21,385 $ 5,070 $ 0 $ 26,455 Municipalities 359 104 0 463 Mortgage- and asset-backed securities 27 2 0 29 Public utilities 3,308 426 0 3,734 Sovereign and supranational 1,527 319 0 1,846 Banks/financial institutions 2,700 205 18 2,887 Other corporate 2,692 493 0 3,185 Total yen-denominated 31,998 6,619 18 38,599 Total securities held to maturity $ 31,998 $ 6,619 $ 18 $ 38,599
Investments Classified by Contractual Maturity Date	The contractual maturities of the Company's investments in fixed maturities at September 30, 2017 , were as follows: Aflac Japan Aflac U.S. (In millions) Amortized Fair Amortized Fair Available for sale: Due in one year or less $ 175 $ 181 $ 53 $ 54 Due after one year through five years 5,734 6,029 637 682 Due after five years through 10 years 9,078 9,668 3,253 3,529 Due after 10 years 43,860 49,502 8,443 9,698 Mortgage- and asset-backed securities 290 330 40 42 Total fixed maturities available for sale $ 59,137 $ 65,710 $ 12,426 $ 14,005 Held to maturity: Due in one year or less $ 488 $ 497 $ 0 $ 0 Due after one year through five years 923 970 0 0 Due after five years through 10 years 1,638 1,810 0 0 Due after 10 years 28,922 35,293 0 0 Mortgage- and asset-backed securities 27 29 0 0 Total fixed maturities held to maturity $ 31,998 $ 38,599 $ 0 $ 0
Economic Maturities of Investments in Perpetual Securities	The economic maturities of the Company's investments in perpetual securities, which were all reported as available for sale at September 30, 2017 , were as follows: Aflac Japan Aflac U.S. (In millions) Amortized Fair Amortized Fair Due in one year or less $ 84 $ 85 $ 0 $ 0 Due after one year through five years 194 236 0 0 Due after 10 years 1,232 1,482 39 60 Total perpetual securities available for sale $ 1,510 $ 1,803 $ 39 $ 60
Investment Exposures Exceeding Ten Percent Shareholders Equity	Investment exposures that individually exceeded 10% of shareholders' equity were as follows: September 30, 2017 December 31, 2016 (In millions) Credit Amortized Fair Credit Amortized Fair Japan National Government (1) A $47,637 $55,444 A $42,931 $51,345 (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 Nine Months Ended (In millions) 2017 2016 2017 2016 Realized investment gains (losses): Fixed maturities: Available for sale: Gross gains from sales $ 10 $ 2 $ 27 $ 10 Gross losses from sales (8 ) (22 ) (38 ) (38 ) Net gains (losses) from redemptions 14 1 (24 ) 88 Other-than-temporary impairment losses (2 ) (1 ) (9 ) (23 ) Total fixed maturities 14 (20 ) (44 ) 37 Perpetual securities: Available for sale: Net gains (losses) from redemptions 0 0 4 40 Other-than-temporary impairment losses 0 0 0 (2 ) Total perpetual securities 0 0 4 38 Equity securities: Gross gains from sales 54 5 102 10 Gross losses from sales (9 ) 0 (11 ) (10 ) Other-than-temporary impairment losses (6 ) (22 ) (18 ) (46 ) Total equity securities 39 (17 ) 73 (46 ) Derivatives and other: Derivative gains (losses) (40 ) (107 ) (143 ) (278 ) Foreign currency gains (losses) 17 (20 ) (56 ) (109 ) Total derivatives and other (23 ) (127 ) (199 ) (387 ) Total realized investment gains (losses) $ 30 $ (164 ) $ (166 ) $ (358 ) Prior year foreign currency transaction gains and losses have been reclassified to conform to current-year reporting classifications
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 investment securities was as follows: (In millions) September 30, 2017 December 31, Unrealized gains (losses) on securities available for sale $ 8,602 $ 7,630 Deferred income taxes (3,165 ) (2,825 ) Shareholders’ equity, unrealized gains (losses) on investment securities $ 5,437 $ 4,805
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. September 30, 2017 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed Maturities: Japan government and Yen-denominated $ 6,404 $ 423 $ 6,208 $ 399 $ 196 $ 24 Municipalities: Yen-denominated 152 15 62 3 90 12 Public utilities: U.S. dollar-denominated 879 34 252 4 627 30 Yen-denominated 95 7 69 6 26 1 Sovereign and supranational: Yen-denominated 352 3 352 3 0 0 Banks/financial institutions: U.S. dollar-denominated 188 7 145 3 43 4 Yen-denominated 1,616 77 637 29 979 48 Other corporate: U.S. dollar-denominated 7,886 462 2,803 52 5,083 410 Yen-denominated 424 25 386 24 38 1 Total fixed maturities 17,996 1,053 10,914 523 7,082 530 Perpetual securities: Yen-denominated 340 32 0 0 340 32 Total perpetual securities 340 32 0 0 340 32 Equity securities: U.S. dollar-denominated 58 6 50 5 8 1 Yen-denominated 72 2 67 1 5 1 Total equity securities 130 8 117 6 13 2 Total $ 18,466 $ 1,093 $ 11,031 $ 529 $ 7,435 $ 564 December 31, 2016 Total Less than 12 months 12 months or longer (In millions) Fair Unrealized Fair Unrealized Fair Unrealized Fixed Maturities: Japan government and Yen-denominated $ 3,958 $ 160 $ 3,958 $ 160 $ 0 $ 0 Municipalities: U.S. dollar-denominated 44 8 0 0 44 8 Yen-denominated 105 8 105 8 0 0 Mortgage- and asset- Yen-denominated 713 8 713 8 0 0 Public utilities: U.S. dollar-denominated 1,265 60 790 32 475 28 Yen-denominated 635 26 347 14 288 12 Sovereign and supranational: Yen-denominated 244 13 38 5 206 8 Banks/financial institutions: U.S. dollar-denominated 268 16 238 10 30 6 Yen-denominated 1,521 100 636 19 885 81 Other corporate: U.S. dollar-denominated 10,462 690 7,252 346 3,210 344 Yen-denominated 321 10 321 10 0 0 Total fixed maturities 19,536 1,099 14,398 612 5,138 487 Perpetual securities: Yen-denominated 479 49 85 1 394 48 Total perpetual securities 479 49 85 1 394 48 Equity securities: U.S. dollar-denominated 211 6 211 6 0 0 Yen-denominated 49 2 49 2 0 0 Total equity securities 260 8 260 8 0 0 Total $ 20,275 $ 1,156 $ 14,743 $ 621 $ 5,532 $ 535
Other Investments	The table below reflects the composition of the carrying value for other investments as of the periods presented. (In millions) September 30, 2017 December 31, 2016 Other investments: Commercial mortgage loans $ 1,199 $ 855 Middle market loans 798 319 Policy loans 207 184 Short-term investments 57 89 Other 97 3 Total other investments $ 2,358 $ 1,450
Securities Lending Transactions Accounted for as Secured Borrowings	Details of the Company's securities lending activities were as follows: Securities Lending Transactions Accounted for as Secured Borrowings September 30, 2017 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Total Securities lending transactions: Public utilities $ 37 $ 0 $ 37 Banks/financial institutions 37 0 37 Other corporate 434 0 434 Equity securities 14 0 14 Total borrowings $ 522 $ 0 $ 522 Gross amount of recognized liabilities for securities lending transactions $ 522 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 0 (1) These securities are pledged as collateral under the Company's U.S. securities lending program and can be called at its discretion; therefore, they are classified as Overnight and Continuous. Securities Lending Transactions Accounted for as Secured Borrowings December 31, 2016 Remaining Contractual Maturity of the Agreements (In millions) Overnight (1) Up to 30 Total Securities lending transactions: Public utilities $ 62 $ 0 $ 62 Banks/financial institutions 34 0 34 Other corporate 430 0 430 Total borrowings $ 526 $ 0 $ 526 Gross amount of recognized liabilities for securities lending transactions $ 526 Amounts related to agreements not included in offsetting disclosure in Note 4 $ 0 (1) These securities are pledged as collateral under the Company's U.S. securities lending program and can be called at its 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 September 30, 2017 December 31, 2016 (In millions) Cost or Amortized Fair Cost or Amortized Fair Assets: Fixed maturities, available for sale $ 4,274 $ 5,224 $ 4,168 $ 4,982 Perpetual securities, available for sale 239 211 237 208 Equity securities 595 690 972 1,044 Other investments (1) 1,500 1,491 819 789 Other assets (2) 148 148 127 127 Total assets of consolidated VIEs $ 6,756 $ 7,764 $ 6,323 $ 7,150 Liabilities: Other liabilities (2) $ 132 $ 132 $ 146 $ 146 Total liabilities of consolidated VIEs $ 132 $ 132 $ 146 $ 146 (1) Consists of CMLs, MMLs, and alternative investments in limited partnerships (2) Consists entirely of derivatives
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 September 30, 2017 December 31, 2016 (In millions) Amortized Fair Amortized Fair Assets: Fixed maturities, available for sale $ 4,766 $ 5,439 $ 4,729 $ 5,261 Perpetual securities, available for sale 177 220 172 200 Fixed maturities, held to maturity 2,645 3,047 2,563 2,948 Other investments 50 50 1 1 Total investments in VIEs not consolidated $ 7,638 $ 8,756 $ 7,465 $ 8,410

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	September 30, 2017 December 31, 2016 (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 $ 75 $ 0 $ (9 ) $ 75 $ 0 $ (10 ) Total cash flow hedges 75 0 (9 ) 75 0 (10 ) Fair value hedges: Foreign currency forwards 9,278 0 (411 ) 10,965 0 (759 ) Foreign currency options 5,660 0 (20 ) 4,224 2 (32 ) Total fair value hedges 14,938 0 (431 ) 15,189 2 (791 ) Net investment hedge: Foreign currency forwards 48 1 0 209 5 (2 ) Foreign currency options 564 17 (4 ) 843 41 (17 ) Total net investment hedge 612 18 (4 ) 1,052 46 (19 ) Non-qualifying strategies: Foreign currency swaps 5,387 301 (187 ) 6,266 490 (220 ) Foreign currency forwards 7,124 159 (343 ) 21,218 667 (956 ) Foreign currency options 25 0 0 41 0 (2 ) Credit default swaps 89 1 0 86 2 0 Total non-qualifying strategies 12,625 461 (530 ) 27,611 1,159 (1,178 ) Total derivatives $ 28,250 $ 479 $ (974 ) $ 43,927 $ 1,207 $ (1,998 ) Balance Sheet Location Other assets $ 9,509 $ 479 $ 0 $ 18,329 $ 1,207 $ 0 Other liabilities 18,741 0 (974 ) 25,598 0 (1,998 ) Total derivatives $ 28,250 $ 479 $ (974 ) $ 43,927 $ 1,207 $ (1,998 )
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) Gains (Losses) Gains (Losses) Ineffectiveness Three Months Ended September 30, 2017: Foreign currency Fixed-maturity and equity securities $ (114 ) $ (53 ) $ (61 ) $ 61 $ 0 Foreign currency Fixed-maturity securities (14 ) (14 ) 0 0 0 Nine Months Ended September 30, 2017: Foreign currency forwards Fixed-maturity and equity securities $ 193 $ (151 ) $ 344 $ (326 ) $ 18 Foreign currency options Fixed-maturity securities 3 (8 ) 11 (10 ) 1 Three Months Ended September 30, 2016: Foreign currency Fixed-maturity and equity securities $ 90 $ (186 ) $ 276 $ (288 ) $ (12 ) Foreign currency options Fixed-maturity securities (4 ) (4 ) 0 0 0 Nine Months Ended September 30, 2016: Foreign currency forwards Fixed-maturity and equity securities $ 2,103 $ (278 ) $ 2,381 $ (2,406 ) $ (25 ) Foreign currency options Fixed-maturity securities 2 2 0 0 0
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 September 30, Nine Months Ended September 30, 2017 2016 2017 2016 (In millions) Realized Investment Other (1) Realized Investment Other (1) Realized Investment Other (1) Realized Investment Other (1) Qualifying hedges: Cash flow hedges: Foreign currency swaps $ 0 $ (1 ) $ 0 $ 0 $ 0 $ 0 $ 1 $ 11 Total cash flow hedges 0 (1 ) 0 0 0 0 1 11 Fair value hedges: Foreign currency forwards (2) (53 ) 0 (198 ) 0 (133 ) 0 (303 ) 0 Foreign currency options (2) (14 ) 0 (4 ) 0 (7 ) 0 2 0 Total fair value hedges (67 ) 0 (202 ) 0 (140 ) 0 (301 ) 0 Net investment hedge: Non- derivative hedging instruments 0 5 0 (2 ) 0 (13 ) 0 (39 ) Foreign currency forwards 0 4 0 (28 ) 0 (24 ) 0 (161 ) Foreign currency options 0 (5 ) 0 31 0 3 0 0 Total net investment hedge 0 4 0 1 0 (34 ) 0 (200 ) Non-qualifying strategies: Foreign currency swaps 17 0 (51 ) 0 43 0 (145 ) 0 Foreign currency forwards 10 0 144 0 (46 ) 0 165 0 Credit default swaps 0 0 2 0 0 0 2 0 Total non- qualifying strategies 27 0 95 0 (3 ) 0 22 0 Total $ (40 ) $ 3 $ (107 ) $ 1 $ (143 ) $ (34 ) $ (278 ) $ (189 ) (1) Cash flow hedge items 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). (2) Impact shown net of effect of hedged items (see Fair Value Hedges section of this Note 4 for further detail)
Fair Value and Notional Amount of Derivatives with Counterparty Credit Risk	The counterparties to these derivatives are financial institutions with the following credit ratings: September 30, 2017 December 31, 2016 (In millions) Notional Amount Asset Derivatives Liability Derivatives Notional Amount Asset Derivatives Liability Derivatives Counterparties' credit rating: AA $ 5,553 $ 90 $ (189 ) $ 6,844 $ 247 $ (308 ) A 22,257 381 (718 ) 36,019 900 (1,621 ) BBB 440 8 (67 ) 1,064 60 (69 ) Total $ 28,250 $ 479 $ (974 ) $ 43,927 $ 1,207 $ (1,998 )
Offsetting Assets	Offsetting of Financial Assets and Derivative Asset September 30, 2017 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 $ 331 $ 0 $ 331 $ (219 ) $ 0 $ (112 ) $ 0 Derivative assets not subject to a master netting agreement or offsetting arrangement 148 148 148 Total derivative assets 479 0 479 (219 ) 0 (112 ) 148 Securities lending and similar arrangements 509 0 509 0 0 (509 ) 0 Total $ 988 $ 0 $ 988 $ (219 ) $ 0 $ (621 ) $ 148 December 31, 2016 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 $ 1,080 $ 0 $ 1,080 $ (698 ) $ 0 $ (382 ) $ 0 Derivative assets not subject to a master netting agreement or offsetting arrangement 127 127 127 Total derivative assets 1,207 0 1,207 (698 ) 0 (382 ) 127 Securities lending and similar arrangements 513 0 513 0 0 (513 ) 0 Total $ 1,720 $ 0 $ 1,720 $ (698 ) $ 0 $ (895 ) $ 127
Offsetting Liabilities	Offsetting of Financial Liabilities and Derivative Liabilities September 30, 2017 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 $ (842 ) $ 0 $ (842 ) $ 219 $ 611 $ 7 $ (5 ) Derivative liabilities not subject to a master netting agreement or offsetting arrangement (132 ) (132 ) (132 ) Total derivative liabilities (974 ) 0 (974 ) 219 611 7 (137 ) Securities lending and similar arrangements (522 ) 0 (522 ) 509 0 0 (13 ) Total $ (1,496 ) $ 0 $ (1,496 ) $ 728 $ 611 $ 7 $ (150 ) December 31, 2016 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 $ (1,852 ) $ 0 $ (1,852 ) $ 698 $ 1,130 $ 21 $ (3 ) Derivative liabilities not subject to a master netting agreement or offsetting arrangement (146 ) (146 ) (146 ) Total derivative liabilities (1,998 ) 0 (1,998 ) 698 1,130 21 (149 ) Securities lending and similar arrangements (526 ) 0 (526 ) 513 0 0 (13 ) Total $ (2,524 ) $ 0 $ (2,524 ) $ 1,211 $ 1,130 $ 21 $ (162 )

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
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. September 30, 2017 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturities: Government and agencies $ 29,067 $ 971 $ 0 $ 30,038 Municipalities 0 1,292 0 1,292 Mortgage- and asset-backed securities 0 278 178 456 Public utilities 0 7,938 77 8,015 Sovereign and supranational 0 2,029 0 2,029 Banks/financial institutions 0 6,985 25 7,010 Other corporate 0 31,473 102 31,575 Total fixed maturities 29,067 50,966 382 80,415 Perpetual securities: Banks/financial institutions 0 1,627 0 1,627 Other corporate 0 236 0 236 Total perpetual securities 0 1,863 0 1,863 Equity securities 905 5 18 928 Other assets: Foreign currency swaps 0 154 147 301 Foreign currency forwards 0 160 0 160 Foreign currency options 0 17 0 17 Credit default swaps 0 0 1 1 Total other assets 0 331 148 479 Other investments 57 0 0 57 Cash and cash equivalents 4,927 0 0 4,927 Total assets $ 34,956 $ 53,165 $ 548 $ 88,669 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 64 $ 132 $ 196 Foreign currency forwards 0 754 0 754 Foreign currency options 0 24 0 24 Total liabilities $ 0 $ 842 $ 132 $ 974 December 31, 2016 (In millions) Quoted Prices in Significant Significant Total Assets: Securities available for sale, carried at Fixed maturities: Government and agencies $ 25,387 $ 827 $ 0 $ 26,214 Municipalities 0 1,295 0 1,295 Mortgage- and asset-backed securities 0 1,139 198 1,337 Public utilities 0 7,667 16 7,683 Sovereign and supranational 0 1,469 0 1,469 Banks/financial institutions 0 6,038 25 6,063 Other corporate 0 29,699 0 29,699 Total fixed maturities 25,387 48,134 239 73,760 Perpetual securities: Banks/financial institutions 0 1,420 0 1,420 Other corporate 0 213 0 213 Total perpetual securities 0 1,633 0 1,633 Equity securities 1,300 6 3 1,309 Other assets: Foreign currency swaps 0 365 125 490 Foreign currency forwards 0 672 0 672 Foreign currency options 0 43 0 43 Credit default swaps 0 0 2 2 Total other assets 0 1,080 127 1,207 Other investments 276 0 0 276 Cash and cash equivalents 4,859 0 0 4,859 Total assets $ 31,822 $ 50,853 $ 369 $ 83,044 Liabilities: Other liabilities: Foreign currency swaps $ 0 $ 84 $ 146 $ 230 Foreign currency forwards 0 1,717 0 1,717 Foreign currency options 0 51 0 51 Total liabilities $ 0 $ 1,852 $ 146 $ 1,998
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. September 30, 2017 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturities: Government and agencies $ 21,385 $ 26,455 $ 0 $ 0 $ 26,455 Municipalities 359 0 463 0 463 Mortgage and asset-backed 27 0 9 20 29 Public utilities 3,308 0 3,734 0 3,734 Sovereign and 1,527 0 1,846 0 1,846 Banks/financial institutions 2,700 0 2,887 0 2,887 Other corporate 2,692 0 3,185 0 3,185 Other investments (1) 2,011 0 15 1,985 2,000 Total assets $ 34,009 $ 26,455 $ 12,139 $ 2,005 $ 40,599 Liabilities: Other policyholders’ funds $ 6,967 $ 0 $ 0 $ 6,849 $ 6,849 Notes payable 5,230 506 4,780 265 5,551 Total liabilities $ 12,197 $ 506 $ 4,780 $ 7,114 $ 12,400 (1) Excludes policy loans of $207 and equity method investments of $83 , at carrying value December 31, 2016 (In millions) Carrying Quoted Prices in Significant Significant Total Assets: Securities held to maturity, Fixed maturities: Government and agencies $ 20,702 $ 26,040 $ 0 $ 0 $ 26,040 Municipalities 350 0 457 0 457 Mortgage and asset-backed 30 0 10 22 32 Public utilities 3,201 0 3,536 0 3,536 Sovereign and 2,602 0 2,877 0 2,877 Banks/financial institutions 3,731 0 3,900 0 3,900 Other corporate 2,734 0 3,179 0 3,179 Other investments 1,174 0 0 1,142 1,142 Total assets $ 34,524 $ 26,040 $ 13,959 $ 1,164 $ 41,163 Liabilities: Other policyholders’ funds $ 6,659 $ 0 $ 0 $ 6,540 $ 6,540 Notes payable 5,339 0 0 5,530 5,530 Total liabilities $ 11,998 $ 0 $ 0 $ 12,070 $ 12,070
Fair Value Assets Available-for-Sale Securities Primary Pricing Sources	The following tables present the pricing sources for the fair values of the Company's fixed maturities, perpetual securities, and equity securities. September 30, 2017 (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 maturities: Government and agencies: Third party pricing vendor $ 29,067 $ 971 $ 0 $ 30,038 Total government and agencies 29,067 971 0 30,038 Municipalities: Third party pricing vendor 0 1,292 0 1,292 Total municipalities 0 1,292 0 1,292 Mortgage- and asset-backed securities: Third party pricing vendor 0 278 0 278 Broker/other 0 0 178 178 Total mortgage- and asset-backed securities 0 278 178 456 Public utilities: Third party pricing vendor 0 7,938 0 7,938 Broker/other 0 0 77 77 Total public utilities 0 7,938 77 8,015 Sovereign and supranational: Third party pricing vendor 0 2,029 0 2,029 Total sovereign and supranational 0 2,029 0 2,029 Banks/financial institutions: Third party pricing vendor 0 6,985 0 6,985 Broker/other 0 0 25 25 Total banks/financial institutions 0 6,985 25 7,010 Other corporate: Third party pricing vendor 0 31,473 0 31,473 Broker/other 0 0 102 102 Total other corporate 0 31,473 102 31,575 Total fixed maturities 29,067 50,966 382 80,415 Perpetual securities: Banks/financial institutions: Third party pricing vendor 0 1,627 0 1,627 Total banks/financial institutions 0 1,627 0 1,627 Other corporate: Third party pricing vendor 0 236 0 236 Total other corporate 0 236 0 236 Total perpetual securities 0 1,863 0 1,863 Equity securities: Third party pricing vendor 905 5 0 910 Broker/other 0 0 18 18 Total equity securities 905 5 18 928 Total securities available for sale $ 29,972 $ 52,834 $ 400 $ 83,206 December 31, 2016 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities available for sale, carried at fair value: Fixed maturities: Government and agencies: Third party pricing vendor $ 25,387 $ 827 $ 0 $ 26,214 Total government and agencies 25,387 827 0 26,214 Municipalities: Third party pricing vendor 0 1,295 0 1,295 Total municipalities 0 1,295 0 1,295 Mortgage- and asset-backed securities: Third party pricing vendor 0 1,139 0 1,139 Broker/other 0 0 198 198 Total mortgage- and asset-backed securities 0 1,139 198 1,337 Public utilities: Third party pricing vendor 0 7,667 0 7,667 Broker/other 0 0 16 16 Total public utilities 0 7,667 16 7,683 Sovereign and supranational: Third party pricing vendor 0 1,469 0 1,469 Total sovereign and supranational 0 1,469 0 1,469 Banks/financial institutions: Third party pricing vendor 0 6,038 0 6,038 Broker/other 0 0 25 25 Total banks/financial institutions 0 6,038 25 6,063 Other corporate: Third party pricing vendor 0 29,699 0 29,699 Total other corporate 0 29,699 0 29,699 Total fixed maturities 25,387 48,134 239 73,760 Perpetual securities: Banks/financial institutions: Third party pricing vendor 0 1,420 0 1,420 Total banks/financial institutions 0 1,420 0 1,420 Other corporate: Third party pricing vendor 0 213 0 213 Total other corporate 0 213 0 213 Total perpetual securities 0 1,633 0 1,633 Equity securities: Third party pricing vendor 1,300 6 0 1,306 Broker/other 0 0 3 3 Total equity securities 1,300 6 3 1,309 Total securities available for sale $ 26,687 $ 49,773 $ 242 $ 76,702
Fair Value Assets Held-To-Maturity Securities Primary Pricing Sources	September 30, 2017 (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 maturities: Government and agencies: Third party pricing vendor $ 26,455 $ 0 $ 0 $ 26,455 Total government and agencies 26,455 0 0 26,455 Municipalities: Third party pricing vendor 0 463 0 463 Total municipalities 0 463 0 463 Mortgage- and asset-backed securities: Third party pricing vendor 0 9 0 9 Broker/other 0 0 20 20 Total mortgage- and asset-backed securities 0 9 20 29 Public utilities: Third party pricing vendor 0 3,734 0 3,734 Total public utilities 0 3,734 0 3,734 Sovereign and supranational: Third party pricing vendor 0 1,846 0 1,846 Total sovereign and supranational 0 1,846 0 1,846 Banks/financial institutions: Third party pricing vendor 0 2,887 0 2,887 Total banks/financial institutions 0 2,887 0 2,887 Other corporate: Third party pricing vendor 0 3,185 0 3,185 Total other corporate 0 3,185 0 3,185 Total securities held to maturity $ 26,455 $ 12,124 $ 20 $ 38,599 December 31, 2016 (In millions) Quoted Prices in Active Markets Significant Observable Significant Unobservable Inputs Total Securities held to maturity, carried at amortized cost: Fixed maturities: Government and agencies: Third party pricing vendor $ 26,040 $ 0 $ 0 $ 26,040 Total government and agencies 26,040 0 0 26,040 Municipalities: Third party pricing vendor 0 457 0 457 Total municipalities 0 457 0 457 Mortgage- and asset-backed securities: Third party pricing vendor 0 10 0 10 Broker/other 0 0 22 22 Total mortgage- and asset-backed securities 0 10 22 32 Public utilities: Third party pricing vendor 0 3,536 0 3,536 Total public utilities 0 3,536 0 3,536 Sovereign and supranational: Third party pricing vendor 0 2,877 0 2,877 Total sovereign and supranational 0 2,877 0 2,877 Banks/financial institutions: Third party pricing vendor 0 3,900 0 3,900 Total banks/financial institutions 0 3,900 0 3,900 Other corporate: Third party pricing vendor 0 3,179 0 3,179 Total other corporate 0 3,179 0 3,179 Total securities held to maturity $ 26,040 $ 13,959 $ 22 $ 40,021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	Transfers between Hierarchy Levels and Level 3 Rollforward During the three- and nine -month periods ended September 30, 2017 and 2016 , 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 available-for-sale investments and derivatives classified as Level 3. Three Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 188 $ 53 $ 25 $ 77 $ 14 $ 7 $ 2 $ 366 Realized investment gains (losses) included in earnings 0 0 0 0 0 8 (1 ) 7 Unrealized gains (losses) included in other comprehensive income (loss) (2 ) 0 0 1 0 0 0 (1 ) Purchases, issuances, sales and settlements: Purchases 0 24 0 25 4 0 0 53 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 (1 ) 0 0 0 (1 ) Settlements (8 ) 0 0 0 0 0 0 (8 ) 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 $ 178 $ 77 $ 25 $ 102 $ 18 $ 15 $ 1 $ 416 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ 8 $ (1 ) $ 7 (1) Derivative assets and liabilities are presented net Three Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 252 $ 0 $ 26 $ 0 $ 3 $ 59 $ 1 $ 341 Realized investment gains (losses) included in 0 0 0 0 0 (18 ) 2 (16 ) Unrealized gains (losses) included in other 1 0 0 0 0 0 0 1 Purchases, issuances, sales and settlements: Purchases 0 0 0 0 0 0 0 0 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 0 0 0 0 0 Settlements (13 ) 0 0 0 0 0 0 (13 ) 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 $ 240 $ 0 $ 26 $ 0 $ 3 $ 41 $ 3 $ 313 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ (18 ) $ 2 $ (16 ) (1) Derivative assets and liabilities are presented net Nine Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 198 $ 16 $ 25 $ 0 $ 3 $ (21 ) $ 2 $ 223 Realized investment gains (losses) included 0 0 0 0 0 36 (1 ) 35 Unrealized gains (losses) included in other 4 0 0 3 0 0 0 7 Purchases, issuances, sales and settlements: Purchases 0 61 0 100 16 0 0 177 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 (1 ) (1 ) 0 0 (2 ) Settlements (24 ) 0 0 0 0 0 0 (24 ) 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 $ 178 $ 77 $ 25 $ 102 $ 18 $ 15 $ 1 $ 416 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ 36 $ (1 ) $ 35 (1) Derivative assets and liabilities are presented net Nine Months Ended Fixed Maturities Equity Derivatives (1) (In millions) Mortgage- Public Banks/ Other Foreign Credit Total Balance, beginning of period $ 220 $ 0 $ 26 $ 0 $ 3 $ (192 ) $ 1 $ 58 Realized investment gains (losses) included in earnings 0 0 0 0 0 250 2 252 Unrealized gains (losses) included in other comprehensive income (loss) 48 0 0 0 0 (16 ) 0 32 Purchases, issuances, sales and settlements: Purchases 0 0 0 0 0 0 0 0 Issuances 0 0 0 0 0 0 0 0 Sales 0 0 0 0 0 0 0 0 Settlements (28 ) 0 0 0 0 (1 ) 0 (29 ) 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 $ 240 $ 0 $ 26 $ 0 $ 3 $ 41 $ 3 $ 313 Changes in unrealized gains (losses) relating $ 0 $ 0 $ 0 $ 0 $ 0 $ 250 $ 2 $ 252 (1) Derivative assets and liabilities are presented net
Fair Value Inputs Assets Quantitative Information	December 31, 2016 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturities: Mortgage- and asset-backed securities $ 198 Consensus pricing Offered quotes N/A (d) Public utilities 16 Discounted cash flow Historical volatility N/A (d) Banks/financial institutions 25 Consensus pricing Offered quotes N/A (d) Equity securities 3 Net asset value Offered quotes $1-$701 ($8) Other assets: Foreign currency swaps 16 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 17 - 172 bps Foreign exchange rates 21.47% (c) 29 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 16 - 88 bps 80 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) Foreign exchange rates 21.47% (c) Credit default swaps 2 Discounted cash flow Base correlation 52.18% - 56.07% (e) CDS spreads 54 bps Recovery rate 36.69% Total assets $ 369 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate (d) 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. (e) Range of base correlation for the Company's bespoke tranche for attachment and detachment points corresponding to market indices The following tables summarize the significant unobservable inputs used in the valuation of the Company's Level 3 available-for-sale investments and derivatives. Included in the tables are the inputs or range of possible inputs that have an effect on the overall valuation of the financial instruments. September 30, 2017 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Assets: Securities available for sale, carried at fair value: Fixed maturities: Mortgage- and asset-backed securities $ 178 Consensus pricing Offered quotes N/A (d) Public utilities 77 Discounted cash flow Historical volatility N/A (d) Banks/financial institutions 25 Consensus pricing Offered quotes N/A (d) Other corporate 102 Discounted cash flow Historical volatility N/A (e) Equity securities 18 Net asset value Offered quotes $1 - $724 ($6) Other assets: Foreign currency swaps 27 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 11 - 116 bps Foreign exchange rates 21.00% (c) 45 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 11 - 83 bps 75 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) Foreign exchange rates 21.00% (c) Credit default swaps 1 Discounted cash flow Base correlation 62.73% - 66.88% (e) CDS spreads 19 bps Recovery rate 37.24% Total assets $ 548 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate (d) 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. (e) Range of base correlation for the Company's bespoke tranche for attachment and detachment points corresponding to market indices.
Fair Value Inputs Liabilities Quantitative Information	December 31, 2016 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Liabilities: Other liabilities: Foreign currency swaps $ 113 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 17 - 172 bps Foreign exchange rates 21.47% (c) 23 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) CDS spreads 24 - 216 bps 10 Discounted cash flow Interest rates (USD) 2.34% - 2.59% (a) Interest rates (JPY) .22% - .80% (b) Foreign exchange rates 21.47% (c) Total liabilities $ 146 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate September 30, 2017 (In millions) Fair Value Valuation Technique(s) Unobservable Input Range Liabilities: Other liabilities: Foreign currency swaps $ 112 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 11 - 116 bps Foreign exchange rates 21.00% (c) 11 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) CDS spreads 9 - 120 bps 9 Discounted cash flow Interest rates (USD) 2.29% - 2.53% (a) Interest rates (JPY) .26% - .86% (b) Foreign exchange rates 21.00% (c) Total liabilities $ 132 (a) Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps (b) Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps (c) Based on 10 year volatility of JPY/USD exchange rate

POLICY LIABILITIES (Tables)

POLICY LIABILITIES (Tables)	9 Months Ended
	Sep. 30, 2017
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 Nine Months Ended (In millions) 2017 2016 2017 2016 Unpaid supplemental health claims, beginning of period $ 3,872 $ 3,941 $ 3,707 $ 3,548 Less reinsurance recoverables 30 30 27 26 Net balance, beginning of period 3,842 3,911 3,680 3,522 Add claims incurred during the period related to: Current year 1,759 1,843 5,278 5,309 Prior years (126 ) (148 ) (386 ) (374 ) Total incurred 1,633 1,695 4,892 4,935 Less claims paid during the period on claims incurred during: Current year 1,357 1,462 3,074 3,160 Prior years 234 232 1,697 1,722 Total paid 1,591 1,694 4,771 4,882 Effect of foreign exchange rate changes on unpaid claims (14 ) 42 69 379 Net balance, end of period 3,870 3,954 3,870 3,954 Add reinsurance recoverables 30 31 30 31 Unpaid supplemental health claims, end of period 3,900 3,985 3,900 3,985 Unpaid life claims, end of period 468 361 468 361 Total liability for unpaid policy claims $ 4,368 $ 4,346 $ 4,368 $ 4,346

REINSURANCE (Tables)

REINSURANCE (Tables)	9 Months Ended
	Sep. 30, 2017
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 Nine Months Ended (In millions) 2017 2016 2017 2016 Direct premium income $ 4,734 $ 5,119 $ 14,210 $ 14,724 Ceded to other companies: Ceded Aflac Japan closed blocks (130 ) (148 ) (390 ) (423 ) Other (12 ) (13 ) (37 ) (37 ) Assumed from other companies: Retrocession activities 54 62 163 177 Other 2 2 5 6 Net premium income $ 4,648 $ 5,022 $ 13,951 $ 14,447 Direct benefits and claims $ 3,157 $ 3,463 $ 9,403 $ 9,898 Ceded benefits and change in reserves for future benefits: Ceded Aflac Japan closed blocks (118 ) (135 ) (359 ) (385 ) Eliminations 13 16 39 44 Other (9 ) (10 ) (31 ) (26 ) Assumed from other companies: Retrocession activities 53 59 159 168 Eliminations (13 ) (16 ) (39 ) (44 ) Other 0 1 2 2 Benefits and claims, net $ 3,083 $ 3,378 $ 9,174 $ 9,657

NOTES PAYABLE (Tables)

NOTES PAYABLE (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	A summary of notes payable follows: (In millions) September 30, 2017 December 31, 2016 2.65% senior notes paid February 2017 $ 0 $ 649 2.40% senior notes due March 2020 545 547 4.00% senior notes due February 2022 346 348 3.625% senior notes due June 2023 694 696 3.625% senior notes due November 2024 743 745 3.25% senior notes due March 2025 445 445 2.875% senior notes due October 2026 298 298 6.90% senior notes due December 2039 221 220 6.45% senior notes due August 2040 256 254 4.00% senior notes due October 2046 394 394 5.50% subordinated debentures due September 2052 494 486 Yen-denominated senior notes: .932% senior notes due January 2027 (principal amount 60.0 billion yen) 529 0 Yen-denominated loans: Variable interest rate loan due September 2021 (.31% in 2017 and 2016, principal amount 5.0 billion yen) 44 43 Variable interest rate loan due September 2023 (.46% in 2017 and 2016, principal amount 25.0 billion yen) 221 214 Capitalized lease obligations payable through 2024 18 21 Total notes payable $ 5,248 $ 5,360 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.

SHAREHOLDERS' EQUITY (Tables)

SHAREHOLDERS' EQUITY (Tables)	9 Months Ended
	Sep. 30, 2017
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 nine -month periods ended September 30 . (In thousands of shares) 2017 2016 Common stock - issued: Balance, beginning of period 671,249 669,723 Exercise of stock options and issuance of restricted shares 1,420 1,261 Balance, end of period 672,669 670,984 Treasury stock: Balance, beginning of period 265,439 245,343 Purchases of treasury stock: Open market 13,898 18,774 Other 435 329 Dispositions of treasury stock: Shares issued to AFL Stock Plan (696 ) (822 ) Exercise of stock options (263 ) (554 ) Other (19 ) (107 ) Balance, end of period 278,794 262,963 Shares outstanding, end of period 393,875 408,021
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 Nine Months Ended (In thousands) 2017 2016 2017 2016 Anti-dilutive share-based awards 266 109 335 1,162
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 Liability Adjustment Total Balance, beginning of period $ (1,580 ) $ 5,173 $ (23 ) $ (169 ) $ 3,401 Other comprehensive (135 ) 296 0 (2 ) 159 Amounts reclassified from 0 (32 ) 0 3 (29 ) Net current-period other (135 ) 264 0 1 130 Balance, end of period $ (1,715 ) $ 5,437 $ (23 ) $ (168 ) $ 3,531 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 $ (847 ) $ 6,441 $ (19 ) $ (143 ) $ 5,432 Other comprehensive 253 (342 ) 0 (1 ) (90 ) Amounts reclassified from 0 21 0 1 22 Net current-period other 253 (321 ) 0 0 (68 ) Balance, end of period $ (594 ) $ 6,120 $ (19 ) $ (143 ) $ 5,364 All amounts in the table above are net of tax. Nine Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Total Balance, beginning of period $ (1,983 ) $ 4,805 $ (24 ) $ (168 ) $ 2,630 Other comprehensive 268 653 1 (8 ) 914 Amounts reclassified from 0 (21 ) 0 8 (13 ) Net current-period other 268 632 1 0 901 Balance, end of period $ (1,715 ) $ 5,437 $ (23 ) $ (168 ) $ 3,531 All amounts in the table above are net of tax. Nine Months Ended (In millions) Unrealized Foreign Unrealized Unrealized Pension Liability Adjustment Total Balance, beginning of period $ (2,196 ) $ 2,986 $ (26 ) $ (139 ) $ 625 Other comprehensive 1,602 3,155 7 (7 ) 4,757 Amounts reclassified from 0 (21 ) 0 3 (18 ) Net current-period other 1,602 3,134 7 (4 ) 4,739 Balance, end of period $ (594 ) $ 6,120 $ (19 ) $ (143 ) $ 5,364 All amounts in the table above are net of tax.
Reclassification Out Of Accumulated Other Comprehensive Income	The tables below summarize the amounts reclassified from each component of accumulated other comprehensive income based on source 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 $ 56 Sales and redemptions (6 ) Other-than-temporary impairment 50 Total before tax (18 ) Tax (expense) or benefit (1) $ 32 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 $ 29 Net of tax (1) Based on 35% 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 $ (11 ) Sales and redemptions (22 ) Other-than-temporary impairment (33 ) Total before tax 12 Tax (expense) or benefit (1) $ (21 ) Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (4 ) Acquisition and operating expenses (2) Prior service (cost) credit 2 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (1 ) Net of tax Total reclassifications for the period $ (22 ) Net of tax (1) Based on 35% 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) Nine 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 $ 56 Sales and redemptions (23 ) Other-than-temporary impairment 33 Total before tax (12 ) Tax (expense) or benefit (1) $ 21 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (12 ) Acquisition and operating expenses (2) Prior service (cost) credit 0 Acquisition and operating expenses (2) 4 Tax (expense) or benefit (1) $ (8 ) Net of tax Total reclassifications for the period $ 13 Net of tax (1) Based on 35% 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) Nine 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 $ 102 Sales and redemptions (69 ) Other-than-temporary impairment 33 Total before tax (12 ) Tax (expense) or benefit (1) $ 21 Net of tax Amortization of defined benefit pension items: Actuarial gains (losses) $ (12 ) Acquisition and operating expenses (2) Prior service (cost) credit 8 Acquisition and operating expenses (2) 1 Tax (expense) or benefit (1) $ (3 ) Net of tax Total reclassifications for the period $ 18 Net of tax (1) Based on 35% 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).

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 . Stock Weighted-Average Aggregate Weighted-Average Outstanding 4,181 5.4 $ 108 $ 55.61 Exercisable 2,563 3.6 79 50.73
Schedule of Nonvested Restricted Stock Units Activity	The following table summarizes restricted stock activity during the nine -month period ended September 30 . (In thousands of shares) Shares Weighted-Average Grant-Date Fair Value Per Share Restricted stock at December 31, 2016 1,868 $ 61.76 Granted in 2017 555 72.85 Canceled in 2017 (79 ) 64.22 Vested in 2017 (486 ) 62.22 Restricted stock at September 30, 2017 1,858 $ 64.71

BENEFIT PLANS (Tables)

BENEFIT PLANS (Tables)	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Schedule of Net Benefit Costs	Pension and other postretirement benefit expenses, included in acquisition and operating expenses in the consolidated statement of earnings, included the following components: Three Months Ended September 30, Pension Benefits Other Japan U.S. Postretirement Benefits (In millions) 2017 2016 2017 2016 2017 2016 Components of net periodic Service cost $ 4 $ 4 $ 6 $ 5 $ 0 $ 0 Interest cost 2 2 8 8 0 0 Expected return on plan (1 ) (1 ) (6 ) (6 ) 0 0 Amortization of net actuarial 1 0 3 4 0 0 Amortization of prior service 0 0 0 0 0 (2 ) Net periodic (benefit) cost $ 6 $ 5 $ 11 $ 11 $ 0 $ (2 ) Nine Months Ended September 30, Pension Benefits Other Japan U.S. Postretirement Benefits (In millions) 2017 2016 2017 2016 2017 2016 Components of net periodic Service cost $ 13 $ 12 $ 18 $ 17 $ 0 $ 0 Interest cost 5 5 24 24 1 1 Expected return on plan (3 ) (3 ) (17 ) (17 ) 0 0 Amortization of net actuarial 2 1 10 10 0 1 Amortization of prior service 0 0 0 0 0 (8 ) Net periodic (benefit) cost $ 17 $ 15 $ 35 $ 34 $ 1 $ (6 )

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Aflac Japan
Significant Accounting Policies [Line Items]
Aflac Japan's percentage of the Company's total revenues	69.00%	74.00%
Percentage of the Company Assets	83.00%		83.00%
Upper Limit
Significant Accounting Policies [Line Items]
Estimation of Percent of Leases Within Scope of the Guidance to Total Assets	1.00%
Estimation of Percent of Revenues Within Scope of the Guidance to Total Revenues	1.00%

BUSINESS SEGMENT INFORMATION -

BUSINESS SEGMENT INFORMATION - Operations by Segment - Revenues (Details) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)segment	Sep. 30, 2016USD ($)
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of Reportable Insurance Business Segments | segment				2
Net earned premiums		$ 4,648	$ 5,022	$ 13,951	$ 14,447
Net investment income		811	842	2,408	2,465
Total revenues		5,506	5,716	16,243	16,604
Total operating revenues		5,435	5,846	16,300	16,902
Realized investment gains (losses), non-operating	[1],[2],[3],[4],[5],[6]	71	(130)	(57)	(298)
Gain (loss) on change in fair value of derivative, interest rate component, operating		19	20	60	64
Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		3,200	3,596	9,616	10,177
Net investment income, less amortized hedge costs	[1]	561	607	1,676	1,802
Other income (loss)		11	10	31	29
Total revenues		3,772	4,213	11,323	12,008
Hedge costs		60	54	168	123
Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		1,393	1,365	4,172	4,093
Other income (loss)		1	1	3	5
Net investment income		181	176	539	526
Total revenues		1,575	1,542	4,714	4,624
Other business segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		69	71	204	207
Total Business Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		5,416	5,826	16,241	16,839
Corporate and eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		$ 19	$ 20	$ 59	$ 63
[1]	Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine-month periods ended September 30, 2017, and 2016, respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from net investment income when analyzing segment operations to conform to current year reporting.
[2]	Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine-month periods ended September 30, 2017, and 2016, respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from pretax operating earnings when analyzing segment operations to conform to current year reporting.
[3]	Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine-month periods ended September 30, 2017, and 2016, respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations
[4]	Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine-month periods ended September 30, 2017, and 2016, respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations
[5]	Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total earnings before income taxes.
[6]	Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total revenues

BUSINESS SEGMENT INFORMATION 34

BUSINESS SEGMENT INFORMATION - Operations by Segment - Pretax Earnings (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings		$ 1,014	$ 1,092	$ 3,114	$ 3,213
Realized investment gains (losses), non-operating	[1],[2],[3],[4],[5],[6]	71	(130)	(57)	(298)
Other non-operating income (loss)	[5]	(10)	1	(38)	(1)
Earnings before income taxes		1,075	963	3,019	2,914
Income taxes applicable to pretax operating earnings		338	379	1,031	1,112
Effect of foreign currency translation on after tax operating earnings		(29)	61	(31)	110
Gain (loss) on change in fair value of derivative, interest rate component, operating		19	20	60	64
Aflac Japan
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings	[2]	748	827	2,308	2,436
Hedge costs		60	54	168	123
Aflac U.S.
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings		316	323	956	946
Other business segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings		5	4	9	12
Total Business Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings		1,069	1,154	3,273	3,394
Interest expense, noninsurance operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings		(30)	(31)	(89)	(90)
Corporate and eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pretax operating earnings		$ (25)	$ (31)	$ (70)	$ (91)
[1]	Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine-month periods ended September 30, 2017, and 2016, respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from net investment income when analyzing segment operations to conform to current year reporting.
[2]	Amortized hedge costs related to hedging U.S. dollar-denominated investments held in Aflac Japan were $60 and $54 for the three-month periods and $168 and $123 for the nine-month periods ended September 30, 2017, and 2016, respectively, and have been reclassified from realized investment gains (losses) and reported as a deduction from pretax operating earnings when analyzing segment operations to conform to current year reporting.
[3]	Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine-month periods ended September 30, 2017, and 2016, respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations
[4]	Excluding a gain of $19 and $20 for the three-month periods and $60 and $64 for the nine-month periods ended September 30, 2017, and 2016, respectively, related to the interest rate component of the change in fair value of foreign currency swaps on notes payable which is classified as an operating gain when analyzing segment operations
[5]	Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total earnings before income taxes.
[6]	Prior year foreign currency transaction gains and losses have been reclassified from other non-operating income (loss) to realized investment gains (losses) to conform to current-year reporting classifications. These reclassifications had no impact on total revenues

BUSINESS SEGMENT INFORMATION 35

BUSINESS SEGMENT INFORMATION - Operations by Segment - Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 136,083	$ 129,819
Aflac Japan
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	113,625	107,858
Aflac U.S.
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	20,348	19,453
Other business segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	513	270
Total Business Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	134,486	127,581
Corporate and eliminations
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 1,597	$ 2,238

INVESTMENTS - Available-For-Sal

INVESTMENTS - Available-For-Sale Investments in Debt Securities, Perpetual Securities and Equity Securities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 74,604	$ 69,072
Gross Unrealized Gains	9,677	8,722
Gross Unrealized Losses	1,075	1,092
Fair Value	83,206	76,702
Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	72,244	66,363
Gross Unrealized Gains	9,206	8,432
Gross Unrealized Losses	1,035	1,035
Fair Value	80,415	73,760
Perpetual securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,549	1,506
Gross Unrealized Gains	346	176
Gross Unrealized Losses	32	49
Fair Value	1,863	1,633
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	811	1,203
Gross Unrealized Gains	125	114
Gross Unrealized Losses	8	8
Fair Value	928	1,309
Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	37,779	32,459
Gross Unrealized Gains	5,151	4,951
Gross Unrealized Losses	532	261
Fair Value	42,398	37,149
Yen-denominated | Equity securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	555	624
Gross Unrealized Gains	95	83
Gross Unrealized Losses	2	2
Fair Value	648	705
Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	34,465	33,904
Gross Unrealized Gains	4,055	3,481
Gross Unrealized Losses	503	774
Fair Value	38,017	36,611
Dollar-denominated | Equity securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	256	579
Gross Unrealized Gains	30	31
Gross Unrealized Losses	6	6
Fair Value	280	604
Japan government and agencies | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	27,027	22,857
Gross Unrealized Gains	3,272	3,359
Gross Unrealized Losses	423	160
Fair Value	29,876	26,056
Municipalities | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	1,292	1,295
Municipalities | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	315	246
Gross Unrealized Gains	26	29
Gross Unrealized Losses	15	8
Fair Value	326	267
Municipalities | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	818	894
Gross Unrealized Gains	148	142
Gross Unrealized Losses	0	8
Fair Value	966	1,028
Mortgage- and asset-backed securities | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	456	1,337
Mortgage- and asset-backed securities | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	248	1,096
Gross Unrealized Gains	29	33
Gross Unrealized Losses	0	8
Fair Value	277	1,121
Mortgage- and asset-backed securities | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	166	196
Gross Unrealized Gains	13	20
Gross Unrealized Losses	0	0
Fair Value	179	216
Public utilities | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	8,015	7,683
Public utilities | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,643	1,533
Gross Unrealized Gains	369	318
Gross Unrealized Losses	7	3
Fair Value	2,005	1,848
Public utilities | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	5,231	5,205
Gross Unrealized Gains	813	690
Gross Unrealized Losses	34	60
Fair Value	6,010	5,835
Sovereign and supranational | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	2,029	1,469
Sovereign and supranational | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,428	862
Gross Unrealized Gains	190	186
Gross Unrealized Losses	3	5
Fair Value	1,615	1,043
Sovereign and supranational | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	325	335
Gross Unrealized Gains	89	91
Gross Unrealized Losses	0	0
Fair Value	414	426
Banks/financial institutions | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	7,010	6,063
Banks/financial institutions | Perpetual securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	1,627	1,420
Banks/financial institutions | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,307	2,673
Gross Unrealized Gains	494	403
Gross Unrealized Losses	59	74
Fair Value	3,742	3,002
Banks/financial institutions | Yen-denominated | Perpetual securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	1,308	1,266
Gross Unrealized Gains	277	128
Gross Unrealized Losses	32	49
Fair Value	1,553	1,345
Banks/financial institutions | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	2,683	2,570
Gross Unrealized Gains	592	507
Gross Unrealized Losses	7	16
Fair Value	3,268	3,061
Banks/financial institutions | Dollar-denominated | Perpetual securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	46	51
Gross Unrealized Gains	28	24
Gross Unrealized Losses	0	0
Fair Value	74	75
Other corporate | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	31,575	29,699
Other corporate | Perpetual securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	236	213
Other corporate | Yen-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,811	3,192
Gross Unrealized Gains	771	623
Gross Unrealized Losses	25	3
Fair Value	4,557	3,812
Other corporate | Yen-denominated | Perpetual securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	195	189
Gross Unrealized Gains	41	24
Gross Unrealized Losses	0	0
Fair Value	236	213
Other corporate | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	25,092	24,556
Gross Unrealized Gains	2,388	2,021
Gross Unrealized Losses	462	690
Fair Value	27,018	25,887
U.S. government and agencies | Dollar-denominated | Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	150	148
Gross Unrealized Gains	12	10
Gross Unrealized Losses	0	0
Fair Value	$ 162	$ 158

INVESTMENTS - Held-to-Maturity

INVESTMENTS - Held-to-Maturity Investments in Debt Securities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	$ 31,998	$ 33,350
Gross Unrealized Gains	6,619	6,735
Gross Unrealized Losses	18	64
Fair Value	38,599	40,021
Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Fair Value	38,599	40,021
Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	31,998	33,350
Gross Unrealized Gains	6,619	6,735
Gross Unrealized Losses	18	64
Fair Value	38,599	40,021
Japan government and agencies | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	21,385	20,702
Gross Unrealized Gains	5,070	5,338
Gross Unrealized Losses	0	0
Fair Value	26,455	26,040
Municipalities | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	359	350
Fair Value	463	457
Municipalities | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	359	350
Gross Unrealized Gains	104	107
Gross Unrealized Losses	0	0
Fair Value	463	457
Mortgage- and asset-backed securities | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	27	30
Fair Value	29	32
Mortgage- and asset-backed securities | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	27	30
Gross Unrealized Gains	2	2
Gross Unrealized Losses	0	0
Fair Value	29	32
Public utilities | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,308	3,201
Fair Value	3,734	3,536
Public utilities | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	3,308	3,201
Gross Unrealized Gains	426	358
Gross Unrealized Losses	0	23
Fair Value	3,734	3,536
Sovereign and supranational | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	1,527	2,602
Fair Value	1,846	2,877
Sovereign and supranational | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	1,527	2,602
Gross Unrealized Gains	319	283
Gross Unrealized Losses	0	8
Fair Value	1,846	2,877
Banks/financial institutions | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,700	3,731
Fair Value	2,887	3,900
Banks/financial institutions | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,700	3,731
Gross Unrealized Gains	205	195
Gross Unrealized Losses	18	26
Fair Value	2,887	3,900
Other corporate | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,692	2,734
Fair Value	3,185	3,179
Other corporate | Yen-denominated | Fixed maturities
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, fixed maturities, amortized cost	2,692	2,734
Gross Unrealized Gains	493	452
Gross Unrealized Losses	0	7
Fair Value	$ 3,185	$ 3,179

INVESTMENTS - Additional Inform

INVESTMENTS - Additional Information (Detail) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017USD ($)investment	Jun. 30, 2017USD ($)investment	Mar. 31, 2017investment	Sep. 30, 2016investment	Dec. 31, 2016USD ($)
Schedule of Investments [Line Items]
Held to maturity securities transferred to available for sale securities, number of investments | investment	0	3	0	0
Middle Market Loan Program Unfunded Amount	$ 133				$ 91
Middle market loan commitments	$ 530
Percentage that the lending policy requires that the fair value of the securities and/or unrestricted cash received as collateral be of the fair value of the loaned securities	102.00%
Allowance for loan losses for commercial mortgage loans and middle market loans	$ 8				$ 3
Commercial mortgage loan commitments	103
Held-to-maturity Securities, Transferred Security, at Carrying Value		$ 773
Held-to-maturity Securities, Transferred Security, Unrealized Gain (Loss)		$ 47
Limited partnerships investment commitments	365
Parent Company and Other Business Segments
Schedule of Investments [Line Items]
Securities available for sale, fixed maturities, amortized cost	681
Securities available for sale, fixed maturities, fair value	$ 700

INVESTMENTS - Contractual Matur

INVESTMENTS - Contractual Maturities of Investments in Fixed Maturities (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Held to maturity:
Total fixed maturities held to maturity, amortized cost	$ 31,998	$ 33,350
Held to maturity:
Total fixed maturities held to maturity, fair value	38,599	$ 40,021
Aflac Japan
Available for sale:
Due in one year or less	175
Due after one year through five years	5,734
Due after five years through 10 years	9,078
Due after 10 years	43,860
Mortgage- and asset-backed securities	290
Total fixed maturities available for sale, amortized cost	59,137
Held to maturity:
Due in one year or less	488
Due after one year through five years	923
Due after five years through 10 years	1,638
Due after 10 years	28,922
Mortgage- and asset-backed securities	27
Total fixed maturities held to maturity, amortized cost	31,998
Available for sale:
Due in one year or less	181
Due after one year through five years	6,029
Due after five years through 10 years	9,668
Due after 10 years	49,502
Mortgage- and asset-backed securities	330
Total fixed maturities available for sale, fair value	65,710
Held to maturity:
Due in one year or less	497
Due after one year through five years	970
Due after five years through 10 years	1,810
Due after 10 years	35,293
Mortgage- and asset-backed securities	29
Total fixed maturities held to maturity, fair value	38,599
Aflac U.S.
Available for sale:
Due in one year or less	53
Due after one year through five years	637
Due after five years through 10 years	3,253
Due after 10 years	8,443
Mortgage- and asset-backed securities	40
Total fixed maturities available for sale, amortized cost	12,426
Held to maturity:
Due in one year or less	0
Due after one year through five years	0
Due after five years through 10 years	0
Due after 10 years	0
Mortgage- and asset-backed securities	0
Total fixed maturities held to maturity, amortized cost	0
Available for sale:
Due in one year or less	54
Due after one year through five years	682
Due after five years through 10 years	3,529
Due after 10 years	9,698
Mortgage- and asset-backed securities	42
Total fixed maturities available for sale, fair value	14,005
Held to maturity:
Due in one year or less	0
Due after one year through five years	0
Due after five years through 10 years	0
Due after 10 years	0
Mortgage- and asset-backed securities	0
Total fixed maturities held to maturity, fair value	$ 0

INVESTMENTS - Economic Maturiti

INVESTMENTS - Economic Maturities of Investments in Perpetual Securities (Detail) $ in Millions	Sep. 30, 2017USD ($)
Aflac Japan
Investments Classified by Economic Maturity Date [Line Items]
Due in one year or less	$ 84
Due after one year through five years	194
Due after 10 years	1,232
Total perpetual securities available for sale, amortized cost	1,510
Due in one year or less	85
Due after one year through five years	236
Due after 10 years	1,482
Total perpetual securities available for sale, fair value	1,803
Aflac U.S.
Investments Classified by Economic Maturity Date [Line Items]
Due in one year or less	0
Due after one year through five years	0
Due after 10 years	39
Total perpetual securities available for sale, amortized cost	39
Due in one year or less	0
Due after one year through five years	0
Due after 10 years	60
Total perpetual securities available for sale, fair value	$ 60

INVESTMENTS - Investment Exposu

INVESTMENTS - Investment Exposures Individually Exceeded 10% of Shareholders' Equity (Details) - Japan National Government - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Summary of Investment Holdings [Line Items]
Credit Rating	[1]	A	A
Amortized Cost	[1]	$ 47,637	$ 42,931
Fair Value	[1]	$ 55,444	$ 51,345
[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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment losses realized	$ (8)	$ (23)	$ (27)	$ (71)
Derivative gains (losses)	(40)	(107)	(143)	(278)
Foreign currency gains (losses)	17	(20)	(56)	(109)
Total realized investment gains (losses)	30	(164)	(166)	(358)
Derivatives and other
Gain (Loss) on Investments [Line Items]
Total realized investment gains (losses)	(23)	(127)	(199)	(387)
Fixed maturities
Gain (Loss) on Investments [Line Items]
Total realized investment gains (losses)	14	(20)	(44)	37
Perpetual securities
Gain (Loss) on Investments [Line Items]
Total realized investment gains (losses)	0	0	4	38
Equity securities
Gain (Loss) on Investments [Line Items]
Gross gains from sales	54	5	102	10
Gross losses from sales	(9)	0	(11)	(10)
Other-than-temporary impairment losses realized	(6)	(22)	(18)	(46)
Total realized investment gains (losses)	39	(17)	73	(46)
Available-for-sale securities | Fixed maturities
Gain (Loss) on Investments [Line Items]
Gross gains from sales	10	2	27	10
Gross losses from sales	(8)	(22)	(38)	(38)
Net gains (losses) from redemptions	14	1	(24)	88
Other-than-temporary impairment losses realized	(2)	(1)	(9)	(23)
Available-for-sale securities | Perpetual securities
Gain (Loss) on Investments [Line Items]
Net gains (losses) from redemptions	0	0	4	40
Other-than-temporary impairment losses realized	$ 0	$ 0	$ 0	$ (2)

INVESTMENTS - Net Effect on Sha

INVESTMENTS - Net Effect on Shareholders' Equity of Unrealized Gains and Losses from Investment Securities (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Investments [Abstract]
Unrealized Gains (Losses) on Available-for-sale Securities	$ 8,602	$ 7,630
Deferred income taxes	(3,165)	(2,825)
Shareholders' equity, unrealized gains (losses) on investment securities	$ 5,437	$ 4,805

INVESTMENTS - Fair Value and Gr

INVESTMENTS - Fair Value and Gross Unrealized Losses for Securities That Have Been in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	$ 18,466	$ 20,275
Total Unrealized Losses	1,093	1,156
Less than 12 months Fair Value	11,031	14,743
Less than 12 months Unrealized Losses	529	621
12 months or longer Fair Value	7,435	5,532
12 months or longer Unrealized Losses	564	535
Fixed maturities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	17,996	19,536
Total Unrealized Losses	1,053	1,099
Less than 12 months Fair Value	10,914	14,398
Less than 12 months Unrealized Losses	523	612
12 months or longer Fair Value	7,082	5,138
12 months or longer Unrealized Losses	530	487
Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	340	479
Total Unrealized Losses	32	49
Less than 12 months Fair Value	0	85
Less than 12 months Unrealized Losses	0	1
12 months or longer Fair Value	340	394
12 months or longer Unrealized Losses	32	48
Equity securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	130	260
Total Unrealized Losses	8	8
Less than 12 months Fair Value	117	260
Less than 12 months Unrealized Losses	6	8
12 months or longer Fair Value	13	0
12 months or longer Unrealized Losses	2	0
Yen-denominated | Fixed maturities | Japan government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	6,404	3,958
Total Unrealized Losses	423	160
Less than 12 months Fair Value	6,208	3,958
Less than 12 months Unrealized Losses	399	160
12 months or longer Fair Value	196	0
12 months or longer Unrealized Losses	24	0
Yen-denominated | Fixed maturities | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	152	105
Total Unrealized Losses	15	8
Less than 12 months Fair Value	62	105
Less than 12 months Unrealized Losses	3	8
12 months or longer Fair Value	90	0
12 months or longer Unrealized Losses	12	0
Yen-denominated | Fixed maturities | Mortgage- and asset-backed securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		713
Total Unrealized Losses		8
Less than 12 months Fair Value		713
Less than 12 months Unrealized Losses		8
12 months or longer Fair Value		0
12 months or longer Unrealized Losses		0
Yen-denominated | Fixed maturities | Public utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	95	635
Total Unrealized Losses	7	26
Less than 12 months Fair Value	69	347
Less than 12 months Unrealized Losses	6	14
12 months or longer Fair Value	26	288
12 months or longer Unrealized Losses	1	12
Yen-denominated | Fixed maturities | Sovereign and supranational
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	352	244
Total Unrealized Losses	3	13
Less than 12 months Fair Value	352	38
Less than 12 months Unrealized Losses	3	5
12 months or longer Fair Value	0	206
12 months or longer Unrealized Losses	0	8
Yen-denominated | Fixed maturities | Banks/financial institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,616	1,521
Total Unrealized Losses	77	100
Less than 12 months Fair Value	637	636
Less than 12 months Unrealized Losses	29	19
12 months or longer Fair Value	979	885
12 months or longer Unrealized Losses	48	81
Yen-denominated | Fixed maturities | Other corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	424	321
Total Unrealized Losses	25	10
Less than 12 months Fair Value	386	321
Less than 12 months Unrealized Losses	24	10
12 months or longer Fair Value	38	0
12 months or longer Unrealized Losses	1	0
Yen-denominated | Perpetual securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	340	479
Total Unrealized Losses	32	49
Less than 12 months Fair Value	0	85
Less than 12 months Unrealized Losses	0	1
12 months or longer Fair Value	340	394
12 months or longer Unrealized Losses	32	48
Yen-denominated | Equity securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	72	49
Total Unrealized Losses	2	2
Less than 12 months Fair Value	67	49
Less than 12 months Unrealized Losses	1	2
12 months or longer Fair Value	5	0
12 months or longer Unrealized Losses	1	0
Dollar-denominated | Fixed maturities | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value		44
Total Unrealized Losses		8
Less than 12 months Fair Value		0
Less than 12 months Unrealized Losses		0
12 months or longer Fair Value		44
12 months or longer Unrealized Losses		8
Dollar-denominated | Fixed maturities | Public utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	879	1,265
Total Unrealized Losses	34	60
Less than 12 months Fair Value	252	790
Less than 12 months Unrealized Losses	4	32
12 months or longer Fair Value	627	475
12 months or longer Unrealized Losses	30	28
Dollar-denominated | Fixed maturities | Banks/financial institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	188	268
Total Unrealized Losses	7	16
Less than 12 months Fair Value	145	238
Less than 12 months Unrealized Losses	3	10
12 months or longer Fair Value	43	30
12 months or longer Unrealized Losses	4	6
Dollar-denominated | Fixed maturities | Other corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	7,886	10,462
Total Unrealized Losses	462	690
Less than 12 months Fair Value	2,803	7,252
Less than 12 months Unrealized Losses	52	346
12 months or longer Fair Value	5,083	3,210
12 months or longer Unrealized Losses	410	344
Dollar-denominated | Equity securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	58	211
Total Unrealized Losses	6	6
Less than 12 months Fair Value	50	211
Less than 12 months Unrealized Losses	5	6
12 months or longer Fair Value	8	0
12 months or longer Unrealized Losses	$ 1	$ 0

INVESTMENTS - Other Investments

INVESTMENTS - Other Investments (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Investment Holdings [Line Items]
Other Investments	[1]	$ 2,358	$ 1,450
Commercial mortgage loans
Investment Holdings [Line Items]
Other Investments		1,199	855
Middle market loans
Investment Holdings [Line Items]
Other Investments		798	319
Policy loans
Investment Holdings [Line Items]
Other Investments		207	184
Short-term investments
Investment Holdings [Line Items]
Other Investments		57	89
Other investments
Investment Holdings [Line Items]
Other Investments		$ 97	$ 3
[1]	Includes $1,500 in 2017 and $819 in 2016 of loan receivables and limited partnerships from consolidated variable interest entities

INVESTMENTS - Investments in Co

INVESTMENTS - Investments in Consolidated Variable Interest Entities (Detail) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Other Investments, amortized cost	[1]	$ 2,358	$ 1,450
Asset derivatives		479	1,207
Assets, fair value		88,669	83,044
Liability derivatives		974	1,998
Liabilities		114,106	109,337
Liabilities, fair value disclosure		974	1,998
Variable Interest Entity, Consolidated
Variable Interest Entity [Line Items]
Securities available for sale, fixed maturities, amortized cost		4,274	4,168
Securities available for sale, fixed maturities, fair value		5,224	4,982
Securities available for sale, perpetual securities, amortized cost		239	237
Securities available for sale, perpetual securities, fair value		211	208
Available-for-sale equity securities, amortized cost basis		595	972
Available-for-sale securities, equity securities		690	1,044
Other Investments, amortized cost	[2]	1,500	819
Other investments, fair value	[2]	1,491	789
Asset derivative, amortized cost	[3]	148	127
Asset derivatives	[3]	148	127
Assets, amortized cost		6,756	6,323
Assets, fair value		7,764	7,150
Liability derivatives, amortized cost	[3]	132	146
Liability derivatives	[3]	132	146
Liabilities		132	146
Liabilities, fair value disclosure		$ 132	$ 146
[1]	Includes $1,500 in 2017 and $819 in 2016 of loan receivables and limited partnerships from consolidated variable interest entities
[2]	Consists of CMLs, MMLs, and alternative investments in limited partnerships
[3]	Consists entirely of derivatives

INVESTMENTS - Investments in Va

INVESTMENTS - Investments in Variable Interest Entities Not Consolidated (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Securities held to maturity, fixed maturities, amortized cost		$ 31,998	$ 33,350
Securities held to maturity, fixed maturities, fair value		38,599	40,021
Other Investments	[1]	2,358	1,450
Assets, fair value		88,669	83,044
Variable Interest Entity, Not Consolidated
Variable Interest Entity [Line Items]
Securities available for sale, fixed maturities, amortized cost		4,766	4,729
Securities available for sale, fixed maturities, fair value		5,439	5,261
Securities available for sale, perpetual securities, amortized cost		177	172
Securities available for sale, perpetual securities, fair value		220	200
Securities held to maturity, fixed maturities, amortized cost		2,645	2,563
Securities held to maturity, fixed maturities, fair value		3,047	2,948
Other Investments		50	1
Other investments, fair value		50	1
Assets, amortized cost		7,638	7,465
Assets, fair value		$ 8,756	$ 8,410
[1]	Includes $1,500 in 2017 and $819 in 2016 of loan receivables and limited partnerships from consolidated variable interest entities

INVESTMENTS - Securities Lendin

INVESTMENTS - Securities Lending Transactions Accounted for as Secured Borrowings (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
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		$ 522	$ 526
Gross amount of recognized liabilities for securities lending		522	526
Amounts related to agreements not included in offsetting disclosure in Note 4		0	0
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		37	62
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		37	34
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		434	430
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		14
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]	522	526
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]	37	62
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]	37	34
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]	434	430
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]	14
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		0	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
[1]	These securities are pledged as collateral under the Company's U.S. securities lending program and can be called at its discretion; therefore, they are classified as Overnight and Continuous.

DERIVATIVE INSTRUMENTS - Additi

DERIVATIVE INSTRUMENTS - Additional Information (Detail) $ in Millions, ¥ in Billions	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)yrcounterparties	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)yrcounterparties	Sep. 30, 2016USD ($)	Sep. 30, 2017JPY (¥)yrcounterparties	Dec. 31, 2016USD ($)
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedging activity weighted-average period (in years) | yr	9		9		9
Notional Amount of Derivatives	$ 28,250		$ 28,250			$ 43,927
Number of counterparties | counterparties	15		15		15
Number of counterparties that comprise majority of aggregate notional amount of swaps | counterparties	5		5		5
Percentage of notional amount of swaps from certain number of counterparties	67.00%		67.00%		67.00%
Derivative, Net Liability Position, Aggregate Fair Value	$ 623		$ 623			1,200
Additional Collateral, Aggregate Fair Value	5		5
Net investment hedge
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	612		612			1,052
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	$ 0	0	$ 0
Net investment hedge | Foreign currency forwards
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	48		48			209
Cash flow hedges
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	75		75			$ 75
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		$ 1		$ 1
2.40% senior notes due March 2020
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	550		550
4.00% senior notes due February 2022
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	350		350
3.625% senior notes due June 2023
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	700		700
3.625% senior notes due November 2024
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	750		750
3.25% senior notes due March 2025
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	450		450
5.50% subordinated notes due September 2052
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Debt instrument, principal amount	500		500
September 2017 Profit Repatriation | Foreign currency forwards and options
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives | ¥					¥ 21.9
July 2017 profit repatriation | Foreign currency forwards and options
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives | ¥					45
Future profit repatriation | Foreign currency forwards and options
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives | ¥					¥ 68.9
Loans receivable | Foreign currency forwards
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	$ 1,600		$ 1,600

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	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	$ 28,250	$ 43,927
Derivative asset, fair value, gross asset including not subject to master netting arrangement	479	1,207
Derivative liability, fair value, gross liability including not subject to master netting arrangement	(974)	(1,998)
Asset derivatives fair value	331	1,080
Liability derivatives fair value	(842)	(1,852)
Other assets
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	9,509	18,329
Asset derivatives fair value	479	1,207
Liability derivatives fair value	0	0
Other liabilities
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	18,741	25,598
Asset derivatives fair value	0	0
Liability derivatives fair value	(974)	(1,998)
Cash flow hedges
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	75	75
Asset derivatives fair value	0	0
Liability derivatives fair value	(9)	(10)
Cash flow hedges | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	75	75
Asset derivatives fair value	0	0
Liability derivatives fair value	(9)	(10)
Fair value hedges
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	14,938	15,189
Asset derivatives fair value	0	2
Liability derivatives fair value	(431)	(791)
Fair value hedges | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	9,278	10,965
Asset derivatives fair value	0	0
Liability derivatives fair value	(411)	(759)
Fair value hedges | Foreign currency options
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	5,660	4,224
Asset derivatives fair value	0	2
Liability derivatives fair value	(20)	(32)
Net investment hedge
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	612	1,052
Asset derivatives fair value	18	46
Liability derivatives fair value	(4)	(19)
Net investment hedge | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	48	209
Asset derivatives fair value	1	5
Liability derivatives fair value	0	(2)
Net investment hedge | Foreign currency options
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	564	843
Asset derivatives fair value	17	41
Liability derivatives fair value	(4)	(17)
Non-qualifying strategies
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	12,625	27,611
Asset derivatives fair value	461	1,159
Liability derivatives fair value	(530)	(1,178)
Non-qualifying strategies | Foreign currency swaps
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	5,387	6,266
Asset derivatives fair value	301	490
Liability derivatives fair value	(187)	(220)
Non-qualifying strategies | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	7,124	21,218
Asset derivatives fair value	159	667
Liability derivatives fair value	(343)	(956)
Non-qualifying strategies | Foreign currency options
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	25	41
Asset derivatives fair value	0	0
Liability derivatives fair value	0	(2)
Non-qualifying strategies | Credit default swaps
Derivatives, Fair Value [Line Items]
Net Derivatives Notional Amount	89	86
Asset derivatives fair value	1	2
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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fixed-maturity securities and equity securities | Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives	$ (114)	$ 90	$ 193	$ 2,103
Gains (losses) on derivatives excluded from effectiveness testing	(53)	(186)	(151)	(278)
Gains (losses) on derivatives included in effectiveness testing	(61)	276	344	2,381
Gains (losses) recognized for hedged items	61	(288)	(326)	(2,406)
Ineffectiveness recognized for fair value hedge	0	(12)	18	(25)
Fixed maturities | Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives	(14)	(4)	3	2
Gains (losses) on derivatives excluded from effectiveness testing	(14)	(4)	(8)	2
Gains (losses) on derivatives included in effectiveness testing	0	0	11	0
Gains (losses) recognized for hedged items	0	0	(10)	0
Ineffectiveness recognized for fair value hedge	$ 0	$ 0	$ 1	$ 0

DERIVATIVE INSTRUMENTS - Deriva

DERIVATIVE INSTRUMENTS - Derivatives and Hedging Instruments Gain (Loss) Summary (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized foreign currency translation gains (losses) during period		$ (58)	$ 195	$ 325	$ 1,783
Derivative gains (losses)		(40)	(107)	(143)	(278)
Derivative and non-derivative hedging instruments gain loss recognized in other comprehensive income effective portion before tax	[1]	3	1	(34)	(189)
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)		0	0	0	1
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	(1)	0	0	11
Cash flow hedges | Foreign currency swaps
Derivative Instruments, Gain (Loss) [Line Items]
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)		0	0	0	1
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	(1)	0	0	11
Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)		(67)	(202)	(140)	(301)
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	0	0	0	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)	[2]	(53)	(198)	(133)	(303)
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1],[2]	0	0	0	0
Fair value hedges | Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)	[2]	(14)	(4)	(7)	2
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1],[2]	0	0	0	0
Net investment hedge
Derivative Instruments, Gain (Loss) [Line Items]
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)		0	0	0	0
Unrealized foreign currency translation gains (losses) during period	[1]	4	1	(34)	(200)
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	0	0
Unrealized foreign currency translation gains (losses) during period	[1]	5	(2)	(13)	(39)
Net investment hedge | Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Net Realized Investment Gains (Losses) Recognized in Income on Derivative (Ineffective Portion)		0	0	0	0
Unrealized foreign currency translation gains (losses) during period	[1]	4	(28)	(24)	(161)
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	0	0
Unrealized foreign currency translation gains (losses) during period	[1]	(5)	31	3	0
Non-qualifying strategies
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net		27	95	(3)	22
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	0	0	0	0
Non-qualifying strategies | Foreign currency swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net		17	(51)	43	(145)
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	0	0	0	0
Non-qualifying strategies | Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net		10	144	(46)	165
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	0	0	0	0
Non-qualifying strategies | Credit default swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net		0	2	0	2
Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	[1]	$ 0	$ 0	$ 0	$ 0
[1]	Cash flow hedge items 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).
[2]	Impact shown net of effect of hedged items (see Fair Value Hedges section of this Note 4 for further detail)

DERIVATIVE INSTRUMENTS - Fair V

DERIVATIVE INSTRUMENTS - Fair Value and Notional Amounts of Derivatives With Counterparty Credit Risk (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	$ 28,250	$ 43,927
Asset Derivatives Fair Value	479	1,207
Liability Derivatives Fair Value	(974)	(1,998)
AA
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	5,553	6,844
Asset Derivatives Fair Value	90	247
Liability Derivatives Fair Value	(189)	(308)
A
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	22,257	36,019
Asset Derivatives Fair Value	381	900
Liability Derivatives Fair Value	(718)	(1,621)
BBB
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivatives	440	1,064
Asset Derivatives Fair Value	8	60
Liability Derivatives Fair Value	$ (67)	$ (69)

DERIVATIVE INSTRUMENTS - Offset

DERIVATIVE INSTRUMENTS - Offsetting of Financial Assets and Derivative Assets (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	$ 331	$ 1,080
Gross amount of liabilities offset in balance sheet	0	0
Net amount of derivative assets presented in the balance sheet	331	1,080
Financial instruments, amount not offset	(219)	(698)
Derivative, collateral, obligation to return securities	0	0
Derivative, collateral, obligation to return cash	(112)	(382)
Derivative asset, fair value, amount offset against collateral, subject to master netting agreement	0	0
Derivative asset, not subject to master netting arrangement	148	127
Derivative asset, fair value, amount offset against collateral, not subject to master netting agreement	148	127
Derivative asset, fair value, gross asset including not subject to master netting arrangement	479	1,207
Net amount of derivative assets presented in balance sheet	479	1,207
Derivative asset, fair value, amount offset against collateral	148	127
Gross amounts of recognized financial instruments	988	1,720
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	988	1,720
Carrying value of financial instruments not offset in balance sheet	(219)	(698)
Securities collateral, not offset in balance sheet	0	0
Cash collateral, not offset in balance sheet	(621)	(895)
Financial instruments, amount offset against collateral	148	127
Securities lending and similar arrangements
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	509	513
Gross amounts offset in balance sheet	0	0
Net amounts of assets presented in balance sheet	509	513
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	(509)	(513)
Financial instruments, amount offset against collateral	$ 0	$ 0

DERIVATIVE INSTRUMENTS - Offs55

DERIVATIVE INSTRUMENTS - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	$ (842)	$ (1,852)
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	(842)	(1,852)
Financial instruments, amount not offset	219	698
Derivative, collateral, right to reclaim securities	611	1,130
Derivative, collateral, right to reclaim cash	7	21
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	(5)	(3)
Derivative liability, not subject to master netting arrangement	(132)	(146)
Derivative liability, fair value, amount offset against collateral, not subject to master netting agreement	(132)	(146)
Derivative liability, fair value, gross liability including not subject to master netting arrangement	(974)	(1,998)
Net amount of derivative liabilities presented in balance sheet	(974)	(1,998)
Derivative liability, fair value, amount offset against collateral	(137)	(149)
Gross Amounts of Recognized Financial Instruments, Offsetting Liabilities	(1,496)	(2,524)
Gross Amounts Offset in Statement of Financial Position, Offsetting Liabilities	0	0
Net Amounts of Financial Instruments Presented in Balance Sheet, Offsetting Liabilities	(1,496)	(2,524)
Carrying value of financial instruments, liabilities not offset in balance sheet	728	1,211
Securities Collateral, Liabilities Not Offset in Balance Sheet	611	1,130
Cash Collateral, Liabilities Not Offset in Balance Sheet	7	21
Financial instruments, amount of liabilities offset against collateral	(150)	(162)
Securities lending and similar arrangements
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Financial Instruments, Offsetting Liabilities	(522)	(526)
Gross Amounts Offset in Statement of Financial Position, Offsetting Liabilities	0	0
Net Amounts of Financial Instruments Presented in Balance Sheet, Offsetting Liabilities	(522)	(526)
Carrying value of financial instruments, liabilities not offset in balance sheet	509	513
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	$ (13)	$ (13)

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	Sep. 30, 2017	Dec. 31, 2016
Assets:
Available-for-sale Securities	$ 83,206	$ 76,702
Asset derivatives	479	1,207
Other Investments	57	276
Cash and cash equivalents	4,927	4,859
Total assets	88,669	83,044
Liabilities:
Liability derivatives	974	1,998
Total liabilities	974	1,998
Foreign currency swaps
Assets:
Asset derivatives	301	490
Liabilities:
Liability derivatives	196	230
Foreign currency forwards
Assets:
Asset derivatives	160	672
Liabilities:
Liability derivatives	754	1,717
Foreign currency options
Assets:
Asset derivatives	17	43
Liabilities:
Liability derivatives	24	51
Credit default swaps
Assets:
Asset derivatives	1	2
Fixed maturities
Assets:
Available-for-sale Securities	80,415	73,760
Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	30,038	26,214
Fixed maturities | Municipalities
Assets:
Available-for-sale Securities	1,292	1,295
Fixed maturities | Mortgage- and asset-backed securities
Assets:
Available-for-sale Securities	456	1,337
Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	8,015	7,683
Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	2,029	1,469
Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	7,010	6,063
Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	31,575	29,699
Perpetual securities
Assets:
Available-for-sale Securities	1,863	1,633
Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	1,627	1,420
Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	236	213
Equity securities
Assets:
Available-for-sale Securities	928	1,309
Level 1
Assets:
Available-for-sale Securities	29,972	26,687
Asset derivatives	0	0
Other Investments	57	276
Cash and cash equivalents	4,927	4,859
Total assets	34,956	31,822
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	0
Liabilities:
Liability derivatives	0	0
Level 1 | Credit default swaps
Assets:
Asset derivatives	0	0
Level 1 | Fixed maturities
Assets:
Available-for-sale Securities	29,067	25,387
Level 1 | Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	29,067	25,387
Level 1 | Fixed maturities | Municipalities
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed maturities | Mortgage- and asset-backed securities
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	0	0
Level 1 | Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	0	0
Level 1 | Perpetual securities
Assets:
Available-for-sale Securities	0	0
Level 1 | Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	0	0
Level 1 | Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	0	0
Level 1 | Equity securities
Assets:
Available-for-sale Securities	905	1,300
Level 2
Assets:
Available-for-sale Securities	52,834	49,773
Asset derivatives	331	1,080
Other Investments	0	0
Cash and cash equivalents	0	0
Total assets	53,165	50,853
Liabilities:
Total liabilities	842	1,852
Level 2 | Foreign currency swaps
Assets:
Asset derivatives	154	365
Liabilities:
Liability derivatives	64	84
Level 2 | Foreign currency forwards
Assets:
Asset derivatives	160	672
Liabilities:
Liability derivatives	754	1,717
Level 2 | Foreign currency options
Assets:
Asset derivatives	17	43
Liabilities:
Liability derivatives	24	51
Level 2 | Credit default swaps
Assets:
Asset derivatives	0	0
Level 2 | Fixed maturities
Assets:
Available-for-sale Securities	50,966	48,134
Level 2 | Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	971	827
Level 2 | Fixed maturities | Municipalities
Assets:
Available-for-sale Securities	1,292	1,295
Level 2 | Fixed maturities | Mortgage- and asset-backed securities
Assets:
Available-for-sale Securities	278	1,139
Level 2 | Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	7,938	7,667
Level 2 | Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	2,029	1,469
Level 2 | Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	6,985	6,038
Level 2 | Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	31,473	29,699
Level 2 | Perpetual securities
Assets:
Available-for-sale Securities	1,863	1,633
Level 2 | Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	1,627	1,420
Level 2 | Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	236	213
Level 2 | Equity securities
Assets:
Available-for-sale Securities	5	6
Level 3
Assets:
Available-for-sale Securities	400	242
Asset derivatives	148	127
Other Investments	0	0
Cash and cash equivalents	0	0
Total assets	548	369
Liabilities:
Total liabilities	132	146
Level 3 | Foreign currency swaps
Assets:
Asset derivatives	147	125
Liabilities:
Liability derivatives	132	146
Level 3 | Foreign currency forwards
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 | Foreign currency options
Assets:
Asset derivatives	0	0
Liabilities:
Liability derivatives	0	0
Level 3 | Credit default swaps
Assets:
Asset derivatives	1	2
Level 3 | Fixed maturities
Assets:
Available-for-sale Securities	382	239
Level 3 | Fixed maturities | Government and agencies
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed maturities | Municipalities
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed maturities | Mortgage- and asset-backed securities
Assets:
Available-for-sale Securities	178	198
Level 3 | Fixed maturities | Public utilities
Assets:
Available-for-sale Securities	77	16
Level 3 | Fixed maturities | Sovereign and supranational
Assets:
Available-for-sale Securities	0	0
Level 3 | Fixed maturities | Banks/financial institutions
Assets:
Available-for-sale Securities	25	25
Level 3 | Fixed maturities | Other corporate
Assets:
Available-for-sale Securities	102	0
Level 3 | Perpetual securities
Assets:
Available-for-sale Securities	0	0
Level 3 | Perpetual securities | Banks/financial institutions
Assets:
Available-for-sale Securities	0	0
Level 3 | Perpetual securities | Other corporate
Assets:
Available-for-sale Securities	0	0
Level 3 | Equity securities
Assets:
Available-for-sale Securities	$ 18	$ 3

FAIR VALUE MEASUREMENTS - Fai57

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Carried at Cost or Amortized Cost (Details) - USD ($) $ in Millions		Sep. 30, 2017		Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	[1]	$ 2,358		$ 1,450
Assets:
Securities held to maturity, fixed maturities, amortized cost		31,998		33,350
Securities held to maturity, fixed maturities, fair value		38,599		40,021
Other investments carried at amortized cost		2,011	[2]	1,174
Other investments carried at amortized cost, fair value		2,000	[2]	1,142
Total financial instruments assets not carried at fair value		34,009		34,524
Assets fair value disclosure financial instruments carried at cost		40,599		41,163
Liabilities:
Other policyholder funds		6,967		6,659
Other policyholders' funds fair value disclosure		6,849		6,540
Notes payable		5,230		5,339
Notes payable fair value disclosure		5,551		5,530
Total financial instrument liabilities not carried at fair value		12,197		11,998
Liabilities fair value disclosure financial instruments carried at cost		12,400		12,070
Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		38,599		40,021
Government and agencies | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		21,385		20,702
Securities held to maturity, fixed maturities, fair value		26,455		26,040
Municipalities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		359		350
Securities held to maturity, fixed maturities, fair value		463		457
Mortgage- and asset-backed securities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		27		30
Securities held to maturity, fixed maturities, fair value		29		32
Public utilities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		3,308		3,201
Securities held to maturity, fixed maturities, fair value		3,734		3,536
Sovereign and supranational | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		1,527		2,602
Securities held to maturity, fixed maturities, fair value		1,846		2,877
Banks/financial institutions | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		2,700		3,731
Securities held to maturity, fixed maturities, fair value		2,887		3,900
Other corporate | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, amortized cost		2,692		2,734
Securities held to maturity, fixed maturities, fair value		3,185		3,179
Policy loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments		207		184
Equity method investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments		83
Level 1
Assets:
Other investments carried at amortized cost, fair value		0	[2]	0
Assets fair value disclosure financial instruments carried at cost		26,455		26,040
Liabilities:
Other policyholders' funds fair value disclosure		0		0
Notes payable fair value disclosure		506		0
Liabilities fair value disclosure financial instruments carried at cost		506		0
Level 1 | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		26,455		26,040
Level 1 | Government and agencies | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		26,455		26,040
Level 1 | Municipalities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 1 | Mortgage- and asset-backed securities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 1 | Public utilities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 1 | Sovereign and supranational | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 1 | Banks/financial institutions | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 1 | Other corporate | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 2
Assets:
Other investments carried at amortized cost, fair value		15	[2]	0
Assets fair value disclosure financial instruments carried at cost		12,139		13,959
Liabilities:
Other policyholders' funds fair value disclosure		0		0
Notes payable fair value disclosure		4,780		0
Liabilities fair value disclosure financial instruments carried at cost		4,780		0
Level 2 | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		12,124		13,959
Level 2 | Government and agencies | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 2 | Municipalities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		463		457
Level 2 | Mortgage- and asset-backed securities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		9		10
Level 2 | Public utilities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		3,734		3,536
Level 2 | Sovereign and supranational | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		1,846		2,877
Level 2 | Banks/financial institutions | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		2,887		3,900
Level 2 | Other corporate | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		3,185		3,179
Level 3
Assets:
Other investments carried at amortized cost, fair value		1,985	[2]	1,142
Assets fair value disclosure financial instruments carried at cost		2,005		1,164
Liabilities:
Other policyholders' funds fair value disclosure		6,849		6,540
Notes payable fair value disclosure		265		5,530
Liabilities fair value disclosure financial instruments carried at cost		7,114		12,070
Level 3 | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		20		22
Level 3 | Government and agencies | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 3 | Municipalities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 3 | Mortgage- and asset-backed securities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		20		22
Level 3 | Public utilities | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 3 | Sovereign and supranational | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 3 | Banks/financial institutions | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		0		0
Level 3 | Other corporate | Fixed maturities
Assets:
Securities held to maturity, fixed maturities, fair value		$ 0		$ 0
[1]	Includes $1,500 in 2017 and $819 in 2016 of loan receivables and limited partnerships from consolidated variable interest entities
[2]	Excludes policy loans of $207 and equity method investments of $83, at carrying value

FAIR VALUE MEASUREMENTS - Fai58

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets by Pricing Source, Available-for-Sale Securities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 83,206	$ 76,702
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,972	26,687
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	52,834	49,773
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	400	242
Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	80,415	73,760
Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,067	25,387
Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	50,966	48,134
Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	382	239
Perpetual securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,863	1,633
Perpetual securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Perpetual securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,863	1,633
Perpetual securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	928	1,309
Equity securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	905	1,300
Equity securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	5	6
Equity securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	18	3
Equity securities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	910	1,306
Equity 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 Securities	905	1,300
Equity 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 Securities	5	6
Equity 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 Securities	0	0
Equity securities | Net asset value valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	18	3
Equity securities | Net asset value valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Equity securities | Net asset value valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Equity securities | Net asset value valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	18	3
Government and agencies | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	30,038	26,214
Government and agencies | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,067	25,387
Government and agencies | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	971	827
Government and agencies | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	30,038	26,214
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,067	25,387
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	971	827
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Municipalities | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,292	1,295
Municipalities | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Municipalities | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,292	1,295
Municipalities | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Municipalities | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,292	1,295
Municipalities | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Municipalities | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,292	1,295
Municipalities | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage- and asset-backed securities | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	456	1,337
Mortgage- and asset-backed securities | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage- and asset-backed securities | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	278	1,139
Mortgage- and asset-backed securities | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	178	198
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	278	1,139
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	278	1,139
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	178	198
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	178	198
Public utilities | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	8,015	7,683
Public utilities | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Public utilities | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	7,938	7,667
Public utilities | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	77	16
Public utilities | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	7,938	7,667
Public utilities | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Public utilities | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	7,938	7,667
Public utilities | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Public utilities | Fixed maturities | Discounted cash flow valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	77	16
Public utilities | Fixed maturities | Discounted cash flow valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Public utilities | Fixed maturities | Discounted cash flow valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Public utilities | Fixed maturities | Discounted cash flow valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	77	16
Sovereign and supranational | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,029	1,469
Sovereign and supranational | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Sovereign and supranational | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,029	1,469
Sovereign and supranational | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,029	1,469
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	2,029	1,469
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	7,010	6,063
Banks/financial institutions | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	6,985	6,038
Banks/financial institutions | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	25	25
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	6,985	6,038
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	6,985	6,038
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Fixed maturities | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	25	25
Banks/financial institutions | Fixed maturities | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Fixed maturities | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Fixed maturities | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	25	25
Banks/financial institutions | Perpetual securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,627	1,420
Banks/financial institutions | Perpetual securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Perpetual securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,627	1,420
Banks/financial institutions | Perpetual securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Banks/financial institutions | Perpetual securities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,627	1,420
Banks/financial institutions | Perpetual 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 Securities	0	0
Banks/financial institutions | Perpetual 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 Securities	1,627	1,420
Banks/financial institutions | Perpetual 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 Securities	0	0
Other corporate | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	31,575	29,699
Other corporate | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Other corporate | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	31,473	29,699
Other corporate | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	102	0
Other corporate | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	31,473	29,699
Other corporate | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Other corporate | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	31,473	29,699
Other corporate | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Other corporate | Fixed maturities | Discounted cash flow valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	102
Other corporate | Fixed maturities | Discounted cash flow valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0
Other corporate | Fixed maturities | Discounted cash flow valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0
Other corporate | Fixed maturities | Discounted cash flow valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	102
Other corporate | Perpetual securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	236	213
Other corporate | Perpetual securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Other corporate | Perpetual securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	236	213
Other corporate | Perpetual securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Other corporate | Perpetual securities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	236	213
Other corporate | Perpetual 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 Securities	0	0
Other corporate | Perpetual 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 Securities	236	213
Other corporate | Perpetual 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 Securities	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Fai59

FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets by Pricing Source, Held-to-Maturity Securities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	$ 38,599	$ 40,021
Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	38,599	40,021
Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	26,455	26,040
Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	12,124	13,959
Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	20	22
Government and agencies | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	26,455	26,040
Government and agencies | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	26,455	26,040
Government and agencies | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Government and agencies | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	26,455	26,040
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	26,455	26,040
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Government and agencies | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Municipalities | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	463	457
Municipalities | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Municipalities | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	463	457
Municipalities | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Municipalities | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	463	457
Municipalities | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Municipalities | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	463	457
Municipalities | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Mortgage- and asset-backed securities | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	29	32
Mortgage- and asset-backed securities | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Mortgage- and asset-backed securities | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	9	10
Mortgage- and asset-backed securities | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	20	22
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	9	10
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	9	10
Mortgage- and asset-backed securities | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	20	22
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	20	22
Public utilities | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,734	3,536
Public utilities | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Public utilities | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,734	3,536
Public utilities | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Public utilities | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,734	3,536
Public utilities | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Public utilities | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,734	3,536
Public utilities | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Sovereign and supranational | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	1,846	2,877
Sovereign and supranational | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Sovereign and supranational | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	1,846	2,877
Sovereign and supranational | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	1,846	2,877
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	1,846	2,877
Sovereign and supranational | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Banks/financial institutions | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	2,887	3,900
Banks/financial institutions | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Banks/financial institutions | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	2,887	3,900
Banks/financial institutions | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	2,887	3,900
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	2,887	3,900
Banks/financial institutions | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Other corporate | Fixed maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,185	3,179
Other corporate | Fixed maturities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Other corporate | Fixed maturities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,185	3,179
Other corporate | Fixed maturities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Other corporate | Fixed maturities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,185	3,179
Other corporate | Fixed maturities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	0	0
Other corporate | Fixed maturities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	3,185	3,179
Other corporate | Fixed maturities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities held to maturity, fixed maturities, fair value	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Chang

FAIR VALUE MEASUREMENTS - Changes in Available-For-Sale Investments and Derivatives Classified as Level 3 (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		$ 366	$ 341	$ 223	$ 58
Realized investment gains (losses) included in earnings		7	(16)	35	252
Unrealized gains (losses) included in other comprehensive income (loss)		(1)	1	7	32
Purchases		53	0	177	0
Issuances		0	0	0	0
Sales		(1)	0	(2)	0
Settlements		(8)	(13)	(24)	(29)
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Balance, end of period		416	313	416	313
Change in unrealized gains (losses) still held		7	(16)	35	252
Foreign currency swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	[1]	7	59	(21)	(192)
Realized gains or losses included in earnings	[1]	8	(18)	36	250
Unrealized gains or losses included in other comprehensive income (loss)	[1]	0	0	0	(16)
Purchases	[1]	0	0	0	0
Issuances	[1]	0	0	0	0
Sales	[1]	0	0	0	0
Settlements	[1]	0	0	0	(1)
Transfers into Level 3	[1]	0	0	0	0
Transfers out of Level 3	[1]	0	0	0	0
Balance, end of period	[1]	15	41	15	41
Changes in unrealized gain (losses) still held	[1]	8	(18)	36	250
Credit default swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	[1]	2	1	2	1
Realized gains or losses included in earnings	[1]	(1)	2	(1)	2
Unrealized gains or losses included in other comprehensive income (loss)	[1]	0	0	0	0
Purchases	[1]	0	0	0	0
Issuances	[1]	0	0	0	0
Sales	[1]	0	0	0	0
Settlements	[1]	0	0	0	0
Transfers into Level 3	[1]	0	0	0	0
Transfers out of Level 3	[1]	0	0	0	0
Balance, end of period	[1]	1	3	1	3
Changes in unrealized gain (losses) still held	[1]	(1)	2	(1)	2
Fixed maturities | Mortgage- and asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		188	252	198	220
Realized investment gains (losses) included in earnings		0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)		(2)	1	4	48
Purchases		0	0	0	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		(8)	(13)	(24)	(28)
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Balance, end of period		178	240	178	240
Change in unrealized gains (losses) still held		0	0	0	0
Fixed maturities | Public utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		53	0	16	0
Realized investment gains (losses) included in earnings		0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)		0	0	0	0
Purchases		24	0	61	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		0	0	0	0
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Balance, end of period		77	0	77	0
Change in unrealized gains (losses) still held		0	0	0	0
Fixed maturities | Banks/financial institutions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		25	26	25	26
Realized investment gains (losses) included in earnings		0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)		0	0	0	0
Purchases		0	0	0	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		0	0	0	0
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Balance, end of period		25	26	25	26
Change in unrealized gains (losses) still held		0	0	0	0
Fixed maturities | Other corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		77	0	0	0
Realized investment gains (losses) included in earnings		0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)		1	0	3	0
Purchases		25	0	100	0
Issuances		0	0	0	0
Sales		(1)	0	(1)	0
Settlements		0	0	0	0
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Balance, end of period		102	0	102	0
Change in unrealized gains (losses) still held		0	0	0	0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		14	3	3	3
Realized investment gains (losses) included in earnings		0	0	0	0
Unrealized gains (losses) included in other comprehensive income (loss)		0	0	0	0
Purchases		4	0	16	0
Issuances		0	0	0	0
Sales		0	0	(1)	0
Settlements		0	0	0	0
Transfers into Level 3		0	0	0	0
Transfers out of Level 3		0	0	0	0
Balance, end of period		18	3	18	3
Change in unrealized gains (losses) still held		$ 0	$ 0	$ 0	$ 0
[1]	Derivative assets and liabilities are presented net

FAIR VALUE MEASUREMENTS - Addit

FAIR VALUE MEASUREMENTS - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
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

FAIR VALUE MEASUREMENTS - Fai62

FAIR VALUE MEASUREMENTS - Fair Value Inputs Assets Quantitative Information (Details) - USD ($) $ / shares in Units, $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 83,206	$ 76,702
Asset derivatives		479	1,207
Assets, fair value		$ 88,669	$ 83,044
Length of Volatility of Japanese Yen to US Dollar Exchange Rate		10 years	10 years
Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 400	$ 242
Asset derivatives		148	127
Assets, fair value		548	369
Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		80,415	73,760
Fixed maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		382	239
Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		1,863	1,633
Perpetual securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		0	0
Equity securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		928	1,309
Equity securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		18	3
Equity securities | Net asset value valuation technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		18	3
Equity securities | Net asset value valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 18	$ 3
Equity securities | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Offered Quotes		$ 1	$ 1
Equity securities | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Offered Quotes		724	701
Equity securities | Assets | Weighted Average | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Offered Quotes		$ 6	$ 8
Mortgage- and asset-backed securities | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 456	$ 1,337
Mortgage- and asset-backed securities | Fixed maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		178	198
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		178	198
Mortgage- and asset-backed securities | Fixed maturities | Consensus pricing valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		178	198
Public utilities | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		8,015	7,683
Public utilities | Fixed maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		77	16
Public utilities | Fixed maturities | Discounted cash flow valuation technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		77	16
Public utilities | Fixed maturities | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		77	16
Banks/financial institutions | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		7,010	6,063
Banks/financial institutions | Fixed maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		25	25
Banks/financial institutions | Fixed maturities | Consensus pricing valuation technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		25	25
Banks/financial institutions | Fixed maturities | Consensus pricing valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		25	25
Banks/financial institutions | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		1,627	1,420
Banks/financial institutions | Perpetual securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		0	0
Other corporate | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		31,575	29,699
Other corporate | Fixed maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		102	0
Other corporate | Fixed maturities | Discounted cash flow valuation technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		102
Other corporate | Fixed maturities | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		102
Other corporate | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		236	213
Other corporate | Perpetual securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		0	0
Foreign currency swaps
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		301	490
Foreign currency swaps | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		147	125
Credit default swaps
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		1	2
Credit default swaps | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		1	2
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		$ 27	$ 16
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Foreign Exchange Rates	[1]	21.00%	21.47%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		0.11%	0.17%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		1.16%	1.72%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		$ 45	$ 29
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		0.11%	0.16%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		0.83%	0.88%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		$ 75	$ 80
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Foreign Exchange Rates	[1]	21.00%	21.47%
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives		$ 1	$ 2
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Assets | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		0.19%	0.54%
Fair Value Inputs, Recovery Rate		37.24%	36.69%
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Base Correlation	[2]	62.73%	52.18%
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Base Correlation	[2]	66.88%	56.07%
Dollar-denominated | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 38,017	$ 36,611
Dollar-denominated | Equity securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		280	604
Dollar-denominated | Mortgage- and asset-backed securities | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		179	216
Dollar-denominated | Public utilities | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		6,010	5,835
Dollar-denominated | Banks/financial institutions | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		3,268	3,061
Dollar-denominated | Banks/financial institutions | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		74	75
Dollar-denominated | Other corporate | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 27,018	$ 25,887
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	2.29%	2.34%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	2.53%	2.59%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	2.29%	2.34%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	2.53%	2.59%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	2.29%	2.34%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	2.53%	2.59%
Yen-denominated | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 42,398	$ 37,149
Yen-denominated | Equity securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		648	705
Yen-denominated | Mortgage- and asset-backed securities | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		277	1,121
Yen-denominated | Public utilities | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		2,005	1,848
Yen-denominated | Banks/financial institutions | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		3,742	3,002
Yen-denominated | Banks/financial institutions | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		1,553	1,345
Yen-denominated | Other corporate | Fixed maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		4,557	3,812
Yen-denominated | Other corporate | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities		$ 236	$ 213
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[4]	0.26%	0.22%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[4]	0.86%	0.80%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[4]	0.26%	0.22%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[4]	0.86%	0.80%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[4]	0.26%	0.22%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[4]	0.86%	0.80%
[1]	Based on 10 year volatility of JPY/USD exchange rate
[2]	Range of base correlation for the Company's bespoke tranche for attachment and detachment points corresponding to market indices.
[3]	Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps
[4]	Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps

FAIR VALUE MEASUREMENTS - Fai63

FAIR VALUE MEASUREMENTS - Fair Value Inputs Liabilities Quantitative Information (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liability derivatives		$ 974	$ 1,998
Liabilities, fair value disclosure		$ 974	$ 1,998
Length of Volatility of Japanese Yen to US Dollar Exchange Rate		10 years	10 years
Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liabilities, fair value disclosure		$ 132	$ 146
Foreign currency swaps
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liability derivatives		196	230
Foreign currency swaps | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liability derivatives		132	146
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liability derivatives		$ 112	$ 113
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Foreign Exchange Rates	[1]	21.00%	21.47%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		0.11%	0.17%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		1.16%	1.72%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liability derivatives		$ 11	$ 23
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		0.09%	0.24%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk		1.20%	2.16%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Discounted cash flow valuation technique | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Liability derivatives		$ 9	$ 10
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Liability | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Foreign Exchange Rates	[1]	21.00%	21.47%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[2]	2.29%	2.34%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[2]	2.53%	2.59%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[2]	2.29%	2.34%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[2]	2.53%	2.59%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[2]	2.29%	2.34%
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[2]	2.53%	2.59%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	0.26%	0.22%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	0.86%	0.80%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	0.26%	0.22%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and CDS Spread | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	0.86%	0.80%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Liability | Lower Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	0.26%	0.22%
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Liability | Upper Limit | Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	[3]	0.86%	0.80%
[1]	Based on 10 year volatility of JPY/USD exchange rate
[2]	Inputs derived from U.S. long-term rates to accommodate long maturity nature of the Company's swaps
[3]	Inputs derived from Japan long-term rates to accommodate long maturity nature of the Company's swaps

POLICY LIABILITIES - Changes in

POLICY LIABILITIES - Changes in Liability for Unpaid Policy Claims (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Liability for Unpaid Claims and Claims Expenses
Net balance, beginning of period			$ 4,045
Less claims paid during the period on claims incurred during:
Net balance, end of period	$ 4,368		4,368
Total liability for unpaid policy claims	4,368	$ 4,346	4,368	$ 4,346
Health insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of period	3,872	3,941	3,707	3,548
Less reinsurance recoverables	30	30	27	26
Net balance, beginning of period	3,842	3,911	3,680	3,522
Add claims incurred during the period related to:
Current year	1,759	1,843	5,278	5,309
Prior years	(126)	(148)	(386)	(374)
Total incurred	1,633	1,695	4,892	4,935
Less claims paid during the period on claims incurred during:
Current year	1,357	1,462	3,074	3,160
Prior years	234	232	1,697	1,722
Total paid	1,591	1,694	4,771	4,882
Effect of foreign exchange rate changes on unpaid claims	(14)	42	69	379
Net balance, end of period	3,870	3,954	3,870	3,954
Add reinsurance recoverables	30	31	30	31
Total liability for unpaid policy claims	3,900	3,985	3,900	3,985
Life insurance
Less claims paid during the period on claims incurred during:
Total liability for unpaid policy claims	$ 468	$ 361	$ 468	$ 361

POLICY LIABILITIES - Additional

POLICY LIABILITIES - Additional Information (Details) - Health insurance - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense	$ (126)	$ (148)	$ (386)	$ (374)
Aflac Japan
Liability for Future Policy Benefit, by Product Segment [Line Items]
Prior years claims and claims adjustment expense			$ (301)
Percentage of total prior year claims and claims adjustment expense			78.00%
Liability for unpaid claims and claims adjustment expense, foreign currency translation gain (loss)			$ (13)
Prior year claims and claims adjustment expense excluding effect of foreign currency			$ (315)
Percentage of total prior year claims and claims adjustment expense excluding effect of foreign currency			82.00%

REINSURANCE - Additional Infor

REINSURANCE - Additional Information (Details) $ in Millions, ¥ in Billions	9 Months Ended
	Sep. 30, 2017JPY (¥)	Sep. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Effects of Reinsurance [Line Items]
Percent change in spot yen/dollar exchange rate		3.00%
Percent change in ceded reserves		2.00%
Aflac Japan
Effects of Reinsurance [Line Items]
Committed reinsurance facility | ¥	¥ 110
Aflac Japan | Closed Block
Effects of Reinsurance [Line Items]
Reinsurance deferred profit liability		$ 942
Reinsurance recoverable		$ 906	$ 860

REINSURANCE - Effect of Reinsu

REINSURANCE - Effect of Reinsurance on Premiums and Benefits and Claims (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Effects of Reinsurance [Line Items]
Direct premium income	$ 4,734	$ 5,119	$ 14,210	$ 14,724
Net premium income	4,648	5,022	13,951	14,447
Direct benefits and claims	3,157	3,463	9,403	9,898
Benefits and claims, net	3,083	3,378	9,174	9,657
All other
Effects of Reinsurance [Line Items]
Ceded premiums	(12)	(13)	(37)	(37)
Assumed premiums earned	2	2	5	6
Ceded benefits and claims	(9)	(10)	(31)	(26)
Assumed benefits and claims from other companies	0	1	2	2
Aflac Japan
Effects of Reinsurance [Line Items]
Net premium income	3,200	3,596	9,616	10,177
Aflac Japan | Closed Block
Effects of Reinsurance [Line Items]
Ceded premiums	(130)	(148)	(390)	(423)
Assumed premiums earned	54	62	163	177
Ceded benefits and claims	(118)	(135)	(359)	(385)
Assumed benefits and claims from other companies	53	59	159	168
Intercompany eliminations
Effects of Reinsurance [Line Items]
Ceded benefits and claims	13	16	39	44
Assumed benefits and claims from other companies	$ (13)	$ (16)	$ (39)	$ (44)

NOTES PAYABLE - Additional Info

NOTES PAYABLE - Additional Information (Details) ¥ in Millions	1 Months Ended		9 Months Ended
	Feb. 28, 2017USD ($)	Jan. 31, 2017JPY (¥)	Sep. 30, 2017USD ($)	Sep. 30, 2017JPY (¥)	Dec. 31, 2016
2.65% senior notes paid February 2017
Debt Instrument [Line Items]
Debt instrument, interest rate	2.65%				2.65%
Repayments of debt	$ 650,000,000
.932% senior notes due January 2027
Debt Instrument [Line Items]
Debt instrument, principal amount | ¥		¥ 60,000		¥ 60,000
Debt instrument, interest rate		0.932%	0.932%	0.932%
Debt instrument, term		10 years
Notes payable
Debt Instrument [Line Items]
Debt instrument, debt default, amount			$ 0
$100 million dollar line of credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 100,000,000
Line of credit facility term			364 days
Line of credit facility, interest rate description			Borrowings will bear interest at the rate quoted by the bank and agreed upon at the time of making such loan and will have up to a three-month maturity period.
Line of credit facility, amount outstanding			$ 0
100.0 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity | ¥				¥ 100,000
Line of credit facility term			3 years
Line of credit facility, interest rate description			Borrowings bear interest at a rate per annum equal to the Tokyo interbank market rate (TIBOR) plus, at the Company's option, either (a) the applicable TIBOR margin during the period from the closing date to the commitment termination date or (b) the applicable TIBOR margin during the term out period. The applicable margin ranges between .35% and .75% during the period from the closing date to the commitment termination date and .70% and 1.50% during the term out period, depending on the Parent Company’s debt ratings as of the date of determination.
Line of credit facility, amount outstanding | ¥				0
55.0 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity | ¥				55,000
Line of credit facility term			5 years
Line of credit facility, interest rate description			Borrowings bear interest at a rate per annum equal to, at the Company's option, either (a) a eurocurrency rate determined by reference to the LIBOR for the interest period relevant to such borrowing adjusted for certain additional costs or (b) a base rate determined by reference to the highest of (1) the federal funds effective rate plus ½ of 1%, (2) the rate of interest for such day announced by Mizuho Bank, Ltd. as its prime rate and (3) the eurocurrency rate for an interest period of one month plus 1.00%, in each case plus an applicable margin. The applicable margin ranges between .79% and 1.275% for eurocurrency rate borrowings and 0.0% and .275% for base rate borrowings, depending on the Parent Company’s debt ratings as of the date of determination.
Line of credit facility, amount outstanding | ¥				¥ 0
$50 million dollar line of credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 50,000,000
Line of credit facility, interest rate description			Borrowings will bear interest at the rate quoted by the bank and agreed upon at the time of making such loan and will have up to a three-month maturity period.
Line of credit facility, amount outstanding			$ 0
Lines of credit
Debt Instrument [Line Items]
Debt instrument, debt default, amount			$ 0
Lower Limit | 100.0 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage			0.30%
Lower Limit | 55.0 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage			0.085%
Upper Limit | 100.0 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage			0.50%
Upper Limit | 55.0 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage			0.225%

NOTES PAYABLE - Summary of Note

NOTES PAYABLE - Summary of Notes Payable (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notes payable	$ 5,248	$ 5,360
2.65% senior notes paid February 2017
Debt Instrument [Line Items]
Notes payable	0	649
2.40% senior notes due March 2020
Debt Instrument [Line Items]
Notes payable	545	547
4.00% senior notes due February 2022
Debt Instrument [Line Items]
Notes payable	346	348
3.625% senior notes due June 2023
Debt Instrument [Line Items]
Notes payable	694	696
3.625% senior notes due November 2024
Debt Instrument [Line Items]
Notes payable	743	745
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Notes payable	445	445
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Notes payable	298	298
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Notes payable	221	220
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Notes payable	256	254
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Notes payable	394	394
5.50% subordinated notes due September 2052
Debt Instrument [Line Items]
Notes payable	494	486
.932% senior notes due January 2027
Debt Instrument [Line Items]
Notes payable	529	0
Yen-denominated loan variable interest rate due September 2021
Debt Instrument [Line Items]
Notes payable	44	43
Yen-denominated loan variable interest rate due September 2023
Debt Instrument [Line Items]
Notes payable	221	214
Capitalized lease obligations
Debt Instrument [Line Items]
Notes payable	$ 18	$ 21

NOTES PAYABLE - Summary of No70

NOTES PAYABLE - Summary of Notes Payable (Parenthetical) (Details) $ in Millions, ¥ in Billions	Sep. 30, 2017USD ($)	Sep. 30, 2017JPY (¥)	Feb. 28, 2017	Jan. 31, 2017JPY (¥)	Dec. 31, 2016JPY (¥)
2.65% senior notes paid February 2017
Debt Instrument [Line Items]
Debt instrument, interest rate			2.65%		2.65%
2.40% senior notes due March 2020
Debt Instrument [Line Items]
Debt instrument, interest rate	2.40%	2.40%			2.40%
Debt instrument, principal amount	$ 550
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%
5.50% subordinated notes due September 2052
Debt Instrument [Line Items]
Debt instrument, interest rate	5.50%	5.50%			5.50%
Debt instrument, principal amount	$ 500
.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
Yen-denominated loan variable interest rate due September 2021
Debt Instrument [Line Items]
Debt instrument, interest rate	0.31%	0.31%			0.31%
Debt instrument, principal amount | ¥		¥ 5			¥ 5
Yen-denominated loan variable interest rate due September 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	0.46%	0.46%			0.46%
Debt instrument, principal amount | ¥		¥ 25			¥ 25

SHAREHOLDERS' EQUITY - Reconcil

SHAREHOLDERS' EQUITY - Reconciliation of Number of Shares of Common Stock (Detail) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Common Stock Issued [Roll Forward]
Balance, beginning of period	671,249	669,723
Exercise of stock options and issuance of restricted shares	1,420	1,261
Balance, end of period	672,669	670,984
Treasury Stock [Roll Forward]
Balance, beginning of period	265,439	245,343
Balance, end of period	278,794	262,963
Shares outstanding, end of period	393,875	408,021
Treasury Stock
Treasury Stock [Roll Forward]
Stock Acquired In Open Market, Shares	13,898	18,774
Other purchases	435	329
Shares issued to AFL Stock Plan	(696)	(822)
Exercise of stock options	(263)	(554)
Other dispositions	(19)	(107)

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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Stockholders' Equity Note [Abstract]
Anti-dilutive share-based awards	266	109	335	1,162

SHAREHOLDERS' EQUITY - Addition

SHAREHOLDERS' EQUITY - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Stockholders Equity Note [Line Items]
Common stock, share repurchase, dollar amount	$ 1,053	$ 1,222
Remaining common stock available for purchase under share repurchase authorizations	52.9
Share Repurchase Program
Stockholders Equity Note [Line Items]
Stock Acquired In Open Market, Shares	13.9	18.8
Common stock, share repurchase, dollar amount	$ 1,000	$ 1,200
Share Repurchase Authorization 2017
Stockholders Equity Note [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	40

SHAREHOLDERS' EQUITY - Changes

SHAREHOLDERS' EQUITY - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	$ 3,401	$ 5,432	$ 2,630	$ 625
Other comprehensive income loss before reclassifications net of tax	[1]	159	(90)	914	4,757
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	(29)	22	(13)	(18)
Other comprehensive income (loss), net of tax	[1]	130	(68)	901	4,739
Balance, end of period	[1]	3,531	5,364	3,531	5,364
Unrealized foreign currency translation gains (losses)
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	(1,580)	(847)	(1,983)	(2,196)
Other comprehensive income loss before reclassifications net of tax	[1]	(135)	253	268	1,602
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	0	0	0	0
Other comprehensive income (loss), net of tax	[1]	(135)	253	268	1,602
Balance, end of period	[1]	(1,715)	(594)	(1,715)	(594)
Unrealized gains (losses) on investment securities
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	5,173	6,441	4,805	2,986
Other comprehensive income loss before reclassifications net of tax	[1]	296	(342)	653	3,155
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	(32)	21	(21)	(21)
Other comprehensive income (loss), net of tax	[1]	264	(321)	632	3,134
Balance, end of period	[1]	5,437	6,120	5,437	6,120
Unrealized gains (losses) on derivatives
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	(23)	(19)	(24)	(26)
Other comprehensive income loss before reclassifications net of tax	[1]	0	0	1	7
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	0	0	0	0
Other comprehensive income (loss), net of tax	[1]	0	0	1	7
Balance, end of period	[1]	(23)	(19)	(23)	(19)
Pension liability adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Balance, beginning of period	[1]	(169)	(143)	(168)	(139)
Other comprehensive income loss before reclassifications net of tax	[1]	(2)	(1)	(8)	(7)
Amounts reclassified from accumulated other comprehensive income net of tax	[1]	3	1	8	3
Other comprehensive income (loss), net of tax	[1]	1	0	0	(4)
Balance, end of period	[1]	$ (168)	$ (143)	$ (168)	$ (143)
[1]	All amounts in the table above are net of tax.

SHAREHOLDERS' EQUITY - Reclassi

SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and redemptions		$ 61	$ (14)	$ 60	$ 100
Other than temporary impairment losses realized		(8)	(23)	(27)	(71)
Total before tax		1,075	963	3,019	2,914
Income tax (expense) or benefit		(359)	(334)	(998)	(1,006)
Net of tax		$ 716	$ 629	$ 2,021	$ 1,908
The expected U.S. tax rate		35.00%	35.00%	35.00%	35.00%
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		$ 29	$ (22)	$ 13	$ 18
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized gains (losses) on investment securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and redemptions		56	(11)	56	102
Other than temporary impairment losses realized		(6)	(22)	(23)	(69)
Total before tax		50	(33)	33	33
Income tax (expense) or benefit	[1]	(18)	12	(12)	(12)
Net of tax		32	(21)	21	21
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)	[2]	(4)	(4)	(12)	(12)
Acquisition and operating expenses, prior service (cost) credit	[2]	0	2	0	8
Income tax (expense) or benefit	[1]	1	1	4	1
Net of tax		$ (3)	$ (1)	$ (8)	$ (3)
[1]	Based on 35% 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).

SHARE-BASED COMPENSATION - Addi

SHARE-BASED COMPENSATION - Additional Information (Detail) - USD ($) shares in Thousands, $ in Millions	1 Months Ended	9 Months Ended
	Feb. 28, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock options exercised		$ 48	$ 59
Tax benefit from exercise of stock options		$ 37	$ 29
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		37,500
Share-based compensation arrangement by share-based payment award, maximum number of shares issuable other than options and stock appreciation rights		19,000
Shares available for future grants under the long-term incentive plan		20,600
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		$ 43
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number, shares		1,858		1,868
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition		1 year 1 month 6 days
Restricted stock awards, grants in period		555
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		$ 17
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number, shares		968
Restricted stock awards, grants in period	253

SHARE-BASED COMPENSATION - Stoc

SHARE-BASED COMPENSATION - Stock Options Outstanding and Exercisable (Detail) $ / shares in Units, shares in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options Outstanding - Stock Option Shares | shares	4,181
Options Outstanding - Weighted-Average Remaining Term (Yrs)	5 years 4 months 24 days
Options Outstanding - Aggregate Intrinsic Value | $	$ 108
Options Outstanding - Weighted-Average Exercise Price Per Share | $ / shares	$ 55.61
Options Exercisable - Stock Option Shares | shares	2,563
Options Exercisable - Weighted-Average Remaining Term (Yrs.)	3 years 7 months 6 days
Options Exercisable - Aggregate Intrinsic Value | $	$ 79
Options Exercisable - Weighted-Average Exercise Price Per Share | $ / shares	$ 50.73

SHARE-BASED COMPENSATION - Rest

SHARE-BASED COMPENSATION - Restricted Stock Activity (Details) - Restricted Stock shares in Thousands	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Shares
Beginning Balance | shares	1,868
Granted | shares	555
Canceled | shares	(79)
Vested | shares	(486)
Ending Balance | shares	1,858
Weighted-Average Grant-Date Fair Value Per Share
Beginning Balance | $ / shares	$ 61.76
Granted | $ / shares	72.85
Cancelled | $ / shares	64.22
Vested | $ / shares	62.22
Ending Balance | $ / shares	$ 64.71

BENEFIT PLANS - Additional Info

BENEFIT PLANS - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	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
Lower Limit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Health care plan, retirement age for eligibility, (in years)		55 years
Health care plan, number of years of service for eligibility		15 years
Health care plan, retirement age and years of service combined years for eligibility (rule of 80)		80 years
Japan | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 18
U.S. | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions	$ 40

BENEFIT PLANS - Net Periodic (B

BENEFIT PLANS - Net Periodic (Benefit) Cost Included in Acquisition and Operating Expenses (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	0	0	1	1
Expected return on plan assets	0	0	0	0
Amortization of net actuarial loss	0	0	0	1
Amortization of prior service cost (credit)	0	(2)	0	(8)
Net periodic (benefit) cost	0	(2)	1	(6)
Japan | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	4	4	13	12
Interest cost	2	2	5	5
Expected return on plan assets	(1)	(1)	(3)	(3)
Amortization of net actuarial loss	1	0	2	1
Amortization of prior service cost (credit)	0	0	0	0
Net periodic (benefit) cost	6	5	17	15
U.S. | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6	5	18	17
Interest cost	8	8	24	24
Expected return on plan assets	(6)	(6)	(17)	(17)
Amortization of net actuarial loss	3	4	10	10
Amortization of prior service cost (credit)	0	0	0	0
Net periodic (benefit) cost	$ 11	$ 11	$ 35	$ 34

COMMITMENTS AND CONTINGENT LI81

COMMITMENTS AND CONTINGENT LIABILITIES - Additional Information (Details) $ in Millions, ¥ in Billions	3 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2017JPY (¥)	Mar. 31, 2017USD ($)
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, discounted amount of insurance-related assessment liability, payment period (in years)			1
Loss contingency, discounted amount of insurance-related assessment liability, realization period for associated asset offsets (in years)			5
Loss contingency, loss in period			$ 14
Information technology and data services company application maintenance and development services agreement
Commitments And Contingencies Disclosure [Line Items]
Outsourcing agreements, remaining term	5 years	5 years
Outsourcing agreements, aggregate remaining cost	$ 69	¥ 7.8

SUBSEQUENT EVENTS Additional In

SUBSEQUENT EVENTS Additional Information (Detail) - 2.108% senior notes due October 2047 - Subsequent events ¥ in Billions	1 Months Ended
	Oct. 31, 2017JPY (¥)
Subsequent Event [Line Items]
Debt instrument, principal amount	¥ 60
Debt instrument, interest rate terms	The debentures bear interest at an initial rate of 2.108% per annum through October 22, 2027, or earlier redemption. Thereafter, the rate of the interest of the debentures will be reset every five years at a rate of interest equal to the then-current JPY 5-year Swap Offered Rate plus 205 basis points.
Debt instrument, term	30 years
Debt instrument, redemption, description	The debentures are redeemable (i) at any time, in whole but not in part, upon the occurrence of certain tax events or certain rating agency events, as specified in the indenture governing the terms of the debentures or (ii) in 10 years, in whole or in part, at a redemption price equal to their principal amount plus accrued and unpaid interest to, but excluding, the date of redemption.