Effective interest rate percentage on a debt instrument after entering into an interest rate swap.

No definition available.

Name:	afl_DebtInstrumentEffectiveInterestRatePercentageAfterInterestRateSwap
Namespace Prefix:	afl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument Effective Principal Amount After Cross Currency Swap

+ References

No definition available.

+ Details

Name:	afl_DebtInstrumentEffectivePrincipalAmountAfterCrossCurrencySwap
Namespace Prefix:	afl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of credit facility term

+ References

No definition available.

+ Details

Name:	afl_Lineofcreditfacilityterm
Namespace Prefix:	afl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum principal amount outstanding following partial redemption

+ References

No definition available.

+ Details

Name:	afl_Minimumprincipalamountoutstandingfollowingpartialredemption
Namespace Prefix:	afl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of Series of Senior Notes Issued Through a U.S. Public Debt Offering

+ References

No definition available.

+ Details

Name:	afl_NumberOfSeriesOfSeniorNotesIssuedThroughUSPublicDebtOffering
Namespace Prefix:	afl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Series of Senior Unsecured Term Loan Facilities

+ References

No definition available.

+ Details

Name:	afl_NumberofSeriesofSeniorUnsecuredTermLoanFacilities
Namespace Prefix:	afl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of outstanding long-term debt or borrowing associated with any securities or credit agreement for which there has been a default in principal, interest, sinking fund, or redemption provisions, or any breach of covenant that existed at the end of the period and subsequently has not been cured.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(c))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_DebtDefaultLongtermDebtAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of debt redemption features under terms of the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesTwoPointEightSevenFivePercentDueOctoberTwentyTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesFourPointZeroZeroPercentDueOctoberTwentyFortySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_YendenominatedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_YendenominatedLoanVariableInterestRateDueSeptemberTwentyTwentyOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_YendenominatedLoanVariableInterestRateDueSeptemberTwentyTwentyThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesTwoPointFourZeroPercentDueMarchTwentyTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesThreePointTwoFivePercentDueMarchTwentyTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesThreePointSixTwoFivePercentDueNovemberTwentyTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesThreePointSixTwoFivePercentDueJuneTwentyTwentyThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SubordinatedNotesFivePointFiveZeroPercentDueSeptemberTwentyFiftyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesTwoPointSixFivePercentDueFebruaryTwentySeventeenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesFourPointZeroZeroPercentDueFebruaryTwentyTwentyTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesSixPointNineZeroPercentDueDecemberTwentyThirtyNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesSixPointFourFivePercentDueAugustTwentyFortyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_SeniorNotesdueTwoThousandThirtyNineandTwoThousandandFortyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_YenDenominatedUridashiNotesTwoPointTwoSixPercentDueSeptemberTwentySixteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=afl_YenDenominatedSamuraiNotesOnePointEightFourPercentDueJulyTwentySixteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_NotesPayableOtherPayablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=afl_OnehundredmilliondollarlineofcreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=afl_OnehundredbillionyenlineofcreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=afl_FiftyfivebillionyenlineofcreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=afl_FiftymilliondollarlineofcreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

NOTES PAYABLE - Additional Information (Detail) ¥ in Millions	1 Months Ended												3 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 JPY (¥)	Jul. 31, 2016 JPY (¥)	Mar. 31, 2015 USD ($) series	Nov. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)	Oct. 31, 2012 USD ($)	Sep. 30, 2012 USD ($)	Jul. 31, 2012 USD ($)	Feb. 29, 2012 USD ($) series	Aug. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 JPY (¥)	Sep. 30, 2016 USD ($) series	Sep. 30, 2016 JPY (¥) series	Dec. 31, 2015 USD ($)	Dec. 31, 2015 JPY (¥)	Mar. 31, 2015 JPY (¥) series	Nov. 30, 2014 JPY (¥)	Jun. 30, 2013 JPY (¥)	Oct. 31, 2012 JPY (¥)	Sep. 30, 2012 JPY (¥)	Feb. 29, 2012 JPY (¥) series
Debt Instrument [Line Items]
Number of series of senior unsecured term loan facilities \| series																2	2
Number of series of senior notes issued through a U.S. public debt offering (in series) \| series				2						2						2	2			2					2
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Debt instrument, interest rate	2.875%												2.875%	2.875%	2.875%	2.875%	2.875%
Debt instrument, term		10 years
Debt instrument, principal amount																$ 300,000,000
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%												4.00%	4.00%	4.00%	4.00%	4.00%
Debt instrument, term		30 years
Debt instrument, principal amount																$ 400,000,000
Yen-denominated Loans
Debt Instrument [Line Items]
Debt instrument, principal amount \| ¥																	¥ 30,000
Yen-denominated loan variable interest rate due September 2021
Debt Instrument [Line Items]
Debt instrument, interest rate	0.31%												0.31%	0.31%	0.31%
Debt instrument, principal amount \| ¥															¥ 5,000		5,000
Debt instrument, interest rate terms		bears an interest rate per annum equal to the Tokyo interbank market rate (TIBOR), or alternate TIBOR, if applicable, plus the applicable TIBOR margin and has a five-year maturity. The applicable margin ranges between .20% and .60%, depending on the Parent Company's debt ratings as of the date of determination.
Yen-denominated loan variable interest rate due September 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	0.46%												0.46%	0.46%	0.46%
Debt instrument, principal amount \| ¥															¥ 25,000		¥ 25,000
Debt instrument, interest rate terms		bears an interest rate per annum equal to TIBOR, or alternate TIBOR, if applicable, plus the applicable TIBOR margin and has a seven-year maturity. The applicable margin ranges between .35% and .75%, depending on the Parent Company's debt ratings as of the date of determination.
2.40% senior notes due March 2020
Debt Instrument [Line Items]
Debt instrument, interest rate	2.40%			2.40%									2.40%	2.40%	2.40%			2.40%	2.40%	2.40%
Debt instrument, term				5 years
Debt instrument effective principal amount after cross currency swap \| ¥																				¥ 67,000
Debt instrument, principal amount	$ 550,000,000			$ 550,000,000									$ 550,000,000	$ 550,000,000
Debt instrument, effective interest rate				0.24%																0.24%
3.25% senior notes due March 2025
Debt Instrument [Line Items]
Debt instrument, interest rate	3.25%			3.25%									3.25%	3.25%	3.25%			3.25%	3.25%	3.25%
Debt instrument, term				10 years
Debt instrument effective principal amount after cross currency swap \| ¥																				¥ 55,000
Debt instrument, principal amount	$ 450,000,000			$ 450,000,000									$ 450,000,000	$ 450,000,000
Debt instrument, effective interest rate				0.82%																0.82%
3.625% senior notes due November 2024
Debt Instrument [Line Items]
Debt instrument, interest rate	3.625%				3.625%								3.625%	3.625%	3.625%			3.625%	3.625%		3.625%
Debt instrument, term					10 years
Debt instrument, redemption, description					These notes are redeemable at our option in whole at any time or in part from time to time at a redemption price equal to the greater of: (i) the aggregate principal amount of the notes to be redeemed or (ii) the amount equal to the sum of the present values of the remaining scheduled payments for principal of and interest on the notes to be redeemed, not including any portion of the payments of interest accrued as of such redemption date, discounted to such redemption date on a semiannual basis at the treasury rate plus 20 basis points, plus in each case, accrued and unpaid interest on the principal amount of the notes to be redeemed to, but excluding, such redemption date.
Debt instrument effective principal amount after cross currency swap \| ¥																					¥ 85,300
Debt instrument, principal amount	$ 750,000,000				$ 750,000,000								$ 750,000,000	$ 750,000,000
Debt instrument, effective interest rate					1.00%																1.00%
3.625% senior notes due June 2023
Debt Instrument [Line Items]
Debt instrument, interest rate	3.625%					3.625%							3.625%	3.625%	3.625%			3.625%	3.625%			3.625%
Debt instrument, term						10 years
Debt instrument, redemption, description						These notes are redeemable at our option in whole at any time or in part from time to time at a redemption price equal to the greater of: (i) the aggregate principal amount of the notes to be redeemed or (ii) the amount equal to the sum of the present values of the remaining scheduled payments for principal of and interest on the notes to be redeemed, not including any portion of the payments of interest accrued as of such redemption date, discounted to such redemption date on a semiannual basis at the treasury rate plus 20 basis points, plus in each case, accrued and unpaid interest on the principal amount of the notes to be redeemed to, but excluding, such redemption date.
Debt instrument effective principal amount after cross currency swap \| ¥																						¥ 69,800
Debt instrument, principal amount	$ 700,000,000					$ 700,000,000							$ 700,000,000	$ 700,000,000
Debt instrument, effective interest rate						1.50%																1.50%
5.50% subordinated notes due September 2052
Debt Instrument [Line Items]
Debt instrument, interest rate	5.50%						5.50%	5.50%					5.50%	5.50%	5.50%			5.50%	5.50%				5.50%	5.50%
Debt instrument, term								40 years
Debt instrument effective principal amount after cross currency swap \| ¥																							¥ 3,900	¥ 35,300
Debt instrument, principal amount	$ 500,000,000						$ 50,000,000	$ 450,000,000					$ 500,000,000	$ 500,000,000
Minimum prinicipal amount outstanding following partial redemption								$ 25,000,000
Debt instrument, effective interest rate							4.42%	4.41%															4.42%	4.41%
Derivative, term of contract							5 years	5 years
2.65% senior notes due February 2017
Debt Instrument [Line Items]
Debt instrument, interest rate	2.65%								2.65%	2.65%			2.65%	2.65%	2.65%			2.65%	2.65%						2.65%
Debt instrument, term									5 years	5 years
Debt instrument effective principal amount after cross currency swap \| ¥																									¥ 30,900
Debt instrument, principal amount	$ 400,000,000								$ 250,000,000	$ 400,000,000			$ 400,000,000	$ 400,000,000
Debt instrument, effective interest rate										1.22%															1.22%
4.00% senior notes due February 2022
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%									4.00%			4.00%	4.00%	4.00%			4.00%	4.00%						4.00%
Debt instrument, term										10 years
Debt instrument effective principal amount after cross currency swap \| ¥																									¥ 27,000
Debt instrument, principal amount	$ 350,000,000									$ 350,000,000			$ 350,000,000	$ 350,000,000
Debt instrument, effective interest rate										2.07%															2.07%
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Repayments of debt	$ 176,000,000
Debt instrument, interest rate	6.90%												6.90%	6.90%	6.90%			6.90%	6.90%
Debt instrument, term												30 years
Debt instrument, principal amount												$ 400,000,000
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Repayments of debt	$ 193,000,000
Debt instrument, interest rate	6.45%												6.45%	6.45%	6.45%			6.45%	6.45%
Debt instrument, term											30 years
Debt instrument, principal amount											$ 450,000,000
Senior Notes due 2039 and 2040
Debt Instrument [Line Items]
Expense on extinguishment of debt														$ 137,000,000
2.26% yen-denominated Uridashi notes paid September 2016
Debt Instrument [Line Items]
Repayments of debt \| ¥		¥ 8,000
Debt instrument, interest rate																2.26%	2.26%	2.26%	2.26%
Debt instrument, principal amount \| ¥																			¥ 8,000
1.84% yen-denominated Samurai notes paid July 2016
Debt Instrument [Line Items]
Repayments of debt \| ¥			¥ 15,800
Debt instrument, interest rate			1.84%															1.84%	1.84%
Debt instrument, principal amount \| ¥																			¥ 15,800
Senior Notes
Debt Instrument [Line Items]
Debt instrument, principal amount				$ 1,000,000,000						$ 750,000,000						$ 700,000,000
Notes Payable
Debt Instrument [Line Items]
Debt instrument, debt default, amount	$ 0												$ 0	0				$ 0
Lines of credit
Debt Instrument [Line Items]
Debt instrument, debt default, amount	0												$ 0	0				$ 0
$100 million dollar line of credit
Debt Instrument [Line Items]
Line of credit facility term													364 days
Line of credit facility, maximum borrowing capacity	100,000,000												$ 100,000,000	100,000,000
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												$ 0	$ 0
100 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility term														3 years
Line of credit facility, maximum borrowing capacity \| ¥															¥ 100,000
Line of credit facility, interest rate description														Borrowings bear interest at a rate per annum equal to TIBOR plus, at our 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 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility term														5 years
Line of credit facility, maximum borrowing capacity \| ¥															55,000
Line of credit facility, interest rate description														Borrowings bear interest at a rate per annum equal to, at our 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												50,000,000	$ 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												$ 0	$ 0
Upper Limit \| 100 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage														0.50%
Upper Limit \| 55 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage														0.225%
Lower Limit \| 100 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage														0.30%
Lower Limit \| 55 billion yen line of credit
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage														0.085%