Line of credit facility amount of option to increase additional borrowings.

No definition available.

Name:	gpc_LineOfCreditFacilityAmountOfOptionToIncreaseAdditionalBorrowings
Namespace Prefix:	gpc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

Incremental percentage increase (decrease) in the stated rate on a debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentInterestRateIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- 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 carrying value as of the balance sheet date of the current portion 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 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: 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(19))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

+ Details

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

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

Reference 1: 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(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=gpc_ExistingPrivatePlacementDebtMember
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Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=gpc_A2012CreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=gpc_SeriesJSeniorUnsecuredNotesMember
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- Details

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- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=gpc_SeniorFixedRateNotesMember
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Balance Type:
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- Details

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Credit Facilities - Additional Information (Detail)	12 Months Ended
Credit Facilities - Additional Information (Detail)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Oct. 30, 2017 USD ($)	Oct. 30, 2017 EUR (€)	Oct. 29, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Long-term debt, bearing variable interest, amount	$ 1,690,000,000					$ 325,000,000
Weighted average interest rate on outstanding borrowings	2.70%	2.70%				2.39%
Unused letter of credit outstanding due to workers' compensation and insurance reserve	$ 62,019,000					$ 64,930,000
Syndicated Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 2,600,000,000
Line of credit facility, interest rate at period end	2.69%	2.69%
Line of credit facility amount of option to increase additional borrowing	$ 1,000,000,000
Existing Placement Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 550,000,000
Interest rate, increase (decrease)	0.25%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,500,000,000
Revolving Credit Facility [Member] \| 2012 Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 1,200,000,000
Revolving Credit Facility [Member] \| Syndicated Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			1,500,000,000
Line of credit, current	590,000,000					325,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	1,100,000,000
Term Loan [Member] \| Syndicated Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			1,100,000,000
Unsecured debt	1,100,000,000					$ 0
Series J Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €		€ 225,000,000
Series K Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €		250,000,000
Series I Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 120,000,000
Series L Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €		125,000,000
Series M Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €		€ 100,000,000
Senior Notes [Member] \| Series J Senior Unsecured Notes [Member] \| Senior Fixed Rate Notes [Member] \| October 30, 2024 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €				€ 225,000,000
Senior Notes [Member] \| Series K Senior Unsecured Notes [Member] \| Senior Fixed Rate Notes [Member] \| October 30, 2027 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €				250,000,000
Senior Notes [Member] \| Series I Senior Unsecured Notes [Member] \| Senior Fixed Rate Notes [Member] \| October 30, 2027 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 120,000,000
Senior Notes [Member] \| Series L Senior Unsecured Notes [Member] \| Senior Fixed Rate Notes [Member] \| October 30, 2029 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €				125,000,000
Senior Notes [Member] \| Series M Senior Unsecured Notes [Member] \| Senior Fixed Rate Notes [Member] \| October 30, 2032 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €				€ 100,000,000