Financial Instruments and Fair Value Measurements, Interest Rate Swaps (Details) $ in Millions	12 Months Ended
Sep. 28, 2019 USD ($)	Sep. 29, 2018 USD ($) Instrument
Interest Rate Swaps [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Number of derivative instruments settled \| Instrument		2
Interest Rate Swap Expiring June 2019 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Cash received for settlement of derivative contract		$ 9
Interest Rate Swap Expiring September 2021 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Cash received for settlement of derivative contract		21
Interest Rate Swap Expiring September 2021 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Notional amount of swap	$ 1,000	$ 1,000
Fixed annual rate of swap	2.808%	2.808%
Interest Rate Swap Expiring September 2021 [Member] \| LIBOR [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Term of variable rate	1 month	1 month
Interest Rate Swap Expiring July 2023 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Notional amount of swap	$ 400
Fixed annual rate of swap	2.533%
Interest Rate Swap Expiring July 2023 [Member] \| LIBOR [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Term of variable rate	1 month
Interest Rate Swap Expiring June 2024 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Notional amount of swap	$ 884
Fixed annual rate of swap	4.357%
Interest Rate Swap Expiring June 2024 [Member] \| LIBOR [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Term of variable rate	1 month
Basis spread	2.50%
Interest Rate Swap Expiring June 2024 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Notional amount of swap	$ 473
Fixed annual rate of swap	4.55%
Interest Rate Swap Expiring June 2024 [Member] \| LIBOR [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Term of variable rate	1 month
Basis spread	2.50%
Interest Rate Swap Expiring May 2022 [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Notional amount of swap	$ 450
Fixed annual rate of swap	2.00%
Interest Rate Swap Expiring May 2022 [Member] \| LIBOR [Member]
Cross-Currency and Interest Rate Swaps [Abstract]
Term of variable rate	1 month

Term of the interest rate that fluctuates over time as a result of an underlying benchmark interest rate or index.

No definition available.

Name:	bery_DebtInstrumentTermOfVariableRate
Namespace Prefix:	bery_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of derivative instruments settled during the period.

+ References

No definition available.

+ Details

Name:	bery_NumberOfDerivativeInstrumentsSettled
Namespace Prefix:	bery_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

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

- Definition

The amount of cash received during the period on settlement of a hedge.

+ References

No definition available.

+ Details

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

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bery_InterestRateSwapExpiringJune2019Member
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bery_InterestRateSwap1ExpiringSeptember2021Member
Namespace Prefix:
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bery_InterestRateSwap2ExpiringSeptember2021Member
Namespace Prefix:
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- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bery_InterestRateSwapExpiringJuly2023Member
Namespace Prefix:
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bery_InterestRateSwap1ExpiringJune2024Member
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- Details

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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bery_InterestRateSwapExpiringMay2022Member
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