Investments in joint ventures - Summarized aggregate financial information of joint ventures (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of joint ventures [line items]
Earnings from joint ventures – after interest and tax	$ 543	$ (302)	$ 576
Investments in joint ventures	9,982	8,362
Pan American Energy Group [Member]
Disclosure of joint ventures [line items]
Earnings from joint ventures – after interest and tax	(217)	(208)	97
Investments in joint ventures	4,396	4,613
Other joint ventures
Disclosure of joint ventures [line items]
Earnings from joint ventures – after interest and tax	760	(94)	479
Investments in joint ventures	5,586	3,749
Joint ventures
Disclosure of joint ventures [line items]
Earnings from joint ventures – after interest and tax	543	(302)	$ 576
Investments in joint ventures	$ 9,982	$ 8,362

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

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfJointVenturesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of investments in joint ventures accounted for using the equity method. [Refer: Joint ventures [member]; Investments accounted for using equity method]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_55&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_InvestmentsInJointVenturesAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The entity's share of the profit (loss) of joint ventures accounted for using the equity method. [Refer: Investments accounted for using equity method; Joint ventures [member]; Profit (loss)]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 85
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_85&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_ShareOfProfitLossOfJointVenturesAccountedForUsingEquityMethod
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	ifrs-full_JointVenturesAxis=bp_PanAmericanEnergyGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_JointVenturesAxis=ifrs-full_AggregatedIndividuallyImmaterialJointVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_JointVenturesAxis=ifrs-full_JointVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: