Year when debt instrument is scheduled to be fully repaid.

No definition available.

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Period Type:	duration

- Definition

Year the entity entered into the derivative contract, in CCYY format.

+ References

No definition available.

+ Details

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Namespace Prefix:	lyb_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- 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

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- Details

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- Details

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- Details

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- Details

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Debt, Description of fair value adjustments for senior and guaranteed notes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended	24 Months Ended	27 Months Ended	36 Months Ended	39 Months Ended	48 Months Ended	51 Months Ended	72 Months Ended	75 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Debt Instrument [Line Items]
Gain (loss) on fair value adjustments of the hedged item related to interest rate swaps	$ (95)	$ (40)								$ (40)	$ (135)
Senior Notes due 2019, $1,000 million, 5.0% [Member]
Debt Instrument [Line Items]
Maturity year			2019
Stated interest rate (in hundredths)			5.00%	5.00%		5.00%		5.00%		5.00%
Inception year			2014
Gain (loss) on fair value adjustments of the hedged item related to interest rate swaps	$ 0	(11)								$ 0	$ 0
Senior Notes due 2021, $1,000 million, 6.0% [Member]
Debt Instrument [Line Items]
Maturity year	2021
Stated interest rate (in hundredths)	6.00%				6.00%		6.00%		6.00%		6.00%
Inception year	2016
Gain (loss) on fair value adjustments of the hedged item related to interest rate swaps	$ (16)	(7)						$ (1)	$ (17)
Guaranteed Notes due 2027, $1,000 million, 3.5% [Member]
Debt Instrument [Line Items]
Maturity year	2027
Stated interest rate (in hundredths)	3.50%				3.50%		3.50%		3.50%		3.50%
Inception year	2017
Gain (loss) on fair value adjustments of the hedged item related to interest rate swaps	$ (80)	(22)				$ (37)	$ (117)
Guaranteed Notes due 2022, Euro 750 million, 1.875% [Member]
Debt Instrument [Line Items]
Maturity year	2022
Stated interest rate (in hundredths)	1.875%				1.875%		1.875%		1.875%		1.875%
Inception year	2018
Gain (loss) on fair value adjustments of the hedged item related to interest rate swaps	$ 1	$ 0		$ (2)	$ (1)