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OPERATING SEGMENT INFORMATION - Segment Revenue (Details) - EUR (€) € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure of operating segments [line items]
Revenue	€ 1,518	€ 1,031	€ 2,859	€ 2,468
P&ARP
Disclosure of operating segments [line items]
Revenue	904	564	1,668	1,313
A&T
Disclosure of operating segments [line items]
Revenue	274	247	508	596
AS&I
Disclosure of operating segments [line items]
Revenue	340	220	683	559
Segment revenue
Disclosure of operating segments [line items]
Revenue	1,539	1,037	2,900	2,490
Segment revenue | P&ARP
Disclosure of operating segments [line items]
Revenue	907	565	1,673	1,317
Segment revenue | A&T
Disclosure of operating segments [line items]
Revenue	287	250	532	609
Segment revenue | AS&I
Disclosure of operating segments [line items]
Revenue	345	222	695	564
Inter-segment elimination
Disclosure of operating segments [line items]
Revenue	(21)	(6)	(41)	(22)
Inter-segment elimination | P&ARP
Disclosure of operating segments [line items]
Revenue	(3)	(1)	(5)	(4)
Inter-segment elimination | A&T
Disclosure of operating segments [line items]
Revenue	(13)	(3)	(24)	(13)
Inter-segment elimination | AS&I
Disclosure of operating segments [line items]
Revenue	€ (5)	€ (2)	€ (12)	€ (5)

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- Definition

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

+ References

No definition available.

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- Definition

The amount of revenue from contracts with customers. A customer is a party that has contracted with an entity to obtain goods or services that are an output of the entity’s ordinary activities in exchange for consideration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2020-01-01
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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