Property, Plant and Equipment - Summary of Detailed Information About Lease And Own Assets (Detail) - EUR (€) € in Millions	Dec. 31, 2020	Dec. 31, 2019
Property, plant and equipment [abstract]
Property, plant and equipment	€ 10,558	€ 12,062
Owned assets [Member]
Property, plant and equipment [abstract]
Property, plant and equipment	8,909	10,249
Lease assets [Member]
Property, plant and equipment [abstract]
Property, plant and equipment	€ 1,649	€ 1,813

The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2020-01-01
-Paragraph 73
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_73_e&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 54
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_a&doctype=Standard
-URIDate 2020-01-01

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