Balances under contracts with customers and other ifrs 15 disclosures (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	€ 9,024.0	€ 8,339.0	€ 7,385.0
Construction division [Member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	7,091.0	6,909.0	6,287.0
Toll roads division [Member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	1,236.0	1,071.0	765.0
Airports division [Member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	90.0	8.0	5.0
Corporation division [Member]
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue from contracts with customers	607.0	351.0	328.0
Completed work pending certification [Member]
Customer contract assets liabilities [Line Items]
Total customer contract balances	573.0	446.0	406.0
Increase decrease in customer contract balances exchange rate	10.0	2.0
Increase decrease in customer contract balances consolidation scope changes	0.0	0.0
Increase decrease in customer contract balances other	118.0	38.0
Retentions member [Member]
Customer contract assets liabilities [Line Items]
Total customer contract balances	191.0	160.0	141.0
Increase decrease in customer contract balances exchange rate	3.0	1.0
Increase decrease in customer contract balances consolidation scope changes	0.0	0.0
Increase decrease in customer contract balances other	28.0	18.0
Total customer contract assets [Member]
Customer contract assets liabilities [Line Items]
Total customer contract balances	764.0	606.0	547.0
Increase decrease in customer contract balances exchange rate	13.0	3.0
Increase decrease in customer contract balances consolidation scope changes	0.0	0.0
Increase decrease in customer contract balances other	146.0	56.0
Work certified in advance [Member]
Customer contract assets liabilities [Line Items]
Total customer contract balances	1,227.0	1,124.0	962.0
Increase decrease in customer contract balances exchange rate	26.0	(3.0)
Increase decrease in customer contract balances consolidation scope changes	0.0	0.0
Increase decrease in customer contract balances other	77.0	165.0
Advance payments [Member]
Customer contract assets liabilities [Line Items]
Total customer contract balances	392.0	406.0	402.0
Increase decrease in customer contract balances exchange rate	1.0	5.0
Increase decrease in customer contract balances consolidation scope changes	0.0	0.0
Increase decrease in customer contract balances other	(14.0)	(1.0)
Total customer contract liabilities [Member]
Customer contract assets liabilities [Line Items]
Total customer contract balances	1,619.0	1,530.0	€ 1,364.0
Increase decrease in customer contract balances exchange rate	27.0	2.0
Increase decrease in customer contract balances consolidation scope changes	0.0	0.0
Increase decrease in customer contract balances other	€ 63.0	€ 164.0

Customer contract assets liabilities

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- Definition

Increase decrease in customer contract balances consolidation scope changes

+ References

No definition available.

+ Details

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- Definition

Increase decrease in customer contract balances exchange rate

+ References

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- Definition

Total customer contract balances

+ References

No definition available.

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- Definition

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.

+ 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 2024-01-01
-Paragraph 114
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2024-en-r&anchor=para_114&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 15
-IssueDate 2024-01-01
-Paragraph 113
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2024-en-r&anchor=para_113_a&doctype=Standard
-URIDate 2024-03-27

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