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Operating Segment Information - Additional Information (Detail) € in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 EUR (€) Employees Facility | Dec. 31, 2017 EUR (€) | Dec. 31, 2016 EUR (€)
Disclosure of operating segments [line items] |  |  |
Number of employees | Employees | 13,000 |  |
Revenue | € 5,686 | € 5,237 | € 4,743
Information about major customers | No other single customer contributed 10% or more to the Group's revenue for 2018, 2017 and 2016. |  |
P&ARP [member] |  |  |
Disclosure of operating segments [line items] |  |  |
Number of facilities | Facility | 4 |  |
Number of employees | Employees | 3,800 |  |
Revenue | € 3,050 | 2,805 | 2,482
P&ARP [member] | Two largest customers [member] |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | € 812 | 1,364 | 1,220
A&T [member] |  |  |
Disclosure of operating segments [line items] |  |  |
Number of facilities | Facility | 6 |  |
Number of employees | Employees | 4,000 |  |
Revenue | € 1,339 | 1,301 | 1,279
AS&I [member] |  |  |
Disclosure of operating segments [line items] |  |  |
Number of facilities | Facility | 16 |  |
Number of employees | Employees | 4,500 |  |
Revenue | € 1,287 | € 1,118 | € 993

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