Pensions and Other Post-employment Benefit Obligations - Summary of Sensitivity Analysis on Defined Benefit Obligations (Detail) - Actuarial assumption of discount rates [member] € in Millions	Dec. 31, 2018 EUR (€)
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Total sensitivity on Defined Benefit Obligations, increase in discount rates	€ (62)
Total sensitivity on Defined Benefit Obligations, decrease in discount rates	69
France [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Total sensitivity on Defined Benefit Obligations, increase in discount rates	(9)
Total sensitivity on Defined Benefit Obligations, decrease in discount rates	10
Germany [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Total sensitivity on Defined Benefit Obligations, increase in discount rates	(8)
Total sensitivity on Defined Benefit Obligations, decrease in discount rates	9
Switzerland [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Total sensitivity on Defined Benefit Obligations, increase in discount rates	(19)
Total sensitivity on Defined Benefit Obligations, decrease in discount rates	22
United States [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Total sensitivity on Defined Benefit Obligations, increase in discount rates	(26)
Total sensitivity on Defined Benefit Obligations, decrease in discount rates	€ 28

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- Definition

The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
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The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

+ References

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