v3.8.0.1
Provisions - Post-Employment Defined Benefit Plans by Country of Operation (Details) - EUR (€)
€ in Millions
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) € 3 € 3  
Net provision 1,039 938  
Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 804 598  
Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 3,383 3,378 € 2,858
Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (2,579) (2,780) (2,522)
Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 232 337  
Others      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Net provision 7 8  
Others | Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 7 8  
Others | Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 16 16 15
Others | Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (9) (8) (10)
Others | Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Spain | Operating segments      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Net provision 490 533  
Spain | Operating segments | Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 490 533  
Spain | Operating segments | Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 490 533 552
Spain | Operating segments | Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Spain | Operating segments | Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
United Kingdom | Operating segments      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Net provision 177 172  
United Kingdom | Operating segments | Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 177 172  
United Kingdom | Operating segments | Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 1,828 1,834 1,613
United Kingdom | Operating segments | Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (1,651) (1,662) (1,753)
United Kingdom | Operating segments | Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Germany | Operating segments      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Net provision 151 105  
Germany | Operating segments | Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 151 105  
Germany | Operating segments | Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 235 233 198
Germany | Operating segments | Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (84) (128) (122)
Germany | Operating segments | Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Brazil | Operating segments      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 3 3  
Net provision 134 95  
Brazil | Operating segments | Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (101) (245)  
Brazil | Operating segments | Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 734 737 449
Brazil | Operating segments | Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (835) (982) (637)
Brazil | Operating segments | Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 232 337  
Hispanoamérica | Operating segments      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Net provision 80 25  
Hispanoamérica | Operating segments | Net provision before asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 80 25  
Hispanoamérica | Operating segments | Obligation      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 80 25 € 31
Hispanoamérica | Operating segments | Assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 0 0  
Hispanoamérica | Operating segments | Asset ceiling      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) € 0 € 0