v3.26.1
Risk management - Schedule of exposure and impairment losses by stage, by entity (Details)
€ in Millions
Dec. 31, 2025
EUR (€)
tranches
Dec. 31, 2024
EUR (€)
Dec. 31, 2023
EUR (€)
Dec. 31, 2022
EUR (€)
Disclosure of credit risk exposure [line items]        
Number of tranches | tranches 4      
Maximum exposure to credit risk € 888,496 € 908,963 € 914,491  
Financial assets (300,026) (283,497) (243,203)  
Customers        
Disclosure of credit risk exposure [line items]        
Financial assets (1,037,288) (1,054,069) (1,036,349)  
Accumulated impairment        
Disclosure of credit risk exposure [line items]        
Financial assets 520 349 286  
Accumulated impairment | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 21,158 22,125 22,788  
Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 21,158 22,125 22,788 € 22,684
Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets € 21,158 22,125 22,788 22,684
Spain        
Disclosure of credit risk exposure [line items]        
Number of tranches | tranches 4      
Maximum exposure to credit risk € 201,013 198,936 205,994  
Spain | Accumulated impairment        
Disclosure of credit risk exposure [line items]        
Financial assets 1,086      
Spain | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 3,069 3,863 3,922  
Financial instruments not credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 7,631 8,037 8,550  
Financial instruments credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 13,527 14,088 14,238  
Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 779,109 800,360 807,228  
Stage 1 | Financial instruments not credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 3,000 3,293 3,596 3,626
Stage 1 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 183,686 179,041 183,324  
Stage 1 | Financial instruments not credit-impaired | Spain | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 382 340 300  
Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 78,112 77,330 74,808  
Stage 2 and 3 | Financial instruments not credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 4,631 4,744 4,954 5,127
Stage 2 and 3 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 11,566 13,277 15,134  
Stage 2 and 3 | Financial instruments not credit-impaired | Spain | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 483 570 663  
Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 31,275 31,273 32,455  
Stage 2 and 3 | Financial instruments credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 13,527 14,088 14,238 € 13,931
Stage 2 and 3 | Financial instruments credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 5,761 6,618 7,536  
Stage 2 and 3 | Financial instruments credit-impaired | Spain | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 2,204 2,953 2,959  
From AAA to AA-        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 115,038 104,958 143,029  
From AAA to AA- | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 35,578 35,457 46,875  
From AAA to AA- | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 112,795 102,394 140,792  
From AAA to AA- | Stage 1 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 35,407 35,347 46,827  
From AAA to AA- | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 2,243 2,564 2,237  
From AAA to AA- | Stage 2 and 3 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 171 110 48  
From AAA to AA- | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
From AAA to AA- | Stage 2 and 3 | Financial instruments credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0  
From A+ to BB        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 381,579 426,837 417,930  
From A+ to BB | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 110,454 105,321 101,859  
From A+ to BB | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 367,186 411,158 404,184  
From A+ to BB | Stage 1 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 109,001 104,197 101,079  
From A+ to BB | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 14,393 15,678 13,746  
From A+ to BB | Stage 2 and 3 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,453 1,124 780  
From A+ to BB | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
From A+ to BB | Stage 2 and 3 | Financial instruments credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0  
From BB- to B-        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 335,376 318,878 290,599  
From BB- to B- | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 45,351 46,257 43,694  
From BB- to B- | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 291,014 276,422 250,619  
From BB- to B- | Stage 1 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 37,089 37,413 33,905  
From BB- to B- | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 44,363 42,456 39,979  
From BB- to B- | Stage 2 and 3 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 8,262 8,844 9,789  
From BB- to B- | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
From BB- to B- | Stage 2 and 3 | Financial instruments credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0  
CCC and below        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 56,503 58,291 62,933  
CCC and below | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 9,630 11,901 13,566  
CCC and below | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 8,114 10,385 11,633  
CCC and below | Stage 1 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 2,189 2,084 1,513  
CCC and below | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 17,114 16,633 18,846  
CCC and below | Stage 2 and 3 | Financial instruments not credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,680 3,199 4,517  
CCC and below | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 31,275 31,273 32,455  
CCC and below | Stage 2 and 3 | Financial instruments credit-impaired | Spain        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk € 5,761 6,618 7,536  
Santander UK plc        
Disclosure of credit risk exposure [line items]        
Number of tranches | tranches 4      
Maximum exposure to credit risk € 222,346 236,850 235,344  
Santander UK plc | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 855 967 1,066  
Santander UK plc | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 200,576 209,588 205,708  
Santander UK plc | Stage 1 | Financial instruments not credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 163 166 172  
Santander UK plc | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 19,295 23,970 26,118  
Santander UK plc | Stage 2 and 3 | Financial instruments not credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 319 401 498  
Santander UK plc | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 2,475 3,292 3,518  
Santander UK plc | Stage 2 and 3 | Financial instruments credit-impaired | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 373 400 396  
Santander UK plc | From AAA to AA-        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 30,344 33,196 47,509  
Santander UK plc | From AAA to AA- | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 29,963 32,012 46,236  
Santander UK plc | From AAA to AA- | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 381 1,184 1,273  
Santander UK plc | From AAA to AA- | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander UK plc | From A+ to BB        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 162,510 170,886 156,734  
Santander UK plc | From A+ to BB | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 152,981 159,970 145,884  
Santander UK plc | From A+ to BB | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 9,529 10,916 10,850  
Santander UK plc | From A+ to BB | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander UK plc | From BB- to B-        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 26,400 28,769 27,583  
Santander UK plc | From BB- to B- | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 17,630 17,594 13,588  
Santander UK plc | From BB- to B- | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 8,770 11,175 13,995  
Santander UK plc | From BB- to B- | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander UK plc | CCC and below        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 3,092 3,999 3,518  
Santander UK plc | CCC and below | Stage 1 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 2 12 0  
Santander UK plc | CCC and below | Stage 2 and 3 | Financial instruments not credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 615 695 0  
Santander UK plc | CCC and below | Stage 2 and 3 | Financial instruments credit-impaired        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk € 2,475 3,292 3,518  
Santander Bank, National Association | US        
Disclosure of credit risk exposure [line items]        
Number of tranches | tranches 4      
Santander Bank, National Association | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk € 45,741 54,243 55,984  
Santander Bank, National Association | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 804 838 885  
Santander Bank, National Association | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 38,511 47,569 50,666  
Santander Bank, National Association | Stage 1 | Financial instruments not credit-impaired | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 277 292 409  
Santander Bank, National Association | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 6,072 5,544 4,424  
Santander Bank, National Association | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 325 364 335  
Santander Bank, National Association | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,158 1,130 894  
Santander Bank, National Association | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income        
Disclosure of credit risk exposure [line items]        
Financial assets 202 182 141  
Santander Bank, National Association | From AAA to AA- | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,646 4,492 4,910  
Santander Bank, National Association | From AAA to AA- | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,622 4,215 4,834  
Santander Bank, National Association | From AAA to AA- | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 24 277 76  
Santander Bank, National Association | From AAA to AA- | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Bank, National Association | From A+ to BB | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 8,080 22,352 20,927  
Santander Bank, National Association | From A+ to BB | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 7,352 21,422 20,468  
Santander Bank, National Association | From A+ to BB | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 728 930 459  
Santander Bank, National Association | From A+ to BB | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Bank, National Association | From BB- to B- | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 33,217 25,754 28,751  
Santander Bank, National Association | From BB- to B- | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 28,758 21,899 25,312  
Santander Bank, National Association | From BB- to B- | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 4,459 3,855 3,439  
Santander Bank, National Association | From BB- to B- | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Bank, National Association | CCC and below | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 2,798 1,645 1,396  
Santander Bank, National Association | CCC and below | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 779 33 52  
Santander Bank, National Association | CCC and below | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 861 482 450  
Santander Bank, National Association | CCC and below | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk € 1,158 1,130 894  
Santander Consumer USA Holdings Inc. | US | Total North America        
Disclosure of credit risk exposure [line items]        
Number of tranches | tranches 4      
Maximum exposure to credit risk € 25,204 30,669 28,877  
Santander Consumer USA Holdings Inc. | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 3,017 3,544 3,328  
Santander Consumer USA Holdings Inc. | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 13,798 20,263 18,973  
Santander Consumer USA Holdings Inc. | Stage 1 | Financial instruments not credit-impaired | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 419 630 597  
Santander Consumer USA Holdings Inc. | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 5,818 4,677 4,632  
Santander Consumer USA Holdings Inc. | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 910 1,006 1,019  
Santander Consumer USA Holdings Inc. | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 5,588 5,729 5,272  
Santander Consumer USA Holdings Inc. | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 1,688 1,908 1,712  
Santander Consumer USA Holdings Inc. | From AAA to AA- | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | From AAA to AA- | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | From AAA to AA- | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | From AAA to AA- | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | From A+ to BB | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 54 202 99  
Santander Consumer USA Holdings Inc. | From A+ to BB | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 54 202 99  
Santander Consumer USA Holdings Inc. | From A+ to BB | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | From A+ to BB | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | From BB- to B- | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 11,114 13,253 12,515  
Santander Consumer USA Holdings Inc. | From BB- to B- | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 10,167 12,802 12,120  
Santander Consumer USA Holdings Inc. | From BB- to B- | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 947 451 395  
Santander Consumer USA Holdings Inc. | From BB- to B- | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Santander Consumer USA Holdings Inc. | CCC and below | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 14,036 17,214 16,263  
Santander Consumer USA Holdings Inc. | CCC and below | Stage 1 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 3,577 7,259 6,754  
Santander Consumer USA Holdings Inc. | CCC and below | Stage 2 and 3 | Financial instruments not credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 4,871 4,226 4,237  
Santander Consumer USA Holdings Inc. | CCC and below | Stage 2 and 3 | Financial instruments credit-impaired | US | Total North America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk € 5,588 5,729 5,272  
Banco Santander (Brasil) S.A. | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Number of tranches | tranches 4      
Maximum exposure to credit risk € 104,136 103,541 113,409  
Banco Santander (Brasil) S.A. | Brazil | Total South America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 5,992 5,313 6,338  
Banco Santander (Brasil) S.A. | Stage 1 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 83,383 86,459 96,799  
Banco Santander (Brasil) S.A. | Stage 1 | Financial instruments not credit-impaired | Brazil | Total South America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 648 687 722  
Banco Santander (Brasil) S.A. | Stage 2 and 3 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 13,602 10,700 9,131  
Banco Santander (Brasil) S.A. | Stage 2 and 3 | Financial instruments not credit-impaired | Brazil | Total South America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 1,128 860 1,078  
Banco Santander (Brasil) S.A. | Stage 2 and 3 | Financial instruments credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 7,151 6,382 7,479  
Banco Santander (Brasil) S.A. | Stage 2 and 3 | Financial instruments credit-impaired | Brazil | Total South America | Accumulated impairment | Financial assets at amortised cost and financial assets at fair value through other comprehensive income | Customers        
Disclosure of credit risk exposure [line items]        
Financial assets 4,216 3,766 4,538  
Banco Santander (Brasil) S.A. | From AAA to AA- | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 18,411 20,527 21,138  
Banco Santander (Brasil) S.A. | From AAA to AA- | Stage 1 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 16,898 19,557 20,670  
Banco Santander (Brasil) S.A. | From AAA to AA- | Stage 2 and 3 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,513 970 468  
Banco Santander (Brasil) S.A. | From AAA to AA- | Stage 2 and 3 | Financial instruments credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Banco Santander (Brasil) S.A. | From A+ to BB | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 30,432 34,461 39,620  
Banco Santander (Brasil) S.A. | From A+ to BB | Stage 1 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 29,179 32,824 38,869  
Banco Santander (Brasil) S.A. | From A+ to BB | Stage 2 and 3 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,253 1,637 751  
Banco Santander (Brasil) S.A. | From A+ to BB | Stage 2 and 3 | Financial instruments credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Banco Santander (Brasil) S.A. | From BB- to B- | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 43,124 38,940 40,284  
Banco Santander (Brasil) S.A. | From BB- to B- | Stage 1 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 36,089 33,655 36,107  
Banco Santander (Brasil) S.A. | From BB- to B- | Stage 2 and 3 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 7,035 5,285 4,177  
Banco Santander (Brasil) S.A. | From BB- to B- | Stage 2 and 3 | Financial instruments credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 0 0 0  
Banco Santander (Brasil) S.A. | CCC and below | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 12,169 9,613 12,367  
Banco Santander (Brasil) S.A. | CCC and below | Stage 1 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 1,217 423 1,153  
Banco Santander (Brasil) S.A. | CCC and below | Stage 2 and 3 | Financial instruments not credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk 3,801 2,808 3,735  
Banco Santander (Brasil) S.A. | CCC and below | Stage 2 and 3 | Financial instruments credit-impaired | Brazil | Total South America        
Disclosure of credit risk exposure [line items]        
Maximum exposure to credit risk € 7,151 € 6,382 € 7,479