RISK MANAGEMENT (Details 14) - USD [Member] $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($) Number
Disclosure of detailed information about financial instruments [line items]
Derivative Instruments (adjusted to market)	$ 401
Deposits	239
Loans	25,459
Financial investments	0
Total Exposure	$ 26,099
Credit Risk [Member] \| Foreign Derivative Contracts [Member] \| Banco Santander Spain [Member] \| Spain
Disclosure of detailed information about financial instruments [line items]
Classification \| Number	1
Derivative Instruments (adjusted to market)	$ 974
Deposits	11,826
Loans
Financial investments
Total Exposure	$ 12,800

The amount of exposure to loss resulting from credit risk. [Refer: Credit risk [member]]

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-Note Expiry date 2021-01-01
-Name IFRS
-Number 7
-IssueDate 2018-01-01
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-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Note Expiry date 2021-01-01
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-URIDate 2018-03-16

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Note Expiry date 2021-01-01
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-URIDate 2018-03-16

Name:	ifrs-full_CreditExposure
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant