INVESTMENTS (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [line items]
Investments at 1 January	$ 9
Investments at 31 December	10	$ 9
Fair value through OCI
Disclosure of detailed information about financial instruments [line items]
Investments at 1 January	9	7
Additions	2	2
Fair value remeasurement	(1)
Investments at 31 December	$ 10	$ 9

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfFinancialInstrumentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The gains (losses) recognised in other comprehensive income on remeasuring available-for-sale financial assets, before tax, before reclassification adjustments. [Refer: Financial assets available-for-sale]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2023-01-01
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 91
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2017-en-b&anchor=para_91_b&doctype=Standard&forcepdf=true
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2023-01-01
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 20
-Subparagraph a
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_20_a_ii&doctype=Standard&book=b
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_GainsLossesOnRemeasuringAvailableforsaleFinancialAssetsBeforeTax
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of non-current financial assets available-for-sale. [Refer: Financial assets available-for-sale; Non-current financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2023-01-01
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 8
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_8_d&doctype=Standard&book=b
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_NoncurrentFinancialAssetsAvailableforsale
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the fair value of additions to available for sale securities, including purchases, transfers and other additions, for the period.

+ References

No definition available.

+ Details

Name:	snn_AdditionsToAvailableForSaleSecuritiesFairValue
Namespace Prefix:	snn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_CategoriesOfFinancialAssetsAxis=ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: