Inventories (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory [Line Items]
Percentage of total inventories on LIFO	66.00%	79.00%	78.00%
Excess of FIFO over LIFO	$ 286,961	$ 253,353	$ 251,060
(Decrease) increase in net income due to LIFO	$ (20,669)	$ (1,421)	$ 49,658
(Decrease) increase in net income per common share due to LIFO (in dollars per share)	$ (0.22)	$ (0.02)	$ 0.53
Valspar
Inventory [Line Items]
Percentage of total inventories on LIFO	40.00%

Increase decrease in net income per common share due to LIFO.

No definition available.

Name:	shw_IncreaseDecreaseInNetIncomePerCommonShareDueToLifo
Namespace Prefix:	shw_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount by which inventory stated at last-in first-out (LIFO) is less than (in excess of) inventory stated at other inventory cost methods.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The difference between the change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods and any LIFO decrement which have been reflected in the statement of income during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=shw_ValsparCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: