Basis of Presentation Basis of Presentation (Details)	Sep. 30, 2018
Amcor shareholders percentage ownership post transaction [Member]
Shareholders Percentage Ownership Post Transaction [Line Items]
shareholders percentage ownership	0.71
Bemis shareholders percentage ownership post transaction [Member]
Shareholders Percentage Ownership Post Transaction [Line Items]
shareholders percentage ownership	0.29

[Line Items] for Shareholders Percentage Ownership Post Transaction [Table]

No definition available.

Name:	bms_ShareholdersPercentageOwnershipPostTransactionLineItems
Namespace Prefix:	bms_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration