Restructuring Plans - Restructuring Plan Costs (Details) - USD ($)	3 Months Ended			6 Months Ended	12 Months Ended		25 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Dec. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 23,000,000				$ 115,000,000	$ 131,000,000	$ 269,000,000
2018 Rigid Packaging Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	8,000,000				37,000,000	64,000,000	109,000,000
2019 Bemis Integration Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	6,000,000				60,000,000	48,000,000	115,000,000
Restructuring Related Costs		$ 1,000,000		$ 15,000,000
Other Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 9,000,000		$ 0		$ 18,000,000	$ 19,000,000	$ 45,000,000