Pension plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Pension Cost (Reversal of Cost)		$ 45,000,000	$ 32,100,000	$ 41,200,000
Defined Contribution Plan, Employer Matching Contribution on Pre-tax Dollar for First Four Percentage of Participants Contribution			0.50
Employee contribution for the first four percent of the plan			1.00
Employer's matching contribution on each pre-tax dollar for the next four percent of participant's contribution			0.25
Participant's contribution for the next four percent to the plan			$ 1.00
Next percentage of participant contributions eligible for employer contribution match towards defined contribution plan			4.00%
Defined Contribution Plan Employer Matching Contribution		1.00
Defined Contribution Plan Employee Contribution		$ 1.00
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	7.00%	8.00%
Settlement loss (gain)		$ 10,600,000	$ 6,100,000	100,000
Plan settlements		41,600,000	26,300,000
Amount contributed to defined benefit multiemployear plans			0	100,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefits earned during the period		7,400,000	7,600,000	7,800,000
Interest cost on benefit obligation		30,200,000	32,700,000	32,600,000
Expected return on plan assets		(48,300,000)	(51,400,000)	(50,700,000)
Settlement loss (gain)		10,100,000	0	0
Curtailment gain		(300,000)	0	0
Amortization of unrecognized transition obligation		0	0	100,000
Amortization of prior service cost		900,000	800,000	900,000
Recognized actuarial net (gain) or loss		14,100,000	14,600,000	20,100,000
Net periodic benefit (income) cost		14,600,000	10,400,000	10,900,000
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement loss (gain)			5,800,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid			18,100,000
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Year Four		200,000
Interest cost on benefit obligation		200,000	200,000	300,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid		900,000	1,000,000
Amortization of prior service cost		(300,000)	(300,000)	0
Recognized actuarial net (gain) or loss		(800,000)	(700,000)	(300,000)
Net periodic benefit (income) cost		(900,000)	(800,000)	0
Defined Contribution Plans 401K Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution benefits plans		28,400,000	10,600,000	10,200,000
Bemis Investment Profit Sharing Plan and Other Defined Contribution Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution benefits plans		2,000,000	11,100,000	$ 20,000,000
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Year Four		43,100,000
Service cost - benefits earned during the period		3,800,000	6,200,000
Interest cost on benefit obligation		28,400,000	30,700,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid		79,600,000	79,400,000
Plan curtailments		$ 0	$ 0