Subsequent events (Details) - 2018 Footprint Realignment Plan - Subsequent Event $ in Millions	May 01, 2018 USD ($)
Minimum
Subsequent Event [Line Items]
Restructuring costs expected cash payment	$ 99
Expected capital expenditures	19
Maximum
Subsequent Event [Line Items]
Restructuring costs expected cash payment	127
Expected capital expenditures	$ 23