Property, Plant and Equipment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property, plant and equipment
Property, plant and equipment, gross	$ 7,182		$ 7,182		$ 7,386
Accumulated depreciation	(2,674)		(2,674)		(2,776)
Net property, plant and equipment	4,508		4,508		4,610
Depreciation expense	121	$ 113	375	$ 373
Noncash capital expenditures			98		124
Land
Property, plant and equipment
Property, plant and equipment, gross	171		171		172
Buildings
Property, plant and equipment
Property, plant and equipment, gross	1,324		1,324		1,390
Machinery and equipment
Property, plant and equipment
Property, plant and equipment, gross	5,120		5,120		5,282
Construction-in-progress
Property, plant and equipment
Property, plant and equipment, gross	$ 567		$ 567		$ 542
Rexam
Property, plant and equipment
Catch up depreciation		$ 19