Asset Impairment, Exit and Implementation Costs (Narrative) (Details) - USD ($)	1 Months Ended	3 Months Ended
	Dec. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Restructuring Cost and Reserve [Line Items]
Charges		$ 40,000,000
Restructuring charges		49,000,000	$ 3,000,000
Payments for restructuring		35,000,000
Cost Reduction Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 210,000,000
Charges		182,000,000
Restructuring charges	121,000,000
Payments for restructuring	$ 0	22,000,000
Employee Severance [Member] | Cost Reduction Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost		180,000,000
Other Restructuring [Member] | Cost Reduction Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost		$ 30,000,000