Business Segment Information Business Segment Information (Restructuring Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Restructuring Charges	$ 34.0	$ 42.0	$ 60.0	$ 66.0
Restructuring Reserve	157.0	57.0	157.0	57.0	$ 123.0	$ 97.0	$ 115.0	$ 91.0
Payments for Restructuring	0.0	100.0	0.0	100.0
Employee Retention and Severances Expenses and Other Benefits-Related Costs [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	34.0	42.0	60.0	66.0
Restructuring Reserve	143.0	36.0	143.0	36.0	109.0	83.0	94.0	70.0
Payments for Restructuring	0.0	100.0	0.0	100.0
Economic Development Costs [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	0.0	0.0	0.0	0.0
Restructuring Reserve	14.0	21.0	14.0	21.0	$ 14.0	$ 14.0	$ 21.0	$ 21.0
Payments for Restructuring	$ 0.0	$ 0.0	$ 0.0	$ 0.0