Restructuring (Textuals) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017	Aug. 15, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		$ 65.0	$ 49.4	$ 59.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Restructuring Liabilities			(8.2)	45.5
DN Now Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		58.9
DN Now Plan [Member] | Minimum
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost		175.0
DN Now Plan [Member] | Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost		200.0
Global Realigment Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		7.7
DN2020 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		6.0	47.0	42.8
Delta Program [Member] [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		3.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Restructuring Liabilities					$ 37.3	$ 45.5
Strategic Alliance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		0.1	$ 2.4	$ 5.7
Other Restructuring [Member] | Global Realigment Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		3.5
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		166.1
Severance | DN Now Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		58.9
Severance | Global Realigment Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		105.0
Severance | DN2020 Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		95.8
Severance | Delta Program [Member] [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		3.2
Severance | Strategic Alliance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		$ 8.2
Subsequent Event [Member] | DN Now Plan [Member]
Restructuring Cost and Reserve [Line Items]
Anticipated Annual Synergies	$ 160.0
Subsequent Event [Member] | Severance | DN Now Plan [Member]
Restructuring Cost and Reserve [Line Items]
Anticipated Annual Synergies	$ 130.0
Measurement Period Adjustment [Member] | Delta Program [Member] [Member]
Restructuring Cost and Reserve [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Restructuring Liabilities					$ 8.2