Accumulated Other Comprehensive Income (Loss) Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		$ 0.0
Non-operating expenses	$ 1,125.0	1,026.6	$ 986.3
Tax (benefit) expense	35.4	95.6	60.2
Total reclassifications for the period, net of tax	(143.7)	(71.9)	$ (93.3)
AOCI Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	0.0	(43.5)
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Non-operating expenses	25.7	20.5
Tax (benefit) expense	(6.6)	(8.0)
Total reclassifications for the period, net of tax	19.1	12.5
Reclassification out of AOCI | Actuarial Losses Recognized
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Non-operating expenses	27.4	22.3
Tax (benefit) expense	(7.0)	(8.7)
Total reclassifications for the period, net of tax	20.4	13.6
Reclassification out of AOCI | Prior Service Costs Recognized
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Non-operating expenses	(1.7)	(1.8)
Tax (benefit) expense	0.4	0.7
Total reclassifications for the period, net of tax	$ (1.3)	$ (1.1)