Goodwill and Other Assets Schedule of Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 1,021.7	$ 1,033.8
Accumulated amortization	(432.9)	(409.2)
Net carrying amount	$ 588.8	624.6
Internally-developed software [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year 4 months
Gross carrying amount	$ 192.5	189.6
Accumulated amortization	(126.2)	(118.9)
Net carrying amount	$ 66.3	70.7
Development costs non-software [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year 7 months
Gross carrying amount	$ 51.5	52.5
Accumulated amortization	(43.0)	(44.3)
Net carrying amount	$ 8.5	8.2
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 5 months
Gross carrying amount	$ 698.8	712.2
Accumulated amortization	(194.2)	(179.1)
Net carrying amount	$ 504.6	533.1
Other intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 months
Gross carrying amount	$ 78.9	79.5
Accumulated amortization	(69.5)	(66.9)
Net carrying amount	9.4	12.6
Other intangible asset, net [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	322.9	321.6
Accumulated amortization	(238.7)	(230.1)
Net carrying amount	$ 84.2	$ 91.5