Other Assets (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months			$ 128.0
Goodwill, Purchase Accounting Adjustments				$ (2.9)
Gross Carrying Amount			1,033.8	1,074.2
Accumulated Amortization			(409.2)	(300.4)
Net Carrying Amount			624.6	773.8
Amortization expense on capitalized software			33.7	34.6	$ 24.4
Impairment of assets	$ 134.4	$ 83.1	217.5	3.1	9.8
Amortization			153.4	159.3	$ 73.0
Finite-Lived Intangible Assets, Amortization Expense, Year Two			108.8
Finite-Lived Intangible Assets, Amortization Expense, Year Three			96.2
Finite-Lived Intangible Assets, Amortization Expense, Year Four			92.0
Finite-Lived Intangible Assets, Amortization Expense, Year Five			88.6
Finite-Lived Intangible Assets, Net			513.6
Software and Software Development Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			189.6	192.9
Accumulated Amortization			(118.9)	(99.8)
Net Carrying Amount			$ 70.7	93.1
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			1 year 7 months
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 52.5	55.3
Accumulated Amortization			(44.3)	(35.1)
Net Carrying Amount			$ 8.2	20.2
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			11 months
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 712.2	741.5
Accumulated Amortization			(179.1)	(108.2)
Net Carrying Amount			$ 533.1	633.3
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			6 years 8 months
Other intangible assets, net
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 79.5	84.5
Accumulated Amortization			(66.9)	(57.3)
Net Carrying Amount			$ 12.6	27.2
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			8 months
Other intangible asset, net [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 321.6	332.7
Accumulated Amortization			(230.1)	(192.2)
Net Carrying Amount			$ 91.5	$ 140.5