Summary of Significant Accounting Policies (PPE Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Capitalized Interest Costs
Interest Costs Incurred	$ 135.1	$ 156.3	$ 185.2
Interest Costs Capitalized in PPE	0.5	0.8	2.1
Depreciation [Abstract]
Depreciation	92.4	98.1	130.0
Capitalized Computer Software [Abstract]
Capitalized Computer Software, Gross	42.5	42.6
Capitalized computer software accumulated depreciation	23.1	15.7
Assets under finance leases
Depreciation [Abstract]
Depreciation	$ 1.4	2.3	3.9
Capitalized computer software
Capitalized Computer Software [Abstract]
Property, Plant and Equipment, Useful Life	5 years
Amortization expense	$ 7.4	$ 8.0	$ 3.3

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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For each balance sheet presented, the amount of accumulated amortization for capitalized computer software costs.

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Amount before accumulated amortization of capitalized costs for computer software, including but not limited to, acquired and internally developed computer software.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount of interest costs capitalized disclosed as an adjusting item to interest costs incurred.

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Total interest costs incurred during the period and either capitalized or charged against earnings.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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