Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		$ (1,133.8)	$ (1,027.8)	$ (1,093.7)
OCI before reclassifications		(136.9)	(132.5)	10.1
Amounts reclassified from AOCI		69.0	26.5	55.8
Net current-period OCI		(67.9)	(106.0)	65.9
Ending balance	$ (1,201.7)	(1,201.7)	(1,133.8)	(1,027.8)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		11.1	17.3	9.7
OCI before reclassifications		(1.3)	(6.2)	7.6
Amounts reclassified from AOCI		0.0	0.0	0.0
Net current-period OCI		(1.3)	(6.2)	7.6
Ending balance	9.8	9.8	11.1	17.3
Tax expense for the recognition of a stranded deferred tax balance arising from deferred tax valuation allowances that was associated with a cash flow hedge portfolio	6.0
Post- retirement benefit plans [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(1,005.8)	(954.5)	(965.5)
OCI before reclassifications		(141.6)	(107.2)	(32.5)
Amounts reclassified from AOCI		64.3	55.9	43.5
Net current-period OCI		(77.3)	(51.3)	11.0
Ending balance	(1,083.1)	(1,083.1)	(1,005.8)	(954.5)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		0.0	0.0	0.0
OCI before reclassifications		0.0	0.0	0.0
Amounts reclassified from AOCI		0.0	0.0	0.0
Net current-period OCI		0.0	0.0	0.0
Ending balance	0.0	0.0	0.0	0.0
Currency translation adjustment [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(73.9)	(53.5)	(85.0)
OCI before reclassifications		(2.7)	(20.4)	31.5
Amounts reclassified from AOCI		0.0	0.0	0.0
Net current-period OCI		(2.7)	(20.4)	31.5
Ending balance	(76.6)	(76.6)	(73.9)	(53.5)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		11.1	17.3	9.7
OCI before reclassifications		(1.3)	(6.2)	7.6
Amounts reclassified from AOCI		0.0	0.0	0.0
Net current-period OCI		(1.3)	(6.2)	7.6
Ending balance	9.8	9.8	11.1	17.3
Derivatives [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(4.8)	9.0	2.4
OCI before reclassifications		7.4	(4.9)	11.1
Amounts reclassified from AOCI		(3.1)	(8.9)	(4.5)
Net current-period OCI		4.3	(13.8)	6.6
Ending balance	(0.5)	(0.5)	(4.8)	9.0
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		0.0	0.0	0.0
OCI before reclassifications		0.0	0.0	0.0
Amounts reclassified from AOCI		0.0	0.0	0.0
Net current-period OCI		0.0	0.0	0.0
Ending balance	0.0	0.0	0.0	0.0
Accumulated Deferred Tax Asset Valuation Allowance
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(49.3)	(28.8)	(45.6)
OCI before reclassifications		0.0	0.0	0.0
Amounts reclassified from AOCI		7.8	(20.5)	16.8
Net current-period OCI		7.8	(20.5)	16.8
Ending balance	(41.5)	(41.5)	(49.3)	(28.8)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		0.0	0.0	0.0
OCI before reclassifications		0.0	0.0	0.0
Amounts reclassified from AOCI		0.0	0.0	0.0
Net current-period OCI		0.0	0.0	0.0
Ending balance	$ 0.0	$ 0.0	$ 0.0	$ 0.0

Accumulated Other Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest

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Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]

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Other Comprehensive Income (Loss), before Reclassifications, Net of Tax, Attributable to Noncontrolling Interest

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Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax, Attributable to Noncontrolling Interest

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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