Comprehensive Income (Changes in AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity Attributable to Parent	$ 38.0	$ 101.6	$ 9.0	$ 485.7
Changes in AOCI by component (net of tax) [Roll Forward]
Beginning balance	(204.7)
Other comprehensive income (loss) before reclassifications	(2.5)	(65.6)
Amounts reclassified from AOCI	12.1	14.4
Net other comprehensive income (loss)	9.6	(51.2)
Ending balance	(195.1)	(204.7)
Gains (Losses) on Cash Flow Hedges [Member]
Changes in AOCI by component (net of tax) [Roll Forward]
Beginning balance	(8.4)	(4.6)
Other comprehensive income (loss) before reclassifications	6.0	(11.9)
Amounts reclassified from AOCI	8.0	8.1
Net other comprehensive income (loss)	14.0	(3.8)
Ending balance	5.6	(8.4)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes in AOCI by component (net of tax) [Roll Forward]
Beginning balance	4.4	3.2
Other comprehensive income (loss) before reclassifications	(2.1)	1.2
Amounts reclassified from AOCI	0.0	0.0
Net other comprehensive income (loss)	(2.1)	1.2
Ending balance	2.3	4.4
Defined Benefit Plan Items [Member]
Changes in AOCI by component (net of tax) [Roll Forward]
Beginning balance	(139.3)	(149.4)
Other comprehensive income (loss) before reclassifications	5.2	3.8
Amounts reclassified from AOCI	4.1	6.3
Net other comprehensive income (loss)	9.3	10.1
Ending balance	(130.0)	(139.3)
Foreign Currency Translation Adjustments [Member]
Changes in AOCI by component (net of tax) [Roll Forward]
Beginning balance	(61.4)	(2.7)
Other comprehensive income (loss) before reclassifications	(11.6)	(58.7)
Amounts reclassified from AOCI	0.0	0.0
Net other comprehensive income (loss)	(11.6)	(58.7)
Ending balance	(73.0)	(61.4)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Stockholders' Equity Attributable to Parent	$ (195.1)	$ (204.7)	$ (153.5)	$ (61.1)