Shareowners' Deficit Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		$ (171.0)	$ (173.9)
Remeasurement of benefit obligations		6.6	(6.6)	$ (45.4)
Reclassifications, net		6.0	9.5
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax		68.1	0.0	0.0
Ending balance		(90.3)	(171.0)	(173.9)
Accumulated Translation Adjustment [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		(0.7)	(0.3)
Remeasurement of benefit obligations		0.0	0.0
Reclassifications, net		(0.1)	(0.4)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax		0.0
Ending balance		(0.8)	(0.7)	(0.3)
Accumulated Defined Benefit Plans Adjustment [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		(170.3)	(173.6)
Remeasurement of benefit obligations		6.6	(6.6)
Reclassifications, net	[1]	6.1	9.9
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax		0.0
Ending balance		(157.6)	(170.3)	(173.6)
CyrusOne [Member]
Changes in Accumulated Other Comprehensive Loss by Component [Roll Forward]
Beginning balance		0.0	0.0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		0.0	0.0
Reclassifications, net		0.0	0.0
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	[2]	68.1
Ending balance		$ 68.1	$ 0.0	$ 0.0

[1] These reclassifications are included in the components of net period pension and postretirement benefit costs (see Note 9 for additional details). The components of net period pension and postretirement benefit cost are reported within "Cost of services", "Cost of products sold", and "Selling, general and administrative" expenses on the Consolidated Statements of Operations.

[2] The unrealized gain on the investment in CyrusOne was recorded in 2016 as the investment is no longer accounted for using the equity-method and is recorded as an available-for-sale security on the Consolidated Balance Sheets at fair value.