Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net (loss) income	$ (8.3)	$ 60.6
Other comprehensive income (loss), net of tax:
Unrealized gains on Investment in CyrusOne, net of tax of $4.4	0.0	8.3
Reclassification adjustment for gain on sale of Investment in CyrusOne included in net income, net of tax of ($41.3)	0.0	(76.4)
Foreign currency translation loss	(1.8)	0.0
Defined benefit plans:
Amortization of prior service benefits included in net income, net of tax of ($0.2), ($0.4)	(0.6)	(0.7)
Amortization of net actuarial loss included in net income, net of tax of $1.2, $2.0	4.1	3.5
Total other comprehensive income (loss)	1.7	(65.3)
Total comprehensive loss	$ (6.6)	$ (4.7)