Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 16.0	$ 163.0	$ 42.0	$ 254.0
Other comprehensive income (loss)
Foreign currency translation adjustments	1.0	(14.0)	3.0	(12.0)
Defined benefit pension plans:
Amortization of amounts included in net periodic benefit cost, net of tax	1.0	1.0	2.0	3.0
Other comprehensive income (loss)	2.0	(12.0)	4.0	(9.0)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	17.0	150.0	46.0	245.0
Net loss attributable to redeemable noncontrolling interest	(2.0)	0.0	(2.0)	0.0
Comprehensive income	19.0	150.0	48.0	245.0
Actuarial loss, net of tax
Defined benefit pension plans:
Change benefit obligations, translation adjustment	(0.0)	0.0	(0.0)	0.0
Amortization of amounts included in net periodic benefit cost, net of tax	1.0	1.0	2.0	2.0
Other comprehensive income (loss)	1.0	1.0	2.0	3.0
Prior service cost, net of tax
Defined benefit pension plans:
Amortization of amounts included in net periodic benefit cost, net of tax	0.0	0.0	0.0	0.0
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Other
Defined benefit pension plans:
Amortization of amounts included in net periodic benefit cost, net of tax	0.0	0.0	0.0	0.0
Other comprehensive income (loss)	$ 0.0	$ 0.0	$ 0.0	$ 0.0