Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Beginning Balance	$ (144.0)	$ (135.0)	$ (122.0)	$ (146.0)	$ (122.0)
Effect of adoption of ASU 2018-02					(17.0)
Other comprehensive income (loss) before reclassifications	1.0	(14.0)		2.0	(11.0)
Other Comprehensive Income (Loss) before Reclassifications, Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	1.0	(14.0)		2.0	(11.0)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1.0	2.0		3.0	3.0
Reclassification from AOCI, Current Period, Tax	0.0	(0.0)		(1.0)	(1.0)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1.0	1.0		2.0	3.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	2.0	(12.0)		4.0	(9.0)
Ending Balance	(143.0)	(147.0)	(135.0)	(143.0)	(147.0)
Foreign currency translation adjustments
Beginning Balance	(55.0)	(37.0)	(40.0)	(57.0)	(40.0)
Other comprehensive income (loss) before reclassifications	1.0	(14.0)		3.0	(12.0)
Other Comprehensive Income (Loss) before Reclassifications, Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	1.0	(14.0)		3.0	(12.0)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.0	0.0		0.0	0.0
Reclassification from AOCI, Current Period, Tax	0.0	0.0		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1.0	(14.0)		3.0	(12.0)
Ending Balance	(54.0)	(51.0)	(37.0)	(54.0)	(51.0)
Actuarial loss, net of tax
Beginning Balance	(87.0)	(96.0)	(80.0)	(88.0)	(80.0)
Effect of adoption of ASU 2018-02					(17.0)
Other comprehensive income (loss) before reclassifications	(0.0)	0.0		0.0	0.0
Other Comprehensive Income (Loss) before Reclassifications, Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(0.0)	0.0		(0.0)	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1.0	2.0		2.0	3.0
Reclassification from AOCI, Current Period, Tax	(0.0)	(0.0)		(1.0)	(1.0)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1.0	1.0		2.0	2.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1.0	1.0		2.0	3.0
Ending Balance	(87.0)	(94.0)	(96.0)	(87.0)	(94.0)
Prior service cost, net of tax
Beginning Balance	(4.0)	(5.0)	(5.0)	(5.0)	(5.0)
Other comprehensive income (loss) before reclassifications	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss) before Reclassifications, Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0.0	0.0		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.0	0.0		0.0	0.0
Reclassification from AOCI, Current Period, Tax	0.0	0.0		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0.0	0.0		0.0	0.0
Ending Balance	(4.0)	(5.0)	(5.0)	(4.0)	(5.0)
Unrealized gain (loss) on investments
Beginning Balance	4.0	4.0	4.0	4.0	4.0
Effect of adoption of ASU 2018-02					1.0
Other comprehensive income (loss) before reclassifications	(0.0)	(0.0)		(1.0)	0.0
Other Comprehensive Income (Loss) before Reclassifications, Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(0.0)	(0.0)		(1.0)	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.0	0.0		0.0	0.0
Reclassification from AOCI, Current Period, Tax	0.0	0.0		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(0.0)	(0.0)		(1.0)	0.0
Ending Balance	4.0	4.0	4.0	4.0	4.0
Other
Beginning Balance	(1.0)	(2.0)	(2.0)	(1.0)	(2.0)
Other comprehensive income (loss) before reclassifications	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss) before Reclassifications, Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0.0	0.0		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.0	0.0		0.0	0.0
Reclassification from AOCI, Current Period, Tax	0.0	0.0		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.0	0.0		0.0	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0.0	0.0		0.0	0.0
Ending Balance	(1.0)	(1.0)	(2.0)	(1.0)	(1.0)
AOCI Attributable to Parent [Member]
Beginning Balance	(144.0)	(135.0)	(122.0)	(146.0)	(122.0)
Ending Balance	$ (143.0)	$ (147.0)	(135.0)	$ (143.0)	$ (147.0)
Accounting Standards Update 2018-02 [Member]
Effect of adoption of ASU 2018-02			0.0
Accounting Standards Update 2018-02 [Member] \| AOCI Attributable to Parent [Member]
Effect of adoption of ASU 2018-02			$ (17.0)

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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