Postretirement and Other Benefits - Fair Value of Plan Assets (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	$ 128.7	$ 118.9
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	128.7	118.9
Fair value of plan assets at end of year	113.1	128.7
United States \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.1	1.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.1
Fair value of plan assets at end of year	1.0	1.1
United States \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	9.0	9.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	9.0
Fair value of plan assets at end of year	5.7	9.0
United States \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	5.8	5.8
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	5.8
Fair value of plan assets at end of year	3.3	5.8
United States \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	25.3	25.3
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	25.3
Fair value of plan assets at end of year	15.5	25.3
United States \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	87.4	87.4
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	87.4
Fair value of plan assets at end of year	87.6	87.4
United States \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.1	0.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.1
Fair value of plan assets at end of year	0.0	0.1
United States \| Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	71.2	71.2
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	71.2
Fair value of plan assets at end of year	65.7	71.2
United States \| Fair Value Measured at Net Asset Value Per Share [Member] \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	9.0	9.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	9.0
Fair value of plan assets at end of year	5.7	9.0
United States \| Fair Value Measured at Net Asset Value Per Share [Member] \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	5.8	5.8
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	5.8
Fair value of plan assets at end of year	3.3	5.8
United States \| Fair Value Measured at Net Asset Value Per Share [Member] \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	25.3	25.3
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	25.3
Fair value of plan assets at end of year	15.5	25.3
United States \| Fair Value Measured at Net Asset Value Per Share [Member] \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	31.1	31.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	31.1
Fair value of plan assets at end of year	41.2	31.1
United States \| Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.1	1.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.1
Fair value of plan assets at end of year	1.0	1.1
United States \| Level 1 [Member] \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.1	1.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.1
Fair value of plan assets at end of year	1.0	1.1
United States \| Level 1 [Member] \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 1 [Member] \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 1 [Member] \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 1 [Member] \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 1 [Member] \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	56.3	56.3
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	56.3
Fair value of plan assets at end of year	46.4	56.3
United States \| Level 2 [Member] \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 2 [Member] \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 2 [Member] \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 2 [Member] \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 2 [Member] \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	56.3	56.3
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	56.3
Fair value of plan assets at end of year	46.4	56.3
United States \| Level 2 [Member] \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.1	0.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.1	0.1
Realized and unrealized gains	0.0	0.0
Purchases	0.0	0.0
Sales	(0.1)	0.0
Fair value of plan assets at end of year	0.0	0.1
United States \| Level 3 [Member] \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 3 [Member] \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 3 [Member] \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 3 [Member] \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 3 [Member] \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
United States \| Level 3 [Member] \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.1	0.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.1
Fair value of plan assets at end of year	0.0	0.1
France
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	3.2	6.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	3.2	6.1
Fair value of plan assets at end of year	2.1	3.2
France \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.2	1.2
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.2
Fair value of plan assets at end of year	0.9	1.2
France \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.0	1.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.0
Fair value of plan assets at end of year	0.6	1.0
France \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.9	0.9
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.9
Fair value of plan assets at end of year	0.5	0.9
France \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.1	0.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.1
Fair value of plan assets at end of year	0.1	0.1
France \| Level 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	2.2	2.2
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	2.2
Fair value of plan assets at end of year	1.5	2.2
France \| Level 1 [Member] \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.2	1.2
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.2
Fair value of plan assets at end of year	0.9	1.2
France \| Level 1 [Member] \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.0	1.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.0
Fair value of plan assets at end of year	0.6	1.0
France \| Level 1 [Member] \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 1 [Member] \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 1 [Member] \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 1 [Member] \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.0	1.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.0
Fair value of plan assets at end of year	0.6	1.0
France \| Level 2 [Member] \| Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 2 [Member] \| Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 2 [Member] \| Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 2 [Member] \| International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
France \| Level 2 [Member] \| Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.9	0.9
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.9
Fair value of plan assets at end of year	0.5	0.9
France \| Level 2 [Member] \| Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.1	0.1
U.S. Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.1
Fair value of plan assets at end of year	$ 0.1	$ 0.1

Postretirement and Other Benefits - Fair Value of Plan Assets (Details) - Pension Benefits - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

United States

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Fair value of plan assets

$ 128.7

$ 118.9

U.S. Level 3 Asset Reconciliation

Fair value of plan assets at beginning of year

128.7