Postretirement and Other Benefits - Fair Value of Plan Assets (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	$ 113.1	$ 113.1
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	113.1	128.7
Fair value of plan assets at end of year	125.8	113.1
United States | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.0	1.0
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.0
Fair value of plan assets at end of year	0.9	1.0
United States | Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	5.7	5.7
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	5.7
Fair value of plan assets at end of year	6.8	5.7
United States | Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	3.3	3.3
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	3.3
Fair value of plan assets at end of year	4.3	3.3
United States | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	15.5	15.5
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	15.5
Fair value of plan assets at end of year	19.1	15.5
United States | Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	87.6	87.6
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	87.6
Fair value of plan assets at end of year	94.7	87.6
United States | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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 | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	65.7	65.7
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	65.7
Fair value of plan assets at end of year	74.6	65.7
United States | Fair Value Measured at Net Asset Value Per Share | Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	5.7	5.7
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	5.7
Fair value of plan assets at end of year	6.8	5.7
United States | Fair Value Measured at Net Asset Value Per Share | Domestic small cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	3.3	3.3
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	3.3
Fair value of plan assets at end of year	4.3	3.3
United States | Fair Value Measured at Net Asset Value Per Share | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	15.5	15.5
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	15.5
Fair value of plan assets at end of year	19.1	15.5
United States | Fair Value Measured at Net Asset Value Per Share | Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	41.2	41.2
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	41.2
Fair value of plan assets at end of year	44.4	41.2
United States | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.0	1.0
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.0
Fair value of plan assets at end of year	0.9	1.0
United States | Level 1 | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.0	1.0
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.0
Fair value of plan assets at end of year	0.9	1.0
United States | Level 1 | 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
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 | 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
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 | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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 | 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
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 | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	46.4	46.4
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	46.4
Fair value of plan assets at end of year	50.3	46.4
United States | Level 2 | 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
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 | 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
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 | 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
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 | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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 | Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	46.4	46.4
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	46.4
Fair value of plan assets at end of year	50.3	46.4
United States | Level 2 | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.0	0.1
Realized and unrealized gains	0.0	0.0
Purchases	0.0	0.0
Sales	0.0	(0.1)
Fair value of plan assets at end of year	0.0	0.0
United States | Level 3 | 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
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 | 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
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 | 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
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 | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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 | 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
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 | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.1	3.2
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	2.1	3.2
Fair value of plan assets at end of year	1.1	2.1
France | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.9	0.9
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.9
Fair value of plan assets at end of year	0.4	0.9
France | Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.6	0.6
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.6
Fair value of plan assets at end of year	0.3	0.6
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
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
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	0.5	0.5
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.5
Fair value of plan assets at end of year	0.3	0.5
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
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
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	1.5	1.5
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	1.5
Fair value of plan assets at end of year	0.7	1.5
France | Level 1 | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.9	0.9
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.9
Fair value of plan assets at end of year	0.4	0.9
France | Level 1 | Domestic large cap
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.6	0.6
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.6
Fair value of plan assets at end of year	0.3	0.6
France | Level 1 | 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
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 | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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 | 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
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 | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.6	0.6
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.6
Fair value of plan assets at end of year	0.4	0.6
France | Level 2 | 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
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 | 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
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 | 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
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 | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.0	0.0
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 | Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.5	0.5
Level 3 Asset Reconciliation
Fair value of plan assets at beginning of year	0.5
Fair value of plan assets at end of year	0.3	0.5
France | Level 2 | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value of plan assets	0.1	0.1
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