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Postretirement and Other Benefits - Fair Value of Plan Assets (Details) - Pension Benefits - USD ($) $ in Millions | Dec. 31, 2020 | 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 | $ 134.4 | $ 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 | 0.9 |
United States | Domestic large cap |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 2.7 | 6.8 |
United States | Domestic small cap |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 1.3 | 4.3 |
United States | International |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 8.2 | 19.1 |
United States | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 13.9 | 20.9 |
United States | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 99.6 | 55.8 |
United States | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 1.2 | 0.8 |
United States | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 6.5 | 17.2 |
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 | 133.4 | 74.6 |
United States | Fair Value Measured at Net Asset Value Per Share | 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 |
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 | 2.7 | 6.8 |
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 | 1.3 | 4.3 |
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 | 8.2 | 19.1 |
United States | Fair Value Measured at Net Asset Value Per Share | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Fair Value Measured at Net Asset Value Per Share | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 13.9 | 20.9 |
United States | Fair Value Measured at Net Asset Value Per Share | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 99.6 | 5.5 |
United States | Fair Value Measured at Net Asset Value Per Share | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 1.2 | 0.8 |
United States | Fair Value Measured at Net Asset Value Per Share | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 6.5 | 17.2 |
United States | Level 1 |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 1.0 | 0.9 |
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 | 0.9 |
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 |
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 |
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 |
United States | Level 1 | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 1 | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 1 | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 1 | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 1 | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 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 | 0.0 | 50.3 |
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 |
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 |
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 |
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 |
United States | Level 2 | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 2 | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 2 | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 50.3 |
United States | Level 2 | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 2 | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 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 |
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 |
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 |
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 |
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 |
United States | Level 3 | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 3 | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 3 | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 3 | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
United States | Level 3 | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.8 | 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 | 0.3 | 0.4 |
France | Domestic large cap |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.2 | 0.3 |
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 |
France | International |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.1 |
France | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.3 | 0.3 |
France | Level 1 |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.5 | 0.7 |
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 | 0.3 | 0.4 |
France | Level 1 | Domestic large cap |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.2 | 0.3 |
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 |
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 |
France | Level 1 | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 1 | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 1 | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 1 | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 1 | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 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 | 0.3 | 0.4 |
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 |
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 |
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 |
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 |
France | Level 2 | Alternative Investment |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.1 |
France | Level 2 | US Treasury and Government |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 2 | Corporate Debt Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 2 | Debt Security, Government, Non-US |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | 0.0 | 0.0 |
France | Level 2 | Other Debt Obligations |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Fair value of plan assets | $ 0.3 | $ 0.3 |

X
- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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