Fair Value Measurements - Commodity and Foreign Currency Contracts (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Offsetting Assets [Line Items]
Gross Amounts Recognized	$ 445.5	$ 261.1
Gross Amounts Offset	325.9	131.1
Net Amounts Presented	119.5	130.0
Cash Collateral	1.8	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	117.8	130.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	400.7	266.6
Gross Amounts Offset	325.9	131.1
Net Amounts Presented	74.8	135.5
Cash Collateral	0.0	29.3
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	74.8	106.3
Commodity contracts
Offsetting Assets [Line Items]
Gross Amounts Recognized	443.8	259.0
Gross Amounts Offset	324.3	130.0
Net Amounts Presented	119.5	129.0
Cash Collateral	1.8	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	117.8	129.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	385.5	255.0
Gross Amounts Offset	324.3	130.0
Net Amounts Presented	61.3	125.0
Cash Collateral	0.0	29.3
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	61.3	95.7
Interest rate contracts
Offsetting Assets [Line Items]
Gross Amounts Recognized	0.0
Gross Amounts Offset	0.0
Net Amounts Presented	0.0
Cash Collateral	0.0
Gross Amounts without Right of Offset	0.0
Net Amounts	0.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	4.7
Gross Amounts Offset	0.0
Net Amounts Presented	4.7
Cash Collateral	0.0
Gross Amounts without Right of Offset	0.0
Net Amounts	4.7
Foreign currency contracts
Offsetting Assets [Line Items]
Gross Amounts Recognized	1.6	2.0
Gross Amounts Offset	1.6	1.0
Net Amounts Presented	0.0	1.0
Cash Collateral	0.0	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	0.0	1.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	10.4	11.6
Gross Amounts Offset	1.6	1.0
Net Amounts Presented	8.8	10.5
Cash Collateral	0.0	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	$ 8.8	$ 10.5

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