Fair Value Measurements - Commodity and Foreign Currency Contracts (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Offsetting Assets [Line Items]
Gross Amounts Recognized	$ 694.8	$ 261.1
Gross Amounts Offset	509.7	131.1
Net Amounts Presented	185.1	130.0
Cash Collateral	7.5	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	177.7	130.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	639.1	266.6
Gross Amounts Offset	509.7	131.1
Net Amounts Presented	129.4	135.5
Cash Collateral	19.5	29.3
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	109.9	106.3
Commodity contracts
Offsetting Assets [Line Items]
Gross Amounts Recognized	692.4	259.0
Gross Amounts Offset	507.5	130.0
Net Amounts Presented	184.9	129.0
Cash Collateral	7.5	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	177.4	129.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	623.2	255.0
Gross Amounts Offset	507.5	130.0
Net Amounts Presented	115.7	125.0
Cash Collateral	19.5	29.3
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	96.2	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	4.9
Gross Amounts Offset	0.0
Net Amounts Presented	4.9
Cash Collateral	0.0
Gross Amounts without Right of Offset	0.0
Net Amounts	4.9
Foreign currency contracts
Offsetting Assets [Line Items]
Gross Amounts Recognized	2.4	2.0
Gross Amounts Offset	2.2	1.0
Net Amounts Presented	0.3	1.0
Cash Collateral	0.0	0.0
Gross Amounts without Right of Offset	0.0	0.0
Net Amounts	0.3	1.0
Offsetting Liabilities [Line Items]
Gross Amounts Recognized	10.9	11.6
Gross Amounts Offset	2.2	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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