Fair Value Measurements - Assets and Liabilities (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Assets:
Gross Derivative Assets	$ 1,428,000,000.0	$ 261,100,000
Liabilities:
Gross Derivative Liabilities	1,294,600,000	266,600,000
Transfers from Level 1 to Level 2, assets	0	0
Transfers from Level 2 to Level 1, assets	0	0
Transfers from Level 1 to Level 2, liabilities	0	0
Transfers from Level 2 to Level 1, liabilities	0	0
Fair value measured on recurring basis
Assets:
Total assets at fair value	1,437,000,000.0	270,400,000
Liabilities:
Total liabilities at fair value	1,294,600,000	266,600,000
Fair value measured on recurring basis | Level 1 Inputs
Assets:
Total assets at fair value	930,100,000	148,300,000
Liabilities:
Total liabilities at fair value	965,400,000	177,600,000
Fair value measured on recurring basis | Level 2 Inputs
Assets and liabilities measured at estimated fair value on a recurring basis
Debt	1,200,000,000	600,000,000
Notes receivable	24,500,000	21,000,000.0
Assets:
Total assets at fair value	462,300,000	111,400,000
Liabilities:
Total liabilities at fair value	318,300,000	80,900,000
Fair value measured on recurring basis | Level 3 Inputs
Assets:
Total assets at fair value	44,600,000	10,700,000
Liabilities:
Total liabilities at fair value	11,000,000.0	8,100,000
Commodity contracts | Fair value measured on recurring basis
Assets:
Gross Derivative Assets	1,400,900,000	259,000,000.0
Liabilities:
Gross Derivative Liabilities	1,282,800,000	255,000,000.0
Commodity contracts | Fair value measured on recurring basis | Level 1 Inputs
Assets:
Gross Derivative Assets	930,100,000	148,300,000
Liabilities:
Gross Derivative Liabilities	965,400,000	177,600,000
Commodity contracts | Fair value measured on recurring basis | Level 2 Inputs
Assets:
Gross Derivative Assets	426,200,000	100,000,000.0
Liabilities:
Gross Derivative Liabilities	306,500,000	69,300,000
Commodity contracts | Fair value measured on recurring basis | Level 3 Inputs
Assets:
Gross Derivative Assets	44,600,000	10,700,000
Liabilities:
Gross Derivative Liabilities	11,000,000.0	8,100,000
Foreign currency contracts | Fair value measured on recurring basis
Assets:
Gross Derivative Assets	27,100,000	2,000,000.0
Liabilities:
Gross Derivative Liabilities	9,800,000	11,600,000
Foreign currency contracts | Fair value measured on recurring basis | Level 1 Inputs
Assets:
Gross Derivative Assets	0	0
Liabilities:
Gross Derivative Liabilities	0	0
Foreign currency contracts | Fair value measured on recurring basis | Level 2 Inputs
Assets:
Gross Derivative Assets	27,100,000	2,000,000.0
Liabilities:
Gross Derivative Liabilities	9,800,000	11,600,000
Foreign currency contracts | Fair value measured on recurring basis | Level 3 Inputs
Assets:
Gross Derivative Assets	0	0
Liabilities:
Gross Derivative Liabilities	0	0
Interest rate contracts | Fair value measured on recurring basis
Assets:
Gross Derivative Assets	0
Liabilities:
Gross Derivative Liabilities	2,000,000.0
Interest rate contracts | Fair value measured on recurring basis | Level 1 Inputs
Assets:
Gross Derivative Assets	0
Liabilities:
Gross Derivative Liabilities	0
Interest rate contracts | Fair value measured on recurring basis | Level 2 Inputs
Assets:
Gross Derivative Assets	0
Liabilities:
Gross Derivative Liabilities	2,000,000.0
Interest rate contracts | Fair value measured on recurring basis | Level 3 Inputs
Assets:
Gross Derivative Assets	0
Liabilities:
Gross Derivative Liabilities	0
Cash surrender value of life insurance | Fair value measured on recurring basis
Assets:
Cash surrender value of life insurance	9,000,000.0	9,400,000
Cash surrender value of life insurance | Fair value measured on recurring basis | Level 1 Inputs
Assets:
Cash surrender value of life insurance	0	0
Cash surrender value of life insurance | Fair value measured on recurring basis | Level 2 Inputs
Assets:
Cash surrender value of life insurance	9,000,000.0	9,400,000
Cash surrender value of life insurance | Fair value measured on recurring basis | Level 3 Inputs
Assets:
Cash surrender value of life insurance	$ 0	$ 0