Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of assets and liabilities measured at estimated fair value on a recurring basis

The following table presents information about our gross assets and liabilities that are measured at fair value on a recurring basis (in millions):

	Fair Value measurements as of September 30, 2018
		Level 1 Inputs		Level 2 Inputs		Level 3 Inputs		Total Fair Value
Assets:
Commodities contracts		$	421.8	$	131.4	$	3.5	$	556.7
Foreign currency contracts		—		2.4		—		2.4
Cash surrender value of life insurance		—		6.4		—		6.4
Total assets at fair value		$	421.8	$	140.2	$	3.5	$	565.5
Liabilities:
Commodities contracts		$	414.7	$	161.7	$	2.5	$	579.0
Foreign currency contracts		—		2.6		—		2.6
Total liabilities at fair value		$	414.7	$	164.3	$	2.5	$	581.6
	Fair Value measurements as of December 31, 2017
		Level 1 Inputs		Level 2 Inputs		Level 3 Inputs		Total Fair Value
Assets:
Commodities contracts		$	196.3	$	106.1	$	1.2	$	303.6
Foreign currency contracts		—		8.5		—		8.5
Cash surrender value of life insurance		—		5.6		—		5.6
Total assets at fair value		$	196.3	$	120.2	$	1.2	$	317.7
Liabilities:
Commodities contracts		$	210.6	$	111.8	$	1.4	$	323.9
Foreign currency contracts		—		8.7		—		8.7
Total liabilities at fair value		$	210.6	$	120.5	$	1.4	$	332.5

Schedule of derivative instruments at fair value and their locations on the balance sheets

The following tables summarize those commodity derivative balances subject to the right of offset as presented on our consolidated balance sheet. We have elected to offset the recognized fair value amounts for multiple derivative instruments executed with the same counterparty in our financial statements when a legal right of offset exists.

	Fair Value as of September 30, 2018
										Gross Amounts
		Gross Amounts		Gross Amounts		Net Amounts		Cash		without
		Recognized		Offset		Presented		Collateral		Right of Offset		Net Amounts
Assets:
Commodities contracts		$	556.7	$	474.2	$	82.5	$	—	$	—	$	82.5
Foreign currency contracts		2.4		1.2		1.2		—		—		1.2
Total assets at fair value		$	559.1	$	475.4	$	83.7	$	—	$	—	$	83.7
Liabilities:
Commodities contracts		$	579.0	$	474.2	$	104.8	$	—	$	—	$	104.8
Foreign currency contracts		2.6		1.2		1.4		—		—		1.4
Total liabilities at fair value		$	581.6	$	475.4	$	106.2	$	—	$	—	$	106.2

	Fair Value as of December 31, 2017
										Gross Amounts
		Gross Amounts		Gross Amounts		Net Amounts		Cash		without
		Recognized		Offset		Presented		Collateral		Right of Offset		Net Amounts
Assets:
Commodities contracts		$	303.6	$	228.4	$	75.1	$	21.2	$	—	$	53.9
Foreign currency contracts		8.5		6.7		1.7		—		—		1.7
Total assets at fair value		$	312.0	$	235.2	$	76.9	$	21.2	$	—	$	55.7
Liabilities:
Commodities contracts		$	323.9	$	228.4	$	95.4	$	39.2	$	—	$	56.2
Foreign currency contracts		8.7		6.7		2.0		—		—		2.0
Total liabilities at fair value		$	332.5	$	235.2	$	97.4	$	39.2	$	—	$	58.2