Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Fair value and related carrying amount of certain financial instruments

The following table discloses the fair value and related carrying amount of certain financial instruments not disclosed in other Notes to the Consolidated Financial Statements in this Annual Report on Form 10-K:

	Carrying Amount		Level 1 Fair Value		Carrying Amount		Level 1 Fair Value
	December 31, 2015				December 31, 2014
	(in millions)
Financial Assets
Cash and cash equivalents	$	376.1	$	376.1	$	1,160.1	$	1,160.1
Financial Liabilities
Checks outstanding in excess of cash balances	$	29.8	$	29.8	$	54.7	$	54.7
Long-term debt	2,218.8		1,784.6		2,218.1		2,171.6

The fair value of financial assets and liabilities at December 31, 2015 and 2014, is shown in the table below:

	Fair Value Measurements
	Gross Amounts of Assets and Liabilities						Netting Adjustments(1)			Net Amounts Presented on the Consolidated Balance Sheet
	Level 1		Level 2		Level 3
	(in millions)
	December 31, 2015
Financial Assets
Commodity derivative instruments - short-term	$	—	$	147.8	$	—	$	(1.0	)	$	146.8
Commodity derivative instruments - long-term	—		23.2		—		—			23.2
Total financial assets	$	—	$	171.0	$	—	$	(1.0	)	$	170.0
Financial Liabilities
Commodity derivative instruments - short-term	$	—	$	1.8	$	—	$	(1.0	)	$	0.8
Commodity derivative instruments - long-term	—		4.0		—		—			4.0
Total financial liabilities	$	—	$	5.8	$	—	$	(1.0	)	$	4.8
	December 31, 2014
Financial Assets
Commodity derivative instruments - short-term	$	—	$	339.3	$	—	$	(0.3	)	$	339.0
Commodity derivative instruments - long-term	—		9.9		—		—			9.9
Total financial assets	$	—	$	349.2	$	—	$	(0.3	)	$	348.9
Financial Liabilities
Commodity derivative instruments - short-term	$	—	$	0.3	$	—	$	(0.3	)	$	—
Total financial liabilities	$	—	$	0.3	$	—	$	(0.3	)	$	—