Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Assets and liabilities measured at fair value on a recurring basis

Assets and liabilities measured at fair value on a recurring basis are summarized below:



	Fair Value Measurements as of June 30, 2012
	Total		Level 1		Level 2		Level 3
	(in millions)
Cash and cash equivalents	$	415.0	$	415.0	$	—	$	—
Basis swaps	0.3		—		—		0.3
Option contracts	0.1		—		—		0.1
Total assets	$	415.4	$	415.0	$	—	$	0.4

Option contracts	$	1.4	$	—	$	—	$	1.4
Total liabilities	$	1.4	$	—	$	—	$	1.4



	Fair Value Measurements as of December 31, 2011
	Total		Level 1		Level 2		Level 3
	(in millions)
Cash and cash equivalents	$	343.3	$	343.3	$	—	$	—
Option contracts	1.0		—		—		1.0
Total assets	$	344.3	$	343.3	$	—	$	1.0

Option contracts	$	0.7	$	—	$	—	$	0.7
Total liabilities	$	0.7	$	—	$	—	$	0.7

Assets and liabilities measured at fair value on a recuring basis using significant unobservable inputs (level 3)

The following table presents the Company’s activity for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3):



	Fuel Derivative Activity for Six Months Ended June 30, 2012
	(in millions)
Balance at December 31, 2011	$	0.3
Total gains (losses) realized or unrealized included in earnings, net	2.2
Settlements, net	(2.4		)
Balance at March 31, 2012	$	0.1
Total gains (losses) realized or unrealized included in earnings, net	(3.6		)
Settlements, net	2.5
Balance at June 30, 2012	$	(1.0	)