Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Schedule Of Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis

The following fair value hierarchy table categorizes information regarding our net financial assets measured at fair value on a recurring basis as of December 31, 2015 and 2014 (in millions):



	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)		Total
As of December 31, 2015
Supplemental executive retirement plan assets	$	33.1	$	—		$	—	$	33.1
Total financial assets	33.1		—			—		33.1
Derivatives, net	—		(19.7		)	—		(19.7		)
Total financial liabilities	$	—	$	(19.7	)	$	—	$	(19.7	)
As of December 31, 2014
Supplemental executive retirement plan assets	$	43.2	$	—		$	—	$	43.2
Total financial assets	43.2		—			—		43.2
Derivatives, net	—		(26.3		)	—		(26.3		)
Total financial liabilities	$	—	$	(26.3	)	$	—	$	(26.3	)

Schedule Of Carrying Values And Estimated Fair Values Of Debt Instruments

The carrying values and estimated fair values of our debt instruments as of December 31, 2015 and 2014 were as follows (in millions):



	December 31, 2015				December 31, 2014
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value

4.70% Senior notes due 2021	$	1,482.7	$	1,254.0	$	1,479.9	$	1,505.3
5.75% Senior notes due 2044	1,004.2		707.1		622.3		615.8
6.875% Senior notes due 2020	990.9		850.5		1,008.2		1,008.5
5.20% Senior notes due 2025	697.6		505.2		—		—
4.50% Senior notes due 2024	624.3		417.4		624.2		602.0
8.50% Senior notes due 2019	566.4		510.2		583.8		611.8
7.875% Senior notes due 2040	379.8		244.0		381.2		363.8
7.20% Debentures due 2027	149.2		133.5		149.2		171.4
3.25% Senior notes due 2016	—		—		998.0		1,018.3
4.33% MARAD bonds due 2016	—		—		46.6		46.8
4.65% MARAD bonds due 2020	—		—		27.0		29.7
Total	$	5,895.1	$	4,621.9	$	5,920.4	$	5,973.4