Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary Of Non-Vested Share Award Related Compensation Expense Recognized

The following table summarizes non-vested share award related compensation expense recognized during each of the years in the three-year period ended December 31, 2015 (in millions):



	2015			2014			2013
Contract drilling	$	19.5		$	20.9		$	21.3
General and administrative	17.8			20.7			21.6
Non-vested share award related compensation expense included in operating expenses	37.3			41.6			42.9
Tax benefit	(4.8		)	(5.1		)	(5.4		)
Total non-vested share award related compensation expense included in net income	$	32.5		$	36.5		$	37.5

Summary Of Value Of Non-Vested Share Awards Granted And Vested

The following table summarizes the value of non-vested shares granted and vested during each of the years in the three-year period ended December 31, 2015:



	2015		2014		2013
Weighted-average grant-date fair value of non-vested share awards granted (per share)	$	23.95	$	51.22	$	59.79
Total fair value of non-vested share awards vested during the period (in millions)	$	18.0	$	46.2	$	49.6

Summary Of Non-Vested Share Award Activity

The following table summarizes non-vested share activity for the year ended December 31, 2015 (shares in thousands):



	Shares		Weighted-Average Grant-Date Fair Value
Non-vested share awards as of December 31, 2014	2,641		$	52.86
Granted	2,116		23.95
Vested	(787	)	51.42
Forfeited	(827	)	41.23
Non-vested share awards as of December 31, 2015	3,143		$	36.46