Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

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

Summary Of Non-Vested Share Award Related Compensation Expense Recognized

The following table summarizes the share awards compensation expense recognized during each of the years in the three-year period ended December 31, 2016 (in millions):



	2016			2015			2014
Contract drilling	$	19.9		$	19.5		$	20.9
General and administrative	16.6			17.8			20.7
Share award compensation expense included in operating expenses	36.5			37.3			41.6
Tax benefit	(5.9		)	(4.8		)	(5.1		)
Total share award compensation expense included in net income	$	30.6		$	32.5		$	36.5

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

The following table summarizes the value of share awards granted and vested during each of the years in the three-year period ended December 31, 2016:



	2016		2015		2014
Weighted-average grant-date fair value of share awards granted (per share)	$	9.84	$	23.95	$	51.22
Total fair value of share awards vested during the period (in millions)	$	8.8	$	18.0	$	46.2

Summary Of Non-Vested Share Award Activity

The following table summarizes share awards activity for the year ended December 31, 2016 (shares in thousands):



	Shares		Weighted-Average Grant-Date Fair Value
Share awards as of December 31, 2015	3,143		$	36.46
Granted	4,542		9.84
Vested	(935	)	40.28
Forfeited	(618	)	20.13
Share awards as of December 31, 2016	6,132		$	17.85