Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2016

Share Based Compensation Plans

Summary of activity for vested and unvested stock options outstanding

				Weighted-average
	Number	Weighted-average		remaining	Aggregate
	of shares	exercise price		contractual term	intrinsic value
	under option	per share		(years)	(in millions)
Outstanding at January 1, 2016	1,622,317	$	73.66	4.81	$	—
Granted	945,724		8.61
Forfeited	(633,346)		64.44
Outstanding at December 31, 2016	1,934,695	$	44.88	6.12	$	6
Vested and exercisable at December 31, 2016	1,022,393	$	77.24	3.45	$	—

Service-based awards

Share Based Compensation Plans

Summary of unvested deferred units activity

	Number	Weighted-average
	of	grant-date fair value
	units	per unit
Unvested at January 1, 2016	3,030,444	$	25.65
Granted	3,155,382		8.69
Vested	(1,725,734)		28.08
Forfeited	(454,010)		9.52
Unvested at December 31, 2016	4,006,082	$	13.10

Performance-based awards

Share Based Compensation Plans

Summary of unvested deferred units activity

	Number	Weighted-average
	of	grant-date fair value
	units	per unit
Unvested at January 1, 2016	702,131	$	18.81
Granted	997,362		11.60
Vested	(187,000)		32.05
Forfeited	(72,887)		17.12
Unvested at December 31, 2016	1,439,606	$	14.40