Employee Stock-Based Compensation and Benefit Plans (Schedule of Non-vested Stock Unit Activity) (Details) - Non-vested stock - $ / shares	1 Months Ended			12 Months Ended
	Mar. 31, 2016	Jan. 31, 2016	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
Number of Shares
Non-vested stock units at December 31, 2015 (in shares)		5,147,926		5,147,926
Granted (in shares)				2,538,589
Vested (in shares)				(2,472,217)
Forfeited (in shares)				(822,462)
Non-vested stock units at December 31, 2016 (in shares)				4,391,836
Weighted- Average Fair Value at Grant Date
Non-vested stock units at December 31, 2015 (in dollars per share)		$ 65.00		$ 65.00
Granted (in dollars per share)	$ 66.18	$ 49.68	$ 61.01	76.27	$ 56.94
Vested (in dollars per share)				66.25
Forfeited (in dollars per share)				65.59
Non-vested stock units at December 31, 2016 (in dollars per share)				$ 70.67