Stock Repurchase (Schedule of Shares Repurchased) (Details) - $ / shares	1 Months Ended			3 Months Ended
	Mar. 31, 2016	Feb. 29, 2016	Jan. 31, 2016	Mar. 31, 2016
Class of Stock Disclosures [Abstract]
Number of Shares Repurchased (in shares)	1,405,025	869,898	1,147,337	3,422,260
Average Price Paid Per Share (in dollars per share)	$ 76.12	$ 70.69	$ 78.44	$ 75.52
Total Number of Shares Repurchased as Part of Publicly Announced Programs (in shares)	1,405,025	869,898	1,147,337	3,422,260