Repurchases of Common Stock (Accelerated Stock Repurchase Program) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014
Accelerated Share Repurchases [Line Items]
Repurchases of common stock	$ 50,000	$ 474,569
Open Market Share Repurchase [Member]
Accelerated Share Repurchases [Line Items]
Total shares delivered from DSB Agreement		1,447,556
Treasury Stock Acquired, Average Cost Per Share		$ 69.08
Repurchases of common stock		99,995
Tender Offer [Member]
Accelerated Share Repurchases [Line Items]
Total shares delivered from DSB Agreement		5,291,701
Treasury Stock Acquired, Average Cost Per Share		$ 70.07
Repurchases of common stock		$ 370,789	[1]

[1] Excludes expenses of $3.8 million associated with the tender offer.