Common Stock Common Stock (Stock Repurchase Programs) (Details) - $ / shares	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Schedule of Common Stock Repurchases [Line Items]
Treasury Stock Acquired, Average Cost Per Share	$ 32.66	$ 31.57

Total cost of shares repurchased divided by the total number of shares repurchased.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Name:	us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration