Common Stock Issued and Outstanding (Activity in the Number of Common Stock Shares Issued and Outstanding) (Details) - shares		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders; Equity, Common Stock Issued and Outstanding [Abstract]
At beginning of year		172,034,711	177,499,513	183,406,513
Stock options exercised	[1]		15,575	119,994
Restricted stock awards	[1]	158,504	478,549	339,985
Employee stock purchase and thrift plans		8,962	8,387	6,739
Treasury shares purchased			(5,967,313)	(6,373,718)
At end of year		172,202,177	172,034,711	177,499,513

[1] Shares issued upon exercise of stock options and award of restricted stock are less than the amount reflected in Note J due to withholdings for statutory income taxes owed upon issuance of shares.