Common Stock Issued and Outstanding (Tables)

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

Activity in Number of Shares of Common Stock Issued and Outstanding

(Number of shares outstanding)	2015	2014	2013
At beginning of year	177,499,513	183,406,513	190,641,317
Stock options exercised*	15,575	119,994	303,685
Restricted stock awards*	478,549	339,985	300,910
Employee stock purchase and thrift plans	8,387	6,739	16,020
Treasury shares purchased	(5,967,313)	(6,373,718)	(7,855,419)
At end of year	172,034,711	177,499,513	183,406,513

*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.