Shareholders' Equity (Additional Information) (Detail)	12 Months Ended
	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares	Dec. 31, 2013 $ / shares
Equity [Abstract]
Preferred stock without par value (in dollars per share)	$ 10,000,000
Common stock par value (in dollars per share)	$ 1.667
Shares of common stock authorized | shares	1,200,000,000
Per share cash dividends paid (in dollars per share)	$ 1.41	$ 1.31	$ 1.21
Stockholders' Equity Note, Stock Split, Conversion Ratio	2