Capital Stock - Additional Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 15, 2015	Dec. 31, 2014
Schedule Of Capital Stock [Line Items]
All classes of stock, shares authorized	1,020,000,000
Shares of all classes of stock, par value	$ 0.01
Common stock, shares authorized	1,000,000,000
Preferred stock, shares authorized	10,000,000		10,000,000
Shares repurchased during the period	10,900,000
Shares issued during the period for stock-based compensation plans	3,200,000
Dividends declaration date	Dec. 16, 2014
Dividends payable date	Mar. 10, 2015
Dividends payable record date	Feb. 20, 2015
Quarterly dividend declare		$ 0.37
Series Common Stock [Member]
Schedule Of Capital Stock [Line Items]
Common stock, shares authorized	10,000,000		10,000,000