Earnings Per Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Antidilutive securities excluded from earnings per share computation, shares	2.9	2.9	11.1	3.0
Antidilutive securities excluded from diluted weighted average shares computation, shares	40.9	40.9	40.9	27.3