Quarterly report pursuant to Section 13 or 15(d)

Per Share Information (Detail)

v3.10.0.1
Per Share Information (Detail) - shares
shares in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Earnings Per Share [Abstract]        
Weighted average shares outstanding attributable to participating securities (in shares) 2.6 2.3 2.5 2.5