Quarterly report pursuant to Section 13 or 15(d)

Per Share Information - Narrative (Details)

v3.10.0.1
Per Share Information - Narrative (Details) - shares
shares in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Earnings Per Share [Abstract]        
Weighted average unvested stock-based awards (participating securities) 2.6 2.3 2.6 2.5