Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Narrative (Details)

v3.8.0.1
Share-Based Compensation - Narrative (Details) - 2011 Incentive Plan [Member]
shares in Millions
 3 Months Ended
Mar. 31, 2018
shares
Restricted Stock Units (RSUs) [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of units granted 1.5
Award Vesting Period, Vests Ratably Over Service Period 3 years
Performance Units [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of units granted 0.2
Award Vesting Period, Cliff Vesting 3 years
Performance Units [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Percentage of Target Amount Earned Upon Vesting If Threshold Performance is Met 50.00%
Performance Units [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Percentage of Target Amount Earned Upon Vesting If Threshold Performance is Met 200.00%