Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Schedule of Share-Based Compensation (Details)

v3.8.0.1
Share-Based Compensation - Schedule of Share-Based Compensation (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total share-based compensation $ 34 $ 32
Capitalized share-based compensation (6) (8)
Total share-based compensation expense 28 24
Tax benefit associated with share-based compensation expense 2 0
Equity Awards [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total share-based compensation 17 5
Liability Awards [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total share-based compensation $ 17 $ 27