Annual report pursuant to Section 13 and 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
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total share-based compensation $ 114 $ 117 $ 195
Capitalized share-based compensation (23) (16) (23)
Total share-based compensation expense 91 101 172
Tax benefit associated with share-based compensation expense 5 0 0
Equity Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total share-based compensation 34 41 90
Liability Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total share-based compensation $ 80 $ 76 $ 105