INCENTIVE PLANS - Future Expenses (Details) $ in Millions	Dec. 31, 2017 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock awards	$ 500
Deferred cash awards	310
Future expense related to awards already granted	810
Future expense related to awards granted in 2018	682
Total	1,492
2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock awards	276
Deferred cash awards	170
Future expense related to awards already granted	446
Future expense related to awards granted in 2018	238
Total	684
2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock awards	146
Deferred cash awards	94
Future expense related to awards already granted	240
Future expense related to awards granted in 2018	185
Total	425
2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock awards	67
Deferred cash awards	38
Future expense related to awards already granted	105
Future expense related to awards granted in 2018	148
Total	253
2021 and beyond
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock awards	11
Deferred cash awards	8
Future expense related to awards already granted	19
Future expense related to awards granted in 2018	111
Total	$ 130