INCOME TAXES - COMPONENTS OF TAX EXPENSE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current tax expense (benefit):
Federal	$ 392	$ 397	$ 229
State	48	30	27
Total current	440	427	256
Deferred tax expense:
Federal	77	60	103
State	14	(23)	11
Total deferred	91	37	114
Total tax expense related to income	$ 531	$ 464	$ 370