INCOME TAXES - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Other comprehensive income	$ 366	$ 271
Allowance for credit losses	308	310
State net operating loss carryforwards	90	88
Accrued expenses not currently deductible	36	40
Investment and other tax credit carryforwards	74	65
Fair value adjustments	28	27
Total deferred tax assets	902	801
Valuation allowance	(110)	(105)
Deferred tax assets, net of valuation allowance	792	696
Deferred tax liabilities:
Leasing transactions	527	525
Amortization of intangibles	364	352
Depreciation	195	182
Pension and other employee compensation plans	127	110
Partnerships	51	37
Deferred Income	50	27
MSRs	51	34
Total deferred tax liabilities	1,365	1,267
Net deferred tax liability	$ 573	$ 571