INCOME TAXES - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Other comprehensive income	$ 141	$ 366
Allowance for credit losses	315	308
State net operating loss carryforwards	62	90
Accrued expenses not currently deductible	24	36
Investment and other tax credit carryforwards	89	74
Fair value adjustments	0	28
Total deferred tax assets	631	902
Valuation allowance	(79)	(110)
Deferred tax assets, net of valuation allowance	552	792
Deferred tax liabilities:
Leasing transactions	513	527
Amortization of intangibles	370	364
Depreciation	186	195
Pension and other employee compensation plans	124	127
Partnerships	71	51
Deferred Income	79	50
MSRs	75	51
Total deferred tax liabilities	1,418	1,365
Net deferred tax liability	$ 866	$ 573