LOANS AND LEASES - Loans Held For Sale (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	$ 1,993	$ 1,219
Other loans held for sale	22	101
Residential loans held for sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	1,824	967
Other loans held for sale	0	0
Commercial loans held for sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	169	252
Other loans held for sale	$ 22	$ 101