PARENT COMPANY ONLY FINANCIALS - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ASSETS:
Cash and due from banks	$ 955	$ 1,099
Other assets	2,993	2,841
TOTAL ASSETS	149,520	138,208
LIABILITIES:
Long-term borrowed funds	12,790	9,886
Other liabilities	1,447	1,490
TOTAL LIABILITIES	129,773	118,562
TOTAL STOCKHOLDERS’ EQUITY	19,747	19,646	$ 19,268	$ 19,196
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	149,520	138,208
Parent company
ASSETS:
Cash and due from banks	671	531
Other assets	128	160
TOTAL ASSETS	22,141	22,335
LIABILITIES:
Other liabilities	76	93
TOTAL LIABILITIES	2,394	2,689
TOTAL STOCKHOLDERS’ EQUITY	19,747	19,646
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	22,141	22,335
Bank subsidiaries | Parent company
ASSETS:
Loans and advances	1,156	1,725
Investments in subsidiaries	20,116	19,865
Related bank holding companies | Parent company
ASSETS:
Loans and advances	20	0
Unaffiliated companies | Parent company
LIABILITIES:
Long-term borrowed funds	2,318	2,595
Nonbank subsidiaries | Parent company
ASSETS:
Investments in subsidiaries	50	54
LIABILITIES:
Balances due to nonbank subsidiaries	$ 0	$ 1