Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net income (loss)	$ 900	$ 737
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Provision for credit losses	125	129
Depreciation and amortization expense, net	195	198
Accretion of acquired loans	22	133
Increase in cash surrender value of corporate-owned life insurance	(56)	(56)
Stock-based compensation expense	53	51
FDIC reimbursement (payments), net of FDIC expense	2	(2)
Deferred income taxes (benefit)	17	212
Proceeds from sales of loans held for sale	5,703	4,881
Originations of loans held for sale, net of repayments	(5,944)	(5,435)
Net losses (gains) on sales of loans held for sale	(89)	(74)
Net losses (gains) and writedown on OREO	2	2
Net losses (gains) on leased equipment	(37)	(9)
Net securities losses (gains)	0	(1)
Net losses (gains) on sales of fixed assets	4	14
Net decrease (increase) in trading account assets	3	(214)
Gain on sale of Key Insurance & Benefits, Inc.	(78)	0
Other operating activities, net	(414)	(1,155)
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	408	(589)
INVESTING ACTIVITIES
Cash received (used) in acquisitions, net of cash acquired	0	(74)
Proceeds from sale of Key Insurance & Benefits Services, Inc.	119	0
Net decrease (increase) in short-term investments, excluding acquisitions	1,801	253
Purchases of securities available for sale	(1,167)	(723)
Proceeds from sales of securities available for sale	0	915
Proceeds from prepayments and maturities of securities available for sale	1,640	2,036
Proceeds from prepayments and maturities of held-to-maturity securities	797	890
Purchases of held-to-maturity securities	(1,242)	(1,297)
Purchases of other investments	(6)	(69)
Proceeds from sales of other investments	22	70
Proceeds from prepayments and maturities of other investments	2	2
Net decrease (increase) in loans, excluding acquisitions, sales and transfers	(2,044)	(832)
Proceeds from sales of portfolio loans	99	77
Proceeds from corporate-owned life insurance	41	25
Purchases of premises, equipment, and software	(36)	(24)
Proceeds from sales of premises and equipment	1	0
Proceeds from sales of OREO	14	19
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	41	1,268
FINANCING ACTIVITIES
Net increase (decrease) in deposits, excluding acquisitions	(687)	(1,266)
Net increase (decrease) in short-term borrowings	1,295	394
Net proceeds from issuance of long-term debt	1,758	950
Payments on long-term debt	(2,123)	(17)
Open market Common Share repurchases	(279)	(196)
Employee equity compensation program Common Share repurchases	(46)	(59)
Redemption of Preferred Stock Series C	0	(350)
Net proceeds from reissuance of Common Shares	14	25
Cash dividends paid	(268)	(236)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	(336)	(755)
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	113	(76)
CASH AND DUE FROM BANKS AT BEGINNING OF PERIOD	671	677
CASH AND DUE FROM BANKS AT END OF PERIOD	784	601
Additional disclosures relative to cash flows:
Interest paid	389	281
Income taxes paid (refunded)	14	60
Noncash items:
Reduction of secured borrowing and related collateral	15	21
Loans transferred to portfolio from held for sale	21	19
Loans transferred to (from) held for sale from portfolio	(3)	29
Loans transferred to OREO	$ 9	$ 19