Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES
Net income	$ 925	$ 631
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(17)	57
Provision (benefit) for deferred income taxes	37	(48)
Depreciation and amortization	90	91
Net periodic defined benefit credit	(14)	(14)
Share-based compensation expense	41	29
Net amortization of securities	3	5
Accretion of loan purchase discount	(1)	(3)
Net securities losses	19	0
Net gains on sales of foreclosed property	(1)	(2)
Net change in accrued income receivable	(36)	(21)
Net change in accrued expenses payable	19	28
Other, net	(98)	97
Net cash provided by operating activities	967	850
INVESTING ACTIVITIES
Maturities and redemptions of investment securities available-for-sale	1,366	1,198
Sales of investment securities available-for-sale	1,256	1,259
Purchases of investment securities available-for-sale	(2,618)	(2,655)
Maturities and redemptions of investment securities held-to-maturity	0	241
Net change in loans	120	(193)
Proceeds from sales of foreclosed property	7	18
Net increase in premises and equipment	(65)	(43)
Purchases of Federal Home Loan Bank stock	(41)	(42)
Redemptions of Federal Home Loan Bank Stock	0	21
Proceeds from settlement of BOLI policies	4	8
Other, net	(2)	2
Net cash used in investing activities	27	(186)
FINANCING ACTIVITIES
Net change in deposits	(1,978)	(1,208)
Net change in short-term borrowings	74	484
Maturities of medium- and long-term debt	0	(500)
Issuances and advances of medium- and long-term debt	1,850	0
Terminations of medium- and long-term debt	0	(16)
Repurchases of common stock	(837)	(412)
Cash dividends paid on common stock	(161)	(128)
Issuances of common stock under employee stock plans	50	106
Other, net	2	(4)
Net cash used in financing activities	(1,000)	(1,678)
Net decrease in cash and cash equivalents	(6)	(1,014)
Cash and cash equivalents at beginning of period	5,845	7,218
Cash and cash equivalents at end of period	5,839	6,204
Interest paid	172	89
Income tax paid	125	247
Noncash investing and financing activities:
Loans transferred to other real estate	2	6
Securities transferred from held-to-maturity to available-for-sale	1,266	0
Securities transferred from available-for-sale to equity securities	$ 81	$ 0