CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING ACTIVITIES
Net income		$ 1,652	$ 1,045	$ 840
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses		321	369	302
Originations of mortgage loans held for sale		(2,911)	(2,829)	(2,363)
Proceeds from sales of mortgage loans held for sale		3,161	2,652	2,381
Purchases of commercial loans held for sale		(2,057)	(1,355)	(1,176)
Proceeds from sales of commercial loans held for sale		1,963	1,335	1,158
Amortization of terminated cash flow hedges, net		(15)	(8)	17
Depreciation, amortization and accretion		502	523	471
Mortgage servicing rights valuation recovery		(2)	(4)	(9)
Securities impairment		7	12	7
Deferred income taxes		(136)	153	249
Share-based compensation		48	23	24
Net gain on sales of:
Debt securities		(11)	(16)	(29)
Marketable equity securities available for sale		(1)	(3)	(3)
Premises and equipment		0	(2)	(9)
Extinguishment of debt		0	0	(3)
Other loans held for sale		(17)	(72)	0
Increase in other assets		(502)	(274)	(467)
Decrease in other liabilities		(119)	(59)	(161)
Net cash provided by operating activities		1,883	1,490	1,229
INVESTING ACTIVITIES
Purchases of securities available for sale		(5,394)	(7,664)	(6,783)
Proceeds from maturities and paydowns of securities available for sale		3,470	3,785	3,420
Proceeds from sales of securities available for sale		1,257	1,966	3,916
Purchases of securities held to maturity		(171)	(523)	(932)
Proceeds from maturities and paydowns of securities held to maturity		561	720	761
Proceeds from sales of securities held to maturity		0	0	72
Purchases of other investment securities, at fair value		(326)	(246)	(157)
Proceeds from sales of other investment securities, at fair value		253	220	120
Purchases of other investment securities, at cost		(400)	(166)	(91)
Proceeds from sales of other investment securities, at cost		637	87	95
Net decrease (increase) in interest-bearing deposits in banks		247	(83)	14
Purchases of mortgage servicing rights		(28)	0	0
Net increase in loans and leases		(3,634)	(9,074)	(6,019)
Net increase in bank-owned life insurance		(44)	(48)	(37)
Premises and equipment:
Purchases		(253)	(138)	(121)
Proceeds from sales		0	3	15
Capitalization of software		(159)	(165)	(178)
Net cash used in investing activities		(3,984)	(11,326)	(5,905)
FINANCING ACTIVITIES
Net increase in deposits		5,285	7,265	6,832
Net (decrease) increase in federal funds purchased and securities sold under agreements to repurchase		(333)	346	(3,474)
Net decrease in other short-term borrowed funds		(4,959)	(3,186)	(4,383)
Proceeds from issuance of long-term borrowed funds		15,363	15,144	6,750
Repayments of long-term borrowed funds		(12,751)	(8,429)	(766)
Treasury stock purchased		(820)	(430)	(500)
Net proceeds from issuance of preferred stock		0	0	247
Dividends declared and paid to common stockholders		(322)	(241)	(214)
Dividends declared and paid to preferred stockholders		(14)	(14)	(7)
Payments Related to Tax Withholding for Share-based Compensation		(20)	0	0
Net cash provided by financing activities		1,429	10,455	4,485
(Decrease) increase in cash and cash equivalents	[1]	(672)	619	(191)
Cash and cash equivalents at beginning of period	[1]	3,704	3,085	3,276
Cash and cash equivalents at end of period	[1]	3,032	3,704	3,085
Supplemental disclosures:
Interest paid		716	505	454
Income taxes paid		371	94	157
Non-cash items:
Loans securitized and transferred to securities available for sale		134	68	3
Stock purchased for share-based compensation plans		22	12	40
Stock purchased for Employee Stock Purchase Plan		12	10	9
Due from broker for securities sold but not settled		6	0	0
Income tax withholding on stock purchased for share based compensation		$ 0	$ 0	$ 22

[1] Cash and cash equivalents includes cash and due from banks and interest-bearing cash and due from banks as reflected on the Consolidated Balance Sheets.