CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
OPERATING ACTIVITIES
Net income				$ 813	$ 638
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses				163	166
Originations of mortgage loans held for sale				(1,345)	(1,394)
Proceeds from sales of mortgage loans held for sale				1,325	1,544
Purchases of commercial loans held for sale				(1,024)	(1,001)
Proceeds from sales of commercial loans held for sale				1,039	946
Depreciation, amortization and accretion				243	258
Mortgage servicing rights valuation recovery				(3)	(1)
Debt securities impairment		$ 1	$ 4	2	5
Deferred income taxes				10	(20)
Share-based compensation				28	27
Net gain on sales of:
Debt securities				(10)	(7)
Equity securities				0	(1)
Decrease in other assets				283	32
Decrease in other liabilities				(109)	(655)
Net cash provided by operating activities				1,415	537
Investment securities:
Purchases of debt securities available for sale				(2,343)	(2,282)
Proceeds from maturities and paydowns of debt securities available for sale				1,636	1,670
Proceeds from sales of debt securities available for sale				273	407
Purchases of debt securities held to maturity				0	(171)
Proceeds from maturities and paydowns of debt securities held to maturity				271	277
Purchases of equity securities, at fair value				(80)	(174)
Proceeds from sales of equity securities, at fair value				78	172
Purchases of equity securities, at cost				(334)	(243)
Proceeds from sales of equity securities, at cost				287	409
Net decrease in interest-bearing deposits in banks				78	6
Purchases of mortgage servicing rights				(16)	0
Net increase in loans and leases				(2,992)	(1,785)
Net increase in bank-owned life insurance				(21)	(24)
Premises and equipment:
Purchases				(94)	(64)
Capitalization of software				(116)	(83)
Net cash used in investing activities				(3,373)	(1,885)
FINANCING ACTIVITIES
Net increase in deposits				1,984	3,809
Net decrease in federal funds purchased and securities sold under agreements to repurchase				(489)	(719)
Net decrease in other short-term borrowed funds				(2,356)	(1,208)
Proceeds from issuance of long-term borrowed funds				11,500	10,109
Repayments of long-term borrowed funds				(7,584)	(9,751)
Treasury stock purchased				(325)	(260)
Net proceeds from issuance of preferred stock				296	0
Dividends declared and paid to common stockholders				(215)	(143)
Dividends declared and paid to preferred stockholders				(7)	(7)
Payments of employee tax withholding for share-based compensation				(13)	(19)
Net cash provided by financing activities				2,791	1,811
Increase in cash and cash equivalents	[1]			833	463
Cash and cash equivalents at beginning of period	[1]			3,032	3,704	$ 3,704
Cash and cash equivalents at end of period	[1]	$ 3,865	$ 4,167	$ 3,865	$ 4,167	$ 3,032

[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.