CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES
Net income	$ 320	$ 223
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	96	91
Originations of mortgage loans held for sale	(655)	(484)
Proceeds from sales of mortgage loans held for sale	815	479
Purchases of commercial loans held for sale	(384)	(362)
Proceeds from sales of commercial loans held for sale	380	345
Amortization of terminated cash flow hedges	(1)	15
Depreciation, amortization and accretion	125	112
Mortgage servicing rights valuation charge-off	0	5
Securities impairment	1	1
Deferred income taxes	39	30
Share-based compensation	18	4
Net gain on sales of:
Debt securities	(4)	(9)
Premises and equipment	0	(2)
Decrease (increase) in other assets	282	(339)
(Decrease) increase in other liabilities	(179)	265
Net cash provided by operating activities	853	374
Investment securities:
Purchases of securities available for sale	(1,705)	(706)
Proceeds from maturities and paydowns of securities available for sale	809	709
Proceeds from sales of securities available for sale	404	217
Purchases of securities held to maturity	(57)	0
Proceeds from maturities and paydowns of securities held to maturity	136	131
Purchases of other investment securities, at fair value	(73)	(51)
Proceeds from sales of other investment securities, at fair value	68	53
Purchases of other investment securities, at cost	(98)	(37)
Proceeds from sales of other investment securities, at cost	118	4
Net decrease (increase) in interest-bearing deposits in banks	88	(178)
Net increase in loans and leases	(769)	(2,401)
Net increase in bank-owned life insurance	(11)	(12)
Premises and equipment:
Purchases	(14)	(8)
Proceeds from sales	0	3
Capitalization of software	(39)	(45)
Net cash used in investing activities	(1,143)	(2,321)
FINANCING ACTIVITIES
Net increase in deposits	2,308	67
Net decrease in federal funds purchased and securities sold under agreements to repurchase	(55)	(88)
Net (decrease) increase in other short-term borrowed funds	(450)	670
Proceeds from issuance of long-term borrowed funds	2,997	750
Repayments of long-term borrowed funds	(4,000)	(629)
Treasury stock purchased	(130)	0
Dividends declared and paid to common stockholders	(72)	(53)
Payments of employee tax withholding for share-based compensation	(19)	0
Net cash provided by financing activities	579	717
Increase (decrease) in cash and cash equivalents	289	(1,230)
Cash and cash equivalents at beginning of period	3,704	3,085
Cash and cash equivalents at end of period	$ 3,993	$ 1,855