CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
OPERATING ACTIVITIES
Net income			$ 763	$ 619
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses			267	211
Originations of mortgage loans held for sale			(1,904)	(1,836)
Proceeds from sales of mortgage loans held for sale			1,775	1,780
Purchases of commercial loans held for sale			(1,053)	(887)
Proceeds from sales of commercial loans held for sale			1,040	826
Amortization of terminated cash flow hedges			6	13
Depreciation, amortization and accretion			387	350
Mortgage servicing rights valuation charge-off (recovery)	$ 2	$ 1	6	(6)
Securities impairment	3	2	11	5
Deferred income taxes			143	76
Share-based compensation			15	22
Net gain on sales of:
Debt securities			(13)	(19)
Marketable equity securities available for sale			0	(3)
Premises and equipment			(2)	(9)
Increase in other assets			(305)	(306)
Increase (decrease) in other liabilities			62	(5)
Net cash provided by operating activities			1,198	831
INVESTING ACTIVITIES
Purchases of securities available for sale			(4,774)	(5,418)
Proceeds from maturities and paydowns of securities available for sale			2,658	2,660
Proceeds from sales of securities available for sale			785	3,180
Purchases of securities held to maturity			(523)	(811)
Proceeds from maturities and paydowns of securities held to maturity			503	610
Proceeds from sales of securities held to maturity			0	73
Purchases of other investment securities, at fair value			(204)	(109)
Proceeds from sales of other investment securities, at fair value			161	92
Purchases of other investment securities, at cost			(84)	(33)
Proceeds from sales of other investment securities, at cost			70	78
Net (increase) decrease in interest-bearing deposits in banks			(364)	7
Net increase in loans and leases			(6,724)	(4,315)
Net increase in bank-owned life insurance			(36)	(26)
Premises and equipment:
Purchases			(44)	(54)
Proceeds from sales			3	12
Capitalization of software			(126)	(142)
Net cash used in investing activities			(8,699)	(4,196)
FINANCING ACTIVITIES
Net increase in deposits			5,788	6,159
Net increase (decrease) in federal funds purchased and securities sold under agreements to repurchase			98	(2,983)
Net decrease in other short-term borrowed funds			(1,635)	(1,152)
Proceeds from issuance of long-term borrowed funds			9,644	250
Repayments of long-term borrowed funds			(6,128)	(8)
Treasury stock purchased	(250)		(250)	(500)
Net proceeds from issuance of preferred stock			0	247
Dividends declared and paid to common stockholders			(179)	(161)
Dividends declared and paid to preferred stockholders			(7)	(7)
Net cash provided by financing activities			7,331	1,845
Decrease in cash and cash equivalents			(170)	(1,520)
Cash and cash equivalents at beginning of period			3,085	3,276	$ 3,276
Cash and cash equivalents at end of period	$ 2,915	$ 1,756	$ 2,915	$ 1,756	$ 3,085