CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES
Net income	$ 1,045,000,000	$ 840,000,000	$ 865,000,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	369,000,000	302,000,000	319,000,000
Originations of mortgage loans held for sale	(2,829,000,000)	(2,363,000,000)	(1,615,000,000)
Proceeds from sales of mortgage loans held for sale	2,652,000,000	2,381,000,000	1,578,000,000
Purchases of commercial loans held for sale	(1,355,000,000)	(1,176,000,000)	(312,000,000)
Proceeds from sales of commercial loans held for sale	1,335,000,000	1,158,000,000	269,000,000
Amortization of terminated cash flow hedges	(8,000,000)	17,000,000	46,000,000
Depreciation, amortization and accretion	523,000,000	471,000,000	386,000,000
Mortgage servicing rights valuation recovery	(4,000,000)	(9,000,000)	(5,000,000)
Securities impairment	12,000,000	7,000,000	10,000,000
Deferred income taxes	153,000,000	249,000,000	141,000,000
Share-based compensation	23,000,000	24,000,000	53,000,000
Loss on disposal/impairment of premises and equipment	0	0	27,000,000
Loss on sale of other branch assets held for sale	0	0	9,000,000
Gain on sales of:
Debt securities	(16,000,000)	(29,000,000)	(28,000,000)
Marketable equity securities available for sale	(3,000,000)	(3,000,000)	0
Premises and equipment	(2,000,000)	(9,000,000)	0
Extinguishment of debt	0	(3,000,000)	0
Other loans held for sale	(72,000,000)	0	(11,000,000)
Deposits held for sale	0	0	(286,000,000)
Increase in other assets	(274,000,000)	(467,000,000)	(295,000,000)
(Decrease) increase in other liabilities	(59,000,000)	(161,000,000)	239,000,000
Net cash provided by operating activities	1,490,000,000	1,229,000,000	1,390,000,000
INVESTING ACTIVITIES
Purchases of securities available for sale	(7,664,000,000)	(6,783,000,000)	(8,315,000,000)
Proceeds from maturities and paydowns of securities available for sale	3,785,000,000	3,420,000,000	2,999,000,000
Proceeds from sales of securities available for sale	1,966,000,000	3,916,000,000	3,325,000,000
Purchases of securities held to maturity	(523,000,000)	(932,000,000)	(1,174,000,000)
Proceeds from maturities and paydowns of securities held to maturity	720,000,000	761,000,000	362,000,000
Proceeds from sales of securities held to maturity	0	72,000,000	0
Purchases of other investment securities, at fair value	(246,000,000)	(157,000,000)	0
Proceeds from sales of other investment securities, at fair value	220,000,000	120,000,000	0
Purchases of other investment securities, at cost	(166,000,000)	(91,000,000)	(84,000,000)
Proceeds from sales of other investment securities, at cost	87,000,000	95,000,000	146,000,000
Net (increase) decrease in interest-bearing deposits in banks	(83,000,000)	14,000,000	(137,000,000)
Net increase in loans and leases	(9,074,000,000)	(6,019,000,000)	(6,900,000,000)
Net increase in bank-owned life insurance	(48,000,000)	(37,000,000)	(188,000,000)
Premises and equipment:
Purchases	(138,000,000)	(121,000,000)	(141,000,000)
Proceeds from sales	3,000,000	15,000,000	3,000,000
Capitalization of software	(165,000,000)	(178,000,000)	(170,000,000)
Net cash used in investing activities	(11,326,000,000)	(5,905,000,000)	(10,274,000,000)
FINANCING ACTIVITIES
Net increase in deposits	7,265,000,000	6,832,000,000	3,813,000,000
Net increase (decrease) in federal funds purchased and securities sold under agreements to repurchase	346,000,000	(3,474,000,000)	(515,000,000)
Net (decrease) increase in other short-term borrowed funds	(3,186,000,000)	(4,383,000,000)	4,002,000,000
Proceeds from issuance of long-term borrowed funds	15,144,000,000	6,750,000,000	3,249,000,000
Repayments of long-term borrowed funds	(8,429,000,000)	(766,000,000)	(6,000,000)
Treasury stock purchased	(430,000,000)	(500,000,000)	(334,000,000)
Net proceeds from issuance of preferred stock	0	247,000,000	0
Dividends declared and paid to common stockholders	(241,000,000)	(214,000,000)	(806,000,000)
Dividends declared and paid to preferred stockholders	(14,000,000)	(7,000,000)	0
Net cash provided by financing activities	10,455,000,000	4,485,000,000	9,403,000,000
Increase (decrease) in cash and cash equivalents	619,000,000	(191,000,000)	519,000,000
Cash and cash equivalents at beginning of period	3,085,000,000	3,276,000,000	2,757,000,000
Cash and cash equivalents at end of period	3,704,000,000	3,085,000,000	3,276,000,000
Supplemental disclosures:
Interest paid	505,000,000	454,000,000	338,000,000
Income taxes paid	94,000,000	157,000,000	391,000,000
Non-cash items:
Loans securitized and transferred to securities available for sale	68,000,000	3,000,000	18,000,000
Income tax withholding on stock purchased for share based compensation	0	22,000,000	2,000,000
Stock purchased for share-based compensation plans	12,000,000	40,000,000	71,000,000
Stock purchased for Employee Stock Purchase Plan	$ 10,000,000	$ 9,000,000	$ 2,000,000