Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 1,929,149	$ 1,918,080	$ 1,408,306
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	176,000	132,000	168,000
Depreciation and amortization of premises and equipment	209,937	104,864	109,587
Amortization of capitalized servicing rights	71,888	49,619	56,172
Amortization of core deposit and other intangible assets	19,490	24,522	31,366
Provision for deferred income taxes	57,548	15,857	400,790
Asset write-downs	7,701	24,774	15,429
Net (gain) loss on sales of assets	31,526	(23,503)	(53,467)
Net change in accrued interest receivable, payable	30,923	(7,162)	(17,896)
Net change in other accrued income and expense	75,930	13,436	(201,981)
Net change in loans originated for sale	130,230	(150,695)	711,657
Net change in trading account assets and liabilities	(382,767)	(11,940)	153,972
Net cash provided by operating activities	2,357,555	2,089,852	2,781,935
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale	107	418	534,160
Proceeds from sales of investment securities equity and other	1,169,876	650,858	178,468
Proceeds from maturities of investment securities Available for sale	2,621,603	1,997,263	2,131,118
Proceeds from maturities of investment securities Held to maturity	1,162,820	478,172	528,585
Purchases of investment securities Available for sale	(28,120)	(12,494)	(251,185)
Purchases of investment securities Held to maturity	(495,277)	(444,703)	(1,425,690)
Purchases of investment securities equity and other	(979,734)	(834,856)	(132,378)
Net (increase) decrease in loans and leases	(2,795,263)	(475,895)	1,931,492
Net (increase) decrease in interest-bearing deposits at banks	915,043	(3,026,294)	(78,265)
Capital expenditures, net	(178,049)	(97,676)	(78,966)
Net (increase) decrease in loan servicing advances	(470,078)	307,252	37,761
Other, net	(195,921)	47,904	19,825
Net cash provided (used) by investing activities	727,007	(1,410,051)	3,394,925
Cash flows from financing activities
Net increase (decrease) in deposits	4,616,082	(2,272,505)	(3,075,322)
Net increase (decrease) in short-term borrowings	(4,336,015)	4,223,279	11,657
Proceeds from long-term borrowings		1,773,189	2,145,950
Payments on long-term borrowings	(1,553,493)	(1,459,081)	(3,433,440)
Purchases of treasury stock	(1,349,785)	(2,194,396)	(1,205,905)
Dividends paid — common	(552,138)	(510,382)	(457,402)
Dividends paid — preferred	(67,454)	(72,521)	(72,734)
Redemption of Series A and Series C preferred stock	(381,500)
Other, net	(25,393)	17,167	10,675
Net cash used by financing activities	(3,253,696)	(495,250)	(6,076,521)
Net increase (decrease) in cash, cash equivalents and restricted cash	(169,134)	184,551	100,339
Cash, cash equivalents and restricted cash at beginning of period	1,605,439	1,420,888	1,320,549
Cash, cash equivalents and restricted cash at end of period	1,436,305	1,605,439	1,420,888
Supplemental disclosure of cash flow information
Interest received during the period	4,892,301	4,568,991	4,155,723
Interest paid during the period	735,787	516,230	405,290
Income taxes paid during the period	320,513	375,116	494,205
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	90,072	72,408	121,292
Securitization of residential mortgage loans allocated to Available-for-sale investment securities	5,379	22,448	36,747
Securitization of residential mortgage loans allocated to capitalized servicing rights	83	$ 365	$ 422
Adoption of lease accounting standard - Right-of-use assets	393,877
Adoption of lease accounting standard - Other liabilities	398,810
Additions to right-of-use assets under operating leases	132,219
Series G Preferred Stock [Member]
Cash flows from financing activities
Proceeds from issuance of Series G preferred stock	$ 396,000