Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net income	$ 1,353,152	$ 1,929,149	$ 1,918,080
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	800,000	176,000	132,000
Depreciation and amortization of premises and equipment	220,598	209,937	104,864
Amortization of capitalized servicing rights	84,821	71,888	49,619
Amortization of core deposit and other intangible assets	14,869	19,490	24,522
Provision for deferred income taxes	(31,291)	57,548	15,857
Asset write-downs	21,014	7,701	24,774
Net (gain) loss on sales of assets	(19,441)	31,526	(23,503)
Net change in accrued interest receivable, payable	(132,252)	30,923	(7,162)
Net change in other accrued income and expense	(418,752)	75,930	13,436
Net change in loans originated for sale	(542,078)	130,230	(150,695)
Net change in trading account assets and liabilities	(561,453)	(382,767)	(11,940)
Net cash provided by operating activities	789,187	2,357,555	2,089,852
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale		107	418
Proceeds from sales of investment securities equity and other	67,036	1,169,876	650,858
Proceeds from maturities of investment securities Available for sale	1,614,557	2,621,603	1,997,263
Proceeds from maturities of investment securities Held to maturity	911,555	1,162,820	478,172
Purchases of investment securities Available for sale	(7,581)	(28,120)	(12,494)
Purchases of investment securities Held to maturity	(11,993)	(495,277)	(444,703)
Purchases of investment securities equity and other	(29,004)	(979,734)	(834,856)
Net increase in loans and leases	(7,231,694)	(2,795,263)	(475,895)
Net increase (decrease) in interest-bearing deposits at banks	(16,473,656)	915,043	(3,026,294)
Capital expenditures, net	(172,289)	(178,049)	(97,676)
Net (increase) decrease in loan servicing advances	(754,823)	(470,078)	307,252
Other, net	67,411	(195,921)	47,904
Net cash provided (used) by investing activities	(22,020,481)	727,007	(1,410,051)
Cash flows from financing activities
Net increase (decrease) in deposits	25,037,167	4,616,082	(2,272,505)
Net increase (decrease) in short-term borrowings	(2,881)	(4,336,015)	4,223,279
Proceeds from long-term borrowings			1,773,189
Payments on long-term borrowings	(2,665,023)	(1,553,493)	(1,459,081)
Purchases of treasury stock	(373,750)	(1,349,785)	(2,194,396)
Dividends paid — common	(568,112)	(552,138)	(510,382)
Dividends paid — preferred	(68,256)	(67,454)	(72,521)
Redemption of Series A and Series C preferred stock		(381,500)
Other, net	(11,413)	(25,393)	17,167
Net cash provided (used) by financing activities	21,347,732	(3,253,696)	(495,250)
Net increase (decrease) in cash, cash equivalents and restricted cash	116,438	(169,134)	184,551
Cash, cash equivalents and restricted cash at beginning of period	1,436,305	1,605,439	1,420,888
Cash, cash equivalents and restricted cash at end of period	1,552,743	1,436,305	1,605,439
Supplemental disclosure of cash flow information
Interest received during the period	4,135,990	4,892,301	4,568,991
Interest paid during the period	372,291	735,787	516,230
Income taxes paid during the period	275,558	320,513	375,116
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	20,646	90,072	72,408
Securitization of residential mortgage loans allocated to Available-for-sale investment securities		5,379	22,448
Securitization of residential mortgage loans allocated to capitalized servicing rights		83	$ 365
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	$ 70,754	132,219
Series G Preferred Stock [Member]
Cash flows from financing activities
Proceeds from issuance of Series G preferred stock		$ 396,000