CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities
Net income	$ 373,292	$ 131,712
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Reversal of) provision for credit losses	(43,173)	300,573
Depreciation, amortization, and accretion, net	84,091	49,921
Deferred income tax expense (benefit)	25,111	(54,741)
Originations of loans held for sale	(2,042,076)	(1,806,895)
Proceeds from sales and payments on loans held for sale	2,078,089	1,045,342
Gain on sales of loans held for sale, net	(27,502)	(25,785)
Increase in other assets	(24,873)	(1,631,678)
(Decrease) increase in other liabilities	(1,554)	1,175,881
Investment securities losses (gains), net	1,990	(78,144)
Share-based compensation expense	13,131	8,920
Other	0	1,904
Net cash provided by (used in) operating activities	436,526	(882,990)
Investing Activities
Proceeds from maturities and principal collections of investment securities available for sale	1,616,397	930,004
Proceeds from sales of investment securities available for sale	223,977	2,682,861
Purchases of investment securities available for sale	(3,476,929)	(3,890,074)
Proceeds from sales of loans	86,650	17,969
Purchases of loans	(1,041,602)	0
Net decrease (increase) in loans	928,084	(2,748,040)
Net (purchases) redemptions of Federal Home Loan Bank stock	(1,200)	71,272
Net purchases of Federal Reserve Bank stock	(954)	(454)
Net proceeds from settlement (purchases) of bank-owned life insurance policies	6,264	(249,273)
Net increase in premises, equipment and software	(12,419)	(20,186)
Other	4,141	33,514
Net cash used in investing activities	(1,667,591)	(3,172,407)
Financing Activities
Net increase in deposits	480,391	5,788,189
Net (decrease) increase in federal funds purchased and securities sold under repurchase agreements	(33,135)	59,886
Net decrease in other short-term borrowings	(7,717)	(1,453,560)
Repayments and redemption of long-term debt	0	(1,076,759)
Proceeds from issuance of long-term debt, net	0	1,248,441
Dividends paid to common shareholders	(97,927)	(92,741)
Dividends paid to preferred shareholders	(16,581)	(16,581)
Repurchases of common stock	(92,507)	(16,246)
Issuances, net of taxes paid, under equity compensation plans	8,300	(925)
Net cash provided by financing activities	240,824	4,439,704
(Decrease) increase in cash and cash equivalents including restricted cash	(990,241)	384,307
Cash, cash equivalents, and restricted cash, at beginning of period	4,252,917	1,186,918
Cash, cash equivalents, and restricted cash at end of period	3,262,676	1,571,225
Supplemental Disclosures:
Income taxes paid	115,282	257
Interest paid	78,772	194,687
Non-cash Activities
Premises and equipment transferred to other assets held for sale	3,864	5,837
Securities purchased during the period but settled after period-end	48,795	0
Loans foreclosed and transferred to other real estate	801	2,013
Loans transferred to other loans held for sale at fair value	0	933,353
Dividends declared on common stock during the period but paid after period-end	48,651	48,612
Dividends declared on preferred stock during the period but paid after period-end	$ 5,141	$ 5,141