Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
OPERATING ACTIVITIES
Net income	$ 210,955	$ 230,718
Adjustments to reconcile net income to cash provided by operating activities:
Provision (credit) for loan and lease losses	48,907	16,948
Deferred tax expense (benefit)	17,774	5,126
Net change in current taxes	12,122	(23,826)
Depreciation	53,806	50,574
Net (decrease) increase in accrued interest payable	(4,012)	10,485
Net (increase) decrease in income earned not collected	(51,784)	(1,747)
Contribution to pension plans	(100,000)	0
Contribution to pension plans	(33,547)	(5,719)
Marketable equity securities gain (loss), net	(13,162)	(14,472)
Origination of loans held for sale	(503,190)	(328,481)
Origination of loans held for sale	474,153	326,640
Gain on sale of loans held for sale	(15,578)	(6,395)
Net writedowns/losses on other real estate	2,475	1,417
Net accretion of premiums and discounts	20,889	(16,491)
Amortization of intangible assets	12,464	12,019
Net change in mortgage servicing rights	357	(2,283)
Net change in other assets	(17,459)	(12,375)
Net change in other liabilities	(14,380)	(22,373)
Net cash provided by operating activities	100,790	219,765
INVESTING ACTIVITIES
Net increase in loans outstanding	(3,488,854)	(168,572)
Purchases of investment securities available for sale	(5,659,704)	(1,553,876)
Purchases of investment securities held to maturity	(803,307)	(183,288)
Purchases of marketable equity securities	(331,952)	(14,108)
Proceeds from maturities/calls of investment securities held to maturity	57,057	190,644
Proceeds from maturities/calls of investment securities available for sale	1,139,291	1,061,895
Proceeds from sales of investment securities available for sale	3,122,454	610,787
Proceeds from sales of marketable equity securities	313,131	10,694
Net increase in overnight investments	(1,964,602)	(840,371)
Proceeds from sales of portfolio loans	0	24,247
Repayment of FDIC Shared-Loss Payable	(99,468)	0
Proceeds from sales of other real estate	9,263	11,884
Proceeds from sales of premises and equipment	37	75
Purchases of premises and equipment	(62,721)	(54,873)
Business acquisitions, net of cash acquired	(59,999)	(73,792)
Net cash used in investing activities	(7,829,374)	(978,654)
FINANCING ACTIVITIES
Net decrease in time deposits	(623,833)	291,930
Net increase in demand and other interest-bearing deposits	7,649,120	762,021
Net decrease in short-term borrowings	2,043	(109,109)
Repayments of Other Long-term Debt	(75,908)	(33,008)
Origination of long-term obligations	400,000	0
Proceeds from Debt, Net of Issuance Costs	345,850	0
Proceeds from issuance of preferred stock, net of issuance costs	339,937
Proceeds from Issuance of Preferred Stock and Preference Stock	345,000	0
Repurchase of common stock	(282,923)	(186,995)
Cash dividends paid	(13,188)	(9,243)
Net cash (used in) provided by financing activities	7,741,098	715,596
Change in cash and due from banks	12,514	(43,293)
Cash and due from banks at beginning of period	376,719	327,440
Cash and due from banks at end of period	389,233	284,147
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Transfers of loans to other real estate	7,138	5,710
Dividends declared but not paid	4,007	4,410
Unsettled maturities of investment securities	0	150,122
Unsettled purchases of investment securities	0	1,126
Net reclassification of portfolio loans (to) from loans held for sale	(3,027)	23,343
Transfers of premises and equipment to other real estate	2,046	2,184
Unsettled common stock repurchases	$ 3,772	$ 3,535