Consolidated Balance Sheet - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 1,420,888	$ 1,320,549
Interest-bearing deposits at banks	5,078,903	5,000,638
Trading account	132,909	323,867
Investment securities (includes pledged securities that can be sold or repledged of $487,151 at December 31, 2017; $1,203,473 at December 31, 2016)
Available for sale (cost: $10,938,796 at December 31, 2017; $13,338,301 at December 31, 2016)	10,896,284	13,332,072
Held to maturity (fair value: $3,341,762 at December 31, 2017; $2,451,222 at December 31, 2016)	3,353,213	2,457,278
Other (fair value: $415,028 at December 31, 2017; $461,118 at December 31, 2016)	415,028	461,118
Total investment securities	14,664,525	16,250,468
Loans and leases	88,242,886	91,101,677
Unearned discount	(253,903)	(248,261)
Loans and leases, net of unearned discount	87,988,983	90,853,416
Allowance for credit losses	(1,017,198)	(988,997)
Loans and leases, net	86,971,785	89,864,419
Premises and equipment	646,451	675,263
Goodwill	4,593,112	4,593,112
Core deposit and other intangible assets	71,589	97,655
Accrued interest and other assets	5,013,325	5,323,235
Total assets	118,593,487	123,449,206
Liabilities
Noninterest-bearing deposits	33,975,180	32,813,896
Savings and interest-checking deposits	51,698,008	52,346,207
Time deposits	6,580,962	10,131,846
Deposits at Cayman Islands office	177,996	201,927
Total deposits	92,432,146	95,493,876
Short-term borrowings	175,099	163,442
Accrued interest and other liabilities	1,593,993	1,811,431
Long-term borrowings	8,141,430	9,493,835
Total liabilities	102,342,668	106,962,584
Shareholders' equity
Preferred stock, $1.00 par, 1,000,000 shares authorized; Issued and outstanding: Liquidation preference of $1,000 per share: 731,500 shares at December 31, 2016 and December 31, 2015; Liquidation preference of $10,000 per share: 50,000 shares at December 31, 2016 and December 31, 2015	1,231,500	1,231,500
Common stock, $.50 par, 250,000,000 shares authorized, 159,945,678 shares issued at December 31, 2016; 159,563,512 shares issued at December 31, 2015	79,909	79,973
Common stock issuable, 32,403 shares at December 31, 2016; 36,644 shares at December 31, 2015	1,847	2,145
Additional paid-in capital	6,590,855	6,676,948
Retained earnings	10,164,804	9,222,488
Accumulated other comprehensive income (loss), net	(363,814)	(294,636)
Treasury stock — common, at cost — 9,733,115 shares at December 31, 2017; 3,764,742 shares at December 31, 2016	(1,454,282)	(431,796)
Total shareholders’ equity	16,250,819	16,486,622
Total liabilities and shareholders’ equity	$ 118,593,487	$ 123,449,206