Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net income	$ 1,079,667	$ 1,066,246	$ 1,138,480
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	170,000	124,000	185,000
Depreciation and amortization of premises and equipment	99,019	96,496	91,469
Amortization of capitalized servicing rights	49,906	68,410	65,354
Amortization of core deposit and other intangible assets	26,424	33,824	46,912
Provision for deferred income taxes	396,596	92,848	139,785
Asset write-downs	9,029	6,593	17,918
Net gain on sales of assets	(67,759)	(6,859)	(127,890)
Net change in accrued interest receivable, payable	(46,338)	15,163	(10,523)
Net change in other accrued income and expense	(289,139)	(68,722)	71,523
Net change in loans originated for sale	323,330	(350,581)	(674,062)
Net change in trading account assets and liabilities	(8,327)	21,623	(11,642)
Net cash provided by operating activities	1,742,408	1,099,041	932,324
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale	5,654,850	16	1,081,802
Proceeds from sales of investment securities Other	183,892	23,445	13,172
Proceeds from maturities of investment securities Available for sale	2,392,331	998,413	1,034,564
Proceeds from maturities of investment securities Held to maturity	662,959	468,999	287,837
Purchases of investment securities Available for sale	(3,614,324)	(5,347,145)	(197,931)
Purchases of investment securities Held to maturity	(29,431)	(21,283)	(1,977,064)
Purchases of investment securities Other	(99,317)	(53,606)	(9,105)
Net (increase) decrease in loans and leases	(2,326,744)	(2,421,162)	123,120
Net (increase) decrease in interest-bearing deposits at banks	6,445,451	(4,819,729)	(1,521,193)
Capital expenditures, net	(81,936)	(73,161)	(129,563)
Net (increase) decrease in loan servicing advances	448,271	(484,689)	(1,004,923)
Acquisition, net of cash acquired, Bank and bank holding company	(1,932,596)
Other, net	10,876	19,531	95,706
Net cash provided (used) by investing activities	7,714,282	(11,710,371)	(2,203,578)
Cash flows from financing activities
Net increase in deposits	504,393	6,466,697	1,513,884
Net decrease in short-term borrowings	(2,167,405)	(67,779)	(814,027)
Proceeds from long-term borrowings	1,500,000	4,345,478	799,760
Payments on long-term borrowings	(8,912,474)	(426,275)	(261,212)
Dividends paid - common	(375,017)	(371,199)	(365,349)
Dividends paid - preferred	(81,270)	(70,234)	(53,450)
Proceeds from issuance of preferred stock		346,500
Other, net	69,766	88,565	137,967
Net cash provided (used) by financing activities	(9,462,007)	10,311,753	957,573
Net decrease in cash and cash equivalents	(5,317)	(299,577)	(313,681)
Cash and cash equivalents at beginning of year	1,373,357	1,672,934	1,986,615
Cash and cash equivalents at end of year	1,368,040	1,373,357	1,672,934
Supplemental disclosure of cash flow information
Interest received during the year	3,134,311	2,893,153	2,894,699
Interest paid during the year	400,329	257,553	301,734
Income taxes paid during the year	378,660	411,912	389,008
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	67,753	43,821	44,804
Acquisition of bank and bank holding company
Common stock issued	3,110,581
Common stock awards converted	28,243
Fair value of Assets acquired (noncash)	36,567,632
Liabilities assumed	31,496,212
Securitization of residential mortgage loans allocated to Available-for-sale investment securities	65,023	134,698	1,690,490
Securitization of residential mortgage loans allocated to Held to maturity investment securities			1,245,444
Securitization of residential mortgage loans allocated to capitalized servicing rights	$ 646	$ 1,760	$ 30,879