Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net income	$ 192,470	$ 227,472
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for credit losses	50,879	27,874
Share-based compensation expense	17,762	14,040
Depreciation and amortization	207,954	153,018
Provision (benefit) for deferred income taxes	(27,732)	33,409
Net gains on sales of assets	(46,966)	(28,977)
Proceeds from sales of loans and leases held-for-sale	512,051	264,970
Originations of loans and leases held-for-sale, net of repayments	(548,371)	(271,793)
Impairment of loan servicing rights	4,520	0
Net change in other assets	(188,081)	21,984
Net change in other liabilities	16,229	(1,849)
Other, net	(34,793)	(29,668)
Net cash provided by (used in) operating activities	155,922	410,480
Cash flows from investing activities
Proceeds from sales of investment securities available-for-sale	1,993,274	0
Proceeds from maturities of and principal collected on investment securities available-for-sale	398,989	120,183
Purchases of investment securities available-for-sale	(1,424,344)	(919,645)
Proceeds from maturities of and principal collected on investment securities held-to-maturity	11,945	11,259
Purchases of investment securities held-to-maturity	(4,029)	(2,187)
Redemption of Federal Home Loan Bank stock	162,011	201,001
Purchases of Federal Home Loan Bank stock	(142,000)	(199,000)
Proceeds from sales of loans and leases	566,880	675,164
Loan and lease originations and purchases, net of principal collected	(674,459)	735,840
Proceeds from sales of other assets	82,970	58,879
Purchases of premises and equipment and lease equipment	(108,404)	(903,394)
Net cash acquired (paid) in business combination	975,014	0
Other, net	(6,743)	15,151
Net cash provided by (used in) investing activities	1,831,104	(206,749)
Cash flows from financing activities
Net change in deposits	(15,296)	163,442
Net change in short-term borrowings	(17,292)	2,451
Proceeds from long-term borrowings	2,799,986	7,043,458
Payments on long-term borrowings	(3,838,454)	(7,118,690)
Payments on liabilities related to acquisition and portfolio purchase	(1,000)	0
Redemption of Series B preferred stock	0	(100,000)
Repurchases of common stock	(58,804)	(149,912)
Common shares sold to TCF employee benefit plans	0	715
Dividends paid on preferred stock	(7,481)	(9,094)
Dividends paid on common stock	(102,368)	(74,916)
Exercise of stock options	0	(997)
Payments related to tax-withholding upon conversion of share-based awards	(5,813)	(6,563)
Net investment by (distribution to) non-controlling interest	(4,547)	(5,439)
Net cash provided by (used in) financing activities	(1,251,069)	(255,545)
Net change in cash and due from banks	735,957	(51,814)
Cash and cash equivalents at beginning of period	587,057	621,782
Cash and cash equivalents at end of period	1,323,014	569,968
Cash paid (received) for:
Interest on deposits and borrowings	192,793	99,336
Income taxes, net	10,367	(21,035)
Noncash activities:
Transfer of loans and leases to other assets	73,314	77,704
Transfer of loans and leases from held for investment to held for sale, net	$ 1,837,445	$ 644,488