Huntington Bancshares Incorporated Quarterly report pursuant to Section 13 or 15(d)

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Schedule of Amortized Cost, Fair Value, and Gross Unrealized Gains and Losses (Details)

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Schedule of Amortized Cost, Fair Value, and Gross Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 15,611,683	$ 15,776,855
Unrealized Gross Gains	44,395	47,626
Unrealized Gross Losses	(203,017)	(261,644)
Fair Value	15,453,061	15,562,837
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,256	5,480
Unrealized Gross Gains	4	17
Unrealized Gross Losses	0	0
Fair Value	11,260	5,497
Federal agencies: Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,786,058	10,851,461
Unrealized Gross Gains	5,851	12,548
Unrealized Gross Losses	(152,159)	(190,667)
Fair Value	10,639,750	10,673,342
Federal agencies, Other agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	95,785	73,012
Unrealized Gross Gains	722	536
Unrealized Gross Losses	(56)	(6)
Fair Value	96,451	73,542
Total U.S. Treasury, Federal agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,893,099	10,929,953
Unrealized Gross Gains	6,577	13,101
Unrealized Gross Losses	(152,215)	(190,673)
Fair Value	10,747,461	10,752,381
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,429,829	3,260,428
Unrealized Gross Gains	31,043	28,431
Unrealized Gross Losses	(34,763)	(38,802)
Fair Value	3,426,109	3,250,057
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	568,806	824,124
Unrealized Gross Gains	2,409	1,492
Unrealized Gross Losses	(16,024)	(32,135)
Fair Value	555,191	793,481
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	121,703	194,537
Unrealized Gross Gains	3,927	4,161
Unrealized Gross Losses	(1)	(15)
Fair Value	125,629	198,683
Other securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	598,246	567,813
Unrealized Gross Gains	439	441
Unrealized Gross Losses	(14)	(19)
Fair Value	$ 598,671	$ 568,235