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

DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Managemen Add Info (Details Add Info)

DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Managemen Add Info (Details Add Info) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Derivative [Line Items]
Document Period End Date			Sep. 30, 2019
Derivative, Notional Amount	$ 24,702		$ 24,702		$ 4,877
Increase decrease to net interest income due to derivative adjustment	(16)	$ (11)	(44)	$ (25)
Asset conversion swaps - Receive Fixed - Generic
Derivative [Line Items]
Derivative, Notional Amount	$ 8,287		$ 8,287		$ 12
Derivative, Average Remaining Maturity	3 years 6 months		3 years 6 months		1 year 2 months 12 days
Fair Value	$ 106		$ 106		$ 0
Weighted-Average Rate Receive	1.69%		1.69%		2.20%
Weighted-Average Rate Pay	1.33%		1.33%		2.46%
Liability conversion swaps - Receive Fixed - Generic
Derivative [Line Items]
Derivative, Notional Amount	$ 7,540		$ 7,540		$ 4,865
Derivative, Average Remaining Maturity			2 years 6 months		2 years 7 months 6 days
Fair Value	$ 191		$ 191		$ 2
Weighted-Average Rate Receive	2.20%		2.20%		2.24%
Weighted-Average Rate Pay	2.08%		2.08%		2.54%
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 15,827		$ 15,827		$ 4,877
Derivative, Average Remaining Maturity	3 years				2 years 7 months 6 days
Fair Value	$ 297		$ 297		$ 2
Weighted-Average Rate Receive	1.93%		1.93%		2.24%
Weighted-Average Rate Pay	1.69%		1.69%		2.54%
Interest Rate Floor [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 8,875		$ 8,875
Derivative, Average Remaining Maturity			1 year 7 months 6 days
Fair Value	60		$ 60
Assigned [Member] \| Interest Rate Floor [Member]
Derivative [Line Items]
Derivative, Notional Amount	8,875		$ 8,875
Derivative, Average Remaining Maturity			1 year 7 months 6 days
Fair Value	$ 60		$ 60
Unassigned [Member] \| Interest Rate Floor [Member]
Derivative [Line Items]
Derivative, Average Remaining Maturity			0 years