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

FAIR VALUES OF ASSETS AND LIABILITIES - Level 3 Classification of Gains/Losses (Details)

FAIR VALUES OF ASSETS AND LIABILITIES - Level 3 Classification of Gains/Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	$ 51	$ (47)
Mortgage banking income	(51)	47
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings	51	(47)
Fair Value Assets Measured On Recurring Basis Gain Loss Included In Interest and fee income		0
Derivative Financial Instruments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Mortgage banking income	(8)	(53)
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings	(8)	(53)
Fair Value Assets Measured On Recurring Basis Gain Loss Included In Interest and fee income		0
Municipal securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	(1)
Mortgage banking income		0
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings		(1)
Fair Value Assets Measured On Recurring Basis Gain Loss Included In Interest and fee income		(1)
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	$ 0	$ 0