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

DERIVATIVE FINANCIAL INSTRUMENTS - Mortgage Banking Activities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Derivative assets:
Total derivative assets	$ 454		$ 454		$ 322
Derivative liabilities:
Total derivative liabilities	(406)		(406)		(331)
Interest rate lock agreements
Derivative assets:
Total derivative assets	8		8		6
Derivative liabilities:
Total derivative liabilities	0		0		0
Forward trades and options
Derivative assets:
Total derivative assets	0		0		1
Derivative liabilities:
Total derivative liabilities	5		5		0
Derivative used in Mortgage Banking Activities
Derivatives, Fair Value [Line Items]
Gains losses related to derivative instruments Included in Mortgage securities	0	$ 2	(8)	$ 1
Derivative assets:
Total derivative assets	8		8		7
Derivative liabilities:
Total derivative liabilities	$ 5		$ 5		$ 0