Fair Values of Assets and Liabilities (Details 5) (USD $)							9 Months Ended
	Sep. 30, 2011		Dec. 31, 2010		Sep. 30, 2010		Sep. 30, 2011 Nonrecurring Basis [Member]	Sep. 30, 2011 Nonrecurring Basis [Member] Level 1 [Member]	Sep. 30, 2011 Nonrecurring Basis [Member] Level 2 [Member]	Sep. 30, 2011 Nonrecurring Basis [Member] Level 3 [Member]	Sep. 30, 2011 Carrying Amount [Member]	Dec. 31, 2010 Carrying Amount [Member]	Sep. 30, 2010 Carrying Amount [Member]	Sep. 30, 2011 Fair Value [Member]	Dec. 31, 2010 Fair Value [Member]	Sep. 30, 2010 Fair Value [Member]
Assets measured at fair value on a nonrecurring basis
Fair value, Impaired loans							$ 91,000,000	$ 0	$ 0	$ 91,000,000
Gain/(Losses), Impaired loans							25,500,000
Fair value, Accrued income and other assets							38,000,000	0	0	38,000,000
Gain/(Losses), Accrued income and other assets							(1,800,000)
Financial Assets:
Cash and short-term assets											2,295,730,000	982,926,000	1,413,466,000	2,295,730,000	982,926,000	1,413,466,000
Trading account securities	85,711,000		185,404,000		138,677,000						85,711,000	185,404,000	138,677,000	85,711,000	185,404,000	138,677,000
Loans held for sale	334,606,000	[1]	793,285,000	[1]	744,439,000	[1]					334,606,000	793,285,000	744,439,000	334,606,000	793,285,000	744,439,000
Available-for-sale and other securities	8,713,530,000		9,895,244,000		9,723,558,000						8,713,530,000	9,895,244,000	9,723,558,000	8,713,530,000	9,895,244,000	9,723,558,000
Held-to-maturity securities, Total	658,250,000		0		0						658,250,000	0	0	682,897,000	0	0
Net loans and direct financing leases	37,992,184,000		36,857,499,000		36,164,235,000						37,992,184,000	36,857,499,000	36,164,235,000	36,655,676,000	35,403,910,000	34,894,220,000
Derivatives											73,824,000	346,133,000	434,288,000	73,824,000	346,133,000	434,288,000
Financial Liabilities:
Deposits	43,219,727,000		41,853,898,000		41,072,371,000						(43,219,727,000)	(41,853,898,000)	(41,072,371,000)	(43,368,155,000)	(41,993,567,000)	(41,323,675,000)
Short-term borrowings	2,224,986,000		2,040,732,000		1,859,134,000						(2,224,986,000)	(2,040,732,000)	(1,859,134,000)	(2,200,121,000)	(1,982,545,000)	(1,854,637,000)
Federal Home Loan Bank advances	14,157,000		172,519,000		23,643,000						(14,157,000)	(172,519,000)	(23,643,000)	(14,157,000)	(172,519,000)	(23,843,000)
Other long term debt	1,421,518,000	[2]	2,144,092,000	[2]	2,393,071,000	[2]					(1,421,518,000)	(2,144,092,000)	(2,393,071,000)	(1,426,460,000)	(2,157,358,000)	(2,400,942,000)
Subordinated notes	1,537,293,000		1,497,216,000		1,202,568,000						(1,537,293,000)	(1,497,216,000)	(1,202,568,000)	(1,423,105,000)	(1,377,851,000)	(1,047,875,000)
Derivatives											$ (295,872,000)	$ (239,240,000)	$ (306,803,000)	$ (295,872,000)	$ (239,240,000)	$ (306,803,000)

[1] Amounts represent loans for which Huntington has elected the fair value option.

[2] Amounts represent certain assets and liabilities of a consolidated VIE for which Huntington has elected the fair value option.