Acquisition Of Whitney Holding Corporation (Assets Purchased And The Liabilities Assumed And The Adjustments To Fair Value) (Details) (USD $)	9 Months Ended						9 Months Ended
	Sep. 30, 2011	Jun. 04, 2011	Dec. 31, 2010	Sep. 30, 2010	Jul. 04, 2011 Whitney Holding Corporation [Member]		Sep. 30, 2011 Credit Card Relationships [Member]	Sep. 30, 2011 Trust [Member]
Business Acquisition [Line Items]
Cash and cash equivalents					$ 957,000,000
Loans held for sale	64,545,000		21,866,000		57,000,000
Securities	4,604,835,000		1,488,885,000		2,635,000,000
Loans and leases					6,456,000,000
Property and equipment	524,265,000		209,919,000		284,000,000
Other intangible assets					266,000,000	[1]
Other assets					580,000,000
Total assets	19,415,689,000		8,138,327,000	8,239,362,000	11,235,000,000
Deposits	15,292,209,000		6,775,719,000		9,182,000,000
Borrowings					776,000,000
Other liabilities	273,825,000		126,829,000		175,000,000
Total liabilities	16,989,027,000		7,281,779,000		10,133,000,000
Net identifiable assets acquired	11,700,000,000				1,102,000,000
Goodwill	629,688,000			61,631,000	514,000,000	[2]
Net assets acquired					1,616,000,000
Hancock Holding Company common shares issued					41,000,000
Purchase price per share of the Company's common stock					$ 32.04	[3]
Company common stock issued and cash exchanged for fractional shares					1,307,000,000
Stock options converted					1,000,000
Cash paid for TARP preferred stock and warrants					308,000,000
Fair value of total consideration transferred		1,600,000,000			1,616,000,000
Goodwill expected to be deductible	$ 0
CDI intangible assets, amortization life, minimum (in years)	13
CDI intangible assets, amortization life, maximum (in years)	15
Amortization life, years							17	12

[1] Intangible assets consists of core deposit intangible of $189 million, trade name of $54 million, trust relationships of $11 million, and credit card relationships of $11 million. The amortization life is 13 - 15 years for the CDI intangible asset; 17 years for credit card relationships and 12 years for trust. They will be amortized on an accelerated basis.

[2] No goodwill is expected to be deductible for federal income tax purposes. The goodwill will be primarily allocated to the Whitney Bank segment.

[3] The value of the shares of common stock exchanged with Whitney shareholders was based upon the closing price of the Company's common stock at June 3, 2011, the last traded day prior to the date of acquisition.