Parent Company Information (Components Of Condensed Cash Flow The Parent Company) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Income from discontinued operations, net of tax									$ 1,995	[1]	$ 94	[1],[2]	$ 302	[1],[2]
Income (loss) from continuing operations	31,862	[3]	22,623	[3]	16,879	[3]	800	[3]	149,383		72,164		(77,189)
Net cash (used for) provided by operating activities									266,522		337,046		114,089
(Increase) decrease in interest-bearing deposits									(43,251)		337,499		(368,156)
Purchases of available for sale securities									(1,305,583)		(1,297,512)		(1,597,782)
Proceeds from maturities and principal payments of available for sale securities									545,933		608,710		305,168
Proceeds from sales of available for sale securities									278,757		416,474		433,248
Net decrease in loan									(338,037)		(173,635)		614,364
Net cash provided by (used for) investing activities									(771,709)		(517,841)		(465,976)
Redemption of subsidiary preferred stock									(9,577)
Repayment of long-term debt									(22,689)				(15,927)
Conversion of Series A preferred stock													(60,935)
Cash dividends paid to common shareholders									(13,978)		(3,133)		(2,443)
Cash dividends paid to preferred shareholders									(2,460)		(17,223)		(31,670)
Exercise of stock options									213		378		21
Warburg investment											36,440		116,187
Proceeds from issuance of common stock									689		118,359		1,031
Common stock repurchased									(1,670)		(1,654)		(792)
Common stock warrants repurchased									16,285
Net cash (used for) provided by financing activities									539,300		169,366		263,561
Operating activities									1,995		94		302
Net cash provided by discontinued operations									1,995		94		302
Increase (decrease) in cash and due from banks									36,108		(11,335)		(88,024)
Parent Company [Member]
Net income (loss) attributable to Webster Financial Corporation									151,379		72,255	[4]	(76,909)	[4]
Income from discontinued operations, net of tax									1,995		94	[4]	302	[4]
Income (loss) from continuing operations									149,384		72,161	[4]	(77,211)	[4]
Equity in undistributed earnings of subsidiaries and associated companies									(178,827)		(79,131)	[4]	63,583	[4]
Other, net									27,325		(30,163)	[4]	21,818	[4]
Net cash (used for) provided by operating activities									(2,118)		(37,133)	[4]	8,190	[4]
(Increase) decrease in interest-bearing deposits									(120,133)		400,688	[4]	60,378	[4]
Purchases of available for sale securities									(3,714)		(500)	[4]	(100)	[4]
Proceeds from maturities and principal payments of available for sale securities									575
Proceeds from sales of available for sale securities									2,353		750	[4]	17,371	[4]
Net decrease in loan									13,000				5,000	[4]
Dividend from subsidiary									170,000
Capital contribution to subsidiary											(100,000)	[4]	(100,000)	[4]
Net cash provided by (used for) investing activities									62,081		300,938	[4]	(17,351)	[4]
Repayment of other borrowings													(13,180)	[4]
Repayment of long-term debt									(22,689)
Redemption of preferred stock	(400,000)	[4]									(400,000)	[4]
Conversion of Series A preferred stock													(60,935)	[4]
Cash dividends paid to common shareholders									(13,978)		(3,133)	[4]	(2,443)	[4]
Cash dividends paid to preferred shareholders									(2,460)		(17,223)	[4]	(31,670)	[4]
Exercise of stock options									213		378	[4]	21	[4]
Warburg investment											36,440	[4]	116,187	[4]
Proceeds from issuance of common stock									689		118,359	[4]	1,031	[4]
Common stock repurchased									(1,670)		(1,654)	[4]	(792)	[4]
Common stock warrants repurchased									(16,285)
Net cash (used for) provided by financing activities									(56,180)		(266,833)	[4]	8,219	[4]
Operating activities									1,995		94	[4]	302	[4]
Net cash provided by discontinued operations									1,995		94	[4]	302	[4]
Increase (decrease) in cash and due from banks									5,778		(2,934)	[4]	(640)	[4]
Cash and cash equivalents at beginning of year							12,559	[4]	9,625	[4]	12,559	[4]	13,199	[4]
Cash and cash equivalents at end of year	$ 9,625	[4]							$ 15,403		$ 9,625	[4]	$ 12,559	[4]

[1] Reclassified to conform to the 2011 presentation. The consumer liquidating portfolio was not established as a separate operating unit until April 2010, as part of the presentation for 2010, the consumer liquidating portfolio for the three months ended March 31, 2010 has not been reclassified to conform to the 2011 presentation. As part of the presentation for 2009, the consumer liquidating portfolio for the year ended December 31, 2009 has not been reclassified to conform to the 2011 presentation, and total assets at December 31, 2009 has not been reclassified to conform to the 2011 and 2010 presentations.

[2] Certain previously reported information has been corrected to reflect the deferment of certain commercial loan fees. For more information refer to Note 1

[3] Certain previously reported information has been corrected to reflect the deferrment of certain commercial loan fees. For more information refer to Note 1.

[4] Certain previously reported information has been corrected to reflect the deferment of certain commercial loan fees.