Regulatory Matters (Schedule Of Information On The Capital Ratios) (Details) (USD $)	3 Months Ended		12 Months Ended			12 Months Ended
	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2011 Webster Financial Corporation [Member]	Dec. 31, 2010 Webster Financial Corporation [Member]		Dec. 31, 2011 Webster Bank, N.A. [Member]	Dec. 31, 2010 Webster Bank, N.A. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital, Actual Amount			$ 1,766,468,000	$ 1,645,856,000	[1]	$ 1,681,769,000	$ 1,678,090,000	[1]
Total risk-based capital, Actual Ratio		12.00%	14.60%	13.90%	[1]	14.00%	14.30%	[1]
Total risk-based capital, Capital Requirements Amount			967,017,000	944,470,000	[1]	964,184,000	941,019,000	[1]
Total risk-based capital, Capital Requirements Ratio			8.00%	8.00%	[1]	8.00%	8.00%	[1]
Total risk-based capital, Well Capitalized Amount			1,208,772,000	1,180,587,000	[1]	1,205,230,000	1,176,273,000	[1]
Total risk-based capital, Well Capitalized Ratio			10.00%	10.00%	[1]	10.00%	10.00%	[1]
Tier 1 capital, Actual Amount			1,577,991,000	1,424,652,000	[1]	1,494,529,000	1,457,794,000	[1]
Tier 1 capital, Actual Ratio			13.10%	12.10%	[1]	12.40%	12.40%	[1]
Tier 1 capital, Capital Requirements Amount			483,509,000	472,235,000	[1]	482,092,000	470,509,000	[1]
Tier 1 capital, Capital Requirements Ratio			4.00%	4.00%	[1]	4.00%	4.00%	[1]
Tier 1 capital, Well Capitalized Amount			725,263,000	708,352,000	[1]	723,138,000	705,764,000	[1]
Tier 1 capital, Well Capitalized Ratio			6.00%	6.00%	[1]	6.00%	6.00%	[1]
Tier 1 leverage capital ratio, Actual Amount			1,577,991,000	1,424,652,000	[1]	1,494,529,000	1,457,794,000	[1]
Tier 1 leverage capital ratio, Actual Ratio		7.50%	8.90%	8.30%	[1]	8.40%	8.50%	[1]
Tier 1 leverage capital ratio, Capital Requirements Amount			713,319,000	685,896,000	[1]	711,572,000	684,060,000	[1]
Tier 1 leverage capital ratio, Capital Requirements Ratio			4.00%	4.00%	[1]	4.00%	4.00%	[1]
Tier 1 leverage capital ratio, Well Capitalized Amount			891,648,000	857,370,000	[1]	889,466,000	855,076,000	[1]
Tier 1 leverage capital ratio, Well Capitalized Ratio			5.00%	5.00%	[1]	5.00%	5.00%	[1]
Value down-streamed to improve the capital position	100,000,000
Tier 1 capital, trust preferred securities			209,900,000
Dividends paid by Webster Bank						$ 170,000,000

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