Regulatory Matters (Information On The Capital Ratios) (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividends paid by Webster Bank	$ 80,000,000	$ 70,000,000
Trust Preferred Securities Included in Tier One Capital	75,000,000		75,000,000
Webster Financial Corporation [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital, Actual Amount	2,060,208,000		1,965,171,000
Total risk-based capital, Actual Ratio	14.20%		14.20%
Total risk-based capital, Minimum Amount	1,163,206,000		1,106,203,000
Total risk-based capital, Capital Requirements Ratio	8.00%		8.00%
Total risk-based capital, Well Capitalized Amount	1,454,008,000		1,382,754,000
Total risk-based capital, Well Capitalized Ratio	10.00%		10.00%
Tier 1 capital, Actual Amount	1,898,704,000		1,807,642,000
Tier 1 capital, Actual Ratio	13.10%		13.10%
Tier 1 capital, Minimum Amount	581,603,000		553,101,000
Tier 1 capital, Capital Requirements Ratio	4.00%		4.00%
Tier 1 capital, Well Capitalized Amount	872,405,000		829,652,000
Tier 1 capital, Well Capitalized Ratio	6.00%		6.00%
Tier 1 leverage capital ratio, Actual Amount	1,898,704,000		1,807,642,000
Tier 1 leverage capital ratio, Actual Ratio	9.00%		9.00%
Tier 1 leverage capital ratio, Minimum Amount	840,727,000		801,535,000
Tier 1 leverage capital ratio, Capital Requirements Ratio	4.00%		4.00%
Tier 1 leverage capital ratio, Well Capitalized Amount	1,050,909,000		1,001,919,000
Tier 1 leverage capital ratio, Well Capitalized Ratio	5.00%		5.00%
Webster Bank N.A. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital, Actual Amount	1,901,130,000		1,815,423,000
Total risk-based capital, Actual Ratio	13.10%		13.20%
Total risk-based capital, Minimum Amount	1,161,080,000		1,104,200,000
Total risk-based capital, Capital Requirements Ratio	8.00%		8.00%
Total risk-based capital, Well Capitalized Amount	1,451,350,000		1,380,250,000
Total risk-based capital, Well Capitalized Ratio	10.00%		10.00%
Tier 1 capital, Actual Amount	1,739,626,000		1,658,466,000
Tier 1 capital, Actual Ratio	12.00%		12.00%
Tier 1 capital, Minimum Amount	580,540,000		552,100,000
Tier 1 capital, Capital Requirements Ratio	4.00%		4.00%
Tier 1 capital, Well Capitalized Amount	870,810,000		828,150,000
Tier 1 capital, Well Capitalized Ratio	6.00%		6.00%
Tier 1 leverage capital ratio, Actual Amount	1,739,626,000		1,658,466,000
Tier 1 leverage capital ratio, Actual Ratio	8.30%		8.30%
Tier 1 leverage capital ratio, Minimum Amount	839,728,000		800,063,000
Tier 1 leverage capital ratio, Capital Requirements Ratio	4.00%		4.00%
Tier 1 leverage capital ratio, Well Capitalized Amount	$ 1,049,660,000		$ 1,000,079,000
Tier 1 leverage capital ratio, Well Capitalized Ratio	5.00%		5.00%