Loans - Consumer, Excluding Credit Card Loan Portfolio, Loan Modifications, Nature and Extent of Modifications (Details) - Consumer, excluding credit card - loan	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Financing Receivable, Impaired [Line Items]
Concession granted - Interest rate reduction	68.00%	72.00%
Concession granted - Term of payment extension	90.00%	83.00%
Concession granted - Principal and/or interest deferred	18.00%	30.00%
Concession granted - principal forgiveness	14.00%	18.00%
Concession granted - other	6.00%	5.00%
Percentage, sum of items by type, may exceed	100.00%
Home equity
Financing Receivable, Impaired [Line Items]
Concession granted - Interest rate reduction	66.00%	76.00%
Concession granted - Term of payment extension	90.00%	84.00%
Concession granted - Principal and/or interest deferred	16.00%	29.00%
Concession granted - principal forgiveness	9.00%	5.00%
Concession granted - other	1.00%	0.00%
Residential Mortgage
Financing Receivable, Impaired [Line Items]
Concession granted - Interest rate reduction	74.00%	68.00%
Concession granted - Term of payment extension	89.00%	82.00%
Concession granted - Principal and/or interest deferred	23.00%	30.00%
Concession granted - principal forgiveness	25.00%	30.00%
Concession granted - other	18.00%	10.00%
Trial Modification
Financing Receivable, Impaired [Line Items]
Number of contract modifications	1,629	1,177
Trial Modification | Home equity
Financing Receivable, Impaired [Line Items]
Number of contract modifications	1,049	510
Trial Modification | Residential Mortgage
Financing Receivable, Impaired [Line Items]
Number of contract modifications	580	667
Permanent Modification
Financing Receivable, Impaired [Line Items]
Number of contract modifications	2,424	1,620
Permanent Modification | Home equity
Financing Receivable, Impaired [Line Items]
Number of contract modifications	1,692	770
Permanent Modification | Residential Mortgage
Financing Receivable, Impaired [Line Items]
Number of contract modifications	732	850