Asset Quality (Consumer Real Estate Secured Asset Quality Indicators) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
% of Loans	100.00%	100.00%
Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	$ 15,502	$ 16,076
Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	10,858	11,378
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	15,696	14,883
Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	$ 42,056	$ 42,337
Total home equity and residential real estate loans [Member] | New Jersey [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	17.00%	17.00%
Total home equity and residential real estate loans [Member] | Pennsylvania [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	17.00%	13.00%
Total home equity and residential real estate loans [Member] | Illinois [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	13.00%	13.00%
Total home equity and residential real estate loans [Member] | Ohio [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	9.00%	9.00%
Total home equity and residential real estate loans [Member] | Maryland [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	7.00%	8.00%
Total home equity and residential real estate loans [Member] | Florida [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	5.00%	6.00%
Total home equity and residential real estate loans [Member] | North Carolina [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	4.00%	5.00%
Total home equity and residential real estate loans [Member] | Michigan [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	4.00%	4.00%
Total home equity and residential real estate loans [Member] | All Other States Maximum [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	4.00%	4.00%
Total home equity and residential real estate loans [Member] | All Other States [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	24.00%	25.00%
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	$ 184	$ 108
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	385	385
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	161	126
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	730	619
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	25	21
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	52	64
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	24	23
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	101	108
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	1	1
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	4	5
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	2	1
LTV greater than or equal to 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	7	7
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	333	300
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	781	842
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	302	253
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	1,416	1,395
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	47	46
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	97	143
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	31	45
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	175	234
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	2	2
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	5	9
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	3	5
LTV greater than or equal to 100% to less than 125% and updated FICO scores [Member] | FICO Score- Missing [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	10	16
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	332	331
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	863	890
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	337	324
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	1,532	1,545
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	44	55
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	97	134
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	30	55
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	171	244
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	2	2
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	5	9
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Missing [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	2	4
LTV greater than or equal to 90% to less than 100% and updated FICO scores [Member] | FICO Score- Missing [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	9	15
LTV less than 90% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	13,340	13,954
LTV less than 90% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	7,735	8,066
LTV less than 90% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	14,145	13,445
LTV less than 90% and updated FICO scores [Member] | FICO Score- Greater than 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	35,220	35,465
LTV less than 90% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	1,157	1,214
LTV less than 90% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	778	774
LTV less than 90% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	562	507
LTV less than 90% and updated FICO scores [Member] | FICO Score- Less than or equal to 660 [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	2,497	2,495
LTV less than 90% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 1st Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	35	42
LTV less than 90% and updated FICO scores [Member] | FICO Score- Missing [Member] | Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	56	57
LTV less than 90% and updated FICO scores [Member] | FICO Score- Missing [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	97	95
LTV less than 90% and updated FICO scores [Member] | FICO Score- Missing [Member] | Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	$ 188	$ 194