Asset Quality (Consumer Real Estate Secured Asset Quality Indicators) (Details) - USD ($) $ in Millions	Sep. 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	$ 15,119	$ 16,076
Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	10,669	11,378
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	16,166	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	$ 41,954	$ 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	12.00%	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	5.00%	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	$ 163	$ 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	348	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	134	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	645	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	27	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	47	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	15	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	89	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	1	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	6	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	280	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	720	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	269	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	1,269	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	38	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	89	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	30	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	157	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	1	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	9	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	299	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	814	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	315	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	1,428	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	41	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	93	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	24	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	158	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	4	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	11	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	13,075	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	7,721	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	14,724	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	35,520	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	775	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	555	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	2,487	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	48	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	92	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	$ 175	$ 194