Asset Quality (Consumer Real Estate Secured Asset Quality Indicators) (Details) - USD ($) $ in Millions	Mar. 31, 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	$ 15,757	$ 16,076
Home Equity [Member] | 2nd Liens [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	11,057	11,378
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - excluding purchased impaired and government insured or guaranteed loans	15,252	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	$ 42,066	$ 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	16.00%	17.00%
Total home equity and residential real estate loans [Member] | Pennsylvania [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	13.00%	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	10.00%	9.00%
Total home equity and residential real estate loans [Member] | Maryland [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	8.00%	8.00%
Total home equity and residential real estate loans [Member] | Florida [Member] | High Risk [Member]
Financing Receivable, Recorded Investment [Line Items]
% of Loans	6.00%	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	26.00%	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	$ 99	$ 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	359	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	123	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	581	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	16	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	58	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	98	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	277	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	794	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	249	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	1,320	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	45	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	133	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	49	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	227	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	8	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	5	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	14	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	333	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	853	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	300	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	1,486	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	51	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	132	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	51	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	234	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	8	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	3	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	13	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	13,678	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	7,877	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	13,795	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	35,350	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	1,212	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	2,542	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	42	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	$ 195	$ 194