Asset Quality (Consumer Real Estate Secured Asset Quality Indicators) (Details) - USD ($) $ in Millions	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 226,245	[1]	$ 220,458	[1]	$ 210,833
Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	26,123		28,364
Home Equity | Government Insured or Guaranteed Loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans
Home Equity | Purchased Impaired Loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans	679		881
Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	18,657		17,212
Residential Real Estate | Government Insured or Guaranteed Loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans	685		806
Residential Real Estate | Purchased Impaired Loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,338		1,515
FICO Score- Greater than 660 | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	22,996		24,876
FICO Score- Greater than 660 | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,956		14,148
FICO Score- Less than or equal to 660 | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,210		2,451
FICO Score- Less than or equal to 660 | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	585		630
No FICO score available | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	238		156
No FICO score available | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	93		113
LTV greater than or equal to 125% | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	461		583
LTV greater than or equal to 125% | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	116		150
LTV greater than or equal to 100% to less than 125% | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,020		1,342
LTV greater than or equal to 100% to less than 125% | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	255		303
LTV greater than or equal to 90% to less than 100% | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,174		1,421
LTV greater than or equal to 90% to less than 100% | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	335		382
LTV less than 90% | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	22,644		24,105
LTV less than 90% | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,922		14,033
No LTV ratio available | Home Equity
Financing Receivable, Recorded Investment [Line Items]
Total Loans	145		32
No LTV ratio available | Residential Real Estate
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 6		$ 23

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $.9 billion, Loans of $.8 billion, and Other assets of $.2 billion at December 31, 2018 and Loans held for sale of $1.7 billion, Loans of $.9 billion, and Other assets of $.3 billion at December 31, 2017.