Loans and Allowance for Loan Losses - Loans in Consumer Portfolio Segment Based On LTV Ratios, Revolving and Nonrevolving (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Credit quality of consumer loans
Financing receivable	$ 86,535	$ 88,213
Consumer
Credit quality of consumer loans
2020	2,153
2019	7,629
2018	4,499
2017	7,232
2016	6,494
Prior	8,185
Revolving Loans	1,457
Financing receivable	$ 37,649	$ 42,468
2020 Percentage	6.00%
2019 Percentage	20.00%
2018 Percentage	12.00%
2017 Percentage	19.00%
2016 Percentage	17.00%
Prior Percentage	22.00%
Revolving Percentage	4.00%
Total	100.00%
Consumer | Residential mortgage and home equity
Credit quality of consumer loans
2020	$ 1,629
2019	5,372
2018	3,796
2017	7,178
2016	6,485
Prior	8,150
Revolving Loans	1,184
Financing receivable	$ 33,794
2020 Percentage	5.00%
2019 Percentage	16.00%
2018 Percentage	11.00%
2017 Percentage	21.00%
2016 Percentage	19.00%
Prior Percentage	24.00%
Revolving Percentage	4.00%
Total	100.00%
Consumer | Residential mortgage and home equity | 80% or below
Credit quality of consumer loans
2020	$ 1,613
2019	5,125
2018	3,593
2017	7,125
2016	6,476
Prior	8,077
Revolving Loans	1,067
Financing receivable	33,076
Consumer | Residential mortgage and home equity | 80% to 100%
Credit quality of consumer loans
2020	15
2019	247
2018	201
2017	52
2016	8
Prior	37
Revolving Loans	112
Financing receivable	672
Consumer | Residential mortgage and home equity | 100% or more
Credit quality of consumer loans
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	6
Revolving Loans	0
Financing receivable	6
Consumer | Residential mortgage and home equity | No LTV Available
Credit quality of consumer loans
2020	1
2019	0
2018	2
2017	1
2016	1
Prior	30
Revolving Loans	5
Financing receivable	40
Consumer Portfolio Segment Related to LTV Ratios
Credit quality of consumer loans
2020	1,629
2019	5,372
2018	3,796
2017	7,178
2016	6,485
Prior	8,150
Revolving Loans	1,184
Financing receivable	$ 33,794