Loans - Consumer, Excluding Credit Card Loan Portfolio, Auto and Other (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	$ 1,089,598	$ 1,010,206	$ 960,506
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	300,753	295,556	$ 302,127
Consumer, excluding credit card | Auto and other
Loans and Leases Receivable Disclosure [Line Items]
Term loans originated in 2022/2021	22,450	35,515
Term loans originated in 2021/2020	20,573	19,079
Term loans originated in 2020/2019	11,525	7,531
Term loans originated in 2019/2018	4,059	3,724
Term loans originated in 2018/2017	1,500	1,832
Term loans originated prior to 2018/2017	596	688
Revolving loans within revolving period	2,356	2,259
Revolving loans converted to term loans	133	133
Total retained loans	$ 63,192	$ 70,761
% of 30 plus days past due to total retained loans, Term loans originated in 2022/2021	1.17%	0.54%
% of 30 plus days past due to total retained loans, Term loans originated in 2021/2020	1.15%	0.47%
% of 30 plus days past due to total retained loans, Term loans originated in 2020/2019	0.83%	1.17%
% of 30 plus days past due to total retained loans, Term loans originated in 2019/2018	1.68%	1.42%
% of 30 plus days past due to total retained loans, Term loans originated in 2018/2017	2.20%	1.75%
% of 30 plus days past due to total retained loans, Term loans originated prior to 2018/2017	3.02%	3.20%
% of 30 plus days past due to total retained loans, Revolving loans within the revolving period	0.59%	0.75%
% of 30 plus days past due to total retained loans, Revolving loans converted to term loans	11.28%	9.77%
% of 30 plus days past due to total retained loans	1.18%	0.71%
Consumer, excluding credit card | Auto and other | Paycheck Protection Program (PPP)
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	$ 350	$ 5,400
Consumer, excluding credit card | Auto and other | Current
Loans and Leases Receivable Disclosure [Line Items]
Term loans originated in 2022/2021	22,187	35,323
Term loans originated in 2021/2020	20,212	18,324
Term loans originated in 2020/2019	11,401	7,443
Term loans originated in 2019/2018	3,991	3,671
Term loans originated in 2018/2017	1,467	1,800
Term loans originated prior to 2018/2017	578	666
Revolving loans within revolving period	2,342	2,242
Revolving loans converted to term loans	118	120
Total retained loans	62,296	69,589
Consumer, excluding credit card | Auto and other | Current | Paycheck Protection Program (PPP)
Loans and Leases Receivable Disclosure [Line Items]
Term loans originated in 2022/2021	252	4,400
Term loans originated in 2021/2020	98	1,000
Consumer, excluding credit card | Auto and other | 30–119 days past due
Loans and Leases Receivable Disclosure [Line Items]
Term loans originated in 2022/2021	263	192
Term loans originated in 2021/2020	308	720
Term loans originated in 2020/2019	100	88
Term loans originated in 2019/2018	68	53
Term loans originated in 2018/2017	33	31
Term loans originated prior to 2018/2017	17	21
Revolving loans within revolving period	12	12
Revolving loans converted to term loans	10	6
Total retained loans	811	1,123
Consumer, excluding credit card | Auto and other | 120 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Term loans originated in 2022/2021	0	0
Term loans originated in 2021/2020	53	35
Term loans originated in 2020/2019	24	0
Term loans originated in 2019/2018	0	0
Term loans originated in 2018/2017	0	1
Term loans originated prior to 2018/2017	1	1
Revolving loans within revolving period	2	5
Revolving loans converted to term loans	5	7
Total retained loans	85	49
Consumer, excluding credit card | Auto and other | 30 or more days past due | Paycheck Protection Program (PPP)
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	$ 153	$ 667