Loans - Consumer, Excluding Credit Card Loan Portfolio, Auto and Other (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Loans by origination year
Total retained loans	$ 1,084,850	$ 1,018,397	$ 1,089,598
Gross charge-offs by origination year
Total gross charge-offs	1,451	976
Consumer, excluding credit card
Loans by origination year
Total retained loans	300,447	296,161	300,753
Gross charge-offs by origination year
Total gross charge-offs	235	$ 204
Consumer, excluding credit card | Auto and other
Loans by origination year
Term loans originated in 2023/2022	8,065		22,450
Term loans originated in 2022/2021	20,150		20,573
Term loans originated in 2021/2020	18,468		11,525
Term loans originated in 2020/2019	10,164		4,059
Term loans originated in 2019/2018	3,402		1,500
Term loans originated prior to 2019/2018	1,504		596
Revolving loans within the revolving period	2,441		2,356
Revolving loans converted to term loans	138		133
Total retained loans	$ 64,332		$ 63,192
% of 30+ days past due to total retained loans by origination year
% of 30 plus days past due to total retained loans, Term loans originated in 2023/2022	0.88%		1.17%
% of 30 plus days past due to total retained loans, Term loans originated in 2022/2021	1.05%		1.15%
% of 30 plus days past due to total retained loans, Term loans originated in 2021/2020	1.12%		0.83%
% of 30 plus days past due to total retained loans, Term loans originated in 2020/2019	0.74%		1.68%
% of 30 plus days past due to total retained loans, Term loans originated in 2019/2018	1.53%		2.20%
% of 30 plus days past due to total retained loans, Term loans originated prior to 2019/2018	2.39%		3.02%
% of 30 plus days past due to total retained loans, Revolving loans within the revolving period	0.57%		0.59%
% of 30 plus days past due to total retained loans, Revolving loans converted to term loans	19.57%		11.28%
% of 30 plus days past due to total retained loans	1.08%		1.18%
Gross charge-offs by origination year
Gross charge-offs originated in 2023	$ 27
Gross charge-offs originated in 2022	112
Gross charge-offs originated in 2021	41
Gross charge-offs originated in 2020	14
Gross charge-offs originated in 2019	9
Gross charge-offs originated prior to 2019	14
Gross charge-offs originated within the revolving period	0
Gross charge-offs originated converted to term loans	0
Total gross charge-offs	217
Current | Consumer, excluding credit card | Auto and other
Loans by origination year
Term loans originated in 2023/2022	7,994		$ 22,187
Term loans originated in 2022/2021	19,938		20,212
Term loans originated in 2021/2020	18,215		11,401
Term loans originated in 2020/2019	10,071		3,991
Term loans originated in 2019/2018	3,350		1,467
Term loans originated prior to 2019/2018	1,468		578
Revolving loans within the revolving period	2,427		2,342
Revolving loans converted to term loans	111		118
Total retained loans	63,574		62,296
30 or more days past due | Consumer, excluding credit card | Auto and other | Paycheck Protection Program (PPP)
Loans by origination year
Total retained loans	65		153
30–119 days past due | Consumer, excluding credit card | Auto and other
Loans by origination year
Term loans originated in 2023/2022	71		263
Term loans originated in 2022/2021	212		308
Term loans originated in 2021/2020	217		100
Term loans originated in 2020/2019	76		68
Term loans originated in 2019/2018	52		33
Term loans originated prior to 2019/2018	35		17
Revolving loans within the revolving period	12		12
Revolving loans converted to term loans	19		10
Total retained loans	694		811
120 or more days past due | Consumer, excluding credit card | Auto and other
Loans by origination year
Term loans originated in 2023/2022	0		0
Term loans originated in 2022/2021	0		53
Term loans originated in 2021/2020	36		24
Term loans originated in 2020/2019	17		0
Term loans originated in 2019/2018	0		0
Term loans originated prior to 2019/2018	1		1
Revolving loans within the revolving period	2		2
Revolving loans converted to term loans	8		5
Total retained loans	$ 64		$ 85