Loans - Consumer, Excluding Credit Card Loan Portfolio, Residential Real Estate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Loans by origination year
Total retained loans	$ 1,299,590	$ 1,280,870	$ 1,089,598
Gross charge-offs by origination year
Total gross charge-offs	10,519	7,653	4,326
Consumer, excluding credit card
Loans by origination year
Total retained loans	376,334	397,275	300,753
Gross charge-offs by origination year
Total gross charge-offs	1,299	1,151	$ 812
Consumer, excluding credit card | Residential real estate
Loans by origination year
Term loans originated in 2024/2023	12,314	23,250
Term loans originated in 2023/2022	17,345	64,450
Term loans originated in 2022/2021	61,547	84,602
Term loans originated in 2021/2020	79,938	55,624
Term loans originated in 2020/2019	52,397	21,592
Term loans originated prior to 2020/2019	71,518	60,820
Revolving loans within revolving period	7,035	7,533
Revolving loans converted to term loans	7,419	8,538
Total retained loans	$ 309,513	$ 326,409
% 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 2024/2023	0.11%	0.15%
% of 30 plus days past due to total retained loans, Term loans originated in 2023/2022	0.37%	0.13%
% of 30 plus days past due to total retained loans, Term loans originated in 2022/2021	0.34%	0.13%
% of 30 plus days past due to total retained loans, Term loans originated in 2021/2020	0.22%	0.14%
% of 30 plus days past due to total retained loans, Term loans originated in 2020/2019	0.21%	0.29%
% of 30 plus days past due to total retained loans, Term loans originated prior to 2020/2019	1.72%	2.04%
% of 30 plus days past due to total retained loans, Revolving loans within the revolving period	0.87%	0.72%
% of 30 plus days past due to total retained loans, Revolving loans converted to term loans	4.46%	4.53%
% of 30 plus days past due to total retained loans	0.71%	0.63%
Gross charge-offs by origination year
Gross charge-offs originated in 2024/2023	$ 0	$ 0
Gross charge-offs originated in 2023/2022	0	0
Gross charge-offs originated in 2022/2021	1	0
Gross charge-offs originated in 2021/2020	1	0
Gross charge-offs originated in 2020/2019	0	4
Gross charge-offs originated prior to 2020/2019	176	167
Gross charge-offs originated within the revolving period	21	26
Gross charge-offs originated converted to term loans	7	7
Total gross charge-offs	$ 206	204
Consumer, excluding credit card | Residential real estate | Senior lien
Gross charge-offs by origination year
Percentage of total revolving loans that are senior lien loans	38.00%
Consumer, excluding credit card | Residential real estate | Current
Loans by origination year
Term loans originated in 2024/2023	$ 12,301	23,216
Term loans originated in 2023/2022	17,280	64,366
Term loans originated in 2022/2021	61,337	84,496
Term loans originated in 2021/2020	79,760	55,546
Term loans originated in 2020/2019	52,289	21,530
Term loans originated prior to 2020/2019	70,270	59,563
Revolving loans within revolving period	6,974	7,479
Revolving loans converted to term loans	7,088	8,151
Total retained loans	307,299	324,347
Consumer, excluding credit card | Residential real estate | 30–149 days past due
Loans by origination year
Term loans originated in 2024/2023	13	33
Term loans originated in 2023/2022	54	74
Term loans originated in 2022/2021	139	89
Term loans originated in 2021/2020	110	70
Term loans originated in 2020/2019	59	41
Term loans originated prior to 2020/2019	747	801
Revolving loans within revolving period	53	49
Revolving loans converted to term loans	204	223
Total retained loans	1,379	1,380
Consumer, excluding credit card | Residential real estate | 150 or more days past due
Loans by origination year
Term loans originated in 2024/2023	0	1
Term loans originated in 2023/2022	11	10
Term loans originated in 2022/2021	71	17
Term loans originated in 2021/2020	68	8
Term loans originated in 2020/2019	49	21
Term loans originated prior to 2020/2019	501	456
Revolving loans within revolving period	8	5
Revolving loans converted to term loans	127	164
Total retained loans	$ 835	$ 682