Securities - Maturity Distribution and Yield of Investment Securities Portfolio (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Securities available-for-sale, Amount:
Within 1 year	$ 10,978
1-5 years	33,636
5-10 years	15,353
After 10 years	2,750
Available-for-sale, amount	$ 91,278	$ 101,839
Securities available-for-sale (Yield):
Within 1 year	1.48%
1-5 years	1.06%
5-10 years	1.22%
After 10 years	2.78%
Total	1.57%
Securities held-to-maturity, Amount:
Within 1 year	$ 1,784
1-5 years	11,317
5-10 years	3,914
After 10 years	268
Available-for-sale, amount	$ 59,566	56,866
Securities held-to-maturity (Yield):
Within 1 year	1.73%
1-5 years	1.19%
5-10 years	1.32%
After 10 years	1.98%
Total	2.00%
Total securities	$ 12,762
Total securities (percent)	1.52%
Total securities	$ 44,953
Total securities (percent)	1.09%
Total securities	$ 19,267
Total securities (percent)	1.24%
Total securities	$ 3,018
Total securities (percent)	2.72%
Total securities	$ 150,844
Total securities (percent)	1.73%
U.S. Treasury
Securities available-for-sale, Amount:
Within 1 year	$ 3,978
1-5 years	15,195
5-10 years	9,052
After 10 years	2,242
Available-for-sale, amount	$ 30,467	29,409
Securities available-for-sale (Yield):
Within 1 year	1.84%
1-5 years	1.05%
5-10 years	1.15%
After 10 years	2.92%
Total	1.32%
Securities held-to-maturity, Amount:
Within 1 year	$ 1,590
1-5 years	7,800
5-10 years	1,957
After 10 years	0
Available-for-sale, amount	$ 11,347	11,617
Securities held-to-maturity (Yield):
Within 1 year	1.91%
1-5 years	1.26%
5-10 years	1.16%
After 10 years	0.00%
Total	1.33%
Sovereign debt/sovereign guaranteed
Securities available-for-sale, Amount:
Within 1 year	$ 3,750
1-5 years	6,242
5-10 years	1,020
After 10 years	80
Available-for-sale, amount	$ 11,092
Securities available-for-sale (Yield):
Within 1 year	1.27%
1-5 years	0.79%
5-10 years	0.38%
After 10 years	1.78%
Total	0.91%
Securities held-to-maturity, Amount:
Within 1 year	$ 193
1-5 years	1,190
5-10 years	89
After 10 years	0
Available-for-sale, amount	$ 1,472
Securities held-to-maturity (Yield):
Within 1 year	0.25%
1-5 years	0.87%
5-10 years	0.53%
After 10 years	0.00%
Total	0.77%
Supranational
Securities available-for-sale, Amount:
Within 1 year	$ 905
1-5 years	4,964
5-10 years	1,662
After 10 years	17
Available-for-sale, amount	$ 7,548	7,573
Securities available-for-sale (Yield):
Within 1 year	1.05%
1-5 years	1.15%
5-10 years	1.50%
After 10 years	(0.09%)
Total	1.21%
Securities held-to-maturity, Amount:
Within 1 year	$ 0
1-5 years	325
5-10 years	0
After 10 years	0
Available-for-sale, amount	$ 325	54
Securities held-to-maturity (Yield):
Within 1 year	0.00%
1-5 years	0.70%
5-10 years	0.00%
After 10 years	0.00%
Total	0.70%
Foreign covered bonds
Securities available-for-sale, Amount:
Within 1 year	$ 1,503
1-5 years	3,735
5-10 years	590
After 10 years	0
Available-for-sale, amount	$ 5,828	6,238
Securities available-for-sale (Yield):
Within 1 year	1.27%
1-5 years	1.09%
5-10 years	0.08%
After 10 years	0.00%
Total	1.03%
Foreign government agencies
Securities available-for-sale, Amount:
Within 1 year	$ 583
1-5 years	1,918
5-10 years	35
After 10 years	0
Available-for-sale, amount	$ 2,536
Securities available-for-sale (Yield):
Within 1 year	0.91%
1-5 years	0.99%
5-10 years	0.16%
After 10 years	0.00%
Total	0.96%
Securities held-to-maturity, Amount:
Within 1 year	$ 0
1-5 years	64
5-10 years	0
After 10 years	0
Available-for-sale, amount	$ 64
Securities held-to-maturity (Yield):
Within 1 year	0.00%
1-5 years	0.79%
5-10 years	0.00%
After 10 years	0.00%
Total	0.79%
State and political subdivisions
Securities available-for-sale, Amount:
Within 1 year	$ 145
1-5 years	646
5-10 years	1,030
After 10 years	202
Available-for-sale, amount	$ 2,023	2,514
Securities available-for-sale (Yield):
Within 1 year	3.47%
1-5 years	1.63%
5-10 years	1.61%
After 10 years	2.33%
Total	1.81%
Securities held-to-maturity, Amount:
Within 1 year	$ 1
1-5 years	1
5-10 years	4
After 10 years	8
Available-for-sale, amount	$ 14	14
Securities held-to-maturity (Yield):
Within 1 year	5.51%
1-5 years	5.76%
5-10 years	4.65%
After 10 years	4.80%
Total	4.84%
U.S. government agencies
Securities available-for-sale, Amount:
Within 1 year	$ 0
1-5 years	579
5-10 years	1,160
After 10 years	186
Available-for-sale, amount	$ 1,925	2,536
Securities available-for-sale (Yield):
Within 1 year	0.00%
1-5 years	2.19%
5-10 years	2.22%
After 10 years	2.52%
Total	2.24%
Securities held-to-maturity, Amount:
Within 1 year	$ 0
1-5 years	1,937
5-10 years	1,864
After 10 years	260
Available-for-sale, amount	$ 4,061	2,998
Securities held-to-maturity (Yield):
Within 1 year	0.00%
1-5 years	1.20%
5-10 years	1.52%
After 10 years	1.90%
Total	1.39%
Corporate bonds
Securities available-for-sale, Amount:
Within 1 year	$ 114
1-5 years	357
5-10 years	804
After 10 years	22
Available-for-sale, amount	$ 1,297
Securities available-for-sale (Yield):
Within 1 year	2.30%
1-5 years	2.59%
5-10 years	1.61%
After 10 years	2.01%
Total	1.92%
Other debt securities
Securities available-for-sale, Amount:
Within 1 year	$ 0
1-5 years	0
5-10 years	0
After 10 years	1
Available-for-sale, amount	$ 1	1
Securities available-for-sale (Yield):
Within 1 year	0.00%
1-5 years	0.00%
5-10 years	0.00%
After 10 years	3.70%
Total	3.70%
Agency residential mortgage-backed securities (“RMBS”)
Securities available-for-sale, Amount:
Available-for-sale, amount	$ 8,303	14,530
Securities held-to-maturity, Amount:
Available-for-sale, amount	$ 36,947	36,167
Agency residential mortgage-backed securities (“RMBS”) | Mortgage-backed securities
Securities available-for-sale (Yield):
Total	2.14%
Securities held-to-maturity (Yield):
Total	2.29%
Non-agency RMBS
Securities available-for-sale, Amount:
Available-for-sale, amount	$ 2,311	2,748
Securities available-for-sale (Yield):
Total	3.20%
Securities held-to-maturity, Amount:
Available-for-sale, amount	$ 34	43
Securities held-to-maturity (Yield):
Total	1.80%
Agency commercial mortgage-backed securities (“MBS”)
Securities available-for-sale, Amount:
Available-for-sale, amount	$ 8,179	8,405
Securities available-for-sale (Yield):
Total	2.31%
Securities held-to-maturity, Amount:
Available-for-sale, amount	$ 4,319	4,068
Securities held-to-maturity (Yield):
Total	2.28%
Non-agency commercial MBS
Securities available-for-sale, Amount:
Available-for-sale, amount	$ 3,003	3,125
Securities available-for-sale (Yield):
Total	2.45%
Collateralized loan obligations (“CLOs”)
Securities available-for-sale, Amount:
Available-for-sale, amount	$ 5,097	4,439
Securities available-for-sale (Yield):
Total	2.15%
Securities held-to-maturity, Amount:
Available-for-sale, amount	$ 983	983
Securities held-to-maturity (Yield):
Total	2.10%
Other asset-backed securities (“ABS”)
Securities available-for-sale, Amount:
Available-for-sale, amount	$ 1,668	$ 2,190
Securities available-for-sale (Yield):
Total	1.72%