Investment Securities - Maturities of Securities Available for Sale and Held to Maturity (Details) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
Available for sale securities, fair value
Within 1 year		$ 11,890
After 1 year through 5 years		37,571
After 5 years through 10 years		14,579
After 10 years		46,232
Total	[1]	110,272	$ 147,871
Available for sale securities, amortized cost
Amortized Cost		122,129
Held to maturity securities, fair value
Within 1 year		724
After 1 year through 5 years		6,780
After 5 years through 10 years		36,652
After 10 years		98,847
Total		143,003	158,936
Held to maturity securities, amortized cost
Within 1 year		749
After 1 year through 5 years		7,343
After 5 years through 10 years		41,217
After 10 years		113,143
Amortized Cost		162,452
Portfolio layer method fair value hedge basis adjustments, excluded from amortized cost of available for sale securities		57
Within 1 year		12,128
After 1 year through 5 years		40,565
After 5 years through 10 years		16,667
After 10 years		52,769
U.S. agency mortgage-backed securities
Available for sale securities, fair value
Within 1 year		494
After 1 year through 5 years		12,620
After 5 years through 10 years		11,503
After 10 years		40,244
Total		64,861	77,688
Held to maturity securities, fair value
Within 1 year		724
After 1 year through 5 years		6,780
After 5 years through 10 years		36,652
After 10 years		98,847
Total		143,003	158,936
U.S. Treasury securities
Available for sale securities, fair value
Within 1 year		8,649
After 1 year through 5 years		13,139
After 5 years through 10 years		0
After 10 years		0
Total		21,788	40,002
Asset-backed securities
Available for sale securities, fair value
Within 1 year		0
After 1 year through 5 years		2,755
After 5 years through 10 years		1,209
After 10 years		5,660
Total		9,624	13,023
Corporate debt securities
Available for sale securities, fair value
Within 1 year		2,160
After 1 year through 5 years		8,514
After 5 years through 10 years		1,480
After 10 years		0
Total		12,154	12,555
Certificates of deposit
Available for sale securities, fair value
Within 1 year		99
After 1 year through 5 years		0
After 5 years through 10 years		0
After 10 years		0
Total		99	2,231
Foreign government agency securities
Available for sale securities, fair value
Within 1 year		488
After 1 year through 5 years		497
After 5 years through 10 years		0
After 10 years		0
Total		985	969
U.S. state and municipal securities
Available for sale securities, fair value
Within 1 year		0
After 1 year through 5 years		46
After 5 years through 10 years		387
After 10 years		122
Total		555	638
Non-agency commercial mortgage-backed securities
Available for sale securities, fair value
Within 1 year		0
After 1 year through 5 years		0
After 5 years through 10 years		0
After 10 years		188
Total		188	450
Other
Available for sale securities, fair value
Within 1 year		0
After 1 year through 5 years		0
After 5 years through 10 years		0
After 10 years		18
Total		$ 18	$ 315

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.