Investment Securities - Amortized Cost and Fair Value of Available-for-Sale Debt and Held-to-Maturity Securities (Details) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023
Available-for-Sale Debt and Other, Amortized Cost
Due in 1 year or less		$ 1,323
Due after 1 year through 5 years		16,987
Due after 5 years through 10 years		15,990
Due after 10 years		8,300
Other securities		800
Amortized Cost		43,400	$ 55,789
Available-for-Sale Debt and Other, Fair Value
Due in 1 year or less		1,301
Due after 1 year through 5 years		15,961
Due after 5 years through 10 years		13,635
Due after 10 years		7,094
Other securities		800
Fair Value	[1]	38,791	50,419
Held-to-Maturity, Amortized Cost
Due in 1 year or less		38
Due after 1 year through 5 years		2,644
Due after 5 years through 10 years		8,210
Due after 10 years		628
Other securities		0
Amortized Cost	[2]	11,520	2
Held-to-Maturity, Fair Value
Due in 1 year or less		38
Due after 1 year through 5 years		2,612
Due after 5 years through 10 years		8,063
Due after 10 years		628
Other securities		0
Fair Value		$ 11,341	$ 2

[1] Amortized cost of $43,400 and $55,789 at March 31, 2024 and December 31, 2023, respectively.

[2] Fair value of $11,341 and $2 at March 31, 2024 and December 31, 2023, respectively.