Investment Securities - Amortized Cost and Fair Value of Available-for-Sale Debt and Held-to-Maturity Securities (Details) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021
Available-for-Sale Debt and Other, Amortized Cost
Due in 1 year or less		$ 926
Due after 1 year through 5 years		13,519
Due after 5 years through 10 years		22,391
Due after 10 years		12,817
Other securities		518
Amortized Cost		50,171	$ 36,941
Available-for-Sale Debt and Other, Fair Value
Due in 1 year or less		923
Due after 1 year through 5 years		13,437
Due after 5 years through 10 years		21,811
Due after 10 years		12,143
Other securities		518
Fair Value	[1]	48,832	38,110
Held-to-Maturity, Amortized Cost
Due in 1 year or less		1
Due after 1 year through 5 years		3
Due after 5 years through 10 years		0
Due after 10 years		2
Other securities		0
Amortized Cost		6	8
Held-to-Maturity, Fair Value
Due in 1 year or less		1
Due after 1 year through 5 years		3
Due after 5 years through 10 years		0
Due after 10 years		2
Other securities		0
Fair Value		$ 6	$ 8

[1] Amortized cost of $50,171 and $36,941 at March 31, 2022 and December 31, 2021, respectively.