Securities - Summary of Amortized Cost of Available-for-Sale Securities by Contractual Maturity (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Available-for-Sale Debt Securities:
Due within one year, fair value		$ 77
Due from one to five years, fair value		594
Due from five to ten years, fair value		1,226
Due after ten years, fair value		3,883
Fair Value		5,780	$ 5,813
Mortgage-Related Securities
Available-for-Sale Debt Securities:
Due within one year		27
Due from one to five years		142
Due from five to ten years		271
Due after ten years		2,379
Amortized Cost		2,819
U.S. Government and GSE obligations
Available-for-Sale Debt Securities:
Due within one year		45
Due from one to five years		22
Due from five to ten years		423
Due after ten years		1,079
Amortized Cost		1,569
State, County, and Municipal
Available-for-Sale Debt Securities:
Due within one year
Due from one to five years
Due from five to ten years		19
Due after ten years		6
Amortized Cost		25
Other Debt Securities
Available-for-Sale Debt Securities:
Due within one year	[1]	5
Due from one to five years	[1]	408
Due from five to ten years	[1]	512
Due after ten years	[1]	496
Amortized Cost	[1]	$ 1,421

[1] Includes corporate bonds, capital trust notes, foreign notes, and asset-backed securities.