Investment Securities (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Summary of AFS Securities

The following tables summarize the Company’s AFS securities:

December 31, 2021 (Dollars in millions)	Amortized Cost		Gross Unrealized				Fair Value
			Gains		Losses
AFS securities:
U.S. Treasury	$	9,892	$	9	$	106	$	9,795
GSE	1,667		33		2		1,698
Agency MBS - residential	135,886		656		2,500		134,042
Agency MBS - commercial	2,928		18		64		2,882
States and political subdivisions	382		39		1		420
Non-agency MBS	4,305		—		47		4,258
Other	28		—		—		28
Total AFS securities	$	155,088	$	755	$	2,720	$	153,123
HTM securities:
Agency MBS - residential	$	1,494	$	1	$	—	$	1,495
December 31, 2020 (Dollars in millions)	Amortized Cost		Gross Unrealized				Fair Value
			Gains		Losses
AFS securities:
U.S. Treasury	$	1,721	$	25	$	—	$	1,746
GSE	1,840		77		—		1,917
Agency MBS - residential	111,589		1,975		23		113,541
Agency MBS - commercial	2,987		72		2		3,057
States and political subdivisions	447		47		1		493
Other	34		—		—		34
Total AFS securities	$	118,618	$	2,196	$	26	$	120,788

Schedule of Amortized Cost and Estimated Fair Value by Contractual Maturity

The amortized cost and estimated fair value of the securities portfolio by contractual maturity are shown in the following table. The expected life of MBS may be shorter than the contractual maturities because borrowers may have the right to prepay their obligations with or without penalties.

	Amortized Cost										Fair Value
December 31, 2021 (Dollars in millions)	Due in one year or less		Due after one year through five years		Due after five years through ten years		Due after ten years		Total		Due in one year or less		Due after one year through five years		Due after five years through ten years		Due after ten years		Total
AFS securities:
U.S. Treasury	$	290	$	8,623	$	979	$	—	$	9,892	$	290	$	8,532	$	973	$	—	$	9,795
GSE	426		1,062		—		179		1,667		432		1,086		—		180		1,698
Agency MBS - residential	—		1		592		135,293		135,886		—		1		611		133,430		134,042
Agency MBS - commercial	—		8		15		2,905		2,928		—		9		15		2,858		2,882
States and political subdivisions	31		77		117		157		382		31		80		135		174		420
Non-agency MBS	—		—		—		4,305		4,305		—		—		—		4,258		4,258
Other	1		6		—		21		28		1		6		—		21		28
Total AFS securities	$	748	$	9,777	$	1,703	$	142,860	$	155,088	$	754	$	9,714	$	1,734	$	140,921	$	153,123
HTM securities:
Agency MBS - residential	$	—	$	—	$	—	$	1,494	$	1,494	$	—	$	—	$	—	$	1,495	$	1,495

Schedule of Fair Values and Gross Unrealized Losses

The following tables present the fair values and gross unrealized losses of investments based on the length of time that individual securities have been in a continuous unrealized loss position:

	Less than 12 months				12 months or more				Total
December 31, 2021 (Dollars in millions)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
AFS securities:
U.S. Treasury	$	8,412	$	88	$	582	$	18	$	8,994	$	106
GSE	104		2		—		—		104		2
Agency MBS - residential	101,262		2,377		2,638		123		103,900		2,500
Agency MBS - commercial	1,749		50		413		14		2,162		64
States and political subdivisions	—		—		22		1		22		1
Non-agency MBS	4,258		47		—		—		4,258		47
Other	6		—		—		—		6		—
Total	$	115,791	$	2,564	$	3,655	$	156	$	119,446	$	2,720
	Less than 12 months				12 months or more				Total
December 31, 2020 (Dollars in millions)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
AFS securities:
U.S. Treasury	$	17	$	—	$	—	$	—	$	17	$	—
Agency MBS - residential	4,028		21		203		2		4,231		23
Agency MBS - commercial	463		2		4		—		467		2
States and political subdivisions	20		—		32		1		52		1
Other	6		—		—		—		6		—
Total	$	4,534	$	23	$	239	$	3	$	4,773	$	26

Schedule of Realized Gain (Loss)

The following table presents gross securities gains and losses recognized in earnings:

(Dollars in millions)	Year Ended December 31,
	2021		2020		2019
Gross realized gains	$	—	$	404	$	47
Gross realized losses	—		(2)		(163)
Securities gains (losses), net	$	—	$	402	$	(116)