Investment securities (Tables)

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Estimated Fair Value of Investment Securities

The amortized cost and estimated fair value of investment securities were as follows:

(Dollars in millions)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
June 30, 2024
Investment securities available for sale:
U.S. Treasury and federal agencies	$	7,819	$	2	$	85	$	7,736
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	2,101		4		16		2,089
Residential	4,108		6		148		3,966
Other debt securities	103		—		2		101
	14,131		12		251		13,892
Investment securities held to maturity:
U.S. Treasury and federal agencies	1,010		—		30		980
Obligations of states and political subdivisions	2,433		—		127		2,306
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	2,037		—		157		1,880
Residential	9,272		—		972		8,300
Privately issued	40		7		5		42
Other debt securities	1		—		—		1
	14,793		7		1,291		13,509
Total debt securities	$	28,924	$	19	$	1,542	$	27,401
Equity and other securities:
Readily marketable equity — at fair value	$	272	$	11	$	3	$	280
Other — at cost	929		—		—		929
Total equity and other securities	$	1,201	$	11	$	3	$	1,209
December 31, 2023
Investment securities available for sale:
U.S. Treasury and federal agencies	$	7,818	$	—	$	113	$	7,705
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	425		—		9		416
Residential	2,272		—		118		2,154
Other debt securities	176		—		11		165
	10,691		—		251		10,440
Investment securities held to maturity:
U.S. Treasury and federal agencies	1,005		—		31		974
Obligations of states and political subdivisions	2,501		—		67		2,434
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	2,033		—		130		1,903
Residential	9,747		4		802		8,949
Privately issued	42		9		5		46
Other debt securities	2		—		—		2
	15,330		13		1,035		14,308
Total debt securities	$	26,021	$	13	$	1,286	$	24,748
Equity and other securities:
Readily marketable equity — at fair value	$	266	$	5	$	3	$	268
Other — at cost	859		—		—		859
Total equity and other securities	$	1,125	$	5	$	3	$	1,127

Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity

At June 30, 2024, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows:

(Dollars in millions)	Amortized Cost		Estimated Fair Value
Debt securities available for sale:
Due in one year or less	$	3,133	$	3,093
Due after one year through five years	4,789		4,744
Due after five years through ten years	—		—
Due after ten years	—		—
	7,922		7,837
Mortgage-backed securities	6,209		6,055
	$	14,131	$	13,892
Debt securities held to maturity:
Due in one year or less	$	588	$	579
Due after one year through five years	653		628
Due after five years through ten years	1,392		1,332
Due after ten years	811		748
	3,444		3,287
Mortgage-backed securities	11,349		10,222
	$	14,793	$	13,509

Investment Securities in Continuous Unrealized Loss Position

A summary of investment securities that as of June 30, 2024 and December 31, 2023 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows:

	Less Than 12 Months				12 Months or More
(Dollars in millions)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
June 30, 2024
Investment securities available for sale:
U.S. Treasury and federal agencies	$	2,586	$	15	$	4,400	$	70
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	1,061		10		317		6
Residential	1,129		11		1,874		137
Other debt securities	10		—		64		2
	4,786		36		6,655		215
Investment securities held to maturity:
U.S. Treasury and federal agencies	—		—		980		30
Obligations of states and political subdivisions	45		1		2,214		126
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	—		—		1,880		157
Residential	790		13		7,510		959
Privately issued	—		—		31		5
	835		14		12,615		1,277
Total	$	5,621	$	50	$	19,270	$	1,492
December 31, 2023
Investment securities available for sale:
U.S. Treasury and federal agencies	$	229	$	1	$	7,474	$	112
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	74		1		330		8
Residential	151		2		1,959		116
Other debt securities	6		—		154		11
	460		4		9,917		247
Investment securities held to maturity:
U.S. Treasury and federal agencies	50		—		924		31
Obligations of states and political subdivisions	218		3		2,172		64
Mortgage-backed securities:
Government issued or guaranteed:
Commercial	328		9		1,575		121
Residential	955		11		7,139		791
Privately issued	—		—		34		5
	1,551		23		11,844		1,012
Total	$	2,011	$	27	$	21,761	$	1,259