Consolidated Statements of Income - USD ($) shares in Thousands, $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
INTEREST INCOME
Loans		$ 1,538	$ 1,476
Loans held for sale		14	13
Securities available for sale		232	194
Held-to-maturity securities		75	74
Trading account assets		14	12
Short-term investments		142	42
Other investments		17	13
Total interest income		2,032	1,824
INTEREST EXPENSE
Deposits		782	350
Federal funds purchased and securities sold under repurchase agreements		1	22
Bank notes and other short-term borrowings		46	78
Long-term debt		328	275
Total interest expense		1,157	725
NET INTEREST INCOME		875	1,099
Provision for credit losses		101	139
Net interest income after provision for credit losses		774	960
NONINTEREST INCOME
Trust and investment services income		136	128
Investment banking and debt placement fees		170	145
Cards and payments income		77	81
Service charges on deposit accounts		63	67
Corporate services income		69	76
Commercial mortgage servicing fees		56	46
Corporate-owned life insurance income		32	29
Consumer mortgage income		14	11
Operating lease income and other leasing gains		24	25
Other income		6	0
Total noninterest income		647	608
NONINTEREST EXPENSE
Personnel		674	701
Net occupancy		67	70
Computer processing		102	92
Business services and professional fees		41	45
Equipment		20	22
Operating lease expense		17	20
Marketing		19	21
Other expense		203	205
Total noninterest expense		1,143	1,176
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES		278	392
Income taxes		59	81
INCOME (LOSS) FROM CONTINUING OPERATIONS		219	311
Income (loss) from discontinued operations		0	1
NET INCOME (LOSS)		219	312
Less: Net income (loss) attributable to noncontrolling interests		0	0
NET INCOME (LOSS) ATTRIBUTABLE TO KEY		219	312
Income (loss) from continuing operations attributable to Key common shareholders		183	275
Net income (loss) attributable to Key common shareholders		$ 183	$ 276
Per Common Share:
Income (loss) from continuing operations attributable to Key common shareholders (in usd per share)		$ 0.20	$ 0.30
Income (loss) from discontinued operations, net of taxes (in usd per share)		0	0
Net income (loss) attributable to Key common shareholders (in usd per share)	[1]	0.20	0.30
Per Common Share — assuming dilution:
Income (loss) from continuing operations attributable to Key common shareholders (in usd per share)		0.20	0.30
Income (loss) from discontinued operations, net of taxes (in usd per share)		0	0
Net income (loss) attributable to Key common shareholders (in usd per share)	[1]	$ 0.20	$ 0.30
Weighted-average Common Shares outstanding (in shares)		929,692	926,490
Effect of Common Share options and other stock awards (in shares)		7,319	7,314
Weighted-average Common Shares and potential Common Shares outstanding (in shares)	[2]	937,011	933,804

[1] EPS may not foot due to rounding.

[2] Assumes conversion of Common Share options and other stock awards and/or convertible preferred stock, as applicable.