CONSOLIDATED STATEMENTS OF INCOME (unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023
Income Statement [Abstract]
Net sales		$ 689	$ 692	$ 2,068	$ 2,112
Cost of goods sold		495	496	1,475	1,544
Selling, general and administrative expense		162	179	468	497
Restructuring Costs		38	0	38	0
Operating profit (loss)		(6)	17	87	71
Interest expense		7	0	23	0
Other income (expense), net		(2)	38	8	53
Income (loss) before income taxes		(15)	55	72	124
Income taxes (benefit)		(4)	13	19	29
Net income (loss)		$ (11)	$ 42	$ 53	$ 95
Per share amounts:
Basic earnings (loss) (in dollars per share)	[1]	$ (0.13)	$ 0.49	$ 0.62	$ 1.10
Diluted earnings (loss) (in dollars per share)	[1]	$ (0.13)	$ 0.49	$ 0.60	$ 1.10
Average shares outstanding:
Basic (in shares)		86	86	86	86
Diluted (in shares)		86	86	88	86
Actual shares outstanding at period end (in shares)		86	86	86	86

[1] On October 2, 2023, Kellanova, the former parent company of WK Kellogg Co, distributed 85,631,304 shares of WK Kellogg Co common stock to Kellanova's shareowners in connection with its Spin-Off of WK Kellogg Co (the "Spin-Off"). See Note 1 "Accounting Policies" to the Unaudited Consolidated Financial Statements for more information. Basic and diluted earnings per share were retrospectively recast for the number of shares of WK Kellogg Co common stock outstanding immediately following the Spin-Off for the quarter and year-to-date period ended September 30, 2023.