Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Total Alight, Inc. Equity	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Noncontrolling Interest
Beginning balance at Dec. 31, 2022	$ 5,089	$ 4,439	$ 0	$ (12)	$ 4,514	$ (158)	$ 95	$ 650
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(362)	(345)				(345)		(17)
Other comprehensive income (loss), net	(33)	(24)					(24)	(9)
Common stock issued under ESPP	10	10			10
Conversion of non-controlling interest	(66)	278			278			(344)
Share-based compensation expense	160	160			160
Shares withheld in lieu of taxes	(16)	(16)			(16)
Share repurchases	(40)	(40)		(40)
Ending balance at Dec. 31, 2023	4,742	4,462	0	(52)	4,946	(503)	71	280
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(159)	(157)				(157)		(2)
Other comprehensive income (loss), net	(28)	(24)					(24)	(4)
Common stock issued under ESPP	10	10			10
Conversion of non-controlling interest	(79)	190			190			(269)
Share-based compensation expense	73	73			73
Shares withheld in lieu of taxes	(59)	(59)			(59)
Share repurchases	(167)	(167)		(167)
Dividends	(21)	(21)			(21)
Other	1	2			2			(1)
Ending balance at Dec. 31, 2024	4,313	4,309	0	(219)	5,141	(660)	47	4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(3,099)	(3,097)				(3,097)		(2)
Other comprehensive income (loss), net	(27)	(27)					(27)
Common stock issued under ESPP	6	6			6
Conversion of non-controlling interest	1	1			1
Share-based compensation expense	18	18			18
Shares withheld in lieu of taxes	(12)	(12)			(12)
Share repurchases	(65)	(65)		(65)
Dividends	(86)	(86)			(86)
Other	(3)	(3)			(3)
Ending balance at Dec. 31, 2025	$ 1,046	$ 1,044	$ 0	$ (284)	$ 5,065	$ (3,757)	$ 20	$ 2