Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Sep. 23, 2024 shares	Jul. 02, 2021 shares	Dec. 31, 2025 USD ($) Vote series $ / shares shares	Dec. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) shares	Feb. 19, 2026 $ / shares	Feb. 13, 2025 USD ($)	Jul. 16, 2024 USD ($)	Jun. 18, 2024 USD ($)	Dec. 31, 2022 shares
Class Of Stock [Line Items]
Preferred stock, shares authorized (in shares)			1,000,000	1,000,000.0
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)			0	0
Preferred stock, shares outstanding (in shares)			0	0
Conversion ratio			1
Increase in equity | $			$ 0	$ 273	$ 344
Additional paid-in-capital deferred tax liabilities | $			1	11	43
Remaining authorized amount for future share repurchase program | $			216
Share repurchases | $			(65)	(167)	(40)
Treasury
Class Of Stock [Line Items]
Share repurchases | $			$ (65)	$ (167)	$ (40)
Shares repurchases (in shares)			13,881,417	22,327,717	4,921,468
Barclays Bank PLC | Accelerated Share Repurchase
Class Of Stock [Line Items]
Common stock repurchase, authorized amount | $									$ 75
Accelerated share repurchase payments | $								$ 75
Percentage of shares equal to the settlement amount								80.00%
Tax Receivable Agreement Liability
Class Of Stock [Line Items]
Additional TRA liabilities | $			$ 0	$ 90	$ 109
Class A Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			523,941,625	531,700,000
Common shares, votes per share | Vote			1
Common stock, shares issued (in shares)			566,500,000	560,500,000
Common stock, shares authorized (in shares)			1,000,000,000	1,000,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001	$ 0.0001
Conversion of noncontrolling interest (in shares)			25,879	28,987,597	34,519,247
Shares repurchases (in shares)			13,881,417	22,327,717	4,921,468
Common stock repurchase, additional authorized amount | $							$ 200
Class A Common Stock | Subsequent Events
Class Of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares						$ 0.0001
Class A Common Stock | Accelerated Share Repurchase
Class Of Stock [Line Items]
Accelerated share repurchase payments | $				$ 75
Shares repurchases (in shares)	2,400,041			10,563,306
Class B Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			9,900,000	10,000,000.0
Issuance of common units (in shares)		14,999,998
Number of common stock instruments | series			2
Common stock, shares issued (in shares)			9,900,000	10,000,000.0
Common stock, shares authorized (in shares)			20,000,000.0	20,000,000.0
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001	$ 0.0001
Class B-1 Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			4,955,297
Common stock, shares issued (in shares)			4,955,297
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger (in dollars per share) | $ / shares			$ 12.50
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis (in dollars per share) | $ / shares			$ 12.50
Class B-1 Common Units | Alight Holdings
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			2,544,702
Common stock, shares issued (in shares)			2,544,702
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger (in dollars per share) | $ / shares			$ 12.50
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis (in dollars per share) | $ / shares			$ 12.50
Class B-2 Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			4,955,297
Common stock, shares issued (in shares)			4,955,297
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger (in dollars per share) | $ / shares			$ 15.00
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis (in dollars per share) | $ / shares			$ 15.00
Class B-2 Common Units | Alight Holdings
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			2,544,702
Common stock, shares issued (in shares)			2,544,702
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger (in dollars per share) | $ / shares			$ 15.00
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis (in dollars per share) | $ / shares			$ 15.00
Class B-3 Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			0
Common stock, shares issued (in shares)			0
Common stock, shares authorized (in shares)			10,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001
Class V Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			484,358	510,237	28,962,218					63,481,465
Common shares, votes per share | Vote			1
Common stock, shares issued (in shares)			500,000	500,000
Common stock shares conversion ratio			1
Common stock, shares authorized (in shares)			175,000,000.0	175,000,000.0
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001	$ 0.0001
Shares issued (in shares)			484,358
Conversion of noncontrolling interest (in shares)			(25,879)	(28,987,597)	(34,519,247)
Class Z Common Stock
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			0	0	3,420,215					5,595,577
Common stock, shares issued (in shares)		8,671,507	0	0
Common stock, shares authorized (in shares)			12,900,000	12,900,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.0001	$ 0.0001
Class Z Common Units
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			0
Class A Units
Class Of Stock [Line Items]
Common stock, shares outstanding (in shares)			524,425,983
Held by non controlling interest (in shares)			484,358