Segment Reporting - Schedule of Current Reportable and Recast of Segments by Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenue
Revenue	$ 528	$ 538	$ 1,076	$ 1,097
Less
Cost of sales	325	345	676	701
Depreciation and amortization	27	26	53	47
Gross Profit	176	167	347	349
Selling, general and administrative	130	146	234	292
Depreciation and intangible amortization	73	73	148	149
Goodwill impairment	983	0	983	0
Interest expense	22	33	44	64
Net Income (Loss) From Continuing Operations	(1,073)	(4)	(1,090)	(125)
Employer Solutions
Revenue
Revenue	528	538	1,076	1,097
Less
Stock Based Compensation	2	3	5	8
Depreciation and amortization	27	26	53	47
Gross Profit	176	167	347	349
Selling, general and administrative	91	111	188	219
Restructuring	36	18	40	33
Stock Based Compensation	3	17	6	40
Depreciation and intangible amortization	73	73	148	149
Goodwill impairment	983	0	983	0
Interest expense	22	33	44	64
Other segment item	41	(81)	28	(31)
Net Income (Loss) From Continuing Operations	(1,073)	(4)	(1,090)	(125)
Employer Solutions | Technology
Less
Cost of sales	76	82	152	164
Employer Solutions | Delivery, Customer Care, and Other
Less
Cost of sales	247	260	519	529
Employer Solutions | Recurring
Revenue
Revenue	492	493	1,012	1,014
Employer Solutions | Project
Revenue
Revenue	$ 36	$ 45	$ 64	$ 83