Segment Reporting - Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting, Asset Reconciling Item [Line Items]
Total Revenues	$ 1,652	$ 1,715	$ 1,941	$ 1,751	$ 1,747	$ 1,668	$ 5,121	$ 5,166	$ 7,107
Total Pre-tax income (loss)	63			(380)			59	(474)
Goodwill impairment	0			(412)			0	(412)
Restructuring and related costs, net	(10)			(22)			(35)	(41)
Amortization of intangible assets	(12)			(10)			(33)	(31)
PARC donation	0			0			(132)	0
Accelerated share vesting	0			0			0	(21)
Other expenses, net	17			(1)			(34)	(66)
Depreciation and amortization	63			65			189	205
Amortization of intangible assets	12			10			33	31
Total Interest expense	44			49			140	151
Interest income	49			55			159	164
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total Revenues	1,673			1,774			5,186	5,234
Total Pre-tax income (loss)	68			65			293	97
Depreciation and amortization	51			55			156	174
Total Interest expense	30			28			100	78
Interest income	46			51			147	156
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Total Interest expense	14			21			40	73
Interest income	3			4			12	8
Intersegment revenue
Segment Reporting, Asset Reconciling Item [Line Items]
Total Revenues	$ (21)	$ (23)	$ (22)	$ (23)	$ (22)	$ (23)	$ (65)	$ (68)	$ (90)