Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (175)	$ (217)	$ (160)	$ (253)
Other comprehensive income before reclassifications	(9)	(6)	5	(39)
Amounts reclassified from accumulated other comprehensive income	(9)	2	(10)	5
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	8	(15)	44
Ending Balance	(175)	(209)	(175)	(209)
Income Tax Expense (Benefit)	2	2	7	6
Realized Investment Gains (Losses)	4	(3)	4	(8)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(27)	(54)	(20)	(71)
Other comprehensive income before reclassifications	(8)	15	(1)	1
Amounts reclassified from accumulated other comprehensive income	(4)	3	(5)	6
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	4	(13)	(3)	5
Ending Balance	(23)	(67)	(23)	(67)
Realized Investment Gains (Losses)	(4)	3	(4)	8
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(152)	(168)	(144)	(184)
Other comprehensive income before reclassifications	(1)	(21)	7	(37)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1	21	(7)	37
Ending Balance	(151)	(147)	(151)	(147)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(1)	(1)	(1)	(1)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	0	0
Ending Balance	(1)	(1)	(1)	(1)
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	5	6	5	3
Other comprehensive income before reclassifications	0	0	0	(3)
Amounts reclassified from accumulated other comprehensive income	(5)	0	(5)	(1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(5)	0	(5)	2
Ending Balance	0	6	0	6
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Income Tax Expense (Benefit)	0	(1)	0	(2)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Income Tax Expense (Benefit)			0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Other Postretirement Benefits Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0	0	0	0
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Amounts reclassified from accumulated other comprehensive income	(5)	0	(5)	(1)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	0	0
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(5)	0	(5)	(1)
Income Tax Expense (Benefit)	$ 0	$ 0	$ 0	$ 0