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, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (217)	$ (70)	$ (253)	$ 58
Other comprehensive income before reclassifications	(6)	122	(39)	249
Amounts reclassified from accumulated other comprehensive income	2	(4)	5	(5)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	8	(126)	44	(254)
Ending Balance	(209)	(196)	(209)	(196)
Income Tax Expense (Benefit)	2	1	6	1
Realized Investment Gains (Losses)	(3)	7	(8)	17
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(54)	49	(71)	154
Other comprehensive income before reclassifications	15	67	1	171
Amounts reclassified from accumulated other comprehensive income	3	(5)	6	(6)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(13)	(72)	5	(177)
Ending Balance	(67)	(23)	(67)	(23)
Realized Investment Gains (Losses)	3	(7)
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(168)	(123)	(184)	(100)
Other comprehensive income before reclassifications	(21)	55	(37)	78
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	21	(55)	37	(78)
Ending Balance	(147)	(177)	(147)	(177)
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	1	0	1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	1	0	1
Ending Balance	(1)	0	(1)	0
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	6	4	3	4
Other comprehensive income before reclassifications	0	0	(3)	0
Amounts reclassified from accumulated other comprehensive income	0	0	(1)	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	2	0
Ending Balance	6	4	6	4
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)	(1)	2	(2)	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	0	0	(1)	0
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	0	0	(1)	0
Income Tax Expense (Benefit)	$ 0	$ 0	$ 0	$ 0