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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ 61	$ (149)	$ 79	$ 42
Other comprehensive income before reclassifications	(26)	(111)	(11)	75
Amounts reclassified from accumulated other comprehensive income	1	(11)	(3)	(15)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	27	100	8	(90)
Ending Balance	87	(48)	87	(48)
Income Tax Expense (Benefit)	11	2	13	(4)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	142	5	166	151
Other comprehensive income before reclassifications	(25)	(114)	(4)	25
Amounts reclassified from accumulated other comprehensive income	1	(10)	(2)	(17)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	26	104	2	(42)
Ending Balance	168	109	168	109
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(86)	(162)	(92)	(116)
Other comprehensive income before reclassifications	(1)	2	(8)	48
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1	(2)	8	(48)
Ending Balance	(84)	(164)	(84)	(164)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(1)	2	0	(2)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	0	(1)	(1)	2
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	(1)	(1)	2
Ending Balance	(1)	0	(1)	0
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	5	6	5	8
Other comprehensive income before reclassifications	0	0	0	2
Amounts reclassified from accumulated other comprehensive income	0	0	(1)	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	(1)	(2)
Ending Balance	5	6	5	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	(1)	1
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	(1)	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