Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (48)	$ 19	$ 42	$ (49)
Other comprehensive income before reclassifications	(74)	(26)	2	(147)
Amounts reclassified from accumulated other comprehensive income	(3)	(19)	(18)	(72)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	71	7	(20)	75
Ending Balance	22	26	22	26
Income Tax Expense (Benefit)	0	3	(5)	33
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	109	157	151	86
Other comprehensive income before reclassifications	(45)	(50)	(20)	(174)
Amounts reclassified from accumulated other comprehensive income	(2)	(18)	(19)	(71)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	42	31	1	103
Ending Balance	152	189	152	189
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(164)	(145)	(116)	(142)
Other comprehensive income before reclassifications	(29)	24	20	28
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	29	(24)	(20)	(28)
Ending Balance	(135)	(169)	(135)	(169)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	0	(2)	(2)	(2)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	0	0	2	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	2	0
Ending Balance	0	(2)	0	(2)
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	6	9	8	9
Other comprehensive income before reclassifications	0	0	2	(1)
Amounts reclassified from accumulated other comprehensive income	0	0	(1)	(1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	(3)	0
Ending Balance	6	9	6	9
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	6
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)	(1)
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Amounts reclassified from accumulated other comprehensive income	0	0	(1)	(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	0	0	(1)	(1)
Income Tax Expense (Benefit)	$ 0	$ 0	$ 0	$ 0