Investments in Securities Other-than-temporary Impairments 1 (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 36	$ 635	$ 1,100
Accumulated Other Comprehensive Income (Loss), Net of Tax, Available-for-sale Securities, Other-than-temporary Impairment not Recorded	97	52	87
Accumulated Other Comprehensive Income (Loss), Net of Tax, Available-for-sale Gain (Loss), Other-than-temporary Impairment Recorded	0	224	423
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	34	46	43
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 131	$ 322	$ 553