Income Taxes (Schedule of Provision for Federal and Foreign Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ 638	$ 245	$ 822
Current Foreign Tax Expense (Benefit)	48	43	40
Current State and Local Tax Expense (Benefit)	0	0	0
Deferred Federal Income Tax Expense (Benefit)	(26)	(42)	235
Deferred Foreign Income Tax Expense (Benefit)	1	15	18
Deferred State and Local Income Tax Expense (Benefit)	(3)	3	(1)
Income Tax Expense (Benefit)	$ 658	$ 264	$ 1,114