Income Tax (Provision for Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ (9)	$ 78	$ 131
Current Federal Tax Expense (Benefit) Relating To US Tax Reform	0	(68)	0
Current Foreign Tax Expense (Benefit)	60	43	37
Current Income Tax Expense (Benefit)	51	53	168
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	182	63	160
Deferred Federal Income Tax Expense (Benefit) Related To US Tax Reform	0	6	(1,034)
Deferred Foreign Income Tax Expense (Benefit)	29	8	27
Deferred income taxes	211	77	(847)
Income Tax Expense (Benefit)	$ 262	$ 130	$ (679)