Income Tax (Provision for Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 75	$ (9)	$ 78
Current Federal Tax Expense (Benefit) Relating To US Tax Reform	0	0	(68)
Current Foreign Tax Expense (Benefit)	79	60	43
Current Income Tax Expense (Benefit)	154	51	53
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	(60)	182	63
Deferred Federal Income Tax Expense (Benefit) Related To US Tax Reform	0	0	6
Deferred Foreign Income Tax Expense (Benefit)	44	29	8
Deferred income taxes	(16)	211	77
Income Tax Expense (Benefit)	$ 138	$ 262	$ 130