Income and Other Taxes - Income Tax Expense (Benefit), Current Deferred, by Jurisdiction (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ 45	$ 7	$ (15)
Deferred Federal Income Tax Expense (Benefit)	83	411	(4)
Current Foreign Tax Expense	46	62	71
Deferred Foreign Income Tax Expense (Benefit)	57	(21)	(13)
Current State Tax Expense	31	13	15
Deferred State Income Tax (Benefit) Expense	(5)	9	8
Total Provision	$ 257	$ 481	$ 62