Income Taxes, Schedule of Income Taxes Paid (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes Paid, Net
Income taxes paid, net	$ 410	$ 444	$ 2,093
U.S. [Member]
Income Taxes Paid, Net
Income taxes paid, net	239	241	2,092
International [Member]
Income Taxes Paid, Net
Income taxes paid, net	$ 171	$ 203	$ 1