Supplemental Income Statement Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Supplemental Income Statement Information
Interest expense	$ 82	$ 45
Interest income	(21)	(8)
Pension and postretirement net periodic benefit cost (benefit)	(19)	(32)
Total	$ 42	$ 5