Summary of Significant Accounting Policies (Net Interest) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Interest expense	$ 472	$ 374	$ 117
Interest income	(12)	(18)	(14)
Interest expense, net	$ 460	$ 356	$ 103