Debt and Borrowing Arrangements - Interest and Other Expense Net Within Results of Continuing Operations (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Interest expense, debt					$ 484	$ 462	$ 396
Loss on debt extinguishment and related expenses	$ 0	$ 0	$ 140	$ 0	0	140	11
Loss/(gain) related to interest rate swaps					111	(10)	0
Other (income)/expense, net					(139)	(72)	(25)
Interest and other expense, net					$ 456	$ 520	$ 382