Schedule II - Valuation Accounts and Reserves - Valuation Accounts and Reserves (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts [Member]
Balance at beginning of period	$ 60	$ 59	$ 48
Additions	4	1	11
Balance at end of period	64	60	59
Valuation Allowance of Deferred Tax Assets [Member]
Balance at beginning of period	456	270	238
Additions	17	241	55
Net deductions and other	156	55	23
Balance at end of period	$ 317	456	270
Business Restructuring Reserves [Member]
Balance at beginning of period		5	3
Additions			15
Net deductions and other		$ 5	13
Balance at end of period			$ 5