Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 113	$ 116	$ 101
Additions, charged (credited) to income	13	21	12
Additions, charged (credited) to AOCL	0	0	0
Deductions from reserves	(14)	(19)	(6)
Translation adjustment during period	(1)	(5)	9
Balance at end of period	111	113	116
Valuation allowance — deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	317	318	326
Additions, charged (credited) to income	661	18	(19)
Additions, charged (credited) to AOCL	4	(1)	0
Deductions from reserves	0	0	0
Translation adjustment during period	0	(18)	11
Balance at end of period	$ 982	$ 317	$ 318