Business Segments - Capital Expenditures Depreciation and Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Capital expenditures	$ 811	$ 881	$ 996
Depreciation and amortization	778	781	727
Operating Segments
Segment Reporting Information [Line Items]
Capital expenditures	774	848	946
Depreciation and amortization	746	713	678
Operating Segments | Americas
Segment Reporting Information [Line Items]
Capital expenditures	406	525	618
Depreciation and amortization	414	398	366
Operating Segments | Europe, Middle East and Africa
Segment Reporting Information [Line Items]
Capital expenditures	180	159	191
Depreciation and amortization	201	191	192
Operating Segments | Asia Pacific
Segment Reporting Information [Line Items]
Capital expenditures	188	164	137
Depreciation and amortization	131	124	120
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	37	33	50
Depreciation and amortization	$ 32	$ 68	$ 49